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Proposed Rule2021-26288

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

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Published

December 10, 2021

Issuing agencies

Energy Department

Abstract

The U.S. Department of Energy ("DOE") proposes to amend the test procedure for variable refrigerant flow multi-split air conditioners and heat pumps ("VRF multi-split systems") to incorporate by reference the latest version of the industry test standard. DOE also proposes to adopt the integrated energy efficiency ratio metric in its test procedures for VRF multi-split systems. Additionally, DOE proposes to adopt provisions in the updated industry test procedure relevant to certification and enforcement, including a controls verification procedure. DOE welcomes written comment from the public on any subject within the scope of this document (including topics not specifically raised in this proposal), as well as the submission of data and other relevant information.

Full Text

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[Federal Register Volume 86, Number 235 (Friday, December 10, 2021)]
[Proposed Rules]
[Pages 70644-70687]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-26288]

[[Page 70643]]

Vol. 86

Friday,

No. 235

December 10, 2021

Part III

Department of Energy

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10 CFR Parts 429 and 431

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

Federal Register / Vol. 86 , No. 235 / Friday, December 10, 2021 /
Proposed Rules

[[Page 70644]]

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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: Notice of proposed rulemaking and request for comment.

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SUMMARY: The U.S. Department of Energy (``DOE'') proposes to amend the
test procedure for variable refrigerant flow multi-split air
conditioners and heat pumps (``VRF multi-split systems'') to
incorporate by reference the latest version of the industry test
standard. DOE also proposes to adopt the integrated energy efficiency
ratio metric in its test procedures for VRF multi-split systems.
Additionally, DOE proposes to adopt provisions in the updated industry
test procedure relevant to certification and enforcement, including a
controls verification procedure. DOE welcomes written comment from the
public on any subject within the scope of this document (including
topics not specifically raised in this proposal), as well as the
submission of data and other relevant information.

DATES:
Comments: DOE will accept written comments, data, and information
regarding this notice of proposed rulemaking (NOPR) on or before
February 8, 2022. See section V, ``Public Participation,'' for details.
Meeting: DOE will hold a webinar on Thursday, January 20, 2022,
from 1:00 p.m. to 4:00 p.m. See section V, ``Public Participation,''
for webinar registration information, participant instructions, and
information about the capabilities available to webinar participants.

ADDRESSES: Interested persons are encouraged to submit comments using
the Federal eRulemaking Portal at <a href="http://www.regulations.gov">www.regulations.gov</a>. Follow the
instructions for submitting comments.
Alternatively, interested persons may submit comments, identified
by docket number EERE-2021-BT-TP-0019, by any of the following methods:
1. Federal eRulemaking Portal: <a href="http://www.regulations.gov">www.regulations.gov</a>.
2. Email: to <a href="/cdn-cgi/l/email-protection#267074606b534a524f55564a4f5267656e761416141772761616171f6643430842494308414950">[email&#160;protected]</a>. Include docket
number EERE-2021-BT-TP-0019 in the subject line of the message. No
telefacsimiles (``faxes'') will be accepted. For detailed instructions
on submitting comments and additional information on this process, see
section V of this document ``Public Participation.''
Although DOE has routinely accepted public comment submissions
through a variety of mechanisms, including the Federal eRulemaking
Portal, email, postal mail or hand delivery/courier, the Department has
found it necessary to make temporary modifications to the comment
submission process in light of the ongoing corona virus 2019 (COVID-19)
pandemic. DOE is currently suspending receipt of public comments via
postal mail and hand delivery/courier. If a commenter finds that this
change poses an undue hardship, please contact Appliance Standards
Program staff at (202) 586-1445 to discuss the need for alternative
arrangements. Once the COVID-19 pandemic health emergency is resolved,
DOE anticipates resuming all of its regular options for public comment
submission, including postal mail and hand delivery/courier.
Docket: The docket, which includes Federal Register notices, public
meeting/webinar attendee lists and transcripts, comments, and other
supporting documents/materials, is available for review at
<a href="http://www.regulations.gov">www.regulations.gov</a>. All documents in the docket are listed in the
<a href="http://www.regulations.gov">www.regulations.gov</a> index. However, some documents listed in the index,
such as those containing information that is exempt from public
disclosure, may not be publicly available.
The docket web page can be found at: <a href="http://www.regulations.gov/docket/EERE-2021-BT-TP-0019">www.regulations.gov/docket/EERE-2021-BT-TP-0019</a>. The docket web page contains instructions on how
to access all documents, including public comments, in the docket. See
section V ``Public Participation'' for information on how to submit
comments through <a href="http://www.regulations.gov">www.regulations.gov</a>.

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: <a href="/cdn-cgi/l/email-protection#09487979656068676a6c5a7d68676d687b6d7a587c6c7a7d6066677a496c6c276d666c276e667f">[email&#160;protected]</a>.
Mr. Eric Stas, U.S. Department of Energy, Office of the General
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585.
Telephone: (202) 586-5827. Email: <a href="/cdn-cgi/l/email-protection#9cd9eef5ffb2cfe8fdefdcf4edb2f8f3f9b2fbf3ea">[email&#160;protected]</a>.
DOE has submitted the collection of information contained in the
proposed rule to OMB for review under the Paperwork Reduction Act, as
amended. (44 U.S.C. 3507(d)) Comments on the information collection
proposal shall be directed to the Office of Information and Regulatory
Affairs, Office of Management and Budget, Attention: Sofie Miller, OIRA
Desk Officer by email: <a href="/cdn-cgi/l/email-protection#dba8b4bdb2bef5bef5b6b2b7b7bea99bb4b6b9f5beb4abf5bcb4ad">[email&#160;protected]</a>.
For further information on how to submit a comment, review other
public comments and the docket, or participate in the webinar, contact
the Appliance and Equipment Standards Program staff at (202) 287-1445
or by email: <a href="/cdn-cgi/l/email-protection#b2f3c2c2dedbd3dcd1d7e1c6d3dcd6d3c0d6c1e3c7d7c1c6dbdddcc1f2d7d79cd6ddd79cd5ddc4">[email&#160;protected]</a>.

SUPPLEMENTARY INFORMATION: DOE proposes to maintain and update
previously approved incorporations by reference and incorporate by
reference the following industry standard into parts 429 and 431:
AHRI Standard 1230, (``AHRI 1230-2021''), ``Performance Rating of
Variable Refrigerant Flow (VRF) Multi-Split Air-Conditioning and Heat
Pump Equipment;'' approved 2021.
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, (AHRI 1230-2010).
Copies of AHRI 1230-2021 and AHRI 1230-2010 can be obtained from
the Air-Conditioning, Heating, and Refrigeration Institute, 2311 Wilson
Blvd., Suite 400, Arlington, VA 22201 (703) 524-8800, or online at:
<a href="http://www.ahrinet.org/search-standards.aspx">www.ahrinet.org/search-standards.aspx</a>.
DOE proposes to amend the previously approved incorporation by
reference for the following industry standard in part 431:
ANSI/American Society of Heating, Refrigerating and Air-
Conditioning Engineers (ASHRAE) Standard 37-2009, ``Methods of Testing
for Rating Electrically Driven Unitary Air-Conditioning and Heat Pump
Equipment,'' ASHRAE approved June 24, 2009.
Copies of ANSI/ASHRAE 37-2009 can be obtained from the American
National Standards Institute, 25 W 43rd Street, 4th Floor, New York, NY
10036, (212) 642-4800, or online at: <a href="http://webstore.ansi.org/">webstore.ansi.org/</a>.
See section IV.M 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 Notice of Proposed Rulemaking
III. Discussion
A. Scope of Applicability
B. General Comments

[[Page 70645]]

C. Proposed Organization of the VRF Multi-Split System Test
Procedure
D. Industry Standards
1. Updates to AHRI 1230
2. ASHRAE 37
E. Metrics
1. IEER
2. Test Conditions Used for Efficiency Metrics
F. Test Method
1. Setting Indoor Airflow and External Static Pressure
2. Condenser Head Pressure Controls
3. Indoor Unit Operation During Part-Load Tests
4. Transient Testing: Oil Recovery Mode
5. Secondary Methods for Capacity Measurement
6. Heat Recovery
G. Specific Components
H. Controls Verification Procedure
1. Background
2. Purpose and Description
3. Critical Parameter Definition
4. Critical Parameter Variation and Budget Method
5. Validation of Certified Critical Parameters
6. Determination of Alternate Critical Parameters
7. When the CVP Is Conducted
I. Allowable Critical Parameter Adjustment
1. Adjustment of Certified Critical Parameter Values
2. Adjustment of Alternate Critical Parameter Values
J. Certification, Compliance and Enforcement
1. Represented Values
2. Certification Reporting Requirements
3. Models Required for AEDM Validation
4. Manufacturer Involvement
5. Certified Critical Parameter Operational Settings
6. Enforcement Sampling Plan
K. Test Procedure Costs
L. Reserved Appendices for Test Procedures for Commercial Air
Conditioning and Heating Equipment
M. Compliance Date
IV. Procedural Issues and Regulatory Review
A. Review Under Executive Order 12866
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. Description of Materials Incorporated by Reference
V. Public Participation
A. Participation in the Webinar
B. Procedure for Submitting Prepared General Statements for
Distribution
C. Conduct of the Webinar
D. Submission of Comments
E. Issues on Which DOE Seeks Comment
VI. 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 DOE is
authorized to establish and amend energy conservation standards and
test procedures. (42 U.S.C. 6311(1)(B) through (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 the test procedure for VRF multi-split systems
and relevant background information regarding DOE's consideration of
the test procedure for this equipment.

A. Authority

The Energy Policy and Conservation Act, as amended (``EPCA''),\1\
authorizes DOE to regulate the energy efficiency of a number of
consumer products and certain industrial equipment. (42 U.S.C. 6291-
6317) Title III, Part C \2\ of EPCA, Public Law 94-163 (42 U.S.C. 6311-
6317, as codified), added by Public Law 95-619, Title IV, section
441(a), established the Energy Conservation Program for Certain
Industrial Equipment, which 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 NOPR. (42
U.S.C. 6311(1)(B)-(D))
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\1\ All references to EPCA in this document refer to the statute
as amended through the Energy Act of 2020, Public Law 116-260 (Dec.
27, 2020).
\2\ For editorial reasons, upon codification in the U.S. Code,
Part C was redesignated Part A-1.
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The energy conservation program under EPCA consists essentially of
four parts: (1) Testing, (2) labeling, (3) Federal energy conservation
standards, and (4) certification and enforcement procedures. Relevant
provisions of EPCA include definitions (42 U.S.C. 6311), 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).
The Federal testing requirements consist of test procedures that
manufacturers of covered equipment must use as the basis for: (1)
Certifying to DOE that their equipment complies with the applicable
energy conservation standards adopted pursuant to EPCA (42 U.S.C.
6316(b); 42 U.S.C. 6296), and (2) making representations about the
efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE uses
these test procedures to determine whether the equipment complies with
relevant standards promulgated under EPCA.
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 the Air-
Conditioning, Heating, and Refrigeration Institute (``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 it 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))

[[Page 70646]]

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, the Secretary must publish proposed test
procedures in the Federal Register, and afford interested persons an
opportunity (of not less than 45 days duration) to present oral and
written data, views, and arguments on the proposed test procedures. (42
U.S.C 6314(b)) If DOE 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 proposing amendments to the test procedures 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 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
American National Standards Institute (``ANSI'')/AHRI Standard 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; 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. The May
2012 Final Rule also adopted additional requirements, listed in 10 CFR
431.96(c)-(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.
In 2016,\3\ 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 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 requirement. 82 FR 34427, 34429. 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.
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\3\ 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 <a href="http://www.ashrae.org/news/2016/ashrae-ies-publish-2016-energy-efficiency-standard">www.ashrae.org/news/2016/ashrae-ies-publish-2016-energy-efficiency-standard</a>. Last accessed April 30, 2021.
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DOE received a number of comments regarding VRF multi-split systems
from interested parties in response to the July 2017 ASHRAE TP RFI,
which covered multiple categories of equipment. Table I-1 lists the
commenters that provided comments relevant to VRF multi-split systems,
along with each commenter's abbreviated name used throughout this NOPR.
Discussion of the relevant comments, and DOE's responses, are provided
in the appropriate sections of this document.

Table I-1--Interested Parties Providing Comment on VRF Multi-Split
Systems in Response to the July 2017 ASHRAE TP RFI
------------------------------------------------------------------------
Name Abbreviation Type
------------------------------------------------------------------------
Air-Conditioning, Heating, and AHRI................. IR.
Refrigeration Institute.
Appliance Standards Awareness Joint Advocates...... EA.
Project, Alliance to Save Energy,
American Council for an Energy-
Efficient Economy, Northwest
Energy Efficiency Alliance, and
Northwest Power and Conservation
Council.
Carrier Corporation, part of United Carrier.............. M.
Technologies Climate, Controls &
Security Business.
Goodman Global, Inc................ Goodman.............. M.
Trane Technologies................. Trane................ M.
Lennox International Inc........... Lennox............... M.
Mitsubishi Electric Cooling & Mitsubishi........... M.
Heating, a division of Mitsubishi
Electric US, Inc.
National Comfort Institute......... NCI.................. IR.
Pacific Gas and Electric Company, CA IOUs.............. U.
Southern California Gas Company,
San Diego Gas and Electric, and
Southern California Edison
(collectively, California Investor-
Owned Utilities).
------------------------------------------------------------------------
EA: Efficiency/Environmental Advocate; IR: Industry Representative; M:
Manufacturer; U: Utility.

[[Page 70647]]

A parenthetical reference at the end of a comment quotation or
paraphrase provides the location of the item in the public record.\4\
In September 2017, AHRI published an update to ANSI/AHRI 1230,
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 \5\ and the Negotiated Rulemaking Act,\6\ 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.
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\4\ The parenthetical reference provides a reference for
information located in a docket related to DOE's rulemaking to
develop test procedure for VRF multi-split systems. As noted, the
July 2017 ASHRAE TP RFI addressed multiple different equipment
categories and is available under docket number EERE-2017-BT-TP-
0018. As this NOPR addresses only VRF multi-split systems, it has
been assigned a separate docket number i.e., EERE-2021-BT-TP-0019).
The references are arranged as follows: (Commenter name, comment
docket ID number, page of that document).
\5\ 5 U.S.C. App. 2, Public Law 92-463.
\6\ 5 U.S.C. 561-570, Public Law 104-320.
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The Working Group comprised 21 voting members including
manufacturers, energy efficiency advocates, utilities, and trade
organizations.\7\ On October 1, 2019, the Working Group reached
consensus on a term sheet (``VRF TP Term Sheet'') that includes the
following recommendations, which highlight the most substantial
changes: (Docket No. EERE-2018-BT-STD-0003-0044)
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\7\ A complete list of the ASRAC VRF Working Group members is
available at: <a href="http://www.energy.gov/eere/buildings/appliance-standards-and-rulemaking-federal-advisory-committee#Variable%20Refrigerant%20Flow%20Multi-Split%20Air%20Conditioners%20and%20Heat%20Pumps%20Working%20Group">www.energy.gov/eere/buildings/appliance-standards-and-rulemaking-federal-advisory-committee#Variable%20Refrigerant%20Flow%20Multi-Split%20Air%20Conditioners%20and%20Heat%20Pumps%20Working%20Group</a>.

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)
The additional recommended amendments are discussed further in
section III of this NOPR.
On May 18, 2021, AHRI published an updated industry standard for
VRF multi-split systems AHRI Standard 1230, ``2021 Standard for
Performance Rating of Variable Refrigerant Flow (VRF) Multi-Split Air-
Conditioning and Heat Pump Equipment'' (``AHRI Standard 1230-2021''),
which in turn references ANSI/ASHRAE Standard 37-2009 (including Errata
Sheet issued October 3, 2016) ``Methods of Testing for Rating
Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment''
(``ANSI/ASHRAE 37-2009'') for additional test setup and methodology
specifications. AHRI standard 1230-2021 is discussed in further detail
in section III.D.1 of this NOPR.

II. Synopsis of the Notice of Proposed Rulemaking

In this NOPR, DOE proposes to update Sec. 431.96, ``Uniform test
method for the measurement of energy efficiency of commercial air
conditioners and heat pumps,'' to align the relevant references to the
most recent version of the industry test procedure as follows: (1)
Incorporate by reference AHRI 1230-2021 and ANSI/ASHRAE 37-2009
(including Errata Sheet issued October 3, 2016); and (2) establish
provisions for determining IEER for VRF multi-split systems. DOE
further proposes to add new appendices D and D1 to subpart F of part
431, both entitled ``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 would be relocated to appendix D without change, and the new
test procedure adopting AHRI 1230-2021 would be established in appendix
D1 for determining IEER. Compliance with appendix D1 would not be
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 NOPR, DOE also proposes 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. Most significantly, these proposed 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. DOE is also proposing to amend the sampling size
requirements for enforcement from a maximum sample size of not more
than four units to require testing of two units.
DOE's proposed actions are summarized in Table II-1 and addressed
in detail in section III of this document.

Table II-1--Summary of Changes in Proposed Test Procedure Relative to
Current Test Procedure
------------------------------------------------------------------------
Proposed test
Current DOE test procedure procedure Attribution
------------------------------------------------------------------------
Incorporates by reference ANSI/ Incorporates by Updates to the
AHRI 1230-2010. reference in a new applicable
Appendix D1 AHRI 1230- industry test
2021 and ANSI/ASHRAE procedures.
37-2009 (including
Errata Sheet issued
October 3, 2016).
Includes provisions for Includes provisions Updates to the
determining EER. for determining both applicable
EER and IEER. industry test
procedures.
Does not include VRF-specific Includes provisions in Establish VRF-
provisions for determination 10 CFR 429.43 specific
of represented values in 10 specific to VRF multi- provision for
CFR 429.43. split systems to determination
determine represented of represented
values for units values.
approved for use with
multiple
refrigerants, and
determine represented
values for different
indoor unit
combinations.

[[Page 70648]]

Includes certification Adopts reporting Establish
requirements in 10 CFR 429.43 requirements reporting
consistent with testing to consistent with new requirements
EER per AHRI 1230-2010. test requirements of consistent with
AHRI 1230-2021, updated
including tested industry test
combination, method.
certified critical
parameter values, and
instructions for
conducting the
controls verification
procedure (``CVP'').
Does not include VRF-specific Adopts product- Establish
enforcement provisions in 10 specific enforcement provisions for
CFR 429.134. provisions for VRF DOE testing of
multi-split systems VRF multi-split
including: systems.
Verification of
cooling capacity,
configuration of unit
under test,
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.
Does not provide VRF-specific Specifies VRF-specific Establish AEDM
instruction for validating AEDM validation instructions
alternative methods for criteria that are specific to VRF
determining energy efficiency dependent on indoor multi-split
and energy use (``AEDM'') at unit combinations systems.
10 CFR 429.70. offered by the
manufacturer.
Requires selection of not more Specifies an Establish VRF-
than 4 samples for DOE enforcement testing specific
enforcement testing following sample size of 2 provision for
the sampling plan in 10 CFR units, with enforcement
429.110. compliance based on sampling plan.
the arithmetic mean
of the sample.
------------------------------------------------------------------------

DOE has tentatively determined that the proposed amendments
described in section III of this NOPR regarding the establishment of
appendix D would not alter the measured efficiency of VRF multi-split
systems, or require retesting solely as a result of DOE's adoption of
the proposed amendments to the test procedure, if made final. DOE has
tentatively determined that the proposed amendments regarding the test
procedure in proposed appendix D1 would alter measured efficiency if
made final and that such amendments are consistent with the updated
industry test procedure. Further, use of the updated industry test
procedure provisions as proposed and the proposed amendments to
representation requirements in 10 CFR 429.43 and 10 CFR 429.70 would
not be required until the compliance date of amended standards in terms
of IEER. Additionally, DOE has tentatively determined that the proposed
amendments, if made final, would not increase the cost of testing
relative to the updated industry test procedure. Discussion of DOE's
proposed actions are addressed in detail in section III of this NOPR.

III. Discussion

DOE's test procedure for VRF multi-split systems is set forth at
Sec. 431.96. DOE's current regulations require that manufacturers test
VRF multi-split systems using ANSI/AHRI 1230-2010 with Addendum 1,
except for Sections 5.1.2 and 6.6. See Table 1 at 10 CFR 431.96. DOE's
current test procedure also requires that manufacturers adhere to
certain additional requirements listed in 10 CFR 431.96(c) through (f),
which specify additional provisions for equipment set-up and provide
for limited involvement of manufacturer representatives during testing.
In the following sections, DOE discusses in detail relevant test
procedure issues and proposes changes to the current DOE test procedure
for VRF multi-split systems. DOE is generally proposing amendments such
that the Federal test procedure is consistent with AHRI 1230-2021 and
changes to the current certification, compliance and enforcement
(``CCE'') regulations for VRF multi-split systems, also consistent with
the updated industry test standard.

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. 10 CFR 431.92. 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 proposing to amend the current scope of the Federal test
procedure for VRF multi-split systems. DOE's 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,\8\ 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 10 CFR 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 NOPR
and will instead be 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.
---------------------------------------------------------------------------

\8\ 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. General Comments

In response to the July 2017 ASHRAE TP RFI, DOE received several
general

[[Page 70649]]

comments not specific to any one equipment category or test procedure.
This section addresses those comments.
NCI recommended that DOE follow the development of ASHRAE 221P,
``Test Method to Measure and Score the Operating Performance of an
Installed Constant Volume Unitary HVAC System,'' and consider where it
may be appropriately applied within EPCA test procedures. (NCI, No. 4
at pp. 1-2) NCI stated that it has collected data indicating that
typical split systems and packaged units serving residential and small
commercial buildings typically deliver 50 percent to 60 percent of the
rated capacity to the occupied zone, thereby making laboratory tests
unrepresentative of field performance. Id.
DOE notes that ASHRAE Standard 90.1 does not reference ANSI/ASHRAE
Standard 221-2020, ``Test Method to Field-Measure and Score the Cooling
and Heating Performance of an Installed Unitary HVAC System'' \9\ as
the applicable test procedure for VRF multi-split systems. NCI also did
not provide data on field performance or any correlations between field
performance and laboratory test performance for VRF multi-split systems
for DOE to consider. Furthermore, ASHRAE 221-2020 does not provide a
method to determine the efficiency of VRF multi-split systems. As
discussed, DOE is proposing to incorporate by reference AHRI 1230-2021,
the most recently published version of the industry test procedure
recognized by ASHRAE Standard 90.1 for VRF multi-split systems.
---------------------------------------------------------------------------

\9\ Available at <a href="https://webstore.ansi.org/Standards/ASHRAE/ANSIASHRAEStandard2212020">https://webstore.ansi.org/Standards/ASHRAE/ANSIASHRAEStandard2212020</a>.
---------------------------------------------------------------------------

The CA IOUs commented that while the July 2017 ASHRAE TP RFI
expressed interest in reducing burden to manufacturers, DOE already
took steps to reduce this burden by allowing alternative energy
efficiency or energy use determination methods (``AEDMs''). (CA IOUs,
No. 7 at pp. 1-2). The CA IOUs stated that there are no further
opportunities to streamline test procedures to limit testing burden.
Id. at 2. Additionally, the CA IOUs emphasized the importance of
accurate efficiency ratings for its incentive programs and customer
knowledge, referencing the statutory provision that test procedures
must produce results that are representative of the product's energy
efficiency. Id.
Lennox stated that it generally supports DOE meeting the statutory
requirements to design test procedures to measure energy efficiency
during an average use cycle, but requested that DOE also consider
overall impacts to consumers and manufacturers. (Lennox, No. 8 at pp.
1-2) Lennox also stated that, in commercial applications, predicting
actual energy use from a single metric is difficult, and such a metric
better serves as a point of comparison. Id. Lennox suggested that DOE
strike a balance between evaluating equipment in a meaningful way
without introducing unwarranted regulatory burden from overly complex
test procedures or calculations that provide little value to consumers.
Id.
In response to the CA IOUs and Lennox, DOE notes that its approach
to test procedures is governed by EPCA's requirements. As discussed,
EPCA prescribes that the test procedures for commercial package air
conditioning and heating equipment must be those generally accepted
industry testing procedures or rating procedures developed or
recognized by industry as referenced in ASHRAE Standard 90.1. (42
U.S.C. 6314(a)(4)(A)) If such an industry test procedure is amended,
DOE must update its test procedure to be consistent with the amended
industry test procedure, unless DOE determines by a rule published in
the Federal Register and supported by clear and convincing evidence
that the amended test procedure would not meet the requirements in 42
U.S.C. 6314(a)(2) and (3) related to representative use and test
burden. (42 U.S.C. 6314(a)(4)(B) and (C)) In establishing or amending
its test procedures, DOE must develop test procedures that are
reasonably designed to produce test results which reflect energy
efficiency, energy use, and estimated operating costs of a type of
industrial equipment during a representative average use cycle and that
are not unduly burdensome to conduct. (42 U.S.C 6314(a)(2)) DOE's
considerations of these requirements in relation to individual test
method issues are discussed within the relevant sections of this NOPR.
The Joint Advocates stated that there a number of ambiguities in
industry test procedures and that DOE should address these ambiguities
in order to provide a level playing field for manufacturers and to
ensure that any verification or enforcement testing is consistent with
the manufacturer's own testing. (Joint Advocates, No. 9 at p. 2)
DOE has evaluated the industry test standard in the context of the
statutory criteria regarding representativeness of the measured energy
efficiency and test burden. To the extent there are provisions in the
relevant industry test procedure that may benefit from further detail,
such provisions are discussed in the previous sections of this
document.

C. Proposed Organization of the VRF Multi-Split System Test Procedure

DOE is proposing to relocate and centralize the current test
procedure for VRF multi-split systems to a new appendix D to subpart F
of part 431. As proposed, appendix D would not amend the current test
procedure. The test procedure as provided in proposed appendix D would
continue to reference ANSI/AHRI 1230-2010 with Addendum 1 and provide
for determining EER and COP. The proposed appendix D would centralize
the additional test provisions currently applicable under 10 CFR
431.96, i.e., optional break-in period for tests conducted using AHRI
1230-2010 (10 CFR 431.96(c)); refrigerant line length corrections for
tests conducted using 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.
Pursuant to EPCA, DOE is also proposing 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 proposes to adopt the updated
version of AHRI 1230, including the IEER metric, as discussed in the
following sections. As proposed, VRF multi-split systems would not be
required to test 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.

D. Industry Standards

1. Updates to AHRI 1230
As discussed, DOE's current test procedure for VRF multi-split
systems incorporates by reference ANSI/AHRI 1230-2010, excluding
Sections 5.1.2 and 6.6. See Table 1 at 10 CFR 431.96. In September
2017, AHRI published an updated version of AHRI Standard 1230--AHRI
Standard 1230-2014 with Addendum 1 ``2014 Standard for Performance
Rating of Variable Refrigerant Flow (VRF) Multi-Split Air-Conditioning
and Heat Pump Equipment'' (AHRI 1230-2014 with Addendum 1). Based on a
comparison of the 2014 version and ANSI/AHRI 1230-2010, the edits
changed the scope of the VRF certification program and

[[Page 70650]]

VRF-specific definitions, and added appendices for unit configuration
for capacity above 65,000 Btu/h and development of supplemental testing
instructions. DOE tentatively concludes that the changes in the 2014
version do not substantively affect testing for EER (the current
Federal metric). Therefore, DOE has tentatively determined that its
current test procedure, which references ANSI/AHRI 1230-2010, is
consistent with AHRI 1230-2014 with Addendum 1.
As discussed in section I.B, the VRF TP Term Sheet recommended that
DOE adopt the 2019 draft version of AHRI 1230, but with several
additional changes to be implemented, including:
<bullet> 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'').
<bullet> Equations and example calculations of adjustments to
measured results for steady-state tests if sensible heat ratio
(``SHR'') \10\ limits are not met at the 100 percent full load and/or
75 percent part load cooling test points.
---------------------------------------------------------------------------

\10\ 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.
---------------------------------------------------------------------------

<bullet> Further definition of the draft CVP, including 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
outstanding items identified in the VRF TP Term Sheet. On 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'' (see section III.H.4 of this NOPR for
description of the critical parameter budget method). The AHRI 1230
Technical Committee incorporated a budget of 70 points (a measure of
critical parameter variation, as discussed in section III.H.4 of this
NOPR) in AHRI 1230.
Following the completion of the AHRI 1230 Technical Committee
meetings, in May 2021, AHRI published AHRI 1230-2021, which supersedes
AHRI 1230-2014 with Addendum 1. The 2019 draft considered by the
Working Group incorporated preliminary versions of the CVP, provided
example calculations for IEER, and added other new provisions to
clarify how the test procedure should be conducted. The changes
recommended in the VRF TP Term Sheet were incorporated into AHRI 1230-
2021. The following list includes substantive changes in AHRI 1230-2021
as compared to AHRI 1230-2010 currently used for certification:
1. 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.''
2. Maximum SHR limits of 0.82 and 0.85 were added for full load and
75 percent part-load conditions, respectively.
3. 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.
4. A hierarchy was added indicating which sources of manufacturer's
instructions to use during testing in the case of conflicting
information among different sources.
5. 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.
6. For water-source equipment, the maximum water flow rate was
reduced and part-load entering water temperatures were modified.
7. 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.
8. The provisions for tested combinations, which specify the indoor
unit combination to be used for testing, were updated to remove
``highest sales volume'' requirements and replaced with a specific
hierarchy based on ``indoor unit model family''--e.g., wall-mounted,
compact 4-way ceiling cassette, mid-static ducted.
9. A maximum airflow rate of 55 standard cubic feet per minute
(``scfm'') per 1000 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 1000 Btu/h to 42 scfm per 1000 Btu/h.
10. Test tolerances for indoor air entering wet-bulb temperatures
were increased. Specifically, the indoor wet-bulb temperature operating
tolerance was increased from 1 [deg]F to 1.8 [deg]F. The indoor wet-
bulb temperature condition tolerance was also increased from 0.30
[deg]F to 0.36 [deg]F. Additionally, the operating tolerance for
external static pressure (``ESP'') for ducted units was changed from
0.05 in H2O to 10 percent of the ESP reading.
11. 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.
12. 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.\11\
---------------------------------------------------------------------------

\11\ See section III.H.4 of this NOPR for further discussion of
the CVP budget method.
---------------------------------------------------------------------------

DOE is proposing to adopt the updated version of AHRI 1230,
including the IEER metric, as described further in section III.E of
this NOPR. DOE proposes to incorporate by reference AHRI 1230-2021 in a
new appendix D1 to subpart F of part 431, which would become required
for use starting on the compliance date for any amended energy
conservation standards based on IEER. DOE reviewed AHRI 1230-2021 to
determine whether it meets the requirements of EPCA for incorporation
by reference as part of the Federal test method for determining
compliance with minimum energy conservation standards. DOE has
tentatively determined that the changes in AHRI 1230-2021 better
reflect the field performance of VRF multi-split systems and provide
additional clarification for testing provisions. Specifically, in the
proposed test procedure for VRF multi-split systems in the proposed
appendix D1, DOE is proposing to reference the following

[[Page 70651]]

sections from AHRI 1230-2021: Section 3 (except 3.10), Section 5
(except 5.1.2), Section 6 (except 6.3.3 and 6.5), Section 11, and
Section 12. DOE is also proposing to reference appendix E from AHRI
1230-2021 but is not proposing to reference the other appendices. DOE
proposes to exclude the remaining sections from its test procedure for
VRF multi-split systems because they are 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 is proposing
modifications as discussed in the following sections of this NOPR, and
listed as excepted previously.
2. ASHRAE 37
ANSI/ASHRAE 37-2009, which provides a method of test for many
categories of air conditioning and heating equipment, is referenced for
testing VRF multi-split systems by ANSI/AHRI 1230-2010, ANSI/AHRI 1230-
2014 with Addendum 1, and AHRI 1230-2021. In particular, appendix E of
AHRI 1230-2021 provides additional instruction and exceptions regarding
the application of the test methods specified in ANSI/ASHRAE 37-2009 to
VRF multi-split systems. As stated, ANSI/ASHRAE 37-2009 is referenced
in ANSI/AHRI 1230-2010, which is currently the referenced industry test
standard in the DOE test procedure for VRF multi-split systems. To
reflect the use of ANSI/ASHRAE 37-2009 in conducting testing according
to AHRI 1230-2021, DOE is proposing to incorporate by reference ANSI/
ASHRAE 37-2009 in its test procedure for VRF multi-split systems.
Specifically, in the proposed appendix D1, DOE is proposing to
reference all sections of ANSI/ASHRAE 37-2009 except Sections 1, 2, and
4. Specific issues discussed in the July 2017 ASHRAE TP RFI pertaining
to ANSI/ASHRAE 37-2009, and the related comments, are addressed in
section III.F of this NOPR.
On October 3, 2016, ASHRAE published an errata sheet for ANSI/
ASHRAE 37-2009 that corrected the total heating capacity equations for
the outdoor liquid coil method in section 7.6.5.1 of the test
standard.\12\ Therefore, DOE proposes to incorporate by reference ANSI/
ASHRAE 37-2009 including the Errata sheet published on October 3, 2016
in the proposed appendix D1.
---------------------------------------------------------------------------

\12\ <a href="http://www.ashrae.org/standards-research--technology/standards-errata">www.ashrae.org/standards-research--technology/standards-errata</a>.
---------------------------------------------------------------------------

E. Metrics

1. IEER
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. Both EER and COP capture the
system performance at single, full-load operating points in cooling and
heating mode (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.
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. The IEER metric
was first introduced into ASHRAE 90.1 for commercial air-cooled, water-
cooled, and evaporatively-cooled air conditioning and heat pump
equipment in the 2008 Supplement to Standard 90.1-2007, effective
January 1, 2010. 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 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. VRF multi-split systems provide space heating and
cooling to commercial buildings in a similar range of climatic
conditions as ACUACs. In this NOPR, DOE has initially determined that
IEER represents the efficiency of VRF multi-split systems operating in
the field more accurately than EER because cooling loads do not require
operation at full-load for the vast majority of cooling hours.
As discussed in the July 2017 ASHRAE TP RFI, manufacturers already
test and rate VRF multi-split systems using the IEER metric in the AHRI
Directory of Certified Product Performance for VRF multi-split
systems.\13\ 82 FR 34427, 34445. The publication of IEER ratings for
most units on the market and the inclusion of minimum efficiency levels
and test procedures in terms of IEER for VRF multi-split systems in
ASHRAE Standard 90.1 and AHRI Standard 1230 indicates that IEER is an
industry-accepted and widely-used metric for measuring efficiency of
VRF multi-split systems. In the July 2017 ASHRAE TP RFI, DOE requested
comment on any issues it should consider regarding potentially using
IEER as an efficiency metric for air-cooled VRF multi-split systems
with a cooling capacity greater than or equal to 65,000 Btu/h and
water-source VRF multi-split systems. 82 FR 34427, 34445-34446.
---------------------------------------------------------------------------

\13\ The AHRI directory for VRF multi-split systems is available
at: <a href="http://www.ahridirectory.org/NewSearch?programId=72&searchTypeId=3">www.ahridirectory.org/NewSearch?programId=72&searchTypeId=3</a>.
---------------------------------------------------------------------------

In response to the July 2017 ASHRAE TP RFI, AHRI, Lennox,
Mitsubishi, Trane, Goodman, Carrier, the CA IOUs, and the Joint
Advocates all supported using an IEER metric for VRF multi-split
systems. (AHRI, No. 11 at p. 31; Lennox, No. 8 at p. 6; Mitsubishi, No.
10 at p. 1; Trane, No. 12 at p. 2; Goodman, No. 14 at p. 5; Carrier,
No. 6 at p. 17; CA IOUs, No. 7 at p. 4; Joint Advocates, No. 9 at p. 6)
AHRI, Goodman, and Carrier further commented that IEER should replace
EER as the Federal metric, and not be used as an additional metric.
(AHRI, No. 11 at p. 31; Goodman, No. 14 at p. 5; Carrier, No. 6 at p.
17) AHRI and Goodman asserted that EPCA requires DOE to establish a
single performance standard or a single design requirement. (AHRI, No.
11 at p. 31; Goodman, No. 14 at p. 5) The Joint Advocates commented
that VRF multi-split systems should be regulated based on both EER and
IEER, while the CA IOUs commented that the IEER metric is appropriate
as a national standard as long as the EER value at each of the test
points is individually published. (Joint Advocates, No. 9 at p. 6; CA
IOUs, No. 7 at p. 4) The Joint Advocates further commented that
regulating based on both EER and IEER would have no impact on test
burden because manufacturers are already rating their equipment for
both. (Joint Advocates, No. 9 at p. 6) CA IOUs also commented that the
highest ambient test point required by DOE's test procedure (95 [deg]F
outdoor air dry-bulb temperature) is not representative of VRF multi-
split systems operating conditions in the hot and dry western climate,
and

[[Page 70652]]

recommended adding a hot-dry condition test point in IEER. (CA IOUs,
No. 7 at p. 4)
During the proceedings of the ASRAC negotiated rulemaking process,
the Working Group discussed the appropriateness of rating VRF equipment
using an IEER metric at the test points prescribed in ANSI/AHRI 1230-
2010. (Docket No. EERE-2018-BT-STD-0003-0051 at pp. 13-14) The Working
Group also discussed the potential for adding new test points to the
IEER metric, including the proposal to add a hot-dry condition test
point for IEER, which was also suggested by the CA IOUs in their
response to the 2017 ASHRAE TP RFI. (EERE-2018-BT-STD-0003-0051; CA
IOUs, No. 7 at p. 4) Ultimately, the Working Group did not adopt a hot-
dry condition test point in its recommendations. The VRF TP Term Sheet
states that VRF multi-split systems should be rated with the IEER
metric to allow consumers to make consistent comparisons with other
products using the IEER metric. (Docket No. EERE-2018-BT-STD-0003-0044
at p. 1) Additionally, during a presentation delivered by DOE at the
September 20, 2019 Working Group meeting, AHRI indicated that they
would submit a letter to the docket stating that the AHRI certification
program would continue to use both EER and IEER cooling metrics for VRF
multi-split systems. (Docket No. EERE-2018-BT-STD-0003-0052 at p. 72).
In this NOPR, DOE is proposing to adopt the relevant provisions in
AHRI 1230-2021 to determine IEER for VRF multi-split systems. As noted,
the energy conservation standards for VRF multi-split systems are in
terms of EER. Testing according to the DOE test procedure to determine
EER would continue to be required until such time as the energy
conservation standards are amended to rely on IEER, should DOE adopt
such changes to the standards. Requiring both EER and IEER would result
in multiple standards applicable to the cooling function of a VRF
multi-split systems. However, EPCA directs DOE to establish an amended
uniform national standard for the relevant ASHRAE equipment at the
minimum level specified in the amended ASHRAE/IES Standard 90.1. (42
U.S.C. 6313(a)(6)(A)(ii)(I)) EPCA's use of ``uniform national
standard'' and ``minimum level'' appears to prohibit DOE from
establishing more than one standard applicable to the cooling function
of a VRF multi-split system. Id.
Based on the discussion in the preceding paragraphs, DOE initially
finds, that pursuant to 42 U.S.C. 6314(a)(4)(B)), there is a lack of
clear and convincing evidence to establish a test procedure for IEER
other than as specified in AHRI 1230-2021.
Consistent with DOE's proposal to adopt IEER in its test procedure
for VRF multi-split systems, DOE also proposes to amend the current
definition for ``Integrated Energy Efficiency Ratio, or IEER'' at Sec.
431.92 to differentiate between ACUACs and VRF multi-split systems.
Both systems would use the IEER efficiency metric, but the applicable
test procedures are in separate sections of the CFR. Specifically, DOE
proposes to amend the definition of ``Integrated Energy Efficiency
Ratio, or IEER'' at 10 CFR 431.92 to clarify that IEER is measured per
the test procedure in appendix A to subpart F of part 431 for ACUACs
and per the proposed test procedure at appendix D1 for VRF multi-split
systems.
Issue 1: DOE requests feedback on its proposal to adopt IEER as
determined under AHRI 1230-2021 in the Federal test procedure for VRF
multi-split systems. DOE also seeks comment on its proposed amendment
to the definition for IEER at Sec. 431.92 to distinguish between the
test procedures for ACUACs and VRF multi-split systems.
DOE notes that AHRI 1230-2021 also provides test methods and
calculations for measuring simultaneous cooling and heating efficiency
(``SCHE''). ASHRAE Standard 90.1-2019 does not include efficiency
levels for VRF multi-split systems in terms of SCHE, and the VRF TP
Working Group did not consider or analyze the SCHE metric (and thus it
was not included in the VRF TP Term Sheet). Further, SCHE is a
distinctly different metric from other efficiency metrics for VRF
multi-split systems, as SCHE combines cooling and heating performance
into a single metric. For these reasons DOE is not proposing to include
SCHE in its updated test procedure for VRF multi-split systems.
2. Test Conditions Used for Efficiency Metrics
AHRI 1230-2021 provides a number of test conditions for a variety
of tests referred to in the industry test procedure as ``standard
rating tests'' and ``performance operating tests.'' DOE is proposing 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.
a. Air-Cooled VRF Multi-Split Systems
Table 9 of AHRI 1230-2021 specifies test conditions for standard
rating and performance operating tests for air-cooled VRF multi-split
systems. Were DOE to amend the applicable energy conservation standards
based on AHRI 1230-2021, the relevant ratings for cooling tests would
be those referred to as ``standard rating conditions'' in AHRI 1230-
2021. To clarify this, DOE proposes 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 9 of AHRI 1230-2021.
For heating mode tests of air-cooled VRF multi-split systems, AHRI
1230-2021 includes ``Standard Rating Conditions'' for both a ``High
Temperature Steady-state Test for Heating'' and a ``Low Temperature
Steady-state Test for Heating'' (conducted at 47 [deg]F and 17 [deg]F
outdoor air dry-bulb temperatures, respectively). Were DOE to amend the
applicable energy conservation standards based on AHRI 1230-2021, the
relevant ratings would be those referred to as ``High Temperature
Steady-state Test for Heating'' in AHRI 1230-2021 and measured at 47
[deg]F. To clarify this, DOE proposes to specify in section 4.1 of
appendix D1 that the heating test conditions used for compliance would
be the ``Standard Rating Conditions (High Temperature Steady-state Test
for Heating)'' conditions specified in Table 9 of AHRI 1230-2021.
Additionally, DOE proposes to also include the low-temperature (17
[deg]F) heating test condition specified in Table 9 of AHRI 1230-2021
(referred to as ``Low Temperature Steady-state Test for Heating'') in
the proposed test procedure, and specify in section 4.1.1 of appendix
D1 that representations of COP at this low-temperature heating
condition are optional.
b. Water-Source VRF Multi-Split Systems
Tables 10 and 11 of AHRI 1230-2021 specify test conditions for
cooling mode and heating mode tests, respectively, for water-source VRF
multi-split systems. These tables include conditions for both standard
rating and performance operating tests. Furthermore, both tables
specify test conditions for three different applications of water-
source VRF multi-split systems: Water loop heat pumps, ground-water
heat pumps, and ground-loop heat pumps. Were DOE to amend the energy
conservation

[[Page 70653]]

standards based on AHRI 1230-2021, the relevant ratings for cooling and
heating tests would be those referred to as ``standard rating
conditions'' for ``water loop heat pumps'' in AHRI 1230-2021. To
clarify this, DOE proposes to specify in section 3.2 of the proposed
appendix D1 that the test conditions used for compliance would be the
``Part-load Conditions (IEER)'' conditions specified for ``Water Loop
Heat Pumps'' in Table 10 of AHRI 1230-2021 for cooling mode tests and
the ``Standard Rating Test'' conditions specified for ``Water Loop Heat
Pumps'' in Table 11 of AHRI 1230-2021 for heat pump heating mode tests.
DOE also proposes to include cooling and heating mode test
conditions specified for ``Ground-loop Heat Pumps'' in Tables 10 and 11
in the DOE test procedure for optional representations for water-source
VRF multi-split systems. Specifically, DOE proposes to specify in
section 4.2.1 of appendix D1 that representations of EER made using the
``Standard Rating Test'' conditions specified for ``Ground-loop Heat
pumps'' in Table 10 of AHRI 1230-2021 and representations of COP made
using the ``Standard Rating Test'' conditions specified for ``Ground-
loop Heat Pumps'' in Table 11 of AHRI 1230-2021 are optional.
The EPCA definition for ``commercial package air conditioning and
heating equipment'' specifically excludes ground-water-source equipment
(42 U.S.C. 6311(8)(A)). Therefore, DOE is not proposing to include test
conditions in the proposed Federal test procedure for making optional
representations of cooling and heating efficiency for water-source VRF
multi-split systems in the ``Ground-water Heat Pump'' application.

F. Test Method

This section discusses certain issues related to testing VRF multi-
split systems, several of which were identified by DOE in the July 2017
ASHRAE TP RFI and subsequently addressed in AHRI 1230-2021.
Additionally, several of the issues raised by DOE in the July 2017
ASHRAE TP RFI and by commenters relate to changes to the 2019 draft
version of AHRI 1230 recommended by the VRF TP Term Sheet. These VRF TP
Term Sheet recommendations have also been addressed in AHRI 1230-2021.
Therefore comments received regarding these issues are briefly
summarized but are otherwise addressed by referencing the relevant
language in AHRI 1230-2021.
1. Setting Indoor Airflow and External Static Pressure
The performance of a VRF multi-split system can be significantly
affected by variation in ESP or operation with an indoor airflow that
is different from the intended or designed airflow. In the July 2017
ASHRAE TP RFI, DOE raised several issues associated with setting indoor
airflow and ESP for VRF multi-split systems. 82 FR 34427, 34446. These
issues are addressed in Section 6.3.1 of AHRI 1230-2021, and DOE is not
proposing any deviations from those provisions. These issues are
discussed in the following sections.
a. Indoor Airflow and ESP Settings for Different Capacity Ranges
DOE noted in the July 2017 ASHRAE TP RFI that a 2015 draft version
of AHRI 1230 contained one set of instructions for setting the indoor
air flow rates for systems with capacities less than 65,000 Btu/h
(section 6.3.3.1) and another set for systems with capacities larger
than 65,000 Btu/h (section 6.4.1). 82 FR 34427, 34446. It was not clear
to DOE why alternate approaches are required for different systems,
because the indoor units generally do not differ by system capacity.
Id. Therefore, DOE requested comment on whether there should be a
consistent approach for setting indoor airflow and ESP across all
capacity ranges of VRF multi-split systems. Id. In response, Lennox
commented that the airflow and ESP requirements for VRF multi-split
systems with cooling capacity above and below 65,000 Btu/h should be
the same. (Lennox, No. 8 at p. 8). Carrier commented that the different
approach for setting indoor airflow rates across capacity ranges was
being addressed by AHRI in drafting AHRI 1230. (Carrier, No. 6 at p.
19) AHRI commented that a more recent draft of AHRI 1230 contained new
requirements for airflow, and that the test requirements would be
different for part-load conditions but consistent for full-load
conditions. (AHRI, No. 11 at pp. 34-35).
AHRI 1230-2021 includes updated provisions in Section 6.3.1 for
setting indoor airflow and ESP that apply to air-cooled VRF multi-split
systems with cooling capacity greater than or equal to 65,000 Btu/h and
to all water-cooled VRF multi-split systems. Air-cooled VRF multi-split
systems with rated cooling capacity less than 65,000 Btu/h are not
within the scope of AHRI 1230-2021, and are instead within the scope of
a different industry test procedure (AHRI 210/240-2023). Therefore,
test procedures for three-phase, air-cooled VRF multi-split systems
with cooling capacity less than 65,000 Btu/h are not being considered
in this NOPR. Those will be 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. DOE is not proposing any deviations from Section 6.3.1 of
AHRI 1230-2021 regarding setting indoor airflow and ESP.
b. Test Setup for Non-Ducted Indoor Units
DOE explained in the July 2017 ASHRAE TP RFI that if a common duct
is used for the combined discharge airflow of multiple individual
units, the airflow for each individual unit cannot be verified. 82 FR
34427, 34447. Even if the ESP is set to zero in an attempt to replicate
operation without ducting, based on a measurement of downstream
pressure in a discharge duct this does not always guarantee that flow
is identical to free discharge conditions, due to sensitivity of such
in-duct pressure measurements to the air movement in the duct. Id.
Finally, specification of unusually high air flows for testing of free
discharge in indoor units may boost measured performance inconsistent
with field operation. Id. DOE requested comment on how to confirm
airflow for each indoor unit individually, or when there is deviation
from free-discharge operation, when there is a common duct for multiple
individual units. Id.
In response, AHRI, Carrier, Mitsubishi, and Goodman commented that
it is not feasible nor economically justified to confirm airflow of
individual indoor units when a common duct is used. (AHRI, No. 11 at p.
35; Carrier, No. 6 at p. 20; Mitsubishi, No. 10 at p. 2; Goodman, No.
14 at p. 7) Specifically, AHRI stated that it is currently infeasible
to confirm airflow for multiple individual indoor units.\14\ (AHRI, No.
11 at p. 35) AHRI stated that the third-party laboratory that it uses
for its certification program is only equipped with one code tester
(i.e., airflow-measuring apparatus) per test room. (Id.) AHRI
suggested, however, that the use of thermocouple grids on every outlet
on each unit and temperature checks on indoor liquid and indoor gas per
unit, combined with static pressure taps, helps identify any potential
deviation from free-discharge

[[Page 70654]]

operation on any unit. (Id.) Lennox commented that the test protocol
for testing non-ducted indoor units does not guarantee zero static
pressure at the inlet and outlet of each indoor unit; however, solving
this issue is not easy due to laboratory limitations. (Lennox, No. 8 at
p. 8) Lennox suggested that improvement to the test method could be
made to measure airflow at each indoor unit, but that would require
larger and more test rooms. (Id.) Lennox noted that experience has
indicated that the common duct may show a lower airflow measurement
compared to measuring airflow of each non-ducted indoor unit
independently. (Id. at pp. 8-9)
---------------------------------------------------------------------------

\14\ AHRI stated that it is currently not feasible to test VRF
products with up to 12 indoor units. Given DOE's awareness that
industry has the capability to test VRF multi-split systems with up
to 12 indoor units, DOE interprets AHRI's comment as referring to
the infeasibility of confirming the airflow of individual indoor
units.
---------------------------------------------------------------------------

Section 6.3.1.3 of AHRI 1230-2021 allows the use of a common duct
to connect multiple indoor units to a single airflow-measuring
apparatus. To ensure that the tests for non-ducted indoor units are
being conducted under conditions that reflect operation absent the use
of a common duct, AHRI 1230-2021 specifies that a static pressure tap
be placed in the center of each face of each discharge chamber that
connects each indoor unit to the common duct, and that the static
pressure difference between each discharge chamber measurement and
intake opening of the equipment under test be zero. DOE tentatively
surmises that the approach provided in AHRI 1230-2021 represents
industry consensus regarding the most appropriate and representative
configuration for testing non-ducted indoor units. As discussed, DOE is
not proposing any deviations from the provisions in Section 6.3.1 of
AHRI 1230-2021 regarding setting indoor airflow and ESP.
c. Maximum Airflow Rate
Increasing the airflow rates at which indoor units of VRF multi-
split systems are tested generally improves measured performance.
Testing at an unusually high airflow rate may boost performance in a
manner inconsistent with field operation. As part of the July 2017
ASHRAE TP RFI, DOE requested comment on whether there should be an
upper limit of airflow per capacity for all non-ducted VRF indoor
units, such as 55 scfm per 1,000 Btu/h, which was the limit included in
the 2015 draft version of AHRI 1230. 82 FR 34427, 34447.
In response, AHRI, Carrier, and Goodman all expressed support for
an airflow limit of 55 scfm per 1,000 Btu/h for non-ducted units,
stating that such an upper limit would prevent manufacturers from
running higher airflows for rating purposes that are not typical for
actual use. (AHRI, No. 11 at pp. 34-35; Carrier, No. 6 at p. 20;
Goodman, No. 14 at p. 7) Lennox did not support the 55 scfm per 1,000
Btu/h airflow limit for non-ducted indoor units, and commented that to
align the test procedure with field operation, VRF multi-split systems
should be tested without an airflow limit. (Lennox, No. 8 at p. 9)
Section 6.3.1.3 of AHRI 1230-2021 includes an upper limit on
airflow per capacity for VRF multi-split systems with non-ducted indoor
units during cooling tests. The rated airflow for each non-ducted
indoor unit must not exceed the lower of two limits: (1) 105% of the
nominal airflow published in product literature for that indoor unit,
or (2) 55 scfm per 1,000 Btu/h of nominal indoor unit cooling capacity.
Section 6.3.1.3 of AHRI 1230-2021 also specifies that if a common duct
is used to measure airflow for multiple indoor units--if airflow is not
individually measured for each indoor unit--these limits are calculated
based on the sum of nominal capacities and nominal airflows for all of
the indoor units connected to the common duct. Section 6.3.1.4 of AHRI
1230-2021 specifies that these same provisions (in Section 6.3.1.3)
apply for ducted indoor units, except that the airflow limit for ducted
indoor units is 42 scfm per 1,000 Btu/h instead of 55 scfm per 1,000
Btu/h. DOE surmises that the approach to maximum airflow rate provided
in AHRI 1230-2021 represents the industry consensus regarding the most
appropriate and representative maximum airflow rate for testing VRF
multi-split systems. Therefore, DOE also surmises that Lennox's
position on these provisions, expressed in the comments in response to
the July 2017 ASHRAE TP RFI, changed while developing that industry
consensus standard. As discussed, DOE is not proposing any deviations
from the provisions in Section 6.3.1 of AHRI 1230-2021 regarding
setting indoor airflow and ESP.
2. Condenser Head Pressure Controls
Condenser head pressure controls regulate the flow of refrigerant
through the condenser and/or adjust operation of condenser fans/water
valves to prevent condenser pressures from dropping too low during low-
ambient operation. When employed, these controls ensure that the
refrigerant pressure is high enough to maintain adequate flow through
refrigerant expansion devices such as thermostatic expansion valves.
The use of condenser head pressure controls impacts a unit's
performance, making it important that this feature operate during
testing because it would operate in the field. In the July 2017 ASHRAE
TP RFI, DOE requested comment on the appropriateness of requiring head
pressure control activation during testing of VRF multi-split systems.
82 FR 34427, 34447.
AHRI, Mitsubishi, and Carrier stated that head pressure controls
should be activated during the test for VRF multi-split systems, as
manufacturers have different algorithms for controlling head pressure
and VRF multi-split systems cannot be maintained manually. (AHRI, No.
11 at p. 35; Mitsubishi, No. 10 at p. 2, Carrier, No. 6 at p. 20)
Goodman stated that head pressure control activation is not necessary
for testing, as all VRF multi-split systems are variable speed, and
system refrigerant pressures are kept at appropriate levels by
controlling the compressor and outdoor fan speed. (Goodman, No. 14 at
p. 7) Lennox stated that whether head pressure control is activated or
not will have no impact on testing. (Lennox, No. 8 at p. 8)
DOE also requested information regarding methods that could be
added to the test procedure for VRF multi-split systems to be used if
head pressure controls prevent stable operation at low-ambient, part-
load conditions, such as the special test provisions described in
section F7.1 of AHRI 340/360-2015 for CUACs. 82 FR 34427, 34441, 34447.
Specifically, DOE requested comment on whether a head pressure control
activation requirement was appropriate for testing of VRF multi-split
systems, as well as any additional methods that could be incorporated
into the VRF multi-split system test procedure to calculate system
efficiency if head pressure controls prevent stable operation at low-
ambient, part-load conditions. Id. In response, Goodman commented that
there is no need for head pressure control activation when testing,
and, therefore, no need to address head pressure control instability.
(Goodman, No. 14 at p. 7) Carrier commented that VRF manufacturers need
more time to evaluate the issue. (Carrier, No. 6 at p. 20)
Section 5.2 of AHRI 1230-2021 specifies that units with head
pressure controls have those controls enabled and operating in
automatic control mode during testing, set at factory settings or per
manufacturer installation instructions. Section 5.2.2 of AHRI 1230-2021
also includes a head pressure control time average test, to be used if
head pressure controls prevent a unit from achieving ``Stable
Conditions'' as defined by the test standard. Sections 5.2.3 and 5.2.4
provide additional direction for achieving stability, and are to be
used if the tolerances for the head

[[Page 70655]]

pressure control time average test cannot be met. Absent any indication
that activation of condenser head pressure controls results in test
results that are unrepresentative or that such activation is unduly
burdensome, DOE proposes adopting the AHRI 1230-2021 provisions
specifying activation of head pressure controls during testing, with
the additional clarification (in section 5.1 of the proposed appendix
D1) that head pressure controls are to be set per manufacturer
installation instructions or per factory settings if no instructions
are provided. DOE is not proposing any additional deviations from the
head pressure controls provisions in Section 5.2 of AHRI 1230-2021.
3. Indoor Unit Operation During Part-Load Tests
When VRF multi-split systems operate at low cooling loads in field
applications, typically only certain zones require cooling. Therefore,
at low cooling loads VRF indoor units serving zones with no cooling or
heating load typically turn off. In the July 2017 ASHRAE TP RFI, DOE
requested information and data on the field operating states of indoor
units of VRF multi-split systems when operating at low compressor
speeds, near 25-percent load. 82 FR 34427, 34446.
Commenters generally responded that applications vary greatly with
load characteristics, so there is not one operation mode that is
representative of all field scenarios, and therefore manufacturers
should not be required to turn off any indoor units during the test.
(AHRI, No. 11 at pp. 33-34; Goodman, No. 14 at p. 6; Mitsubishi, No. 10
at p. 2; Carrier, No. 6 at pp. 18-19; Lennox, No. 8 at p. 7)
Additionally, they commented that shutting off indoor units would
require retesting and would add burden and variability to the test
procedure. (Id.)
Section 5.10 of AHRI 1230-2021 requires that the number of indoor
units that are thermally active during full-load and part-load tests be
in accordance with the STI, and that at least half of the total indoor
units--as calculated per the total capacity of the connected indoor
units--remain thermally inactive for the 25 percent load test.
Furthermore, section 5.10 requires the following for thermally inactive
indoor units: (1) Forced air circulation through the units shall be
prevented (e.g., by blocking the inlet and outlet); and (2) the indoor
unit control settings shall be set to ``OFF'' (e.g., by using remote or
wireless thermostat). DOE surmises that AHRI's and industry's original
positions on these provisions regarding inactive indoor units, as set
forth in the comments in response to the July 2017 ASHRAE TP RFI,
changed while developing the industry consensus standard in AHRI 1230-
2021. DOE is not proposing any deviations from the provisions regarding
indoor units that are thermally active in Section 5.10 of AHRI 1230-
2021.
4. Transient Testing: Oil Recovery Mode
VRF multi-split systems may periodically operate in an oil recovery
mode to return oil from the refrigeration loop to the compressor. When
undergoing oil recovery, the compressor(s) may increase operating
speed, electronic expansion valves may open wider than normal, and
indoor fans may be turned off, to allow more liquid refrigerant mass
flow in the system. The higher refrigerant velocity helps to entrain
the compressor oil that was blocked in the indoor refrigerant lines and
return it to the compressor(s).
The current DOE test procedure for VRF multi-split systems
specifies through reference to ANSI/AHRI 1230-2010 that oil recovery
mode should be activated if the system is designed to initiate the oil
recovery mode more frequently than every two hours, but the test
procedure does not specify a transient test method or other provisions
specific to testing a unit with oil recovery. In the July 2017 ASHRAE
TP RFI, DOE requested comment on the impact of oil recovery mode on
power input and heating/cooling provided to space. 82 FR 34427, 34446
(July 25, 2017). DOE also requested comment on whether any VRF multi-
split systems operate in oil recovery mode more frequently than every
two hours of continuous operation. Id. For such systems, DOE requested
comment on whether and how the test method should address the transient
operation occurring during and after oil recovery. Id. In addition, DOE
requested comment on the performance variation associated with oil
level and whether all measurements should be made within a certain time
after the last oil recovery. Id. AHRI, Mitsubishi, Goodman, and Lennox
all commented that they did not support the incorporation of oil
recovery into the test procedure. (AHRI, No. 11 at p. 34; Mitsubishi,
No. 10 at p. 2; Goodman, No. 14 at p. 6; Lennox, No. 8 at p. 8) They
stated that oil recovery seldom occurs, and only during periods of time
at very low refrigerant flow rates, which would not be expected to
occur during testing. (Id.)
Section 5.1.3 of AHRI 1230-2021 specifies that oil recovery mode
must be activated during test, regardless of the frequency of oil
recovery cycles. If oil recovery occurs with a frequency that prevents
a steady state test, AHRI 1230-2021 specifies the use of the transient
test procedure as described in Section 8.8.3 (except Section 8.8.3.3)
of ANSI/ASHRAE 37-2009, with modifications described in Section 5.1.3.1
of AHRI 1230-2021. In light of the inclusion of oil recovery mode
provisions in AHRI 1230-2021, DOE surmises that AHRI's and industry's
original position on these conditions, as set forth in the comments in
response to the July 2017 ASHRAE TP RFI, changed while developing AHRI
1230-2021. DOE is not proposing any deviations from the provisions
regarding oil recovery mode in Section 5.1.3 of AHRI 1230-2021.
5. Secondary Methods for Capacity Measurement
Section 7.2.1 of ANSI/ASHRAE 37-2009 is referenced by AHRI 1230-
2021 and specifies the indoor air enthalpy method, plus an additional
secondary method for calculating the test equipment capacity for all
units with a rated cooling capacity less than 135,000 Btu/h.
Additionally, Section 10.1.2 of ANSI/ASHRAE 37-2009 specifies that the
secondary capacity measurement must agree with the primary capacity
measurement to within 6 percent for equipment with cooling capacity
less than 135,000 Btu/h. In the July 2017 ASHRAE TP RFI, DOE requested
comment on the methods generally used for measurement of capacity for
VRF multi-split systems and whether the selection of methods differs
between cooling and heating tests. 82 FR 34427, 34447. DOE also
requested comment on how to standardize the selection of test methods
for measuring the capacity of VRF multi-split systems. Id.
Commenters stated that there are challenges associated with
secondary capacity methods for VRF multi-split systems, such as the
refrigerant enthalpy and outdoor air enthalpy methods. (AHRI, No. 11 at
p. 36; Carrier, No. 6 at p. 21) For example, AHRI stated that the
refrigerant enthalpy method is not possible due to the range at which
the flow meter would need to operate, and the fact that the presence of
a metering device in the outdoor unit of some equipment would make it
impossible to use a refrigerant flow meter. (Id.) AHRI further stated
that the outdoor air enthalpy method is possible, but would require
multiple code testers for testing more than one outdoor unit, or
additional testing to cover multiple outdoor units tested together.
(Id.) Carrier stated that for heat pump VRF systems, the outdoor air
enthalpy may be used. (Carrier, No. 6 at p. 21) Carrier asserted that
this method would be

[[Page 70656]]

straightforward for single module systems; however, with multiple
module systems, testing would be very complex, if not impossible
because the ability to measure air flow and capacity from various
modules has not been achieved. (Id.) Carrier further stated that there
is no adequate secondary method for VRF systems with heat recovery.
(Id.) Carrier asserted that neither the refrigerant enthalpy nor
outdoor air enthalpy methods would work due to the complexity of the
refrigeration circuits in these units. (Id.)
Section 5.1.1 of AHRI 1230-2021 requires that VRF multi-split
systems be tested in accordance with ANSI/ASHRAE 37-2009, with
additional instruction provided in appendix E of AHRI 1230-2021.
Sections E9 and E13 of AHRI 1230-2021 include several modifications to
secondary capacity measurement method provisions in ANSI/ASHRAE 37-
2009. Specifically, section E9 provides that when using the outdoor air
enthalpy method as the secondary method, secondary checks are conducted
for only the high temperature full load tests for cooling and heating
mode. Section E13 modifies the outdoor air enthalpy method provisions
in Section 8.6 of ANSI/ASHRAE 37-2009--e.g., section E13 specifies that
the test used for capacity measurement for determination of efficiency
metrics is the test without the outdoor air-side test apparatus
connected to the outdoor unit. DOE surmises from the inclusion of these
secondary method provisions in AHRI 1230-2021 that AHRI's and
industry's original position on these conditions, as set forth in the
comments in response to the July 2017 ASHRAE TP RFI, changed during the
course of developing that industry consensus standard. DOE is not
proposing any deviations from the provisions regarding secondary
capacity measurement in appendix E of AHRI 1230-2021.
6. Heat Recovery
Some VRF multi-split systems include a heat recovery control unit
to control refrigerant flow between indoor units and provide heating
and cooling to different conditioned spaces simultaneously. In the July
2017 ASHRAE TP RFI, DOE requested comment on whether VRF multi-split
systems with heat recovery capability can be operated without the heat
recovery control unit attached, and if so, whether such systems are
typically tested for determining EER, IEER, and COP with the heat
recovery control unit attached. 82 FR 34427, 34447. DOE also sought
data showing differences in test results with the heat recovery unit
attached or unattached. Id.
AHRI, Lennox, and Carrier commented that heat recovery units should
be included during all tests for heat recovery systems. (AHRI, No. 11
at p. 36; Lennox, No. 8 at p. 9; Carrier, No. 6 at p. 21) AHRI and
Lennox stated that VRF heat recovery models cannot be operated without
the heat recovery unit attached because the unit is an integral part of
the system that cannot be removed, and, therefore, that the heat
recovery unit should be accounted for in testing. (Id.)
Section F2.3 of AHRI 1230-2021 specifies that individual models of
VRF multi-split systems distributed in commerce with heat recovery
components must be tested with the heat recovery components present and
installed. Consistent with Section F2.3 of AHRI 1230-2021, DOE proposes
at Sec. 429.43(a)(5) to specify 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.

G. Specific Components

An ASRAC working group for certain commercial heating, ventilating,
and air conditioning (``HVAC'') equipment (``Commercial HVAC Working
Group''),\15\ which included VRF multi-split systems, submitted a term
sheet (``Commercial HVAC Term Sheet'') providing the Commercial HVAC
Working Group's recommendations. (Docket No. EERE-2013-BT-NOC-0023, No.
52) \16\ The Commercial HVAC Working Group recommended that DOE issue
guidance under current regulations on how to test certain equipment
features when included in a basic model, until the testing of such
features can be addressed through a test procedure rulemaking. The
Commercial HVAC Term Sheet listed the subject features under the
heading ``Equipment Features Requiring Test Procedure Action.'' (Id at
pp. 3-9) The Commercial HVAC Working Group also recommended that DOE
issue an enforcement policy stating that DOE would exclude certain
equipment with specified features from Departmental testing, but only
when the manufacturer offers for sale at all times a model that is
identical in all other features; otherwise, the model with that feature
would be eligible for Departmental testing. These features were listed
under the heading ``Equipment Features Subject to Enforcement Policy.''
(Id. at pp. 9-15)
---------------------------------------------------------------------------

\15\ 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 <a href="http://www.regulations.gov">www.regulations.gov</a> under Docket
No. EERE-2013-BT-NOC-0023-0052.
\16\ Available at <a href="http://www.regulations.gov/document/EERE-2013-BT-NOC-0023-0052">www.regulations.gov/document/EERE-2013-BT-NOC-0023-0052</a>.
---------------------------------------------------------------------------

On January 30, 2015, DOE issued a Commercial HVAC Enforcement
Policy addressing the treatment of specific features during
Departmental testing of commercial HVAC equipment. (See <a href="http://www.energy.gov/gc/downloads/commercial-equipment-testing-enforcement-policies">www.energy.gov/gc/downloads/commercial-equipment-testing-enforcement-policies</a>) The
Commercial HVAC Enforcement Policy stated that--for the purposes of
assessment testing pursuant to 10 CFR 429.104, verification testing
pursuant to 10 CFR 429.70(c)(5), and enforcement testing pursuant to 10
CFR 429.110--DOE would not test a unit with one of the optional
features listed for a specified equipment type if a manufacturer
distributes in commerce an otherwise identical unit that does not
include one of the optional features. (Id at p. 1) The objective of the
Commercial HVAC Enforcement Policy is to ensure that each basic model
has a commercially available version eligible for DOE testing, meaning
that each basic model includes either a model without the optional
feature(s) or a model with the optional features that is eligible for
testing. Id. The features in the Commercial HVAC Enforcement Policy for
VRF multi-split systems, (id at p. 5), align with the Commercial HVAC
Term Sheet's list designated ``Equipment Features Subject to
Enforcement Policy.''
AHRI 1230-2021 includes Appendix F, ``Unit Configuration for
Standard Efficiency Determination--Informative.'' Section F2.4 includes
a list of features that are optional for testing. Section F2.4 of AHRI
1230-2021 further specifies the following general provisions regarding
testing of units with optional features:
<bullet> If an otherwise identical model (within the basic model)
without the feature is not distributed in commerce, conduct tests with
the feature according to the individual provisions specified in Section
F2.4 of AHRI 1230-2021.
<bullet> For each optional feature, Section F2.4 of AHRI 1230-2021
includes explicit instructions on how to conduct testing for equipment
with the optional feature present.
The optional features provisions in AHRI 1230-2021 are generally
consistent with DOE's Commercial HVAC Enforcement Policy, but the

[[Page 70657]]

optional features in Section F2.4 of AHRI 1230-2021 do not align with
the list of features included for VRF multi-split systems in the
Commercial HVAC Enforcement Policy. For VRF multi-split systems, the
Commercial HVAC Enforcement Policy specifies four optional features--
economizer, coated coil(s), steam/hydronic heat options, and
dehumidification components. Of these, steam/hydronic heat options and
coated coils are not included in the list of optional features in
Section F2.4. DOE understands AHRI 1230-2021 to represent the industry
consensus position on testing VRF multi-split systems. As such, DOE
understands the industry consensus to be that steam/hydronic heat
options and coated coils 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.
The list of optional features in Section F2.4 includes five
features that are not present in the Commercial HVAC Enforcement Policy
for VRF multi-split systems: low ambient cooling dampers, ventilation
energy recovery systems (``VERS''), power correction capacitors, hail
guards, and fresh air dampers. Three of these features in Section
F2.4--low ambient cooling dampers, hail guards, and fresh air dampers--
are included for VRF multi-split systems in the ``Equipment Features
Requiring Test Procedure Action'' section of the Commercial HVAC Term
Sheet. The remaining two features--power correction capacitors and
VERS--may be included in VRF multi-split systems distributed in
commerce. Therefore, DOE has tentatively concluded that their inclusion
as optional features for VRF multi-split systems is appropriate.
DOE notes that the list of features and provisions in Section F2.4
of appendix F of AHRI 1230-2021 conflates features that can be
addressed by testing provisions with features that warrant enforcement
relief (i.e., features that, if present on a unit under test, could
have a substantive impact on test results and that cannot be disabled
or otherwise mitigated). This differentiation was central to the
Commercial HVAC Term Sheet, which as noted previously, included
separate lists for ``Equipment Features Requiring Test Procedure
Action'' and ``Equipment Features Subject to Enforcement Policy,'' and
remains central to providing clarity in DOE's regulations.
Specifically, models including features for which the impact can be
addressed by testing provisions (e.g., UV lights, which can simply be
turned off for testing) should be subject to testing and do not warrant
enforcement relief (i.e., no provisions allowing representations based
on performance of an otherwise identical model without the feature, and
DOE compliance could be assessed based on testing of the model
containing the feature and not based on testing of an otherwise
identical model without the feature).
Further, Section F2.4 of AHRI 1230-2021 does not provide provisions
specific to how DOE would conduct enforcement testing with respect to
specific components, as opposed to how manufacturers make
representations. Therefore, provisions more explicit than those
included in Section F2.4 of AHRI 1230-2021 are warranted to clarify (1)
how manufacturers of VRF multi-split systems must make representations
with regards to specific components; and (2) how DOE will conduct
enforcement testing with respect to specific components (e.g., in which
situations DOE would test a tested combination including individual
indoor unit models with a specific component present).
In order to provide clarity between test procedure provisions
(i.e., how to test a specific unit) and certification and enforcement
provisions (e.g., which model to test), DOE is not proposing to
incorporate by reference appendix F of AHRI 1230-2021 and instead is
proposing related provisions in appendix D1 to subpart F of part 431,
Sec. 429.43, and Sec. 429.134. Specifically, in appendix D1, DOE
proposes test provisions for specific components, including all of the
components listed in Section F2.4 of 1230-2021. These provisions would
specify how to test a unit with such a component (e.g., for a unit with
hail guards, remove hail guards for testing). These proposed test
provisions are consistent with the provisions in Section F2.4 of AHRI
1230-2021 but include revisions for further clarity and specificity
(e.g., adding clarifying provisions for how to test units with modular
economizers as opposed to units shipped with economizers installed).
In Sec. 429.43(a)(4), DOE is proposing provisions that would
allow, in specific cases, determination of represented values for a
tested combination of VRF multi-split system based on performance of a
system without certain specific components. These provisions are
generally consistent with the Commercial HVAC Term Sheet, the
Commercial HVAC Enforcement Policy, and Section F2.4 of AHRI 1230-2021.
However, unlike in Section F2.4 of AHRI 1230-2021 (but consistent with
the Commercial HVAC Term Sheet and the Commercial HVAC Enforcement
Policy) and as discussed earlier in this section, the components to
which these provisions apply are limited to those components for which
the test provisions for testing a unit with these components may result
in differences in ratings compared to testing a unit without these
components--specifically, air economizers and dehumidification
components, which were included in both the Commercial HVAC Enforcement
Policy for VRF multi-split systems and appendix F of AHRI 1230-2021.
Also, because air economizers and dehumidification components are
only ever installed as part of the indoor units of VRF multi-split
systems, and VRF multi-split systems contain multiple indoor units with
potentially distinct model numbers, DOE proposes to adopt language more
specific to VRF multi-split systems than the language contained in the
Commercial HVAC Enforcement Policy and Section F2.4 of AHRI 1230-2021--
i.e., applying the provisions to multiple indoor unit models and tested
combinations. For example, DOE uses 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. This terminology allows for individual consideration of
specific components on an indoor unit-by-indoor unit basis to account
for scenarios in which one individual indoor unit model in the tested
combination may have an ``otherwise identical'' indoor unit model while
other individual indoor unit models in the tested combination may not
have an ``otherwise identical'' indoor unit model.
In summary, for air economizers and dehumidification components,
DOE proposes the following:
<bullet> If the indoor unit model(s) in a tested combination within
a basic model include only individual indoor unit models distributed in
commerce with a specific component, or does not include any otherwise
identical individual indoor unit models distributed in commerce without
the specific component, the manufacturer must determine represented
values for the tested combination based on performance of individual
indoor unit models with the component present (and consistent with any
relevant proposed test procedure provisions in appendix D1).
<bullet> If the indoor unit model(s) in a tested combination within
a basic model include both individual indoor unit models distributed in
commerce with a specific component and otherwise identical individual
indoor unit models

[[Page 70658]]

distributed in commerce without the specific component, the
manufacturer may determine represented values for the tested
combination based on performance of individual indoor unit models
either with the component present (and consistent with any relevant
proposed test procedure provisions in appendix D1) or without the
component present.
DOE notes that in some cases, individual indoor unit models may
include multiple of the specified components (i.e., both an economizer
and dehumidification components) or there may be individual indoor unit
models within a tested combination that include various
dehumidification components that result in more or less energy use. In
these cases, the represented values of performance must be
representative of the lowest efficiency found within the indoor unit
model(s) in a tested combination.
Additionally, DOE is proposing at Sec. 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 Sec. 429.43(a)(4). Specifically DOE proposes that the
manufacturer must certify for which specific components (as listed in
Sec. 429.43(a)(4)(i)), if any, 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.
Also consistent with the Commercial HVAC Term Sheet and the
Commercial HVAC Enforcement Policy, in 10 CFR 429.143(s)(1), DOE is
proposing provisions regarding how DOE would test tested combinations
within a basic model that include individual indoor unit models
distributed in commerce with air economizers or dehumidification
components. Specifically:
<bullet> If the manufacturer does not certify in accordance with 10
CFR 429.43(b)(4) both that (1) indoor unit model(s) in a tested
combination within a basic model include both individual indoor unit
models distributed in commerce with a specific component and otherwise
identical individual indoor unit models distributed in commerce without
the specific component and (2) represented values for the tested
combination are based on performance of individual indoor unit models
distributed in commerce without the specific component; then DOE may
test the tested combination with individual indoor unit models with the
component present (and consistent with any relevant proposed test
procedure provisions in appendix D1).
<bullet> If the manufacturer certifies in accordance with 10 CFR
429.43(b)(4) both that (1) indoor unit model(s) in a tested combination
within a basic model include both individual indoor unit models
distributed in commerce with a specific component and otherwise
identical individual indoor unit models distributed in commerce without
the specific component, and (2) represented values for the tested
combination are based on performance of individual indoor unit models
distributed in commerce without the specific component, DOE will test
the tested combination with otherwise identical indoor unit model(s)
within the tested combination within a basic model that do not include
the component, except in either of the following situations. In either
of the following situations, DOE may test the tested combination with
individual indoor unit models with the specific component present (and
consistent with any relevant proposed test procedure provisions in
appendix D1).
[cir] DOE is not able, through documented reasonable effort, to
obtain individual indoor unit models for testing that do not include
the component.
[cir] DOE becomes aware that the manufacturer's certification in
accordance with 10 CFR 429.43(b)(4) regarding specific components is
invalid.
Were DOE to adopt the provisions in appendix D1, Sec. 429.43, and
Sec. 429.134 as proposed, DOE would rescind the Commercial HVAC
Enforcement Policy to the extent it is applicable to VRF multi-split
systems. In a separate certification rulemaking, DOE may consider
requiring a manufacturer to identify, in its certifications, the
otherwise identical models that do not include specific component(s)
that are tested to support representations of basic models that include
individual models with specific components.
Issue 2: DOE requests comment on its proposals in appendix D1,
Sec. 429.43, and Sec. 429.134 regarding specific components.

H. 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 controls verification procedure (``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.H.5 of this NOPR 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.
DOE proposes to adopt the CVP that is specified in appendix C of
AHRI 1230-2021. Because the CVP is a verification procedure, not a test
procedure used to develop represented values, DOE is proposing to
distinguish the CVP as a validation procedure by adopting the CVP
procedure in the product-specific enforcement provisions for VRF multi-
split systems at Sec. 429.134(s). The proposed inclusion of these
provisions at Sec. 429.134(s) would indicate how DOE would conduct a
CVP in the event of assessment or enforcement testing. The following
sub-sections discuss the CVP and DOE's CVP-related proposals in detail.

[[Page 70659]]

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 DOE's current certification requirements for VRF multi-
split systems, found at Sec. 429.43(b)(4), specify that the STI must
include compressor frequency set points 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. Sections 5.1.2 and 5.1.3 of ANSI/AHRI 1230-2010 allow
similar adjustments of modulating components to achieve steady-state
conditions during ratings tests.
In October 2018, during the negotiation meetings of the Working
Group, the CA IOUs raised concern with 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) The CA IOUs presented field and
laboratory test data indicating decreased performance at part-load
conditions as compared to the part-load performance indicated by the
IEER rating and available published performance data for that system
when a VRF multi-split system was tested under commands from the system
controls (i.e., not manually controlled). Id. 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).
2. Purpose and Description
As discussed, Appendix C of AHRI 1230-2021 establishes a CVP.\17\
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.
---------------------------------------------------------------------------

\17\ 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 <a href="http://www.jsajis.org/index.php?main_page=product_info&cPath=2&products_id=13290">www.jsajis.org/index.php?main_page=product_info&cPath=2&products_id=13290</a>.
---------------------------------------------------------------------------

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
[deg]F and 86 [deg]F, and the VRF indoor units are set to control to a
constant indoor temperature, 80 [deg]F, except as explained by Section
5.1.5 of AHRI 1230-2021. This Section provides instructions for
adjusting the VRF indoor unit setpoints (deviating from 80 [deg]F) to
account for set point bias and set point offset.\18\ 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. 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 set point bias and offset to ensure repeatable
test results.
---------------------------------------------------------------------------

\18\ AHRI 1230-2021 provides the following definitions for these
terms in sections 3.29 and 3.30, respectively:
Set Point Bias--The difference between 80 [deg]F and the nominal
thermostat set point required for the thermostat to control for 80
[deg]F sensed temperature at the sensed location.
Set Point Offset--The difference between the temperature
indicated by a thermostat's temperature sensor and the actual
temperature at the sensor's location.
---------------------------------------------------------------------------

After setting initial indoor air temperature, including any
adjustments to control for set point 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.\19\ VRF
multi-split systems typically unload by modulating component settings,
including critical parameters, from the values used when providing
full-load cooling capacity. 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 (validation criteria are discussed in a
following section). Once the first indoor unit becomes thermally
inactive, the indoor room dry bulb temperature continues decreasing
until the indoor room reaches 77 [deg]F.
---------------------------------------------------------------------------

\19\ Figure C.1 in AHRI 1230-2021 displays an example schematic
of the indoor dry bulb temperature in [deg]F, compressor speed in
Hz, and the number of thermally active indoor units over the
duration of a CVP test.
---------------------------------------------------------------------------

3. Critical Parameter Definition
Section 3.10 of AHRI 1230-2021 defines the term ``critical
parameters'' as ``Key variables affecting the measured result,''
meaning ``[a]ny operating state or position for a component, either set
manually or automatically by System Controls, which significantly
impacts system performance.'' Section 5.1.2.1 of AHRI 1230-2021 limits
the range of critical parameters that can be manually adjusted to
compressor speed(s), outdoor fan speed(s) and outdoor variable valve
position(s). To be more explicit that ``critical parameters'' refers
only to those parameters specified by Section 5.1.2.1 of AHRI 1230-
2021, DOE is proposing not to reference the definition of critical
parameters in Section 3.10 of AHRI 1230-2021, and instead to define the
term ``critical parameter(s)'' 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). DOE has tentatively concluded that the proposed change to

[[Page 70660]]

the definition is editorial in nature and would not change or conflict
with any testing provisions in AHRI 1230-2021.
Issue 3: DOE requests comment on its proposed definition for
``Critical Parameter(s)'', which specifies the three parameters that
can be manually controlled in testing per Section 5.1.2.1 of AHRI 1230-
2021--compressor speed(s), outdoor fan speed(s), and outdoor variable
valve position(s).
4. Critical Parameter Variation and Budget Method
Appendix C of AHRI 1230-2021 includes methods for (1) calculating
variation of critical parameters measured during the CVP from the
values certified by the manufacturer in the STI (in Section C.4.4.2.3
of AHRI 1230-2021); and for (2) assessing whether the variation of
critical parameters from certified values is within acceptable limits
(in Section C.6 of AHRI 1230-2021).
Section C.4.4.2.3 of AHRI 1230-2021 provides instructions for
calculating critical parameter variation during the CVP, specifying
that at each measurement interval the instantaneous positions of all
critical parameters are compared to the certified values. If multiple
components corresponding to a single parameter are present (e.g.,
multiple compressors), the average position across all components is
calculated at each measurement interval when determining variation.
This difference is then divided by the maximum value observed during a
full-load cooling CVP, to arrive at a normalized percent difference
referred to as the ``Parameter Percent Difference'' or
``PPD<INF>i,t</INF>'' in AHRI 1230-2021.
Table C3 of AHRI 1230-2021 specifies weighting factors (referred to
as ``nominal point values''), which are multiplied by the
PPD<INF>i,t</INF> for each critical parameter. This results in a
``Points'' value (calculated per equation C4 of AHRI 1230-2021) for
each of the three critical parameters. These nominal point values
reflect the relative sensitivity of IEER to changes in each critical
parameter for VRF multi-split systems. The nominal point values
specified in Table C3 of AHRI 1230-2021 are independent of the load
point and whether the measured critical parameter is above or below the
STI-certified value. Section C6.1.1 of AHRI 1230-2021 specifies that
the Points values for each critical parameter are combined into a
single measure called ``RSS Points Total'' using a root-sum-squared
calculation. RSS Points Total represents an aggregated and normalized
measure of deviation of all critical parameters from their certified
values.
The verification criteria specified in Section C.6 of AHRI 1230-
2021 for critical parameters measured during the CVP is a ``budget
method'' that is dependent on cumulative variation across multiple
critical parameters, instead of being solely dependent on the behavior
of a single critical parameter. The budget method specified in Section
C.6 of AHRI 1230-2021 applies a limit to the calculated RSS Points
Total across all three critical parameters instead of applying
individual tolerances to each individual critical parameter.\20\ 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.
---------------------------------------------------------------------------

\20\ In addition to recommending inclusion of a CVP 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 that
were incorporated into the development of the ``budget method'' for
CVP critical parameter verification specified in section C6 of AHRI
1230-2021.
---------------------------------------------------------------------------

5. Validation of Certified Critical Parameters
As discussed in the preceding section, AHRI 1230-2021 includes a
budget method for calculating total variation in critical parameters
from their certified values, expressed as a point total instead of
measuring deviation individually for each critical parameter. 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 of AHRI 1230-2021 states that the manufacturer-specified
critical parameters are invalid if no 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. As
discussed in section III.D.1 of this NOPR, 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 allow
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. (Id). The Technical Committee ultimately agreed to
provide a 70-point budget in AHRI 1230-2021.
DOE has 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. The phrase
``a measurement period of at least three minutes and a minimum of five
sample readings'' could be understood to indicate a measurement period
with no upper limit, potentially encompassing the entire duration of
the CVP. This reading could be understood 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.
Therefore, DOE proposes to clarify these provisions by providing
additional instructions for validating critical parameters in Sec.
429.134(s)(3)(ii). Specifically, DOE proposes 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.
DOE also proposes 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.
Issue 4: DOE seeks comment on its proposal for adding provisions at
10

[[Page 70661]]

CFR 429.134(s)(3)(ii) to clarify the language in Sections C6.1.2 and
C6.1.3 of AHRI 1230-2021 for validating critical parameters during a
CVP, particularly pertaining to the duration of the measurement period
used for validating critical parameters.
6. Determination of Alternate Critical Parameters
AHRI 1230-2021 indicates that certified critical parameters shall
be consistent with a valid CVP to be used for IEER testing.
Specifically, Section 5.1.2.1 of AHRI 1230-2021 specifies that
operational settings for critical parameters must be with RSS Points
Total <=70 points, as defined in Section C6 of AHRI 1230-2021. However,
AHRI 1230-2021 does not explicitly provide for alternate critical
parameters for the IEER cooling test if the certified critical
parameters are invalidated by the CVP.
If a CVP is not conducted, or if a CVP is conducted and the
manufacturer-specified critical parameters are validated, DOE proposes
that the critical parameter values certified in the STI be used as the
initial control inputs when conducting the IEER cooling test at the
corresponding full- or part-load cooling condition. DOE understands
this to be consistent with Section 5.1.2 of AHRI 1230-2021. Because
AHRI 1230-2021 does not explicitly address how alternate critical
parameters are to be determined in the case of a failed CVP, additional
provisions are needed so that alternate critical parameters are
determined in a repeatable and representative manner. Therefore, if the
CVP invalidates the manufacturer-specified critical parameters, DOE
proposes at Sec. 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. DOE
proposes to use the same procedure for determination of measurement
period length as is proposed in Sec. 429.134(s)(3)(ii)(A) and
discussed in section III.H.5 of this NOPR: 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.
DOE also proposes 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. If
multiple such periods exist with the same RSS Points Total, DOE
proposes to select the period closest to (but before) the time when the
first indoor unit becomes thermally inactive (t<INF>Off</INF>).
As described in section III.H.4 of this NOPR, Point Total
represents an aggregated and normalized measure of deviation of all
critical parameters from their certified values; therefore, by
selecting a time period having the lowest average RSS Point Total, DOE
would be selecting the period from the CVP where the alternate critical
parameter values are most similar collectively to their certified
values. However, DOE acknowledges that other approaches could be
considered for selecting the measurement period for determination of
alternate critical parameters from a CVP that has invalidated the
critical parameter settings. For example, DOE could consider selecting
the measurement period based on the behavior of compressor speed alone
(e.g., the measurement period when deviation between certified and
measured compressor speed is minimized), irrespective of other critical
parameters. DOE could also consider selecting the measurement period
based on test chamber conditions--e.g., the measurement period when the
indoor test chamber first passes below the VRF multi-split system
thermostat setpoint, or the measurement period just before the first
indoor unit becomes thermally inactive.
Issue 5: DOE seeks comment on its proposal to specify at Sec.
429.134(s)(3)(iii)(B) how, in the event of a CVP that has invalidated
the critical parameter settings, alternate critical parameters would be
determined to use as initial control inputs during the corresponding
IEER full- or part-load cooling test. DOE requests feedback on the
proposed method for selecting a measurement period on the basis of
minimized average RSS points total, and also on its proposal for using
an average of critical parameter measurements over the selected
measurement period to calculate alternate critical parameters. DOE will
further consider any alternate approaches suggested by comments in
developing any final rule.
7. When the CVP Is Conducted
While appendix C of AHRI 1230-2021 details how to conduct a CVP, it
does not include instruction about the circumstances in which a CVP
must be conducted. As noted previously in section III.D.1, DOE is
proposing to adopt appendix C from AHRI 1230-2021 as a product-specific
enforcement provision, as opposed to adopting it in proposed appendix
D1. In other words, DOE is not proposing that the CVP be conducted as
part of an IEER test per the DOE test procedure. Instead, DOE is
proposing to include the CVP (via reference to appendix C of AHRI 1230-
2021) as part of DOE's product-specific enforcement provisions for VRF
multi-split systems in the proposed Sec. 429.134(s).
Issue 6: DOE requests comment on its proposal to incorporate the
CVP into its product-specific enforcement provisions for VRF multi-
split systems at Sec. 429.134(s) instead of the test procedure for VRF
multi-split systems in the proposed appendix D1.
In addition to its proposal to incorporate the CVP into its
product-specific enforcement provisions, DOE is proposing to specify at
Sec. 429.134(s)(3) that DOE would conduct a CVP at all of the four
IEER cooling test conditions, consistent with the Working Group
intention for DOE to verify controls performance. (Docket No. EERE-
2018-BT-STD-0003-0044 at p. 2) DOE also proposes 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.
DOE also proposes to specify that the CVP would be performed on a
single system from the two-system sample during enforcement testing. As
discussed in section III.H.5 of this document, DOE's preliminary
testing to evaluate repeatability and reproducibility of the CVP
indicated that a minimum point budget of 32 points would be required to
account for lab-to-lab and test-to-test variability observed in a
single system. A 70-point budget could therefore accommodate an
additional 48 points due to additional sources of variability,
including sample-to-sample variability across the same VRF multi-split
system. DOE has tentatively determined that the 70-point budget would
be sufficient to account for all sources of variability during testing,
such that conducting the CVP on a single system from the assessment/
enforcement sample would yield results that are representative of both
systems in the sample.
Should alternate critical parameters be required as a result of a
CVP that has invalidated the critical parameter settings, DOE proposes
that the alternate critical parameters would be determined from the CVP
results of the single

[[Page 70662]]

system. These alternate critical parameters would be used for the
corresponding IEER test (as specified in appendix D1) for all systems
tested as part of the enforcement sample. Figure 1 shows a diagram
illustrating DOE's proposed use of the CVP in its enforcement
provisions for VRF multi-split systems.
Issue 7: DOE requests comment on its proposed approach for
conducting the CVP during enforcement testing. Specifically, DOE
requests comment on the proposal that DOE would conduct the CVP for a
single system during enforcement testing in order to validate the
certified critical parameters. If commenters believe conducting the CVP
on a single system as part of enforcement testing is insufficient, DOE
requests 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.
[GRAPHIC] [TIFF OMITTED] TP10DE21.009

I. 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 for the given IEER test point.
Upon review of these provisions, DOE has tentatively determined that
several amendments are required, and, therefore, proposes to include
provisions to specify allowable critical parameter adjustments in
section 5.2 of appendix D1 to subpart F of part 431.
Section 6.3.3.1.2 of AHRI 1230-2021 specifies that in cases for
which the cooling capacity is above the upper tolerance, the critical
parameters are adjusted according to the instructions provided in the
STI--specifically, the manufacturer may specify that any or all of the
three critical parameters are to be adjusted in this scenario. Section
6.3.3.1.2 further specifies that when adjusting critical parameters,
the allowable adjustment is constrained by deviation resulting in an
RSS points total of 70 points or fewer. However, this section does not
explicitly describe RSS points total, nor does it refer to the
provisions in Sections C4.4.2.3 and C6 that specify measurement and
calculation of RSS points total in the context of a CVP. To remedy
this, DOE is proposing 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. These proposed instructions are consistent with the
provisions in Section C4.4.2.3 of AHRI 1230-2021 for calculating
critical parameter variation in a CVP, except that DOE proposes to
specify that the normalized deviation is to be measured between the
certified STI values and the adjusted critical parameter values during
steady-state IEER cooling tests, rather than between the certified STI
values and an instantaneous measurement of critical parameter positions
recorded during the CVP.
DOE is proposing two other clarifications to the provisions for
critical parameter adjustment for IEER tests in section 5 of appendix
D1. First, DOE is proposing to clarify 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. This is consistent with AHRI 1230-2021,
which does not require an RSS Points Total budget be used for these
adjustments.

[[Page 70663]]

Second, DOE proposes to clarify 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). Specifically, DOE proposes to
replace all references to ``multiple instances of a single parameter''
with ``multiple components corresponding to a critical parameter''.
This proposal is consistent with AHRI 1230-2021, but clarifies the
wording because ``multiple instances'' could be interpreted to refer to
multiple time points for a single component, rather than multiple
components at a given time, as intended.
To the extent that the industry test procedure does not provide the
specifications regarding adjustment of critical parameters as proposed,
DOE tentatively finds that the industry test procedure would not ensure
that measured results are comparative. Due to the potential variation
resulting from the absence of the specification, the industry test
procedure would not ensure that the results reflect the equipment's
representative average energy efficiency or energy use. As such, DOE
has initially determined, supported by clear and convincing evidence,
that in the absence of the proposed specifications for adjustment of
critical parameters the industry test procedure would not meet the
statutory requirements of 42 U.S.C. 6314(a)(2)-(3), and, therefore, is
proposing the supplemental specification.
Issue 8: DOE seeks comment on its proposed provisions (to clarify
similar provisions in AHRI 1230-2021) in section 4 of the proposed
appendix D1 to subpart F of part 431 that specify allowable adjustments
to critical parameters for IEER tests. Specifically, DOE requests
feedback on its proposal to specify, for IEER tests for which the
tested capacity is above the target capacity, calculation of normalized
critical parameter variation during the adjustment process (similar to
the calculation specified for the CVP in Section C4.4.2.3 of AHRI 1230-
2021).
2. Adjustment of Alternate Critical Parameter Values
As described in section III.H.5 of this NOPR, in the case of
critical parameter values being invalidated by the CVP conducted as
part of DOE assessment or enforcement testing, DOE is proposing to
clarify how alternate critical parameters would be determined for use
as control inputs for a steady-state cooling test conducted at the
corresponding IEER test condition (instead of using the critical
parameter values certified in the STI). In such a case, it may still be
necessary to adjust the alternate critical parameter values (determined
in the CVP) in order to meet tolerances for capacity and SHR limits for
the IEER test. Accordingly, DOE is proposing to include provisions at
Sec. 429.134(s)(3)(iii)(B)(3) to indicate 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 to comply with capacity and/or SHR requirements.
Specifically, DOE proposes to reference the methods for adjustment of
critical parameters from section 5.2 of appendix D1 to subpart F of
part 431 with two modifications. First, DOE proposes 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,
in such a case DOE proposes to determine the maximum operating state of
each critical parameter (referred to as CP<INF>Max</INF> 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.
Issue 9: DOE seeks comment on the proposed provisions at Sec.
429.134(s)(3)(iii)(B)(3) regarding allowable adjustment (to meet
tolerances for capacity and SHR limits for an IEER test) of alternate
critical parameter values determined by DOE in the event of a CVP that
has invalidated the critical parameter settings.

J. Certification, Compliance and Enforcement

1. Represented Values
a. Tested Combination
In the July 2017 ASHRAE TP RFI, DOE noted that Section 6.2.1 of the
2015 draft version of AHRI 1230 included the following specification
for tested combinations for systems with capacities greater than or
equal to 65,000 Btu/h: Testing with standard 4-way ceiling cassette
indoor units with the smallest coil volume per nominal capacity for
non-ducted indoor units, and testing with mid-static units for ducted
indoor units. 82 FR 34427, 34447. DOE also stated that there is a range
of ductless indoor unit styles, which may have a range of efficiency
characteristics, and that ducted systems may serve a range of ESPs. 82
FR 34427, 34447-34448 (July 25, 2017). DOE requested comment and data
on variation of system efficiency related to indoor unit styles (both
for ducted and non-ducted indoor units). Id. at 82 FR 34448. DOE also
requested data on the most prevalent style and static pressure
classification (low-static, mid-static, or conventional-static) of
ducted units. Id.
AHRI, Carrier, Lennox, Mitsubishi, and Goodman commented that the
4-way ceiling cassette and mid-static unit styles specified by the 2015
draft version of AHRI 1230 for the tested combination of non-ducted and
ducted indoor units, respectively, are the most common. (AHRI, No. 11
at p. 36; Carrier, No. 6 at pp. 22; Lennox, No. 8 at p.10; Mitsubishi,
No. 10 at p.3; Goodman, No. 14 at p.7) AHRI additionally stated that it
had recently surveyed its members and confirmed that these types of
indoor units are the most prevalent in the industry. (AHRI, No.11 at p
36)
Section 6.2 of AHRI 1230-2021 specifies tested combination
requirements for VRF multi-split systems that generally align with the
specifications from AHRI 1230-2015 draft, with a few amendments. First,
AHRI 1230-2021 amends the instructions for determining which indoor
units to use if the primary option is not offered by the manufacturer.
Instead of relying on the ``highest sales volume'' designation for
determining the alternate indoor units to compose the tested
combination, Section 6.2.1.1 of AHRI 1230-2021 specifies the following
hierarchy of non-ducted indoor units: Compact 4-way ceiling cassette,
three-way cassette, two-way cassette, wall-mounted, one-way cassette,
floor-mounted, and ceiling-suspended. Section 6.2.1.2 of AHRI 1230-2021
specifies that the tested combination must use indoor units (with the
lowest normalized coil volume) only from the indoor unit model family
with the highest static capabilities. Second, AHRI 1230-2021 adds
tested combination instructions for the new SDHV indoor unit model
family. Specifically, Section 6.2.1.3 of AHRI 1230-2021 specifies that
small-duct high velocity (SDHV) \21\ tested combinations must use
indoor units

[[Page 70664]]

with the lowest normalized coil volume/motor efficiency.
---------------------------------------------------------------------------

\21\ Section 3.17.3 of AHRI 1230-2021 defines the SDHV indoor
unit model family to include indoor units that produce at least 1.2
inches water column of ESP when operated at the full-load cooling
airflow of at least 220 scfm per rated ton of nominal cooling
capacity. These criteria align with DOE's definition for ``small-
duct high velocity system'' included in appendices M and M1 to
subpart B of part 430, for consumer central air conditioners. The
definition in Section 3.17.3 of AHRI 1230-2021 further provides
additional clarification that the SDHV indoor unit model family is a
separate indoor unit model family type that is not one of the ducted
indoor unit model families.
---------------------------------------------------------------------------

Although the tested combination is relevant to determination of
represented values, rather than the method of test, DOE has tentatively
determined that the AHRI 1230-2021 provisions regarding tested
combination are appropriate. Therefore, for ease of use, DOE is
proposing to incorporate by reference Section 6.2.1 of AHRI 1230-2021
in appendix D1 to subpart F of part 431.
b. Represented Values for Indoor Unit Combinations
DOE includes requirements for determining represented values for
all commercial HVAC equipment (including VRF multi-split systems) in
Sec. 429.43(a). Represented values for each VRF multi-split system
basic model must be determined either through testing in conjunction
with the applicable sampling provisions in Sec. 429.43(a)(1), or
through application of an AEDM in accordance with the provisions in
Sec. 429.43(a)(2). In addition, DOE's current test procedure
incorporates by reference Section 5.2 of ANSI/AHRI 1230-2010, which
includes requirements for determining represented values of VRF multi-
split systems through testing. However, DOE does not currently specify
in Sec. 429.43(a) any provisions specific to VRF multi-split systems
for determining represented values.
In considering possible options for determining represented values
for VRF multi-split systems, DOE reviewed AHRI 1230-2021, which
includes provisions for determining represented values of VRF multi-
split systems through testing in Section 7. Section 7.2.5 specifies
provisions pertaining to represented values of different combinations
of indoor unit types. Specifically, for basic models that include only
non-ducted or only ducted indoor unit combinations, Section 7.2.5.1
states that ratings are determined by testing at least two complete
system samples of the same combination of indoor units. Section 7.2.5.2
states that for manufacturers who offer both non-ducted combinations
and ducted combinations, ratings are determined by testing two or more
combinations of indoor units with each outdoor unit, with one
combination consisting of only non-ducted indoor units and the second
combination consisting of only ducted indoor units. Additionally,
Section 7.2.5.2.3 specifies that the rating given to any untested
system with a mix of ducted and non-ducted units is to be set equal to
the average of the ratings for the non-ducted and ducted tested
combinations.
As discussed in section III.J.1.a of this NOPR, Section 6.2 of AHRI
1230-2021 includes provisions regarding tested combinations of three
overall types: Non-ducted, ducted, and SDHV. However, Section 7.2.5 of
AHRI 1230-2021 addresses only ducted and non-ducted combinations, and
does not include provisions for determining represented values through
testing of VRF multi-split systems with SDHV indoor units. While
Section 7.2.2 of AHRI 1230-2021 states that mixed ratings must be
determined by the straight average of two individual systems' rated
values containing homogenous kinds of indoor units, including non-
ducted, ducted, and SDHV, Section 7.2.5 addresses mixed ratings of only
non-ducted and ducted tested combinations.
DOE proposes to adopt requirements at Sec. 429.43(a)(3)(iv)(B) for
determining represented values for VRF multi-split systems that are
consistent with the requirements from Section 7.2.5 of AHRI 1230-2021,
but with additional detail to address SDHV indoor units and with
language more appropriate for DOE's certification regulations. If a
basic model includes only non-ducted indoor units, only ducted indoor
units, or only SDHV indoor units, DOE proposes that the manufacturer
must determine the represented values for the basic model by testing a
sample of non-ducted tested combinations, ducted tested combinations,
or SDHV tested combinations, as applicable, according to the sampling
plan in Sec. 429.43(a)(1), or by application of an AEDM as specified
in Sec. Sec. 429.43(a)(2) and 429.70. If a basic model includes more
than one type of indoor unit combination--ducted, non-ducted, and/or
SDHV--DOE proposes that the manufacturer must determine separate
represented values for each type of indoor unit combination. DOE
further proposes to specify that the represented values must be
determined either through application of an AEDM, following provisions
from Sec. Sec. 429.43(a)(2) and 429.70), or through testing a minimum
of a single tested combination for each type of indoor unit combination
included in that basic model.
Additionally, DOE proposes that a manufacturer may determine
represented values for optional ``mixed'' representations of any two
required representations (i.e., ducted, non-ducted, and/or SDHV) for a
basic model by calculating the mean of the two required
representations. For example, if a basic model includes representations
for ducted and non-ducted indoor unit combinations, an optional ``mixed
ducted/non-ducted'' representation would be determined by averaging the
ducted representation and the non-ducted representation.
These proposals would only be required when certifying to amended
standards in terms of IEER. DOE has tentatively determined that the
proposed provisions would not be unduly burdensome to manufacturers.
DOE typically requires manufacturers to follow the sampling plan in
Sec. 429.43(a)(1) for all representations based on testing (i.e., a
minimum of two test samples per represented value), rather than
distributing the sampling plan testing requirements across a basic
model with multiple representations (i.e., the proposed approach for
requiring only a single tested system per representation). However, DOE
has tentatively concluded that the test burden for VRF multi-split
systems is significantly higher than that of other commercial AC
equipment, which warrants the proposed reduced testing requirements for
determining represented values. VRF multi-split systems are tested with
up to twelve indoor units connected in a single refrigerant circuit,
which requires additional set-up and commissioning time to install
refrigerant piping and ensure proper charge compared to testing other
kinds of commercial HVAC equipment. This often requires VRF multi-split
systems to be tested using 2 indoor test chambers in order to
accommodate all 12 indoor units, while other types of commercial HVAC
equipment only ever require a single indoor test chamber.
Further, DOE understands that most manufacturers of VRF multi-split
systems offer both ducted and non-ducted indoor units for most basic
models; therefore, for most basic models with representations based on
testing, manufacturers would still be testing at least two samples
(e.g., one with non-ducted indoor units and one with ducted indoor
units). Consequently, DOE has tentatively concluded that the proposed
reduced testing requirements will reduce test burden while being
reasonably designed to produce test results which reflect energy
efficiency of the VRF multi-split systems during a representative
average use cycle. Of note, DOE's enforcement regulations in subpart C
to part 429 apply to a basic model, not to a representation. Therefore,
the entire basic model would be considered non-compliant if any of the
representations for that basic model were found to be invalid.
Issue 10: DOE requests comment on its proposals for determining
represented values for VRF multi-split system basic models with
different

[[Page 70665]]

indoor unit combinations. In particular, DOE seeks feedback on its
proposal to allow for optional mixed representations of any two
required representations (i.e., ducted, non-ducted, and/or SDHV) for a
basic model by calculating the mean of the two required
representations.
c. Multiple Refrigerants
DOE recognizes that some commercial package air conditioning and
heating equipment may be sold with more than one refrigerant option
(e.g., R-410A or R-407C). Typically, manufacturers specify a single
refrigerant in their literature for each unique model, but in its
review, DOE has identified at least one commercial package air
conditioning and heating equipment manufacturer that provides two
refrigerant options under the same model number. The refrigerant chosen
by the customer in the field installation may impact the energy
efficiency of a unit. For this reason, DOE is proposing representation
requirements applicable to models approved for use with multiple
refrigerants. These proposals would only be required when certifying to
amended standards in terms of IEER.
Use of a refrigerant that requires different hardware (such as R-
407C as compared to R-410A) would represent a different basic model,
and according to the current CFR, separate representations of energy
efficiency are required for each basic model. In contrast, some
refrigerants (such as R-422D, R-427A) would not require different
hardware, and a manufacturer may consider them to be the same basic
model, per DOE's current definition for ``basic model'' at Sec.
431.92. In the latter case of multiple refrigerant options that do not
require different hardware, DOE proposes at Sec. 429.43(a)(3)(iv)(A)
that 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. These represented values
would apply to the basic model for all refrigerants specified by the
manufacturer as appropriate for use, regardless of which refrigerant
may actually be used in the field.
Issue 11: DOE requests comment on its proposal regarding
representations for VRF multi-split system basic models approved for
use with multiple refrigerants.
d. Confidence Limit
DOE's regulations for commercial HVAC (including VRF multi-split
systems) at Sec. 429.43(a)(1) include requirements for determining
represented values based on a sample of tested units. Specifically,
represented values for energy efficiency of a basic model of VRF must
be less than or equal to the mean of the sample of tested units or the
lower 95 percent confidence limit, whichever is lower.
In a comment submitted in response to the July 2017 ASHRAE TP RFI,
Lennox recommended that DOE harmonize the certification criteria in 10
CFR 429.43 for ``commercial air conditioning products'' with that for
central air conditioners, a consumer product, in 10 CFR 429.16 that
uses only a 90 percent confidence interval. (Lennox, No. 8 at p. 6). In
particular, Lennox stated that commercial equipment currently has a
more stringent confidence limit of 95 percent and asserted that current
testing technology does not support this level of precision. (Id.)
Lennox's recommendation for a narrower confidence interval would
decrease the level of certainty that a tested efficiency would be
greater than the rated efficiency, assuming the same test sample size.
Other manufacturers did not raise concerns regarding the confidence
limit required for sampling commercial package air conditioners and
heat pumps (including VRF multi-split systems), and Lennox did not
provide data regarding variability of units in production and testing
to support a different confidence limit. Absent more specific
information or data regarding the stringency of the confidence level,
DOE is not proposing to adopt the suggested change.\22\
---------------------------------------------------------------------------

\22\ DOE notes that it has previously requested data regarding
the variability of units of small, large, and very large air-cooled
commercial package air conditioning and heating equipment in
production and testing to enable DOE to review and make any
necessary adjustments to the specified confidence levels. See 80 FR
79655, 79659 (Dec. 23, 2015). However, DOE did not receive any
relevant data in response to that request.
---------------------------------------------------------------------------

2. Certification Reporting 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. In this NOPR, DOE is proposing changes to
certification reporting requirements to enable testing to the updated
industry test procedure AHRI 1230-2021 and to align with DOE's
proposals regarding determination of represented values for VRF multi-
split systems, discussed previously in section III.J.1. DOE is
proposing to amend the certification reporting requirements for VRF
multi-split systems to address the IEER metric but is not proposing
amendments to the current standards (in terms of EER). Therefore, the
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 unless DOE conducts a subsequent rulemaking amending the
standard to rely on the IEER metric.
a. Certification Requirements
In this NOPR, DOE proposes to amend the reporting requirements
consistent with the proposed amendments to the test procedure and
metric. When certifying a VRF multi-split system to standards in terms
of IEER, manufacturers would be required to report the following public
information in addition to the current certification requirements:
<bullet> IEER values (replacing the current certification
requirement for EER values).
<bullet> The rated heating capacity, in Btu/h.
<bullet> 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. This
proposal corresponds to the proposal regarding represented values for
indoor unit combinations discussed in section III.J.1.b of this NOPR.
<bullet> The refrigerant used to determine the represented values
for a basic model, per the proposal discussed in section III.J.1.c of
this NOPR that manufacturers must determine all represented values for
a basic model (e.g., EER, IEER, COP, and cooling capacity) based on the
refrigerant listed on the unit's nameplate that results in the lowest
cooling efficiency.
Regarding heating capacity, DOE is proposing to include rated
heating capacity in Btu/h (as measured according to the proposed
amended test procedure in Appendix D1) as a public reporting
requirement for all VRF multi-split heat pump systems (and not for VRF
multi-split air conditioners). DOE's current certification reporting
requirements for VRF multi-split systems at 10 CFR 429.43(b)(2) specify
that manufacturers must include the rated cooling capacity (in Btu/h)
and the rated cooling efficiency (EER, in Btu/W*h) in their public
certification reports. For VRF multi-split heat pumps, the public
certification report must also include the rated heating

[[Page 70666]]

efficiency (COP, in W/W), but the rated heating capacity is required to
be reported as part of the STI instead of in the public certification
report. DOE is proposing to require rated heating capacity as part of
the public certification report instead of the STI to align with the
certification approach for cooling capacity. As discussed in section
III.E.1, manufacturers already test and rate VRF multi-split systems in
the AHRI Directory of Certified Product Performance for VRF multi-split
systems.\23\ AHRI requires that manufactures publicly provide the rated
heating capacity of VRF multi-split systems at two separate outdoor
temperature conditions, including at the 47 [deg]F outdoor temperature
condition used in the proposed DOE test procedure. Because all VRF
multi-split system manufacturers are AHRI members, DOE tentatively
concludes that a requirement to report the rated heating capacity would
not increase the reporting burden.
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\23\ The AHRI directory for VRF multi-split systems is available
at: <a href="http://www.ahridirectory.org/NewSearch?programId=72&searchTypeId=3">www.ahridirectory.org/NewSearch?programId=72&searchTypeId=3</a>.
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Issue 12: DOE requests comment on its proposed certification
reporting requirements for VRF multi-split systems.
Manufacturers, including importers, must use product-specific
certification templates to certify compliance to DOE. For VRF multi-
split systems, the certification template reflects the general
certification requirements specified at 10 CFR 429.12 and the product-
specific public certification reporting requirements specified at Sec.
429.43(b)(2). DOE is proposing to amend the product-specific public
certification requirements for VRF multi-split systems in this notice.
To help interested parties better appreciate these proposed changes, a
draft certification template is included in the docket, which can be
viewed as described in the Docket section at the beginning of this
document and will be accessible on the DOE website.
b. Supplemental Testing Instructions
The STI generally provides equipment-specific instruction to allow
for third-party testing of equipment. DOE has tentatively determined
that updates in the industry test procedure AHRI 1230-2021 require
corresponding amendments to the STI certification requirements to test
VRF multi-split systems. DOE proposes to add or amend the following
items at Sec. 429.43(b)(4) as part of the required STI when certifying
a VRF multi-split system to amended standards in terms of IEER, as
these items would be needed for IEER testing per the proposed test
procedure at appendix D1:
<bullet> Identification of the indoor units to be thermally active
for each IEER test point;
<bullet> 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);
<bullet> 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);
<bullet> For water-cooled units, the rated water flow rate in
gallons per minute (gpm);
<bullet> System start-up or initialization procedures, including
conditions and durations;
<bullet> The duration of the compressor break-in period. (Existing
requirements in Sec. 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);
<bullet> Instructions for adjustment of critical parameters to meet
capacity targets and/or SHR limits, including hierarchy for adjusting;
<bullet> The layout of the system set-up for testing (previously
required upon request) including a piping diagram, setup instructions
for indoor units and outdoor units, charging instructions, a control
wiring diagram, and identification of the location of each critical
parameter;
<bullet> 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;
<bullet> Requiring testing instructions for conducting testing for
all indoor unit combinations with distinct represented values within a
basic model, as applicable. (This proposal corresponds to the proposal
regarding represented values for indoor unit combinations discussed in
section III.J.1.b of this NOPR);
<bullet> Removing the current requirement to report compressor
frequency set points 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;
<bullet> Removing the reporting requirement regarding whether the
model will operate at test conditions without manufacturer programming,
because the proposed VRF enforcement provisions (discussed in section
III.J of this NOPR) allow for a manufacturer representative to be on
site for DOE testing;
<bullet> Removing the reporting requirement for rated static
pressure, which is unnecessary because AHRI 1230-2021 includes ESP
requirements for testing; and
<bullet> The frequency of oil-recovery cycles.
Regarding the nominal cooling and heating capacity, DOE is also
proposing to clarify that manufacturers must certify the nominal
cooling capacity and nominal heating capacity (as applicable) for each
indoor unit and outdoor unit as a part of their supplemental testing
instructions. The existing STI requirements for VRF multi-split systems
require reporting of ``nominal cooling capacity'' and ``rated heating
capacity'', but do not specify whether these values need to be reported
for the entire VRF multi-split system or for each indoor and outdoor
unit. As described in section III.J.2.a, DOE is proposing to require
public reporting of rated heating capacity for VRF multi-split heat
pumps as part of the certification report. In sum, these proposals
would require that manufacturers publicly certify the rated cooling
capacity and rated heating capacity (as applicable) for each basic
model of VRF multi-split system, and then separately certify (in
supplemental testing instructions) the nominal cooling capacity and
nominal heating capacity (as applicable) for each indoor unit and
outdoor unit.
Regarding the CVP, DOE also proposes 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 set points to ensure control for 80 [deg]F dry-bulb
temperature when accounting for set point bias, the starting indoor
dry-bulb temperature, and the indoor dry-bulb temperature ramp rate.
This proposal corresponds to the proposal to adopt the CVP (as
specified in Appendix C of AHRI 1230-2021) in Sec. 429.134(s), as
discussed in section III.H of this NOPR.
Regarding specific components, as discussed in section III.G of
this NOPR, DOE is proposing an STI reporting requirement, corresponding
to the proposed representation requirements for specific components at
10 CFR 429.43(a)(4). Specifically DOE proposes that the manufacturer
must certify 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

[[Page 70667]]

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.
The proposed STI certification requirements provide information
that is necessary for testing VRF multi-split systems consistent with
the updated industry test procedure AHRI 1230-2021. Further, section D3
of informative appendix D of AHRI 1230-2021 includes a list of
recommended items to be included in STI when testing to AHRI 1230-2021,
and most of the STI certification requirements proposed in this NOPR
are included in the section D3 list. Therefore, DOE has tentatively
concluded that the proposed STI certification requirements are
warranted for testing according to the latest industry test procedure
for VRF-multi-split systems and would not impose significant burden to
manufacturers.
Issue 13: DOE requests comment on its proposed STI reporting
requirements for VRF multi-split systems.
3. Models Required for AEDM Validation
As discussed, manufacturers of VRF multi-split systems may
determine represented values through testing according to the sampling
plan in Sec. 429.43(a)(1), or by application of an AEDM as specified
in Sec. Sec. 429.43(a)(2) and 429.70. DOE proposes to adopt the
following AEDM validation requirements for VRF multi-split systems to
be similar to the sampling plan requirements for tested units,
discussed in section III.J.3 of this NOPR.
If a manufacturer makes 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 to which the AEDM
applies, DOE proposes that the manufacturer must validate the AEDM by
testing at least a single tested combination of that type of indoor
unit combination for each of the two selected basic models.
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 proposes 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. For example, if an AEDM is
validated through testing of two basic models (Model A and Model B) and
Model A and Model B both include ducted and non-ducted indoor unit
combinations, validation testing would need to be conducted on Model A
with a ducted tested combination and Model B with non-ducted tested
combination, or vice versa.
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 proposes 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. These proposals
retain DOE's existing requirements for VRF multi-split systems at Sec.
429.70(c)(iv) to test two basic models in order to validate an AEDM.
DOE has tentatively concluded that the proposed AEDM validation
requirements are consistent with AHRI 1230-2021, because they ensure
that values developed with an AEDM conform to the results of AHRI 1230-
2021. These proposals would only be required when certifying to amended
standards in terms of IEER.
Issue 14: DOE requests comment on its proposal to amend its
requirements for AEDM validation for VRF multi-split systems.
4. Manufacturer Involvement
DOE does not allow manufacturer involvement in assessment and
enforcement testing of most regulated equipment to ensure objectivity
and repeatability. However, in acknowledgement of the uniquely
complicated nature of VRF multi-split systems, the current DOE test
procedure includes allowances in Sec. 431.96(f) for limited
manufacturer involvement during assessment and enforcement testing. 77
FR 28927, 28946. Specifically, a manufacturer's representative is
allowed to witness assessment and enforcement testing, inspect set-up,
discuss set-up with a DOE representative, and adjust modulating
components to achieve steady-state operation. Sec. 431.96(f). In AHRI
1230-2021, allowable manufacturer involvement is prescribed in Sections
5.1.2 and 6.3.3.
Section 5.1.2 states that manufacturer authorized personnel may
support commissioning of the VRF multi-split system being tested (i.e.,
ensuring that the system is properly installed and functioning as
expected). Section 5.1.2.1 states that operational settings for
critical parameters may be manually adjusted and shall be as specified
in the STI but does not specify which party is responsible for setting
the critical parameters during testing. Section 5.1.2.2 states that all
compressors shall initially operate at the setting(s) provided in the
STI, which is redundant with Section 5.1.2.1. Section 5.1.2.3 states
that all control settings must be set by a member of the laboratory and
states that all control settings must remain unchanged for all load
points once system setup has been completed.
Section 6.3.3 specifies allowable critical parameter adjustments
for the purposes of meeting capacity targets and/or SHR limits during
IEER cooling tests. However, Section 6.3.3 includes unclear and
contradictory language regarding who performs critical parameter
adjustments. Specifically, Section 6.3.3 describes critical parameter
``adjustments'' as being performed by laboratory personnel, but also
specifies that when a steady-state test is conducted in a third-party
laboratory, a manufacturer's representative may ``set'' critical
parameter values under the supervision of the third-party laboratory
(using the service tool to monitor critical parameters). Further,
Section 6.3.3 uses several different terms when describing who takes
certain actions as part of adjusting critical parameters, for which it
is unclear if any difference in meaning is intended: ``the lab'', ``a
member of the laboratory'', ``lab personnel'', and ``the third party
laboratory''.
Given the importance of explicitly specifying the specific actions
the manufacturer's representative can take as part of assessment and
enforcement testing of VRF multi-split systems, DOE does not propose to
adopt Sections 5.1.2 and 6.3.3 of AHRI 1230-2021, and instead proposes
to specify in Sec. 429.134(s)(2) provisions for allowable manufacturer
involvement during DOE assessment and enforcement testing. These
provisions are generally consistent with Sections 5.1.2 and 6.3.3 of
AHRI 1230-2021, but assign more

[[Page 70668]]

precisely the actions that a manufacturer's representative may take.
Specifically, DOE is proposing to clarify that a manufacturer's
representative is allowed to support commissioning of the VRF multi-
split system and to witness DOE assessment or enforcement testing,
which is consistent with the current Federal test procedure. For all
cooling and heating tests, DOE proposes that all control settings other
than critical parameters must be set by a member of the third-party
laboratory; a manufacturer's representative may initially set all
critical parameters to their certified values. For IEER cooling tests
only, DOE proposes to specify that if additional adjustments to
critical parameters are required for meeting capacity targets and/or
SHR limits (see section III.I of this NOPR), a manufacturer's
representative may make such adjustments in accordance with section 5.1
of appendix D1 using a proprietary control tool. DOE further proposes
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.
For the heating test, DOE proposes 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. These proposals are a
departure from the current DOE test procedure (which allows
manufacturer control of modulating components for the purposes of
reaching steady-state operation) and instead align with the latest
industry test procedure AHRI 1230-2021 (with minor clarifications in
wording, as discussed).
In the case that a manufacturer is not present for assessment or
enforcement testing, third-party laboratory personnel may need a
manufacturer's control tool to set critical parameters to their initial
settings or make additional adjustments required by the test procedure.
Accordingly, DOE is proposing to amend its test notice requirements for
VRF multi-split systems at Sec. 429.110(b)(1)(iv) to require
manufacturers to include a means of control to set and adjust critical
parameters with all systems provided for enforcement testing.
Correspondingly, DOE is proposing provisions for VRF multi-split
systems at Sec. 429.104(b) that would require manufacturers to provide
a means of control for assessment testing, although manufacturers would
not be required to provide the VRF multi-split system for assessment
testing. This proposal would enable the laboratory staff to perform
IEER and heating tests in the event that a manufacturer's
representative is not available for assessment and/or enforcement
testing. DOE also proposes that, if a manufacturer's representative is
not present for testing, a member of the third-party laboratory shall
set and adjust critical parameter values in accordance with section 5.1
of appendix D1 using the means of control provided by the manufacturer
in response to the test notice.
Issue 15: DOE seeks comment on its proposal to require a means of
control to be provided by the manufacturer for assessment and
enforcement testing.
Furthermore, AHRI 1230-2021 only partially addresses allowable
manufacturer involvement during the CVP. Specifically, section C3.1
provides instructions that control settings must be identical to those
used during the steady-state IEER tests, except that control settings
for critical parameters shall not be controlled during the CVP.
However, Appendix C to AHRI 1230-2021 does not provide instruction for
which parties may interact with the unit under test, and under what
circumstances. Also, the wording ``identical to those used during the
steady-state IEER tests'' could be interpreted to mean that steady-
state IEER tests must be conducted prior to a CVP, which should not be
necessary. To address these issues, DOE proposes to specify in its
product-specific enforcement provisions at Sec. 429.134(s)(2) that a
manufacturer's representative is allowed to support commissioning of
the VRF multi-split system and witness the CVP. DOE also proposes to
specify that the control settings used during a CVP must be set by a
member of the third-party laboratory and must be set per the provisions
in section 5.1 of appendix D1 to subpart F of part 431 (except for
critical parameters, which must operate automatically from the system
controls and must not be controlled or adjusted at any point during the
CVP).
DOE has tentatively concluded that these proposals would ensure the
consistency and objectivity of the CVP. Furthermore, these proposals
are consistent with AHRI 1230-2021, because they ensure the
manufacturer's representative cannot set or adjust any parameters in
the CVP that AHRI 1230-2021 specifies shall operate under commands from
system controls during the CVP. Additionally, the proposed language to
set control settings for the CVP (except critical parameters) in
accordance with section 5.1 of appendix D1 to subpart F of part 431
ensures that the same control settings (except critical parameters) are
used between the CVP and IEER cooling tests, without requiring IEER
cooling tests to be conducted before a CVP.
Issue 16: DOE seeks comment on its proposal to establish in 10 CFR
429.134(s)(2) provisions regarding allowable manufacturer involvement
during assessment and enforcement testing, which are consistent with
AHRI 1230-2021. DOE also seeks comment on its proposal for allowable
manufacturer involvement during the CVP.
5. Certified Critical Parameter Operational Settings
As described in section III.J.2.b of this NOPR, DOE is proposing to
require that manufacturers certify in the STI the 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. Because
the control settings for critical parameters affect the operating state
of the VRF multi-split system, the measured performance is likely to
vary significantly based on the critical parameter settings selected.
For example, in preliminary testing, DOE determined that a 10 percent
change in compressor speed resulted in an average difference of
approximately 5 EER points (in Btu/W*hr) at each IEER load point.
(EERE-2018-BT-STD-0003-0063 at p. 15). Due to the relationship of
critical parameter operational settings to the measured performance of
VRF multi-split systems, DOE is making several proposals related to the
certified critical parameters.
As discussed in section III.H.5, DOE is proposing to use the CVP
during assessment and enforcement testing to verify that the certified
critical parameter values for IEER cooling tests are valid. The
certified critical parameter values used for the heating test are not
subject to validation from a CVP, as the CVP is applicable only for
cooling operation. In addition to its proposals governing the use of
the CVP, DOE is proposing to add a certification reporting provision
specific to VRF multi-split systems in Sec. 429.43(b)(5). This
proposal specifies that if a manufacturer becomes aware that any of the
certified operational settings for the critical parameters are
determined to be invalid according to the results of a CVP, whether
that CVP be performed by the manufacturer or another party, the
manufacturer would be required to re-certify the operational settings
of those critical parameters for all affected basic models, as well as
re-rate and re-certify the affected basic models. Notably, DOE is not
proposing a requirement that

[[Page 70669]]

manufacturers conduct the CVP as part of certification to DOE.
In addition to its proposal to require re-certification and re-
rating of VRF multi-split systems in the event a manufacturer becomes
aware that any of its certified operational settings for critical
parameters are invalid according to a CVP, DOE also proposes to amend
the enforcement testing requirements at Sec. 429.110(a) to state that
DOE may initiate enforcement testing for VRF multi-split systems if DOE
has reason to believe that the model is not in compliance, has invalid
certified operational settings for critical parameter values, or has an
otherwise invalid certified rating. Under this proposal DOE may
initiate enforcement testing to investigate the certified critical
parameter values and the associated IEER rating for VRF multi-split
systems based on any of the following events:
1. DOE conducts CVP during assessment testing that results in
invalidated operational settings for critical parameters for a basic
model;
2. DOE conducts assessment testing for IEER and COP that creates
reason to believe the basic model would be non-compliant with energy
conservation standards or have an otherwise invalid rating;
3. Another party conducts a CVP that results in invalidated
operational settings for critical parameters for a basic model and the
manufacturer fails to recertify that basic model;
4. A CVP is conducted (by DOE or another party) that results in
invalidated operational settings for critical parameters for a basic
model, and DOE finds that a similar basic model from the same
manufacturer relies on similar certified operational settings for
critical parameters.
DOE may examine multiple sources including, but not limited to,
publicly available information and the STI when determining whether
there is reason to proceed to enforcement testing. DOE notes that upon
initiation of enforcement testing, DOE will issue a test notice to the
manufacturer to acquire the selected models and means of control, and
will conduct a CVP on the certified operational settings of critical
parameters before proceeding to IEER testing.
Issue 17: DOE requests comment on its proposed approaches for
certification and for enforcement testing in the event that a VRF
multi-split system has invalid certified operational settings for
critical parameter values.
6. Enforcement Sampling Plan
DOE's regulations at Sec. 429.110(e) include provisions for
selection of units for enforcement testing. Specifically, Sec.
429.110(e)(2) states that for commercial air conditioners and heat
pumps (which includes VRF multi-split systems), DOE will use an initial
sample size of not more than four (4) units when determining a basic
model's compliance with applicable energy conservation standards. As
described in section III.J.1.b of this NOPR, DOE has tentatively
determined that the testing of VRF multi-split systems is significantly
more involved than the testing of other commercial HVAC equipment. The
proposed test procedure would incorporate instructions for setting the
positions of multiple critical parameters during testing, which
requires additional setup as compared to other kinds of commercial HVAC
equipment. DOE estimates the cost to test VRF multi-split systems to be
between $7,500 and $27,000, depending on size and configuration of the
system (not including costs of copper piping or refrigerant).
Additionally, DOE is proposing in this NOPR to incorporate the CVP into
its enforcement regulations for VRF multi-split systems at Sec.
429.134(s), which would add approximately eight hours of test time at
each of the four IEER load conditions during enforcement testing.
Because of the involved nature of testing VRF multi-split systems,
it would be unlikely that DOE would conduct assessment testing or
enforcement testing on the maximum number of units currently specified
(i.e., four). In order to reflect what would be the expected practice,
DOE proposes to amend its enforcement sampling plan requirements
specific to VRF multi-split systems to require a sample size of two VRF
multi-split systems. The process for determining compliance with energy
conservation standards would be unchanged in this proposal, i.e., a
compliance determination would be made for VRF multi-split systems
using the sampling plan found in appendix B to subpart C of part 429
with a first sample size of n<INF>1</INF> = 2 VRF multi-split systems.
Issue 18: DOE requests comment on its proposed enforcement sampling
plan for VRF multi-split systems.

K. Test Procedure Costs

EPCA requires that the test procedures for commercial package air
conditioning and heating equipment, which includes VRF multi-split
systems, be those generally accepted industry testing procedures or
rating procedures developed or recognized by AHRI or by ASHRAE, as
referenced in 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 rule published in the Federal Register and
supported by clear and convincing evidence, that such amended test
procedure would not meet the requirements in 42 U.S.C. 6314(a)(2) and
(3) related to representative use and test burden. (42 U.S.C.
6314(a)(4)(B)) In this NOPR, DOE proposes to amend the current test
procedure for VRF multi-split systems at Sec. 431.96 by (1)
incorporating by reference AHRI 1230-2021 and ANSI/ASHRAE 37-2009; and
(2) establishing provisions for determining IEER for VRF multi-split
systems. DOE also proposes to amend 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.
Most significantly, these proposed changes include the incorporation of
the CVP from AHRI 1230-2021 into DOE's product-specific enforcement
provisions at Sec. 429.134, as well as accompanying certification
requirements at Sec. 429.43.
DOE has tentatively determined that these proposed amended test
procedures would be representative of an average use cycle and would
not be unduly burdensome for manufacturers to conduct. The proposed
appendix D, measuring EER and COP per ANSI/AHRI 1230-2010, does not
contain any changes from the current Federal test procedure, and,
therefore, would not require retesting solely as a result of DOE's
adoption of this proposed amendment to the test procedure, if made
final. The proposed test procedure in appendix D1, measuring IEER and
COP per AHRI 1230-2021, would lead to an increase in cost from appendix
D testing. DOE estimates that the cost for third-party lab testing
according to the proposed appendix D1 for measuring IEER and COP to be
$7,500--$27,000 per VRF multi-split heat pump system, depending on size
and configuration.
As discussed in section II, the proposed test procedure provisions
regarding IEER would not be mandatory unless DOE amends the energy
conservation standards for VRF multi-split systems based on IEER. But,
DOE has tentatively determined that the proposed test procedure
amendments would not be expected to increase the testing burden on VRF
multi-split

[[Page 70670]]

system manufacturers. All VRF multi-split system manufacturers are AHRI
members; DOE is referencing the prevailing industry test procedure that
was established for use in AHRI's certification program (which DOE
presumes will be updated to include IEER in terms of the latest
industry test procedure AHRI 1230-2021). Therefore, DOE expects that
manufacturers will begin testing using the test methods in AHRI 1230-
2021, and the testing burden will already be incurred from AHRI members
participating in AHRI's certification program. Additionally, DOE has
tentatively determined that the test procedure amendments, if
finalized, would not require manufacturers to redesign any of the
covered equipment, would not require changes to how the equipment is
manufactured, and would not impact the utility of the equipment.
Issue 19: DOE requests comment on its understanding of the impact
of the test procedure proposals in this NOPR, specifically DOE's
initial conclusion that the proposed DOE test procedure amendments, if
finalized, would not increase testing burden on VRF multi-split system
manufacturers, compared to current industry practice as indicated by
AHRI 1230-2021.

L. Reserved Appendices for Test Procedures for Commercial Air
Conditioning and Heating Equipment

DOE is proposing to relocate and centralize the current test
procedures for VRF multi-split systems to a new appendix D to subpart F
of part 431. As proposed, appendix D would not amend the current test
procedures. Appendix D would continue to reference ANSI/AHRI 1230-2010
and provide instructions for determining EER and COP. Correspondingly,
DOE is proposing to update the existing incorporation by reference of
ANSI/AHRI 1230-2010 at Sec. 431.95 so that the incorporation by
reference applies to appendix D. Appendix D would also centralize the
additional test provisions currently applicable under Sec. 431.96--
Sec. 431.96(c) through (f). VRF multi-split systems would be required
to be tested according to appendix D, absent amendments to the
applicable energy conservation standards to rely on the IEER metric.
DOE also proposes to adopt the updated version of AHRI 1230, AHRI
1230-2021, including the IEER metric in a new appendix D1 to subpart F
of part 431. VRF multi-split systems would not be required to test
according to appendix D1 until compliance is required with amended
energy conservation standards that rely on the IEER metric, should DOE
adopt such standards.

M. Compliance Date

EPCA prescribes that, if DOE amends a test procedure, all
representations of energy efficiency and energy use, including those
made in the context of certification and on marketing materials and
product labels, must be made in accordance with that amended test
procedure, beginning 360 days after publication of such a test
procedure final rule in the Federal Register. (42 U.S.C. 6314(d)(1))
EPCA also provid

[…truncated; see source link]

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