[Federal Register Volume 88, Number 86 (Thursday, May 4, 2023)]
[Rules and Regulations]
[Pages 28780-28871]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-08128]



[[Page 28779]]

Vol. 88

Thursday,

No. 86

May 4, 2023

Part III





Department of Energy





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10 CFR Parts 429 and 431





Energy Conservation Program: Test Procedures for Walk-In Coolers and 
Walk-In Freezers; Final Rule

  Federal Register / Vol. 88, No. 86 / Thursday, May 4, 2023 / Rules 
and Regulations  

[[Page 28780]]


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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2017-BT-TP-0010]
RIN 1904-AD78


Energy Conservation Program: Test Procedures for Walk-In Coolers 
and Walk-In Freezers

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 
Energy.

ACTION: Final rule.

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SUMMARY: The U.S. Department of Energy (DOE) is amending the test 
procedures for walk-in coolers and walk-in freezers to harmonize with 
updated industry standards, revise certain definitions, revise the test 
methods to more accurately represent field energy use, and to 
accommodate a wider range of walk-in cooler and walk-in freezer 
component equipment designs.

DATES: The effective date of this rule is June 5, 2023. The amendments 
will be mandatory for product testing starting October 31, 2023. 
Manufacturers will be required to use the amended test procedures until 
the compliance date of any final rule establishing amended energy 
conservation standards based on the newly established test procedures. 
At such time, manufacturers will be required to begin using the newly 
established test procedures.
    The incorporation by reference of certain materials listed in the 
rule is approved by the Director of the Federal Register on June 5, 
2023. The incorporation by reference of certain other material listed 
in the rule was approved by the Director of the Federal Register on 
January 27, 2017.

ADDRESSES: The docket, which includes Federal Register notices, public 
meeting attendee lists and transcripts, comments, and other supporting 
documents/materials, is available for review at www.regulations.gov. 
All documents in the docket are listed in the www.regulations.gov 
index. However, not all documents listed in the index may be publicly 
available, such as those containing information that is exempt from 
public disclosure.
    A link to the docket web page can be found at www.regulations.gov/docket/EERE-2017-BT-TP-0010. The docket web page contains instructions 
on how to access all documents, including public comments, in the 
docket.
    For further information on how to review the docket contact the 
Appliance and Equipment Standards Program staff at (202) 287-1445 or by 
email: [email protected].

FOR FURTHER INFORMATION CONTACT: Ms. Catherine Rivest, U.S. Department 
of Energy, Office of Energy Efficiency and Renewable Energy, Building 
Technologies Office, EE-5B, 1000 Independence Avenue SW, Washington, DC 
20585-0121. Telephone: (202) 586-7335. Email: 
[email protected].
    Mr. Matthew Schneider, U.S. Department of Energy, Office of the 
General Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 
20585-0121. Telephone: (240) 597-6265. Email: 
[email protected].

SUPPLEMENTARY INFORMATION: DOE maintains a previously approved 
incorporation by reference and incorporates by reference the following 
industry standards into part 431:
    AHRI Standard 1250-2020, ``2020 Standard for Performance Rating of 
Walk-in Coolers and Freezers.''
    Copies of AHRI 1250-2020 can be obtained from the Air-Conditioning, 
Heating, and Refrigeration Institute, 2111 Wilson Blvd., Suite 400, 
Arlington, VA 22201 or at www.ahrinet.org.
    ANSI/ASHRAE 16-2016, ``Method of Testing for Rating Room Air 
Conditioners, Packaged Terminal Air Conditioners, and Packaged Terminal 
Heat Pumps for Cooling and Heating Capacity''.
    ANSI/ASHRAE 23.1-2010, ``Methods of Testing for Rating the 
Performance of Positive Displacement Refrigerant Compressors and 
Condensing Units that Operate at Subcritical Temperatures of the 
Refrigerant''.
    ANSI/ASHRAE 37-2009, ``Methods of Testing for Rating Electrically 
Driven Unitary Air-Conditioning and Heat-Pump Equipment''.
    ANSI/ASHRAE 41.1-2013, ``Standard Method for Temperature 
Measurement''.
    ANSI/ASHRAE 41.3-2014, ``Standard Methods for Pressure 
Measurement''.
    ANSI/ASHRAE 41.6-2014, ``Standard Method for Humidity 
Measurement''.
    ANSI/ASHRAE 41.10-2013, ``Standard Methods for Refrigerant Mass 
Flow Measurement Using Flowmeters''.
    Copies of ANSI/ASHRAE 16-2016, ANSI/ASHRAE 23.1-2010, ANSI/ASHRAE 
37-2009, ANSI/ASHRAE 41.1-2013, ANSI/ASHRAE 41.3-2014, ANSI/ASHRAE 
41.6-2014, and ANSI/ASHRAE 41.10-2013, can be obtained from the 
American Society of Heating, Refrigerating and Air-Conditioning 
Engineers, 180 Technology Parkway NW, Peachtree Corners, GA 30092, or 
at www.ashrae.org.
    ASTM C518-17, ``Standard Test Method for Steady-State Thermal 
Transmission Properties by Means of the Heat Flow Meter Apparatus''.
    ASTM C1199-14, ``Standard Test Method for Measuring the Steady-
State Thermal Transmittance of Fenestration Systems Using Hot Box 
Methods.''
    Copies of ASTM C518-17 and ASTM C1199-14 can be obtained from ASTM 
International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, 
PA 19428-2959, or at www.astm.org.
    NFRC 102-2020 [E0A0], ``Procedure for Measuring the Steady-State 
Thermal Transmittance of Fenestration Systems''
    Copies of NFRC 102-2020 can be obtained from the National 
Fenestration Rating Council, 6305 Ivy Lane, Suite 140, Greenbelt, MD 
20770, or at www.nfrc.org.
    See section IV.N of this document for a further discussion of these 
standards.

Table of Contents

I. Authority and Background
    A. Authority
    B. Background
II. Synopsis of the Final Rule
III. Discussion
    A. Scope and Definitions
    1. Scope
    2. Definitions
    B. Updates to Industry Standards
    1. Industry Standards for Determining Thermal Transmittance (U-
factor)
    2. Industry Standard for Determining R-Value
    3. Industry Standards for Determining AWEF
    C. Amendments to Appendix A for Doors
    1. Reference to NFRC 102-2020 in Place of NFRC 100-2010 and 
Alternative Efficiency Determination Methods for Doors
    2. Additional Definitions
    3. Electrical Door Components
    4. Percent Time Off Values
    5. Energy Efficiency Ratio Values
    6. Air Infiltration Reduction
    D. Amendments to Appendix A for Display Panels
    E. Amendments to the Appendix B for Panels and Non-Display Doors
    1. 24-Hour Testing Window
    2. Total Insulation and Test Specimen Thickness
    3. Parallelism and Flatness
    4. Insulation Aging
    5. Overall Thermal Transmittance of Non-Display Panels
    F. Amendments to Appendix C for Refrigeration Systems
    1. Refrigeration Test Room Conditioning
    2. Temperature Measurement Requirements
    3. Hierarchy of Installation Instruction and Specified 
Refrigerant Conditions for Refrigerant Charging and Setting 
Refrigerant Conditions
    4. Subcooling Requirement for Mass Flow Meters
    5. Instrument Accuracy and Test Tolerances
    6. CO2 Unit Coolers
    7. High-Temperature Unit Coolers

[[Page 28781]]

    G. Establishing Appendix C1 for Refrigeration Systems
    1. Off-Cycle Power Consumption
    2. Single-Packaged Dedicated Systems
    3. Detachable Single-Packaged Dedicated Systems
    4. Attached Split Systems
    5. Systems for High-Temperature Freezer Applications
    6. Systems for High-Temperature Applications
    7. Variable-, Two-, and Multiple-Capacity Systems
    8. Defrost
    9. Refrigerant Glide
    10. Refrigerant Temperature and Pressure Instrumentation 
Locations
    11. Updates to Default Values for Unit Cooler Parameters
    12. Calculations and Rounding
    H. Alternative Efficiency Determination Methods for 
Refrigeration Systems
    I. Sampling Plan for Enforcement Testing
    J. Organizational Changes
    K. Test Procedure Costs and Impact
    1. Doors
    2. Panels
    3. Refrigeration Systems
    L. Effective and Compliance Dates
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Orders 12866 and 13563
    B. Review Under the Regulatory Flexibility Act
    C. Review Under the Paperwork Reduction Act of 1995
    D. Review Under the National Environmental Policy Act of 1969
    E. Review Under Executive Order 13132
    F. Review Under Executive Order 12988
    G. Review Under the Unfunded Mandates Reform Act of 1995
    H. Review Under the Treasury and General Government 
Appropriations Act, 1999
    I. Review Under Executive Order 12630
    J. Review Under Treasury and General Government Appropriations 
Act, 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
    M. Congressional Notification
    N. Description of Materials Incorporated by Reference
V. Approval of the Office of the Secretary

I. Authority and Background

    Walk-in coolers and walk-in freezers (collectively ``WICFs'' or 
``walk-ins'') are included in the list of ``covered equipment'' for 
which the U.S. Department of Energy (DOE) is authorized to establish 
and amend energy conservation standards and test procedures. (42 U.S.C. 
6311(1)(G)) DOE's energy conservation standards and test procedures for 
WICFs are currently prescribed at subpart R of part 431 of title 10 of 
the Code of Federal Regulations (CFR). The following sections discuss 
DOE's authority to establish test procedures for WICFs and relevant 
background information regarding DOE's consideration of test procedures 
for this equipment.

A. Authority

    The Energy Policy and Conservation Act, Public Law 94-163, as 
amended (``EPCA''),\1\ authorizes DOE to regulate the energy efficiency 
of a number of consumer products and certain industrial equipment. (42 
U.S.C. 6291-6317) Title III, Part C of EPCA \2\ established the Energy 
Conservation Program for Certain Industrial Equipment, which sets forth 
a variety of provisions designed to improve energy efficiency. This 
equipment includes WICFs, the subject of this document. (42 U.S.C. 
6311(1)(G))
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    \1\ All references to EPCA in this document refer to the statute 
as amended through the Energy Act of 2020, Public Law 116-260 (Dec. 
27, 2020), which reflect the last statutory amendments that impact 
Parts A and A-1 of EPCA.
    \2\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
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    The energy conservation program under EPCA consists essentially of 
four parts: (1) testing, (2) labeling, (3) Federal energy conservation 
standards, and (4) certification and enforcement procedures. Relevant 
provisions of EPCA include definitions (42 U.S.C. 6311), test 
procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315), 
energy conservation standards (42 U.S.C. 6313), and the authority to 
require information and reports from manufacturers (42 U.S.C. 6316).
    The Federal testing requirements consist of test procedures that 
manufacturers of covered equipment must use as the basis for: (1) 
certifying to DOE that their equipment complies with the applicable 
energy conservation standards adopted pursuant to EPCA (42 U.S.C. 
6316(a); 42 U.S.C. 6295(s)), and (2) making other representations about 
the efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE 
must use these test procedures to determine whether the equipment 
complies with relevant standards promulgated under EPCA. (42 U.S.C. 
6316(a); 42 U.S.C. 6295(s))
    Federal energy efficiency requirements for covered equipment 
established under EPCA generally supersede State laws and regulations 
concerning energy conservation testing, labeling, and standards. (42 
U.S.C. 6316(a) and 42 U.S.C. 6316(b); 42 U.S.C. 6297) DOE may, however, 
grant waivers of Federal preemption for particular State laws or 
regulations, in accordance with the procedures and other provisions of 
EPCA. (42 U.S.C. 6316(b)(2)(D))
    Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures 
DOE must follow when prescribing or amending test procedures for 
covered equipment. EPCA requires that any test procedures prescribed or 
amended under this section must be reasonably designed to produce test 
results that reflect energy efficiency, energy use, or estimated annual 
operating cost of a given type of covered equipment during a 
representative average use cycle (as determined by the Secretary) and 
requires that test procedures not be unduly burdensome to conduct. (42 
U.S.C. 6314(a)(2))
    EPCA also requires that, at least once every 7 years, DOE evaluate 
test procedures for each type of covered equipment, including WICFs, to 
determine whether amended test procedures would more accurately or 
fully comply with the requirements for the test procedures to not be 
unduly burdensome to conduct and be reasonably designed to produce test 
results that reflect energy efficiency, energy use, and estimated 
operating costs during a representative average use cycle. (42 U.S.C. 
6314(a)(1)) DOE considers this rulemaking to be in satisfaction of the 
7-year review requirement specified in EPCA.
    In addition, if the Secretary determines that a test procedure 
amendment is warranted, the Secretary must publish proposed test 
procedures in the Federal Register, and afford interested persons an 
opportunity (of not less than 45 days duration) to present oral and 
written data, views, and arguments on the proposed test procedures. (42 
U.S.C. 6314(b)) If DOE determines that test procedure revisions are not 
appropriate, DOE must publish its determination not to amend the test 
procedures. (42 U.S.C. 6314(a)(1)(A)(ii))

B. Background

    For measuring walk-in energy use, DOE has established separate test 
procedures for the principal components that may comprise a walk-in 
(i.e., doors, panels, and refrigeration systems), with separate test 
metrics for each component. (10 CFR 431.304(b)) For walk-in doors and 
display panels, the efficiency metric is daily energy consumption, 
measured in kilowatt-hours per day (kWh/day), which accounts for the 
thermal conduction through the door or display panel and the direct and 
indirect electricity use of any electrical components associated with 
the door. See 10 CFR 431.304(b)(1)-(2) and 10 CFR part 431, subpart R, 
appendix A, ``Uniform Test Method for the Measurement of Energy 
Consumption of the Components of Envelopes of Walk-in Coolers and Walk-
in Freezers'' (appendix A). The thermal transmittance through the door, 
which inputs into the calculation of thermal

[[Page 28782]]

conduction, is determined using National Fenestration Rating Council 
(NFRC) 100-2010, ``Procedure for Determining Fenestration U-factors'' 
(NFRC 100-2010), which is incorporated by reference at 10 CFR 431.303.
    For walk-in non-display panels and non-display doors, in the final 
rule published on April 15, 2011, DOE codified in the CFR the standards 
established in EPCA based on the R-value metric,\3\ expressed in units 
of (h-ft\2\-[deg]F/Btu),\4\ which is calculated as the thickness of the 
panel in inches (in.) divided by the K-factor.\5\ See 10 CFR 
431.304(b)(3) and 10 CFR part 431, subpart R, appendix B, ``Uniform 
Test Method for the Measurement of R-Value for Envelope Components of 
Walk-in Coolers and Walk-in Freezers'' (appendix B). (See also 42 
U.S.C. 6314(a)(9)(A)) The K-factor is calculated based on ASTM 
International (ASTM) C518, ``Standard Test Method for Steady-State 
Thermal Transmission Properties by Means of the Heat Flow Meter 
Apparatus'' (ASTM C518), which is incorporated by reference at 10 CFR 
431.303. Id.
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    \3\ The R-value is the thermal resistance, or the capacity of an 
insulated material to resist heat flow. See section 3.3.3 of ASTM 
C518. See 42 U.S.C. 6313(f)(1)(C) for the EPCA R-value requirements 
for non-display panels and doors.
    \4\ These symbols represent the following units of measurement--
h: hour; ft\2\: square foot; [deg]F: degrees Fahrenheit; Btu: 
British thermal unit.
    \5\ The K-factor represents the thermal conductivity of a 
material, or its ability to conduct heat, in units of Btu-in/(h-
ft\2\-[deg]F). See section 3.3.1 of ASTM C518.
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    For walk-in refrigeration systems, the efficiency metric is the 
annual walk-in energy factor (``AWEF''), which is the ratio of the 
total heat, not including the heat generated by the operation of 
refrigeration systems, removed, in Btu, from a walk-in box during a 
one-year period of usage for refrigeration to the total energy input of 
refrigeration systems, in watt-hours, during the same period. AWEF is 
determined by conducting the test procedure set forth in American 
National Standards Institute (ANSI)/Air-Conditioning, Heating, and 
Refrigeration Institute (AHRI) Standard 1250 (I-P), ``2009 Standard for 
Performance Rating of Walk-in Coolers and Freezers'' (AHRI 1250-2009), 
which is incorporated by reference in 10 CFR 431.303 with certain 
adjustments specified in the CFR. See 10 CFR 431.304(b)(4) and 10 CFR 
part 431, subpart R, appendix C, ``Uniform Test Method for the 
Measurement of Net Capacity and AWEF of Walk-in Cooler and Walk-in 
Freezer Refrigeration Systems'' (appendix C). A manufacturer may also 
determine AWEF using an alternative efficiency determination method 
(AEDM). 10 CFR 429.53(a)(2)(iii). An AEDM enables a manufacturer to 
utilize computer-based or mathematical models for purposes of 
determining an equipment's energy use or energy efficiency performance 
in lieu of testing, provided certain prerequisites have been met. 10 
CFR 429.70(f).
    On August 5, 2015, DOE published its intention to establish a 
working group under the Appliance Standards and Rulemaking Federal 
Advisory Committee (ASRAC) to negotiate energy conservation standards 
to replace the standards established in the final rule published on 
June 3, 2014 (79 FR 32050, ``June 2014 ECS Final Rule''). 80 FR 46521. 
The established working group (ASRAC Working Group) assembled its 
recommendations into a term sheet \6\ (Docket No. EERE-2015-BT-STD-
0016, No. 56) that was presented to and approved by ASRAC on December 
18, 2015 (ASRAC Term Sheet).
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    \6\ Appliance Standards and Rulemaking Federal Advisory 
Committee Refrigeration Systems Walk-in Coolers and Freezers Term 
Sheet, available at www.regulations.gov/document/EERE-2015-BT-STD-
0016-0056.
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    The ASRAC Term Sheet provided recommendations for energy 
conservation standards to replace standards vacated by the United 
States Court of Appeals for the Fifth Circuit in a controlling order 
issued August 10, 2015. It also included recommendations regarding 
definitions for a number of terms related to the WICF regulations, as 
well as recommendations to amend the test procedure that the ASRAC 
Working Group viewed as necessary to properly implement the energy 
conservation standards recommendations. Consequently, in 2016 DOE 
initiated both an energy conservation standards rulemaking and a test 
procedure rulemaking to implement these recommendations. The ASRAC Term 
Sheet also included recommendations for future amendments to the test 
procedures intended to make DOE's test procedures more fully 
representative of walk-in energy use.
    On December 28, 2016, DOE published a final rule amending the WICF 
test procedures (``December 2016 Final Rule''), consistent with the 
ASRAC Term Sheet recommendations and including provisions to facilitate 
implementation of energy conservation standards for walk-in components. 
81 FR 95758.
    In 2020, AHRI published an updated industry test standard for walk-
in refrigeration systems, ``2020 Standard for Performance Rating of 
Walk-in Coolers and Freezers,'' (AHRI 1250-2020) updating the existing 
AHRI standard ``AHRI 1250P (I-P)-2009.'' This new test procedure 
included updated calculations for the determination of default values 
for equipment with electric defrost and hot gas defrost. DOE published 
a final rule for hot gas defrost unit coolers on March 26, 2021 (March 
2021 Final Rule), that amended the test procedure to rate hot gas 
defrost unit coolers using the modified default values for energy use 
and heat load contributions in AHRI 1250-2020. These amendments ensure 
that ratings for hot gas defrost unit coolers are consistent with those 
of electric defrost unit coolers. 86 FR 16027.
    Under 10 CFR 431.401, any interested person may submit a petition 
for waiver from DOE's test procedure requirements. DOE will grant a 
waiver from the test procedure requirements if DOE determines either 
the basic model for which the waiver was requested contains a design 
characteristic that prevents testing of the basic model according to 
the prescribed test procedures, or the prescribed test procedures 
evaluate the basic model in a manner so unrepresentative of its true 
energy consumption characteristics as to provide materially inaccurate 
comparative data. 10 CFR 431.401(f)(2). DOE may grant the waiver 
subject to conditions, including adherence to alternate test procedures 
specified by DOE. Id. DOE has granted interim waivers and/or waivers to 
the manufacturers listed in Table I.1.

              Table I.1--Manufacturers Who Received a Test Procedure Waiver/Interim Waiver From DOE
----------------------------------------------------------------------------------------------------------------
                                                                                                   Waiver from
                 Manufacturer                               Subject                 Case No.         appendix
----------------------------------------------------------------------------------------------------------------
Jamison Door Company.........................  Percent Time Off (PTO) for Door         2017-009               A
                                                Motors.
HH Technologies..............................  PTO for Door Motors.............        2018-001               A

[[Page 28783]]

 
Senneca Holdings.............................  PTO for Door Motors.............        2020-002               A
Hercules.....................................  PTO for Door Motors.............        2020-013               A
Heat Transfer Products Group, LLC (HTPG).....  CO2 Unit Coolers................        2020-009                C
Hussmann Corporation (Hussmann)..............  CO2 Unit Coolers................        2020-010                C
KeepRite Refrigeration, Inc. (KeepRite)......  CO2 Unit Coolers................        2020-014                C
RefPlus, Inc.................................  CO2 Unit Coolers................        2021-006                C
Refrigerated Solutions Group (RSG)...........  Multi-Circuit Single-Package            2022-004                C
                                                Dedicated Systems.
Store It Cold................................  Single-Packaged Dedicated               2018-002                C
                                                Systems.
CellarPro....................................  Wine Cellar Refrigeration               2019-009                C
                                                Systems.
Air Innovations..............................  Wine Cellar Refrigeration               2019-010                C
                                                Systems.
Vinotheque...................................  Wine Cellar Refrigeration               2019-011                C
                                                Systems.
Vinotemp.....................................  Wine Cellar Refrigeration               2020-005                C
                                                Systems.
LRC Coil Company (LRC Coil)..................  Wine Cellar Refrigeration               2020-024                C
                                                Systems.
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    On June 17, 2021, DOE published a request for information (RFI) to 
initiate a test procedure rulemaking for walk-ins (June 2021 RFI). 86 
FR 32332. DOE published a notice of proposed rulemaking (NOPR) on April 
21, 2022 (April 2022 NOPR), responding to comments received in response 
to the June 2021 RFI and presenting DOE's proposals to amend the WICFs 
test procedure--including amendments to eliminate the need for existing 
test procedure waivers--and establish a new test procedure at 10 CFR 
part 431, subpart R, appendix C1 (appendix C1), that would establish a 
new energy efficiency metric, AWEF2. 87 FR 23920. DOE held a public 
meeting related to the April 2022 NOPR on May 9, 2022.
    DOE received comments in response to the April 2022 NOPR from the 
interested parties listed in Table I.2.

            Table I.2--List of Commenters With Written Submissions in Response to the April 2022 NOPR
----------------------------------------------------------------------------------------------------------------
                                            Reference in this Final   Comment No. in
              Commenter(s)                           Rule               the docket          Commenter type
----------------------------------------------------------------------------------------------------------------
Air-Conditioning, Heating, &              AHRI \7\..................              30  Trade Association.
 Refrigeration Institute.
Air-Conditioning, Heating, &              AHRI-Wine \8\.............              30  Trade Association.
 Refrigeration Institute.
Anthony International...................  Anthony...................              31  Manufacturer.
Appliance Standards Awareness Project,    Efficiency Advocates......              37  Efficiency Organizations.
 American Council for an Energy-
 Efficient Economy, Natural Resources
 Defense Council, Northwest Energy
 Efficiency Alliance.
Bally Refrigerated Boxes, Inc...........  Bally.....................              40  Manufacturer.
Heat Transfer Products Group, LLC.......  HTPG......................              32  Manufacturer.
Hussmann Corporation....................  Hussmann..................          34, 38  Manufacturer.
KeepRite Refrigeration, Inc.............  KeepRite..................              36  Manufacturer.
Lennox International Inc................  Lennox....................              35  Manufacturer.
National Refrigeration & Air              National Refrigeration....              39  Manufacturer.
 Conditioning Canada Corp.
North American Association of Food        NAFEM.....................              33  Trade Association.
 Equipment.
Pacific Gas and Electric Company, San     CA IOUs...................              42  Utility Association.
 Diego Gas & Electric, and Southern
 California Edison; collectively, the
 California Investor-Owned Utilities.
Refrigerated Solutions Group............  RSG.......................              41  Manufacturer.
Senneca Holdings........................  Senneca...................              26  Manufacturer.
----------------------------------------------------------------------------------------------------------------

    A parenthetical reference at the end of a comment quotation or 
paraphrase provides the location of the item in the public record.\9\ 
To the extent that interested parties have provided written comments 
that are substantively consistent with any oral comments provided 
during the May 2022 public meeting, DOE cites the written comments 
throughout this final rule.
---------------------------------------------------------------------------

    \7\ AHRI submitted two comment documents to the docket. The 
first document in the docket includes AHRI's comments for 
traditional walk-in manufacturers (i.e., medium- and low-temperature 
walk-in components). The associated file name in the docket is: AHRI 
Comments WICF NOPR EERE-2017-BT-TP-0010. These comments are 
referenced in this document as ``AHRI'' comments.
    \8\ AHRI submitted two comment documents to the docket. The 
second document in the docket includes AHRI's comments supporting 
wine cellar manufacturers (i.e., high-temperature walk-in 
refrigeration systems). The associated file name in the docket is: 
Comments WICF NOPR EERE-2017-BT-TP-0010 Wine. These comments are 
referenced in this document as ``AHRI-Wine'' comments.
    \9\ The parenthetical reference provides a reference for 
information located in the docket of DOE's rulemaking to develop 
test procedures for walk-ins (Docket No. EERE-2017-BT-TP-0010, 
maintained at www.regulations.gov). The references are arranged as 
follows: (commenter name, comment docket ID number, page of that 
document).
---------------------------------------------------------------------------

    In response to the April 2022 NOPR, NAFEM commented that while the 
April 2022 NOPR was not inconsistent with DOE's Process Rule,\10\ NAFEM 
supports the U.S. Small Business Administration Office of Advocacy 
request \11\ that DOE reopen public comment on the 2021 Process Rule 
and

[[Page 28784]]

concurrent proposed rulemaking.\12\ (NAFEM, No. 33 at p. 2) The request 
referenced by NAFEM specifically refers to a National Academies of 
Sciences (``NAS'') report entitled ``Review of Methods Used by the U.S. 
Department of Energy in Setting Appliance and Equipment Standards.'' 
Given that the recommendations in the NAS report pertain to the 
processes by which DOE analyzes energy conservation standards, DOE will 
consider this comment in a separate rulemaking that includes all 
product categories.
---------------------------------------------------------------------------

    \10\ The term ``Process Rule'' refers to DOE's Procedures, 
Interpretations, and Policies for Consideration of New or Revised 
Energy Conservation Standards and Test Procedures for Consumer 
Products and Certain Commercial/Industrial Equipment at 10 CFR part 
430, subpart C, appendix A.
    \11\ The U.S. Small Business Administration Office of Advocacy 
request is available at cdn.advocacy.sba.gov/wp-content/uploads/2022/05/13104422/Comment-Letter-DOE-Process-Rule-Letter_5-13-22.pdf.
    \12\ DOE published a NOPR and request for comment on July 7, 
2021, proposing changes to the Process Rule. 86 FR 35668.
---------------------------------------------------------------------------

II. Synopsis of the Final Rule

    In this final rule, DOE is expanding the scope of its walk-in 
coolers and freezers test procedure to include carbon dioxide 
(CO2) unit coolers, multi-circuit single-packaged dedicated 
systems, and ducted fan coil units. DOE has also determined that 
liquid-cooled refrigeration systems are within the scope of DOE 
coverage authority for walk-ins but is not adding an applicable test 
procedure at this time.
    In this final rule, DOE is amending the definitions of walk-in 
cooler and walk-in freezer, door, door surface area, and single-
packaged dedicated systems. DOE is also adding new definitions for door 
leaf, hinged vertical door, non-display door, roll-up door, sliding 
door, high-temperature refrigeration systems, ducted fan coil units, 
multi-circuit single-packaged dedicated systems, ducted multi-circuit 
single-packaged dedicated systems, attached split systems, detachable 
single-packaged dedicated systems, and CO2 unit coolers.
    In this final rule, DOE is revising appendix A as follows: (1) 
incorporate by reference NFRC 102-2020 as the applicable test procedure 
to determine door ``U-factor'' in place of NFRC 100-2010; \13\ (2) 
provide further detail on and distinguish the area to be used for 
calculating a thermal load from U-factor and determining compliance 
with standards; (3) establish a percent time off (``PTO'') specific to 
door motors; and (4) reorganize appendix A so it is easier to follow.
---------------------------------------------------------------------------

    \13\ As discussed further in section III.C.1.b of this final 
rule, DOE is also adopting AEDM provisions for doors in 10 CFR 
429.53 to allow calculation of door energy use representations.
---------------------------------------------------------------------------

    Additionally, DOE is modifying appendix B to improve test 
representativeness and repeatability. Specifically, DOE is revising 
appendix B as follows: (1) reference the updated industry standard ASTM 
C518-17; (2) include more detailed provisions for determining measuring 
insulation thickness and test specimen thickness; (3) provide 
additional specifications for determining parallelism and flatness of a 
test specimen; and (4) reorganize appendix B as a step-by-step 
procedure to improve readability.
    DOE is also including walk-in doors and walk-in panels in the list 
of covered equipment in the same sampling plan for enforcement testing 
that is used for walk-in refrigeration systems. (See 10 CFR 
429.110(e)(2))
    In this final rule, DOE is making two sets of changes to the 
refrigeration system test procedure. One set of changes is grouped into 
revisions to appendix C, and the other set of changes is included in a 
new appendix C1. DOE has determined that the changes to appendix C will 
not affect AWEF ratings and therefore will not require any retesting or 
recertification. These changes will be required starting 180 days after 
the test procedure final rule is published. DOE is also establishing a 
new metric, AWEF2, in the new appendix C1, which will require retesting 
and recertification. Use of appendix C1 will not be required until the 
compliance date of amended energy conservation standards for WICFs that 
DOE may ultimately adopt as part of a separate rulemaking.
    DOE is revising appendix C, as follows:
    (1) Specify refrigeration test room conditions.
    (2) Provide for a temperature probe exception for small diameter 
refrigerant lines.
    (3) Incorporate a test setup hierarchy of installation instructions 
for laboratories to follow when setting up a unit for test.
    (4) Allow active cooling of the liquid line in order to achieve the 
required 3 [deg]F subcooling at a refrigerant mass flow meter.
    (5) Modify instrument accuracy and test tolerances.
    (6) Address current test procedure waivers for CO2 unit 
coolers tested alone and high-temperature unit coolers tested alone by 
incorporating amendments appropriate for this equipment.
    The new appendix C1 includes these changes to appendix C, as well 
as the following additional changes:
    (1) Adopt AHRI 1250-2020.
    (2) Provide for testing single-packaged dedicated systems, 
detachable single-packaged dedicated systems; attached split systems; 
CO2, variable-, two-, and multiple-capacity dedicated 
condensing units; indoor variable-, two-, and multiple-capacity matched 
pairs; matched refrigeration systems for high-temperature applications; 
and multi-circuit single-packaged dedicated systems.
    (3) Add a single-packaged dedicated system refrigerant enthalpy 
test procedure.
    (4) Add a new energy efficiency metric, AWEF2, to reflect the 
changes in the test procedure that would result in a significant change 
to energy use values compared to the AWEF metric in appendix C.
    Table II.1 summarizes the current DOE test procedure, DOE's changes 
to the test procedure, the attribution for each proposed change, and 
the relevant test procedure appendix.

               Table II.1--Summary of Changes in Test Procedure Relative to Current Test Procedure
----------------------------------------------------------------------------------------------------------------
                                     DOE test procedure       Amended test                             Relevant
         WICF component(s)           prior to amendment         procedure            Attribution       appendix
----------------------------------------------------------------------------------------------------------------
Doors and Display Panels..........  Incorporates by       Incorporates by       Reduce test burden..          A
                                     reference NFRC 100-   reference NFRC 102-
                                     2010 for              2020 for
                                     determining U-        determining U-
                                     factor as part of     factor and allows
                                     determining energy    AEDMs to be used
                                     consumption.          for determining
                                                           energy consumption.
Doors and Display Panels..........  Uses surface area of  Requires that area    Improve                       A
                                     the door or display   of the aperture or    representative
                                     panel external to     surface area used     values.
                                     the walk-in to        to determine U-
                                     convert U-factor      factor be used to
                                     into a conduction     convert U-factor
                                     load.                 into a conduction
                                                           load.

[[Page 28785]]

 
Doors.............................  Uses a PTO value of   Establishes a PTO     Improve                       A
                                     25 percent for door   value of 97 percent   representative
                                     motors (as they are   specific to door      values and address
                                     considered ``other    motors.               inconsistent values
                                     electricity-                                across waivers
                                     consuming                                   granted.
                                     devices'').
Non-display Doors and Panels......  Incorporates by       Incorporates by       Update applicable             B
                                     reference ASTM C518-  reference ASTM C518-  industry test
                                     04.                   17.                   procedures.
Non-display Doors and Panels......  Does not include      Includes detailed     Ensure test                   B
                                     detailed provisions   provisions for        repeatability.
                                     for determining and   determining and
                                     measuring total       measuring total
                                     insulation            insulation
                                     thickness and test    thickness and test
                                     specimen thickness.   specimen thickness.
Non-display Doors and Panels......  Requires that the     Provides              Ensure test                   B
                                     test specimen meet    specifications for    repeatability.
                                     a parallelism and     determining
                                     flatness tolerance    parallelism and
                                     of 0.03   flatness of the
                                     inches but provides   test specimen.
                                     no guidance on
                                     measurement.
Refrigeration Systems.............  Does not include      Includes guidance on  Ensure test                    C
                                     guidance on test      test room             repeatability.
                                     room conditioning.    conditioning.
Refrigeration Systems.............  Does not include an   Includes an           Reduce test burden..           C
                                     allowance for         allowance for
                                     measuring             measuring
                                     refrigerant           refrigerant
                                     temperatures with     temperatures with
                                     surface-mounted       surface-mounted
                                     measuring             measuring
                                     instruments.          instruments for
                                                           small diameter
                                                           tubes.
Refrigeration Systems.............  Does not include      Includes guidance     Ensure test                    C
                                     guidance for unit     for unit charging     repeatability.
                                     charging or a setup   and a setup
                                     condition hierarchy.  condition hierarchy.
Refrigeration Systems.............  Does not include      Includes provisions   Improve                        C
                                     provisions for        for testing CO2       representative
                                     testing CO2 unit      unit coolers.         values.
                                     coolers.
Refrigeration Systems.............  Does not include      Includes provisions   Improve                        C
                                     provisions for        for testing high-     representative
                                     testing high-         temperature unit      values.
                                     temperature unit      coolers alone.
                                     coolers alone.
Refrigeration Systems.............  Incorporates by       Incorporates by       Update applicable              C1
                                     reference AHRI 1250-  reference AHRI 1250-  industry test
                                     2009, ASHRAE 23.1-    2020, ASHRAE 37-      procedures.
                                     2010, and AHRI 420-   2009, and ASHRAE 16-
                                     2008.                 2016.
Refrigeration Systems.............  Tests single-         Includes multiple     Improve                        C1
                                     packaged dedicated    methods for testing   representative
                                     systems using the     single-packaged       values.
                                     refrigerant           dedicated systems.
                                     enthalpy method for
                                     matched pairs.
Refrigeration Systems.............  Does not include      Includes provisions   Improve                        C1
                                     provisions for        for testing           representative
                                     testing attached      attached split        values.
                                     split systems or      systems or
                                     detachable single-    detachable single-
                                     packaged dedicated    packaged dedicated
                                     systems.              systems.
Refrigeration Systems.............  Does not include      Includes provisions   Improve                        C1
                                     provisions for        for testing multi-    representative
                                     testing multi-        circuit single-       values.
                                     circuit single-       packaged dedicated
                                     packaged dedicated    systems.
                                     systems.
Refrigeration Systems.............  Does not include      Includes provisions   Improve                        C1
                                     provisions for        for testing ducted    representative
                                     testing ducted fan    fan coil units.       values.
                                     coil units.
Refrigeration Systems.............  Does not include      Includes provisions   Improve                        C1
                                     provisions for        for testing high-     representative
                                     testing high-         temperature matched-  values.
                                     temperature matched-  pair and single-
                                     pair and single-      packaged dedicated
                                     packaged dedicated    systems.
                                     systems.
Refrigeration Systems.............  Does not include      Includes provisions   Improve                        C1
                                     provisions for        for testing of        representative
                                     testing of variable-  variable, two-, and   values.
                                      and multiple-        multiple-capacity
                                     capacity dedicated    dedicated
                                     condensing units      condensing units
                                     nor variable- and     and variable, two-,
                                     multiple-capacity     and multiple-
                                     outdoor matched       capacity outdoor
                                     pairs.                matched pairs.
----------------------------------------------------------------------------------------------------------------

    DOE has determined that the amendments described in section III.C 
and III.E of this final rule would not alter the measured energy 
consumption of walk-in doors without motors or the R-value of walk-in 
non-display doors and non-display panels. Therefore, retesting or 
recertification would not be required solely as a result of DOE's 
adoption of the amendments to the test procedures. Additionally, DOE 
has determined that the amendments would not increase the cost of 
testing.
    For walk-in doors with motors, DOE has determined that the 
amendments described in section III of this final rule would either not 
change the measured energy consumption or would result in a lower 
measured energy consumption and therefore, would not require retesting 
or recertification as a result of DOE's adoption of the amendments to 
the test procedures. New testing is only required if the manufacturer 
wishes to make claims using the new, more efficient rating. 
Additionally, DOE has determined the amendments would not increase the 
cost of testing for doors with motors.

[[Page 28786]]

    DOE has also determined that the amendments to appendix C, 
described in section III.F of this final rule would not alter the 
measured efficiency of walk-in refrigeration systems and would not 
require retesting or recertification as a result of DOE's adoption of 
the amendments to the test procedures. Additionally, DOE has determined 
that the amendments would not increase the cost of testing.
    Finally, DOE has determined that the provisions of the new appendix 
C1 described in section III.G of this final rule would alter the 
measured efficiency of walk-in refrigeration systems, in part because 
the amended test procedure adopts a different energy efficiency metric 
than in the current test procedure. However, the use of appendix C1 is 
not required for use until the compliance date of any amended energy 
conservation standards based on the test procedure in appendix C1. 
Additionally, DOE has determined that the provisions in appendix C1 
will increase the cost of testing. DOE's estimation of costs is 
discussed in section III.K of this document.
    The effective date for the amended test procedures adopted in this 
final rule is 30 days after publication of this document in the Federal 
Register. Representations of energy use or energy efficiency must be 
based on testing in accordance with the amended appendices A, B, and C 
test procedures beginning 180 days after the publication of this final 
rule. Manufacturers will be required to certify compliance using the 
new appendix C1 test procedures beginning on the compliance date of any 
final rule establishing amended energy conservation standards for walk-
in refrigeration systems that are published after the effective date of 
this final rule.

III. Discussion

A. Scope and Definitions

    This final rule applies to the test procedures for ``walk-in 
coolers and walk-in freezers.'' The following sections discuss DOE's 
consideration of the scope of the test procedures and relevant 
definitions.
1. Scope
    The following sections discuss considerations and adopted changes 
regarding the scope of equipment covered by DOE's test procedures for 
walk-ins.
a. Liquid-Cooled Refrigeration Systems
    A liquid-cooled refrigeration system rejects heat during the 
condensing process to a liquid, and the liquid transports the heat to a 
remote location. This contrasts with an air-cooled system, which 
rejects heat to ambient air during the condensing process. The current 
DOE test procedure for walk-in refrigeration systems, which 
incorporates by reference AHRI 1250-2009, does not address how to test 
liquid-cooled systems. Additionally, liquid-cooled dedicated condensing 
units are outside the scope of AHRI 1250-2020, being specifically 
excluded in Section 2.2.4. In the April 2022 NOPR, DOE tentatively 
determined that liquid-cooled refrigeration systems represent a small 
portion of the walk-in market, and thus DOE did not propose to amend 
its test procedures to include liquid-cooled refrigeration systems. 87 
FR 23920, 23927.
    In response to the April 2022 NOPR, the Efficiency Advocates and CA 
IOUs encouraged DOE to develop a test procedure for liquid-cooled 
refrigeration systems. (Efficiency Advocates, No. 37 at p. 3; CA IOUs, 
No. 42 at p. 5)
    DOE recognizes the potential benefit of a test procedure for 
liquid-cooled walk-ins and the value that a reliable test procedure can 
provide to facilitate comparable representations of energy use for 
consumers. However, DOE maintains that liquid-cooled refrigeration 
systems represent a small portion of the walk-in market, and the 
potential for energy savings that could be realized through the 
development of a test procedure and corresponding energy conservation 
standards is likely limited at this time. Additionally, DOE is not 
aware of an industry test standard for liquid cooled walk-in 
refrigeration systems. Therefore, although liquid-cooled refrigeration 
systems are covered within the scope of the walk-in coolers and walk-in 
freezers definition, DOE is not adopting provisions specific to liquid-
cooled refrigeration systems in its test procedure at this time.
b. Carbon Dioxide Systems
    Currently, the DOE test procedure for walk-in refrigeration systems 
does not explicitly define scope based on refrigerant. See 10 CFR 
431.301 and 431.304 and appendix C. DOE understands that the current 
test procedure, which is based on AHRI 1250-2009 (incorporated by 
reference, 10 CFR 431.303(b)), specifies test conditions that may not 
be consistent with the design and operation of carbon dioxide 
(``CO2'') refrigeration systems (i.e., although AHRI 1250-
2009 does not specifically exclude CO2 systems, the test 
method is not designed to accommodate such systems).\14\
---------------------------------------------------------------------------

    \14\ The DOE test procedure for unit coolers requires testing 
with a liquid inlet saturation temperature of 105 [deg]F and a 
liquid inlet subcooling temperature of 9 [deg]F, as specified by 
Tables 15 and 16 of AHRI 1250-2009. However, CO2 has a 
critical temperature of 87.8 [deg]F; therefore, it does not coexist 
as saturated liquid and gas above this temperature. The liquid inlet 
saturation temperature of 105 [deg]F and the liquid inlet subcooling 
temperature of 9 [deg]F specified in appendix C, are not achievable 
by CO2 unit coolers.
---------------------------------------------------------------------------

    As a result, DOE has granted waivers or interim waivers to 
manufacturers from appendix C, for specific basic models of 
CO2 unit coolers.\15\ The alternate test procedure granted 
in these waivers and DOE's amendments with respect to refrigeration 
systems utilizing CO2 as a refrigerant are further discussed 
in section III.F.6 of this document.
---------------------------------------------------------------------------

    \15\ HTPG Decision and Order, 86 FR 14887 (Mar. 19, 2021); 
Hussmann Decision and Order, 86 FR 24606 (May 7, 2021); KeepRite 
Decision and Order, 86 FR 24603 (May 7, 2021); RefPlus Interim 
Waiver, 86 FR 43633 (Aug. 10, 2021).
---------------------------------------------------------------------------

    In the April 2022 NOPR, DOE tentatively determined that walk-in 
refrigeration equipment utilizing CO2 as a refrigerant meets 
the definition of a walk-in refrigeration system. In the April 2022 
NOPR, DOE proposed test procedure provisions specific to (1) single-
packaged dedicated systems and (2) unit cooler variants of 
CO2 refrigeration systems. DOE did not propose test 
procedure provisions specific to CO2-dedicated condensing 
units.\16\
---------------------------------------------------------------------------

    \16\ As discussed in the April 2022 NOPR, DOE preliminarily 
found that, in the North American market, CO2 is 
primarily used in large rack systems, and there do not appear to be 
any CO2 dedicated condensing units available. Hence, DOE 
tentatively found that adopting a test procedure for CO2 
dedicated condensing units is currently not warranted. 87 FR 23920, 
23928.
---------------------------------------------------------------------------

    In response to the April 2022 NOPR, the CA IOUs and HTPG stated 
that CO2-dedicated condensing units are available on the 
market in the United States. (CA IOUs, No. 42 at p. 4; HTPG, No. 32 at 
p. 2) The CA IOUs, HTPG, and the Efficiency Advocates encouraged DOE to 
develop a test procedure for CO2-dedicated condensing units. 
(CA IOUs, No. 42 at p. 4; HTPG, No. 32 at p. 2; Efficiency Advocates, 
No. 37 at p. 2)
    DOE has conducted additional market research and determined that 
while CO2 dedicated condensing units are currently available 
in the United States the market is small. In addition, due to COVID 
supply constraints, DOE has not been able to procure a CO2 
dedicated condensing unit to evaluate for testing. Therefore, DOE is 
not adopting a test procedure for CO2 dedicated condensing 
units at this time. The test procedures for CO2 unit coolers 
and single-packaged dedicated systems that use CO2 as a 
refrigerant are discussed in

[[Page 28787]]

more detail in sections III.F.6 and III.G.2.g of this document, 
respectively.
c. Multi-Circuit Single-Packaged Dedicated Systems
    DOE published an interim test procedure waiver for Refrigerated 
Solutions Group (RSG) on July 22, 2022. 87 FR 43808. In its petition 
for waiver and interim waiver, RSG stated that the current walk-in test 
procedure does not address multiple refrigeration circuits enclosed in 
a single unit. DOE has determined that refrigeration systems with 
multiple refrigeration circuits that share a single evaporator and a 
single condenser and that are used in walk-in applications meet the 
definition of ``walk-in cooler and walk-in freezer.'' Thus, DOE is 
adding a definition for ``multi-circuit single-packaged dedicated 
system,'' as discussed in section III.A.2.e of this document, and 
adopting a test procedure for such systems, as discussed in section 
III.G.2.f of this document.
d. Ducted Units
    As discussed in the April 2022 NOPR, DOE is aware that some walk-in 
evaporators and/or dedicated condensing units are sold with provisions 
to be installed with ducting to circulate air between the walk-in and 
the refrigeration system; however, unit cooler and single-packaged 
systems sold for ducted installation are not addressed by either the 
definition for ``single-packaged dedicated system'' or ``unit cooler.'' 
87 FR 23920, 23928. The current definition of ``single-packaged 
dedicated system'' specifies that such systems do not have ``any 
element external to the system imposing resistance to flow of the 
refrigerated air,'' and the definition of ``unit cooler'' specifies 
that such equipment does not have ``any element external to the cooler 
imposing air resistance.'' 10 CFR 431.302. As such, unit coolers and 
single-packaged dedicated systems sold for ducted installation are not 
addressed by either definition. In addition, the current test procedure 
does not include provisions for the setup of ductwork. While the 
definition of ``condensing unit'' does not exclude systems intended for 
ducted installation, the current test procedure also does not include 
provisions for setup of ductwork for these components.
    DOE has granted waivers from the test procedure in appendix C, to 
CellarPro, Air Innovations, Vinotheque, and Vinotemp, and an interim 
waiver to LRC Coil, for walk-ins marketed for use as wine cellar 
refrigeration systems.\17\ Relevant to the present discussion of scope, 
the specific basic models for which waivers have been granted include 
equipment sold as ducted units.
---------------------------------------------------------------------------

    \17\ CellarPro Decision and Order, 86 FR 26496 (May 14, 2021); 
Air Innovations Decision and Order, 86 FR 23702 (May 4, 2021); 
Vinotheque Decision and Order, 86 FR 26504 (May 14, 2021); Vinotemp 
Decision and Order, 86 FR 36732 (July 13, 2021); LRC Coil Interim 
Waiver, 86 FR 47631 (Aug. 26, 2021).
---------------------------------------------------------------------------

    In this final rule, DOE is revising the single-packaged dedicated 
system definition to clarify that such systems may have provisions for 
ducted installation. DOE is adding a definition for ``ducted fan coil 
unit,'' the ducted equivalent of a unit cooler, as discussed in section 
III.A.2.d of this document. In doing so, DOE preserves the industry 
standard definition of a unit cooler while expanding the scope of the 
test procedure to ducted units. DOE is also adding provisions in the 
test procedures to address setup of ductwork and the external static 
pressure that it imposes on refrigeration system fans--all to improve 
the representativeness of the test procedure for ducted units. These 
test procedure revisions are addressed in section III.G.6 of this 
document.
2. Definitions
a. Walk-In Cooler and Walk-In Freezer
    DOE currently defines the term ``walk-in cooler and walk-in 
freezer'' as an enclosed storage space refrigerated to temperatures, 
respectively, above, and at or below 32 degrees Fahrenheit, that can be 
walked into, and has a total chilled storage area of less than 3,000 
square feet; however, the term does not include products designed and 
marketed exclusively for medical, scientific, or research purposes. 10 
CFR 431.302. (See also 42 U.S.C. 6311(20))
    To align the definition of walk-in cooler and walk-in freezer with 
the regulatory scheme adopted by DOE--which establishes separate test 
procedures and energy conservation standards for the principal 
components that make up a walk-in: panels, doors, and refrigeration 
systems--in the April 2022 NOPR, DOE proposed to amend the definition 
to specify that a walk-in may comprise these principal components. DOE 
requested comment on this proposed change. 87 FR 23920, 23928.
    AHRI, Anthony, RSG, HTPG, KeepRite, Lennox, and National 
Refrigeration agreed with DOE's proposed changes to the definition of 
walk-in cooler and walk-in freezer. (AHRI, No. 30 at p. 2; Anthony, No. 
31 at p. 1; RSG, No. 41 at p. 1; HTPG, No. 32 at p. 2; KeepRite, No. 36 
at p. 1; Lennox, No. 35 at p. 2; National Refrigeration, No. 39 at p. 
1) For the reasons discussed in the previous paragraph and the April 
2022 NOPR, DOE is adopting the definition proposed in the April 2022 
NOPR that ``walk-in cooler and walk-in freezer'' means an enclosed 
storage space, including but not limited to panels, doors, and 
refrigeration systems, refrigerated to temperatures, respectively, 
above, and at or below 32 degrees Fahrenheit that can be walked into, 
and has a total chilled storage area of less than 3,000 square feet; 
however, the terms do not include products designed and marketed 
exclusively for medical, scientific, or research purposes.
    The Efficiency Advocates commented that refrigerated shipping 
containers should be within the scope of the walk-in test procedures. 
(Efficiency Advocates, No. 37 at p. 4) DOE notes that based on its 
initial research, neither the previous definition of walk-in cooler and 
walk-in freezer nor the amended definition adopted in this final rule 
would specifically exclude refrigerated shipping containers. However, 
DOE has not evaluated refrigerated shipping containers to determine if 
current walk-in test procedures would produce test results that reflect 
energy efficiency, energy use, or estimated operating costs during a 
representative average use cycle, without being unduly burdensome to 
conduct. Therefore, DOE has determined that refrigerated shipping 
containers are not currently subject to the DOE test procedure or 
energy conservation standards for WICFs. DOE may consider whether test 
procedures and energy conservation standards should be applied to 
refrigerated shipping containers in future rulemakings.
b. Doors
    With respect to walk-ins, DOE defines a ``door'' as an assembly 
installed in an opening on an interior or exterior wall that is used to 
allow access or close off the opening and that is movable in a sliding, 
pivoting, hinged, or revolving manner of movement. For walk-in coolers 
and walk-in freezers, a door includes the door panel, glass, framing 
materials, door plug, mullions, and any other elements that form the 
door or part of its connection to the wall. 10 CFR 431.302.
(1) Door, Door Leaf, and Door Plug
    In the April 2022 NOPR, DOE discussed that the current definition 
of ``door'' does not explicitly address that walk-in door assemblies 
may contain multiple door openings within one frame. 87 FR 23920, 
23929. DOE also

[[Page 28788]]

noted that NFRC 100-2010 includes several defined terms relating to 
door components (e.g., door leaf), which differ from the terms used in 
DOE's definition of ``door.'' Id. Additionally, certain stakeholders 
commented that they are unfamiliar with the term ``door plug,'' whereas 
others used it to describe different components of the door assembly. 
Id.\18\
---------------------------------------------------------------------------

    \18\ In response to the June 2021 RFI, Anthony and AHRI stated 
that they were unfamiliar with the term ``door plug.'' (Anthony, No. 
8 at pp. 1-2; AHRI, No. 11 at pp. 2-3) In response to the June 2021 
RFI, Imperial Brown and Hussmann commented that they used the term 
``door plug'' to describe different components of the door assembly. 
(Imperial Brown, No. 15 at p. 1; Hussmann, No. 18 at p. 3)
---------------------------------------------------------------------------

    In the April 2022 NOPR, DOE proposed to amend the definition of 
``door'' to address doors with multiple openings within one frame, to 
include terminology that generally aligns with that used by the 
industry, and to remove use of the term ``door plug.'' Id. 
Specifically, DOE proposed to define ``door'' as an assembly installed 
in an opening on an interior or exterior wall that is used to allow 
access or close off the opening and that is movable in a sliding, 
pivoting, hinged, or revolving manner of movement. For walk-in coolers 
and walk-in freezers, a door includes the frame (including mullions), 
the door leaf or multiple door leaves (including glass) within the 
frame, and any other elements that form the assembly or part of its 
connection to the wall. DOE also proposed to define the term ``door 
leaf'' to mean the pivoting, rolling, sliding, or swinging portion of a 
door. Id.
    Regarding the proposed definition of ``door,'' Senneca considered 
the proposed definition of ``door'' to refer to the door system (i.e., 
includes the door leaf, frame, casings, header, tracks, and all 
necessary components and hardware). (Senneca, No. 26 at p. 1) AHRI 
commented that its members find DOE's current definition unclear and 
recommended that DOE not use what AHRI referred to as the ``single 
door'' interpretation. (AHRI, No. 30 at p. 2) DOE interprets AHRI's 
comment to mean that a door with multiple openings within a single 
frame should not be treated as a single basic model. DOE notes that the 
proposed definition of ``door'' is consistent with Senneca's 
understanding. Additionally, DOE notes that the proposed definition 
intends to clarify the definition of ``door'', particularly, that a 
``door'' consists of a single frame and includes all parts of the door 
assembly attached to the single frame, including multiple door openings 
where applicable.
    Anthony stated that the definition of ``door'' does not accurately 
reflect the use of the term ``door'' in the 2014 final rule engineering 
analysis spreadsheet.\19\ (Anthony, No. 31 at pp. 1-3) Specifically, 
Anthony commented that when applying the same formula to a single door 
with multiple openings, there is a 20 to 30 percent reduction in energy 
allowance per door. Id. DOE notes that this comment refers to the 
representative units used to evaluate and adopt energy conservation 
standards in a final rule published on June 3, 2014 (79 FR 32050). DOE 
has determined that the representative units used in 2014 met the 
definition of ``door'' at the time of the analysis and would continue 
to meet the definition of ``door'' as amended by this final rule.-- The 
amended definition of ``door'' adopted in this final rule provides 
additional clarity that a door contains a single frame with one or 
multiple door openings. Regarding the energy impacts of doors with 
multiple openings, DOE recommends that stakeholders provide feedback on 
the representative unit characteristics in response to the ongoing 
energy conservation standards rulemaking which is the appropriate venue 
to address such concerns (see docket EERE-2017-BT-STD-0009).
---------------------------------------------------------------------------

    \19\ Anthony is referring to the engineering analysis for 
display doors as part of the June 2014 ECS Final Rule, which can be 
found at regulations.gov under docket number EERE-2008-BT-STD-0015-
0084.
---------------------------------------------------------------------------

    For the reasons discussed in the preceding paragraphs and the April 
2022 NOPR, this final rule adopts the revised definition of ``door'' as 
proposed.
    Bally agreed with the term ``door leaf'' and stated that the term 
as defined would be easily understood. (Bally, No. 40 at p. 1) AHRI 
stated that DOE's proposed definition of ``door leaf'' is clear. (AHRI, 
No. 30 at p. 2) Senneca commented that it considers ``door leaf'' to be 
a movable, insulated portion of the assembly. (Senneca, No. 26 at p. 
10) DOE has concluded that Senneca's comment is consistent with the 
proposed definition of ``door leaf.'' This final rule adopts the 
definition of ``door leaf'' as proposed in the April 2022 NOPR. 87 FR 
23920, 23929.
    DOE did not receive any comments regarding its proposal to remove 
use of the term ``door plug.'' For the reasons discussed in the April 
2022 NOPR, this final rule removes the term ``door plug'' as proposed. 
Id.
(2) Non-Display Door
    DOE also proposed to define the term ``non-display door'' in the 
April 2022 NOPR. 87 FR 23920, 23930. Although the test procedures 
outlined in 10 CFR 431.304 and appendices A and B use the term ``non-
display door,'' it is not currently defined. DOE proposed to define a 
``non-display door'' as a door that is not a display door.\20\
---------------------------------------------------------------------------

    \20\ DOE defines ``display door'' as a door that (1) is designed 
for product display; or (2) has 75 percent or more of its surface 
area composed of glass or another transparent material. 10 CFR 
431.302.
---------------------------------------------------------------------------

    In response to the April 2022 NOPR discussion of non-display doors, 
Hussmann stated that although its Heavy Duty Door products and ABC Beer 
Cave sliding door products are made largely of glass, it does not 
believe these doors meet the display door definition because they are 
designed to be used as passage doors (i.e., passage of people). 
(Hussmann, No. 34 at p. 2) In response, DOE notes that the display door 
definition references the physical characteristics of the door (i.e., 
the portion of surface area composed of glass or another transparent 
material), and is not contingent on door application. Any door(s) that 
meets this criteria is considered a display door, even those not 
necessarily designed for product display.
    In this final rule, DOE is adopting the definition of ``non-display 
door'' as proposed in the April 2022 NOPR.
(3) Hinged Vertical Door, Roll-Up Door, and Sliding Door
    In the April 2022 NOPR, DOE tentatively determined that 
differentiating walk-in doors based on opening characteristics would 
better align with industry terminology and proposed to define three 
terms to further differentiate all walk-in doors (including both 
display and non-display doors): ``hinged vertical door,'' ``roll-up 
door,'' and ``sliding door.'' 87 FR 23920, 23930.
    DOE proposed to define ``hinged vertical door'' as a door with a 
door leaf (or leaves) with a hinge (or hinges) connecting one vertical 
edge of the door leaf (or leaves) to a frame or mullion of the door. 
This includes doors that swing open in one direction (i.e., into or out 
of the walk-in) and free-swinging doors that open both into and out of 
the walk-in. 87 FR 23920, 23991.
    DOE proposed to define ``roll-up door'' as a door that bi-
directionally rolls open and closed in a vertical and horizontal manner 
and may include vertical jamb tracks. Id.
    DOE proposed to define ``sliding door'' as a door having one or 
more manually operated or motorized door leaves within a common frame 
that slide horizontally or vertically. Id.

[[Page 28789]]

    In the April 2022 NOPR, DOE requested feedback on the proposed 
definitions for ``hinged vertical door,'' ``roll-up door,'' and 
``sliding door.'' Id. Senneca and AHRI agreed with DOE's proposed 
definitions. (Senneca, No. 26 at p. 1; AHRI, No. 30 at p. 2)
    DOE recognizes that these definitions are not used in the adopted 
test procedure amendments. In the preliminary analysis for the walk-in 
standards energy conservation rulemaking, DOE stated that it was 
interested in differentiating its analysis by door opening 
characteristics. See page ES-36 of the preliminary analysis technical 
support document (EERE-2017-BT-STD-0009-0024). DOE is not adopting 
definitions for the terms ``hinged vertical door,'' ``roll-up door,'' 
and ``sliding door'' and will consider the potential adoption of these 
terms in the ongoing energy conservation standards rulemaking for 
WICFs.
    As discussed in the April 2022 NOPR, DOE currently differentiates 
non-display doors by whether they are passage doors or freight doors. 
87 FR 23920, 23929. A ``freight door'' is a door that is not a display 
door and is equal to or larger than 4 feet wide and 8 feet tall. 10 CFR 
431.302. A ``passage door'' is a door that is not a freight or display 
door. Id. After reviewing comments submitted in response to the June 
2021 RFI, DOE did not propose to amend the definition of freight door 
or passage door. DOE again received comments, however, on the 
definitions of freight and passage doors. 87 FR 23920, 23930.
    Bally commented that specifying the way a door leaf is moved would 
not aid in defining a door nor clarify whether a non-display door is a 
passage or a freight door. (Bally, No. 40 at p. 1) Additionally, Bally 
disagreed with the current distinction of freight doors by size, 
stating that it manufactures doors with a width greater than or equal 
to 4 feet that are often the only door in the WICF; therefore, it 
considers these doors to be passage doors rather than freight doors. 
Id. Senneca stated that it views opening size as a determinant to 
whether a non-display door is designated as a passage or freight door 
and reiterated that a freight door has a width-in clear \21\ (``WIC'') 
greater than or equal to 4 feet and a height-in-clear \22\ (``HIC'') 
greater than or equal to 8 feet. (Senneca, No. 26 at p. 1)
---------------------------------------------------------------------------

    \21\ In their comment in response to the June 2021 RFI, Imperial 
Brown defined WIC as the clear opening width, typically from left 
frame jamb to right frame jamb. See EERE-2017-BT-TP-0010-0015 at p. 
1.
    \22\ In their comment in response to the June 2021 RFI, Imperial 
Brown defined HIC as the clear opening height, typically from door 
sill to frame header. See EERE-2017-BT-TP-0010-0015 at p. 1.
---------------------------------------------------------------------------

    DOE acknowledges that stakeholder comments demonstrate that factors 
other than size may be used to differentiate between a passage and 
freight door. However, DOE concludes that size is currently the most 
suitable way to differentiate between a passage door and a freight 
door. Therefore, DOE is not amending these definitions.
c. High-Temperature Refrigeration System
    As mentioned previously, DOE has granted several manufacturers 
waivers and interim waivers from the current test procedure in appendix 
C for basic models of refrigeration systems marketed as wine cellar 
refrigeration systems (see section III.A.1.d of this document). These 
manufacturers stated that walk-ins used for wine storage are intended 
to operate at a temperature range of 45 to 65 [deg]F and 50 to 70 
percent relative humidity, rather than the 35 [deg]F and less than 50 
percent relative humidity test conditions prescribed in appendix C.
    In the April 2022 NOPR, DOE proposed to define ``high-temperature 
refrigeration system'' as a walk-in refrigeration system that is not 
designed to operate below 45 [deg]F. 87 FR 23920, 23930. DOE did not 
receive any feedback from stakeholders on the proposed definition; 
however, the CA IOUs commented that they support DOE including a test 
method for high-temperature unit coolers (CA IOUs, No. 42 at p. 6). DOE 
is adopting the definition for ``high-temperature refrigeration 
system'' as proposed in the April 2022 NOPR. Section III.G.6 provides 
further details of the corresponding test procedure provisions.
d. Ducted Fan Coil Unit and Ducted Single-Packaged Dedicated System
    As discussed in the April 2022 NOPR, the definitions for single-
packaged dedicated systems and unit coolers currently exclude ducted 
units. 87 FR 23920, 23931. As a part of the high-temperature 
refrigeration system waivers discussed in section III.A.2.c, DOE has 
granted waivers to Air Innovations, Vinotheque, CellarPro, and 
Vinotemp, and an interim waiver to LRC Coil, for walk-ins that are 
marketed as wine cellar refrigeration systems that are designed and 
marketed as ducted units.
    To clarify that refrigeration systems with provision for ducted 
installation are included in the DOE test procedure, DOE proposed to 
adopt the new term ``ducted fan-coil unit,'' defined as an assembly 
including means for forced air circulation capable of moving air 
against both internal and non-zero external flow resistance and 
elements by which heat is transferred from air to refrigerant to cool 
the air, with provision for ducted installation. 87 FR 23920, 23931. 
DOE also proposed to revise the current ``single-packaged dedicated 
system'' definition to mean a refrigeration system (as defined in 10 
CFR 431.302) that is a single-packaged assembly that includes one or 
more compressors, a condenser, a means for forced circulation of 
refrigerated air, and elements by which heat is transferred from air to 
refrigerant. Id.
    In the April 2022 NOPR, DOE requested comment on its proposed 
definition for ``ducted fan coil unit'' and on the proposed 
modification to the definition of ``single-packaged dedicated system.'' 
Id. RSG agreed with the proposed definitions. (RSG, No. 41 at p. 1) 
AHRI and HTPG suggested separate definitions for ducted and non-ducted 
single-packaged dedicated systems. (AHRI, No. 30 at pp. 2-3; HTPG, No. 
32 at p. 2)
    After consideration of stakeholder comments, and to maintain 
consistency with industry terminology, DOE is adopting a separate 
definition for ``ducted single-packaged dedicated system'' that means a 
refrigeration system (as defined in 10 CFR 431.302) that is a single-
packaged assembly designed for use with ducts, that includes one or 
more compressors, a condenser, a means for forced circulation of 
refrigerated air, and elements by which heat is transferred from air to 
refrigerant. As such, DOE is maintaining its current definition of a 
``single-packaged dedicated system,'' and clarifying that it describes 
non-ducted units.
    DOE received no feedback from stakeholders on the proposed 
definition for the new term ``ducted fan coil unit.'' DOE is adopting 
the definition for ``ducted fan coil unit'' as proposed in the April 
2022 NOPR.
e. Multi-Circuit Single-Packaged Dedicated System
    In the April 2022 NOPR, DOE proposed to define a ``multi-circuit 
single-packaged dedicated system'' as a single-packaged dedicated 
system (as defined in 10 CFR 431.302) that contains two or more 
refrigeration circuits that refrigerate a single stream of circulated 
air. DOE requested comment on this proposed definition. 87 FR 23920, 
23931.
    RSG agreed with the proposed definition. (RSG, No. 41 at p. 1) AHRI 
and HTPG suggested that the proposed definition is too specific and 
should be

[[Page 28790]]

broader. (AHRI, No. 30 at p. 3; HTPG, No. 32 at p. 3) However, AHRI and 
HTPG did not provide alternative definitions or other additional 
information that might support broadening the definition.
    In this final rule, DOE is adopting the definition for ``multi-
circuit single-packaged dedicated refrigeration system'' as proposed in 
the April 2022 NOPR.
    As discussed in section III.A.2.d, DOE proposed to adopt the new 
term ``ducted fan-coil unit'' to clarify that refrigeration systems 
with provision for ducted installation are included in the DOE test 
procedure. 87 FR 23920, 23931. In response to the April 2022 NOPR, 
several stakeholders suggested creating separate definitions for ducted 
and non-ducted single-packaged dedicated systems. (AHRI, No. 30 at pp. 
2-3; HTPG, No. 32 at p. 2) DOE's current definition for a ``single-
packaged dedicated system'' applies only to non-ducted units. As 
discussed in section III.A.2.d, after consideration of stakeholder 
comments, and to maintain consistency with industry terminology, DOE is 
adopting a definition for ducted single-packaged dedicated systems 
Since ducted multi-circuit single-packaged dedicated systems are a 
derivative of ducted single-packaged dedicated systems, DOE is also 
defining ``ducted multi-circuit single-packaged dedicated systems'' to 
mean a ducted single-packaged dedicated system that contains two or 
more refrigeration circuits that refrigerate a single stream of 
circulated air. DOE believes these amendments are consistent with the 
intent of proposed changes in the April 2022 NOPR while being 
responsive to stakeholder feedback.
f. Attached Split System
    As discussed in the April 2022 NOPR, DOE is aware of some 
refrigeration systems that are sold as matched pairs in which the 
dedicated condensing unit and unit cooler are permanently attached to 
each other with structural beams. 87 FR 23920, 23931. The DOE test 
procedure does not currently define such systems, nor does it provide 
any unique test provisions for them, thereby affecting the ability of 
manufacturers to provide test results reflecting the energy efficiency 
of this equipment during a representative average use cycle. DOE 
proposed to define ``attached split system'' as a matched-pair 
refrigeration system designed to be installed with the evaporator 
entirely inside the walk-in enclosure and the condenser entirely 
outside the walk-in enclosure, and the evaporator and condenser are 
permanently connected with structural members extending through the 
walk-in wall. Id.
    In the April 2022 NOPR, DOE requested comment on the proposed 
definition for ``attached split system.'' Id. AHRI, HTPG, Hussmann, and 
Lennox agreed with the proposed definition. (AHRI, No. 30 at p. 3; 
HTPG, No. 32 at p. 3; Hussmann, No. 38 at p. 2; Lennox, No. 35 at p. 2)
    In this final rule, DOE is adopting the proposed definition for 
``attached split system.'' The provisions for testing such units are 
discussed in section III.G.4 of this document.
g. Detachable Single-Packaged System
    As discussed in the April 2022 NOPR, DOE had tentatively determined 
that detachable single-packaged systems are a type of single-packaged 
dedicated system, and proposed to define ``detachable single-packaged 
system'' as a system consisting of a dedicated condensing unit and an 
insulated evaporator section in which the evaporator section is 
designed to be installed external to the walk-in enclosure and 
circulating air through the enclosure wall, and the condensing unit is 
designed to be installed either attached to the evaporator section or 
mounted remotely with a set of refrigerant lines connecting the two 
components. 87 FR 23920, 23931. The current DOE test procedure does not 
define such systems or provide testing provisions specific to this 
configuration.
    In the April 2022 NOPR, DOE requested comment on the proposed 
definition for ``detachable single-packaged dedicated system.'' Id. 
AHRI, HTPG, Lennox, and RSG agreed with the proposed definition. (AHRI, 
No. 30 at p. 3; HTPG, No. 32 at p. 3; Lennox, No. 35 at p. 2; RSG, No. 
41 at p. 1)
    In this final rule, DOE is adopting the definition for ``detachable 
single-packaged dedicated system'' as proposed in the April 2022 NOPR.
h. CO2 Unit Cooler
    In the April 2022 NOPR, DOE proposed a test procedure for 
CO2 unit coolers. 87 FR 23920, 23952. To clarify the scope 
of the proposed CO2 unit cooler test procedure, DOE proposed 
to define a ``CO2 unit cooler'' as one that includes a 
nameplate listing only CO2 as an approved refrigerant. 87 FR 
23920, 23932.
    In the April 2022 NOPR, DOE requested comment on the proposed 
definition of CO2 unit coolers. Id. AHRI, HTPG, Hussmann, 
Lennox, National Refrigeration, and RSG agreed with the proposed 
definition. (AHRI, No. 30 at p. 3; HTPG, No. 32 at p. 3; Hussmann, No. 
38 at p. 2; Lennox, No. 35 at p. 2; National Refrigeration, No. 39 at 
p. 1; RSG, No. 41 at p. 1)
    DOE also requested comment on whether any distinguishing features 
of CO2 unit coolers exist that could reliably be used as an 
alternative approach to differentiate them from those unit coolers 
intended for use with conventional refrigerants. 87 FR 23920, 23932.
    AHRI, HTPG, Lennox, and National Refrigeration all stated that they 
were not aware of any features that distinguish CO2 unit 
coolers from those that use traditional refrigerants. (AHRI, No. 30 at 
p. 3; HTPG, No. 32 at p. 3; Lennox, No. 35 at p. 2; National 
Refrigeration, No. 39 at p. 1)
    Given that stakeholders are not aware of any features that 
distinguish CO2 unit coolers from those that use traditional 
refrigerants, this information must be provided on the unit in some 
way. Therefore, DOE is adopting the ``CO2 unit cooler'' 
definition proposed in the April 2022 NOPR which requires a nameplate 
listing only CO2 as an approved refrigerant for this 
equipment.
i. Hot Gas Defrost
    In the April 2022 NOPR, DOE proposed that manufacturers of 
equipment with hot gas defrost installed at the factory may make market 
representations of performance with hot gas defrost activated, in 
addition to the current required calculation-based approach using 
default electric defrost parameters, and proposed a definition for 
``hot gas defrost'' to clarify the scope of the voluntary 
representation. 87 FR 23920, 23932.
    AHRI, HTPG, KeepRite, Lennox, National Refrigeration, and RSG all 
recommended changes to the definition as proposed. (AHRI, No. 30 at p. 
3; HTPG, No. 32 at p. 3; KeepRite, No. 36 at p. 1; Lennox, No. 35 at p. 
2; National Refrigeration, No. 39 at p. 1; RSG, No. 41 at p. 4) In 
particular, AHRI, HTPG, and Lennox stated that not all hot gas defrost 
systems are factory installed. (AHRI, No. 30 at pp. 3-4; HTPG, No. 32 
at p. 3; Lennox, No. 35 at p. 2)
    DOE intended for the voluntary hot gas defrost representation 
provisions proposed in the April 2022 NOPR to apply only to factory-
installed hot gas defrost systems. 87 FR 23920, 23970. Considering the 
comments received, DOE recognizes that the proposed provisions would 
not apply to many hot gas defrost applications, thus negating the 
purpose and intent of DOE's proposal. Therefore, DOE has determined not 
to adopt provisions allowing representations of performance with hot 
gas defrost activated at this

[[Page 28791]]

time and consequently is not adopting a definition for ``hot gas 
defrost.''

B. Updates to Industry Standards

    The current DOE test procedures for walk-in coolers and freezers 
incorporate the following industry test standards: NFRC 100-2010 into 
appendix A; ASTM C518-04 into appendix B; and AHRI 1250-2009, AHRI 420-
2008,\23\ and ASHRAE 23.1-2010 \24\ into appendix C. The following 
sections discuss the industry standards DOE is incorporating by 
reference in this final rule and the relevant provisions of those 
industry standards that DOE is adopting.
---------------------------------------------------------------------------

    \23\ AHRI 420-2008, ``Performance Rating of Forced-Circulation 
Free-Delivery Unit Coolers for Refrigeration'' (``AHRI 420-2008'').
    \24\ ANSI/ASHRAE 23.1-2010, ``Methods of Testing for Rating the 
Performance of Positive Displacement Refrigerant Compressors and 
Condensing Units that Operate at Subcritical Temperatures of the 
Refrigerant'' (``ASHRAE 23.1-2010'').
---------------------------------------------------------------------------

1. Industry Standards for Determining Thermal Transmittance (U-Factor)
    As discussed in the April 2022 NOPR, appendix A to subpart R of 
part 431 references NFRC 100-2010 as the method for determining the U-
factor of doors and display panels, which references NFRC 102-2010. 87 
FR 23920, 23932. NFRC has published updates to NFRC 102-2010, the most 
recent being NFRC 102-2020, which contains the following substantive 
changes from NFRC 102-2010:
    1. Added a list of required calibrations for primary measurement 
equipment;
    2. Added metering box wall transducer and surround panel flanking 
loss characterization and annual verification procedure;
    3. Incorporated a calibration transfer standard continuous 
characterization procedure; and
    4. Revised the provisions regarding air velocity distribution to be 
more specific to the type of fans used.
    DOE proposed to adopt by reference in appendix A the following 
sections of NFRC 102-2020 in place of NFRC 100-2010 for determining U-
factor:

 2. Referenced Documents
 3. Terminology
 5. Apparatus
 6. Calibration
 7. Experimental Procedure (excluding 7.3. Test Conditions)
 8. Calculation of Thermal Transmittance
 9. Calculation of Standardized Thermal Transmittance
 Annex A1. Calibration Transfer Standard Design
 Annex A2. Radiation Heat Transfer Calculation Procedure
 Annex A4. Garage Panel and Rolling Door Installation

87 FR 23920, 23932.
    DOE also proposed to incorporate by reference ASTM C1199-14, as it 
is referenced in NFRC 102-2020. Specifically, in the appendix A test 
procedure, DOE proposed to reference the following sections of ASTM 
C1199-14 as referenced through NFRC 102-2020: sections 2, 3, 5, 6, 7 
(excluding 7.3), 8, 9, and annexes A1 and A2. DOE did not propose to 
reference any other sections of NFRC 102-2020 or ASTM C1199-14, as 
either they do not apply or they are in direct conflict with other test 
procedure provisions included in appendix A.
    In this final rule, DOE is incorporating by reference NFRC 102-2020 
and ASTM C1199-14 in appendix A as proposed in the April 2020 NOPR. DOE 
further discusses the reference to NFRC 102-2020 in place of NFRC 100-
2010 and addresses stakeholder comments in section III.C.1 of this 
document.
2. Industry Standard for Determining R-Value
    As discussed in the April 2022 NOPR, section 4.2 of appendix B to 
subpart R of part 431 references ASTM C518-04 \25\ to determine the 
thermal conductivity, or K-factor, of panel insulation. 87 FR 23920, 
23932. ASTM published a revision of ASTM C518 in July 2017 (``ASTM 
C518-17''). Id.
---------------------------------------------------------------------------

    \25\ ASTM C518-04 is the version of the industry test procedure 
specified by EPCA as the basis for calculating the K-factor.
---------------------------------------------------------------------------

    In the April 2022 NOPR, DOE tentatively determined that the updates 
in ASTM C518-17 do not substantively change the test method and do not 
impact test burden compared to ASTM C518-04. Therefore, DOE proposed to 
amend its test procedure for determining insulation R-value for non-
display doors and panels by incorporating by reference ASTM C518-17. 
Specifically, in the test procedure in appendix B, DOE proposed to 
reference the following sections of ASTM C518-17:

 2. Referenced Documents
 3. Terminology
 5. Apparatus
 6. Calibration
 7. Test Procedures (excluding 7.3. Specimen Conditioning)
 8. Calculation
 Annex A1. Equipment Design

87 FR 23920, 23933.
    DOE did not propose to reference any other sections of ASTM C518-
17, as either they do not apply or they are in direct conflict with 
other test procedure provisions included in appendix B. Because ASTM 
C518-17 is an updated version of ASTM C518-04, DOE stated in the April 
2022 NOPR that the test procedure for determining the K-factor would 
effectively remain based on ASTM C518-04 as specified by EPCA (42 
U.S.C. 6314(a)(9)(A)(ii)).
    In response to the April 2022 NOPR, Anthony supported the proposal 
to reference the latest version of the industry test procedure, ASTM 
C518-17. (Anthony, No. 31 at p. 3)
    In this final rule, DOE is incorporating by reference the sections 
of ASTM C518-17 as proposed in the April 2022 NOPR.
3. Industry Standards for Determining AWEF
    DOE's current test procedure for WICF refrigeration systems is 
codified in appendix C to subpart R of part 431 and incorporates by 
reference AHRI 1250-2009, AHRI 420-2008, and ASHRAE 23.1-2010. AHRI 
1250-2009 is the industry test standard for walk-in cooler and freezer 
refrigeration systems, including unit coolers and dedicated condensing 
units sold separately, as well as matched pairs. 81 FR 95758, 
95798.\26\ The procedure describes the method for measuring the 
refrigeration capacity and the electrical energy consumption for a 
condensing unit and a unit cooler, including off-cycle fan and defrost 
subsystem contributions. Using the refrigeration capacity and 
electrical energy consumption, AHRI 1250-2009 provides a calculation 
methodology to compute AWEF, the applicable energy performance metric 
for refrigeration systems.
---------------------------------------------------------------------------

    \26\ Available at www.ahrinet.org.
---------------------------------------------------------------------------

    The DOE test procedure for walk-in refrigeration systems 
incorporates by reference the test procedure in AHRI 1250-2009 
(excluding Tables 15 and 16), with certain enumerated modifications. 
See appendix C to subpart R of part 431.
    In April 2020, AHRI published AHRI 1250-2020, which incorporates 
many of the modifications and additions to AHRI 1250-2009 that DOE 
currently prescribes in its test procedure at appendix C. It also 
includes test methods for unit coolers and dedicated condensing units 
tested alone, rather than incorporating by reference updated versions 
of AHRI 420-2008 and/or ASHRAE 23.1-2010. AHRI 1250-2020 also includes 
test methods for single-packaged dedicated systems.
    The following sections discuss the amendments being adopted in 
appendix

[[Page 28792]]

C and appendix C1 with respect to the aforementioned industry test 
methods.
a. Appendix C
    In the April 2022 NOPR, DOE proposed minor modifications to 
appendix C that improve test procedure accuracy and repeatability, 
while maintaining equivalent measurements of AWEF. 87 FR 23920, 23933. 
As discussed further in the section that follows, DOE also proposed to 
establish a new appendix C1 to subpart R that would incorporate 
substantive changes that would result in different measured values of 
efficiency, AWEF2, compared to appendix C. DOE proposed that the use of 
appendix C with the proposed amendments would be required 180 days 
after this test procedure final rule is published and would remain 
required for use until the compliance date of any future amended energy 
conservation standards based on appendix C1.
    Within appendix C, DOE proposed to maintain reference to AHRI 1250-
2009. DOE proposed to adopt certain instrument accuracy and test 
tolerances from AHRI 1250-2020 that would not change the measured AWEF 
value, as discussed further in section III.F.5 of this document.
    DOE received no comments on its proposal to maintain appendix C, 
with modification, until the compliance date of any future amended 
energy conservation standards based on appendix C1.
    In this final rule, DOE maintains the required use of appendix C, 
as amended by this final rule, including the incorporation by reference 
of AHRI 1250-2009, until the compliance date of any future amended 
energy conservation standards based on appendix C1.
b. Appendix C1
    As discussed, in the April 2022 NOPR, DOE proposed to establish a 
new appendix C1 to subpart R that incorporates by reference AHRI 1250-
2020. 87 FR 23920, 23933. DOE tentatively determined that the changes 
proposed in appendix C1 through the incorporation of AHRI 1250-2020 
would increase the representativeness of the DOE test procedure for 
walk-ins. DOE also tentatively determined that several of the changes 
in AHRI 1250-2020 would change the measured AWEF value. These changes 
can be grouped into five categories: off-cycle tests, single-packaged 
dedicated systems, defrost calculations, variable capacity, and default 
unit cooler parameters. These changes and the comments received on 
these proposed changes are discussed in detail in section III.G. Since 
these changes would result in a change to measured AWEF, DOE proposed 
to establish a new metric called ``AWEF2.''
    In the April 2022 NOPR, DOE proposed to incorporate AHRI 1250-2020 
for use in appendix C1, with the following exclusions:

 Section 1 Purpose
 Section 2 Scope
 Section 9 Minimum Data Requirements for Published Ratings
 Section 10 Marking and Nameplate Data
 Section 11 Conformance Conditions
 Section C10.2.1.1 Test Room Conditioning Equipment under 
section C10--Defrost Calculation and Test Methods

87 FR 23920, 23933.
    DOE proposed to exclude these sections of AHRI 1250-2020 because 
they either do not apply or conflict with other test procedure 
provisions included in appendix C1.
    Further, DOE proposed to reference ASHRAE 16-2016 in appendix C1, 
as it is referenced in AHRI 1250-2020, with the following exclusions:

 Section 1 Purpose
 Section 2 Scope
 Section 4 Classifications
 Normative Appendices E-M
 Informative Appendices N-R

87 FR 23920, 23934.
    DOE did not propose to reference these sections of ASHRAE 16-2016, 
as either they do not apply or they conflict with other test procedure 
provisions that are included as part of appendix C1.
    Similarly, DOE proposed to reference ASHRAE 37-2009 in appendix C1, 
as it is referenced in AHRI 1250-2020, with the following exclusions:

 Section 1 Purpose
 Section 2 Scope
 Section 4 Classifications
 Informative Appendix A Classifications of Unitary Air-
conditioners and Heat Pumps

Id.
    DOE did not propose to reference these sections of ASHRAE 37-2009, 
as either they do not apply, or they conflict with other test procedure 
provisions that are included as part of appendix C1.
    As discussed in the April 2022 NOPR, AHRI 1250-2020 incorporates 
many of the modifications and additions to AHRI 1250-2009 that DOE 
currently prescribes in its appendix C test procedure. Id. Since DOE 
proposed to adopt AHRI 1250-2020, DOE did not propose to carry over the 
sections listed in Table III.1 from appendix C to appendix C1.

 Table III.1--List of Sections in Appendix C Not Proposed To Be Included
                             in Appendix C1
------------------------------------------------------------------------
            Appendix C                             Summary
------------------------------------------------------------------------
Section 3.1.1.....................  Modifies Table 1 (Instrumentation
                                     Accuracy) in AHRI 1250-2009.
Section 3.1.2.....................  Provides guidance on electrical
                                     power frequency tolerances.
Section 3.1.3.....................  States that in Table 2 of AHRI 1250-
                                     2009, the test operating tolerances
                                     and test condition tolerances for
                                     air leaving temperatures shall be
                                     deleted.
Section 3.1.4.....................  States that in Tables 2 through 14
                                     in AHRI 1250-2009, the test
                                     condition outdoor wet-bulb
                                     temperature requirement and its
                                     associated tolerance apply only to
                                     units with evaporative cooling.
Section 3.1.5.....................  Provides tables to use in place of
                                     AHRI 1250-2009 Tables 15 and 16,
                                     which are excluded from the
                                     reference in 10 CFR 431.303.
Section 3.2.1.....................  Provides specific guidance on how to
                                     measure refrigerant temperature.
Section 3.2.2.....................  Removes the requirement to perform a
                                     refrigerant composition and oil
                                     concentration analysis.
Section 3.2.5.....................  Provides insulation and
                                     configuration requirements for
                                     liquid and suction lines used for
                                     testing.
Section 3.3.1.....................  Gives direction for how to test and
                                     rate unit coolers tested alone.
Section 3.3.2.....................  Clarifies that the 2008 version of
                                     AHRI Standard 420 should be used
                                     for unit coolers tested alone.
Section 3.3.3.....................  Modifies the allowable reduction in
                                     fan speed for off-cycle evaporator
                                     testing.
Section 3.4.1.....................  Specifies that the 2010 version of
                                     ASHRAE 23.1 should be used and that
                                     ``suction A'' condition test points
                                     should be used when testing
                                     dedicated condensing units.
Section 3.4.2.....................  Provides instruction on how to
                                     calculate AWEF and net capacity for
                                     dedicated condensing units.
Section 3.5.......................  Provides guidance on how to rate
                                     refrigeration systems with hot gas
                                     defrost.
------------------------------------------------------------------------


[[Page 28793]]

    AHRI 1250-2020 does not incorporate all the modifications and 
additions to AHRI 1250-2009 that DOE currently prescribes in its test 
procedure. Therefore, DOE proposed that the modifications in sections 
3.2.3, 3.3.4, 3.3.5, and 3.3.7 of appendix C be incorporated into 
appendix C1.
    In response to the April 2022 NOPR, DOE received several general 
comments about the incorporation of AHRI 1250-2020 for use in appendix 
C1. AHRI and National Refrigeration commented that they disagreed with 
DOE aligning appendix C1 with AHRI 1250-2020 and requested further 
clarification on the proposal. (AHRI, No. 30 at p. 7; National 
Refrigeration, No. 39 at p. 2) Neither AHRI nor National Refrigeration 
provided detail about what specifically they disagreed with, or which 
aspects of DOE's proposal required further clarification.
    In response to the April 2022 NOPR, HTPG requested details on the 
changes in the new appendix C1 that may impact the determination of 
AWEF for unit coolers and variable-capacity systems. (HTPG, No. 32 at 
p. 2) These topics are discussed in detail in sections III.G.7 and 
III.G.11 of this document, respectively.
    As discussed in this section and in more detail in section III.G, 
DOE has concluded that the changes in AHRI 1250-2020 improve the 
representativeness of the walk-in refrigeration systems test procedure. 
Therefore, DOE is incorporating AHRI 1250-2020, ASHRAE 37-2009, ASHRAE 
16-2016 for use in appendix C1 as proposed in the April 2022 NOPR.
c. Additional Amendments
    AHRI 1250-2020 includes additional amendments that are inconsistent 
with AHRI 1250-2009 but are either not referenced in the DOE test 
procedure or serve to make aspects of the test procedure more explicit 
or clear. None of these changes impact measured AWEF. These additional 
amendments are discussed in the paragraphs below.
    AHRI 1250-2020 added exclusions for liquid-cooled condensing 
systems in section 2.2.4 and excludes systems that use carbon dioxide, 
glycol, or ammonia as refrigerants in section 2.2.5. As mentioned 
previously, DOE is not incorporating section 2 of AHRI 1250-2020 into 
appendix C1.
    AHRI 1250-2020 includes an updated list of references and the 
applicable versions of certain test standards in appendix A, 
``References--Normative.'' DOE does not expect these changes to impact 
measured AWEF apart from ways discussed in section III.G. AHRI 1250-
2020 added specifications for refrigerant temperature measurement 
locations for unit coolers tested alone, matched pairs, and dedicated 
condensing systems tested alone in sections C3.1.3.1, C3.1.3.2, and 
C3.1.3.3. DOE has determined that these specifications will not affect 
measured AWEF.
    AHRI 1250-2020 revised section C7.5.1 to provide more detailed 
instructions for calculating system capacity beginning with measured 
temperatures and pressures instead of calculated enthalpies, which is 
what was done in AHRI 1250-2009. Section C7.5.1 also includes the 
determination of capacity from enthalpy calculation results. The 
addition of these sections provides clarity and further instruction but 
does not affect measured AWEF.
    AHRI 1250-2009 included section C12, ``Method of Testing Condensing 
Units for Walk-in Cooler and Freezer Systems for Use in Mix-Match 
System Ratings,'' which referenced ASHRAE 23.1-2010. AHRI 1250-2020 now 
provides specific methods for testing dedicated condensing units tested 
alone. DOE has determined that the test procedure incorporated into 
AHRI 1250-2020 is the same as that in ASHRAE 23.1-2010 and therefore 
does not impact measured AWEF.
    Section C13 of AHRI 1250-2009, ``Method of Testing Unit Coolers for 
Walk-in Cooler and Freezer Systems for Use in Mix-Match System 
Ratings,'' referenced AHRI 420-2008. AHRI 1250-2020 no longer 
references AHRI 420-2008 and instead outlines a method for unit coolers 
tested alone. DOE has determined that the test procedure incorporated 
into AHRI 1250-2020 is the same as that in ASHRAE AHRI 420-2008 and 
therefore does not impact measured AWEF. As a result, DOE is not 
incorporating by reference AHRI 420-2008 in new appendix C1.

C. Amendments to Appendix A for Doors

    Appendix A provides test procedures for measuring walk-in envelope 
component energy consumption. Specifically, appendix A provides the 
test procedures to determine the U-factor, conduction load, and energy 
use of walk-in display panels and to determine the energy use of walk-
in display doors and non-display doors (see section III.D for 
discussion of display panels).
    In the April 2022 NOPR, DOE proposed several changes to appendix A 
specific to display doors and non-display doors. 87 FR 23920, 23936-
23943. DOE determined that these changes would improve test 
representativeness and repeatability. DOE stated in the April 2022 NOPR 
that it did not expect the changes it proposed to have a substantive 
impact on measured energy consumption calculations for display doors or 
non-display doors, except in the case of testing doors with motors.
    The following sections describe the modifications that DOE proposed 
to appendix A with respect to walk-in display and non-display doors.
1. Reference to NFRC 102-2020 in Place of NFRC 100-2010 and Alternative 
Efficiency Determination Methods for Doors
a. NFRC 102-2020 in Place of NFRC 100-2010
    Appendix A references NFRC 100-2010 as the method for determining 
the U-factor of doors and display panels. NFRC 100-2010 allows for 
computational determination of U-factor by simulating U-factor using 
Lawrence Berkeley National Lab's (LBNL) WINDOW and THERM software, 
provided that the simulated value for the baseline product in a product 
line is validated with a physical test of that baseline product and the 
simulated value is within the accepted agreement with the physical test 
value as specified in section 4.7.1 of NFRC 100-2010.\27\
---------------------------------------------------------------------------

    \27\ Section 4.7.1 of NFRC 100-2010 requires that the accepted 
difference between the tested U-factor and the simulated U-factor be 
(a) 0.03 Btu/(h-ft\2\-[deg]F) for simulated U-factors that are 0.3 
Btu/(h-ft\2\-[deg]F) or less, or (b) 10 percent of the simulated U-
factor for simulated U-factors greater than 0.3 Btu/(h-ft\2\-
[deg]F). This agreement must match for the baseline product in a 
product line. Per NFRC 100, the baseline product is the individual 
product selected for validation; it is not synonymous with ``basic 
model'' as defined in 10 CFR 431.302.
---------------------------------------------------------------------------

    As discussed in the April 2022 NOPR, DOE is aware there has been 
limited success using the computational method in NFRC 100-2010 to 
simulate U-factors of non-display doors. 87 FR 23920, 23936-23937. 
Thus, DOE proposed to remove reference to NFRC 100-2010 (i.e., the 
computational method) and instead reference NFRC 102-2020 (i.e., the 
physical test method) for determining U-factor. Id. Consistent with 
that proposal, and with stakeholder concerns regarding test burden 
given the highly customizable nature of the walk-in door market, DOE 
also proposed to allow use of alternative efficiency determination 
methods (AEDMs) to determine the represented value of energy 
consumption of walk-in doors at 10 CFR 429.53(a)(3). 87 FR 23920, 
23972.
    In response, Bally stated that it looks forward to using AEDMs to 
rate its walk-in doors. (Bally, No. 40 at p. 5) RSG also agreed with 
the proposal to allow for AEDMs. (RSG, No. 41 at p. 2)

[[Page 28794]]

    Hussmann noted that, although it is ``not pleased'' with the 
current NFRC 100-2010 test method, it does not support use of an AEDM 
because it believes rating with an AEDM creates an opportunity for 
``approved non-compliance.'' (Hussmann, No. 34 at pp. 3-4)
    DOE acknowledges Hussmann's concern but notes that rating a basic 
model with an AEDM does not excuse a manufacturer from complying with 
the relevant energy conservation standards. DOE has several 
requirements pertaining to AEDM records retention; the ability to 
provide analyses, conduct simulations, or conduct certification testing 
of basic models rated with the AEDM at DOE's request; and verification 
testing of an AEDM by DOE. These requirements can be found in 10 CFR 
429.70(f)(3) through (5). DOE enforces all these requirements.
    DOE notes that despite the limited success historically with using 
the computational method in NFRC 100-2010, to the extent that 
manufacturers have successfully used the simulation method in NFRC 100-
2010 to produce accurate results, such results would be acceptable as 
an AEDM. AEDMs and the specific provisions DOE is adopting pertaining 
to AEDMs for doors are explained and discussed in the following 
section.
b. Alternative Efficiency Determination Methods for Doors
    Pursuant to the requirements of 10 CFR 429.70, DOE may permit use 
of an AEDM in lieu of testing equipment for which testing burden may be 
considerable and for which that equipment's energy efficiency 
performance may be well predicted by such alternative methods. Although 
specific requirements vary by product or equipment, use of an AEDM 
entails development of a mathematical model that estimates energy 
efficiency or energy consumption characteristics of the basic model, as 
would be measured by the applicable DOE test procedure. The AEDM must 
be based on engineering or statistical analysis, computer simulation or 
modeling, or other analytic evaluation of performance data. A 
manufacturer must perform validation of an AEDM by demonstrating that 
the performance, as predicted by the AEDM, agrees with the performance 
as measured by actual testing in accordance with the applicable DOE 
test procedure. The validation procedure and requirements, including 
the statistical tolerance, number of basic models, and number of units 
tested vary by product or equipment.
    Once developed and validated, an AEDM may be used to rate and 
certify the performance of untested basic models in lieu of physical 
testing. Use of an AEDM for any basic model is always at the option of 
the manufacturer. One potential advantage of AEDM use is that it may 
free a manufacturer from the burden of physical testing. One potential 
risk is that the AEDM may not perfectly predict performance, and the 
manufacturer could be found responsible for having an invalid rating 
for the equipment in question or for having distributed a noncompliant 
basic model. The manufacturer, by using an AEDM, bears the 
responsibility and risk of the validity of the ratings.
    For walk-ins, DOE currently permits the use of AEDMs for 
refrigeration systems only. 10 CFR 429.70(f). As discussed previously, 
DOE proposed to allow the use of AEDMs for rating walk-in doors in the 
April 2022 NOPR. 87 FR 23920, 23972. Concurrent with this proposal, DOE 
proposed a number of provisions specific to the validation and use of 
an AEDM. First, DOE proposed to include walk-in door validation classes 
at 10 CFR 429.70(f)(2)(iv) and to require that two basic models per 
validation class be tested using the proposed test procedure in 
appendix A, which is consistent with the number of basic models 
required to be tested per validation class for walk-in refrigeration 
systems. Id.
    Second, DOE proposed to include a 5 percent individual model 
tolerance, which aligns with the individual model tolerance applicable 
to walk-in refrigeration systems, to validate the measured energy 
consumption result of an AEDM with the appendix A test result at 10 CFR 
429.70(f)(2)(ii). Id. The individual model tolerance is used to 
validate the AEDM. This means that when validating the AEDM for use, 
the predicted daily energy consumption for each model calculated by 
applying the AEDM may not be more than 5 percent less than the daily 
energy consumption determined from the corresponding test of the model.
    DOE also proposed that an AEDM for doors can only simulate or model 
characteristics of the door that are required to be tested by the DOE 
test procedure--i.e., for the doors test procedure, the AEDM would be 
used to simulate or model the U-factor, which is the only part of the 
appendix A test procedure that is not a calculation. The AEDM cannot be 
used to simulate or model the energy consumption due to conduction 
thermal load, or the direct and indirect electrical energy consumption 
of electricity-consuming devices sited on the door--those must be 
calculated using the appendix A test procedure. However, when 
validating the AEDM, the comparison between a door that has been 
physically tested versus a door that has been modeled or simulated must 
be done using the complete metric (i.e., total daily energy 
consumption). In other words, the AEDM can only be used to determine 
the U-factor, but the total daily energy consumption using an AEDM must 
be carried out using the calculations in appendix A for the energy 
consumption due to conduction thermal load, and the direct and indirect 
electrical energy consumption. Then, the validation of an AEDM would 
compare the energy consumption calculated using a simulated U-factor 
with the energy consumption calculated using a tested U-factor.
    Lastly, DOE proposed to include a 5 percent tolerance applicable to 
the maximum daily energy consumption metric for AEDM verification 
testing conducted by DOE at 10 CFR 429.70(f)(5)(vi), which aligns with 
the tolerance applicable to AWEF of walk-in refrigeration systems. Id. 
DOE may randomly select and test a single unit of a basic model to 
assess whether a basic model is in compliance with the applicable 
energy conservation standards pursuant to 10 CFR 429.104, which extends 
to all DOE covered products and equipment, including those certified 
using an AEDM. As part of the AEDM requirements, DOE may use the test 
data from an assessment test for a given model to verify the certified 
rating determined by an AEDM. This is called verification testing. See 
10 CFR 429.70(f)(5). For doors using an energy consumption metric, the 
result from a DOE verification test must be less than or equal to the 
certified rating multiplied by (1 plus the applicable tolerance); i.e., 
the DOE verification test result must be less than or equal to 105 
percent of the certified rating.
    In the April 2022 NOPR, DOE requested comment on the specific 
proposals pertaining to the validation and use of AEDMs for doors. Id. 
RSG agreed with the proposals. (RSG, No. 41 at p. 2)
    Anthony disagreed with DOE removing the reference to NFRC 100-2010 
for NFRC 102-2020 and allowing AEDMs because it believes an AEDM would 
require more testing and result in an increased financial and physical 
burden on manufacturers without achieving an additional energy benefit. 
(Anthony, No. 31 at pp. 3, 8-9) Additionally, Anthony stated that if 
NFRC 100-2010 is able to be used as an AEDM, the application of the 5 
percent

[[Page 28795]]

tolerance on the energy consumption metric, Edd, would 
conflict with the NFRC 100-2010 standard without achieving an 
additional energy benefit. Id. AHRI commented that the AEDM strategy 
with respect to U-factor is unclear and requested clarification of what 
the proposed 5 percent model tolerance applies to. (AHRI, No. 30 at p. 
11)
    DOE is clarifying that to use an AEDM, the manufacturer must first 
validate the AEDM. To validate the AEDM, the manufacturer must select 
at least the minimum number of basic models for each validation class 
(specified in table 1 to 10 CFR 429.70(f)(2)(iv)(A)) and physically 
test a single unit of each basic model. Thus, for a single validation 
class, where DOE proposed two basic models be tested per validation 
class, only two physical tests would be required, although more testing 
may be conducted at the manufacturer's discretion. The manufacturer 
would be required to conduct the physical U-factor tests according to 
NFRC 102-2020 referenced by appendix A and carry out the energy 
consumption calculations as done in appendix A. For the AEDM, the 
manufacturer would model or simulate the U-factor using a method of 
their choice, and then carry out the energy consumption calculations as 
done for the physical test, only deviating by using the simulated U-
factor in the calculations. All other parts of the energy consumption 
calculations shall be done according to appendix A and may not be 
modeled. To validate the AEDM, the energy consumption output using the 
physical test must be compared with the energy consumption output using 
the AEDM for each basic model used for validation. If the output using 
the AEDM is lower than the physical test output by more than the 
individual model tolerance (i.e., 5 percent), then the AEDM is not 
valid. If the output using the AEDM is greater than or equal to 95 
percent of the output using physical testing and meets the standard for 
at least two basic models, then the AEDM has been validated for that 
validation class.
    To illustrate the minimum number of physical tests required, 
consider an example of a display door manufacturer that produces models 
in two validation classes: medium-temperature and low-temperature. This 
manufacturer would need to, at a minimum, physically test the U-factor 
and calculate the energy consumption of two basic models per validation 
class, thus requiring a total of four physical tests: two for the 
medium-temperature display door validation class and two for the low-
temperature display door validation class. The manufacturer would use 
the U-factor test results to calculate the total daily energy 
consumption each door. Then, the manufacturer would use their AEDM to 
model or simulate the U-factor of each door and calculate each door's 
total daily energy consumption. Each basic model's simulated and tested 
total daily energy consumption results would be compared using the 
tolerance of 5 percent in order to validate the AEDM. DOE stresses that 
this 5 percent tolerance used to validate the AEDM would only apply to 
the comparison of tested and simulated energy consumption for the 
minimum number of models physically tested for validation of the AEDM. 
If the AEDM is validated, the manufacturer could then use the AEDM to 
rate the remainder of the basic models it manufacturers in those 
validation classes. The 5 percent tolerance would not be used for any 
models simulated without a physical test because the AEDM was validated 
and thus no physical test would be further required.
    DOE emphasizes that allowing use of an AEDM would provide 
manufacturers with the flexibility to use an alternative method (i.e., 
besides NFRC 100-2010) that yields the best agreement with a physical 
test for their doors. Additionally, DOE notes that the change in test 
burden associated with the use of an AEDM is dependent on a 
manufacturer's product offerings. If a manufacturer does not have 
success with NFRC 100-2010 and is currently required to physically test 
all basic models, the AEDM option may reduce the test burden by 
requiring only two basic models per validation class to be tested. DOE 
is aware there has been limited success using the computational method 
in NFRC 100-2010 to simulate U-factors of non-display doors. Therefore, 
DOE expects a reduction of test burden across the industry since 
allowing AEDMs generally provides manufacturers, particularly those 
that manufacture non-display doors, the flexibility to use an alternate 
method that works best for them and meets the AEDM criteria established 
by DOE. However, if a manufacturer currently has success using NFRC 
100-2010, there could be an increase in test burden, but only if the 
manufacturer currently validates the use of the simulation method with 
less than two basic models per validation class. Test burden and costs 
are discussed further in section III.K.1 of this document. The 
inclusion of AEDM provisions would enable manufacturers to continue 
using NFRC 100-2010, provided that manufacturers meet the AEDM 
requirements in 10 CFR 429.53 and 429.70(f). Therefore, DOE is removing 
reference to NFRC 100-2010 from its test procedure and is instead 
referencing NFRC 102-2020 and adopting provisions that allow 
manufacturers to use an AEDM, as proposed in the April 2022 NOPR.
c. Exceptions to the Industry Test Method for Determining U-Factor
    Section 5.3 of appendix A references NFRC 100-2010 for determining 
U-factor, and section 5.3(a) of appendix A specifies four exceptions to 
that industry standard. The first exception implements a tolerance on 
the surface heat transfer coefficients (no such tolerance is specified 
in NFRC 100-2010); specifically, that the average surface heat transfer 
coefficients during a test must be within  5 percent of the 
values specified through NFRC 100-2010 in ASTM C1199. The second and 
third exceptions modify the cold and warm-side conditions from the 
standard conditions prescribed in NFRC 100-2010. The fourth exception 
specifies the direct solar irradiance be 0 Btu/(h-ft\2\).
    Sections 6.2.3 and 6.2.4 of ASTM C1199 specify the standardized 
heat transfer coefficients and their tolerances as part of the 
procedure to set the surface heat transfer conditions of the test 
facility using the Calibration Transfer Standard (``CTS'') test. The 
warm-side surface heat transfer coefficient must be within  
5 percent of the standardized warm-side value of 1.36 Btu/(h-ft\2\-
[deg]F), and the cold-side surface heat transfer coefficient must be 
within  10 percent of the standardized cold-side value of 
5.3 Btu/(h-ft\2\-[deg]F) during the CTS test (ASTM C1199, sections 
6.2.3 and 6.2.4). ASTM C1199 does not require that the measured surface 
heat transfer coefficients match or be within a certain tolerance of 
standardized values during the official sample test--although test 
facility operational (e.g., cold-side fan settings) conditions would 
remain identical to those set during the CTS test. ASTM C1199 also does 
not require measurement of the warm-side surface temperature of the 
door. Rather, this value is calculated based on the radiative and 
convective heat flows from the test specimen's surface to the 
surroundings, which are driven by values determined from the 
calibration of the hot box using the CTS test (e.g., the convection 
coefficient). See ASTM C1199, section 9.2.1.
    As discussed in the April 2022 NOPR, DOE has found that obtaining 
the standardized heat transfer values within the  5 percent 
tolerance specified in section 5.3(a)(1) of appendix A on the

[[Page 28796]]

warm side and cold side may not be achievable depending on the thermal 
transmittance through the door. 87 FR 23920, 23937. In the April 2022 
NOPR, DOE proposed to remove the exceptions specified in section 
5.3(a)(1) of appendix A regarding the surface heat transfer 
coefficients and the tolerances on them during testing.
    DOE did not receive any comments on its proposal to remove the 
exceptions specified in section 5.3(a)(1) of appendix A.
    For the reasons discussed in the preceding paragraphs and the April 
2022 NOPR, DOE is removing the exceptions listed in section 5.3(a)(1) 
of appendix A regarding the surface heat transfer coefficients and the 
tolerances on them during testing. 87 FR 23920, 23937-23938. By 
removing these exceptions, the requirements pertaining to the surface 
heat transfer coefficients would apply as they are specified in the 
referenced industry standards.
    Relatedly, Anthony commented on the specific values used to define 
the surface heat transfer coefficients. Specifically, Anthony commented 
that it disagrees with the current surface heat transfer coefficient 
applied to the cold side during testing and simulation of U-factors for 
display doors. (Anthony, No. 31 at pp. 4-5) Anthony presented data from 
field testing at several different public locations showing that the 
actual measured wind speed is on average 84 percent less than specified 
in NFRC 102-2020 and NFRC 100-2010, as well as a measured wind speed 
from their test cell showing an average of 1.1 miles per hour 
(``mph''). Anthony recommended that DOE adopt a cold-side heat transfer 
coefficient corresponding to a conservative wind speed value of 5 mph. 
Id.
    DOE notes that deviating from the existing surface heat transfer 
coefficients would require test labs to change their test chamber 
calibration procedures and would require manufacturers to retest and 
rerate all envelope components subject to the energy consumption test 
procedure in appendix A. DOE has evaluated the data and information 
provided by Anthony but is unable to establish at this time whether 
such changes to the heat transfer coefficient would be nationally 
representative, nor the extent to which any such improvement in 
representativeness of the test result would outweigh the test burden 
associated with changing the heat transfer coefficient value. DOE has 
therefore determined it is not appropriate to amend the heat transfer 
coefficients in this final rule.
    Additionally, section 5.3(a)(1) of appendix A currently specifies a 
direct solar irradiance \28\ of 0 Btu/h-ft\2\. Consistent with DOE's 
removal of its reference to NFRC 100-2010, DOE is removing the 
requirement of direct solar irradiance of 0 Btu/h-ft\2\ in section 
5.3(a)(4) of appendix A. DOE received no comment on solar irradiance in 
response to the April 2022 NOPR and notes that the removal of this 
requirement would not affect measured values. 87 FR 23920, 23938.
---------------------------------------------------------------------------

    \28\ Solar irradiance is the power per unit area received from 
the sun in the form of electromagnetic radiation.
---------------------------------------------------------------------------

2. Additional Definitions
a. Surface Area for Determining Compliance With Standards
    Surface area of a door is used in two ways in the regulations at 
subpart R of 10 CFR431: (1) to convert the tested U-factor of the door 
into a conduction load as part of the energy consumption test 
procedure, and (2) to determine compliance with the maximum energy 
consumption standards. As currently defined in section 3.4 of appendix 
A, surface area means the area of the surface of the walk-in component 
that would be external to the walk-in cooler or walk-in freezer as 
appropriate. The definition does not provide detail on how to determine 
the boundaries of the walk-in door from which height and width are 
determined to calculate surface area. Additionally, the definition does 
not specify if these measurements are to be strictly in-plane with the 
surface of the wall or panel that the walk-in door would be affixed to, 
or if troughs and other design features on the exterior surface of the 
walk-in door should be included in the measured surface area.
    In the April 2022 NOPR, DOE proposed that the surface area bounds 
of both display doors and non-display doors be the outer edge of the 
frame. 87 FR 23920, 23939. DOE proposed to change the term from 
``surface area'' to ``door surface area,'' and to define the term as 
meaning the product of the height and width of a walk-in door measured 
external to the walk-in. Id. Under this definition, the height and 
width dimensions would be perpendicular to each other and parallel to 
the wall or panel of the walk-in to which the door is affixed, the 
height and width measurements would extend to the edge of the frame and 
frame flange (as applicable) to which the door leaf is affixed, and the 
surface area of a display door and non-display door would be 
represented as Add and And, respectively.
    In addition, DOE proposed to move the defined term from the test 
procedure in appendix A to the definition section in 10 CFR 431.302 
with the other definitions that are broadly applicable to subpart R. 
Id. DOE proposed this move because, as revised and in light of the 
following section III.C.2.b of this document, this term would no longer 
be used to convert the tested U-factor of the door into a conduction 
load as part of the energy consumption test procedure and is only 
relevant for determining compliance with the energy conservation 
standards. Id.
    Anthony agreed with the proposed revision of using the external 
frame dimensions, which includes the flange, for determining 
Add and for determining the maximum energy consumption 
standard. (Anthony, No. 31 at p. 5)
    Bally suggested that the surface area definition should include 
electrical conduit and pressure relief vents, not pieces of the door 
with low conductivity. (Bally, No. 40 at pp. 1-2) Bally also commented 
that it disagrees with DOE's discussion in the April 2022 NOPR that if 
the surface area of a door is measured without the frame, then it 
should be considered a panel. (Id.) Senneca stated that the outside 
dimensions of the frame should not be included in the surface area 
measurement because the frame mounts directly to the insulated panel 
and, therefore, the backside of the frame is not exposed directly to 
the cold-side temperature. (Senneca, No. 26 at p. 2) Additionally, 
Senneca described that a door with a longer track would require a 
longer frame and therefore would have a larger surface area; however, 
it stated that the larger frame would have no bearing on the energy 
consumption because, as mentioned, the backside of the frame is not 
exposed directly to the cold-side temperature. (Id.)
    Senneca also stated that with the proposal for the door frame to be 
included in the surface area, it believes there is ambiguity in 
measuring sliding doors that have a track extending past the door 
frame. (Id.) DOE has considered Senneca's comment specific to sliding 
doors and acknowledges that the track of a horizontal sliding door may 
extend significantly beyond the width of the door leaf and door frame 
or casings and attach to the panels adjacent to the door, which would 
result in a significant increase in ``door surface area'' if the track 
width were to be included in the area measurement. Therefore, DOE has 
concluded that the portion of the track that extends beyond the 
external width (for a horizontal sliding door) or external height (for 
a vertical sliding door) of the door leaf or

[[Page 28797]]

leaves and its frame or casings should be excluded from the surface 
area measurement used to determine compliance with the standards. DOE 
notes that given the equipment it is aware of on the market, this 
additional instruction will likely only impact the bounds of sliding 
non-display doors. DOE notes that sliding display doors typically have 
tracks that are integrated completely into the frame of the entire door 
system, thus the entire track is expected to be included in the 
determination of surface area.
    DOE has considered stakeholder opposition to including the frame in 
the door surface area measurement but has determined that the 
definition of ``door'' includes the frame for consistent comparison 
across door products offered. DOE recognizes that non-display doors may 
have variations in the frames used, where some look similar to panels 
but tend to have electrical components wired through them, while others 
look more like casings used in replacement installations. DOE also 
recognizes that non-display doors may have variations in the 
installation of doors, where parts of the door frame may or may not be 
in direct contact with the cold side of the walk-in. However, DOE 
intends to consistently evaluate different products and sees a need to 
have consistent instructions on determining the bounds of surface area 
for all walk-in doors. DOE has determined that all parts of the door 
that impact the operation of the door shall be included in the 
determination of the surface area, with the exception of extended track 
area for sliding doors as discussed previously. Therefore, the bounds 
of the ``door surface area'' dimensions also include the frame.
    As proposed in the April 2022 NOPR, in this final rule, DOE is 
defining ``door surface area'' as the product of the height and width 
of a walk-in door measured external to the walk-in. The height and 
width dimensions shall be perpendicular to each other and parallel to 
the wall or panel of the walk-in to which the door is affixed. The 
height and width measurements shall extend to the edge of the frame and 
frame flange (as applicable) to which the door is affixed. For sliding 
doors, the height and width measurements shall include the track; 
however, the width (for horizontal sliding doors) or the height (for 
vertical sliding doors) shall be truncated to the external width or 
height of the door leaf or leaves and its frame or casings. The surface 
area of a display door is represented as Add, and the 
surface area of a non-display door is represented as And.
b. Surface Area for Determining U-Factor
    As stated previously, appendix A currently references NFRC 100-
2010, which in turn references NFRC 102 for the determination of U-
factor through a physical test. When conducting physical testing, the 
U-factor (Us) is calculated using projected surface area 
(As) and then converted to the final standardized U-factor 
(UST). See ASTM C1199, sections 8.1.3 and 9.2.7, as 
referenced through NFRC 102. Projected surface area (As) is 
defined as ``the projected area of test specimen (same as test specimen 
aperture in surround panel).'' See ASTM C1199, section 3.3, as 
referenced through NFRC 102.
    Currently, equations 4-19 and 4-28 of appendix A specify that 
surface area of display doors (Add) and non-display doors 
(And), respectively, are used to convert a door's U-factor 
into a conduction load. This conduction load represents the amount of 
heat that is transferred from the exterior to the interior of the walk-
in.
    As discussed in section III.C.2.a, DOE is amending the definitions 
of And and Add to be specific to the exterior 
dimensions of the door, including the frame and frame flange as 
appropriate. Defining the bounds of the door through this definition is 
inconsistent with the defined area (As) used to calculate U-
factor in NFRC 102-2020.
    In the April 2022 NOPR, DOE proposed to specify that the projected 
area of the test specimen, As, as defined in ASTM C1199, or 
the area used to determine U-factor is the area used for converting the 
standardized tested U-factor, UST, into a conduction load in 
appendix A. 87 FR 23920, 23940. DOE recognizes that this may not change 
ratings for some doors, where As is equivalent to 
And or Add, but it may result in slightly lower 
ratings of energy consumption for other doors, where As is 
less than And or Add. DOE expects that since this 
proposed detail would either result in a reduced measured energy 
consumption or have no impact, there will likely be no need for 
manufacturers to retest or rerate. Additional details on how this 
detail impacts retesting and rerating are further discussed in section 
III.K.1 of this document.
    Anthony commented that it agrees with the proposed revision to use 
the area of the test specimen, As, to calculate the 
conduction load. (Anthony, No. 31 at p. 6) Bally reiterated comments 
from AHRI, Hussmann, and Imperial Brown in response to the June 2021 
RFI which suggested they did not see a distinction that warranted 
changing the definition. (Bally, No. 40 at p. 1) See summary of these 
comments at 87 FR 23920, 23939.
    DOE reiterates that the door surface area defined in section 
III.C.2.a differs from the surface area used to calculate U-factor in 
NFRC 102-2020. Thus, despite stakeholder comments, DOE sees a need to 
resolve this discrepancy. Otherwise, the conduction load determined 
from the physical U-factor test may inflate the actual conduction load.
    In the April 2022 NOPR, DOE also proposed to specify in appendix A 
that the physical U-factor test should include all components of the 
door that aid in the operation of the door, including the frame, rather 
than just the door leaf, to improve consistency in application of the 
test procedure across all walk-in doors. 87 FR 23920, 23940. Bally 
commented that it does not believe the frame of the door should be 
included in the U-factor test and suggested that including the frame in 
the U-factor test was minimal in comparison to the electrical 
components. (Bally, No. 40 at pp. 2-3) As stated in the April 2022 
NOPR, DOE's testing of non-display doors has demonstrated that 
including the frame in the U-factor test has a measurable impact on the 
thermal performance of the door assembly relative to the increase in 
the total area, and so DOE is adopting the specification that the 
physical U-factor test should include the door frame.
3. Electrical Door Components
    Sections 4.4.2 and 4.5.2 of appendix A currently include provisions 
for calculating the direct energy consumption of electrical components 
of display doors and non-display doors, respectively. Electrical 
components associated with doors could include, for example, heater 
wire (for anti-sweat or anti-freeze applications), lights (including 
display door lighting systems), control system units, or sensors. For 
each electricity consuming component, the calculation of energy 
consumption is based on the component's ``rated power'' rather than a 
measurement of its power draw. Section 3.5 of appendix A defines 
``rated power'' as the electricity consuming device's power as 
specified (1) on the device's nameplate or (2) on the device's product 
data sheet if the device does not have a nameplate or such nameplate 
does not list the device's power.
    As discussed in the April 2022 NOPR, DOE has observed issues that 
make calculating a door's total energy consumption a challenge. 87 FR 
23920, 23940. These issues include using a

[[Page 28798]]

single nameplate for all door electrical components rather than 
individual nameplates for all electricity-consuming devices, 
specification of voltage and amperage rather than wattage on the 
nameplate, and no specification of whether the nameplate represents the 
maximum or steady-state operating conditions. DOE is aware that 
measuring direct power consumption of each electrical component could 
alleviate some of these issues. In response to the April 2022 NOPR, the 
Efficiency Advocates stated that they support an option for direct 
measurement of door component electrical power in the test procedure 
(Efficiency Advocates, No. 37 at p. 4). DOE acknowledges the comment 
but has concluded that additional investigation is needed to develop a 
test procedure for such measurements. Therefore, DOE is not adopting 
provisions requiring measurement of power consumption of each 
electrical door component in appendix A.
    Furthermore, DOE has observed that some manufacturers may be 
certifying door motor power as the output power rating of the motor, 
rather than the input power of the motor. Thus, DOE proposed in the 
April 2022 NOPR to specify in appendix A that the rated power of each 
electrical component, Prated,u,t, would be the rated input 
power of each component because the input power represents power 
consumption. The Efficiency Advocates also supported the clarification 
that the certified door motor power should be the input power. Id.
    Additionally, DOE has observed through testing that the measured 
power of some walk-in door electrical components exceeds either the 
certified or nameplate power values of these electrical components. In 
the April 2022 NOPR, DOE proposed that for the purposes of enforcement 
testing, in 10 CFR 429.134(q), DOE may validate the certified or 
nameplate power values of an electrical component by measuring the 
power when the device is energized using a power supply that provides 
power within the allowable voltage range listed on the nameplate. If 
the measured input power is more than 10 percent higher than the power 
listed on the nameplate or the rated input power in a manufacturer's 
certification, then the measured input power would be used in the 
energy consumption calculation. For electrical components with 
controls, the maximum input wattage observed while energizing the 
device and activating the control would be considered the measured 
input power. Anthony agreed with the proposal to use nameplate values 
for determining energy consumption unless physical testing results in a 
power value that exceeds what is depicted on the nameplate. (Anthony, 
No. 31 at p. 6) Bally stated that adjusting nameplate values based on 
measurement results requires door manufacturers to be responsible for 
the quality assurance of their vendors. (Bally, No. 40 at p. 3) In 
response, DOE notes that the door manufacturer is ultimately 
responsible for certifying that the walk-in door, when outfitted with 
all necessary components, meets the applicable DOE energy conservation 
standards.
    Given DOE's observations during testing, DOE sees a need to provide 
a way to calculate energy consumption using a measured value of 
electrical component power. DOE recognizes that there may be minor 
variations in measured power as compared to the rated power and has 
determined that a tolerance of 10 percent accounts for such variation. 
DOE is adopting this provision at 10 CFR 429.134(q)(4) only for the 
purposes of enforcement testing to aid the Department in determining 
non-compliance with energy conservation standards.
4. Percent Time Off Values
    The current test procedure assigns percent time off (``PTO'') 
values to various walk-in door components to reflect the hours in a day 
that an electricity-consuming device operates at its full rated or 
certified power. PTO values are not incorporated in the rated or 
certified power of an electricity-consuming device. Table III.2 lists 
the PTO values in the current DOE test procedure for walk-in door 
components.

      Table III.2--Assigned PTO Values for Walk-In Door Components
------------------------------------------------------------------------
                                                           Percent time
                     Component type                       Off (PTO)  (%)
------------------------------------------------------------------------
Lights without timers, control system, or other demand-               25
 based control..........................................
Lights with timers, control system, or other demand-                  50
 based control..........................................
Anti-sweat heaters without timers, control system, or                  0
 other demand-based control.............................
Anti-sweat heaters on walk-in cooler doors with timers,               75
 control system, or other demand-based control..........
Anti-sweat heaters on walk-in freezer doors with timers,              50
 control system, or other demand-based control..........
All other electricity-consuming devices without timers,                0
 control system, or other auto-shut-off system..........
All other electricity-consuming devices for which it can              25
 be demonstrated that the device is controlled by a
 preinstalled timer, control system, or auto-shut-off
 system.................................................
------------------------------------------------------------------------

    As mentioned in the April 2022 NOPR, DOE has granted waivers to 
several door manufacturers with motorized door openers, allowing the 
use of a different PTO for motors.\29\ 87 FR 23920, 23941. DOE proposed 
a single PTO for use with door motors to create consistency in the test 
procedure among doors with motors. 87 FR 23920, 23941-23942. DOE 
calculated an average PTO value based on the information in the waivers 
to determine a single representative PTO value. Considering the waivers 
and its calculations, DOE proposed to adopt a door motor PTO value of 
97 percent for all walk-in doors with motors. Id. Senneca and the 
Efficiency Advocates agreed with the proposed PTO. (Senneca, No. 26 at 
p. 2; Efficiency Advocates, No. 37 at p. 2) Bally suggested that the 
power consumption of the motor be completely removed from the energy 
consumption calculation, but ultimately supported the proposed PTO 
value. (Bally, No. 40 at p. 3) DOE has determined that motor power 
consumption contributes to direct and total energy consumption of the 
door and aids in the operation of the door. Therefore, the motor power 
should be included in the determination of energy consumption. 
Additionally, pursuant to its waiver regulations, as soon as 
practicable after the granting of any waiver, DOE will publish in the 
Federal Register a notice of proposed rulemaking to amend its 
regulations to eliminate any need for the continuation of such waiver. 
10 CFR 431.401(l). For the reasons stated above, DOE is adopting the 
PTO value of 97 percent

[[Page 28799]]

for door motors in appendix A. DOE notes that the adoption of this PTO 
value would not require retesting or recertification because calculated 
daily energy consumption will be equal to or lower than currently 
certified values. New testing would only be required if the 
manufacturer wishes to make claims using the new, more efficient 
rating.
---------------------------------------------------------------------------

    \29\ See HH Technologies, 83 FR 53457; Jamison Door Company, 83 
FR 53460; Senneca Holdings, 86 FR 75; Hercules, 86 FR 17801.
---------------------------------------------------------------------------

5. Energy Efficiency Ratio Values
    As discussed in the April 2022 NOPR, the energy efficiency ratio 
(``EER'') values used in appendix A differ from the EER values in 
appendix C. 87 FR 23920, 23942. The values in appendix A are used to 
calculate the daily energy consumption associated with heat loss 
through a walk-in door, and the values in appendix C correspond to 
adjusted dew point temperature when testing refrigeration systems of 
walk-in unit coolers alone. In the July 2021 RFI, DOE requested comment 
on the difference in EER values used in appendices A and C and based on 
stakeholder feedback, DOE concluded in the April 2022 NOPR that there 
is no advantage to harmonizing the two values. Id. As discussed in the 
April 2022 NOPR, an envelope component manufacturer cannot control what 
refrigeration equipment is installed and the EER values are intended to 
provide a nominal means of comparison rather than reflect an actual 
walk-in installation. Additionally, the difference between the EER 
values used in appendix A for doors and those used in appendix C for 
unit coolers is seven percent for coolers and five percent for 
freezers; however, changing the EER values would require manufacturers 
to retest and rerate energy consumption without necessarily providing a 
more representative test procedure. Id. Therefore, in the April 2022 
NOPR, DOE did not propose to harmonize the EER values between 
appendices A and C.
    In response to the April 2022 NOPR, Anthony suggested that DOE 
adopt the EER values specified in AHRI 1250 to align all components of 
a WICF and stated that the modification of EER values would not require 
additional testing, as these values are only used in the mathematical 
energy calculations. (Anthony, No. 31 at pp. 6-7) DOE notes that 
Anthony's suggested approach would require recalculation and 
recertification of every basic model and would do so without 
necessarily providing a more representative test procedure. As such, 
DOE has determined that changing the reference EER values in either 
appendix A or C would be unduly burdensome. Therefore, DOE is not 
harmonizing the EER values in appendices A and C.
6. Air Infiltration Reduction
    As discussed in the April 2022 NOPR, EPCA includes prescriptive 
requirements for doors used in walk-in applications intended to reduce 
air infiltration. 87 FR 23902, 23943. Specifically, walk-ins must have 
(A) automatic door closers that firmly close all walk-in doors that 
have been closed to within 1 inch of full closure (excluding doors 
wider than 3 feet 9 inches or taller than 7 feet), and (B) strip doors, 
spring-hinged doors, or other method of minimizing infiltration when 
doors are open. (42 U.S.C. 6313(f)(1)(A)-(B)) DOE previously proposed 
methods for determining the thermal energy leakage due to steady-state 
infiltration through the seals of a closed door and door opening 
infiltration. 75 FR 186, 196-197; 75 FR 55068, 55084-55085. DOE did not 
ultimately adopt these methods as part of the final test procedure 
because DOE concluded that steady state infiltration was primarily 
influenced by on-site assembly practices rather than the performance of 
individual components. 76 FR 21580, 21594-21595 (April 15, 2011). 
Similarly, DOE stated that, based on its experience with the door 
manufacturing industry, door opening infiltration is primarily reduced 
by incorporating a separate infiltration reduction device at the 
assembly stage of the complete walk-in. Id.
    In the April 2022 NOPR, DOE did not propose to include air 
infiltration in the test procedure. 87 FR 23920, 23943. However, the 
Efficiency Advocates encouraged DOE to incorporate a measurement of air 
infiltration for walk-in doors because it would improve the 
representativeness and encourage the development and deployment of 
technologies that can save energy. (Efficiency Advocates, No. 37 at p. 
4) DOE did not receive any data or recommendations for how to 
incorporate the measurement of air infiltration for walk-in doors into 
the test procedure in response to either the June 2021 RFI or the April 
2022 NOPR. DOE has concluded that additional investigation is needed to 
adopt a test procedure that considers air infiltration for walk-in 
doors and thus is not adopting provisions pertaining to air 
infiltration at this time. DOE intends to consider data on the 
magnitude of air infiltration for walk-ins as it becomes available for 
appropriate evaluation of the representativeness of including it in the 
test procedure for walk-in doors.
    As previously mentioned, EPCA requires air infiltration limiting 
devices on all doors. (42 U.S.C. 6313(f)(1)(A)-(B)) Even though air 
infiltration is not currently evaluated as part of the current test 
procedure and thus not part of the performance standard, all walk-in 
doors are subject to the prescriptive requirements in the energy 
conservation standard pertaining to air infiltration limiting devices. 
(10 CFR 431.306(a)(1)-(2))

D. Amendments to Appendix A for Display Panels

    Appendix A specifies the test procedure to determine energy 
consumption of walk-in display panels, which are not currently subject 
to any daily energy consumption performance standards but are subject 
to the prescriptive requirements at 10 CFR 431.306. The existing test 
procedure for walk-in display panels is very similar to that of walk-in 
doors in that it requires a U-factor test using NFRC 100-2010, which is 
used to determine the thermal conduction through the display panel and 
ultimately the total daily energy consumption. The existing display 
panel test procedure differs, however, from that of walk-in doors in 
that direct and indirect electrical energy consumption are not included 
in the test procedure.
    In the April 2022 NOPR, DOE proposed to apply all the test 
requirements proposed for determining display door conduction load and 
energy consumption to determining display panel conduction load and 
energy consumption, except for the provisions applicable to electrical 
components and PTO values. 87 FR 23920, 23943.
    Anthony agreed that the test procedure for display panels should be 
similar to the test procedure for display doors, but it disagreed with 
DOE's proposal that provisions applicable to electrical components and 
PTO values should be excluded from the test procedure for display 
panels. (Anthony, No. 31 at p. 7) Anthony stated that display panels 
can have heaters and lights. (Id.)
    DOE acknowledges Anthony's feedback regarding display panels; 
however, DOE does not currently have sufficient information on display 
panel electrical components and PTO values to adopt provisions for 
electrical components for display panels. DOE may do so in a future 
rulemaking, however at this time, DOE is adopting the changes to 
section III.C of appendix A for determining display panel conduction 
load and energy consumption as proposed in the April 2022 NOPR.

[[Page 28800]]

E. Amendments to Appendix B for Panels and Non-Display Doors

    The insulation R-value of walk-in non-display panels and non-
display doors is determined using appendix B. In the April 2022 NOPR, 
DOE proposed to modify appendix B to improve test representativeness 
and repeatability. 87 FR 23920, 23943. Specifically, DOE proposed to 
make the following revisions to appendix B: (1) reference the updated 
industry standard ASTM C518-17; (2) include more detailed provisions on 
measuring insulation thickness and test sample thickness; (3) provide 
additional guidance on determining parallelism and flatness of test 
specimen; and (4) reorganize appendix B so it is easier for 
stakeholders to follow as a step-by-step test procedure. Id.
    In response to the appendix B proposals, Bally commented that the 
proposed regulations will be burdensome for laboratories to conduct. 
(Bally, No. 40 at p. 4) DOE acknowledges Bally's comment; however, DOE 
has concluded that the proposed amendments would not be unduly 
burdensome and would improve test representativeness and repeatability 
as discussed in sections III.E.1 through III.E.5 of this document. Test 
procedure costs and impacts because of the adopted changes are further 
discussed in section III.K.2 of this document. DOE does not expect that 
the adopted changes to appendix B, discussed further, will alter 
measured R-values; therefore, no retesting or recertification is 
required.
    Additionally, AHRI commented generally that they would like to 
understand if display doors, non-display doors, and panels use the same 
calculation. (AHRI, No. 30 at p. 4) DOE defines each of these 
components separately (see subpart R of 10 CFR 431.302) and their 
respective test procedures are described in appendix A, and appendix B. 
The procedure for determining energy consumption of display doors 
begins at section 4.4 of appendix A. The procedure for determining 
energy consumption of non-display doors begins at section 4.5 of 
appendix A. Sections 4.4 and 4.5 of appendix A follow the same 
methodology of accounting for thermal conduction through the door 
(represented in the form of additional refrigeration system energy), 
the direct electrical energy consumption of electricity-consuming 
devices sited on the door, and the indirect electrical energy 
consumption of electricity-consuming devices represented in the form of 
additional refrigeration system energy consumption. Panels not 
classified as display panels follow the test procedure in appendix B, 
which determines the R-value of insulation for only the foam of the 
panel.
    Furthermore, DOE clarifies that in the following sections, the 
changes discussed are specifically in the context of walk-in panels; 
however, DOE notes that non-display doors are also subject to the 
prescriptive R-value requirement at 10 CFR 431.306(a)(3) and that the 
R-value for walk-in door insulation is determined using appendix B. The 
following sections describe the modifications that DOE is adopting in 
appendix B.
1. 24-Hour Testing Window
    As mentioned in the April 2022 NOPR, DOE is aware that the test 
specimen and conditioning instruction and example given in section 7.3 
of ASTM C518-04 and ASTM C518-17 conflict with the provision in section 
4.5 of the DOE test procedure at appendix B. The DOE test procedure 
requires testing be completed within 24 hours of specimens being cut 
for the purpose of testing, while ASTM C518-04 and ASTM C518-17 require 
that specimens be conditioned prior to testing based on material 
specifications, which could be longer than 24 hours. 87 FR 23920, 
23942.
    Bally commented that a cut sample should not be exposed to air for 
longer than 8 hours because foam samples become irreversibly de-
conditioned once removed from a panel. (Bally, No. 40 at pp. 3-4) Bally 
included a technical bulletin from 1984 that states that, in general, a 
1-inch cut section of foam can increase in K-factor about 5 to 10 
percent in a few days. (Bally, No. 40, Attachment 2) \30\
---------------------------------------------------------------------------

    \30\ The Bally comment included two supplemental attachments: 
Attachment 1, ``Solid and Opaque Eval,'' and Attachment 2, ``BTB--
Aging of Foam.'' DOE will reference as ``Attachment 1'' and 
``Attachment 2'' throughout this document. Both attachments are 
available on the docket.
---------------------------------------------------------------------------

    It is DOE's understanding that since the technical bulletin 
referenced by Bally was published, there have been changes to the 
blowing agents used in polyurethane foam, the most common foam 
insulation type used in walk-in panels. Additionally, no specific data 
on the change in K-factor beyond 8 hours was provided. Recent tests 
conducted by DOE demonstrate that there is no measurable difference in 
K-factor for specimens tested immediately after extraction from the 
complete panel as compared to specimens tested 24 hours after 
extraction from the complete panel. DOE has not evaluated changes to K-
factor of a test specimen beyond 24 hours of extraction from the panel. 
Given the existing technology on the market today, DOE believes 24 
hours is an appropriate limit that balances K-factor representativeness 
with test burden, and therefore DOE is maintaining the current 
requirement that testing be completed within 24 hours of cutting a test 
specimen from the envelope component. Correspondingly, DOE is not 
referencing Section 7.3 of ASTM C518-17 regarding specimen conditioning 
as part of its update to appendix B.
2. Total Insulation and Test Specimen Thickness
    Section 4.5 of appendix B currently requires that K-factor of a 1 
 0.1-inch sample of insulation be determined according to 
ASTM C518-04.
    To make the test procedure in appendix B more repeatable, DOE 
proposed in the April 2022 NOPR to include instructions for determining 
both the total insulation thickness as well as the test specimen 
insulation thickness prior to conducting the test to determine K-factor 
using ASTM C518-17, which is substantively the same as determining the 
K-factor according to ASTM C518-04. 87 FR 23920, 23944. DOE also 
proposed step-by-step instructions for specimen preparation, including 
detailed instructions of the number and locations of thickness and area 
measurements and from where the test specimen should be removed from 
the overall envelope component. Id. DOE proposed to require the 
following for determining the total thickness of the foam, 
tfoam, from which the final R-value is calculated:
     The thickness around the perimeter of the envelope 
component is determined as the average of at least 8 measurements taken 
around the perimeter that avoid the edge region.\31\
---------------------------------------------------------------------------

    \31\ Edge region means a region of the panel that is wide enough 
to encompass any framing members. If the panel contains framing 
members (e.g., a wood frame), then the width of the edge region must 
be as wide as any framing member plus an additional 2 in.  0.25 in. See section 3.1 of appendix B.
---------------------------------------------------------------------------

     The area of the entire envelope component is calculated as 
the width by the height of the envelope component.
     A sample is cut from the center of the envelope component 
relative to the envelope component's width and height. The specimen to 
be tested using ASTM C518-17 will be cut from the center sample.
     The thickness of the sample cut and removed from the 
center of the envelope component is determined as the average of at 
least 8 measurements, with at least 2 measurements taken in each 
quadrant.

[[Page 28801]]

     The area of the sample cut and removed from the center of 
the envelope component is determined as the width by the height of the 
cut sample.
     Any facers on the sample cut from the envelope component 
shall be removed while minimally disturbing the foam, and the thickness 
of each facer shall be the average of at least 4 measurements.
     The average total thickness of the foam shall then be 
determined by calculating an area-weighted average thickness of the 
complete envelope component less the thickness of the facers.

Id.
    For preparing and determining the thickness of the 1-inch test 
specimen, DOE proposed the following:
     A 1  0.1-inch-thick specimen shall be cut from 
the center of the cut envelope sample removed from the center of the 
envelope component.
     Prior to testing, the average of at least 9 thickness 
measurements at evenly spaced intervals around the test specimen shall 
be the thickness of the test specimen, L.
Id.
    In the April 2022 NOPR, DOE requested feedback on the proposed 
provisions relating to test specimen and total insulation thickness and 
test specimen preparation prior to conducting the ASTM C518-17 test. 
Anthony agreed with both of the proposals. (Anthony, No. 31 at p. 7) 
Bally referenced the EPCA calculation for R-value and recommended that 
R-value remain calculated with that formula. (Bally, No. 40 at p. 3) 
Bally commented that it believes the tolerance of 1  0.1 
inch is not necessary because the sample preparation process would need 
to be restarted, but a smaller sample could have been used to determine 
K-factor. (Bally, No. 40 at p. 4)
    In response to Bally's comment, DOE is not adopting any changes to 
the R-value formula; rather, DOE is providing additional instruction so 
that the inputs to the R-value formula, namely the K-factor, are 
determined in a consistent and more repeatable manner. At this time, 
DOE has determined that the 1  0.1 inch tolerance is still 
necessary to appropriately and consistently measure K-factor. 
Therefore, DOE is adopting the provisions outlined in the April 2022 
NOPR for determining test specimen and total thickness of insulation in 
appendix B.
3. Parallelism and Flatness
    The test procedure for determining R-value requires that the two 
surfaces of the tested sample that contact the hot plate assemblies (as 
defined in ASTM C518-04 and ASTM C518-17) maintain a flatness tolerance 
of 0.03 inches and maintain parallelism of one another with 
a tolerance of 0.03 inches.\32\ See section 4.5 of appendix 
B. As discussed in the April 2022 NOPR, the current test procedure does 
not provide direction to measure or calculate flatness and parallelism. 
DOE believes, however, that accurate and repeatable determination of a 
specimen's R-value requires the specimen under test to be both flat and 
parallel. 87 FR 23920, 23944.
---------------------------------------------------------------------------

    \32\ Maintaining a flatness tolerance means that no part of a 
given surface is more distant than the tolerance from the ``best-fit 
perfectly flat plane'' representing the surface. Maintaining 
parallelism tolerance means that the range of distances between the 
best-fit perfectly flat planes representing the two surfaces are no 
more than twice the tolerance (e.g., for square surfaces, the 
distance between the most distant corners of the perfectly flat 
planes minus the distance between the closest corners is no more 
than twice the tolerance).
---------------------------------------------------------------------------

    In the April 2022 NOPR, DOE proposed to include several steps for 
determining the parallelism and flatness of the test specimen in 
appendix B:
     Prior to determining the specimen thickness, the specimen 
would be placed on a flat surface and gravity used determine the 
specimen's position on the surface. As specified previously, a minimum 
of nine thickness measurements would be taken at equidistant positions 
on the specimen. These measurements would be associated with side 1 of 
the specimen.
     The least squares plane of side 1 is determined based on 
the height measurements taken. The theoretical height of the least 
squares plane is determined at each measurement location in the x and y 
(length and width) direction of the specimen.
     The difference at each measurement location between actual 
height measurement and theoretical height measurement based on the 
least squares plane is calculated. The maximum value minus the minimum 
value is the flatness associated with this side (side 1). For each side 
of the specimen to be considered flat, this value would need to be less 
than or equal to 0.03 inches.
     Flip the specimen so that side 1 is now on the flat 
surface and let gravity determine the specimen position on the surface. 
Repeat the steps above for side 2 of the specimen.
     To determine if each side of the specimen is parallel, the 
theoretical height at the four corners (i.e., at points (0,0), (0,12), 
(12,0), and (12,12)) of the specimen must be calculated using the least 
squares plane. The difference in the maximum and minimum heights would 
represent the parallelism of one side and would need to be less than or 
equal to 0.03 inches for the specimen to be considered parallel.

87 FR 23920, 23945.
    AHRI and Anthony agreed with the proposed provisions relating to 
determining parallelism and flatness of the test specimen. (AHRI, No. 
30 at p. 4; Anthony, No. 31 at p. 8) Bally stated that commercial 
devices used to measure K-factor using ASTM C518 have an internal check 
on flatness and parallelism so a sample that is out of tolerance will 
be flagged. (Bally, No. 40 at pp. 4-5)
    DOE acknowledges Bally's comment, however, it is DOE's 
understanding that not all manufacturers or laboratories use the same 
commercial device to measure K-factor. Regardless of the device used, a 
consistent procedure for determining parallelism and flatness is 
necessary. DOE is adopting the method for determining parallelism and 
flatness in appendix B as described in the April 2022 NOPR. 87 FR 
23920, 23945.
4. Insulation Aging
    The current test procedure for determining panel R-value does not 
account for insulation aging. ``Aging'' of foam insulation refers to 
how diffusion of blowing agents out of the foam and diffusion of air 
into the foam impacts thermal resistance of insulation materials. The 
gaseous blowing agents contained in the foam provide it with much of 
its insulating performance, represented by the R-value of the foam 
material. Because air has a lower insulating value than the blowing 
agents used in foam insulation, the increased ratio of air to blowing 
agent reduces the foam insulation performance, which reduces the R-
value of the foam material over time. The building industry uses long-
term thermal resistance (``LTTR'') to represent the R-value of foam 
material over its lifetime by describing the insulating performance 
changes due to diffusion over time. The presence of impermeable facers 
on a foam structure may delay the rate of aging or reduce the decrease 
in R-value when compared to a foam structure that is unfaced or has 
permeable facers. Blowing agents and temperature and humidity 
conditions may also affect the amount or rate of aging that occurs in a 
foam structure.
    In the April 2022 NOPR, DOE discussed its previous adoption and 
subsequent removal of a test procedure that considered aging of foam 
insulation. 87 FR 23920, 23945-23946. DOE rescinded the method that 
evaluated aging because of stakeholder concerns regarding test burden 
and the availability of laboratories to conduct the adopted test 
procedure. 79 FR 23788, 27405-27406. As such, DOE did

[[Page 28802]]

not propose to add test procedure provisions regarding aging in the 
April 2022 NOPR. 87 FR 23920, 23945-23946. DOE also did not propose to 
consider the effects of aging in assessment and enforcement testing 
because a recent study at Oak Ridge National Laboratory (``ORNL'') 
found the effects of foam insulation aging for panels sold with facers 
to be minimal when panel facers remain attached to the foam (i.e., when 
the panel remains intact).\33\ Id. In the April 2022 NOPR, DOE 
requested comment on other comparable data or studies of foam panel 
aging that are representative of the foam insulation, blowing agents, 
and panel construction currently used in the manufacture of walk-in 
panels. Id. DOE also requested comment on whether manufacturers have 
been certifying R-value at time of manufacture or after a period of 
aging. Id.
---------------------------------------------------------------------------

    \33\ A presentation on ORNL's study can be found online at 
www.osti.gov/biblio/1844325-impact-thermal-bridging-imperfections-agingeffective-value-walk-cooler-freezer-panels. DOE acknowledges 
that panels are shipped for assembly in walk-ins with the foam 
already in final chemical form between facers. Thus, the most 
applicable evaluation of change in insulation R-value over time is 
demonstrated by the red data points (labeled ``2'') for the foam 
that remained intact with the facers on slides 26 through 30 of 
ORNL's presentation.
---------------------------------------------------------------------------

    In response, AHRI suggested that any aging criteria should be based 
on the conditioning requirements in ASTM C518. (AHRI, No. 30 at p. 4) 
AHRI also stated that typical aging periods to ensure dimensional 
stability of finished foam has been reached vary between 14 and 28 
days. Id. Bally stated that it tests its foam without aging. (Bally, 
No. 40 at p. 5) RSG commented that it would like to limit the time 
between manufacture and testing as much as possible. (RSG, No. 41 at 
pp. 1, 11) RSG stated that it has conducted its own test, where it 
calculated R-value every 2 weeks for 6 months after manufacture; it 
found that R-value drops sharply at the beginning, followed by a slower 
rate of decline. (Id.)
    In response to AHRI's suggestion regarding aging criteria, DOE 
testing has shown that there is no measurable difference in K-factor 
for specimens tested immediately after extraction from the complete 
panel as compared to specimens tested 24 hours after extraction from 
the complete panel, even though it would be expected that aging of a 
thinner sample without facers would be more significant than a fully 
intact panel. Therefore, DOE expects the aging of an intact panel to be 
negligible after 24 hours.
    Bally's and RSG's comments suggest that manufacturers are rating R-
value without considering the effects of aging and would prefer to 
limit the amount of time between manufacture and test. As stated 
previously, DOE has found that there are minimal effects of foam 
insulation aging for panels sold with facers when panel facers remain 
attached to the foam. For assessment and enforcement testing conducted 
to support the enforcement of DOE's energy conservation standards, DOE 
is generally able to test samples within one to three months after 
receipt. The time lag from when the panel is manufactured and when 
testing is conducted at a laboratory is typically significantly shorter 
than that evaluated in the ORNL study. Therefore, DOE expects any 
reduction in R-value to be minimal from date of manufacture to 
assessment or enforcement test date. Additionally, walk-in panels 
received by DOE for assessment and enforcement testing are evaluated 
upon arrival to ensure that they are received intact (i.e., with 
facers) and undamaged, and testing of the specimen is completed within 
24 hours of sample removal from the panel, as specified in section 4.5 
of the DOE test procedure in appendix B. DOE does not expect any 
reduction in R-value within 24 hours of the sample being cut from the 
panel. Therefore, at this time, DOE will not consider insulation aging 
in the test procedure nor in the Department's assessment and 
enforcement testing based on the available data. DOE may consider 
additional data on this issue as it becomes available.
5. Overall Thermal Transmittance of Non-Display Panels
    The current test procedure for non-display panels does not measure 
the overall thermal transmittance of a walk-in panel. 87 FR 23920, 
23946. DOE previously adopted a test method for measuring overall 
thermal transmittance of a walk-in panel, including the impacts of 
thermal bridges \34\ and edge effects (e.g., due to structural 
materials and fixtures used to mount cam locks). 76 FR 21580. However, 
after receiving comments concerning test and cost burden and the lack 
of availability of laboratories to conduct the test procedure, DOE 
rescinded this portion of the walk-in panel test procedure. 79 FR 
27388, 27405-27406. Based on past concerns, DOE did not propose any 
provisions to evaluate overall thermal transmittance of non-display 
panels in the April 2022 NOPR. 87 FR 23920, 23946.
---------------------------------------------------------------------------

    \34\ Thermal bridging occurs when a more conductive material 
allows an easy pathway for heat flow across a thermal barrier.
---------------------------------------------------------------------------

    In response, the Efficiency Advocates encouraged DOE to investigate 
appropriate methods to capture the overall thermal transmittance of 
walk-in panels. (Efficiency Advocates, No. 37 at p. 4) DOE did not 
receive any other feedback on its proposal or specific suggestions on 
how to implement a procedure that would measure overall thermal 
transmittance while minimizing the test cost burdens previously 
identified.
    DOE continues to have the same concerns regarding test burden and 
lack of availability of test facilities to conduct any potential 
overall thermal transmittance testing of walk-in panels. Therefore, DOE 
is not including a test procedure in appendix B for determining overall 
thermal transmittance of non-display panels at this time.

F. Amendments to Appendix C for Refrigeration Systems

    Appendix C provides test procedures to determine the AWEF and net 
capacity of walk-in refrigeration systems. DOE does not expect that the 
adopted changes to appendix C will alter measured capacity values or 
AWEF. Therefore, DOE expects no retesting or recertification will be 
required. Rather, the revisions for appendix C address repeatability 
issues that DOE has observed through its testing of walk-in 
refrigeration systems.
    The following sections describe the modifications that DOE is 
making to appendix C, in this final rule.
1. Refrigeration Test Room Conditioning
    The DOE test procedure for walk-in refrigeration systems specifies 
temperature and/or humidity conditions for the test chambers. (See, 
e.g., Tables 3 through 16 of AHRI 1250-2009, which is incorporated by 
reference in the DOE test procedure.) Section C6.2 of AHRI 1250-2009 
requires that the environmental chambers ``be equipped with essential 
air handling units and controllers to process and maintain the enclosed 
air to any required test conditions.'' This requirement is also in 
section C5.2.2 of AHRI 1250-2020. However, DOE is aware that some test 
facilities may rely on the test unit to cool and dehumidify the test 
room. When the test unit is used to cool and dehumidify the test room, 
frost accumulation on the test unit's coils during pretest conditioning 
is possible and can affect the results of the capacity test. 87 FR 
23920, 23947. Section C5.1 of AHRI 1250-2020 states that the unit 
cooler under test may be used to aid in

[[Page 28803]]

achieving the required test chamber ambient temperatures prior to 
beginning a steady-state test but requires the unit under test to be 
free from frost before initiating steady-state testing. In the April 
2022 NOPR, DOE proposed to specify that for applicable system 
configurations (matched pairs, single-packaged systems, and unit 
coolers tested alone), the unit under test may be used to help achieve 
the required test chamber conditions prior to beginning any steady-
state test. 87 FR 23920, 23947. Additionally, DOE proposed to require a 
visual inspection of the test unit coils for frost before the steady-
state test begins. Id. 87 FR 23920, 23947. DOE requested comment on the 
proposed pretest coil inspection requirement and asked for feedback on 
current chamber conditioning practices within the industry. 87 FR 
23920, 23947.
    AHRI, HTPG, Hussmann, KeepRite, Lennox, and National Refrigeration 
disagreed with allowing the unit under test to condition the test room 
because it cannot sufficiently remove humidity from the room. (AHRI, 
No. 30 at p. 4; HTPG, No. 32 at p. 4; Hussmann, No. 38 at p. 3; 
KeepRite, No. 36 at p. 1; Lennox, No. 35 at pp. 2-3; National 
Refrigeration, No. 39 at p. 1) The same group of commenters also stated 
that the requirement for the unit to be ``free from frost'' is too 
subjective. (Id.) Hussmann mentioned that defrost could reduce the 
frost present, but that would result in a frosted-coil test instead of 
a dry-coil test. (Hussmann, No. 38 at p. 3) AHRI and Hussmann suggested 
that, if the unit under test is used to condition the test chamber, the 
unit's capacity be tested both before and after the test to ensure that 
the unit's capacity is not decreasing due to frost load. (AHRI, No. 30 
at pp. 4-5; Hussmann, No. 38 at p. 3) Lennox recommended that 
environmental chambers be equipped with air handlers to maintain test 
conditions. (Lennox, No. 35 at pp. 2-3) RSG agreed with the DOE's 
proposed inspection requirement. (RSG, No. 41 at p. 1)
2. DOE notes that the proposed test procedure allows the unit under 
test to aid in achieving the required test chamber conditions This 
implies that other conditioning equipment may be necessary and that the 
unit under test should never be the sole conditioner. In addition, DOE 
notes that the amendments to test procedure are in alignment with 
section C5 of AHRI 1250-2020, the most current industry test procedure. 
DOE has determined that a visual inspection is the most practical way 
to confirm that coils are free from frost and that while such an 
inspection may include subjective judgement about the presence of 
frost, it is better than no inspection at all. DOE has therefore 
determined that a visual inspection of the coils is sufficient. DOE 
also notes that the operating tolerances discussed in section III.F.5 
of this document, appendix C to subpart R of 10 CFR part 431, and AHRI 
420-2007 ensure that any significant impact of frost collection during 
a test would invalidate the test unless the unit capacity remains 
steady throughout a test.\35\ These requirements make the pre- and 
post-test measurement of capacity unnecessary. Therefore, DOE is 
adopting the test procedure as proposed in the April 2022 NOPR. DOE is 
adding the new requirement to appendix C, which also carries over to 
appendix C1. Temperature Measurement Requirements
---------------------------------------------------------------------------

    \35\ For dedicated condensing units and matched pairs, new mass 
flow operating tolerances are adopted as discussed in section 
III.F.5, and existing refrigerant temperature tolerances are 
specified in section 3.1.1 of appendix C to subpart R of 10 CFR part 
431. These two measurements would drift out of tolerance during a 
test if frost conditions were significantly affecting capacity 
measurements for such systems. Similarly, table C3 of AHRI 420-2007 
includes a refrigerant mass flow tolerance and table C4 of AHRI 420-
2007 includes inlet and outlet saturation temperature operating 
tolerances. These measurements would drift out of tolerance during a 
test if frost conditions were significantly affecting capacity 
measurements of unit coolers tested alone.
---------------------------------------------------------------------------

a. Suction Line Temperature Measurement
    The current DOE test procedure requires measuring refrigerant 
temperature entering or leaving the unit cooler using either 
thermometer wells or immersed sensors to determine refrigerant enthalpy 
as part of the capacity measurement for matched pairs and unit coolers 
tested alone (see 10 CFR part 431, subpart R, appendix C, section 
3.2.1). The capacity determination for dedicated condensing units 
tested alone is based on the refrigerant conditions leaving the 
condensing unit and standardized conditions leaving the unit cooler, as 
specified in section 3.4.2.1 of appendix C. In the April 2022 NOPR, DOE 
proposed to clarify that, when testing dedicated condensing units, 
thermometer wells or immersed sensors can be used only at the 
condensing unit liquid outlet and are not required to be used for the 
suction line. 87 FR 23920, 23947.
    AHRI, KeepRite, Lennox, National Refrigeration, and HTPG all 
commented that they do not support the proposal to forgo temperature 
measuring requirements for the suction line when testing dedicated 
condensing units. (AHRI, No. 30 at p. 5; KeepRite, No. 36 at p. 1; 
Lennox, No. 35 at p. 3; National Refrigeration, No. 39 at p. 1; HTPG, 
No. 32 at p. 4) AHRI also stated that legacy calculation and simulation 
systems use existing temperature measurements of the suction discharge. 
(AHRI, No. 30 at p. 5)
    DOE acknowledges that existing systems and calculations may depend 
on suction line temperature measurements. For this reason, DOE retracts 
its proposal from the April 2022 NOPR and in this final rule maintains 
the requirements for thermometer wells or immersed sensors for both the 
suction and liquid lines when testing dedicated condensing units alone.
    AHRI-Wine also commented that wine cellar manufacturers are 
concerned that the wells are not large enough for temperature 
measurements. (AHRI-Wine, No. 30 at p. 2) DOE notes that thermometer 
wells are required in the current DOE test procedure for temperature 
measurement. DOE addresses these concerns in the remainder of this 
section.
b. Surface-Mount Temperature Measurement Allowances for Small Diameter 
Tubing
    As mentioned in the April 2022 NOPR, DOE has found that 
implementing the current thermometer well requirement for refrigerant 
lines with an outer diameter of 1-2 inch or less can restrict the 
refrigerant flow and thus affect temperature measurements. To rectify 
this issue and to ensure that all walk-in refrigeration systems can be 
tested according to the DOE test procedure, DOE proposed allowing an 
alternative approach when the refrigerant line tubing diameter is 1-2 
inch or less, in which the temperature measurement would be made using 
two surface-mounted measuring instruments with a minimum accuracy of 
0.5 [deg]F, which would be averaged to obtain the reading. 
Additionally, DOE proposed that the two measuring instruments must be 
mounted on the pipe separated by 180 degrees around the refrigerant 
tube circumference. To ensure

[[Page 28804]]

measurements are not affected by changes in ambient temperature, DOE 
proposed requiring use of 1-inch-thick insulation around the measuring 
instruments that extends 6 inches up- and downstream of the measurement 
locations. Where this technique is used to measure temperature at the 
expansion valve inlet, DOE proposed to require that the measurement be 
within 6 inches of the device.
    With respect to tube surface measurements, AHRI and KeepRite stated 
that the temperature measurements on the tube surface are not accurate 
enough, and that this measurement is too critical to allow this. (AHRI, 
No. 30 at p. 5; KeepRite, No. 36 at p. 1) AHRI and KeepRite also stated 
that a low-temperature reading resulting from surface-mounted 
temperature measurement devices could lead to bubbling upstream of the 
expansion valve, resulting in inflated AWEF values. (AHRI, No. 30 at p. 
5; KeepRite, No. 36 at p. 2) Lennox supported DOE's proposal to allow 
surface-mounted temperature sensors but encouraged DOE to work with 
industry to ensure the full scope of applications can be covered with 
these requirements. (Lennox, No. 35 at p. 3) Additionally, AHRI and 
KeepRite suggested allowing transition to a pipe large enough for a 
thermometer well. Id. National Refrigeration also recommended 
maintaining the thermometer well requirement for small diameter tubing 
and allowing for larger diameter tubing to accommodate thermometer 
wells. (National Refrigeration, No. 39 at p. 1) Regarding location of 
the temperature measurement, AHRI and KeepRite agreed with the 
allowance to locate the temperature sensor within 6 inches; however, 
they suggested that the test procedure should further clarify if the 
measurement is from the body of the expansion valve or the joint with 
the liquid line. (AHRI, No. 30 at p. 5; KeepRite, No. 36 at p. 2) 
KeepRite further suggested allowing the dual liquid temperature 
measurements to be further upstream in a thermometer well with a 
secondary surface measurement 6 inches from the expansion valve and 
with sufficient insulation such that the surface temperature reading 
does not differ by more than 2 [deg]F from the thermometer well 
measurements. (KeepRite, No. 36 at p. 2)
    Specific to the liquid line temperature measurement location, DOE 
clarifies that the measurement is from the center of the body of the 
expansion valve.
    AHRI-Wine and HTPG agreed with the proposal to allow two external 
temperature measurements for small diameter tubing. (AHRI-Wine, No. 30 
at p. 2; HTPG, No. 32 at p. 4)
    DOE acknowledges the concerns from stakeholders regarding the use 
of surface measurements and will consider data from industry on this 
issue in future rulemakings. DOE has conducted testing using the 
approach proposed in the April 2022 NOPR and has determined that the 
approach provides representative measurements and prevents bubbling. 
Therefore, DOE is adopting the surface mount temperature measurement 
test provisions as proposed in the April 2022 NOPR. These requirements 
will be added to appendix C, and will also carry over to appendix C1.
3. Hierarchy of Installation Instruction and Specified Refrigerant 
Conditions for Refrigerant Charging and Setting Refrigerant Conditions
    As discussed in the April 2022 NOPR, DOE is aware that sometimes 
multiple installation instructions may be available for a unit, and 
different test results could be obtained based on which instructions 
are used. 87 FR 23920, 23948. DOE proposed a hierarchy for installation 
instructions and setup of refrigerant conditions to improve test 
repeatability by indicating which manufacturer-specified conditions 
would be prioritized during setup.
    Setup conditions or instructions may be stamped on the unit 
nameplate or otherwise affixed to the unit, shipped with the unit, or 
available online. DOE has encountered walk-in refrigeration units for 
which these three sources of instruction provide different values or 
conflicting directions. To ensure consistent setup during testing, DOE 
proposed in the April 2022 NOPR that instructions or conditions stamped 
on or adhered to a test unit take precedence, followed by instructions 
shipped with the unit. Id. Because online instructions can be easily 
revised, DOE proposed that instructions or other setup information 
found online would not be used to set up the unit for testing.
    Furthermore, setting of refrigerant charge level or refrigerant 
conditions is a key aspect of setup of refrigeration systems, whether 
for field use or testing. In the April 2022 NOPR, DOE proposed that 
units be charged and set up at operating conditions specified in the 
test procedure (for outdoor refrigeration systems, DOE proposed use of 
operating condition A) based on the installation instructions, using 
the proposed hierarchy (i.e., prioritizing instructions stamped or 
adhered to unit over instructions included in a manual shipped with the 
unit). Id. In cases where instructions for refrigerant charging or 
refrigerant conditions are provided only online or not at all, DOE 
proposed that a generic charging approach be used instead. If the 
installation instructions specify operating conditions to set up the 
refrigerant charge or refrigerant conditions, those conditions would be 
used rather than the conditions specified in the test procedure. Id.
    DOE determined that in some cases, a manufacturer specifies a range 
of conditions for superheat,\36\ subcooling, and/or refrigerant 
pressure. In these instances, DOE proposed to treat the midpoint of 
that range as the target temperature/pressure, and a test condition 
tolerance would be applied to the parameter that is equal to half the 
range. For example, if a manufacturer specifies a target superheat of 5 
to 10 [deg]F, the target for test would be 7.5 [deg]F and the average 
value during operation at the setup operating conditions would have to 
be 7.5 [deg]F  2.5 [deg]F. Alternatively, installation 
instructions may specify a refrigerant condition value without a range 
or without indicated tolerances. In such cases, DOE proposed that 
standardized tolerances be applied as indicated in Table III.3. These 
tolerances depend on the kind of refrigerant expansion device used.
---------------------------------------------------------------------------

    \36\ Superheat is the difference between vapor-phase refrigerant 
temperature and the dew point corresponding to the pressure level.

[[Page 28805]]



    Table III.3--Test Condition Tolerances and Hierarchy for Refrigerant Charging and Setting of Refrigerant
                                                   Conditions
----------------------------------------------------------------------------------------------------------------
            Fixed orifice or capillary tube                                  Expansion valve
----------------------------------------------------------------------------------------------------------------
      Priority            Method           Tolerance           Priority            Method           Tolerance
----------------------------------------------------------------------------------------------------------------
1..................  Superheat.......  2.0   1..................  Subcooling......  10% of the
                                        [deg]F.                                                  target value;
                                                                                                 no less than
                                                                                                 0.5
                                                                                                 [deg]F, no more
                                                                                                 than 2.0
                                                                                                 [deg]F.
2..................  High Side         4.0   2..................  High Side         4.0
                      Pressure or       psi or 1.0                              Saturation        minus>1.0
                      Temperature.      [deg]F.                                Temperature.      [deg]F.
3..................  Low Side or       2.0   3..................  Superheat.......  2.0
                      Saturation        psi or 0.8
                                        [deg]F.
4..................  Low Side          2.0   4..................  Low Side          2.0
                      Temperature.      [deg]F.                                Pressure or       psi or 0.8
                                                                               Temperature.      [deg]F.
5..................  High Side         2.0   5..................  Approach          1.0
                      Temperature.      [deg]F.                                Temperature.      [deg]F.
6..................  Charge Weight...  2.0   6..................  Charge Weight...  0.5% or 1.0 oz.,
                                        oz..                                                     whichever is
                                                                                                 greater.
----------------------------------------------------------------------------------------------------------------

    DOE also notes that zeotropic \37\ refrigerants have become more 
common. When charging with such refrigerants (i.e., any 400 series 
refrigerant), DOE proposed that the refrigerant charged into the system 
must be in liquid form. 87 FR 23920, 23948. Charging a system in liquid 
form is standard practice for charging of such refrigerants because the 
concentrations of the components of the blend present in the vapor 
phase of the charging cylinder are often skewed from the intended 
concentrations of the refrigerant blend.
---------------------------------------------------------------------------

    \37\ A zeotropic refrigerant is a blend of two or more 
refrigerants that have different boiling points. Each refrigerant 
will evaporate and condense at different temperatures.
---------------------------------------------------------------------------

    If the installation instructions on the label affixed to (or 
shipped with) the unit do not provide instructions for setting 
subcooling or otherwise how to charge with refrigerant for a condensing 
unit tested alone or as part of a matched pair, DOE proposed requiring 
testing the unit in a way that is consistent with the DOE test 
procedure and the installation instructions and that also does not 
cause the unit to stop operating during testing, e.g., by shutoff by 
the high-pressure switch. DOE believes that such installation would be 
most representative of the way a technician would set up a system in 
the field if there were no refrigerant charge or subcooling 
instructions. 87 FR 23920, 23948.
    AHRI and Lennox commented that they agree with the hierarchy of 
charging methods, however, they recommended that DOE allow use of 
online documentation. (AHRI, No. 30 at p. 6; Lennox, No. 35 at p. 3) 
HTPG also suggested that electronic instructions be allowed in addition 
to paper. (HTPG, No. 32 at p. 5)
    As discussed previously, DOE proposed in the April 2022 NOPR not to 
permit online instruction manuals in part because they can be easily 
revised. In consideration of these stakeholder comments, DOE has 
determined to allow use of online instruction manuals, with certain 
restrictions. Firstly, online instructions can be used only if no 
instructions or conditions are stamped on or adhered to a test unit or 
shipped with the unit. Secondly, to prevent revision to online 
documentation once a unit has been shipped by the manufacturer, online 
instruction manuals must include a version number or version date on 
the unit label or in the documents that are packaged with the unit.
    In this final rule, DOE is amending the test procedure such that 
setup instructions or conditions stamped on or adhered to a test unit 
take precedence, followed by instructions shipped with the unit, 
followed by online instructions if the version number or date of the 
online instruction manual is referenced on the unit label or is 
included in documents that are packaged with the unit.
    AHRI and Lennox recommended that outdoor units should be charged 
for condition C, not condition A. (AHRI, No. 30 at p. 6; Lennox, No. 35 
at p. 4) DOE has considered the commentors' recommendations and 
validated this charging procedure through testing. DOE is therefore 
amending the test procedure such that units be charged and set up at 
operating conditions specified in the test procedure (for outdoor 
refrigeration systems, operating condition C) based on the installation 
instructions, using the hierarchy summarized in Table III.3 of this 
document. DOE notes that many outdoor condensing units achieve head 
pressure control that uses valves to ``flood'' the condenser with 
liquid refrigerant to maintain sufficiently high condensing temperature 
when outdoor air is cold. If such a condensing unit has insufficient 
charge, it will be more obvious during operation in condition C (where 
head pressure control is generally active) since more charge would be 
in the condenser during such operation under head pressure control. 
Hence, DOE concludes that charging in the C condition rather than the A 
condition is appropriate for dedicated condensing systems (dedicated 
condensing units, matched systems, and single-packaged dedicated 
systems) that use a flooded condenser design. DOE has encountered units 
that, when charged at the C condition, will not operate at the A 
condition with the same charge weight due to high pressure cut out. 
This suggests the possibility that following the charging instructions 
may lead to two different charge weights depending on the condition 
used for charging. DOE maintains that it is not representative of field 
operation to use different refrigerant charge weights for the two test 
conditions, since it is not expected that refrigerant charge would be 
adjusted as ambient temperature rises and falls for a dedicated 
condensing system in the field. As such, DOE is adopting test 
provisions such that if a dedicated condensing system is charged at the 
C condition but does not operate at the A condition due to excess 
charge causing high pressure cut out, then refrigerant charge shall be 
adjusted to the highest charge that allows operation at the A 
condition. To limit the test burden of determining this highest charge, 
the determination shall be subject to a stepwise charge adjustment. 
Specifically, refrigerant would be removed in increments of 4 ounces or 
5

[[Page 28806]]

percent of the system's receiver capacity, whichever is larger, until 
operation at the A condition is possible. All tests, including those at 
condition C, will then be performed with this refrigerant charge.
    DOE notes that when conducting the C condition test for a dedicated 
condensing system for which this charge removal has occurred as 
described above, it is possible that the refrigerant leaving the system 
no longer has measurable subcooling. If the measured subcooling of the 
refrigerant leaving the condenser is less than 0 [deg]F, its state 
cannot accurately be determined based on the measurement. The most 
direct way to determine the state of the refrigerant would be to 
provide additional cooling to the liquid line after it leaves the 
condensing unit using a flow of a fluid such as water such that the 
water mass flow and temperature rise would be measured and such that 
the refrigerant is subcooled downstream of this heat exchange. Such an 
approach would allow determination of the enthalpy at the condensing 
unit exit as the enthalpy of its subcooled downstream state plus the 
additional cooling provided divided by the mass flow. However, DOE has 
determined that such an approach would require a chilled water, a 
refrigerant water heat exchanger, a water flow meter, temperature 
sensors, and provisions for flow and temperature measurements to be 
captured by the data acquisition system. DOE has determined that this 
additional equipment and time required to set up the additional 
equipment represent an inappropriate increase in test burden. DOE has 
finalized the test procedure requiring that if the calculated 
subcooling at the condensing unit exit is less than 0 [deg]F, the 
liquid at this location will be assumed to be at saturated liquid 
conditions. DOE has determined that the departure from saturated 
conditions is likely to be small. Additionally, this change in 
calculation method would only take place at one of the three test 
points. These two factors would lead to very little, or no, influence 
over the final measured AWEF. Further, this would only be necessary 
when testing units using refrigerant enthalpy-based test methods.
    DOE notes that it is also possible for dedicated condensing systems 
to maintain condensing temperature for low ambient operating conditions 
using fan controls rather than condenser flooding. Units that use fan 
control to maintain condenser temperature would not require 
significantly more refrigerant charge when operating at the C condition 
compared to the A condition. However, the fan controls of these systems 
may cause instability in refrigerant conditions at the lower ambient 
temperatures at the C test condition. As such, DOE has determined that, 
for dedicated condensing systems that exclusively use fan controls to 
maintain condensing temperature at low ambient temperatures, charging 
at the A condition is more appropriate than charging such units at C 
condition. The refrigerant charging proposals in the April 2022 NOPR 
sought to minimize test burden while ensuring the repeatability and 
representativeness of walk-in refrigeration system testing. 
Stakeholders correctly pointed out that charging at the A test 
condition would not be representative for systems with flooded-
condenser head pressure control. Thus, the change to charging at the C 
test condition was necessary. However, DOE has determined through 
testing that it is possible that when such a system is charged under 
test condition C, it could fail to operate due to high pressure cutout 
when operating under test condition A. Therefore, in order to ensure 
that a valid test can be conducted, DOE is adding the additional 
provisions. DOE believes these amendments are consistent with the 
intent of proposed changes in the April 2022 NOPR while being 
responsive to stakeholder feedback. Hence, DOE concludes that charging 
in the C condition rather than the A condition is appropriate.
    HTPG stated that it agrees that the unit under test should be set 
up according to a hierarchy of conditions. HTPG further stated, 
however, that it was unclear on the rationale for the inclusion and 
priority of ``High Side Pressure or Saturation Temperature,'' ``Low 
Side Pressure or Saturation Temperature,'' ``Approach Temperature,'' 
and ``Charge Weight'' in Table III.3. (HTPG, No. 32 at p. 5) HTPG did 
not provide detail on why these parameters should not be included, or 
otherwise reprioritized, in the hierarchy. DOE has developed the 
hierarchy summarized in Table III.3 based on its own testing experience 
and has observed that these parameters are specified operating 
conditions for certain units. Through that testing DOE has determined 
that the priority and inclusion of the methods listed in Table III.3 
are appropriate.
    Lennox stated that hierarchies in tables 1 and 19 should specify 
dew vs. bubble point to remove confusion with high-glide refrigerants. 
(Lennox, No. 35 at p. 4) DOE interprets Lennox's comment to be in 
reference to Table III.3 in this document, which in the proposed 
regulatory text was table 1 of appendix C (see 87 FR 23290, 24000-
24001) and table 19 of appendix C1, respectively (see 87 FR 23920, 
24021). DOE acknowledges that the proposed test procedure hierarchy did 
not clarify whether the dew or the bubble point should be used when the 
saturation point is specified. However, this should be addressed in the 
manufacturer's installation instructions, not specified by the test 
procedure. To clarify the intent in the hierarchy, DOE is adding a note 
in table 1 of appendix C and table 19 of appendix C1 to indicate that 
saturation temperature can refer to either bubble or dew point 
calculated based on a measured pressure, or a coil measurement, as 
specified by the installation instructions. DOE is adopting this 
clarification in this final rule.
    AHRI, on behalf of wine cellar manufacturers, KeepRite, and 
National Refrigeration agreed with the charging hierarchy. (AHRI-Wine, 
No. 30 at p. 2; KeepRite, No. 36 at p. 2; National Refrigeration, No. 
39 at p. 1)
    DOE received no comment on the remaining proposals discussed in 
this section. In this final rule, DOE is adopting the testing hierarchy 
instructions proposed in the April 2022 NOPR into appendix C, and will 
also carry these provisions over to appendix C1.
a. Dedicated Condensing Unit Charging Instructions
    For dedicated condensing units tested alone, subcooling is the 
primary setup condition. In the April 2022 NOPR, DOE proposed that if 
the dedicated condensing unit includes a receiver and the subcooling 
target leaving the condensing unit provided in the installation 
instructions cannot be met without fully filling the receiver, the 
subcooling target would be ignored. 87 FR 23920, 23948. Likewise, if 
the dedicated condensing unit does not include a receiver and the 
subcooling target leaving the condensing unit cannot be met without the 
unit cycling off on high pressure, the subcooling target would be 
ignored. Also, if no instructions for charging or for setting 
subcooling leaving the condensing unit are provided in the installation 
instructions, DOE proposed that the refrigeration system would be set 
up with a charge quantity and/or exit subcooling such that the unit 
operates during testing without shutdown (e.g., on a high-pressure 
switch) and operation of the unit is otherwise consistent with the 
requirements of the test procedure and the installation instructions.

[[Page 28807]]

    DOE received no comments in response to the proposals discussed in 
this section. In this final rule, DOE is adopting the dedicated 
condensing unit charging instructions proposed in the April 2022 NOPR 
into appendix C, and will also carry these provisions over to appendix 
C1.
b. Unit Cooler Setup Instructions
    For unit coolers tested alone, superheat is the primary setup 
condition. Most WICF refrigeration systems use either thermostatic or 
electronic expansion valves (``EEVs'') that respond either mechanically 
or through a controller to adjust valve position to control for 
superheat leaving the unit cooler. If the unit under test is shipped 
with an adjustable expansion device, DOE proposed in the April 2022 
NOPR that this would be the primary method to adjust superheat. 87 FR 
23920, 23948. However, DOE has encountered units with expansion devices 
that are not adjustable or where the expansion device does not provide 
a sufficient adjustment range to achieve the superheat target. If the 
expansion valve associated with the unit under test reaches its limit 
before the superheat target is met, the specified superheat may not be 
met within the specified tolerance. In this case, DOE proposed in the 
April 2022 NOPR that the expansion valve should be adjusted to obtain 
the closest match to the superheat target. Id. DOE has also encountered 
unit coolers with inappropriate expansion devices. When this occurs, 
DOE proposed in the April 2022 NOPR that any expansion device specified 
for use with the unit cooler in manufacturer literature may be used for 
the purposes of DOE testing. Id.
    In the April 2022 NOPR, DOE also proposed that an operating 
tolerance would not apply to superheat. Hence, if the system expansion 
valve control fluctuates (i.e., if so-called ``hunting'' occurs, in 
which the valve position, temperatures, and/or pressures are unsteady), 
it would not invalidate a test. 87 FR 23920, 23948-23949. However, if 
the fluctuation is so great that a valid test cannot be performed 
(i.e., any individual measurement of superheat during the test is zero 
or less), or if the operating tolerances for measurements that would be 
affected by expansion device hunting are exceeded (mass flow, pressure 
at the unit cooler exit, evaporator temperature difference),\38\ the 
test procedure would allow for deviation from the installation 
instructions. DOE proposed in the April 2022 NOPR that deviation from 
the installation instructions would be at the discretion of the test 
laboratory and could include replacing the expansion device with a 
different expansion device that does not need to be listed in 
installation instructions, adjusting the expansion device to provide an 
average superheat that is greater than the target superheat, or both. 
87 FR 23920, 23949.
---------------------------------------------------------------------------

    \38\ Evaporator temperature difference (TD) is the difference in 
temperature between the entering air and the refrigerant dew point 
of the exiting refrigerant.
---------------------------------------------------------------------------

    If the unit's installation instructions do not include setting 
superheat for a unit cooler tested alone or as part of a matched pair, 
DOE proposed in the April 2022 NOPR that the target superheat would be 
6.5 [deg]F, the same value required in such circumstances in AHRI 1250-
2020 (see Tables 16 and 17 of AHRI 1250-2020). Id.
    AHRI commented that unit cooler charging should be done based on 
the expansion valve controlled by the room, not the supplied expansion 
valve. (AHRI, No. 30 at p. 6) Lennox stated that it is industry 
practice to test unit coolers with EEVs, because use of these valves 
eliminates ``hunting'' and is more reliable. (Lennox, No. 35 at p. 4) 
HTPG stated that it disagrees with the proposal in the April 2022 NOPR 
that operating tolerance would not apply to superheat and believes it 
conflicts with AHRI 1250-2020, as well as Table III.3. (HTPG, No. 32 at 
p. 5) \39\
---------------------------------------------------------------------------

    \39\ DOE held an ex parte meeting with Lennox and HTPG to 
clarify these comments. See Docket No. EERE-2017-BT-TP-0010-0043.
---------------------------------------------------------------------------

    After consideration, DOE has determined that using the expansion 
valve supplied with the unit cooler is most appropriate for testing 
because it most closely represents field performance. DOE notes that 
the expansion device provided with the unit cooler or specified in the 
unit cooler installation instructions may result in hunting behavior 
and may fluctuate outside the specified tolerances for superheat. 
Nevertheless, these results are expected to be more representative of 
field performance than using a laboratory controlled EEV that provides 
steady operation. As discussed in the preceding paragraphs, the amended 
test procedure provides test laboratories with alternatives if the 
expansion devices shipped with the unit, or specified in the 
installation instructions, result in hunting that interferes with test 
measurement tolerances.
    DOE is aware that industry test practices are not currently 
consistent with this approach. As such, DOE recognizes that testing 
unit coolers with the expansion device shipped with the unit may 
require manufacturers to retest and recertify their unit cooler basic 
models. DOE is therefore not adopting the unit cooler expansion device 
requirements proposed in the April 2022 NOPR in appendix C. DOE is 
instead adopting those provisions only in appendix C1, which would be 
required for demonstrating compliance with any future amended WICF 
energy conservation standards. Manufacturers would therefore have 
additional time to retest and recertify unit cooler basic models 
impacted by these requirements.
c. Single-Packaged Dedicated System Setup and Charging Instructions
    DOE has identified multiple setup issues while testing single-
packaged dedicated systems. Compared to split refrigeration 
systems,\40\ single-packaged dedicated systems have less adjustment 
flexibility due to lack of controls. Additionally, while many single-
packaged dedicated systems are marketed as ``fully charged,'' DOE has 
found that many of its test units were undercharged.
---------------------------------------------------------------------------

    \40\ ``Split refrigeration systems'' refer to systems made up of 
a condensing unit and a unit cooler that are connected by 
refrigerant lines and are not contained in a single housing. Split 
refrigeration systems could be field-matched condensing units and 
unit coolers or condensing units and unit coolers sold as matched 
pairs.
---------------------------------------------------------------------------

    In the April 2022 NOPR, DOE proposed that one or more pressure 
gauges (depending on the number of conditions that require a pressure 
measurement for validation) should be installed during setup according 
to the manufacturer's installation instructions to evaluate the charge 
of the unit under test and to accurately measure setup conditions. 87 
FR 23920, 23949. The location of the pressure gauge(s) would depend on 
the test setup conditions given in the installation instructions. If 
charging is based on subcooling or liquid pressure, DOE proposed that 
the pressure gauge(s) would be installed at the service valve of the 
liquid line. If charging is based on superheat, low side pressure, or a 
corresponding saturation temperature or dew point temperature, DOE 
proposed that the pressure gauge(s) would be placed in the suction 
line. 87 FR 23920, 23949.
    DOE is aware that installation instructions for some single-
packaged dedicated systems recommend against installing charging ports; 
however, DOE has observed through testing that some such units that 
recommend against installing charging ports do not operate once 
installed due to high- or low-pressure compressor cut off, which is 
often a symptom of under- or over-charging or refrigerant loss. These 
units are representative of what a contractor

[[Page 28808]]

would encounter when installing a walk-in single-packaged dedicated 
system in the field. Therefore, in cases where a unit under test is not 
operating due to high- or low-pressure compressor cut off, DOE proposed 
in the April 2022 NOPR that a charging port should be installed, the 
unit should be evacuated, and the nameplate charge should be added. 87 
FR 23920, 23949. This approach would eliminate under- or over-charging 
of the unit which would address compressor cut off.
    DOE received no comments in response to the proposals in this 
section. In this final rule, DOE is adopting the single-packaged 
dedicated system setup instructions proposed in the April 2022 NOPR 
into appendix C, and will also carry these provisions over to appendix 
C1.
d. Hierarchy of Setup Conditions if Manufacturer-Specified Setup 
Conditions Cannot Be Met
    In DOE's experience, even when all the previously discussed 
measures are implemented during test setup, some manufacturer-specified 
setup conditions may not be met. In this case, DOE proposed in the 
April 2022 NOPR that the unit under test be set up according to a 
hierarchy of conditions like those used for central air-conditioning 
systems and heat pumps. 87 FR 23920, 23949. First, the installation 
instruction hierarchy previously discussed in section III.F.3 would be 
applied. Specifically, if a refrigerant-related setup instruction in 
the installation instructions affixed to the unit and a different 
instruction in the installation instructions shipped with the unit 
cannot both be achieved within tolerance, the instruction on the label 
takes precedence. Further, if multiple instructions within the relevant 
installation instructions cannot be met, the proposed hierarchy 
outlined in Table III.3 would be applied. The highest priority 
condition that can be satisfied, based on Table III.3, would need to be 
met, depending on what kind of expansion device the system uses. This 
approach would ensure that units are set up consistently across testing 
facilities, ensuring more consistent results.
    DOE received no comments in response to this proposal. In this 
final rule, DOE is adopting the hierarchy of setup conditions proposed 
in the April 2022 NOPR into appendix C, and will also carry these 
provisions over to appendix C1.
4. Subcooling Requirement for Mass Flow Meters
    Section C3.4.5 of AHRI 1250-2009 requires that refrigerant be 
subcooled to at least 3 [deg]F and that bubbles should not be visible 
in a sight glass immediately downstream of the mass flow meter. Section 
3.2.3 of appendix C allows use of the sight glass and a temperature 
sensor located on the tube surface under the insulation to verify 
sufficient subcooling. DOE testing has shown that even when the 
subcooling requirement is met downstream of the mass flow meter, the 
liquid temperature can be warmer upstream. This difference results in 
less subcooling, and mass flow measurements may not provide capacity 
within the required tolerances (i.e., within 5 percent of each other 
\41\ as required by section C8.5.3 of AHRI 1250-2009). 87 FR 23920, 
23950. In the April 2022 NOPR, DOE proposed to include additional 
instruction to section 3.2.3 of appendix C, to ensure fully liquid flow 
at the mass flow meter. Id.
---------------------------------------------------------------------------

    \41\ Section C8.5.3 of AHRI 1250-2009 requires that the two 
refrigerant-side gross capacities calculated based on the two sets 
of independent temperature, pressure, and mass flow measurements are 
within 5 percent of each other to ensure adequate subcooling. In the 
absence of adequate subcooling, the two refrigerant-side gross 
capacities may not be within 5 percent of each other due to 
disagreement in the mass flow readings.
---------------------------------------------------------------------------

    First, DOE proposed that the 3 [deg]F subcooling requirement be 
applied at a location dependent on the location of the liquid-line mass 
flow meters. Id. Specifically, the proposed requirement applies 
downstream of any mass flow meter located in the chamber that contains 
the condensing unit under test, consistent with AHRI 1250-2009. 
However, for mass flow meters located in the chamber that contains the 
unit cooler under test, subcooling would need to be verified upstream. 
In the April 2022 NOPR, DOE requested comments on its proposal to 
clarify the location where the 3 [deg]F subcooling requirement would 
apply. Id.
    AHRI stated that the proposal to clarify the location where the 3 
[deg]F subcooling applies may be sufficient in most, but not all, 
cases. (AHRI, No. 30 at p. 6) AHRI, KeepRite, and National 
Refrigeration recommended measuring temperature before and after the 
mass flow meter and calculating subcooling using the higher of the two 
temperatures with the pressure downstream of the meter to guarantee 
fully liquid flow. (AHRI, No. 30 at p. 6; KeepRite, No. 36 at p. 2; 
National Refrigeration, No. 39 at p. 2)
    HTPG recommended insulating the flow meter and line set to 
guarantee fully liquid flow. (HTPG, No. 32 at p. 5) HTPG also 
recommended that for dedicated condensing unit testing, the temperature 
measurement should be made before the flow meter inlet and for unit 
cooler testing, temperature measurement should be taken after the flow 
meter outlet. Id.
    Lennox and RSG agreed with DOE's proposal to clarify the subcooling 
condition measurement location. (Lennox, No. 35 at p. 4; RSG, No. 41 at 
p. 2)
    DOE notes that, assuming the mass flow meters are in the same room 
as the dedicated condensing unit, insulating the flow meter and line 
set may or may not help ensure fully liquid flow, depending on whether 
the temperature surrounding the line set and flow meter are higher or 
lower than the liquid temperature. DOE agrees that HTPG's 
recommendation for measuring the subcooling before and after the mass 
flow meters may provide a more rigorous approach for ensuring adequate 
subcooling throughout the flow meter than the procedure proposed by DOE 
in the April 2022 NOPR. However, during testing, DOE has found that the 
subcooling measurement locations proposed in the April 2022 NOPR ensure 
adequate subcooling through the mass flow meters with reduced test 
burden. Therefore, DOE is adopting the subcooling measurement locations 
as proposed in the April 2022 NOPR. DOE is adding the new requirements 
to appendix C, and will also carry these provisions over to appendix 
C1.
    Second, DOE proposed that active cooling of the liquid line may be 
used to achieve the required subcooling, because the subcooling at the 
mass flow meter outlet may not meet the 3 [deg]F requirement when the 
subcooling at the condensing unit exit is within tolerance of its 
target. However, DOE also proposed requiring that if active cooling is 
done when testing a matched pair (not including single-packaged 
dedicated systems), the temperature also must be measured upstream of 
the location where cooling is provided, and the temperature used to 
calculate the enthalpy of the refrigerant entering the unit cooler be 
increased by the difference between the upstream and downstream 
measurements. DOE proposed this adjustment so that active cooling of 
the liquid to obtain a mass flow measurement does not provide a non-
representative boost in calculated cooling capacity.
    In the April 2022 NOPR, DOE sought comment on its active subcooling 
and capacity calculation adjustment proposals. 87 FR 23920, 23950. In 
response, AHRI and KeepRite recommended adjusting test results for

[[Page 28809]]

active cooling based on suction pressure when testing matched pairs. 
(AHRI, No. 30 at p. 6; KeepRite, No. 36 at p. 2) KeepRite additionally 
stated that active subcooling should be constrained to prevent 
excessive subcooling and to obtain consistent results. (KeepRite, No. 
36 at p. 2) KeepRite also recommended additional testing to determine 
best practices for an active subcooling system and presented some 
possible best practices. (KeepRite, No. 36 at p. 3) RSG agreed with 
DOE's proposal to require adjustment of the measured unit cooler for 
active cooling. (RSG, No. 41 at p. 2)
    DOE acknowledges these comments and is making the following 
adjustments to the final test procedure to address stakeholder 
concerns. Instead of requiring an enthalpy adjustment if active 
subcooling is used, DOE is requiring that, if active subcooling is 
used, the line must be reheated such that the refrigerant is at the 
same temperature as it was upstream of the active subcooling device. 
This approach allows recording of an accurate mass flow measurement 
with no impact on the measured capacity of the unit under test. DOE is 
adopting the rest of the test procedures allowing active subcooling as 
proposed in the April 2022 NOPR. DOE is adding the new requirements to 
appendix C, and will also carry these provisions over to appendix C1.
5. Instrument Accuracy and Test Tolerances
    The current DOE test procedure references AHRI 1250-2009 for 
instrument accuracy and test tolerances with some modifications (see 10 
CFR part 431, subpart R, appendix C, section 3.1). As discussed in the 
April 2022 NOPR, some tolerances and instrumentation accuracy 
requirements in AHRI 1250-2020 are not consistent with the current DOE 
test procedure. 87 FR 23920, 23950. Specifically, DOE proposed to adopt 
the following changes from AHRI 1250-2020 into appendix C:
     Change the measurement accuracy for the temperature of air 
entering or leaving either the evaporator or condenser from  0.25 [deg]F.
     Replacing the ASHRAE 23.1 refrigerant mass flow operating 
tolerance of  1 percent of the quantity measured with an 
operating tolerance of 3 pounds per hour (``lb/h'') or 2 percent of the 
reading (whichever is greater).
    DOE did not receive comment on these proposals in the April 2022 
NOPR. In this final rule, DOE is adopting the proposed changes from 
AHRI 1250-2020 into appendix C. These changes are not expected to 
impact measured values. DOE is adding the new requirements to appendix 
C, and will also carry these provisions over to appendix C1.
6. CO2 Unit Coolers
    As discussed in the April 2022 NOPR, CO2 behaves 
differently than other refrigerants, as it has a critical temperature 
of 87.8 [deg]F.\42\ Ambient temperatures greater than 87.8 [deg]F are 
common, and the performance of many refrigeration and air-conditioning 
systems are tested using a 95 [deg]F ambient temperature, as indicated 
by the A test condition in Section 5 of AHRI 1250-2009 (and AHRI 1250-
2020). At temperatures greater than the critical temperature, the 
CO2 refrigerant is in a supercritical state. Since useful 
cooling is provided below the critical temperature, CO2 
cycles are said to be transcritical.
---------------------------------------------------------------------------

    \42\ All refrigerants have a ``critical pressure'' and an 
associated ``critical temperature'' above which liquid and vapor 
phases cannot coexist. Above this critical point, the refrigerant 
will be a gas and its temperature will increase or decrease as heat 
is added or removed.
---------------------------------------------------------------------------

    DOE has granted test procedure waivers to the manufacturers listed 
in Table III.1 of this document for certain basic models of walk-in 
refrigeration systems that use CO2 as a refrigerant. 
Manufacturers requesting a waiver from the DOE test procedure for 
CO2 unit coolers stated that the test conditions described 
in Tables 15 and 16 of AHRI 1250-2009, as incorporated by appendix C, 
with modification, cannot be achieved by, and are not consistent with 
the operation of, CO2 direct expansion unit coolers. The 
alternate test procedure provided in these waivers modifies the test 
condition values to reflect typical operating conditions for a 
transcritical \43\ CO2 booster system. Specifically, the 
waiver test procedures require that CO2 unit cooler testing 
is conducted at a liquid inlet saturation temperature of 38 [deg]F and 
a liquid inlet subcooling temperature of 5 [deg]F.
---------------------------------------------------------------------------

    \43\ CO2 refrigeration systems are transcritical 
because the high-temperature refrigerant that is cooled by ambient 
air is in a supercritical state, above the 87.8 [deg]F critical 
point temperature, above which the refrigerant cannot exist as 
separate vapor and liquid phases.
---------------------------------------------------------------------------

    In the April 2022 NOPR, DOE proposed to adopt in appendix C (and 
also in appendix C1), the alternate test conditions specified in the 
waivers that DOE granted for CO2 transcritical unit coolers 
for all CO2 unit coolers. Also, consistent with the waiver 
alternate test procedure, DOE proposed that the EER values in Table 17 
of AHRI 1250-2009 (or Table 18 of AHRI 1250-2020 for appendix C1) be 
used to determine the AWEF of all CO2 unit coolers. 87 FR 
23920, 23952. DOE requested comment on the appropriateness of 
traditional refrigerant compressor EER values for use in CO2 
unit cooler AWEF calculations. Id.
    AHRI, HTPG, Hussmann, Lennox, and National Refrigeration all agreed 
with the proposal. (AHRI, No. 30 at p. 7; HTPG, No. 32 at p. 5; 
Hussmann, No. 38 at p. 6; Lennox, No. 35 at p. 4; National 
Refrigeration, No. 39 at p. 2) DOE is adopting the test procedure as 
proposed in the April 2022 NOPR for CO2 unit coolers and 
adding the new requirements to appendix C, and will also carry these 
provisions over to appendix C1.
7. High-Temperature Unit Coolers
    As discussed in the April 2022 NOPR, DOE is aware of wine cellar 
(high-temperature) refrigeration systems that fall within the 
definition of ``walk-in'' but are unable to be tested under the current 
version of the walk-in test procedure due to their operation at a 
temperature range of 45 [deg]F to 65 [deg]F. 87 FR 23920, 23952. Most 
of the high-temperature refrigeration systems that DOE is aware of are 
either single-packaged dedicated systems or matched pairs. However, DOE 
has granted an interim waiver for high-temperature unit coolers that 
are distributed into commerce without a paired condensing system.\44\
---------------------------------------------------------------------------

    \44\ DOE granted an interim waiver to LRC Coil Company for 
specific basic models of unit cooler-only walk-in wine cellar 
refrigeration systems on August 26, 2021. 86 FR 47631. (See also 
EERE-2020-BT-WAV-0040, No. 1.) In reviewing another petition for 
waiver and interim waiver from Vinotheque for single-packaged system 
and matched pair system basic models (Vinotheque, EERE-2019-BT-WAV-
0038, No. 6), DOE noted that the manufacturer also offered unit 
cooler-only systems distributed without a paired condensing system.
---------------------------------------------------------------------------

    Under the current test procedure, these unit cooler-only models 
would be tested according to the provisions in the test procedure for 
unit coolers tested alone, for which the AWEF calculation requires an 
appropriate EER. DOE has determined that the EER values for medium- and 
low-temperature unit coolers tested alone are not appropriate for high-
temperature applications because this equipment operates with a 
different suction dew point temperature, and the dedicated condensing 
units typically paired with medium- and low-temperature units likely 
use different compressor designs, which would have different 
efficiencies.
    As discussed in the April 2022 NOPR, DOE calculated representative 
compressor EER levels for wine cellar walk-in unit coolers based on 
compressor performance data collected by DOE. 87 FR 23920, 23953. DOE 
used

[[Page 28810]]

the calculated compressor EER levels to develop different functions of 
EER for three distinct capacities, as summarized in Table III.4.

 Table III.4--EER Values for High-Temperature Compressors as a Function
         of Capacity for High-Temperature Refrigeration Systems
------------------------------------------------------------------------
            Capacity  (Btu/hr)                    EER  (Btu/(W-h))
------------------------------------------------------------------------
<10,000...................................  11.
10,000-19,999.............................  (0.0007 x Capacity) + 4.
20,000-36,000.............................  18.
------------------------------------------------------------------------

    The LRC Coil interim waiver includes additional test procedure 
provisions to obtain representations that are representative for high-
temperature unit coolers, including both testing requirements and AWEF 
calculation requirements. 86 FR 47631. These include provisions for 
testing ducted fan coil unit evaporator systems. 86 FR 47631, 47635.
    In the April 2022 NOPR, DOE proposed to include provisions for 
testing high-temperature unit coolers in appendix C. 87 FR 23920, 
23953. These provisions, consistent with the LRC Coil interim waiver, 
would include conditions for testing these unit coolers at high-
temperature refrigeration conditions, as well as the EER values in 
Table III.4 for calculation of AWEF. DOE also proposed to include these 
provisions in appendix C1 in the April 2022 NOPR. Id. AHRI-Wine agreed 
with DOE's inclusion of high-temperature unit cooler; however, they are 
concerned with the suitability of the test provisions and AWEF 
criteria. (AHRI-Wine, No. 30 at p. 2)
    DOE notes that high-temperature unit coolers have the same function 
as medium- and low-temperature unit coolers, however, their suction dew 
point temperature differs, and counterpart-dedicated condensing units 
may use high-temperature compressors designed for higher temperatures. 
Therefore, DOE has concluded that the same test procedure can be used 
for low-, medium- and high- temperature unit coolers, as long as the 
EER values presented in Table III.4 are used for high-temperature 
operation. After consideration of stakeholder comments, DOE is adopting 
the test procedure provisions for high-temperature unit coolers as 
proposed in the April 2022 NOPR. DOE is adding the new requirements to 
appendix C, and will also carry these provisions over to appendix C1.
    AHRI also stated that rating high-temperature unit coolers alone 
without a method to rate high-temperature dedicated condensing units 
disadvantages matched pairs and single-packaged dedicated systems. 
(AHRI, No. 30 at p. 2) DOE will evaluate standards for high-temperature 
equipment, including any appropriate equipment classes, in the ongoing 
walk-in energy conservation standards rule making. DOE's evaluation of 
the wine cellar market indicates that specific high-temperature 
dedicated condensing units are rarely, if ever, sold outside of 
matched-pair configurations. The dedicated condensing units DOE has 
encountered that are sold outside of a matched-pair configuration and 
that may be used in high-temperature applications are general-purpose 
condensing units often marketed for medium- and high-temperature, or 
only medium-temperature applications. Based on the definition of walk-
in coolers (i.e., medium-temperature refrigeration systems; see 10 CFR 
431.302), DOE has determined that the dedicated condensing units used 
for high-temperature applications are medium-temperature dedicated 
condensing units. As such, these units do not need to be certified for 
high-temperature applications but do need to be certified for medium-
temperature applications.

G. Establishing Appendix C1 for Refrigeration Systems

    In the April 2022 NOPR, DOE proposed to establish a new appendix C1 
to subpart R of part 431, which would be required to demonstrate 
compliance coincident with the compliance date of any amended energy 
conservation standards that DOE may promulgate as part of a separate 
standards rulemaking. 87 FR 23920, 23953.
    As the changes included in appendix C1 are expected to change 
measured values for walk-ins, DOE is establishing a new annual walk-in 
efficiency factor metric, AWEF2, that will replace the current metric, 
AWEF, once appendix C1 is required for use. In many cases, AWEF2 of a 
given refrigeration system will not be the same as AWEF. For any 
amended energy conservation standards that DOE may promulgate as part 
of a separate standards rulemaking, the standards will be set based on 
AWEF2.
    While AHRI 1250-2009 provides a method for determining off-cycle 
fan power, AHRI 1250-2020 includes off-cycle power measurement for 
additional auxiliary components (e.g., crankcase heaters, pan heaters, 
and controls). AHRI 1250-2020 also adds test procedures that allow for 
the testing of single-packaged dedicated systems and account for the 
thermal loss of these systems. Taking into consideration the additions 
just described, DOE has determined that AHRI 1250-2020 improves 
representativeness and expands the applicability of the walk-in 
refrigeration system test procedure. Additionally, DOE test procedures 
strive to be consistent with industry test methods. As AHRI 1250-2020 
is the most recent revision to the industry test procedure for walk-in 
refrigeration systems, it is the best representation of current 
industry testing practices. Therefore, DOE is incorporating AHRI 1250-
2020 by reference into its test procedure at appendix C1 for walk-in 
refrigeration systems.
    The test procedure changes that DOE is adopting as a part of 
appendix C1 are discussed in the following sections.
1. Off-Cycle Power Consumption
    For walk-in refrigeration systems, the term ``off-cycle'' refers to 
the period when the compressor is not running and defrost (if 
applicable) is not active. During off-cycle, unit cooler fans and other 
auxiliary equipment (crankcase heater, receiver heater, etc.) \45\ may 
typically run or cycle on and off, consuming energy. The DOE test 
procedure currently accounts for only unit cooler fan energy use during 
the off-cycle period. 10 CFR part 431, subpart R, appendix C, section 
3.3.3. Specifically, the current test procedure requires manufacturers 
to measure the integrated average off-cycle fan wattage \46\ for 
matched pairs and unit coolers tested alone. Dedicated condensing units 
tested alone use default fan energy values rather than tested values. 
10 CFR part 431, subpart R, appendix C, section 3.4.2.2. When 
calculating AWEF, the unit cooler fans are assumed to run at this 
average integrated wattage throughout the entire off-cycle duration. 
Id.
---------------------------------------------------------------------------

    \45\ A crankcase heater prevents refrigerant migration and 
mixing with the crankcase oil when the compressor is off by heating 
the crankcase of the compressor. A receiver heater warms refrigerant 
in the receiver to prevent flooded starts of the compressor and 
cycling on low pressure to reduce the potential for compressor 
damage. Both heaters are used for outdoor dedicated condensing units 
in colder climates.
    \46\ Fans using periodic stir cycles are tested at the greater 
of a 50 percent duty cycle or the manufacturer's default. Fans with 
two-, multi-, or adjustable-speed controls are tested at the greater 
of 50% fan speed or the manufacturer's default fan speed. Fans with 
no controls are tested at their single operating point. (See 10 CFR 
part 431, subpart R, appendix C, section 3.3.3.)
---------------------------------------------------------------------------

    In the April 2022 NOPR, DOE discussed the recommendation of the 
ASRAC Working Group (Docket No.

[[Page 28811]]

EERE-2015-BT-STD-0016, No. 56,\47\ Recommendation #6) to revise the 
off-cycle test procedure to account for all other components that 
consume energy during the off-cycle, such as pan heaters, crankcase 
heaters, and controls. 87 FR 23920, 23953. DOE noted that AHRI 1250-
2020 includes a method for determining energy consumption during off-
cycle for many of these components. Id.
---------------------------------------------------------------------------

    \47\ Appliance Standards and Rulemaking Federal Advisory 
Committee Refrigeration Systems Walk-in Coolers and Freezers Term 
Sheet, available at www.regulations.gov/document/EERE-2015-BT-STD-
0016-0056.
---------------------------------------------------------------------------

    DOE is adopting the off-cycle procedure in sections C3.5, C4.2, and 
Table C3 in AHRI 1250-2020 with some modifications. The following 
sections describe DOE's modifications to the off-cycle test method and 
metric in more detail.
a. Off-Cycle Test Duration and Repetition
    The current DOE test procedure references the 30-minute off-cycle 
test duration prescribed in section C3.6 of AHRI 1250-2009. AHRI 1250-
2020 was updated to include two off-cycle test durations: (1) 30 
minutes for evaporator fans and ancillary equipment with controls that 
are time-varying or respond to ambient or refrigerant temperatures 
(e.g., a crankcase heater or fan cycling control), and (2) 5 minutes 
for evaporator fans and ancillary equipment without such controls.
    DOE has concluded that these durations balance the need to minimize 
test burden with the need for an accurate and representative test 
method. In the April 2022 NOPR, DOE proposed to reference these test 
durations. 87 FR 23920, 23954.
    AHRI 1250-2020 also added two sets of test repetition requirements: 
one for evaporator fans and ancillary equipment with controls that are 
time-varying or respond to ambient or refrigerant temperatures (e.g., a 
crankcase heater or fan cycling control), and one for evaporator fans 
and ancillary equipment without such controls. For the former, AHRI 
1250-2020 requires that the off-cycle test for each applicable load 
point \48\ consists of three initial test cycles, with the potential 
for three supplemental cycles. As discussed in the April 2022 NOPR, 
AHRI 1250-2020 only requires the three supplemental tests if the 
integrated power of the first three cycles is not within 2 percent of 
the average of the first three cycles. 87 FR 23920, 23954. If the same 
variation occurs for the supplemental test cycles, then AHRI 1250-2020 
requires that off-cycle power be reported as the maximum value of all 
six integrated power readings. Alternatively, for equipment lacking 
evaporator fans and ancillary equipment controls, AHRI 1250-2020 
requires measuring integrated power over a single cycle. A summary of 
test durations and fan settings based on fan control configuration and 
ancillary equipment control configuration is listed in Table III.5.
---------------------------------------------------------------------------

    \48\ Off-cycle load points are discussed later in this section.

                               Table III.5--Off-Cycle Test Settings and Durations
----------------------------------------------------------------------------------------------------------------
                                       Ancillary equipment
     Fan control configuration        control configuration      Fan setting for test          Test duration
----------------------------------------------------------------------------------------------------------------
No Control.........................  No Control............  Default setting, as shipped  5 minutes.
No Control.........................  With Control..........  Default setting, as shipped  30 minutes.
User-Adjustable Speed Controls.....  No Control............  The greater of 50% fan       5 minutes.
                                                              speed or the
                                                              manufacturer's default fan
                                                              speed.
User-Adjustable Speed Controls.....  With Control..........  The greater of 50% fan       30 minutes.
                                                              speed or the
                                                              manufacturer's default fan
                                                              speed.
User-Adjustable Stir Cycles........  With or Without         The greater of a 50% duty    The greater of 30
                                      Control.                cycle or the manufacturer    minutes or three full
                                                              default..                    ``stir cycles.''
Non-User Adjustable Controls.......  With or Without         Default setting, as shipped  30 minutes.
                                      Control.
----------------------------------------------------------------------------------------------------------------

    DOE has concluded that the repetition requirements specified by 
AHRI 1250-2020 are adequate and not overly burdensome. If the variance 
is small among the first three cycles, then the testing burden is 
reduced by not requiring any more cycles. If variance exceeds 2 percent 
of the average when three additional cycles are taken, then the 
conservative approach is taken by reporting the maximum integrated 
power reading, and test burden is reduced by not requiring additional 
tests. In the April 2022 NOPR, DOE proposed to adopt the repetition 
requirements included in AHRI 1250-2020. 87 FR 23920, 23954.
    In response to the off-cycle test durations and repetitions 
proposed in the April 2022 NOPR, the Efficiency Advocates stated that 
they supported updating off-cycle testing to include a unit's total 
input wattage. (Efficiency Advocates, No. 37 at p. 1) Lennox supported 
DOE proposals regarding off-cycle test duration and repetition. 
(Lennox, No. 35 at pp. 4-5) In this final rule, DOE is adopting the 
off-cycle test duration and repetition test procedures as proposed.
b. Off-Cycle Operating Tolerances and Data Collection Rates
    In the April 2022 NOPR, DOE proposed to adopt Section C3.5 of AHRI 
1250-2020 to establish off-cycle data collection requirements in the 
DOE test procedure. 87 FR 23920, 23955. AHRI 1250-2020 excludes the 
first 10 minutes that follow the termination of the compressor on-cycle 
interval from the general operating tolerances (indoor/outdoor 
temperatures and power readings) established for the on-cycle steady 
state test because during this time period, the test room conditioning 
equipment is transitioning from steady state on-cycle operation into 
off-cycle operation.
    Additionally, AHRI 1250-2020 requires that the minimum data 
collection rate be increased (with respect to steady-state 
requirements) from 30 to 60 test readings per hour for temperature 
measurements and condensing unit electric power measurements, and from 
3 to 60 test readings per hour for unit cooler electric power 
measurements. AHRI 1250-2020 also requires that off-cycle power 
measurements be integrated and averaged over the recording interval 
with a sampling rate of no less than 1 second unless an integrating 
watt/hour meter is used.
    In response to the April 2022 NOPR, Lennox commented that it 
supports DOE's off-cycle power measurement proposals but requested 
clarification on

[[Page 28812]]

unit cooler ``steady-state ambient conditions,'' specifically whether 
35 [deg]F and -10 [deg]F for unit cooler refers to air entering dry-
bulb in Tables 16 and 17 of AHRI 1250-2020. (Lennox, No. 35 at pp. 4-5) 
DOE clarifies that the unit cooler ``steady-state ambient conditions'' 
of 35 [deg]F and -10 [deg]F refer to the entering air dry-bulb 
temperatures of medium-temperature and low-temperature unit coolers, 
respectively. DOE did not receive any additional comments on this topic 
and is adopting section C3.5 of AHRI 1250-2020 for off-cycle operating 
tolerances and data collection requirements, as proposed.
c. Off-Cycle Load Points
    Currently, the DOE test procedure specifies measuring off-cycle 
evaporator fan power and provides no ambient condition detail; however, 
DOE expects that the integrated power of ancillary equipment may vary 
with ambient conditions depending on the refrigeration system design. 
Consequently, in the April 2022 NOPR, DOE proposed that the off-cycle 
power test described in section III.G.1.a of this document be run at 
each steady-state ambient test condition as specified in Tables 4 
through 17 of AHRI 1250-2020. 87 FR 23920, 23955. Accordingly, DOE 
proposed that refrigeration systems with dedicated condensing units 
located indoors would evaluate off-cycle power at a single outdoor 
ambient condition (90 [deg]F dry-bulb), while systems with dedicated 
condensing units located outdoors would determine off-cycle power at 
three ambient conditions (95 [deg]F, 59 [deg]F, and 35 [deg]F dry-
bulb). The measured integrated off-cycle power results would then be 
used to calculate AWEF2, as described in the following section.
    In response to the April 2022 NOPR, KeepRite commented that the 
benefit from additional off-cycle power tests is minimal, capturing 
less than 1 percent of total system energy. (KeepRite, No. 36 at p. 3) 
DOE acknowledges that off-cycle power tests account for significantly 
less energy consumption than on-cycle tests. However, DOE's testing 
using the three ambient temperature off-cycle load points in AHRI 1250-
2020 has measured up to 60 percent more off-cycle power use than the 
off-cycle power measurements in the current test procedure. This result 
indicates that the current test procedure does not fully represent off-
cycle power use for walk-in refrigeration systems.
    HTPG disagreed with the additional off-cycle testing requirement 
proposed in the April 2022 NOPR (HTPG, No. 32 at p. 6) and stated that 
it would increase test burden. (HTPG, No. 32 at p. 8) AHRI-Wine stated 
that they expect the change related to off-cycle power measurement 
requirements will increase test burden. (AHRI-Wine, No. 30 at p. 3) DOE 
acknowledges that adopting the off-cycle power measurements in AHRI 
1250-2020 may incrementally increase test time. However, in its 
testing, DOE has found that conducting off-cycle power measurements 
accounts for less than 10 percent of the overall setup and test 
duration for walk-in refrigeration systems.
    Lennox stated that using a single condition to measure off-cycle 
power may not be sufficient for indoor matched systems. (Lennox, No. 35 
at p. 5) Lennox also recommended working with industry to establish 
running conditions for equipment that is not part of a matched pair. 
Id. DOE notes that the number and specified conditions of off-cycle 
tests correspond to the number and specified conditions of the 
refrigeration capacity tests that are run for each unit. Outdoor units 
have three capacity tests and three ambient conditions to represent the 
three ambient conditions that the unit would be exposed to, therefore 
they have three off-cycle tests. Indoor units have one capacity test at 
one ambient condition that the unit would be exposed to, therefore they 
have one off-cycle test. The ambient conditions inside the walk-in box 
do not fluctuate and therefore one ambient condition is representative 
for both on-cycle and off-cycle tests. DOE has concluded that this is 
the most appropriate approach to balance test procedure consistency and 
test burden.
    DOE is adopting the off-cycle test points for (1) the A test 
specified in AHRI 1250-2020 for fixed-capacity refrigerator and freezer 
matched-pair and dedicated condensing units located indoors, (2) the A, 
B, and C tests specified in AHRI 1250-2020 for refrigerator and freezer 
matched-pair and dedicated condensing units located outdoors, and (3) 
the A test specified in AHRI 1250-2020 for refrigerator and freezer 
unit coolers. DOE clarifies that a single off-cycle test is 
representative for both split-system unit coolers and indoor matched 
systems.
d. AWEF2 Calculations
    In the April 2022 NOPR, DOE proposed to adopt the off-cycle 
calculations in AHRI 1250-2020, which replace integrated off-cycle 
evaporator fan power with the combined integrated off-cycle power from 
the unit cooler and condensing unit in each equation. 87 FR 23920, 
23955. Additionally, DOE proposed to adopt the off-cycle calculations 
in AHRI 1250-2020, which replace integrated off-cycle fan power with 
integrated off-cycle power in the unit cooler equation. Id. This aspect 
of the unit cooler test method is consistent with the current method 
specified in appendix C to subpart R of 10 CFR part 431.
    For outdoor refrigeration systems, DOE proposed to deviate from the 
AHRI 1250-2020 calculations for off-cycle energy use in the April 2022 
NOPR. 87 FR 23920, 23955. DOE notes that the AHRI 1250-2020 equations 
for average refrigeration system total power input for bin temperature 
Tj, (e.g., Equation 13), do not appear to use off-cycle 
power values for the unit cooler and/or the condensing unit that vary 
with Tj. In fact, there are no equations providing the off-
cycle power for either component as a function of Tj in 
section 7 of AHRI 1250-2020, such as there are for net capacity and on-
cycle power input (e.g., Equations 14 through 17). Since the off-cycle 
power may vary as a function of outdoor temperature as discussed 
previously, DOE proposed in the April 2022 NOPR to adopt instructions 
for calculating off-cycle power as a function of outdoor temperature 
based on the measurements made at the three outdoor test condition 
temperatures. 87 FR 23920, 23955-23956.
    For condensing unit off-cycle power, DOE proposed in the April 2022 
NOPR to require that off-cycle power for Tj less than or 
equal to 35 [deg]F would be equal to the power measured for the test 
condition C off-cycle power test. 87 FR 23920, 23956. For Tj 
higher than 95 [deg]F, DOE proposed that that off-cycle power would be 
equal to the power measured for the test condition A off-cycle power 
test. Id. Between these two temperatures, DOE proposed that condensing 
unit off-cycle power would be determined based on the test condition B 
and C measurements when Tj is below 59 [deg]F, and based on 
the A and B measurements when it is above 59 [deg]F, similar to 
Equations 14 through 17 for on-cycle capacity and power in AHRI 1250-
2020. Id.
    For unit cooler off-cycle power, DOE proposed in the April 2022 
NOPR that the three unit cooler off-cycle power measurements taken when 
testing a matched-pair or single-packaged dedicated system would be 
averaged, and that the resulting average, with no dependence on 
Tj, would be used in the AWEF2 calculations. Id.
    DOE requested comment on its proposals to align the test procedures 
for appendix C1 with AHRI 1250-2020, except for the use of off-cycle 
power measurements in the AWEF2 calculations for dedicated condensing 
units, matched pairs, and single-

[[Page 28813]]

packaged dedicated systems intended for outdoor installation. Id. DOE 
also requested comment on its proposals to use three sets of unit 
cooler and outdoor dedicated condensing unit off-cycle measurements in 
the AWEF calculations. Id.
    In response, KeepRite stated that the AWEF2 calculations could be 
non-representative depending on what temperature the crankcase heater 
turns on and recommended an option for constant crankcase heater power 
below the 35 [deg]F test bins. (KeepRite, No. 36 at p. 3) DOE notes 
that the proposed AWEF2 calculations are incorporated from AHRI 1250-
2020. DOE notes that industry agreed to these calculations during the 
development of AHRI 1250-2020; therefore, DOE will not consider 
alternative calculations for representing off-cycle dedicated 
condensing unit power at this time.
    RSG recommended that DOE further define off-cycle unit cooler fan 
speed as either 50 percent of full speed or the factory low speed 
setting (if the low-speed setting is less than 50 percent and not 
adjustable by the end user). (RSG, No. 41 at p. 5) DOE notes that 
section 4.2 of Appendix C to AHRI 1250-2020 states that for variable-
speed unit cooler fan controls, the greater of 50 percent fan speed or 
the manufacturer's default fan speed shall be used for measuring off-
cycle fan energy. Since this is the test practice agreed on by 
industry, DOE is not allowing fan speeds of less than 50 percent for 
off-cycle unit cooler testing in this final rule.
    Lennox stated that the test procedure requires three measurements 
at different ambient conditions for matched-pair and single-packaged 
dedicated systems but does not explicitly state what to do for split-
system unit coolers. (Lennox, No. 35, at p. 5) Additionally, Lennox 
stated that a single test condition may not be sufficient for split-
system unit coolers. Id. DOE clarifies that for matched-pair and 
single-packaged dedicated systems located outdoors, there are three 
ambient conditions at which the dedicated condensing system is tested, 
therefore there are three corresponding off-cycle unit cooler power 
measurements. These off-cycle test conditions are specified in Tables 5 
and 9 of AHRI 1250-2020 for fixed-capacity matched pairs. AWEF2 is 
calculated as the average of these three measurements since these 
measurements should not vary with ambient temperature. For split-system 
unit coolers tested alone, there is no component exposed to outdoor 
ambient conditions, therefore there is only one condition at which the 
unit cooler is tested and one corresponding off-cycle power 
measurement. These conditions are listed in Tables 16 and 17 of AHRI 
1250-2020. As there is only one ambient condition at which the unit 
cooler is tested, DOE believes that the single off-cycle measurement is 
sufficient for split-system unit coolers.
    In this final rule, DOE is adopting the procedures as proposed in 
the April 2022 NOPR into appendix C1.
2. Single-Packaged Dedicated Systems
a. AHRI 1250-2020 Methods for Testing
    As discussed in the April 2022 NOPR, the Direct Expansion (``DX'') 
dual instrumentation method is impractical for testing single-packaged 
dedicated systems. 87 FR 23920, 23958. AHRI 1250-2020 expanded methods 
of test for single-packaged dedicated systems to include air enthalpy, 
calorimetry, and compressor calibration. Specifically, AHRI 1250-2020 
incorporates the following test procedures by reference:
    (1) Air enthalpy method: ASHRAE 37-2009, ``Methods of Testing for 
Rating Electrically Driven Unitary Air-Conditioning and Heat-Pump 
Equipment,'' and ANSI/ASHRAE 41.6-2014, ``Standard Method for Humidity 
Measurement'';
    (2) Calorimeter methods: ASHRAE 16-2016, ``Method of Testing for 
Rating Room Air Conditioners, Packaged Terminal Air Conditioners, and 
Packaged Terminal Heat Pumps for Cooling and Heating Capacity''; and
    (3) Compressor calibration methods: ASHRAE 37-2009, ``Methods of 
Testing for Rating Electrically Driven Unitary Air-Conditioning and 
Heat-Pump Equipment,'' and ANSI/ASHRAE 23.1- 2010, ``Methods of Testing 
for Rating the Performance of Positive Displacement Refrigerant 
Compressors and Condensing Units that Operate at Subcritical 
Temperatures of the Refrigerant.''
    AHRI 1250-2020 requires two simultaneous measurements of system 
capacity (i.e., a primary and a secondary method) for single-packaged 
dedicated systems, and section C9.2.1 of AHRI 1250-2020 requires that 
the measurements agree within 6 percent. Table C4 in AHRI 1250-2020 
specifies which test methods (calorimeter, air enthalpy, compressor 
calibration) qualify as primary and/or secondary methods. However, as 
summarized in Table III.6, DOE is adopting the method of test and the 
test hierarchy table in AHRI 1250-2020 with one modification--the 
addition of a single-packaged refrigerant enthalpy method. DOE is 
adopting this change to support testing of multi-circuit single-
packaged dedicated systems, which is discussed in detail in section 
III.G.2.f of this document.

   Table III.6--Single-Packaged System Test Methods and Test Hierarchy
------------------------------------------------------------------------
               Method of test                       Test hierarchy
------------------------------------------------------------------------
Balanced Ambient Indoor Calorimeter........  Primary.
Balanced Ambient Outdoor Calorimeter.......  Primary or Secondary.
Indoor Air Enthalpy........................  Primary or Secondary.
Indoor Room Calorimeter....................  Primary or Secondary.
Single-packaged Refrigerant Enthalpy \49\..  Secondary.
Outdoor Room Calorimeter...................  Secondary.
Outdoor Air Enthalpy.......................  Secondary.
Compressor Calibration.....................  Secondary.
------------------------------------------------------------------------

b. Waivers
---------------------------------------------------------------------------

    \49\ As described in section III.G.2.f of this document, this 
method of test does not apply to CO2 single-packaged 
units.
---------------------------------------------------------------------------

    As discussed in the April 2022 NOPR, DOE granted a waiver to Store 
It Cold for single-packaged dedicated systems on August 9, 2019. 87 FR 
23920, 23956. DOE also granted waivers to Air Innovations, CellarPro, 
Vinotemp, and Vinotheque for walk-in refrigeration systems used in wine 
cellar applications, where some of the basic models included in these 
waivers were single-packaged dedicated systems.\50\ The alternate test 
methods included in each of these waivers require the

[[Page 28814]]

specified basic models to be tested in accordance with the air enthalpy 
methods specified in ASHRAE 37-2009 for testing single-packaged 
dedicated systems, which is now referenced by AHRI 1250-2020. 
Additionally, DOE granted an interim waiver to RSG for multi-circuit 
single-packaged dedicated systems (``the RSG waiver''). 87 FR 43808. 
The alternate test method included in that waiver is further discussed 
in sections III.G.2.d through III.G.2.f of this document.
---------------------------------------------------------------------------

    \50\ Table III.1 lists the manufacturers that have received a 
test procedure waiver or interim waiver for walk-in refrigeration 
systems designed for wine cellar applications.
---------------------------------------------------------------------------

    In appendix C1, DOE is referencing the methods of test for single-
packaged dedicated systems from section C9 of AHRI 1250-2020, with some 
modifications. Since appendix C1 will be required on the compliance 
date of any amended energy conservation standards, were such standards 
to be adopted, the current test procedure waivers for specified single-
packaged basic models will expire on the compliance date of appendix 
C1.
c. Suitability of the Single-Packaged Test Methods in AHRI 1250-2020
    In the April 2022 NOPR, DOE discussed the suitability of the AHRI 
1250-2020 test methods for single-packaged dedicated systems. 87 FR 
23920, 23957. Specifically, DOE discussed stakeholder feedback from the 
June 2021 RFI that freezing of the calorimetry loop and the need for a 
pressure equalizing device on the test chamber are potential issues 
with the ASHRAE 16-2016 calorimeter method. DOE has tested multiple 
single-packaged dedicated systems at multiple labs and did not observe 
freezing of the calorimetry loop. Therefore, DOE has determined that 
the ASHRAE 16-2016 calorimetry methods are suitable for testing single-
packaged dedicated systems. Furthermore, DOE concluded that the 
equalizer device for calorimeter room testing, which is required in 
ASHRAE 16-2016, is not necessary for the testing of single-packaged 
dedicated systems. As a result, DOE did not propose to require an 
equalizer device for calorimeter room testing in the April 2022 NOPR. 
Id. Therefore, in the April 2022 NOPR, DOE proposed to adopt the ASHRAE 
16-2016 methods of test as referenced in AHRI 1250-2020 to provide 
flexibility to manufacturers.
    DOE further discussed in the April 2022 NOPR that its testing on 
single-packaged dedicated systems using the room calorimeter and air 
enthalpy methods as described in AHRI 1250-2020 appropriately accounted 
for the thermal losses that are typical for this equipment. Id. DOE 
additionally noted that while there may not be extensive experience 
applying these test methods to walk-in refrigeration systems, all the 
proposed test methods have been evaluated and are used extensively for 
testing other heating, ventilation, and air-conditioning (``HVAC'') 
equipment. Id. Therefore, in the April 2022 NOPR, DOE tentatively 
determined that these methods are representative of single-packaged 
dedicated system energy use and proposed to adopt the single-packaged 
dedicated system test procedure in AHRI 1250-2020 with the 
modifications outlined in sections III.G.2.d and III.G.2.e of this 
document. Id.
    In response to the April 2022 NOPR, the CA IOUs commented that they 
support DOE including a test method for single-packaged dedicated 
systems. (CA IOUs, No. 42 at p. 6) Based on DOE's experience testing 
this equipment and the comments received, DOE is adopting the test 
procedures for single-packaged dedicated systems in AHRI 1250-2020 as 
proposed in the April 2022 NOPR into appendix C1.
d. Single-Packaged Refrigerant Enthalpy Method
    In the April 2022 NOPR, DOE proposed to adopt a single-packaged 
refrigerant method similar to the alternate test procedure outlined in 
RSG's waiver request. 87 FR 23920, 23958. On July 22, 2022, DOE issued 
an interim waiver to RSG for testing single-packaged dedicated systems 
with multiple refrigeration circuits using a modified refrigerant 
enthalpy method. 87 FR 43808.
    As previously discussed, AHRI 1250-2020 includes four potential 
primary and six potential secondary test methods for testing single-
packaged dedicated systems (see Table C4 in AHRI 1250-2020). The 
refrigerant enthalpy method is not included in these lists. The 
procedure that DOE proposed to adopt in the April 2022 NOPR uses the 
refrigerant-side measurements of the DX calibrated box method in 
section C8 of AHRI 1250-2020 while simultaneously using one of the 
``primary'' methods listed in Table C4 in AHRI 1250-2020 for single-
packaged methods of test as an air-side measurement. The details of the 
primary test methods were discussed in the April 2022 NOPR. 87 FR 
23920, 23958.
    In the April 2022 NOPR, DOE requested comment on its proposed 
procedure for testing single-packaged dedicated systems. AHRI 
recommended allowing DX dual instrumentation testing, since requiring 
air-side enthalpy testing would impose considerable test burden on test 
labs that do not have air-side measurement capacity. (AHRI, No. 30 at 
p. 7) Lennox stated that it can support the proposed refrigerant 
enthalpy approach as a secondary approach but recommended that the DX 
dual instrumentation method be maintained as an option. (Lennox, No. 35 
at p. 5) Lennox also commented that requiring the air enthalpy test 
method would impose significant test burden. Id. In response to the 
recommendation by Lennox to maintain the DX dual instrumentation 
method, DOE's testing, in addition to the information received in the 
waivers for testing of single-packaged dedicated systems, indicates 
that the DX dual instrumentation method is inappropriate for single-
packaged units because the internal volume of the added liquid line and 
mass flow meters adds substantially to the required refrigerant charge, 
and the entire assembly adds substantial pressure drop.\51\ However, 
DOE notes that the DX dual instrumentation method continues to be an 
accurate test method for dedicated condensing units tested alone. 
Additionally, in response to Lennox's comment regarding the burden 
associated with the air enthalpy method, DOE has determined that the 
representativeness achieved through this method outweighs the 
additional burden.
---------------------------------------------------------------------------

    \51\ See Store It Cold Decision and Order, 84 FR 39286, 39287 
(Aug. 9, 2019).
---------------------------------------------------------------------------

    AHRI and Lennox commented that piercing a refrigeration system to 
use the refrigerant enthalpy as a secondary check may not duplicate the 
primary result. (AHRI, No. 30 at p. 7; Lennox, No. 35 at p. 5) HTPG 
disagreed with the proposal to use the refrigerant enthalpy test for 
single-packaged dedicated units, as they are critically charged and 
piercing their lines could affect measured capacity. (HTPG, No. 32 at 
p. 6) The proposed procedure requires a primary test to be completed 
before the system is pierced. The capacity measured from the primary 
test would be compared to the capacity measured from the secondary test 
to ensure that the capacity is not affected from piercing the 
refrigeration system. Based on its testing, DOE has determined that a 
secondary test that does not materially alter the system operation 
would duplicate, and serve as a check for, the primary test. DOE also 
notes that there are secondary test options provided in Table C4 of 
AHRI 1250-2020 that do not require piercing of the refrigerant lines.
    Lennox also stated that the refrigerant enthalpy test should be 
allowed to penetrate the system for the primary test since the 
secondary test would require the system to be penetrated. (Lennox, No. 
35 at p. 5) DOE interprets this comment to be a request to allow the DX

[[Page 28815]]

dual instrumentation test, or other refrigerant enthalpy tests, as a 
primary test for single-packaged dedicated systems. As discussed 
previously, DOE has concluded that the DX dual instrumentation test is 
not representative for single-packaged dedicated systems because it 
does not account for thermal losses. DOE reiterates that the purpose of 
the primary test, conducted prior to penetration of the refrigerant 
system, is to compare the primary and secondary results to ensure that 
the system is not affected from penetrating the liquid lines.
    AHRI-Wine stated that they do not support the proposed refrigerant 
enthalpy test procedure because they do not see an advantage unless the 
method is used in parallel with others. (AHRI-Wine, No. 30 at p. 3) DOE 
notes that the single-packaged refrigerant enthalpy test procedure 
would be used only as a secondary test when paired with one of the 
primary options provided in Table C4 of AHRI 1250-2020.
    RSG agreed with DOE's proposed test procedure. (RSG, No. 41 at p. 
2) DOE is adopting the single-packaged refrigerant enthalpy test method 
as a secondary test as proposed in the April 2022 NOPR into appendix 
C1.
e. Calibrated Box Method for Single-Packaged Dedicated Systems
    In the RSG waiver DOE allowed RSG to use a modified version of the 
calibrated box method. 87 FR 43808, 43813-43814. As discussed in the 
notification of interim waiver, the modified calibrated box method 
involves mounting the system on the calibrated box, like its 
installation on a walk-in for field use and exchanging air with the box 
interior to cool it. 87 FR 43808, 43812. The exterior of the calibrated 
box would be conditioned such that the air conditions entering the 
single-packaged dedicated system condenser match the specified targets. 
The warm condensing unit portion of the single-packaged dedicated 
system and its condenser discharge air may in some cases add to the 
thermal load imposed on the calibrated box. The interim waiver 
therefore provided additional optional test methods to quantify this 
additional thermal load on the calibrated box, and to adjust for it in 
the determination of system capacity. Determining the additional 
thermal load requires temperature sensors mounted on the box exterior 
surface for box calibration and box load determination, rather than 
measuring air temperature just outside the box (the approach described 
for the calibrated box method in section C8 of AHRI 1250-2020). Since 
the modified calibrated box method accounts for the thermal losses 
associated with single-packaged dedicated systems and is very similar 
to the indoor room calorimeter method, DOE tentatively determined in 
the RSG waiver that it would be appropriate for the calibrated box 
method to be a primary test method (i.e., the capacity determined from 
this method would be used for rating purposes) 87 FR 43808, 43812. DOE 
proposed to adopt the method described in the RSG waiver in the April 
2022 NOPR. Id. A full discussion of the test procedures proposed by RSG 
are discussed in the interim waiver notification. Id.
    As mentioned previously, DOE received no stakeholder comments on 
the RSG waiver. Therefore, DOE is adopting the test provisions outlined 
in the RSG waiver in addition to the test provisions for single-
packaged dedicated systems proposed in the April 2022 NOPR.
f. Multi-Circuit Single-Packaged Dedicated Systems
    As discussed in the April 2022 NOPR, neither the current DOE test 
procedure nor AHRI 1250-2020 provides a method for testing single-
packaged dedicated systems with multiple refrigeration circuits. As 
previously discussed, DOE granted RSG an interim waiver for testing 
multi-circuit single-packaged dedicated systems. 87 FR 43808. This test 
procedure is based on the single-packaged refrigerant enthalpy method 
discussed in section III.G.2.d of this document. The procedure is 
duplicated for each refrigeration circuit contained in the unit such 
that each circuit returns mass flow, enthalpy in, and enthalpy out 
values. The resultant mass flow and enthalpy values are used to 
calculate the gross refrigeration capacity for each circuit. Each 
circuit's gross capacity is then summed to determine the total capacity 
of the system.
    In the April 2022 NOPR, DOE tentatively determined that the 
alternate approach would provide a reasonable method for determining 
the capacity of multi-circuit single-packaged dedicated systems. 87 FR 
23920, 23958. However, DOE had also determined the approach may not 
adequately capture the heat loss associated with single-packaged 
dedicated systems; therefore, DOE proposed to adopt the test procedures 
in section C8 of AHRI 1250-2020 for testing single-packaged dedicated 
systems, with the additional requirement that the primary test would be 
an indoor air refrigeration capacity test where the allowable 
refrigeration capacity heat balance is 6 percent. Id.
    In response to the April 2022 NOPR, HTPG commented that it agreed 
with DOE's proposal for testing multi-circuit single-packaged dedicated 
systems. (HTPG, No. 32 at p. 6) DOE is adopting the test procedure as 
proposed in the April 2022 NOPR into appendix C1.
g. CO2 Single-Packaged Dedicated Systems
    As discussed in the April 2022 NOPR, the current DOE test procedure 
for single-packaged dedicated systems does not provide representative 
values for single-packaged dedicated systems that use CO2 as 
a refrigerant. 87 FR 23920, 23959. However, the single-packaged 
dedicated system test methods in AHRI 1250-2020 use air enthalpy 
measurements and do not require any refrigerant mass flow measurements. 
In the April 2022 NOPR, DOE proposed that single-packaged dedicated 
systems that use CO2 as a refrigerant be tested using the 
test methods for single-packaged dedicated systems outlined in AHRI 
1250-2020. Id.
    In response, HTPG stated that it agreed with DOE's proposal for the 
air enthalpy test procedure for CO2 single-packaged 
dedicated systems. (HTPG, No. 32 at p. 6) DOE is adopting the test as 
proposed in the April 2022 NOPR into appendix C1.
3. Detachable Single-Packaged Dedicated Systems
    As discussed in section III.A.2.g, DOE is aware of refrigeration 
systems that are installed with the evaporator unit exchanging air 
through the wall or ceiling of the walk-in, but with the condensing 
unit installed remotely and connected to the evaporator with 
refrigerant lines. DOE has defined this equipment as a ``detachable 
single-packaged dedicated system.'' Neither appendix C nor AHRI 1250-
2020 contain provisions for testing detachable single-packaged 
dedicated systems. DOE is aware that, currently, detachable single-
packaged dedicated systems may be tested either with the condensing 
unit and unit cooler housings separated or mounted adjacent to each 
other, the latter of which is the more common arrangement for single-
packaged dedicated systems. Testing in the latter arrangement would 
account for the heat loss of the evaporator installation, and any 
additional heat loss from the condensing unit being mounted to the 
evaporator unit; therefore, in the April 2022 NOPR, DOE proposed as 
part of the new appendix C1 and 10 CFR 429.53(a)(2)(i)(C) that 
detachable single-packaged dedicated systems would be tested using the 
test procedure for

[[Page 28816]]

single-packaged dedicated systems. 87 FR 23920, 23959.
    HTPG and Lennox agreed with the proposal. (HTPG, No. 32 at p. 6; 
Lennox, No. 35 at p. 5) AHRI, on behalf of wine cellar manufacturers 
stated that the proposal is sufficient. (AHRI-Wine, No. 30 at p. 4) RSG 
agreed with the proposal if the calibrated box method is included in 
allowable test methods. (RSG, No. 41 at p. 2) As discussed in section 
III.G.2.e, DOE is adopting the test provisions outlined in the interim 
waiver granted to RSG in July 2022. These include a calibrated box test 
procedure for single-packaged dedicated systems.
    AHRI stated that the current test procedure is sufficient. (AHRI, 
No. 30 at p. 8) DOE interprets this comment as AHRI stating that the DX 
dual instrumentation method is sufficient for detachable single-
packaged dedicated units. As discussed in section III.G.2.d, DOE's 
testing, in addition to information received in waivers for testing of 
single-packaged dedicated systems, indicates that the DX dual 
instrumentation method is inappropriate for single-packaged units.
    Since detachable single-packaged dedicated systems have thermal 
losses similar to those for single-packaged dedicated systems, DOE is 
adopting the test procedure for detachable single-packaged dedicated 
systems as proposed in the April 2022 NOPR (87 FR 23920, 23959) into 
appendix C1.
    AHRI-Wine also requested clarification for whether wine cellar 
manufacturers must test all configurations or the most common if 
multiple configurations apply to a single system. (AHRI-Wine, No. 30 at 
p. 2) The definition of ``detachable single-packaged dedicated system'' 
that DOE is adopting in this final rule states that it is a system that 
can be configured as either a split system or as a single-packaged 
dedicated system. Based on the procedure DOE is adopting, such a system 
would be tested as a single-packaged dedicated system.
4. Attached Split Systems
    As discussed in section III.A.2.f, DOE is aware of refrigeration 
systems that are sold as matched systems and permanently attached to 
each other with beams. In this final rule, DOE is defining these 
systems as ``attached split systems.'' DOE has confirmed through 
testing that these systems still experience some heat leakage when 
compared to traditionally installed systems that have the dedicated 
condensing unit and the unit cooler in separate housings. However, this 
heat leakage has not been studied extensively and DOE is aware that it 
may be difficult to calculate.
    DOE proposed in the April 2022 NOPR testing attached split systems 
as a matched pair using refrigerant enthalpy methods. 87 FR 23920, 
23959. HTPG agreed with the proposal. (HTPG, No. 32 at p. 7) In this 
final rule, DOE is adopting the test procedure as proposed in the April 
2022 NOPR into appendix C1 and 10 CFR 429.53(a)(2)(i)(D).
5. Systems for High-Temperature Freezer Applications
    As discussed in the April 2022 NOPR, DOE recognizes that testing 
high-temperature freezer refrigeration systems at a consistent test 
condition is important to ensure test procedure consistency and to 
provide comparable performance values in the market. 87 FR 23920, 
23961. DOE acknowledges that testing high-temperature freezer 
refrigeration systems at a temperature less than 35 [deg]F would be 
more representative of their actual energy use; however, it is not 
clear if the potential additional test burden justifies including an 
additional test condition for walk-in cooler refrigeration systems. 
Therefore, in the April 2022 NOPR, DOE determined that medium-
temperature dedicated condensing units used in high-temperature freezer 
applications would continue to be tested according to appendix C. Id.
    In response to the April 2022 NOPR, HTPG stated that it agreed with 
DOE continuing to test high-temperature freezers in accordance with 
appendix C. (HTPG, No. 32 at p. 7) The Efficiency Advocates encouraged 
DOE to establish a standardized rating temperature for high-temperature 
freezers that is below 35 [deg]F, since it is more characteristic of 
the temperature that these products operate between. (Efficiency 
Advocates, No. 37 at p. 3) As discussed in the April 2022 NOPR, DOE 
acknowledges that testing high-temperature freezer refrigeration 
systems at a temperature less than 35 [deg]F would be more 
representative of their actual energy use; however, doing so would 
require an additional test condition. At this time, DOE does not think 
the relatively small gain in representativeness that this additional 
test condition would provide justifies the additional test burden for 
evaluating the performance of walk-in cooler refrigeration systems. 
Therefore, DOE is maintaining its determination to keep testing systems 
for high-temperature freezer applications as medium-temperature 
systems.
6. Systems for High-Temperature Applications
    As discussed previously in section III.A.2.c, DOE is aware of wine 
cellar (high-temperature) refrigeration systems that fall within the 
definition of ``walk-in'' but operate at a temperature range of 45 
[deg]F to 65 [deg]F and, therefore, are incapable of being tested in a 
manner that would yield a representative average use cycle under the 
current version of the walk-in test procedure. DOE has granted waivers 
or interim waivers to the manufacturers listed in Table I.1 for an 
alternate test procedure for specific basic models of single-packaged 
dedicated systems, matched pair, and unit cooler-only high-temperature 
refrigeration systems.
    In the April 2022 NOPR, DOE proposed to include provisions for 
testing and rating high-temperature matched-pair systems that specify 
an air entering dry-bulb temperature of 55 [deg]F. 87 FR 23920, 23961. 
DOE also proposed to test high-temperature refrigeration systems that 
are single-packaged dedicated systems using one of the following 
methods, as specified in Table C4 of AHRI 1250-2020: indoor air 
enthalpy, outdoor air enthalpy, compressor calibration, indoor room 
calorimeter, outdoor room calorimeter, balanced ambient indoor 
calorimeter, or balanced ambient outdoor calorimeter. Id.
    In response to the April 2022 NOPR, the Efficiency Advocates 
commented that they support adding unique test procedures for high-
temperature walk-ins. (Efficiency Advocates, No. 37 at p. 2)
    The alternate test approach in the waivers requires that testing of 
ducted units be conducted at 50 percent of the maximum external static 
pressure (``ESP''), subject to a tolerance of -0.00/+0.05 in. wc.\52\ 
Consistent with the waivers that DOE has granted for high-temperature 
refrigeration systems, in the April 2022 NOPR DOE proposed that testing 
for ducted systems be conducted with ducts fitted and at 50 percent of 
the unit's maximum ESP, subject to a tolerance of -0.00/+0.05 in. wc. 
Id. DOE proposed to include this provision for all ducted units (i.e., 
any ducted low-temperature, medium-temperature, or high-temperature 
refrigeration system). Id. DOE also proposed clarifying that if testing 
using either the indoor or outdoor air enthalpy method, which includes 
a measurement of the air volume rate, the airflow measurement apparatus 
fan would be

[[Page 28817]]

adjusted to set the ESP--otherwise, the ESP could be set by 
symmetrically restricting the outlet of the test duct. Id. If the ESP 
is not provided, DOE proposed that it would be set such that the air 
volume rate for the test is equal to two-thirds of the value that is 
measured for zero ESP operation. Id.
---------------------------------------------------------------------------

    \52\ Inches of water column (``in. wc'') is a unit of pressure 
conventionally used for measurement of pressure differentials.
---------------------------------------------------------------------------

    AHRI-Wine stated that wine cellar manufacturers agree with the 
proposed ESP requirements for ducted units; however, they commented 
that the proposed procedure for when ESP is not provided represents an 
unrealistic reduction in airflow. (AHRI-Wine, No. 30 at p. 4) AHRI-Wine 
provided no data or alternative recommendation for a procedure when ESP 
is not provided. DOE has determined that the two-thirds air volume rate 
is an appropriate value to use when no maximum ESP is provided. DOE 
notes that manufacturers can provide maximum ESP to avoid testing using 
the two-thirds air volume rate.
    AHRI-Wine also commented that wine cellar manufacturers seek 
clarification about whether the air surrounding the ducted evaporator 
or ducted condenser must be at the required 90 [deg]F indoor 
temperature. (AHRI-Wine, No. 30 at p. 3) Furthermore, wine cellar 
manufacturers recommended that all wine cellar units, regardless of 
specified condenser location, be tested only at 90 [deg]F to clarify 
the test procedure and reduce test burden. Id. DOE incorporates by 
reference section 7.3.3.3 of ASHRAE 37-2009, which includes provisions 
for testing ducted units and accounting for duct losses; therefore, DOE 
has determined that the ambient temperature surrounding ducts should 
not affect the test results. Consistent with appendix C and the wine 
cellar test procedure waivers, DOE is requiring in appendix C1 that 
dedicated condensing units located outdoors to be tested at three 
temperatures--35 [deg]F, 59 [deg]F, and 95 [deg]F--while dedicated 
condensing units located indoors must be tested at 90 [deg]F.
7. Variable-, Two-, and Multiple-Capacity Systems
a. Dedicated Condensing Units
    In the April 2022 NOPR, DOE proposed test procedures for variable-, 
two-, and multiple-capacity condensing units. The proposals addressed 
numerous aspects of how such systems would be tested, including (a) 
test conditions (saturated suction temperature and suction temperature) 
for part-load operation, (b) compressor operating levels for part-load 
testing, (c) default unit cooler fan wattage to use in AWEF2 
calculations as a function of compressor operating level, and (d) 
calculation of AWEF2 using multiple levels of compressor operation. 87 
FR 23920, 23962-23967.
(1) Need for Test Procedures for Variable-, Two- and Multiple-Capacity 
Condensing Units
    In response to the DOE's proposal, some comments addressed the need 
for test procedures for multi-/variable-capacity condensing units and 
the potential utility and cost-effectiveness of such systems. 
Specifically, AHRI and KeepRite commented that the market for such 
systems is very small, and that the small market size is not driven by 
lack of test method. AHRI and KeepRite further stated that variable-
capacity system purchases are driven by temperature operating tolerance 
requirements rather than energy savings and suggested that energy cost 
savings would not offset upfront purchase and installation costs. 
(AHRI, No. 30 at p. 8; KeepRite, No. 36 at p. 3) National Refrigeration 
commented that there is no need for multi-/variable-capacity test 
procedures at this time, indicating also that there is limited to no 
evidence that variable-capacity units are more efficient. (National 
Refrigeration, No. 39 at p. 2) In response, DOE notes that the DOE test 
procedures already include test methods for variable-, two-, and multi-
capacity matched-pair refrigeration systems through incorporation by 
reference of AHRI 1250-2009. With the proposal and this final rule, DOE 
is extending this test method to dedicated condensing units tested 
alone, which was included in the ASRAC Term Sheet. (Docket EERE-2015-
BT-STD-0016, No. 56 at p. 3, recommendation #6)
    Despite questions about the need for test procedures for variable-, 
two-, and multi-capacity condensing units, AHRI and KeepRite did 
indicate that the proposal was reasonable. (AHRI, No. 30 at p. 8; 
KeepRite, No. 36 at p. 4) Other commenters' overall comments were 
generally supportive regarding DOE's proposed test methods. (RSG, No. 
41 at p. 2; CA IOUs, No. 42 at p. 1; Efficiency Advocates, No. 37 at p. 
2)
(2) Unit Cooler Fan
    DOE requested comment on its assumptions regarding the unit cooler 
with which a two-, multi-, or variable-capacity condensing unit rated 
alone would be paired in the field, including whether the unit cooler 
fan(s) would have a full speed and a half-speed, the compressor 
operating level at which the unit cooler fan(s) would switch to half-
speed, and the half-speed wattage of the fan(s). 87 FR 23920, 23966.
    AHRI and KeepRite commented that a calculation method should be 
allowed for unit cooler fan power rather than just high or low speed, 
indicating that some variable compressor systems would reduce capacity 
only to 75 percent of full capacity and would not realize a gain from 
unit cooler fan power. (AHRI, No. 30 at pp. 8-9; KeepRite, No. 36 at p. 
4) DOE understands this comment to mean that there would be limited 
efficiency gain for a variable-speed compressor whose lowest capacity 
is no lower than 75 percent of full capacity, and that it would be 
important to consider optimization of unit cooler fan speed. National 
Refrigeration commented that requiring a variable-speed or two-speed 
unit cooler fan would be ideal, but the effectiveness is unknown and 
more research is necessary to determine how to handle it. (National 
Refrigeration, No. 24 at p. 2) Lennox commented that unit coolers with 
which two-, multi-, and variable-capacity dedicated condensing units 
are paired may use technology in addition to two-speed fans, such as 
electronic expansion valves (``EEVs''), dampers, or other electronic 
control valves. (Lennox, No. 35 at p. 6)
    In response, DOE notes that if a manufacturer decides to optimize 
unit cooler fan operation or other design details for a given 
condensing unit's compressor technology, the manufacturer has the 
option of certifying the two components together as a matched pair--
this is already an established part of the test procedure for outdoor 
matched pairs, and DOE is extending the approach to indoor matched 
pairs in this document (see section III.G.7.b of this document).
    DOE notes that the test method under consideration applies to 
dedicated condensing units tested alone--these units would be paired 
with a unit cooler in the field, so it is not clear what technology the 
paired unit cooler might have. For this reason, DOE developed the 
proposal for two-, multi-, and variable-capacity dedicated condensing 
units based on the assumption of limited unit cooler technology 
options. DOE's analysis suggests that use of part-load compressor 
operation has limited to no efficiency benefit when the unit cooler 
fan(s) run at full speed. However, DOE is aware that many unit coolers 
are now sold with two-speed fan motors to meet the current energy 
conservation standards. (No. 44 at p. 2) Hence, DOE determined that it 
is reasonable to assume that field matches of dedicated condensing 
units tested alone would involve, at minimum, a unit cooler with

[[Page 28818]]

a two-speed fan. DOE does not have information that would suggest that 
unit coolers sold alone would typically have fully variable-speed fans, 
EEVs, dampers, or other electronic control valves. For this reason, DOE 
does not believe it is appropriate to establish a test procedure for 
dedicated condensing units tested alone, assuming such technology is 
available in a field-paired unit cooler, therefore DOE has not modified 
the test procedure to reflect the potential benefits of these 
technologies.
    Some commenters indicated that, although unit cooler fans may have 
two speeds, the low speed may be triggered by the off-cycle rather than 
by on-cycle compressor operation. (AHRI, No. 30 at p. 8; Lennox, No. 35 
at p. 6; National Refrigeration, No. 39 at p. 2) As mentioned, DOE 
concluded that running unit cooler fans at full speed during part-load 
operation significantly limits the part-load efficiency benefits. Given 
the prevalence of unit coolers being sold with two-speed fans, DOE 
concludes it is reasonable to assume that such unit coolers would be 
controlled to allow two-speed fan operation during part-load when 
field-matched with a two-, multi-, or variable-speed dedicated 
condensing unit.
    DOE requested comment on its assumptions regarding the compressor 
operating level at which the unit cooler fan(s) would switch from full- 
to half-speed operation. 87 FR 23920, 23966. AHRI commented that no 
change was needed, and National Refrigeration was supportive. (AHRI, 
No. 30 at p. 9; National Refrigeration, No. 39 at p. 2) No commenters 
suggested that switching to half-speed operation should occur at 
different compressor operating levels. Hence, DOE is finalizing the 
test procedure using the same 65 percent compressor operating level 
below which the unit cooler fan(s) would be assumed to operate at half-
speed.
    DOE requested comment on the proposal that the unit cooler fan 
half-speed power input would be 20 percent of full speed power. 87 FR 
23920, 23966. Several commenters agreed with this approach. (AHRI, No. 
30 at p. 9; National Refrigeration, No. 39 at p. 2; Lennox, No. 35 at 
p. 6) DOE is finalizing its test procedure using the 20 percent half-
speed power level.
(3) Part-Load Test Conditions
    DOE requested comment on the compressor part-load operating levels 
for multi- and variable-speed dedicated condensing units tested alone. 
87 FR 23920, 23966. Lennox, AHRI, and National Refrigeration supported 
the proposed levels. (Lennox, No. 35 at p. 6; AHRI, No. 30 at p. 9, 
National Refrigeration, No. 39 at p. 2) DOE is finalizing the test 
procedure using the compressor part-load operating levels proposed in 
the April 2022 NOPR.
    Regarding the test conditions proposed for part-load operation of 
variable-, two-, or multiple-capacity dedicated condensing units, 
several commenters suggested that the differing refrigerant conditions 
specified for the different tests were excessively complex and should 
be simplified. (AHRI, No. 30 at p. 9; Lennox, No. 35 at p. 6; National 
Refrigeration, No. 39 at p. 2) In response to DOE's specific question 
about whether a tabular method for specifying test operating conditions 
or a correlation-based approach should be used, Lennox expressed a 
clear preference for a tabular approach, indicating that the 
correlation approach may provide more flexibility but would require 
more data collection and should be evaluated for accuracy. (Lennox, No. 
35 at p. 6) Other commenters did not express a clear position. For 
example, AHRI commented that, while the correlation approach may 
provide more flexibility, it should be used only if it is shown to be 
more accurate. (AHRI, No. 30 at p. 9)
    DOE's intent in allowing different suction conditions for testing 
was to make the test method more representative of actual operation, in 
which unit cooler effectiveness would improve at part load, suction 
line pressure drop would decrease, and suction line heat transfer would 
be more effective. These factors would combine generally to raise the 
dedicated condensing unit inlet pressure (specified as saturated 
suction temperature in the test procedures) and also the suction 
temperature. 87 FR 23920, 23964.
    Some commenters indicated that these variations would make little 
impact in test results. (Lennox, No. 35 at p. 6) DOE analyzed the 
proposed test conditions to evaluate this statement for outdoor 
refrigeration systems using R-448A, calculating the impact on 
compressor EER \53\ and isolating the impact of the change in suction 
conditions as compared with the full-load test conditions,\54\ and not 
including the potential benefits of improved condenser effectiveness at 
part load nor the potential change in the compressor's compression 
efficiency for different operating conditions. The analysis showed 
that, for medium-temperature dedicated condensing units, the impact of 
the modified suction conditions ranged from -2.3 percent (a decrease) 
to 7.7 percent, with an average of 2.8 percent. For low-temperature 
condensing units, the range of impact was from -3.0 percent to 2.4 
percent, with an average of -0.2 percent. This analysis shows that an 
increase in saturated suction temperature improves compressor EER, 
while an increase in suction temperature reduces compressor EER. These 
factors appear to balance out on average for low-temperature systems, 
while for medium-temperature systems, the improvement associated with 
the saturated suction temperature increase makes more impact than the 
suction temperature increase. In addition, the results do not change 
significantly when considering other refrigerants commonly used in WICF 
refrigeration systems, e.g. R-404A and R-407A. For indoor medium-
temperature refrigeration systems, the overall impact of the changes is 
less pronounced, since testing only with the A conditions using 90 
[deg]F condenser ambient air increases the impact of the refrigerant 
temperature rise in the suction line. For outdoor medium-temperature 
systems, DOE found that raising the saturated suction temperature 1 
[deg]F for all part-load conditions to 24 [deg]F and leaving the 
suction temperature unchanged at 41 [deg]F provided the best overall 
agreement in compressor EER compared with the average EER impact of the 
different proposed test conditions. Consequently, DOE is finalizing the 
specification of suction conditions for testing variable-, two-, and 
multiple-capacity dedicated condensing units with the following 
simplifications: For low-temperature and indoor medium-temperature 
dedicated condensing units, the required part-load test conditions will 
match the full-capacity conditions. For outdoor medium-temperature 
dedicated condensing units, the part-load saturated suction temperature 
will be raised 1 [deg]F to 24 [deg]F, without changing the 41 [deg]F 
suction temperature requirement. DOE believes this approach provides 
the best balance between test procedure simplicity and providing some 
adjustment of operating conditions to represent the impacts of changes 
in unit cooler and suction line response to part load.
---------------------------------------------------------------------------

    \53\ Evaporator capacity divided by compressor input power.
    \54\ 23 [deg]F saturated suction temperature and 41 [deg]F 
temperature for medium-temperature systems; -22 [deg]F saturated 
suction temperature and 5 [deg]F temperature for low-temperature 
systems.
---------------------------------------------------------------------------

b. Indoor Matched Pair and Single-Packaged Units
    DOE proposed in the April 2022 NOPR to establish test procedures 
for indoor matched-pair and single-

[[Page 28819]]

packaged dedicated systems. 87 FR 23920, 23966.
    National Refrigeration stated that indoor matched pairs have less 
potential for part-load energy savings than their outdoor counterparts 
due to their constant condensing inlet temperature. (National 
Refrigeration, No. 39 at p. 2) KeepRite stated that the proposed 
approach for indoor matched pairs is acceptable, even though these 
units have even less potential for part-load energy savings due to the 
constant condenser inlet temperature. (KeepRite, No. 36 at p. 4) DOE 
understands that these commenters were referring to constant condenser 
air inlet temperature, which would result in constant condensing 
temperature. Lennox supported the proposal to establish test methods 
for indoor two-, multi-, or variable-capacity condensing units tested 
alone. (Lennox, No. 35 at p.6) No commenters indicated that DOE should 
not establish test methods for such systems. Hence, DOE is adopting the 
test method as proposed.
c. Revision to EER Calculation for Outdoor Variable-Capacity and 
Multiple-Capacity Refrigeration Systems
    In the April 2022 NOPR, DOE proposed to revise the EER calculations 
for outdoor variable-capacity and multiple-capacity refrigeration 
systems to use a piecewise linear calculation approach rather than the 
parabolic equation provided in AHRI 1250-2020. 87 FR 23920, 23966. DOE 
did not receive any comments specifically addressing this proposal and 
is finalizing the test procedure with the revisions as proposed.
d. Digital Compressors
    In the April 2022 NOPR, DOE discussed specific proposals associated 
with digital compressors. To clarify the test procedure for digital 
compressors, DOE proposed to define ``digital compressor'' as a 
compressor that uses mechanical means for disengaging active 
compression on a cyclic basis to provide a reduced average refrigerant 
flow rate in response to an input signal. 87 FR 23920, 23967. DOE 
received no comments specifically addressing the digital compressor 
definition and will adopt the definition as proposed.
    As discussed in the April 2022 NOPR, DOE had conducted testing and 
found that the refrigerant enthalpy method for measuring capacity is 
accurate if the liquid subcooling at the mass flow meter is 
sufficiently low, as required in section C3.4.5 of AHRI 1250-2020. Id. 
DOE proposed that testing refrigeration equipment with digital 
compressors operating at part load may use the refrigerant enthalpy 
method as a secondary test method, with the following provisions and 
adjustments: (1) pressure and temperature measurement would be at a 
frequency of once per second or faster, (2) the operating tolerances 
for pressure and temperature at both the inlet and outlet connections 
and for mass flow would not apply, and (3) enthalpies determined for 
the capacity calculation would be based on test-period-average pressure 
and temperature values. Id.
    DOE also proposed that the selection of the primary test method for 
measuring capacity would depend on the refrigeration system 
configuration. Id. For single-packaged dedicated systems, the test 
methods adopted as primary methods for any single-packaged dedicated 
system would be used, as discussed in section III.G.2 of this document. 
Matched pairs would use the same primary methods used for single-
packaged dedicated systems. For dedicated condensing units, the primary 
methods include outdoor air enthalpy method, balanced ambient outdoor 
calorimeter, and outdoor room calorimeter measurements.
    Lennox supported the proposals for the part-load test procedure for 
refrigeration systems with digital compressors. (AHRI, No. 30 at p. 10; 
Lennox, No. 35 at p. 7) KeepRite and AHRI commented that the 
refrigerant enthalpy method may be unreliable for digital compressors 
because they cannot achieve steady state. However, these commenters did 
not provide evidence that the method would be unreliable. (KeepRite, 
No. 36 at p. 4; AHRI, No. 30 at p. 9) KeepRite and AHRI also indicated 
that 1-second intervals for power measurements would not be sufficient 
for energy measurement of digital compressors and that integrating 
power meters must be used. Id. However, AHRI also stated that the part-
load test procedure for refrigeration systems with digital compressors 
is sufficient as written. (AHRI, No. 30 at p. 9) AHRI provided further 
specific comments, including (a) wider refrigerant pressure and mass 
flow tolerances look acceptable, (b) the 1-second or higher data 
acquisition rate looks acceptable, but that industry-wide ability to 
sample at this rate should be assessed, (c) that when using the 
refrigerant enthalpy method with single-package systems with digital 
compressors, the existing primary methods look acceptable, and (d)-(e) 
when using the refrigerant enthalpy method to test matched pairs or 
condensing units alone with digital compressors, the existing dual 
instrumentation method should be an acceptable primary method for 
measuring capacity. (AHRI, No. 30 at pp. 9, 10)
    DOE notes that the industry standard, AHRI 1250-2020, already has a 
requirement that energy measurements be made using an integrating watt-
hour meter and that power measurements be made with a sampling rate of 
no less than 1 per second (see section C10.2.1.4 of AHRI 1250-2020)--
thus, through incorporation by reference of AHRI 1250-2020, the 
proposal is already consistent with the KeepRite and AHRI comments 
regarding use of an integrating power meter for energy measurements and 
already adopts 1-second intervals for data acquisition. It is DOE's 
understanding that test laboratories already use data acquisition 
systems with this level of capability. As indicated, the commenters did 
not provide data countering the cited DOE evidence that the refrigerant 
enthalpy method measurement is accurate. Given the limited data 
available on this issue, DOE is not deviating from its proposal that 
the refrigerant enthalpy method only be used as a secondary capacity 
measurement, i.e., the test procedure as finalized in this document 
does not allow it to be used as a primary capacity measurement as 
recommended by AHRI for matched pairs and dedicated condensing units 
tested alone. Therefore, DOE is adopting the proposals for digital 
compressor systems as stated in the April 2022 NOPR.
8. Defrost
    The current test procedure references section C11 of AHRI 1250-2009 
to measure defrost. In section C11 of AHRI 1250-2009, the moisture to 
provide a frost load is introduced through the infiltration of air at a 
75.2 [deg]F dry-bulb temperature and a 64.4 [deg]F wet-bulb temperature 
into the walk-in freezer at a constant airflow rate that depends on the 
refrigeration capacity of the tested freezer unit (Equations C11 and 
C12 in section C11.1.1 of AHRI 1250-2009). A key issue with this 
approach is the difficulty in ensuring repeatable frost development on 
the unit under test, despite specifying the infiltration air dry-bulb 
and wet-bulb temperatures. For example, in addition to frost 
accumulating on the evaporator of the unit under test, frost may also 
accumulate on the evaporator of other cooling equipment used to 
condition the room, which could subsequently affect the rate of frost 
accumulation on the unit under test by affecting the amount of moisture 
remaining in the air.
    Since there are recognized limitations to the defrost test 
procedure in section C11 of AHRI 1250-2009, AHRI 1250-

[[Page 28820]]

2020 does not include a frosted-coil test but does include provisions 
for a dry-coil defrost test.\55\ Industry is currently evaluating how 
to create and validate consistent evaporator coil frost loads; 
therefore, in the April 2022 NOPR, DOE proposed to maintain the current 
calculation-based approach for estimating defrost energy consumption. 
Specifically, DOE proposed to incorporate by reference section C10 of 
AHRI 1250-2020 for unit coolers with either electric or hot gas 
defrost, except for section C10.2.1.1, ``Test Room Conditioning 
Equipment.'' At this time, DOE does not have sufficient data to fully 
evaluate how the test room condition requirements in section C10.2.1.1 
of AHRI 1250-2020 would impact the representativeness of the test 
procedure during the dry-coil defrost test relative to potential 
additional test burden.
---------------------------------------------------------------------------

    \55\ AHRI 1250-2020 includes an adaptive defrost challenge test 
in appendix E (Appendix E) and a hot gas defrost challenge test in 
appendix F (Appendix F) that require a frosted-coil. The tests in 
both of these appendices are labeled as ``informative,'' and were 
designed to evaluate adaptive defrost or hot gas defrost 
functionality, respectively, rather than to quantify defrost energy 
use.
---------------------------------------------------------------------------

    In response to the April 2022 NOPR, HTPG commented that it agreed 
with the proposal to incorporate the entirety of Section C10 of AHRI 
1250-2020, except for section C10.2.1.1. (HTPG, No. 32 at p. 7) HTPG 
also agreed that all systems would use the same default calculated 
values to rate defrost power. Id.
    The CA IOUs stated that they support DOE adopting a test method for 
measuring defrost energy use in a future test procedure and that if DOE 
adopts a test method, DOE should reconsider the frequency at which 
defrost is used. (CA IOUs, No. 42 at p. 2) DOE will continue to 
evaluate defrost energy use and may address defrost energy in a future 
test procedure rulemaking. In this final rule, DOE is adopting the 
procedures as proposed in the April 2022 NOPR in appendix C1.
a. Adaptive Defrost
    Adaptive defrost refers to a factory-installed defrost control 
system that reduces defrost frequency by initiating defrosts or 
adjusting the number of defrosts per day in response to operating 
conditions, rather than initiating defrost strictly based on compressor 
run time or clock time. 10 CFR 431.303. In the April 2022 NOPR, DOE 
proposed to maintain its current requirements for adaptive defrost. 87 
FR 23920, 23969. DOE received no comments on its proposal. In this 
final rule, DOE is maintaining the current regulatory approach to 
include the optional representation strategy for adaptive defrost.
b. Hot Gas Defrost
    In the April 2022 NOPR, DOE proposed that manufacturers may account 
for a unit's potential improved performance with hot gas defrost in its 
market representations. 87 FR 23920, 23970. DOE proposed that this hot 
gas defrost ``credit'' may be used in marketing materials for all 
refrigeration system varieties sold with hot gas defrost (i.e., matched 
pairs, standalone unit coolers, and standalone condensing units). Id.
    However, due to the variation of hot gas defrost applications 
across the refrigeration systems market, and a lack of consensus on the 
definition of ``hot gas defrost'' systems (see discussion in section 
III.A.2.i of this document), DOE is not adopting a hot gas defrost 
``credit'' for representation purposes.
9. Refrigerant Glide
    Refrigerant glide refers to the increase in temperature at a fixed 
pressure as liquid refrigerant vaporizes during its conversion from 
saturated liquid (at its bubble point) to saturated vapor (at its dew 
point). R-404A--a common walk-in refrigerant--has very little glide, 
while R-407A--another common walk-in refrigerant--can exhibit glide of 
up to 8 [deg]F.
    The current DOE test procedure specifies unit cooler test 
conditions based on the dew point at the evaporator exit. For zero-
glide refrigerants, the average evaporator temperature will typically 
be equivalent to the specified dew point. However, for high-glide 
refrigerants, the average evaporator temperature will be significantly 
lower than the dew point since the refrigerant temperature will 
increase (up to the dew point) as it travels through the evaporator. As 
a result, two identical unit coolers, one charged with R-404A and one 
with R-407A, will be tested at different evaporator-to-air temperature 
differences (``TD''), but with the same evaporator airflow. Measured 
capacity is directly correlated with the product of TD and airflow; 
therefore, the high-glide R-407A unit cooler would achieve a higher 
rated capacity than the R-404A unit cooler. However, this capacity 
difference is an artifact of the test procedure, which requires that 
unit coolers and dedicated condensing units be tested alone. In the 
field, a unit cooler will be paired with a dedicated condensing unit, 
and R-407A unit coolers will not actually provide additional capacity 
when compared to their R-404A counterparts. For these reasons, the 
current test procedure is not refrigerant-neutral.
    In the April 2022 NOPR, DOE discussed how the current test 
procedure is not refrigerant-neutral in terms of high-glide and zero-
glide refrigerants because it uses dewpoint throughout the test 
procedure. 87 FR 23920, 23970. DOE also discussed the modified midpoint 
approach, which is more refrigerant-neutral. The modified midpoint 
approach attempts to standardize the average evaporator temperature, 
rather than standardizing the evaporator dew point. In doing so, 
identical unit coolers using zero- and high-glide refrigerants would 
exhibit identical TDs, thus alleviating concerns of overstated 
capacity.
    While a modified midpoint approach may be more refrigerant-neutral, 
DOE notes that the AHRI 1250-2020, which DOE is referencing in appendix 
C1, uses a dewpoint rather than a modified midpoint approach. DOE does 
not have enough information at this time to justify the use of a 
modified midpoint approach. As a result, in the April 2022 NOPR, DOE 
proposed to continue to use dew point throughout the test procedure. 
Id.
    In response to the April 2022 NOPR, HTPG commented that it 
disagrees with the midpoint approach and suggested maintaining the dew 
point approach. (HTPG, No. 32 at p. 7) DOE is adopting the proposal 
from the April 2022 NOPR and continuing to specify refrigerant 
conditions using dew point.
10. Refrigerant Temperature and Pressure Instrumentation Locations
    As discussed in the April 2022 NOPR, the specified superheat in 
AHRI 1250-2020 differs from the current DOE test procedure for 
dedicated condensing unit efficiency calculations, but there is no 
effective difference in where the required pressure and temperature 
measurements should be taken on the equipment under test. 87 FR 23920, 
23971. However, Figure C2 in AHRI 1250-2020 suggests that the use of a 
suction line mass flow meter for these measurements is not allowed. In 
the April 2022 NOPR, DOE proposed to clarify that a second mass flow 
meter in the suction line would be allowed with the adoption of AHRI 
1250-2020. Id. Specifically, DOE clarified that the second mass flow 
measurement for the DX dual instrumentation method may be in the 
suction line upstream of the inlet to the condensing unit, as shown in 
Figure C1 of AHRI 1250-2009. AHRI, HTPG, Lennox, Hussmann, and RSG 
agreed with the proposal. (AHRI, No. 30 at p. 10; HTPG, No. 32 at p. 7; 
Lennox,

[[Page 28821]]

No. 35 at p. 7; Hussmann, No. 38 at p. 10; RSG, No. 41 at p. 2)
    AHRI also commented that DOE should only reference AHRI 1250-2020, 
not both AHRI 1250-2020 and AHRI 1250-2009, for the location of flow 
meters. (AHRI, No. 30 at p. 10) DOE is clarifying that only AHRI 1250-
2020 will be referenced in appendix C1, and that AHRI 1250-2009 is 
mentioned in this discussion only to explain the intention of the 
proposal. Therefore, DOE is adopting the test procedure as proposed in 
the April 2022 NOPR.
11. Updates to Default Values for Unit Cooler Parameters
    As discussed in section III.B.3.c, Sections 7.9.1 and 7.9.2 of AHRI 
1250-2020 add new equations to calculate on-cycle evaporator fan power 
when testing a dedicated condensing unit alone. These equations are 
different from those in the current test procedure in appendix C, which 
calculates on-cycle evaporator fan power based on the cooling capacity 
of the condensing unit. The equations in AHRI 1250-2020 are based on 
more test data and analysis than those currently in appendix C. In the 
April 2022 NOPR, DOE proposed to adopt the calculations for on-cycle 
evaporator fan power for dedicated condensing units tested alone as 
prescribed in AHRI 1250-2020. 87 FR 23920, 23971-23972.
    AHRI, HTPG, Lennox, and RSG agreed with the proposed on-cycle 
evaporator fan power calculations. (AHRI, No. 30 at p. 10; HTPG, No. 32 
at p. 7; Lennox, No. 35 at p. 7; RSG, No. 41 at p. 2) DOE is adopting 
the test procedure as proposed in the April 2020 NOPR.
12. Calculations and Rounding
    In the April 2022 NOPR, DOE proposed new rounding requirements for 
AWEF and capacity to ensure greater test procedure consistency. 87 FR 
23920, 23972. DOE clarifies here that the rounding requirements 
proposed in the April 2022 NOPR should have been for AWEF2 and not 
AWEF, which means that any rounding requirements would become effective 
when appendix C1 becomes effective.
    DOE recognizes that the way values are rounded can affect the 
resulting capacity and AWEF2 values. To ensure consistency in 
calculating capacity and AWEF2 values, DOE proposed in the April 2022 
NOPR that raw measured data be used in all capacity and AWEF2 
calculations. Id. DOE's current standards specify a minimum AWEF2 value 
in Btu/(W-h) to the hundredths place. DOE proposed rounding AWEF2 
values to the nearest 0.05 Btu/(W-h). Id. To round capacity, DOE 
proposed to round to the nearest multiple as specified in Table III.7. 
The proposed capacity bins and multiples are consistent with other HVAC 
test procedures.\56\
---------------------------------------------------------------------------

    \56\ A version of Table III.14 can be found in AHRI Standard 390 
I-P (2021), ``Performance Rating of Single-Package Vertical Air-
conditioners and Heat Pumps.''

  Table III.7--Refrigeration Capacity Rating Ranges and Their Rounding
                                Multiples
------------------------------------------------------------------------
                                                          Multiples, Btu/
       Refrigeration capacity ratings, 1,000 Btu/h               h
------------------------------------------------------------------------
<20.....................................................             100
>=20 and <38............................................             200
>=38 and <65............................................             500
>=65....................................................           1,000
------------------------------------------------------------------------

    AHRI, HTPG, KeepRite, Lennox, and National Refrigeration 
recommended that AWEF2 values be rounded to the nearest 0.01 Btu/(W-h), 
as current standards are taken to that precision. (AHRI, No. 30 at pp. 
10-11; HTPG, No. 32 at p. 8; KeepRite, No. 36 at p. 4; Lennox, No. 35 
at p. 7; National Refrigeration, No. 39 at p. 2) DOE agrees that 
rounding to the nearest 0.05 Btu/(W-h) as proposed may cause confusion. 
Therefore, DOE is requiring that AWEF2 values be rounded to the nearest 
0.01 Btu/(W-h).
    AHRI, AHRI-Wine, and RSG agreed with the proposed capacity ranges 
and respective rounding requirements. (AHRI, No. 30 at p. 10; AHRI-
Wine, No. 30 at p. 4; RSG, No. 41 at p. 2) DOE is adopting the capacity 
rounding requirements as proposed in the April 2022 NOPR and summarized 
in Table III.7.

H. Alternative Efficiency Determination Methods for Refrigeration 
Systems

    Pursuant to the requirements of 10 CFR 429.70, DOE may permit use 
of an AEDM in lieu of testing equipment for which testing burden may be 
considerable and for which that equipment's energy efficiency 
performance may be well predicted by such alternative methods. Although 
specific requirements vary by product or equipment, use of an AEDM 
entails development of a mathematical model that estimates energy 
efficiency or energy consumption characteristics of the basic model, as 
would be measured by the applicable DOE test procedure. The AEDM must 
be based on engineering or statistical analysis, computer simulation or 
modeling, or other analytic evaluation of performance data. A 
manufacturer must perform validation of an AEDM by demonstrating that 
the performance, as predicted by the AEDM, agrees with the performance 
as measured by actual testing in accordance with the applicable DOE 
test procedure. The validation procedure and requirements, including 
the statistical tolerance, number of basic models, and number of units 
tested vary by product or equipment.
    Once developed, an AEDM may be used to rate and certify the 
performance of untested basic models in lieu of physical testing. 
However, use of an AEDM for any basic model is always at the option of 
the manufacturer. One potential advantage of AEDM use is that it may 
free a manufacturer from the burden of physical testing. One potential 
risk is that the AEDM may not perfectly predict performance, and the 
manufacturer could be found responsible for having an invalid rating 
for the equipment in question or for having distributed a noncompliant 
basic model. The manufacturer, by using an AEDM, bears the 
responsibility and risk of the validity of the ratings. For walk-ins, 
DOE currently permits the use of AEDMs for refrigeration systems only. 
10 CFR 429.70(f).
    In a final rule published on May 13, 2014, DOE established that 
AEDMs can be used by walk-in refrigeration manufacturers, once certain 
qualifications are met, to certify compliance and report ratings. 79 FR 
27388, 27389. That rule established a uniform, systematic, and fair 
approach to the use of these types of modeling techniques that has 
enabled DOE to ensure that products in the marketplace are correctly 
rated--irrespective of whether they are subject to actual physical 
testing or are rated using modeling--without unnecessarily burdening 
regulated entities. Id. A minimum of two distinct models must be tested 
to validate an AEDM for each validation class.
    DOE is adopting new test procedures for single-packaged dedicated 
systems, high-temperature refrigeration systems, and CO2 
unit coolers. Application design temperature of the refrigerated 
environment has a significant impact on equipment performance; 
therefore, in the April 2022 NOPR, DOE proposed to incorporate new AEDM 
validation classes for all high-temperature refrigeration systems 
(single-packaged dedicated systems and matched-pair systems). 87 FR 
23920, 23973. Additionally, single-packaged units are expected to 
perform differently than dedicated condensing units under the test 
procedure which incorporates thermal losses. Therefore, in the April

[[Page 28822]]

2022 NOPR, DOE proposed to create new validation classes for low-
temperature, medium-temperature, and high-temperature single-packaged 
dedicated systems. Id. To ensure that walk-in validation classes are 
consistent with DOE's current walk-in terminology, DOE proposed to 
rename the ``unit cooler connected to a multiplex condensing unit'' 
validation classes to ``unit cooler'' at either medium- or low-
temperature; however, the AEDM requirements for these classes remain 
the same. Id. Finally, DOE proposed to remove the medium-/low-
temperature indoor/outdoor condensing unit validation classes, as these 
are redundant with the medium-/low-temperature indoor/outdoor dedicated 
condensing unit validation classes. Id.
    Implementation of appendix C1 will require that all AEDMs for 
single-packaged dedicated systems are amended to be consistent with the 
test procedure proposed in appendix C1.
    The AEDM validation classes for walk-in refrigeration equipment DOE 
proposed in the April 2022 NOPR are as follows:

 Dedicated Condensing Unit, Medium-Temperature, Indoor System
 Dedicated Condensing Unit, Medium-Temperature, Outdoor System
 Dedicated Condensing Unit, Low-Temperature, Indoor System
 Dedicated Condensing Unit, Low-Temperature, Outdoor System
 Single-packaged Dedicated System, High-Temperature, Indoor 
System
 Single-packaged Dedicated System, High-Temperature, Outdoor 
System
 Single-packaged Dedicated System, Medium-Temperature, Indoor 
System
 Single-packaged Dedicated System, Medium-Temperature, Outdoor 
System
 Single-packaged Dedicated System, Low-Temperature, Indoor 
System
 Single-packaged Dedicated System, Low-Temperature, Outdoor 
System
 Matched Pair, High-Temperature, Indoor Condensing Unit
 Matched Pair, High-Temperature, Outdoor Condensing Unit
 Matched Pair, Medium-Temperature, Indoor Condensing Unit
 Matched Pair, Medium-Temperature, Outdoor Condensing Unit
 Matched Pair, Low-Temperature, Indoor Condensing Unit
 Matched Pair, Low-Temperature, Outdoor Condensing Unit
 Unit Cooler, High-Temperature
 Unit Cooler, Medium-Temperature
 Unit Cooler, Low-Temperature

    Additionally, DOE proposed in the April 2022 NOPR to maintain the 
provision that outdoor models within a given validation class may be 
used to determine represented values for the corresponding indoor 
class, and additional validation testing is not required. 87 FR 23920, 
23973. For example, two medium-temperature outdoor dedicated condensing 
units may be used to validate an AEDM for both the ``Dedicated 
Condensing Unit, Medium-Temperature, Outdoor System'' class and the 
``Dedicated Condensing Units, Medium-Temperature, Indoor System'' 
class. If indoor models that fall within a given validation class are 
tested and used to validate an indoor AEDM, however, that test data may 
not be used to validate the equivalent outdoor validation class.
    In the April 2022 NOPR, DOE proposed no additional modifications to 
the walk-in specific AEDM provisions within 10 CFR 429.70(f). Id. In 
the April 2022 NOPR, DOE requested comment on its proposal to modify 
and extend its AEDM validation classes. Id.
    AHRI, Lennox, National Refrigeration, and RSG agreed with the 
proposed AEDM validation classes. (AHRI, No. 30 at p. 11; Lennox, No. 
35 at p. 8; National Refrigeration, No. 39 at p. 2; RSG, No. 41 at p. 
3) HTPG agreed with DOE's proposals to (1) add single-packaged 
dedicated system validation classes, (2) to rename ``unit cooler 
connected to a multiplex condensing unit'' validation classes to ``unit 
cooler,'' and (3) to remove medium-/low-temperature indoor/outdoor 
condensing unit validation classes to eliminate redundancy. (HTPG, No. 
32 at p. 8) AHRI-Wine agreed with the proposed validation classes. 
(AHRI-Wine, No. 30 at p. 4)
    AHRI-Wine requested clarification on whether there are AEDM 
validation classes for high-temperature dedicated condensing units. Id. 
DOE is clarifying that there are no AEDM validation classes for high-
temperature dedicated condensing units. As discussed in section 
III.F.7, DOE has found that the wine cellar industry seems to use 
general-purpose dedicated condensing units, which must meet the medium-
temperature dedicated condensing unit energy conservation standard and 
should be certified as such. These general-purpose dedicated condensing 
units would fall into the ``Dedicated Condensing Unit, Medium-
Temperature Outdoor System'' or ``Dedicated Condensing Unit, Medium-
Temperature Indoor System'' AEDM validation class.
    DOE is adopting the AEDM validation classes for refrigeration 
systems as proposed in the April 2022 NOPR.

I. Sampling Plan for Enforcement Testing

    As discussed in the April 2022 NOPR, DOE uses appendix B to subpart 
C of 10 CFR part 429 to assess compliance for walk-in refrigeration 
systems, which is specifically intended for use for covered equipment 
and certain low-volume covered products. 87 FR 23920, 23973. DOE does 
not specifically reference which appendix in subpart C of 10 CFR part 
429 it uses for determination of compliance for walk-in doors or walk-
in panels. In an Enforcement NOPR published on August 31, 2020 
(``August 2020 Enforcement NOPR''), DOE proposed to add walk-in cooler 
and freezer doors and walk-in panels to the list of equipment subject 
to the low-volume enforcement sampling procedures in appendix B to 
subpart C of 10 CFR part 429. 85 FR 53691, 53696. DOE noted that this 
equipment is not currently included within DOE's list because when the 
current regulations were drafted, walk-in doors and walk-in panels did 
not have applicable performance standards, only design standards, and 
therefore sampling provisions were not necessary at the time. In the 
April 2022 NOPR, DOE proposed to include walk-in doors and walk-in 
panels in the list of covered equipment and certain low-volume products 
at 10 CFR 429.110(e)(2). 87 FR 23920, 23973.
    AHRI, Hussmann, Bally, and RSG all requested clarification on the 
definition of ``low-volume.'' (AHRI, No. 30 at p. 11; Hussmann, No. 34 
at p. 4; Bally, No. 40 at p. 5; RSG, No. 41 at p. 3)
    DOE does not define a numerical threshold for ``low-volume'' or 
``high-volume'' products and equipment, and for some products and 
equipment the Department may consider volume on a case-by-case basis. 
DOE created the ``low-volume'' designation to separate built-to-order 
equipment from pre-manufactured, off the shelf products, providing 
built-to-order equipment a longer time period to ship a basic model. 76 
FR 12421, 12435. In the context of enforcement, 10 CFR 429.110(e)(1) 
states that DOE will use a sample size of not more than 21 units and 
follow the sampling plans in appendix A to subpart C of 10 CFR part 429 
to determine compliance with the applicable DOE standards for high-
volume equipment, while DOE will use a sample size of not more than 4 
units and follow the sampling plans in appendix B to subpart C of 10 
CFR part 429 to determine compliance with the applicable DOE standards 
for low-volume equipment. As specified in 10 CFR 429.110(b), units 
selected for

[[Page 28823]]

enforcement evaluation are provided by the manufacturer. DOE notes that 
walk-in refrigeration systems are currently included in the list of 
covered equipment and certain low-volume products at 10 CFR 
429.110(e)(2). Including walk-in door and panels ensures all walk-in 
components are similarly evaluated. DOE is including walk-in doors and 
panels in the list of covered equipment and certain low-volume covered 
products at 10 CFR 429.110(e)(2) and thus will use the sampling plan in 
appendix B to subpart C of 10 CFR part 429.
    DOE is adopting the enforcement sampling plan as proposed in the 
April 2022 NOPR.
    Bally also asked for clarification regarding how the low-volume 
sampling procedures work when coupled with new section 5.4.3 of 
appendix B to subpart R of 10 CFR part 431. (Bally, No. 40 at p. 5) 
Bally asked whether appendix B to subpart C of 10 CFR part 429 is a 
restatement of 10 CFR 429.53(a)(3)(ii)(B)(2). Id. DOE notes that the 
sampling plan provisions in appendix B to subpart C of 10 CFR part 429 
are strictly for the Department's evaluation of compliance when 
conducting enforcement testing. The provisions at 10 CFR 
429.53(a)(3)(ii)(B)(2) are the requirements that manufacturers are 
required to follow when determining the represented value certified to 
DOE. DOE did not propose to make changes to the certification language 
in the April 2022 NOPR. The provisions in the new section 5.4.3 of 
appendix B to subpart R of 10 CFR part 431 are intended to allow 
manufacturers to use K-factor test results from a set of test samples 
to determine R-value of envelope components with varying foam 
thicknesses as long as the foam throughout the panel is of the same 
final chemical form and the test was completed at the same test 
conditions as other envelope components. In other words, if a 
manufacturer offers 4-inch and 5-inch cooler panels, the manufacturer 
may use the K-factor results of a single series of tests to determine 
the R-value for both the 4-inch and 5-inch cooler panels.

J. Organizational Changes

    In the April 2020 NOPR, DOE proposed a number of non-substantive 
organizational changes. 87 FR 23920, 23977. As discussed previously, 
DOE proposed to reorganize appendices A and B so that they are easier 
for stakeholders to follow as a step-by-step test procedure. 
Additionally, DOE proposed to remove the specifications at 10 CFR 
429.53(a)(2)(i) regarding specific test procedure provisions and 
instead include these provisions in the uniform test method section at 
10 CFR 431.304. The intent of this proposed change was to move 
provisions of the applicable test procedure to the appropriate place in 
subpart R, rather than keeping them under the provisions for 
determining represented values for certification. However, DOE proposed 
to keep the additional detail regarding the represented values of 
various configurations of refrigeration systems (e.g., outdoor and 
indoor dedicated condensing units, matched refrigeration systems, etc.) 
at 10 CFR 429.53(a)(2)(i).
    DOE received no comment on these proposals regarding organizational 
changes and therefore is adopting them as proposed in the April 2022 
NOPR.

K. Test Procedure Costs and Impact

    EPCA requires that test procedures proposed by DOE be reasonably 
designed to produce test results which reflect energy efficiency and 
energy use of a type of industrial equipment during a representative 
average use cycle and not be unduly burdensome to conduct. (42 U.S.C. 
6314(a)(2)) The following sections discuss DOE's evaluation of the 
estimated costs and savings associated with the amendments in this 
final rule.
1. Doors
    In this document, DOE is adopting the following amendments to the 
test procedures in appendix A for walk-in cooler and freezer doors:
     Referencing NFRC 102-2020 for the determination of U-
factor;
     Including AEDM provisions for manufacturers to alternately 
determine the total energy consumption of display and non-display 
doors;
     Providing additional detail for determining the area used 
to convert U-factor into conduction load, As, to 
differentiate it from the area used to determine compliance with the 
standards, Add or And;
     Specifying a PTO value of 97 percent for door motors.
    The first and third amendments, referencing NFRC 102-2020 and 
additional detail on the area used to convert U-factor into a 
conduction load, improve the consistency, reproducibility, and 
representativeness of test procedure results. The second amendment, 
including AEDM provisions, intends to provide manufacturers with the 
flexibility to use an alternative method to testing that provides good 
agreement for their doors. The fourth amendment, including a PTO value 
of 97 percent, intends to provide a more representative and consistent 
means for comparison of walk-in door performance for doors with motors.
    DOE has determined that these proposed amendments would improve the 
representativeness, accuracy, and reproducibility of the test results, 
and would not be unduly burdensome for door manufacturers to conduct. 
DOE has also determined that these proposed amendments would not 
increase testing costs per basic model relative to the current DOE test 
procedure in appendix A, which DOE estimates to be $10,000 for third-
party labs to determine energy consumption of a walk-in door, including 
physical U-factor testing per NFRC 102-2020.\57\ Finally, DOE has 
determined that manufacturers would not be required to redesign any of 
the covered equipment or change how the equipment is manufactured 
solely as a result of these amendments.
---------------------------------------------------------------------------

    \57\ DOE estimates the cost of one test to determine energy 
consumption of a walk-in door, including one physical U-factor test 
per NFRC 102-2020, to be $5,000. Per the sampling requirements 
specified at 10 CFR 429.53(a)(3)(ii) and 429.11(b), manufacturers 
are required to test at least two units to determine the rating for 
a basic model, except where only one unit of the basic model is 
produced.
---------------------------------------------------------------------------

    The cost impact to manufacturers as a result of the reference to 
NFRC 102-2020 and inclusion of AEDM provisions is dependent on the 
agreement between tested and simulated values as specified in section 
4.7.1 of NFRC 100-2010 \58\ and as referenced in the current test 
procedure. For manufacturers of doors that have been able to achieve 
the specified agreement between U-factors simulated using the method in 
NFRC 100-2010 and U-factors tested using NFRC 102-2020, after 
physically conducting testing to validate the AEDM, manufacturers would 
be able to continue using the simulation method in NFRC 100-2010 
provided it meets the basic requirements proposed for an AEDM in 10 CFR 
429.53 and 429.70(f).
---------------------------------------------------------------------------

    \58\ Section 4.7.1 of NFRC 100-2010 requires that the accepted 
difference between the tested U-factor and the simulated U-factor be 
(a) 0.03 Btu/(h-ft\2\-[deg]F) for simulated U-factors that are 0.3 
Btu/(h-ft\2\-[deg]F) or less, or (b) 10 percent of the simulated U-
factor for simulated U-factors greater than 0.3 Btu/(h-ft\2\-
[deg]F). This agreement must match for the baseline product in a 
product line. Per NFRC 100-2010, the baseline product is the 
individual product selected for validation; it is not synonymous 
with ``basic model'' as defined in 10 CFR 431.302.
---------------------------------------------------------------------------

    For manufacturers of doors that have not been able to achieve the 
specified agreement between U-factors simulated using the method in 
NFRC 100-2010 and U-factors tested using NFRC 102-2020, DOE estimates 
that the test burden would decrease. Under the current requirements, 
manufacturers may be required to determine U-factor through physical 
testing of every basic model. With the new test procedure,

[[Page 28824]]

manufacturers who would have otherwise been required to physically test 
every walk-in door basic model could develop an AEDM for rating their 
basic models of walk-in doors consistent with the proposed provisions 
in 10 CFR 429.53 and 429.70(f). DOE estimates the per-manufacturer cost 
to develop and validate an AEDM for a single validation class of walk-
in doors to be $11,100. DOE estimates an additional cost to determine 
energy consumption of a walk-in door using an AEDM to be $46 per basic 
model.\59\
---------------------------------------------------------------------------

    \59\ DOE estimated initial costs to validate an AEDM assuming 24 
hours of general time to develop and validate an AEDM based on 
existing simulation tools. DOE estimated the cost of an engineering 
calibration technician fully burdened wage of $46 per hour plus the 
cost of third-party physical testing of two basic models per 
proposed validation class. DOE estimated the additional per basic 
model cost to determine efficiency using an AEDM assuming 1 hour per 
basic model at the cost of an engineering calibration technician 
wage of $46 per hour.
---------------------------------------------------------------------------

    DOE expects that the additional detail provided for determining the 
area used to convert U-factor into conduction load, As, 
would either result in reduced energy consumption or have no impact. To 
the extent that this change to the test procedure would amend the 
energy consumption attributable to a door, such changes would either 
not change the calculated energy consumption or result in a lower 
energy consumption value as compared to how manufacturers may currently 
be rating, given that the current test procedure does not provide 
specific details on measurement of Add and And. 
As such, DOE expects that manufacturers would be able to rely on data 
generated under the current test procedure. While manufacturers must 
submit a report annually to certify a basic model's represented values, 
basic models do not need to be retested annually. The initial test 
results used to generate a certified rating for a basic model remain 
valid if the basic model has not been modified from the tested design 
in a way that makes it less efficient or more consumptive, which would 
require a change to the certified rating. If a manufacturer has 
modified a basic model in a way that makes it more efficient or less 
consumptive, new testing is only required if the manufacturer wishes to 
make claims using the new, more efficient rating.\60\
---------------------------------------------------------------------------

    \60\ See guidance issued by DOE at www1.eere.energy.gov/buildings/appliance_standards/pdfs/cert_faq_2012-04-17.pdf.
---------------------------------------------------------------------------

    For doors without motors, DOE has concluded that the proposed test 
procedure would not change energy consumption ratings, which would not 
require rerating solely as result of DOE's adoption of this amendment 
to the test procedure. Therefore, DOE has determined all proposed 
amendments either decrease or result in no additional testing costs to 
manufacturers of walk-in doors.
    To the extent that changes to the test procedure would amend the 
energy consumption attributable to a door motor, such changes would 
either not change the calculated energy consumption or result in a 
lower energy consumption value as compared to the currently granted 
waivers addressing door motors. As such, DOE expects that manufacturers 
would be able to rely on data generated under the current test 
procedure and current waivers. While manufacturers must submit a report 
annually to certify a basic model's represented values, basic models do 
not need to be retested annually. The initial test results used to 
generate a certified rating for a basic model remain valid if the basic 
model has not been modified from the tested design in a way that makes 
it less efficient or more consumptive, which would require a change to 
the certified rating. If a manufacturer has modified a basic model in a 
way that makes it more efficient or less consumptive, new testing is 
only required if the manufacturer wishes to make claims using the new, 
more efficient rating.
    In the April 2022 NOPR, DOE requested comment on its understanding 
of the impact of the test procedure proposals for appendix A. 87 FR 
23920, 23979.
    AHRI stated that it is unable to determine or comment on impact 
until it understands the AEDM for doors. (AHRI, No. 30 at p. 11) DOE 
has provided additional detail regarding AEDMs in section III.C.1 of 
this document and estimates that the test burden would decrease for the 
industry as a whole.
    Bally commented that the $11,000 estimated cost for U-factor 
testing doesn't consider the cost of materials. (Bally, No. 40 at p. 5) 
DOE has determined that the DOE test procedure for walk-in doors is 
non-destructive and that units can therefore be recovered after 
testing. For this reason, DOE does not include the cost of the unit 
under test.
    While stakeholders did not specifically recommend including freight 
costs in the test cost estimates for walk-in doors, they did recommend 
including freight costs in the test cost estimates for walk-in 
refrigeration systems (discussed in section III.K.3 of this document). 
DOE acknowledges that freight costs are an additional expense 
associated with third-party testing. Therefore, to be consistent with 
the estimates provided for refrigeration system testing, DOE has 
estimated the cost of round-trip freight. DOE estimates that the 
shipping cost for a walk-in box from a manufacturing facility to a test 
lab can range from $800 to $2,500 depending on the relative locations 
of the two facilities, the weight and size of the unit being shipped, 
and the discounts associated with shipping multiple units at one time. 
Thus, DOE estimates the round-trip freight costs as ranging from $1,600 
to $5,000.
2. Panels
    In this final rule, DOE is amending the existing test procedure in 
appendix B for measuring the R-value of insulation of panels by:
     Incorporating by reference the updated version of the 
applicable industry test method, ASTM C518-17;
     Including provisions specific to measurement of test 
specimen and total insulation thickness; and
     Providing a method for determining the parallelism and 
flatness of the test specimen.
    The first amendment incorporates by reference the most up-to-date 
version of the industry standards currently referenced in the DOE test 
procedure. The second and third amendments include additional 
instructions intended to improve consistency and reproducibility of 
test procedure results.
    DOE has determined that these proposed amendments would improve the 
accuracy and reproducibility of the test results and would not be 
unduly burdensome for manufacturers to conduct, nor would they be 
expected to increase the testing burden.
    DOE expects that the proposed test procedure in appendix B for 
measuring the R-value of insulation would not increase testing costs 
per basic model relative to the current DOE test procedure, which DOE 
estimates to be $1,200 for third-party laboratory testing.\61\ 
Additionally, DOE has determined that the test procedure in appendix B 
would not result in manufacturers having to redesign any of the covered 
equipment or change how the equipment is manufactured.
---------------------------------------------------------------------------

    \61\ DOE estimates the cost of one test to determine R-value to 
be $600. Per the sampling requirements specified at 10 CFR 
429.53(a)(3)(ii) and 429.11(b), manufacturers are required to test 
at least two units to determine the rating for a basic model, except 
where only one unit of the basic model is produced.
---------------------------------------------------------------------------

    In the April 2022 NOPR, DOE requested comment on its understanding 
of the impact of the test procedure proposals for appendix B. 87 FR 
23920, 23975.
    AHRI agreed with DOE's understanding of the impact of the test

[[Page 28825]]

procedure. (AHRI, No. 30 at p. 12) Bally commented that the increased 
measurement and complex calculations involving least squares regression 
for parallelism and flatness are overly burdensome and that it 
anticipates difficulty finding laboratories capable of doing the 
calculations. (Bally, No. 40 at p. 6) In response to Bally's comment, 
DOE reiterates that the measurement and calculations for parallelism 
and flatness are necessary to improve the accuracy and reproducibility 
of the test results. Additionally, what Bally has identified as 
increased measurement are generally measurements that are already being 
taken by third party laboratories, but which have not been specified in 
the DOE test procedure. With respect to the complexity of the 
calculations, DOE notes that third party laboratories typically use 
templates to run calculations which would be repeated for multiple 
tests conducted and that, while a laboratory may need to initially 
update the template they use, the calculations would not be overly 
complex and burdensome on an ongoing basis for testing. DOE was also 
able to find laboratories capable of doing the additional measurements 
and calculations. Thus, DOE has determined that the procedure is not 
overly burdensome.
    Because the test procedure for walk-in panels is destructive and 
that units cannot be recovered after testing, DOE is including in its 
evaluation the cost of the unit under test. DOE estimates the cost of a 
walk-in panel to range from $90 to $300, depending on size and 
materials used, and when testing a minimum of two units of a basic 
model as required by 10 CFR 429.53(a)(1), a total cost of $180 to $600 
per basic model.
    DOE acknowledges that freight costs are an additional expense 
associated with third-party testing. Therefore, DOE has estimated the 
cost of freight to the test facility. DOE estimates that the shipping 
cost for one walk-in box from a manufacturing facility to a test 
laboratory can range from $800 to $2,500 depending on the relative 
locations of the two facilities, the weight and size of the unit being 
shipped, and the discounts associated with shipping multiple units at 
one time.
3. Refrigeration Systems
    DOE is adopting certain changes to appendix C that DOE has 
determined will improve the accuracy and reproducibility of the test 
results and would not be unduly burdensome for manufacturers to 
conduct. DOE has further determined that these changes will not impact 
testing cost. Additionally, the amended, appendix C measures AWEF per 
AHRI 1250-2009, and therefore does not contain any changes that will 
require retesting or rerating. The current testing costs which DOE have 
determined will be equivalent to the amended appendix C testing costs 
are summarized in this section. DOE's assessment of the impacts of the 
amendments of appendix C to include new test procedures for high-
temperature refrigeration systems and CO2 unit coolers are 
discussed in more detail in this section.
    In response to the April 2022 NOPR, HTPG agreed that proposals to 
appendix C will not be unduly burdensome or impact cost. (HTPG, No. 32 
at p. 8)
    DOE is also adopting certain changes in the new appendix C1 that 
will amend the existing test procedure for walk-in coolers and freezers 
by:
     Expanding the off-cycle refrigeration system power 
measurements;
     Adding methods of test for single-packaged dedicated 
systems; and
     Including a method for testing ducted systems.
    DOE has determined that these amendments will improve the 
representativeness, accuracy, and reproducibility of the test results, 
and will not be unduly burdensome for manufacturers to conduct. DOE has 
also determined that these amendments will impact testing costs by 
equipment type. DOE does not anticipate that the remainder of the 
amendments adopted in this final rule would impact test costs or test 
burden. DOE estimates third-party costs for testing to the current DOE 
test procedure to be:
     $10,000 for outdoor low-temperature and medium-temperature 
dedicated condensing units tested alone;
     $6,500 for indoor low-temperature and medium-temperature 
dedicated condensing units tested alone;
     $6,500 for low-temperature unit coolers tested alone;
     $6,000 for medium-temperature unit coolers tested alone;
     $10,000 for single-packaged dedicated systems; and
     $10,000 for high-temperature matched pairs.
    As discussed previously in section III.G.1 of this document, DOE is 
adopting off-cycle test provisions in AHRI 1250-2020 for walk-in cooler 
and freezer refrigeration systems. The current test procedure requires 
off-cycle power to be measured at a single ambient condition (i.e., 90 
[deg]F). The new test procedure requires off-cycle to be measured at 
three different ambient conditions (i.e., 95 [deg]F, 59 [deg]F, and 35 
[deg]F) for outdoor dedicated condensing units, outdoor matched pair 
systems, and outdoor dedicated systems. The matched-pair and single-
packaged dedicated systems include high-temperature refrigeration 
systems. When the waivers for these high-temperature refrigeration 
systems were granted, only one off-cycle test was required; therefore, 
manufacturers with waivers would be required to conduct additional 
testing compared to the alternate test procedure currently required. 
DOE estimates that measuring off-cycle power at these additional 
ambient conditions may increase third-party lab test cost by $1,000 per 
unit to a total cost of $11,000 per unit for outdoor dedicated 
condensing units, outdoor matched-pair systems, and outdoor single-
packaged dedicated systems.
    Manufacturers are not required to perform laboratory testing on all 
basic models. In accordance with 10 CFR 429.53, WICF refrigeration 
system manufacturers may elect to use AEDMs. DOE estimates the per-
manufacturer cost to develop and validate an AEDM for outdoor dedicated 
condensing units and outdoor matched-pair systems to be $24,600.\62\ 
DOE estimates an additional cost of approximately $46 per basic model 
\63\ for determining energy efficiency of a given basic model using the 
validated AEDM.
---------------------------------------------------------------------------

    \62\ Outdoor single-packaged systems are also impacted by the 
proposed adoption of the AHRI 1250-2020 single-packaged test 
procedure for walk-in cooler and freezer refrigeration systems. The 
combined potential cost increase for outdoor single-packaged systems 
is presented in the next paragraph.
    \63\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    As discussed previously in section III.G.2, DOE is adopting the 
single-packaged dedicated system test procedure for walk-ins in AHRI 
1250-2020. The procedure requires air enthalpy tests to be used as the 
primary test method. In the current test procedure, single-packaged 
dedicated systems use refrigerant enthalpy as the primary test method. 
DOE does not estimate a difference in physical testing costs between 
air and refrigerant enthalpy testing of single-packaged units. DOE 
estimates the per-unit third-party lab test cost to be $11,000 for 
outdoor single-packaged dedicated

[[Page 28826]]

systems and $6,500 for indoor single-packaged dedicated systems. 
However, should a manufacturer choose to use an AEDM, it may incur 
additional costs regarding the development and validation of new AEDMs 
for single-packaged dedicated systems. DOE estimates the per-
manufacturer cost to develop and validate an AEDM to be $24,600 for 
outdoor single-packaged units and $15,600 for indoor single-packaged 
units. DOE estimates an additional cost of approximately $46 per basic 
model \64\ for determining energy efficiency using the validated AEDM.
---------------------------------------------------------------------------

    \64\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    As discussed in sections III.F.6 and III.G.6, DOE is adopting test 
procedures for CO2 unit coolers and high-temperature 
refrigeration systems. DOE estimates that the average third-party lab 
per unit test cost would be $11,000 for a high-temperature matched-pair 
or single-packaged dedicated system, $6,000 for a high-temperature unit 
cooler tested alone, $6,500 for a low-temperature CO2 unit 
cooler, and $6,000 for a medium-temperature CO2 unit cooler. 
As discussed previously, DOE has granted waivers to certain 
manufacturers for both high-temperature refrigeration systems and 
CO2 unit coolers. The test procedures being adopted are 
consistent with the alternate test procedures included in the granted 
waivers. For those manufacturers who have been granted a test procedure 
waiver for this equipment, DOE expects that there would be no 
additional test burden. However, DOE expects that there would be 
additional testing costs for any manufacturers of these products who 
have not submitted or been granted a test procedure waiver at the time 
this test procedure is finalized. Such companies may incur an 
additional per unit test cost of:
     $11,000 for a high-temperature matched-pair or single-
packaged system;
     $6,000 for a high-temperature unit cooler tested alone;
     $6,500 for a low-temperature CO2 unit cooler 
tested alone; and
     $6,000 for a medium-temperature CO2 unit cooler 
tested alone.
    In the April 2022 NOPR, DOE requested comment on its understanding 
of the impact of the test procedure proposals for refrigeration 
systems. 87 FR 23920, 23976.
    AHRI commented that a third-party lab test of a low-temperature 
unit cooler would be two to three times more expensive than DOE's 
$6,500 estimate. (AHRI, No. 30 at p. 12) Lennox stated that, in 
general, DOE's amendments increase work content of the test and 
therefore increase test costs. (Lennox, No. 35 at p. 8) Lennox also 
stated that the costs of their third-party lab tests have been at least 
double DOE's estimates. Id. RSG commented that it considers DOE's 
estimates to be very low and stated that there are few outside labs 
capable of testing to the degree that DOE requires. (RSG, No. 41 at p. 
3) AHRI-Wine stated that they believe the estimated testing burden is 
reasonable and consistent. (AHRI-Wine, No. 30 at p. 4) DOE notes that 
the estimated test costs were based on actual lab quotes, which DOE has 
determined are representative of the pricing available to the industry 
as a whole. Additionally, DOE is aware of third-party labs that have 
the capability to test to the current DOE test procedure.
    HTPG disagreed with DOE's test cost estimates for AEDMs and stated 
that 40 hours of labor per refrigerant is more accurate and therefore 
test costs would be multiplied by the number of refrigerants. (HTPG, 
No. 32 at p. 8) HTPG also stated that more validation would be done by 
manufacturers than what was estimated to ensure an AEDM applies across 
a basic model family. Id.
    DOE notes that the estimated AEDM cost is per AEDM and does not 
make assumptions about the number of AEDMs needed based on the 
refrigerants used by a given manufacturer. DOE used the minimum number 
of tests (two) needed to validate an AEDM. While manufacturers may 
choose to test more units to validate an AEDM, testing more than two is 
not required.
    AHRI stated that small original equipment manufacturers (``OEMs'') 
represent a significant amount of the market and will be negatively 
impacted by added complexity and costs. (AHRI, No. 30 at p. 12) NAFEM 
encouraged DOE to consider the limitation of lab capacity and the 
financial impacts on small businesses. (NAFEM, No. 33 at p. 2) DOE 
specifically discusses the test procedure burden imposed on small 
businesses in section IV.B of this document.
    AHRI stated that EPA and DOE regulations will impact small 
refrigeration OEMs in a relatively immediate time frame. (AHRI, No. 30 
at p. 12) NAFEM also commented that DOE should evaluate how various EPA 
rulemakings may impact energy efficiency improvements in the WICF 
manufacturing process and available products. (NAFEM, No. 33 at p. 2) 
DOE acknowledges that while there are other regulations that impact 
walk-in equipment, DOE will take cumulative regulatory burden into 
account in the ongoing energy conservation standards rulemaking as part 
of its manufacturer impact analysis.
    AHRI and Lennox commented that the test cost estimates should 
include freight cost, unit cost, and cost of a unit to run the test. 
(AHRI, No. 30 at p. 12; Lennox, No. 35 at p. 8) DOE acknowledges that 
freight costs are an additional expense associated with third-party 
testing. DOE has determined that the DOE test procedure is non-
destructive and that units can therefore be recovered after testing. 
For this reason, DOE has estimated the cost of round-trip freight, but 
does not include the cost of the unit under test. Additionally, DOE 
notes that the test procedure does not specifically require use of the 
unit matched to the unit under test (i.e., a dedicated condensing unit 
matched to a unit cooler under test, or a unit cooler matched to a 
dedicated condensing unit under test).
    DOE estimates that the shipping cost for one walk-in unit from a 
manufacturing facility to a test laboratory can range from $250 to 
$1,000 depending on the relative locations of the two facilities, the 
weight and size of the unit being shipped, and the discounts associated 
with shipping multiple units at one time. Thus, DOE estimates the 
round-trip freight costs as ranging from $500 to $2,000.
    DOE additionally notes that it has used third-party laboratory test 
costs for its estimate of test costs. DOE understands that most walk-in 
refrigeration system manufacturers have their own test chambers. In 
these cases, DOE expects that its estimate for test and freight costs 
is conservative.

L. Effective and Compliance Dates

    The effective date for the adopted test procedure amendment will be 
30 days after publication of this final rule in the Federal Register. 
EPCA prescribes that all representations of energy efficiency and 
energy use, including those made on marketing materials and product 
labels, must be made in accordance with an amended test procedure, 
beginning 180 days after publication of the final rule in the Federal 
Register. (42 U.S.C. 6314(d)(1)) EPCA provides an allowance for 
individual manufacturers to petition DOE for an extension of the 180-
day period if the manufacturer may experience undue hardship in meeting

[[Page 28827]]

the deadline. (42 U.S.C. 6314(d)(2)) To receive such an extension, 
petitions must be filed with DOE no later than 60 days before the end 
of the 180-day period and must detail how the manufacturer will 
experience undue hardship. Id. To the extent the modified test 
procedure adopted in this final rule is required only for the 
evaluation and issuance of updated efficiency standards, compliance 
with the amended test procedure does not require use of such modified 
test procedure provisions until the compliance date of updated 
standards.
    Upon the compliance date of test procedure provisions in this final 
rule, any waivers that had been previously issued and are in effect 
that pertain to issues addressed by such provisions are terminated. 10 
CFR 431.404(h)(3). Recipients of any such waivers are required to test 
the products subject to the waiver according to the amended test 
procedure as of the compliance date of the amended test procedure. The 
amendments adopted in this document pertain to issues addressed by 
waivers granted to the manufacturers listed in Table III.8.

                         Table III.8--Manufacturers Granted Waivers and Interim Waivers
----------------------------------------------------------------------------------------------------------------
                                                                                                Proposed test
           Manufacturer                   Subject          Case No.       Relevant test     procedure compliance
                                                                            procedure               date
----------------------------------------------------------------------------------------------------------------
Jamison Door Company.............  PTO for Door Motors.     2017-009  Appendix A..........  10/31/2023.
HH Technologies..................  PTO for Door Motors.     2018-001  Appendix A..........  10/31/2023.
Senneca Holdings.................  PTO for Door Motors.     2020-002  Appendix A..........  10/31/2023.
Hercules.........................  PTO for Door Motors.     2020-013  Appendix A..........  10/31/2023.
HTPG.............................  CO2 Unit Coolers....     2020-009  Appendix C..........  10/31/2023.
Hussmann.........................  CO2 Unit Coolers....     2020-010  Appendix C..........  10/31/2023.
KeepRite.........................  CO2 Unit Coolers....     2020-014  Appendix C..........  10/31/2023.
RefPlus, Inc.....................  CO2 Unit Coolers....     2021-006  Appendix C..........  10/31/2023.
RSG..............................  Multi-Circuit Single-    2022-004  Appendix C..........  10/31/2023.
                                    Package Dedicated
                                    Systems.
LRC Coil.........................  Wine Cellar              2020-024  Appendix C \65\.....  10/31/2023.
                                    Refrigeration
                                    Systems.
Store It Cold....................  Single-Packaged          2018-002  Appendix C1.........  Compliance date of
                                    Dedicated Systems.                                       updated standards.
CellarPro........................  Wine Cellar              2019-009  Appendix C1.........  Compliance date of
                                    Refrigeration                                            updated standards.
                                    Systems.
Air Innovations..................  Wine Cellar              2019-010  Appendix C1.........  Compliance date of
                                    Refrigeration                                            updated standards.
                                    Systems.
Vinotheque.......................  Wine Cellar              2019-011  Appendix C1.........  Compliance date of
                                    Refrigeration                                            updated standards.
                                    Systems.
Vinotemp.........................  Wine Cellar              2020-005  Appendix C1.........  Compliance date of
                                    Refrigeration                                            updated standards.
                                    Systems.
----------------------------------------------------------------------------------------------------------------

IV. Procedural Issues and Regulatory Review
---------------------------------------------------------------------------

    \65\ DOE notes that Table III.15 in the April 2022 NOPR should 
have listed appendix C instead of appendix C1 as the relevant test 
procedure for the LRC Coil waiver. 87 FR 23920, 23977.
---------------------------------------------------------------------------

A. Review Under Executive Orders 12866 and 13563

    Executive Order (``E.O.'') 12866, ``Regulatory Planning and 
Review,'' as supplemented and reaffirmed by E.O. 13563, ``Improving 
Regulation and Regulatory Review,'' 76 FR 3821 (Jan. 21, 2011), 
requires agencies, to the extent permitted by law, to (1) propose or 
adopt a regulation only upon a reasoned determination that its benefits 
justify its costs (recognizing that some benefits and costs are 
difficult to quantify); (2) tailor regulations to impose the least 
burden on society, consistent with obtaining regulatory objectives, 
taking into account, among other things, and to the extent practicable, 
the costs of cumulative regulations; (3) select, in choosing among 
alternative regulatory approaches, those approaches that maximize net 
benefits (including potential economic, environmental, public health 
and safety, and other advantages; distributive impacts; and equity); 
(4) to the extent feasible, specify performance objectives, rather than 
specifying the behavior or manner of compliance that regulated entities 
must adopt; and (5) identify and assess available alternatives to 
direct regulation, including providing economic incentives to encourage 
the desired behavior, such as user fees or marketable permits, or 
providing information upon which choices can be made by the public. DOE 
emphasizes as well that E.O. 13563 requires agencies to use the best 
available techniques to quantify anticipated present and future 
benefits and costs as accurately as possible. In its guidance, the 
Office of Information and Regulatory Affairs (``OIRA'') in the Office 
of Management and Budget (``OMB'') has emphasized that such techniques 
may include identifying changing future compliance costs that might 
result from technological innovation or anticipated behavioral changes. 
For the reasons stated in the preamble, this final regulatory action is 
consistent with these principles.
    Section 6(a) of E.O. 12866 also requires agencies to submit 
``significant regulatory actions'' to OIRA for review. OIRA has 
determined that this final regulatory action does not constitute a 
``significant regulatory action'' under section 3(f) of E.O. 12866. 
Accordingly, this action was not submitted to OIRA for review under 
E.O. 12866.

B. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires 
preparation of a final regulatory flexibility analysis (``FRFA'') for 
any final rule where the agency was first required by law to publish a 
proposed rule for public comment, unless the agency certifies that the 
rule, if promulgated, will not have a significant economic impact on a 
substantial number of small entities. As required by Executive Order 
13272, ``Proper Consideration of Small Entities in Agency Rulemaking,'' 
67 FR 53461 (August 16, 2002), DOE published procedures and policies on 
February 19, 2003, to ensure that the potential impacts of its rules on 
small entities are properly considered during the DOE rulemaking 
process. 68 FR 7990. DOE

[[Page 28828]]

has made its procedures and policies available on the Office of the 
General Counsel's website: www.energy.gov/gc/office-general-counsel. 
DOE reviewed this final rule under the provisions of the Regulatory 
Flexibility Act and the procedures and policies published on February 
19, 2003.
    The Energy Policy and Conservation Act, Public Law 94-163, as 
amended (``EPCA''),\66\ authorizes DOE to regulate the energy 
efficiency of a number of consumer products and certain industrial 
equipment. (42 U.S.C. 6291-6317) Title III, Part C \67\ of EPCA, added 
by Public Law 95-619, Title IV, section 441(a), established the Energy 
Conservation Program for Certain Industrial Equipment, which sets forth 
a variety of provisions designed to improve energy efficiency. This 
equipment includes walk-in coolers and walk-in freezers (collectively 
``WICFs'' or ``walk-ins''), the subject of this document. (42 U.S.C. 
6311(1)(G)) DOE is publishing this final rule in satisfaction of the 7-
year review requirement specified in EPCA. (42 U.S.C. 6314(b)(1))
---------------------------------------------------------------------------

    \66\ All references to EPCA in this document refer to the 
statute as amended through the Energy Act of 2020, Public Law 116-
260 (Dec. 27, 2020), which reflect the last statutory amendments 
that impact Parts A and A-1 of EPCA.
    \67\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
---------------------------------------------------------------------------

    DOE has conducted a focused inquiry into small business 
manufacturers of the equipment covered by this rulemaking. DOE used the 
Small Business Administration's small business size standards to 
determine whether any small entities would be subject to the 
requirements of the rule. The size standards are listed by North 
American Industry Classification System (``NAICS'') code as well as by 
industry description and are available at www.sba.gov/document/support-table-size-standards. Manufacturing WICFs is classified under NAICS 
333415, ``Air-Conditioning and Warm Air Heating Equipment and 
Commercial and Industrial Refrigeration Equipment Manufacturing.'' The 
SBA sets a threshold of 1,250 employees or fewer for an entity to be 
considered as a small business for this category.\68\ DOE used publicly 
available information to identify potential small businesses that 
manufacture WICFs covered in this rulemaking. DOE reviewed its 
Certification Compliance Database (``CCD'') \69\ and the California 
Energy Commission's Modernized Appliance Efficiency Database System 
(``MAEDbS'') \70\ to identify manufacturers. DOE also used 
subscription-based business information tools (e.g., reports from Dun & 
Bradstreet \71\) to determine headcount and revenue of the small 
businesses.
---------------------------------------------------------------------------

    \68\ The size standards are listed by NAICS code and industry 
description and are available at: www.sba.gov/document/support-table-size-standards. (Last accessed Oct. 11, 2022.)
    \69\ U.S. Department of Energy Compliance Certification 
Database, available at www.regulations.doe.gov/certification-data/#q=Product_Group_s%3A*. (Last accessed March 16, 2022.)
    \70\ California Energy Commission's Modernized Appliance 
Efficiency Database System, available at 
cacertappliances.energy.ca.gov/Pages/Search/AdvancedSearch.aspx. 
(Last accessed Nov. 1, 2021.)
    \71\ D&B Hoovers reports are available at app.dnbhoovers.com. 
(Last accessed Oct. 12, 2022.)
---------------------------------------------------------------------------

    Using these data sources, DOE identified 78 original equipment 
manufacturers (``OEMs'') of WICFs that could be potentially affected by 
this rulemaking. DOE screened out companies that do not meet the 
definition of a ``small business'' or are foreign-owned and operated. 
Of these 78 OEMs, 57 are small, domestic manufacturers. DOE notes that 
some manufacturers may produce more than one of the principal 
components of WICFs: doors, panels, and refrigeration systems. Forty-
one of the small, domestic OEMs manufacture doors; 35 of the small, 
domestic OEMs manufacture panels; and 18 of the small, domestic OEMs 
manufacture refrigeration systems.
    In response to the Initial Regulatory Flexibility Analysis 
published as part of the April 2022 NOPR, AHRI noted that while they 
are unsure of the exact number of small OEMs of WICF panels, doors, and 
refrigeration systems, they acknowledge that small OEMs represent a 
significant portion of the WICF market. AHRI asserted that small OEMs 
would be negatively impacted by what AHRI characterized as the added 
complexity and related costs. AHRI also noted that EPA and DOE 
regulatory actions that are not yet fully resolved have impact in a 
relatively immediate timeframe. (AHRI, No. 30 at p. 12)
    DOE agrees with AHRI that small businesses account for the majority 
of WICF component OEMs operating in the United States. Regarding AHRI's 
concerns about complexity, DOE evaluates test procedures for each type 
of covered equipment, including WICFs, to determine whether amended 
test procedures would more accurately or fully comply with the 
requirements for the test procedures to not be unduly burdensome to 
conduct and be reasonably designed to produce test results that reflect 
energy efficiency, energy use, and estimated operating costs during a 
representative average use cycle. (42 U.S.C. 6314(a)(1)) DOE has 
determined that the amendments in this final rule would improve the 
accuracy, reproducibility, and representativeness of test procedure 
results, and will not be unduly burdensome for manufacturers to 
conduct. DOE has determined that the amendments outlined in this final 
rule will not require retesting or rerating of units.
    Regarding the impact of EPA refrigerant regulation and other DOE 
rulemaking actions on small businesses, DOE would consider the impact 
on manufacturers of multiple product/equipment-specific regulatory 
actions pursuant to section 13(g) in appendix A to subpart C of part 
430, in any subsequent energy conservation standards rulemaking 
analysis for WICFs.
    RSG commented that it considers DOE's door, panel, and 
refrigeration system cost estimates to be very low. For refrigeration 
systems, RSG further stated that there are few outside labs capable of 
testing to the degree that DOE requires. (RSG, No. 41 at p. 3) DOE 
notes that the estimated test costs were based on actual laboratory 
quotes, which DOE has determined are representative of the pricing 
available to the industry as a whole. Additionally, DOE is aware of 
third-party laboratories that have the capability to test to the 
current DOE test procedure.
Doors
    DOE has determined that retesting and recertification would not be 
required for walk-in cooler and freezer doors as a result of this 
rulemaking. DOE is adopting the following amendments to appendix A for 
walk-in cooler and freezer doors:
    1. Referencing NFRC 102-2020 for the determination of U-factor;
    2. Including AEDM provisions for manufacturers to alternately 
determine the total energy consumption of display and non-display 
doors;
    3. Providing additional detail for determining the area used to 
convert U-factor into conduction load, As, to differentiate 
it from the area used to determine compliance with the standards, 
Add or And; and
    4. Specifying a PTO value of 97 percent for door motors.
    DOE has determined that these amendments would not increase testing 
costs per basic model relative to the current DOE test procedure in 
appendix A.\72\ Items 1 and 3, referencing NFRC

[[Page 28829]]

102-2020 and additional detail on the area used to convert U-factor 
into a conduction load, improves the consistency, reproducibility, and 
representativeness of test procedure results. Item 2, including AEDM 
provisions, intends to provide manufacturers with the flexibility to 
use an alternative method that gives the best agreement for their 
doors. Item 4, by including a PTO value of 97 percent, intends to 
provide a more representative and consistent means for comparison of 
walk-in door performance for doors with motors.
---------------------------------------------------------------------------

    \72\ DOE estimates the cost of one test to determine energy 
consumption of a walk-in door, including one physical U-factor test 
per NFRC 102-2020, to be $5,000. Per the sampling requirements 
specified at 10 CFR 429.53(a)(3)(ii) and 429.11(b), manufacturers 
are required to test at least two units to determine the rating for 
a basic model, except where only one unit of the basic model is 
produced.
---------------------------------------------------------------------------

    DOE expects certification costs for door manufacturers would either 
remain the same or be reduced, depending on whether manufacturers have 
been able to achieve the agreement between U-factors simulated using 
the method in NFRC 100 and U-factors tested using NFRC 102. 
Manufacturers of doors that have been able to achieve the specified 
agreement \73\ between U-factors simulated using the method in NFRC 100 
and U-factors tested using NFRC 102 would be able to continue using the 
simulation method in NFRC 100, provided that the simulation method also 
meets the basic requirements proposed for an AEDM in 10 CFR 429.53 and 
429.70(f). For manufacturers of doors that have not been able to 
achieve the specified agreement between U-factors simulated using the 
method in NFRC 100 and U-factors tested using NFRC 102, DOE estimates 
that the test burden would decrease. With the new test procedure, 
manufacturers who would have otherwise been required to physically test 
every walk-in door basic model could develop an AEDM for rating their 
basic models of walk-in doors consistent with the proposed provisions 
in 10 CFR 429.53 and 429.70(f). DOE estimates the per-manufacturer cost 
to develop and validate an AEDM for a single validation class of walk-
in doors to be $11,100, in addition to an estimated $1,600 to $5,000 in 
shipping costs.\74\ DOE estimates an additional cost to determine 
energy consumption of a walk-in door using an AEDM to be $46 per basic 
model.\75\
---------------------------------------------------------------------------

    \73\ Section 4.7.1 of NFRC 100 requires that the accepted 
difference between the tested U-factor and the simulated U-factor be 
(a) 0.03 Btu/(h-ft2 [deg]F) for simulated U-factors that are 0.3 
Btu/(h-ft2 [deg]F) or less, or (b) 10 percent of the simulated U-
factor for simulated U-factors greater than 0.3 Btu/(h-ft2 [deg]F). 
This agreement must match for the baseline product in a product 
line. Per NFRC 100, the baseline product is the individual product 
selected for validation; it is not synonymous with ``basic model'' 
as defined in 10 CFR 431.302.
    \74\ DOE estimates that the shipping cost for a walk-in box, 
typically made up of multiple panels and a door, from a 
manufacturing facility to a test lab can range from $800 to $2,500 
depending on the relative locations of the two facilities, the 
weight and size of the unit being shipped, and the discounts 
associated with shipping multiple units at one time. This means that 
each estimated test cost would increase from $1,600 to $5,000 
dollars when shipping a unit for test to and from a third-party lab.
    \75\ DOE estimated initial costs to validate an AEDM assuming 24 
hours of general time to develop and validate an AEDM based on 
existing simulation tools. DOE estimated the cost of an engineering 
calibration technician fully burdened wage of $46 per hour plus the 
cost of third-party physical testing of two basic models per 
proposed validation class. DOE estimated the additional per basic 
model cost to determine efficiency using an AEDM assuming 1 hour per 
basic model at the cost of an engineering calibration technician 
wage of $46 per hour.
---------------------------------------------------------------------------

    DOE expects that the additional detail provided for determining the 
area used to convert U-factor into conduction load, As, 
would not result in changes that require manufacturers to re-certify 
equipment. Manufacturers would be able to rely on data generated under 
the current test procedure for equipment already certified.
    For walk-in doors with motors, DOE has determined that the 
amendments described in section III of this final rule would either not 
change the measured energy consumption or would result in a lower 
measured energy consumption and therefore, would not require retesting 
or recertification as a result of DOE's adoption of the amendments to 
the test procedures. New testing is only required if the manufacturer 
wishes to make claims using the new, more efficient rating. 
Additionally, DOE has determined the amendments would not increase the 
cost of testing for doors with motors.
    DOE concludes that manufacturers of WICF doors, including small 
manufacturers, will not incur retesting and recertification costs as a 
result of this final rule.
Panels
    In this final rule, DOE is amending the existing test procedure in 
appendix B for measuring the R-value of insulation of panels by:
    1. Incorporating by reference the updated version of the applicable 
industry test method, ASTM C518-17;
    2. Including provisions specific to measurement of test specimen 
and total insulation thickness; and
    3. Providing specifications for determining the parallelism and 
flatness of the test specimen.
    The first item incorporates by reference the most up-to-date 
version of the industry standards currently referenced in the DOE test 
procedure. Items 2 and 3 include additional instructions intended to 
improve consistency and reproducibility of test procedure results.
    DOE has concluded that the amendments will not change efficiency 
ratings for walk-in panels, and therefore will not require rerating as 
result of DOE's adoption of this amendment to the test procedure. 
Therefore, DOE has determined that these amendments will not add any 
additional testing costs to small business manufacturers of WICF 
panels.
Refrigeration Systems
    In this final rule, DOE is adopting changes to appendix C that DOE 
has determined would improve the accuracy and reproducibility of the 
test results and would not be unduly burdensome for manufacturers to 
conduct. DOE has determined that these changes would not impact testing 
cost. Additionally, the amended appendix C, measuring AWEF per AHRI 
1250-2009, does not contain any changes that would require retesting or 
rerating.
    DOE is also adopting, through incorporations by reference, certain 
provisions of AHRI 1250-2020 in appendix C1 that will amend the 
existing test procedure for walk-in cooler and freezer refrigeration 
systems. DOE notes that the new appendix C1, which establishes new 
energy efficiency metric AWEF2, would increase testing costs for 
certain refrigeration system equipment types. This final rule does not 
require manufacturers to rate equipment using appendix C1. If DOE were 
to adopt a future energy conservation standard using the AWEF2 metric, 
that energy conversation standard will cause manufacturers to incur 
costs for retesting and recertification at the time when the amended 
standards take effect. The cost of retesting and recertification based 
on appendix C1 would be incorporated into the analysis of the energy 
conservation standard adopting the AWEF2 metric, should DOE choose to 
establish standard using that metric.
    Although this test procedure final rule does not require the use of 
appendix C1 and manufacturers, including small manufacturers, will not 
incur retesting or recertification costs based on the AWEF2 metric at 
this time, DOE discusses the potential impacts of adopting certain 
changes in the new appendix C1 in this section.

[[Page 28830]]

    As discussed previously in this final rule, DOE is adopting off-
cycle test provisions in AHRI 1250-2020 for walk-in refrigeration 
systems. The current test procedure requires off-cycle power to be 
measured at the 95 [deg]F ambient condition. The new test procedure 
requires off-cycle to be measured at 95 [deg]F, 59 [deg]F, and 35 
[deg]F ambient conditions for outdoor dedicated condensing units, 
outdoor matched pair systems, and outdoor dedicated systems. The 
matched pair and single-packaged dedicated systems include high-
temperature refrigeration systems. When the waivers for these high-
temperature refrigeration systems were granted, only one off-cycle test 
was required; therefore, manufacturers with waivers would be required 
to conduct additional testing as compared to the alternate test 
procedure currently required. DOE estimates that measuring off-cycle 
power at these additional ambient conditions may increase third-party 
lab test cost by $1,000 per unit to a total cost of $11,000 per unit 
for outdoor dedicated condensing units, outdoor matched pair systems, 
and outdoor single-packaged dedicated systems. The physical testing 
cost would be $22,000 per basic model for outdoor dedicated condensing 
units, outdoor matched pair systems, and outdoor single-packaged 
dedicated systems, in addition to an estimated $1,000 to $4,000 in 
round trip shipping costs.\76\
---------------------------------------------------------------------------

    \76\ The cost to test one unit is $11,000, plus an estimated 
$500 to $2,000 for shipping the refrigeration system to and from the 
third-party lab. Per the sampling requirements specified at 10 CFR 
429.53(a)(2)(ii) and 429.11(b), manufacturers are required to test 
at least two units to determine the rating for a basic model, except 
where only one unit of the basic model is produced.
---------------------------------------------------------------------------

    However, manufacturers are not required to perform laboratory 
testing on all basic models. In accordance with 10 CFR 429.53, WICF 
refrigeration system manufacturers may elect to use AEDMs. DOE 
estimates the per-manufacturer cost to develop and validate an AEDM for 
outdoor dedicated condensing units and outdoor matched pair systems to 
be approximately $24,581,\77\ in addition to an estimated $1,000 to 
$4,000 in round trip shipping costs.\78\ DOE estimates an additional 
cost of approximately $46 per basic model \79\ for determining energy 
efficiency of a given basic model using the validated AEDM.
---------------------------------------------------------------------------

    \77\ Outdoor single-packaged systems are also impacted by the 
proposed adoption of AHRI 1250-2020 single-packaged test procedure 
for walk-in cooler and freezer refrigeration systems. The combined 
potential cost increase for outdoor single-packaged systems is 
presented in the next paragraph.
    \78\ Shipping costs associated with third-party physical testing 
of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)).
    \79\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    DOE estimated the range of potential costs for the five small OEMs 
that manufacture outdoor dedicated condensing units, outdoor matched 
pair systems, and outdoor single-packaged dedicated systems. When 
developing cost estimates for the small OEMs, DOE considers the cost to 
update the existing AEDM simulation tool, the costs to validate the 
AEDM through physical testing (including shipping costs to and from the 
third-party laboratory), and the cost to rate basic models using the 
AEDM. DOE assumes a high-cost scenario where manufacturers would be 
required to develop AEDMs for six validation classes.
    DOE estimates the impacts based on basic model counts and company 
revenue. Table IV.1 summarizes DOE's estimates for the five identified 
small businesses. On average, testing costs represent less than 1 
percent of annual revenue for a typical small business.
    As previously discussed, the procedure in appendix C1 would only 
require retesting or recertification when and if a future energy 
conservation standard takes effect.

Table IV.1--Potential Small Business Re-Rating Costs (2022$) as a Result
          of Off-Cycle Refrigeration System Power Requirements
------------------------------------------------------------------------
                                                 Estimated
                                    Re-rating      annual     Percent of
        Small domestic OEM           estimate     revenue       annual
                                      ($MM)        ($MM)       revenue
------------------------------------------------------------------------
Manufacturer 1...................         0.16         12.0          1.4
Manufacturer 2...................         0.16        110.3          0.1
Manufacturer 3...................         0.23         88.7          0.3
Manufacturer 4...................         0.16        116.2          0.1
Manufacturer 5...................         0.16        156.3          0.1
------------------------------------------------------------------------

    As also discussed in the final rule, DOE is adopting the single-
packaged dedicated system test procedure for walk-ins in AHRI 1250-
2020. The procedure requires air enthalpy tests to be used as the 
primary test method. In the current test procedure, single-packaged 
dedicated systems use refrigerant enthalpy as the primary test method. 
DOE does not estimate a difference in physical testing costs between 
air and refrigerant enthalpy testing of single-packaged dedicated 
systems. DOE estimates the per-unit third party lab test cost to be 
$11,000 for outdoor single-packaged units and $6,500 for indoor single-
packaged units. The physical testing cost would be $22,000 per basic 
model for outdoor single-packaged dedicated systems and $13,000 per 
basic model for indoor package systems, in addition to an estimated 
$1,000 to $4,000 in round trip shipping costs for each class.\80\
---------------------------------------------------------------------------

    \80\ Per the sampling requirements specified at 10 CFR 
429.53(a)(2)(ii) and 429.11(b), manufacturers are required to test 
at least two units to determine the rating for a basic model, except 
where only one unit of the basic model is produced.
---------------------------------------------------------------------------

    However, should a manufacturer choose to use an AEDM, it may incur 
additional costs regarding the development and validation of new AEDMs 
for single-packaged dedicated systems. DOE estimates the per 
manufacturer cost to develop and validate an AEDM to be $24,580 for 
outdoor single-packaged units and $15,580 for indoor single-packaged 
units, in addition to an estimated $1,000 to $4,000 in round trip 
shipping costs.\81\ DOE estimates an additional cost of

[[Page 28831]]

approximately $46 per basic model \82\ for determining energy 
efficiency using the validated AEDM.
---------------------------------------------------------------------------

    \81\ Shipping costs associated with third-party physical testing 
of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)).
    \82\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    DOE estimated the range of potential costs for the two domestic, 
small OEMs that manufacture single-packaged dedicated systems. When 
developing cost estimates for the small OEMs, DOE considered the cost 
to update the existing AEDM simulation tool, the costs to validate the 
AEDM through physical testing (including shipping costs to and from the 
third-party laboratory), and the cost to rate basic models using the 
AEDM.
    Both small businesses manufacture indoor and outdoor, low- and 
medium-temperature, single-packaged dedicated systems. One small 
business manufactures 28 basic models of single-packaged dedicated 
systems with an estimated annual revenue of $110 million. Therefore, 
DOE estimates the associated re-rating costs for this manufacturer to 
be approximately $91,250 when making use of AEDMs. The cost for this 
manufacturer represents less than 1 percent of annual revenue.
    The second small business manufactures 38 basic models of single-
packaged dedicated systems with an estimated annual revenue of $156 
million. Therefore, DOE estimates the associated re-rating costs for 
this manufacturer to be approximately $91,700 when making use of AEDMs. 
The cost for this manufacturer represents less than 1 percent of annual 
revenue.
    As previously discussed, the procedure in appendix C1 would only 
require retesting or recertification when and if a future energy 
conservation standard takes effect.
    As also discussed in this final rule, DOE is adopting test 
procedures for CO2 unit coolers and high-temperature 
refrigeration systems. DOE estimates that the average third-party lab 
per unit test cost would be $11,000 for a high-temperature matched pair 
or single-packaged dedicated system, $6,000 for a high-temperature unit 
cooler tested alone, $6,500 for a low-temperature CO2 unit 
cooler, and $6,000 for a medium-temperature CO2 unit cooler. 
As discussed previously, DOE has granted waivers to certain 
manufacturers for both high-temperature refrigeration systems and 
CO2 unit coolers. The test procedures being adopted are 
consistent with the alternate test procedures included in the granted 
waivers. For those manufacturers who have been granted a test procedure 
waiver for this equipment, DOE expects that there would be no 
additional test burden. However, DOE expects that there would be 
additional testing costs for any manufacturers of these products who 
have not submitted or been granted a test procedure waiver at the time 
this test procedure is finalized. DOE estimates these manufacturers may 
incur rating expenses up to the following estimates, in addition to an 
estimated $5,000 to $2,000 in shipping costs for each class.\83\
---------------------------------------------------------------------------

    \83\ The cost to ship one unit to and from the third-party lab 
is approximately $500 to $2,000. Per the sampling requirements 
specified at 10 CFR 429.53(a)(2)(ii) and 429.11(b), manufacturers 
are required to test at least two units to determine the rating for 
a basic model, except where only one unit of the basic model is 
produced.
---------------------------------------------------------------------------

     $22,000 per basic model for a high-temperature matched 
pair or single-packaged dedicated system; \84\
---------------------------------------------------------------------------

    \84\ Per the sampling requirements specified at 10 CFR 
429.53(a)(2)(ii) and 429.11(b), manufacturers are required to test 
at least two units to determine the rating for a basic model, except 
where only one unit of the basic model is produced.
---------------------------------------------------------------------------

     $12,000 per basic model for a high-temperature unit cooler 
tested alone; \85\
---------------------------------------------------------------------------

    \85\ Id.
---------------------------------------------------------------------------

     $13,000 per basic model for a low-temperature 
CO2 unit cooler; \86\ and
---------------------------------------------------------------------------

    \86\ Id.
---------------------------------------------------------------------------

     $12,000 per basic model for a medium-temperature 
CO2 unit cooler.\87\
---------------------------------------------------------------------------

    \87\ Id.
---------------------------------------------------------------------------

    However, manufacturers are not required to perform laboratory 
testing on all basic models. In accordance with 10 CFR 429.53, WICF 
refrigeration system manufacturers may elect to use AEDMs. DOE 
estimates the per-manufacturer cost to develop and validate an AEDM for 
high-temperature systems and low- and medium-temperature CO2 
unit coolers to be $24,580 per validation class, in addition to an 
estimated $1,000 to $4,000 in round trip shipping costs.\88\ DOE 
estimates an additional cost of approximately $46 per basic model \89\ 
for determining energy efficiency using the validated AEDM.
---------------------------------------------------------------------------

    \88\ Shipping costs associated with third-party physical testing 
of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)).
    \89\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    DOE estimated the potential costs to manufacturers of high-
temperature units as a result of off-cycle requirements using an AEDM. 
Specifically, DOE estimated the range of potential costs for the five 
identified domestic, small OEMs that manufacture high-temperature 
units. When developing cost estimates for the small OEMs, DOE considers 
the cost to develop the AEDM simulation tool, the costs to validate the 
AEDM through physical testing (including shipping costs to and from the 
third-party laboratory), and the cost to rate basic models using the 
AEDM. DOE assumes a scenario where manufacturers would be required to 
develop AEDMs for three validation classes.
    DOE estimated the impacts based on basic model counts and company 
revenue. Table IV.2 summarizes DOE's estimates for the five identified 
small businesses. On average, testing costs represent approximately 1.3 
percent of annual revenue for a typical small business.
    As previously discussed, the procedure in appendix C1 would only 
require retesting or recertification when and if a future energy 
conservation standard takes effect.

[[Page 28832]]



 Table IV.2--Potential Small Business Re-Rating Costs (2022$) for High-
                    Temperature Refrigeration Systems
------------------------------------------------------------------------
                                                 Estimated
                                    Re-rating      annual     Percent of
        Small domestic OEM           estimate     revenue       annual
                                      ($MM)        ($MM)       revenue
------------------------------------------------------------------------
Manufacturer A...................        0.089          3.9          2.3
Manufacturer B...................        0.088          3.6          2.5
Manufacturer C...................        0.089         11.5          0.8
Manufacturer D...................        0.091         10.8          0.8
Manufacturer E...................        0.089        208.0          0.0
------------------------------------------------------------------------

    Manufacturers of CO2 unit coolers may also choose to 
utilize an AEDM. Furthermore, AEDM unit cooler validation classes do 
not distinguish between CO2 unit coolers and non-
CO2 unit coolers. Therefore, manufacturers of CO2 
unit coolers may use the same validation classes as non-CO2 
unit coolers.
    On the basis that the adopted test procedure changes will not 
require retesting and recertification, DOE certifies that this final 
rule does not have a ``significant economic impact on a substantial 
number of small entities,'' and that the preparation of a FRFA is not 
warranted. DOE will transmit a certification and supporting statement 
of factual basis to the Chief Counsel for Advocacy of the Small 
Business Administration for review under 5 U.S.C. 605(b).

C. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of walk-ins must certify to DOE that their products 
comply with any applicable energy conservation standards. To certify 
compliance, manufacturers must first obtain test data for their 
products according to the DOE test procedures, including any amendments 
adopted for those test procedures. DOE has established regulations for 
the certification and recordkeeping requirements for all covered 
consumer products and commercial equipment, walk-ins. (See generally 10 
CFR part 429.) The collection-of-information requirement for the 
certification and recordkeeping is subject to review and approval by 
OMB under the Paperwork Reduction Act (PRA). This requirement has been 
approved by OMB under OMB Control Number 1910-1400. Public reporting 
burden for the certification is estimated to average 35 hours per 
response, including the time for reviewing instructions, searching 
existing data sources, gathering and maintaining the data needed, and 
completing and reviewing the collection of information.
    DOE is not amending the certification or reporting requirements for 
walk-ins in this final rule. Instead, DOE may consider proposals to 
amend the certification requirements and reporting for walk-ins under a 
separate rulemaking regarding appliance and equipment certification. 
DOE will address changes to OMB Control Number 1910-1400 at that time, 
as necessary.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply with, a collection of information subject to the 
requirements of the PRA, unless that collection of information displays 
a currently valid OMB Control Number.

D. Review Under the National Environmental Policy Act of 1969

    In this final rule, DOE establishes test procedure amendments that 
it expects will be used to develop and implement future energy 
conservation standards for walk-ins. DOE has determined that this rule 
falls into a class of actions that are categorically excluded from 
review under the National Environmental Policy Act of 1969 (42 U.S.C. 
4321 et seq.) and DOE's implementing regulations at 10 CFR part 1021. 
Specifically, DOE has determined that adopting test procedures for 
measuring energy efficiency of consumer products and industrial 
equipment is consistent with activities identified in 10 CFR part 1021, 
appendix A to subpart D, A5 and A6. Accordingly, neither an 
environmental assessment nor an environmental impact statement is 
required.

E. Review Under Executive Order 13132

    Executive Order 13132, ``Federalism,'' 64 FR 43255 (August 4, 
1999), imposes certain requirements on agencies formulating and 
implementing policies or regulations that preempt State law or that 
have federalism implications. The Executive order requires agencies to 
examine the constitutional and statutory authority supporting any 
action that would limit the policymaking discretion of the States and 
to carefully assess the necessity for such actions. The Executive order 
also requires agencies to have an accountable process to ensure 
meaningful and timely input by State and local officials in the 
development of regulatory policies that have Federalism implications. 
On March 14, 2000, DOE published a statement of policy describing the 
intergovernmental consultation process it will follow in the 
development of such regulations. 65 FR 13735. DOE examined this final 
rule and determined that it will not have a substantial direct effect 
on the States, on the relationship between the National Government and 
the States, or on the distribution of power and responsibilities among 
the various levels of government. EPCA governs and prescribes Federal 
preemption of State regulations as to energy conservation for the 
equipment that are the subject of this final rule. States can petition 
DOE for exemption from such preemption to the extent, and based on 
criteria, set forth in EPCA. (42 U.S.C. 6297(d)) No further action is 
required by Executive Order 13132.

F. Review Under Executive Order 12988

    Regarding the review of existing regulations and the promulgation 
of new regulations, section 3(a) of Executive Order 12988, ``Civil 
Justice Reform,'' 61 FR 4729 (Feb. 7, 1996), imposes on Federal 
agencies the general duty to adhere to the following requirements: (1) 
eliminate drafting errors and ambiguity; (2) write regulations to 
minimize litigation; (3) provide a clear legal standard for affected 
conduct rather than a general standard; and (4) promote simplification 
and burden reduction. Section 3(b) of Executive Order 12988 
specifically requires that Executive agencies make every reasonable 
effort to ensure that the regulation (1) clearly specifies the 
preemptive effect, if any; (2) clearly specifies any effect on existing 
Federal law or regulation; (3) provides a clear legal standard for 
affected conduct while promoting simplification and

[[Page 28833]]

burden reduction; (4) specifies the retroactive effect, if any; (5) 
adequately defines key terms; and (6) addresses other important issues 
affecting clarity and general draftsmanship under any guidelines issued 
by the Attorney General. Section 3(c) of Executive Order 12988 requires 
Executive agencies to review regulations in light of applicable 
standards in sections 3(a) and 3(b) to determine whether they are met 
or it is unreasonable to meet one or more of them. DOE has completed 
the required review and determined that, to the extent permitted by 
law, this final rule meets the relevant standards of Executive Order 
12988.

G. Review Under the Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (``UMRA'') 
requires each Federal agency to assess the effects of Federal 
regulatory actions on State, local, and Tribal governments and the 
private sector. Public Law 104-4, sec. 201 (codified at 2 U.S.C. 1531). 
For a regulatory action resulting in a rule that may cause the 
expenditure by State, local, and Tribal governments, in the aggregate, 
or by the private sector of $100 million or more in any one year 
(adjusted annually for inflation), section 202 of UMRA requires a 
Federal agency to publish a written statement that estimates the 
resulting costs, benefits, and other effects on the national economy. 
(2 U.S.C. 1532(a), (b)) The UMRA also requires a Federal agency to 
develop an effective process to permit timely input by elected officers 
of State, local, and Tribal governments on a proposed ``significant 
intergovernmental mandate,'' and requires an agency plan for giving 
notice and opportunity for timely input to potentially affected small 
governments before establishing any requirements that might 
significantly or uniquely affect small governments. On March 18, 1997, 
DOE published a statement of policy on its process for 
intergovernmental consultation under UMRA. 62 FR 12820; also available 
at www.energy.gov/gc/office-general-counsel. DOE examined this final 
rule according to UMRA and its statement of policy and determined that 
the rule contains neither an intergovernmental mandate, nor a mandate 
that may result in the expenditure of $100 million or more in any year, 
so these requirements do not apply.

H. Review Under the Treasury and General Government Appropriations Act, 
1999

    Section 654 of the Treasury and General Government Appropriations 
Act, 1999 (Pub. L. 105-277) requires Federal agencies to issue a Family 
Policymaking Assessment for any rule that may affect family well-being. 
This final rule will not have any impact on the autonomy or integrity 
of the family as an institution. Accordingly, DOE has concluded that it 
is not necessary to prepare a Family Policymaking Assessment.

I. Review Under Executive Order 12630

    DOE has determined, under Executive Order 12630, ``Governmental 
Actions and Interference with Constitutionally Protected Property 
Rights,'' 53 FR 8859 (March 18, 1988), that this regulation will not 
result in any takings that might require compensation under the Fifth 
Amendment to the U.S. Constitution.

J. Review Under Treasury and General Government Appropriations Act, 
2001

    Section 515 of the Treasury and General Government Appropriations 
Act, 2001 (44 U.S.C. 3516 note) provides for agencies to review most 
disseminations of information to the public under guidelines 
established by each agency pursuant to general guidelines issued by 
OMB. OMB's guidelines were published at 67 FR 8452 (Feb. 22, 2002), and 
DOE's guidelines were published at 67 FR 62446 (Oct. 7, 2002). Pursuant 
to OMB Memorandum M-19-15, Improving Implementation of the Information 
Quality Act (April 24, 2019), DOE published updated guidelines which 
are available at www.energy.gov/sites/prod/files/2019/12/f70/DOE%20Final%20Updated%20IQA%20Guidelines%20Dec%202019.pdf. DOE has 
reviewed this final rule under the OMB and DOE guidelines and has 
concluded that it is consistent with applicable policies in those 
guidelines.

K. Review Under Executive Order 13211

    Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355 
(May 22, 2001), requires Federal agencies to prepare and submit to OMB, 
a Statement of Energy Effects for any significant energy action. A 
``significant energy action'' is defined as any action by an agency 
that promulgated or is expected to lead to promulgation of a final 
rule, and that (1) is a significant regulatory action under Executive 
Order 12866, or any successor order; and (2) is likely to have a 
significant adverse effect on the supply, distribution, or use of 
energy; or (3) is designated by the Administrator of OIRA as a 
significant energy action. For any significant energy action, the 
agency must give a detailed statement of any adverse effects on energy 
supply, distribution, or use if the regulation is implemented, and of 
reasonable alternatives to the action and their expected benefits on 
energy supply, distribution, and use.
    This regulatory action is not a significant regulatory action under 
Executive Order 12866. Moreover, it would not have a significant 
adverse effect on the supply, distribution, or use of energy, nor has 
it been designated as a significant energy action by the Administrator 
of OIRA. Therefore, it is not a significant energy action, and, 
accordingly, DOE has not prepared a Statement of Energy Effects.

L. Review Under Section 32 of the Federal Energy Administration Act of 
1974

    Under section 301 of the Department of Energy Organization Act 
(Pub. L. 95-91; 42 U.S.C. 7101), DOE must comply with section 32 of the 
Federal Energy Administration Act of 1974, as amended by the Federal 
Energy Administration Authorization Act of 1977. (15 U.S.C. 788; 
``FEAA'') Section 32 essentially provides in relevant part that, where 
a rule authorizes or requires use of commercial standards, the 
rulemaking must inform the public of the use and background of such 
standards. In addition, section 32(c) requires DOE to consult with the 
Attorney General and the Chairman of the Federal Trade Commission 
(``FTC'') concerning the impact of the commercial or industry standards 
on competition.
    The modifications to the test procedure for walk-ins adopted in 
this final rule incorporates testing methods contained in certain 
sections of the following commercial standards: NFRC 102-2020, ASTM 
C1199-14, ASTM C518-17, AHRI 1250-2020, AHRI 1250-2020, ANSI/ASHRAE 37-
2009, and ANSI/ASHRAE 16-2016. DOE has evaluated these standards and is 
unable to conclude whether it fully complies with the requirements of 
section 32(b) of the FEAA (i.e., whether it was developed in a manner 
that fully provides for public participation, comment, and review). DOE 
has consulted with both the Attorney General and the Chairman of the 
FTC about the impact on competition of using the methods contained in 
these standards.

M. Congressional Notification

    As required by 5 U.S.C. 801, DOE will report to Congress on the 
promulgation of this rule before its effective date. The report will 
state that it has been determined that the rule is not a ``major rule'' 
as defined by 5 U.S.C. 804(2).

[[Page 28834]]

N. Description of Materials Incorporated by Reference

    AHRI Standard 1250 (I-P)-2009 is an industry-accepted test 
procedure for measuring the performance of walk-in cooler and walk-in 
freezer refrigeration systems. Specifically, the test procedure 
codified by this final rule references AHRI 1250-2009 for testing walk-
in refrigeration units. AHRI 1250-2009 is reasonably available on 
AHRI's website at www.ahrinet.org/standards/search-standards.
    AHRI Standard 1250-2020 is an industry-accepted test procedure for 
measuring the performance of walk-in cooler and walk-in freezer 
refrigeration systems. Specifically, the test procedure codified by 
this final rule references AHRI 1250-2020 for testing walk-in 
refrigeration units. AHRI 1250-2020 is reasonably available on AHRI's 
website at www.ahrinet.org/standards/search-standards.
    ANSI/AHRI Standard 420-2008 is an industry-accepted test procedure 
for rating the performance of forced-circulation free-delivery unit 
coolers for refrigeration and is referenced by AHRI 1250-2009. 
Specifically, the test procedure codified by this final rule references 
AHRI 420-2008 for the information that should be recorded when testing 
unit coolers. AHRI 420-2008 is reasonably available on AHRI's website 
at www.ahrinet.org/standards/search-standards.
    ANSI/ASHRAE Standard 16-2016 is an industry-accepted test procedure 
for measuring cooling and heating capacity of room air conditioners, 
packaged terminal air conditioners, and packaged terminal heat pumps 
and is referenced by AHRI 1250-2020. Specifically, the test procedure 
codified by this final rule references ANSI/ASHRAE 16-2016 for test 
provisions related the capacity measurement of single-packaged 
dedicated systems for the appendix C1 test procedure. ANSI/ASHRAE 16-
2016 is reasonably available on ASHRAE's website at www.ashrae.org.
    ANSI/ASHRAE Standard 23.1-2010 is an industry-accepted test 
procedure for rating the performance of positive displacement 
refrigerant compressors and condensing units that operate at 
refrigerant subcritical temperatures and is referenced by AHRI 1250-
2009 and AHRI 1250-2020. Specifically, the test procedure codified by 
this final rule references ANSI/ASHRAE 23.1-2010 for test provisions 
related to capacity measurement of condensing units using the 
compressor calibration method. ANSI/ASHRAE 23.1-2010 is reasonably 
available on ASHRAE's website at www.ashrae.org.
    ANSI/ASHRAE Standard 37-2009 is an industry-accepted test procedure 
for testing and rating air-conditioning and heat pump equipment and is 
referenced by AHRI 1250-2020. Specifically, the test procedure codified 
by this final rule references ANSI/ASHRAE 37-2009 for test provisions 
related to capacity measurement of single-packaged dedicated systems 
for the appendix C1 test procedure. ANSI/ASHRAE 37-2009 is reasonably 
available on ASHRAE's website at www.ashrae.org.
    ANSI/ASHRAE Standard 41.1-2013 is an industry-accepted test 
procedure for measuring temperature and is referenced by AHRI 1250-
2020. Specifically, the test procedure codified by this final rule 
references ANSI/ASHRAE 41.1-2013 for temperature measurements for all 
refrigeration unit tests. ANSI/ASHRAE 41.1-2013 is reasonably available 
on ASHRAE's website at www.ashrae.org.
    ANSI/ASHRAE Standard 41.3-2014 is an industry-accepted test 
procedure for measuring pressure and is referenced by AHRI 1250-2020. 
Specifically, the test procedure codified by this final rule references 
ANSI/ASHRAE 41.3-2014 for pressure measurements for all refrigeration 
unit tests. ANSI/ASHRAE 41.3-12014 is reasonably available on ASHRAE's 
website at www.ashrae.org.
    ANSI/ASHRAE Standard 41.6-2014 is an industry-accepted test 
procedure for measuring humidity and is referenced by AHRI 1250-2020. 
Specifically, the test procedure codified by this final rule references 
ANSI/ASHRAE 41.6-2014 for test provisions related to capacity 
measurement of single-packaged dedicated systems for the appendix C1 
test procedure. ANSI/ASHRAE 41.6-2014 is reasonably available on 
ASHRAE's website at www.ashrae.org.
    ANSI/ASHRAE Standard 41.10-2013 is an industry-accepted test 
procedure for measuring the mass flow of volatile refrigerants with 
flowmeter test methods and is referenced by AHRI 1250-2020. 
Specifically, the test procedure codified by this final rule references 
ANSI/ASHRAE 41.10-2013 for measuring the flow rates of volatile 
refrigerants with flow meters for all refrigeration unit tests. ANSI/
ASHRAE 41.10-2013 is reasonably available on ASHRAE's website at 
www.ashrae.org.
    ASTM C518-17 is an industry-accepted test procedure for measuring 
thermal transmission properties using a heat flow meter apparatus. 
Specifically, the test procedure codified by this final rule references 
ASTM C518-17 for testing walk-in envelope components. ASTM C518-17 is 
reasonably available on ASTM's website at www.astm.org.
    ASTM C1199-14 is an industry-accepted test procedure for measuring 
the steady state thermal transmittance of fenestration systems and is 
referenced by NFRC 102-2020. Specifically, the test procedure codified 
by this final rule references ASTM C1199-14 for testing walk-in 
envelope components. ASTM C1199-14 is reasonably available on ASTM's 
website at www.astm.org.
    NFRC 102-2020 [E0A0], is an industry-accepted test procedure for 
measuring the steady state thermal transmittance of fenestration 
systems. Specifically, the test procedure codified by this final rule 
references NFRC 102-2020 for testing walk-in envelope components. NFRC 
102-2020 is reasonably available on NFRC's website at www.nfrc.org.

V. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this final 
rule.

List of Subjects

10 CFR Part 429

    Administrative practice and procedure, Confidential business 
information, Energy conservation, Household appliances, Imports, 
Intergovernmental relations, Reporting and recordkeeping requirements, 
Small businesses.

10 CFR Part 431

    Administrative practice and procedure, Confidential business 
information, Energy conservation test procedures, Incorporation by 
reference, Reporting and recordkeeping requirements.

Signing Authority

    This document of the Department of Energy was signed on April 12, 
2023, by Francisco Alejandro Moreno, Acting Assistant Secretary for 
Energy Efficiency and Renewable Energy, pursuant to delegated authority 
from the Secretary of Energy. That document with the original signature 
and date is maintained by DOE. For administrative purposes only, and in 
compliance with requirements of the Office of the Federal Register, the 
undersigned DOE Federal Register Liaison Officer has been authorized to 
sign and submit the document in electronic format for publication, as 
an official document of the Department of Energy. This administrative 
process in no way alters the legal effect of this document upon 
publication in the Federal Register.


[[Page 28835]]


    Signed in Washington, DC, on April 12, 2023.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.

    For the reasons stated in the preamble, DOE is amending parts 429 
and 431 of chapter II of title 10, Code of Federal Regulations as set 
forth below:

PART 429--CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR CONSUMER 
PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT

0
1. The authority citation for part 429 continues to read as follows:

    Authority: 42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.

0
2. Amend Sec.  429.53 by revising paragraphs (a)(2)(i) and (a)(3) and 
adding paragraph (a)(4) to read as follows:


Sec.  429.53  Walk-in coolers and walk-in freezers.

    (a) * * *
    (2) * * *
    (i) Applicable test procedure. If AWEF or AWEF2 is determined by 
testing, test according to the applicable provisions of Sec.  
431.304(b) of this chapter with the following equipment-specific 
provisions.
    (A) Dedicated condensing units. Outdoor dedicated condensing 
refrigeration systems that are also designated for use in indoor 
applications must be tested and rated as both an outdoor dedicated 
condensing refrigeration system and an indoor dedicated refrigeration 
system.
    (B) Matched refrigeration systems. A matched refrigeration system 
is not required to be rated if the constituent unit cooler(s) and 
dedicated condensing unit have been tested as specified in Sec.  
431.304(b)(4) of this chapter. However, if a manufacturer wishes to 
represent the efficiency of the matched refrigeration system as 
distinct from the efficiency of either constituent component, or if the 
manufacturer cannot rate one or both of the constituent components 
using the specified method, the manufacturer must test and rate the 
matched refrigeration system as specified in Sec.  431.304(b)(4) of 
this chapter.
    (C) Detachable single-packaged dedicated systems. Detachable 
single-packaged dedicated systems must be tested and rated as a single-
packaged dedicated systems using the test procedure in Sec.  
431.304(b)(4) of this chapter.
    (D) Attached split systems. Attached split systems must be tested 
and rated as dedicated condensing units and unit coolers using the test 
procedure in Sec.  431.304(b)(4) of this chapter.
* * * * *
    (3) For each basic model of walk-in cooler and walk-in freezer 
display and non-display door, the daily energy consumption must be 
determined by testing, in accordance with Sec.  431.304 of this chapter 
and the provisions of this section, or by application of an AEDM that 
meets the requirements of Sec.  429.70 and the provisions of this 
section.
    (i) Applicable test procedure. Prior to October 31, 2023 use the 
test procedure for walk-ins in 10 CFR part 431, subpart R, appendix A, 
revised as of January 1, 2022, to determine daily energy consumption. 
Beginning October 31, 2023, use the test procedure in part 431, subpart 
R, appendix A of this chapter to determine daily energy consumption.
    (ii) Units to be tested. For each basic model, a sample of 
sufficient size shall be randomly selected and tested to ensure that 
any represented value of daily energy consumption of a basic model or 
other measure of energy use for which consumers would favor lower 
values shall be greater than or equal to the higher of:
    (A) The mean of the sample, where:

Equation 3 to Paragraph (a)(3)(ii)(A)
[GRAPHIC] [TIFF OMITTED] TR04MY23.000

    And x is the sample mean, n is the number of samples, and 
xi is the ith sample; or,
    (B) The upper 95 percent confidence limit (UCL) of the true mean 
divided by 1.05, where:

Equation 4 to Paragraph (a)(3)(ii)(B)
[GRAPHIC] [TIFF OMITTED] TR04MY23.001

    And x is the sample mean, s is the sample standard deviation; n is 
the number of samples, and t-0.95 is the statistic for a 95 
percent one-tailed confidence interval with n-1 degrees of freedom 
(from appendix A to this subpart).
    (4) For each basic model of walk-in cooler and walk-in freezer 
panel and non-display door, the R-value must be determined by testing, 
in accordance with Sec.  431.304 of this chapter and the provisions of 
this section.
    (i) Applicable test procedure. Prior to October 31, 2023, use the 
test procedure for walk-ins in 10 CFR part 431, subpart R, appendix B, 
revised as of January 1, 2022, to determine R-value. Beginning October 
31, 2023, use the test procedure in appendix B to subpart R of part 431 
of this chapter to determine R-value.
    (ii) Units to be tested. For each basic model, a sample of 
sufficient size shall be randomly selected and tested to ensure that 
any represented value of R-value or other measure of efficiency of a 
basic model for which consumers would favor higher values shall be less 
than or equal to the lower of:
    (A) The mean of the sample, where:

Equation 5 to Paragraph (a)(4)(ii)(A)
[GRAPHIC] [TIFF OMITTED] TR04MY23.002

    And x is the sample mean, n is the number of samples, and 
xi is the ith sample; or,
    (B) The lower 95 percent confidence limit (LCL) of the true mean 
divided by 0.95, where:

Equation 6 to Paragraph (a)(4)(ii)(B)
[GRAPHIC] [TIFF OMITTED] TR04MY23.003

    And x is the sample mean, s is the sample standard deviation; n is 
the number of samples, and t-0.95 is the statistic for a 95 
percent one-tailed confidence interval with n-1 degree of freedom (from 
appendix A to this subpart).
* * * * *

0
3. Amend Sec.  429.70 by:
0
a. Adding a heading for the table in paragraph (c)(5)(viii)(A);
0
b. Renumbering tables 7 and 8 in paragraphs (m)(5)(vi) and 
(m)(5)(viii)(A), respectively, as tables 9 and 10;
0
c. Revising the heading to paragraph (f) and paragraphs (f)(2)(ii)(A) 
and (B);
0
d. Adding paragraphs (f)(2)(ii)(C) and (f)(2)(iii)(E);
0
e. Revising paragraphs (f)(2)(iv) and (f)(5)(vi); and
0
f. Adding a heading for the table in paragraph (h)(2)(iv).
    The revisions and additions read as follows:


Sec.  429.70  Alternative methods for determining energy efficiency and 
energy use.

* * * * *
    (c) * * *
    (5) * * *
    (viii) * * *
    (A) * * *

Table 3 to Paragraph (c)(5)(viii)(A)

* * * * *
    (f) Alternative efficiency determination method (AEDM) for walk-

[[Page 28836]]

in refrigeration systems and doors-- * * *
    (2) * * *
    (ii) * * *
    (A) For refrigeration systems, which are subject to an energy 
efficiency metric, the predicted efficiency for each model calculated 
by applying the AEDM may not be more than five percent greater than the 
efficiency determined from the corresponding test of the model.
    (B) For doors, which are subject to an energy consumption metric 
the predicted daily energy consumption for each model calculated by 
applying the AEDM may not be more than five percent less than the daily 
energy consumption determined from the corresponding test of the model.
    (C) The predicted energy efficiency or energy consumption for each 
model calculated by applying the AEDM must meet or exceed the 
applicable federal energy conservation standard.
    (iii) * * *
    (E) For rating doors, an AEDM may not simulate or model components 
of the door that are not required to be tested by the DOE test 
procedure. That is, if the test results used to validate the AEDM are 
for the U-factor test of the door, the AEDM must estimate the daily 
energy consumption, specifically the conduction thermal load, and the 
direct and indirect electrical energy consumption, using the nominal 
values and calculation procedure specified in the DOE test procedure.
    (iv) WICF validation classes--(A) Doors.

                   Table 4 to Paragraph (f)(2)(iv)(A)
------------------------------------------------------------------------
                                                   Minimum number of
               Validation class                distinct models that must
                                                       be tested
------------------------------------------------------------------------
Display Doors, Medium Temperature............  2 Basic Models.
Display Doors, Low Temperature...............  2 Basic Models.
Non-display Doors, Medium Temperature........  2 Basic Models.
Non-display Doors, Low Temperature...........  2 Basic Models.
------------------------------------------------------------------------

    (B) Refrigeration systems. (1) For representations made prior to 
the compliance date of revised energy conservation standards for walk-
in cooler and walk-in freezer refrigeration systems, use the following 
validation classes.

                  Table 5 to Paragraph (f)(2)(iv)(B)(1)
------------------------------------------------------------------------
                                                   Minimum number of
               Validation class                distinct models that must
                                                       be tested
------------------------------------------------------------------------
Dedicated Condensing, Medium Temperature,      2 Basic Models.
 Matched Pair Indoor System.
Dedicated Condensing, Medium Temperature,      2 Basic Models.
 Matched Pair Outdoor System \1\.
Dedicated Condensing, Low Temperature,         2 Basic Models.
 Matched Pair Indoor System.
Dedicated Condensing, Low Temperature,         2 Basic Models.
 Matched Pair Outdoor System \1\.
Unit Cooler, High-temperature................  2 Basic Models.
Unit Cooler, Medium Temperature..............  2 Basic Models.
Unit Cooler, Low Temperature.................  2 Basic Models.
Medium Temperature, Indoor Condensing Unit...  2 Basic Models.
Medium Temperature, Outdoor Condensing Unit    2 Basic Models.
 \1\.
Low Temperature, Indoor Condensing Unit......  2 Basic Models.
Low Temperature, Outdoor Condensing Unit \1\.  2 Basic Models.
------------------------------------------------------------------------
\1\ AEDMs validated for an outdoor class by testing only outdoor models
  of that class may be used to determine representative values for the
  corresponding indoor class, and additional validation testing is not
  required. AEDMs validated only for a given indoor class by testing
  indoor models or a mix of indoor and outdoor models may not be used to
  determine representative values for the corresponding outdoor class.

    (2) For representations made on or after the compliance date of 
revised energy conservation standards for walk-in cooler and walk-in 
freezer refrigeration systems, use the following validation classes.

                  Table 6 to Paragraph (f)(2)(iv)(B)(2)
------------------------------------------------------------------------
                                                   Minimum number of
               Validation class                distinct models that must
                                                       be tested
------------------------------------------------------------------------
Dedicated Condensing Unit, Medium              2 Basic Models.
 Temperature, Indoor System.
Dedicated Condensing Unit, Medium              2 Basic Models.
 Temperature, Outdoor System \1\.
Dedicated Condensing Unit, Low Temperature,    2 Basic Models.
 Indoor System.
Dedicated Condensing Unit, Low Temperature,    2 Basic Models.
 Outdoor System \1\.
Single-packaged Dedicated Condensing, High-    2 Basic Models.
 temperature, Indoor System.
Single-packaged Dedicated Condensing, High-    2 Basic Models.
 temperature, Outdoor System \1\.
Single-packaged Dedicated Condensing, Medium   2 Basic Models.
 Temperature, Indoor System.
Single-packaged Dedicated Condensing, Medium   2 Basic Models.
 Temperature, Outdoor System \1\.
Single-packaged Dedicated Condensing, Low      2 Basic Models.
 Temperature, Indoor System.
Single-packaged Dedicated Condensing, Low      2 Basic Models.
 Temperature, Indoor System \1\.
Matched Pair, High-temperature, Indoor         2 Basic Models.
 Condensing Unit.
Matched Pair, High-temperature, Outdoor        2 Basic Models.
 Condensing Unit \1\.
Matched Pair, Medium Temperature, Indoor       2 Basic Models.
 Condensing Unit.
Matched Pair, Medium Temperature, Outdoor      2 Basic Models.
 Condensing Unit \1\.

[[Page 28837]]

 
Matched Pair, Low Temperature, Indoor          2 Basic Models.
 Condensing Unit.
Matched Pair, Low Temperature, Outdoor         2 Basic Models.
 Condensing Unit \1\.
Unit Cooler, High-temperature................  2 Basic Models.
Unit Cooler, Medium Temperature..............  2 Basic Models.
Unit Cooler, Low Temperature.................  2 Basic Models.
------------------------------------------------------------------------
\1\ AEDMs validated for an outdoor class by testing only outdoor models
  of that class may be used to determine representative values for the
  corresponding indoor class, and additional validation testing is not
  required. AEDMs validated only for a given indoor class by testing
  indoor models or a mix of indoor and outdoor models may not be used to
  determine representative values for the corresponding outdoor class.

* * * * *
    (5) * * *
    (vi) Tolerances. For efficiency metrics, the result from a DOE 
verification test must be greater than or equal to the certified rating 
x (1-the applicable tolerance). For energy consumption metrics, the 
result from a DOE verification test must be less than or equal to the 
certified rating x (1 + the applicable tolerance).

                     Table 7 to Paragraph (f)(5)(iv)
------------------------------------------------------------------------
                                                            Applicable
             Equipment                     Metric          tolerance (%)
------------------------------------------------------------------------
Refrigeration systems (including    AWEF/AWEF2..........               5
 components).
Doors.............................  Daily Energy                       5
                                     Consumption.
------------------------------------------------------------------------

* * * * *
    (h) * * *
    (2) * * *
    (iv) * * *

Table 8 to Paragraph (h)(2)(iv)

* * * * *

0
4. Amend Sec.  429.110 by revising paragraph (e)(2) to read as follows:


Sec.  429.110  Enforcement testing.

* * * * *
    (e) * * *
    (2) For automatic commercial ice makers; commercial refrigerators, 
freezers, and refrigerator-freezers; refrigerated bottled or canned 
vending machines; commercial air conditioners and heat pumps; 
commercial packaged boilers; commercial warm air furnaces; commercial 
water heating equipment; and walk-in cooler and walk-in freezer doors, 
panels, and refrigeration systems, DOE will use an initial sample size 
of not more than four units and follow the sampling plans in appendix B 
to this subpart.
* * * * *

0
5. Amend Sec.  429.134 by adding introductory text to paragraph (q) and 
revising paragraphs (q)(2) and (4) to read as follows:


Sec.  429.134  Product-specific enforcement provisions.

* * * * *
    (q) * * * Prior to October 31, 2023, the provisions in 10 CFR 
429.134, revised as of January 1, 2022, are applicable. On and after 
October 31, 2023, the following provisions apply.
* * * * *
    (2) Verification of refrigeration system net capacity. The net 
capacity of the refrigeration system basic model will be measured 
pursuant to the test requirements of part 431, subpart R, appendix C of 
this chapter for each unit tested on and after October 31, 2023, but 
before the compliance date of revised energy conservation standards for 
walk-in cooler and walk-in freezer refrigeration systems. The net 
capacity of the refrigeration system basic model will be measured 
pursuant to the test requirements of part 431, subpart R, appendix C1 
of this chapter for each unit tested on and after the compliance date 
of revised energy conservation standards for walk-in cooler and walk-in 
freezer refrigeration systems. The results of the measurement(s) will 
be averaged and compared to the value of net capacity certified by the 
manufacturer. The certified net capacity will be considered valid only 
if the average measured net capacity is within plus or minus five 
percent of the certified net capacity.
* * * * *
    (4) Verification of door electricity-consuming device power. For 
each basic model of walk-in cooler and walk-in freezer door, DOE will 
calculate the door's energy consumption using the input power listed on 
the nameplate of each electricity-consuming device shipped with the 
door. If an electricity-consuming device shipped with a walk-in door 
does not have a nameplate or the nameplate does not list the device's 
input power, then DOE will use the device's rated input power included 
in the door's certification report. If the door is not certified or if 
the certification does not include a rated input power for an 
electricity-consuming device shipped with a walk-in door, DOE will use 
the measured input power. DOE also may validate the power listed on the 
nameplate or the rated input power by measuring it when energized using 
a power supply that provides power within the allowable voltage range 
listed on the component nameplate or the door nameplate, whichever is 
available. If the measured input power is more than 10 percent higher 
than the input power listed on the nameplate or the rated input power, 
as appropriate, then the measured input power shall be used in the 
door's energy consumption calculation.
    (i) For electricity-consuming devices with controls, the maximum 
input wattage observed while energizing the device and activating the 
control shall be considered the measured input power. For anti-sweat 
heaters that are controlled based on humidity levels, the control may 
be activated by increasing relative humidity in the region of the 
controls without damaging the sensor. For lighting fixtures that are 
controlled with motion sensors, the control may be activated by 
simulating motion in the vicinity of the sensor. Other kinds of 
controls may be activated based on the functions of their sensor.

[[Page 28838]]

    (ii) [Reserved]
* * * * *

PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND 
INDUSTRIAL EQUIPMENT

0
6. The authority citation for part 431 continues to read as follows:

    Authority: 42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.


0
7. Amend Sec.  431.302 by:
0
a. Adding, in alphabetical order, definitions for ``Attached split 
system,'' ``CO2 unit cooler,'' and ``Detachable single-
packaged dedicated system'';
0
b. Revising the definition for ``Door'';
0
c. Adding, in alphabetical order, definitions for ``Door leaf,'' ``Door 
surface area,'' ``Ducted fan coil unit,'' ``Ducted multi-circuit 
single-packaged dedicated system,'' ``Ducted single-packaged dedicated 
system,'' ``High-temperature refrigeration system,'' ``Multi-circuit 
single-packaged dedicated system,'' and ``Non-display door''; and
0
d. Revising the definition of ``Walk-in cooler and walk-in freezer''.
    The additions and revisions read as follows:


Sec.  431.302  Definitions concerning walk-in coolers and walk-in 
freezers.

* * * * *
    Attached split system means a matched pair refrigeration system 
which is designed to be installed with the evaporator entirely inside 
the walk-in enclosure and the condenser entirely outside the walk-in 
enclosure, and the evaporator and condenser are permanently connected 
with structural members extending through the walk-in wall.
* * * * *
    CO2 unit cooler means a unit cooler that includes a 
nameplate listing only CO2 as an approved refrigerant.
* * * * *
* * * * *
    Detachable single-packaged dedicated system means a system 
consisting of a dedicated condensing unit and an insulated evaporator 
section in which the evaporator section is designed to be installed 
external to the walk-in enclosure and circulating air through the 
enclosure wall, and the condensing unit is designed to be installed 
either attached to the evaporator section or mounted remotely with a 
set of refrigerant lines connecting the two components.
* * * * *
    Door means an assembly installed in an opening on an interior or 
exterior wall that is used to allow access or close off the opening and 
that is movable in a sliding, pivoting, hinged, or revolving manner of 
movement. For walk-in coolers and walk-in freezers, a door includes the 
frame (including mullions), the door leaf or multiple leaves (including 
glass) within the frame, and any other elements that form the assembly 
or part of its connection to the wall.
    Door leaf means the pivoting, rolling, sliding, or swinging portion 
of a door.
    Door surface area means the product of the height and width of a 
walk-in door measured external to the walk-in. The height and width 
dimensions shall be perpendicular to each other and parallel to the 
wall or panel of the walk-in to which the door is affixed. The height 
and width measurements shall extend to the edge of the frame and frame 
flange (as applicable) to which the door is affixed. For sliding doors, 
the height and width measurements shall include the track; however, the 
width (for horizontal sliding doors) or the height (for vertical 
sliding doors) shall be truncated to the external width or height of 
the door leaf or leaves and its frame or casings. The surface area of a 
display door is represented as Add and the surface area of a non-
display door is represented as And.
    Ducted fan coil unit means an assembly, including means for forced 
air circulation capable of moving air against both internal and non-
zero external flow resistance, and elements by which heat is 
transferred from air to refrigerant to cool the air, with provision for 
ducted installation.
    Ducted multi-circuit single-packaged dedicated system means a 
ducted single-packaged dedicated system or a ducted single-packaged 
dedicated system (as defined in this section) that contains two or more 
refrigeration circuits that refrigerate a single stream of circulated 
air.
    Ducted single-packaged dedicated system means a refrigeration 
system (as defined in this section) that is a single-packaged assembly 
designed for use with ducts, that includes one or more compressors, a 
condenser, a means for forced circulation of refrigerated air, and 
elements by which heat is transferred from air to refrigerant.
* * * * *
    High-temperature refrigeration system means a refrigeration system 
which is not designed to operate below 45 [deg]F.
* * * * *
    Multi-circuit single-packaged dedicated system means a single-
packaged dedicated system or a ducted single-packaged dedicated system 
(as defined in this section) that contains two or more refrigeration 
circuits that refrigerate a single stream of circulated air.
    Non-display door means a door that is not a display door.
* * * * *
    Walk-in cooler and walk-in freezer means an enclosed storage space 
including, but not limited to, panels, doors, and refrigeration system, 
refrigerated to temperatures, respectively, above, and at or below 32 
degrees Fahrenheit that can be walked into, and has a total chilled 
storage area of less than 3,000 square feet; however, the terms do not 
include products designed and marketed exclusively for medical, 
scientific, or research purposes.
* * * * *

0
8. Revise Sec.  431.303 as follows:


Sec.  431.303  Materials incorporated by reference.

    (a) Certain material is incorporated by reference into this subpart 
with the approval of the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other 
than that specified in this section, the U.S. Department of Energy 
(DOE) must publish a document in the Federal Register and the material 
must be available to the public. All approved incorporation by 
reference (IBR) material is available for inspection at DOE, and at the 
National Archives and Records Administration (NARA). Contact DOE at: 
the U.S. Department of Energy, Office of Energy Efficiency and 
Renewable Energy, Building Technologies Program, Sixth Floor, 950 
L'Enfant Plaza SW, Washington, DC 20024, (202) 586-9127, 
[email protected], www.energy.gov/eere/buildings/building-technologies-office. For information on the availability of this 
material at NARA, email: [email protected], or go to: 
www.archives.gov/federal-register/cfr/ibr-locations.html. The material 
may be obtained from the sources in the following paragraphs of this 
section.
    (b) AHRI. Air-Conditioning, Heating, and Refrigeration Institute, 
2111 Wilson Boulevard, Suite 500, Arlington, VA 22201; (703) 600-0366; 
www.ahrinet.org.
    (1) ANSI/AHRI Standard 420-2008 (``AHRI 420-2008''), Performance 
Rating of Forced-Circulation Free-Delivery Unit Coolers for 
Refrigeration, Copyright 2008; IBR approved for appendix C to subpart 
R.
    (2) AHRI Standard 1250P (I-P)-2009 (``AHRI 1250-2009''), Standard 
for Performance Rating of Walk-in Coolers

[[Page 28839]]

and Freezers, (including Errata sheet dated December 2015), copyright 
2009, except Table 15 and Table 16; IBR approved for appendix C to 
subpart R.
    (3) AHRI Standard 1250 (``AHRI 1250-2020''), Standard for 
Performance Rating of Walk-in Coolers and Freezers, copyright 2020; IBR 
approved for appendix C1 to subpart R.
    (c) ASHRAE. American Society of Heating, Refrigerating and Air-
Conditioning Engineers, 180 Technology Parkway, Peachtree Corners, GA 
30092; (404) 636-8400; www.ashrae.org.
    (1) ANSI/ASHRAE Standard 16-2016 (``ANSI/ASHRAE 16''), Method of 
Testing for Rating Room Air Conditioners, Packaged Terminal Air 
Conditioners, and Packaged Terminal Heat Pumps for Cooling and Heating 
Capacity, ANSI-approved November 1, 2016; IBR approved for appendix C1 
to subpart R.
    (2) ANSI/ASHRAE Standard 23.1-2010 (``ASHRAE 23.1-2010''), Methods 
of Testing for Rating the Performance of Positive Displacement 
Refrigerant Compressors and Condensing Units that Operate at 
Subcritical Temperatures of the Refrigerant, ANSI-approved January 28, 
2010; IBR approved for appendices C and C1 to subpart R.
    (3) ANSI/ASHRAE Standard 37-2009 (``ANSI/ASHRAE 37''), Methods of 
Testing for Rating Electrically Driven Unitary Air-Conditioning and 
Heat Pump Equipment, ASHRAE-approved June 24, 2009; IBR approved for 
appendices C and C1 to subpart R.
    (4) ANSI/ASHRAE Standard 41.1-2013 (``ANSI/ASHRAE 41.1''), Standard 
Method for Temperature Measurement, ANSI-approved January 30, 2013; IBR 
approved for appendix C1 to subpart R.
    (5) ANSI/ASHRAE Standard 41.3-2014 (``ANSI/ASHRAE 41.3''), Standard 
Methods for Pressure Measurement, ANSI-approved July 3, 2014; IBR 
approved for appendix C1 to subpart R.
    (6) ANSI/ASHRAE Standard 41.6-2014 (``ANSI/ASHRAE 41.6''), Standard 
Method for Humidity Measurement, ANSI-approved July 3, 2014; IBR 
approved for appendix C1 to subpart R.
    (7) ANSI/ASHRAE Standard 41.10-2013 (``ANSI/ASHRAE 41.10''), 
Standard Methods for Refrigerant Mass Flow Measurement Using 
Flowmeters, ANSI-approved June 27, 2013; IBR approved for appendix C1 
to subpart R.
    (d) ASTM. ASTM, International, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959; (610) 832-9500; www.astm.org.
    (1) ASTM C518-17, Standard Test Method for Steady-State Thermal 
Transmission Properties by Means of the Heat Flow Meter Apparatus, 
approved May 1, 2017; IBR approved for appendix B to subpart R.
    (2) ASTM C1199-14, Standard Test Method for Measuring the Steady-
State Thermal Transmittance of Fenestration Systems Using Hot Box 
Methods, approved February 1, 2014; IBR approved for appendix A to 
subpart R.
    (e) NFRC. National Fenestration Rating Council, 6305 Ivy Lane, Ste. 
140, Greenbelt, MD 20770; (301) 589-1776; www.nfrc.org/.
    (1) NFRC 102-2020 [E0A0] (``NFRC 102-2020''), Procedure for 
Measuring the Steady-State Thermal Transmittance of Fenestration 
Systems, copyright 2013; IBR approved for appendix A to subpart R.
    (2) [Reserved]

0
9. Amend Sec.  431.304 by revising paragraph (b) to read as follows:


Sec.  431.304  Uniform test method for the measurement of energy 
consumption of walk-in coolers and walk-in freezers.

* * * * *
    (b) Testing and calculations. Determine the energy efficiency and/
or energy consumption of the specified walk-in cooler and walk-in 
freezer components by conducting the appropriate test procedure as 
follows:
    (1) Display panels. Determine the energy use of walk-in cooler and 
walk-in freezer display panels by conducting the test procedure set 
forth in appendix A to this subpart.
    (2) Display doors and non-display doors. Determine the energy use 
of walk-in cooler and walk-in freezer display doors and non-display 
doors by conducting the test procedure set forth in appendix A to this 
subpart.
    (3) Non-display panels and non-display doors. Determine the R-value 
of insulation of walk-in cooler and walk-in freezer non-display panels 
and non-display doors by conducting the test procedure set forth in 
appendix B to this subpart.
    (4) Refrigeration systems. Determine the AWEF and net capacity of 
walk-in cooler and walk-in freezer refrigeration systems by conducting 
the test procedures set forth in appendix C or C1 to this subpart, as 
applicable. Refer to the notes at the beginning of those appendices to 
determine the applicable appendix to use for testing.
    (i) For unit coolers: follow the general testing provisions in 
sections 3.1 and 3.2, and the equipment-specific provisions in section 
3.3 of appendix C or sections 4.5 through 4.8 of appendix C1.
    (ii) For dedicated condensing units: follow the general testing 
provisions in sections 3.1 and 3.2, and the product-specific provisions 
in section 3.4 of appendix C or sections 4.5 through 4.8 of appendix 
C1.
    (iii) For single-packaged dedicated systems: follow the general 
testing provisions in sections 3.1 and 3.2, and the product-specific 
provisions in section 3.3 of appendix C or sections 4.5 through 4.8 of 
appendix C1.

0
10. Revise appendix A to subpart R of part 431 to read as follows:

Appendix A to Subpart R of Part 431--Uniform Test Method for the 
Measurement of Energy Consumption of the Components of Envelopes of 
Walk-In Coolers and Walk-In Freezers

    Note: Prior to October 31, 2023, representations with respect to 
the energy use of envelope components of walk-in coolers and walk-in 
freezers, including compliance certifications, must be based on 
testing conducted in accordance with the applicable provisions of 10 
CFR part 431, subpart R, appendix A, revised as of January 1, 2022. 
Beginning October 31, 2023, representations with respect to energy 
use of envelope components of walk-in coolers and walk-in freezers, 
including compliance certifications, must be based on testing 
conducted in accordance with this appendix.

0. Incorporation by Reference

    DOE incorporated by reference in Sec.  431.303 the entire 
standard for ASTM C1199-14 and NFRC 102-2020. However, certain 
enumerated provisions of these standards, as set forth in sections 
0.1 and 0.2 of this appendix are inapplicable. To the extent that 
there is a conflict between the terms or provisions of a referenced 
industry standard and the CFR, the CFR provisions control.

0.1 ASTM C1199-14

    (a) Section 1 Scope, is inapplicable,
    (b) Section 4 Significance and Use is inapplicable,
    (c) Section 7.3 Test Conditions, is inapplicable,
    (d) Section 10 Report, is inapplicable, and
    (e) Section 11 Precision and Bias, is inapplicable.

0.2 NFRC 102-2020

    (a) Section 1 Scope, is inapplicable,
    (b) Section 4 Significance and Use, is inapplicable,
    (c) Section 7.3 Test Conditions, is inapplicable,
    (d) Section 10 Report, is inapplicable,
    (e) Section 11 Precision and Bias, is inapplicable,
    (f) Annex A3 Standard Test Method for Determining the Thermal 
Transmittance of Tubular Daylighting Devices, is inapplicable, and
    (g) Annex A5 Tables and Figures, is inapplicable.
    1. General. The following sections of this appendix provide 
additional instructions for testing. In cases where there is a 
conflict, the language of this appendix takes highest precedence, 
followed by NFRC 102-2020, followed by ASTM C1199-14. Any subsequent 
amendment to a referenced

[[Page 28840]]

document by the standard-setting organization will not affect the 
test procedure in this appendix, unless and until the test procedure 
is amended by DOE. Material is incorporated as it exists on the date 
of the approval, and a notification of any change in the 
incorporation will be published in the Federal Register.

2. Scope

    This appendix covers the test requirements used to measure the 
energy consumption of the components that make up the envelope of a 
walk-in cooler or walk-in freezer.

3. Definitions

    The definitions contained in Sec.  431.302 are applicable to 
this appendix.

4. Additional Definitions

    4.1 Automatic door opener/closer means a device or control 
system that ``automatically'' opens and closes doors without direct 
user contact, such as a motion sensor that senses when a forklift is 
approaching the entrance to a door and opens it, and then closes the 
door after the forklift has passed.
    4.2 Percent time off (PTO) means the percent of time that an 
electrical device is assumed to be off.4.3 Rated power means the 
input power of an electricity-consuming device as specified on the 
device's nameplate. If the device does not have a nameplate or such 
nameplate does not list the device's input power, then the rated 
power must be determined from the device's product data sheet, 
literature, or installation instructions that come with the device 
or are available online.
    4.4 Rating conditions means, unless explicitly stated otherwise, 
all conditions shown in table A.1 of this appendix.

                    Table A.1--Temperature Conditions
------------------------------------------------------------------------
 
------------------------------------------------------------------------
        Internal Temperatures (cooled space within the envelope)
------------------------------------------------------------------------
Cooler Dry-Bulb Temperature................................    35 [deg]F
Freezer Dry-Bulb Temperature...............................   -10 [deg]F
------------------------------------------------------------------------
         External Temperatures (space external to the envelope)
------------------------------------------------------------------------
Freezer and Cooler Dry-Bulb Temperatures...................    75 [deg]F
------------------------------------------------------------------------

5. Test Methods and Measurements

5.1 U-Factor Test of Doors and Display Panels

    Determine the U-factor of the entire door or display panel, 
including the frame, in accordance with the specified sections of 
NFRC 102-2020 and ASTM C1199-14 at the temperature conditions listed 
in table A.1 of this appendix.

5.2 Required Test Measurements

    2.1 For display doors and display panels, thermal transmittance, 
Udd or Udp, respectively, shall be the 
standardized thermal transmittance, UST, determined per 
section 5.1.1 of this appendix.
    5.2.2 For non-display doors, thermal transmittance, 
Und, shall be the standardized thermal transmittance, 
UST, determined per section 5.1 of this appendix.
    5.2.3 Projected area of the test specimen, As, in ft\2\, as 
referenced in ASTM C1199-14.

6. Calculations

6.1 Display Panels

    6.1.1 Determine the U-factor of the display panel in accordance 
with section 5.1 of this appendix, in units of Btu/(h-ft\2\-[deg]F).
    6.1.2 Calculate the temperature differential, 
[Delta]Tdp, [deg]F, for the display panel, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.004

Where:

TDB,ext,dp = dry-bulb air external temperature, [deg]F, 
as prescribed in table A.1 of this appendix; and
TDB,int,dp = dry-bulb air temperature internal to the 
cooler or freezer, [deg]F, as prescribed in table A.1 of this 
appendix.

    6.1.3 Calculate the conduction load through the display panel, 
Qcond-dp, Btu/h, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.005

Where:

As = projected area of the test specimen (same as the 
test specimen aperture in the surround panel) or the area used to 
determine the U-factor in section 5.1 of this appendix, ft\2\;
[Delta]Tdp = temperature differential between 
refrigerated and adjacent zones, [deg]F; and
Udp = thermal transmittance, U-factor, of the display 
panel in accordance with section 5.1 of this appendix, Btu/(h-ft\2\-
[deg]F).

    6.1.4 Calculate the total daily energy consumption, 
Edp, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.006

Where:

Qcond,dp = the conduction load through the display panel, 
Btu/h; and
EER = Energy Efficiency Ratio of walk-in (cooler or freezer), Btu/W-
h. For coolers, use EER = 12.4 Btu/W-h. For freezers, use EER = 6.3 
Btu/W-h.

6.2 Display Doors

6.2.1 Conduction Through Display Doors

    6.2.1.1 Determine the U-factor of the display door in accordance 
with section 5.1 of this appendix, in units of Btu/(h-ft\2\-[deg]F).
    6.2.1.2 Calculate the temperature differential, 
[Delta]Tdd, [deg]F, for the display door as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.007

Where:

TDB,ext,dd = dry-bulb air temperature external to the 
display door, [deg]F, as prescribed in table A.1 of this appendix; 
and
TDB,int,dd = dry-bulb air temperature internal to the 
display door, [deg]F, as prescribed in table A.1 of this appendix.

    6.2.1.3 Calculate the conduction load through the display doors, 
Qcond,dd, Btu/h, as follows:

[[Page 28841]]

[GRAPHIC] [TIFF OMITTED] TR04MY23.008

Where:

As = projected area of the test specimen (same as the 
test specimen aperture in the surround panel) or the area used to 
determine the U-factor in section 5.1 of this appendix, ft\2\;
[Delta]Tdd = temperature differential between 
refrigerated and adjacent zones, [deg]F; and
Udd = thermal transmittance, U-factor of the door, in 
accordance with section 5.1 of this appendix, Btu/(h-ft\2\-[deg]F).

    6.2.1.4 Calculate the total daily energy consumption due to 
conduction thermal load, Edd,thermal, kWh/day, as 
follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.009

Where:

Qcond,dd = the conduction load through the display door, 
Btu/h; and
EER = EER of walk-in (cooler or freezer), Btu/W-h. For coolers, use 
EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).

6.2.2 Direct Energy Consumption of Electrical Component(s) of Display 
Doors

    Electrical components associated with display doors could 
include but are not limited to: heater wire (for anti-sweat or anti-
freeze application); lights; door motors; control system units; and 
sensors.
    6.2.2.1 Select the required value for percent time off (PTO) for 
each type of electricity-consuming device per table A.2 of this 
appendix, PTOt (%).

                                       Table A.2--Percent Time Off Values
----------------------------------------------------------------------------------------------------------------
                                                                       Controls, timer, or other   Percent time
                 Device                      Temperature condition       auto-shut-off system      off value (%)
----------------------------------------------------------------------------------------------------------------
Lights..................................  All.......................  Without...................              25
                                                                      With......................              50
Anti-sweat heaters......................  All.......................  Without...................               0
                                          Coolers...................  With......................              75
                                          Freezers..................  With......................              50
Door motors.............................  All.......................  ..........................              97
All other electricity-consuming devices.  All.......................  Without...................               0
                                                                      With......................              25
----------------------------------------------------------------------------------------------------------------

    6.2.2.2 Calculate the power usage for each type of electricity-
consuming device, Pdd,comp,u,t, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.010

Where:

u = the index for each of type of electricity-consuming device 
located on either (1) the interior facing side of the display door 
or within the inside portion of the display door, (2) the exterior 
facing side of the display door, or (3) any combination of (1) and 
(2). For purposes of this calculation, the interior index is 
represented by u = int and the exterior index is represented by u = 
ext. If the electrical component is both on the interior and 
exterior side of the display door then use u = int. For anti-sweat 
heaters sited anywhere in the display door, 75 percent of the total 
power is be attributed to u = int and 25 percent of the total power 
is attributed to u = ext;
t = index for each type of electricity-consuming device with 
identical rated power;
Prated,u,t = rated input power of each component, of type 
t, kW;
PTOu,t = percent time off, for device of type t, %; and
nu,t = number of devices at the rated input power of type 
t, unitless. 6.2.2.3 Calculate the total electrical energy 
consumption for interior and exterior power, Pdd,tot,int 
(kWh/day) and Pdd,tot,ext (kWh/day), respectively, as 
follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.011

[GRAPHIC] [TIFF OMITTED] TR04MY23.012

Where:

t = index for each type of electricity-consuming device with 
identical rated input power;
Pdd,comp,int,t = the energy usage for an electricity-
consuming device sited on the interior facing side of or in the 
display door, of type t, kWh/day; and
Pdd,comp,ext,t = the energy usage for an electricity-
consuming device sited on the external facing side of the display 
door, of type t, kWh/day. 6.2.2.4 Calculate the total electrical 
energy consumption, Pdd,tot, (kWh/day), as follows:

[[Page 28842]]

[GRAPHIC] [TIFF OMITTED] TR04MY23.013

Where:

Pdd,tot,int = the total interior electrical energy usage 
for the display door, kWh/day; and
Pdd,tot,ext = the total exterior electrical energy usage 
for the display door, kWh/day.

6.2.3 Total Indirect Electricity Consumption Due to Electrical Devices

    Calculate the additional refrigeration energy consumption due to 
thermal output from electrical components sited inside the display 
door, Cdd,load, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.014

Where:

Pdd,tot,int = The total internal electrical energy 
consumption due for the display door, kWh/day; and
EER = EER of walk-in cooler or walk-in freezer, Btu/W-h. For 
coolers, use EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/
(W-h).

6.2.4 Total Display Door Energy Consumption

    Calculate the total energy, Edd,tot, kWh/day,
    [GRAPHIC] [TIFF OMITTED] TR04MY23.015
    
Where:

Edd,thermal = the total daily energy consumption due to 
thermal load for the display door, kWh/day;
Pdd,tot = the total electrical load, kWh/day; and
Cdd,load = additional refrigeration load due to thermal 
output from electrical components contained within the display door, 
kWh/day.

6.3 Non-Display Doors

6.3.1 Conduction Through Non-Display Doors

    6.3.1.1 Determine the U-factor of the non-display door in 
accordance with section 5.1 of this appendix, in units of Btu/(h-
ft\2\-[deg]F).
    6.3.1.2 Calculate the temperature differential of the non-
display door, [Delta]Tnd, [deg]F, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.016

Where:

TDB,ext,nd = dry-bulb air external temperature, [deg]F, 
as prescribed by table A.1 of this appendix; and
TDB,int,nd = dry-bulb air internal temperature, [deg]F, 
as prescribed by table A.1 of this appendix. If the component spans 
both cooler and freezer spaces, the freezer temperature must be 
used.

    6.3.1.3 Calculate the conduction load through the non-display 
door: Qcond,nd, Btu/h,
[GRAPHIC] [TIFF OMITTED] TR04MY23.017

Where:

As = projected area of the test specimen (same as the 
test specimen aperture in the surround panel) or the area used to 
determine the U-factor in section 5.1 of this appendix, ft\2\;
[Delta]Tnd = temperature differential across the non-
display door, [deg]F; and
Und = thermal transmittance, U-factor of the door, in 
accordance with section 5.1 of this appendix, Btu/(h-ft\2\-[deg]F).

    6.3.1.4 Calculate the total daily energy consumption due to 
thermal load, End,thermal, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.018

Where:

Qcond,nd = the conduction load through the non-display 
door, Btu/h; and
EER = EER of walk-in (cooler or freezer), Btu/W-h. For coolers, use 
EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).

6.3.2 Direct Energy Consumption of Electrical Components of Non-Display 
Doors

    Electrical components associated with non-display doors comprise 
could include, but are not limited to: heater wire (for anti-sweat 
or anti-freeze application), lights, door motors, control system 
units, and sensors.
    6.3.2.1 Select the required value for percent time off for each 
type of electricity-consuming device per table A.2 of this appendix, 
PTOt (%).
    6.3.2.2 Calculate the power usage for each type of electricity-
consuming device, Pnd,comp,u,t, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.019


[[Page 28843]]


Where:

u = the index for each of type of electricity-consuming device 
located on either (1) the interior facing side of the non-display 
door or within the inside portion of the non-display door, (2) the 
exterior facing side of the non-display door, or (3) any combination 
of (1) and (2). For purposes of this calculation, the interior index 
is represented by u = int and the exterior index is represented by u 
= ext. If the electrical component is both on the interior and 
exterior side of the non-display door then use u = int. For anti-
sweat heaters sited anywhere in the non-display door, 75 percent of 
the total power is be attributed to u = int and 25 percent of the 
total power is attributed to u = ext;
t = index for each type of electricity-consuming device with 
identical rated input power;
Prated,u,t = rated input power of each component, of type 
t, kW;
PTOu,t = percent time off, for device of type t, %; and
nu,t = number of devices at the rated input power of type 
t, unitless.

    6.3.2.3 Calculate the total electrical energy consumption for 
interior and exterior power, Pnd,tot,int, kWh/day, and 
Pnd,tot,ext, kWh/day, respectively, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.020

[GRAPHIC] [TIFF OMITTED] TR04MY23.021

Where:

t = index for each type of electricity-consuming device with 
identical rated input power;
Pnd,comp,int,t = the energy usage for an electricity-
consuming device sited on the internal facing side or internal to 
the non-display door, of type t, kWh/day; and
Pnd,comp,ext,t = the energy usage for an electricity-
consuming device sited on the external facing side of the non-
display door, of type t, kWh/day. For anti-sweat heaters,

    6.3.2.4 Calculate the total electrical energy consumption, 
Pnd,tot, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.022

Where:

Pnd,tot,int = the total interior electrical energy usage 
for the non-display door, of type t, kWh/day; and
Pnd,tot,ext = the total exterior electrical energy usage 
for the non-display door, of type t, kWh/day.

6.3.3 Total Indirect Electricity Consumption Due to Electrical Devices

    Calculate the additional refrigeration energy consumption due to 
thermal output from electrical components associated with the non-
display door, Cnd,load, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.023

Where:

Pnd,tot,int = the total interior electrical energy 
consumption for the non-display door, kWh/day; and
EER = EER of walk-in cooler or freezer, Btu/W-h. For coolers, use 
EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).

6.3.4 Total Non-Display Door Energy Consumption

    Calculate the total energy, End,tot, kWh/day, as 
follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.024

Where:

End,thermal = the total daily energy consumption due to 
thermal load for the non-display door, kWh/day;
Pnd,tot = the total electrical energy consumption, kWh/
day; and
Cnd,load = additional refrigeration load due to thermal 
output from electrical components contained on the inside face of 
the non-display door, kWh/day.

0
11. Revise appendix B to subpart R of part 431 to read as follows:

Appendix B to Subpart R of Part 431--Uniform Test Method for the 
Measurement of R-Value of Insulation for Envelope Components of Walk-In 
Coolers and Walk-In Freezers

    Note:  Prior to October 31, 2023, representations with respect 
to the R-value for insulation of envelope components of walk-in 
coolers and walk-in freezers, including compliance certifications, 
must be based on testing conducted in accordance with the applicable 
provisions of 10 CFR part 431, subpart R, appendix B, revised as of 
January 1, 2022. Beginning October 31, 2023, representations with 
respect to R-value for insulation of envelope components of walk-in 
coolers and walk-in freezers, including compliance certifications, 
must be based on testing conducted in accordance with this appendix.

0. Incorporation by Reference

    DOE incorporated by reference in Sec.  431.303 the entire 
standard for ASTM C518-17. However, certain enumerated provisions of 
ASTM C518-17, as set forth in paragraph 0.1 of this appendix, are 
inapplicable. To the extent there is a conflict between the terms or 
provisions of a referenced industry standard and the CFR, the CFR 
provisions control.

0.1 ASTM C518-17

    (a) Section 1 Scope, is inapplicable,
    (b) Section 4 Significance and Use, is inapplicable,
    (c) Section 7.3 Specimen Conditioning, is inapplicable,
    (d) Section 9 Report, is inapplicable,
    (e) Section 10 Precision and Bias, is inapplicable,
    (f) Section 11 Keywords, is inapplicable,

[[Page 28844]]

    (g) Annex A2 Equipment Error Analysis, is inapplicable,
    (h) Appendix X1 is inapplicable,
    (i) Appendix X2 Response of Heat Flux Transducers, is 
inapplicable, and
    (j) Appendix X3 Proven Performance of a Heat Flow Apparatus, is 
inapplicable.

0.2 [Reserved]

1. General

    The following sections of this appendix provide additional 
instructions for testing. In cases where there is a conflict, the 
language of this appendix takes highest precedence, followed by ASTM 
C518-17. Any subsequent amendment to a referenced document by the 
standard-setting organization will not affect the test procedure in 
this appendix, unless and until the test procedure is amended by 
DOE. Material is incorporated as it exists on the date of the 
approval, and a notification of any change in the incorporation will 
be published in the Federal Register.

2. Scope

    This appendix covers the test requirements used to measure the 
R-value of non-display panels and non-display doors of a walk-in 
cooler or walk-in freezer.

3. Definitions

    The definitions contained in Sec.  431.302 apply to this 
appendix.

4. Additional Definitions

    4.1 Edge region means a region of the envelope component that is 
wide enough to encompass any framing members. If the envelope 
component contains framing members (e.g., a wood frame) then the 
width of the edge region must be as wide as any framing member plus 
an additional 2 in.  0.25 in.

5. Test Methods, Measurements, and Calculations

    5.1 General. Foam shall be tested after it is produced in its 
final chemical form. For foam produced inside of an envelope 
component (``foam-in-place''), ``final chemical form'' means the 
foam is cured as intended and ready for use as a finished envelope 
component. For foam produced as board stock (e.g., polystyrene), 
``final chemical form'' means after extrusion and ready for assembly 
into an envelope component or after assembly into an envelope 
component. Foam must not include any structural members or non-foam 
materials during testing in accordance with ASTM C518-17. When 
preparing the specimen for test, a high-speed bandsaw or a meat 
slicer are two types of recommended cutting tools. Hot wire cutters 
or other heated tools shall not be used for cutting foam test 
specimens.

5.2 Specimen Preparation

    5.2.1 Determining the thickness around the perimeter of the 
envelope component, tp. The full thickness of an envelope component 
around the perimeter, which may include facers on one or both sides, 
shall be determined as follows:
    5.2.1.1 At least 8 thickness measurements shall be taken around 
the perimeter of the envelope component, at least 2 inches from the 
edge region, and avoiding any regions with hardware or fixtures.
    5.2.1.2 The average of the thickness measurements taken around 
the perimeter of the envelope component shall be the thickness 
around the perimeter of the envelope component, tp.
    5.2.1.3 Measure and record the width, wp, and height, hp, of the 
envelope component. The surface area of the envelope component, Ap, 
shall be determined as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.025

Where:

wp = width of the envelope component, in.; and
hp = height of the envelope component, in.

    5.2.2. Removing the sample from the envelope component.
    5.2.2.1. Determine the center of the envelope component relative 
to its height and its width.
    5.2.2.2. Cut a sample from the envelope component that is at 
least the length and width dimensions of the heat flow meter, and 
where the marked center of the sample is at least 3 inches from any 
cut edge.
    5.2.2.3. If the center of the envelope component contains any 
non-foam components (excluding facers), additional samples may be 
cut adjacent to the previous cut that is at least the length and 
width dimensions of the heat flow meter and is greater than 12 
inches from the edge region.
    5.2.3. Determining the thickness at the center of the envelope 
component, tc. The full thickness of an envelope component at the 
center, which may include facers on one or both sides, shall be 
determined as follows:
    5.2.3.1. At least 2 thickness measurements shall be taken in 
each quadrant of the cut sample removed from the envelope component 
per section 5.2.2 of this appendix, for a total of at least 8 
measurements.
    5.2.3.2. The average of the thickness measurements of the cut 
sample removed from the envelope component shall be the overall 
thickness of the cut sample, tc.
    5.2.3.3. Measure and record the width and height of the cut 
sample removed from the envelope component. The surface area of the 
cut sample removed from the envelope component, Ac., shall be 
determined as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.026

Where:

wc = width of the cut sample removed from the envelope component, 
in.; and
hc = height of the cut sample removed from the envelope component, 
in.
    5.2.4. Determining the total thickness of the foam within the 
envelope component, tfoam. The average total thickness of the foam 
sample, without facers, shall be determined as follows:
    5.2.4.1. Remove the facers on the envelope component sample, 
while minimally disturbing the foam.
    5.2.4.2. Measure the thickness of each facer in 4 locations for 
a total of 4 measurements if 1 facer is removed, and a total of 8 
measurements if 2 facers are removed. The average of all facer 
measurements shall be the thickness of the facers, tfacers, in.
    5.2.4.3. The average total thickness of the foam, tfoam, in., 
shall be determined as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.027

Where:

tc = the average thickness of the center of the envelope component, 
in., as determined per sections 5.2.3.1 and 5.2.3.2 of this 
appendix;
Ac = the surface area of the center of the envelope component, 
in\2\., as determined per section 5.2.3.3 of this appendix;
tp = the average thickness of the perimeter of the envelope 
component, in., as determined per sections 5.2.1.1 and 5.2.1.2 of 
this appendix;
Ap = the average thickness of the center of the envelope component, 
in\2\, as determined per section 5.2.1.3 of this appendix;
tfacers = the average thickness of the facers of the envelope 
component, in., as determined per section 5.2.4.2 of this appendix.


[[Page 28845]]


    5.2.5. Cutting, measuring, and determining parallelism and 
flatness of a 1-inch-thick specimen for test from the center of the 
cut envelope component sample.
    5.2.5.1. Cut a 1  0.1-inch-thick specimen from the 
center of the cut envelope sample. The 1-inch-thick test specimen 
shall be cut from the point that is equidistant from both edges of 
the sample (i.e., shall be cut from the center point that would be 
directly between the interior and exterior space of the walk-in).
    5.2.5.2. Document through measurement or photographs with 
measurement indicators that the specimen was taken from the center 
of the sample.
    5.2.5.3 After the 1-inch specimen has been cut, and prior to 
testing, place the specimen on a flat surface and allow gravity to 
determine the specimen's position on the surface. This will be side 
1.
    5.2.5.4 To determine the flatness of side 1, take at least nine 
height measurements at equidistant positions on the specimen (i.e., 
the specimen would be divided into 9 regions and height measurements 
taken at the center of each of these nine regions). Contact with the 
measurement indicator shall not indent the foam surface. From the 
height measurements taken, determine the least squares plane for 
side 1. For each measurement location, calculate the theoretical 
height from the least squares plane for side 1. Then, calculate the 
difference between the measured height and the theoretical least 
squares plane height at each location. The maximum difference minus 
the minimum difference out of the nine measurement locations is the 
flatness of side 1. For side 1 of the specimen to be considered 
flat, this shall be less than or equal to 0.03 inches.
    5.2.5.5 To determine the flatness of side 2, turn the specimen 
over and allow gravity to determine the specimen's position on the 
surface. Repeat section 5.2.5.4 to determine the flatness of side 2.
    5.2.5.6 To determine the parallelism of the specimen for side 1, 
calculate the theoretical height of the least squares plane at the 
furthest corners (i.e., at points (0,0), (0,12), (12,0), and 
(12,12)) of the 12-inch by 12-inch test specimen. The difference 
between the maximum theoretical height and the minimum theoretical 
height shall be less than or equal to 0.03 inches for each side in 
order for side 1 to be considered parallel.
    5.2.5.7 To determine the parallelism of the specimen for side 2, 
repeat section
    5.2.5.8 The average thickness of the test specimen, L, shall be 
1  0.1-inches determined using a minimum of 18 thickness 
measurements (i.e., a minimum of 9 measurements on side 1 of the 
specimen and a minimum of 9 on side 2 of the specimen). This average 
thickness shall be used to determine the thermal conductivity, or K-
factor.
    5.3 K-factor Test. Determine the thermal conductivity, or K-
factor, of the 1-inch-thick specimen in accordance with the 
specified sections of ASTM C518-17.
    5.3.1 Test Conditions.
    5.3.1.1 For freezer envelope components, the K-factor of the 
specimen shall be determined at an average specimen temperature of 
20  1 degrees Fahrenheit.
    5.3.1.2 For cooler envelope components, the K-factor of the 
specimen shall be determined at an average specimen temperature of 
55  1 degrees Fahrenheit.
    5.4 R-value Calculation.
    5.4.1 For envelope components consisting of one homogeneous 
layer of insulation, calculate the R-value, h-ft\2\-[deg]F/Btu, as 
follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.028

Where:

tfoam = the total thickness of the foam, in., as determined in 
section 5.2.4 of this appendix; and
[lgr] = K-factor, Btu-in/(h-ft\2\-[deg]F), as determined in section 
5.3 of this appendix.
    5.4.2 For envelope components consisting of two or more layers 
of dissimilar insulating materials (excluding facers or protective 
skins), determine the K-factor of each material as described in 
sections 5.1 through 5.3 of this appendix. For an envelope component 
with N layers of insulating material, the overall R-value shall be 
calculated as follows:

[GRAPHIC] [TIFF OMITTED] TR04MY23.029

Where:

ti is the thickness of the ith material that appears in the envelope 
component, inches, as determined in section 5.2.4 of this appendix;
[lgr]i is the k-factor of the ith material, Btu-in/(h-
ft\2\-[deg]F), as determined in section 5.3 of this appendix; and
N is the total number of material layers that appears in the 
envelope component.

    5.4.3 K-factor test results from a test sample 1  
0.1-inches in thickness may be used to determine the R-value of 
envelope components with various foam thicknesses as long as the 
foam throughout the panel depth is of the same final chemical form 
and the test was completed at the same test conditions that the 
other envelope components would be used at. For example, a K-factor 
test result conducted at cooler conditions cannot be used to 
determine R-value of a freezer envelope component.

0
12. Amend appendix C to subpart R of part 431 by:
0
a. Adding an introductory note;
0
b. Revising sections 2.0 and 3.1.1;
0
c. Adding sections 3.1.6 and 3.1.7;
0
d. Revising sections 3.2.1 and 3.2.3;
0
e. Adding sections 3.2.6, 3.2.6.1, 3.2.6.1.1, 3.2.6.1.2, 3.2.6.2, 
3.2.6.3, 3.2.6.4, 3.2.7, 3.2.7.1, 3.2.7.2, and 3.2.8;
0
f. Revising sections 3.3.1 and 3.3.3;
0
g. Adding sections 3.3.3.1, 3.3.3.2, 3.3.3.3, 3.3.3.3.1, and 3.3.3.3.2;
0
h. Revising sections 3.3.7, 3.3.7.1, and 3.3.7.2;
0
i. Adding sections 3.3.7.3, 3.3.7.3.1, and 3.3.7.3.2; and
0
j. Revising section 3.4.2.1.
    The additions and revisions read as follows:

Appendix C to Subpart R of Part 431--Uniform Test Method for the 
Measurement of Net Capacity and AWEF of Walk-In Cooler and Walk-In 
Freezer Refrigeration Systems

    Note: Prior to October 31, 2023, representations with respect to 
the energy use of refrigeration components of walk-in coolers and 
walk-in freezers, including compliance certifications, must be based 
on testing conducted in accordance with the applicable provisions of 
10 CFR part 431, subpart R, appendix C, revised as of January 1, 
2022. Beginning October 31, 2023, representations with respect to 
energy use of refrigeration components of walk-in coolers and walk-
in freezers, including compliance certifications, must be based on 
testing conducted in accordance with this appendix.
    For any amended standards for walk-in coolers and freezers 
published after January 1, 2022, manufacturers must use the results 
of testing under appendix C1 to this subpart to determine 
compliance. Representations related to energy consumption must be 
made in accordance with appendix C1 when determining compliance with 
the relevant standard. Manufacturers may also use appendix C1 to 
certify compliance with any amended standards prior to the 
applicable compliance date for those standards.

* * * * *

2.0 Definitions

    The definitions contained in Sec.  431.302 and AHRI 1250-2009 
(incorporated by reference; see Sec.  431.303) apply to this 
appendix. When definitions contained in the standards DOE has 
incorporated by reference are in conflict or when they conflict with 
this section, the

[[Page 28846]]

hierarchy of precedence shall be in the following order: Sec.  
431.302, AHRI 1250-2009, and then either AHRI 420-2008 (incorporated 
by reference; see Sec.  431.303) for unit coolers or ASHRAE 23.1-
2010 (incorporated by reference; see Sec.  431.303) for dedicated 
condensing units.
    The term ``unit cooler'' used in AHRI 1250-2009, AHRI 420-2008, 
and this subpart shall be considered to address both ``unit 
coolers'' and ``ducted fan coil units,'' as appropriate.

3.0 * * *

3.1. * * *

    3.1.1. In Table 1, Instrumentation Accuracy, refrigerant 
temperature measurements shall have an accuracy of +/-0.5 [deg]F for 
unit cooler in/out. When testing high-temperature refrigeration 
systems, measurements used to determine temperature or water vapor 
content of the air (i.e., wet-bulb or dew point) shall be accurate 
to within +/-0.25 [deg]F; all other temperature measurements shall 
be accurate to within +/-1.0 [deg]F.
* * * * *

3.1.6. Test Operating Conditions for CO2 Unit Coolers

    For medium-temperature CO2 unit coolers, conduct 
tests using the test conditions specified in table 17 of this 
appendix. For low-temperature CO2 unit coolers, conduct 
tests using the test conditions specified in table 18 of this 
appendix.

                                       Table 17--Test Operating Conditions for Medium-Temperature CO2 Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Unit
                                         Unit       cooler
                                        cooler       air       Suction   Liquid inlet     Liquid
          Test description                air      entering  dew  point  bubble point      inlet         Compressor  capacity         Test objective
                                       entering    relative     temp,     temperature   subcooling,
                                       dry-bulb,  humidity,    [deg]F       [deg]F        [deg]F
                                        [deg]F        %
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power.....................          35        <50  ..........  ............  ............  Compressor On..............  Measure fan input
                                                                                                                                   power during
                                                                                                                                   compressor off-cycle.
Refrigeration Capacity, Ambient               35        <50          25            38             5  Compressor Off.............  Determine Net
 Condition A.                                                                                                                      Refrigeration
                                                                                                                                   Capacity of Unit
                                                                                                                                   Cooler.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1. Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.


                                        Table 18--Test Operating Conditions for Low-Temperature CO2 Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Unit
                                         Unit       cooler
                                        cooler       air       Suction   Liquid inlet     Liquid
          Test description                air      entering  dew  point  bubble point      inlet         Compressor  capacity         Test objective
                                       entering    relative     temp,     temperature   subcooling,
                                       dry-bulb,  humidity,    [deg]F       [deg]F        [deg]F
                                        [deg]F        %
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power.....................         -10        <50  ..........  ............  ............  Compressor Off.............  Measure fan input
                                                                                                                                   power during
                                                                                                                                   compressor off cycle.
Refrigeration Capacity, Ambient              -10        <50         -20            38             5  Compressor On..............  Determine Net
 Condition A.                                                                                                                      Refrigeration
                                                                                                                                   Capacity of Unit
                                                                                                                                   Cooler.
Defrost.............................         -10        <50  ..........  ............  ............  Compressor Off.............  Test according to
                                                                                                                                   Appendix C Section
                                                                                                                                   C11 of AHRI 1250-
                                                                                                                                   2009.
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.

3.1.7. Test Operating Conditions for High-Temperature Unit Coolers

    For high-temperature cooler unit coolers, conduct tests using 
the test conditions specified in table 19 of this appendix.

                                          Table 19--Test Operating Conditions for High-Temperature Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Unit
                                         Unit       cooler     Suction
                                        cooler       air     dew  point  Liquid inlet     Liquid
          Test description                air      entering     temp,    bubble point      inlet         Compressor  capacity         Test objective
                                       entering    relative  [deg]F \2\   temperature   subcooling,
                                       dry-bulb,  humidity,      \3\        [deg]F        [deg]F
                                        [deg]F       % \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle...........................          55         55  ..........           105             9  Compressor Off.............  Measure fan input
                                                                                                                                   power.
Refrigeration Capacity Suction A....          55         55          38           105             9  Compressor On..............  Determine Net
                                                                                                                                   Refrigeration
                                                                                                                                   Capacity of Unit
                                                                                                                                   Cooler.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ The test condition tolerance (maximum permissible variation of the average value of the measurement from the specified test condition) for relative
  humidity is 3%.
\2\ Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.
\3\ Suction Dew Point shall be measured at the Unit Cooler Exit.

3.2. * * *

3.2.1. Refrigerant Temperature Measurements

    In AHRI 1250-2009 appendix C, section C3.1.6, any refrigerant 
temperature measurements entering and leaving the unit cooler may 
use sheathed sensors immersed in the flowing refrigerant instead of 
thermometer wells. When testing a condensing unit alone, measure 
refrigerant liquid temperature leaving the condensing unit using 
thermometer wells as described in AHRI 1250-2009 appendix C, section 
C3.1.6 or sheathed sensors immersed in the flowing refrigerant. For 
all of these cases, if the refrigerant tube outer diameter is less 
than \1/2\ inch, the refrigerant temperature may be measured using 
the average of two

[[Page 28847]]

temperature measuring instruments with a minimum accuracy of 0.5 [deg]F placed on opposite sides of the refrigerant tube 
surface--resulting in a total of up to 8 temperature measurement 
devices used for the DX Dual Instrumentation method. In this case, 
the refrigerant tube shall be insulated with 1-inch thick insulation 
from a point 6 inches upstream of the measurement location to a 
point 6 inches downstream of the measurement location. Also, to 
comply with this requirement, the unit cooler entering measurement 
location may be moved to a location 6 inches upstream of the 
expansion device and, when testing a condensing unit alone, the 
entering and leaving measurement locations may be moved to locations 
6 inches from the respective service valves.
* * * * *

3.2.3. Subcooling at Refrigerant Mass Flow Meter

    In appendix C, section C3.4.5 of AHRI 1250-2009 (incorporated by 
reference; see Sec.  431.303), and in section 7.1.2 of ASHRAE 23.1-
2010 (incorporated by reference; see Sec.  431.303) when verifying 
subcooling at the mass flow meters, only the sight glass and a 
temperature sensor located on the tube surface under the insulation 
are required. Subcooling shall be verified to be within the 3 [deg]F 
requirement downstream of flow meters located in the same chamber as 
a condensing unit under test and upstream of flow meters located in 
the same chamber as a unit cooler under test, rather than always 
downstream as indicated in AHRI 1250-2009, section C3.4.5 or always 
upstream as indicated in section 7.1.2 of ASHRAE 23.1-2010. If the 
subcooling is less than 3 [deg]F, cool the line between the 
condensing unit outlet and this location to achieve the required 
subcooling. When providing such cooling while testing a matched 
pair, (a) set up the line-cooling system and also set up apparatus 
to heat the liquid line between the mass flow meters and the unit 
cooler, (b) when the system has achieved steady state without 
activation of the heating and cooling systems, measure the liquid 
temperature entering the expansion valve for a period of at least 30 
minutes, (c) activate the cooling system to provide the required 
subcooling at the mass flow meters, (d) if necessary, apply heat 
such that the temperature entering the expansion valve is within 0.5 
\0\F of the temperature measured during step (b), and (e) proceed 
with measurements once condition (d) has been verified.
* * * * *

3.2.6. Installation Instructions

    Manufacturer installation instructions refer to the instructions 
that are applied to the unit (i.e., as a label) or that come 
packaged with the unit. Online installation instructions are 
acceptable only if the version number or date of publication is 
referenced on the unit label or in the documents that are packaged 
with the unit.
    3.2.6.1 Installation Instruction Hierarchy when available 
installation instructions are in conflict
    3.2.6.1.1 If a manufacturer installation instruction provided on 
the label(s) applied to the unit conflicts with the manufacturer 
installation instructions that are shipped with the unit, the 
instructions on the unit's label take precedence.
    3.2.6.1.2 Manufacturer installation instructions provided in any 
documents that are packaged with the unit take precedence over any 
manufacturer installation instructions provided online.
    3.2.6.2 For testing of attached split systems, the manufacturer 
installation instructions for the dedicated condensing unit shall 
take precedence over the manufacturer installation instructions for 
the unit cooler.
    3.2.6.3 Unit setup shall be in accordance with the manufacturer 
installation instructions (laboratory installation instructions 
shall not be used).
    3.2.6.4 Achieving test conditions shall always take precedence 
over installation instructions.
    3.2.7. Refrigerant Charging and Adjustment of Superheat and 
Subcooling.
    All dedicated condensing systems (dedicated condensing units 
tested alone, matched pairs, and single packaged dedicated systems) 
that use flooding of the condenser for head pressure control during 
low-ambient-temperature conditions shall be charged, and superheat 
and/or subcooling shall be set, at Refrigeration C test conditions 
unless otherwise specified in the installation instructions.
    If after being charged at Refrigeration C condition the unit 
under test does not operate at the Refrigeration A condition due to 
high pressure cut out, refrigerant shall be removed in increments of 
4 ounces or 5 percent of the test unit's receiver capacity, 
whichever quantity is larger, until the unit operates at the 
Refrigeration A condition. All tests shall be run at this final 
refrigerant charge. If less than 0 [deg]F of subcooling is measured 
for the refrigerant leaving the condensing unit when testing at B or 
C condition, calculate the refrigerant-enthalpy-based capacity 
(i.e., when using the DX dual instrumentation, the DX calibrated 
box, or single-packaged unit refrigerant enthalpy method) assuming 
that the refrigerant is at saturated liquid conditions at the 
condensing unit exit.
    All dedicated condensing systems that do not use a flooded 
condenser design shall be charged at Refrigeration A test conditions 
unless otherwise specified in the installation instructions.
    If the installation instructions give a specified range for 
superheat, sub-cooling, or refrigerant pressure, the average of the 
range shall be used as the refrigerant charging parameter target and 
the test condition tolerance shall be 50 percent of the 
range. Perform charging of near-azeotropic and zeotropic 
refrigerants only with refrigerant in the liquid state. Once the 
correct refrigerant charge is determined, all tests shall run until 
completion without further modification.
    3.2.7.1. When charging or adjusting superheat/subcooling, use 
all pertinent instructions contained in the installation 
instructions to achieve charging parameters within the tolerances. 
However, in the event of conflicting charging information between 
installation instructions, follow the installation instruction 
hierarchy listed in section 3.2.6. of this appendix. Conflicting 
information is defined as multiple conditions given for charge 
adjustment where all conditions specified cannot be met. In the 
event of conflicting information within the same set of charging 
instructions (e.g., the installation instructions shipped with the 
dedicated condensing unit), follow the hierarchy in table 1 of this 
section for priority. Unless the installation instructions specify a 
different charging tolerance, the tolerances identified in table 1 
of this section shall be used.

 Table 1--Test Condition Tolerances and Hierarchy for Refrigerant Charging and Setting of Refrigerant Conditions
----------------------------------------------------------------------------------------------------------------
                                   Fixed orifice                                  Expansion valve
                 -----------------------------------------------------------------------------------------------
    Priority          Parameter with                                  Parameter with
                       installation              Tolerance             installation              Tolerance
                    instruction target                              instruction target
----------------------------------------------------------------------------------------------------------------
1...............  Superheat.............  2.0 [deg]F  Subcooling............  10% of the Target
                                                                                           Value; No less than
                                                                                           0.5
                                                                                           [deg]F, No more than
                                                                                           2.0
                                                                                           [deg]F.
2...............  High Side Pressure or   4.0 psi or  High Side Pressure or   4.0 psi or
                   Saturation              1.0         Saturation              1.0
                   Temperature.            [deg]F.                 Temperature.            [deg]F.
3...............  Low Side Pressure or    2.0 psi or  Superheat.............  2.0
                   Saturation              0.8                                 [deg]F.
                   Temperature.            [deg]F.
4...............  Low Side Temperature..  2.0 [deg]F  Low Side Pressure or    2.0 psi or
                                                                   Saturation              0.8
                                                                   Temperature.            [deg]F.
5...............  High Side Temperature.  2.0 [deg]F  Approach Temperature..  1.0
                                                                                           [deg]F.

[[Page 28848]]

 
6...............  Charge Weight.........  2.0 oz....  Charge Weight.........  0.5% or 1.0 oz,
                                                                                           whichever is greater.
----------------------------------------------------------------------------------------------------------------

    3.2.7.2. Dedicated Condensing Unit. If the Dedicated Condensing 
Unit includes a receiver and the subcooling target leaving the 
condensing unit provided in installation instructions cannot be met 
without fully filling the receiver, the subcooling target shall be 
ignored. Likewise, if the Dedicated Condensing unit does not include 
a receiver and the subcooling target leaving the condensing unit 
cannot be met without the unit cycling off on high pressure, the 
subcooling target can be ignored. Also, if no instructions for 
charging or for setting subcooling leaving the condensing unit are 
provided in the installation instructions, the refrigeration system 
shall be set up with a charge quantity and/or exit subcooling such 
that the unit operates during testing without shutdown (e.g., on a 
high-pressure switch) and operation of the unit is otherwise 
consistent with the requirements of the test procedure of this 
appendix and the installation instructions.
    3.2.8. Chamber Conditioning using the Unit Under Test.
    In appendix C, section C6.2 of AHRI 1250-2009, for applicable 
system configurations (matched pairs, single-packaged refrigeration 
systems, and standalone unit coolers), the unit under test may be 
used to aid in achieving the required test chamber conditions prior 
to beginning any steady state test. However, the unit under test 
must be inspected and confirmed to be free from frost before 
initiating steady state testing.
* * * * *
    3.3. * * *
    3.3.1. For unit coolers tested alone, use test procedures 
described in AHRI 1250-2009 for testing unit coolers for use in mix-
match system ratings, except that for the test conditions in tables 
15 and 16 of this appendix, use the Suction A saturation condition 
test points only. Also, for unit coolers tested alone, other than 
high-temperature unit coolers, use the calculations in section 7.9 
of AHRI 1250-2009 to determine AWEF and net capacity described in 
AHRI 1250-2009 for unit coolers matched to parallel rack systems.
* * * * *
    3.3.3. Evaporator Fan Power.
    3.3.3.1. Ducted Evaporator Air.
    For ducted fan coil units with ducted evaporator air, or that 
can be installed with or without ducted evaporator air: Connect 
ductwork on both the inlet and outlet connections and determine 
external static pressure as described in ASHRAE 37 (incorporated by 
reference; see Sec.  431.303), sections 6.4 and 6.5. Use pressure 
measurement instrumentation as described in ASHRAE 37, section 
5.3.2. Test at the fan speed specified in manufacturer installation 
instructions--if there is more than one fan speed setting and the 
installation instructions do not specify which speed to use, test at 
the highest speed. Conduct tests with the external static pressure 
equal to 50 percent of the maximum external static pressure allowed 
by the manufacturer for system installation within a tolerance of -
0.00/+0.05 in. wc. Set the external static pressure by symmetrically 
restricting the outlet of the test duct. Alternatively, if using the 
indoor air enthalpy method to measure capacity, set external static 
pressure by adjusting the fan of the airflow measurement apparatus. 
In case of conflict, these requirements for setting evaporator 
airflow take precedence over airflow values specified in 
manufacturer installation instructions or product literature.
    3.3.3.2. Unit Coolers or Single-Packaged Systems that are not 
High-Temperature Refrigeration Systems.
    Use appendix C, section C10 of AHRI 1250-2009 for off-cycle 
evaporator fan testing, with the exception that evaporator fan 
controls using periodic stir cycles shall be adjusted so that the 
greater of a 50 percent duty cycle (rather than a 25 percent duty 
cycle) or the manufacturer default is used for measuring off-cycle 
fan energy. For adjustable-speed controls, the greater of 50 percent 
fan speed (rather than 25 percent fan speed) or the manufacturer's 
default fan speed shall be used for measuring off-cycle fan energy. 
Also, a two-speed or multi-speed fan control may be used as the 
qualifying evaporator fan control. For such a control, a fan speed 
no less than 50 percent of the speed used in the maximum capacity 
tests shall be used for measuring off-cycle fan energy.
    3.3.3.3. High-Temperature Refrigeration Systems.
    3.3.3.3.1. The evaporator fan power consumption shall be 
measured in accordance with the requirements in section C3.5 of AHRI 
1250-2009. This measurement shall be made with the fan operating at 
full speed, either measuring unit cooler or total system power input 
upon the completion of the steady state test when the compressor and 
the condenser fan of the walk-in system are turned off, or by 
submetered measurement of the evaporator fan power during the steady 
state test.
    Section C3.5 of AHRI 1250-2009 is revised to read:
    Evaporator Fan Power Measurement.
    The following shall be measured and recorded during a fan power 
test.

EFcomp,on Total electrical power input to fan motor(s) of 
Unit Cooler, W
FS Fan speed(s), rpm
N Number of motors
Pb Barometric pressure, in. Hg
Tdb Dry-bulb temperature of air at inlet, [deg]F
Twb Wet-bulb temperature of air at inlet, [deg]F
V Voltage of each phase

    For a given motor winding configuration, the total power input 
shall be measured at the highest nameplate voltage. For three-phase 
power, voltage imbalance shall be no more than 2%.
    3.3.3.3.2. Evaporator fan power for the off-cycle is equal to 
the on-cycle evaporator fan power with a run time of 10 percent of 
the off-cycle time.

EFcomp,off = 0.1 x EFcomp,on

* * * * *
    3.3.7. Calculations for Unit Coolers Tested Alone.
    3.3.7.1. Unit Coolers that are not High-Temperature Unit 
Coolers.
    Calculate the AWEF and net capacity using the calculations in 
AHRI 1250-2009, section 7.9.
    3.3.7.2 High-Temperature Unit Coolers.
    Calculate AWEF on the basis that walk-in box load is equal to 
half of the system net capacity, without variation according to high 
and low load periods, and with EER set according to tested 
evaporator capacity, as follows:
    The net capacity, qmix,evap, is determined from the test data 
for the unit cooler at the 38 [deg]F suction dewpoint.

[[Page 28849]]

[GRAPHIC] [TIFF OMITTED] TR04MY23.030

Where:
[GRAPHIC] [TIFF OMITTED] TR04MY23.031


Where:

BL is the non-equipment-related box load;
LF is the load factor; and
Other symbols are as defined in section 8 of AHRI 1250-2009.

    3.3.7.3. If the unit cooler has variable-speed evaporator fans 
that vary fan speed in response to load, then:
    3.3.7.3.1. When testing to certify compliance with the energy 
conservation standards in Sec.  431.306, fans shall operate at full 
speed during on-cycle operation. Do not conduct the calculations in 
AHRI 1250-2009, section 7.9.3. Instead, use AHRI 1250-2009, section 
7.9.2 to determine the system's AWEF.
    3.3.7.3.2. When calculating the benefit for the inclusion of 
variable-speed evaporator fans that modulate fan speed in response 
to load for the purpose of making representations of efficiency, use 
AHRI 1250-2009, section 7.9.3 to determine the system AWEF.
    3.4. * * *
    3.4.2. * * *
    3.4.2.1. For calculating enthalpy leaving the unit cooler to 
calculate gross capacity, (a) the saturated refrigerant temperature 
(dew point) at the unit cooler coil exit, Tevap, shall be 
25 [deg]F for medium-temperature systems (coolers) and -20 [deg]F 
for low-temperature systems (freezers), and (b) the refrigerant 
temperature at the unit cooler exit shall be 35 [deg]F for medium-
temperature systems (coolers) and -14 [deg]F for low-temperature 
systems (freezers). For calculating gross capacity, the measured 
enthalpy at the condensing unit exit shall be used as the enthalpy 
entering the unit cooler. The temperature measurement requirements 
of appendix C, section C3.1.6 of AHRI 1250-2009 and modified by 
section 3.2.1 of this appendix shall apply only to the condensing 
unit exit rather than to the unit cooler inlet and outlet, and they 
shall be applied for two measurements when using the DX Dual 
Instrumentation test method.
* * * * *

0
13. Add appendix C1 to subpart R of part 431 to read as follows:

Appendix C1 to Subpart R of Part 431--Uniform Test Method for the 
Measurement of Net Capacity and AWEF2 of Walk-In Cooler and Walk-In 
Freezer Refrigeration Systems

    Note: Prior to October 31, 2023, representations with respect to 
the energy use of refrigeration components of walk-in coolers and 
walk-in freezers, including compliance certifications, must be based 
on testing conducted in accordance with the applicable provisions 
for 10 CFR part 431, subpart R, appendix C, revised as of January 1, 
2022. Beginning October 31, 2023, representations with respect to 
energy use of refrigeration components of walk-in coolers and walk-
in freezers, including compliance certifications, must be based on 
testing conducted in accordance with appendix C to this subpart.
    For any amended standards for walk-in coolers and walk-in 
freezers published after January 1, 2022, manufacturers must use the 
results of testing under this appendix to determine compliance. 
Representations related to energy consumption must be made in 
accordance with this appendix when determining compliance with the 
relevant standard. Manufacturers may also use this appendix to 
certify compliance with any amended standards prior to the 
applicable compliance date for those standards.

0. Incorporation by Reference

    DOE incorporated by reference in Sec.  431.303, the entire 
standard for AHRI 1250-2020, ANSI/ASHRAE 16, ANSI/ASHRAE 23.1-2010, 
ANSI/ASHRAE 37, ANSI/ASHRAE 41.1, ANSI/ASHRAE 41.3, ANSI/ASHRAE 
41.6, and ANSI/ASHRAE 41.10. However, certain enumerated provisions 
of these standards, as set forth in sections 0.1 through 0.8 of this 
appendix are inapplicable. To the extent there is a conflict between 
the terms or provisions of a referenced industry standard and the 
CFR, the CFR provisions control. To the extent there is a conflict 
between the terms or provisions of AHRI 1250-2020, ANSI/ASHRAE 16, 
ANSI/ASHRAE 23.1-2010, ANSI/ASHRAE 37, ANSI/ASHRAE 41.1, ANSI/ASHRAE 
41.3, ANSI/ASHRAE 41.6, and ANSI/ASHRAE 41.10, the AHRI 1250-2020 
provisions control.

0.1 AHRI 1250-2020

(a) Section 1 Purpose, is inapplicable
(b) Section 2 Scope, is inapplicable
(c) Section 9 Minimum Data Requirements for Published Rating, is 
inapplicable
(d) Section 10 Marking and Nameplate Data, is inapplicable

[[Page 28850]]

(e) Section 11 Conformance Conditions, is inapplicable

0.2 ANSI/ASHRAE 16

(a) Section 1 Purpose, is inapplicable
(b) Section 2 Scope, is inapplicable
(c) Section 4 Classifications, is inapplicable
(d) Normative Appendices E-M, are inapplicable
(e) Informative Appendices N-R, are inapplicable

0.3 ANSI/ASHRAE 23.1-2010

(a) Section 1 Purpose, is inapplicable
(b) Section 2 Scope, is inapplicable
(c) Section 4 Classifications, is inapplicable

0.4 ANSI/ASHRAE 37

(a) Section 1 Purpose, is inapplicable
(b) Section 2 Scope, is inapplicable
(c) Section 4 Classifications, is inapplicable
(d) Informative Appendix A Classifications of Unitary Air-
conditioners and Heat Pumps, is inapplicable.

0.5 ANSI/ASHRAE 41.1

(a) Section 1 Purpose, is inapplicable
(b) Section 2 Scope, is inapplicable
(c) Section 4 Classifications, is inapplicable
(d) Section 9 Test Report, is inapplicable
(e) Informative Appendices A-C, are inapplicable

0.6 ANSI/ASHRAE 41.3

(a) Section 1 Purpose, is inapplicable
(b) Section 2 Scope, is inapplicable
(c) Section 4 Classifications, is inapplicable
(d) Section 6 Instrument Types (informative), is inapplicable
(e) Section 8 Test Report, is inapplicable
(f) Informative Annexes A-D, are inapplicable

0.7 ANSI/ASHRAE 41.6

(a) Section 1 Purpose, is inapplicable
(b) Section 2 Scope, is inapplicable
(c) Section 4 Classifications, is inapplicable
(d) Section 9 Test Report, is inapplicable
(e) Informative Appendices A-D, are inapplicable

0.8 ANSI/ASHRAE 41.10

(a) Section 1 Purpose, is inapplicable
(b) Section 2 Scope, is inapplicable
(c) Section 4 Classifications, is inapplicable
(d) Section 10 Test Report, is inapplicable
(e) Informative Annexes A-D, are inapplicable

1. Scope

    This appendix covers the test requirements used to determine the 
net capacity and the AWEF2 of the refrigeration system of a walk-in 
cooler or walk-in freezer.

2. Definitions

2.1. Applicable Definitions

    The definitions contained in Sec.  431.302, AHRI 1250-2020, 
ANSI/ASHRAE 37, and ANSI/ASHRAE 16 apply to this appendix. When 
definitions in standards incorporated by reference are in conflict 
or when they conflict with this section, the hierarchy of precedence 
shall be in the following order: Sec.  431.302, AHRI 1250-2020, and 
then either ANSI/ASHRAE 37 or ANSI/ASHRAE 16.
    The term ``unit cooler'' used in AHRI 1250-2020 and this subpart 
shall be considered to address both ``unit coolers'' and ``ducted 
fan coil units,'' as appropriate.

2.2. Additional Definitions

    2.2.1. Digital Compressor means a compressor that uses 
mechanical means for disengaging active compression on a cyclic 
basis to provide a reduced average refrigerant flow rate in response 
to a control system input signal.
    2.2.2. Displacement Ratio, applicable to staged positive 
displacement compressor systems, means the swept volume rate, e.g. 
in cubic centimeters per second, of a given stage, divided by the 
swept volume rate at full capacity.
    2.2.3. Duty Cycle, applicable to digital compressors, means the 
fraction of time that the compressor is engaged and actively 
compressing refrigerant.
    2.2.4. Maximum Speed, applicable to variable-speed compressors, 
means the maximum speed at which the compressor will operate under 
the control of the dedicated condensing system control system for 
extended periods of time, i.e. not including short-duration boost-
mode operation.
    2.2.5. Minimum Speed, applicable to variable-speed compressors, 
means the minimum compressor speed at which the compressor will 
operate under the control of the dedicated condensing system control 
system.
    2.2.6. Multiple-Capacity, applicable for describing a 
refrigeration system, indicates that it has three or more stages 
(levels) of capacity.
    2.2.7. Speed Ratio, applicable to variable-speed compressors, 
means the ratio of operating speed to the maximum speed.

3. Test Methods, Measurements, and Calculations

    Determine the Annual Walk-in Energy Factor (AWEF2) and net 
capacity of walk-in cooler and walk-in freezer refrigeration systems 
by conducting the test procedure set forth in AHRI 1250-2020, with 
the modifications to that test procedure provided in this section. 
However, certain sections of AHRI 1250-2020, ANSI/ASHRAE 37, and 
ANSI/ASHRAE 16 are not applicable, as set forth in sections 0.1, 
0.2, and 0.3 of this appendix. Round AWEF2 measurements to the 
nearest 0.01 Btu/Wh. Round net capacity measurements as indicated in 
table 1 of this appendix.

         Table 1--Rounding of Refrigeration System Net Capacity
------------------------------------------------------------------------
                                                                Rounding
                  Net capacity range, Btu/h                    multiple,
                                                                 Btu/h
------------------------------------------------------------------------
<20,000......................................................        100
>=20,000 and <38,000.........................................        200
>=38,000 and <65,000.........................................        500
>=65,000.....................................................      1,000
------------------------------------------------------------------------

    The following sections of this appendix provide additional 
instructions for testing. In cases where there is a conflict, the 
language of this appendix takes highest precedence, followed by AHRI 
1250-2020, then ANSI/ASHRAE 37 or ANSI/ASHRAE 16. Any subsequent 
amendment to a referenced document by the standard-setting 
organization will not affect the test procedure in this appendix, 
unless and until the test procedure is amended by DOE. Material is 
incorporated as it exists on the date of the approval, and a 
notification of any change in the incorporation will be published in 
the Federal Register.

3.1. Instrumentation Accuracy and Test Tolerances

    Use measuring instruments as described in section 4.1 of AHRI 
1250-2020, with the following additional requirement.
    3.1.1. Electrical Energy Input measured in Wh with a minimum 
accuracy of 0.5% of reading (for Off-Cycle tests per 
footnote 5 of Table C3 in section C3.6.2 of AHRI 1250-2020).

3.2. Test Operating Conditions

    Test conditions used to determine AWEF2 shall be as specified in 
Tables 4 through 17 of AHRI 1250-2020. Tables 7 and 11 of AHRI 1250-
2020, labeled to apply to variable-speed outdoor matched-pair 
refrigeration systems, shall also be used for testing variable-
capacity single-packaged outdoor refrigeration systems, and also for 
testing multiple-capacity matched-pair or single-packaged outdoor 
refrigeration systems. Test conditions used to determine AWEF2 for 
refrigeration systems not specifically identified in AHRI 1250-2020 
are as enumerated in sections 3.5.1 through 3.5.6 of this appendix.

3.2.1 Test Operating Conditions for High-Temperature Refrigeration 
Systems

    For fixed-capacity high-temperature matched-pair or single-
packaged refrigeration systems with indoor condensing units, conduct 
tests using the test conditions specified in table 2 of this 
appendix. For fixed-capacity high-temperature matched-pair or 
single-packaged refrigeration systems with outdoor condensing units, 
conduct tests using the test conditions specified in table 3 of this 
appendix. For high-temperature unit coolers tested alone, conduct 
tests using the test conditions specified in table 4 of this 
appendix.

[[Page 28851]]



           Table 2--Test Operating Conditions for Fixed-Capacity High-Temperature Indoor Matched Pair or Single-Packaged Refrigeration Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Unit cooler
                                          Unit cooler      air       Condenser    Condenser
                                              air        entering       air          air
            Test description                entering     relative     entering     entering          Compressor status              Test objective
                                           dry-bulb,   humidity, %   dry-bulb,    wet-bulb,
                                             [deg]F        \1\         [deg]F       [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power.........................           55           55  ...........  ...........  Compressor Off................  Measure total input
                                                                                                                               wattage during compressor
                                                                                                                               off-cycle, (Ecu,off +
                                                                                                                               EFcomp,off).\2\
Refrigeration Capacity A................           55           55           90  \3\ 75, \4\  Compressor On.................  Determine Net
                                                                                          65                                   Refrigeration Capacity of
                                                                                                                               Unit Cooler, input power,
                                                                                                                               and EER at Test
                                                                                                                               Condition.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ The test condition tolerance (maximum permissible variation of the average value of the measurement from the specified test condition) for relative
  humidity is 3%.
\2\ Measure off-cycle power as described in sections C3 and C4.2 of AHRI 1250-2020.
\3\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\4\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units, where all or part of the equipment is
  located in the outdoor room.


          Table 3--Test Operating Conditions for Fixed-Capacity High-Temperature Outdoor Matched-Pair or Single-Packaged Refrigeration Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Unit cooler
                                          Unit cooler      air       Condenser    Condenser
                                              air        entering       air          air
            Test description                entering     relative     entering     entering          Compressor status              Test objective
                                           dry-bulb,   humidity, %   dry-bulb,    wet-bulb,
                                             [deg]F        \1\         [deg]F       [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refrigeration Capacity A................           55           55           95  \3\ 75, \4\  Compressor On.................  Determine Net
                                                                                          68                                   Refrigeration Capacity of
                                                                                                                               Unit Cooler, input power,
                                                                                                                               and EER at Test
                                                                                                                               Condition.
Off-Cycle Power, Capacity A \5\.........           55           55           95  \3\ 75, \4\  Compressor Off................  Measure total input
                                                                                          68                                   wattage during compressor
                                                                                                                               off-cycle, (Ecu,off +
                                                                                                                               EFcomp,off).\2\
Refrigeration Capacity B................           55           55           59  \3\ 54, \4\  Compressor On.................  Determine Net
                                                                                          46                                   Refrigeration Capacity of
                                                                                                                               Unit Cooler and system
                                                                                                                               input power at moderate
                                                                                                                               condition.
Off-Cycle Power, Capacity B \5\.........           55           55           59  \3\ 54, \4\  Compressor Off................  Measure total input
                                                                                          46                                   wattage during compressor
                                                                                                                               off-cycle, (Ecu,off +
                                                                                                                               EFcomp,off).\2\
Refrigeration Capacity C................           55           55           35  \3\ 34, \4\  Compressor On.................  Determine Net
                                                                                          29                                   Refrigeration Capacity of
                                                                                                                               Unit Cooler and system
                                                                                                                               input power at cold
                                                                                                                               condition.
Off-Cycle Power, Capacity C \5\.........           55           55           35  \3\ 34, \4\  Compressor Off................  Measure total input
                                                                                          29                                   wattage during compressor
                                                                                                                               off-cycle, (Ecu,off +
                                                                                                                               EFcomp,off).\2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ The test condition tolerance (maximum permissible variation of the average value of the measurement from the specified test condition) for relative
  humidity is 3%.
\2\ Measure off-cycle power as described in sections C3 and C4.2 of AHRI 1250-2020.
\3\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\4\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units, where all or part of the equipment is
  located in the outdoor room.


                                          Table 4--Test Operating Conditions for High-Temperature Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                 Unit cooler
                                    Unit cooler      air      Suction dew   Liquid inlet      Liquid
                                        air        entering   point temp,   bubble point      inlet
         Test description             entering     relative    [deg]F \3\   temperature,   subcooling,      Compressor status          Test objective
                                     dry-bulb,   humidity, %      \4\          [deg]F         [deg]F
                                       [deg]F        \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle.........................           55           55  ...........             105            9  Compressor Off...........  Measure unit cooler
                                                                                                                                    input wattage during
                                                                                                                                    compressor off-
                                                                                                                                    cycle, EF.\2\
Refrigeration Capacity............           55           55           38             105            9  Compressor On............  Determine Net
                                                                                                                                    Refrigeration
                                                                                                                                    Capacity of Unit
                                                                                                                                    Cooler, input power,
                                                                                                                                    and EER at Test
                                                                                                                                    Condition.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ The test condition tolerance (maximum permissible variation of the average value of the measurement from the specified test condition) for relative
  humidity is 3%.
\2\ Measure off-cycle power as described in sections C3 and C4.2 of AHRI 1250-2020.
\3\ Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.
\4\ Suction Dew Point shall be measured at the Unit Cooler Exit.

3.2.2 Test Operating Conditions for CO2 Unit Coolers

    For medium-temperature CO2 Unit Coolers, conduct 
tests using the test conditions specified in table 5 of this 
appendix. For low-temperature CO2 Unit Coolers, conduct 
tests using the test conditions specified in table 6 of this 
appendix.

                                       Table 5--Test Operating Conditions for Medium-Temperature CO2 Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                    Unit cooler  Unit cooler
                                        air          air      Suction dew   Liquid inlet      Liquid
            Test title                entering     entering      point      bubble point      inlet     Compressor operating mode      Test objective
                                     dry-bulb,     relative     temp,\3\    temperature,   subcooling,
                                       [deg]F    humidity, %     [deg]F        [deg]F         [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power...................           35          <50  ...........  ..............  ...........  Compressor On............  Measure unit cooler
                                                                                                                                    input wattage during
                                                                                                                                    compressor off-
                                                                                                                                    cycle, EF.\2\

[[Page 28852]]

 
Refrigeration Capacity, Ambient              35          <50           25              38            5  Compressor Off...........  Determine Net
 Condition A.                                                                                                                       Refrigeration
                                                                                                                                    Capacity of Unit
                                                                                                                                    Cooler, q.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.
\2\ Measure off-cycle power as described in sections C3 and C4.2 of AHRI 1250-2020.
\3\ Suction Dew Point shall be measured at the Unit Cooler Exit conditions.


                                         Table 6--Test Operating Conditions for Low-Temperature CO2 Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                    Unit cooler  Unit cooler
                                        air          air      Suction dew   Liquid inlet      Liquid
            Test title                entering     entering      point      bubble point      inlet     Compressor operating mode      Test objective
                                     dry-bulb,     relative     temp,\2\    temperature,   subcooling,
                                       [deg]F    humidity, %     [deg]F        [deg]F         [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power...................          -10          <50  ...........  ..............  ...........  Compressor Off...........  Measure unit cooler
                                                                                                                                    input wattage during
                                                                                                                                    compressor off-
                                                                                                                                    cycle, EF.\2\
Refrigeration Capacity, Ambient             -10          <50          -20              38            5  Compressor On............  Determine Net
 Condition A.                                                                                                                       Refrigeration
                                                                                                                                    Capacity of Unit
                                                                                                                                    Cooler, q.
Defrost...........................          -10          <50  ...........  ..............  ...........  Compressor Off...........  Test according to
                                                                                                                                    Appendix C Section
                                                                                                                                    C10 of AHRI 1250-
                                                                                                                                    2020, DF,Q.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.
\2\ Measure off-cycle power as described in sections C3 and C4.2 of AHRI 1250-2020.
\3\ Suction Dew Point shall be measured at the Unit Cooler Exit conditions.

3.2.3 Test Operating Conditions for Two-Capacity Condensing Units 
Tested Alone

    For two-capacity medium-temperature outdoor condensing units 
tested alone, conduct tests using the test conditions specified in 
table 7 of this appendix. For two-capacity medium-temperature indoor 
condensing units tested alone, conduct tests using the test 
conditions specified in table 8 of this appendix. For two-capacity 
low-temperature outdoor condensing units tested alone, conduct tests 
using the test conditions specified in table 9 of this appendix. For 
two-capacity low-temperature indoor condensing units tested alone, 
conduct tests using the test conditions specified in table 10 of 
this appendix.

    Table 7--Test Operating Conditions for Two-Capacity Medium-Temperature Outdoor Dedicated Condensing Units
----------------------------------------------------------------------------------------------------------------
                                                                                 Condenser air
                                  Suction dew     Return gas,    Condenser air   entering wet-     Compressor
       Test description          point, [deg]F      [deg]F       entering dry-   bulb, [deg]F        status
                                                                 bulb, [deg]F         \1\
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low                  24              41              95              75  Low Capacity,
 Capacity.                                                                                       k=1.
Capacity, Condition A, High                 23              41              95              75  High Capacity,
 Capacity.                                                                                       k=2.
Off-Cycle, Condition A........  ..............  ..............              95              75  Off.
Capacity, Condition B, Low                  24              41              59              54  Low Capacity,
 Capacity.                                                                                       k=1.
Capacity, Condition B, High                 23  ..............              59              54  High Capacity,
 Capacity.                                                                                       k=2.
Off-Cycle, Condition B........  ..............  ..............              59              54  Off.
Capacity, Condition C, Low                  24              41              35              34  Low Capacity,
 Capacity.                                                                                       k=1.
Capacity, Condition C, High                 23              41              35              34  High Capacity,
 Capacity.                                                                                       k=2.
Off-Cycle, Condition C........  ..............  ..............              35              34  Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).


    Table 8--Test Operating Conditions for Two-Capacity Medium-Temperature Indoor Dedicated Condensing Units
----------------------------------------------------------------------------------------------------------------
                                                                                 Condenser air
                                  Suction dew     Return gas,    Condenser air   entering wet-     Compressor
       Test description          point, [deg]F      [deg]F       entering dry-   bulb, [deg]F        status
                                                                 bulb, [deg]F         \1\
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low                  24              41              90              75  Low Capacity,
 Capacity.                                                                                       k=1.
Capacity, Condition A, High                 23              41              90              75  High Capacity,
 Capacity.                                                                                       k=2.
Off-Cycle, Condition A........  ..............  ..............              90              75  Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).


[[Page 28853]]


     Table 9--Test Operating Conditions for Two-Capacity Low-Temperature Outdoor Dedicated Condensing Units
----------------------------------------------------------------------------------------------------------------
                                                                                 Condenser air
                                  Suction dew     Return gas,    Condenser air   entering wet-     Compressor
          Test title             point, [deg]F      [deg]F       entering dry-   bulb, [deg]F    operating mode
                                                                 bulb, [deg]F         \1\
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low                 -22               5              95              75  Low Capacity,
 Capacity.                                                                                       k=1.
Capacity, Condition A, High                -22               5              95              75  High Capacity,
 Capacity.                                                                                       k=2.
Off-Cycle, Condition A........  ..............  ..............              95              75  Compressor Off.
Capacity, Condition B, Low                 -22               5              59              54  Low Capacity,
 Capacity.                                                                                       k=1.
Capacity, Condition B, High                -22               5              59              54  High Capacity,
 Capacity.                                                                                       k=2.
Off-Cycle, Condition B........  ..............  ..............              59              54  Compressor Off.
Capacity, Condition C, Low                 -22               5              35              34  Low Capacity,
 Capacity.                                                                                       k=1.
Capacity, Condition C, High                -22               5              35              34  Maximum
 Capacity.                                                                                       Capacity, k=2.
Off-Cycle, Condition C........  ..............  ..............              35              34  Compressor Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).


     Table 10--Test Operating Conditions for Two-Capacity Low-Temperature Indoor Dedicated Condensing Units
----------------------------------------------------------------------------------------------------------------
                                                                                 Condenser air
                                  Suction dew     Return gas,    Condenser air   entering wet-     Compressor
          Test title             point, [deg]F      [deg]F       entering dry-   bulb, [deg]F    operating mode
                                                                 bulb, [deg]F         \1\
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low                 -22               5              90              75  Low Capacity,
 Capacity.                                                                                       k=1.
Capacity, Condition A, High                -22               5              90              75  High Capacity,
 Capacity.                                                                                       k=2.
Off-Cycle, Condition A........  ..............  ..............              90              75  Compressor Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).

3.2.4 Test Operating Conditions for Variable- or Multiple-Capacity 
Condensing Units Tested Alone

    For variable-capacity or multiple-capacity outdoor medium-
temperature condensing units tested alone, conduct tests using the 
test conditions specified in table 11 of this appendix. For 
variable-capacity or multiple-capacity indoor medium-temperature 
condensing units tested alone, conduct tests using the test 
conditions specified in table 12 of this appendix. For variable-
capacity or multiple-capacity outdoor low-temperature condensing 
units tested alone, conduct tests using the test conditions 
specified in table 13 of this appendix. For variable-capacity or 
multiple-capacity indoor low-temperature condensing units tested 
alone, conduct tests using the test conditions specified in table 14 
of this appendix.

   Table 11--Test Operating Conditions for Variable- or Multiple-Capacity Medium-Temperature Outdoor Dedicated
                                                Condensing Units
----------------------------------------------------------------------------------------------------------------
                                                                                 Condenser air
                                  Suction dew     Return gas,    Condenser air   entering wet-     Compressor
       Test description          point, [deg]F      [deg]F       entering dry-   bulb, [deg]F        status
                                                                 bulb, [deg]F         \1\
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum              24              41              95              75  Minimum
 Capacity.                                                                                       Capacity, k=1.
Capacity, Condition A,                      24              41              95              75  Intermediate
 Intermediate Capacity.                                                                          Capacity, k=i.
Capacity, Condition A, Maximum              23              41              95              75  Maximum
 Capacity.                                                                                       Capacity, k=2
Off-Cycle, Condition A........  ..............  ..............              95              75  Off.
Capacity, Condition B, Minimum              24              41              59              54  Minimum
 Capacity.                                                                                       Capacity, k=1.
Capacity, Condition B,                      24              41              59              54  Intermediate
 Intermediate Capacity.                                                                          Capacity, k=i.
Capacity, Condition B, Maximum              23              41              59              54  Maximum
 Capacity.                                                                                       Capacity, k=2.
Off-Cycle, Condition B........  ..............  ..............              59              54  Off.
Capacity, Condition C, Minimum              24              41              35              34  Minimum
 Capacity.                                                                                       Capacity, k=1.
Capacity, Condition C,                      24              41              35              34  Intermediate
 Intermediate Capacity.                                                                          Capacity, k=i.
Capacity, Condition C, Maximum              23              41              35              34  Maximum
 Capacity.                                                                                       Capacity, k=2.
Off-Cycle, Condition C........  ..............  ..............              35              34  Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).


[[Page 28854]]


   Table 12--Test Operating Conditions for Variable- or Multiple-Capacity Medium-Temperature Indoor Dedicated
                                                Condensing Units
----------------------------------------------------------------------------------------------------------------
                                                                                 Condenser air
                                  Suction dew     Return gas,    Condenser air   entering wet-     Compressor
       Test description          point, [deg]F      [deg]F       entering dry-   bulb, [deg]F        status
                                                                 bulb, [deg]F         \1\
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum              24              41              90              75  Minimum
 Capacity.                                                                                       Capacity, k=1.
Capacity, Condition A,                      24              41              90              75  Intermediate
 Intermediate Capacity.                                                                          Capacity, k=i.
Capacity, Condition A, Maximum              23              41              90              75  Maximum
 Capacity.                                                                                       Capacity, k=2.
Off-Cycle, Condition A........  ..............  ..............              90              75  Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).


    Table 13--Test Operating Conditions for Variable- or Multiple-Capacity Low-Temperature Outdoor Dedicated
                                                Condensing Units
----------------------------------------------------------------------------------------------------------------
                                                                                 Condenser air
                                  Suction dew     Return gas,    Condenser air   entering wet-     Compressor
          Test title             point, [deg]F      [deg]F       entering dry-   bulb, [deg]F    operating mode
                                                                 bulb, [deg]F         \1\
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum             -22               5              95              75  Minimum
 Capacity.                                                                                       Capacity, k=1.
Capacity, Condition A,                     -22               5              95              75  Minimum
 Intermediate Capacity.                                                                          Capacity, k=i.
Capacity, Condition A, Maximum             -22               5              95              75  Maximum
 Capacity.                                                                                       Capacity, k=2.
Off-Cycle, Condition A........  ..............  ..............              95              75  Compressor Off.
Capacity, Condition B, Minimum             -22               5              59              54  Minimum
 Capacity.                                                                                       Capacity, k=1.
Capacity, Condition B,                     -22               5              59              54  Minimum
 Intermediate Capacity.                                                                          Capacity, k=i.
Capacity, Condition B, Maximum             -22               5              59              54  Maximum
 Capacity.                                                                                       Capacity, k=2.
Off-Cycle, Condition B........  ..............  ..............              59              54  Compressor Off.
Capacity, Condition C, Minimum             -22               5              35              34  Minimum
 Capacity.                                                                                       Capacity, k=1.
Capacity, Condition C,                     -22               5              35              34  Minimum
 Intermediate Capacity.                                                                          Capacity, k=i.
Capacity, Condition C, Maximum             -22               5              35              34  Maximum
 Capacity.                                                                                       Capacity, k=2
Off-Cycle, Condition C........  ..............  ..............              35              34  Compressor Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).


     Table 14--Test Operating Conditions for Variable- or Multiple-Capacity Low-Temperature Indoor Dedicated
                                                Condensing Units
----------------------------------------------------------------------------------------------------------------
                                                                                 Condenser air
                                  Suction dew     Return gas,    Condenser air   entering wet-     Compressor
          Test title             point, [deg]F      [deg]F       entering dry-   bulb, [deg]F    operating mode
                                                                 bulb, [deg]F         \1\
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum             -22               5              90              75  Minimum
 Capacity.                                                                                       Capacity, k=1.
Capacity, Condition A,                     -22               5              90              75  Minimum
 Intermediate Capacity.                                                                          Capacity, k=i.
Capacity, Condition A, Maximum             -22               5              90              75  Maximum
 Capacity.                                                                                       Capacity, k=2.
Off-Cycle, Condition A........  ..............  ..............              90              75  Compressor Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).

3.2.5 Test Operating Conditions for Two-Capacity Indoor Matched-Pair or 
Single-Packaged Refrigeration Systems

    For two-capacity indoor medium-temperature matched-pair or 
single-packaged refrigeration systems, conduct tests using the test 
conditions specified in table 15 of this appendix. For two-capacity 
indoor low-temperature matched-pair or single-packaged refrigeration 
systems, conduct tests using the test conditions specified in table 
16 of this appendix.

[[Page 28855]]



 Table 15--Test Operating Conditions for Two-Capacity Medium-Temperature Indoor Matched-Pair or Single-Packaged
                                              Refrigeration Systems
----------------------------------------------------------------------------------------------------------------
                                  Unit cooler     Unit cooler
                                 air entering    air entering    Condenser air   Condenser air     Compressor
       Test description            dry-bulb,       relative      entering dry-   entering wet-       status
                                    [deg]F        humidity, %    bulb, [deg]F    bulb, [deg]F
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low                  35             <50              90  \1\ 75, \2\ 65  Low Capacity.
 Capacity.
Capacity, Condition A, High                 35             <50              90  \1\ 75, \2\ 65  High Capacity.
 Capacity.
Off-Cycle, Condition A........              35             <50              90  \1\ 75, \2\ 65  Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units,
  where all or part of the equipment is located in the outdoor room.


   Table 16--Test Operating Conditions for Two Capacity Low-Temperature Indoor Matched-Pair or Single-Packaged
                                              Refrigeration Systems
----------------------------------------------------------------------------------------------------------------
                                  Unit cooler     Unit cooler                       Maximum
                                 air entering    air entering    Condenser air   condenser air     Compressor
       Test description            dry-bulb,       relative      entering dry-   entering wet-       status
                                    [deg]F        humidity, %    bulb, [deg]F    bulb, [deg]F
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low                 -10             <50              90   \1\ 75, \2\65  Low Capacity.
 Capacity.
Capacity, Condition A, High                -10             <50              90  \1\ 75, \2\ 65  High Capacity.
 Capacity.
Off-Cycle, Condition A........             -10             <50              90  \1\ 75, \2\ 65  Off.
Defrost.......................             -10             <50  ..............  ..............  System
                                                                                                 Dependent.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units,
  where all or part of the equipment is located in the outdoor room.

3.2.6 Test Conditions for Variable- or Multiple-Capacity Indoor Matched 
Pair or Single-Packaged Refrigeration Systems

    For variable- or multiple-capacity indoor medium-temperature 
matched-pair or single-packaged refrigeration systems, conduct tests 
using the test conditions specified in table 17 of this appendix. 
For variable- or multiple-capacity indoor low-temperature matched-
pair or single-packaged refrigeration systems, conduct tests using 
the test conditions specified in table 18 of this appendix.

Table 17--Test Operating Conditions for Variable- or Multiple-Capacity Medium-Temperature Indoor Matched-Pair or
                                      Single-Packaged Refrigeration Systems
----------------------------------------------------------------------------------------------------------------
                                  Unit cooler     Unit cooler
                                 air entering    air entering    Condenser air  Condenser  air     Compressor
       Test description            dry-bulb,       relative      entering dry-   entering wet-       status
                                    [deg]F        humidity, %    bulb, [deg]F    bulb, [deg]F
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum              35             <50              90  \1\ 75, \2\ 65  Minimum
 Capacity.                                                                                       Capacity.
Capacity, Condition A,                      35             <50              90  \1\ 75, \2\ 65  Intermediate
 Intermediate Capacity.                                                                          Capacity.
Capacity, Condition A, High                 35             <50              90  \1\ 75, \1\ 65  Maximum
 Capacity.                                                                                       Capacity.
Off-Cycle, Condition A........              35             <50              90  \1\ 75, \2\ 65  Off.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units,
  where all or part of the equipment is located in the outdoor room.


  Table 18--Test Operating Conditions for Variable- or Multiple-Capacity Low-Temperature Indoor Matched-Pair or
                                      Single-Packaged Refrigeration Systems
----------------------------------------------------------------------------------------------------------------
                                  Unit cooler     Unit cooler                       Maximum
                                 air entering    air entering    Condenser air   condenser air     Compressor
       Test description            dry-bulb,       relative      entering dry-   entering wet-       status
                                    [deg]F        humidity, %    bulb, [deg]F    bulb, [deg]F
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum             -10             <50              90  \1\ 75, \2\ 65  Minimum
 Capacity.                                                                                       Capacity.
Capacity, Condition A,                     -10             <50              90  \1\ 75, \2\ 65  Intermediate
 Intermediate Capacity.                                                                          Capacity.
Capacity, Condition A, Maximum             -10             <50              90  \1\ 75, \2\ 65  Maximum
 Capacity.                                                                                       Capacity.
Off-Cycle, Condition A........             -10             <50              90  \1\ 75, \2\ 65  Off.

[[Page 28856]]

 
Defrost.......................             -10             <50  ..............  ..............  System
                                                                                                 Dependent.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units,
  where all or part of the equipment is located in the outdoor room.

3.3 Calculation for Walk-in Box Load

    3.3.1 For medium- and low-temperature refrigeration systems with 
indoor condensing units, calculate walk-in box loads for high and 
low load periods as a function of net capacity as described in 
section 6.2.1 of AHRI 1250-2020.
    3.3.2 For medium- and low-temperature refrigeration systems with 
outdoor condensing units, calculate walk-in box loads for high and 
low load periods as a function of net capacity and outdoor 
temperature as described in section 6.2.2 of AHRI 1250-2020.
    3.3.3 For high-temperature refrigeration systems, calculate 
walk-in box load as follows.

BL = 0.5 [middot] qss,A

Where qss,A is the measured net capacity for Test Condition A.

3.4 Calculation for Annual Walk-in Energy Factor (AWEF2)

    Calculations used to determine AWEF2 based on performance data 
obtained for testing shall be as specified in section 7 of AHRI 
1250-2020 with modifications as indicated in sections 3.4.7 through 
3.4.10 of this appendix. Calculations used to determine AWEF2 for 
refrigeration systems not specifically identified in sections 7.1.1 
through 7.1.6 of AHRI 1250-2020 are enumerated in sections 3.4.1 
through 3.4.6 and 3.4.11 through 3.4.14 of this appendix.

3.4.1 Two-Capacity Condensing Units Tested Alone, Indoor

    3.4.1.1 Unit Cooler Power
    Calculate maximum-capacity unit cooler power during the 
compressor on period EFcomp,on, in Watts, using Equation 130 of AHRI 
1250-2020 for medium-temperature refrigeration systems and using 
Equation 173 of AHRI 1250-2020 for low-temperature refrigeration 
systems.
    Calculate unit cooler power during the compressor off period 
EFcomp,off, in Watts, as 20 percent of the maximum-capacity unit 
cooler power during the compressor on period.
    3.4.1.2 Defrost
    For freezer refrigeration systems, calculate defrost heat 
contribution QDF in Btu/h and the defrost average power consumption 
DF in W as a function of steady-state maximum gross refrigeration 
capacity Qgrossk=2, as specified in section C10.2.2 of 
Appendix C of AHRI 1250-2020.
    3.4.1.3 Net Capacity
    Calculate steady-state maximum net capacity, qssk=2, 
and minimum net capacity, qssk=1 as follows:

qssk=2 = Qgrossk=2 - 3412 [middot] EFcomp,on

qssk=1 = Qgrossk=1 - 3412 [middot] 0.2 
[middot] EFcomp,on

Where:

Qgrossk=2 and Qgrossk=1 represent gross 
refrigeration capacity at maximum and minimum capacity, 
respectively.

    3.4.1.4 Calculate average power input during the low load period 
as follows.
    If the low load period box load, BLL, plus defrost heat 
contribution, QDF (only applicable for freezers), is less than the 
minimum net capacity qssk=1:
[GRAPHIC] [TIFF OMITTED] TR04MY23.032

Where:

Essk=1 is the steady state condensing unit power input 
for minimum-capacity operation.
Ecu,off is the condensing unit off-cycle power input, measured as 
described in section C3.5 of AHRI 1250-2020.

    If the low load period box load, BLL, plus defrost heat 
contribution, QDF, (only applicable for freezers) is greater than 
the minimum net capacity qssk=1:
[GRAPHIC] [TIFF OMITTED] TR04MY23.033


[[Page 28857]]


    3.4.1.5 Calculate average power input during the high load 
period as follows.
[GRAPHIC] [TIFF OMITTED] TR04MY23.034

    3.4.1.6 Calculate the AWEF2 as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.035
    
3.4.2 Variable-Capacity or Multistage Condensing Units Tested Alone, 
Indoor

    3.4.2.1 Unit Cooler Power
    Calculate maximum-capacity unit cooler power during the 
compressor on period EFcomp,on as described in section 3.4.1.1 of 
this appendix.
    Calculate unit cooler power during the compressor off period 
EFcomp,off, in Watts, as 20 percent of the maximum-capacity unit 
cooler power during the compressor on period.
    3.4.2.2 Defrost
    Calculate Defrost parameters as described in section 4.4.1.2 of 
this appendix.
    3.4.2.3 Net Capacity
    Calculate steady-state maximum net capacity, qssk=2, 
intermediate net capacity, qssk=i, and minimum net capacity, 
qssk=1 as follows:

qssk=2 = Qgrossk=2 - 3412 [middot] EFcomp,on
qssk=2 = Qgrossk=2 - 3412 [middot] Kf [middot] 
EFcomp,on
qssk=1 = Qgrossk=1 - 3412 [middot] 0.2 
[middot] EFcomp,on

Where:

Qgrossk=2, Qgrossk=i, Qgross,k=1, and 
represent gross refrigeration capacity at maximum, intermediate, and 
minimum capacity, respectively.

    Kf is the unit cooler power coefficient for 
intermediate capacity operation, set equal to 0.2 to represent low-
speed fan operation if the Duty Cycle for a Digital Compressor, the 
Speed Ratio for a Variable-Speed Compressor, or the Displacement 
Ratio for a Multi-Stage Compressor at Intermediate Capacity is 65% 
or less, and otherwise set equal to 1.0.
    3.4.2.4 Calculate average power input during the low load period 
as follows.
    If the low load period box load, BLL, plus defrost heat 
contribution QDF (only applicable for freezers) is less than the 
minimum net capacity qssk=1:
[GRAPHIC] [TIFF OMITTED] TR04MY23.036

    Where Ecu,off, in W, is the condensing unit off-mode power 
consumption, measured as described in section C3.5 of AHRI 1250-
2020.
    If the low load period box load BLL plus defrost heat 
contribution QDF (only applicable for freezers) is greater than the 
minimum net capacity qssk=1 and less than the 
intermediate net capacity qssk=i:
[GRAPHIC] [TIFF OMITTED] TR04MY23.037

Where:

EERk=1 is the minimum-capacity energy efficiency ratio, 
equal to qssk=1 divided by Essk=1 + 0.2 
[middot] EFcomp,on; and
EERk=i is the intermediate-capacity energy efficiency 
ratio, equal to qssk=i divided by Essk=i + Kf [middot] EFcomp,on.
    3.4.2.5 Calculate average power input during the high load 
period as follows:
    If the high load period box load, BLH, plus defrost heat 
contribution, QDF (only applicable for freezers), is greater than 
the minimum net capacity qssk=1 and less than the 
intermediate net capacity qssk=i:

[[Page 28858]]

[GRAPHIC] [TIFF OMITTED] TR04MY23.038

    If the high load period box load, BLH, plus defrost heat 
contribution, QDF (only applicable for freezers), is greater than 
the intermediate net capacity, qssk=i, and less than the 
maximum net capacity, qssk=2:
[GRAPHIC] [TIFF OMITTED] TR04MY23.039

Where:

EERk=2 is the maximum-capacity energy efficiency ratio, equal to 
qssk=2 divided by Essk=2 + EFcomp,on

    3.4.2.6 Calculate the AWEF2 as follows.
    [GRAPHIC] [TIFF OMITTED] TR04MY23.040
    
3.4.3 Two-Capacity Condensing Units Tested Alone, Outdoor

    3.4.3.1 Unit Cooler Power
    Calculate maximum-capacity unit cooler power during the 
compressor on period EFcomp,on, in Watts, using Equation 153 of AHRI 
1250-2020 for medium-temperature refrigeration systems and using 
Equation 196 of AHRI 1250-2020 for low-temperature refrigeration 
systems.
    Calculate unit cooler power during the compressor off period 
EFcomp,off, in Watts, as 20 percent of the maximum-capacity unit 
cooler power during the compressor on period.
    3.4.3.2 Defrost
    Calculate Defrost parameters as described in section 3.4.1.2 of 
this appendix.
    3.4.3.3 Condensing Unit Off-Cycle Power
    Calculate Condensing Unit Off-Cycle Power for temperature 
tj as follows.
[GRAPHIC] [TIFF OMITTED] TR04MY23.041

Where Ecu,off,A and Ecu,off,C are the Condensing Unit off-cycle 
power measurements for test conditions A and C, respectively, 
measured as described in section C3.5 of AHRI 1250-2020. If 
tj is greater than 35 [deg]F and less than 59 [deg]F, use 
Equation 157 of AHRI 1250-2020, and if tj is greater than 
or equal to 59 [deg]F and less than 95 [deg]F, use Equation 159 of 
AHRI 1250-2020.

    3.4.3.4 Net Capacity and Condensing Unit Power Input
    Calculate steady-state maximum net capacity, 
qssk=2(tj), and minimum net capacity, 
qssk=1(tj), and corresponding condensing unit power input 
levels Essk=2(tj) and Essk=1(tj) as a function 
of outdoor temperature tj as follows:
    If tj <= 59 [deg]F:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.042
    

[[Page 28859]]


    If 59 [deg]F < tj:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.043
    
Where:

The capacity level k can equal 1 or 2;
Qgross,Xk=2 and Qgross,Xk=1 represent gross 
refrigeration capacity at maximum and minimum capacity, 
respectively, for test condition X, which can take on values A, B, 
or C;
Ess,Xk=2 and Ess,Xk=1 represent condensing 
unit power input at maximum and minimum capacity, respectively for 
test condition X.

    3.4.3.5 Calculate average power input during the low load period 
as follows.
    Calculate the temperature, tIL, in the following 
equation which the low load period box load, BLL(tj), plus defrost 
heat contribution, QDF (only applicable for freezers), is less than 
the minimum net capacity, qssk=1(tj), by solving the 
following equation for tIL:

BLL(tIL) + QDF = qssk=1(tIL)

    For tj < tIL:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.044
    
    Where Ecu,off(tj), in W, is the condensing unit off-mode power 
consumption for temperature tj, determined as indicated 
in section 3.4.3.3 of this appendix.

    For tj >= tIL:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.045
    
    3.4.3.6 Calculate average power input during the high load 
period as follows.
    Calculate the temperature, tIH, in the following 
equation which the high load period box load, BLH(tj), plus defrost 
heat contribution, QDF (only applicable for freezers), is less than 
the minimum net capacity, qssk=1(tj) , by solving the 
following equation for tIH:

BLH(tIH) + QDF = qssk=1(tIH)

    Calculate the temperature, tIIH, in the following 
equation which the high load period box load BLH(tj) plus defrost 
heat contribution QDF (only applicable for freezers) is less than 
the maximum net capacity qssk=2(tj), by solving the 
following equation for tIIH:

BLH(tIIH) + QDF = qssk=1(tIIH)

    For tj < tIH:

[[Page 28860]]

[GRAPHIC] [TIFF OMITTED] TR04MY23.046

    For tIH <= tj < tIIH:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.047
    
    For tIIH <= tj:

EH(tj) = (Essk=2(tj) + EFcomp,on)

    3.4.3.7 Calculate the AWEF2 as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.048
    
3.4.4 Variable-Capacity or Multistage Condensing Units Tested Alone, 
Outdoor

    3.4.4.1 Unit Cooler Power
    Calculate maximum-capacity unit cooler power during the 
compressor on period EFcomp,on as described in section 3.4.1.1 of 
this appendix.
    Calculate unit cooler power during the compressor off period 
EFcomp,on, in Watts, as 20 percent of the maximum-capacity unit 
cooler power during the compressor on period.
    3.4.4.2 Defrost
    Calculate Defrost parameters as described in section 3.4.1.2 of 
this appendix.
    3.4.4.3 Condensing Unit Off-Cycle Power
    Calculate Condensing Unit Off-Cycle Power for temperature, 
tj, as described in section 3.4.3.3 of this appendix.
    3.4.4.4 Net Capacity and Condensing Unit Power Input
    Calculate steady-state maximum net capacity, 
qssk=2(tj), intermediate net capacity, 
qssk=i(tj) , and minimum net capacity, 
qssk=1(tj), and corresponding condensing unit power input 
levels Essk=2(tj), Essk=i(tj), 
Essk=1(tj) and as a function of outdoor temperature, 
tj, as follows:
    If tj <= 59 [deg]F:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.049
    
    If 59 [deg]F < tj:

[[Page 28861]]

[GRAPHIC] [TIFF OMITTED] TR04MY23.050

Where:

The capacity level k can equal 1, i, or 2;
Qgross,Xk=2, Qgross,Xk=i and Qgross,Xk=1 
represent gross refrigeration capacity at maximum, intermediate, and 
minimum capacity, respectively, for test condition X, which can take 
on values A, B, or C;
Ess,Xk=2 and Ess,Xk=1 represent condensing 
unit power input at maximum and minimum capacity, respectively for 
test condition X; and
Kf is the unit cooler power coefficient for intermediate 
capacity operation, set equal to 0.2 to represent low-speed fan 
operation if the Duty Cycle for a Digital Compressor, the Speed 
Ratio for a Variable-Speed Compressor, or the Displacement Ratio for 
a Multi-Stage Compressor at Intermediate Capacity is 65% or less, 
and otherwise set equal to 1.0.

    3.4.4.5 Calculate average power input during the low load period 
as follows.
    Calculate the temperature, tIL, in the following 
equation which the low load period box load BLL(tj) plus defrost 
heat contribution, QDF (only applicable for freezers), is less than 
the minimum net capacity, qssk=1(tj), by solving the 
following equation for tIL:

BLL(tIL) + QDF = qssk=1(tIL)

    Calculate the temperature, tVL, in the following 
equation which the low load period box load, BLL(tj), plus defrost 
heat contribution, QDF (only applicable for freezers), is less than 
the intermediate net capacity, qssk=i(tj), by solving the 
following equation for tVL:

BLL(tVL) + QDF = qssk=i(tVL)

    For tj < tIL:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.051
    
    Where, Ecu,off(tj) in W, is the condensing unit off-mode power 
consumption for temperature, tj, determined as indicated 
in section 3.4.3.3 of this appendix.
    For tIL <= tj < tVL:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.052
    
    For tVL <= tj:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.053
    

[[Page 28862]]


Where:

EERk=2(tj) is the minimum-capacity energy efficiency 
ratio, equal to qssk=1(tj) divided by 
Essk=1(tj) + 0.2 EFcomp,on;
EER\k=i\(tj) is the intermediate-capacity energy 
efficiency ratio, equal to qssk=i(tj) divided by 
Essk=i(tj) + Kf [middot] EFcomp,on; and
EER\k=2\(tj) is the maximum-capacity energy efficiency 
ratio, equal to qssk=2(tj) divided by 
Essk=2(tj) + EFcomp,on

    3.4.4.6 Calculate average power input during the high load 
period as follows.
    Calculate the temperature tVH in the following 
equation which the high load period box load BLH(tj) plus defrost 
heat contribution QDF (only applicable for freezers) is less than 
the intermediate net capacity qssk=i(tj), by solving the 
following equation for tVH:

BLH(tVH) + QDF = qssk=i(tVH)

    Calculate the temperature tIIH in the following 
equation which the high load period box load BLH(tj) plus defrost 
heat contribution QDF (only applicable for freezers) is less than 
the maximum net capacity qssk=2(tj), by solving the 
following equation for tIIH:

BLH(tIIH) + QDF = qssk=2(tIIH)

    For tj < tVH:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.054
    
    For tVH <= tj < tIIH:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.055
    
    For tIIH <= tj:

EH(tj) = (Essk=2 (tj) + EFcomp,on)

    3.4.4.7 Calculate the AWEF2 as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.056
    
3.4.5 Two-Capacity Indoor Matched Pairs or Single-Packaged 
Refrigeration Systems Other Than High-Temperature

    3.4.5.1 Defrost
    For freezer refrigeration systems, defrost heat contribution QDF 
in Btu/h and the defrost average power consumption DF in W shall be 
as measured in accordance with section C10.2.1 of Appendix C of AHRI 
1250-2020.
    3.4.5.2 Calculate average power input during the low load period 
as follows.
    If the low load period box load BLL plus defrost heat 
contribution QDF (only applicable for freezers) is less than the 
minimum net capacity qssk=1:
[GRAPHIC] [TIFF OMITTED] TR04MY23.057

Where:

qssk=1 and Essk=1 are the steady state 
refrigeration system minimum net capacity, in Btu/h, and associated 
refrigeration system power input, in W, respectively, for minimum-
capacity operation, measured as described in AHRI 1250-2020.
EFcomp,off and Ecu,off, both in W, are the unit cooler and 
condensing unit, respectively, off-mode power consumption, measured 
as described in section C3.5 of AHRI 1250-2020.

    If the low load period box load BLL plus defrost heat 
contribution QDF (only applicable for freezers) is greater than the 
minimum net capacity qssk=1:

[[Page 28863]]

[GRAPHIC] [TIFF OMITTED] TR04MY23.058

Where qssk=2 and Essk=2 are the steady state 
refrigeration system maximum net capacity, in Btu/h, and associated 
refrigeration system power input, in W, respectively, for maximum-
capacity operation, measured as described in AHRI 1250-2020.
    3.4.5.3 Calculate average power input during the high load 
period as follows.
[GRAPHIC] [TIFF OMITTED] TR04MY23.059

    3.4.5.4 Calculate the AWEF2 as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.060
    
3.4.6 Variable-Capacity or Multistage Indoor Matched Pairs or Single-
Packaged Refrigeration Systems Other Than High-Temperature

    3.4.6.1 Defrost
    For freezer refrigeration systems, defrost heat contribution QDF 
in Btu/h and the defrost average power consumption DF in W shall be 
as measured in accordance with section C10.2.1 of Appendix C of AHRI 
1250-2020.
    3.4.6.2 Calculate average power input during the low load period 
as follows.
    If the low load period box load BLL plus defrost heat 
contribution QDF (only applicable for freezers) is less than the 
minimum net capacity qssk=1:
[GRAPHIC] [TIFF OMITTED] TR04MY23.061

Where:

qssk=1 and Essk=1 are the steady state 
refrigeration system minimum net capacity, in Btu/h, and associated 
refrigeration system power input, in W, respectively, for minimum-
capacity operation, measured as described in AHRI 1250-2020; and
EFcomp,off and Ecu,off, both in W, are the unit cooler and 
condensing unit, respectively, off-mode power consumption, measured 
as described in section C3.5 of AHRI 1250-2020.

    If the low load period box load BLL plus defrost heat 
contribution QDF (only applicable for freezers) is greater than the 
minimum net capacity and less than the intermediate net capacity 
qssk=i:
[GRAPHIC] [TIFF OMITTED] TR04MY23.062


[[Page 28864]]


Where:

EERk=1 is the minimum-capacity energy efficiency ratio, 
equal to qssk=1divided by Essk=1;
qssk=i and Essk=i are the steady state refrigeration system 
intermediate net capacity, in Btu/h, and associated refrigeration 
system power input, in W, respectively, for intermediate-capacity 
operation, measured as described in AHRI 1250-2020.
EERk=i is the intermediate-capacity energy efficiency 
ratio, equal to qssk=i divided by Essk=i.
    3.4.6.3 Calculate average power input during the high load 
period as follows.
    If the high load period box load BLH plus defrost heat 
contribution QDF (only applicable for freezers) is greater than the 
minimum net capacity qssk=1 and less than the 
intermediate net capacity qssk=i:
[GRAPHIC] [TIFF OMITTED] TR04MY23.063

    If the high load period box load BLH plus defrost heat 
contribution QDF (only applicable for freezers) is greater than the 
intermediate net capacity qssk=i and less than the maximum net 
capacity qssk=2:
[GRAPHIC] [TIFF OMITTED] TR04MY23.064

Where:

qssk=2 and Essk=2 are the steady state 
refrigeration system maximum net capacity, in Btu/h, and associated 
refrigeration system power input, in W, respectively, for maximum-
capacity operation, measured as described in AHRI 1250-2020; and
EER\k=2\ is the maximum-capacity energy efficiency ratio, equal to 
qssk=2 divided by Essk=2.
    3.4.6.4 Calculate the AWEF2 as follows.
    [GRAPHIC] [TIFF OMITTED] TR04MY23.065
    
3.4.7 Variable-Capacity or Multistage Outdoor Matched Pairs or Single-
Packaged Refrigeration Systems Other Than High-Temperature

    Calculate AWEF2 as described in section 7.6 of AHRI 1250-2020, 
with the following revisions.
    3.4.7.1 Condensing Unit Off-Cycle Power
    Calculate condensing unit off-cycle power for temperature 
tj as indicated in section 3.4.3.3 of this appendix. 
Replace the constant value ECU,off in Equations 55 and 70 of AHRI 
1250-2020 with the values ECU,off(tj), which vary with outdoor 
temperature tj.
    3.4.7.2 Unit Cooler Off-Cycle Power
    Set unit cooler Off-Cycle power EFcomp,off equal to the average 
of the unit cooler off-cycle power measurements made for test 
conditions A, B, and C.
    3.4.7.3 Average Power During the Low Load Period
    Calculate average power for intermediate-capacity compressor 
operation during the low load period Ess,Lk=v(tj) as described in 
section 7.6 of AHRI 1250-2020, except that, instead of calculating 
intermediate-capacity compressor EER using Equation 77 of AHRI 1250-
2020, calculate EER as follows.
    For tj < tVL:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.066
    
    For tVL <= tj:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.067
    

[[Page 28865]]


Where:

EERk=1(tj) is the minimum-capacity energy 
efficiency ratio, equal to qssk=1(tj) divided by 
Essk=1(tj);
EERk=i(tj) is the intermediate-capacity energy 
efficiency ratio, equal to qssk=i (tj) divided by Essk=i(tj); and
EERk=2(tj) is the maximum-capacity energy 
efficiency ratio, equal to qssk=2(tj) divided by 
Essk=2(tj)

    3.4.7.4 Average Power During the High Load Period
    Calculate average power for intermediate-capacity compressor 
operation during the high load period Ess,Hk=v(tj) as described in 
section 7.6 of AHRI 1250-2020, except that, instead of calculating 
intermediate-capacity compressor EER using Equation 61 of AHRI 1250-
2020, calculate EER as follows:
    For tj < tVH:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.068
    
    For tVH <= tj:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.069
    
3.4.8 Two-Capacity Outdoor Matched Pairs or Single-Packaged 
Refrigeration Systems Other Than High-Temperature

    Calculate AWEF2 as described in section 7.5 of AHRI 1250-2020, 
with the following revisions for Condensing Unit Off-Cycle Power and 
Unit Cooler Off-Cycle Power. Calculate condensing unit off-cycle 
power for temperature tj as indicated in section 3.4.3.3 
of this appendix. Replace the constant value ECU,off in Equations 13 
and 29 of AHRI 1250-2020 with the values ECU,off(tj), which vary 
with outdoor temperature tj. Set unit cooler Off-Cycle 
power EFcomp,off equal to the average of the unit cooler off-cycle 
power measurements made for test conditions A, B, and C.

3.4.9 Single-Capacity Outdoor Matched Pairs or Single-Packaged 
Refrigeration Systems Other Than High-Temperature

    Calculate AWEF2 as described in section 7.4 of AHRI 1250-2020, 
with the following revision for Condensing Unit Off-Cycle Power and 
Unit Cooler Off-cycle Power. Calculate condensing unit off-cycle 
power for temperature tj as indicated in section 3.4.3.3 
of this appendix. Replace the constant value ECU,off in Equations 13 
of AHRI 1250-2020 with the values ECU,off(tj), which vary with 
outdoor temperature tj. Set unit cooler Off-Cycle power 
EFcomp,off equal to the average of the unit cooler off-cycle power 
measurements made for test conditions A, B, and C.

3.4.10 Single-Capacity Condensing Units, Outdoor

    Calculate AWEF2 as described in section 7.9 of AHRI 1250-2020, 
with the following revision for Condensing Unit Off-Cycle Power. 
Calculate condensing unit off-cycle power for temperature 
tj as indicated in section 3.4.3.3 of this appendix 
rather than as indicated in Equations 157, 159, 202, and 204 of AHRI 
1250-2020.

3.4.11 High-Temperature Matched Pairs or Single-Packaged Refrigeration 
Systems, Indoor

    3.4.11.1 Calculate Load Factor LF as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.070
    
Where:

BL, in Btu/h is the non-equipment-related box load calculated as 
described in section 3.3.3 of this appendix;
EFcomp,off, in W, is the unit cooler off-cycle power consumption, 
equal to 0.1 times the unit cooler on-cycle power consumption; and
qss,A, in Btu/h is the measured net capacity for test condition A.
    3.4.11.2 Calculate the AWEF2 as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.071
    
Where:

Ess,A, in W, is the measured system power input for test condition 
A; and
Ecu,off, in W, is the condensing unit off-cycle power consumption, 
measured as described in section C3.5 of AHRI 1250-2020.

3.4.12 High-Temperature Matched Pairs or Single-Packaged Refrigeration 
Systems, Outdoor

    3.4.12.1 Calculate Load Factor LF(tj) for outdoor 
temperature tj as follows:
[GRAPHIC] [TIFF OMITTED] TR04MY23.072


[[Page 28866]]


Where:

BL, in Btu/h, is the non-equipment-related box load calculated as 
described in section 3.3.3 of this appendix;
EFcomp,off, in W, is the unit cooler off-cycle power consumption, 
equal to 0.1 times the unit cooler on-cycle power consumption; and
qss(tj), in Btu/h, is the net capacity for outdoor temperature 
tj, calculated as described in section 7.4.2 of AHRI 
1250-2020.
    3.4.12.2 Calculate the AWEF2 as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.073
    
Where:

Ess(tj), in W, is the system power input for temperature 
tj, calculated as described in section 7.4.2 of AHRI 
1250-2020;
Ecu,off, in W, is the condensing unit off-cycle power consumption, 
measured as described in section C3.5 of AHRI 1250-2020; and
nj are the hours for temperature bin j.

3.4.13 High-Temperature Unit Coolers Tested Alone

    3.4.13.1 Calculate Refrigeration System Power Input as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.074
    
Where:

qmix,evap, in W, is the net evaporator capacity, measured as 
described in AHRI 1250-2020;
EFcomp,on, in W, is the unit cooler on-cycle power consumption; and
EER, in W, equals
[GRAPHIC] [TIFF OMITTED] TR04MY23.075

    3.4.13.2 Calculate the load factor LF as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.076
    
Where:

BL, in Btu/h, is the non-equipment-related box load calculated as 
described in section 3.3.3 of this appendix; and
EFcomp,off, in W, is the unit cooler off-cycle power consumption, 
equal to 0.1 times the unit cooler on-cycle power consumption.
    3.4.13.3 Calculate AWEF2 as follows:
    [GRAPHIC] [TIFF OMITTED] TR04MY23.077
    
3.4.14 CO2 Unit Coolers Tested Alone

    Calculate AWEF2 for CO2 Unit Coolers Tested Alone 
using the calculations specified in in section 7.8 of AHRI 1250-2020 
for calculation of AWEF2 for Unit Cooler Tested Alone.

3.5 Test Method

    Test the Refrigeration System in accordance with AHRI 1250-2020 
to determine refrigeration capacity and power input for the 
specified test conditions, with revisions and additions as described 
in this section.

3.5.1 Chamber Conditioning Using the Unit Under Test

    In Appendix C, section C5.2.2 of AHRI 1250-2020, for applicable 
system configurations (matched pairs, single-packaged refrigeration 
systems, and standalone unit coolers), the unit under test may be 
used to aid in achieving the required test chamber conditions prior 
to beginning any steady state test. However, the unit under test 
must be inspected and confirmed to be free from frost before 
initiating steady state testing.

3.5.2 General Modification: Methods of Testing

    3.5.2.1 Refrigerant Temperature Measurements
    When testing a condensing unit alone, measure refrigerant liquid 
temperature leaving the condensing unit, and the refrigerant vapor 
temperature entering the condensing unit as required in section 
C7.5.1.1.2 of Appendix C of AHRI 1250-2020 using the same 
measurement approach specified for the unit cooler in section C3.1.3 
of Appendix C of AHRI 1250-2020. In all cases in which thermometer 
wells or immersed sheathed sensors are prescribed, if the 
refrigerant tube outer diameter is less

[[Page 28867]]

than \1/2\ inch, the refrigerant temperature may be measured using 
the average of two temperature measuring instruments with a minimum 
accuracy of 0.5 [deg]F placed on opposite sides of the 
refrigerant tube surface--resulting in a total of up to 8 
temperature measurement devices used for the DX Dual Instrumentation 
method. In this case, the refrigerant tube shall be insulated with 
1-inch thick insulation from a point 6 inches upstream of the 
measurement location to a point 6 inches downstream of the 
measurement location. Also, to comply with this requirement, the 
unit cooler/evaporator entering measurement location may be moved to 
a location 6 inches upstream of the expansion device and, when 
testing a condensing unit alone, the entering and leaving 
measurement locations may be moved to locations 6 inches from the 
respective service valves.
    3.5.2.2 Mass Flow Meter Location
    When using the DX Dual Instrumentation test method of AHRI 1250-
2020, applicable for unit coolers, dedicated condensing units, and 
matched pairs, the second mass flow meter may be installed in the 
suction line as shown in Figure C1 of AHRI 1250-2020.
    3.5.2.3 Subcooling at Refrigerant Mass Flow Meter
    In section C3.4.5 of Appendix C of AHRI 1250-2020, when 
verifying subcooling at the mass flow meters, only the sight glass 
and a temperature sensor located on the tube surface under the 
insulation are required. Subcooling shall be verified to be within 
the 3 [deg]F requirement downstream of flow meters located in the 
same chamber as a condensing unit under test and upstream of flow 
meters located in the same chamber as a unit cooler under test, 
rather than always downstream as indicated in AHRI 1250-2009, 
section C3.4.5. If the subcooling is less than 3 [deg]F when testing 
a unit cooler, dedicated condensing unit, or matched pair (not a 
single-packaged system), cool the line between the condensing unit 
outlet and this location to achieve the required subcooling. When 
providing such cooling while testing a matched pair (a) set up the 
line-cooling system and also set up apparatus to heat the liquid 
line between the mass flow meters and the unit cooler, (b) when the 
system has achieved steady state without activation of the heating 
and cooling systems, measure the liquid temperature entering the 
expansion valve for a period of at least 30 minutes, (c) activate 
the cooling system to provide the required subcooling at the mass 
flow meters, (d) if necessary, apply heat such that the temperature 
entering the expansion valve is within 0.5 [deg]F of the temperature 
measured during step (b), and (e) proceed with measurements once 
condition (d) has been verified.
    3.5.2.4 Installation Instructions
    Manufacturer installation instructions or installation 
instructions described in this section refer to the instructions 
that come packaged with or appear on the labels applied to the unit. 
This does not include online manuals.
    Installation Instruction Hierarchy: If a given installation 
instruction provided on the label(s) applied to the unit conflicts 
with the installation instructions that are shipped with the unit, 
the label takes precedence. For testing of matched pairs, the 
installation instructions for the dedicated condensing unit shall 
take precedence. Setup shall be in accordance with the field 
installation instructions (laboratory installation instructions 
shall not be used). Achieving test conditions shall always take 
precedence over installation instructions.
    3.5.2.5. Refrigerant Charging and Adjustment of Superheat and 
Subcooling.
    All dedicated condensing systems (dedicated condensing units 
tested alone, matched pairs, and single packaged dedicated systems) 
that use flooding of the condenser for head pressure control during 
low-ambient-temperature conditions shall be charged, and superheat 
and/or subcooling shall be set, at Refrigeration C test conditions 
unless otherwise specified in the installation instructions.
    If after being charged at Refrigeration C condition the unit 
under test does not operate at the Refrigeration A condition due to 
high pressure cut out, refrigerant shall be removed in increments of 
4 ounces or 5 percent of the test unit's receiver capacity, 
whichever quantity is larger, until the unit operates at the 
Refrigeration A condition. All tests shall be run at this final 
refrigerant charge. If less than 0 [deg]F of subcooling is measured 
for the refrigerant leaving the condensing unit when testing at B or 
C condition, calculate the refrigerant-enthalpy-based capacity 
(i.e., when using the DX dual instrumentation, the DX calibrated 
box, or single-packaged unit refrigerant enthalpy method) assuming 
that the refrigerant is at saturated liquid conditions at the 
condensing unit exit.
    All dedicated condensing systems that do not use a flooded 
condenser design shall be charged at Refrigeration A test conditions 
unless otherwise specified in the installation instructions.
    If the installation instructions give a specified range for 
superheat, sub-cooling, or refrigerant pressure, the average of the 
range shall be used as the refrigerant charging parameter target and 
the test condition tolerance shall be 50 percent of the 
range. Perform charging of near-azeotropic and zeotropic 
refrigerants only with refrigerant in the liquid state. Once the 
correct refrigerant charge is determined, all tests shall run until 
completion without further modification.
    3.5.2.5.1. When charging or adjusting superheat/subcooling, use 
all pertinent instructions contained in the installation 
instructions to achieve charging parameters within the tolerances. 
However, in the event of conflicting charging information between 
installation instructions, follow the installation instruction 
hierarchy listed in section 3.5.2.4. Conflicting information is 
defined as multiple conditions given for charge adjustment where all 
conditions specified cannot be met. In the event of conflicting 
information within the same set of charging instructions (e.g., the 
installation instructions shipped with the dedicated condensing 
unit), follow the hierarchy in Table 19 for priority. Unless the 
installation instructions specify a different charging tolerance, 
the tolerances identified in table 19 of this appendix shall be 
used.

Table 19--Test Condition Tolerances and Hierarchy for Refrigerant Charging and Setting of Refrigerant Conditions
----------------------------------------------------------------------------------------------------------------
                                    Fixed orifice                                   Expansion Valve
               -------------------------------------------------------------------------------------------------
   Priority         Parameter with                                       Parameter with
                     installation                Tolerance                installation            Tolerance
                  instruction target                                   instruction target
----------------------------------------------------------------------------------------------------------------
1.............  Superheat............  2.0 [deg]F.......  Subcooling..........  10% of the Target
                                                                                             Value; No less than
                                                                                             0.5
                                                                                             [deg]F, No more
                                                                                             than 2.0 [deg]F
2.............  High Side Pressure or  4.0 psi or 4.0 psi
                 Saturation             minus>1.0 [deg]F.              or Saturation         or
                 Temperature*.                                         Temperature*.        1.0
                                                                                             [deg]F
3.............  Low Side Pressure or   2.0 psi or 2.0
                 Saturation             minus>0.8 [deg]F.                                    [deg]F
                 Temperature*.
4.............  Low Side Temperature.  2.0 [deg]F.......  Low Side Pressure or  2.0 psi
                                                                       Saturation            or
                                                                       Temperature *.       0.8
                                                                                             [deg]F
5.............  High Side Temperature  2.0 [deg]F.......  Approach Temperature  1.0
                                                                                             [deg]F
6.............  Charge Weight........  2.0 oz...........  Charge Weight.......  0.5% or 1.0 oz,
                                                                                             whichever is
                                                                                             greater
----------------------------------------------------------------------------------------------------------------
* Saturation temperature can refer to either bubble or dew point calculated based on a measured pressure, or a
  coil temperature measurement, as specified by the installation instructions.


[[Page 28868]]

    3.5.2.5.2. Dedicated Condensing Unit.
    If the Dedicated Condensing Unit includes a receiver and the 
subcooling target leaving the condensing unit provided in 
installation instructions cannot be met without fully filling the 
receiver, the subcooling target shall be ignored. Likewise, if the 
Dedicated Condensing unit does not include a receiver and the 
subcooling target leaving the condensing unit cannot be met without 
the unit cycling off on high pressure, the subcooling target can be 
ignored. Also, if no instructions for charging or for setting 
subcooling leaving the condensing unit are provided in the 
installation instructions, the refrigeration system shall be set up 
with a charge quantity and/or exit subcooling such that the unit 
operates during testing without shutdown (e.g., on a high-pressure 
switch) and operation of the unit is otherwise consistent with the 
requirements of the test procedure of this appendix and the 
installation instructions.
    3.5.2.5.3. Unit Cooler. Use the shipped expansion device for 
testing. Otherwise, use the expansion device specified in the 
installation instructions. If the installation instructions specify 
multiple options for the expansion device, any specified expansion 
device may be used. The supplied expansion device shall be adjusted 
until either the superheat target is met, or the device reaches the 
end of its adjustable range. In the event the device reaches the end 
of its adjustable range and the super heat target is not met, test 
with the adjustment at the end of its range providing the closest 
match to the superheat target, and the test condition tolerance for 
super heat target shall be ignored. The measured superheat is not 
subject to a test operating tolerance. However, if the evaporator 
exit condition is used to determine capacity using the DX dual 
instrumentation method or the refrigerant enthalpy method, 
individual superheat value measurements may not be equal to or less 
than zero. If this occurs, or if the operating tolerances of 
measurements affected by expansion device fluctuation are exceeded, 
the expansion device shall be replaced, operated at an average 
superheat value higher than the target, or both, in order to avoid 
individual superheat value measurements less than zero and/or to 
meet the required operating tolerances.
    3.5.2.5.4. Single-Packaged Unit. Unless otherwise directed by 
the installation instructions, install one or more refrigerant line 
pressure gauges during the setup of the unit, located depending on 
the parameters used to verify or set charge, as described in this 
section:
    3.5.2.5.4.1. Install a pressure gauge in the liquid line if 
charging is on the basis of subcooling, or high side pressure or 
corresponding saturation or dew point temperature.
    3.5.2.5.4.2. Install a pressure gauge in the suction line if 
charging is on the basis of superheat, or low side pressure or 
corresponding saturation or dew point temperature. Install this 
gauge as close to the evaporator as allowable by the installation 
instructions and the physical constraints of the unit. Use methods 
for installing pressure gauge(s) at the required location(s) as 
indicated in the installation instructions if specified.
    3.5.2.5.4.3. If the installation instructions indicate that 
refrigerant line pressure gauges should not be installed and the 
unit fails to operate due to high-pressure or low-pressure 
compressor cut off, then a charging port shall be installed, and the 
unit shall be evacuated of refrigerant and charged to the nameplate 
charge.
    3.5.2.6 Ducted Units
    For systems with ducted evaporator air, or that can be installed 
with or without ducted evaporator air: Connect ductwork on both the 
inlet and outlet connections and determine external static pressure 
(ESP) as described in sections 6.4 and 6.5 of ANSI/ASHRAE 37. Use 
pressure measurement instrumentation as described in section 5.3.2 
of ANSI/ASHRAE 37. Test at the fan speed specified in the 
installation instructions--if there is more than one fan speed 
setting and the installation instructions do not specify which speed 
to use, test at the highest speed. Conduct tests with the ESP equal 
to 50% of the maximum ESP allowed in the installation instructions, 
within a tolerance of -0.00/+0.05 inches of water column. If the 
installation instructions do not provide the maximum ESP, the ESP 
shall be set for testing such that the air volume rate is \2/3\ of 
the air volume rate measured when the ESP is 0.00 inches of water 
column within a tolerance of -0.00/+0.05 inches of water column.
    If testing using either the indoor or outdoor air enthalpy 
method to measure the air volume rate, adjust the airflow 
measurement apparatus fan to set the external static pressure--
otherwise, set the external static pressure by symmetrically 
restricting the outlet of the test duct. In case of conflict, these 
requirements for setting airflow take precedence over airflow values 
specified in manufacturer installation instructions or product 
literature.
    3.5.2.7. Two-Speed or Multiple-Speed Evaporator Fans. Two-Speed 
or Multiple-Speed evaporator fans shall be considered to meet the 
qualifying control requirements of section C4.2 of Appendix C of 
AHRI 1250-2020 for measuring off-cycle fan energy if they use a fan 
speed no less than 50% of the speed used in the maximum capacity 
tests.
    3.5.2.8. Defrost
    Use section C10.2.1 of Appendix C of AHRI 1250-2020 for defrost 
testing. The Test Room Conditioning Equipment requirement of section 
C10.2.1.1 of Appendix C of AHRI 1250-2020 does not apply.
    3.5.2.8.1 Adaptive Defrost
    When testing to certify compliance to the energy conservation 
standards, use NDF = 4, as instructed in section 
C10.2.1.7 or C10.2.2.1 of AHRI 1250-2020. When determining the 
represented value of the calculated benefit for the inclusion of 
adaptive defrost, use NDF = 2.5, as instructed in section 
C10.2.1.7 or C10.2.2.1 of AHRI 1250-2020.
    3.5.2.8.2 Hot Gas Defrost
    When testing to certify compliance to the energy conservation 
standards, remove the hot gas defrost mechanical components and 
disconnect all such components from electrical power. Test the units 
as if they are electric defrost units, but do not conduct the 
defrost tests described in section C10.2.1 of AHRI 1250-2020. Use 
the defrost heat and power consumption values as described in 
section C10.2.2 of AHRI 1250-2020 for the AWEF2 calculations.
    3.5.2.9 Dedicated condensing units that are not matched for 
testing and are not single-packaged dedicated systems.
    The temperature measurement requirements of sections C3.1.3 and 
C4.1.3.1 appendix C of AHRI 1250-2020 shall apply only to the 
condensing unit exit rather than to the unit cooler inlet and 
outlet, and they shall be applied for two measurements when using 
the DX Dual Instrumentation test method.
    3.5.2.10. Single-packaged dedicated systems
    Use the test method in section C9 of appendix C of AHRI 1250-
2020 (including the applicable provisions of ASHRAE 16-2016, ASHRAE 
23.1-2010, ASHRAE 37-2009, and ASHRAE 41.6-2014, as referenced in 
section C9.1 of AHRI 1250-2020) as the method of test for single-
packaged dedicated systems, with modifications as described in this 
section. Use two test methods listed in table 20 of this appendix to 
calculate the net capacity and power consumption. The test method 
listed with a lower ``Hierarchy Number'' and that has ``Primary'' as 
an allowable use in table 20 of this appendix shall be considered 
the primary measurement and used as the net capacity.

         Table 20--Single-Packaged Methods of Test and Hierarchy
------------------------------------------------------------------------
      Hierarchy number           Method of test        Test hierarchy
------------------------------------------------------------------------
1...........................  Balanced Ambient      Primary.
                               Indoor Calorimeter.
2...........................  Indoor Air Enthalpy.  Primary or
                                                     Secondary.
3...........................  Indoor Room           Primary or
                               Calorimeter.          Secondary.
4...........................  Calibrated Box......  Primary or
                                                     Secondary.
5...........................  Balanced Ambient      Secondary.
                               Outdoor Calorimeter.
6...........................  Outdoor Air Enthalpy  Secondary.
7...........................  Outdoor Room          Secondary.
                               Calorimeter.
8...........................  Single-Packaged       Secondary.
                               Refrigerant
                               Enthalpy \1\.

[[Page 28869]]

 
9...........................  Compressor            Secondary.
                               Calibration.
------------------------------------------------------------------------
Notes:
\1\ See description of the single-packaged refrigerant enthalpy method
  in section 3.5.2.10.1 of this appendix.

    3.5.2.10.1 Single-Packaged Refrigerant Enthalpy Method
    The single-packaged refrigerant enthalpy method shall follow the 
test procedure of the DX Calibrated Box method in AHRI 1250-2020, 
appendix C, section C8 for refrigerant-side measurements with the 
following modifications:
    3.5.2.10.1.1 Air-side measurements shall follow the requirements 
of the primary single-packaged method listed in table 20 of this 
appendix. The air-side measurements and refrigerant-side 
measurements shall be collected over the same intervals.
    3.5.2.10.1.2 A preliminary test at Test Rating Condition A is 
required using the primary method prior to any modification 
necessary to install the refrigerant-side measuring instruments. 
Install surface mount temperature sensors on the evaporator and 
condenser coils at locations not affected by liquid subcooling or 
vapor superheat (i.e., near the midpoint of the coil at a return 
bend), entering and leaving the compressor, and entering the 
expansion device. These temperature sensors shall be included in the 
regularly recorded data.
    3.5.2.10.1.3 After the preliminary test is completed, the 
refrigerant shall be removed from the equipment and the refrigerant-
side measuring instruments shall be installed. The equipment shall 
then be evacuated and recharged with refrigerant. Once the equipment 
is operating at Test Condition A, the refrigerant charge shall be 
adjusted until, as compared to the average values from the 
preliminary test, the following conditions are achieved:
    (a) Each on-coil temperature sensor indicates a reading that is 
within 1.0 [deg]F of the measurement in the initial 
test,
    (b) The temperatures of the refrigerant entering and leaving the 
compressor are within 4 [deg]F, and
    (c) The refrigerant temperature entering the expansion device is 
within 1 [deg]F.
    3.5.2.10.1.4 Once these conditions have been achieved over an 
interval of at least 10 minutes, refrigerant charging equipment 
shall be removed and the official tests shall be conducted.
    3.5.2.10.1.5 The lengths of liquid line to be added shall be 5 
feet maximum, not including the requisite flow meter. This maximum 
length applies to each circuit separately.
    3.5.2.10.1.6 Use section C9.2 of appendix C of AHRI 1250-2020 
for allowable refrigeration capacity heat balance. Calculate the 
single-packaged refrigerant enthalpy (secondary) method test net 
capacity

Qnet,secondary as follows: Qnet,secondary = Qref-
3.412[middot]EFcomp,on-Qsploss

Where:

Qref is the gross capacity;
EFcomp,on is the evaporator compartment on-cycle power, including 
evaporator fan power; and
Qsploss is a duct loss calculation applied to the evaporator 
compartment of the single-packaged systems, which is calculated as 
indicated in the following equation.

Qsploss = UAcond x (Tevapside - Tcondside) + UAamb x (Tevapside - 
Tamb)

Where:
    UAcond and UAamb are, for the condenser/
evaporator partition and the evaporator compartment walls exposed to 
ambient air, respectively, the product of the overall heat transfer 
coefficient and surface area of the unit as manufactured, i.e. 
without external insulation that might have been added during the 
test. The areas shall be calculated based on measurements, and the 
thermal resistance values shall be based on insulation thickness and 
insulation material;
    Tevapside is the air temperature in the evaporator 
compartment--the measured evaporator air inlet temperature may be 
used;
    Tcondside is the air temperature in the condenser 
compartment--the measured chamber ambient temperature may be used, 
or a measurement may be made using a temperature sensor placed 
inside the condenser box at least 6 inches distant from any part of 
the refrigeration system; and
    Tamb is the air temperature outside the single-
packaged system.

    3.5.2.10.1.7 For multi-circuit single-packaged systems utilizing 
the single-packaged refrigerant enthalpy method, apply the test 
method separately for each circuit and sum the separately-calculated 
refrigerant-side gross refrigeration capacities.
    3.5.2.10.2 Calibrated Box Test Procedure
    3.5.2.10.2.1 Measurements. Refer to section C3 of AHRI 1250-2020 
(including the applicable provisions of ASHRAE 41.1-2013, ASHRAE 
41.3-2014, and ASHRAE 41.10-2013, as referenced in section C3 of 
AHRI 1250-2020) for requirements of air-side and refrigerant-side 
measurements.
    3.5.2.10.2.2 Apparatus setup for Calibrated Box Calibration and 
Test. Refer to section C5 of AHRI 1250-2020 and section C8 of AHRI 
1250-2020 for specific test setup.
    3.5.2.10.2.3 The calibrated box shall be installed in a 
temperature-controlled enclosure in which the temperature can be 
maintained at a constant level. When using the calibrated box method 
for Single-Packaged Dedicated Systems, the enclosure air temperature 
shall be maintained such that the condenser air entering conditions 
are as specified for the test.
    3.5.2.10.2. The temperature-controlled enclosure shall be of a 
size that will provide clearances of not less than 18 in at all 
sides, top and bottom, except that clearance of any one surface may 
be reduced to not less than 5.5 inches.
    3.5.2.10.2.5 The heat leakage of the calibrated box shall be 
noted in the test report.
    3.5.2.10.2.6 Refrigerant lines within the calibrated box shall 
be well insulated to avoid appreciable heat loss or gain.
    3.5.2.10.2.7 Instruments for measuring the temperature around 
the outside of the calibrated box to represent the enclosure 
temperature Ten shall be located at the center of each 
wall, ceiling, and floor. Exception: in the case where a clearance 
around the outside of the calibrated box, as indicated in section 
3.5.2.10.2.4 of this appendix, is reduced to less than 18 inches, 
the number of temperature measuring devices on the outside of that 
surface shall be increased to six, which shall be treated as a 
single temperature to be averaged with the temperature of each of 
the other five surfaces. The six temperature measuring instruments 
shall be located at the center of six rectangular sections of equal 
area. If the refrigeration system is mounted at the location that 
would cover the center of the face on which it is mounted, up to 
four temperature measurements shall be used on that face to 
represent its temperature. Each sensor shall be aligned with the 
center of the face's nearest outer edge and centered on the distance 
between that edge and the single-packaged unit (this is illustrated 
in figure C5 of this section when using surface temperature 
sensors), and they shall be treated as a single temperature to be 
averaged with the temperature of each of the other five surfaces. 
However, any of these sensors shall be omitted if either (a) the 
distance between the outer edge and the single-packaged unit is less 
than one foot or (b) if the sensor location would be within two feet 
of any of the foot square surfaces discussed in section 3.5.2.10.2.8 
of this appendix representing a warm discharge air impingement area. 
In this case, the remaining sensors shall be used to represent the 
average temperature for the surface.
    3.5.2.10.2.8 One of the following two approaches shall be used 
for the box external temperature measurement. Box calibration and 
system capacity measurement shall both be done using the same one of 
these approaches. 1: Air temperature sensors. Each temperature 
sensor shall be at a distance of 6 inches from the calibrated box. 
If the clearance from a surface of the box (allowed for one surface 
only) is less than 12 inches, the temperature measuring instruments 
shall be located midway between the outer wall of the calibrated box 
and the adjacent surface. 2: Surface temperature sensors. Surface 
temperature sensors shall be mounted on the calibrated box surfaces 
to represent the enclosure temperature, Ten.
    3.5.2.10.2.9 Additional surface temperature sensors may be used 
to measure external hot spots during refrigeration system

[[Page 28870]]

testing. If this is done, two temperature sensors shall be used to 
measure the average temperature of the calibrated box surface 
covered by the condensing section--they shall be located centered on 
equal-area rectangles comprising the covered calibrated box surface 
whose common sides span the short dimension of this surface. 
Additional surface temperature sensors may be used to measure box 
surfaces on which warm condenser discharge air impinges. A pattern 
of square surfaces measuring one foot square shall be mapped out to 
represent the hot spot upon which the warm condenser air impinges. 
One temperature sensor shall be used to measure surface temperature 
at the center of each square (see figure C5 of this section). A 
drawing showing this pattern and identifying the surface temperature 
sensors shall be provided in the test report. The average surface 
temperature of the overall calibrated box outer surface during 
testing shall be calculated as follows.
[GRAPHIC] [TIFF OMITTED] TR04MY23.078

Where:

Ai is the surface area of the ith of the six calibrated box 
surfaces;
Ti is the average temperature measured for the ith surface;
Aj is half of the surface area of the calibrated box covered by the 
condensing section;
T'j is the jth of the two temperature measurements underneath the 
condensing section;
T1 is the average temperature of the four or fewer measurements 
representing the temperature of the face on which the single-
packaged system is mounted, prior to adjustments associated with hot 
spots based on measurements Tj and/or Tk;
Ak is the area of the kth of n 1-square-foot surfaces used to 
measure the condenser discharge impingement area hot spot; and,
T''k is the kth of the n temperature measurements of the condenser 
discharge impingement area hot spot.
[GRAPHIC] [TIFF OMITTED] TR04MY23.079

Figure C5: Illustration of Layout of Surface Temperature Sensors on 
Face of Calibrated Box on which Single-Packaged Dedicated System is 
Mounted when Using Section 3.5.2.10.2.7 of Appendix C to this 
Part.3.5.2.10.2.10 Heating means inside the calibrated box shall be 
shielded or installed in a manner to avoid radiation to the Single-
Packaged Dedicated System, the temperature measuring instruments, 
and to the walls of the box. The heating means shall be constructed 
to avoid stratification of temperature, and suitable means shall be 
provided for distributing the temperature uniformly.

    3.5.2.10.2.11 The average air dry-bulb temperature in the 
calibrated box during Single-Packaged Dedicated System tests and 
calibrated box heat leakage tests shall be the average of eight 
temperatures measured at the corners of the box at a distance of 2 
inches to 4 inches from the walls. The instruments shall be shielded 
from any cold or warm surfaces except that they shall not be 
shielded from the adjacent walls of the box. The Single-Packaged 
Dedicated System under test shall be mounted such that the

[[Page 28871]]

temperature instruments are not in the direct air stream from the 
discharge of the Single-Packaged Dedicated System.
    3.5.2.10.2.12 Calibration of the Calibrated Box. Calibration of 
the Calibrated Box shall occur prior to installation of the Single-
Packaged Dedicated System. This shall be done either (a) prior to 
cutting the opening needed to install the Single-Packaged Dedicated 
System, or (b) with an insulating panel with the same thickness and 
thermal resistance as the box wall installed in the opening intended 
for the Single-Packaged Dedicated System installation. Care shall be 
taken to avoid thermal shorts in the location of the opening either 
during calibration or during subsequent installation of the Single-
Packaged Dedicated System. A calibration test shall be made for air 
movements comparable to those expected for Single-Packaged Dedicated 
System capacity measurement, i.e., with air volume flow rate within 
10 percent of the air volume flow rate of the Single-Packaged 
Dedicated System evaporator.
    3.5.2.10.2.13 The heat input shall be adjusted to maintain an 
average box temperature not less than 25.0 [deg]F above the test 
enclosure temperature.
    3.5.2.10.2.14 The average dry-bulb temperature inside the 
calibrated box shall not vary more than 1.0 [deg]F over the course 
of the calibration test.
    3.5.2.10.2.15 A calibration test shall be the average of 11 
consecutive hourly readings when the box has reached a steady-state 
temperature condition.
    3.5.2.10.2.16 The box temperature shall be the average of all 
readings after a steady-state temperature condition has been 
reached.
    3.5.2.10.2.17 The calibrated box has reached a steady-state 
temperature condition when: The average box temperature is not less 
than 25 [deg]F above the test enclosure temperature. Temperature 
variations do not exceed 5.0 [deg]F between temperature measuring 
stations. Temperatures do not vary by more than 2 [deg]F at any one 
temperature- measuring station.
    3.5.2.10.2.18 Data to be Measured and Recorded. Refer to Table 
C5 in section C6.2 of AHRI 1250-2020 for the required data that need 
to measured and recorded.
    3.5.2.10.2.19 Refrigeration Capacity Calculation.
    The heat leakage coefficient of the calibrated box is calculated 
by
[GRAPHIC] [TIFF OMITTED] TR04MY23.080

    For each Dry Rating Condition, calculate the Net Capacity:

qss = Kcb (Ten-Tcb) + 3.412 x Ec

    3.5.2.10.3 Detachable single-packaged systems shall be tested as 
single-packaged dedicated refrigeration systems.
    3.5.2.11 Variable-Capacity and Multiple-Capacity Dedicated 
Condensing Refrigeration Systems
    3.5.2.11.1 Manufacturer-Provided Equipment Overrides
    Where needed, the manufacturer must provide a means for 
overriding the controls of the test unit so that the compressor(s) 
operates at the specified speed or capacity and the indoor blower 
operates at the speed consistent with the compressor operating level 
as would occur without override.
    3.5.2.11.2 Compressor Operating Levels
    For variable-capacity and multiple-capacity compressor systems, 
the minimum capacity for testing shall be the minimum capacity that 
the system control would operate the compressor in normal operation. 
Likewise, the maximum capacity for testing shall be the maximum 
capacity that the system control would operate the compressor in 
normal operation. For variable-speed compressor systems, the 
intermediate speed for testing shall be the average of the minimum 
and maximum speeds. For digital compressor systems, the intermediate 
duty cycle shall be the average of the minimum and maximum duty 
cycles. For multiple-capacity compressor systems with three capacity 
levels, the intermediate operating level for testing shall be the 
middle capacity level. For multiple-capacity compressor systems with 
more than three capacity levels, the intermediate operating level 
for testing shall be the level whose displacement ratio is closest 
to the average of the maximum and minimum displacement ratios.
    3.5.2.11.3 Refrigeration Systems with Digital Compressor(s)
    Use the test methods described in section 3.5.2.10.1 of this 
appendix as the secondary method of test for refrigeration systems 
with digital compressor(s) with modifications as described in this 
section. The Test Operating tolerance for refrigerant mass flow rate 
and suction pressure in Table 2 of AHRI 1250-2020 shall be ignored. 
Temperature and pressure measurements used to calculate shall be 
recorded at a frequency of once per second or faster and based on 
average values measured over the 30-minute test period.
    3.5.2.11.3.1 For Matched pair (not including single-packaged 
systems) and Dedicated Condensing Unit refrigeration systems, the 
preliminary test in sections 3.5.2.10.1.2 and 3.5.2.10.1.3 of this 
appendix is not required. The liquid line and suction line shall be 
25 feet  3 inches, not including the requisite flow 
meters. Also, the term in the equation to calculate net capacity 
shall be set equal to zero.
    3.5.2.11.3.2 For Dedicated Condensing Unit refrigeration 
systems, the primary capacity measurement method shall be balanced 
ambient outdoor calorimeter, outdoor air enthalpy, or outdoor room 
calorimeter.

[FR Doc. 2023-08128 Filed 5-3-23; 8:45 am]
BILLING CODE 6450-01-P