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

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.

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

www.regulations.gov

under docket number EERE-2023-BT-TP-0014. All documents in the docket are listed in the

www.regulations.gov

index. However, not all documents listed in the index may be publicly available, such as those containing information that is exempt from public disclosure.

A link to the docket web page can be found at

www.regulations.gov/docket/EERE-2023-BT-TP-0014.

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:

ApplianceStandardsQuestions@ee.doe.gov.

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:

ApplianceStandardsQuestions@ee.doe.gov.

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:

Eric.Stas@hq.doe.gov.

For further information on how to review the docket, contact the Appliance and Equipment Standards Program staff at (202) 287-1445 or by email:

ApplianceStandardsQuestions@ee.doe.gov.

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:

www.ahrinet.org/standards/search-standards.

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:

www.ashrae.org.

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

5

d. Extrapolation of Boost Heating Operating Level to 21 °F

e. Operating Levels Used for Optional COP2

17

Representations

9. Test Procedure Revisions Recommended for a Future Rulemaking

F. Configuration of Unit Under Test

1. Summary

2. Background

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.

ER20MY24.126

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.

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(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, § 431.96, table 1. The following sections discuss DOE's

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.

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.

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.

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.

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

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.

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.

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.

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

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.

ER20MY24.127

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

www.regulations.gov

) 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

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

www.ahrinet.org/system/files/2023-10/ULE_OM.pdf.

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

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

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

C

”). 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

C

). 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

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 °F capacity and performance for systems with more than two operating levels;

4. Allowance for the test conducted at 5 °F and 17 °F at the boost heating operating level to be used for IVHE bins ranging from 5 °F to 21 °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

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 °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

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.

ER20my24.128

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

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.

ER20my24.129

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 °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 °F and 17 °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 °F and 17 °F temperature conditions, as well as test conditions for optional testing at a 5 °F full-load condition. Finally, the recommendation includes test requirements for optional boost tests at the 17 °F and 5 °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 °F and 47 °F. Appendix C also includes the following instructions for bins with temperatures less than 17 °F: (1) interpolation instructions to be used if the optional

5 °F test is conducted, and (2) extrapolation instructions utilizing the 47 °F and 17 °F test data to be used if the 5 °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 °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

(“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

2

O for double-duct systems. When testing with 0.50 in. H

2

O outdoor air ESP, ratings are designated with the subscript “DD” (

e.g.,

EER

DD

, COP

DD

, and IEER

DD

) 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

DD

, COP

DD

, and/or IEER

DD

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

2

O outdoor air ESP requirement for determining IVEC and IVHE for double-

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

DD

, COP

DD

, and/or IEER

DD

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

DD

, COP

DD

, and/or IEER

DD

(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-

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

2

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

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 °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.

ER20my24.130

ER20my24.131

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.

ER20my24.132

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

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 °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 °F, and less than 1 percent of heating hours are in a load bin with a temperature colder than 17 °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

C

. Specifically, IVHE

C

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

C

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

C

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

C

, 56 percent of heating hours are in a load bin with a temperature colder than 32 °F, and 12 percent of heating hours are in a load bin with a temperature colder than 17 °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

C

has colder bin temperatures than IVHE), the AHRI 1340-202X Draft also specifies separate defrost degradation coefficients for calculating IVHE

C

. In the August 2023 TP NOPR, DOE proposed to adopt provisions for determining the IVHE

C

metric in appendix A1 via reference to the AHRI 1340-202X Draft and to allow for optional representations of IVHE

C

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

C

. (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

C

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

C

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

C

metric in appendix A1 via reference to AHRI 1340-2023 and allowing for optional representations of IVHE

C

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

C

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 °F and 17 °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 °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

47

, COP2

17

, and COP2

5

, and specified the test conditions required for these optional representations.

Id.

DOE did not receive any comments regarding

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

2

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

2

O when testing

coil-only units, as compared to the maximum pressure drop of 0.3 in. H

2

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

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 She

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