[Federal Register Volume 82, Number 141 (Tuesday, July 25, 2017)]
[Proposed Rules]
[Pages 34427-34449]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-15580]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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 

  Federal Register / Vol. 82, No. 141 / Tuesday, July 25, 2017 / 
Proposed Rules  

[[Page 34427]]



DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2017-BT-TP-0018]
RIN 1904-AD93


Energy Conservation Program for Certain Commercial and Industrial 
Equipment: Test Procedure for Certain Categories of Commercial Air 
Conditioning and Heating Equipment

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 
Energy (DOE).

ACTION: Request for information (RFI).

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SUMMARY: In response to statutory requirements to review its test 
procedures in response to any updates of the relevant industry test 
procedures, as referenced in the American Society of Heating, 
Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1 
(ASHRAE Standard 90.1), the U.S. Department of Energy (DOE) is 
initiating a data collection process to consider amendments to DOE's 
test procedures for commercial package air conditioning and heating 
equipment with test procedure updates included in ASHRAE Standard 90.1-
2016--specifically, those evaporatively-cooled commercial unitary air 
conditioners (ECUACs), water-cooled commercial unitary air conditioners 
(WCUACs), and air-cooled commercial unitary air conditioners (ACUACs) 
which have a rated cooling capacity greater than or equal to 65,000 
Btu/h and less than 760,000 Btu/h; and all classes of computer room air 
conditioners (CRACs); as well as to consider adopting a new test 
procedure for dedicated outdoor air systems (DOASes), equipment covered 
by ASHRAE Standard 90.1 for the first time. In response to other 
statutory requirements for DOE to review its test procedures at least 
once every seven years, DOE is also reviewing its test procedures for 
ECUACs and WCUACs with a rated cooling capacity less than 65,000 Btu/h, 
as well as all classes of variable refrigerant flow multi-split air 
conditioners and heat pumps (VRF multi-split systems) but excluding 
single-phase systems with a rated cooling capacity less than 65,000 
Btu/h, which are covered as consumer products. To inform interested 
parties and to facilitate this process, DOE has gathered data and has 
identified several issues that might warrant modifications to the 
currently applicable Federal test procedures, topics on which DOE is 
particularly interested in receiving comment. In overview, the issues 
outlined in this document mainly concern incorporation by reference of 
the most recent version of the relevant industry standard(s); 
efficiency metrics and calculations; clarification of test methods; and 
any additional topics that may inform DOE's decisions in a future test 
procedure rulemaking, including methods to reduce regulatory burden 
while ensuring the procedures' accuracy. These topics (and others 
identified by commenters) are ones which may be addressed in proposed 
test procedure amendments in a subsequent notice of proposed rulemaking 
(NOPR). DOE welcomes written comments and data from the public on any 
subject related to the test procedures for this equipment, including 
topics not specifically raised in this RFI.

DATES: Written comments, data, and information are requested and will 
be accepted on or before August 24, 2017.

ADDRESSES: Interested persons are encouraged to submit comments using 
the Federal eRulemaking Portal at https://www.regulations.gov. Follow 
the instructions for submitting comments. Alternatively, interested 
persons may submit comments, identified by docket number EERE-2017-BT-
TP-0018, by any of the following methods:
     Federal eRulemaking Portal: www.regulations.gov. Follow 
the instructions for submitting comments.
     Email: [email protected]. Include 
EERE-2017-BT-TP-0018 in the subject line of the message.
     Postal Mail: Appliance and Equipment Standards Program, 
U.S. Department of Energy, Building Technologies Office, Mailstop EE-
5B, Test Procedure RFI for Commercial Package Air Conditioning and 
Heating Equipment, Docket No. EERE-2017-BT-TP-0018 and/or RIN 1904-
AD93, 1000 Independence Avenue SW., Washington, DC 20585-0121. If 
possible, please submit all items on a compact disc (CD), in which case 
it is not necessary to include printed copies.
     Hand Delivery/Courier: Appliance and Equipment Standards 
Program, U.S. Department of Energy, Building Technologies Office, 950 
L'Enfant Plaza, SW., 6th Floor, Washington, DC 20024. Telephone: (202) 
586-6636. If possible, please submit all items on a CD, in which case 
it is not necessary to include printed copies.
    No telefacsimilies (faxes) will be accepted. For detailed 
instructions on submitting comments and additional information on the 
rulemaking process, see section III of this document (Public 
Participation).
    Docket: The docket for this activity, which includes Federal 
Register notices, comments, and other supporting document/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 
information that is exempt from public disclosure.
    The docket Web page can be found at: https://www.regulations.gov/docket?D=EERE-2017-BT-TP-0018. The docket Web page will contain simple 
instructions on how to access all documents, including public comments, 
in the docket. See section III of this document, Public Participation, 
for information on how to submit comments through www.regulations.gov.

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. Eric Stas, U.S. Department of Energy, Office of the General 
Counsel, GC-33, 1000 Independence Avenue SW., Washington, DC 20585. 
Telephone: (202) 586-9507. Email: [email protected].
    For further information on how to submit a comment, or review other 
public comments and the docket,

[[Page 34428]]

contact the Appliance and Equipment Standards Program staff at (202) 
586-6636 or by email: [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Authority and Background
II. Discussion
    A. Test Procedure for Computer Room Air Conditioners
    1. Scope
    a. Computer Room Cooling Application
    b. Configurations
    2. Energy Efficiency Descriptor
    a. Integrated Efficiency Metrics
    b. Part-Load Operation Due to Unit Oversizing
    c. Operation Modes Other Than Standard Cooling Mode
    3. Industry Test Standards
    a. Standard Models and Application Classes in AHRI 1360-2016
    b. ASHRAE 37 and Secondary Method
    c. Minimum External Static Pressure
    d. Setting Indoor Airflow
    e. Refrigerant Charging Instruction
    B. Test Procedure for Dedicated Outdoor Air Systems
    1. Definition
    a. Air Intake Source and Dehumidification Capability
    b. Reheat
    2. Energy Efficiency Descriptors
    a. Dehumidification Metric
    b. Heating Metric
    3. Test Method
    a. Airflow
    b. Liquid Flow
    c. Test Conditions
    d. Tolerances
    e. Capacity Measurement
    f. Test Set-Up
    C. Test Procedure for Air-Cooled, Water-Cooled, and 
Evaporatively-Cooled Equipment
    1. Energy Efficiency Descriptor
    2. Addressing Changes to AHRI 340/360
    a. Head Pressure Controls
    b. Refrigerant Charging Requirements
    c. Adjustment for Different Atmospheric Pressure Conditions
    d. Measurement of Condenser Air Inlet Temperature (ACUAC and 
ECUAC)
    e. Tolerance of Tested Indoor Airflow Relative to Rated Indoor 
Airflow (ECUAC and WCUAC)
    f. Vertical Separation of Indoor and Outdoor Units
    g. Outdoor Entering Air Wet-Bulb Temperature (ECUAC)
    h. Single-Zone Variable-Air-Volume and Multi-Zone Variable-Air-
Volume
    3. Additional Test Method Issues
    a. Length of Refrigerant Line Exposed to Outdoor Conditions
    b. Atmospheric Pressure Measurement
    c. Consistency Among Test Procedures for Small and Large ECUAC 
and WCUAC Equipment Classes
    d. Make-Up Water Temperature (ECUAC)
    e. Secondary Measurement Method for Capacity (ECUAC)
    f. Piping Evaporator Condensate to Condenser Pump (ECUAC)
    g. Purge Water Settings (ECUAC)
    h. Condenser Spray Pumps (ECUAC)
    i. Additional Steps To Verify Proper Operation (ECUAC)
    D. Test Procedure for Variable Refrigerant Flow Multi-Split Air 
Conditioners and Heat Pumps
    1. Energy Efficiency Descriptors
    2. Representativeness and Repeatability
    3. Test Method
    a. Transient Testing: Oil Recovery Mode
    b. Airflow Setting and Minimum External Static Pressure
    c. Condenser Head Pressure Controls
    d. Air Volume Rate for Non-Ducted Indoor Units
    e. Secondary Test Method
    f. Heat Recovery
    4. Representations
    a. Tested Combination
    b. Determination of Represented Values
    E. Other Test Procedure Topics
III. Submission of Comments

I. Authority and Background

    Title III, part C \1\ of the Energy Policy and Conservation Act of 
1975 (EPCA or the Act), Public Law 94-163 (42 U.S.C. 6311-6317, as 
codified), added by Public Law 95-619, title IV, section 441(a), 
established the Energy Conservation Program for Certain Industrial 
Equipment, which includes provisions covering the types of commercial 
heating and air conditioning equipment that are the subject of this 
notice.\2\ This covered equipment includes small, large, and very large 
commercial package air conditioning and heating equipment, which 
specifically includes variable refrigerant flow multi-split air 
conditioners and heat pumps (VRF multi-split systems),\3\ computer room 
air conditioners (CRACs), dedicated outdoor air systems (DOASes), 
evaporatively-cooled commercial unitary air conditioners (ECUACs) less 
than 760,000 Btu/h, water-cooled commercial unitary air conditioners 
(WCUACs) less than 760,000 Btu/h, and air-cooled commercial unitary air 
conditioners (ACUACs) greater than or equal to 65,000 Btu/h and less 
than 760,000 Btu/h, all of which are addressed in this document. (42 
U.S.C. 6311(1)(B)-(D))
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    \1\ For editorial reasons, upon codification in the U.S. Code, 
part C was redesignated part A-1.
    \2\ All references to EPCA in this document refer to the statute 
as amended through the Energy Efficiency Improvement Act of 2015, 
Public Law 114-11 (April 30, 2015).
    \3\ Not including single-phase VRF less than 65,000 Btu/h.
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    Under EPCA, the energy conservation program consists essentially of 
four parts: (1) Testing, (2) labeling, (3) Federal energy conservation 
standards, and (4) certification and enforcement procedures. Relevant 
provisions of the Act include definitions (42 U.S.C. 6311), energy 
conservation standards (42 U.S.C. 6313), test procedures (42 U.S.C. 
6314), labeling provisions (42 U.S.C. 6315), and the authority to 
require information and reports from manufacturers (42 U.S.C. 6316).
    Federal energy efficiency requirements for covered equipment 
established under EPCA generally supersede State laws and regulations 
concerning energy conservation testing, labeling, and standards. (See 
42 U.S.C. 6316(a) and (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))
    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 (see 42 U.S.C. 
6316(b); 42 U.S.C. 6296), and (2) making 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.
    Under 42 U.S.C. 6314, EPCA sets forth the general criteria and 
procedures DOE is required to follow when prescribing or amending test 
procedures for covered equipment. EPCA requires that any prescribed or 
amended test procedures must be reasonably designed to produce test 
results which reflect energy efficiency, energy use or estimated annual 
operating cost of a covered equipment during a representative average 
use cycle or period of use and requires that the test procedure not be 
unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))
    EPCA requires that the test procedures for commercial package air 
conditioning and heating equipment be those generally accepted industry 
testing procedures or rating procedures developed or recognized by the 
Air-Conditioning, Heating, and Refrigeration Institute (AHRI) or by the 
American Society of Heating, Refrigerating and Air-Conditioning 
Engineers (ASHRAE), as referenced in ASHRAE Standard 90.1, ``Energy 
Standard for Buildings Except Low-Rise Residential Buildings'' (ASHRAE 
Standard 90.1), and that if such an industry test procedure is amended, 
DOE must update its test procedure to be consistent with the amended 
industry test procedure, unless DOE determines, by rule published in 
the Federal Register and

[[Page 34429]]

supported by clear and convincing evidence, that the amended test 
procedure would not meet the requirements in 42 U.S.C. 6314(a)(2) and 
(3) related to representative use and test burden. (42 U.S.C. 
6314(a)(4))
    ASHRAE Standard 90.1 was updated on October 26, 2016,\4\ and this 
update made changes to the test procedure references in ASHRAE Standard 
90.1-2013 for CRACs, as well as ACUACs, ECUACs, and WCUACs with cooling 
capacity >=65,000 Btu/h and <760,000 Btu/h.\5\ Additionally, ASHRAE 
Standard 90.1-2016 added efficiency levels and a test procedure for 
DOAS. These changes on the part of ASHRAE trigger DOE's obligation to 
review these test procedures pursuant to the requirements of EPCA.
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    \4\ There is no publication date printed on ASHRAE Standard 
90.1-2016, but ASHRAE issued a press release on October 26, 2016, 
which can be found at https://www.ashrae.org/news/2016/ashrae-ies-publish-2016-energy-efficiency-standard.
    \5\ For water-source heat pumps, ASHRAE Standard 90.1-2016 
included reference to a reaffirmation of the existing test 
procedure, and as such, does not constitute a change requiring DOE 
action.
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    EPCA also requires that DOE conduct an evaluation of test 
procedures at least once every seven years for each class of covered 
equipment to determine if an amended test procedure would more 
accurately or fully comply with the requirements in 42 U.S.C. 
6314(a)(2) and (3). (42 U.S.C. 6314(a)(1)(A)) After this evaluation, 
DOE must either prescribe amended test procedures or publish a notice 
in the Federal Register regarding its determination not to amend test 
procedures. (42 U.S.C. 6314(a)(1)(A)(i) and (ii)) In either case, if 
DOE determines that a test procedure amendment is warranted, it must 
publish proposed test procedures and offer the public an opportunity to 
present oral and written comments on them. (42 U.S.C. 6314(b)) To amend 
a test procedure, DOE must determine the extent to which the proposed 
test procedure would alter the equipment's measured energy efficiency. 
If DOE determines that the amended test procedure would alter the 
measured efficiency of the covered equipment, DOE must amend the 
applicable energy conservation standard accordingly. (42 U.S.C. 
6314(a)(4)(C); 42 U.S.C. 6293(e))
    Although ASHRAE Standard 90.1-2016 did not include revisions to the 
test procedures for VRF equipment or ECUACs and WCUACs with cooling 
capacity <65,000 Btu/h, DOE is including such equipment in this RFI 
under DOE's 7-year lookback authority. The test procedures under review 
in this RFI are shown in Table I.1.

                Table I.1--Commercial Air Conditioning and Heating Equipment Included in the RFI
----------------------------------------------------------------------------------------------------------------
                                       Review test procedure
                                       due to  amendments to     Last test procedure    7-Year review due (final
      Equipment included in RFI           industry test or          (final rule)                 rule)
                                         rating procedure?
----------------------------------------------------------------------------------------------------------------
CRAC................................  Yes....................  77 FR 28928 (May 16,    May 16, 2019.
                                                                2012).
DOAS................................  Yes....................  N/A...................  N/A.
ECUAC...............................  Yes (>=65,000 Btu/h      77 FR 28928 (May 16,    May 16, 2019.
                                       only*).                  2012).
WCUAC...............................  Yes (>=65,000 Btu/h      77 FR 28928 (May 16,    May 16, 2019.
                                       only*).                  2012).
ACUAC >= 65,000 Btu/h**.............  Yes....................  80 FR 79655 (Dec. 23,   Dec. 23, 2022.
                                                                2015).
VRF (except single-phase <65,000 Btu/ No.....................  77 FR 28928 (May 16,    May 16, 2019.
 h***).                                                         2012).
----------------------------------------------------------------------------------------------------------------
* DOE is considering ECUAC and WCUAC with cooling capacity less than 65,000 Btu/h in this rulemaking notice
  under its 7-year lookback authority.
** DOE will be considering ACUAC with cooling capacity less than 65,000 Btu/h under its 7-year lookback
  authority in a separate test procedure rulemaking.
*** Single-phase VRF with rated cooling capacity less than 65,000 Btu/h are covered under DOE's consumer product
  regulations for central air conditioners.

    Upon completion of this proceeding, DOE expects to satisfy for all 
the equipment categories listed in Table I.1, both the requirements of 
EPCA pertaining to DOE action prompted by amendments to industry test 
or rating procedures, as well as EPCA's 7-year review requirements. In 
support of its test procedures, DOE conducts in-depth technical 
analyses of publicly-available test standards and other relevant 
information. DOE continually seeks data and public input to improve its 
testing methodologies to more accurately reflect customer use and to 
produce repeatable results. In general, DOE is requesting comment and 
supporting data regarding representative and repeatable methods for 
measuring the energy use of the equipment that is the subject of this 
RFI. As such, DOE is interested in feedback on any aspect of the test 
procedures for the identified equipment, but it is especially 
interested in receiving comment and information on the specific topics 
discussed below.

II. Discussion

    This RFI discusses each category of equipment under consideration 
in separate sections set forth below. DOE seeks input to aid in the 
development of the technical and economic analyses regarding whether 
amended test procedures for each category of equipment may be 
warranted. Specifically, DOE is requesting comment on any opportunities 
to streamline and simplify testing requirements for each category of 
equipment discussed in this notice.
    Additionally, DOE welcomes comments on other issues relevant to the 
conduct of this rulemaking that may not specifically be identified in 
this document. In particular, DOE notes that under Executive Order 
13771, ``Reducing Regulation and Controlling Regulatory Costs,'' 
Executive Branch agencies such as DOE are directed to manage the costs 
associated with the imposition of expenditures required to comply with 
Federal regulations. See 82 FR 9339 (Feb. 3, 2017). Pursuant to that 
Executive Order, DOE encourages the public to provide input on measures 
DOE could take to lower the cost of its regulations applicable to the 
commercial equipment addressed in this notice consistent with the 
requirements of EPCA.
    Within each section, DOE raises relevant issues regarding scope, 
efficiency metric, and test method, with a focus on changes identified 
by review of the updated test procedures in ASHRAE Standard 90.1-2016. 
As required by statute, DOE is considering amendments to the current 
test procedures (and in the case of DOAS, adoption of a new test 
procedure) to be consistent with those specified in

[[Page 34430]]

ASHRAE 90.1-2016, where possible. Further, DOE requests comment on the 
benefits and burdens of adopting the industry test procedures 
referenced in ASHRAE 90.1-2016, without modification.

A. Test Procedure for Computer Room Air Conditioners

    DOE's test procedure for CRACs, set forth at 10 CFR 431.96, 
currently incorporates by reference ASHRAE 127-2007, ``Method of 
Testing for Rating Computer and Data Processing Room Unitary Air 
Conditioners'', (omit section 5.11), with additional provisions 
indicated in 10 CFR 431.96(c) and (e). The energy efficiency metric is 
sensible coefficient of performance (SCOP) for all CRAC equipment 
categories. ASHRAE 90.1-2016 updated its test procedure reference for 
CRACs from ASHRAE 127-2007 to AHRI 1360-2016, ``Performance Rating of 
Computer and Data Processing Room Air Conditioners'', which in turn 
references ASHRAE 127-2012. This update on the part of ASHRAE triggered 
DOE to review its test procedure for CRACs. In addition, DOE is aware 
that the ASHRAE 127 committee is working on an updated version of that 
standard, and DOE may consider the updated version when it is 
available.
    In order to ensure that potential adoption of AHRI 1360-2016 as the 
DOE test procedure for CRACs would satisfy statutory requirements, the 
following sections consider issues related to the reduced scope of AHRI 
1360-2016 relative to ASHRAE 127-2007, as well as updates in the 
industry test standards to the test method and rating conditions. DOE 
also explores other CRAC-related issues including definitions and the 
efficiency metric.
1. Scope
a. Computer Room Cooling Application
    The definition for ``computer room air conditioner'' in DOE's 
regulations does not include physical design differences, component 
characteristics, or performance features that distinguish CRACs from 
other commercial package air conditioning and heating equipment (e.g., 
CUACs) used for comfort cooling.\6\ In March 2012, DOE published a 
supplemental notice of proposed rulemaking (SNOPR) refining its 
proposed definition of ``computer room air conditioner.'' 77 FR 16769, 
16772-16773 (March 22, 2012). In response to this SNOPR, several 
stakeholders commented about differences in performance features 
between CRACs and CUACs. Carrier commented that CRACs are designed to 
handle different load characteristics, most notably by focusing on 
sensible load and not latent cooling. (EERE-2011-BT-STD-0029, Carrier, 
No. 28 at p. 1) Panasonic commented that CRACs have a different 
operating range and that they operate with tighter tolerances on 
temperature and relative humidity than do CUACs. (EERE-2011-BT-STD-
0029, Panasonic, No. 20 at pp. 68-69) Despite these comments, DOE was 
unable to determine any specific requirements on sensible load that 
would consistently differentiate CRACs from CUACs and allow it to 
incorporate performance characteristics into the CRAC definition. 
Therefore, on May 16, 2012, DOE adopted the current definition for 
``computer room air conditioner'' that distinguishes them from CUACs 
based on application differences. 77 FR 28928, 28947-28948 (May 16, 
2012; ``May 2012 final rule'').
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    \6\ DOE defines ``computer room air conditioner'' as a basic 
model of commercial package air-conditioning and heating equipment 
(packaged or split) that is: used in computer rooms, data processing 
rooms, or other information technology cooling applications; rated 
for sensible coefficient of performance (SCOP) and tested in 
accordance with 10 CFR 431.96, and is not a covered consumer product 
under 42 U.S.C. 6291(1)-(2) and 6292. A computer room air 
conditioner may be provided with, or have as available options, an 
integrated humidifier, temperature, and/or humidity control of the 
supplied air, and reheating function. 10 CFR 431.92.
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    A review of 1000 CRAC models in DOE's Compliance Certification 
Management System (CCMS) shows that all of these models have a sensible 
heat ratio (SHR) above 80 percent. In contrast, commercial air 
conditioners used for comfort cooling generally have SHRs between 65 
percent and 80 percent. DOE notes that the indoor air test condition 
for CUACs has a higher relative humidity than the test condition for 
CRACs. Therefore, the SHR for any air conditioner will be higher when 
tested using the CRAC test condition than when using the CUAC test 
conditions. However, DOE is considering whether a specific SHR (e.g., 
80 percent at the test condition of CRACs) would be sufficient to 
differentiate CRACs from other CUACs.
    Issue CRAC-1: DOE requests comment on the extent to which models of 
commercial package air conditioners are marketed and/or installed for 
use in both comfort cooling and computer room cooling applications. DOE 
also seeks comment on whether there are models rated for energy 
efficiency ratio (EER) or seasonal energy efficiency ratio (SEER) and 
not SCOP that are used for computer room cooling--if so, DOE requests 
comment and data on the extent of the use of such equipment for 
computer room cooling.
    Issue CRAC-2: DOE seeks comment and data on whether a specific 
sensible heat ratio could be selected that would effectively and 
consistently distinguish CRACs from other classes of commercial package 
air conditioners. DOE also seeks comment on any other design 
differences or performance features that would help resolve this issue.
b. Configurations
    The following sections discuss configurations of CRACs that DOE has 
identified on the market and for which DOE is considering potential 
modifications to its current test procedure.
i. Airflow Direction and Mounting Location
    DOE's minimum efficiency standards for CRACs in 10 CFR 431.97 apply 
to down-flow and up-flow units, which is terminology typically applied 
to floor-mounted units. However, DOE's test procedure for CRACs in 10 
CFR 431.96 is not limited to floor-mounted units. On January 15, 2015, 
DOE published a final guidance document (``January 2015 Guidance 
Document'') to clarify the coverage of horizontal free-discharge CRACs 
under DOE's regulations for CRACs set forth in 10 CFR part 431.\7\ In 
the January 2015 Guidance Document, DOE clarified that while horizontal 
free-discharge CRACs are not subject to the energy conservation 
standards for CRACs, the 2012 test procedure final rule did not have an 
exception for any specific airflow direction (i.e., down-flow, up-flow 
or horizontal-flow) or mounting type (i.e., floor-mount, ceiling-
mount).\8\ Therefore, any manufacturer making representations of the 
energy consumption of CRACs (including ceiling-mounted ducted or free-
discharge units or horizontal free-discharge units and all other 
equipment that meets the CRAC definition) must base these 
representations on tests conducted according to the current DOE test 
procedure. A manufacturer may request a test procedure waiver for a

[[Page 34431]]

basic model if it contains design features that prevent testing 
according to the DOE test procedure, or such testing may generate 
results that are unrepresentative of the true energy consumption of the 
basic model. 10 CFR 431.401. To date, DOE has not received any such 
waiver requests.
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    \7\ The January 2015 Guidance document can be found as Document 
Number 2 in Docket Number EERE-2014-BT-GUID-0022.
    \8\ On October 7, 2015, DOE published a draft guidance document 
(``October 2015 Guidance Document'') seeking comment concerning the 
coverage of ceiling-mount ducted and free-discharge CRACs. (The 
October 2015 Guidance document can be found as Document Number 3 in 
Docket Number EERE-2014-BT-GUID-0022.) DOE has not yet finalized 
this guidance with respect to ceiling-mounted ducted and free-
discharge CRACs. The draft guidance also took the position that such 
CRACs were not subject to standards, but the test procedure did not 
have an exception for any specific airflow direction.
---------------------------------------------------------------------------

    DOE notes that the scope of AHRI Standard 1360-2016 (AHRI 1360-
2016), ``2016 Standard for Performance Rating of Computer and Data 
Processing Room Air Conditioners'', the test procedure referenced in 
ASHRAE 90.1-2016, excludes ceiling-mounted units, only covering floor-
mounted units. As stated in the October 2015 Guidance Document, ASHRAE 
127-2007 can be used to test ceiling-mounted units. DOE understands 
that the ASHRAE 127 committee is considering additional provisions that 
would apply specifically to ceiling-mounted equipment, but a revised 
ASHRAE 127 standard is not yet available. For those CRACs not addressed 
by AHRI 1360-2016, DOE may consider continuing to reference ASHRAE 127-
2007 or updating to a revised version of ASHRAE 127 when published, if 
appropriate.
    Issue CRAC-3: DOE requests comment on the appropriate test 
procedure for ceiling-mounted CRACs, considering that AHRI 1360-2016 
does not address them, and the test burden associated with any such 
procedure.
ii. Three-Phase Portable Units
    Several manufacturers market portable units for commercial use in 
data centers and computer rooms. On June 1, 2016, under its authority 
for regulating consumer products, DOE published a final rule that 
established a test procedure for portable air conditioners. 81 FR 
35242. In addition, DOE issued a final rule to establish energy 
conservation standards for portable air conditioners. In a final 
determination published on April 18, 2016, DOE established a definition 
for ``portable air conditioner'' that excludes units that use three-
phase power as a means of differentiating the portable air conditioners 
that are consumer products (and thus determined to be covered products) 
from those that could normally not be used in residential applications. 
81 FR 22514, 22519-22520. DOE identified several models of portable 
units that are marketed for commercial computer room cooling 
applications and use three-phase power instead of single-phase power. 
This equipment does not meet DOE's definition for ``portable air 
conditioner'' and is not subject to DOE's current test procedures or 
standards for portable air conditioners. DOE considers any portable 
unit marketed for computer room cooling that is rated with SCOP and is 
not a covered consumer product under 42 U.S.C. 6291(1)-(2) and 6292 to 
meet its definition of ``computer room air conditioner.'' DOE is 
considering amendments to its test procedure for computer room air 
conditioners to better reflect usage in the field of portable units 
used for computer room cooling that are not covered consumer products, 
as applicable.
    Issue CRAC-4: DOE requests comments on whether any specific 
provisions should be considered to address how to test portable units 
used in computer room cooling applications, such as whether they are 
typically ducted and, if so, what a representative minimum external 
static pressure (ESP) and return air temperature would be.
iii. Single Package Non-Floor-Mounted Air Conditioners
    DOE identified several manufacturers that produce single package 
non-floor-mounted air conditioners (other than portable units) that are 
marketed specifically for cooling computer rooms, telecommunication 
rooms, and data centers. DOE identified such air conditioners designed 
for both interior and exterior installation. Of the exterior-mount 
units DOE identified, some meet DOE's definition for ``single package 
vertical air conditioner'' (one type of single-package vertical unit 
(SPVU)), while others are rooftop units. All of these identified models 
appear to meet DOE's definition for computer room air conditioners. 
Therefore, DOE is considering whether amendments are needed in its test 
procedure for CRACs to better reflect the in-field energy use and 
installation practices of single-package non-floor-mounted air 
conditioners used for computer room cooling.
    Issue CRAC-5: DOE seeks information on the extent to which single-
package non-floor-mounted air conditioners are used in computer room 
applications.
    Issue CRAC-6: DOE seeks comment on whether special test procedure 
provisions should be developed for different kinds of single package 
non-floor-mounted air conditioners that are used for computer room 
cooling, including: (1) Whether such units are typically installed with 
supply/return air ducting; and (2) whether the test set-up described in 
ANSI/ASHRAE 37-2009, ``Methods of Testing for Rating Electrically 
Driven Unitary Air-Conditioning and Heat Pump Equipment,'' (ASHRAE 37-
2009) is appropriate and if any additional test set-up provisions would 
be needed.
    Issue CRAC-7: DOE requests comment on whether there are other 
configurations of commercial package air conditioners that are marketed 
for computer room cooling applications and that meet DOE's definition 
for CRAC, beyond floor-mounted units (i.e., up-flow, down-flow, and 
horizontal discharge), ceiling-mounted units, portable units, indoor 
single package units, rooftop units, and certain SPVUs.
2. Energy Efficiency Descriptor
    When ASHRAE 90.1-2016 amended its energy efficiency levels, it also 
updated its test procedure from ASHRAE 127-2007 to AHRI 1360-2016. AHRI 
1360-2016 defines standard rating configurations and conditions and 
provides additional requirements for testing CRACs, but does not 
include a method of test. Instead, AHRI 1360-2016 references ASHRAE 
127-2012 as the method of test. This test procedure change also updated 
the ASHRAE 90.1 efficiency metric for CRACs from SCOP to net sensible 
coefficient of performance (NSenCOP). DOE's current efficiency metric 
for CRACs is SCOP. As compared with SCOP, the new metric NSenCOP 
specifies different operating conditions for water-cooled and glycol-
cooled models and adjusts the efficiency to account for the energy use 
associated with the water or glycol pump. These changes presumably 
result in a more accurate representation of the energy use associated 
with the equipment. Because ASHRAE 90.1 changed the metric to NSenCOP, 
EPCA requires that DOE must consider updating to NSenCOP as well. For 
completeness, DOE reviews other issues related to efficiency metrics 
for CRACs in this section, including: (1) Integrated efficiency 
metrics; (2) part-load operation due to unit oversizing; and (3) 
operation modes other than standard cooling mode. If DOE ultimately 
decides to change its metric from SCOP to NSenCOP, DOE would need to 
develop a crosswalk analysis to translate DOE's existing standards--
which are in terms of SCOP--to the NSenCOP metric.
a. Integrated Efficiency Metrics
    ASHRAE 127-2007 includes the integrated efficiency metric, adjusted 
sensible coefficient of performance (ASCOP), which is calculated based 
on the SCOPs at four different rating conditions (A, B, C, and D), 
representing different ambient conditions, with weightings for the SCOP 
at each rating condition based on the climate at a specific location. 
ASHRAE 127-2012 and AHRI 1360-2016 include an updated integrated 
efficiency metric, integrated net sensible coefficient of

[[Page 34432]]

performance iNSenCOP, instead of ASCOP. There are differences between 
ASCOP and iNSenCOP, similar to those between SCOP and NSenCOP, but both 
are weighted averages of sensible-capacity-based efficiencies measured 
for operation at different ambient conditions.
    The ASCOP and iNSenCOP test methods in ASHRAE 127-2007, ASHRAE 127-
2012, and AHRI 1360-2016 require units to maintain a constant sensible 
cooling capacity at lower ambient temperatures. However, it is not 
clear how the lower-ambient tests are to be conducted. As the ambient 
temperature decreases, the maximum cooling capacity of a CRAC will 
inherently increase. ASHRAE 127-2012 does not provide guidance 
regarding how the unit should be controlled in order to deliver the 
same amount of sensible cooling as its capacity increases for the 
lower-ambient tests.
    Issue CRAC-8: DOE requests comment on whether DOE should consider 
adopting an integrated efficiency metric (e.g., iNSenCOP). Also if so, 
DOE requests comment on how the requirement to maintain a constant 
sensible cooling capacity associated with the iNSenCOP test procedure 
should be implemented during testing.
b. Part-Load Operation Due to Unit Oversizing
    CRACs typically operate at part-load (i.e., less than designed full 
cooling capacity) in the field. Reasons for this may include, but are 
not limited to, redundancy in installed units to prevent server 
shutdown if a CRAC unit stops working, and server room designers 
building in extra cooling capacity to accommodate additional server 
racks in the future. At part-load, single-speed systems cycle on and 
off to match the cooling requirement, while variable speed systems 
might operate at a different speed, but both control strategies change 
performance as compared to full-load operation. While the DOE test 
procedure measures performance at full-load, DOE estimated in its May 
2012 final rule analysis that CRAC units operate on average at a 
sensible load of 65 percent of the full-load sensible capacity. (EERE-
2011-BT-STD-0029-0021, pp. 4-15, 4-16). This may indicate a difference 
between DOE test procedure operating requirements and typical field 
operation. Therefore, DOE is considering whether this practice of 
oversizing should be factored into a CRAC efficiency metric to the 
extent that it would better represent an average use cycle.
    Issue CRAC-9: DOE requests information on the range of typical 
field load levels for CRACs at conditions close to or at the maximum 
ambient outdoor air temperature conditions specified in the DOE test 
procedure for various unit capacities. DOE seeks input on typical rules 
of thumb for oversizing and whether the issues of oversizing of this 
equipment should be addressed in the efficiency metric.
c. Operation Modes Other Than Standard Cooling Mode
    Many CRACs operate in air circulation mode. DOE understands that 
redundant units are usually installed in the computer room, and some of 
the redundant units can be controlled to operate in air circulation 
mode for better air movement. In this mode, the direct expansion 
refrigerant system is shut down, and only evaporator blowers and 
controls are on. DOE is considering whether the energy consumption of 
air circulation mode should be considered in the CRAC energy efficiency 
metric.
    Issue CRAC-10: DOE seeks comment on the conditions under which 
CRACs will operate in air circulation mode (i.e., operating the indoor 
fan without actively cooling) in the field, whether each CRAC switches 
automatically between standard cooling mode and air circulation mode, 
and if so, the time percentage that CRACs operate in such circulation 
mode. DOE also seeks comment on what fan setting(s) is used for air 
circulation mode and whether DOE should consider this energy use in the 
CRAC efficiency metric.
3. Industry Test Standards
    In its test procedure for CRACs, DOE currently incorporates by 
reference ASHRAE 127-2007 (omitting section 5.11). 10 CFR 431.96. As 
mentioned previously, ASHRAE published an updated version of this test 
standard in 2012, ASHRAE 127-2012. ASHRAE 127-2012 includes several 
modifications from ASHRAE 127-2007, which are discussed in the 
following sections. DOE is aware that ASHRAE is working to update 
ASHRAE 127-2012, and DOE may consider the newer version of the test 
standard if it is published during the course of this rulemaking. As 
discussed previously, DOE is also aware that the referenced industry 
test procedure in ASHRAE Standard 90.1-2016 has changed to AHRI 1360-
2016. The scope of AHRI 1360-2016 covers only floor-mounted computer 
and data processing room air conditioners, including up-flow, down-
flow, and horizontal-flow units. AHRI 1360-2016 defines standard 
configurations and provides rating conditions and additional 
requirements for testing CRACs, but does not include a method of test. 
Instead, AHRI 1360-2016 references ASHRAE 127-2012 to conduct the test. 
Consequently, DOE will consider adopting both industry test standards. 
In the following sections, DOE discusses specific test procedure-
related issues and questions regarding ASHRAE 127-2012 and AHRI 1360-
2016.
a. Standard Models and Application Classes in AHRI 1360-2016
    Indoor floor-mounted CRACs can be installed in different 
configurations, which vary by direction of airflow and connections 
(e.g., raised floor plenum, ducted, free air). Instead of specifying 
test conditions for all possible combinations, AHRI 1360-2016 includes 
the concept of ``standard models'' that characterize common 
configurations and specify standard rating conditions (e.g., external 
static pressure, return air temperature) for each style of indoor 
floor-mounted CRAC. Table C.1 of Appendix C of AHRI 1360-2016 defines 
four different standard models: (1) Down-flow (with raised floor plenum 
discharge and free air return); (2) horizontal-flow (with free air 
discharge and free air return); (3) up-flow ducted (with ducted 
discharge and free air return); and (4) up-flow non-ducted (with free 
air discharge and free air return). AHRI 1360-2016 also specifies which 
of the four standard model test set-ups and standard rating conditions 
apply for down-flow, horizontal-flow, and up-flow CRACs. For example, 
down-flow units are tested with a raised floor plenum discharge and a 
free air return.
    DOE notes that for up-flow CRACs, AHRI 1360-2016 includes two 
standard models with associated standard rating conditions, one for 
ducted discharge connections and one for free air discharge. However, 
connection variations are characteristics of installations. A given up-
flow unit could be installed either with or without a duct. DOE's 
research has not revealed that up-flow CRACs have physical 
characteristics that clearly distinguish them as ducted or non-ducted 
models. Hence, it is not clear which of the AHRI 1360-2016 up-flow 
standard model requirements would be used for testing.
    Issue CRAC-11: DOE requests comment on what equipment 
characteristics can be used to determine whether up-flow CRACs should 
be tested as ducted or non-ducted models. DOE also requests comments on 
whether up-flow units can be sold for both up-flow ducted and up-flow 
non-ducted applications and whether such

[[Page 34433]]

models are currently tested using both ducted and non-ducted standard 
rating conditions.
    DOE also notes that, in addition to the four standard models of 
floor-mounted CRACs, Table C.1 of AHRI 1360-2016 also includes many 
additional combinations of connections, referred to as application 
configurations, but does not provide standard rating conditions for 
these configurations.
    Issue CRAC-12: DOE requests confirmation that, although floor-
mounted CRACs may be sold to be installed in multiple configurations, 
all models are capable of being tested as one of the four standard 
models identified in Table C.1 of AHRI 1360-2016.
    AHRI 1360-2016 does not include standard models or standard rating 
conditions for ceiling-mount or non-floor mount CRACs. The current DOE 
test procedure, which incorporates by reference ASHRAE 127-2007, 
specifies different test operating conditions (e.g., different external 
static pressure) than AHRI 1360-2016.
    Issue CRAC-13: DOE requests comment on whether the test 
requirements of ASHRAE 127-2007 are representative of average use 
cycles for ceiling-mount and other non-floor-mounted CRACs. If not, DOE 
requests comment on which, if any, of the test requirements of AHRI 
1360-2016 would more appropriately represent average use cycles for 
such CRACs.
b. ASHRAE 37 and Secondary Method
    ASHRAE 127-2007 references ANSI/ASHRAE 37-2005, ``Methods of 
Testing for Rating Unitary Air-Conditioning and Heat Pump Equipment'' 
(ASHRAE 37-2005), while 127-2012 and AHRI 1360-2016 reference the 
updated version, ASHRAE 37-2009. ASHRAE 37-2005 and the updated ASHRAE 
37-2009 describe test methods for measuring cooling capacity, heating 
capacity, and electrical energy use of air conditioners and heat pumps. 
However, it is not clear whether the industry test standards for CRACs 
reference specific provisions or all of the provisions of ASHRAE 37-
2005 or ASHRAE 37-2009.\9\ No alternate methods for determining cooling 
capacity are included in ASHRAE 127 or AHRI 1360. Therefore, DOE 
expects that manufacturers do use the test methods of ASHRAE 37-2005 or 
ASHRAE 37-2009 to determine cooling capacity, sensible cooling 
capacity, and electric energy use of CRACs. DOE is considering updating 
the DOE test procedure to clarify that the test method is based on 
ASHRAE 37-2009, except as modified or adjusted by ASHRAE 127-2012 or 
AHRI 1360-2016.
---------------------------------------------------------------------------

    \9\ For example, in ASHRAE 127-2007, the reference to ASHRAE 37-
2005 is located under a subsection 5.1.4.5.2 titled, ``Raised Floor 
Plenum Systems'' which is located under section 5.1.4.5 titled 
``External Resistance, Ducted Connected, Floor Plenum and Free Air 
Discharge.''
---------------------------------------------------------------------------

    Issue CRAC-14: DOE seeks comment on whether the test method of 
ASHRAE 37-2009 is appropriate for measuring capacity, sensible 
capacity, and electric energy use for all configurations of CRACs 
(including configurations for which DOE does not currently prescribe 
energy conservation standards).
    Table 2b in section 8 of ASHRAE 37-2009 includes test operating 
tolerances (maximum allowable observed range) and condition tolerances 
(maximum variation of the average from a specified test condition) for 
several parameters, including air and fluid temperatures, in order to 
reduce the uncertainty of the measurement of cooling capacity, heating 
capacity, and/or energy use of air conditioners or heat pumps. However, 
this section of ASHRAE 37-2009 is not explicitly referenced by the CRAC 
industry test standards. Section 5.1 of ASHRAE 127-2007 and section 
5.2.1 of ASHRAE 127-2012 only include an operation tolerance for the 
room temperature, and no versions of ASHRAE 127 or AHRI 1360 include 
any other tolerances. DOE considers the tolerances of Table 2b of 
ASHRAE 37-2009 to be relevant for CRACs and important to reduce 
variability of key CRAC performance measurements.
    Issue CRAC-15: DOE requests comment on whether any operating or 
condition tolerances included in Table 2b in section 8 of ASHRAE 37-
2009 are not appropriate for CRACs. If any are not appropriate, DOE 
requests an explanation as to why and suggestions on how the tolerances 
should be changed.
    Section 7.2.1 of ASHRAE 37-2009 requires that when testing 
equipment with a total cooling capacity less than 135,000 Btu/h, 
simultaneous capacity tests using the indoor air enthalpy method and 
one other applicable method must be conducted. Specifically, these 
other test methods include the outdoor air enthalpy method, the 
compressor calibration method, the refrigerant enthalpy method, and the 
outdoor liquid coil method. Table 1 in section 7 of ASHRAE 37-2009 
specifies which of these test methods are applicable for each equipment 
configuration and method of heat rejection in cooling mode. Section 
10.1.2 of ASHRAE 37-2009 requires that the total cooling capacity 
calculated from the two simultaneously conducted methods agree within 
6.0 percent.
    For CRACs with cooling capacity less than 135,000 Btu/h, DOE is 
considering whether its test procedure should require a secondary test 
method and how agreement between the primary and secondary methods 
should be evaluated. DOE is also considering whether the primary and 
secondary tests should be based on total cooling capacity or sensible 
cooling capacity. Basing these tests on sensible cooling capacity may 
be more appropriate because it is the basis of the CRAC efficiency 
metric in both ASHRAE Standard 90.1 and the current Federal standard.
    Issue CRAC-16: DOE seeks comment on whether a secondary test is 
appropriate for testing CRACs, for what range of cooling capacity such 
a requirement should apply for CRACs, how the requirement should be 
applied (given that most secondary test methods measure total rather 
than sensible capacity), and what level of agreement (in percent) 
should be required. DOE is also interested in detailed information on 
whether there would be a significant additional test burden resulting 
from a secondary test--and if so, the nature and extent of that burden.
    Many CRACs have compressors housed in their indoor units. ASHRAE 
37-2009 specifies modification of the indoor enthalpy method as 
depicted in its Figure 3, Calorimeter air enthalpy test method 
arrangement, for capturing the impact of compressor heat on the 
capacity measurement. However, none of the industry test standards 
explicitly call for using this test set-up for CRAC indoor units to 
take into consideration the cooling capacity reduction associated with 
compressor heat.
    Issue CRAC-17: DOE requests comment on whether it is appropriate to 
incorporate the impact of compressor heat in sensible capacity 
measurements for CRACs with compressors housed in their indoor units. 
DOE requests that the comments provide an explanation as to why it is 
or is not appropriate, and whether the answer depends on the specific 
CRAC configuration.
c. Minimum External Static Pressure
    ASHRAE 127-2007, ASHRAE 127-2012, and AHRI 1360-2016 all contain 
different minimum external static pressure (ESP) levels and categories, 
as indicated in Table II.1. In ASHRAE 127-2012, the minimum ESP levels 
are the same as for ASHRAE 127-2007, but ASHRAE 127-2012 defines 
``ducted systems'' as ``air conditioners intended to be connected to 
supply and/or return ductwork'' instead of ``to supply and return 
ductwork,'' as specified in ASHRAE 127-2007.

[[Page 34434]]



            Table II.1--External Static Pressure Requirements
------------------------------------------------------------------------
                                                            Minimum ESP
         Test standard                CRAC Category         (in. w.c.)
------------------------------------------------------------------------
ASHRAE 127-2007 and ASHRAE 127-  Ducted:                  ..............
 2012.                           Net Sensible Capacity <             0.8
                                  20 kW.                             1.0
                                 Net Sensible Capacity
                                  >= 20 kW.
                                 Free Discharge.........             0.0
AHRI 1360-2016.................  Up-flow Ducted:
                                 Net Sensible Capacity               0.3
                                  <65 kBtu/h.
                                 Net Sensible Capacity               0.4
                                  >=65 kBtu/h and <240
                                  kBtu/h.
                                 Net Sensible Capacity               0.5
                                  >=240 kBtu/h and <769
                                  kBtu/h.
                                 Horizontal and Up-flow              0.0
                                  Non-ducted.
                                 Down-flow..............             0.2
------------------------------------------------------------------------

    DOE is considering the test procedures and the ESP levels of AHRI 
1360-2016, but seeks input on the significant difference in the ESP 
values of the different test standards. Additionally, AHRI 1360-2016 
does not include minimum ESP requirements for ceiling-mounted units. 
AHRI-1360-2016 also made very significant changes to the ESPs for up-
flow ducted and down-flow configurations compared to ASHRAE 127-2012. 
DOE received no data or information from ASHRAE indicating the 
rationale for the changes or why lower static pressures are more 
representative of field performance. Thus, DOE is particularly 
interested in any information regarding the static pressures that are 
likely representative of all CRACs.
    Issue CRAC-18: DOE requests comment on whether the ESP levels 
required by AHRI 1360-2016 are representative of field operation for 
floor-mounted CRACs.
    Issue CRAC-19: DOE requests information on whether the ESP levels 
required by ASHRAE 127-2012 are representative of field operation for 
ceiling-mounted CRACs and for other non-floor-mounted CRAC 
configurations, and if not, what a representative minimum ESP would be.
    DOE's review of CRAC installation manuals suggests that some up-
flow units are installed with a plenum box that redirects the airflow 
from the upwards direction to the front or rear.
    Issue CRAC-20: DOE requests comment on the percentage of up-flow 
CRAC installations in which a plenum box that redirects air from the 
upward direction to the front or rear would be attached, and whether 
non-ducted units are tested with or without this plenum.
    DOE identified several models of air-cooled CRACs that have an 
indoor condenser and, therefore, may require ducting of condenser air. 
Neither AHRI 1360-2016 nor ASHRAE 127-2013 address the possibility of 
condenser ducting, and accordingly, would call for testing such CRACs 
like others in free-inlet and free-discharge mode. However, this might 
not be representative of field operation. The condenser fan for a CRAC 
with a ducted condenser has to overcome the additional pressure drop of 
the ducts; thus, imposing a minimum ESP requirement for testing may 
better reflect field operating conditions than testing the unit with 
free air inlet and discharge. However, this could require attaching an 
apparatus to allow adjustment of ESP, which would add to test burden. 
Alternatively, if a well-defined air duct set-up for indoor condensers 
could be developed (e.g., specific length and cross-sectional 
dimensions for the inlet and/or outlet air duct), a standardized 
airflow resistance could be imposed without requiring a similar 
connection and adjustment of the airflow and measurement apparatus as 
used for measurement of indoor airflow, which could significantly 
reduce test burden.
    Issue CRAC-21: DOE seeks comment on how to set up the condenser air 
flow when testing CRACs manufactured with condenser air inlet and 
outlet connections and high-static condenser fans, which indicate that 
such units can be installed indoors with the condenser air ducted to 
and from the outdoors. Additionally, DOE requests comment on whether 
some CRACs can be installed with or without condenser ducting, and if 
so, how often these units are typically installed with condenser 
ducting. DOE also seeks comment on whether certain CRAC configurations 
are more likely to be installed with condenser ducting.
d. Setting Indoor Airflow
    DOE currently requires manufacturers to certify the indoor airflow 
for CRACs. However, DOE's test procedure and industry test standards do 
not impose tolerances on achieving the certified airflow and/or the 
minimum ESP during testing. The performance of any air conditioner can 
be significantly affected by operation with indoor airflow that is very 
different from the intended airflow.
    For ACUACs with capacity >=65,000 Btu/h, DOE established a 
requirement that the full-load indoor airflow rate must be within 
3 percent of the certified airflow. 80 FR 79655, 79671 
(Dec. 23, 2015; ``December 2015 CUAC TP final rule''). Tolerance for 
ESP in this test is -0.00/+0.05 in. w.c. In contrast, for consumer 
central air conditioners and heat pumps (CAC/HPs), the method for 
setting indoor air volume rate for ducted units without variable-speed 
constant-air-volume-rate indoor fans is a multi-step process that 
addresses the discrete-step fan speed control of these units. In this 
method, (a) the air volume rate during testing may not be higher than 
the certified air volume rate, but may be 10 percent less, and (b) the 
ESP during testing may not be lower than the minimum specified ESP, but 
may be higher than the minimum if this is required to avoid having the 
air volume rate overshoot its certified value. 81 FR 36992, 37026 (June 
8, 2016; ``June 2016 CAC TP final rule'').
    Issue CRAC-22: DOE seeks information on how certified airflow is 
achieved in laboratory testing of CRACs, both with indoor blowers that 
are continuously variable and for indoor blowers that are adjustable in 
discrete steps. DOE also seeks comments on whether the tolerances for 
setting airflow of commercial CUACs or of CAC/HPs are appropriate for 
CRACs, and what tolerances would be appropriate for airflow and ESP.
e. Refrigerant Charging Instruction
    Neither the ASHRAE nor the AHRI testing standards for CRACs include 
specific instructions for refrigerant charging. The June 2016 CAC TP 
final rule provides a comprehensive approach for charging intended to 
improve test reproducibility. The approach indicates which set of 
installation instructions to use for charging, explains what to do if 
there are no instructions, indicates that target values of parameters 
are the centers of the ranges allowed by installation

[[Page 34435]]

instructions, and specifies tolerances for the measured values. 81 FR 
36992, 37030-37031. An approach that details methods such as these 
could improve the CRAC test method.
    Issue CRAC-23: DOE requests comments on what refrigerant charging 
requirements should be considered to establish reproducible test 
results for CRACs, and whether the approach developed for CAC/HP 
products may be appropriate. Also, DOE seeks comments on the typical 
operating conditions at which the unit is charged in the field and/or 
what conditions should be used to set refrigerant charge for testing 
purposes.
    Issue CRAC-24: DOE requests comments on any other issues related to 
the adoption of AHRI 1360-2016 as the test procedure for CRACs.

B. Test Procedure for Dedicated Outdoor Air Systems

    DOASes appear to meet the EPCA definition for ``commercial package 
air conditioning and heating equipment,'' \10\ and could be considered 
as a category of that covered equipment. (42 U.S.C. 6311(8)(A)) 
However, DOE has tentatively concluded that if DOASes are a category of 
``commercial package air conditioning and heating equipment,'' there 
are no existing DOE test procedures or energy conservation standards 
for that category of commercial package air conditioning and heating 
equipment. Specifically, DOE does not believe that DOAS are among the 
commercial ``central air conditioners and central air conditioning heat 
pumps'' for which EPCA originally established standards (42 U.S.C. 
6313(a)(1)-(2), (7)-(9)), and for which the current test procedure and 
standards are codified in Table 1 to 10 CFR 431.96 and Tables 1-4 of 10 
CFR 431.97 (as air conditioners and heat pumps).
---------------------------------------------------------------------------

    \10\ Under the statute, ``commercial package air conditioning 
and heating equipment'' means air-cooled, water-cooled, 
evaporatively-cooled, or water-source (not including ground-water-
source) electrically operated, unitary central air conditioners and 
central air conditioning heat pumps for commercial application.
---------------------------------------------------------------------------

    Neither EPCA nor DOE defines commercial ``central air conditioners 
and central air conditioning heat pumps.'' DOASes operate similarly to 
commercial central air conditioners and central air conditioning heat 
pumps, in that they provide space conditioning using a refrigeration 
cycle consisting of a compressor, condenser, expansion valve, and 
evaporator. However, DOASes are designed to provide 100 percent outdoor 
air to the conditioned space, while outdoor air makes up only a small 
portion of the total airflow for typical commercial air conditioners, 
usually less than 50 percent. When operating in humid conditions, the 
dehumidification load is a much larger percentage of total cooling load 
for a DOAS than for a typical commercial air conditioner. Additionally, 
compared to a typical commercial air conditioner, the amount of total 
cooling (both sensible and latent) is much greater per pound of air for 
a DOAS at design conditions (i.e., the warmest/most humid expected 
summer conditions), and a DOAS is designed to accommodate greater 
variation in entering air temperature and humidity. DOASes are 
typically installed in addition to a primary cooling system (e.g., 
CUAC, VRF, chilled water system, water-source heat pumps)--the DOAS 
conditions the outdoor ventilation air, while the primary system 
provides cooling to balance building shell and interior loads and solar 
heat gain. DOE is considering whether there is a need for definitions 
of ``commercial central air conditioners and central air conditioning 
heat pumps'' and ``dedicated outdoor air systems'' to clarify this 
distinction. If DOE determines this necessary, it would do so through a 
future rulemaking proceeding.
    ASHRAE 90.1-2016 created separate equipment classes for DOAS units 
and set minimum efficiency levels using the integrated seasonal 
moisture removal efficiency (ISMRE) metric for all DOAS classes and the 
integrated seasonal coefficient of performance (ISCOP) metric for air-
source heat pump and water-source heat pump DOAS classes. Both metrics 
are measured in accordance with AHRI Standard 920-2015, ``Performance 
Rating of DX-Dedicated Outdoor Air System Units'' (AHRI 920-2015). AHRI 
920-2015 references ASHRAE Standard 198-2013, ``Method of Test for 
Rating DX-Dedicated Outdoor Air Systems for Moisture Removal Capacity 
and Moisture Removal Efficiency'' (ASHRAE 198-2013), as the method of 
test for DOAS units.
    DOE must adopt the industry standard designated by ASHRAE 90.1 
unless it is not consistent with EPCA requirements. Accordingly, DOE is 
considering the test methods of AHRI 920-2015 and ASHRAE 198-2013, but 
may consider modifications of these test methods if necessary to 
fulfill the EPCA requirements. In the following sections, DOE reviews 
potential definitions and efficiency metrics for DOAS, as well as 
questions regarding the test method in the industry standards.
1. Definition
    As stated previously, DOE is considering how to define ``dedicated 
outdoor air system.'' Both AHRI 920-2015 and ASHRAE 198-2013 include 
definitions for DOAS. DOE may adopt one of these definitions, but it 
may also adjust the definition to assure that it is clear and complete. 
The following sections address different aspects of the definitions 
provided in the industry test standards.
a. Air Intake Source and Dehumidification Capability
    Both AHRI 920-2015 and ASHRAE 198-2013 define a DOAS as a product 
that dehumidifies 100-percent outdoor air to a low dew point. However, 
section 6.6 of ASHRAE 198-2013 provides requirements for dampers not 
used for introducing outdoor air, suggesting that some DOAS units take 
in some percentage of return air. Accordingly, DOE has identified 
models from multiple manufacturers that are advertised as DOASes, but 
which incorporate a damper-controlled return air inlet that allows 
return air to be mixed with outdoor air.
    CUACs also often incorporate a damper to mix return air and outdoor 
air. Additionally, CUACs also can dehumidify 100-percent outdoor air, 
although generally not to a dew point as low as DOASes. Hence, DOE is 
concerned that the dehumidification capability and/or the range of 
percentage of return air flow may have to be quantified to distinguish 
DOASes and CUACs.
    Issue DOAS-1: DOE requests information on the range of the maximum 
percentage of return air intake relative to total air flow of DOAS 
models in order to determine whether the maximum return air percentage 
is an important DOAS distinguishing feature.
    Issue DOAS-2: DOE requests comment on the differences in 
dehumidification capabilities of CUACs and DOASes when operating with 
100-percent outdoor air. Specifically, DOE seeks comment on whether a 
difference can be quantified to be a clear differentiating feature of 
DOASes--for example, can a specific dew point criterion for a given set 
of outdoor air conditions be established that can be achieved by any 
DOAS, but that no conventional CUAC can achieve?
b. Reheat
    DOE is interested in determining how the ability to reheat 
dehumidified air should be incorporated into the definition of a DOAS. 
The AHRI 920-2015 definition requires that a DOAS

[[Page 34436]]

include reheat ``capable of controlling the supply dry-bulb temperature 
of the dehumidified air to the designed supply air temperature,'' 
whereas the ASHRAE 198-2013 definition indicates only that DOASes may 
have this functionality. The ASHRAE 198-2013 definition indicates that 
the DOAS might also have a supplemental heat system ``for use when 
outdoor air requires heating beyond the capability of the refrigeration 
system and/or other heat transfer apparatus.'' Supplemental heating is 
also mentioned in the note below the AHRI 920-2015 definition.
    Issue DOAS-3: DOE requests comment on whether and how reheating 
functionality should be included in the DOAS definition. If reheat 
should be required for a unit to be considered a DOAS, DOE requests 
comment on whether a minimum reheat capacity should be specified in the 
definition. DOE also requests information to clarify the difference 
between a reheat system and a supplementary heat system in a DOAS--for 
example, if reheat is required for a DOAS, can it be a supplementary 
reheat system (i.e., one that uses a heat source other than warm 
refrigerant or heat recovered from the return air)?
2. Energy Efficiency Descriptors
a. Dehumidification Metric
    ISMRE is a seasonal efficiency metric calculated based on moisture 
removal efficiency (MRE) at four different dehumidification rating 
conditions. The weighted values are derived from bin hour data (i.e., 
temperature/humidity data for a selection of representative cities 
indicating the number of hours of occurrence of each ``bin'' 
representing a defined range of temperature and humidity) to represent 
seasonal operation. MRE is calculated as moisture removal capacity 
(MRC) divided by the total energy input, as described in ASHRAE 198-
2013 section 10.6.
    DOE is seeking clarification on the calculation procedure for 
ISMRE. ASHRAE 198-2013 indicates measuring MRE twice for each test 
condition, once with reheat on and once with reheat off. AHRI 920-2015 
does not specify which of these values of MRE is used in the 
calculation of ISMRE. AHRI 920-2015 section 6.1.3.1 calls for a 
supplemental heat penalty if the supply air temperature is less than 70 
[deg]F, but the incorporation of this penalty into the MRE equation is 
not clearly described. It is also not clear whether the ASHRAE 198-2013 
test method considers this penalty. Finally, the equation for the 
supplemental heat penalty in AHRI 920-2015 appears to be missing the 
supply air volume flow rate as a factor.
    Issue DOAS-4: DOE requests information to clarify the calculation 
procedure for ISMRE. Specifically, DOE requests input on which 
dehumidification test MRE should be used (and why), how and when the 
supplementary heat penalty is applied, and the basis for the 
supplementary heat equation.
    While the primary functions of DOASes are to provide ventilation 
and to dehumidify the outdoor air, the units also provide sensible 
cooling to the supplied air stream. However, the sensible cooling 
provided by the unit is not accounted for as part of the MRE or ISMRE 
efficiency metric. DOE is aware that the total sensible cooling 
provided may be significantly less than the latent cooling associated 
with removal of moisture--for example, conditions C and D of Tables 2 
and 3 of AHRI 1360-2016 specify inlet air conditions already cooler 
than the target 70 [deg]F supply temperature--but sensible cooling may 
be important enough to consider for the warmer test conditions.
    Issue DOAS-5: DOE requests comment on whether the DOAS efficiency 
metric should also account for sensible cooling provided for 
ventilation air during the cooling/dehumidification season.
    The ISMRE metric is based on testing at four different operating 
conditions, involving specification of both dry bulb and wet bulb 
outdoor temperature. A weighted average of the MRE measurements 
determined for the four conditions is calculated to obtain ISMRE. DOE 
test procedures must provide a measurement that is representative of an 
average use cycle for the tested equipment. (42 U.S.C. 6314(a)(2)) 
Among the considerations that might be relevant in defining the test 
conditions and weighting factors is the fact that ventilation air must 
be delivered to occupied spaces during occupied hours, which would put 
more emphasis on daytime hours for development of the metric.
    Issue DOAS-6: DOE seeks information about analysis of climate data 
relevant to the development of the ISMRE test conditions and weighting 
factors in order to confirm that the metric provides a measurement that 
is representative of an average use cycle for DOAS equipment.
b. Heating Metric
    ISCOP is a seasonal energy efficiency descriptor calculated as the 
weighted average of heating COP determined for two different heating 
rating conditions. DOE test procedures must provide a measurement that 
is representative of an average use cycle for the tested equipment. (42 
U.S.C. 6314(a)(2)) Section 6.4 of AHRI 920-2015 indicates that the 
weighting factors for the COPs are derived from bin hour data to 
represent a full year of operation.
    Issue DOAS-7: DOE seeks information about analysis of climate data 
relevant to the development of the ISCOP test conditions and weighting 
factors in order to allow confirmation that the metric provides a 
measurement that is representative of an average use cycle for DOAS 
heat pump equipment.
    ``Integrated seasonal coefficient of performance,'' as defined in 
AHRI 920-2015, is an energy efficiency metric for water-source heat 
pumps. However, DOE notes that ASHRAE 90.1-2016 includes ISCOP minimum 
efficiency levels for air-source heat pumps (heating mode) in Table 
6.8.1-16 in addition to water-source heat pumps. ASHRAE 198-2013 
section 10.9 claims that its equations for calculating COP are for 
water-source heat pumps, although the COP definition in ASHRAE 198-2013 
does not exclude air-source heat pumps, and the equations should apply 
equally well for air-source heat pumps. Finally, DOE notes that tests 
conducted at 35 [deg]F dry bulb temperature for consumer central air 
conditioning heat pumps (which are air-source) consider the impacts of 
defrosting of the outdoor coil in the energy use measurement (see 
section 3.9 of 10 CFR part 430, subpart B, appendix M), while defrost 
is not discussed at all in ASHRAE 198-2013. Defrost has a real impact 
on efficiency because of energy use associated with defrost and because 
a system cannot continue to provide heating during defrost operation, 
thereby reducing time-averaged capacity. Hence, consideration of 
defrost could provide a more field-representative measurement of 
performance.
    Issue DOAS-8: DOE seeks input on the calculation procedure for the 
COP of air-source heat pump DOASes, including whether testing for test 
condition E of AHRI 920-2015 Table 2 (35 [deg]F dry bulb/29 [deg]F wet 
bulb) should consider energy use associated with defrost.
    The COP equation of ASHRAE 198-2013 section 10.9 uses the term 
qhp to represent the heating capacity in the COP 
calculation. This term does not appear in the nomenclature section, but 
the subscript ``hp'' suggests that this includes only heat provided by 
the heat pumping function of the DOAS unit. However, the equation 
defining qhp is based on supply air temperature, suggesting 
that any of the possible

[[Page 34437]]

additional methods for providing heat (e.g., supplemental heat, heat 
recovery) may contribute to qhp and thereby boost COP by 
increasing the numerator of the COP equation. The COP equation includes 
only electric power input in the denominator and does not include 
energy use that might be associated with fuel-fired supplemental heat. 
In addition, the supplemental heat penalty of AHRI 920-2015 section 
6.1.3.1, which the section states applies to the heating test 
conditions as well as the dehumidification test conditions, seems to 
penalize the COP calculation excessively, because it does not indicate 
that the additional heating should be added to the qhp of 
the COP equation.
    Issue DOAS-9: DOE seeks input on the calculation for COP and how 
the supplemental heat penalty is included. DOE also seeks input on how 
the heating capacity and power/fuel consumption of various supplemental 
heating sources are accounted for as part of the COP equation and how 
DOAS manufacturers incorporate the impacts of these sources in their 
ISCOP calculations.
3. Test Method
a. Airflow
i. Supply Airflow
    Section 5.2.2 of AHRI 920-2015 specifies instructions regarding 
supply airflow rate. Section 5.2.2.1 of that industry standard requires 
either use of the supply airflow that occurs at the minimum external 
static pressure of Table 4 or a manufacturer-specified lower leaving 
airflow rate that occurs with higher external static pressure. Section 
5.2.2.3 of that industry standard further requires that the 
manufacturer specify a single airflow for all tests. However, many DOAS 
systems can operate over a range of airflow rates, and DOE expects that 
their indoor fans can be set up with a range of speeds to accommodate 
the airflow range and the variation in duct length in field 
installations. Further, some DOAS systems are employed for demand 
ventilation use, for which reduced airflow will likely be required for 
a significant portion of the unit's use. Such systems also are likely 
to have variable-speed indoor fans, whose speed settings for the test 
may also have to be defined clearly. The performance of the DOAS may 
vary significantly from the low end to the high end of the rated 
installation airflow range. DOE is concerned that the selected airflow 
rate may not provide a representative indication of field use, and that 
there may not be sufficient clarity regarding how to set up for testing 
a unit with multiple indoor fan speed options.
    Issue DOAS-10: DOE requests input on the appropriate selection of 
the supply airflow rate for testing units that can operate with a range 
of airflow rates. DOE requests information regarding how manufacturers 
select the airflow rate for testing and any data demonstrating the 
variation of DOAS unit performance over a range of installed airflow 
rates.
    Issue DOAS-11: DOE requests comment on whether it would be 
appropriate to develop a test that includes part-load (reduced 
ventilation air) test points to quantify the efficiency benefit of 
demand-controlled ventilation for DOASes that are capable of operating 
with this control.
ii. Return Airflow
    For testing DOAS units with energy recovery,\11\ Tables 2 and 3 in 
AHRI 920-2015 provide return airflow temperature conditions and 
indicate that they apply to units with energy recovery at balanced 
airflow (i.e., tested with supply airflow equal to exhaust airflow). It 
is unclear what airflow streams should be balanced, how to determine if 
they are balanced, and within what tolerances they should be balanced. 
DOE is considering clarifying the return airflow set-up procedures.
---------------------------------------------------------------------------

    \11\ DOAS units with energy recovery take in and discharge 
exhaust air, using a device such as an energy recovery wheel that 
can transfer heat and moisture from the exhaust air to the outdoor 
air, thereby preconditioning the outdoor air and reducing the load 
required to cool, dehumidify, or heat the air to the desired supply 
conditions.
---------------------------------------------------------------------------

    Issue DOAS-12: DOE requests comment regarding how manufacturers who 
have tested heat recovery DOAS set up return airflow for testing DOAS 
units with energy recovery as prescribed by the AHRI 920-2015 test 
standard. Further, DOE requests comment on whether balanced airflow is 
representative of field installation, and what ESP levels should be set 
up for the return airflow.
iii. Exhaust Air Transfer Ratio
    Exhaust air transfer ratio (EATR) is an indicator of the amount of 
air that leaks from the return air side of the energy recovery wheel to 
the supply air side. Such leakage could increase the apparent 
dehumidification provided by a DOAS unit because the return air is less 
humid than the outdoor air into which the return air could leak--thus, 
high leakage could boost the ISMRE rating without providing any real 
benefit. However, DOE recognizes that such leakage may be low enough in 
most energy recovery wheels that the EATR measurement would represent 
an unnecessary addition to test burden.
    Issue DOAS-13: DOE seeks comments on whether EATR should be 
included in DOE's test procedure for DOAS, and, if so, how it should be 
used in determining DOAS ratings. DOE requests information on the range 
of return air leakage typical for energy recovery wheels used in 
DOASes.
b. Liquid Flow
i. Water Flow Rate for Water-Source DOASes
    Neither AHRI 920-2015 nor ASHRAE 198-2013 provides requirements for 
outlet water temperature or water flow rate for water-cooled units. 
Instead, AHRI 920-2015 specifies a standard rating test water entering 
temperature in Table 2 and requires in section 6.1.4.3 that the 
manufacturer specify a water flow rate, unless it is controlled 
automatically by the device. However, ANSI/AHRI 340/360-2007 with 
addenda 1 and 2, ``Standard for Performance Rating of Commercial and 
Industrial Unitary Air-Conditioning and Heat Pump Equipment'' (AHRI 
340/360-2007) and ANSI/AHRI 210/240-2008 with addenda 1 and 2, 
``Standard for Performance Rating of Unitary Air-Conditioning & Air-
Source Heat Pump Equipment'' (AHRI 210/240-2008), which cover 
performance rating for water-cooled commercial air-conditioning 
equipment, employ a different method. Both of these standards specify 
water inlet and outlet temperatures for the standard rating conditions, 
rather than relying on manufacturers to determine water flow rate. 
Further, both standards specify that the full-load water flow rate 
determined for the standard rating conditions should also be used for 
IEER part-load rating conditions. DOE believes that these approaches to 
testing reflect the typical design temperature differential for cooling 
towers serving water-cooled equipment, and a very common approach for 
control of condenser water pumps, and hence it is not clear why the 
same approach would not be adopted for water-cooled DOAS.
    Issue DOAS-14: DOE requests information on how condenser water flow 
rates are set in the field and how they are controlled at part load. 
DOE also requests comment on whether the provisions of section 6.1.4.3 
of AHRI 920-2015 provide sufficient guidance regarding how to set up 
water flow for DOASes with automatic water flow control systems.

[[Page 34438]]

ii. Energy Consumption of Pumps and Fans for Water-Source Condensers
    AHRI 920-2015 offers Equation 1 for calculating the total pump 
effect (PE), an estimate of the energy consumption of non-integral 
water pumps (i.e., pumps that are not part of the DOAS unit and whose 
power consumption would, therefore, not already be part of the measured 
power). Section 6.1.3 of AHRI 920-2015 implies that this calculation 
applies solely to water pumps serving refrigerant-to-liquid heat 
recovery devices--no indication is given whether the equation also 
applies for pumps serving water-source or water-cooled condensers--
although it is possible that the term ``refrigerant-to-liquid heat 
recovery device'' refers to the condenser of a water-source heat pump 
DOAS. Further, neither AHRI 920-2015 nor ASHRAE 198-2013 mention 
accounting for the energy consumption of heat recovery fans for water 
loops or water-cooled condensers. In contrast, AHRI 340/360-2007, which 
is used for rating water-cooled CUACs, provides in section 6.1 a power 
consumption allowance for both the cooling tower fan and the 
circulating water pump.
    Issue DOAS-15: DOE requests confirmation that the ``refrigerant-to-
liquid heat recovery device'' cited in section 6.1.3 of AHRI 920-2015 
is intended to include heat exchangers used for rejection of 
refrigerant circuit heat during the dehumidification cycle, and comment 
on whether Equation 1 of this section for estimating the energy usage 
of water pumps is appropriate for DOASes with water-cooled condensers.
    Issue DOAS-16: DOE requests comment on accounting for the energy 
consumption for heat-rejection fans employed in water-cooled or water-
loop DOASes.
iii. Energy Consumption for the Chiller System for Liquid-Cooled DOAS 
Using Chilled Water for Condenser Cooling
    One of the options for testing water-cooled DOAS is to provide 
condenser cooling water at 45 [deg]F, replicating operation in which 
condenser cooling is provided by a chilled water system. When operating 
in this fashion, the chilled water system must expend additional energy 
to maintain the 45 [deg]F supply water condition--it is not clear that 
this energy is considered in the ISMRE metric. Without this energy use 
contribution, the ratings for such equipment would appear to be have an 
unfair advantage in comparison to the ratings for DOAS rated using 
cooling tower water. The minimum efficiency levels in ASHRAE 90.1-2016 
for both equipment classes certainly do reflect this advantage, with 
the ISMRE levels being 4.9 for water-cooled DOAS using cooling tower 
water and 6.0 for those using chilled water. Although the 6.0 ISMRE 
level for chilled-water-cooled operation appears to be much more 
efficient, it does not include the energy use associated with the 
chiller system required to deliver the chilled water at the specified 
45 [deg]F.
    Issue DOAS-17: DOE requests comment on whether energy contributions 
should be considered for the chiller system of a water-cooled DOAS that 
is rated for use with chilled water for condenser cooling. If so, DOE 
requests comment on the appropriate representative value for the 
chiller system energy contribution.
c. Test Conditions
i. Supply Air Conditions
    AHRI 920-2015 includes a requirement of minimum supply air 
temperature of 70.0 [deg]F for all standard rating conditions and a 
maximum dew-point temperature of 55.0 [deg]F for standard rating 
conditions for dehumidification. ASHRAE 198-2013 requires a supply air 
temperature of 75.2 [deg]F or as close to this value as the controls 
will allow during testing.
    Issue DOAS-18: DOE requests comment or clarification related to the 
difference in target supply air temperature requirements between AHRI 
920-2015 and ASHRAE 198-2013. DOE requests comments as to the 
appropriate supply air temperature for use in the DOE test procedure 
for DOAS.
ii. Cooling Tower and Closed-Loop Water-Source Differences
    The water entering temperature test conditions in AHRI 920-2015 
Table 2 for testing water-cooled DOAS differ from the water-source heat 
pump inlet temperature conditions specified in Table 3 for water-source 
heat pump DOAS tested using the ``water source'' test conditions. 
Water-source water loops generally provide heat rejection using cooling 
towers. Hence, it is unclear that there is much value in having 
incremental differences for the dehumidification test conditions for 
these types of equipment.
    Issue DOAS-19: DOE requests comment on the need for different 
dehumidification test conditions for a water-cooled DOAS as compared to 
a water-source heat pump DOAS using the closed water loop test 
conditions.
iii. Water-Cooled Condensing and Ground-Source Equipment
    Tables 2 and 3 in AHRI 920-2015 include two categories for water-
cooled DOASes and three categories for heat pump DOASes. The test 
standard specifies a different set of inlet water/fluid temperatures 
for each category. The different categories and their associated rating 
conditions could require some DOASes to be tested separately as 
different basic models. For example, water-cooled DOASes that can be 
operated with either chilled water or condenser water would have to be 
tested and rated in both configurations. Similarly, ASHRAE 90.1-2016 
includes three rating subcategories for water-source heat pump DOASes--
ground-source, closed loop; ground-water-source; and water-source. The 
EPCA definition for ``commercial package air conditioning and heating 
equipment'' does not include ground-water-source products (42 U.S.C. 
6311(8)(A)), but ground-source and water-source heat pumps would be 
covered by DOE with two different rating conditions. DOE is considering 
whether such dual rating and certification is appropriate.
    Issue DOAS-20: DOE requests comment on whether condenser cooling by 
cooling tower water versus chilled water demarcates two distinct 
equipment categories, or whether a single piece of equipment could 
operate in both applications. Likewise, DOE requests comments on 
whether ground-source closed-loop DOASes represent equipment that is 
distinct from water-source models. For each of these pairs of 
categories, if they do only represent different test conditions for the 
same equipment, DOE requests input on whether testing and rating 
equipment for two applications is preferable, or whether a single set 
of test conditions and rating would be sufficient.
    Section 2 of ASHRAE 198-2013 specifically excludes DOASes with 
water coils that are supplied by a chiller located outside of the unit. 
However, AHRI 920-2015 Table 2 includes operating conditions for which 
a water-cooled condenser is supplied with chilled water, and ASHRAE 
90.1-2016 established standard levels for DOASes that operate with 
chilled water as the condenser cooling fluid.
    Issue DOAS-21: DOE seeks confirmation that the ASHRAE 198-2013 
chiller exclusion applies to cooling coils rather than condenser coils.
d. Tolerances
    Rating test tolerances for DOASes are listed in Table 1 of ASHRAE 
198-2013. This table specifies tolerances for

[[Page 34439]]

airflow rate and outdoor and return air dry-bulb and wet-bulb 
temperatures, but does not list any tolerances for supply airflow 
temperature. However, tolerances for supply temperature are included in 
other relevant test procedures, such as in Table 2b of ASHRAE 37-2009. 
DOE is considering adding operating tolerances for supply airflow dry-
bulb and wet-bulb temperatures to the test procedure.
    In addition, the operating and condition tolerances listed for 
airflow rate are 5 percent in Table 1 of ASHRAE 198-2013, which is 
looser than the airflow rate tolerance adopted for CUACs. In fact, DOE 
proposed to apply  5 percent condition tolerance on cooling 
full-load indoor airflow rate for CUACs (see 80 FR 46870, 46873 (August 
6, 2015; ``August 2015 CUAC TP NOPR'')), but received several comments 
suggesting that a 5-percent tolerance would result in too much 
variation in the measurement of EER and cooling capacity. Therefore, 
DOE adopted a 3-percent tolerance in the December 2015 CUAC TP final 
rule, as suggested by stakeholder comments. 80 FR 79655, 79659-79660 
(Dec. 23, 2015). DOE has concerns that the 5-percent condition 
tolerance on airflow in ASHRAE 198-2013 may result in too much test 
variability for DOASes.
    Issue DOAS-22: DOE requests comment on whether to adopt the 
operating condition tolerances for supply air temperature listed in 
Table 2b of ASHRAE 37-2009 for DOAS testing. DOE also seeks input 
regarding whether a 5-percent airflow tolerance is acceptable. Further, 
DOE requests any information or data regarding tolerances for any other 
test operating parameters. Specifically, DOE requests comment on 
whether there are any parameters whose tolerances should be tightened 
or relaxed to ensure limited variation and high certainty for the ISMRE 
and ISCOP results with appropriate test burden.
e. Capacity Measurement
    The air enthalpy method, as specified in section 6.1 of ASHRAE 198-
2013, is the only capacity measurement method required in the test 
procedure. There is no mention of a secondary test method for capacity 
measurement verification in AHRI 920-2015 or ASHRAE 198-2013. In 
contrast, secondary capacity measurements are generally required for 
testing of air conditioners with capacity less than 135,000 Btu/h (see, 
e.g., ASHRAE 37-2009 section 7.2.1). Measurement of air conditioning 
capacity is based on the measurements of air flow rate, temperature, 
and humidity, which can have an uncertainty range associated with them 
that makes use of a secondary method to check the primary method 
worthwhile to ensure accuracy. DOE is considering whether secondary 
measurements should be required for DOAS testing in order to ensure 
accuracy of measurements. Section 7 of ASHRAE 37-2009 describes several 
different test methods applicable to testing of unitary air-
conditioning and heat pump equipment. The cooling condensate method may 
be particularly relevant as a secondary test method for measuring the 
dehumidification performance of a DOAS.
    Issue DOAS-23: DOE requests comment on the need for a secondary 
test method requirement for DOAS testing. DOE seeks input regarding 
potentially applicable secondary test methods for the dehumidification 
and heating tests, and whether a secondary test method requirement and/
or the secondary method allowed by the test procedure should depend on 
cooling (or dehumidification) capacity or airflow rate. DOE is also 
interested in detailed information on the test burden that would be 
associated with a secondary test method.
f. Test Set-Up
    Figures 1 and 2 of ASHRAE 198-2013 show the typical test set-up for 
DOASes with and without energy recovery. The figures show airflow and 
condition measuring devices at both the inlet and the outlet of each 
airstream, but it is not clear in the test standard that both airflow 
measurement devices are required. DOE notes that typically only one 
airflow measuring device, which measures airflow downstream of the 
unit, is installed in air-conditioner and heat pump testing. ASHRAE 
198-2013 provides no description of the use of two sets of airflow 
measurements per airstream, for example, for a tolerance check of the 
airflow calculation or determination of leakage between air streams 
when testing a DOAS with energy recovery.
    Issue DOAS-24: DOE requests comments on whether it is beneficial or 
necessary to use two airflow measuring devices per airstream when 
testing DOAS equipment.
    Section 6.6 of ASHRAE 198-2013, which deals with Unit Preparation, 
describes that any energy recovery devices that include a purge or 
other function that transfers air from supply or exhaust shall be 
disabled to set at zero position.
    Issue DOAS-25: DOE seeks additional information on the purge 
function mentioned in section 6.6 of ASHRAE 198-2013. Specifically, are 
all purge devices adjustable to zero purge, and is it always clear how 
to set them to zero purge? Also, DOE requests feedback on whether it is 
appropriate to set purge to zero or whether it would be more 
appropriate to set purge to its highest setting or to some standard 
setting?
    Issue DOAS-26: DOE requests any additional comments related to the 
adoption of AHRI 920-2015 as the test procedure for DOAS.

C. Test Procedure for Air-Cooled, Water-Cooled, and Evaporatively-
Cooled Equipment

    DOE's test procedures for ACUACs, ECUACs, and WCUACs are codified 
at 10 CFR 431.96. Table 1 at 10 CFR 431.96 incorporates by reference 
AHRI 340/360-2007 for WCUACs and ECUACs with cooling capacity >=65,000 
Btu/h, excluding section 6.3. For ACUACs with cooling capacity >=65,000 
Btu/h, Table 1 refers to appendix A to subpart F of part 431, which 
references sections 3, 4, and 6 of AHRI 340/360-2007, excluding section 
6.3. Paragraphs (c) and (e) of 10 CFR 431.96 and appendix A to subpart 
F of part 431 contain additional test procedure provisions for WCUACs/
ECUACs and ACUACs, respectively. ASHRAE 90.1-2016 updated its test 
procedure reference for this equipment to AHRI 340/360-2015, 
``Performance Rating of Commercial and Industrial Unitary Air-
conditioning and Heat Pump Equipment'' (AHRI 340/360-2015), which has 
triggered the requirement for DOE to review its test procedures for 
this equipment.
    At 10 CFR 431.95 and Table 1 of 10 CFR 431.96, DOE incorporates by 
reference AHRI 210/240-2008 for testing of ACUACs, WCUACs, and ECUACs 
with cooling capacity <65,000 Btu/h, excluding section 6.5. While 
ASHRAE 90.1-2016 did not update its test procedure reference for this 
equipment, AHRI has made public a draft update of AHRI 210/240 (AHRI 
210/240-2015-Draft) that was submitted to the docket for the test 
procedure for CAC/HPs on August 14, 2015 (Docket No. EERE-2009-BT-TP-
0004). For this reason, and to comply with the statutory requirement to 
review test procedures at least once every seven years (42 U.S.C. 
6314(a)(1)(A)), DOE is reviewing its test procedures for ECUACs and 
WCUACs with cooling capacity less than 65,000 Btu/h in this RFI. DOE 
will consider ACUACs with a cooling capacity less than 65,000 Btu/h in 
a separate RFI.
    The following sections explore aligning the ECUAC and WCUAC metric 
with that of ACUAC, review updates in AHRI 340/360-2015 to determine if 
adopting that industry standard would meet EPCA requirements, and 
explore

[[Page 34440]]

additional test procedure issues related to the subject equipment.
1. Energy Efficiency Descriptor
    DOE's current energy efficiency descriptor for ECUACs and WCUACs is 
the energy efficiency ratio (EER). 10 CFR 431.96. The EER metric only 
captures performance at a single set of rating conditions with 
equipment operating at full-load, and it is calculated by dividing the 
full-load cooling capacity by the equipment power input. In contrast, 
DOE adopted integrated energy efficiency ratio (IEER) as an energy 
efficiency metric for ACUACs in the December 2015 CUAC TP final rule. 
80 FR 79655 (Dec. 23, 2015). ASHRAE 90.1-2016 also provides minimum 
efficiency IEER levels (in addition to EER levels) for ECUACs and 
WCUACs.
    AHRI 340/360-2007 includes a method for testing and calculating 
IEER for ECUACs and WCUACs. IEER is an energy efficiency descriptor 
that is calculated from test results at four sets of conditions 
including a full-load test at standard rating conditions and three 
part-load tests at different outdoor conditions for ECUACs and 
different entering water temperatures for WCUACs. IEER utilizes 
adjustment factors to account for cycling losses, when applicable, at 
part-load conditions. IEER also includes continuous indoor fan 
operation, during times when the compressor would be cycling to meet 
the required load, to account for fan operation during ventilation 
mode. After the measured efficiencies at the four test conditions are 
adjusted for cycling losses and continuous fan use, if applicable, the 
results are multiplied by weighting factors and added together to 
determine the IEER. The weighting factors used are as follows: 0.020 
for the full-load test, 0.617 for the 75-percent load test, 0.238 for 
the 50-percent load test, and 0.125 for the 25-percent load test.
    Issue CUAC-1: DOE seeks comment or data on whether the IEER part-
load conditions and IEER weighting factors are representative of the 
operation of field-installed ECUACs and WCUACs. DOE also seeks comment 
or data regarding the typical cycling losses of field-installed ECUACs 
and WCUACs.
    The Appliance Standards and Rulemaking Federal Advisory Committee 
(ASRAC) Commercial and Industrial Fans and Blowers Working Group 
developed recommendations regarding the energy conservation standards, 
test procedures, and efficiency metrics for commercial and industrial 
fans and blowers in a term sheet (Docket No. EERE-2013-BT-STD-0006-
0179), which was the culmination of a negotiated rulemaking involving 
that equipment. As part of this term sheet, Recommendation #3 discussed 
the need for DOE's test procedures and related efficiency metrics to 
properly account for the energy consumption of fans embedded in 
regulated commercial air-conditioning equipment.
    In addition, the working group agreed that in the next round of 
test procedure rulemakings, DOE should consider revising efficiency 
metrics that include energy use of supply and condenser fans to include 
the energy consumption during all relevant operating modes (e.g., 
auxiliary heating mode, ventilation mode, and part-load operation). The 
working group included ACUACs, ECUACs, and WCUACs in its list of 
regulated equipment for which fan energy use should be considered. 
(Docket No. EERE-2013-BT-STD-0006-0179 at pp. 3-4, 16)
    Consequently, DOE is considering what changes to its ACUAC, ECUAC, 
and WCUAC test procedures may more accurately represent fan energy use 
in field applications. DOE is aware that field-installed fan energy use 
will vary based on the use of the fan for ancillary functions (e.g., 
economizers, ventilation, filtration, and auxiliary heat). In order to 
properly account for fan energy use, DOE is requesting information on 
how frequently field installations use the supply fan of the CUAC for 
various ancillary functions.
    Issue CUAC-2: DOE requests information, including any available 
data, on how frequently CUAC supply fans are operated when there is no 
demand for heating or cooling (i.e., for fresh air ventilation or air 
circulation/filtration), and what the typical operating schedules or 
duty cycles are for this function. Additionally, DOE requests data or 
information regarding how frequently and what forms of primary and 
auxiliary heating are installed with CUACs and whether their operation 
is dependent on the supply fan of the CUAC. DOE requests data or 
information regarding how frequently the systems are used with 
economizers, how the economizers are integrated with the systems, and 
what control logic is typically used on the economizers. DOE also seeks 
comment and information regarding the use of the indoor supply fan of 
CUACs for any ancillary functions not mentioned above. Please 
differentiate by ACUAC, ECUAC, or WCUAC, as necessary.
    Another factor that influences fan energy use is the external 
static pressure that is required to overcome the air distribution 
system pressure drop. Both AHRI 210/240-2008 and AHRI 340/360-2007 
specify minimum external static pressures for testing based on the 
rated unit capacity of ECUACs and WCUACs. DOE is interested in ensuring 
that the external static pressures in the test procedures are 
representative of those experienced in field installations. In the 
December 2015 CUAC TP final rule, DOE summarized stakeholder comments 
regarding the possibility that external static pressures as measured in 
the field may be higher than those found in the industry test 
standards. 80 FR 79655, 79664 (Dec. 23, 2015). Based on this 
information, DOE is examining the external static pressures specified 
in the test procedures for ECUACs and WCUACs.
    Issue CUAC-3: DOE requests comment or data regarding the typical 
external static pressures in field installations of ECUACs and WCUACs 
and whether these field-installed external static pressures typically 
vary with capacity. DOE also seeks comment regarding whether the field 
applications of ECUACs and WCUACs are different from ACUACs with 
regards to the typical ducting installed on the system.
    Another issue related to fan energy is the default fan power for 
ACUACs, ECUACs, and WCUACs with a coil-only configuration (i.e., 
without an integral supply fan). Current test procedures for ACUACs, 
ECUACs, and WCUACs specify that indoor fan power of 365 Watts (W) per 
1000 standard cubic feet per minute (scfm) be added to power input for 
coil-only units and that the corresponding heat addition be subtracted 
from measured cooling. This value has been used to account for the fan 
energy use associated with coil-only units for many years, and more-
efficient motors and fans may be in use for which the current 365 W/
1000 scfm fan power value is not representative. It is also possible 
that the value is not consistent with field-typical external static 
pressures.
    Issue CUAC-4: DOE seeks comment or data on the prevalence of 
ACUACs, ECUACs, and WCUACs that are sold in coil-only configurations 
(i.e., neither with an integral supply fan, nor with a designated air 
mover such as a furnace or modular blower).
    Issue CUAC-5: DOE seeks comment or data on the typical efficiency 
or typical power use and flow of fans used with coil-only ACUACs, 
WCUACs, and ECUACs in field installations.
2. Addressing Changes to AHRI 340/360
    As noted previously, ASHRAE 90.1-2016 updated its reference from 
AHRI 340/360-2007 to AHRI 340/360-2015. The updated AHRI 340/360-2015 
includes significant changes from AHRI 340/360-2007 for ACUACs, ECUACs,

[[Page 34441]]

and WCUACs, and DOE seeks comment on those changes as discussed in this 
section. Several changes are relevant to all three categories of 
equipment, while other changes are only relevant to one or two of the 
equipment categories. Table II.2 illustrates to which equipment 
category each change is relevant. In some cases, a change may not be 
relevant to ACUACs because the change has already been adopted in the 
December 2015 CUAC TP final rule.

                                      Table II.2--AHRI 340/360-2015 Changes
----------------------------------------------------------------------------------------------------------------
                            Topic                                   ACUAC            ECUAC            WCUAC
----------------------------------------------------------------------------------------------------------------
Head Pressure Controls.......................................               X                X                X
Refrigerant Charging Requirements............................               X                X                X
Adjustment for Different Atmospheric Pressure Conditions.....               X                X                X
Measurement of Condenser Air Inlet Temperature...............               X                X   ...............
Tolerance of Tested Airflow Relative to Rated Airflow........  ...............               X                X
Vertical Separation of Indoor and Outdoor Units..............               X                X                X
Outdoor Entering Air Wet-Bulb Temperature....................  ...............               X   ...............
Single-Zone Variable-Air-Volume and Multi-Zone Variable-Air-                X                X                X
 Volume......................................................
----------------------------------------------------------------------------------------------------------------

a. Head Pressure Controls
    Condenser head pressure controls regulate the flow of refrigerant 
through the condenser and/or adjust operation of condenser fans to 
prevent condenser pressures from dropping too low during low-ambient 
operation. When employed, these controls ensure that the refrigerant 
pressure is high enough to maintain adequate flow through refrigerant 
expansion devices such as thermostatic expansion valves. AHRI 340/360-
2007 provides minimal guidance on head pressure controls, only 
mentioning in note 2 of Table 6 that the condenser airflow should be 
adjusted as required by the unit controls for head pressure control. 
AHRI 340/360-2015 states that any head pressure controls shall be left 
at the manufacturer's settings and operated in automatic mode, but 
that, if this results in unstable operation exceeding the tolerances of 
ASHRAE 37-2009, the time-averaged head pressure control test described 
in section F7 of appendix F of AHRI 340/360-2015 shall be used. This 
test requires measuring performance using two one-hour test periods, 
first after approaching the target ambient condition from warmer 
temperatures, and once after approaching from lower temperatures. 
During these tests, the looser tolerance requirements from Table 2b of 
ASHRAE 37-2009 for the ``heat portion'' of the heat with defrost test 
must be met. This issue was reviewed by DOE for ACUACs in the December 
2015 CUAC TP final rule. In that final rule, DOE clarified that head 
pressure controls must be active during the test, but DOE did not adopt 
the time-averaged head pressure control test specified in AHRI 340/360-
2015, indicating that AHRI 340/360-2015 was a draft document at the 
time and that DOE would reconsider adoption of the provisions for 
testing units with head pressure control later. 80 FR 79655, 79660 
(Dec. 23, 2015).
    Issue CUAC-6: DOE seeks information and data regarding testing of 
CUACs with head pressure control that would require the special test 
provisions described in AHRI 340/360-2015. Specifically, can such units 
be tested in compliance with the relaxed stability requirements of 
these test provisions? Do the test results accurately represent field 
use? Is the test burden associated with these tests appropriate?
b. Refrigerant Charging Requirements
    AHRI 340/360-2007 does not provide any specific guidance on setting 
the refrigerant charge of a unit.
    The DOE test procedures for ACUACs, ECUACs, and WCUACs state that 
if the manufacturer specifies a range of superheat, sub-cooling, and/or 
refrigerant pressures in the installation or operation manual, any 
value within that range may be used to determine refrigerant charge, 
unless the manufacturer clearly specifies a rating value in its 
installation or operation manual, in which case the specified value 
shall be used. 10 CFR 431.96(e)(1); section (5)(i) of appendix A to 
subpart F of part 431.
    AHRI 340/360-2015 states that equipment shall be charged with 
refrigerant at standard rating conditions (or conditions specified by 
the manufacturer in the installation instructions) in accordance with 
the manufacturer's installation instructions or label applied to the 
equipment. In contrast with the DOE test procedure, the industry test 
standard calls for the use of the average of ranges of sub-cooling or 
superheat specified in installation manuals.
    As discussed in section II.A.3.e, the June 2016 CAC TP final rule 
provides a comprehensive approach for charging that improves test 
reproducibility. The approach indicates which set of installation 
instructions to use for charging, explains what to do if there are no 
instructions, indicates that target values of parameters are the 
centers of the ranges allowed by installation instructions, and 
specifies tolerances for the measured values. 81 FR 36992, 37030-37031. 
These methods could be considered as an example for the CUAC test 
method.
    Issue CUAC-7: DOE seeks comment on whether it would be appropriate 
to adopt an approach for charging requirements for commercial CUACs 
similar or identical to the approach adopted in the June 2016 CAC TP 
final rule for residential products. DOE seeks comments regarding which 
parts of the approach should or should not be adopted, and for what 
reasons they might or might not be suitable for application to CUACs. 
DOE is also interested in receiving data that demonstrate how sensitive 
the performance of ACUACs, ECUACs, and WCUACs is relative to changes in 
the various charge indicators used for different charging methods, 
specifically the method based on sub-cooling.
c. Adjustment for Different Atmospheric Pressure Conditions
    In order to address potential differences in measured results 
conducted at different atmospheric pressure conditions, AHRI 340/360-
2015 introduced an adjustment for indoor supply fan power and 
corresponding fan heat. This adjusts the fan power based on the 
barometric pressure at the test site, multiplying the measured supply 
fan power by the square of the ratio of the measured air density 
(density of air at measured supply air temperature and humidity and 
measured atmospheric pressure) to the density of the supply air if it 
were at standard pressure (14.696 pounds per square inch). 
Consequently, the cooling capacity and efficiency are also impacted by 
this correction.
    The outdoor air mass flow rate and fan power will also vary with

[[Page 34442]]

atmospheric pressure; however, the outdoor fan speed is typically not 
adjustable, because most outdoor fans have single-speed direct-drive 
motors, and no rated outdoor air flow rate in scfm is set during the 
test for the majority of CUACs. To address the potential impact of 
barometric pressure on the outdoor fan air flow, AHRI 340/360-2015 
imposed a minimum atmospheric pressure of 13.7 pounds per square inch 
absolute (psia) for testing equipment.
    Issue CUAC-8: DOE requests test data that validate the supply fan 
power correction used in AHRI 340/360-2015. DOE is also interested in 
comments on whether the minimum atmospheric pressure of 13.7 psia will 
prevent any existing laboratories from testing equipment, and what 
burden, if any, is imposed by such a requirement. DOE also seeks any 
available test data showing the impact that variations in atmospheric 
pressure have on the performance (i.e., capacity and component power 
use) of ACUACs, ECUACs, and WCUACs.
d. Measurement of Condenser Air Inlet Temperature (ACUAC and ECUAC)
    A number of requirements have been added in Appendix C of AHRI 340/
360-2015 to help ensure accurate and reproducible measurement of the 
condenser air inlet temperature. These requirements include 
specifications on the acceptable number, geometry, placement, and 
construction details of air sampling trees; specifications on the 
required accuracy of dry bulb, wet bulb, and thermopile measurement 
devices; requirements on the set-up and number of aspirating 
psychrometers; and criteria for assessing acceptable air distribution 
and control of air temperature.
    Issue CUAC-9: DOE requests comment on whether any manufacturers 
have evaluated the condenser inlet air uniformity using the criteria in 
Appendix C of AHRI 340/360-2015 for ACUACs and ECUACs and if so, 
whether any alterations to the laboratory or test set-up were necessary 
to meet those requirements. Also, DOE requests comment on whether the 
requirements of Appendix C are sufficient to ensure reproducibility of 
results and/or any test data that demonstrate sufficient 
reproducibility.
    Due to the different heat exchange process of ECUAC condensers when 
compared to ACUACs, ECUACs may have lower condenser airflow and in 
turn, smaller openings for the condenser inlet air when compared to 
ACUACs of similar capacity. Consequently, the air sampler tree and 
thermopile requirements in AHRI 340/360-2015 may not be appropriate for 
ECUACs.
    Issue CUAC-10: DOE requests comments and data on the sizes of the 
smallest and largest openings for condenser inlet air on the sides of 
ECUACs. DOE seeks comment on whether the air sampler tree requirements 
in Appendix C of AHRI 340/360-2015, specifically the requirement of 10 
to 20 branch tubes, and the thermopile requirement of having 16 
thermocouples per air sampler tree, are feasible for all ECUACs. DOE 
also seeks information regarding any alternative methods or 
measurements for determining condenser inlet air uniformity that may be 
more suitable for ECUACs.
    Issue CUAC-11: DOE requests comments and data regarding whether a 
method of measuring and specifications for uniformity of the outdoor 
inlet wet bulb temperature would benefit test reproducibility for 
ECUACs.
e. Tolerance of Tested Indoor Airflow Relative to Rated Indoor Airflow 
(ECUAC and WCUAC)
    AHRI 340/360-2007 does not provide any tolerance on the tested 
indoor airflow relative to the rated airflow of the unit under test. 
AHRI 340/360-2015 has added a 3-percent tolerance for the tested 
airflow relative to the rated airflow (i.e., the tested airflow is 
permitted to be 3 percent higher or 3 percent lower than the rated 
airflow). DOE adopted a 3 percent tolerance on indoor airflow for 
testing ACUACs in the December 2015 CUAC TP final rule to limit 
variation in EER and cooling capacity, based on test data and feedback 
provided by industry commenters. 80 FR 79655, 79659-79660 (Dec. 23, 
2015).
    Issue CUAC-12: DOE seeks comment or data showing whether variations 
in indoor airflow impact the measured efficiency or capacity of ECUACs 
and WCUACs more or less than ACUACs and whether the 3-percent tolerance 
provided in AHRI 340/360-2015 (and adopted for ACUACs in DOE's 
regulations) is appropriate for these other equipment categories.
f. Vertical Separation of Indoor and Outdoor Units
    AHRI 340/360-2007 does not limit the vertical separation of indoor 
and outdoor units when testing split systems. However, AHRI 340/360-
2015 adds a requirement that the maximum allowable vertical separation 
of the indoor and outdoor units be 10 feet, presumably because 
separation greater than 10 feet can adversely affect measured 
performance. If test facilities use indoor and outdoor environmental 
chambers that are stacked vertically, the limitation on vertical 
separation may make it impractical or impossible to test split systems.
    Issue CUAC-13: DOE seeks comment regarding whether a maximum of 10 
feet of vertical separation of indoor and outdoor units would limit the 
ability of existing facilities to test split-system ACUACs, ECUACs, or 
WCUACs. DOE also seeks comment on the impact that vertical separation 
of split systems has on efficiency and capacity.
g. Outdoor Entering Air Wet-Bulb Temperature (ECUAC)
    AHRI 340/360-2007 provides the same outdoor entering air conditions 
(i.e., 95.0 [deg]F dry bulb and 75.0 14; [deg]F wet bulb) for the 
standard rating condition (Table 3 of AHRI 340/360-2007) and the 100-
percent-capacity test point used to calculate IEER (Table 6 of AHRI 
340/360-2007) for ECUACs. While the outdoor entering air dry-bulb 
temperature is unchanged in AHRI 340/360-2015, the outdoor entering air 
wet-bulb temperature for the 100-percent-capacity test point used to 
calculate IEER was changed from 75.0 [deg]F to 74.5 [deg]F (Table 6 of 
AHRI 340/360-2015). This change suggests that two full-load tests may 
be required: One at the standard rating conditions for measuring the 
rated capacity and EER, and another at the 100-percent-capacity test 
point for the IEER test. Table 6 of AHRI 340/360-2015 also lists only 
entering air wet-bulb temperatures for ECUACs, with no corresponding 
dry-bulb temperatures.
    Issue CUAC-14: DOE seeks comment regarding the slightly different 
air wet-bulb test conditions of AHRI 340/360-2015 for standard rating 
conditions as compared with the 100-percent-capacity test point for the 
IEER test, and whether the requirement should be 75.0 [deg]F for both 
purposes.
    Issue CUAC-15: DOE seeks comment on whether the air-cooled entering 
air dry-bulb temperatures in Table 6 of AHRI 340/360-2015 apply to 
evaporatively-cooled units. If any manufacturers have developed IEER 
ratings for ECUACs using AHRI 340/360-2015, DOE requests information 
about what outdoor entering air dry-bulb temperatures were used during 
the 100-percent and part-load tests.
h. Single-Zone Variable-Air-Volume and Multi-Zone Variable-Air-Volume
    AHRI 340/360-2015 established different approaches for setting 
indoor air flow for the part-load test conditions for single-zone 
variable-air-volume (SZVAV) and multi-zone variable-air-

[[Page 34443]]

volume (MZVAV) systems (see section 6.1.3.3). The test standard defines 
MZVAV as units ``designed to vary the indoor air volume and 
refrigeration capacity/staging at a controlled discharge air 
temperature and static pressure as a means of providing space 
temperature control to independent multiple spaces with independent 
thermostats.'' (AHRI 340/360-2015 section 3.14) It defines SZVAV as 
units with a ``control system designed to vary the indoor air volume 
and refrigeration capacity/staging as a means to provide zone control 
to a single or common zones, controlled by a single space thermostat 
input.'' The SZVAV definition further explains that, ``the capacity, as 
well as the supply air flow shall be controlled either through 
modulation, discrete steps or combinations of modulation and step 
control based on the defined control logic.'' (AHRI 340/360-2015 
section 3.25)
    Part of the focus of each definition is the number of zones and 
number of thermostats involved in a system served by a given variable-
air-volume unit. However, the zones served and thermostats connected 
are part of the installation of a unit and not inherent attributes of a 
unit's characteristics. Another part of the definition addresses the 
variation of indoor air flow and capacity. For MZVAV, the air flow and 
capacity can be varied to provide a controlled discharge temperature 
and a controlled static pressure, which suggests, but does not clearly 
state, that such units have variable-capacity compressors, and that 
their indoor fan controls allow fully variable control of fan speed. In 
contrast, the SZVAV definition seems to allow modulation, steps, or a 
combination of steps and modulation for both fan and compressor 
capacity control. Based on these definitions, it seems that a unit with 
a variable-capacity compressor system and a variable-speed fan could 
meet both definitions. Also, it would appear that any unit with a 
variable-capacity compressor system that has SZVAV characteristics 
could be converted to a MZVAV system by changing the indoor fan motor 
controller or perhaps simply changing its settings.
    Issue CUAC-16: DOE requests comment on whether a CUAC model that 
could be both SZVAV and MZVAV should be tested both ways, representing 
two separate basic models. If tested as one basic model, DOE requests 
information regarding how to determine which of the two test methods 
would apply. How frequently would such a model be installed in the 
field as a SZVAV as opposed to a MZVAV? DOE also requests comment on 
whether status as a proportionally controlled unit (see AHRI 340/360-
2015 section 3.20) would be considered to be the appropriate indication 
of whether a CUAC can be used as a MZVAV unit, or whether some other 
characteristics regarding variable capacity control would have to be 
satisfied. Finally, for models that can be both SZVAV and MZVAV, how 
much do the efficiency ratings for the two configurations differ?
3. Additional Test Method Issues
    In this section, DOE explores several additional issues related to 
the test procedures for CUACs. Most issues are relevant to only ECUACs, 
but a few are also relevant to WCUACs and/or ACUACs, as shown in Table 
II.3.

                                 Table II.3--Additional CUAC Test Method Issues
----------------------------------------------------------------------------------------------------------------
                            Topic                                   ACUAC            ECUAC            WCUAC
----------------------------------------------------------------------------------------------------------------
Length of Refrigerant Line Exposed to Outdoor Conditions.....               X                X                X
Atmospheric Pressure Measurement.............................               X                X                X
Consistency Among Test Procedures for Small and Large          ...............               X                X
 Equipment...................................................
Make-up Water Temperature....................................  ...............               X   ...............
Secondary Measurement Method for Capacity....................  ...............               X   ...............
Piping Evaporator Condensate to Condenser Pump...............  ...............               X   ...............
Purge Water Settings.........................................  ...............               X   ...............
Condenser Spray Pumps........................................  ...............               X   ...............
Additional Steps to Verify Proper Operation..................  ...............               X   ...............
----------------------------------------------------------------------------------------------------------------

a. Length of Refrigerant Line Exposed to Outdoor Conditions
    AHRI 340/360-2007, AHRI 340/360-2015, AHRI 210/240-2008, and AHRI 
210/240-2015-Draft all require at least 25 feet of interconnecting 
refrigerant line when testing split-systems. However, both versions of 
AHRI 340/360 require that at least 5 feet of the interconnecting 
refrigerant line must be exposed to outdoor test chamber conditions, 
while both versions of AHRI 210/240 require at least 10 feet be so 
exposed. DOE has estimated an upper bound of the capacity loss to be 
approximately 1 percent of the capacity of the unit for 10 feet of 
refrigerant line located in the outdoor chamber and approximately 0.5 
percent for 5 feet.
    Issue CUAC-17: DOE seeks comment or data regarding the typical 
length of refrigerant line that is exposed to outdoor conditions on 
split-system ACUAC, ECUAC or WCUAC installations and whether this 
length varies depending on the capacity of the unit. DOE also seeks 
comment or data on any measurements or calculations that have been made 
of the losses associated with refrigerant lines located in the outdoor 
chamber and whether the impact is larger or smaller than DOE's estimate 
of approximately 1 percent of capacity per 10 feet of refrigerant line 
located in the outdoor chamber.
b. Atmospheric Pressure Measurement
    The accuracy of atmospheric pressure measurements required by 
section 5.2.2 of ASHRAE 37-2009 (which is referenced by AHRI 340/360-
2015) is 2.5 percent. This level of uncertainty can result 
in error when calculating the indoor entering and leaving air 
enthalpies and resulting cooling capacity. Under certain circumstances, 
atmospheric pressure measurements at the extremes of this tolerance 
result in capacity measurement errors of 1-2 percent.
    Issue CUAC-18: DOE seeks comment on the typical accuracy of the 
atmospheric pressure sensors used by existing test laboratories.
c. Consistency Among Test Procedures for Small and Large ECUAC and 
WCUAC Equipment Classes
    The current test procedure and referenced industry standard for 
ECUACs and WCUACs that have cooling capacities less than 65,000 Btu/h 
(AHRI 210/240-2008) reference the same test method (ASHRAE 37-2005) and 
contain the same efficiency metrics as those for units with capacities 
greater than or equal to 65,000 Btu/h (AHRI 340/360-2007). However, 
there are some differences that have been identified in this section. 
DOE is considering whether the

[[Page 34444]]

consistency of test procedures could be improved by referencing a 
single industry standard for all cooling capacities of ECUACs and 
WCUACs. The updated industry standard for rating units with a capacity 
greater than or equal to 65,000 Btu/h (AHRI 340/360-2015) has 
significant changes that affect the testing of ECUACs and WCUACs. 
However, the industry standard for rating units with a cooling capacity 
less than 65,000 Btu/h is in the process of being updated and could 
potentially be finalized with better consistency with AHRI 340/360 for 
testing of this equipment.
    Issue CUAC-19: DOE requests comment on whether there are 
differences between ECUACs and WCUACs that have cooling capacities less 
than 65,000 Btu/h and those that have cooling capacities greater than 
or equal to 65,000 Btu/h that justify the incorporation by reference of 
different industry test standards for the different cooling capacity 
ranges. If not, DOE seeks feedback on whether referencing a single 
industry standard for units of all cooling capacities would be 
beneficial and/or whether there could or should be better consistency 
between the test standards for testing of this equipment. Specifically, 
DOE requests comment on whether there are actual differences in field 
installations and field use of this equipment and on the extent to 
which these differences impact performance.
d. Make-Up Water Temperature (ECUAC)
    Neither AHRI 340/360-2007 nor AHRI 340/360-2015 provide any 
requirements on the make-up water temperature for the standard rating 
condition or for the part-load IEER tests. Make-up water must be 
supplied to the sump of an ECUAC to replenish the evaporated water (or 
to spray nozzles for models without sumps). AHRI 210/240-2008 and AHRI 
210/240-2015-Draft specify 85.0[emsp14][deg]F for the full-load 
standard rating condition and 77.0[emsp14][deg]F for the part-load 
tests. Cooler makeup water temperature could increase measured cooling 
capacity and vice versa, causing variation in measurements if specific 
temperatures are not required.
    Issue CUAC-20: DOE seeks comment or data regarding the impact that 
the make-up water temperature has on the unit performance. DOE also 
seeks comment or data on whether the make-up water temperatures, 
including the temperatures for part-load conditions, specified in AHRI 
210/240-2008 and AHRI 210/240-2015-Draft are representative of 
conditions experienced by field-installed ECUACs of all cooling 
capacities.
e. Secondary Measurement Method for Capacity (ECUAC)
    ASHRAE 37-2009 requires the indoor air enthalpy method plus an 
additional secondary method for calculating the test equipment capacity 
for all units with less than 135,000 Btu/h rated capacity. The test 
standard lists applicable test methods in Table 1, but this table does 
not indicate that the outdoor air enthalpy method is applicable for any 
configuration of evaporatively-cooled equipment. Therefore, the 
secondary method for ECUACs is limited to use of the refrigerant 
enthalpy method or compressor calibration method for split systems and 
only the compressor calibration method for single-package equipment. 
DOE recognizes that the refrigerant enthalpy method and compressor 
calibration method can, in some circumstances, add burden to the 
testing procedure, so DOE examined the potential use of the outdoor air 
enthalpy method as a secondary method for ECUACs. During testing, DOE 
observed that the part-load test conditions produce an environment 
where condensation is likely in the outdoor unit supply duct, because 
the outdoor air dry bulb temperature cooling the duct walls can be 
lower than the dew point of the warm moist air leaving the outdoor 
unit. This condensation would be unaccounted for by the outdoor air 
enthalpy method, resulting in a calculated capacity less than the 
actual capacity. To consider another approach, DOE notes that it 
modified the CAC/HP test method to require a secondary capacity 
measurement only for full-load operation for cooling and heating, 
rather than for all tests in a January 5, 2017 final rule. 82 FR 1426, 
1441. While this change was for central air conditioners and heat 
pumps, limiting the secondary method test to a single set of 
conditions, such as the full-load cooling (and heating, if applicable) 
test conditions, would eliminate or reduce the potential for 
condensation in the outdoor supply duct when testing ECUACs.
    Issue CUAC-21: DOE seeks comment or test data on the difficulty of 
getting a match of primary and secondary capacity measurements when 
testing ECUACs with rated capacities less than 135,000 Btu/h and 
whether the difficulty level is higher, lower, or the same when testing 
the unit at full-load conditions as compared to part-load conditions. 
DOE also seeks comment and data on how often the primary capacity 
measurement results in an exceeded allowable percent difference between 
the primary and secondary capacity measurements.
    Issue CUAC-22: DOE seeks comment on whether single-package ECUACs 
with a rated cooling capacity less than 135,000 Btu/h are currently 
sold.
    Issue CUAC-23: DOE seeks comment on whether manufacturers would see 
a benefit in allowing the outdoor air enthalpy method as a secondary 
capacity measurement for ECUACs. If so, DOE is interested in feedback 
on methods to mitigate the risk of condensation in the outdoor unit 
supply duct and the outdoor supply wet-bulb sample station. DOE also 
asks if other alternative approaches could be considered for mitigating 
the potential test burden associated with the secondary test methods 
that ASHRAE 37-2009 specifies for evaporatively-cooled equipment.
f. Piping Evaporator Condensate to Condenser Pump (ECUAC)
    Some split-system ECUACs provide the option for piping evaporator 
condensate to the condenser sump. This reduces the make-up water use of 
the unit and may provide some performance improvement. Neither DOE's 
current test procedures nor the industry ECUAC test standards address 
this potential variation, which could result in differences in test 
results depending on whether this feature was employed in a test.
    Issue CUAC-24: DOE seeks comment on whether ECUACs that allow 
piping of evaporator condensate to the condenser sump present any 
complications (e.g., maintaining proper slope in the piping from the 
evaporator to the outdoor unit and test repeatability issues) when 
testing in a laboratory. DOE also seeks comment or data indicating what 
kind of impact piping the evaporator condensate to the condenser sump 
has on the efficiency and/or capacity of ECUACs.
g. Purge Water Settings (ECUAC)
    Some ECUACs require the sump water to be continuously or 
periodically purged in order to reduce mineral and scale build-up on 
the condenser heat exchanger. AHRI 340/360-2015 provides guidance to 
set up and configure the unit per the manufacturer's installation 
instructions, which would include setting the purge rate if specified.
    Issue CUAC-25: DOE seeks comment on how the purge water rate should 
be set for laboratory testing if the manufacturer's installation 
instructions do not contain information on this topic.

[[Page 34445]]

h. Condenser Spray Pumps (ECUAC)
    The rate that water is sprayed on the condenser coil may have an 
impact on the performance of an ECUAC. For units with sumps, this rate 
may be affected by the pump set-up, and, for units without sumps, the 
incoming water pressure may have an impact. Neither DOE's current test 
procedures nor the industry ECUAC test standards address these 
potential variations.
    Issue CUAC-26: DOE requests comment on whether the pump flow can be 
adjusted on any ECUACs on the market that have circulation pumps. DOE 
also requests comment on whether ECUACs without a sump exist and, if 
so, whether there are requirements on the incoming water pressure to 
ensure proper operation of the spray nozzles. DOE also requests 
comments and/or data regarding the sensitivity of performance test 
results to these adjustments.
i. Additional Steps To Verify Proper Operation (ECUAC)
    Some ECUACs may use spray nozzles with very small diameter openings 
that may become easily clogged, thereby reducing the effectiveness of 
the heat exchanger.
    Issue CUAC-27: DOE requests comment on whether there are any 
additional steps that should be taken to verify proper operation of 
ECUACs during testing, such as ensuring nozzles are not blocked.
    Issue CUAC-28: DOE requests comment on any additional issues 
associated with adopting AHRI 340/360-2015 for ACUACs, ECUACs, and 
WCUACs.

D. Test Procedure for Variable Refrigerant Flow Multi-Split Air 
Conditioners and Heat Pumps

    DOE's commercial equipment regulations include test procedures and 
energy conservation standards that apply to air-cooled VRF multi-split 
air conditioners, air-cooled VRF multi-split heat pumps, and water-
source VRF multi-split heat pumps, all with cooling capacity less than 
760,000 Btu/h, except air-cooled, single-phase VRF multi-split air 
conditioners and heat pumps with cooling capacity less than 65,000 Btu/
h (which are covered by DOE's consumer product regulations for central 
air conditioners \12\). 10 CFR 431.96 and 431.97.
---------------------------------------------------------------------------

    \12\ See 10 CFR 430.32(c) and Appendix M and M1 to Subpart B of 
Part 430.
---------------------------------------------------------------------------

    DOE's test procedure for (commercial) VRF multi-split systems is 
codified at 10 CFR 431.96 and was established in the May 2012 final 
rule. 77 FR 28928 (May 16, 2012). DOE's current regulations require 
that manufacturers test VRF multi-split systems using AHRI 1230-2010 
with addendum 1, except for sections 5.1.2 and 6.6. DOE's current test 
procedure also requires that manufacturers adhere to certain additional 
requirements listed in 10 CFR 431.96(c)-(f). Although ASHRAE 90.1-2016 
did not update its test procedure reference for VRF (AHRI 1230-2010 
with addendum 1), DOE is reviewing its test procedure in response to 
the seven-year-lookback statutory review requirement (see 42 U.S.C. 
6314(a)(1)(A)), and in advance of its review of energy conservation 
standards for VRF in response to changes in ASHRAE 90.1-2016.
    As part of its seven-year-lookback review, DOE is examining updated 
industry test standards, including Addendum 2 to AHRI 1230-2010 
(approved June 2014) and a draft version of AHRI 1230 provided by AHRI 
for the docket that will supersede AHRI 1230-2010 (with Addendum 1 and 
2) once published (``AHRI 1230-Draft,'' No. 1). DOE reviewed the AHRI 
1230-Draft and discusses in the following sections specific issues 
regarding the draft and other items related to the VRF test procedure.
1. Energy Efficiency Descriptors
    DOE currently prescribes energy conservation standards for air-
cooled VRF multi-split systems with cooling capacity greater than or 
equal to 65,000 Btu/h and water-source VRF multi-split systems in terms 
of the EER metric for cooling-mode operation and in terms of the 
coefficient of performance (COP) metric for heating-mode operation.\13\ 
DOE is considering whether to add or replace the existing cooling-mode 
efficiency descriptor (i.e., EER) with a new cooling-mode energy-
efficiency descriptor that better captures part-load performance, such 
as IEER.
---------------------------------------------------------------------------

    \13\ DOE also prescribes energy conservation standards for 
three-phase air-cooled VRF multi-split systems with cooling capacity 
less than 65,000 Btu/h in terms of the SEER metric for cooling-mode 
operation and in terms of the heating seasonal performance factor 
(HSPF) metric for heating-mode operation.
---------------------------------------------------------------------------

    IEER factors in the efficiency of operating at part-load conditions 
of 75-percent, 50-percent, and 25-percent of capacity, as well as the 
efficiency at full-load. The IEER metric provides a more representative 
measure of energy consumption in actual operation by weighting the 
full-load and part-load efficiencies with the average amount of time 
equipment spends operating at each load point. ASHRAE 90.1 has 
specified an IEER metric for commercial air conditioning and heat pump 
equipment since the 2008 Supplement to Standard 90.1-2007, effective 
January 1, 2010.14 15 ASHRAE Standard 90.1-2013 included 
minimum efficiency levels for both the EER and IEER of air-cooled VRF 
multi-split systems and for the EER of water-source VRF multi-split 
systems. ASHRAE Standard 90.1-2016 added IEER levels for water-source 
VRF multi-split systems, including units with cooling capacity less 
than 65,000 Btu/h. DOE notes that in addition to ASHRAE 90.1, both the 
ENERGY STAR and Consortium for Energy Efficiency (CEE) programs use the 
IEER metric for VRF systems.16 17
---------------------------------------------------------------------------

    \14\ ASHRAE Standard 90.1 first specified a part-load 
performance metric in the 2007 edition, which used integrated part 
load value (IPLV).
    \15\ ASHRAE, ASHRAE Addenda (2008 Supplement) (Available at: 
http://www.ashrae.org/File%20Library/docLib/Public/20090317_90_1_2007_supplement.pdf).
    \16\ ENERGY STAR Program Requirements, Product Specifications 
for Light Commercial HVAC (Available at: https://www.energystar.gov/sites/default/files/specs//private/LC_HVAC_V2.2.pdf).
    \17\ Consortium for Energy Efficiency, CEE Commercial Unitary AC 
and HP Specification (Available at: http://www.cee1.org/files/CEE_CommHVAC_UnitarySpec2012.pdf).
---------------------------------------------------------------------------

    On January 15, 2016, DOE published a direct final rule for energy 
conservation standards for small, large, and very large air-cooled 
commercial package air conditioners and heat pumps (CUACs and CUHPs), 
which amended the energy conservation standards for CUACs and CUHPs and 
changed the cooling efficiency metric from EER to IEER. 81 FR 2420. 
Except possibly for ventilation, VRF multi-split systems serve the same 
primary functions as CUACs and CUHPs (i.e., space heating and cooling 
commercial buildings) and are used in a similarly wide range of 
climatic conditions.
    Because the vast majority of cooling and heating loads do not 
demand operation at full-load, the full-season metric IEER may capture 
the efficiency of VRF multi-split systems operating in the field more 
realistically than does the full-load metric EER. DOE believes that the 
publication of IEER ratings for most units on the market (as in AHRI's 
Directory of Certified Product Performance for VRF multi-split 
systems), as well as the inclusion of minimum efficiency levels and 
test procedures for IEER of VRF multi-split systems in ASHRAE Standard 
90.1-2016 and AHRI 1230-2010, respectively, demonstrate that IEER is an 
industry-accepted metric for measuring efficiency of VRF multi-split 
systems. For these reasons, DOE is considering replacing the current 
EER metric for VRF multi-split systems with

[[Page 34446]]

the full-season IEER metric, or adding IEER in addition to EER. DOE's 
ultimate decision will be impacted by the separate energy conservation 
standards rulemaking considering the efficiency levels for VRF in 
ASHRAE 90.1-2016.
    Issue VRF-1: DOE requests comment on issues DOE should consider 
regarding potentially using IEER as an efficiency metric for energy 
conservation standards for air-cooled VRF multi-split systems with a 
cooling capacity greater than or equal to 65,000 Btu/h and all water-
source VRF multi-split systems, so as to capture efficiency in part-
load operation.
2. Representativeness and Repeatability
    Operation of VRF multi-split systems is inherently variable, and 
DOE notes that the control systems of VRF multi-split systems can be 
significantly more sophisticated than control systems in other 
commercial HVAC systems. In order to achieve steady-state operation, it 
is generally necessary for a manufacturer's representative that is 
knowledgeable about the control system to be present during testing in 
order to override the typical dynamic control and to set each 
individual component at a fixed position or speed. It may be possible 
to achieve ``full-load'' capacity and/or part-load operation in 
different ways, all of which may be consistent with the test procedure 
and manufacturer's installation instructions.
    Issue VRF-2: DOE seeks comment on the settings required to be 
reported in order for third-party laboratories to reproduce unit 
performance in a rating test.
    Section 6.3.4 of AHRI 1230-Draft requires that for air-cooled VRF 
multi-split systems with a cooling capacity less than 65,000 Btu/h, at 
least one indoor unit must be turned off for tests conducted at minimum 
compressor speed. DOE also established a similar requirement for CACs 
in the June 2016 CAC TP final rule. 81 FR 36992, 37038 (June 8, 2016). 
However, AHRI 1230-Draft does not include a corresponding requirement 
for equipment with a cooling capacity greater than or equal to 65,000 
Btu/h or for water-source VRF multi-split systems. This requirement for 
equipment less than 65,000 Btu/h considers the wide range of loads that 
can occur in the field. However, DOE expects that load diversity would 
also be an issue for larger-capacity VRF multi-split systems used in 
commercial applications.
    Issue VRF-3: DOE requests information and data on the field 
operating states of indoor units of VRF multi-split systems when 
operating at low compressor speeds (i.e., near 25-percent load). 
Specifically, are there field data available that show operating states 
of VRF multi-split systems at different load levels? Such data might 
show what happens with indoor fan speeds and expansion devices of 
indoor units at low load percentages, including whether any indoor fans 
shut off, or whether any refrigerant flow control devices shut off 
refrigerant flow, and how this might be affected by the user-accessible 
control positions set for the indoor units. DOE is also interested in 
whether indoor unit operation at low compressor speeds is different in 
field application for VRF multi-split systems with cooling capacities 
less than 65,000 Btu/h than those with capacities greater than or equal 
to 65,000 Btu/h, and whether these trends follow at intermediate 
compressor speeds as well. Further, DOE requests data that would show 
the trends of total system capacity, total indoor air flow, and 
sensible heat ratio as a function of compressor speed (e.g., percentage 
of full-speed revolutions per minute) for laboratory rating tests of 
typical VRF multi-split systems conducted either with one or no indoor 
unit shut off at the lowest load point.
3. Test Method
a. Transient Testing: Oil Recovery Mode
    AHRI 1230-Draft refers to ASHRAE 37-2009 for provisions for 
transient tests, which are required when defrost interferes with 
steady-state operation sufficiently frequently to prevent completion of 
a steady-state test (see, for example, sections 8.8.2.5.1 and 8.8.2.5.2 
of that test standard). Specific instructions are provided for how to 
determine an average heating capacity for the transient test, with 
different instructions depending on the number and completion of 
defrost cycles. Tables 2a and 2b of ASHRAE 37-2009 specify the test 
tolerances to be used when conducting a transient heating capacity 
test.
    VRF multi-split systems may periodically operate in an oil recovery 
mode in order to return oil from the refrigeration loop to the 
compressor. Section 5.1.3 of AHRI 1230-Draft requires that if a 
manufacturer indicates that a VRF multi-split system is designed to 
recover oil more frequently than every two hours of continuous 
operation, the oil recovery mode shall be activated during testing, and 
the additional power shall be included in the efficiency calculations. 
However, there is no specific instruction in the AHRI 1230-Draft that 
indicates how the additional power should be incorporated into the 
efficiency metric. DOE expects that maintenance of steady-state 
conditions may be affected during oil recovery mode and that, as a 
result, some type of transient test procedure may be appropriate when 
oil recovery mode happens during testing. However, AHRI 1230-Draft does 
not specify use of the transient test for this case, and the ASHRAE 37-
2009 description of the transient test does not mention oil recovery. 
DOE notes that VRF multi-split systems vary in the way they activate 
oil recovery mode; some may initiate oil recovery mode at a set time 
interval, and others may instead initiate oil recovery mode only when 
the system detects that the oil level in the compressor has reached a 
certain minimum level. DOE understands that unit performance may vary 
with the oil level. Consequently, DOE is considering requiring all 
measurements to be made within a certain time after the last oil 
recovery to ensure repeatability between tests.
    Issue VRF-4: DOE requests comment on the impact of oil recovery 
mode, including power input and heating/cooling provided to space 
during oil recovery mode. DOE also requests comment on whether any VRF 
multi-split systems operate in oil recovery mode more frequently than 
every two hours of continuous operation. For such systems, DOE requests 
comment on whether the test method should be modified to address the 
transient operation occurring during and after oil recovery, and how 
this should be done. In addition, DOE requests comment on the 
performance variation associated with oil level and whether all 
measurements should be made within a certain time after the last oil 
recovery. Lastly, DOE requests comment on how the energy use of oil 
recovery mode might be addressed in the test procedure without imposing 
excessive test burden.
b. Airflow Setting and Minimum External Static Pressure
    DOE notes AHRI 1230-Draft contains one set of instructions for 
setting the indoor air flow rates for systems with capacities less than 
65,000 Btu/h (section 6.3.3.1) and another set for systems with 
capacities larger than 65,000 Btu/h (section 6.4.1). It is not clear 
why alternate approaches are required for different systems because the 
indoor units generally do not differ by system capacity.
    Issue VRF-5: DOE requests comment on whether there should be a 
consistent approach for setting indoor airflow across all capacity 
ranges of VRF multi-split systems.

[[Page 34447]]

c. Condenser Head Pressure Controls
    Condenser head pressure controls regulate the flow of refrigerant 
through the condenser and/or adjust operation of condenser fans to 
prevent condenser pressures from dropping too low during low-ambient 
operation. When employed, these controls ensure that the refrigerant 
pressure is high enough to maintain adequate flow through refrigerant 
expansion devices such as thermostatic expansion valves. In the 
December 2015 CUAC test procedure final rule, DOE required that CUACs 
and CUHPs equipped with head pressure controls have these controls 
activated during testing. 80 FR 79655, 79660 (Dec. 23, 2015). For VRF 
multi-split systems equipped with heat recovery, it is unclear whether 
the head pressure would be elevated when one of the indoor units calls 
for heating during cooling-based operation. It is also not clear how 
the head pressure differs during cool outdoor conditions between units 
with and without heat recovery function.
    Issue VRF-6: DOE requests comment on the appropriateness of 
requiring head pressure control activation during testing of VRF multi-
split systems. In addition, DOE requests comment on any methods to 
control VRF multi-split systems during testing to ensure stable 
operation with head pressure controls activated. Further, DOE requests 
comment on any methods that could be added to the test procedure for 
calculation of system efficiency of VRF multi-split systems if head 
pressure controls prevent stable operation at low-ambient, part-load 
conditions.
d. Air Volume Rate for Non-Ducted Indoor Units
    DOE notes the following issues associated with testing multi-split 
systems with free discharge air flow from the indoor unit (i.e., 
airflow provided directly from the indoor unit to the conditioned space 
without the use of ducts). In testing, if a common duct is used for the 
combined discharge airflow of multiple individual units, the airflow 
for each individual unit cannot be verified. Second, even if the ESP is 
set to zero--which is intended to replicate operation without ducting--
based on a measurement of downstream pressure in a discharge duct, this 
does not always guarantee that flow is identical to free discharge 
conditions, due to sensitivity of such in-duct pressure measurements to 
the air movement in the duct. Finally, specification of unusually high 
air flows for testing of free discharge in indoor units may boost 
measured performance inconsistent with field operation. Section 
6.3.3.1.1.3 of AHRI 1230-Draft added an upper limit on air flow per 
capacity for non-ducted units for systems with capacity less than 
65,000 Btu/h--the rated air volume for each indoor unit must not exceed 
55 scfm per 1,000 Btu/h.\18\
---------------------------------------------------------------------------

    \18\ DOE notes that test methods associated with the indoor 
units of systems with capacity <65,000 Btu/h are relevant for 
testing of systems with capacity >=65,000 Btu/h because the 
capacities of the indoor units are comparable.
---------------------------------------------------------------------------

    Issue VRF-7: DOE requests comment on how to confirm air flow for 
each indoor unit individually when there is a common duct for each unit 
and when there is potential deviation from free-discharge operation if 
a discharge duct is connected. DOE also requests comment on whether 
there should be an upper limit of air flow per capacity for non-ducted 
units, such as the 55 scfm per 1,000 Btu/h limit in the AHRI 1230-
Draft.
e. Secondary Test Method
    In AHRI 1230-Draft, ASHRAE 37-2009 is referenced as the test 
procedure for both air-cooled and water-cooled units across all 
capacities. Section 7.2.1 in ASHRAE 37-2009 requires a secondary test 
method in addition to the primary method (i.e., indoor air enthalpy 
method) for units having a total cooling capacity less than 135,000 
Btu/h. ASHRAE 37-2009 provides multiple options for the secondary test 
method. For units with a cooling capacity larger than 135,000 Btu/h, 
section 7.2.2 of ASHRAE 37-2009 only requires a single method, but 
provides multiple test method options.
    Section 11.1.1.7 of AHRI 1230-Draft indicates the redundant 
measurement verification method as an alternative to refrigerant 
enthalpy method or outdoor enthalpy method when they cannot be 
performed. However, the draft does not provide guidance on how to 
determine whether the refrigerant enthalpy method or outdoor enthalpy 
method can or cannot be performed. DOE is considering whether there are 
other alternatives to the refrigerant enthalpy method or outdoor 
enthalpy method (other than the duplicate measurement method), such as 
the cooling condensate and indirect airflow measurement method.
    Issue VRF-8: DOE requests comment on the methods generally used for 
measurement of capacity when testing VRF multi-split systems and 
whether the selection of methods differs between cooling and heating 
tests. DOE requests comment on how to determine whether the refrigerant 
enthalpy method or outdoor air enthalpy method (for units having a 
total cooling capacity less than 135,000 Btu/h) can or cannot be 
performed. DOE also requests comment on how to standardize the 
selection of test methods for measuring the capacity of VRF multi-split 
systems. Finally, DOE requests comment on whether there are issues with 
achieving heat balance in part-load tests for VRF multi-split systems, 
similar to those cited for variable speed CAC/HP, and if so, whether 
there is sufficient assurance of proper measurement for all test points 
of VRF multi-split systems if the heat balance is verified only for 
full capacity.
f. Heat Recovery
    VRF multi-split systems with heat recovery include a heat recovery 
unit (sometimes referred to as a branch circuit controller) that 
controls refrigerant flow between indoor units, allowing for 
simultaneous cooling and heating operation. However, DOE believes that 
VRF multi-split systems with the heat recovery capability may be able 
to operate without the heat recovery unit attached, although in such 
case, simultaneous heating and cooling would not be possible. It is not 
clear in AHRI 1230-Draft whether VRF multi-split systems capable of 
heat recovery must be tested with the heat recovery unit attached in 
tests for determining EER, IEER, and COP. DOE seeks clarification on 
industry practice for testing VRF multi-split systems with the heat 
recovery feature because attachment of the heat recovery unit may 
affect test results.
    Issue VRF-9: DOE seeks comment on whether VRF multi-split systems 
with the heat recovery feature can be operated without the heat 
recovery unit attached, and if so, whether such systems are typically 
tested for determining EER, IEER, and COP with the heat recovery unit 
attached. Additionally, DOE seeks data showing the difference in test 
results between having the heat recovery unit attached or not.
4. Representations
a. Tested Combination
    AHRI specified requirements for tested combinations for systems 
with capacities more than 65,000 Btu/h in section 6.2.2 of the AHRI 
1230-Draft. The AHRI requirement specifies selecting standard 4-way 
ceiling cassette indoor units with the smallest coil volume per nominal 
capacity for non-ducted indoor units and selecting mid-static units for 
ducted indoor units. DOE is aware that there is a range of ductless 
indoor unit styles, which may have a range of efficiency 
characteristics. In

[[Page 34448]]

addition, ducted systems may serve a range of external static 
pressures.
    A report by the Cadeo Group \19\ indicates that 4-way ceiling 
cassettes are the most prevalent non-ducted indoor units. On the other 
hand, while DOE notes that ducted units can be classified by the amount 
of static pressure they produce as either low-static, mid-static, or 
conventional-static units, DOE has no data indicating which ducted unit 
style or static pressure classification is the most prevalent.
---------------------------------------------------------------------------

    \19\ Cadeo Report. See docket: EERE-2017-BT-TP-0018. No. 2. The 
report presents market share by VRF multi-split system equipment 
class, based on confidential sales data given in interviews with 
several major manufacturers of VRF multi-split equipment and DOE's 
CCMS database.
---------------------------------------------------------------------------

    Issue VRF-10: DOE requests comment and data on variation of system 
efficiency related to indoor unit styles (both for ducted and non-
ducted indoor units). For example, for a system tested with non-ducted 
units, what is the potential range of EER and/or IEER comparing the 
most-efficient indoor units with the most energy-intensive indoor 
units? DOE requests comment on its assumption that 4-way ceiling 
cassettes are the most prevalent non-ducted indoor unit style. DOE also 
requests data on the most prevalent style and static pressure 
classification (low-static, mid-static, or conventional-static) of 
ducted units.
b. Determination of Represented Values
    DOE recognizes that non-ducted indoor units and ducted indoor units 
operate at different levels of ESP and have different limitations on 
ESP. The ESP affects the power consumed by the indoor fan, and, 
therefore, also affects the measured efficiency of a VRF multi-split 
system. DOE is considering requiring separate ratings for different ESP 
levels to account for differences between ducted indoor units, non-
ducted indoor units, and possibly other distinctions in indoor units.
    Issue VRF-11: DOE requests comment on how many distinctly 
identifiable ESP levels are generally represented in a family of VRF 
multi-split systems and what ESP levels are typical for VRF multi-split 
systems. DOE also requests data that demonstrate how different ESP 
levels affect measured efficiency for the system, both in terms of EER 
and IEER.
    Issue VRF-12: DOE requests comment on what specific topics 
pertaining to the test procedure for VRF multi-split air conditioners 
and heat pumps, in addition to the topics discussed previously, are not 
fully or appropriately addressed in the docketed AHRI-1230-Draft.

E. Other Test Procedure Topics

    In addition to the issues identified earlier in this document, DOE 
welcomes comment on any other aspect of the existing test procedures 
for commercial package air conditioning and heating equipment that is 
the subject of this notice not already addressed by the specific areas 
identified in this document. DOE particularly seeks information that 
would improve the representativeness of the test procedures, as well as 
information that would help DOE create a procedure that would limit 
manufacturer test burden through streamlining or simplifying testing 
requirements. Comments regarding repeatability and reproducibility are 
also welcome.
    DOE also requests feedback on any potential amendments to the 
existing test procedures that could be considered to address impacts on 
manufacturers, including small businesses. Regarding the Federal test 
methods, DOE seeks comment on the degree to which the DOE test 
procedures should consider and be harmonized with the most recent 
relevant industry standards for the commercial package air conditioning 
and heating equipment that is the subject of this notice, and whether 
there are any changes to the Federal test methods that would provide 
additional benefits to the public.
    Additionally, DOE requests comment on whether the existing test 
procedures limit a manufacturer's ability to provide additional 
features to consumers on the commercial package air conditioning and 
heating equipment that is the subject of this notice. DOE particularly 
seeks information on how the test procedures could be amended to reduce 
the cost of new or additional features and make it more likely that 
such features are included on the equipment.

III. Submission of Comments

    DOE invites all interested parties to submit in writing by August 
24, 2017, comments, data, and information on matters addressed in this 
notice and on other matters relevant to DOE's consideration of amended 
test procedures for VRF multi-split systems, CRAC and DOAS equipment, 
and water-cooled, evaporatively-cooled, and air-cooled commercial 
unitary air conditioners (WCUACs, ECUACs, and ACUACs). These comments 
and information will aid in the development of a test procedure NOPR 
for the subject VRF multi-split systems, and CRAC, DOAS, WCUAC, ECUAC, 
and ACUAC equipment, if DOE determines that amended test procedures may 
be appropriate for these products.
    Instructions: All submissions received must include the agency name 
and docket number and/or RIN for this rulemaking. No telefacsimilies 
(faxes) will be accepted.
    Docket: The docket is available for review at https://www.regulations.gov, including Federal Register notices, comments, and 
other supporting documents/materials. All documents in the docket are 
listed in the https://www.regulations.gov index. However, not all 
documents listed in the index may be publicly available, such as 
information that is exempt from public disclosure.
    A link to the docket Web page can be found at: https://www.regulations.gov/docket?D=EERE-2017-BT-TP-0018. This Web page 
contains a link to the docket for this notice on the https://www.regulations.gov Web site. The https://www.regulations.gov Web page 
contains instructions on how to access all documents, including public 
comments, in the docket.
    For information on how to submit a comment, review other public 
comments and the docket, or participate in the public meeting, contact 
the Appliance Standards Program at (202) 586-6636 or by email: 
[email protected]. DOE considers public 
participation to be a very important part of the process for developing 
test procedures and energy conservation standards. DOE actively 
encourages the participation and interaction of the public during the 
comment period at each stage of the rulemaking process. Interactions 
with and between members of the public provide a balanced discussion of 
the issues and assist DOE in the rulemaking process. Anyone who wishes 
to be added to the DOE mailing list to receive future notices and 
information about this rulemaking should contact Appliance and 
Equipment Standards Program staff at (202) 586-6636 or by email at 
[email protected].
    Submitting comments via https://www.regulations.gov. The https://www.regulations.gov Web page will require you to provide your name and 
contact information. Your contact information will be viewable to DOE 
Building Technologies staff only. Your contact information will not be 
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name (if any), and submitter representative name (if any). If your 
comment is not processed properly because of technical difficulties, 
DOE will use this information to contact you. If DOE cannot read your 
comment due to

[[Page 34449]]

technical difficulties and cannot contact you for clarification, DOE 
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person submitting information that he or she believes to be 
confidential and exempt by law from public disclosure should submit via 
email, postal mail, or hand delivery/courier two well-marked copies: 
One copy of the document marked ``confidential'' including all the 
information believed to be confidential, and one copy of the document 
marked ``non-confidential'' with the information believed to be 
confidential deleted. Submit these documents via email or on a CD, if 
feasible. DOE will make its own determination about the confidential 
status of the information and treat it according to its determination.
    Factors of interest to DOE when evaluating requests to treat 
submitted information as confidential include: (1) A description of the 
items, (2) whether and why such items are customarily treated as 
confidential within the industry, (3) whether the information is 
generally known by or available from other sources, (4) whether the 
information has previously been made available to others without 
obligation concerning its confidentiality, (5) an explanation of the 
competitive injury to the submitting person which would result from 
public disclosure, (6) when such information might lose its 
confidential character due to the passage of time, and (7) why 
disclosure of the information would be contrary to the public interest.
    It is DOE's policy that all comments may be included in the public 
docket, without change and as received, including any personal 
information provided in the comments (except information deemed to be 
exempt from public disclosure).
    DOE considers public participation to be a very important part of 
the process for developing test procedures and energy conservation 
standards. DOE actively encourages the participation and interaction of 
the public during the comment period in each stage of the rulemaking 
process. Interactions with and between members of the public provide a 
balanced discussion of the issues and assist DOE in the rulemaking 
process. Anyone who wishes to be added to the DOE mailing list to 
receive future notices and information about this rulemaking should 
contact Appliance and Equipment Standards Program staff at (202) 586-
6636 or via email at [email protected].

     Issued in Washington, DC, on July 11, 2017.
Kathleen B. Hogan,
Deputy Assistant Secretary for Energy Efficiency, Energy Efficiency and 
Renewable Energy.
[FR Doc. 2017-15580 Filed 7-24-17; 8:45 am]
BILLING CODE 6450-01-P