Energy Conservation Program: Test Procedure for VRF Multi-Split Systems

Federal RegisterOct 20, 2022

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2021-BT-TP-0019]

RIN 1904-AE43

Energy Conservation Program: Test Procedure for VRF Multi-Split Systems

AGENCY:

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

ACTION:

Final rule.

SUMMARY:

This final rule amends the test procedure for variable refrigerant flow (“VRF”) multi-split air conditioners and heat pumps (“VRF multi-split systems”) to incorporate by reference the latest version of the applicable industry test standard. This final rule also adopts the integrated energy efficiency ratio metric in its test procedures for VRF multi-split systems. Additionally, this final rule adopts provisions in the updated industry test procedure relevant to certification and enforcement, including a controls verification procedure.

DATES:

The effective date of this rule is November 21, 2022. The final rule changes will be mandatory for VRF multi-split systems equipment testing October 16, 2023. The incorporation by reference of certain publications listed in this rule is approved by the Director of the Federal Register on November 21, 2022. The incorporation by reference of certain other publications listed in this rule was approved by the Director of the Federal Register as of July 30, 2015, and July 16, 2012.

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.

All documents in the docket are listed in the

www.regulations.gov

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

A link to the docket web page can be found at

www.regulations.gov/docket/EERE-2021-BT-TP-0019.

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:

Ms. Catherine Rivest, U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies Office, EE-5B, 1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: (202) 586-7335. Email:

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) 586-5827. Email:

Eric.Stas@hq.doe.gov.

SUPPLEMENTARY INFORMATION:

DOE incorporates by reference the following industry standards as follows:

AHRI Standard 1230 (I-P), “2021 Standard for Performance Rating of Variable Refrigerant Flow (VRF) Multi-Split Air-Conditioning and Heat Pump Equipment;” copyright 2021 (“AHRI 1230-2021”)—into parts 429 and 431.

ANSI/AHRI 1230-2010, 2010 Standard for Performance Rating of Variable Refrigerant Flow (VRF) Multi-Split Air-Conditioning and Heat Pump Equipment,” approved August 2, 2010 and updated by addendum 1 in March 2011 (“ANSI/AHRI 1230-2010”)—into part 431.

Copies of AHRI 1230-2021 and ANSI/AHRI 1230-2010 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/search-standards.aspx.

ANSIASHRAE 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”)—into part 431.

ASHRAE Errata Sheet for ANSI/ASHRAE Standard 37-2009—Methods of Testing for Rating Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment, ASHRAE approved March 27, 2019, (“ASHRAE Errata Sheet for ANSI/ASHRAE Standard 37-2009”).

Copies of ANSI/ASHRAE Standard 37-2009 and ASHRAE Errata Sheet for ANSI/ASHRAE Standard 37-2009 are available from 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. Authority and Background

A. Authority

B. Background

II. Synopsis of the Final Rule

III. Discussion

A. Scope of Applicability

B. Organization of the VRF Multi-Split System Test Procedure

C. Industry Standards

1. Updates to AHRI 1230

2. ASHRAE 37

D. Metrics

1. IEER

2. Test Conditions Used for Efficiency Metrics

E. Controls Verification Procedure

1. Background

2. When the CVP Is Conducted

3. Critical Parameter Definition

4. Validation of Certified Critical Parameters

a. Validation Time Period

b. Validation Criteria

5. Determination of Alternate Critical Parameters

F. Allowable Critical Parameter Adjustment

1. Adjustment of Certified Critical Parameter Values

2. Adjustment of Alternate Critical Parameter Values

G. Certification, Compliance, and Enforcement

1. Determination of Represented Values

a. Introduction

b. NOPR Proposals and Comments

c. Final Rule Approach

2. Certification Reporting Requirements

a. Certification Requirements

b. Supplemental Testing Instructions

3. Models Required for AEDM Validation

4. Manufacturer Involvement

a. Role of Manufacturer Representative

b. Control Tool

5. Break-In Period

6. Certified Critical Parameter Operational Settings

7. Enforcement Sampling Plan

8. Certified vs. Tested Performance

H. Effective and Compliance Dates

I. Test Procedure Costs

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Orders 12866 and 13563

B. Review Under the Regulatory Flexibility Act

C. Review Under the Paperwork Reduction Act of 1995

D. Review Under the National Environmental Policy Act of 1969

E. Review Under Executive Order 13132

F. Review Under Executive Order 12988

G. Review Under the Unfunded Mandates Reform Act of 1995

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

I. Review Under Executive Order 12630

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

K. Review Under Executive Order 13211

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

M. Congressional Notification

N. Description of Materials Incorporated by Reference

V. Approval of the Office of the Secretary

I. Authority and Background

Commercial package air conditioning and heating equipment is included in the list of “covered equipment” for which the U.S. Department of Energy (“DOE”) is authorized to establish and amend energy conservation standards and test procedures. (42 U.S.C. 6311(1)(B)-(D)) Commercial package air conditioning and heating equipment includes variable refrigerant flow multi-split air conditioners and heat pumps (“VRF multi-split systems”). DOE's energy conservation standards and test procedure for VRF multi-split systems are currently prescribed at 10 CFR 431.97 and 10 CFR 431.96, respectively. The following sections discuss DOE's authority to establish test procedures for VRF multi-split systems and relevant background information regarding DOE's consideration of test procedures for this equipment.

A. Authority

The Energy Policy and Conservation Act, as amended (“EPCA”),

Public Law 94-163 (42 U.S.C. 6291-6317, as codified), among other things, authorizes DOE to regulate the energy efficiency of a number of consumer products and certain industrial equipment. Title III, Part C

of EPCA, added by Public Law 95-619, Title IV, section 441(a), established the Energy Conservation Program for Certain Industrial Equipment, which sets forth a variety of provisions designed to improve energy efficiency. This equipment includes small, large, and very large commercial package air conditioning and heating equipment, which includes VRF multi-split systems, the subject of this document. (42 U.S.C. 6311(1)(B)-(D))

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.

For editorial reasons, upon codification in the U.S. Code, Part C was redesignated as 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 for particular State laws or regulations, in accordance with the procedures and other provisions of EPCA. (42 U.S.C. 6316(b)(2)(D))

Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures DOE must follow when prescribing or amending test procedures for covered equipment. EPCA requires that any test procedures prescribed or amended under this section must be reasonably designed to produce test results which reflect energy efficiency, energy use, or estimated annual operating cost of a given type of covered equipment during a representative average use cycle and requires that test procedures not be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))

With respect to VRF multi-split systems, EPCA requires that the test procedures shall be those generally accepted industry testing procedures or rating procedures developed or recognized by AHRI or the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (“ASHRAE”), as referenced in ASHRAE/IES 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 amend its test procedure to be consistent with the amended industry test procedure unless DOE determines, by a rule published in the

Federal Register

and supported by clear and convincing evidence, that the amended test procedure would be unduly burdensome to conduct or would not produce test results that reflect the energy efficiency, energy use, and estimated operating costs of that equipment during a representative average use cycle. (42 U.S.C. 6314(a)(4)(B))

EPCA also requires that, at least once every 7 years, DOE evaluate test procedures for each type of covered equipment, including VRF multi-split systems, 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))

In addition, if the Secretary determines that a test procedure amendment is warranted, DOE 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 comments 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 amending the test procedure for VRF multi-split systems in satisfaction of its statutory obligations under EPCA.

B. Background

DOE's existing test procedure for VRF multi-split systems appears at 10 CFR 431.96, “Uniform test method for the measurement of energy efficiency of commercial air conditioners and heat pumps.” The Federal test procedure for VRF multi-split systems was last amended in a final rule for standards and test procedures for certain commercial heating, air conditioning, and water heating equipment published in the

Federal Register

on May 16, 2012 (“May 2012 Final Rule”). 77 FR 28928. With regard to VRF multi-split systems, the May 2012 Final Rule adopted the test procedure ANSI/AHRI 1230-2010, “

2010 Standard for Performance Rating of Variable Refrigerant Flow (VRF) Multi-Split Air-Conditioning and Heat Pump Equipment,”

approved August 2, 2010 and updated by Addendum 1 in March 2011 (“ANSI/AHRI 1230-2010”). 77 FR 28928, 28945-28946 (May 16, 2012);

see

10 CFR 431.96, Table 1. Specifically, the DOE test procedure for VRF multi-split systems was modified to reference ANSI/AHRI 1230-2010 with Addendum 1 but omitting sections 5.1.2 and 6.6. 77 FR 28928, 28990-28991 (May 16, 2012). The May 2012 Final Rule also adopted additional requirements, listed in 10 CFR 431.96(c) through (f), for measuring the energy efficiency ratio (“EER”) and coefficient of performance (“COP”) for air-cooled VRF multi-split systems with a cooling

capacity between 65,000 Btu/h and 760,000 Btu/h and water-source VRF multi-split systems with a cooling capacity less than 760,000 Btu/h.

Id.

These additional requirements specify provisions for equipment set-up and provide for limited involvement of manufacturer representatives during testing. 77 FR 28928, 28991 (May 16, 2012).

In 2016,

ASHRAE Standard 90.1 was updated, but the 2016 update did not make changes to the test procedure references in ASHRAE Standard 90.1-2013 for VRF multi-split systems. On July 25, 2017, DOE published in the

Federal Register

a request for information (“RFI”) (“July 2017 ASHRAE TP RFI”) to collect information and data to consider amendments to DOE's test procedures for commercial package air conditioning and heating equipment with the test procedure updates included in ASHRAE Standard 90.1-2016. 82 FR 34427. As part of the July 2017 ASHRAE TP RFI, DOE requested comment on the VRF multi-split systems test procedure, under the 7-year-lookback review requirement. 82 FR 34427, 34429 (July 25, 2017). DOE identified several issues that might have warranted modifications to the applicable VRF multi-split systems test procedure, in particular concerning incorporation by reference of the most recent version of the relevant industry standard(s); efficiency metrics and calculations; and clarification of test methods. 82 FR 34427, 34427 (July 25, 2017).

No publication date is printed on ASHRAE Standard 90.1-2016, but ASHRAE issued a press release on October 26, 2016, which is available at

www.ashrae.org/news/2016/ashrae-ies-publish-2016-energy-efficiency-standard

(Last accessed April 30, 2021).

In September 2017, AHRI published an update to ANSI/AHRI 1230-2010,

i.e.,

ANSI/AHRI 1230-2014 with Addendum 1 (although published in 2017, the update uses a 2014 designation).

On April 11, 2018, DOE published in the

Federal Register

a notice of its intent to establish a negotiated rulemaking working group (“Working Group”) under the Appliance Standards and Rulemaking Federal Advisory Committee (“ASRAC”), in accordance with the Federal Advisory Committee Act

and the Negotiated Rulemaking Act,

to negotiate the proposed test procedure and amended energy conservation standards for VRF multi-split systems. 83 FR 15514. The purpose of the Working Group was to discuss and, if possible, reach consensus on a proposed rule regarding the test procedure and energy conservation standards for VRF multi-split systems, as authorized by EPCA.

Id.

at 83 FR 15514.

5 U.S.C. App. 2, Public Law 92-463.

5 U.S.C. 561-570, Public Law 104-320.

The Working Group comprised 21 voting members including manufacturers, energy efficiency advocates, utilities, and trade organizations.

On October 1, 2019, the Working Group reached consensus on a term sheet (“VRF TP Term Sheet”; Docket No. EERE-2018-BT-STD-0003-0044) that includes the following recommendations, which highlight the most substantial changes:

A complete list of the ASRAC VRF Working Group members is available at:

www.energy.gov/eere/buildings/appliance-standards-and-rulemaking-federal-advisory-committee#Variable%20Refrigerant%20Flow%20Multi-Split%20Air%20Conditioners%20and%20Heat%20Pumps%20Working%20Group.

(1) VRF multi-split systems should be rated with the Integrated Energy Efficiency Ratio (“IEER”) metric to allow consumers to make consistent comparisons with rooftop air conditioner ratings.

(2) The amended test procedure should not be required until the compliance date of amended energy conservation standards.

(3) The Federal test procedure for VRF multi-split systems should be consistent with the September 20, 2019 draft version of AHRI 1230, with additional amendments to be implemented after the conclusion of ASRAC negotiations.

(

Id.

at pp. 1-3)

On May 18, 2021, AHRI published an updated industry test standard for VRF multi-split systems AHRI Standard 1230 (I-P),

“2021 Standard for Performance Rating of Variable Refrigerant Flow (VRF) Multi-Split Air-Conditioning and Heat Pump Equipment”

(“AHRI 1230-2021”). AHRI 1230-2021 references ANSI/ASHRAE Standard 37-2009, “

Methods of Testing for Rating Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment”

(“ANSI/ASHRAE 37-2009”), as corrected by the Errata Sheet issued March 27, 2019, for additional test set-up and methodology specifications.

These changes, along with comments received in response to the July 2017 ASHRAE TP RFI, were addressed in a test procedure NOPR for VRF multi-split systems published in the

Federal Register

on December 10, 2021 (“December 2021 VRF TP NOPR”). 86 FR 70644. In that NOPR, DOE proposed to incorporate by reference AHRI 1230-2021 and ANSI/ASHRAE 37-2009, as corrected by the Errata Sheet issued March 27, 2019) and establish provisions for determining IEER for VRF multi-split systems.

Id.

DOE also proposed to update its certification, compliance, and enforcement (“CCE”) provisions for VRF multi-split systems to provide information that is necessary for testing VRF multi-split systems consistent with the updated industry test procedure AHRI 1230-2021. DOE held a public meeting related to this NOPR on January 20, 2022 (hereafter, the “NOPR public meeting”).

DOE received comments in response to the December 2021 VRF TP NOPR from the interested parties listed in Table I.1.

Table I-1—List of Commenters With Written Submissions in Response to the December 2021 VRF TP NOPR

Commenter(s)

Reference in

this final rule

Docket entry No.

Commenter type

Air-Conditioning, Heating, & Refrigeration Institute

AHRI

Trade Association.

Appliance Standards Awareness Project, American Council for an Energy-Efficient Economy, and Natural Resources Defense Council

Joint Advocates

Efficiency Advocacy Organization.

California Energy Commission

CEC

State Official/Agency.

California Investor-Owned Utilities

CA IOUs

Utilities.

Carrier Global Corporation

Carrier

Manufacturer.

Daikin North America LLC

Daikin

Manufacturer.

Lennox International

Lennox

Manufacturer.

Northwest Energy Efficiency Analysis

NEEA

Efficiency Advocacy Organization.

New York State Energy Research and Development Authority

NYSERDA

State Official/Agency.

A parenthetical reference at the end of a comment quotation or paraphrase provides the location of the item in the public record.

To the extent that interested parties have provided written comments that are substantively consistent with any oral comments provided during the NOPR public meeting, DOE cites the written comments throughout this final rule. DOE did not identify any oral comments provided during the webinar that are not substantively addressed by written comments.

The parenthetical reference provides a reference for information located in the docket of DOE's rulemaking to develop test procedures for VRF multi-split systems. (Docket No. EERE-2021-BT-TP-0019, which is maintained at

www.regulations.gov

). The references are arranged as follows: (commenter name, comment docket ID number, page of that document).

On March 1, 2022, DOE published in the

Federal Register

an energy conservation standards NOPR (“March 2022 VRF ECS NOPR”) that proposed amended energy conservation standards for VRF multi-split systems that rely on the new IEER cooling metric and are equivalent to the levels specified in ASHRAE Standard 90.1-2019. 87 FR 11335.

II. Synopsis of the Final Rule

In this final rule, DOE is amending 10 CFR 431.96, “Uniform test method for the measurement of energy efficiency of commercial air conditioners and heat pumps,” to revise the relevant references to the most recent version of the industry test procedure as follows: (1) incorporating by reference AHRI 1230-2021 and ANSI/ASHRAE 37-2009, as corrected by the Errata Sheet issued March 27, 2019; and (2) establishing provisions for determining IEER for VRF multi-split systems. DOE is also adding new appendices D and D1 to subpart F of part 431, both titled “Uniform test method for measuring the energy consumption of variable refrigerant flow multi-split air conditioners and heat pumps (other than air-cooled with rated cooling capacity less than 65,000 Btu/h),” (“appendix D” and “appendix D1,” respectively). The current DOE test procedure for VRF multi-split systems is relocated from 10 CFR 431.96 to 10 CFR part 431, subpart F, appendix D without change, and the new test procedure adopting AHRI 1230-2021 is established in appendix D1 for determining IEER. Compliance with appendix D1 is not required until such time as compliance is required with amended energy conservation standards for VRF multi-split systems that rely on IEER, should DOE adopt such standards.

In this final rule, DOE is also updating its certification, compliance, and enforcement (“CCE”) provisions for VRF multi-split systems, to require reporting of information that is necessary for testing VRF multi-split systems consistent with the updated industry test procedure AHRI 1230-2021. Most significantly, these changes include the incorporation of the controls verification procedure (“CVP”) from AHRI 1230-2021 into DOE's product-specific enforcement provisions at 10 CFR 429.134, as well as accompanying certification requirements at 10 CFR 429.43. Additionally, DOE is specifying tested combinations to align with AHRI 1230-2021, clarifying the role of manufacturer involvement during testing, and specifying how to determine represented values for systems using different indoor unit combinations DOE is not reducing the enforcement testing sample size from four units to two units, as was proposed in the December 2021 VRF TP NOPR. Figure 1 presents a process diagram for DOE's certification, compliance, and enforcement regulations for VRF multi-split systems, as described in this final rule.

BILLING CODE 6450-01-P

ER20OC22.000

BILLING CODE 6450-01-C

The adopted amendments are summarized in Table II.1 and are compared to the test procedure provisions in place prior to these latest amendments, as well as the reason for each adopted change.

Table II-1—Summary of Changes in the Amended Test Procedure

DOE test procedure prior to

amendment

Amended test procedure

Attribution

Incorporates by reference ANSI/AHRI 1230-2010

Incorporates by reference in a new Appendix D1 AHRI 1230-2021 and ANSI/ASHRAE 37-2009 as corrected by the Errata Sheet issued March 27, 2019

Updates to the applicable industry test procedures.

Includes provisions for determining EER

Includes provisions for determining both EER and IEER

Updates to the applicable industry test procedures.

Does not include VRF-specific provisions for determination of represented values in 10 CFR 429.43

Includes provisions in 10 CFR 429.43 specific to VRF multi-split systems to determine represented values for models with specific components, and determine represented values for different indoor unit combinations

Establish VRF-specific provisions for determination of represented values.

Includes certification requirements in 10 CFR 429.43 consistent with testing to EER per ANSI/AHRI 1230-2010

Adopts reporting requirements consistent with new test requirements of AHRI 1230-2021, including tested combination, certified critical parameter values, and instructions for conducting the controls verification procedure (“CVP”)

Establish reporting requirements consistent with updated industry test method.

Does not include VRF-specific enforcement provisions in 10 CFR 429.134

Adopts product-specific enforcement provisions for VRF multi-split systems including: verification of cooling capacity, testing of systems with specific components, break-in period, manufacturer involvement in assessment or enforcement testing, provisions for when DOE would conduct a CVP, and how CVP results would affect critical parameters used in IEER enforcement testing by DOE

Establish provisions for DOE testing of VRF multi-split systems.

Does not provide VRF-specific instruction for validating alternative methods for determining energy efficiency and energy use (“AEDM”) at 10 CFR 429.70

Specifies VRF-specific AEDM validation criteria that are dependent on indoor unit combinations offered by the manufacturer

Establish AEDM instructions specific to VRF multi-split systems.

DOE has determined that the amendments described in section III of this document regarding the establishment of appendix D do not alter the measured efficiency of VRF multi-split systems or require retesting solely as a result of DOE's adoption of the amendments to the test procedure. DOE has determined that the amendments regarding the test procedure in appendix D1 do alter the measured efficiency and are consistent with the updated industry test procedure AHRI 1230-2021. Further, use of the updated industry test procedure provisions and amended representation requirements in 10 CFR 429.43 and 10 CFR 429.70 would not be required until the compliance date of any amended standards based on IEER. Additionally, DOE has determined that the finalized amendments will not increase the cost of testing relative to the updated industry test procedure. The effective date for the amended test procedures adopted in this final rule is 30 days after publication of this document in the

Federal Register

. Discussion of DOE's actions are addressed in detail in section III of this document.

III. Discussion

A. Scope of Applicability

This rulemaking applies to variable refrigerant flow multi-split air conditioners and heat pumps. DOE defines variable refrigerant flow multi-split air conditioners and heat pumps as units of commercial package air conditioning and heating equipment that are configured as a split system air conditioner or heat pump incorporating a single refrigerant circuit, with one or more outdoor units, at least one variable-speed compressor or an alternate compressor combination for varying the capacity of the system by three or more steps, and multiple indoor fan coil units, each of which is individually metered and individually controlled by an integral control device and common communications network and which can operate independently in response to multiple indoor thermostats. 10 CFR 431.92. Variable refrigerant flow implies three or more steps of capacity control on common, inter-connecting piping.

Id.

VRF multi-split heat pumps use reverse cycle refrigeration as its primary heating source and may include second supplemental heating by means of electrical resistance, steam, hot water, or gas.

Id.

DOE is not amending the scope of the Federal test procedure for VRF multi-split systems. DOE's current test procedure regulations for commercial air conditioners and heat pumps at 10 CFR 431.96 include test procedures that apply to air-cooled VRF multi-split air conditioners, air-cooled VRF multi-split heat pumps, and water-source VRF multi-split heat pumps,

all with cooling capacity less than 760,000 Btu/h. Table 1 of 10 CFR 431.96. Single-phase, air-cooled VRF multi-split air conditioners and heat pumps with cooling capacity less than 65,000 Btu/h are subject to DOE's consumer product regulations for central air conditioners, and test procedures for these products are specified in appendices M and M1 to subpart B of part 430. Test procedures for three-phase, air-cooled VRF multi-split systems with cooling capacity less than 65,000 Btu/h are not addressed in this final rule and are instead addressed in a separate test procedure rulemaking for air-cooled, three-phase, small commercial package air conditioning and heating equipment with a cooling capacity of less than 65,000 Btu/h (

see

Docket No. EERE-2017-BT-TP-0031).

The EPCA definition for “commercial package air conditioning and heating equipment” specifically excludes ground water source equipment. (42 U.S.C. 6311(8)(A)).

B. Organization of the VRF Multi-Split System Test Procedure

In the December 2021 VRF TP NOPR, DOE proposed to relocate and centralize the current test procedure for VRF multi-split systems to a new appendix D to subpart F of part 431, such that appendix D would not amend the current test procedure. 86 FR 70644, 70649 (Dec. 10, 2021). The proposed appendix D would also centralize the additional test provisions currently applicable under 10 CFR 431.96 (

i.e.,

optional break-in period for tests conducted using ANSI/AHRI 1230-2010 (10 CFR 431.96(c)); refrigerant line length corrections for tests conducted using ANSI/AHRI 1230-2010 (10 CFR 431.96(d); additional provisions for equipment set-up (10 CFR 431.96(e); and manufacturer involvement in assessment or enforcement testing for variable refrigerant flow systems (10 CFR 431.96(f))). As proposed, VRF multi-split systems would be required to be tested according to appendix D until such time as compliance is required with an amended energy conservation standard that relies on the IEER metric, should DOE adopt such a standard.

Id.

Similarly, DOE proposed to amend the test procedure for VRF multi-split systems by adopting AHRI 1230-2021 in a new appendix D1 to subpart F of part 431. DOE proposed to adopt the updated version of AHRI 1230, including the IEER metric.

Id.

As proposed, VRF multi-split systems would not be required to be tested according to the test procedure in proposed appendix D1 until such time as compliance is required with an amended energy conservation standard that relies on the IEER metric, should DOE adopt such a standard.

Id.

DOE did not receive any comments in response to the proposed organization of the test procedure. Accordingly, for the reasons discussed in the December 2021 VRF TP NOPR and as discussed in the preceding paragraphs, DOE is finalizing the proposed organization of the test procedure by establishing appendices D and D1 for testing VRF multi-split systems.

C. Industry Standards

1. Updates to AHRI 1230

As discussed in section I.B of this document, the VRF TP Term Sheet recommended that DOE adopt the 2019 draft version of AHRI 1230 with several changes, including:

• Adding a hierarchy of instructions for how to set up the unit under test, and a clarification that “as-shipped” settings should be used as a last resort when instructions are not provided in the supplemental testing instructions (“STI”) and/or the manufacturer's installation instructions (“MII”).

• Providing equations and example calculations of adjustments to measured results for steady-state tests if sensible heat ratio (“SHR”)

limits are not met at the 100-percent full-load and/or 75-percent part-load cooling test points.

Cooling load is composed of both sensible and latent portions. The sensible load is the energy required to reduce the temperature of the incoming air, without any phase change. The latent load is the energy required to change the moisture in the air from water vapor into a liquid phase as it condenses on the cooling coil. Sensible heat ratio is a ratio of the sensible cooling capacity to the total cooling capacity at a given test condition.

• Amending the definition of the draft CVP to include a definition of time periods for determining critical parameter validation and allowable critical parameter tolerances using manufacturer-provided data. (Docket No. EERE-2018-BT-STD-0003-0044 at p. 2)

After the VRF ASRAC Working Group meetings in 2019, DOE provided technical support in an AHRI 1230 Technical Committee to address the three outstanding items identified in the VRF TP Term Sheet. For the last item—determining critical parameter tolerances—DOE compiled anonymized, aggregated test data to share with the committee. In a presentation to the AHRI 1230 Technical Committee on September 10, 2020, DOE shared data

on the variability of critical parameter results as measured during different CVP runs, as well as data on how the measured IEER changed in response to changes in critical parameters. (EERE-2018-BT-STD-0003-0063) DOE presented options that could be considered to express the maximum allowable variation in critical parameters as a “budget.” The AHRI 1230 Technical Committee incorporated a budget of 70 points (a measure of critical parameter variation) in the draft AHRI 1230, which is outlined in section III.E.1 of this document.

Following the completion of the AHRI 1230 Technical Committee meetings, in May 2021, AHRI published AHRI 1230-2021, which incorporated the changes consistent with those recommended in the VRF TP Term Sheet. The following list includes substantive changes in AHRI 1230-2021 as compared to ANSI/AHRI 1230-2010, the version currently used for certification:

• Air-cooled VRF multi-split systems with cooling capacity less than 65,000 Btu/h were removed from the scope of the industry test standard. These systems are addressed by AHRI 210/240-2023, “Performance Rating of Unitary Air-conditioning & Air-source Heat Pump Equipment.”

• Maximum SHR limits of 0.82 and 0.85 were added for full-load and 75-percent part-load conditions, respectively.

• A CVP was added that verifies that the values certified in the STI for setting critical parameters during steady-state testing are within the range of critical parameters that would be used by the system's native controls at the same conditions. A 70-point budget was also added as the criteria for critical parameter validation during the CVP.

• A hierarchy was added indicating which sources of manufacturer's instructions to use during testing in the case of conflicting information among different sources.

• Provisions were updated for refrigerant piping length requirements and for the correction factors applied in the case of excess refrigerant piping length used during testing.

• For water-source equipment, the maximum water flow rate was reduced and part-load entering water temperatures were modified.

• New provisions were added to specify test methods and conditions for cases in which condenser head pressure controls result in unstable operation in part-load cooling tests.

• The provisions for tested combinations, which specify the indoor unit combination to be used for testing, were updated to replace “highest sales volume” requirements with a specific hierarchy based on “indoor unit model family” (

e.g.,

wall-mounted, compact 4-way ceiling cassette, mid-static ducted).

• A maximum airflow rate of 55 standard cubic feet per minute (“scfm”) per 1,000 Btu/h was added for non-ducted indoor units, and the maximum airflow rate was increased for ducted indoor units from 37.5 scfm per 1,000 Btu/h to 42 scfm per 1,000 Btu/h.

• Test tolerances for indoor air entering wet-bulb temperatures were increased. Specifically, the indoor wet-bulb temperature operating tolerance was increased from 1 °F to 1.8 °F. The indoor wet-bulb temperature condition tolerance was also increased from 0.30 °F to 0.36 °F. Additionally, the operating tolerance for external static pressure (“ESP”) for ducted units was changed from 0.05 in H

O to 10 percent of the ESP reading.

• Appendix D to ANSI/AHRI 1230-2010 with Addendum 1, “Test Requirements,” was amended in ANSI/AHRI 1230-2021 and redesignated as Appendix E, “ANSI/ASHRAE Standard 37-2009 Clarifications/Exceptions.” This appendix provides additional instruction and exceptions to the use of ANSI/ASHRAE 37-2009.

• Informative appendices were added that show example calculations for IEER and the CVP “budget” method, which calculates the variation between measured critical parameter values and STI-reported critical parameter values.

As part of the December 2021 VRF TP NOPR, DOE evaluated the extent to which a test procedure based on AHRI 1230-2021 would meet the EPCA requirements to produce test results that reflect the energy efficiency, energy use, and estimated operating costs of that equipment during a representative average use cycle, and for such test procedure to not be unduly burdensome to conduct. DOE tentatively concluded that the changes in AHRI 1230-2021 better reflect the field performance of VRF multi-split systems and provide additional clarification for testing provisions. 86 FR 70644, 70650, 70669 (Dec. 10, 2021). DOE also tentatively determined that a test procedure based on AHRI 1230-2021 would not be unduly burdensome to conduct. 86 FR 70644, 70669 (Dec. 10, 2021).

Therefore, DOE proposed to adopt the updated version of AHRI 1230, including the IEER metric, and to incorporate by reference AHRI 1230-2021 in a new appendix D1 to subpart F of part 431. 86 FR 70644, 70650 (Dec. 10, 2021). DOE proposed to reference the following sections from AHRI 1230-2021: Section 3 (except 3.11),

Section 5 (except 5.1.2), Section 6 (except 6.3.3 and 6.5), Section 11, Section 12, and Appendix E. 86 FR 70644, 70650-70651 (Dec. 10, 2021). The remaining sections were excluded as either: (1) informative appendices not needed in the DOE test procedure; (2) procedures specific to the AHRI verification program that are not warranted for a DOE test procedure, or (3) sections for which DOE proposed modifications.

Id.

The CA IOUs stated that in proposed updates to 10 CFR 431.97, subpart F, appendix D1, DOE states that critical parameter(s) are defined in section 3.10 of AHRI 1230-2021, but the correct reference should be to section 3.11 of that industry standard. (CA IOUs, No. 11 at p. 4) DOE acknowledges this typographical error and has corrected the section references in this final rule.

In the December 2021 VRF TP NOPR, DOE included discussion on several test method topics about which DOE requested comment in the July 2017 ASHRAE TP RFI and received stakeholder comments in response to that RFI. These topics included setting indoor airflow and external static pressure, condenser head pressure controls, indoor unit operation during part-load tests, oil recovery mode during transient testing, secondary methods for capacity measurement, and heat recovery. All of these test method topics were addressed in AHRI 1230-2021, and DOE did not propose any deviations from AHRI 1230-2021 on any of the topics. 86 FR 70644, 70653-70656 (Dec. 10, 2021). DOE did not receive any comments regarding these test method topics in response to the December 2021 VRF TP NOPR, but as discussed, the Department did receive comments generally supportive of DOE's proposal to adopt AHRI 1230-2021. Along these lines, Carrier, Lennox, the CA IOUs, AHRI, Daikin, and NEEA all commented that they support DOE's proposal to adopt AHRI 1230-2021. (Carrier, No. 7 at p. 1; Lennox, No. 8 at pp. 1-2; CA IOUs, No. 11 at p. 3; AHRI, No. 12 at p. 2; Daikin, No. 13 at p. 2; NEEA, No. 14 at p. 2) NEEA further commented that AHRI 1230-2021 adds clarifying provisions that will reduce variability in results. (NEEA, No. 14 at p. 2)

For the reasons discussed in the December 2021 VRF TP NOPR and consistent with the comments received in support of DOE adopting AHRI 1230-2021, DOE concludes that as compared to previous versions of AHRI 1230 (including ANSI/AHRI 1230-2010 which is referenced in the current Federal test procedure), AHRI 1230-2021 generally provides results that are more representative of an average use cycle for VRF multi-split systems, provides additional clarification for

testing provisions, and is not unduly burdensome to conduct. In particular, DOE finds that AHRI 1230-2021 includes several test procedure amendments that better reflect typical operation and performance of VRF indoor units, including the addition of SHR limits, further specification of indoor airflow, and changes to indoor unit tested combinations. DOE also finds that the addition of the CVP in AHRI 1230-2021 (which DOE is adopting in enforcement provisions) will improve representativeness by more closely tying controls behavior during testing to controls behavior that would be expected to occur in a field installation under native controls. Therefore, in this final rule DOE is incorporating by reference AHRI 1230-2021 and adopting specific sections for testing VRF multi-split systems as proposed. Sections of AHRI 1230-2021 for which DOE is adopting modifications are discussed in following sections of this final rule.

2. ASHRAE 37

ANSI/ASHRAE Standard 37, which provides a method of test for many categories of air conditioning and heating equipment, is referenced for testing VRF multi-split systems by ANSI/AHRI 1230-2010, ANSI/AHRI 1230-2014 with Addendum 1, and AHRI 1230-2021. ANSI/ASHRAE 37-2005 is referenced in ANSI/AHRI 1230-2010, which is the currently referenced industry test standard in the DOE test procedure for VRF multi-split systems.

ANSI/ASHRAE 37-2009 is referenced in ANSI/AHRI 1230-2014 with Addendum 1 and AHRI 1230-2021. To reflect the use of ANSI/ASHRAE 37-2009 in conducting testing according to AHRI 1230-2021, DOE proposed in the December 2021 VRF TP NOPR to incorporate by reference ANSI/ASHRAE 37-2009 (except for sections 1, 2, and 4) including the errata sheet issued March 27, 2019 (which corrected the total heating capacity equations for the outdoor liquid coil method in section 7.6.5.1 of that test standard)

in the proposed appendix D1 for the VRF multi-split systems test procedure. 86 FR 70644, 70651 (Dec. 10, 2021). DOE did not receive any comments in response to its proposal to reference ASHRAE 37-2009 in the test method for VRF multi-split systems. Accordingly, DOE concludes that ASHRAE 37-2009 is an integral component of testing VRF multi-split systems (per the 2014 and 2021 versions of AHRI 1230) and that it ensures representativeness and repeatability of the test procedure by specifying instrumentation requirements, test set-up provisions, calculation methods, and test tolerances. Therefore, DOE incorporates by reference ANSI/ASHRAE 37-2009 (as corrected by the most recent errata sheet issued March 27, 2019) and adopts the relevant sections for testing VRF multi-split systems, as proposed.

In the December 2021 VRF TP NOPR, DOE incorrectly stated that ANSI/AHRI 1230-2010 references ANSI/ASHRAE 37-2009. 86 FR 70644, 70651 (Dec. 10, 2021).

The errata sheet, which was updated on March 27, 2019, is available at:

www.ashrae.org/file%20library/technical%20resources/standards%20and%20guidelines/standards%20errata/standards/37-2009errata-3-27-2019-.pdf

(Last accessed Sept. 7, 2022).

D. Metrics

1. IEER

In the December 2021 VRF TP NOPR, DOE provided considerable background on the IEER metric, and the Department proposed to adopt the IEER metric and the relevant provisions in AHRI 1230-2021 to determine IEER for VRF multi-split systems. DOE currently prescribes energy conservation standards for air-cooled VRF multi-split systems with cooling capacity greater than or equal to 65,000 Btu/h and water-source VRF multi-split heat pumps in terms of the EER metric for cooling-mode operation and in terms of the COP metric for heating-mode operation. EER and COP capture the system performance at single, full-load operating points in cooling and heating mode, respectively (

i.e.,

single outdoor air temperatures for air-cooled systems and single entering water temperatures for water-source systems). Neither metric provides a seasonal or load-weighted measure of energy efficiency. 86 FR 70644, 70651 (Dec. 10, 2021).

In contrast, the IEER metric factors in the efficiency of operating at full-load conditions as well as part-load conditions of 75-percent, 50-percent, and 25-percent of full-load capacity. In general, the IEER metric provides a more representative measure of field performance by weighting the full-load and part-load efficiencies by the average amount of time equipment spends operating at each load.

Id.

IEER was first specified in a 2008 supplement to ASHRAE Standard 90.1-2007 for commercial air-cooled, water-cooled, and evaporatively-cooled air conditioning and heat pump equipment. ASHRAE Standard 90.1-2010 included minimum efficiency levels in terms of both EER and IEER for air-cooled VRF multi-split systems. ASHRAE Standard 90.1-2016 added IEER levels for water-source VRF multi-split heat pump systems, including systems with cooling capacity less than 65,000 Btu/h, in addition to the specified EER levels. On January 15, 2016, DOE published a direct final rule in the

Federal Register

for energy conservation standards for air-cooled commercial unitary air conditioners (air-cooled CUACs, or ACUACs), which amended the energy conservation standards for ACUACs and changed the cooling efficiency metric from EER to IEER, with compliance required starting January 1, 2018. 81 FR 2420.

The proposal to adopt the IEER metric and relevant provisions of AHRI 1230-2021 in the test procedure for VRF multi-split systems aligned with the VRF TP Term Sheet upon which the ASRAC Working Group agreed. 86 FR 70644, 70652 (Dec. 10, 2021). DOE also proposed to amend the definition for IEER at 10 CFR 431.92 to distinguish between the test procedures for ACUACs and VRF multi-split systems.

Id.

Lennox, the CA IOUs, AHRI, Daikin, and NEEA commented that they support DOE's proposal to adopt the IEER metric for VRF multi-split systems. (Lennox, No. 8 at pp. 1-2; CA IOUs, No. 11 at p. 3; AHRI, No. 12 at p. 2; Daikin, No. 13 at p. 2; NEEA, No. 14 at p. 2) Lennox and NEEA stated that IEER improves the representativeness of the tested value for VRF multi-split systems. (Lennox, No. 8 at p. 2; NEEA, No. 14 at p. 2) The CA IOUs and NEEA commented that IEER informs consumers of the part-load performance benefits of variable speed equipment. (CA IOUs, No. 11 at p. 3; NEEA, No. 14 at p. 2) AHRI, Daikin, and Lennox supported DOE's proposed revision to the definition of IEER to differentiate between the test procedures for ACUAC and VRF multi-split systems. (AHRI, No. 12 at p. 2; Daikin, No. 13 at p. 2; Lennox, No. 8 at p. 2)

NEEA commented that DOE should investigate the differences between AHRI 1230-2021 and ANSI/AHRI 1230-2010, because manufacturers currently certify IEER measured per 1230-2010 for the AHRI certification program. The commenter stated that testing according to the new version of AHRI 1230 could result in different IEER values, which could cause market confusion, so NEEA suggested that DOE consider changing the name of the metric measured per AHRI 1230-2021 to “IEER2.” (NEEA, No. 14 at p. 2)

Regarding NEEA's comment, the changes in AHRI 1230-2021 as compared to ANSI/AHRI 1230-2010 better reflect typical operation and performance of VRF multi-split systems (see section III.C.1 of this document for further discussion). In particular, DOE

finds that AHRI 1230-2021 includes several test procedure amendments that better reflect typical operation and performance of VRF indoor units, including the addition of SHR limits, further specification of indoor airflow, and changes to indoor unit tested combinations. DOE also finds that the addition of the CVP in AHRI 1230-2021 (which DOE is adopting in enforcement provisions) will improve representativeness by more closely tying controls behavior during testing to native controls behavior that would be expected to occur in a field installation. DOE also notes that the VRF TP Term Sheet included as Recommendation #1 that VRF multi-split systems should be rated with the IEER metric. (Docket No. EERE-2018-BT-STD-0003-0044) This recommendation was unanimously agreed upon by all Working Group members, as it allowed for comparisons to CUAC ratings, which also use the IEER efficiency metric. Further, DOE does not require certification of IEER as measured per ANSI/AHRI 1230-2010 nor does it include IEER in its current test procedure for VRF multi-split systems. Therefore, DOE concludes that there is not a need to deviate from the metric name “IEER” specified in AHRI 1230-2021 and that doing so might spawn unnecessary confusion by suggesting that there is some significant difference as to how that term is used in the context of the amended Federal test procedure as compared to AHRI 1230-2021. Consequently, DOE is adopting the IEER metric measured per AHRI 1230-2021 in the Federal test procedure for VRF multi-split systems, as proposed. Further, DOE is adopting the proposed revisions to the definition for IEER at 10 CFR 431.92 to distinguish between the test procedures for ACUACs and VRF multi-split systems.

2. Test Conditions Used for Efficiency Metrics

AHRI 1230-2021 includes a number of test conditions used to determine rated performance of VRF multi-split systems in both cooling mode and heating mode. Standard rating tests in cooling mode include the full-load cooling and three part-load cooling tests used to determine IEER. Standard rating tests in heating mode differ depending on whether the VRF multi-split heat pump is water-source or air-source. For water-source systems, there is only one heating mode standard rating test. For air-source systems, there are two heating mode standard rating tests (one at 47 °F outdoor temperature and another at 17 °F outdoor temperature).

In the December 2021 VRF TP NOPR, DOE proposed to specify in the test procedure for VRF multi-split systems which test conditions would be required for compliance with standards, were DOE to amend the energy conservation standards based on AHRI 1230-2021, and to specify additional test conditions that would be included in the DOE test procedure for making optional representations of efficiency. 86 FR 70644, 70652-70653 (Dec. 10, 2021). Specifically, for air-cooled VRF multi-split systems, DOE proposed to specify in section 3.1 of the proposed appendix D1 that the cooling test conditions used for compliance would be the “Standard Rating Conditions, Cooling” and “Standard Rating Part-Load Conditions (IEER)” conditions specified in Table 8

of AHRI 1230-2021. DOE also proposed to specify in section 4.1 of the proposed appendix D1 that the heating test condition used for compliance would be the “Standard Rating Conditions, High Temperature Steady-State Test for Heating” conditions (47 °F) specified in Table 8 of AHRI 1230-2021. DOE also proposed to specify in section 4.1.1 of the proposed appendix D1 that representations of COP would be optional for the “Low Temperature Steady-state Test for Heating” conditions (17 °F), also specified in Table 8 of AHRI 1230-2021. For water-source VRF multi-split heat pumps, DOE proposed to specify in section 3.2 of the proposed appendix D1 that the test conditions used for compliance would be the standard rating test conditions for “Water Loop Heat Pumps” and proposed in section 4.2.1 of proposed appendix D1 that representations of EER and COP at the standard rating conditions for “Ground-loop Heat Pumps” would be optional.

Id.

AHRI commented in response to the December 2021 NOPR that DOE incorrectly identified the relevant table numbers of AHRI 1230-2021. They clarified that Table 8 of AHRI 1230-2021 outlines “standard rating conditions” for air-source VRF multi-split systems, while Tables 9 and 10 provide these conditions for water-source VRF multi-split systems for cooling mode and heating mode, respectively. (AHRI, No. 12 at p. 10) DOE has corrected these references in this final rule.

In response to DOE's proposed rating conditions, NYSERDA encouraged DOE to work with industry stakeholders to improve the representativeness of heating-mode performance ratings by: (1) adding rating points at colder ambient temperatures and (2) encouraging DOE to shift from regulating based on a single test point to an integrated heating metric. NYSERDA asserted that the VRF heating performance rating (COP at 47 °F) does not provide customers with sufficient information to determine equipment performance at temperatures experienced by New Yorkers during much of the winter season. Specifically, the commenter advocated that a rating condition at colder temperatures such as 5 °F or 0 °F is needed to provide colder climates with the data necessary to determine which VRF equipment is most appropriate. NYSERDA also encouraged DOE to change the test condition used for determining heating capacity from 47 °F to 17 °F (or lower). Regarding an integrated heating metric, NYSERDA commented that although integrated ratings are not reflective of any specific building type or climate zone, they provide a relative ranking of products, thereby allowing consumers to understand which models are likely to perform better than others across a range of ambient temperatures and load levels on the equipment. NYSERDA commented that an integrated heating metric for VRFs would be more representative than COP at 47 °F. (NYSERDA, No. 6 at p. 2) Furthermore, NYSERDA requested that if its comments could not be addressed in the current rulemaking, then it asked DOE to consider its comments for the next update of VRF test procedures. (NYSERDA, No. 6 at p. 3) No other comments were received as to the proposed test conditions for VRF multi-split systems.

In response, DOE notes that for VRF multi-split systems, the generally accepted industry test procedure is AHRI 1230-2021, which for air-source heat pumps only includes provisions to determine the COP rating at a high temperature point of 47 °F and at a low temperature point of 17 °F (outdoor air dry-bulb temperatures). Neither AHRI 1230-2021 nor previous versions of AHRI 1230 include the provisions needed to determine heating performance at other outdoor temperatures or specify an integrated metric for heating.

Regarding the addition of heating conditions at temperatures colder than 17 °F or adoption of an integrated heating metric (which as described by NYSERDA, would involve adding part-load heating tests), at this time, DOE lacks sufficient evidence to adopt tests for VRF multi-split systems at conditions other than those specified in the updated industry consensus test procedure, AHRI 1230-2021. Further, DOE does not have data as to representative test conditions, load levels, and weighting factors to be included in an integrated heating metric for VRF multi-split systems.

Regarding the suggestion that rated heating capacity be based on performance at 17 °F instead of 47 °F,

NYSERDA did not provide evidence that heating capacity measured at 17 °F would be more representative for VRF multi-split systems for the nation as a whole. Further, all other commercial heat pump equipment categories regulated by DOE also have the rated heating capacity measured at 47 °F, thus allowing comparison at the same condition across equipment categories. Additionally, the AHRI

Directory of Certified Product Performance

includes heating capacity measured at both 47 °F and 17 °F; therefore, to the extent stakeholders are interested in heating capacity of VRF multi-split systems at 17 °F, they can obtain such information from the data made publicly available in the AHRI Directory for systems included in AHRI's certification program.

The AHRI directory for VRF multi-split systems is available at:

www.ahridirectory.org/NewSearch?programId=72&searchTypeId=3

(Last accessed July 8, 2022).

DOE notes that NYSERDA acknowledged that the Department is finalizing its test procedure rulemaking for VRF multi-split systems and that the commenter's suggestions may not be able to be incorporated in this rulemaking. Absent data supporting the representativeness of alternate test conditions and an alternate metric, as well as a lack of information as to which test conditions would be included in a representative integrated heating metric, DOE is not considering test conditions or metrics for VRF multi-split systems other than those proposed in the December 2021 VRF TP NOPR. Therefore, DOE is not adopting a lower-temperature heating test or an integrated heating metric for VRF multi-split systems, as recommended by NYSERDA. For the reasons discussed in the December 2021 VRF TP NOPR and in the preceding paragraphs, DOE is finalizing its proposals from the December 2021 VRF TP NOPR regarding test conditions for VRF multi-split systems.

E. Controls Verification Procedure

Section 5.1.2.1 of AHRI 1230-2021 specifies that during steady-state performance rating tests for cooling and heating efficiency, VRF multi-split systems must operate under commands from system controls except for certain components, referred to as “critical parameters,” which are allowed to be set by a manufacturer's representative. These critical parameters are (1) compressor speed(s), (2) outdoor fan speed(s), and (3) outdoor variable valve positions. Settings for critical parameters are allowed to be manually controlled using a manufacturer control tool, as opposed to all other components which must operate per commands from the system controls. The measured performance of VRF multi-split systems depends, in part, on the operating positions of each of these critical parameters. Accordingly, Section 5.1.2 of AHRI 1230-2021 states that operational settings for each of the critical parameters must be specified in the STI, and that each of the critical parameters must be allowed to be manually adjusted (to match the STI-certified values) during testing.

AHRI 1230-2021 also includes a normative Appendix C that specifies a CVP. The purpose of the CVP is to validate that the observed positions of critical parameters during the CVP are within tolerance of the STI-certified critical parameter values that are set by the manufacturer in steady-state IEER cooling tests (see section III.E.4 of this final rule for discussion of CVP results). This ensures that the measured results of the IEER test procedure are based on critical parameter settings that are representative of critical parameter behavior that would be experienced in the field. The December 2021 VRF TP NOPR includes additional information about the CVP.

See

86 FR 70644, 70658-70663 (Dec. 10, 2021).

1. Background

DOE's current test procedure for VRF multi-split systems includes allowances in 10 CFR 431.96(f) for limited manufacturer involvement in assessment or enforcement testing. A manufacturer's representative may adjust components such as the compressor speed, fan speeds, and valve positions for the purposes of achieving steady-state conditions during testing. 10 CFR 431.96(f). This adjustment process is provided for VRF multi-split systems because of the complexity of VRF multi-split systems and the variety of settings needed to perform a test. 77 FR 28928, 28946 (May 16, 2012). DOE's current certification requirements for VRF multi-split systems, found at 10 CFR 429.43(b)(4), specify that the STI must include compressor frequency setpoints and required dip switch/control settings for step or variable components. However, DOE's current regulations do not require these settings to match system behavior when the VRF multi-split system is operating under its own controls. Further, there are no constraints regarding the allowable range of adjustments that a manufacturer's representative may make to reach steady-state operation.

In October 2018, during the negotiation meetings of the Working Group, the CA IOUs raised concern (supported by field and laboratory test data) as to the representativeness of the ANSI/AHRI 1230-2010 method, particularly with respect to control inputs used at part-load test conditions. (Docket Nos. EERE-2018-BT-STD-0003-0011 and EERE-2018-BT-STD-0003-0013) Ultimately, the VRF TP Term Sheet from the Working Group recommended that DOE adopt an updated draft of AHRI 1230 that included a controls verification procedure as an appendix. (Docket No. EERE-2018-BT-STD-0003-0044 at pp. 1-2)

Appendix C of AHRI 1230-2021 establishes a CVP.

The CVP verifies whether critical parameter settings certified in the STI, implemented by the manufacturer's representative during full-load and part-load steady-state cooling tests for IEER, are within the range of settings that would be used by the system during operation in the field—the system's native controls. The behavior of each critical parameter is monitored and recorded throughout the duration of a CVP. In contrast to steady-state tests in which test conditions are held constant, the CVP is a dynamic cooling test method in which certain test conditions are intentionally varied throughout the test. Specifically, the indoor room dry-bulb temperature is steadily decreased during the CVP using the room conditioning apparatus, in order to determine how the VRF multi-split system under test responds to approaching and achieving its setpoint. Outdoor room test conditions are held constant during the CVP. The CVP may be conducted at any of the four IEER outdoor air or entering water temperature conditions. At the start of the CVP, the indoor room test chamber temperature is controlled to a manufacturer-specified value that must be between 82 °F and 86 °F, and the VRF indoor units are set to control to a constant indoor temperature, 80 °F, except as explained by Section 5.1.5 of AHRI 1230-2021. Section 5.1.5 provides instructions for adjusting the VRF indoor unit setpoints (deviating from 80 °F) to account for setpoint bias and setpoint offset.

VRF indoor units

typically use the calculated temperature difference between the setpoint and the measured indoor air temperature as a control parameter for determining when to shut down and become thermally inactive.

The concept for the CVP originated from a minimum compressor speed verification procedure provided in Japanese standard JIS B 8616:2006,

Package Air Conditioners,

which is included as an informative reference in appendix B of AHRI 1230- 2021, but not directly referenced within AHRI 1230-2021. Available at

www.jsajis.org/index.php?main_page=product_info&cPath=2&products_id=13290.

AHRI 1230-2021 provides the following definitions for these terms in sections 3.29 and 3.30, respectively:

Setpoint Bias—The difference between 80 °F and the nominal thermostat setpoint required for the thermostat to control for 80 °F sensed temperature at the sensed location.

Setpoint Offset—The difference between the temperature indicated by a thermostat's temperature sensor and the actual temperature at the sensor's location.

As discussed, the timing of the first indoor unit becoming thermally inactive dictates the allowable time period for determining whether certified critical parameter values have been validated, so it is crucial to account for setpoint bias and offset to ensure repeatable test results. After setting initial indoor air temperature, including any adjustments to control for setpoint bias and offset, the CVP proceeds by incrementally decreasing the indoor room test chamber temperature while the VRF multi-split system setpoint is held constant. As the indoor room temperature approaches and eventually passes below the VRF multi-split system setpoint, the VRF multi-split system controls should begin to register that the cooling demand has been satisfied, and the system will begin to “unload,” meaning reduce capacity.

VRF multi-split systems typically unload by modulating component settings, including critical parameters, from the values used when providing full-load cooling capacity.

Figure C.1 in AHRI 1230-2021 displays an example schematic of the indoor dry-bulb temperature in °F, compressor speed in Hz, and the number of thermally active indoor units over the duration of a CVP test.

During this unloading period and up until the time that the first indoor unit becomes thermally inactive, critical parameters are compared against the critical parameter values that are certified in the STI. Once the first indoor unit becomes thermally inactive, the indoor room dry-bulb temperature continues decreasing until the indoor room reaches 77 °F. Section C6 of AHRI 1230-2021 includes equations for determining “RSS Points Total”

—an aggregated and normalized measure of deviation of all critical parameters from their certified values—and also includes criteria for determining whether or not the CVP has validated the certified critical parameter settings. The verification criteria specified in Section C6 of AHRI 1230-2021 for critical parameters measured during the CVP constitute a “budget method” that applies a limit to the calculated RSS Points Total across all three critical parameters instead of applying individual tolerances to each individual critical parameter.

This method allows manufacturers flexibility in critical parameter control strategies while still constraining the overall variation in VRF multi-split system performance. The budget method can be applied the same way regardless of the number of critical parameters that a manufacturer certifies to their STI. For any critical parameter whose value is not certified in the STI, (

i.e.,

not designated as being controlled during the IEER cooling tests), the deviation in that parameter will be calculated as zero for the duration of the CVP. Section C6.1.2 of AHRI 1230-2021 specifies that the certified critical parameters are valid if at least one measurement period of at least three minutes and a minimum of five sample readings exists where the average RSS Points Total is less than or equal to 70 points. Section C6.1.3 specifies the converse,

i.e.,

if no such measurement period satisfying those critical parameters exists within the CVP, then certified critical parameter values are deemed invalid. As discussed and for the reasons explained in the following sections, DOE is generally adopting the CVP provisions as proposed in the December 2021 VRF TP NOPR.

In response to the December 2021 NOPR, the CA IOUs commented that there were certain incorrect section references in the December 2021 NOPR. They stated that proposed changes to 10 CFR 429.134(s)(3)(ii)(B) state that the RSS points total is defined in Section 3.26 of AHRI 1230-2021, while the definition is actually in section 3.27. (CA IOUs, No. 11 at p. 4). DOE has corrected the section references in this final rule.

In addition to recommending inclusion of a CVP as an appendix to the draft AHRI 1230, the VRF TP Term Sheet also recommended that DOE determine appropriate values for critical parameter tolerances using manufacturer-provided data. DOE subsequently conducted testing and sensitivity analysis of several VRF multi-split systems. The results were used to develop the “budget method” for CVP critical parameter verification specified in Section C6 of AHRI 1230-2021.

2. When the CVP Is Conducted

In the December 2021 VRF TP NOPR, DOE proposed to adopt the CVP that is specified in appendix C of AHRI 1230-2021 in the product-specific enforcement provisions for VRF multi-split systems at 10 CFR 429.134(s). 86 FR 70644, 70661 (Dec. 10, 2021). Additionally, DOE proposed to specify at 10 CFR 429.134(s)(3) that DOE would conduct a CVP at each of the four IEER cooling test conditions in the December 2021 VRF TP NOPR.

Id.

DOE also proposed to specify that the CVP would be performed first at the full-load cooling condition to determine maximum critical parameter values, before conducting the CVP at part-load cooling conditions because the maximum critical parameter values are used for calculating normalized deviation for CVPs at part-load conditions.

Id.

The CA IOUs, Daikin, and AHRI commented that they support DOE's proposal to incorporate the CVP into its product-specific enforcement provisions. (CA IOUs, No. 11 at p. 2; Daikin, No. 13 at p. 4; AHRI, No. 12 at p. 5) The CA IOUs stated that this proposal captured the intent of the VRF TP Term Sheet and that this proposal will capture the benefits of the CVP while limiting test burden primarily to the systems included in enforcement testing. (CA IOUs, No. 11 at p. 2)

NEEA commented that the CVP is an essential process to verify that the system can perform according to its rating. NEEA recommended that the CVP should be required as a part of the test procedure, not only included in enforcement provisions. The commenter stated that, without performing a CVP as part of the test procedure, the manufacturer may not be aware that its equipment is underperforming until DOE selects it for enforcement testing. (NEEA, No. 14 at pp. 2-3)

Joint Advocates and the CA IOUs commented that they support DOE's proposal to conduct a CVP at each of the four load points. The CA IOUs stated that the CVP is important at part-load conditions, where deviation in the VRF system performance is expected to be largest. (CA IOUs, No. 11 at p. 2; Joint Advocates, No. 9 at p. 2) AHRI and Daikin pointed out that DOE's proposal to conduct a CVP at each load point would be more than what is required for AHRI's certification program. (AHRI, No. 12 at p. 10; Daikin, No. 13 at p. 7) Daikin further commented that, due to the relative newness of the CVP, manufacturers would likely perform the same CVP tests that DOE would perform as part of enforcement testing, thereby increasing test burden. (Daikin, No. 13 at p. 7) AHRI further commented that other than conducting the CVP at all load points, the burdens of the NOPR proposals are similar to current industry practice as indicated by AHRI 1230-2021. (AHRI, No. 12 at p. 10)

With regards to NEEA's comment, DOE did consider the potential burden and benefits of including the CVP as part of the Federal test procedure, and this evaluation revealed the following. To start, DOE notes that the CVP is not required for rating models as part of the industry consensus test procedure (AHRI 1230-2021). Per the certification requirements adopted in this final rule (see section III.G.2.b of this document), manufacturers will be required to report

the critical parameter settings at each of the IEER test conditions as part of their STI. Consequently, DOE expects that manufacturers likely will develop these certified values first through investigative testing of some basic models and then later, as knowledge of VRF control systems improves, through simulations. However, DOE expects that manufacturers may determine that they do not need to conduct the CVP on every basic model in order to understand the behavior of the system controls to develop certified critical parameters. For instance, a manufacturer may conduct a CVP on one or two models within a model line and find that the resulting information provides an adequate basis to develop certified critical parameters for other models in the model line (

e.g.,

similar models of differing capacities). Further, manufacturers likely will have some understanding of the dynamic system controls behavior of their models without conducting the CVP. Requiring conducting the CVP for rating every basic model would not provide manufacturers this discretion, and it could result in unnecessary and costly testing.

Requiring the CVP to be conducted for every basic model would require manufacturers to physically test every basic model of VRF multi-split systems. Per current regulations at 10 CFR 429.43 and 10 CFR 429.70, manufacturers are allowed to rate VRF multi-split systems using AEDMs and are not required to test every basic model. Therefore, requiring the CVP to be conducted for every basic model would substantially increase the number of basic models required to be physically tested. Further, as described in the December 2021 VRF TP NOPR, DOE estimated that the CVP would add approximately eight hours of test time at each of the four IEER load conditions during enforcement testing. 86 FR 70644, 70669 (Dec. 10, 2021). If the CVP were required to be used at each IEER test condition, each basic model would potentially require over 30 hours of testing time for the CVP, beyond the testing time required to measure IEER.

Because manufacturers likely will conduct CVP testing and simulation on a number of their VRF models in order to determine representative certified settings for critical parameters in the STI for all basic models, DOE finds that NEEA's suggestion to include the CVP as part of the test procedure for VRF multi-split systems would not substantially change the critical parameter settings manufacturers would certify, and, thus, would not provide a significant increase in representativeness of the test procedure. Further, NEEA's suggestion would impose significantly more burden on manufacturers than the approach proposed in the December 2021 VRF TP NOPR, because it would require physical testing and conducting the CVP for every basic model, rather than allowing manufacturers to decide the appropriate balance of CVP testing and test burden to develop certified critical parameter settings. Contrary to what NEEA suggests, DOE also finds it unlikely that manufacturers would not take appropriate steps to assess their equipment's performance under the CVP, particularly given the potential business disruptions likely to result were underperformance to be encountered for the first time in the context of DOE enforcement testing. Given that not requiring the CVP for testing is consistent with the VRF TP Term Sheet and the most recent industry consensus test procedure, DOE does not have sufficient evidence to conclude that requiring the CVP for testing would improve the representativeness of the test procedure without being unduly burdensome. Therefore, DOE is adopting the CVP as product-specific enforcement provisions for VRF multi-split systems in 10 CFR 429.134(s) as proposed.

With regard to conducting the CVP at all four IEER load points, DOE found through its investigative testing that there is substantial variability in VRF system behavior observed at different IEER load points, and that the system controls behavior at one IEER point does not necessarily predict behavior at a different load point. Therefore, DOE concludes that separately validating critical parameter behavior at each IEER condition is needed as part of DOE enforcement testing in order to sufficiently ensure representative system controls behavior. In consideration of these factors and comments received, in this final rule, DOE is adopting its proposals at 10 CFR 429.134(v)(3) regarding performing a CVP at full-load cooling conditions first, then at each of the part-load cooling conditions.

Adoption of the CVP in enforcement provisions will not require manufacturers to conduct the CVP on every basic model. As previously discussed, manufacturers likely will choose not to conduct the CVP for every basic model of VRF multi-split systems, as they may find that simulations, similarity between basic models (particularly between models within a model line), and their understanding of the behavior of their system controls provide sufficient basis to develop certified critical parameter settings for some of their model offerings. To the extent that manufacturers conduct CVP testing on their models in order to sufficiently understand systems behavior, DOE acknowledges that its adoption of CVP testing at all four IEER load points for enforcement testing (rather than just at one IEER load point) may result in manufacturers conducting the CVP at more IEER load conditions than they otherwise would have. DOE acknowledges that in certain scenarios, running three more CVPs could take up to 24 hours. However, by performing the CVP at the same time as IEER testing, there would be no additional test burden associated with unit set-up/commissioning. Additionally, a CVP could be completed immediately following a steady-state test run at the corresponding IEER load point, in which case there would be no need to change the test chamber temperatures prior to conducting the CVP. Therefore, DOE concludes that for the basic models for which manufacturers choose to conduct the CVP, conducting the CVP at all four IEER load points would not be unduly burdensome and would increase the representativeness of the test procedure. As discussed, DOE has concluded that conducting the CVP at all four IEER load points is needed to ensure representative system behavior. Therefore, DOE is adopting its proposals at 10 CFR 429.134(v)(3) that as part of assessment or enforcement testing, DOE will perform a CVP at full-load cooling conditions first, then at each of the part-load cooling conditions.

In the December 2021 VRF TP NOPR, DOE also proposed to specify that the CVP would be performed on a single system of the two-system sample during enforcement testing. 86 FR 70644, 70661-70662 (Dec. 10, 2021).

AHRI, Lennox, the CA IOUs, and Daikin commented that performing a CVP on a single system is adequate, provided that the testing laboratory ensures the set-up is correct and that a manufacturer representative is involved. (AHRI, No. 12 at p. 5; Lennox, No. 8 at p. 3; CA IOUs, No. 11 at p. 2; Daikin, No. 13 at p. 4)

For the reasons discussed in the December 2021 VRF TP NOPR and in the preceding paragraphs, DOE adopts its proposal to perform the CVP on a single system during assessment or enforcement testing. DOE is clarifying in this final rule that a CVP would be performed on a single system, regardless of the sample size used for enforcement (see section III.G.7 of this document for further discussion of the enforcement sampling plan). DOE's use of the CVP during assessment and enforcement

testing is illustrated in Figure 1 in section II of this final rule.

3. Critical Parameter Definition

In the December 2021 VRF TP NOPR, DOE proposed not to reference the definition of “critical parameters” in Section 3.11

of AHRI 1230-2021 in order to be more explicit that the term “critical parameters” refers only to those parameters specified by Section 5.1.2.1 of AHRI 1230-2021. DOE proposed to define critical parameters in section 3 of appendix D1 as specifically referring to the following settings of modulating components of VRF multi-split air conditioners and heat pumps: compressor speed(s), outdoor fan speed(s) and outdoor variable valve position(s). 86 FR 70644, 70659 (Dec. 10, 2021). DOE tentatively concluded that the proposed change to the definition is editorial in nature and would not change or conflict with any testing provisions in AHRI 1230-2021.

Id.

at 86 FR 70659-70660.

AHRI and Daikin commented that the original definition for critical parameters as written in AHRI 1230-2021 should be used in the DOE test procedure. (AHRI, No. 12 at p. 3; Daikin, No. 13 at p. 2) AHRI stated that Section 5.1.2.1 of AHRI 1230-2021 specifies what the critical parameters are for a given system and stated their preference that this be enumerated in the test requirements rather than the definition so as to align with AHRI 1230-2021. (AHRI, No. 12 at p. 3) Daikin argued that the proposed revision to the definition does not add more specificity to which components can be adjusted. (Daikin, No. 13 at p. 2) The CA IOUs commented that they support DOE's proposed definition for “critical parameters” and limiting the term to the parameters specified in section 5.1.2.1 of AHRI 1230-2021, and they agreed with DOE that the proposal would not conflict with any testing provisions in AHRI 1230-2021. (CA IOUs, No. 11 at p. 4) Lennox commented that they support DOE's proposal to clarify that critical parameters are limited to compressor speeds, outdoor fan speeds, and outdoor variable valve positions, stating that the proposed definition would provide clarity and consistency when conducting a CVP. (Lennox, No. 8 at p. 3)

While section 5.1.2.1 of AHRI 1230-2021 clearly enumerates the three types of components that can be specified for testing and verified by conducting a CVP, the definition of “critical parameter” in AHRI 1230-2021 is rather vague, open-ended, and susceptible to a reading that would permit inclusion of components that cannot be overridden during testing (

i.e.,

components other than compressor speed(s), outdoor fan speed(s) and outdoor variable valve position(s)). DOE concludes that specifying the relevant components in the definition will add clarity to the test procedure without conflicting with existing provisions or adding duplicative language into the test procedure. Therefore, for the reasons discussed in the December 2021 VRF TP NOPR and in this paragraph, DOE is adopting its proposed definition for critical parameters that specifically refers to the relevant components: compressor speed(s), outdoor fan speed(s) and outdoor variable valve position(s).

4. Validation of Certified Critical Parameters

As previously discussed, Sections C6.1.2 and C6.1.3 of AHRI 1230-2021 specify validation criteria for the CVP using a budget method that limits the calculated RSS Points Total across all three critical parameters. In the December 2021 VRF TP NOPR, the Department discussed this matter in some detail, and DOE tentatively determined that the language in Sections C6.1.2 and C6.1.3 of AHRI 1230-2021 could be construed and applied in multiple manners, and that this could lead to differing test burdens. 86 FR 70644, 70660 (Dec. 10, 2021). The phrase “a measurement period of at least three minutes and a minimum of five sample readings” could be misunderstood to indicate a measurement period with no upper limit, potentially encompassing the entire duration of the CVP. This reading could be misunderstood to require iterative calculations of time periods of varying lengths when validating critical parameters during the CVP (

e.g.,

all three-minute periods, and all four-minute periods, and all five-minute periods). Taken to an extreme, this would result in thousands of calculations. Further, the language “where the average RSS Points Total is less than or equal to 70 points” does not indicate the specific procedure for determining the average value of RSS Points Total—

i.e.,

whether “average” refers to the average value within the measurement period or the cumulative average value of RSS points at the time of measurement.

Id.

Accordingly, DOE proposed to clarify these provisions by providing additional instructions for validating critical parameters in 10 CFR 429.134(s)(3)(ii).

Id.

Specifically, DOE proposed to specify that the duration of the time period used for validating critical parameters must be whichever of the following is longer: three minutes or the time period needed to obtain five sample readings while meeting the minimum data collection interval requirements of Table C2 of AHRI 1230-2021.

Id.

DOE also proposed to specify that if at least one measurement period (with the aforementioned duration) exists before the first indoor unit goes thermally inactive that has an average RSS Points Total less than or equal to 70 points, then the certified critical parameter values are validated.

Id.

a. Validation Time Period

Regarding DOE's proposal to clarify the language about the length of time used for the critical parameter validation period, AHRI commented that DOE should not specify a duration for the measurement period used for validating critical parameters. AHRI argued that it is not necessary to change existing language, as increasing testing duration will not improve the ability of the equipment to conform to testing conditions. (AHRI, No. 12 at pp. 3-4) Daikin commented that while they agree with DOE's interpretation that technically a maximum validation time period is not specified in AHRI 1230-2021, a longer test run would result in a higher RSS point total. Daikin stated that this is detrimental to determining whether the critical parameters are valid and asserted that a manufacturer would likely test using the shortest time period permitted by AHRI 1230-2021 (3 to 4 minutes). (Daikin, No. 13 at p. 3) Despite both AHRI and Daikin indicating that a maximum limit for critical parameter validation is not necessary, they acknowledged that there may be merit in adding a maximum time period and suggested changing this period to twice that proposed (

i.e.,

8 minutes). Daikin and AHRI provided three reasons to justify their proposals: (1) there may be difficulty achieving all three critical parameter values at the same time; (2) if any one critical parameter achieves its target setpoint before the other critical parameters, the system is penalized for going beyond the target setpoint; and (3) the newness of the CVP results in greater uncertainty. (AHRI, No. 12 at pp. 3-4; Daikin, No. 13 at p. 3)

In response, DOE understands Daikin's comment to reflect a misunderstanding of the calculation of the RSS points total, by suggesting the potential for accumulating more points as more time passes. As specified in Section C6.1.1 of AHRI 1230-2021, RSS points total is calculated at each data collection interval during the R2 period

as an instantaneous measurement, and, therefore, it does not accumulate over time. AHRI's comments seemingly contradict each other, as it in one place calls for an 8-minute maximum period while at another place it states that a maximum period would have no effect. With respect to AHRI and Daikin's claims about the timing with which critical parameters achieve their target operating states, DOE is aware of the possibility that system controls may achieve desired setpoints for one critical parameter at a different time during the CVP than other critical parameters. However, the purpose of the CVP is to validate that the measured results of the IEER test procedure are based on critical parameter settings that are representative of critical parameter behavior that would be experienced in the field. Because the measured performance of VRF multi-split systems is dependent on the

simultaneous

interaction of each of the critical parameters, critical parameter variation must be evaluated based on the simultaneous positions of each parameter, not based on the behavior for each parameter at different periods of the CVP. Therefore, DOE concludes that for representative IEER test results, the critical parameter settings used in IEER testing should be representative of a combination of setpoints that would be used simultaneously in real-word applications. If the desired critical parameter setpoints are achieved in the CVP at times far enough apart that the RSS Points Total limit is not met within the maximum length of validation period, then the certified critical parameter settings should be invalidated (

i.e.,

not used for steady-state IEER testing). Daikin and AHRI also did not provide any evidence to support their suggestion for increasing the duration of the validation period beyond the duration in DOE's proposed clarification of Sections C6.1.2 and C6.1.3 of AHRI 1230-2021. Because, as discussed in section III.C.1 of this document, the Working Group unanimously recommended that DOE adopt a test procedure referencing AHRI 1230-2021, DOE understands AHRI 1230-2021 to represent the industry consensus opinion. By extension, DOE understands the critical parameter validation time period between 3-4 minutes specified in AHRI 1230-2021 to reflect consensus on an appropriate validation time interval that provides for sufficient data collection and representative results.

Section C4.4.2 of AHRI 1230-2021 defines the “R2 period” as beginning when the measured indoor dry-bulb temperature first crosses from above 82 °F to below 82 °F, and as ending when any indoor unit that was designated thermally active at the start of the CVP becomes thermally inactive.

For the reasons discussed in the December 2021 VRF TP NOPR and in the preceding paragraphs, in this final rule, DOE is adopting its proposal to specify in 10 CFR 429.134(v)(3)(ii) the duration of the time period used for validating critical parameters. The additional instruction results in a validation period lasting a minimum of three minutes and a maximum of four minutes. For tests using the longest allowable data collection interval,

the time required to obtain five sample readings would be four minutes (once at the start of the interval plus four successive measurements, once each minute). For tests using shorter data collection intervals, the validation time period would be either the time required to achieve five sample readings or three minutes, whichever is longer.

Table C2 of AHRI 1230-2021 specifies the minimum data collection intervals for recording data during the CVP.

b. Validation Criteria

Regarding DOE's proposal to validate certified critical parameters based on the presence of a period (with duration discussed in section III.E.4.a of this document) having an average RSS points total less than or equal to 70 points, the CA IOUs commented that they agree that the RSS Point Total budget of 70 points should be large enough to account for any potential source of variability. (CA IOUs, No. 11 at pp. 2-3) In contrast, AHRI and Daikin commented that CVP testing has only been conducted on a limited subset of products, with very few water-source products and no products over 240,000 Btu/h. These commenters further asserted that no lab-to-lab test validation has been conducted, especially between manufacturer laboratories and third-party laboratories. AHRI and Daikin also asserted that manufacturers have observed that changes in the indoor chamber temperature ramp rate impact the unit's ability to meet the average RSS points total and to reach conditions of the CVP. For these reasons, AHRI and Daikin recommended that in the case that a CVP invalidates the certified critical parameter settings during enforcement testing, DOE should require that a second CVP be conducted at an adjusted ramp rate to re-attempt validation. (AHRI, No. 12 at pp. 4-5; Daikin, No. 13 at pp. 3-4)

Regarding AHRI and Daikin's claims about the potential for variation between different CVP test runs, as discussed in section III.E.1 of this final rule, the budget method (adopted at 10 CFR 429.134(v)(3)(ii) in this final rule) allows manufacturers flexibility in critical parameter control strategies while still constraining the overall variation in VRF multi-split system performance. Following Working Group meetings, DOE conducted testing and sensitivity analysis of several VRF multi-split systems, the results of which were incorporated into the development of the budget method for CVP critical parameter verification specified in Section C6 of AHRI 1230-2021. The 70-point threshold was developed as part of AHRI 1230 Technical Committee meetings in which DOE presented anonymized and aggregated test data. As part of those meetings, DOE presented its finding that a minimum point budget of 32 points was required to account for the lab-to-lab and test-to-test variability observed in critical parameter behavior between CVP runs for a single system. (EERE-2018-BT-STD-0003-0063 at p. 23) To account for additional variability (

e.g.,

sample-to-sample variability across the same VRF multi-split system and variability across different types of VRF multi-split systems), DOE recommended a 60-point budget to the Technical Committee. (

) The Technical Committee ultimately agreed to specify a 70-point budget in AHRI 1230-2021. Additionally, in the December 2021 VRF TP NOPR, DOE specifically requested test data demonstrating any issues with repeatability and reproducibility of the CVP that would indicate that the 70-point budget for critical parameter variation included in the industry consensus test procedure AHRI 1230-2021 is insufficient. 86 FR 70644, 70662 (Dec. 10, 2021). DOE did not receive any data in response to this request. For these reasons, DOE concludes that based on all available data, the RSS points total budget of 70 points is appropriately flexible to account for any issues with lab-to-lab and unit-to-unit repeatability when conducting the CVP.

With regard to AHRI and Daikin's proposal to allow a second CVP to be conducted at an alternate ramp rate, DOE does not have sufficient information to support such an addition. As codified in this final rule, manufacturers will be responsible for reporting in their STI specific

instructions for conducting the CVP including ramp rate, starting temperature, and thermally active indoor units. The CVP then includes provisions for ensuring that the test laboratory properly conducts the CVP per manufacturer specifications. Manufacturers also will be required to report certified critical parameter values in their STI, which the manufacturer may develop based on a CVP conducted using the same instructions. These three provisions are all aligned to ensure the CVP is performed consistently and that results are more predictable (

i.e.,

manufacturers can set their own ramp rate and CVP conditions, within bounds of the test procedure, that would provide the most consistent results). Additionally, DOE reiterates that the budget method used for validating critical parameters was designed to give enough flexibility to account for lab-to-lab and test-to-test variation in CVP results. Allowing an additional CVP run to attempt validation of critical parameters would in effect expand the uncertainty allowance beyond that agreed upon by the AHRI 1230 Technical Committee and addressed in AHRI 1230-2021. Therefore, in this final rule DOE is not adopting the suggestion to allow a second CVP to be conducted at an alternate ramp rate.

AHRI further commented that if DOE's proposals regarding CVP validation of certified critical parameters were implemented as enforcement guidance instead of through regulation, then the provisions could be changed or rescinded more easily as industry gains experience with conducting the CVP. (AHRI, No. 12 at p. 5)

As discussed, the CVP provisions (including the RSS points total budget of 70 points) were developed using the data gathered by testing several VRF multi-split systems. These data showed that a 70-point budget would be sufficient to account for lab-to-lab and unit-to-unit test variability. The provisions have also been thoroughly discussed in Working Group and AHRI 1230 Technical Committee meetings prior to inclusion in the most recent industry consensus test procedure AHRI 1230-2021. Therefore, DOE concludes that the CVP provisions are appropriate for inclusion in DOE's regulations. Further, DOE finds that codifying the CVP provisions in regulation provides greater certainty for when and how the CVP would be used and prevents sudden shifts in policy or interpretation.

Based on discussion in the December 2021 VRF TP NOPR and in the preceding paragraphs, DOE is adopting its proposal at 10 CFR 429.134(v)(3)(ii) specifying that if at least one measurement period (with the aforementioned duration) exists before the first indoor unit goes thermally inactive that has an average RSS Points Total less than or equal to 70 points, then the certified critical parameter values are validated.

5. Determination of Alternate Critical Parameters

In the December 2021 VRF TP NOPR, DOE proposed that in cases in which a CVP is not conducted, or if a CVP is conducted and the manufacturer-specified critical parameters are validated, the critical parameter values certified in the STI are to be used as the initial control inputs when conducting the IEER cooling test at the corresponding full- or part-load cooling condition. 86 FR 70644, 70661 (Dec. 10, 2021). In cases in which a CVP fails to validate the certified critical parameter values, DOE proposed at 10 CFR 429.134(s)(3)(iii)(B) that alternate critical parameter values would be determined by averaging the value for each critical parameter from a specified time period of the CVP data, and that these alternate critical parameter values would be used for IEER testing in lieu of the certified critical parameter values.

Id.

To provide further specification for determining these alternate parameters, DOE proposed to use the same procedure for determination of measurement period length as was proposed for validation of certified critical parameters in 10 CFR 429.134(s)(3)(ii)(A): the longer of three minutes or the time period needed to obtain five sample readings while meeting the minimum data collection interval requirements of Table C2 of AHRI 1230-2021. 86 FR 70644, 70661 (Dec. 10, 2021). DOE also proposed to select the measurement period for determining alternate critical parameter values (with the aforementioned duration) that has the lower average RSS points total over the selected period than over any other period in the CVP having the same duration.

Id.

If multiple such periods exist with the same RSS Points Total, DOE proposed to select the period closest to (but before) the time when the first indoor unit becomes thermally inactive (t

Off

Id.

Daikin agreed that neither the Working Group nor the AHRI 1230 Technical Committee resolved the question of how to determine alternate critical parameter values in the case where a CVP invalidates the manufacturer's certified values. Daikin concurred with DOE's suggested approach for determining alternate critical parameter settings. (Daikin, No. 13 at p. 3) DOE did not receive any other comments specific to the question of how to determine alternate critical parameters following a CVP that fails to validate the manufacturer-certified critical parameter settings. For the reasons discussed in the December 2021 VRF TP NOPR and in this section, DOE is adopting the provisions for determining alternate critical parameter values in this final rule as proposed.

F. Allowable Critical Parameter Adjustment

1. Adjustment of Certified Critical Parameter Values

Section 6.3.3 of AHRI 1230-2021 provides instructions for adjusting critical parameters during the four specified full- or part-load IEER cooling test conditions in order to meet cooling capacity targets or to adjust SHR to below the allowable limit. In the December 2021 VRF TP NOPR, DOE tentatively determined that amendments to this section of AHRI 1230-2021 are required and proposed to specify allowable critical parameter adjustments in section 5.2 of appendix D1 to subpart F of part 431. 86 FR 70644, 70662 (Dec. 10, 2021). Specifically, DOE proposed (1) instructions for calculating critical parameter variation (in terms of RSS Points Total) for steady-state IEER cooling tests for which the measured capacity is above the target load fraction; (2) clarification that upward adjustments to compressor speed (

i.e.,

when the measured cooling capacity is too low or when the SHR is above the allowable limit) are not constrained by a budget on RSS Points Total; and (3) clarification to the instructions for calculating critical parameter variation in the scenario where a VRF multi-split system contains multiple components corresponding to a single critical parameter (

e.g.,

multiple compressors).

Id.

at 86 FR 70662-70663.

Daikin expressed support for DOE's proposal to calculate normalized critical parameter variation during the adjustment process if tested capacity is above the target capacity and also supported the proposal to adjust critical parameters to meet capacity requirements. (Daikin, No. 13 at p. 4) AHRI supported the clarifications proposed by DOE and commented that the Department should provide example calculations for each case so as to provide additional clarity. Specifically, AHRI mentioned that for systems with multiple modules (

i.e.,

outdoor units), there are two types of critical parameters: (1) those that can be set for each module and (2) those that have one

value for multiple modules. (AHRI, No. 12 at p. 6)

For the reasons discussed in the December 2021 VRF TP NOPR and in the preceding paragraphs, DOE is finalizing its proposals to add clarifying language to the provisions for determining allowable critical parameter adjustments when conducting IEER testing.

Regarding AHRI's request that DOE provide example calculations for “each case” describing allowable critical parameter adjustments, the scope of AHRI's suggestion is unclear (

e.g.,

whether AHRI requested example calculations for different equipment classes of VRF multi-split systems or for different permutations of critical parameters). Further, DOE finds that the proposed instructions for critical parameter adjustments are sufficient for testing multi-module VRF multi-split systems, even if parameters are controlled jointly across modules. Section 5.2 of appendix D1 describes critical parameter adjustments and includes provisions that accommodate differential or shared adjustments of multiple instances of the same critical parameter (

e.g.,

two compressors). Because the existing test provisions sufficiently cover the scenario described by AHRI, and because AHRI did not provide any other examples of VRF multi-split system configurations or control schemes for which the proposed testing provisions for critical parameter adjustments are unclear, DOE is not adding example calculations for critical parameter adjustments in this final rule.

In the case that a VRF multi-split system configuration exists that raises questions about how the DOE test procedure should apply, DOE notes that it will receive general inquiries via email at

ApplianceStandardsQuestions@ee.doe.gov.

DOE also maintains a repository of frequently asked questions pertaining to additional guidance issued by DOE.

In addition, if it is ultimately determined that a VRF multi-split system configuration exists for which the critical parameter adjustment procedures will result in an inability to test the system or provide materially inaccurate performance results, manufacturers may petition DOE for a test procedure waiver under 10 CFR 431.401.

DOE's website houses frequently asked questions (FAQs) pertaining to the DOE Appliance Standards Program. The FAQ list is available at:

https://www.energy.gov/eere/buildings/appliance-standards-guidance-and-frequently-asked-questions-faqs,

or interested parties may submit a new question at:

https://www.energy.gov/eere/buildings/appliance-standards-guidance-and-frequently-asked-questions.

2. Adjustment of Alternate Critical Parameter Values

As described in section III.E.5 of this document, DOE proposed to clarify how, in the event that a manufacturer's certified critical parameter settings were invalidated through the CVP, alternate critical parameters would be determined and used as control inputs during DOE enforcement testing. 86 FR 70644, 70663 (Dec. 10, 2021). In the December 2021 VRF TP NOPR, DOE elaborated that in such a case, it may still be necessary to adjust the alternate critical parameter values in order to meet capacity tolerances and SHR limits for the IEER test. Accordingly, DOE proposed to include provisions at 10 CFR 429.134(s)(3)(iii)(B)(

) specifying that in the case of invalidated critical parameter values in which DOE determines alternate critical parameters, additional adjustments to the alternate critical parameters are allowed in order to comply with capacity and/or SHR requirements.

Id.

Specifically, DOE proposed to rely on the methods for adjustment of critical parameters in proposed section 5.2 of appendix D1 to subpart F of part 431 with two modifications.

Id.

First, DOE proposed that in such a case, references in section 5.2 of appendix D1 to critical parameter values certified in the STI would be replaced with references to alternate critical parameter values determined under the CVP. Second, DOE proposed to determine the maximum operating state of each critical parameter (referred to as CP

Max

in AHRI 1230-2021 and the proposed regulatory text) based on the maximum operating state observed during a CVP conducted at 100-percent cooling load conditions, instead of using the information certified to the STI for the 100-percent cooling load point.

Id.

AHRI commented that it supports DOE's proposal to use alternate critical parameters for IEER adjustments in the case of invalidated STI critical parameters, as this proposal clarifies how a test would be run in this situation. (AHRI, No. 12 at p. 6) Daikin commented that DOE's proposed adjustments to meet capacity requirements, if not provided by the manufacturer in the STI, is acceptable. (Daikin, No. 13 at p. 4) DOE did not receive any additional comments on this topic.

Based on the discussion presented in the December 2021 VRF TP NOPR and in the preceding paragraphs, DOE is adopting its proposals for section 5.2 of appendix D1 to subpart F of part 431 regarding adjustment of alternate critical parameter values.

G. Certification, Compliance, and Enforcement

1. Determination of Represented Values

a. Introduction

VRF multi-split systems are, by definition, split-system commercial package air conditioners and heat pumps that employ an outdoor unit(s) and multiple separate indoor fan coil units connected in a single refrigerant circuit. 10 CFR 431.92. VRF multi-split heat pumps can be configured as heat recovery systems, which allows for recovered energy from the indoor units operating in one mode (

e.g.,

cooling) to be transferred to one or more other indoor units operating in the other mode (

e.g.,

heating). This necessitates a heat recovery box that is installed between the outdoor unit and indoor units. Additionally, VRF multi-split systems are available with different refrigerant options and are sold with a wide variety of components, including many that can optionally be installed on or within the unit, both in the factory and in the field. Each optional component may or may not affect a model's measured efficiency when tested to the DOE test procedure adopted in this final rule.

In the December 2021 VRF TP NOPR, DOE proposed several items related to configuration of the unit under test and determination of represented values. These proposals included instructions on how to select indoor unit models (via reference of the tested combination requirements specified in section 6.2.1 of AHRI 1230-2021) and provisions specifying the different represented values that must be made for each indoor unit type within a basic model, as well as provisions for determination of represented values for basic models distributed in commerce with specific components, heat recovery components, and multiple refrigerants. 86 FR 70644, 70663-70665 (Dec. 10, 2021). These proposals and related stakeholder comments are discussed in paragraph III.G.1.b of this document.

In this final rule, DOE is providing additional discussion to help clarify the interplay between the previously proposed representation requirements, the proposed indoor unit tested combination requirements, and the proposed approach for specific components. The approach finalized by this rule is substantively the same as the corresponding proposals in the December 2021 VRF TP NOPR. The provisions adopted in this final rule and the justification for adopting these

provisions are described in greater detail in section III.G.1.c of this document.

b. NOPR Proposals and Comments

i. Tested Combination and Indoor Unit Combinations

In the December 2021 VRF TP NOPR, DOE made two proposals pertaining to represented values for different combinations of VRF indoor unit models. First, DOE proposed to reference the tested combination provisions from section 6.2.1 of AHRI 1230-2021 in the test procedure at appendix D1. 86 FR 70644, 70663 (Dec. 10, 2021). These provisions instruct how to select indoor unit models to comprise a ducted, non-ducted, or small-duct high-velocity tested combination. Section 6.2.1 also specifies an indoor unit selection hierarchy based on indoor unit sub-type and other design characteristics. For example, to compose a non-ducted tested combination, AHRI 1230-2021 specifies compact 4-way ceiling cassettes as the highest-priority selection and further requires that the indoor unit model having the lowest normalized coil volume and lowest-efficiency indoor fan motor within the specified indoor unit type must be selected. Second, DOE proposed that manufacturers must determine separate represented values for each indoor unit tested combination that is distributed in commerce. 86 FR 70644, 70664 (Dec. 10, 2021). Through this approach, each VRF basic model would be required to include separate representations for each of the ducted, non-ducted, and small-duct, high-velocity indoor unit tested combinations (if distributed in commerce in such a combination). DOE also proposed that manufacturers would be allowed to make optional “mixed” representations based on the simple average of represented values of any two tested combinations within a basic model.

Id.

In response, AHRI, Carrier, and Daikin commented that they support DOE's proposals for determining represented values for different indoor unit combinations/mixed combinations. (AHRI, No. 12 at p. 6; Carrier, No. 7 at p. 1; Daikin, No. 13 at p. 5). DOE did not receive any comments specially addressing its proposal to reference the tested combination provisions from section 6.2.1 of AHRI 1230-2021.

ii. Treatment of Specific Components

AHRI 1230-2021 outlines requirements for specific components in Appendix F, “Unit Configuration for Standard Efficiency Determination—Informative.” Appendix F provides discussion of components which would not be considered in representations, and provides instructions either to minimize their impact during testing or to determine representations for individual models with such components based on other individual models that do not include them. In the December 2021 VRF TP NOPR, instead of referencing Appendix F of AHRI 1230-2021, DOE tentatively determined that it was necessary to adopt similar instructions in a more comprehensive manner, so the Department proposed provisions in the appendix D1 test procedure, in the representation requirements at 10 CFR 429.43, and in the enforcement provisions at 10 CFR 429.134. 86 FR 70644, 70657 (Dec. 10, 2021).

Specifically, DOE proposed test provisions in section 6 of appendix D1 that instructed how to test a VRF multi-split system equipped with any specific component(s) listed in Table 6.1

of that same section. 86 FR 70644, 70686 (Dec. 10, 2021). These provisions were designed to minimize the impact on measured performance caused by testing with the specific component(s) present. Additionally, DOE proposed representation requirements in 10 CFR 429.43(a)(4) that explicitly allowed representations for individual models with certain components to be based on testing for individual models without those components; the proposal included a table in 10 CFR 429.43(a)(4)(i) listing the two components for which these provisions would apply (air economizers and desiccant dehumidification components). 86 FR 70644, 70657-70658 (Dec. 10, 2021). DOE also proposed corresponding product enforcement provisions in 10 CFR 429.134 indicating that DOE would conduct enforcement testing on VRF multi-split systems having individual indoor unit models that do not include air economizers or dehumidification components, except in certain circumstances. 86 FR 70644, 70658 (Dec. 10, 2021).

Table 6.1 includes test provisions for VRF multi-split systems equipped with desiccant dehumidification components, air economizers, fresh air dampers, hail guards, low ambient cooling dampers, power correction capacitors, and/or ventilation energy recovery systems (VERS). 86 FR 70644, 70686-70687 (Dec. 10, 2021).

DOE also proposed to adopt language more specific to VRF multi-split systems, as compared to the general language contained in section F2.4 of AHRI 1230-2021. Specifically, DOE proposed to use the term “individual indoor unit models” to account for potential discrepancies across individual indoor unit models that comprise the VRF multi-split system tested combination. 86 FR 70644, 70657 (Dec. 10, 2021). DOE's proposed approach would allow for the individual consideration of specific components on an indoor unit-by-indoor unit basis to account for scenarios in which individual indoor unit models in the tested combination differ in components.

For two components—coated coils and steam/hydronic heat coils—DOE did not propose to include these components in the list of specific components warranting enforcement relief (

i.e.,

provisions in 10 CFR 429.43(a)), nor did DOE propose any provisions to minimize their impact during testing (

i.e.,

provisions in appendix D1). DOE noted that coated coils and steam/hydronic heat coils were not included in the list of optional features in Section F2.4 of AHRI 1230-2021, and determined the industry consensus to be that coated coils and steam/hydronic heat options should not be treated as optional features for VRF multi-split systems and/or that VRF multi-split systems are not distributed in commerce with these features. 86 FR 70644, 70657 (Dec. 10, 2021).

Finally, DOE stated that, were DOE to adopt the provisions in appendix D1, 10 CFR 429.43, and 10 CFR 429.134 as proposed, DOE would rescind the Commercial HVAC Enforcement Policy to the extent it is applicable to VRF multi-split systems. 86 FR 70644, 70658 (Dec. 10, 2021).

In comments on the December 2021 VRF TP NOPR, Lennox, AHRI, and Carrier stated that they support DOE's proposal to include test provisions for specific components, as outlined in Table 6.1 of Appendix D1. (Lennox, No. 8 at p. 2; AHRI, No. 12 at p. 2; Carrier, No. 7 at p. 1) Further, AHRI encouraged DOE to specifically exclude VRF multi-split systems from the Commercial HVAC Enforcement Policy going forward so as to avoid confusion. (AHRI, No. 12 at p. 2) Daikin commented that coated coils, low ambient cooling dampers, and power correction capacitors are a part of the outdoor unit model and asserted that a clarification was needed at 10 CFR 429.43(a)(4) to designate both indoor and outdoor unit models, as opposed to just indoor unit models. (Daikin, No. 13 at p. 2)

With respect to DOE's proposals to exclude coated coils and steam/hydronic heat coils from the testing provisions and from consideration when determining represented values, Lennox, AHRI, and Daikin all commented that DOE should also consider including coated coils and

steam/hydronic heat coils in table 6.1, as contained in the DOE Commercial HVAC Enforcement Policy. (Lennox, No. 8 at p. 2; AHRI, No. 12 at p. 2; Daikin, No. 13 at p. 2) AHRI asserted that coated coils should not be required for testing because units will always be available without them (

i.e.,

represented values should not be required to be based on a VRF multi-split system with coated coils when there would always be an otherwise comparable model available without coated coils). (AHRI, No. 12 at p. 2) Daikin stated that adding steam/hydronic coils to table 6.1 would align regulations for VRF multi-split systems with those for other equipment categories, and that coated coils, low ambient cooling dampers, and power correction capacitors might be included in the outdoor section of VRF multi-split systems. (Daikin, No. 13 at p. 2)

In response, DOE has considered these comments and has determined that clarifications are warranted to the approach proposed in the December 2021 VRF TP NOPR regarding the treatment of certain components for determining represented values. Therefore, DOE is adopting the proposals made in the December 2021 VRF TP NOPR, with clarifications that are discussed in detail in section III.G.1.c of this final rule.

iii. Heat Recovery Components

Section 5.6 of AHRI 1230-2021 specifies that for all VRF heat recovery systems, the heat recovery control unit must be attached during all tests. Similarly, section F2.3 of AHRI 1230-2021 requires that all heat recovery components must be present and installed for testing individual models distributed in commerce with these components. DOE proposed in the December 2021 VRF TP NOPR to reference Section 5.6 of AHRI 1230-2021 in its proposed test procedures for VRF multi-split systems at appendix D1. 86 FR 70644, 70651 (Dec. 10, 2021). Consistent with section F2.3 of AHRI 1230-2021, DOE also proposed to specify in 10 CFR 429.43(a) that for basic models of VRF multi-split systems distributed in commerce with heat recovery components, the manufacturer must determine represented values for the basic model based on performance of an individual model distributed in commerce with heat recovery components. 86 FR 70644, 70656 (Dec. 10, 2021).

DOE did not receive any comments regarding heat recovery components in response to the December 2021 VRF TP NOPR. In this final rule, DOE is finalizing its proposed test provisions in appendix D1 but is removing its proposal to specify in 10 CFR 429.43(a) that VRF multi-split systems distributed in commerce with heat recovery components must determine represented value based on a configuration of the basic model with heat recovery components installed, as discussed in section III.G.1.c.ii of this final rule.

iv. Multiple Refrigerants

DOE proposed in the December 2021 VRF TP NOPR that in cases in which a basic model of VRF multi-split system can be used with multiple refrigerants without requiring different hardware, then a manufacturer must determine the represented values (

e.g.,

IEER, COP, and cooling capacity) for that basic model based on the refrigerant(s)—among all refrigerants listed on the unit's nameplate—that result in the lowest cooling efficiency. 86 FR 70644, 70665 (Dec. 10, 2021). DOE also clarified that, should the use of a different refrigerant require different hardware, this would represent a different basic model and, consequently, separate representations of energy efficiency would be required.

Id.

The Joint Advocates, Lennox, and the CA IOUs expressed support for DOE's proposal to use the refrigerant listed on the unit's nameplate that results in the lowest cooling efficiency for represented values. (Joint Advocates, No. 9 at p. 1; Lennox, No. 8 at p. 3; CA IOUs, No. 11 at p. 4) The Joint Advocates commented that DOE's proposal would ensure that when manufacturers test a basic model, a refrigerant would not be selected that overstates the efficiency of the equipment as compared to if it were charged with another (less-efficient) refrigerant in the field. (Joint Advocates, No. 9 at p. 1) The Joint Advocates and the CA IOUs recommended allowing manufacturers to make additional representations for a basic model using different (

i.e.,

more-efficient) refrigerants to demonstrate the benefits of using more-efficient refrigerants. (Joint Advocates, No. 9 at p. 1; CA IOUs, No. 11 at p. 4)

DOE has considered these comments and has determined that the multiple refrigerant proposals made in the December 2021 VRF TP NOPR are not needed because the approach for determining represented values adopted in this final rule addresses the issue consistent with the NOPR proposals without need to specifically address multiple refrigerants. This matter is discussed in greater detail in section III.G.1.c of this final rule.

c. Final Rule Approach

i. Summary

As previously introduced, DOE is finalizing an approach for determining represented values that improves the clarity of, but is not substantively different than, the proposals in the December 2021 VRF TP NOPR. In this final rule, DOE is amending language in 10 CFR 429.43(a)(3)(ii) to clarify the interplay between the indoor unit tested combination, the representation requirements pertaining to specific components, and general requirements pertaining to represented values. DOE has structured the provisions at 10 CFR 429.43(a)(3)(ii) to reflect the different considerations when selecting outdoor vs. indoor units, and to highlight that the specific components currently subject to DOE enforcement relief (

i.e.,

desiccant dehumidification components and air economizers) are only applicable at the level of indoor units within a tested combination, not at the basic model level. DOE is specifying that for each indoor unit combination within a basic model (

i.e.,

ducted, non-ducted, or SDHV), the representation must be based on a combination of: (1) the least-efficient outdoor unit model distributed in commerce for that particular basic model which would be based on the least-efficient refrigerant (as discussed in section III.G.1.c.ii of this document); and (2) the combination of indoor units selected in accordance with the criteria described in section III.G.1.c.iii of this document. By taking this approach, DOE is clarifying the interaction between long-standing basic model provisions, tested combination requirements, and the treatment of specific components for VRF multi-split systems.

ii. Outdoor Unit and Heat Recovery

In this final rule DOE is: (1) clarifying that the least-efficient outdoor unit model within a basic model must be used for determining represented values; and (2) clarifying that the test procedure requires that VRF multi-split heat pumps with heat recovery must be tested with heat recovery components present, but without the need for representation requirements as initially proposed. DOE is not adopting any exemptions to the “least-efficient” requirement for outdoor unit(s) used to determine represented values because neither of the specific components listed in Table 2 to 10 CFR 429.43(a)(3)(ii)(B) (

i.e.,

air economizers and desiccant dehumidification components—as adopted in this final rule) are applicable for VRF outdoor units.

With respect to comments received regarding multiple refrigerants available for a basic model of VRF multi-split system, because the efficiency of the VRF multi-split system could be impacted by different refrigerant choices, the least-efficient outdoor model requirement necessitates consideration of the least-efficient refrigerant when determining represented values for that basic model. Upon further consideration, DOE has determined that the proposal in the December 2021 VRF TP NOPR regarding multiple refrigerants is already included substantively in the provision adopted at 10 CFR 429.43(a)(3) regarding least-efficient outdoor units, and that additional provisions would be redundant. As such, in this final rule, DOE is not adopting the refrigerant-specific language at 10 CFR 429.43(a)(3) that was proposed in the December 2021 NOPR.

Regarding heat recovery components, as described in section III.G.1.b.iv of this document, DOE proposed related testing provisions in appendix D1 and representation provisions in 10 CFR 429.43(a). In this final rule, DOE is finalizing its proposed test provisions in appendix D1 but is removing its proposal to specify in 10 CFR 429.43(a) that VRF multi-split systems distributed in commerce with heat recovery components must determine represented value based on a configuration of the basic model with heat recovery components installed. Upon further review of the test provisions referencing section 5.6 of AHRI 1230-2021, DOE has determined that all VRF multi-split heat pumps with heat recovery capability would always be required by to be configured with heat recovery components installed. Further, DOE's energy conservation standards for VRF multi-split systems specified at 10 CFR 431.97 classify systems with and without heat recovery to be in different equipment classes, such that a given VRF basic model does not contain systems with and without heat recovery (as such systems are certified under separate equipment classes).

The combination of these provisions ensures that represented values for VRF multi-split heat pumps with heat recovery are always determined with heat recovery components installed. Therefore, DOE finds its earlier proposal to be unnecessary, and accordingly, the Department is not adopting represented value provisions related to heat recovery components in this final rule.

DOE distinguishes certain VRF equipment classes by “with heat recovery” and “without heat recovery”, and other equipment classes with “no heating or electric resistance heating” and “all other types of heating.” Footnote 1 to Table 13 to 10 CFR 431.97 specifies that VRF systems with heat recovery fall under the category of “all other types of heating” unless they also have electric resistance heating. In the March 2022 VRF ECS NOPR, DOE proposed to amend 10 CFR 431.97 to adopt the equipment class structure found in ASHRAE Standard 90.1-2016 for VRF multi-split systems, which, if adopted would create separate equipment classes for VRF heat pumps with and without heat recovery for all capacity ranges and heat rejection media (

i.e.,

replacing any class distinctions based on supplementary heating type). 87 FR 11335, 11346 (March 1, 2022).

iii. Indoor Unit Specification

DOE made several proposals in the December 2021 VRF TP NOPR pertaining to the selection of indoor unit models when determining represented values for the basic model of VRF multi-split system. 86 FR 70644, 70664-70665 (Dec. 10, 2021). As discussed elsewhere in this document, DOE proposed provisions related to different tested combinations of indoor units (see section III.G.1.b.i of this document), certification reporting requirements (see section III.G.2 of this document), and provisions related to treatment of specific components (see section III.G.1.b.ii of this document).

As described in section III.G.1.b.i of this document, DOE received only supportive comments in response to its proposals for determining represented values for different indoor unit tested combinations (

i.e.,

ducted, non-ducted, SDHV, and mixed representations thereof). In light of these comments and the reasoning provided in the December 2021 VRF TP NOPR, DOE is adopting its earlier proposals pertaining to this topic in this final rule.

The adopted provisions provide guidance for determining required represented values of indoor unit combinations (

i.e.,

ducted, non-ducted, SDHV) and provide guidance for determining optional mixed representations that are determined by taking a simple average of any two of the required representations. By adopting these provisions, each VRF outdoor unit may include up to six separate representations within the same basic model number.

Regarding certification requirements, as discussed in greater detail in section III.G.2 of this document, DOE proposed to require that manufacturers publicly report the indoor unit combination (

i.e.,

ducted, non-ducted, SDHV, or mixed) used to determine represented values, as well as all outdoor and indoor unit model numbers used to compose the tested combination. For the reasons discussed in the December 2021 VRF TP NOPR and in section III.G.2.a of this document, DOE is adopting these amended certification requirements as proposed. DOE also proposed to require that manufacturers supply information in their STI regarding whether specific components were present or absent when determining represented values for the basic model. As discussed in section III.G.2.b of this document, DOE is not adopting certification requirements related to specific components in this final rule.

Regarding specific components, DOE is clarifying the provisions at 10 CFR 429.43(a)(3) that cover the determination of represented values for VRF multi-split systems. In the December 2021 VRF TP NOPR, DOE proposed to individually consider specific components on an indoor-unit-by-indoor unit basis when determining represented values. 86 FR 70644, 70657 (Dec. 10, 2021). DOE's approach in this final rule is consistent with the approach in the NOPR in that it requires consideration of specific components for each indoor unit individually, rather than at the basic model level. DOE has also introduced the concept of “fully-specified” indoor unit model numbers in order to provide greater clarity about selection of indoor units and to explicitly tie these requirements to the aforementioned certification requirements.

For cases where an indoor unit model number is fully specified in the public certification (

i.e.,

the indoor unit model number includes sufficient information to identify the presence or absence of all components), DOE will require that the indoor unit model number, precisely as it appears as certified, shall be used for determining represented values. For example, for an indoor unit whose certified model number affirmatively designates the presence of dehumidification components, represented values must be determined based on the indoor unit model with dehumidification components installed, regardless of whether otherwise comparable indoor units are distributed in commerce without dehumidification components present. This approach does not conflict with the tested combination requirements in section 6.2 of AHRI 1230-2021, which sets minimum criteria for indoor model specification and does not disallow further specification (including specification of dehumidification components and/or air economizers).

For cases where an indoor unit model number is not fully-specified as part of the certified tested combination (

i.e.,

where the model number is constructed in such a way that does not fully specify

the absence or presence of all components), DOE is applying the represented value requirements as proposed in the NOPR. This approach requires that for indoor unit model numbers that are not fully-specified in the certification, a fully-specified indoor unit must be selected to determine represented values for the basic model. This fully-specified indoor model number must be consistent with the certified indoor unit model number (

i.e.,

all specified digits must match), and, among the group of all indoor unit models having a consistent model number, must have the least number (which may include zero) of specific components (

i.e.,

air economizers and desiccant dehumidification components) installed.

Regarding DOE's proposed testing provisions for specific components in 10 CFR 431, subpart F, appendix D1, DOE is adopting the proposals from the December 2021 VRF TP NOPR. Specifically, DOE is finalizing provisions in section 6 to appendix D1 that provide instruction how to test a VRF multi-split system equipped with any specific component(s) listed in Table 6.1

of that same section.

As discussed, DOE received comments suggesting that DOE should consider including coated coils and steam/hydronic heat coils in the list of specific components in table 6.1 to appendix D1. DOE also received similar comments pertaining to coated coils in response to other commercial HVAC equipment test procedure NOPRs, specifically the test procedure supplemental notice of proposed rulemaking (“SNOPR”) published for direct expansion-dedicated outdoor air systems (“DX-DOASes”)

(Docket No. EERE-2017-BT-TP-0018, AHRI, No. 34 at p. 4). In response to the DX-DOAS SNOPR, AHRI and Madison Indoor Air Quality (“MIAQ”) asserted that some coated coils impact performance, but that each coating is different (Docket No. EERE-2017-BT-TP-0018, AHRI, No. 34 at p. 4; MIAQ, No. 29 at p. 4).

See

86 FR 72874 (Dec. 23, 2021).

AHRI and MIAQ's assertion that some coated coils do impact energy use suggests that there are other implementations of coated coils that do not impact energy consumption as measured by the adopted test procedure (

i.e.,

the implementation of coated coils does not necessarily or inherently impact energy use). DOE has no data indicating the range of impacts for those coatings that do affect energy use, or how other characteristics of the coatings, such as durability and cost, correlate with energy use impacts. Absent such data, DOE is unable to determine the specific range of impacts on energy use made by coated coils. Nevertheless, given that comments on the DX-DOAS SNOPR suggest that certain implementations of coated coils do not impact energy use, DOE has determined that for those units for which coated coils do impact energy use, representations should include those impacts, thereby providing full disclosure for commercial customers. Consequently, DOE is not incorporating coated coils into DOE's provisions specified in 10 CFR 429.43(a)(3) which allow for the exclusion of specified components when determining represented values for VRF multi-split systems. This approach is consistent with the one DOE has established in a final rule for the DX-DOAS test procedure. 87 FR 45164, 45186 (July 27, 2022).

Commenters did not indicate whether models are available with steam/hydronic heat, thereby supporting DOE's tentative conclusion in the December 2021 VRF TP NOPR that steam/hydronic heat components are not present in VRF multi-split systems and/or models with these components are not distributed in commerce. 86 FR 70644, 70657 (Dec. 10, 2021). Consequently, DOE is finalizing its proposal to exclude steam/hydronic heat from the specific components list for VRF multi-split systems in 10 CFR 429.43(a)(3).

As proposed in the December 2021 VRF TP NOPR, DOE sought to address VRF multi-split systems that include the specified excluded components both in the requirements for representation (

i.e.,

10 CFR 429.43) and as part of the equipment specific enforcement provisions for assessing compliance (

i.e.,

10 CFR 429.143). 86 FR 70644, 70656-70658 (Dec. 10, 2021). Instruction on which units to test for the purpose of representations are addressed in 10 CFR 429.43. DOE has determined that including parallel enforcement provisions in 10 CFR 429.134 would be redundant and potentially cause confusion, because DOE would select for enforcement only those individual models that are the basis for making basic model representations as specified in 10 CFR 429.43. Therefore, in this final rule, DOE is providing the requirements for making representations of VRF multi-split systems that include the specified components in 10 CFR 429.43, and is not including parallel direction in the enforcement provisions of 10 CFR 429.134 established in this final rule. However, DOE is finalizing the provision that allows enforcement testing of alternative individual models with specific components, if DOE cannot obtain for test the individual models without the components that are the basis of the representation.

In regards to the NOPR proposal that DOE shall rescind the commercial HVAC enforcement policy for VRF multi-split systems, DOE has provided substantive guidance for each component included in both the DOE Enforcement Policy and the “Equipment Features Requiring Test Procedure Action” from the term sheet agreed upon by an ASRAC working group for certain commercial HVAC equipment (“Commercial HVAC CCE Term Sheet”).

(EERE-2013-BT-NOC-0023-0052) Consequently, these documents would no longer be applicable to VRF multi-split systems and could potentially cause confusion. To prevent this confusion, DOE is clarifying in this final rule that the provisions established in this final rule will take precedence over those in the DOE Enforcement Policy and the Commercial HVAC CCE Term Sheet, and that the aforementioned documents will no longer be applicable to VRF multi-split systems. As previously discussed, this change will not take effect until the compliance date of amended energy conservation standards for VRF multi-split systems denominated in terms of IEER, should DOE adopt such standards.

In 2013, members of ASRAC formed the Commercial HVAC Working Group to engage in a negotiated rulemaking effort regarding the certification of certain commercial HVAC equipment, including VRF multi-split systems. The Commercial HVAC Working Group's recommendations are available at

www.regulations.gov

under Docket No. EERE-2013-BT-NOC-0023-0052.

2. Certification Reporting Requirements

a. Certification Requirements

DOE specifies certification reporting requirements for VRF multi-split systems in 10 CFR 429.43(b). Certification reporting requirements for VRF multi-split systems include both public equipment-specific information and STI. As previously described, in the December 2021 VRF TP NOPR DOE proposed to amend the certification reporting requirements for VRF multi-split systems to address the IEER metric but did not propose amendments to the current standards (in terms of EER). 86 FR 70644, 70665 (Dec. 10, 2021). Subsequently, in the March 2022 VRF ECS NOPR DOE proposed to amend

standards for VRF multi-split systems to be in terms of the IEER cooling metric, with a proposed compliance date of January 1, 2024. 87 FR 11335, 11349 (March 1, 2022). Therefore, the amended certification reporting requirement proposals would only apply when certifying to a future IEER standard; existing certification reporting requirements used when certifying to the current EER standards would not change. In the December 2021 VRF TP NOPR, DOE proposed to add the following items to the public certification reporting requirements for VRF multi-split systems:

• IEER values (replacing the current certification requirement for EER values);

• The rated heating capacity, in Btu/h;

• The indoor unit combination used to determine the represented values for an individual combination (

i.e.,

a non-ducted, ducted, SDHV, or mixed indoor unit combination), and all outdoor and indoor unit model numbers used to compose the tested combination; and

• The refrigerant used to determine the represented values for a basic model (

e.g.,

EER, IEER, COP, and cooling capacity).

86 FR 70644, 70665 (Dec. 10, 2021). A draft certification template reflecting the proposed changes has been included in the docket.

The draft certification template columns can be found in the docket at:

www.regulations.gov/document/EERE-2021-BT-TP-0019-0001.

In response to DOE's certification proposals, the Joint Advocates commented that they support DOE's proposal to publicly report the heating capacity for VRF multi-split systems, stating that this requirement aligns with reporting requirements for the cooling metric and that consumers would be interested in this information. (Joint Advocates, No. 9 at p. 1) The CA IOUs supported DOE's certification proposals but requested that the certification report should clarify that COP is measured per the “high temperature” heating test at 47 °F, to prevent confusion with other temperatures at which heating COP tests can be conducted. As introduced in section III.G.1.b.v of this document, the CA IOUs also recommended allowing manufacturers to make additional representations for a basic model using different (

i.e.,

more-efficient) refrigerants. (CA IOUs, No. 11 at p. 3) The CA IOUs suggested a corresponding certification requirement that the global warming potential (GWP) of each refrigerant be listed along with the performance information. (CA IOUs, No. 11 at p. 4)

With respect to the CA IOUs' comment requesting clarification of the COP heating condition in the certification report, as discussed in section III.D.2 of this document, DOE acknowledges the need to clarify that the ratings for heating mode tests of air-cooled VRF multi-split heat pumps used for compliance with standards are those referred to as “High Temperature Steady-state Test for Heating” in AHRI 1230-2021 and measured at 47 °F outdoor ambient air temperature. Additionally, DOE acknowledges the need to clarify that the ratings for heating mode tests of water-source VRF multi-split heat pumps used for compliance with standards are those specified for “Water Loop Heat Pumps” in AHRI 1230-2021 and measured at 68 °F entering liquid temperature. Consistent with the test procedure provisions adopted in this final rule (as discussed in section III.D.2 of this document) and the CA IOUs' suggestion, DOE is amending the certification template to read “Coefficient of Performance, measured at 47 °F for air-source VRF multi-split heat pumps or measured at 68 °F Entering Water Temperature for water-source VRF multi-split heat pumps.”

With respect to the CA IOU's comments regarding certification requirements for VRF multi-split systems available with multiple refrigerants, DOE has concluded that because the efficiency of the VRF multi-split system could be impacted by different refrigerant choices, the least-efficient outdoor model requirement necessitates consideration of the least-efficient refrigerant when determining represented values for that basic model (see discussion in III.G.1.c.ii of this document). In this final rule, DOE is also finalizing its proposal to require certification of the refrigerant used to determine the represented values for a basic model. By combining these provisions, a set of represented values will be determined for a given basic model based on the least-efficient outdoor unit (and, therefore, as discussed, the least-efficient refrigerant), and the refrigerant must be certified by the manufacturer. Therefore, DOE is not adopting the CA IOUs' suggestions to allow certification of multiple refrigerants, because it would be inconsistent with the Department's adopted requirement that the represented values for a basic model be based on the least-efficient outdoor unit. Correspondingly, because DOE is not adopting the CA IOU's suggestion to allow certification of multiple refrigerants, DOE has concluded that requiring certification of the associated refrigerant characteristics (

i.e.,

GWP) would provide minimal benefit, as there will not be ratings for different refrigerants within a basic model to compare. Therefore, DOE has concluded that requiring certification of refrigerant GWP would be unnecessarily burdensome.

DOE is adopting all other proposals related to certification reporting requirements, without change. As discussed, these amended certification reporting requirements are not required until the compliance date of amended energy conservation standards for VRF multi-split systems denominated in terms of IEER, should DOE adopt such standards.

b. Supplemental Testing Instructions

The December 2021 VRF TP NOPR included proposals to amend the STI provisions at 10 CFR 429.43(b)(4) to reflect the proposed amendments to the test procedure and the proposed adoption of the IEER metric. 86 FR 70644, 70666 (Dec. 10, 2021). DOE proposed amendments and additions to the STI requirements as follows:

• Identification of the indoor units to be thermally active for each IEER test point;

• The rated indoor airflow for the full-load cooling, full-load heating, and all part-load cooling tests (for each indoor unit), in standard cubic feet per minute (scfm);

• The indoor airflow-control setting to be used in the full-load cooling test and the indoor airflow control setting to be used in the full-load heating test (for each indoor unit);

• For water-cooled units, the rated water flow rate in gallons per minute (gpm);

• System start-up or initialization procedures, including conditions and durations;

• The duration of the compressor break-in period. (Existing requirements in 10 CFR 431.96(c) require manufacturers to include this information in the test data underlying the certified ratings that must be maintained according to 10 CFR 429.71);

• Instructions for adjustment of critical parameters to meet capacity targets and/or SHR limits, including hierarchy for adjusting;

• The layout of the system set-up for testing (previously required upon request) including a piping diagram, set-up instructions for indoor units and outdoor units, charging instructions, a control wiring diagram, and

identification of the location of each critical parameter;

• Explicitly providing that the nominal cooling capacity and nominal heating capacity (if applicable) in British thermal units per hour (Btu/h) must be certified for each outdoor unit and indoor unit;

• Requiring testing instructions for conducting testing for all indoor unit combinations with distinct represented values within a basic model, as applicable;

• Removing the current requirement to report compressor frequency setpoints and instead require reporting operational settings for all critical parameters to be manually controlled for each of the four IEER cooling test conditions and for the COP heating test;

• Removing the reporting requirement regarding whether the model will operate at test conditions without manufacturer programming because the VRF enforcement provisions allow for a manufacturer representative to be on site for DOE testing;

• Removing the reporting requirement for rated static pressure, which is unnecessary because AHRI 1230-2021 includes ESP requirements for testing; and

• The frequency of oil-recovery cycles.

Further, in the December 2021 VRF TP NOPR, DOE proposed at 10 CFR 429.43(b)(4) a certification reporting requirement for supplemental test instructions for VRF multi-split systems regarding specific components, corresponding to the proposed representation requirements for specific components at 10 CFR 429.43(a)(4). Specifically, DOE proposed that the manufacturer must certify in the STI for which, if any, specific components (as listed in 10 CFR 429.43(a)(4)(i)) the following provisions are applicable: (1) the indoor unit model(s) in a tested combination within a basic model include both individual indoor unit models distributed in commerce with the specific component and individual indoor unit models distributed in commerce without the specific component; (2) at least one of the individual indoor unit models distributed in commerce without the specific component is otherwise identical to any given individual indoor unit model distributed in commerce with the specific component; and (3) represented values for the tested combination are based on performance of individual indoor unit models distributed in commerce without the specific component. 86 FR 70644, 70666-70667 (Dec. 10, 2021). These proposed provisions would require manufacturers to report whether the represented values for that VRF multi-split system basic model were determined based on the presence or absence of air economizers and/or desiccant dehumidification components.

In commenting on DOE's proposals in this area, AHRI and Carrier stated that STI requirements may need to include provisions that specify which, if any, components were used when calculating efficiency ratings. (AHRI, No. 12 at p. 2; Carrier, No. 7 at p. 1)

In response and as described in section III.G.1.c.iii of this document, DOE is finalizing an approach in this rule requiring that if an indoor unit model number is not fully specified in the public certification, then represented values must be determined from a fully-specified individual indoor unit model distributed in commerce that must be consistent with the certified indoor unit model number (

i.e.,

all specified digits must match). Among the group of all indoor unit models having a consistent model number, that VRF system must have the least number (which may include zero) of specific components installed. Because the representation requirements adopted in this final rule provide clear direction as to how to determine represented values for basic models that include specific components, DOE concludes that a certification requirement for manufacturers to report whether representations are based on model(s) with specific components installed would be duplicative and would impose unnecessary burden on manufacturers. Therefore, DOE is not adopting any certification requirements related to specific components in this final rule.

DOE also proposed to require reporting as part of the STI the following manufacturer-specified input conditions for conducting a CVP at each of the four IEER cooling test conditions:

□ The required thermostat setpoints to ensure control for 80 °F dry-bulb temperature when accounting for setpoint bias;

□ The starting indoor dry-bulb temperature; and

□ The indoor dry-bulb temperature ramp rate.

Id.

The CA IOUs commented that the system controls setting for steady-state tests should be included in the STI requirements. Specifically, the CA IOUs suggested expanding the requirement for the “required dip switch/control settings for step or variable components” to instead require “Dip switch/Control Settings from the manufacturer's installation instructions used for the full-load cooling and full-load heating tests.” The CA IOUs asserted that this change would reduce the test burden when determining which control setting to use for the CVP as part of enforcement testing. (CA IOUs, No. 11 at p. 4) AHRI commented that some certification reporting requirements, such as compressor speed, critical parameter settings, and system device required for testing, are confidential business information and that they should be designated as such for certification. AHRI elaborated on this point by stating that the information included in the STI is confidential and should be designated as such. (AHRI, No. 12 at pp. 6-7) Similarly, Daikin commented that they support DOE's proposal for certification reporting requirements, provided that all confidential information may be submitted in the STI, because the STI is not available to the public. (Daikin, No. 13 at p. 5)

With respect to the CA IOU's request to amend the language of STI reporting requirements for dip switch/control settings, DOE interprets this suggestion to mean that manufacturers would be required to specify all dip switch/control settings required for conducting the full-load cooling and heating tests. This would include all settings for “step or variable components” in addition to any other settings required for testing that are not otherwise dictated by the test procedure but may impact system behavior—for example, “mode-type” settings (

e.g.,

eco-mode) or settings related to another function (

e.g.,

noise reduction settings). DOE finds that the CA IOUs' proposal would improve the clarity of existing certification requirements, as it would ensure that the control settings needed for testing are readily identifiable and that they are used in a consistent manner during testing. Further, DOE finds that the CA IOUs' suggestion would not require additional collection of information by manufacturers, because the settings used for conducting testing would be readily available to manufacturers. Therefore, DOE is adopting the STI certification requirements for VRF multi-split systems as proposed in the December 2021 VRF TP NOPR, with the clarification that certification of dip switch/control settings applies more broadly than just step/variable components. As discussed previously, these amended STI certification requirements are not required until the compliance date of amended energy conservation standards denominated in

terms of IEER, should DOE adopt such standards.

With respect to AHRI and Daikin's comments, DOE notes that certification reports routinely include both public and non-public information. Specifically, 10 CFR 429.43(b)(2) specifies requirements for public equipment-specific information, and 10 CFR 429.43(b)(3) and (4) specify requirements for equipment-specific information and supplemental information that are non-public. DOE notes that the treatment of confidential business information is addressed pursuant to the regulations at 10 CFR 1004.11. Any person submitting information that they believe to be confidential and exempt by law from public disclosure should submit via two well-marked copies: one copy of the document marked “confidential” including all the information believed to be confidential, and one copy of the document marked “non-confidential” with the information believed to be confidential deleted. While DOE is responsible for making the final determination with regard to the disclosure or nondisclosure of information contained in requested documents, DOE will consider the submitter's views in making its determination. 10 CFR 1004.11(a). Accordingly, in light of the existing framework for handling confidential business information, DOE does not find it necessary to adopt the additional measures suggested by AHRI and Daikin. For the reasons stated in the December 2021 VRF TP NOPR and the paragraphs here, DOE is adopting its proposed amendments related to the supplemental testing instructions for VRF multi-split systems along with the previously discussed modifications suggested by the CA IOUs.

3. Models Required for AEDM Validation

In the December 2021 VRF TP NOPR, DOE proposed that the manufacturer must validate an AEDM used to make representations for only a single type of indoor unit combination (

i.e.,

ducted, non-ducted, or SDHV indoor unit combinations) within or across all its basic models by testing at least a single tested combination of that type of indoor unit combination for each of the two selected basic models. 86 FR 70644, 70667 (Dec. 10, 2021). If a manufacturer makes representations for two types of indoor unit combinations (

i.e.,

ducted, non-ducted, and/or SDHV indoor unit combinations) within or across all its basic models to which the AEDM applies, DOE proposed that the manufacturer must test at least: (1) a single tested combination of a selected basic model as the first of those two types of indoor unit combination, and (2) a single tested combination of a different selected basic model as the second of those two types of indoor unit combination.

Id.

If a manufacturer makes representations for all three types of indoor unit combinations (

i.e.,

ducted, non-ducted, and SDHV indoor unit combinations) within or across all its basic models to which the AEDM applies, DOE proposed that the manufacturer must test at least a single tested combination of a selected basic model as a non-ducted tested combination and a single tested combination of a different selected basic model as a ducted tested combination.

Id.

In response, AHRI and Daikin commented in support of DOE's proposal to amend the applicable requirements for AEDM validation. (AHRI, No. 12 at p. 7; Daikin, No. 13 at p. 5) DOE received no other comments on its AEDM proposals.

Accordingly, DOE is finalizing its proposed AEDM validation requirements for VRF multi-split systems in 10 CFR 429.43(a)(2) and 10 CFR 429.70 to be similar to the sampling plan requirements for tested units, as discussed in section III.G.7 of this final rule. Furthermore, DOE has concluded that these AEDM validation requirements are consistent with AHRI 1230-2021, because they ensure the values developed with an AEDM conform to the results obtained using AHRI 1230-2021.

4. Manufacturer Involvement

a. Role of Manufacturer Representative

In light of the complexity of VRF multi-split systems, the DOE test procedure at 10 CFR 431.96(f) does allow for limited manufacturer involvement, specifying that a manufacturer's representative is allowed to witness assessment and/or enforcement testing, inspect and discuss set-up only with a DOE representative, and adjust only the modulating components in the presence of a DOE representative that are necessary to achieve steady-state operation. In the December 2021 VRF TP NOPR, DOE proposed to establish new provisions for manufacturer involvement as part of the product-specific enforcement provisions at 10 CFR 429.134(s)(2). 86 FR 70644, 70667 (Dec. 10, 2021). The proposals largely align with Sections 5.1.2 and 6.3.3 of AHRI 1230-2021 but prescribe more precisely the actions that a manufacturer's representative may take. Specifically, DOE proposed that a manufacturer's representative is allowed to support commissioning of the VRF multi-split system and to witness DOE assessment or enforcement testing.

at 86 FR 70667-70668. For all cooling and heating tests, DOE proposed that all control settings other than critical parameters must be set by a member of the third-party laboratory, and that a manufacturer's representative may initially set all critical parameters to their certified values.

Id.

at 86 FR 70668. For IEER cooling tests only, DOE proposed to specify that if additional adjustments to critical parameters are required for meeting capacity targets and/or SHR limits, a manufacturer's representative may make such adjustments in accordance with section 5.1 of appendix D1 using a proprietary control tool.

Id.

DOE further proposed that initial setting and any additional critical parameter adjustments performed by a manufacturer's representative during IEER testing must be monitored by third-party laboratory personnel using a service tool.

Id.

For the heating test, DOE proposed that the manufacturer's representative would not be permitted to make any critical parameter adjustments during testing and would only be allowed to initially set critical parameters to their certified values.

Id.

The CA IOUs, Joint Advocates, and Lennox commented that they support DOE's proposal to specify the parameters of manufacturer involvement during testing. (CA I

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