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Rule2024-08543

Energy Conservation Program: Test Procedure for Air-Cooled, Evaporatively-Cooled, and Water-Cooled Commercial Package Air Conditioners and Heat Pumps

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Published

May 20, 2024

Effective

August 5, 2024

Issuing agencies

Energy Department

Abstract

The U.S. Department of Energy ("DOE") is amending the Federal test procedures for air-cooled commercial package air conditioners and heat pumps with a rated cooling capacity greater than or equal to 65,000 Btu/h, evaporatively-cooled commercial package air conditioners, and water-cooled commercial package air conditioners to incorporate by reference the latest versions of the applicable industry test standards. Specifically, DOE is amending the current test procedure for this equipment for measuring the current cooling and heating metrics--integrated energy efficiency ratio ("IEER") and coefficient of performance ("COP"), respectively; and establishing a new test procedure for this equipment that adopts two new metrics-- integrated ventilation, economizer, and cooling ("IVEC") and integrated ventilation and heating efficiency ("IVHE"). Testing to the IVEC and IVHE metrics will not be required until such time as compliance is required with any amended energy conservation standard based on the new metrics. Additionally, DOE is amending certain provisions of DOE's regulations related to representations and enforcement for the subject equipment.

Full Text

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[Federal Register Volume 89, Number 98 (Monday, May 20, 2024)]
[Rules and Regulations]
[Pages 43986-44049]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-08543]

[[Page 43985]]

Vol. 89

Monday,

No. 98

May 20, 2024

Part II

Department of Energy

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10 CFR Parts 429 and 431

Energy Conservation Program: Test Procedure for Air-Cooled,
Evaporatively-Cooled, and Water-Cooled Commercial Package Air
Conditioners and Heat Pumps; Final Rule

Federal Register / Vol. 89, No. 98 / Monday, May 20, 2024 / Rules and
Regulations

[[Page 43986]]

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2023-BT-TP-0014]
RIN 1904-AD93

Energy Conservation Program: Test Procedure for Air-Cooled,
Evaporatively-Cooled, and Water-Cooled Commercial Package Air
Conditioners and Heat Pumps

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

ACTION: Final rule.

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SUMMARY: The U.S. Department of Energy (``DOE'') is amending the
Federal test procedures for air-cooled commercial package air
conditioners and heat pumps with a rated cooling capacity greater than
or equal to 65,000 Btu/h, evaporatively-cooled commercial package air
conditioners, and water-cooled commercial package air conditioners to
incorporate by reference the latest versions of the applicable industry
test standards. Specifically, DOE is amending the current test
procedure for this equipment for measuring the current cooling and
heating metrics--integrated energy efficiency ratio (``IEER'') and
coefficient of performance (``COP''), respectively; and establishing a
new test procedure for this equipment that adopts two new metrics--
integrated ventilation, economizer, and cooling (``IVEC'') and
integrated ventilation and heating efficiency (``IVHE''). Testing to
the IVEC and IVHE metrics will not be required until such time as
compliance is required with any amended energy conservation standard
based on the new metrics. Additionally, DOE is amending certain
provisions of DOE's regulations related to representations and
enforcement for the subject equipment.

DATES: The effective date of this rule is August 5, 2024. The
amendments will be mandatory for testing the subject equipment starting
May 15, 2025.
The incorporation by reference of certain material listed in this
rule is approved by the Director of the Federal Register on August 5,
2024. The incorporation by reference of certain other materials listed
in this rule were approved by the Director of the Federal Register as
of January 22, 2016.

ADDRESSES: The docket, which includes Federal Register notices, public
meeting webinar attendee lists and transcripts, comments, and other
supporting documents/materials, is available for review at
<a href="http://www.regulations.gov">www.regulations.gov</a> under docket number EERE-2023-BT-TP-0014. All
documents in the docket are listed in the <a href="http://www.regulations.gov">www.regulations.gov</a> index.
However, not all documents listed in the index may be publicly
available, such as those containing information that is exempt from
public disclosure.
A link to the docket web page can be found at <a href="http://www.regulations.gov/docket/EERE-2023-BT-TP-0014">www.regulations.gov/docket/EERE-2023-BT-TP-0014</a>. The docket web page contains instructions
on how to access all documents, including public comments, in the
docket.
For further information on how to review the docket, contact the
Appliance and Equipment Standards Program staff at (202) 287-1445 or by
email: <a href="/cdn-cgi/l/email-protection#e0a190908c89818e8385b394818e8481928493b195859394898f8e93a08585ce848f85ce878f96">[email&#160;protected]</a>.

FOR FURTHER INFORMATION CONTACT: Mr. Troy Watson, 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: (240) 449-9387. Email:
<a href="/cdn-cgi/l/email-protection#115061617d78707f72744265707f75706375624064746265787e7f625174743f757e743f767e67">[email&#160;protected]</a>.
Mr. Eric Stas, U.S. Department of Energy, Office of the General
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121.
Telephone: (202) 586-4798. Email: <a href="/cdn-cgi/l/email-protection#387d4a515b166b4c594b785049165c575d165f574e">[email&#160;protected]</a>.
For further information on how to review the docket, contact the
Appliance and Equipment Standards Program staff at (202) 287-1445 or by
email: <a href="/cdn-cgi/l/email-protection#c889b8b8a4a1a9a6abad9bbca9a6aca9baacbb99bdadbbbca1a7a6bb88adade6aca7ade6afa7be">[email&#160;protected]</a>.

SUPPLEMENTARY INFORMATION: DOE maintains a previously approved
incorporation by reference and incorporates by reference the following
industry standards into parts 429 and 431:
AHRI Standard 340/360-2022 (I-P), 2022 Standard for Performance
Rating of Commercial and Industrial Unitary Air-conditioning and Heat
Pump Equipment, AHRI-approved January 26, 2022 (``AHRI 340/360-2022'').
AHRI Standard 1340-2023 (I-P), 2023 Standard for Performance Rating
of Commercial and Industrial Unitary Air-conditioning and Heat Pump
Equipment, AHRI-approved November 16, 2023 (``AHRI 1340-2023'').
Copies of AHRI 340/360-2022 and AHRI 1340-2023 can be obtained from
the Air-Conditioning, Heating, and Refrigeration Institute (``AHRI''),
2311 Wilson Blvd., Suite 400, Arlington, VA 22201, (703) 524-8800, or
online at: <a href="http://www.ahrinet.org/standards/search-standards">www.ahrinet.org/standards/search-standards</a>.
ANSI/ASHRAE Standard 37-2009, Methods of Testing for Rating
Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment,
ASHRAE-approved June 24, 2009 (``ANSI/ASHRAE 37-2009'').
Copies of ANSI/ASHRAE 37-2009 can be obtained from the American
Society of Heating, Refrigerating and Air-Conditioning Engineers
(``ASHRAE''), 180 Technology Parkway NW, Peachtree Corners, GA 30092,
(404) 636-8400, or online at: <a href="http://www.ashrae.org">www.ashrae.org</a>.
See section IV.N of this document for a further discussion of these
standards.

Table of Contents

I. Synopsis of the Final Rule
II. Authority and Background
A. Authority
B. Background
III. Discussion
A. Scope of Applicability
B. Definitions
1. CUAC and CUHP Definition
2. Basic Model Definition
3. Double-Duct Definition
4. Metric Definitions
C. Updates to Industry Standards
1. AHRI 340/360
2. AHRI 1340
3. ASHRAE 37
D. Term Sheet Recommendations and Metrics
1. IVEC
2. IVHE
E. DOE Adopted Test Procedures and Comments Received
1. Overall
2. Double-Duct Systems
3. ECUACs and WCUACs
a. Overall
b. ESP Requirements for ECUACs and WCUACs
c. ECUAC and WCUAC Test Temperatures and WCUAC Heat Rejection
Components
4. IVHE for Colder Climates
5. Test Conditions Used for Current Metrics in Appendix A
6. Test Conditions Used for New Metrics in Appendix A1
7. Provisions Introduced in the AHRI 1340-202X Draft
a. Cooling Weighting Factors Adjustment
b. ESP Testing Target Calculation
c. Test Instructions for Splitting ESP Between Return and Supply
Duct
d. Default Fan Power and Maximum Pressure Drop for Coil-Only
Systems
e. Component Power Measurement
f. Non-Standard Low-Static Indoor Fan Motors
g. IVHE Equations
8. Heating Test Provisions Not Included in the AHRI 1340-202X
Draft
a. General
b. Definitions of Heating Operating Levels
c. Boost2 Heating Operating Level and COP2<INF>5</INF>
d. Extrapolation of Boost Heating Operating Level to 21 [deg]F
e. Operating Levels Used for Optional COP2<INF>17</INF>
Representations
9. Test Procedure Revisions Recommended for a Future Rulemaking
F. Configuration of Unit Under Test
1. Summary
2. Background

[[Page 43987]]

3. Proposed Approach for Exclusion of Certain Components
a. Components Addressed Through Test Provisions of 10 CFR Part
431, Subpart F, Appendices A and A1
b. Components Addressed Through Representation Provisions of 10
CFR 429.43
c. Enforcement Provisions of 10 CFR 429.134
d. Testing Specially Built Units That Are Not Distributed in
Commerce
4. Updates in AHRI 1340-2023
5. Comments Received and Adopted Provisions
a. Overall Approach
b. Coated Coils
G. Represented Values
1. Cooling Capacity
a. Representations of Cooling Capacity
b. Verification of Cooling Capacity
2. AEDM Tolerance for IVEC and IVHE
3. Minimum Part-Load Airflow
H. Enforcement Procedure for Verifying Cut-In and Cut-Out
Temperatures
I. Organization of the Regulatory Text for CUACs and CUHPs
J. Effective and Compliance Dates
K. Test Procedure Costs and Impact
1. Appendix A
2. Appendix A1
IV. Procedural Issues and Regulatory Review
A. Review Under Executive Orders 12866, 13563, and 14094
B. Review Under the Regulatory Flexibility Act
1. Estimate of Small Entities Regulated
2. Description and Estimate of Compliance Requirements
a. Cost and Compliance Associated With Appendix A
b. Cost and Compliance Associated With Appendix A1
3. Significant Alternatives to the Rule
4. Certification Statement
C. Review Under the Paperwork Reduction Act of 1995
D. Review Under the National Environmental Policy Act of 1969
E. Review Under Executive Order 13132
F. Review Under Executive Order 12988
G. Review Under the Unfunded Mandates Reform Act of 1995
H. Review Under the Treasury and General Government
Appropriations Act, 1999
I. Review Under Executive Order 12630
J. Review Under Treasury and General Government Appropriations
Act, 2001
K. Review Under Executive Order 13211
L. Review Under Section 32 of the Federal Energy Administration
Act of 1974
M. Congressional Notification
N. Description of Materials Incorporated by Reference
V. Approval of the Office of the Secretary

I. Synopsis of the Final Rule

In this final rule, DOE updates its test procedures for CUACs and
CUHPs by: (1) updating the reference in the Federal test procedure to
the most recent version of the industry test procedure, AHRI 340/360-
2022, for measuring integrated energy efficiency ratio (``IEER''),
energy efficiency ratio (``EER''), and coefficient of performance
(``COP''), consistent with the latest version of ASHRAE Standard 90.1;
and (2) establishing a new test procedure that references a new
industry test procedure, AHRI 1340-2023, which is consistent with
recommendations from the ACUAC and ACUHP Working Group TP Term Sheet,
including ones for the adoption of new efficiency metrics (i.e.,
integrated ventilation, economizer, and cooling (``IVEC'') and
integrated ventilation and heating efficiency (``IVHE'')) and new
testing requirements.
To implement the changes, DOE is: (1) amending appendix A to
incorporate by reference AHRI 340/360-2022 for CUACs and CUHPs, while
maintaining the current efficiency metrics (i.e., EER, IEER, and COP);
and (2) adding a new appendix A1 to subpart F of 10 CFR part 431. At 10
CFR 431.96, ``Uniform test method for the measurement of energy
efficiency of commercial air conditioners and heat pumps,'' DOE is
listing appendix A1 as the applicable test method for CUACs and CUHPs
for any subsequent energy conservation standards denominated in terms
of IVEC and IVHE. Appendix A1 utilizes AHRI 1340-2023, including the
new IVEC and IVHE efficiency metrics recommended by the ACUAC and ACUHP
Working Group TP Term Sheet. Use of appendix A1 will not be required
until such time as compliance is required with any amended energy
conservation standard based on the new metrics, should DOE adopt such
standards. After the date on which compliance with appendix A1 is
required, appendix A will no longer be used as part of the Federal test
procedure. DOE is also amending certain provisions within DOE's
regulations for representation and enforcement consistent with the test
procedure amendments.
Table I-1 summarizes the adopted amendments to the DOE test
procedure for CUACs and CUHPs, the test procedure provision prior to
the amendment, and the reason for each adopted change.

[[Page 43988]]

[GRAPHIC] [TIFF OMITTED] TR20MY24.126

DOE has determined that the amendments to appendix A will not alter
the measured efficiency of CUACs and CUHPs or require retesting or
recertification solely as a result of DOE's adoption of the amendments
to the test procedure. Additionally, DOE has determined that the
amendments to appendix A will not increase the cost of testing.
Representations of energy use or energy efficiency will be required to
be based on testing in accordance with the amended test procedure in
appendix A beginning 360 days after the date of publication of this
test procedure final rule in the Federal Register.
DOE has determined that the new test procedure at appendix A1 will
alter the measured efficiency of CUACs and CUHPs and, as a result,
manufacturers would need to retest, or rerun the alternative efficiency
determination method where allowed, prior to making any representations
under the test procedure in appendix A1. Cost estimates for retesting
are discussed in section III.K of this document. As discussed, use of
appendix A1 will not be required until the compliance date of any
amended energy conservation standard denominated in terms of the new
metrics in appendix A1, should DOE adopt such standards.
The amendments to representation requirements in 10 CFR 429.43 will
not be required until either 360 days after publication in the Federal
Register of this test procedure final rule or beginning on the
compliance date of amended standards for CUACs and CUHPs based on IVEC
and IVHE (as applicable), depending on the specific provisions.
The effective date for the amended test procedures adopted in this
final rule is 75 days after publication of this document in the Federal
Register.

II. Authority and Background

Small, large, and very large commercial package air conditioning
and heating equipment 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)(B)-(D)) Commercial
package air conditioning and heating equipment includes as equipment
categories air-cooled commercial unitary air conditioners with a rated
cooling capacity greater than or equal to 65,000 Btu/h (``ACUACs'') and
air-cooled commercial unitary heat pumps with a rated cooling capacity
greater than or equal to 65,000 Btu/h (``ACUHPs''), evaporatively-
cooled commercial unitary air conditioners (``ECUACs''), and water-
cooled commercial unitary air conditioners (``WCUACs''), which are the
subject of this final rule.\1\ (ECUACs, WCUACs, ACUACs, and ACUHPs,
which includes double-duct equipment, are collectively referred to as
``CUACs and CUHPs'' in this document.) DOE's test procedures for CUACs
and CUHPs are currently prescribed at title 10 of the Code of Federal
Regulations (``CFR''), part 431, subpart F, Sec. 431.96, table 1. The
following sections discuss DOE's

[[Page 43989]]

authority to establish and amend test procedures for CUACs and CUHPs
and relevant background information regarding DOE's amendments to the
test procedures for this equipment.
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\1\ While ACUACs with a rated cooling capacity less than 65,000
Btu/h are included in the broader category of CUACs, they are not
addressed in this final rule. The test procedure for ACUACs with
rated cooling capacity less than 65,000 Btu/h have been addressed in
a separate rulemaking: see Docket No. EERE-2017-BT-TP-0031. All
references within this final rule to ACUACs and ACUHPs exclude
equipment with rated cooling capacity less than 65,000 Btu/h.
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A. Authority

The Energy Policy and Conservation Act, Public Law 94-163 (42
U.S.C. 6291-6317, as codified), as amended (``EPCA''),\2\ authorizes
DOE to regulate the energy efficiency of a number of consumer products
and certain industrial equipment. Title III, Part C \3\ of EPCA, added
by Public Law 95-619, Title IV, section 441(a), established the Energy
Conservation Program for Certain Industrial Equipment, which sets forth
a variety of provisions designed to improve energy efficiency. This
covered equipment includes small, large, and very large commercial
package air conditioning and heating equipment. (42 U.S.C. 6311(1)(B)-
(D)) Commercial package air conditioning and heating equipment includes
CUACs and CUHPs, the subject of this document.
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\2\ All references to EPCA in this document refer to the statute
as amended through the Energy Act of 2020, Public Law 116-260 (Dec.
27, 2020), which reflect the last statutory amendments that impact
Parts A and A-1 of EPCA.
\3\ 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), 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; 42
U.S.C. 6296).
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 other 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.
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 (b); 42 U.S.C. 6297) DOE may, however, grant waivers
of Federal preemption in limited circumstances for particular State
laws or regulations, in accordance with the procedures and other
provisions of EPCA. (42 U.S.C. 6316(b)(2)(D))
Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures
DOE must follow when prescribing or amending test procedures for
covered equipment. Specifically, EPCA requires that any test procedures
prescribed or amended under this section must be reasonably designed to
produce test results which reflect energy efficiency, energy use, or
estimated annual operating cost of a given type of covered equipment
(or class thereof) during a representative average use cycle (as
determined by the Secretary) and requires that such test procedures not
be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2)-(3))
EPCA generally requires that, at least once every seven years, DOE
evaluate test procedures for each type of covered equipment, including
CUACs and CUHPs, to determine whether amended test procedures would
more accurately or fully comply with the requirements for the test
procedures to not be unduly burdensome to conduct and be reasonably
designed to produce test results that reflect energy efficiency, energy
use, and estimated operating costs during a representative average use
cycle. (42 U.S.C. 6314(a)(1)-(3)) DOE refers to these provisions as the
``lookback'' provisions and rulemakings conducted under these
provisions as ``lookback'' rulemakings.
Specific to certain commercial equipment, including CUACs and
CUHPs, EPCA requires that the test procedures be those generally
accepted industry testing procedures or rating procedures developed or
recognized by AHRI or 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)) Further, 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, in which case DOE
may establish an amended test procedure that does satisfy those
statutory provisions. (42 U.S.C. 6314(a)(4)(B) and (C)) DOE refers to
these provisions as the ``ASHRAE trigger'' provisions and rulemakings
conducted under these provisions as ``ASHRAE trigger'' rulemakings. As
noted in the recent update to DOE's procedures, interpretations, and
policies for consideration of new or amended energy conservation
standards and test procedures, DOE considers an ASHRAE trigger to occur
only when ASHRAE Standard 90.1 is updated to include an amended
industry test procedure, and that referenced test procedure includes
amendments relative to the existing DOE test procedure. 89 FR 24340,
24351 (April 8, 2024).
Whether pursuant to the lookback provision or the trigger
provision, if DOE determines that a test procedure amendment is
warranted, the Department must publish proposed test procedures in the
Federal Register, and afford interested persons an opportunity (of not
less than 45 days duration) to present oral and written data, views,
and arguments on the proposed test procedures. (42 U.S.C. 6314(b)) If
DOE determines that test procedure revisions are not appropriate, DOE
must publish in the Federal Register its determination not to amend the
test procedures. (42 U.S.C. 6314(a)(1)(A)(ii))
DOE is publishing this final rule in satisfaction of its
aforementioned statutory obligations under EPCA. Specifically, in
accordance with the ASHRAE trigger provisions at 42 U.S.C.
6314(a)(4)(B), DOE is updating appendix A to reference the most recent
version of the industry test procedure, AHRI 340/360-2022, which was
adopted in ASHRAE Standard 90.1-2022, and which includes amendments
relative to the existing Federal test procedure at appendix A to
subpart F to 10 CFR part 431.\4\ Pursuant to section 6314(a)(4)(B), DOE
also evaluated whether AHRI 340/360-2022 could provide representative
results for the new efficiency metrics recommended by the Working Group
(i.e., IVEC and IVHE). While AHRI 340/360-2022 provides representative
results for the current energy efficiency metrics, IEER, EER, and COP,
it does not include, among other things, operating modes other than
mechanical-cooling-only operation in the cooling metric, part-load
heating tests, higher ESP requirements, or crankcase heater operation,
which are integral to the IVEC and IVHE metrics recommended

[[Page 43990]]

by the Working Group. A more complete discussion of the differences
between the current efficiency metrics and the IVEC and IVHE efficiency
metrics can be found in section III.D. Accordingly, as detailed below,
DOE has determined, supported by clear and convincing evidence, that
AHRI 340/360-2022 cannot provide representative energy use results for
the IVEC and IVHE efficiency metrics.
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\4\ As discussed in section I.B of this document, DOE was also
triggered by updated industry test procedures in ASHRAE Standard
90.1-2016 and ASHRAE Standard 90.1-2019, both of which included
amendments relative to the existing Federal test procedure. However,
ASHRAE Standard 90.1-2022, and its referenced industry test
procedure, AHRI 340/360-2022, supersedes these previous versions.
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As a result, consistent with 42 U.S.C. 6314(a)(4)(C), DOE is
establishing a new test procedure, appendix A1, to measure energy use
for the IVEC and IVHE efficiency metrics. DOE has determined that
appendix A1 is reasonably designed to reflect energy use for the IVEC
and IVHE efficiency metrics during a representative average use cycle
without being unduly burdensome to conduct. (See 42 U.S.C.
6314(a)(4)(C); id. section 6314 (a)(2)) In particular, DOE notes that
appendix A1 includes: (1) a more mathematically accurate representation
of cooling efficiency; (2) an integrated heating metric rather than the
single-point full-load COP metric, which includes performance at
multiple outdoor air temperatures as well as other operating modes not
previously accounted for in the COP metric (i.e., part-load heating,
heating-season ventilation hours, unoccupied no-load hours, and
supplemental electric resistance heat operation); (3) operating modes
other than mechanical-cooling-only operation in the cooling metric
(i.e., integrated mechanical and economizer cooling, economizer-only
cooling, cooling season ventilation, unoccupied no-load hours); (4)
higher external static pressure (``ESP'') requirements; (5) crankcase
heater operation; and (6) oversizing of units in field installations.
As DOE has determined that the updated version of the industry test
procedure, AHRI 340/360-2022, adopted in appendix A is more
representative than the previous version of the test procedure
referenced in appendix A (because it would more fully comply with the
requirements that the test procedure be not unduly burdensome to
conduct and be reasonably designed to produce test results that reflect
energy efficiency, energy use, and estimated operating costs during a
representative average use cycle) and because the test procedure
adopted in appendix A1 is more representative for the new IVEC and IVHE
metrics, this rulemaking also satisfies DOE's obligations under the
lookback provisions at 42 U.S.C. 6314(a)(1)(A). For more details on the
improved representativeness of AHRI 340/360-2022, see section III.E of
this document.

B. Background

DOE's existing test procedure for CUACs and CUHPs appears at 10 CFR
431.96 (Uniform test method for the measurement of energy efficiency of
commercial air conditioners and heat pumps). The test procedure for
ACUACs and ACUHPs with a rated cooling capacity of greater than or
equal to 65,000 Btu/h specified in 10 CFR 431.96 references appendix A
to subpart F of part 431 (``Uniform Test Method for the Measurement of
Energy Consumption of Air-Cooled Small (>=65,000 Btu/h), Large, and
Very Large Commercial Package Air Conditioning and Heating Equipment,''
referred to as ``appendix A'' in this document). Appendix A references
certain sections of ANSI/AHRI Standard 340/360-2007, ``2007 Standard
for Performance Rating of Commercial and Industrial Unitary Air-
Conditioning and Heat Pump Equipment,'' approved by ANSI on October 27,
2011 and updated by addendum 1 in December 2010 and addendum 2 in June
2011 (``ANSI/AHRI 340/360-2007''); ANSI/ASHRAE Standard 37-2009,
``Methods of Testing for Rating Electrically Driven Unitary Air-
Conditioning and Heat Pump Equipment'' (``ANSI/ASHRAE 37-2009''); and
specifies other test procedure requirements related to minimum external
static pressure (``ESP''), optional break-in period, refrigerant
charging, setting indoor airflow, condenser head pressure controls,
standard airflow and air quantity, tolerance on capacity at part-load
test points, and condenser air inlet temperature for part-load tests.
The DOE test procedure for ECUACs and WCUACs with a rated cooling
capacity of greater than or equal to 65,000 Btu/h specified in 10 CFR
431.96 incorporates by reference ANSI/AHRI 340/360-2007, excluding
section 6.3 of ANSI/AHRI 340/360-2007 and including paragraphs (c) and
(e) of 10 CFR 431.96.\5\ The DOE test procedure for ECUACs and WCUACs
with a rated cooling capacity of less than 65,000 Btu/h incorporates by
reference ANSI/AHRI Standard 210/240-2008, ``2008 Standard for
Performance Rating of Unitary Air-Conditioning & Air-Source Heat Pump
Equipment,'' approved by ANSI on October 27, 2011 and updated by
addendum 1 in June 2011 and addendum 2 in March 2012 (``ANSI/AHRI 210/
240-2008''), excluding section 6.5 of ANSI/AHRI 210/240-2008 and
including paragraphs (c) and (e) of 10 CFR 431.96.
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\5\ Paragraphs (c) and (e) of 10 CFR 431.96 address optional
break-in provisions and additional provisions regarding set-up,
respectively.
---------------------------------------------------------------------------

On October 26, 2016, ASHRAE published ASHRAE Standard 90.1-2016,
which included updates to the test procedure references for CUACs and
CUHPs (excluding CUACs and CUHPs with a rated cooling capacity less
than 65,000 Btu/h) to reference AHRI Standard 340/360-2015, ``2015
Standard for Performance Rating of Commercial and Industrial Unitary
Air-Conditioning and Heat Pump Equipment'' (``AHRI 340/360-2015'').\6\
This action by ASHRAE triggered DOE's obligations under 42 U.S.C.
6314(a)(4)(B), as outlined previously because AHRI 340/360-2015
included substantive changes compared to the current DOE test procedure
at appendix A to subpart F of 10 CFR part 431. On July 25, 2017, DOE
published a request for information (``RFI'') (``July 2017 TP RFI'') in
the Federal Register to collect information and data to consider
amendments to DOE's test procedures for certain categories of
commercial package air conditioning and heating equipment including
CUACs and CUHPs. 82 FR 34427.
---------------------------------------------------------------------------

\6\ The previous version of ASHRAE Standard 90.1 (i.e., ASHRAE
Standard 90.1-2013) references ANSI/AHRI 340/360-2007.
---------------------------------------------------------------------------

At the time DOE published the July 2017 TP RFI, the applicable
version of ASHRAE Standard 90.1 was the 2016 edition, which referenced
AHRI Standard 340/360-2015, ``2015 Standard for Performance Rating of
Commercial and Industrial Unitary Air-Conditioning and Heat Pump
Equipment'' as the test procedure for CUACs and CUHPs. However, on
October 24, 2019, ASHRAE published ASHRAE Standard 90.1-2019, which
updated the relevant AHRI Standard 340/360 reference to the 2019
edition, ``2019 Standard for Performance Rating of Commercial and
Industrial Unitary Air-Conditioning and Heat Pump Equipment'' (``AHRI
340/360-2019''). This action by ASHRAE again triggered DOE's
obligations under 42 U.S.C. 6314(a)(4)(B), as outlined previously,
because AHRI 340/360-2019 included substantive changes compared to the
current DOE test procedure at appendix A to subpart F of 10 CFR part
431. In January 2022, AHRI published additional updates to its test
procedure standard for CUACs and CUHPs, with the publication of AHRI
Standard 340/360-2022, ``2022 Standard for Performance Rating of
Commercial and Industrial Unitary Air-conditioning and Heat Pump
Equipment'' (``AHRI 340/360-2022''), which DOE references in

[[Page 43991]]

the amended test procedure in appendix A to subpart F of 10 CFR part
431, as established in this final rule.
For ECUACs and WCUACs with a rated cooling capacity less than
65,000 Btu/h, ASHRAE Standard 90.1-2016 references ANSI/AHRI 210/240-
2008, which is referenced by the current Federal test procedure at 10
CFR 431.96 for this equipment. After the publication of the July 2017
RFI, AHRI published AHRI Standard 210/240-2017, ``2017 Standard for
Performance Rating of Unitary Air-conditioning & Air-source Heat Pump
Equipment'' (``AHRI 210/240-2017''). ASHRAE Standard 90.1-2019 updated
its reference to AHRI 210/240-2017 as the test procedure for ECUACs and
WCUACs with rated cooling capacities less than 65,000 Btu/h. This
action by ASHRAE triggered DOE's obligations under 42 U.S.C.
6314(a)(4)(B), as outlined previously, because AHRI 210/240-2017
included substantive changes compared to the current DOE test procedure
for ECUACs and WCUACs with a rated cooling capacity less than 65,000
Btu/h at 10 CFR 431.96. However, after the publication of AHRI 210/240-
2017, AHRI released two updates to that industry standard: (1) AHRI
Standard 210/240-2017 with Addendum 1, ``2017 Standard for Performance
Rating of Unitary Air-conditioning & Air-source Heat Pump Equipment''
(``AHRI 210/240-2017 with Addendum 1''), which was published in April
2019; and (2) AHRI Standard 210/240-2023, ``2023 Standard for
Performance Rating of Unitary Air-conditioning & Air-source Heat Pump
Equipment'' (``AHRI 210/240-2023''), which was published in May
2020.\7\
---------------------------------------------------------------------------

\7\ AHRI 210/240-2023 notes at the beginning of the standard
that while it was first published in May 2020, it establishes a
method to rate residential central air conditioners and heat pumps
consistent with the Federal test procedure for residential central
air conditioners and heat pumps codified in 10 CFR part 430, subpart
B, appendix M1 (``appendix M1''). Appendix M1 was required to be
used coincident with the January 1, 2023 compliance date of Federal
energy conservation standards denominated in terms of seasonal
energy efficiency ratio 2 (``SEER2''), energy efficiency ratio 2
(``EER2''), and heating seasonal performance factor 2 (``HSPF2'').
Therefore, despite being published in May 2020, this version was
named AHRI 210/240-2023.
---------------------------------------------------------------------------

On May 12, 2020, DOE published an RFI in the Federal Register
regarding energy conservation standards for ACUACs, ACUHPs, and
commercial warm air furnaces (``May 2020 ECS RFI''). 85 FR 27941. In
response to the May 2020 ECS RFI, DOE received comments from various
stakeholders, including ones related to the test procedure for ACUACs
and ACUHPs.
On May 25, 2022, DOE published an RFI in the Federal Register
regarding test procedures and energy conservations standards for CUACs
and CUHPs (``May 2022 TP/ECS RFI''). 87 FR 31743.
On July 29, 2022, DOE published in the Federal Register a notice of
intent to establish a working group for commercial unitary air
conditioners and heat pumps (``Working Group'') to negotiate proposed
test procedures and amended energy conservation standards for this
equipment (``July 2022 Notice of Intent''). 87 FR 45703. The Working
Group was established under the Appliance Standards and Rulemaking
Federal Advisory Committee (``ASRAC'') in accordance with the Federal
Advisory Committee Act (FACA) (5 U.S.C. App 2) and the Negotiated
Rulemaking Act (``NRA'') (5 U.S.C. 561-570, Pub. L. 104-320). The
purpose of the Working Group was to discuss, and if possible, reach
consensus on recommended amendments to the test procedures and energy
conservation standards for ACUACs and ACUHPs. The Working Group
consisted of 14 voting members, including DOE. (See appendix A, Working
Group Members, to Document No. 65 in Docket No. EERE-2022-BT-STD-0015)
On December 15, 2022, the Working Group signed a term sheet of
recommendations regarding ACUAC and ACUHP test procedures to be
submitted to ASRAC, the contents of which are referenced throughout
this final rule (referred to hereafter as the ``ACUAC and ACUHP Working
Group TP Term Sheet''). (See Id.) The ACUAC and ACUHP Working Group TP
Term Sheet was approved by ASRAC on March 2, 2023. These
recommendations are discussed further in section III.D of this final
rule.
In January 2023, ASHRAE published ASHRAE Standard 90.1-2022, which
included updates to the test procedure references for CUACs and CUHPs
with cooling capacities greater than or equal to 65,000 Btu/h,
specifically referencing AHRI 340/360-2022. For ECUACs and WCUACs with
capacities less than 65,000 Btu/h, ASHRAE Standard 90.1-2022 references
AHRI 210/240-2023. Notably, ECUACs and WCUACs with a rated cooling
capacity less than 65,000 Btu/h were removed from the scope of AHRI
210/240-2023 and are instead included in the scope of AHRI 340/360-
2022.\8\ DOE discusses this change in scope to the industry test
procedure and comments received related to ECUACs and WCUACs with a
cooling capacity less than 65,000 Btu/h in section III.E.3 of this
final rule. These actions by ASHRAE again triggered DOE's obligations
under 42 U.S.C. 6314(a)(4)(B) for ACUACs and ACUHPs, as outlined
previously, because AHRI 340/360-2022 again included substantive
changes compared to the current DOE test procedure at appendix A to
subpart F of 10 CFR 431. While DOE was triggered previously with the
publication of ASHRAE 90.1-2016 and ASHRAE 90.1-2019, the latest
version, ASHRAE 90.1-2022, and its referenced industry test procedure,
AHRI 340/360-2022, supersedes these previous versions. Therefore, in
this final rule DOE evaluated the amendments under ASHRAE 90.1-2022
(i.e., AHRI 340/360-2022) relative to the current Federal test
procedures for the CUACs and CUHPs.
---------------------------------------------------------------------------

\8\ ECUACs and WCUACs with a rated cooling capacity greater than
or equal to 65,000 Btu/h are included in the scope of ANSI/AHRI 340/
360-2007 and continue to be included in scope of the latest version
of AHRI 340/360 (i.e., AHRI 340/360-2022).
---------------------------------------------------------------------------

DOE published a notice of proposed rulemaking (``NOPR'') in the
Federal Register on August 17, 2023, presenting DOE's proposals to
amend the CUAC and CUHP test procedure (``August 2023 TP NOPR''). 88 FR
56392. The August 2023 TP NOPR also summarized and responded to
comments pertaining to test procedures for CUACs and CUHPs received in
response to the July 2017 TP RFI, the May 2020 ECS RFI, and the May
2022 TP/ECS RFI. Id. DOE held a public webinar related to the August
2023 TP NOPR on September 7, 2023 (hereafter, the ``NOPR public
webinar'').
DOE received comments in response to the August 2023 TP NOPR from
the interested parties listed in Table II-1, along with each
commenter's abbreviated name used throughout this final rule.
Discussion of relevant comments and DOE's responses are provided in
appropriate sections of this document.

[[Page 43992]]

[GRAPHIC] [TIFF OMITTED] TR20MY24.127

A parenthetical reference at the end of a comment quotation or
paraphrase provides the location of the item in the public record.\9\
To the extent that interested parties have provided written comments
that are substantively consistent with any oral comments provided
during the September 7, 2023 NOPR public webinar, DOE cites the written
comments throughout this final rule. DOE did not identify any oral
comments provided during the NOPR public webinar that are not
substantively addressed by written comments.
---------------------------------------------------------------------------

\9\ The parenthetical reference provides a reference for
information located in the docket of DOE's rulemaking to develop
test procedures for CUACs and CUHPs. (Docket No. EERE-2023-BT-TP-
0014, which is maintained at <a href="http://www.regulations.gov">www.regulations.gov</a>) The references are
arranged as follows: (commenter name, comment docket ID number, page
of that document).
---------------------------------------------------------------------------

In response to the August 2023 TP NOPR, DOE received multiple
comments regarding energy conservation standards for CUACs and CUHPs,
particularly regarding standards for ECUACs, WCUACs, and double-duct
systems. Comments regarding energy conservation standards are outside
the scope of consideration for this test procedure rulemaking and are
not addressed in this final rule. Topics related to energy conservation
standards for CUACs and CUHPs would be addressed in separate rulemaking
processes.
Following the publication of the August 2023 TP NOPR, AHRI
published AHRI Standard 1340-2023, ``2023 Standard for Performance
Rating of Commercial and Industrial Unitary Air-conditioning and Heat
Pump Equipment'' (``AHRI 1340-2023''). This is an update to AHRI
Standard 340/360 that incorporates the recommendations in the ACUAC and
ACUHP Working Group TP Term Sheet. This updated industry standard has
not yet been adopted in ASHRAE Standard 90.1, and as such does not
constitute an ASHRAE trigger, as outlined previously.

III. Discussion

In the following sections, DOE outlines certain amendments to its
test procedures for CUACs and CUHPs. For each amendment, DOE provides
relevant background information, explains why the amendment is
necessary, discusses relevant public comments, and discusses the
approach DOE has implemented.

A. Scope of Applicability

This rulemaking applies to ACUACs and ACUHPs with a rated cooling
capacity greater than or equal to 65,000 Btu/h, including double-duct
air conditioners and heat pumps, as well as ECUACs and WCUACs of all
capacities. Definitions that apply to CUACs and CUHPs are discussed in
section III.B of this final rule.
DOE's regulations for CUACs and CUHPs cover both single-package
units and split systems. See the definition of ``commercial package
air-conditioning and heating equipment'' at 10 CFR 431.92. A split
system consists of a condensing unit--which includes a condenser coil,
condenser fan and motor, and compressor--that is paired with a separate
component that includes an evaporator coil to form a complete
refrigeration circuit for space conditioning. One application for

[[Page 43993]]

condensing units is to be paired with an air handler (which includes an
evaporator coil), such that the combined system (i.e., the condensing
unit with air handler) meets the definition of a split system CUAC or
CUHP. It should be pointed out that AHRI has a certification program
for unitary large equipment that includes certification of CUACs,
CUHPs, and condensing units. DOE notes that as part of the AHRI
certification program for unitary large equipment, manufacturers who
sell air-cooled condensing units with a rated cooling capacity greater
than or equal to 65,000 Btu/h and less than 135,000 Btu/h must certify
condensing units as a complete system (i.e., paired with an air
handler) according to the AHRI 340/360 test procedure.\10\ However, for
condensing units with a rated cooling capacity greater than or equal to
135,000 Btu/h and less than 250,000 Btu/h, the AHRI certification
program allows manufacturers to certify condensing units as a complete
system according to AHRI 340/360 or optionally certify as a condensing
unit only according to AHRI Standard 365, ``Standard for Performance
Rating of Commercial and Industrial Unitary Air-Conditioning Condensing
Units'' (``AHRI 365'').
---------------------------------------------------------------------------

\10\ See appendix A of the AHRI Unitary Large Equipment
Certification Program Operations Manual (January 2024). This can be
found at <a href="http://www.ahrinet.org/system/files/2023-10/ULE_OM.pdf">www.ahrinet.org/system/files/2023-10/ULE_OM.pdf</a>.
---------------------------------------------------------------------------

In the August 2023 TP NOPR, DOE emphasized that these AHRI testing
and certification requirements differ from the Federal test procedure
at 10 CFR 431.96, which requires testing to ANSI/AHRI 340/360-2007 and
does not permit certifying to DOE as a condensing unit only according
to AHRI 365. 88 FR 56392, 56398-56399 (August 17, 2023). Additionally,
the AHRI certification program does not include unitary split systems
or condensing units with cooling capacities above 250,000 Btu/h,
whereas the Federal test procedure and standards (codified at 10 CFR
431.96 and 431.97, respectively) cover all CUACs and CUHPs with cooling
capacities up to 760,000 Btu/h. Once again, in the August 2023 TP NOPR,
DOE emphasized that condensing unit models distributed in commerce with
air handlers with cooling capacities up to 760,000 Btu/h are covered as
commercial package air-conditioning and heating equipment (see
definition at 10 CFR 431.92), and as such, they are subject to the
Federal regulations specified for CUACs and CUHPs regarding test
procedures (10 CFR 431.96), energy conservation standards (10 CFR
431.97), and certification and representation requirements (10 CFR
429.43). 88 FR 56392, 56398-56399 (August 17, 2023).
In response to the August 2023 TP NOPR, DOE received several
comments regarding DOE's clarification of coverage of condensing units.
Trane commented that single-package and split-system equipment are
included in the DOE regulation, but stated that the AHRI certification
program structure specific to split systems exists for several reasons.
(Trane, No. 14 at p. 2) Trane stated that split systems between 65,000
Btu/h and 250,000 Btu/h are often matched sets, but split systems
between 135,000 Btu/h to 250,000 Btu/h may be installed in applications
where a stand-alone condenser is matched in the field with a non-
matched air-handling unit, which Trane commented warrants a separate
stand-alone condenser rating. Trane stated that in larger split-system
applications (with capacities greater than 250,000 Btu/h) condensing
units are often paired with: (1) semi-custom and custom air-handling
units that are unique to that installation; (2) more than one air-
handling unit, or (3) air-handling units manufactured by different HVAC
manufacturers, or the system is built up in the field and all controls
for the system are installed on site. Trane asserted that even
considering only the air handlers offered by a single manufacturer,
there would be thousands of condenser and air handler combinations that
would require testing, alternative efficiency determination method
(``AEDM'') development, and certification. Trane also stated that in
split-system replacements, condensing units are often replaced more
frequently than the air-handling unit. Id.
AHRI commented that certifying condensing units as a complete
system (paired with an air handler) is appropriate for the capacity
range between 65,000 and 135,000 Btu/h, but that rating models with
capacities greater than or equal to 135,000 Btu/h as either a complete
system (using AHRI 340/360) or as a condensing unit only (using AHRI
365) allows manufacturers to provide condensing units for installation
in a system that may be connected to a number of different indoor
equipment types. (AHRI, No. 15 at pp. 4-5) AHRI commented that using
AHRI 365 to rate models allows manufacturers to meet customer needs
when indoor equipment and controls with which the condensing unit would
be paired in the field are not known. AHRI stated that there is no
procedure in AHRI 340/360 nor AHRI 1340 for rating outdoor units such
as condensing units without an indoor match. Furthermore, AHRI
commented that DOE had not investigated the impact of this proposed
change sufficiently and asserted that there could be serious
consequences. Id.
In response to concerns raised by AHRI and Trane, DOE emphasizes
that the clarification provided in the August 2023 TP NOPR regarding
the coverage of condensing units paired with air handlers is not a
change from the existing requirements for rating these models. Neither
the current DOE test procedure nor the amended test procedures adopted
in this final rule reference AHRI 365 for testing or rating condensing
units only. Accordingly, in this final rule, DOE reiterates that
condensing unit models distributed in commerce with air handlers with
cooling capacities up to 760,000 Btu/h are covered as commercial
package air-conditioning and heating equipment (see definition at 10
CFR 431.92), and as such, they are subject to the Federal regulations
specified for CUACs and CUHPs regarding test procedures (10 CFR
431.96), energy conservation standards (10 CFR 431.97), and
certification and representation requirements (10 CFR 429.43).
Regarding Trane's assertion as to the extent of testing, AEDM
development, and certification needed, DOE notes that its regulations
do not require that ratings for CUACs and CUHPs (including split
systems that comprise a condensing unit and air handler) be developed
through testing, and that AEDMs can be used to rate all such systems.
DOE further notes that to the extent that manufacturers have developed
simulations of condensing unit model performance in accordance with
AHRI 365, such simulations could be used as the basis of an AEDM to
rate condensing units paired with air handlers, provided the AEDM
satisfies the minimum requirements specified at 10 CFR 429.70(c).

B. Definitions

1. CUAC and CUHP Definition
As in this final rule, DOE has previously used the colloquial terms
``commercial unitary air conditioners'' and ``commercial unitary heat
pump'' (i.e., CUACs and CUHPs), to refer to certain commercial package
air conditioning and heating equipment, recognizing that CUAC is not a
statutory term and is not currently used in the CFR. See 79 FR 58948,
58950 (Sept. 30, 2014); 80 FR 52676, 52676 (Sept. 1, 2015). As codified
in regulation, the classes for which EPCA prescribed standards have
been grouped under the headings ``commercial air conditioners

[[Page 43994]]

and heat pumps'' (10 CFR 431.96(b), table 1) and ``air conditioning and
heating equipment'' (10 CFR 431.97(b), table 1), although these are not
defined terms. These classes have also been identified by the broader
equipment type with which they are associated (i.e., small, large, or
very large commercial package air conditioning and heating equipment).
Id.
In the August 2023 TP NOPR, DOE proposed to establish a definition
for ``commercial unitary air conditioner and commercial unitary heat
pump'' to assist in distinguishing between the regulated categories of
commercial package air conditioning and heating equipment. 88 FR 56392,
56399-56400 (August 17, 2023). The proposed definition was structured
to indicate categories of commercial package air conditioning and
heating equipment that are excluded from the definition, rather than
stipulating features or characteristics of CUACs and CUHPs. The
proposed definition excluded single package vertical air conditioners
and heat pumps (``SPVUs''), variable refrigerant flow multi-split air
conditioners and heat pumps, and water-source heat pumps. Specifically,
DOE proposed to define ``commercial unitary air conditioner and
commercial unitary heat pump'' as any small, large, or very large air-
cooled, water-cooled, or evaporatively-cooled commercial package air
conditioning and heating equipment that consists of one or more
factory-made assemblies that provide space conditioning; but does not
include: (1) single package vertical air conditioners and heat pumps;
(2) variable refrigerant flow multi-split air conditioners and heat
pumps; (3) water-source heat pumps; (4) equipment marketed only for use
in computer rooms, data processing rooms, or other information
technology cooling applications, and (5) equipment only capable of
providing ventilation and conditioning of 100-percent outdoor air
marketed only for ventilation and conditioning of 100-percent outdoor
air. Id. at 88 FR 56399. DOE also requested comment on the proposed
definition for ``commercial unitary air conditioners and heat pumps.''
Id. at 88 FR 56400.
DOE received feedback from several commenters regarding the
proposed definition for CUACs and CUHPs. AHRI, Rheem, and Trane
commented that they did not agree that the proposed definition for
CUACs and CUHPs is necessary or addresses any existing problems. (AHRI,
No. 15 at p. 3; Rheem, No. 12 at pp. 1-2; Trane, No. 14 at p. 3) AHRI
asserted that manufacturers, regulators, and design engineers
understand the phrase ``unitary central air conditioners and central
air-conditioning heat pumps for commercial application'' within the
existing definition for ``commercial package air-conditioning and
heating equipment'' as referring to CUACs and CUHPs. (AHRI, No. 15 at
p. 3) AHRI also stated that the proposed definition for CUACs and CUHPs
creates a circular reference to the existing definition of ``Commercial
package air-conditioning and heating equipment.'' (Id.) AHRI further
asserted that the proposed definition for CUACs and CUHPs should not be
implemented, as the term is not referenced (or proposed) in 42 U.S.C.
6311. (Id at p. 4) AHRI did not support any changes that would separate
small, large, or very large commercial package air conditioning and
heating equipment from their designation as ``ASHRAE equipment'' per 42
U.S.C. 6313. (Id.)
Carrier, NEEA, and NYSERDA supported the proposed definition of
``commercial unitary air conditioner and commercial unitary heat
pump.'' (Carrier, No. 8 at pp. 1-2; NEEA, No. 16 at pp. 3-4; NYSERDA,
No. 13 at p. 3) Carrier recommended DOE also adopt the definitions for
``Commercial and Industrial Unitary Air-Conditioning Equipment'' and
``Commercial and Industrial Unitary Heat Pump'' in sections 3.4 and 3.5
of AHRI 340/360-2022 and sections 3.5 and 3.6 of AHRI 1340-202X Draft
to provide additional clarity. (Carrier, No. 8 at pp. 1-2) NYSERDA
recommended including ``packaged or split'' in the definition for
additional clarity. (NYSERDA, No. 13 at p. 3)
NEEA also commented that the definition proposed for CUACs and
CUHPs includes excluded products, which appeared contradictory to DOE's
statement that models can meet the definition for multiple equipment
categories. (NEEA, No. 16 at pp. 3-4) NEEA requested clarification
regarding DOE's intent with the proposed definition. (Id.) AHRI also
requested clarification as to why DOE used distinct descriptions for
the fourth and fifth exclusions in the proposed CUAC and CUHP
definition rather than using the already defined terms in 10 CFR
431.92, ``Computer room air conditioners,'' and ``Unitary dedicated
outdoor air systems'' respectively. (AHRI, No. 15 at pp. 3-4)
After consideration of the comments received and upon further
review, DOE is declining to finalize the proposed definition for CUACs
and CUHPs in this final rule. DOE may consider adopting a definition
for CUACs and CUHPs in a future rulemaking action.
2. Basic Model Definition
The current definition for ``basic model'' in DOE's regulations
includes a provision applicable for ``small, large, and very large air-
cooled or water-cooled commercial package air conditioning and heating
equipment (excluding air-cooled, three-phase, small commercial package
air conditioning and heating equipment with a cooling capacity of less
than 65,000 Btu/h).'' 10 CFR 431.92. Additionally, the term in the
current ``basic model'' definition includes ACUACs, ACUHPs, and WCUACs,
but does not explicitly include ECUACs. However, the definition of
``commercial package air-conditioning and heating equipment'' at 10 CFR
431.92 makes clear that that term includes evaporatively-cooled
equipment. Consequently, ECUACs are part of the relevant basic model
definition, so the omission of the term ``evaporatively-cooled'' from
the heading should not impact the proper functioning and use of the
test procedure.
In the August 2023 TP NOPR, DOE proposed to update the definition
of ``basic model'' so that this provision instead applies to the
proposed defined term ``commercial unitary air conditioner and
commercial unitary heat pump,'' which would also inherently include
evaporatively-cooled equipment. 88 FR 56392, 56400 (August 17, 2023).
DOE also proposed editorial changes more generally to the definition of
``basic model'' specified in 10 CFR 431.92 to address that the current
wording could be misinterpreted to read as a definition of each
equipment category, rather than as the definition of what constitutes a
basic model for each equipment category. Id.
DOE did not receive any comments in response to its proposal to
update the definition for ``basic model.'' As discussed in section
III.B.1, DOE is not finalizing the proposed defined term ``commercial
unitary air conditioner and commercial unitary heat pump.'' As such,
DOE is applying the definition of ``basic model'' to the existing
defined term ``commercial package air-conditioning and heating
equipment'' at 10 CFR 431.92. Therefore, other than this terminology
change, DOE is amending the definition for ``basic model'' as proposed,
for the reasons discussed in the preceding paragraphs and in the August
2023 TP NOPR.
3. Double-Duct Definition
DOE established a definition for ``double-duct air conditioner or
heat pump'' at 10 CFR 431.92 (referred to as ``double-duct air
conditioners and heat

[[Page 43995]]

pumps'' or ``double-duct systems'') in an energy conservation standards
direct final rule published in the Federal Register on January 15, 2016
(``January 2016 Direct Final Rule''). 81 FR 2420, 2529. This definition
was included in a term sheet by the ASRAC working group for commercial
package air conditioners (``Commercial Package Air Conditioners Working
Group'') as part of the rulemaking that culminated with the January
2016 Direct Final Rule. (See Document No. 93 in Docket No. EERE-2013-
BT-STD-0007, pp. 4-5) DOE defines ``double-duct systems'' as air-cooled
commercial package air conditioning and heating equipment that: (1) is
either a horizontal single package or split-system unit or a vertical
unit that consists of two components that may be shipped or installed
either connected or split; (2) is intended for indoor installation with
ducting of outdoor air from the building exterior to and from the unit,
as evidenced by the unit and/or all of its components being non-
weatherized, including the absence of any marking (or listing)
indicating compliance with UL 1995,\11\ ``Heating and Cooling
Equipment,'' or any other equivalent requirements for outdoor use; (3)
if it is a horizontal unit, a complete unit has a maximum height of 35
inches; if it is a vertical unit, a complete unit has a maximum depth
of 35 inches; and (4) has a rated cooling capacity greater than or
equal to 65,000 Btu/h and up to 300,000 Btu/h. 10 CFR 431.92.
---------------------------------------------------------------------------

\11\ Underwriters Laboratory (UL) 1995, UL Standard for Safety
for Heating and Cooling Equipment (UL 1995).
---------------------------------------------------------------------------

In the August 2023 TP NOPR, DOE proposed to amend the ``double-duct
air conditioner or heat pump'' definition consistent with the
definition in both AHRI 340/360-2022 and the AHRI 1340-202X Draft. 88
FR 56392, 56400-56401 (August 17, 2023). AHRI 340/360-2022 and the AHRI
1340-202X Draft specify the following definition for ``double-duct
systems'': an air conditioner or heat pump that complies with all of
the following: (1) is either a horizontal single package or split-
system unit; or a vertical unit that consists of two components that
can be shipped or installed either connected or split; or a vertical
single packaged unit that is not intended for exterior mounting on,
adjacent interior to, or through an outside wall; (2) is intended for
indoor installation with ducting of outdoor air from the building
exterior to and from the unit, where the unit and/or all of its
components are non-weatherized; (3) if it is a horizontal unit, the
complete unit shall have a maximum height of 35 in. or the unit shall
have components that do not exceed a maximum height of 35 in. If it is
a vertical unit, the complete (split, connected, or assembled) unit
shall have components that do not exceed maximum depth of 35 in.; (4)
has a rated cooling capacity greater than and equal to 65,000 Btu/h and
less than or equal to 300,000 Btu/h.
In comparison to DOE's definition, DOE noted the following
regarding the definition for double-duct system in AHRI 340/360-2022
and the AHRI 1340-202X Draft: (1) vertical single packaged units not
intended for exterior mounting on, adjacent interior to, or through an
outside wall can be classified as double-duct systems; (2) the maximum
dimensions apply to each component of a split system; and (3) the AHRI
340/360-2022 and AHRI 1340-202X Draft definition does not include
compliance with UL 1995 as a criterion for determining whether a model
is non-weatherized. In the August 2023 TP NOPR, DOE tentatively
concluded that the definition for ``double-duct system'' in section 3.7
of AHRI 340/360-2022 and section 3.12 of the AHRI 1340-202X Draft more
appropriately classifies double-duct systems and differentiates this
equipment from other categories of commercial package air conditioning
and heating equipment. 88 FR 56392, 56400-56401 (August 17, 2023).
DOE did not receive comment regarding the proposed revisions to the
definition for ``double-duct air conditioner or heat pump.'' DOE has
determined that the substance of the definitions for ``double-duct
system'' in AHRI 340/360-2022 and AHRI 1340-2023 better implement the
intent of DOE and the Commercial Package Air Conditioners Working Group
to create a separate equipment class of ACUACs and ACUHPs that are
designed for indoor installation and that require ducting of outdoor
air from the building exterior. 81 FR 2420, 2446 (Jan. 15, 2016). Thus,
DOE is revising the definition of ``double-duct air conditioner or heat
pump'' in 10 CFR 431.92 as proposed in the August 2023 TP NOPR, which
is consistent with the definition in section 3.2.7 of AHRI 1340-2023.
4. Metric Definitions
As mentioned in sections III.D.1 and III.D.2, and discussed in
further detail in section III.E of this final rule, DOE is adopting new
cooling and heating metrics in appendix A1 (i.e., IVEC and IVHE).
Additionally, DOE is adopting three metrics for optional
representations in appendix A1, as discussed further in section III.E.6
of this final rule: energy efficiency ratio 2 (``EER2''), coefficient
of performance 2 (``COP2''), and IVHE for colder climates
(``IVHE<INF>C</INF>''). In the August 2023 TP NOPR, DOE proposed to add
new definitions at 10 CFR 431.92 for the terms ``IVEC,'' ``IVHE,''
``EER2,'' and ``COP2'' that describe what each metric represents, the
test procedure used to determine each metric, and specific designations
applicable to each metric (e.g., IVHE<INF>C</INF>). 88 FR 56392, 56401
(August 17, 2023). DOE did not receive comment on the proposed
definitions for ``IVEC,'' ``IVHE,'' ``EER2,'' and ``COP2.'' Therefore,
DOE is adopting the definitions as proposed in the August 2023 TP NOPR.

C. Updates to Industry Standards

The following sections discuss the changes included in the most
recent updates to AHRI 340/360 and ASHRAE 37, which are incorporated by
reference in the current DOE test procedure for ACUACs and ACUHPs with
a rated cooling capacity greater than or equal to 65,000 Btu/h at 10
CFR 431.96 and 10 CFR part 431, subpart F, appendix A. AHRI 340/360 is
also incorporated by reference in the current DOE test procedure for
ECUACs and WCUACs with a rated cooling capacity greater than or equal
to 65,000 Btu/h at 10 CFR 431.96. The following sections also discuss
the new industry test standard, AHRI 1340-2023, which DOE is
incorporating by reference for use in the new DOE test procedure for
CUACs and CUHPs at 10 CFR part 431, subpart F, appendix A1.
1. AHRI 340/360
As noted previously, DOE's current test procedures for ACUACs,
ACUHPs, and ECUACs and WCUACs with a rated cooling capacity greater
than or equal to 65,000 Btu/h incorporates by reference ANSI/AHRI 340/
360-2007. DOE's current test procedure for ECUACs and WCUACs with a
rated cooling capacity less than 65,000 Btu/h incorporates by reference
ANSI/AHRI 210/240-2008.
The most recent version of ASHRAE Standard 90.1 (i.e., ASHRAE
Standard 90.1-2022) references AHRI 340/360-2022 as the test procedure
for ACUACs, ACUHPs, and ECUACs and WCUACs with a rated cooling capacity
greater than or equal to 65,000 Btu/h. ASHRAE Standard 90.1-2022
included updates to the test procedure references for ECUACs and WCUACs
with capacities less than 65,000 Btu/h to reference AHRI 210/240-2023.
However, ECUACs and WCUACs with capacities less than 65,000 Btu/h are
outside of the scope of AHRI 210/240-2023 and are instead included in
AHRI 340/360-2022. Given

[[Page 43996]]

these changes to the relevant industry test standards, DOE believes
that such reference was an oversight.
The following list includes substantive additions in AHRI 340/360-
2022 as compared to the current Federal test procedures that apply to
CUACs and CUHPs, which reference ANSI/AHRI 340/360-2007 and ANSI/AHRI
210/240-2008:
1. A method for testing double-duct systems at non-zero outdoor air
ESP (see section 6.1.3.7 and appendix I of AHRI 340/360-2022);
2. A method for comparing relative efficiency of indoor integrated
fan and motor combinations (``IFMs'') that allows CUACs and CUHPs with
non-standard (i.e., higher ESP) IFMs to be rated in the same basic
model as otherwise identical models with standard IFMs (see section
D4.2 of appendix D of AHRI 340/360-2022);
3. Requirements for indoor and outdoor air condition measurement
(see appendix C of AHRI 340/360-2022);
4. Detailed provisions for setting indoor airflow and ESP (see
sections 6.1.3.3-6.1.3.5 of AHRI 340/360-2022) and refrigerant charging
instructions to be used in cases in which manufacturer's instructions
conflict or are incomplete (see section 5.8 of AHRI 340/360-2022); and
5. ECUACs and WCUACs with cooling capacities less than 65,000 Btu/h
are included within the scope of the standard.
As discussed, DOE is amending its test procedure for CUACs and
CUHPs by incorporating by reference AHRI 340/360-2022 in appendix A.
Section III.E discusses the specific sections of AHRI 340/360-2022 that
DOE references in the amendments to appendix A adopted in this final
rule. As discussed, DOE is adopting these amendments in accordance with
the requirement 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 AHRI
or ASHRAE, as referenced in ASHRAE Standard 90.1. (42 U.S.C.
6314(a)(4)(A)) As DOE has noted, ASHRAE Standard 90.1 references an
incorrect industry standard for ECUACs and WCUACs with capacities less
than 65,000 Btu/h, AHRI 210/240-2023, so DOE is amending appendix A to
reference the applicable industry standard, AHRI 340/360-2022.
2. AHRI 1340
The recommendations of the ACUAC and ACUHP Working Group TP Term
Sheet have been incorporated into an updated version of AHRI 340/360,
denoted as AHRI 1340-2023, which supersedes AHRI 340/360-2022, but has
not yet been adopted in ASHRAE Standard 90.1. In the August 2023 TP
NOPR, DOE proposed to adopt the AHRI 1340-202X Draft, a draft version
of AHRI 1340 available at the time. DOE noted its intent to update its
incorporation by reference to the final published version of the AHRI
1340-202X Draft, unless there were substantive changes between the
draft and published versions. 88 FR 56392, 56402 (August 17, 2023).
Differences between the ACUAC/ACUHP Working Group TP Term Sheet, the
AHRI 1340-202X Draft, and AHRI 1340-2023 are discussed in the
paragraphs that follow.
The AHRI 1340-202X Draft proposed for adoption in the August 2023
TP NOPR includes recommendations from the ACUAC and ACUHP Working Group
TP Term Sheet described in section III.D of this final rule (including
the IVEC and IVHE metrics). The AHRI 1340-202X Draft also included the
following revisions and additions to the IVEC and IVHE metrics not
included in the ACUAC and ACUHP Working Group TP Term Sheet, which are
discussed in detail in section III.E of this final rule:
1. Detailed test instructions for splitting ESP between the return
and supply ductwork, consistent with ESP requirements recommended in
the ACUAC and ACUHP Working Group TP Term Sheet;
2. Corrections to the hour-based IVEC weighting factors included in
the ACUAC and ACUHP Working Group TP Term Sheet;
3. Correction of the equation in the ACUAC and ACUHP Working Group
TP Term Sheet for calculating adjusted ESP for any cooling or heating
tests conducted with an airflow rate that differs from the full-load
cooling airflow;
4. Addition of separate hour-based weighting factors and bin
temperatures to calculate a separate version of IVHE that is
representative of colder climates, designated IVHEC;
5. Changes to the default fan power and maximum pressure drop used
for testing coil-only systems;
6. Additional instruction for component power measurement during
testing;
7. Corrections to equations used for calculating IVHE;
8. Provisions for testing with non-standard low-static indoor fan
motors; and
9. Revision to the power adder for WCUACs that reflects power that
would be consumed by field-installed heat rejection components.
Since publication of the August 2023 TP NOPR, the AHRI 1340-202X
Draft was finalized and published as AHRI 1340-2023 in December 2023.
DOE has reviewed AHRI 1340-2023 and has identified that AHRI 1340-2023
includes the previously discussed revisions and additions to the IVEC
and IVHE metrics in the AHRI 1340-202X Draft that were not included in
the ACUAC and ACUHP Working Group TP Term Sheet. AHRI 1340-2023 also
includes several revisions and updates to the test procedures specified
in the AHRI 1340-202X Draft. DOE reviewed these revisions and updates,
which include the following items, and discusses them in detail in
sections III.E.3, III.E.7, III.E.8, III.F, and III.H of this document.
Those sections also include discussion of the justification for
adopting the content of these changes (which are largely consistent
with corresponding proposals in the August 2023 TP NOPR) in this final
rule.
1. A method for calculating capacity and fan power adjustments for
coil-only systems operating at part-load airflow, consistent with DOE's
proposal in the August 2023 TP NOPR;
2. Addition of a method to verify cut-in and cut-out temperatures,
consistent with DOE's proposal in the August 2023 TP NOPR but with
additional specificity;
3. Addition of an optional boost 2 test for optional
representations of 5 [deg]F capacity and performance for systems with
more than two operating levels;
4. Allowance for the test conducted at 5 [deg]F and 17 [deg]F at
the boost heating operating level to be used for IVHE bins ranging from
5 [deg]F to 21 [deg]F;
5. Revisions to appendix D of AHRI 1340 to align with the specific
components approach proposed by DOE in the August 2023 TP NOPR, and
inclusion of provision for how to test models with drain pan heaters
present; and
6. Revisions to the test temperatures for ECUACs and WCUACs and
corresponding revision to the tower fan and pump power values for
WCUACs.
Consistent with the proposals in the August 2023 TP NOPR, in this
final rule DOE is incorporating by reference AHRI 1340-2023 in the new
test procedure at appendix A1 as DOE has determined, supported by clear
and convincing evidence, that AHRI 340/360-2022 cannot provide
representative energy use results for the IVEC and IVHE efficiency
metrics. Further, DOE has determined that AHRI 1340-2023 would not be
unduly burdensome to conduct and reflects energy efficiency during a
representative average use cycle for the

[[Page 43997]]

IVEC and IVHE efficiency metrics. Specific aspects of AHRI 1340-2023
are discussed in more detail in section III.E. Section III.E of this
document also discusses comments received on DOE's proposal to adopt
the AHRI 1340-202X Draft, as well as the specific sections of AHRI
1340-2023 that DOE references in appendix A1.
3. ASHRAE 37
ANSI/ASHRAE 37-2009, which provides a method of test for many
categories of air conditioning and heating equipment, is referenced for
testing CUACs and CUHPs by AHRI 340/360-2022 and AHRI 1340-2023. More
specifically, sections 5 and 6 and appendices C, D, and E of AHRI 340/
360-2022 and sections 5 and 6 and appendices C, D, and E of AHRI 1340-
2023 reference methods of test in ANSI/ASHRAE 37-2009. DOE currently
incorporates by reference ANSI/ASHRAE 37-2009 in 10 CFR 431.95, and the
current incorporation by reference applies to the current Federal test
procedure for ACUACs and ACUHPs specified at appendix A. The current
Federal test procedures at 10 CFR 431.96 for ECUACs and WCUACs do not
explicitly reference ANSI/ASHRAE 37-2009. In the August 2023 TP NOPR,
DOE proposed to maintain the incorporation by reference of ANSI/ASHRAE
37-2009 to the proposed appendix A, which would also apply ANSI/ASHRAE
37-2009 to testing ECUACs and WCUACs, and to incorporate by reference
ANSI/ASHRAE 37-2009 for use with appendix A1. 88 FR 56392, 56402
(August 17, 2023). DOE did not receive any comments regarding its
proposal to incorporate by reference ANSI/ASHRAE 37-2009 to both
appendices A and A1. Therefore, as proposed, DOE is maintaining its
incorporation by reference of ANSI/ASHRAE 37-2009 in appendix A and
incorporating by reference ANSI/ASHRAE 37-2009 in appendix A1. Section
III.E of this document discusses the specific sections of ANSI/ASHRAE
37-2009 that DOE references in appendices A and A1.

D. Term Sheet Recommendations and Metrics

As previously mentioned, DOE published in the Federal Register the
July 2022 Notice of Intent. 87 FR 45703 (July 29, 2022). DOE then
established the Working Group in accordance with FACA and NRA. The
Working Group consisted of 14 members and met six times, while the
Working Group's subcommittee met an additional seven times. The Working
Group meetings were held between September 20, 2022, and December 15,
2022, after which the Working Group successfully reached consensus on
an amended test procedure. The Working Group signed a term sheet of
recommendations on December 15, 2022. (See EERE-2022-BT-STD-0015-0065)
The Working Group addressed the following aspects of the test procedure
for ACUACs and ACUHPs:
1. Mathematical representation of cooling efficiency: The current
cooling metric specified by AHRI 340/360-2022 (i.e., IEER) represents a
weighted average of the measured energy efficiency ratios (EER)
measured at four distinct test conditions, whereas the IVEC metric is
calculated as the total annual cooling capacity divided by the total
annual energy use, as discussed further in section III.D.1 of this
document. The Working Group agreed that this calculation approach
provides a more mathematically accurate way of representing the cooling
efficiency of ACUACs and ACUHPs compared to the current approach used
for IEER. As part of this equation format, the IVEC metric also uses
hour-based weighting factors to represent the time spent per year in
each operating mode.
2. Integrated heating metric: The current heating metric for ACUHPs
(i.e., COP) represents the ratio of heating capacity to the power
input, calculated at a single test condition of 47 [deg]F. COP does not
account for the performance at part-load or over the range of
temperatures seen during an average heating season, and it does not
include energy use in heating season ventilation mode. IVHE accounts
for both full-load and part-load operation at a range of typical
ambient temperatures seen during the heating season, and it includes
energy use in heating season ventilation mode. Analogous to IVEC, the
IVHE metric is calculated as the total annual heating load divided by
the total annual energy use, as discussed further in section III.D.2 of
this document, and the metric also uses hour-based weighting factors to
represent the time spent per year in each operating mode.
3. Operating modes other than mechanical cooling: The IEER metric
currently does not include the energy use of operating modes other than
mechanical cooling, such as economizer-only cooling and cooling season
ventilation. The newly established IVEC metric includes the energy use
of these other modes.
4. ESP: The IVEC and IVHE metrics require increased ESPs--in
comparison to the ESPs required for determining IEER and COP--to more
accurately represent ESPs and corresponding indoor fan power that would
be experienced in real-world installations.
5. Crankcase heater operation: The current IEER metric includes
crankcase heater power consumption only when operating at part-load
compressor stages (i.e., for part-load cooling operation, crankcase
heater power is included only for higher-stage compressors that are
staged off, and it is not included for lower-stage compressors when all
compressors are cycled off). The COP metric does not include any
crankcase heater power consumption. In contrast, the IVEC and IVHE
metrics include all annual crankcase heater operation, including when
all compressors are cycled off in part-load cooling or heating,
ventilation mode, unoccupied no-load hours, and in heating season (for
ACUACs only).
6. Oversizing: The current IEER and COP metrics do not consider
that ACUACs and ACUHPs are typically oversized in field installations.
In contrast, the IVEC and IVHE metrics include an oversizing factor of
15 percent (i.e., it is assumed that the unit's measured full-load
cooling capacity is 15 percent higher than the peak building cooling
load and peak building heating load). Accounting for oversizing is more
representative of the load fractions seen in field applications and
better enables the test procedure to differentiate efficiency
improvements from the use of modulating/staged components.
Based on discussions related to these six topics, the Working Group
developed the ACUAC and ACUHP Working Group TP Term Sheet, which
includes the following recommendations:
1. A recommendation to adopt the latest version of AHRI 340/360-
2022 with IEER and COP metrics required for compliance beginning 360
days from the date a test procedure final rule publishes (see
Recommendation #0);
2. The IVEC efficiency metric, to be required on the date of
amended energy conservation standards for ACUACs and ACUHPs (see
Recommendation #1);
3. Hour-based weighting factors for the IVEC metric (see
Recommendation #2);
4. Details on determination of IVEC, including provisions for
determining IVEC in appendix B of the ACUAC and ACUHP Working Group TP
Term Sheet (see Recommendation #3);
5. Target load fractions and temperature test conditions for IVEC,
which account for oversizing (see Recommendation #4);
6. A requirement that representations of full-load EER be made in
accordance

[[Page 43998]]

with the full-load ``A'' test (see Recommendation #5); \12\
---------------------------------------------------------------------------

\12\ Similar to the current test procedure for determining IEER,
the test procedure recommended in the ACUAC and ACUHP Working Group
TP Term Sheet includes four cooling tests designated with letters
``A,'' ``B,'' ``C,'' and ``D.'' The ``A'' test is a full-load
cooling test, while the ``B,'' ``C,'' and ``D'' tests are part-load
cooling tests.
---------------------------------------------------------------------------

7. A requirement to provide representations of airflow used for the
full-load ``A'' test and the part-load ``D'' test (i.e., the airflow
used in the lowest-stage test for the D point), and a provision for
determining the minimum airflow that can be used for testing (see
Recommendation #6);
8. The IVHE efficiency metric (see Recommendation #7);
9. Hour-based weighting factors, load bins, and outdoor air
temperatures for each bin (i.e., temperatures used for the building
heating load line, not test temperature conditions) for the IVHE metric
(see Recommendation #8);
10. The test conditions and list of required and optional tests and
representations for the IVHE metric (see Recommendation #9);
11. Provisions for manufacturers to certify cut-in and cut-out
temperatures for heat pumps to DOE and provisions for a DOE
verification test of those temperatures (see Recommendation #10);
12. Commitment of the Working Group to analyze ventilation and fan-
only operation included in the IVEC and IVHE metrics to validate that
these metrics adequately capture fan energy use during the energy
conservation standards portion of the negotiated rulemaking. If the
IVEC and IVHE levels do not adequately drive more efficient air moving
systems that are technologically feasible and economically justified,
the Working Group committed to developing a metric addressing furnace
fan energy use (see Recommendation #11);
13. ESP requirements for the IVEC and IVHE metrics, requirements
for splitting the ESP requirements between the return and supply ducts,
and a requirement that certified airflow for full load and D bin be
made public in the DOE Compliance Certification Database (see
Recommendation #12);
14. Provisions requiring manufacturers to certify crankcase heater
wattages and tolerances for certification (see Recommendation #13); and
15. Provisions that the contents of the ACUAC and ACUHP Working
Group TP Term Sheet be implemented in a test procedure NOPR and final
rule, with the final rule issuing no later than any energy conservation
standards direct final rule (see Recommendation #14).
The following sections provide a summary of the development and
final recommendations regarding the IVEC and IVHE cooling and heating
metrics in the ACUAC and ACUHP Working Group TP Term Sheet.
1. IVEC
For the new cooling metric, the Working Group determined to
prospectively modify the climate zones and building types accounted for
in the test procedure as compared to those included in the existing DOE
test procedure, in order to improve the representativeness of the
metrics to better reflect the broad range of applications of CUACs and
CUHPs. To do so, the Working Group utilized hour-based weighting
factors, which represent the average time spent per year in each
operating mode and load bin. To develop these weighting factors,
members of the Working Group used building modeling developed by
Carrier that was based on 10 ASHRAE Standard 90.1 building prototypes
across all U.S. climate zones. (See EERE-2022-BT-STD-0015-0019) The
resulting hour-based weighting factors are provided in Recommendation
#2 of the ACUAC and ACUHP Working Group TP Term Sheet. (See EERE-2022-
BT-STD-0015-0065)
The ACUAC and ACUHP Working Group concluded that including
economizer-only cooling and cooling season ventilation operating modes
in a seasonal cooling metric would improve the representativeness for
ACUACs and ACUHPs, and as such, included these modes in the IVEC metric
outlined in Recommendation #1 and the hour-based weighting factors in
Recommendation #2 of the ACUAC and ACUHP Working Group TP Term Sheet.
Appendix B of the ACUAC and ACUHP Working Group TP Term Sheet provides
the recommended calculation method for the IVEC method and includes
sections specifying the methods for including ventilation and
economizer-only cooling operation in the calculation of IVEC. (See
EERE-2022-BT-STD-0015-0065)
The Working Group also considered ESP requirements for the IVEC and
IVHE metrics. Stakeholders indicated the need for higher ESP
requirements to improve representativeness of field performance.
Additionally, stakeholders discussed the importance of maintaining
uniformity in testing of units at higher ESP conditions. (See EERE-
2022-BT-STD-0015-0062 at p. 11) The ESP requirements agreed to by the
Working Group are provided in Recommendation #12 of the ACUAC and ACUHP
Working Group TP Term Sheet (see EERE-2022-BT-STD-0015-0065) and
include the following:
1. Higher ESP requirements for testing: As discussed previously,
the minimum ESP conditions recommended by the Working Group are
provided in Table III-1.
[GRAPHIC] [TIFF OMITTED] TR20MY24.128

2. Economizer pressure drop: ASHRAE Standard 90.1-2022 requires the
use of economizers for comfort cooling applications for almost all U.S.
climate zones. The analysis conducted by Carrier in support of the
Working Group indicates that over 96 percent of buildings require the
use of economizers. (see EERE-2022-BT-STD-0015-0019 at p. 14)
Economizers installed in CUACs and CUHPs add internal static pressure
that the indoor

[[Page 43999]]

fan has to overcome, even when the economizer dampers are closed. The
current DOE test procedure does not require the installation of an
economizer on a tested unit, and DOE is aware that manufacturers
generally do not test CUACs and CUHPs with economizers installed. The
ESP requirements specified by the current DOE test procedure are the
same regardless of whether a unit is tested with or without an
economizer. As such, testing a unit without an economizer does not
reflect the total static pressure that would be experienced in the
field for installations that require the use of an economizer.
Accordingly, in order to better represent the fan power of ACUACs and
ACUHPs that are typically installed with economizers, the Working Group
recommended that for all units tested without an economizer installed,
0.10 in. H2O shall be added to the full-load ESP values specified in
Table III-1.\13\
---------------------------------------------------------------------------

\13\ An economizer is an apparatus that supplies outdoor air to
reduce or eliminate the need for mechanical cooling during mild or
cooler weather.
---------------------------------------------------------------------------

3. Return and supply static split requirements: Test procedures for
CUACs and CUHPs include ESP requirements that reflect the total ESP
applied within the return and supply ductwork of the test set-up. The
current Federal test procedure does not specify requirements for how
ESP is distributed during testing (i.e., the relative contribution from
return ductwork versus supply ductwork). Given the recommendation to
increase the required ESP levels for testing, the Working Group
concluded that the higher ESP conditions could cause variability in
test results if the distribution of ESP between return ductwork and
supply ductwork were not specified in the revised test procedure.
Therefore, to ensure repeatable and reproducible testing conditions for
CUAC and CUHP units, the Working Group recommended specifying that ESP
requirements be split with 25 percent applied in the return ductwork
and the remaining 75 percent applied in the supply ductwork. The
Working Group further recommended that the fraction of ESP applied in
the return ductwork shall have a -5/+0 percent tolerance (i.e., the
return static must be within 20 to 25 percent of the total ESP) for the
full-load cooling test. In a case where there is no additional
restriction on the return duct and more than 25 percent of the ESP is
already applied in the return ductwork without a restriction, then
greater than 25 percent ESP in the return ductwork will be allowed.
Once set for the full-load cooling test, these restriction settings
shall remain unchanged for the other cooling and heating tests
conducted.
To incorporate the various changes involved in testing requirements
and weighting factors already discussed, the Working Group created the
IVEC metric provided in Recommendation #1 with further specifications
in appendix B of the ACUAC and ACUHP Working Group TP Term Sheet. The
IVEC metric is a summation formula analogous to the seasonal energy
efficiency ratio 2 (``SEER2'') metric designated for residential
central air conditioner and central air conditioning heat pumps (``CAC/
HP'') equipment. (See appendix M1 to subpart B of 10 CFR part 430,
``Uniform Test Method for Measuring the Energy Consumption of Central
Air Conditioners and Heat Pumps.'') Stated simply, the IVEC metric is
calculated by dividing the total annual cooling capacity by the total
annual energy use. Key aspects encompassed in the IVEC metric include
the following:
1. Accounting for energy consumed in different modes: The IVEC
metric includes energy use during mechanical cooling, integrated
mechanical and economizer cooling, economizer-only cooling, cooling
season ventilation, unoccupied no-load hours, and heating season
operation of crankcase heat (for CUACs only). Appendix B of the ACUAC
and ACUHP Working Group TP Term Sheet specifies instructions for
determining energy consumption during each mode.
2. Testing parameters: The ACUAC and ACUHP Working Group TP Term
Sheet further specifies instructions in appendix B for the mechanical
cooling tests at each target mechanical load. These methodologies and
tolerances mirror those specified in AHRI 340/360-2022, including a 3-
percent tolerance on the target mechanical load for part-load tests,
and in cases when the target mechanical load cannot be met within
tolerance, instructions for using interpolation and cyclic degradation
to determine the performance at the target test point.
3. Target load percentages: Recommendation #4 of the ACUAC and
ACUHP Working Group TP Term Sheet includes target conditions for
testing, including load percentages for testing units at part-load
conditions. For each bin, the specified target load percent (%Loadi)
reflects the average load as a percentage of the full-load capacity for
that bin met by using all modes of cooling, and is used for determining
total annual cooling provided in the numerator of the IVEC equation.
The target mechanical load percent (%Loadi,mech) is the average load
for each bin met only through mechanical cooling (i.e., mechanical-only
cooling and the mechanical portion of integrated mechanical and
economizer cooling) and is the target load fraction used for the part-
load cooling test for each bin.
As mentioned, the IVEC metric includes the annual operation of
crankcase heaters for CUACs and CUHPs. Appendix B of the ACUAC and
ACUHP Working Group TP Term Sheet further specifies the accounting of
crankcase heater energy consumption in each operating mode.
Recommendation #2 of the ACUAC and ACUHP Working Group TP Term Sheet
specifies hour-based weighting factors to account for crankcase heat
operation in unoccupied no-load cooling season hours for CUACs and
CUHPs, as well as heating season hours for CUACs. Appendix B of the
ACUAC and ACUHP Working Group TP Term Sheet also specifies that for
part-load cooling tests, crankcase heat is accounted for in power
measurements of higher-stage compressors that are staged off during
testing, while crankcase heat operation of lower-stage compressors when
cycled off as well as crankcase heat operation in other operating modes
is calculated using the certified crankcase heater power.
The IVEC metric also accounts for a 15-percent oversizing factor.
Accordingly, the target load percentages specified in Recommendation #4
include this 15-percent oversizing factor. Additionally, the A test
condition is excluded from the IVEC calculation; however, the A test is
still a required test point for determining full-load capacity.
IVEC includes outdoor and return air dry-bulb and wet-bulb test
temperatures that differ from those used in the current test procedure
for determining IEER, as shown in Table III-2.

[[Page 44000]]

[GRAPHIC] [TIFF OMITTED] TR20MY24.129

The IVEC metric also limits the minimum airflow that can be used
for testing. This minimum airflow limit calculation method is based on
the average ventilation rate determined in building modeling performed
to develop IVEC and is a function of the full-load cooling capacity.
Unlike AHRI 340/360-2022 (see section 6.1.3.4.5), the provisions for
determining IVEC do not specify separate test provisions for setting
airflow during part-load tests of multi-zone variable air volume
(``MZVAV'') units. Rather, the part-load airflow used for testing all
CUACs and CUHPs will be based on the certified part-load cooling
airflow.
2. IVHE
The IVHE metric specified in the ACUAC and ACUHP Working Group TP
Term Sheet differs from the COP heating efficiency metric specified in
the current DOE test procedure by the inclusion of heating season
operating modes not currently accounted for, a combined seasonal
performance metric rather than individual ratings at specific
temperature conditions, and additional optional test conditions. In
alignment with the development of the IVEC metric described in section
III.D.1 of this final rule, the Working Group determined to utilize
hour-based weighting factors to account for heating loads across more
building types and climate zones than are included in the current DOE
test procedure. The building heating load lines and hours developed for
the IVHE metric rely on a similar ASHRAE Standard 90.1 building and
climate zone analysis as the one conducted for the IVEC metric
development. Additionally, in developing the heating load line on which
the hour-based weighting factors rely, the Working Group utilized the
previously discussed 15-percent oversizing factor and assumed a heat-
to-cool ratio of 1, as outlined in Recommendation #8 (i.e., assumed the
peak building cooling load equals the peak building heating load).
The heating rating requirements recommended in the ACUAC and ACUHP
Working Group TP Term Sheet include several distinct provisions
regarding testing requirements from the existing DOE test procedure. In
the current DOE test procedure, CUHPs are required to be tested only at
a 47 [deg]F full-load condition to generate a COP rating.
Recommendation #9 of the ACUAC and ACUHP Working Group TP Term Sheet,
however, introduces several provisions with significant differences
from the existing DOE test procedure. First, the recommendation
includes required testing at 47 [deg]F and 17 [deg]F full-load
conditions, aligning with those previously specified in AHRI 340/360-
2022. Additionally, the recommendation introduces optional part-load
test conditions at both 47 [deg]F and 17 [deg]F temperature conditions,
as well as test conditions for optional testing at a 5 [deg]F full-load
condition. Finally, the recommendation includes test requirements for
optional boost tests at the 17 [deg]F and 5 [deg]F test conditions for
variable-speed units. Additionally, the IVHE metric incorporates two
operating modes previously excluded from the DOE test procedure:
heating season ventilation mode and supplemental electric resistance
heat operation. Lastly, the IVHE test conditions rely on the same ESP
requirements per capacity bin as those specified for IVEC, as detailed
in Recommendation #12. The airflow provisions pertaining to IVEC
mentioned in section III.D.1 of this final rule (i.e., a limit on
minimum airflow used for testing and no separate test provisions for
MZVAV units) apply to the test provisions for the IVHE metric as well.
The results from optional and required testing, as well as the
newly included operating modes, are included in the calculation of the
IVHE metric utilizing the weighting factors outlined in Recommendation
#8 and calculation methods from appendix C of the ACUAC and ACUHP
Working Group TP Term Sheet. The calculation methods for IVHE that
implement these changes are further detailed in the paragraphs that
follow.
The IVHE metric includes contributions from both mechanical and
resistance heating to meet building heating load. Similar to the IVEC
calculation approach, the IVHE metric is calculated by dividing the
total annual building heating load by the total annual energy use.
Recommendations #8, #9, and #10, as well as appendices B and C of
the ACUAC and ACUHP Working Group TP Term Sheet, provide the
calculation methods for the IVHE metric. The hour-based weighting
factors and bin temperatures for IVHE are included in Recommendation #8
of the ACUAC and ACUHP Working Group TP Term Sheet, which specifies 10
distinct load-based bins alongside weighting factors for heating season
ventilation and operation of crankcase heat in unoccupied no-load
heating season hours. The calculation methods outlined for the IVHE
metric in the ACUAC and ACUHP Working Group TP Term Sheet are specified
as the following:
1. Building load calculation: Recommendation #8 includes the
calculation method for the building load in each load bin based on the
measured full-load cooling capacity.
2. Interpolation between temperatures: Appendix C of the ACUAC and
ACUHP Working Group TP Term Sheet specifies interpolation instructions
for the various test temperatures specified in Recommendation #8.
Interpolation instructions are specified for bins with temperatures
between 17 [deg]F and 47 [deg]F. Appendix C also includes the following
instructions for bins with temperatures less than 17 [deg]F: (1)
interpolation instructions to be used if the optional

[[Page 44001]]

5 [deg]F test is conducted, and (2) extrapolation instructions
utilizing the 47 [deg]F and 17 [deg]F test data to be used if the 5
[deg]F test is not conducted.
3. Determination of heating stage, auxiliary heat, and cyclic
degradation: For load bins in which the calculated building load
exceeds the highest-stage mechanical heating capacity determined for
the bin temperature, appendix C of the ACUAC and ACUHP Working Group TP
Term Sheet includes calculation methods for determining the power
required by auxiliary resistance heat and is included in the overall
IVHE calculation. For load bins in which the calculated building load
is lower than the lowest-stage mechanical heating capacity determined
for the bin temperature, appendix C of the ACUAC and ACUHP Working
Group TP Term Sheet includes calculation methodology for calculating
power and incorporating cyclic degradation with a cyclic degradation
factor of 0.25. This cyclic degradation methodology is consistent with
the methodology specified in appendix M1 to subpart B of 10 CFR part
430 for residential central heat pumps. For load bins in which the
calculated building load is in between the lowest-stage and highest-
stage mechanical heating capacities determined for the bin temperature,
appendix C of the ACUAC and ACUHP Working Group TP Term Sheet includes
calculations for determining power based on interpolation between
performance of mechanical heating stages.
4. Defrost degradation: The capacity calculations for all load bins
with temperatures less than 40 [deg]F include a defrost degradation
coefficient, with calculations specified in appendix C of the ACUAC and
ACUHP Working Group TP Term Sheet.
5. Cut-out factor: Recommendation #10 of the ACUAC and ACUHP
Working Group TP Term Sheet specifies that manufacturers will certify
cut-in and cut-out temperatures, or the lack thereof, to DOE to ensure
resistance-only operation is included at temperatures below which
mechanical heating would not operate. This restriction is implemented
in calculations through a cut-out factor included in appendix C. DOE is
not amending the certification or reporting requirements for ACUHPs in
this final rule to require reporting cut-in and cut-out temperatures.
Instead, DOE may consider proposals to amend the certification and
reporting requirements for this equipment under a separate rulemaking
regarding appliance and equipment certification.
6. Crankcase heater power contribution: In alignment with the
inclusion of crankcase heater power contribution in IVEC, appendix C of
the ACUAC and ACUHP Working Group TP Term Sheet specifies a method for
incorporating crankcase heat power for all heating season operating
modes for ACUHPs. Specifically, for part-load heating tests, crankcase
heat is accounted for in power measurements of higher-stage compressors
that are staged off during testing, while crankcase heat operation of
lower-stage compressors when cycled off, as well as crankcase heat
operation in other operating modes, is calculated using the certified
crankcase heater power.

E. DOE Adopted Test Procedures and Comments Received

In the August 2023 TP NOPR, DOE proposed to maintain the current
efficiency metrics of IEER, EER, and COP in appendix A, and reference
AHRI 340/360-2022 in appendix A for measuring the existing metrics. 88
FR 56392, 56403-56404 (August 17, 2023). Additionally, DOE proposed to
establish a new test procedure at appendix A1 that adopts the substance
of the AHRI 1340-202X Draft, including the new IVEC and IVHE metrics,
through incorporation by reference of a finalized version of that
industry test standard. Id. The following sections discuss DOE's
proposals, comments received, and DOE's adopted provisions regarding
(1) AHRI 1340-2023 and the IVEC and IVHE metrics; (2) double-duct
systems; (3) ECUACs and WCUACs; (4) the IVHE metric for colder
climates; (5) the test conditions used in appendix A; (6) the test
conditions used in appendix A1; (7) provisions introduced in the AHRI
1340-202X Draft that are not included in the ACUAC and ACUHP Working
Group TP Term Sheet; and (8) heating test provisions introduced in AHRI
1340-2023.
1. Overall
As discussed, DOE proposed to establish a new test procedure at
appendix A1 that would adopt the AHRI 1340-202X Draft, including the
newly proposed IVEC and IVHE metrics. DOE noted its intent to ideally
incorporate by reference a finalized version of that industry test
standard. DOE further stated that if a finalized version of the AHRI
1340-202X Draft is not published before the test procedure final rule,
or if there are substantive changes between the draft and published
versions of the standard that are not supported by stakeholder comments
in response to this NOPR, DOE may adopt the substance of the AHRI 1340-
202X Draft or provide additional opportunity for comment on the final
version of that industry consensus standard. Id. As noted in the August
2023 TP NOPR, certain provisions in the current appendix A and table 1
to 10 CFR 431.96(b) (e.g., regarding minimum ESP, optional break-in)
would be redundant with the reference to AHRI 340/360-2022, and, as
such, DOE proposed to remove those explicit provisions from table 1 to
10 CFR 431.96(b) and appendix A, and instead reference them through the
relevant provisions of the updated AHRI 340/360. Id.
Further, in both appendix A and appendix A1, DOE proposed to
incorporate by reference ANSI/ASHRAE 37-2009. Id.
Specifically for appendix A1, DOE proposed to adopt certain
sections of the AHRI 1340-202X Draft to determine IVEC and IVHE, which
are generally consistent with the recommendations from the ACUAC and
ACUHP Working Group TP Term Sheet. Id. The ACUAC and ACUHP Working
Group TP Term Sheet applies only to the test procedures for ACUACs and
ACUHPs, excluding double-duct systems. However, the AHRI 1340-202X
Draft proposed for adoption in the August 2023 TP NOPR, as well as the
final version of the standard (i.e., AHRI 1340-2023), include
additional provisions for determining IVEC and IVHE for double-duct
systems, ECUACs, and WCUACs, indicating industry consensus that these
metrics are appropriate for these categories of CUACs and CUHPs. Id.
DOE requested comment on the proposed adoption of the IVEC and IVHE
metrics as determined using the AHRI 1340-202X Draft in appendix A1 for
all CUACs and CUHPs. Id.
On this topic, AHRI, ASAP & ACEEE, Carrier, the CA IOUs, Lennox,
NEEA, Rheem, and Trane generally supported the proposal to adopt the
IVEC and IVHE metrics as determined in the AHRI 1340-202X Draft,
consistent with the ACUAC and ACUHP Working Group TP Term Sheet. (AHRI,
No. 15 at pp. 1, 5; ASAP & ACEEE, No. 11 at p. 1; Carrier, No. 8 at p.
2; CA IOUs, No. 10 at pp. 1-2; Lennox, No. 9 at p. 2; NEEA, No. 16 at
pp. 1-2; Rheem, No. 12 at p. 2, Trane, No. 14 at p. 1) NEEA
specifically supported the ESP requirements proposed by DOE consistent
with the recommendations of the ACUAC and ACUHP Working Group TP Term
Sheet. (NEEA, No. 16 at p. 2) The CA IOUs stated that the new test
procedure improves representativeness. (CA IOUs, No. 10 at p. 1) AHRI
and ASAP & ACEEE acknowledged the efforts made by the AHRI Commercial
Unitary Standards Technical Committee

[[Page 44002]]

(``STC'') and supported the corrections and additions to the ACUAC and
ACUHP Working Group TP Term Sheet included in the AHRI 1340-202X Draft.
(AHRI, No. 15 at pp. 1-2; ASAP & ACEEE, No. 11 at p. 1)
As proposed, DOE is adopting the most recent version of AHRI
Standard 340/360 (i.e., AHRI 340/360-2022) in appendix A for testing
CUACs and CUHPs (including ACUACs, ACUHPs, ECUACs, WCUACs, and double-
duct systems) to measure the current metrics--EER, IEER, and COP.
Specifically, DOE is adopting the following sections of AHRI 340/360-
2022: sections 3 (with certain exclusions \14\), 4, 5, and 6, and
appendices A, C, D (excluding sections D1 through D3), and E. As
proposed, DOE is also removing certain provisions from table 1 to 10
CFR 431.96(b) and the current appendix A that are redundant with the
reference to AHRI 340/360-2022 adopted in appendix A in this final
rule. As discussed, DOE is adopting these amendments in accordance with
the requirement 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 AHRI
or ASHRAE, as referenced in ASHRAE Standard 90.1. (42 U.S.C.
6314(a)(4)(A))
---------------------------------------------------------------------------

\14\ DOE is not referencing the following provisions in section
3 of AHRI 340/360-2022 because the terms are either defined at 10
CFR 431.92 or are not needed for the DOE test procedure: 3.2 (Basic
Model), 3.4 (Commercial and Industrial Unitary Air-conditioning
Equipment), 3.5 (Commercial and Industrial Unitary Heat Pump), 3.7
(Double-duct System), 3.8 (Energy Efficiency Ratio), 3.12 (Heating
Coefficient of Performance), 3.14 (Integrated Energy Efficiency
Ratio), 3.23 (Published Rating), 3.26 (Single Package Air-
Conditioners), 3.27 (Single Package Heat Pumps), 3.29 (Split System
Air-conditioners), 3.30 (Split System Heat Pump), and 3.36 (Year
Round Single Package Air-conditioners).
---------------------------------------------------------------------------

As discussed in section III.C.2 of this document, AHRI 1340-2023
includes certain updates that are not included in the ACUAC and ACUHP
Working Group TP Term Sheet. Most of these updates were included in the
AHRI 1340-202X Draft, and they are discussed in detail in section
III.E.7 of this final rule. There are also several updates included
AHRI 1340-2023 that were not included in the AHRI 1340-202X Draft,
notably regarding ECUACs and WCUACs (discussed in further detail in
section III.E.3 of this document) and boost heating tests (described in
further detail in section III.E.8 of this document). Based on comments
received and DOE's review of AHRI 1340-2023, DOE has determined that
the updates to the test procedure in AHRI 1340-2023 are appropriate,
consistent with the intent of the ACUAC and ACUHP Working Group TP Term
Sheet and the intent of the provisions proposed in the August 2023 TP
NOPR, and improve the representativeness of the test procedure.
DOE has determined that the recommendations specified in the ACUAC
and ACUHP Working Group TP Term Sheet are consistent with the EPCA
requirement that test procedures for covered equipment, including CUACs
and CUHPs, be reasonably designed to produce test results that reflect
energy efficiency, energy use, and estimated operating costs of a type
of industrial equipment (or class thereof) during a representative
average use cycle (as determined by the Secretary), and shall not be
unduly burdensome to conduct (42 U.S.C. 6314(a)(2)). As a result, DOE
is adopting a new test procedure in appendix A1 in accordance with the
Term Sheet. Therefore, DOE is amending the test procedure for CUACs and
CUHPs to adopt in the new appendix A1 the test provisions in AHRI 1340-
2023 and ASHRAE 37-2009. DOE is adopting the following sections of AHRI
1340-2023 in appendix A1: sections 3 (with certain exclusions),\15\ 4,
5 (excluding section 5.2), and 6.1 through 6.3, and appendices A, C, D
(excluding sections D.1 and D.2), and E. Use of appendix A1 will not be
required until the compliance date of amended energy conservation
standards denominated in terms of the new metrics in appendix A1,
should such standards be adopted.
---------------------------------------------------------------------------

\15\ DOE is not referencing the following provisions in section
3 of AHRI 1340-2023 because the terms are either defined at 10 CFR
431.92 or are not needed for the DOE test procedure: 3.2.2
(Barometric Relief Dampers), 3.2.3 (Basic Model), 3.2.5 (Commercial
and Industrial Unitary Air-conditioning Equipment), 3.2.5.1
(Commercial and Industrial Unitary Air-Conditioning System), 3.2.5.2
(Commercial and Industrial Unitary Heat Pump), 3.2.7 (Double-duct
System), 3.2.9 (Desiccant Dehumidification Component), 3.2.10 (Drain
Pan Heater), 3.2.11.1 (Air Economizer), 3.2.12 (Energy Efficiency
Ratio 2), 3.2.13 (Evaporative Cooling), 3.2.13.1 (Direct Evaporative
Cooling System), 3.2.13.2 (Indirect Evaporative Cooling System),
3.2.14 (Fresh Air Damper), 3.2.15 (Fire, Smoke, or Isolation
Damper), 3.2.17 (Hail Guard), 3.2.19 (Heating Coefficient of
Performance 2), 3.2.20 (High-Effectiveness Indoor Air Filtration),
3.2.22 (Indoor Single Package Air-conditioners), 3.2.23 (Integrated
Ventilation, Economizing, and Cooling Efficiency (IVEC)), 3.2.34
(Integrated Ventilation and Heating Efficiency (IVHE)), 3.2.29 (Non-
standard Ducted Condenser Fan), 3.2.31.2 (Boost2 Heating Operational
Level (B2)), 3.2.34 (Power Correction Capacitor), 3.2.35 (Powered
Exhaust Air Fan), 3.2.36 (Powered Return Air Fan), 3.2.37 (Process
Heat Recovery, Reclaim, or Thermal Storage Coil), 3.2.38 (Published
Rating), 3.2.41 (Refrigerant Reheat Coil), 3.2.42 (Single Package
Air-Conditioners), 3.2.43 (Single Package Heat Pumps), 3.2.45 (Sound
Trap), 3.2.46 (Split System), 3.2.51 (Steam or Hydronic Heat Coils),
3.2.53 (UV Lights), 3.2.55 (Ventilation Energy Recovery System
(VERS)), 3.2.56 (Year Round Single Package Air-conditioners), and
3.2.57 (Year Round Single Package Heat Pump).
---------------------------------------------------------------------------

As proposed, for appendices A and A1, DOE is incorporating by
reference ANSI/ASHRAE 37-2009. Appendices A and A1 reference all
sections of the industry test standard except sections 1 (Purpose), 2
(Scope), and 4 (Classifications).
2. Double-Duct Systems
As discussed in section III.B.3 of this final rule, double-duct
systems are equipment classes of ACUACs and ACUHPs, either single
package or split, designed for indoor installation in constrained
spaces, such that outdoor air must be ducted to and from the outdoor
coil.
Pursuant to the current DOE test procedure (which references ANSI/
AHRI 340/360-2007), double-duct systems are tested and rated under the
same test conditions at zero outdoor air ESP as conventional ACUACs and
ACUHPs (i.e., that are not double-duct systems). AHRI 340/360-2022
includes two different set of test provisions that can be used for
testing double-duct systems. Section 6.1.3.7 of AHRI 340/360-2022
includes provisions for measuring performance at zero outdoor air ESP
to determine the EER, IEER, and/or COP metrics, consistent with the
current DOE test procedure. AHRI 340/360-2022 added an additional test
method in appendix I for double-duct systems that specifies an outdoor
air ESP requirement of 0.50 in. H<INF>2</INF>O for double-duct systems.
When testing with 0.50 in. H<INF>2</INF>O outdoor air ESP, ratings are
designated with the subscript ``DD'' (e.g., EER<INF>DD</INF>,
COP<INF>DD</INF>, and IEER<INF>DD</INF>) to distinguish them from the
ratings determined by testing at zero outdoor air ESP. ASHRAE Standard
90.1-2022 does not include any separate provisions for double-duct
systems or the EER<INF>DD</INF>, COP<INF>DD</INF>, and/or
IEER<INF>DD</INF> metrics; therefore, testing per Appendix I to AHRI
340/360-2022 is not required per ASHRAE Standard 90.1-2022. As a
result, DOE's statutory obligation to consider the test procedures for
CUACs and CUHPs referenced in ASHRAE Standard 90.1 (per 42 U.S.C.
6314(a)(4)(A)) does not include Appendix I to AHRI 340/360-2022.
The ACUAC and ACUHP Working Group TP Term Sheet did not include
provisions for double-duct systems. However, the AHRI 1340-202X Draft
included provisions for determining the new IVEC and IVHE metrics for
double-duct systems. Specifically, similar to appendix I of AHRI 340/
360-2022, the AHRI 1340-202X Draft applied a 0.50 in. H<INF>2</INF>O
outdoor air ESP requirement for determining IVEC and IVHE for double-

[[Page 44003]]

duct systems. Other than this outdoor air ESP requirement, the AHRI
1340-202X Draft specified no differences in determining IVEC and IVHE
for double-duct systems as compared to conventional ACUACs and ACUHPs.
In the August 2023 TP NOPR, DOE proposed to: (1) maintain the existing
metrics for double-duct systems and reference AHRI 340/360-2022 for
double-duct systems in appendix A, and (2) adopt the IVEC and IVHE
metrics for double-duct systems in appendix A1 as specified in the AHRI
1340-202X Draft. 88 FR 56392, 56421-56422 (August 17, 2023).
In response, Carrier supported the adoption of the IVEC and IVHE
metric, as specified in AHRI 1340-202X, in appendix A1, as well as the
proposal to maintain the test procedure from AHRI 340/360-2022 in
appendix A without the provisions of appendix I of that test procedure.
(Carrier, No. 8 at p. 3) AHRI similarly supported the adoption of IVEC
and IVHE for double-duct systems in appendix A1. (AHRI, No. 15 at p. 2)
DOE notes that AHRI 1340-2023 maintains the same ESP conditions and
method for determining IVEC and IVHE for double-duct systems as the
method specified in the AHRI 1340-202X Draft. Because double-duct
systems are installed indoors with ducting of outdoor air to and from
the outdoor coil, DOE has concluded that testing at a non-zero outdoor
air ESP (as specified in the AHRI 1340-2023) would be more
representative of field applications than testing at zero outdoor air
ESP (as specified in the current Federal test procedure). DOE has also
concluded that the IVEC and IVHE metrics specified in AHRI 1340-2023
better capture actual energy use in the field than the COP, EER, and
IEER metrics specified in the current DOE test procedure, for the
reasons discussed throughout this final rule for ACUACs and ACUHPs more
generally. Further, DOE has concluded that the application of the IVEC
and IVHE metrics in AHRI 1340-2023 to double-duct systems reflect
industry consensus that these metrics are suitable for double-duct
systems. For these reasons and given the support expressed by
stakeholders, DOE is adopting the provisions in AHRI 1340-2023 for
determining IVEC and IVHE for double-duct systems in appendix A1.
As mentioned previously, the current cooling energy conservation
standards for double-duct systems are in terms of EER and the current
heating energy conservation standards are in terms of COP. Testing to
the IVEC and IVHE metrics will not be required until such time as
compliance is required with amended energy conservation standards for
double-duct systems denominated in terms of IVEC and IVHE, should DOE
adopt such standards. As discussed, DOE is also updating the current
test procedure for all CUACs and CUHPs, including double-duct systems,
in appendix A to reference AHRI 340/360-2022, maintaining the current
EER and COP metrics until the compliance date of any energy
conservation standards for double-duct systems denominated in terms of
IVEC and IVHE. As discussed, ASHRAE Standard 90.1-2022 does not include
any provisions specific to double-duct systems or standards denominated
in terms of the EER<INF>DD</INF>, COP<INF>DD</INF>, and/or
IEER<INF>DD</INF> metrics; therefore, testing double-duct systems at
non-zero outdoor air ESP per Appendix I to AHRI 340/360-2022 which
generates results in terms of EER<INF>DD</INF>, COP<INF>DD</INF>, and/
or IEER<INF>DD</INF> (as opposed to testing a zero outdoor air ESP per
section 6.1.3.7 of AHRI 340/360-2022 which generates results in terms
of EER, COP, and/or IEER) is not required per ASHRAE Standard 90.1-
2022. As a result, DOE's statutory obligation to consider the test
procedures for CUACs and CUHPs referenced in ASHRAE Standard 90.1 (per
42 U.S.C. 6314(a)(4)(A)) does not include Appendix I to AHRI 340/360-
2022.
3. ECUACs and WCUACs
a. Overall
The current DOE test procedure for ECUACs and WCUACs is specified
at 10 CFR 431.96 and includes the EER metric. The ACUAC and ACUHP
Working Group TP Term Sheet does not include provisions for ECUACs and
WCUACs. However, the AHRI 1340-202X Draft includes provisions for
determining the new IVEC and optional EER2 metric for ECUACs and
WCUACs. The AHRI 1340-202X Draft and AHRI 1340-2023 provisions for
determining IVEC and EER2 for ECUACs and WCUACs are largely the same as
the provisions for ACUACs and ACUHPs; however, there are several
provisions specific or unique to ECUACs and WCUACs, specifically
regarding: (1) ESP requirements, (2) test temperatures, and (3)
accounting for power of WCUAC heat rejection components.
In the August 2023 TP NOPR, DOE proposed to adopt the IVEC metric
for ECUACs and WCUACs in appendix A1, as specified in the AHRI 1340-
202X Draft, and sought comment on this proposal, including the test
temperature requirements. 88 FR 56392, 56419-56420 (August 17, 2023).
In response to the August 2023 TP NOPR, Carrier supported the
adoption of the IVEC metric for ECUACs and WCUACs in appendix A1 as
specified in the proposed AHRI 1340-202X Draft. (Carrier, No. 8 at p.
2) Carrier also commented that the working version of AHRI 1340 (at the
time of Carrier's comment) included updated test temperatures for
determining IVEC and EER2 for ECUACs and WCUACs, and Carrier presented
these updated test conditions. (Id.) AHRI also expressed support for
DOE's proposal to adopt the IVEC and IVHE metrics for ECUACs and
WCUACs. (AHRI, No. 15 at pp. 2, 5)
Trane supported the product classifications and water temperatures
for WCUACs in AHRI 1340 but did not support adopting the IVEC metric
for WCUACs as specified in AHRI 1340. Trane further stated that issues
specific to WCUACs need to be addressed in order to adopt an IVEC
metric for WCUACs that is truly representative of field applications.
Trane asserted that the provisions in AHRI 1340 do not adequately
consider the difference between indoor and outdoor single package units
and stated that the vast majority of WCUACs are indoor packaged units.
Trane further commented that WCUACs installed indoors most often use
waterside economizers rather than airside economizers and are typically
installed in the core of a multi-story office building, such that
outdoor air for economizing or ventilation is not introduced through
the WCUAC air handling section. Trane also commented that because
WCUACs typically distribute conditioned air only within a single floor
of a building, duct runs are typically shorter than for traditional
rooftop systems, and, therefore, the ESP conditions included in AHRI
1340 should be different for WCUACs. (Trane, No. 14 at pp. 3-4)
Regarding Trane's concerns about the IVEC metric for WCUACs, DOE
acknowledges that WCUACs have a range of applications that may not
always align with the assumptions included in the analyses to develop
the IVEC metric. However, DOE notes that this is also true for ACUACs
and ACUHPs, which serve a wide range of applications and operate in a
wide variety of different operating conditions. The intent of the IVEC
metric, as developed by the Working Group, was to representatively
capture performance of the U.S. national average of CUAC and CUHP
applications, understanding that this ``average performance'' cannot
perfectly represent the unique aspects of certain applications. DOE
notes that the IVEC metric is specified for WCUACs in the recently
published industry consensus test procedure AHRI 1340-

[[Page 44004]]

2023 consistent with DOE's proposals (with certain updated test
conditions, as discussed). Therefore, DOE understands AHRI 1340-2023
and the IVEC metric specified in the test procedure to represent
general industry consensus on a representative test procedure and
metric for CUACs and CUHPs, including WCUACs.
AHRI 1340-2023 includes updates to the provisions for determining
IVEC for ECUACs and WCUACs--specifically, the test temperature and
accounting for power of WCUAC heat rejection components. The ESP
requirements specified for ECUACs and WCUACs are unchanged from the
AHRI 1340-202X Draft. These provisions are discussed in detail in the
following subsections. DOE has concluded that the IVEC metric specified
in AHRI 1340-2023 for ECUACs and WCUACs (including the ESP
requirements, updated test temperatures, and updated WCUAC heat
rejection component power allowances) is consistent with the proposed
adoption of the IVEC metric specified in the AHRI 1340-202X Draft and
meets the criteria in 42 U.S.C. 6314(a)(2)-(3). Accordingly, DOE is
adopting the IVEC metric (as well as the optional EER2 metric) and
associated test provisions specified in AHRI 1340-2023 in appendix A1
for ECUACs and WCUACs.
As mentioned previously, the current energy conservation standards
for ECUACs and WCUACs are in terms of EER. Testing to the IVEC metric
will not be required until such time as compliance is required with
amended energy conservation standards for ECUACs and WCUACs denominated
in terms of IVEC, should DOE adopt such standards. As discussed, DOE is
also updating the current test procedure for all CUACs and CUHPs,
including ECUACs and WCUACs, in appendix A to reference AHRI 340/360-
2022, maintaining the current EER metric until the compliance date of
any energy conservation standards for ECUACs and WCUACs denominated in
terms of the IVEC metric. As discussed in section III.C.1 of this final
rule, DOE has concluded that this amendment in Appendix A is consistent
with the intent of the test procedure references for ECUACs and WCUACs
in the latest published version of ASHRAE Standard 90.1.
b. ESP Requirements for ECUACs and WCUACs
The IVEC and EER2 metrics include higher ESP requirements than the
current DOE test procedures and AHRI 340/360-2022. For ECUACs and
WCUACs with cooling capacity greater than or equal to 65,000 Btu/h, the
AHRI 1340-202X Draft specifies the same ESP requirements for
determining IVEC and EER2 for ECUACs and WCUACs as for ACUACs and
ACUHPs. For ECUACs and WCUACs with cooling capacity less than 65,000
Btu/h, there are no air-cooled equipment of comparable cooling capacity
within the scope of the AHRI 1340-202X Draft. Therefore, the AHRI 1340-
202X Draft includes an ESP requirement of 0.5 in. H<INF>2</INF>O for
testing ECUACs and WCUACs with cooling capacity less than 65,000 Btu/h,
which is consistent with the ESP requirement specified in AHRI 210/240-
2023 for comparable air-cooled equipment (i.e., air-cooled, three-phase
CUACs and CUHPs with cooling capacity less than 65,000 Btu/h). As
discussed in the August 2023 TP NOPR, DOE understood that the
provisions for determining IVEC and EER2 for ECUACs and WCUACs,
specifically including the higher ESP requirements outlined in the AHRI
1340-202X Draft, reflect industry consensus that the IVEC metric (and
optional EER2 metric) provide a more representative measure of energy
efficiency for ECUACs and WCUACs. 88 FR 56392, 56419-56420 (August 17,
2023). AHRI 1340-2023 maintains the same ESP requirements as those
outlined in the AHRI 1340-202X Draft. In this final rule, DOE maintains
its conclusion that the ESP requirements specified for ECUACs and
WCUACs in AHRI 1340-2023 are representative of field installations for
ECUACs and WCUACs. As such, DOE is adopting the ESP requirements for
testing ECUACs and WCUACs as outlined in AHRI 1340-2023.
c. ECUAC and WCUAC Test Temperatures and WCUAC Heat Rejection
Components
ECUACs and WCUACs use different test temperatures than ACUACs and
ACUHPs, and in the August 2023 TP NOPR, DOE presented test temperature
requirements for full-load and part-load test points for determining
IVEC for ECUACs and WCUACs, as specified in the AHRI 1340-202X Draft.
88 FR 56392, 56419-56420 (August 17, 2023).
WCUACs are typically installed in the field with separate heat
rejection components \16\ that reject heat from the water loop to
outdoor ambient air, but these separate heat rejection components are
not installed nor is their power measured during testing of WCUACs
under the current DOE test procedure. These heat rejection components
typically consist of a circulating water pump (or pumps) and a cooling
tower. To account for the power that would be consumed by these
components in field installations, section 6.1.1.7 of AHRI 340/360-2022
specifies that WCUACs with cooling capacities less than 135,000 Btu/h
shall add 10.0 W to the total power of the unit for every 1,000 Btu/h
of cooling capacity.
---------------------------------------------------------------------------

\16\ Separate heat rejection components (e.g., a cooling tower
or circulating water pump) are required for WCUACs but not used with
ACUACs or ECUACs. ACUACs and ECUACs contain all components needed to
reject heat to the ambient air surrounding the ACUAC or ECUAC.
WCUACs, however, reject heat to a building's water loop. Separate
components are needed to circulate the water in the water loop and
reject heat from the water loop to the ambient air surrounding the
building.
---------------------------------------------------------------------------

Section 6.2.4.3 of the AHRI 1340-202X Draft includes similar
provisions for accounting for the power of heat rejection components
for WCUACs to those in AHRI 340/360-2022. However, unlike AHRI 340/360-
2022, the heat rejection component power addition was not limited to
units with cooling capacities less than 135,000 Btu/h in the AHRI 1340-
202X Draft, and instead, it applied to WCUACs of all cooling
capacities. DOE proposed the adoption of the approach specified in the
AHRI 1340-202X Draft in the August 2023 TP NOPR. 88 FR 56392, 56420-
56421 (August 17, 2023).
As noted by Carrier's comment (summarized in section III.E.3.a of
this document), based on further discussions and analysis in AHRI
Commercial Unitary STC meetings after the issuance of the AHRI 1340-
202X Draft, the test conditions for ECUACs and WCUACs were updated in
the published AHRI 1340-2023. Additionally, AHRI 1340-2023 includes
different values to account for the power of heat rejection components
of WCUACs as compared to the AHRI 1340-202X Draft. Both of these
changes were related to a changed assumption in operation of cooling
towers in water loops serving WCUACs.
The analysis conducted to develop the heat rejection component
power adder and the WCUAC entering water temperature (``EWT'') test
conditions in the AHRI 1340-202X Draft assumed constant cooling tower
fan speed regardless of load level. In other words, the analysis to
develop the AHRI 1340-202X Draft method assumed that the cooling tower
fans do not slow down when there is less heat to reject in the cooling
tower, and thus: (1) the cooling tower fan power does not reduce at
lower load levels; and (2) the cooling tower approach \17\ reduces
significantly

[[Page 44005]]

at lower load levels. Specifically, as the cooling load reduces, the
same amount of cooling tower airflow is being provided to reject less
heat in the cooling tower, so the water is cooled in the cooling tower
to a temperature closer to the outdoor air wet-bulb temperature, and,
therefore, the water leaving the cooling tower (and entering the WCUAC)
is at a lower temperature, resulting in a lower WCUAC EWT test
condition.
---------------------------------------------------------------------------

\17\ For an evaporative cooling tower, the ``cooling tower
approach'' is the difference between the cold water temperature
(i.e., the temperature of the cooled water leaving the cooling
tower) and the outdoor air wet-bulb temperature.
---------------------------------------------------------------------------

The analysis conducted to develop the heat rejection component
power adder and the WCUAC EWT test conditions in AHRI 1340-2023 assumes
that variable frequency drives (``VFDs'') are used on cooling tower
fans to reduce cooling tower fan speed (and thus cooling tower fan
power) for lower cooling loads. The use of VFDs on cooling tower fans
impacts both the cooling tower fan power and the WCUAC EWT. First, the
cooling tower fan VFD reduces cooling tower fan power at part load.
Therefore, instead of a single power adder in W per 1,000 Btu/h of
cooling capacity applied regardless of the test being conducted (i.e.,
independent of the test bin) as specified in the AHRI 1340-202X Draft,
AHRI 1340-2023 includes four different condenser tower fan and pump
power rate adders (in units of W per 1,000 Btu/h of cooling capacity)--
a separate adder for each test bin, with the adders decreasing at lower
load levels. Second, the reduced cooling tower fan speed at part load
means that the cooling tower approach does not significantly reduce at
lower load levels, because cooling tower airflow driving heat transfer
in the cooling tower reduces along with the amount of heat
rejected.\18\ Correspondingly, the WCUAC part-load EWT test conditions
in AHRI 1340-2023 are higher than the EWT test conditions in the AHRI
1340-202X Draft. The EWT test conditions for WCUACs in AHRI 1340-2023,
which were developed based on the assumption that VFDs are used on
cooling tower fans to reduce cooling tower fan speed, are the same as
those included in Carrier's comment (Carrier, No. 8 at p. 2) in
response to the August 2023 TP NOPR.
---------------------------------------------------------------------------

\18\ For the AHRI 1340-2023 EWTs, the assumed cooling tower
approach is the same for B, C, and D bins -i.e., as shown in Table
III-3 and Table III-4, the difference between the outdoor air wet-
bulb temperature in Table III-3 and the EWT in Table III-4 is 8
[deg]F for the B, C, and D bins. Therefore, the EWT test conditions
in AHRI 1340-2023 decrease for each part-load bin by the same amount
as the outdoor air wet-bulb temperature test conditions.
---------------------------------------------------------------------------

Additionally, AHRI 1340-2023 includes slight changes to the outdoor
air wet-bulb temperature test conditions for ECUACs, based on updated
analysis of representative temperatures. The outdoor air wet-bulb
temperature requirements for ECUACs in AHRI 1340-2023 are the same as
those included in Carrier's comment (Carrier, No. 8 at p. 2) in
response to the August 2023 TP NOPR.
Table III-3 and Table III-4 show the test temperatures included in
the AHRI 1340-202X Draft and the final test temperatures included in
AHRI 1340-2023 for ECUACs and WCUACs, respectively.
[GRAPHIC] [TIFF OMITTED] TR20MY24.130

[GRAPHIC] [TIFF OMITTED] TR20MY24.131

[[Page 44006]]

Regarding the minor revisions to the ECUAC outdoor air wet-bulb
temperatures in AHRI 1340-2023, DOE has concluded that these updated
temperatures are representative of applications for ECUACs, and that
adopting these slight updates to the proposed ECUAC test temperatures
is consistent with the intent of the proposed approach and with
comments from Carrier that included these updated temperatures.
Therefore, in this final rule, DOE is adopting the ECUAC test
temperatures specified in AHRI 1340-2023.
Regarding the test temperatures and heat rejection component power
for WCUACs, DOE has concluded that VFDs are typically used on cooling
tower fans to reduce cooling tower fan speed with reduced cooling load,
and, therefore, concludes that assuming the presence of cooling tower
fan VFDs is a more representative basis for determining the WCUAC EWTs
and tower fan and pump power rate or ``TFPPR'' adders. Additionally,
DOE has concluded that the updates to the approach in AHRI 1340-2023
(i.e., updated WCUAC test temperatures and updated TFPPR approach) are
generally consistent with the approach proposed in the August 2023 TP
NOPR, but with more representative technical details. Further, DOE
concludes that adopting the updated WCUAC test temperatures (and, thus,
generally, the updated approach for developing WCUAC test temperatures
and TFPPR values that assumes cooling tower fan VFDs) is consistent
with comments from Carrier that included these updated temperatures.
However, DOE is aware of three issues in the WCUAC heat rejection
components power adders (referred to in AHRI 1340-2023 as the TFPPR)
used in Table 7 to AHRI 1340-2023. The first issue is a mismatch
between how the TFPPR values were developed and how they were
implemented in AHRI 1340-2023. Specifically, the TFPPR values in Table
7 to AHRI 1340-2023 were determined based on the full-load cooling
capacity; therefore, the TFPPR value for each bin was intended to be
multiplied by the full-load capacity. However, the approach implemented
in AHRI 1340-2023 is inconsistent with these values--specifically,
equations 8, 10, 11, and 13 specify to multiply the TFPPR by the
cooling capacity determined for the test(s) performed for a given
cooling bin. Because part-load cooling capacities are lower than full-
load cooling capacities, multiplying the TFPPR value for a part-load
cooling bin by the part-load capacity for that bin results in an
unrepresentatively low tower fan and pump power calculated for the bin.
To resolve this issue, DOE has concluded that the values should instead
be based on the target cooling capacity for each part-load cooling bin,
which aligns with the approach in equations 8, 10, 11, and 13 of AHRI
1340-2023 (i.e., multiplying the TFPPR values by the measured cooling
capacity for each bin).
The second issue is that the full-load cooling tower fan power was
developed without consideration of the cooling tower fan motor
efficiency; therefore, the calculation reflected a fan motor efficiency
of 100 percent. Because 100 percent is a physically impossible motor
efficiency (and, therefore, underestimates the amount of power a fan
motor consumes), DOE has concluded that the TFPPR values should include
a more representative (i.e., lower) full-load fan motor efficiency.
The third issue is that the TFPPR values in AHRI 1340-2023 are
based on an unrepresentatively low fan power at low loads.
Specifically, the fan power was assumed to decrease cubically with
decreasing cooling load.\19\ However, this assumption does not account
for VFD, motor, and transmission losses which do not decrease cubically
with decreasing cooling load. At low cooling load (e.g., for the D
bin), this significantly underestimates cooling tower fan power because
the VFD, motor, and transmission losses are underestimated. DOE has
concluded that a more representative approach would be to account for
the VFD, motor, and transmission losses when developing the
relationship between cooling tower fan power and load. Accounting for
these losses impacts the TFPPR values for the B, C, and D part-load
bins.
---------------------------------------------------------------------------

\19\ The theoretical fan laws indicate that fan power decreases
cubically with decreasing fan speed. It was assumed that cooling
tower fan speed is proportional to cooling load (i.e., heat to be
rejected in the cooling tower), and, therefore, that cooling tower
fan power decreases cubically with decreasing cooling load.
---------------------------------------------------------------------------

Corrected TFPPR values that address these three issues with the
values published in AHRI 1340-2023 are shown in Table III-5. DOE
understands that the AHRI Commercial Unitary STC also plans to address
the aforementioned issues with the TFPPR values that were published in
AHRI 1340-2023. DOE expects that AHRI will consider including the
corrected TFPPR values shown in Table III-5 and adopted in this final
rule in a future version of AHRI 1340.
[GRAPHIC] [TIFF OMITTED] TR20MY24.132

For the reasons discussed in detail in the previous paragraphs, DOE
has concluded that the updated TFPPR values shown in Table III-5 are
generally consistent with the approach proposed in the August 2023 TP
NOPR, but that the corrected TFPPR values provide a more representative
accounting of WCUAC heat rejection component power than the values
published in AHRI 1340-2023 or the AHRI 1340-202X Draft.
For these reasons, DOE is adopting the updated WCUAC IVEC test
temperatures for IVEC in AHRI 1340-2023 and the TFPPR approach in AHRI
1340-2023 as modified by the revised TFPPR values shown in Table III-5.
4. IVHE for Colder Climates
As discussed in the August 2023 TP NOPR (see 88 FR 56392, 56416
(August 17, 2023)), it is likely that in the future manufacturers will
develop CUHPs that

[[Page 44007]]

are designed for operation in colder climates, and correspondingly that
the market for CUHPs in colder climates is expected to grow. Because
the IVHE metric is based on the US national average climate across all
US climate zones, the lowest bin temperature for calculating IVHE is
15.9 [deg]F, and a small fraction of heating hours are at colder
temperatures (i.e., 19 percent of heating hours are in a load bin with
a temperature colder than 32 [deg]F, and less than 1 percent of heating
hours are in a load bin with a temperature colder than 17 [deg]F).
As a result, the AHRI 1340-202X Draft includes provisions that are
distinct from the provisions used for IVHE, including weighting factors
and temperature bins, for calculating a colder climate-specific IVHE
metric, designated as IVHE<INF>C</INF>. Specifically, IVHE<INF>C</INF>
was developed using the same building heating analysis that was used to
develop IVHE (as discussed in section III.D.2 of this final rule), but
the IVHE<INF>C</INF> weighting factors and load bins were developed
using the results for climates zones 5 and above (i.e., climate zone 5
as well as all climate zones colder than climate zone 5), weighted by
the share of the U.S. population in each of those climate zones. The
use of only climate zones 5 and colder for IVHE<INF>C</INF> results in
the following, compared to IVHE: lower outdoor dry-bulb temperature for
each load bin, more heating season hours in all load bins, and a higher
heating season building load. Specifically, for IVHE<INF>C</INF>, 56
percent of heating hours are in a load bin with a temperature colder
than 32 [deg]F, and 12 percent of heating hours are in a load bin with
a temperature colder than 17 [deg]F. Further, because the defrost
degradation coefficients specified in appendix C of the ACUAC and ACUHP
Working Group TP Term Sheet depend on the outdoor temperature for each
load bin (and IVHE<INF>C</INF> has colder bin temperatures than IVHE),
the AHRI 1340-202X Draft also specifies separate defrost degradation
coefficients for calculating IVHE<INF>C</INF>. In the August 2023 TP
NOPR, DOE proposed to adopt provisions for determining the
IVHE<INF>C</INF> metric in appendix A1 via reference to the AHRI 1340-
202X Draft and to allow for optional representations of
IVHE<INF>C</INF> for CUHPs. 88 FR 56392, 56416 (August 17, 2023).
In response to the August 2023 TP NOPR, NEEA and NYSERDA supported
DOE's proposal to include in the test procedure and allow optional
representations of the colder climate IVHE<INF>C</INF>. (NEEA, No. 16
at pp. 2-3; NYSERDA, No. 13 at p. 2)
Given the potential for the development of CUHPs designed for
operation in colder climates and the expected increased number of
shipments of CUHPs into colder climates, DOE recognizes the utility in
having CUHP ratings for a separate IVHE metric that is specific to
colder climates. AHRI 1340-2023 includes provisions for determining
IVHE<INF>C</INF> that are generally consistent with the AHRI 1340-202X
Draft, with the additional specificity discussed in section III.E.8 of
this final rule. Correspondingly, DOE has concluded that the
IVHE<INF>C</INF> metric as specified in AHRI 1340-2023 (including the
minor updates in the published AHRI 1340-2023 that provide additional
specificity as discussed in section III.E.8 of this document) is more
representative of field conditions for CUHPs installed in colder US
climates. Therefore, DOE is adopting provisions for determining the
IVHE<INF>C</INF> metric in appendix A1 via reference to AHRI 1340-2023
and allowing for optional representations of IVHE<INF>C</INF> for
CUHPs. Specifically, DOE is amending the test procedure so that IVHE
will be the regulated heating metric when testing to appendix A1;
therefore, should DOE adopt amended standards for CUHPs denominated in
terms of IVEC and IVHE, all CUHPs will be required to certify
compliance with IVHE standards, and additional representations of
IVHE<INF>C</INF> will be optional.
5. Test Conditions Used for Current Metrics in Appendix A
AHRI 340/360-2022 designates certain test conditions for test
procedures characterized as ``standard rating tests'' and certain other
test conditions for test procedures characterized as ``performance
operating tests.'' The ``standard rating tests'' are used for
determining representations of cooling capacity, heating capacity, and
cooling and heating efficiencies. The ``performance operating tests''
evaluate other operating conditions, such as ``maximum operating
conditions'' (see section 8 of AHRI 340/360-2022). Specifically, Table
6 of AHRI 340/360-2022 specifies test conditions for standard rating
and performance operating tests for CUACs and CUHPs. The relevant
conditions for EER and IEER cooling tests are those referred to as
``standard rating conditions'' in AHRI 340/360-2022.
To clarify this distinction and consistent with its proposal to
adopt AHRI 340/360-2022 in appendix A, DOE proposed in the August 2023
TP NOPR to specify explicitly in section 3 of appendix A that the
cooling test conditions used for representations as required under the
DOE regulations would be: (1) for equipment subject to standards in
terms of EER, the ``Standard Rating Conditions, Cooling'' conditions
specified in Table 6 of AHRI 340/360-2022; and (2) for equipment
subject to standards in terms of IEER, the ``Standard Rating
Conditions, Cooling'' and ``Standard Rating Part-Load Conditions
(IEER)'' conditions specified in Table 6 of AHRI 340/360-2022. 88 FR
56392, 56412 (August 17, 2023).
For heating mode tests of CUHPs, Table 6 of AHRI 340/360-2022
includes ``Standard Rating Conditions'' for both a ``High Temperature
Steady-state Test for Heating'' and a ``Low Temperature Steady-state
Test for Heating'' (conducted at 47 [deg]F and 17 [deg]F outdoor air
dry-bulb temperatures, respectively). To clarify which conditions are
applicable for representations as required under the DOE regulations
and consistent with its proposal to adopt AHRI 340/360-2022 in appendix
A, DOE proposed to specify explicitly in section 3 of appendix A that
the heating test conditions used for compliance are the ``Standard
Rating Conditions (High Temperature Steady-state Heating)'' conditions
specified in Table 6 of AHRI 340/360-2022. Further, DOE proposed to
include the low-temperature (i.e., 17 [deg]F) heating test condition
specified in Table 6 of AHRI 340/360-2022 (referred to as ``Low
Temperature Steady-state Heating'') and specify in section 3 of
appendix A that representations of COP at this low-temperature heating
condition are optional. 88 FR 56392, 56412 (August 17, 2023).
DOE did not receive any comments in response to these proposals.
Therefore, DOE is adopting the specification of the relevant test
conditions in AHRI 340/360-2022 in appendix A as proposed. These
amendments in appendix A are consistent with the test requirements
referenced in the latest version of ASHRAE Standard 90.1.
6. Test Conditions Used for New Metrics in Appendix A1
Consistent with DOE's proposal to adopt the AHRI 1340-202X Draft
for determining IVEC and IVHE, as discussed more fully in the August
2023 TP NOPR, DOE proposed to specify in section 3 of the proposed
appendix A1 which test conditions in the AHRI 1340-202X Draft would be
required and optional for rating to IVEC and IVHE. 88 FR 56392, 56412-
56413 (August 17, 2023). DOE also proposed to include provisions for
optional representations of the full-load efficiency metrics, EER2,
COP2<INF>47</INF>, COP2<INF>17</INF>, and COP2<INF>5</INF>, and
specified the test conditions required for these optional
representations. Id. DOE did not receive any comments regarding

[[Page 44008]]

the proposed approach for specifying the required and optional test
conditions. The test conditions in AHRI 1340-2023 align with those in
the AHRI 1340-202X Draft except for certain test conditions for ECUACs
and WCUACs, which are discussed in section III.E.3 of this final rule.
Therefore, DOE is adopting the specification of test conditions in
appendix A1 as proposed, referencing the corresponding test conditions
in the published AHRI 1340-2023.
7. Provisions Introduced in the AHRI 1340-202X Draft
The AHRI 1340-202X Draft proposed for adoption in the August 2023
TP NOPR includes several provisions regarding the new IVEC and IVHE
metrics that are not included in the ACUAC and ACUHP Working Group TP
Term Sheet. DOE notes that the ACUAC and ACUHP Working Group TP Term
Sheet includes provisions to allow changes to the recommendations in
the term sheet if mistakes in the original recommendations are
identified through further analysis or discussion between stakeholders.
(See EERE-2022-BT-STD-0015-0065, Recommendations #2, #8, #11) Further,
the AHRI 1340-202X Draft includes a number of additional test
provisions that arose as a result of discussions between many
interested stakeholders participating in the AHRI Commercial Unitary
STC and that DOE has concluded are consistent with the intent of the
ACUAC and ACUHP Working Group TP Term Sheet but provide additional
guidance for determining IVEC and IVHE. DOE included discussion of
provisions regarding the topics discussed in the following sub-sections
in the August 2023 TP NOPR and proposed to adopt the provisions in the
AHRI 1340-202X Draft regarding all of these topics. 88 FR 56392, 56416-
56419 (August 17, 2023). DOE did not receive comment regarding the
provisions in the AHRI 1340-202X Draft addressing these topics, and
these provisions are also included in the published AHRI 1340-2023,
consistent with DOE's proposals in the August 2023 TP NOPR. As
discussed, DOE is adopting AHRI 1340-2023 for determining IVEC and IVHE
in appendix A1, including these additional provisions not specified in
the ACUAC and ACUHP Working Group TP Term Sheet, consistent with
proposals in the August 2023 TP NOPR. The following sections discuss
these provisions in further detail.
a. Cooling Weighting Factors Adjustment
Subsequent to the development of the ACUAC and ACUHP Working Group
TP Term Sheet, additional analysis of the building models used to
develop the weighting factors for the IVEC metric indicated that the
recommended weighting hours included in the ACUAC and ACUHP Working
Group TP Term Sheet are incorrect. Specifically, the weighting hour
factors in the ACUAC and ACUHP Working Group TP Term Sheet over-
represent mechanical-only cooling hours and underrepresent economizer-
only and integrated-economizer hours for all IVEC load bins. DOE
presented corrected weighting factors during the ACUAC and ACUHP
standards negotiations, and no concerns were raised. (See EERE-2022-BT-
STD-0015-0078 at p. 8) These corrected IVEC weighting factors were
included in the AHRI 1340-202X Draft and remain the same in AHRI 1340-
2023. DOE is adopting AHRI 1340-2023 for determining IVEC and IVHE in
appendix A1, including these updated IVEC weighting factors.
b. ESP Testing Target Calculation
Recommendation #12 of the ACUAC and ACUHP Working Group TP Term
Sheet includes an equation for determining adjusted ESP for cooling or
heating tests that use an airflow that differs from the full-load
cooling airflow. However, the equation specified in Recommendation #12
is missing a term for the full-load ESP. This equation was corrected in
the AHRI 1340-202X Draft and remains the same in AHRI 1340-2023. DOE is
adopting AHRI 1340-2023 for determining IVEC and IVHE in appendix A1,
including this corrected equation for determining adjusted ESP.
c. Test Instructions for Splitting ESP Between Return and Supply Duct
As discussed previously, Recommendation #12 of the ACUAC and ACUHP
Working Group TP Term Sheet specifies that ESP shall be split between
return and supply ducts during testing, such that 25 percent of the ESP
is applied in the return ductwork. However, the ACUAC and ACUHP Working
Group TP Term Sheet does not contain explicit test se-tup instructions
specifying how to achieve the split in ESP between return and supply
ductwork. Section E11 in appendix E of the AHRI 1340-202X Draft and
section E11 in appendix E of AHRI 1340-2023 include more detailed
instructions regarding the duct and pressure measurement set-up, the
measurement and adjustment of the return static pressure, and the
restriction devices that can be used in the return ductwork to achieve
the required split of between 20 and 25 percent of the total ESP
applied to the return ductwork. The AHRI 1340-202X Draft and AHRI 1340-
2023 also include the same test instructions for cases in which the ESP
split is not achieved in the first test, as well as any exceptions to
the specified tolerance requirement. DOE has concluded that these
additional instructions provide a more consistent measurement of ESP
and are aligned with the intent of Recommendation #12 of the ACUAC and
ACUHP Working Group TP Term Sheet. Therefore, DOE is adopting these
provisions of AHRI 1340-2023 for determining IVEC and IVHE.
d. Default Fan Power and Maximum Pressure Drop for Coil-Only Systems
DOE's current test procedure for CUACs and CUHPs references ANSI/
AHRI 340/360-2007, and section 6.1 of that test standard specifies
default fan power and corresponding capacity adjustment for ACUACs,
ACUHPs, ECUACs, and WCUACs with a coil-only configuration (i.e.,
without an integral indoor fan). Specifically, ANSI/AHRI 340/360-2007
requires that an indoor fan power of 365 Watts (``W'') per 1,000
standard cubic feet per minute (``scfm'') be added to power input for
coil-only units and that the corresponding heat addition (i.e., 1,250
Btu/h per 1,000 scfm) be subtracted from measured cooling capacity (and
added to measured heating capacity), regardless of the capacity of the
unit under test and regardless of full-load or part-load test
conditions.
Section 6.1.1.6 of AHRI 340/360-2022 has the same requirement as
ANSI/AHRI 340/360-2007 regarding default fan power and capacity
adjustment of coil-only systems. Additionally, both section 6.1.3.2(d)
of ANSI/AHRI 340/360-2007 and section 6.1.3.3.4 of AHRI 340/360-2022
specify that for coil-only systems, the pressure drop across the indoor
assembly shall not exceed 0.30 in. H<INF>2</INF>O for the full-load
cooling test. If the measured pressure drop exceeds that value, then
the industry test standards specify that the indoor airflow rate be
reduced such that the measured pressure drop does not exceed the
specified maximum pressure drop.
The AHRI 1340-202X Draft included different requirements for
testing coil-only units as compared to ANSI/AHRI 340/360-2007 and AHRI
340/360-2022. First, section 5.17.4 of the AHRI 1340-202X Draft
includes a higher maximum pressure drop across the indoor assembly of
1.0 in. H<INF>2</INF>O when testing

[[Page 44009]]

coil-only units, as compared to the maximum pressure drop of 0.3 in.
H<INF>2</INF>O specified in ANSI/AHRI 340/360-2007 and AHRI 340/360-
2022. Second, section 6.2.4.2 of the AHRI 1340-202X Draft includes
higher default fan power values than specified in ANSI/AHRI 340/360-
2007 and AHRI 340/360-2022; these values were updated to reflect the
higher ESP requirements used for IVEC and IVHE. Because the ACUAC and
ACUHP Working Group TP Term Sheet and the AHRI 1340-202X Draft specify
ESP requirements that vary by capacity bin, section 6.2.4.2 of the AHRI
1340-202X Draft specifies different default fan power adders and
capacity adjustments for each capacity bin, developed based on fan
power needed to overcome the ESP requirement for each bin. DOE proposed
in the August 2023 TP NOPR to adopt the default fan power adders and
capacity adjustments included in the AHRI 1340-202X Draft in appendix
A1. 88 FR 56392, 56417 (August 17, 2023).
Lastly, while ANSI/AHRI 340/360-2007 and AHRI 340/360-2022 specify
a single default fan power adder (and corresponding capacity
adjustment) to be used for all tests, the AHRI 1340-202X Draft included
separate default fan power adders and capacity adjustments for full-
load tests and part-load tests (i.e., tests conducted at an airflow
lower than the full-load cooling airflow) to reflect that fan power
does not decrease linearly with airflow (i.e., reducing airflow in
part-load operation would reduce fan power in field operation by more
than would be calculated using a single power adder that is normalized
by airflow). These part-load fan power adders and capacity adjustments
were developed assuming a part-load airflow that is 67 percent of the
full-load airflow. The AHRI 1340-202X Draft does not specify what
values to use if the part-load airflow is between 67 and 100 percent of
the full-load airflow. Alongside proposing to adopt the fan power
adders specified in the AHRI 1340-202X Draft in the August 2023 TP
NOPR, DOE proposed to adopt a linear interpolation approach in appendix
A1 in the case where the part-load airflow for coil-only CUACs and
CUHPs specified by a manufacturer for a test is between 67 and 100
percent of the full-load airflow, which would specify how to calculate
the default fan power coefficient and capacity adjustment in such
cases. 88 FR 56392, 56417 (August 17, 2023). The proposed approach is
consistent with the approach adopted for the residential CAC/HP test
procedure.\20\
---------------------------------------------------------------------------

\20\ The CAC/HP test procedure final rule was published in the
Federal Register on October 25, 2022, and can be found at 87 FR
64550.
---------------------------------------------------------------------------

Consistent with the basis of part-load values in the AHRI 1340-202X
Draft on 67 percent of full-load cooling airflow, DOE also proposed in
the August 2023 TP NOPR to clarify that for tests in which the
manufacturer-specified airflow is less than the full-load cooling
airflow, the target airflow for the test must be the higher of: (1) the
manufacturer-specified airflow for the test; or (2) 67 percent of the
airflow measured for the full-load cooling test. 88 FR 56392, 56417
(August 17, 2023).
AHRI 1340-2023 includes provisions consistent with those DOE
proposed to adopt for testing coil-only units in the August 2023 TP
NOPR. Id. Specifically, the already discussed maximum pressure drop and
capacity and fan power adjustments included in sections 5.17.4 and
6.2.4.2 of the AHRI 1340-202X Draft are included in sections 5.17.2 and
6.2.4.3 of AHRI 1340-2023. Additionally, AHRI 1340-2023 includes
provisions consistent with DOE's proposals regarding issues for testing
coil-only units not addressed in the AHRI 1340-202X Draft.
Specifically, section 6.2.4.2 of AHRI 1340-2023 includes the linear
interpolation method to address cases in which the part-load airflow
specified by a manufacturer for a test is between 67 and 100 percent of
the full-load airflow. Further, section 5.18.4.2 of AHRI 1340-2023
includes the clarification regarding which target airflow should be
used for tests in which the manufacturer-specified airflow is less than
the full-load cooling airflow.
Accordingly, DOE has concluded that the coil-only test procedure in
AHRI 1340-2023 aligns with the approach proposed in the August 2023 TP
NOPR and represents industry consensus on the most appropriate and
representative way to test and determine the IVEC and IVHE of coil-only
systems. Therefore, DOE is adopting these provisions of AHRI 1340-2023
for determining IVEC and IVHE for coil-only units.
e. Component Power Measurement
Section E10 of the AHRI 1340-202X Draft and AHRI 1340-2023 include
additional instruction regarding how the total unit, indoor fan,
controls, compressor, condenser section, and crankcase heat power
should be measured and accounted for during a test. This includes
details that were not included in the ACUAC and ACUHP Working Group TP
Term Sheet, as well as updates to address issues such as unique model
designs and power meter precision that were identified after the term
sheet was completed. For example, although the ACUAC and ACUHP Working
Group TP Term Sheet specified that controls power be determined by
subtracting all other power measurements from the total unit power,
sections E10.1 and E10.2 of both the AHRI 1340-202X Draft and AHRI
1340-2023 require that controls power be measured. This is because
controls power is a much smaller value than power consumed by other
components of a CUAC or CUHP and, thus, is more accurately determined
by measuring directly with a power meter of sufficient precision.
Section E10.2 of both the AHRI 1340-202X Draft and AHRI 1340-2023 also
allow for determination of compressor and condenser section power by
measurement together or by subtraction from total power (i.e., separate
power measurement of power consumed by the compressor and condenser
section is not required). These provisions address cases in which
unique wiring of certain models may make separate measurement of
compressor and condenser section power very difficult or impossible, in
addition to cases in which the laboratory does not have enough power
meters to measure all components separately. Section E10.3 of both the
AHRI 1340-202X Draft and AHRI 1340-2023 also provide an equation for
calculating default value(s) for crankcase heater power to address the
case in which a manufacturer does not specify crankcase heater
wattage.\21\ Because DOE has concluded that these provisions will
provide more repeatable and representative test results, DOE is
adopting AHRI 1340-2023 for determining IVEC and IVHE in appendix A1,
including these provisions for component power measurement.
---------------------------------------------------------------------------

\21\ As discussed, Recommendation #13 of the ACUAC and ACUHP
Working Group TP Term Sheet requires that manufacturers certify
crankcase heater wattage for each heater. DOE is not adopting
amendments to certification requirements in this rulemaking, and
will instead address certification requirements in a separate
rulemaking for certification, compliance, and enforcement.
---------------------------------------------------------------------------

f. Non-Standard Low-Static Indoor Fan Motors
As discussed in section III.D.1 of this document, DOE is adopting
higher ESPs recommended by the Working Group and included in AHRI 1340-
2023 in the appendix A1 Federal test procedure for CUACs and CUHPs.
However, individual models of CUACs and CUHPs with indoor fan motors
intended

[[Page 44010]]

for installation in applications with a low ESP may not be able to
operate at the adopted full-load ESP requirements at the full-load
indoor rated airflow. To address this situation, section 3.25 of the
AHRI 1340-202X Draft and section 3.2.30 of AHRI 1340-2023 both define
``non-standard low-static indoor fan motors'' as motors which cannot
maintain ESP as high as specified in the test procedure when operating
at the full-load rated indoor airflow and that are distributed in
commerce as part of an individual model within the same basic model
that is distributed in commerce with a different motor specified for
testing that can maintain the required ESP. Section 5.19.3.3 of the
AHRI 1340-202X Draft and section 5.19.3.3 of AHRI 1340-2023 include the
same test provisions for CUACs and CUHPs with non-standard low-static
indoor fan motors that cannot reach the ESP within tolerance during
testing, which require using the maximum available fan speed that does
not overload the motor or motor drive, adjusting the airflow-measuring
apparatus to maintain airflow within tolerance, and operating with an
ESP as close as possible to the minimum ESP requirements for testing.
This approach is consistent with the industry test standard referenced
by the DOE test procedure for DX-DOASes (AHRI 920-2020).
As discussed in section III.F.5.a of this document, DOE is
clarifying that representations for a CUAC or CUHP basic model must be
based on the least efficient individual model(s) distributed in
commerce within the basic model (with the exception specified in 10 CFR
429.43(a)(3)(vi)(A) for certain individual models with the components
listed in table 6 to 10 CFR 429.43(a)(3)). DOE has concluded that the
combination of: (1) the provisions in AHRI 1340-2023 for testing models
with ``non-standard low-static indoor fan motors'' with (2) the
requirement that basic models be rated based on the least efficient
individual model (with certain exceptions, as discussed) provides an
appropriate approach for handling CUAC and CUHP models with these
motors--if an individual model with a non-standard low-static indoor
fan motor is tested, the test will be conducted at an indoor airflow
representative for that model. But because testing at the rated airflow
for such an individual model will result in testing at an ESP lower
than the requirement and, thus, a lower indoor fan power, the
representations for that basic model will be required to be based on an
individual model with an indoor fan motor that can achieve the ESP
requirements at the rated airflow. Consistent with the adoption of AHRI
340/360-2023 in appendix A1, DOE is not deviating from the provisions
for testing models with non-standard low-static indoor fan motors.
g. IVHE Equations
Section 6.3 of the AHRI 1340-202X Draft and section 6.3 of AHRI
1340-2023 both include several changes regarding the heating metric
equations that differ from the provisions in appendix C of the ACUAC
and ACUHP Working Group TP Term Sheet. DOE has concluded that these
updated IVHE equations, described in the following paragraphs, provide
for a more accurate calculation of IVHE. Further, Recommendation #9 of
the ACUAC and ACUHP Working Group TP Term Sheet states that the
equations in appendix C of the term sheet are subject to quality
control checking (``QC'') for errors, with the intent remaining the
same as voted on. DOE has concluded that the discussed deviations in
the AHRI 1340-202X Draft and the published AHRI 1340-2023 hold the same
intent of the recommendations set forth in the ACUAC and ACUHP Working
Group TP Term Sheet. Therefore, DOE is adopting the provisions of AHRI
1340-2023 for determining IVHE in appendix A1, including the updated
equations discussed in this section.
1. Removal of the cut-out factor from certain equations: Appendix C
of the ACUAC and ACUHP Working Group TP Term Sheet includes a cut-out
factor in IVHE calculations to reflect the dependence of unit
performance on whether compressors are cut-out at a given bin
temperature. However, the cut-out factor was inadvertently included in
certain equations in appendix C of the ACUAC and ACUHP Working Group TP
Term Sheet where it should not apply (i.e., equations to determine unit
performance that should not be impacted by the fraction of time in
which compressors are cut out). Therefore, in the AHRI 1340-202X Draft
and AHRI 1340-2023, the cut-out factor is removed from those equations
where it was incorrectly applied in the ACUAC and ACUHP Working Group
TP Term Sheet. For all CUHPs that DOE is aware of on the market today,
the cut-in and cut-out temperatures are less than the temperature of
the lowest load bin. As such, the cut-out factor only applies when the
unit is operating at full-load capacity and does not affect the
calculation of IVHE.
2. Accounting for auxiliary heat when compressors are cut out: When
compressors are cut out, auxiliary heat would operate to meet the
building load. This auxiliary heat operation is addressed in section b
of appendix C of the ACUAC and ACUHP Working Group TP Term Sheet (i.e.,
when building load exceeds the highest stage unit heating capacity at a
given bin temperature), but was inadvertently excluded in sections c
and d of appendix C of the ACUAC and ACUHP Working Group TP Term Sheet
(i.e., when building load is between capacities of a unit tested with
multiple heating stages, or when building load is less than the
capacity for the lowest tested compressor stage). Therefore, the AHRI
1340-202X Draft and AHRI 1340-2023 include corrections in these cases
so that auxiliary heat demand is applied to meet building load in all
cases in which compressors are cut out.
3. Fan power applied in auxiliary heat-only mode: In appendix C of
the Term Sheet, the equations do not subtract the heat gain in the
indoor airstream from the indoor fan (i.e., ``fan heat'') from the
auxiliary heat demand. The AHRI 1340-202X Draft and AHRI 1340-2023
address this issue by subtracting fan heat from auxiliary heat demand.
Additionally, sections c and d of appendix C of the ACUAC and ACUHP
Working Group TP Term Sheet assume that the fan would be either cycling
between airflows when cycling between stages of compression or
operating at the lowest-measured indoor airflow for any cooling or
heating test when cycling on and off at the lowest stage of
compression; however, the indoor fan would likely be operating at the
airflow corresponding to the full-load heating test when operating in
auxiliary heat mode. The AHRI 1340-202X Draft and AHRI 1340-2023
address this by applying fan power from the full-load heating test for
auxiliary heat-only mode. However, DOE notes that because both fan heat
and auxiliary heat apply heat to the indoor airstream with the same
efficiency (i.e., COP of 1), the airflow assumed for auxiliary heat-
only mode does not impact results, as the fan heat resulting from an
increase in fan power reduces the auxiliary heat needed to meet the
building load by the same amount, resulting in no net change to
calculated IVHE.
4. Interpolation for variable-speed compressor systems: When
building load is between capacities of a unit tested with multiple
heating stages, section c of appendix C of the Term Sheet includes a
separate method for interpolating between stages for variable-speed
compressor systems (i.e., a method that interpolates capacity divided
by power) from the method for all other units (i.e., a method that
linearly interpolates power). As part of

[[Page 44011]]

development of the AHRI 1340-202X Draft, it was determined that there
were insufficient data to support a separate interpolation method for
variable-speed compressor systems, and, therefore, the AHRI 1340-202X
Draft and AHRI 1340-2023 apply the same linear interpolation method
based on power for all units. The linear interpolation method for
variable-speed compressor systems included in the AHRI 1340-202X Draft
is also maintained in AHRI 1340-2023.
5. Compressor operating levels for heating tests: Recommendation #9
of the Term Sheet includes details on the required and optional tests
based on configuration of the system (i.e., single-stage, two or more
stages, and variable-capacity). Required tests include a test at
``high'' operating level at 17 [deg]F and 47 [deg]F; optional tests
include tests at low and intermediate operating levels at 17 [deg]F and
47 [deg]F, as well as high and ``boost'' operating levels at 5 [deg]F.
For variable-capacity systems, the Term Sheet specifies that the high
speed and low speed at each temperature should be the normal maximum
and minimum for each ambient temperature. The AHRI 1340-202X Draft
includes additional explanation of which compressor speeds correspond
to the low, medium, high, and boost designations at each test
temperature. AHRI 1340-2023 maintains the explanations included in AHRI
1340-202X Draft and includes further explanation of the compressor
operating levels, as discussed in section III.E.8.b of this final rule.
In the August 2023 TP NOPR, DOE tentatively concluded that these
updated IVHE equations as described in the preceding paragraphs would
provide for a more accurate calculation of IVHE. 88 FR 56392, 56419
(August 17, 2023). Further, Recommendation #9 of the ACUAC and ACUHP
Working Group TP Term Sheet states that the equations in appendix C of
the Term Sheet are subject to quality control checking (``QC'') for
errors with the intent remaining the same as voted on. In the August
2023 TP NOPR, DOE tentatively concluded that the discussed deviations
in the AHRI 1340-202X Draft hold the same intent of the recommendations
set forth in the ACUAC and ACUHP Working Group TP Term Sheet.
Therefore, DOE proposed to adopt the provisions of AHRI 1340-202X Draft
for determining IVHE in appendix A1, including the updated equations
discussed in this section. 88 FR 56392, 56418-56419 (August 17, 2023).
AHRI 1340-2023 includes the largely the same provisions as AHRI
1340-202X Draft for determining IVHE. Any differences between the
provisions in AHRI 1340-202X Draft and AHRI 1340-2023 are discussed in
section III.E.8 of this final rule. Therefore, DOE has concluded that
that the updated IVHE equations in AHRI 1340-2023, as described in the
preceding paragraphs, would provide for a more accurate calculation of
IVHE than the equations in the ACUAC and ACUHP Working Group TP Term
Sheet, and that the discussed deviations hold the same intent as the
recommendations set forth in the ACUAC and ACUHP Working Group TP Term
Sheet. Therefore, DOE is adopting in appendix A1 the approach for
determining IVHE from AHRI 1340-2023.
DOE notes that appendix C of the ACUAC and ACUHP Working Group TP
Term Sheet includes a provision that ``additional provisions, still TBD
would apply for variable-speed compressors for which pairs of full-
speed or minimum-speed tests are not run at the same speed.'' (See
EERE-2022-BT-STD-0015-0065 at p. 14) The AHRI 1340-202X Draft does not
include any provisions allowing for determination of capacity for a bin
by interpolating between tests conducted at different compressor
operating levels. In the August 2023 TP NOPR, DOE tentatively concluded
that this approach is appropriate and that calculating IVHE with
results from multiple tests at each compressor operating level would
provide representative ratings for manufacturers that choose to include
performance at operating levels beyond the required high operating
level tests at 47 and 17 [deg]F in their representations of IVHE. 88 FR
56392, 56419 (August 17, 2023). AHRI 1340-2023 also includes no such
provisions allowing interpolation between tests conducted at different
compressor operating levels. Therefore, DOE maintains its tentative
conclusion from the August 2023 TP NOPR and is adopting the approach
for determining IVHE from AHRI 1340-2023 unchanged.
8. Heating Test Provisions Not Included in the AHRI 1340-202X Draft
a. General
As discussed in the August 2023 TP NOPR (88 FR 56392, 56418-56419
(August 17, 2023)) and section III.E.7.g of this final rule, the AHRI
1340-202X Draft includes conditions for heating tests and calculations
for the IVHE, IVHE<INF>C</INF>, and COP2 metrics that DOE proposed to
adopt in the August 2023 TP NOPR. AHRI 1340-2023 includes several
updates to the heating test provisions as compared to the AHRI 1340-
202X Draft. The following sections describe these updates and what DOE
is adopting in this final rule.
b. Definitions of Heating Operating Levels
Table 26 to AHRI 1340-202X Draft and section 6.3.5 of AHRI 1340-
202X Draft specify the heating operating levels to use and the
requirements for each, but do not make clear the parameters included in
defining an operating level. Section 3.2.31 of AHRI 1340-2023 includes
definitions for all heating operating levels, as well as a general
definition of ``operating level.'' Section 3.2.31.6 defines ``operating
level'' as being determined by the number of compressors operating, the
modulation level of each operating compressor, and the indoor fan
speed. The definition indicates that the modulation level of a single
compressor is determined by the speed, duty cycle, vapor injection
setting, and state of any other operating parameters that affect the
continuous capacity of the compressor at a single set of operating
conditions.
DOE is adopting these AHRI 1340-2023 operating level definitions in
the DOE test procedure for CUACs and CUHPs, because DOE has concluded
that they provide appropriate clarity on how to determine the operating
levels to be used for heating tests and are substantively consistent
with the AHRI 1340-202X Draft, which DOE proposed to adopt in the
August 2023 TP NOPR. The one exception is the definition for the
``boost2 heating operating level,'' which is discussed in section
III.E.8.c of this final rule.
c. Boost2 Heating Operating Level and COP25
The AHRI 1340-202X Draft includes low, medium, high, and boost
heating operating levels, with boost being the operating level with the
highest heating capacity. The boost operating level uses the maximum
compressor operating capacity that is allowed by the controls at 17
[deg]F, and the airflow that is allowed by the controls at 17 [deg]F
when operating at the chosen compressor operating capacity. AHRI 1340-
2023 includes all the same heating operating levels as the AHRI 1340-
202X Draft, plus a boost2 heating operating level. AHRI 1340-2023
defines the ``boost2 operating level'' as an operating level allowed by
the controls at 5 [deg]F outdoor dry-bulb temperature with a capacity
at 5 [deg]F outdoor dry-bulb temperature that is greater than the
capacity of the boost heating operating level at 5 [deg]F outdoor dry-
bulb temperature and less than or equal to the maximum capacity allowed
by the controls at 5 [deg]F outdoor dry-bulb temperature.

[[Page 44012]]

For units with a boost operating level, AHRI 1340-2023 specifies
representations of COP2<INF>5</INF> be based on the capacity and power
determined at the boost or boost2 heating operating level denoted as
the H5B or H5B2 tests in Table 23 to AHRI 1340-2023. However, AHRI
1340-2023 does not allow the H5B2 test to be used in the calculation of
IVHE or IVHE<INF>C</INF>. As discussed in section III.E.7.g of this
document, AHRI 1340-2023 does not include any provisions allowing for
determination of capacity for a bin by interpolating between tests
conducted at different compressor operating levels. Therefore,
inclusion of results from the boost2 operating level would require at
least two tests conducted at this operating level. Because there is no
other test specified at a different outdoor dry-bulb temperature
condition at this same boost2 operating level, AHRI 1340-2023 only
allows the H5B2 test to be used to determine the capacity at 5 [deg]F
outdoor dry-bulb temperature or COP2 at 5 [deg]F.
DOE has determined that including a boost2 heating operating level
allows for manufacturers to make performance representations that
adequately reflect boosted heating performance at lower temperatures.
DOE notes that Recommendation #9 of the ACUAC and ACUHP Working Group
TP Term Sheet includes the following: ``Manufacturers can make
representations of COP and capacity at any of the following
temperatures: 5 [deg]F, 17 [deg]F, and 47 [deg]F, in accordance with
the DOE test procedure, in addition to the IVHE metric that will be
required for standards.'' (See EERE-2022-BT-STD-0015-0065 at p. 6) As
mentioned in section III.E.4 of this final rule, DOE acknowledges that
in the future manufacturers will likely develop CUHPs that are designed
for operation in colder climates. This may include designing CUHPs that
are capable of providing boosted heating capacity at low temperatures.
DOE has determined that the inclusion of the boost2 heating operating
level and the H5B2 test in AHRI 1340-2023 is consistent with the intent
of Recommendation #9 of the Term Sheet. This will allow for
manufacturers designing systems with boosted heating capacity at 5
[deg]F that differs from the operating levels at higher outdoor
temperatures to make representations of capacity and performance at 5
[deg]F, and correspondingly provide commercial consumers interested in
low-temperature heating performance an additional standardized metric
to compare such performance across models. Further, DOE has concluded
that the inclusion of the boost2 heating operating level and the H5B2
test in AHRI 1340-2023 is generally consistent with the AHRI 1340-202X
Draft, in that it maintains the proposed allowance for optional
representations at 5 [deg]F, but adds additional options for
manufacturers to determine this optional representation at the
compressor speed most representative for a model. As discussed, testing
at the boost2 heating operating level is optional and would not be
required for determinations of IVHE. DOE is adopting the H5B2 test in
its amended test procedure at appendix A1, but with two additional
clarifying provisions not included in AHRI 1340-2023.
First, section 6.3.14.2 of AHRI 1340-2023 specifies that for
determining the COP2<INF>5</INF> of units with a boost operating level,
one must use the capacity and power determined for the H5B or H5B2
test, instead of the H5H test. These provisions indicate that optional
COP2<INF>5</INF> representations for such units are based on a higher
heating operating level but do not specify whether the H5B or H5B2 test
is to be used for a unit that has both a boost heating operating level
and a boost2 heating operating level. DOE has determined that
additional specificity is warranted as to which test is used to
determine optional COP2<INF>5</INF> representations--specifically, DOE
has concluded that it should be clarified to use the highest applicable
heating operating level to determine COP2<INF>5</INF>. Therefore, DOE
is adding the following clarification to section 5.3 of appendix A1:
For units without a boost heating operating level and without a boost 2
heating operating level, use capacity and power determined for the H5H
test. For units with a boost heating operating level and without a
boost 2 heating operating level, use capacity and power determined for
the H5B test. For units with a boost 2 heating operating level, use
capacity and power determined for the H5B2 test.
Second, section 3.2.31.1 of AHRI 1340-2023 defines the ``boost
heating operating level'' as the operating level that has the maximum
capacity allowed by the controls at 17 [deg]F outdoor dry-bulb
temperature, with a capacity at 17.0 [deg]F outdoor dry-bulb
temperature that is greater than the capacity of the high heating
operating level \22\ at 17 [deg]F. This means that there is no boost
heating operating level if the high heating operating level is the
heating operating level with the maximum capacity at 17 [deg]F. Section
3.2.31.2 of AHRI 1340-2023 defines the ``boost2 heating operating
level'' as an operating level allowed by the controls at 5 [deg]F
outdoor dry bulb-temperature with a capacity at 5 [deg]F outdoor dry
bulb-temperature that is greater than the capacity of the boost heating
operating level at 5 [deg]F and less than or equal to the maximum
capacity allowed by the controls at 5 [deg]F outdoor dry bulb-
temperature.
---------------------------------------------------------------------------

\22\ Section 3.2.31.3 of AHRI 1340-2023 defines ``high heating
operating level'' as the operating level with the maximum capacity
that is allowed by the controls at 47.0 [deg]F outdoor dry-bulb
temperature.
---------------------------------------------------------------------------

Because the definition of the ``boost2 heating operating level''
relies on the capacity of the boost operating level, the definition
implies that a model must have an operating level that meets the
definition for the boost heating operating level in order for it to
also have a boost2 heating operating level. This implication means that
AHRI 1340-2023 would not allow the H5B2 test to be conducted for a
model which has no boost heating operating level at 17 [deg]F, even if
that model has an operating level with a capacity at 5 [deg]F that is
greater than the capacity of the high heating operating level at 5
[deg]F. DOE has determined that such a scenario is possible and should
be accounted for in the definition for the ``boost2 heating operating
level'' and the requirements for the H5B2 test.
As such, DOE is not adopting the definition for the ``boost2
heating operating level'' in section 3.2.31.2 of AHRI 1340-2023.
Instead, DOE is adopting the following definition for the ``boost2
heating operating level'' in section 5.1 of appendix A1, which
addresses the aforementioned scenario of a model with a boosted
operating level at 17 [deg]F but not 5 [deg]F: ``An operating level
allowed by the controls at 5.0 [deg]F outdoor dry-bulb temperature with
a capacity at 5.0 [deg]F outdoor dry-bulb temperature that is less than
or equal to the maximum capacity allowed by the controls at 5.0 [deg]F
outdoor dry-bulb temperature, and greater than the capacity of: (a) the
Boost Heating Operating Level at 5.0 [deg]F outdoor dry-bulb
temperature, if there is an operating level that meets the definition
for Boost Heating Operating Level specified in section 3.2.31.1 of AHRI
1340-2023; or (b) the High Heating Operating Level at 5.0 [deg]F
outdoor dry-bulb temperature, if there is not an operating level that
meets the definition for Boost Heating Operating Level'' specified in
section 3.2.31.1 of AHRI 1340-2023.
Correspondingly, DOE is also specifying in section 5.2 of appendix
A1 updated requirements for the H5B2 test of AHRI 1340-2023 that are to
be used in case a model has no heating operating level that meets the
definition of ``boost

[[Page 44013]]

heating operating level'' in section 3.2.31.1 of AHRI 1340-2023.
Section 6.3.6 of AHRI 1340-2023 specifies to run the H5B2 test in Table
23 to AHRI 1340-2023 with an operating level allowed by the controls at
5.0 [deg]F outdoor dry-bulb temperature that has a capacity at 5.0
[deg]F outdoor dry-bulb temperature that is greater than the capacity
of the Boost Heating Operating Level at 5.0 [deg]F. In section 5.2 of
appendix A1, DOE is instead adopting a revised version of that
provision that replaces the comparison to capacity of the Boost Heating
Operating Level at 5.0 [deg]F with a comparison to capacity of the High
Heating Operating Level at 5.0 [deg]F.
As noted previously, DOE has concluded that the inclusion of the
boost2 heating operating level and the H5B2 test in AHRI 1340-2023 is
generally consistent with the AHRI 1340-202X Draft. Similarly, DOE has
concluded that the provisions discussed in this section (i.e., to allow
use of the boost2 heating operating level for determining optional
representations at 5 [deg]F for a model which has no boost heating
operating level at 17 [deg]F, and to clarify which test should be used
for optional COP2<INF>5</INF> representations depending on which
heating operating levels apply at 5 [deg]F) maintain the proposed
allowance for optional representations at 5 [deg]F, but add options and
clarity for manufacturers to consistently determine this optional
representation at the compressor speed most representative for a model.
DOE understands that the AHRI Commercial Unitary STC also plans to
address the aforementioned clarifications regarding the instructions
for which test to use for optional representation of COP2<INF>5</INF>
and the definition of ``boost2 heating operating level'' that were
published in AHRI 1340-2023. DOE expects that AHRI will consider
including such clarifications in a future version of AHRI 1340,
consistent with the clarifications adopted in this final rule.
d. Extrapolation of Boost Heating Operating Level to 21 [deg]F
As discussed in section III.E.7.g of this final rule, AHRI 1340-
202X Draft requires interpolation of capacity and power between tests
of the same operating level at different outdoor air temperatures when
calculating values for the temperature bins used in IVHE and
IVHE<INF>C</INF>. Extrapolation of capacity and power are not allowed
in AHRI 1340-202X Draft.
Sections 6.3.8 and 6.3.9 of AHRI 1340-2023 allow for capacity and
power from boost heating operating level tests conducted at 5 [deg]F
and 17 [deg]F to be used to extrapolate boost heating operating level
performance up to 21 [deg]F. This allows manufacturers to take
advantage of the boost heating operating level for calculations of the
IVHE and IVHE<INF>C</INF> bins with outdoor air dry-bulb temperatures
between 17 [deg]F and 22 [deg]F.\23\
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\23\ Table 22 of AHRI 1340-2023 specifies: (1) for the IVHE
metric, bin temperatures of 21 [deg]F and 18.1 [deg]F for bin
numbers 8 and 9; and (2) for the IVHE<INF>C</INF> metric, a bin
temperature of 20.0 [deg]F for bin number 5.
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DOE has determined that these provisions are appropriate and will
allow for more representative accounting of performance for bin
temperatures between 17 [deg]F and 22 [deg]F, which are conditions at
which models would likely operate at boost heating operating level, as
necessary, to meet the building load, if the model operated as such for
tests at 17 [deg]F (i.e., it would be unlikely that a model would have
a boost operating level that engages at 17 [deg]F but not at 22
[deg]F). Further, DOE has concluded that these provisions are generally
consistent with the AHRI 1340-202X Draft in that the provisions
maintain the same compressor operating levels for determining IVHE, but
the upper temperature limit to which boost heating performance can be
applied is being slightly extended (by 5 [deg]F, from 17 [deg]F to 22
[deg]F) to more representatively account for performance between 17
[deg]F to 22 [deg]F. Therefore, DOE is adopting the provisions allowing
extrapolation of boost heating operating level performance in sections
6.3.8 and 6.3.9 of AHRI 1340-2023.
e. Operating Levels Used for Optional COP217 Representations
As previously mentioned in section III.E.8.c of this document, AHRI
1340-2023 specifies that for units with a boost operating level,
representations of COP2<INF>5</INF> is to be based on the capacity and
power determined at the boost or boost 2 heating operating level
denoted as the H5B or H5B2 test, instead of the H5H test. However,
while AHRI 1340-2023 includes a boost operating level test at 17 [deg]F
(the H17B test), section 6.3.14.2 of AHRI 1340-2023 requires that
COP2<INF>17</INF> be determined using the capacity and power determined
for the H17H test and does not allow for the COP2<INF>17</INF> to be
determined using the capacity and power determined for the H17B test if
conducted. Similar to its conclusions regarding the use of the H5B or
H5B2 test for determining COP2<INF>5</INF>, DOE has determined it would
be appropriate to require the H17B test to be used for representations
of COP2<INF>17</INF> if conducted because representations of efficiency
at the maximum capacity for a given test condition are common and
useful for consumers and utilities. Therefore, DOE is also specifying
in this final rule that the H17B test, if conducted, be used for
determining COP2<INF>17</INF>, in order to allow manufacturers to make
optional representations of capacity and performance at that operating
level for models that are capable of boost operation. DOE understands
that the AHRI Commercial Unitary STC also plans to specify that the
H17B test is to be used for determining COP2<INF>17</INF> if this test
is conducted. DOE expects that AHRI will consider including prescribing
the use of the H17B test in appropriate cases for representations of
COP2<INF>17</INF>, consistent with this final rule, in a future version
of AHRI 1340.
9. Test Procedure Revisions Recommended for a Future Rulemaking
NYSERDA generally supported the proposed IVEC and IVHE metrics but
commented that the heating test provisions proposed do not adequately
account for fan energy consumed during auxiliary heating mode.
(NYSERDA, No. 13 at pp. 2-3) NYSERDA recommended DOE consider the
inclusion of an additional energy consumption term in the denominator
of the IVHE calculation to account for supply fan energy use for
commercial warm air furnaces, which NYSERDA stated would support
recommendation #11 of the ACUAC and ACUHP Working Group TP Term Sheet.
NYSERDA recommended addressing the fan energy consumption issue at the
next appropriate juncture. (Id.)
NEEA recommended DOE consider the following items the next time the
CUAC/HP test procedure is reviewed: (1) impacts of outside air damper
leakage; (2) energy saving potential from energy recovery ventilators
(``ERV''); (3) benefits of variable-capacity or variable-speed
compressors, and (4) a controls verification procedure (``CVP'').
(NEEA, No. 16 at p. 4)
At this time DOE has concluded that it does not have sufficient
information or data to justify adopting deviations from the IVEC and
IVHE metrics negotiated by the Working Group and included in the
industry consensus test procedure AHRI 1340-2023. Therefore, DOE is
adopting the IVEC and IVHE metrics as specified in AHRI 1340-2023.
Regarding NYSERDA's comments on fan energy consumption in the IVHE
metric, DOE notes that IVHE is the heating metric for CUHPs and assumes
electric resistance supplementary heat for all models. Dual fuel CUHPs
(i.e., CUHPs with gas furnace supplementary heat) will still have IVHE
ratings that reflect electric resistance supplementary heat. The IVHE
metric accounts for

[[Page 44014]]

supply fan energy during all hours with a heating load, regardless of
whether the IVHE calculations assume the heating load is met by
mechanical heating only, electric resistance heating only, or both, as
described in section III.D.2 of this document. Therefore, DOE has
concluded that no fan energy use for CUHPs is unaccounted for in the
IVHE metric. DOE recognizes NEEA's suggested topics for consideration
in a future test procedure rulemaking, but consistent with NEEA's
comment, DOE is not addressing these topics in this final rule.

F. Configuration of Unit Under Test

1. Summary
CUACs and CUHPs are sold with a wide variety of components,
including many that can optionally be installed on or within the unit
both at the factory and in the field. The following sections address
the required configuration of units under test. In all cases, these
components are distributed in commerce with the CUAC and CUHP but can
be packaged or shipped in different ways from the point of manufacture
for ease of transportation. Each optional component may or may not
affect a model's measured efficiency when tested to the DOE test
procedure adopted in this final rule. For certain components not
directly addressed in the DOE test procedure, the August 2023 TP NOPR
proposed more specific instructions on how each component should be
handled for the purposes of making representations in 10 CFR part 429.
88 FR 56392, 56430-56433 (August 17, 2023). Specifically, the proposed
instructions were intended to provide manufacturers with clarity on how
components should be treated and how to group individual models with
and without optional components for the purposes of representations to
reduce burden. Id. DOE proposed these provisions in 10 CFR part 429 to
allow for testing of certain individual models that can be used as a
proxy to represent the performance of equipment with multiple
combinations of components. Id.
In the August 2023 TP NOPR, DOE proposed to handle CUAC and CUHP
components in two distinct ways to help manufacturers better understand
their options for developing representations for their differing
product offerings. Id. First, DOE proposed that the treatment of
certain components be specified by the test procedure, such that their
impact on measured efficiency is limited. Id. For example, a fresh air
damper must be set in the closed position and sealed during testing,
resulting in a measured efficiency that would be similar or identical
to the measured efficiency for a unit without a fresh air damper.
Second, DOE proposed provisions expressly allowing certain models to be
grouped together for the purposes of making representations and
allowing the performance of a model without certain optional components
to be used as a proxy for models with any combinations of the specified
components, even if such components would impact the measured
efficiency of a model. Id. A steam/hydronic coil is an example of such
a component. The efficiency representation for a model with a steam/
hydronic coil is based on the measured performance of the CUAC and CUHP
as tested without the component installed because the steam/hydronic
coil is not easily removed from the CUAC and CUHP for testing.\24\ Id.
---------------------------------------------------------------------------

\24\ Note that in certain cases, as explained further in section
III.F.3.b of this document, the representation may have to be based
on an individual model with a steam/hydronic coil.
---------------------------------------------------------------------------

In this final rule, DOE is adopting provisions regarding
configuration of unit under test largely similar to those proposed, but
with several differences from the proposed provisions, as discussed in
the following sections. Specifically, the following sections provide a
background for the proposed provisions, describe the proposed
provisions, describe relevant updates in AHRI 1340-2023 that were not
included in the AHRI 1340-202X Draft, summarize and respond to the
comments that DOE received in response to the August 2023 TP NOPR, and
discuss the provisions that DOE is adopting in this final rule.
2. Background
In 2013, ASRAC formed the Commercial HVAC Working Group to engage
in a negotiated rulemaking effort regarding the certification of
certain commercial heating, ventilating, and air conditioning
equipment, including CUACs and CUHPs. (See 78 FR 15653 (March 12,
2013)) This Commercial HVAC Working Group submitted a term sheet
(Commercial HVAC Term Sheet) providing the Commercial HVAC Working
Group's recommendations. (See EERE-2013-BT-NOC-0023-0052 \25\) The
Commercial HVAC Working Group recommended that DOE issue guidance under
current regulations on how to test certain equipment features when
included in a basic model, until such time as the testing of such
features can be addressed through a test procedure rulemaking. The
Commercial HVAC Term Sheet listed the subject features under the
heading ``Equipment Features Requiring Test Procedure Action.'' (Id at
pp. 3-9) The Commercial HVAC Working Group also recommended that DOE
issue an enforcement policy stating that DOE would exclude certain
equipment with specified features from DOE testing, but only when the
manufacturer offers for sale at all times a model that is identical in
all other features; otherwise, the model with that feature would be
eligible for DOE testing. These features were listed under the heading
``Equipment Features Subject to Enforcement Policy.'' (Id. at pp. 9-15)
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\25\ Available at <a href="http://www.regulations.gov/document/EERE-2013-BT-NOC-0023-0052">www.regulations.gov/document/EERE-2013-BT-NOC-0023-0052</a>.
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On January 30, 2015, DOE issued a Commercial HVAC Enforcement
Policy addressing the treatment of specific features during DOE testing
of commercial HVAC equipment. (See <a href="http://www.energy.gov/gc/downloads/commercial-equipment-testing-enforcement-policies">www.energy.gov/gc/downloads/commercial-equipment-testing-enforcement-policies</a>) The Commercial HVAC
Enforcement Policy stat

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