[Federal Register Volume 86, Number 99 (Tuesday, May 25, 2021)]
[Proposed Rules]
[Pages 28005-28012]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-10770]


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DEPARTMENT OF ENERGY

10 CFR Part 431

[EERE-2019-BT-TP-0027]
RIN 1904-AE65


Energy Conservation Program: Test Procedures for Packaged 
Terminal Air Conditioners and Packaged Terminal Heat Pumps

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

ACTION: Request for information.

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SUMMARY: The U.S. Department of Energy (``DOE'') is undertaking the 
preliminary stages of a rulemaking to consider amendments to the test 
procedures for Packaged Terminal Air Conditioners (``PTACs'') and 
Packaged Terminal Heat Pumps (``PTHPs'').
    Through this request for information (``RFI''), DOE seeks data and 
information regarding issues pertinent to whether amended test 
procedures would more accurately or fully comply with the requirement 
that the test procedure produces results that measure energy use during 
a representative average use cycle for the equipment without being 
unduly burdensome to conduct, or reduce testing burden. DOE welcomes 
written comments from the public on any subject within the scope of 
this document (including topics not raised in this RFI), as well as the 
submission of data and other relevant information.

DATES: Written comments and information are requested and will be 
accepted on or before June 24, 2021.

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 by email to the following address: 
[email protected]. Include ``Request for information'' and 
docket number EERE-2019-BT-TP-0027 and/or RIN number 1904-AE65 in the 
subject line of the message. Submit electronic comments in WordPerfect, 
Microsoft Word, PDF, or ASCII file format, and avoid the use of special 
characters or any form of encryption.
    Although DOE has routinely accepted public comment submissions 
through a variety of mechanisms, including the postal mail and hand 
delivery/courier, the Department has found it necessary to make 
temporary modifications to the comment submission process in light of 
the ongoing Covid-19 pandemic. DOE is accepting only electronic 
submissions at this time. If a commenter finds that this change poses 
an undue hardship, please contact Appliance Standards Program staff at 
(202) 586-1445 to discuss the need for alternative arrangements. Once 
the Covid-19 pandemic health emergency is resolved, DOE anticipates 
resuming all of its regular options for public comment submission, 
including postal mail and hand delivery/courier.
    No telefacsimiles (faxes) will be accepted. For detailed 
instructions on submitting comments and additional information on the 
rulemaking process, see section III of this document.
    Docket: The docket for this activity, which includes Federal 
Register notices, comments, and other supporting documents/materials, 
is available for review at https://

[[Page 28006]]

www.regulations.gov. All documents in the docket are listed in the 
https://www.regulations.gov index. However, some documents listed in 
the index, such as those containing information that is exempt from 
public disclosure, may not be publicly available.
    The docket web page can be found at https://www.regulations.gov/docket/EERE-2019-BT-TP-0027. The docket web page contains instructions 
on how to access all documents, including public comments, in the 
docket. See section III for information on how to submit comments 
through https://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Mr. Bryan Berringer, 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) 586-0371. Email: 
[email protected].
    Ms. Amelia Whiting, U.S. Department of Energy, Office of the 
General Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 
20585-0121. Telephone: (202) 586-2588. Email: 
[email protected].
    For further information on how to submit a comment or review other 
public comments and the docket, contact the Appliance and Equipment 
Standards Program staff at (202) 287-1445 or by email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction
    A. Authority and Background
    B. Rulemaking History
II. Request for Information
    A. Scope and Definitions
    B. Dehumidification of Fresh Air
    1. Market Size of Make-up Air PTACs and PTHPs
    2. Dehumidification Energy Use
    C. Part Load Efficiency Metric
    1. Market Size of PTACs and PTHPs With Part-Load Operation 
Capability
    2. Potential Part-Load Efficiency Metrics
    D. Fan-Only Mode
    E. Low Ambient Heating and Cold Climate Heat Pumps
III. Submission of Comments

I. Introduction

    PTACs and PTHPs are included in the list of ``covered equipment'' 
for which DOE is authorized to establish and amend energy conservation 
standards and test procedures. (42 U.S.C. 6311(1)(I)) DOE's test 
procedures for PTACs and PTHPs are prescribed at title 10 of the Code 
of Federal Regulations (``CFR''), subpart F of part 431. See 10 CFR 
431.96. The following sections discuss DOE's authority to establish and 
amend test procedures for PTACs and PTHPs, as well as relevant 
background information regarding DOE's consideration of test procedures 
for this equipment.

A. Authority and Background

    The Energy Policy and Conservation Act, as amended (``EPCA''),\1\ 
authorizes DOE to regulate the energy efficiency of a number of 
consumer products and certain industrial equipment. (42 U.S.C. 6291-
6317) Title III, Part C of EPCA,\2\ added by the National Energy 
Conservation Policy Act, Public Law 95-619 (Nov. 9, 1978), Title IV, 
section 441(a) (42 U.S.C. 6311-6317 as codified), established the 
Energy Conservation Program for Certain Industrial Equipment, which 
sets forth a variety of provisions designed to improve industrial 
equipment energy efficiency. The equipment addressed under these 
provisions includes PTACs and PTHPs, the subjects of this RFI. (42 
U.S.C. 6311(1)(I))
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    \1\ All references to EPCA in this document refer to the statute 
as amended through the Energy Act of 2020, Public Law 116-260 (Dec. 
27, 2020).
    \2\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
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    The energy conservation program under EPCA consists essentially of 
four parts: (1) Testing, (2) labeling, (3) Federal energy conservation 
standards, and (4) certification and enforcement procedures. Relevant 
provisions of EPCA include definitions (42 U.S.C. 6311), test 
procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315), 
energy conservation standards (42 U.S.C. 6313), and the authority to 
require information and reports from manufacturers (42 U.S.C. 6316).
    Federal energy efficiency requirements for covered equipment 
established under EPCA generally supersede State laws and regulations 
concerning energy conservation testing, labeling, and standards. (42 
U.S.C. 6316(a) and 42 U.S.C. 6316(b); 42 U.S.C. 6297). DOE may, 
however, grant waivers of Federal preemption for particular State laws 
or regulations, in accordance with the procedures and other provisions 
of EPCA. (42 U.S.C. 6316(b)(2)(D)).
    The Federal testing requirements consist of test procedures that 
manufacturers of covered equipment must use as the basis for: (1) 
Certifying to DOE that their equipment complies with the applicable 
energy conservation standards adopted pursuant to EPCA (42 U.S.C. 
6316(b); 42 U.S.C. 6296), and (2) making representations about the 
efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE uses 
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 criteria and procedures 
DOE must follow when prescribing or amending test procedures for 
covered equipment. EPCA requires that any test procedures prescribed or 
amended under this section must be reasonably designed to produce test 
results that reflect the energy efficiency, energy use or estimated 
annual operating cost of a given type of covered equipment during a 
representative average use cycle and requires that test procedures not 
be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))
    EPCA requires that the test procedures for PTACs and PTHPs 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''). (42 
U.S.C. 6314(a)(4)(A)) 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 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)(B) and 42 U.S.C. 6314(a)(4)(C))
    EPCA also requires that, at least once every 7 years, DOE review 
test procedures for all types of covered equipment, including PTACs and 
PTHPs, to determine whether amended test procedures would more 
accurately or fully comply with the requirements for the test 
procedures be reasonably designed to produce test results that reflect 
energy efficiency, energy use, and estimated operating costs during a 
representative average use cycle and to not be unduly burdensome to 
conduct. (42 U.S.C. 6314(a)(1)) In addition, if the Secretary 
determines that a test procedure amendment is warranted, the Secretary 
must publish proposed test procedures in the Federal Register, and 
afford interested persons an opportunity (of not less than 45 days' 
duration) to present oral and written data, views, and arguments on the 
proposed test procedures. (42 U.S.C. 6314(b)). If DOE

[[Page 28007]]

determines that test procedure revisions are not appropriate, DOE must 
publish its determination not to amend the test procedures. DOE is 
publishing this RFI to collect data and information to inform its 
decision in satisfaction of the 7-year review requirement specified in 
EPCA. (42 U.S.C. 6314(a)(1))

B. Rulemaking History

    On December 8, 2020, DOE published an early assessment review RFI 
in which it sought data and information pertinent to whether amended 
test procedures would (1) more accurately or fully comply with the 
requirement that the test procedure produces results that measure 
energy use during a representative average use cycle for the equipment 
without being unduly burdensome to conduct, or (2) reduce testing 
burden. See 85 FR 78967 (``December 2020 Early Assessment RFI''). DOE 
received comments in response to the December 2020 Early Assessment RFI 
from the interested parties listed in Table I.1. A parenthetical 
reference at the end of a comment quotation or paraphrase provides the 
location of the item in the public record.\3\
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    \3\ The parenthetical reference provides a reference for 
information located in DOE's test procedure rulemaking docket. 
(Docket No. EERE-2019-BT-TP-0027, which is maintained at https://www.regulations.gov/docket/EERE-2019-BT-TP-0027). The references are 
arranged as follows: (Commenter name, comment docket ID number, page 
of that document).

  Table I.1--Written Comments Received in Response to the December 2020
                          Early Assessment RFI
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                                   Reference in this
          Commenter(s)                   NOPR           Commenter type
------------------------------------------------------------------------
Appliance Standards Awareness     Joint Advocates...  Efficiency
 Project, American Council for                         Organizations.
 an Energy-Efficient Economy,
 Natural Resources Defense
 Council.
Air-Conditioning, Heating, and    AHRI..............  Trade Association.
 Refrigeration Institute.
California Investor-owned         CA IOUs...........  Utility
 Utilities.                                            Association.
GE Appliances...................  GEA...............  Manufacturer.
Northwest Energy Efficiency       NEEA..............  Efficiency
 Alliance.                                             Organization.
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    Based on DOE's review of the test procedures for PTACs and PTHPs 
and the comments received, as discussed in the following sections, DOE 
has determined it is appropriate to continue the test procedure 
rulemaking after the early assessment process. Specific comments are 
discussed in the sections that follow.

II. Request for Information

    In the following sections, DOE has identified a variety of issues 
on which it seeks input to determine whether, and if so how, an amended 
test procedure for PTACs and PTHPs would (1) more accurately or fully 
comply with the requirements in EPCA that test procedures be reasonably 
designed to produce test results which reflect energy use during a 
representative average use cycle, without being unduly burdensome to 
conduct, or (2) reduce testing burden. (42 U.S.C. 6314(a)(2))
    Additionally, DOE welcomes comments on any aspect of the existing 
test procedures for PTACs and PTHPs that may not specifically be 
identified in this document.

A. Scope and Definitions

    This RFI covers PTACs and PTHPs. ``Packaged terminal air 
conditioner'' is defined at 10 CFR 431.92 as a wall sleeve and a 
separate un-encased combination of heating and cooling assemblies 
specified by the builder and intended for mounting through the wall, 
and that is industrial equipment. It includes a prime source of 
refrigeration, separable outdoor louvers, forced ventilation, and 
heating availability by builder's choice of hot water, steam, or 
electricity. ``Packaged terminal heat pump'' is defined at 10 CFR 
431.92 as a packaged terminal air conditioner that utilizes reverse 
cycle refrigeration as its prime heat source, that has a supplementary 
heat source available, with the choice of hot water, steam, or electric 
resistant heat, and that is industrial equipment. Further, relevant to 
PTACs and PTHPs, DOE defines ``standard size'' to mean a packaged 
terminal air conditioner or packaged terminal heat pump with wall 
sleeve dimensions having an external wall opening of greater than or 
equal to 16 inches high or greater than or equal to 42 inches wide, and 
a cross-sectional area greater than or equal to 670 square inches. 10 
CFR 431.92. ``Non-standard size'' means a packaged terminal air 
conditioner or packaged terminal heat pump with existing wall sleeve 
dimensions having an external wall opening of less than 16 inches high 
or less than 42 inches wide, and a cross-sectional area less than 670 
square inches. Id.
    DOE notes that the current Federal test procedure and energy 
conservation standards at 10 CFR 431.96 and 431.97 apply to both 
standard size and non-standard size PTACs and PTHPs with cooling 
capacities less than 760,000 British thermal unit (``Btu'')/hour. 10 
CFR 431.96(b).
    Issue 1: DOE requests comment on the definitions of PTACs and PTHPs 
and whether any of the terms should be amended, and if so, how the 
terms should be amended. In particular, DOE requests comment on whether 
the terms are sufficient to identify which equipment is subject to the 
test procedure and whether any test procedure amendments are required 
to ensure that all such equipment can be appropriately tested in 
accordance with the test procedure.

B. Dehumidification of Fresh Air

    In a final rule published on July 21, 2015, DOE amended the energy 
conservation standards for PTACs and PTHPs. 80 FR 43161 (``July 2015 
Final Rule''). Comments offered during the public meeting conducted for 
development of the July 2015 Final Rule indicate that the majority of 
PTAC and PTHP units are installed in hotel applications.\4\ In hotel 
installations, the PTAC or PTHP unit provides cooling and heating to 
individual rooms or suites within the hotel; hotel hallways and common 
areas are usually serviced by a separate air conditioning system. In 
older building designs, fresh air ventilation is supplied to hotel 
rooms via the corridors to which the rooms are connected. In these 
designs, air is exhausted from each hotel room by a bathroom exhaust 
fan and is replaced by ``make-up'' air supplied via the corridor and 
conditioned by the heating, ventilation, and air conditioning 
(``HVAC'') system that serves the corridor. Make-up air from the 
corridor enters the hotel rooms by passing through an undercut or grill 
in the hotel room door.
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    \4\ See Docket No. EERE-2012-BT-STD-0029-0007 at p. 91.

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[[Page 28008]]

    Building designs that supply make-up air via corridors generally 
are no longer permissible under the building codes adopted in most U.S. 
states. Chapter 10, Section 1018.5 of the 2009 International Building 
Code (``IBC'') states that, with some exceptions, ``corridors shall not 
serve as supply, return, exhaust, relief or ventilation air ducts.'' 
\5\ The International Code Council (``ICC'') tracks the adoption of the 
IBC by state. The ICC reports that, as of January 2021, only seven 
states had not fully adopted the 2009 version or a more recent version 
of the IBC.\6\ These IBC code requirements have precipitated the 
introduction of PTAC and PTHP models that are designed to draw outdoor 
air into the unit, dehumidify the outdoor air, and introduce the 
dehumidified air into the conditioned space. These models are commonly 
referred to as ``make-up air PTACs'' or ``make-up air PTHPs.'' The 
following paragraphs discuss issues regarding the market size and 
energy consumption of make-up air PTACs and PTHPs.
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    \5\ International Code Council. 2009 International Building 
Code. Available at: https://codes.iccsafe.org/content/chapter/4641/.
    \6\ International Code Council (2021). ``International Codes--
Adoption by State.'' Available at: https://www.iccsafe.org/wp-content/uploads/Master-I-Code-Adoption-Chart-jan-2021.pdf.
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1. Market Size of Make-Up Air PTACs and PTHPs
    DOE has identified two different designs of make-up air PTAC and 
PTHP units on the market. In the first design, the PTAC or PTHP 
includes a dehumidifier module situated in the outdoor portion of the 
unit between the unit's outdoor heat exchanger and the panel that 
divides the indoor and outdoor portions of the unit. The dehumidifier 
module contains a compressor and refrigerant loop that are separate 
from the main refrigerant loop that the PTAC or PTHP uses to provide 
cooling to the conditioned space. In this design, outdoor air flows 
through the dehumidifier module, which removes moisture from the air, 
and into the conditioned space.
    In the second identified design, the make-up air PTAC or PTHP does 
not include a dehumidifier module. Instead, the unit incorporates a 
variable-speed compressor that can operate at speeds less than full 
speed. In this design, outdoor air is drawn through the unit and across 
the unit's primary evaporator coil; dehumidification is provided by the 
unit's main refrigerant loop; and the unit's variable-speed compressor 
adjusts its capacity to provide humidity control by matching compressor 
operation to the required load of sensible \7\ or latent \8\ cooling, 
such that the unit removes moisture from the air without cooling the 
air to a temperature well below the setpoint.
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    \7\ ``Sensible cooling'' refers to cooling that reduces air 
temperature without removing moisture from the air.
    \8\ ``Latent cooling'' refers to cooling that only removes 
moisture from the air.
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    In the December 2020 Early Assessment RFI, DOE requested 
information on the need for DOE's test procedure for PTACs and PTHPs to 
specify how to measure the energy use associated with dehumidification 
of make-up air; whether any existing industry test procedures may be 
used to measure the energy use associated with make-up air operation; 
and how make-up air operation relates to a representative average use 
cycle for PTACs and PTHPs. 85 FR 78967, 78969-78970.
    AHRI recommended that DOE not pursue changes to the test procedure 
to measure the energy use associated with dehumidification of make-up 
air, stating that the market for make-up air PTACs and PTHPs is very 
small (AHRI, No. 7 at p. 4). AHRI estimated that only a small fraction 
of PTACs/PTHPs sold include outdoor air capabilities and of these, an 
even smaller percentage include dehumidification capabilities. (Id.)
    The Joint Advocates stated that demand for make-up air units may be 
increasing (Joint Advocates, No. 4 at p. 1). The Joint Advocates cited 
marketing materials from two manufacturers that the Joint Advocates 
stated suggest an increase in the market for such equipment due to 
changes in the building codes and the purported cost benefits of such 
units. (Id.)
    DOE notes that while the market for make-up air PTACs and PTHPs may 
be small currently, the new IBC code requirements may lead to increased 
demand for these units. To better understand the current and future 
market for these make-up air units, DOE is requesting information on 
the following issues.
    Issue 2: DOE requests information on the market size for each of 
the PTAC and PTHP design options it has identified that provide 
dehumidification of fresh air.
    Issue 3: DOE requests information on any other design pathways by 
which a PTAC or PTHP can provide dehumidification of outdoor air and, 
if alternative designs exist, the market size of these alternative 
designs.
    Issue 4: DOE requests comment on how a ``make-up air PTAC'' and a 
``make-up air PTHP'' could be defined, and what characteristics could 
be used to distinguish make-up air PTACs and PTHPs from other PTACs and 
PTHPs.
2. Dehumidification Energy Use
    For PTACs and PTHPs, DOE currently specifies the energy efficiency 
ratio (``EER'') as the energy efficiency descriptor for cooling 
efficiency. Table 1 to 10 CFR 431.96. EER is the ratio of the produced 
cooling effect of the PTAC or PTHP to its net work input, expressed in 
Btu/watt-hour, and measured at standard rating conditions. 10 CFR 
431.92. For PTHPs, DOE specifies the coefficient of performance 
(``COP'') as the energy efficiency descriptor for heating efficiency. 
Table 1 to 10 CFR 431.96. COP is the ratio of the produced heating 
effect of the PTHP to its net work input, expressed in watts/watts, and 
measured at standard rating conditions. 10 CFR 431.92
    The test procedure for PTACs and PTHPs incorporates by reference 
certain provisions of the industry test standard AHRI Standard 310/380-
2014, ``Standard for Packaged Terminal Air-Conditioners and Heat 
Pumps'' (``AHRI Standard 310/380-2014''). 10 CFR 431.96(g). Neither the 
current DOE test procedure nor the industry test procedure, AHRI 
Standard 310/380-2014, account for any additional energy associated 
with the dehumidification of make-up air traversing the unit. When a 
unit is operating in cooling mode, the dehumidification function may 
add heat to the room, thus increasing the cooling load on the unit. In 
addition, introducing make-up air to the room while the unit is 
operating in heating mode could increase a unit's energy consumption if 
the unit uses electric resistance heating to heat the make-up air. The 
amount of energy consumed by a dehumidification function depends on a 
variety of factors, including the airflow rate, the amount of time the 
dehumidification function is engaged, how the dehumidification function 
is controlled, and the ambient air temperature, among others.
    As stated, EPCA requires that test procedures prescribed by DOE be 
reasonably designed to produce test results which reflect energy 
efficiency during a representative average use cycle, and must not be 
unduly burdensome to conduct. (42 U.S.C. 6314(a)(2)). In the December 
2020 Early Assessment RFI, DOE sought comment on make-up air operation 
as it relates to a representative average use cycle for PTACs and 
PTHPs. 85 FR 78967, 78970.
    AHRI commented that multiple factors would need to be considered in 
evaluating the operational use of make-

[[Page 28009]]

up units, such as the rate of airflow/CFM being brought into the indoor 
space from outside; whether the unit introduces the outside air as 
primary or supplementary air; and what dehumidification strategy was 
used (AHRI, No. 7 at p. 5-6). AHRI asserted that dehumidification of 
make-up air is not representative of an average use cycle for the vast 
majority of PTAC/PTHP equipment sold currently and will not contribute 
to significant energy consumption relative to the current EER and COP 
metrics. Id. at 6. AHRI noted the lack of an established test procedure 
that could be readily adopted to measure dehumidification associated 
with make-up air operation. Id. The Joint Advocates encouraged DOE to 
incorporate the additional energy use associated with PTACs and PTHPs 
that provide make-up air so that the test procedure is representative 
for these units (Joint Advocates, No. 4 at p. 1-2).
    DOE recognizes the challenges identified by AHRI regarding the 
evaluation of the make-up air operation. DOE requests information on 
the following issues.
    Issue 5: DOE requests data on the impacts on the energy consumption 
of PTACs and PTHPs that dehumidify incoming outdoor air for units that 
include a dehumidification module, a variable-speed compressor, or any 
other design that dehumidifies outdoor air and introduces it to the 
conditioned space, in both cooling and heating mode.
    Issue 6: DOE requests comment on how to quantify the energy 
consumption associated with the dehumidification function of make-up 
air PTACs/PTHPs for an average use cycle and what indoor and outdoor 
temperature and humidity conditions might be appropriate for this 
characterization.
    Issue 7: DOE requests data on the typical range of make-up air 
flowing through a make-up air PTAC/PTHP, and whether this airflow 
varies while the dehumidification function is engaged.
    Issue 8: DOE requests comment on how make-up air flowing through 
the unit is heated while the unit is operating in heating mode.
    Issue 9: DOE requests comment on how make-up air dehumidification 
is controlled for units with a dehumidifier module and units without a 
dehumidifier module. Specifically, what conditions trigger the unit to 
engage make-up air dehumidification and how do make-up air PTACs/PTHPs 
interact with variables like occupancy or exhaust fan controls.
    Issue 10: DOE requests data on the typical amount of time that 
make-up air PTACs/PHTPs engage the dehumidification function.
    Issue 11: DOE requests comment on how the cooling and 
dehumidification modes are coordinated for make-up air PTACs/PTHPs, 
whether dehumidification and cooling are typically performed 
simultaneously or separately, and the impact that any such coordination 
has on energy consumption.
    Issue 12: DOE requests data on the range of dehumidification 
capacities (in pints of water/day) for make-up air PTACs/PTHPs in the 
market and the test conditions used to rate dehumidification capacity.
    Issue 13: DOE requests data on the relative market share of make-up 
air PTACs/PTHPs within the three PTAC and PTHP capacity ranges: <7,000 
Btu/h; >=7,000 Btu/h and <=15,000 Btu/h; and >15,000 Btu/h.
    Issue 14: DOE requests comment on what instructions the test 
procedure should provide regarding how to prepare and setup a PTAC or 
PTHP makeup air unit for testing under the current DOE test procedure, 
which does not test the makeup air function of the unit.
Part Load Efficiency Metric
    As stated, EPCA requires the test procedures for PTACs and PTHPs be 
the generally accepted industry testing procedures developed or 
recognized by AHRI or ASHRAE, as referenced in ASHRAE Standard 90.1. 
(42 U.S.C. 6314(a)(4)(A)) EPCA also requires that test procedures 
prescribed by DOE be reasonably designed to produce test results which 
reflect energy efficiency during a representative average use cycle, 
and must not be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))
    For PTACs and PTHPs, ASHRAE 90.1-2019 specifies minimum efficiency 
levels expressed in terms of the full-load metrics of EER and COP. 
``Full-load'' refers to testing at a single test condition, under which 
the compressor is operated continuously at 100% of its full capacity. 
Full load performance is measured at the standard rating conditions in 
AHRI 310/380-2014. In contrast, for cooling, ``part-load'' refers to 
testing at a reduced-temperature test condition in which the cooling 
load of the space is less than the full cooling capacity of the 
compressor. Any temperatures below the standard rating condition could 
potentially be considered part-load cooling conditions. For heating, 
``part-load'' refers to testing at a higher-temperature test condition 
in which the heating load of the space is less than the full heating 
capacity of the compressor. Any temperatures above the standard rating 
condition could potentially be considered part-load heating conditions. 
DOE's test procedures for PTACs and PTHPs do not measure unit 
performance at part-load conditions.
    Under part-load operation, in which the cooling (or heating) load 
of the space is less than the full cooling (or heating) capacity of the 
compressor, a single-speed compressor cycles on and off. This cycling 
behavior introduces inefficiencies, i.e., ``cycling losses.'' More 
efficient part-load operation in PTACs and PTHPs can be enabled by the 
incorporation of two-stage, multi-stage, or variable-speed compressors, 
which can reduce or eliminate cycling losses.
3. Market Size of PTACs and PTHPs With Part-Load Operation Capability
    In the December 2020 Early Assessment RFI, DOE requested 
information on the need for DOE's test procedure for PTACs and PTHPs to 
specify how to measure the energy use associated with part-load 
operation; whether any existing industry test procedures may be used to 
measure the energy use associated with part-load operation; and how 
part-load operation relates to a representative average use cycle for 
PTACs and PTHPs. 85 FR 78967, 78969-78970.
    AHRI commented that very few PTACs or PTHPs with two- or variable-
speed compressors are on the market, and that with the vast majority of 
the current market being single stage products, a full-load metric is 
completely appropriate for these products (AHRI, No. 7 at p. 4). GEA 
asserted that moving the entire industry to a part-load metric would 
have little benefit to consumers and would have little or no effect on 
energy efficiency, while creating substantial cost and testing burden 
for industry (GEA, No. 6 at p. 2).
    The Joint Advocates and NEAA encouraged DOE to adopt an updated 
test procedure for PTACs and PTHPs that captures part-load performance 
(Joint Advocates, No. 4 at p. 2; NEEA, No. 8 at p. 1-2). CA IOUs 
commented that variable-speed compressors are now increasingly 
available and stated that this technology is expected to grow (CA IOUs, 
No. 5 at p. 2).
    DOE is aware of several variable-speed PTAC and PTHP models on the 
market. DOE is requesting more specific information on the market size 
of these models.
    Issue 15: DOE requests information on the market availability and 
market size for PTACs and PTHPs that incorporate

[[Page 28010]]

two-stage, multi-stage, or fully variable-speed compressors that enable 
more efficient part-load operation.
4. Potential Part-Load Efficiency Metrics
    To measure part-load performance, a part-load or seasonal 
efficiency metric for PTACs and PTHPs would need to be incorporated in 
the DOE test procedure. Several categories of air conditioning and 
heating equipment are already rated under DOE test procedures using 
metrics that account for part-load or seasonal performance. For 
example, commercial unitary air conditioners (``CUACs'') are rated 
using the part-load metric integrated energy efficiency ratio 
(``IEER'') (see appendix A to subpart F of part 431); and central air 
conditioners and heat pumps are rated using the seasonal energy 
efficiency ratio (``SEER'') (see appendix M to subpart B of 10 CFR part 
430). Room air conditioners are rated using the combined energy 
efficiency ratio (``CEER'').\9\ While the CEER metric is not a part-
load or seasonal metric, amendments to the DOE test procedure provide 
for the application of a performance adjustment factor to a variable-
speed model's CEER rating (i.e., ``performance-adjusted CEER'') that 
reflects seasonal efficiency benefits (see appendix F to subpart B of 
10 CFR part 430).\10\
---------------------------------------------------------------------------

    \9\ CEER is an energy efficiency metric for room air 
conditioners that integrates standby/inactive and off mode energy 
use with the active mode energy use. 10 CFR 430.23(f)(3); Appendix F 
to subpart V of 10 CFR part 430 section 2 and 5.2.2.
    \10\ DOE published a final rule on March 29, 2021 amending the 
test procedure for room air conditioners to establish test 
provisions for measuring the energy use of variable-speed units 
during a representative average use cycle. 86 FR 16446.
---------------------------------------------------------------------------

    In this RFI, DOE is requesting feedback on the appropriateness and 
potential applicability of these example part-load metrics for PTACs 
and PTHPs.
    PTACs and PTHPs may be considered as an alternative to CUACs in 
some applications. IEER (applicable to CUACs) integrates the 
performance of the equipment when operating at part-load, as discussed 
in section 6.2 of AHRI Standard 340/360-2019. CUACs rated with IEER are 
generally installed in buildings with high internal loads (e.g., 
offices, retail, restaurants, schools) resulting from electronic 
equipment and/or high occupant density. These high internal loads often 
require that CUACs operate in cooling mode even at low ambient outdoor 
air temperatures. IEER reflects seasonal performance by integrating 
test results from four different load points with varying outdoor 
conditions and load levels (i.e., lower load levels for cooler 
conditions) in order to represent the equipment's average efficiency 
throughout the cooling season (see appendix A to subpart F of 10 CFR 
part 431). DOE notes that most PTACs and PTHPs are installed in a 
narrow range of building types (including hotels, lodging, and assisted 
living). As such, the IEER load points and weighting factors developed 
for CUAC equipment may not represent typical operating conditions for 
PTACs and PTHPs.
    Products and equipment rated with SEER are generally used in 
residential or small commercial applications, often with smaller 
internal loads (in comparison to the internal loads of buildings 
typically served by CUAC equipment) that require minimal or no cooling 
at low ambient outdoor air temperatures. SEER (applicable to central 
air conditioning and heat pump systems) reflects seasonal performance 
by averaging test results from up to five different load points, 
depending on system configuration (single-speed, two-capacity, or 
variable-speed), with varying outdoor conditions and staging levels to 
represent the product's average efficiency throughout the cooling 
season (see appendix M to subpart B of 10 CFR part 430). The test 
procedure also includes optional cyclic testing to evaluate cycling 
losses.
    Room air conditioners and PTACs and PTHPs are both packaged air 
conditioning and heating equipment and have similar ranges of cooling 
capacity. Performance-adjusted CEER (applicable to room air 
conditioners with variable speed compressors) reflects the relative 
performance improvement associated with variable speed operation, in 
relation to theoretical single-speed operation, across four different 
outdoor temperature rating conditions (see appendix F to subpart B of 
10 CFR part 430). Products rated with CEER are typically used in 
residential or small commercial applications.
    Issue 16: DOE requests feedback on how to best measure part-load 
cooling performance for PTACs and PTHPs. Specifically, DOE requests 
comment on the number of tests that are appropriate to represent the 
part-load capabilities of the unit; the outdoor ambient conditions that 
best represent real world performance; the averaging weights that 
should be applied to each condition; whether a cyclic test component 
should be incorporated; and whether an optional test for multi-capacity 
rating should be incorporated.
    Issue 17: DOE requests feedback on whether IEER, SEER or 
performance-adjusted CEER would be appropriate metrics for PTACs and 
PTHPs.
    Issue 18: If IEER would be an appropriate metric, DOE requests 
information as to the outdoor temperature rating conditions appropriate 
for testing PTACs and PTHPs to produce test results representative of 
an average use cycle. DOE requests comment on what changes to the IEER 
test procedure for CUACs other that the temperature rating conditions 
would be necessary for testing PTACs and PTHPs. DOE requests 
information on the costs that would be associated with a test procedure 
that uses IEER as the metric for PTACs and PTHPs.
    Issue 19: If SEER would be an appropriate metric, DOE requests 
feedback on whether a test procedure for PTACs and PTHPs that uses SEER 
as the metric would produce test results that reflect the energy 
efficiency of that equipment during a representative average use cycle. 
DOE requests information on the costs that would be associated with a 
test procedure that uses SEER as the metric for PTACs and PTHPs.
    Issue 20: If performance-adjusted CEER would be an appropriate 
metric, DOE requests feedback on whether a test procedure for PTACs and 
PTHPs that uses performance-adjusted CEER as the metric would produce 
test results that reflect the energy efficiency of that equipment 
during a representative average use cycle. DOE requests information on 
the costs that would be associated with a test procedure that uses 
performance-adjusted CEER as the metric for PTACs and PTHPs.
    Issue 21: DOE requests comment on whether any other seasonal 
efficiency metrics that incorporate part-load performance would produce 
test results that reflect the energy efficiency of PTACs and PTHPs 
during a representative average use cycle, and if so, which outdoor 
temperature rating conditions would be appropriate for testing PTACs 
and PTHPs. DOE requests information on the costs that would be 
associated with use of any such metrics.
    Issue 22: DOE requests comment on whether the distribution and 
weighting of rating conditions used for the measurement of IEER, SEER, 
or performance-adjusted CEER would be appropriate for rating the 
performance of PTAC and PTHP equipment.
    DOE notes that, like the EER cooling metric, the COP heating metric 
measures performance only at full load operation. For the reasons 
described previously with regard to cooling efficiency, using a heating 
efficiency metric that accounts for only full-load operation does not 
measure the part-load operation in PTHPs that may be

[[Page 28011]]

enabled by the incorporation of two-stage, multi-stage, or variable-
speed compressors. Heating Season Performance Factor (``HSPF'') 
(applicable to central heat pump products) is a metric that serves as a 
counterpart to SEER and accounts for seasonal performance in the 
heating season. It reflects seasonal performance by averaging test 
results from multiple load points, depending on system configuration 
(single-speed, two-capacity, or variable-speed), with varying outdoor 
conditions and staging levels to represent the product's average 
efficiency throughout the heating season (see appendix M to subpart B 
of 10 CFR part 430).
    Issue 23: DOE requests feedback on how to best measure part-load 
and seasonal heating performance for PTHPs. Specifically, DOE requests 
comment on the number of tests that are appropriate to represent the 
part-load capabilities of the unit; the outdoor ambient conditions that 
best represent real world performance; the averaging weights that 
should be applied to each condition; whether a cyclic test component 
should be incorporated; whether an optional test for multi-capacity 
rating should be incorporated; and whether a test to evaluate the PTHP 
in defrost cycles is required.
    Issue 24: DOE requests feedback on whether HSPF would be an 
appropriate metric for PTHPs.
    Issue 25: DOE requests information on any other seasonal heating 
efficiency metrics that would produce test results that reflect the 
energy efficiency of PTHPs during a representative average use cycle, 
and if so, which outdoor temperature rating conditions would be 
appropriate for testing PTHPs.
    Issue 26: DOE requests information on the costs that would be 
associated with the use of any such seasonal heating efficiency metric 
to rate PTHP performance.

C. Fan-Only Mode

    In response to the December 2020 Early Assessment RFI, NEAA 
commented that DOE should account for ``fan-only'' mode, which NEEA 
asserted can account for a large number of annual hours, resulting in 
significant energy use (NEAA, No. 8 at p. 5). NEAA recommended that DOE 
assess the number of hours spent in fan-only mode and account for the 
energy used during these hours in the test procedure. Id.
    DOE interprets the ``fan-only'' mode discussed by NEAA as a mode in 
which the fan is operating and providing ventilation or air circulation 
without active cooling or heating. The current DOE test procedures for 
PTACs and PTHPs do not address energy consumption during ``fan-only'' 
mode. To better understand the power consumption associated with the 
``fan-only'' mode and how it relates to a representative average use 
cycle, DOE is requesting information on the following issues.
    Issue 27: DOE requests data and information related to the power 
consumption of PTAC and PTHP units during ``fan-only'' mode. 
Specifically, DOE requests comment on whether the indoor and outdoor 
fans are powered by the same source motor; whether the default fan 
control scheme dictates that the indoor fan cycles with the compressor 
or stays on; and whether the fan operates at a lower power if the fan 
remains on when the compressor cycles off.
    Issue 28: DOE requests data and information on the annual number of 
hours PTAC and PTHP units operate in ``fan-only'' mode.

D. Low Ambient Heating and Cold Climate Heat Pumps

    Heat pumps generally perform less efficiently at low ambient 
outdoor temperatures than they do at moderate ambient outdoor 
temperatures. DOE is aware of residential central heat pump models that 
are optimized for operation in cold climates and can operate at 
temperatures as low as -20 degrees Fahrenheit (``[deg]F''). DOE expects 
that such cold climate optimization may be desirable for PTHP 
customers, and DOE is aware of at least one PTHP model that is 
optimized for cold climates and can operate at temperatures as low as -
5 [deg]F.
    A conventional PTHP model switches its heat source from reverse-
cycle vapor compression heating to electric resistance heating, which 
is less efficient than vapor compression heating, at an outdoor ambient 
temperature of around 32 [deg]F. A PTHP design that is optimized for 
operation in cold climates could provide energy savings compared to 
conventional PTHP models by enabling the use of the more efficient 
vapor compression heating, rather than electric resistance heating, at 
lower ambient temperatures. However, DOE's current test metric for 
heating efficiency, COP, requires testing only at the standard rating 
condition of 47 [deg]F dry bulb for the outdoor side. Thus, DOE's COP 
metric does not account for the energy savings that could result from 
using reverse-cycle heating at low ambient temperatures.
    In response to the December 2020 Early Assessment RFI, the Joint 
Advocates and NEAA commented that DOE should consider updating the test 
procedure to capture performance of PTHPs at low ambient temperatures, 
including energy used in defrost (Joint Advocates, No. 4 at p. 2; NEAA, 
No. 8 at p. 4). The CA IOUs noted that AHRI 310/380-2004 specified 17 
[deg]F as the standard rating condition for low-temperature heat pump 
heating, but that this test point is no longer included in the 2014 or 
2017 versions of the standard (CA IOUs, No. 5 at p. 3).
    DOE requests further information on the prevalence of PTHPs that 
can operate at low temperatures, and any test methods that may be 
appropriate to account for low temperature performance.
    Issue 29: DOE request information on the comparison of the seasonal 
heating load and seasonable cooling load for a typical PTAC/PTHP 
installation.
    Issue 30: DOE requests information on the range of low-temperature 
cutout for compressor operation of PTHPs. Specifically, DOE requests 
information on the percentage of PTHPs that continue to operate the 
compressor at outdoor temperatures below 32 [deg]F, below 20 [deg]F, 
and below 10 [deg]F.
    Issue 31: DOE requests information on the design changes necessary 
for a typical PTHP (that has a 32 [deg]F low-temperature cutout) to be 
converted for satisfactory field performance operation at a 17 [deg]F 
outdoor test condition.
    Issue 32: DOE requests information on whether the design 
optimization of PTHPs for cold-climate operation impacts the COP as 
measured under the DOE test procedure.
    Issue 33: DOE requests that model numbers be provided to identify 
any PTHP units available in the market that are optimized for operation 
in cold climates.
    Issue 34: DOE requests feedback on any other test methods that 
would produce test results that reflect the energy efficiency of these 
units during a representative average use cycle, as well as information 
on the test burden associated with such test methods.

III. Submission of Comments

    DOE invites all interested parties to submit in writing by the date 
specified under the DATES heading, comments and information on matters 
addressed in this RFI and on other matters relevant to DOE's 
consideration of amended test procedures for PTACs and PTHPs. These 
comments and information will aid in the development of a test 
procedure NOPR for PTACs and PTHPs if DOE determines that amended test 
procedures may be appropriate for this equipment.
    Submitting comments via https://www.regulations.gov. The https://www.regulations.gov web page will

[[Page 28012]]

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 publicly viewable except for your 
first and last names, organization 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 technical 
difficulties and cannot contact you for clarification, DOE may not be 
able to consider your comment.
    However, your contact information will be publicly viewable if you 
include it in the comment or in any documents attached to your comment. 
Any information that you do not want to be publicly viewable should not 
be included in your comment, nor in any document attached to your 
comment. Following this instruction, persons viewing comments will see 
only first and last names, organization names, correspondence 
containing comments, and any documents submitted with the comments.
    Do not submit to https://www.regulations.gov information for which 
disclosure is restricted by statute, such as trade secrets and 
commercial or financial information (hereinafter referred to as 
Confidential Business Information (``CBI'')). Comments submitted 
through https://www.regulations.gov cannot be claimed as CBI. Comments 
received through the website will waive any CBI claims for the 
information submitted. For information on submitting CBI, see the 
Confidential Business Information section.
    DOE processes submissions made through https://www.regulations.gov 
before posting. Normally, comments will be posted within a few days of 
being submitted. However, if large volumes of comments are being 
processed simultaneously, your comment may not be viewable for up to 
several weeks. Please keep the comment tracking number that https://www.regulations.gov provides after you have successfully uploaded your 
comment.
    Submitting comments via email. Comments and documents submitted via 
email also will be posted to https://www.regulations.gov. If you do not 
want your personal contact information to be publicly viewable, do not 
include it in your comment or any accompanying documents. Instead, 
provide your contact information on a cover letter. Include your first 
and last names, email address, telephone number, and optional mailing 
address. The cover letter will not be publicly viewable as long as it 
does not include any comments.
    Include contact information each time you submit comments, data, 
documents, and other information to DOE. Faxes will not be accepted.
    Comments, data, and other information submitted to DOE 
electronically should be provided in PDF (preferred), Microsoft Word or 
Excel, WordPerfect, or text (ASCII) file format. Provide documents that 
are not secured, written in English and free of any defects or viruses. 
Documents should not contain special characters or any form of 
encryption and, if possible, they should carry the electronic signature 
of the author.
    Campaign form letters. Please submit campaign form letters by the 
originating organization in batches of between 50 to 500 form letters 
per PDF or as one form letter with a list of supporters' names compiled 
into one or more PDFs. This reduces comment processing and posting 
time.
    Confidential Business Information. According to 10 CFR 1004.11, any 
person submitting information that he or she believes to be 
confidential and exempt by law from public disclosure should submit via 
email 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. DOE will make its own 
determination about the confidential status of the information and 
treat it according to its determination.
    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 this process. 
Interactions with and between members of the public provide a balanced 
discussion of the issues and assist DOE in the process. Anyone who 
wishes to be added to the DOE mailing list to receive future notices 
and information about this process should contact Appliance and 
Equipment Standards Program staff at (202) 287-1445 or via email at 
[email protected].

Signing Authority

    This document of the Department of Energy was signed on May 15, 
2021, by Kelly Speakes-Backman, Principal Deputy Assistant Secretary 
and Acting Assistant Secretary for Energy Efficiency and Renewable 
Energy, pursuant to delegated authority from the Secretary of Energy. 
That document with the original signature and date is maintained by 
DOE. For administrative purposes only, and in compliance with 
requirements of the Office of the Federal Register, the undersigned DOE 
Federal Register Liaison Officer has been authorized to sign and submit 
the document in electronic format for publication, as an official 
document of the Department of Energy. This administrative process in no 
way alters the legal effect of this document upon publication in the 
Federal Register.

    Signed in Washington, DC, on May 15, 2021.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.
[FR Doc. 2021-10770 Filed 5-24-21; 8:45 am]
BILLING CODE 6450-01-P