36018 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

DEPARTMENT OF ENERGY 

10 CFR Parts 429 and 431 

[EERE–2017–BT–TP–0018] 

RIN 1904–AD93 

Energy Conservation Program: Test 

Procedure for Dehumidifying Direct 

Expansion-Dedicated Outdoor Air 

Systems 

AGENCY: Office of Energy Efficiency and 

Renewable Energy, Department of 

Energy. 

ACTION: Notice of proposed rulemaking 

and request for comment. 

SUMMARY: The U.S. Department of 

Energy (DOE) is proposing to establish 

definitions for ‘‘direct expansiondedicated outdoor air systems’’ (DX– 

DOAS or DX–DOASes) and 

‘‘dehumidifying direct expansiondedicated outdoor air systems’’ (DDX– 

DOAS or DDX–DOASes). DX–DOASes 

are a category of small, large, and very 

large commercial package air 

conditioning and heating equipment 

under the Energy Policy and 

Conservation Act (EPCA), as amended. 

In addition, DOE is proposing to 

establish a test procedure to measure the 

energy efficiency of DDX–DOASes, 

which aligns with the most recent 

version of the relevant industry 

consensus test standards for DDX– 

DOASes, with certain minor 

modifications. Lastly, DOE is proposing 

to add supporting definitions, energy 

efficiency metrics for dehumidification 

and heating modes, and provisions 

governing public representations as part 

of this rulemaking. 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 September 7, 2021. See section V, 

‘‘Public Participation,’’ for details. 

Meeting: DOE will hold a webinar on 

Monday, August 2, 2021 from 10:00 a.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 

www.regulations.gov. Follow the 

instructions for submitting comments. 

Alternatively, interested persons may 

submit comments, identified by docket 

number EERE–2017–BT–TP–0018, by 

any of the following methods: 

1. Federal eRulemaking Portal: 

www.regulations.gov. 

2. Email: to CommACHeatingEquip

Cat2017TP0018@ee.doe.gov. Include 

docket number EERE–2017–BT–TP– 

0018 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 postal 

mail and hand delivery/courier, the 

Department has found it necessary to 

make temporary modifications to the 

comment submission process in light of 

the ongoing Covid–19 pandemic. DOE is 

currently accepting only electronic 

submissions at this time. If a commenter 

finds that this change poses an undue 

hardship, please contact Appliance 

Standards Program staff at (202) 586– 

1445 to discuss the need for alternative 

arrangements. Once the Covid–19 

pandemic health emergency is resolved, 

DOE anticipates resuming all of its 

regular options for public comment 

submission, including postal mail and 

hand delivery/courier. 

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 

www.regulations.gov. All documents in 

the docket are listed in the 

www.regulations.gov index. However, 

some documents listed in the index, 

such as those containing information 

that is exempt from public disclosure, 

may not be publicly available. 

The docket web page can be found at: 

www.regulations.gov/ 

#docketDetail;D=EERE-2017-BT-TP0018. 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 

www.regulations.gov. 

FOR FURTHER INFORMATION CONTACT: Ms. 

Catherine Rivest, U.S. Department of 

Energy, Office of Energy Efficiency and 

Renewable Energy, Building 

Technologies Office, EE–5B, 1000 

Independence Avenue SW, Washington, 

DC, 20585–0121. Telephone: (202) 586– 

7335. Email: ApplianceStandards

Questions@ee.doe.gov. 

Mr. Eric Stas, U.S. Department of 

Energy, Office of the General Counsel, 

GC–33, 1000 Independence Avenue SW, 

Washington, DC 20585. Telephone: 

(202) 586–5827. Email: Eric.Stas@

hq.doe.gov. 

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: 

ApplianceStandardsQuestions@

ee.doe.gov. 

SUPPLEMENTARY INFORMATION: DOE 

proposes to incorporate by reference the 

following industry standards into title 

10 of the Code of Federal Regulations 

(CFR) part 431: 

Air-Conditioning, Heating, and 

Refrigeration Institute (AHRI) 

Standard 920–2020 (I–P), ‘‘2020 

Standard for Performance Rating of 

Direct Expansion-Dedicated Outdoor 

Air System Units,’’ approved 

February 4, 2020. 

American National Standards Institute 

(ANSI)/AHRI Standard 1060–2018, 

‘‘2018 Standard for Performance 

Rating of Air-to-Air Exchangers for 

Energy Recovery Ventilation 

Equipment,’’ approved 2018. 

Copies of AHRI Standard 920–2020 

(I–P), and ANSI/AHRI Standard 1060– 

2018 can be obtained from the Airconditioning, Heating, and Refrigeration 

Institute, 2311 Wilson Blvd., Suite 400, 

Arlington, VA 22201, (703) 524–8800, or 

online at: www.ahrinet.org. 

ANSI/American Society of Heating, 

Refrigerating and Air-Conditioning 

Engineers (ASHRAE) Standard 37– 

2009, ‘‘Methods of Testing for Rating 

Electrically Driven Unitary AirConditioning and Heat Pump 

Equipment,’’ ASHRAE approved June 

24, 2009. 

ANSI/ASHRAE Standard 41.1–2013, 

‘‘Standard Method for Temperature 

Measurement,’’ ANSI approved 

January 30, 2013. 

ANSI/ASHRAE Standard 41.6–2014, 

‘‘Standard Method for Humidity 

Measurement,’’ ANSI approved July 3, 

2014. 

ANSI/ASHRAE Standard 198–2013, 

‘‘Method of Test for Rating DXDedicated Outdoor Air Systems for 

Moisture Removal Capacity and 

Moisture Removal Efficiency,’’ ANSI 

approved January 30, 2013. 

Copies of ANSI/ASHRAE Standard 

37–2009, ANSI/ASHRAE Standard 

41.1–2013, ANSI/ASHRAE Standard 

41.6–2014, and ANSI/ASHRAE 

Standard 198–2013 can be obtained 

from the American Society of Heating, 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36019 

1See American Society of Heating, Refrigerating 

and Air-Conditioning Engineers (ASHRAE) 

Standard 90.1, ‘‘Energy Standard for Buildings 

Except Low-Rise Residential Buildings.’’ 

2Other types of dedicated outdoor air systems are 

available that do not utilize direct expansion (e.g., 

units that use chilled water, rather than refrigerant, 

as the heat transfer medium); these are discussed 

in section III.B.3.e.v. of this document. 

3All 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). 

4For editorial reasons, upon codification in the 

U.S. Code, Part C was redesignated Part A–1. 

Refrigerating and Air-Conditioning 

Engineers, 180 Technology Parkway, 

Peachtree Corners, GA 30092, (404) 

636–8400, or online at: www.ashrae.org. 

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 

1. Equipment Coverage 

2. Scope of Test Procedure 

3. Capacity Limit 

4. Industry Terminology 

B. Test Procedure for Dehumidifying 

Dedicated Outdoor Air Systems 

1. Industry Consensus Test Standards 

2. Efficiency Metrics 

a. Dehumidification Metric 

b. Heating Metric 

c. ISMRE2 and ISCOP2 Weighting Factors 

3. Test Method 

a. Definitions 

b. Break-In Period 

c. Airflow-Measuring Apparatus 

d. Test Operating Conditions 

i. Target Supply and Return Airflow Rates 

ii. Units With Cycle Reheat Functions 

iii. Target Supply Air Dry-Bulb 

Temperature 

iv. Target Supply Air Dew-Point 

Temperature 

v. Units With Staged Capacity Control 

e. Water-Cooled and Water-Source Heat 

Pump DX–DOAS Equipment 

i. Test Conditions for Multiple-Inlet Water 

Sources 

ii. Condenser Liquid Flow Rate 

iii. Water Pump Effect 

iv. Energy Consumption of Heat Rejection 

Fans and Chillers 

v. Chilled Water Coil Exclusion 

f. Defrost Energy Use for Air-Source Heat 

Pump 

g. General Control Setting Requirements 

h. Ventilation Energy Recovery Systems 

i. Exhaust Air Transfer and Leakage 

ii. Purge Angle Setting 

iii. Return Air External Static Pressure 

Requirements 

iv. Target Return Airflow Rate 

i. Demand-Controlled Ventilation 

j. Tolerances for Supply and Return 

Airflow and External Static Pressure 

k. Secondary Dehumidification and 

Heating Capacity Tests 

l. Corrections 

i. Calculation of the Degradation 

Coefficient 

ii. Non-Standard Low-Static Motor 

iii. Calculation of Supplementary Heat 

Penalty 

4. Determination of Represented Values 

a. Basic Model 

b. Sampling Plan Requirements 

c. Multiple Refrigerants 

d. Alternative Energy-Efficiency 

Determination Methods 

e. Rounding 

5. Configuration of Unit Under Test 

C. Other Comments 

D. Test Procedure Costs, Harmonization, 

and Other Topics 

1. Test Procedure Costs and Impact 

2. Harmonization With Industry Standards 

3. Other Test Procedure Topics 

E. 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 

Small, large, and very large 

commercial package air conditioning 

and heating equipment are included in 

the list of ‘‘covered equipment’’ for 

which DOE is authorized to establish 

and amend energy conservation 

standards and test procedures. (42 

U.S.C. 6311(1)(B)–(D)) As defined by the 

Energy Policy and Conservation Act, as 

amended (EPCA), ‘‘commercial package 

air conditioning and heating 

equipment’’ means air-cooled, watercooled, evaporatively-cooled, or watersource (not including ground-watersource) electrically operated, unitary 

central air conditioners and central air 

conditioning heat pumps for 

commercial application. (42 U.S.C. 

6311(8)(A)) Industry standards generally 

describe unitary central air conditioning 

equipment as one or more factory-made 

assemblies that normally include an 

evaporator or cooling coil and a 

compressor and condenser combination. 

Units equipped to also perform a 

heating function are included as well.1

Direct expansion-dedicated outdoor air 

systems (DX–DOASes) provide 

conditioning of outdoor ventilation air 

using a refrigeration cycle consisting of 

a compressor, condenser, expansion 

valve, and evaporator,2 and therefore, 

DOE has initially concluded that DX– 

DOASes are a category of commercial 

package air conditioning and heating 

equipment subject to EPCA. An industry 

consensus test standard has been 

established for a subset of DX–DOASes 

(i.e., dehumidifying DX–DOASes (DDX– 

DOASes)), which are the subject of this 

test procedure proposal. The following 

sections discuss DOE’s authority to 

establish test procedures for DDX– 

DOASes, as well as relevant background 

information regarding DOE’s proposed 

adoption of the industry consensus test 

standard, and proposed clarifications to 

the industry test procedure for this 

equipment. 

A. Authority 

EPCA,3 as amended, among other 

things, authorizes DOE to regulate the 

energy efficiency of a number of 

consumer products and certain 

industrial equipment. Title III, Part C4

of EPCA, Public Law 94–163 (42 U.S.C. 

6311–6317, as codified), added by 

Public Law 95–619, Title IV, § 441(a), 

established the Energy Conservation 

Program for Certain Industrial 

Equipment, which sets forth a variety of 

provisions designed to improve energy 

efficiency. This covered equipment 

includes small, large, and very large 

commercial package air conditioning 

and heating equipment. (42 U.S.C. 

6311(1)(B)–(D)) DOE has initially 

determined that commercial package air 

conditioning and heating equipment 

includes DX–DOASes. As discussed in 

section I.B of this document, DX– 

DOASes had not previously been 

addressed in DOE rulemakings and are 

not currently subject to Federal test 

procedures or energy conservation 

standards. 

Under EPCA, DOE’s energy 

conservation program consists 

essentially of four parts: (1) Testing, (2) 

labeling, (3) Federal energy conservation 

standards, and (4) certification and 

enforcement procedures. Relevant 

provisions of EPCA specifically include 

definitions (42 U.S.C. 6311), energy 

conservation standards (42 U.S.C. 6313), 

test procedures (42 U.S.C. 6314), 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36020 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

5From the June 2018 ASHRAE eSociety 

Newsletter (Available at: www.ashrae.org/news/ 

esociety/what-s-new-in-doas-and-refrigerantresearch) (Last accessed May 24, 2021). 

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 in limited circumstances for 

particular State laws or regulations, in 

accordance with the procedures and 

other provisions of EPCA. (42 U.S.C. 

6316(b)(2)(D)) 

Under 42 U.S.C. 6314, the statute also 

sets forth the criteria and procedures 

DOE is required to follow when 

prescribing or amending test procedures 

for covered equipment. Specifically, 

EPCA requires that any test procedure 

prescribed or amended shall be 

reasonably designed to produce test 

results which measure energy 

efficiency, energy use, or estimated 

annual operating cost of covered 

equipment during a representative 

average use cycle and requires that test 

procedures not be unduly burdensome 

to conduct. (42 U.S.C. 6314(a)(2)) 

EPCA requires that the test 

procedures for commercial package air 

conditioning and heating equipment be 

those generally accepted industry 

testing procedures or rating procedures 

developed or recognized by the AirConditioning, Heating, and Refrigeration 

Institute (AHRI) or by the American 

Society of Heating, Refrigerating and 

Air-Conditioning Engineers (ASHRAE), 

as referenced in ASHRAE Standard 

90.1, ‘‘Energy Standard for Buildings 

Except Low-Rise Residential Buildings’’ 

(ASHRAE Standard 90.1). (42 U.S.C. 

6314(a)(4)(A)) Further, if such an 

industry test procedure is amended, 

DOE must update its test procedure to 

be consistent with the amended 

industry test procedure, unless DOE 

determines, by rule published in the 

Federal Register and supported by clear 

and convincing evidence, that 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)) 

EPCA also requires that, at least once 

every seven years, DOE evaluate test 

procedures for each type of covered 

equipment, including commercial 

package air conditioning and heating 

equipment to determine whether 

amended test procedures would more 

accurately or fully comply with the 

requirements for the test procedures not 

to be unduly burdensome to conduct 

and be reasonably designed to produce 

test results that reflect energy efficiency, 

energy use, and estimated operating 

costs during a representative average 

use cycle. (42 U.S.C. 6314(a)(1)–(3)) In 

addition, if DOE determines that a test 

procedure amendment is warranted, it 

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)) 

As discussed in section I.B of this 

document, a test procedure for a subset 

of DX–DOASes (i.e., DDX–DOASes), 

was first specified by ASHRAE Standard 

90.1 in the 2016 edition (ASHRAE 

Standard 90.1–2016). Pursuant to 42 

U.S.C. 6314(a)(4)(B), and following 

updates to the relevant test procedures 

which were referenced in ASHRAE 

Standard 90.1, DOE is publishing this 

NOPR proposing to establish a test 

procedure for DDX–DOASes in 

satisfaction of its aforementioned 

obligations under EPCA. 

B. Background 

From a functional perspective, DX– 

DOASes operate similarly to other 

categories of commercial package air 

conditioning and heat pump equipment, 

in that they provide conditioning using 

a refrigeration cycle consisting of a 

compressor, condenser, expansion 

valve, and evaporator. DX–DOASes 

provide ventilation and conditioning of 

100-percent outdoor air to the 

conditioned space, whereas for typical 

commercial package air conditioners 

that are central air conditioners, outdoor 

air makes up only a small portion of the 

total airflow (usually less than 50 

percent). DX–DOASes are typically 

installed in addition to a local, primary 

cooling or heating system (e.g., 

commercial unitary air conditioner, 

variable refrigerant flow system, chilled 

water system, water-source heat 

pumps)—the DX–DOAS conditions the 

outdoor ventilation air, while the 

primary system provides cooling or 

heating to balance building shell and 

interior loads and solar heat gain. 

According to ASHRAE, a well-designed 

system using a DX–DOAS can ventilate 

a building at lower installed cost, 

reduce overall annual building energy 

use, and improve indoor environmental 

quality.5

On October 26, 2016, ASHRAE 

published ASHRAE Standard 90.1– 

2016, which for the first time specified 

a test standard and efficiency standards 

for DX–DOASes. ASHRAE Standard 

90.1–2016 (and the subsequent 2019 

edition) defines DX–DOAS as a type of 

air-cooled, water-cooled, or watersource factory assembled product that 

dehumidifies 100% outdoor air to a low 

dew point and includes reheat that is 

capable of controlling the supply drybulb temperature of the dehumidified 

air to the designed supply air 

temperature. This conditioned outdoor 

air is then delivered directly or 

indirectly to the conditioned spaces. It 

may precondition outdoor air by 

containing an enthalpy wheel, sensible 

wheel, desiccant wheel, plate heat 

exchanger, heat pipes, or other heat or 

mass transfer apparatus. 

Although ASHRAE Standard 90.1– 

2016 uses the term ‘‘DX–DOAS,’’ the 

definition of this term provided therein 

describes a subset of DX–DOASes, 

specifically DDX–DOASes. The 

ASHRAE definition of ‘‘DX–DOAS’’ is 

generally equivalent to the equipment 

DOE is proposing to define as DDX– 

DOAS and for which DOE is proposing 

to adopt the industry consensus 

standard. DDX–DOASes dehumidify air 

to a low dew point. When operating in 

humid conditions, the dehumidification 

load from the outdoor ventilation air is 

a much larger percentage of the total 

cooling load for a DDX–DOAS than for 

a typical commercial air conditioner. 

Additionally, compared to a typical 

commercial air conditioner, the amount 

of total cooling (both sensible and 

latent) is much greater per pound of air 

for a DDX–DOAS at design conditions 

(i.e., the warmest/most humid expected 

summer conditions), and a DDX–DOAS 

is designed to accommodate greater 

variation in entering air temperature 

and humidity (i.e., a typical commercial 

air conditioner would not be able to 

dehumidify 100-percent outdoor 

ventilation air to the levels achieved by 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36021 

6 In the July 2017 ASHRAE TP RFI, DOE referred 

to DDX–DOASes simply as ‘‘DOASes.’’ 

a DDX–DOAS). Not all DX–DOASes 

have this dehumidification capability, 

which is why DOE is proposing a 

separate definition. (See section III.B.2.a 

of this NOPR for further details.) 

The amendment to ASHRAE Standard 

90.1 to specify an industry test standard 

for equipment that DOE calls DDX– 

DOAS triggered DOE’s obligations vis-a`- 

vis test procedures under 42 U.S.C. 

6314(a)(4)(B), as outlined previously. 

On July 25, 2017, DOE published a 

request for information (RFI) (the July 

2017 ASHRAE TP RFI) in the Federal 

Register to collect information and data 

to consider new and amended DOE test 

procedures for commercial package air 

conditioning and heating equipment, 

given 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 several aspects regarding 

test procedures for DDX–DOASes in 

consideration of adopting a new DOE 

test procedure for this equipment, 

including: Incorporation by reference of 

the relevant industry test standard(s); 

efficiency metrics and calculations, and 

additional topics that may inform DOE’s 

decisions in a future test procedure 

rulemaking.6 82 FR 34427, 34435–34439 

(July 25, 2017). On October 25, 2019, 

ASHRAE published an updated version 

of ASHRAE Standard 90.1 (i.e., 

ASHRAE Standards 90.1–2019), which 

maintained the DDX–DOAS provisions 

as first introduced in ASHRAE Standard 

90.1–2016 without revisions. 

DOE received a number of comments 

from interested parties in response to 

the July 2017 ASHRAE TP RFI, which 

covered multiple categories of 

equipment. Table I–1 lists the 

commenters relevant to DDX–DOASes, 

along with each commenter’s 

abbreviated name used throughout this 

NOPR. DOE considered these comments 

in the preparation of 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 DX–DOAS-RELATED COMMENTS ON THE JULY 2017 ASHRAE TEST

PROCEDURE RFI 

Name Abbreviation Type 1

Air-Conditioning, Heating, and Refrigeration Institute ............................................................................. AHRI ............................................ IR 

Appliance Standards Awareness Project (ASAP), Alliance to Save Energy (ASE), American Council 

for an Energy-Efficient Economy (ACEEE), Northwest Energy Efficiency Alliance (NEEA), and 

Northwest Power and Conservation Council (NPCC).

Joint Advocates ........................... EA 

Carrier Corporation, part of United Technologies Climate, Controls & Security (CCS) business .......... Carrier ......................................... M 

Goodman Global, Inc .............................................................................................................................. Goodman ..................................... M 

The Greenheck Group ............................................................................................................................. Greenheck ................................... M 

Ingersoll Rand ......................................................................................................................................... Ingersoll Rand ............................. M 

Lennox International, Inc ......................................................................................................................... Lennox ......................................... M 

Mitsubishi Electric Cooling & Heating 2 ................................................................................................... Mitsubishi .................................... M 

National Comfort Institute ........................................................................................................................ NCI .............................................. IR 

Pacific Gas and Electric Company (PG&E), Southern California Gas Company (SoCalGas), San 

Diego Gas and Electric (SDG&E), and Southern California Edison (SCE), collectively referred to 

as California Investor-Owned Utilities (CA IOUs).

CA IOUs ...................................... U 

1EA: Efficiency/Environmental Advocate; IR: Industry Representative; M: Manufacturer; U: Utility. 

2 Mitsubishi commented that it fully supports all of the comments submitted by AHRI on DX–DOAS issues. 

On February 14, 2020, DOE published 

a final rule updating its procedures for 

consideration of new and amended 

energy conservation standards at 10 CFR 

part 430, subpart C, appendix A, 

‘‘Procedures, Interpretations, and 

Policies for Consideration of New or 

Revised Energy Conservation Standards 

and Test Procedures for Consumer 

Products and Certain Commercial/ 

Industrial Equipment’’ (the Process 

Rule). 85 FR 8626. As part of the update, 

the Process Rule now applies explicitly 

to commercial and industrial 

equipment. 10 CFR 431.4. The updated 

Process Rule also includes provisions 

specific to the consideration of new and 

amended energy conservation standards 

and test procedures for covered 

equipment subject to the ASHRAE 

provisions of EPCA. See Process Rule, 

10 CFR part 430, subpart C, appendix A, 

sections 2 and 9. 

With respect to DOE’s consideration 

of changes to the relevant industry 

consensus test procedure(s) for covered 

ASHRAE equipment, the Process Rule 

now provides that DOE will do so only 

if it can meet a very high bar to 

demonstrate the ‘‘clear and convincing 

evidence’’ threshold. 10 CFR part 430, 

subpart C, appendix A, section 9(b). 

Clear and convincing evidence would 

exist only where the specific facts and 

data made available to DOE regarding a 

particular ASHRAE amendment 

demonstrates that there is no substantial 

doubt that that the industry test 

procedure does not meet the EPCA 

requirements. Id. DOE will make this 

determination only after seeking data 

and information from interested parties 

and the public to help inform DOE’s 

views. DOE will seek from interested 

stakeholders and the public data and 

information to assist in making this 

determination, prior to publishing a 

proposed rule to adopt a different test 

procedure. Id. 

II. Synopsis of the Notice of Proposed 

Rulemaking 

In this NOPR, DOE is proposing to 

establish a definition for DX–DOAS as 

a category of commercial package air 

conditioning and heating equipment 

and adopt a new test procedure for a 

subset of DX–DOASes (i.e., DDX– 

DOASes), consistent with the industry 

consensus test standard as specified in 

ASHRAE Standard 90.1–2019. The 

proposed test procedure applies to all 

DDX–DOASes for which ASHRAE 90.1– 

2019 specifies standards, with the 

exception of ground-water-source DDX– 

DOASes, as discussed in section III.A.1 

of this NOPR. More specifically, DOE 

proposes to update 10 CFR 431.96, 

‘‘Uniform test method for the 

measurement of energy efficiency of 

commercial air conditioners and heat 

pumps,’’ to adopt a new test procedure 

for DDX–DOASes as follows: (1) 

Incorporate by reference AHRI Standard 

920–2020 (I–P), ‘‘Performance Rating of 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36022 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

7 ‘‘Test operating tolerance’’ refers to the 

maximum permissible range that a measurement 

may vary over a specified test interval. ‘‘Test 

condition tolerance’’ refers to the maximum 

permissible difference between the average value of 

the measured test parameter and the specified test 

condition. 

Direct Expansion-Dedicated Outdoor 

Air System Units’’ (AHRI 920–2020), the 

most recent version of the test 

procedure recognized by ASHRAE 

Standard 90.1 for DDX–DOASes, and 

the relevant industry standards 

referenced therein; (2) establish the 

scope of coverage for the DDX–DOAS 

test procedure; (3) add definitions for 

DX–DOASes and DDX–DOASes, as well 

as additional terminology required by 

the test procedure; (4) adopt the 

integrated seasonal moisture removal 

efficiency, as measured according to the 

most recent applicable industry 

standard (ISMRE2), and integrated 

seasonal coefficient of performance 

(ISCOP2), as measured according to the 

most recent applicable industry 

standard, as energy efficiency 

descriptors for dehumidification and 

heating mode, respectively; and (5) 

establish representation requirements. 

DOE proposes to add a new Appendix 

B to Subpart F of Part 431, titled 

‘‘Uniform test method for measuring the 

energy consumption of dehumidifying 

direct expansion-dedicated outdoor air 

systems,’’ (Appendix B) that would 

include the new test procedure 

requirements for DDX–DOASes. In 

conjunction, DOE proposes to amend 

Table 1 in 10 CFR 431.96 to identify the 

newly added Appendix B as the 

applicable test procedure for testing 

DDX–DOASes. DOE has tentatively 

determined that the proposed test 

procedure would not be unduly 

burdensome to conduct. 

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 PROPOSED TEST PROCEDURE FOR DDX–DOASES

Proposed test procedure Attribution 

Incorporates by reference AHRI 920–2020 and other relevant industry test standards referenced by that 

standard. AHRI 920–2020 includes: 

Adopt industry test procedure. 

—test methods for DDX–DOAS with and without ventilation energy recovery systems (VERS); 

—test operating conditions, including Standard Rating Conditions, simulated ventilation air conditions 

for optional test methods for DDX–DOASes with VERS, supply air target conditions, supply and return airflow rates, and external static pressure; 

—testing instrumentation and apparatus instructions; 

—test operating and condition tolerances 7; 

—a list of components that must be present for testing; and 

—provisions for testing units with certain optional features. 

Defines DX–DOASes as covered equipment which meet the EPCA definition for small, large, or very-large 

commercial package air conditioning and heating equipment.

Establish equipment coverage. 

Defines the scope of coverage of the test procedure, including defining DDX–DOASes to distinguish them 

from other kinds of equipment and a capacity limit based on moisture removal capacity (MRC).

Clarify scope of test procedure. 

Adopts ISMRE2 and ISCOP2 as the seasonal efficiency descriptors for dehumidification and heating mode, 

respectively, as specified in AHRI 920–2020.

Adopt industry test procedure. 

Provides minor corrections and additional instruction consistent with AHRI 920–2020 by: 

—specifying the external head pressure requirements for DDX–DOASes with integral water pumps; 

Clarify instructions in the industry 

test procedure. 

—specifying general control setting requirements; 

—correcting a typographical error in the calculation of the degradation coefficient; and 

—providing a missing definition necessary for the interpretation of the airflow setting instructions. 

Specifies representation requirements, including a basic model definition, sampling plan requirements, and 

use of alternative energy-efficiency determination methods (AEDMs).

Provide for representations of energy efficiency consistent with 

other commercial air conditioner/ 

heat pump equipment. 

III. Discussion 

The following sections discuss DOE’s 

proposal to define DX–DOASes as a 

category of small, large and extra-large 

commercial package air conditioning 

and heating equipment and to adopt a 

new test procedure for DDX–DOASes, a 

subset of DX–DOASes, and address 

relevant comments received in response 

to specific issues DOE raised in the July 

2017 ASHRAE TP RFI. Commenters’ 

references to ‘‘DX–DOASes’’ or 

‘‘DOASes’’ have been changed to ‘‘DDX– 

DOASes’’ where DOE understands the 

commenters to be specifically 

discussing DX–DOASes that would 

meet the dehumidification performance 

criterion as proposed. 

A. Scope of Applicability 

1. Equipment Coverage 

As discussed, DOE has initially 

determined that DX–DOASes are a 

category of small, large, and very large 

commercial package air conditioning 

and heating equipment and, therefore, 

are covered equipment under EPCA. (42 

U.S.C. 6311(1)(B)–(D)) DX–DOASes 

operate similarly to more typical 

commercial package air conditioning 

equipment in that they provide 

conditioning of outdoor ventilation air 

using a refrigeration cycle consisting of 

a compressor, condenser, expansion 

valve, and evaporator. However, DX– 

DOASes are designed to provide 

ventilation and conditioning of 100- 

percent outdoor air, while outdoor air 

makes up only a small portion of the 

total airflow for typical commercial 

package air conditioning and heating 

equipment (e.g., usually less than 50 

percent). 

As discussed further in section III.A.4 

of this document, industry provides 

several definitions for DX–DOASes, but 

DOE notes that the industry definitions 

for ‘‘DX–DOAS’’ specifically refer to the 

DDX–DOASes that are covered by the 

scope of those industry test standards, 

which does not include nondehumidifying (i.e., sensible-only) DX– 

DOASes that exist on the market. 

In this NOPR, DOE is proposing to 

define ‘‘direct expansion-dedicated 

outdoor air system, or DX–DOAS,’’ as a 

category of small, large, or very large 

commercial package air conditioning 

and heating equipment which is capable 

of providing ventilation and 

conditioning of 100-percent outdoor air 

or marketed in materials (including but 

not limited to, specification sheets, 

insert sheets, and online materials) as 

having such capability. This proposed 

definition is based, in part, on the 

definition in section 3.6 of AHRI 920– 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36023 

8 ‘‘Sensible cooling’’ refers to the process of 

cooling air by reducing its dry bulb temperature 

without changing its moisture content. 9A notation in the form ‘‘AHRI, No. 11 at pp. 10– 

11’’ identifies a written comment: (1) Made by 

AHRI; (2) recorded in document number 11 that is 

filed in the docket of this test procedure rulemaking 

(Docket No. EERE–2017–BT–TP–0018) and 

available for review at www.regulations.gov; and (3) 

which appears on pages 10 through 11 of document 

number 11. 

10AHRI 920–2020 acknowledges the influence of 

barometric pressure on humidity ratio for the inlet 

air conditions specified in terms of dry bulb and 

wet bulb temperature, allowing an upward 

adjustment of the maximum supply air dew point 

temperature that must be achieved, such that the 

moisture removal rate matches that which would 

occur at standard barometric pressure when 

supplying 55 °F dew-point supply air—this 

maximum supply air dew point increases linearly 

as barometric pressure decreases, up to 57.3 °F at 

the minimum-allowed 13.7 psia test pressure. 

2020, as discussed in section III.A.4 of 

this document. 

The proposed definition of DX–DOAS 

would include all air-cooled, air-source 

heat pump, and water-cooled equipment 

subcategories specified in ASHRAE 

Standard 90.1. For water-source heat 

pump equipment, ASHRAE Standard 

90.1 includes three configurations— 

ground-source, closed loop; groundwater-source; and water-source. The 

EPCA definition for ‘‘commercial 

package air conditioning and heating 

equipment’’ specifically excludes 

ground-water-source equipment (42 

U.S.C. 6311(8)(A)), so in proposing to 

define (at 10 CFR 431.92) DX–DOAS as 

a category of small, large, or very large 

commercial package air conditioning 

and heating equipment, ground-watersource DX–DOASes would be excluded 

from coverage under EPCA. 

Issue–1: DOE requests comment on 

the proposed definition for ‘‘direct 

expansion-dedicated outdoor air 

system.’’ DOE also requests comment on 

any additional characteristics not yet 

considered that could help to 

distinguish DX–DOASes from other 

commercial package air conditioning 

and heating equipment. 

2. Scope of Test Procedure 

DOE is proposing to establish a test 

procedure for a subset of DX–DOASes 

(i.e., DDX–DOASes). When operating in 

humid conditions, the dehumidification 

load is a much larger percentage of the 

total cooling load for a DDX–DOAS than 

for a typical commercial package air 

conditioning system. DDX–DOASes in 

particular handle a significantly higher 

amount of total cooling (both sensible 

and latent) per pound of air at design 

conditions (i.e., the warmest or most 

humid expected summer conditions), 

and a DDX–DOAS is designed to 

accommodate greater variation in 

entering air temperature and humidity, 

because outdoor conditions can vary 

much more than typical indoor 

conditions. As discussed, not all DX– 

DOASes are designed to dehumidify 

outdoor air at the most humid expected 

summer conditions to a level consistent 

with comfortable indoor conditions, 

such as a dew point temperature less 

than 55 °F (e.g., sensible-only cooling 8

DX–DOASes). AHRI stated that sensibleonly 100-percent outdoor air units 

should not be covered by ANSI/AHRI 

920–2015 because they are not intended 

to dehumidify the ventilation air. 

(AHRI, No. 11 at pp. 10–11) 9

Because DOE is aware of sensibleonly DX–DOASes, DOE aims to further 

delineate those DX–DOASes that would 

be subject to the proposed test 

procedure (i.e., DDX–DOASes). Section 

2.2 of AHRI 920–2020 explicitly 

excludes ‘‘Sensible-only 100% Outdoor 

Air Units’’ from the scope of its test 

standard. Accordingly, DOE proposes to 

define DDX–DOASes (the subject of this 

proposed test procedure) in 10 CFR 

431.92 as those DX–DOASes specifically 

having the capability to dehumidify air 

to a dew point of 55 °F when operating 

under Standard Rating Condition A as 

specified in Table 4 or Table 5 of AHRI 

920–2020 with a barometric pressure of 

29.92 in Hg. The 55 °F dew point is 

specified in ANSI/AHRI 920–2015 and 

AHRI 920–2020 as the maximum dew 

point temperature for the supply air for 

the dehumidification mode tests.10 This 

maximum dew point temperature 

requirement for DDX–DOASes provides 

a key differentiator from other DX– 

DOASes, which typically cannot 

dehumidify 100-percent outdoor air to a 

dew point this low. This element is 

consistent with the definition in AHRI 

920–2020. 

AHRI 920–2020 does not specify at 

what airflow the dehumidification 

element is to be evaluated. DOE 

proposes to include within the proposed 

definition of DDX–DOAS that the DDX– 

DOAS be capable of providing the 

specified dehumidification capability 

for any portion of the range of air flow 

rates advertised in manufacturer 

materials. This provision would provide 

additional specificity to the definition 

found in AHRI 920–2020 to account for 

manufacturers that may specify a range 

of airflows for a given model. 

As proposed, the test procedure 

would apply to DDX–DOASes within 

the capacity limits as discussed in the 

following section. 

Issue–1: DOE requests comment on 

the proposed definition for 

‘‘dehumidifying direct expansiondedicated outdoor air system.’’ 

Specifically, DOE requests comment on 

the proposed criteria for distinguishing 

a ‘‘dehumidifying direct expansiondedicated outdoor air system’’ from a 

‘‘direct expansion-dedicated outdoor air 

system’’ more generally. DOE also 

requests comment on any additional 

characteristics not yet considered that 

could help to distinguish DDX–DOASes 

from DX–DOASes more generally. 

3. Capacity Limit 

As stated, EPCA defines as covered 

equipment small, large, and very large 

commercial package air conditioning 

and heating equipment. (42 U.S.C. 

6311(1)(B)–(D)) EPCA defines ‘‘small 

commercial package air conditioning 

and heating equipment’’ as commercial 

package air conditioning and heating 

equipment that is rated below 135,000 

Btu per hour (cooling capacity). (42 

U.S.C. 6311(8)(B)) The term ‘‘large 

commercial package air conditioning 

and heating equipment’’ means 

commercial package air conditioning 

and heating equipment that is rated—(i) 

at or above 135,000 Btu per hour; and 

(ii) below 240,000 Btu per hour (cooling 

capacity). (42 U.S.C. 6311(8)(C)) The 

term ‘‘very large commercial package air 

conditioning and heating equipment’’ 

means commercial package air 

conditioning and heating equipment 

that is rated—(i) at or above 240,000 Btu 

per hour; and (ii) below 760,000 Btu per 

hour (cooling capacity). (42 U.S.C. 

6311(8)(D)) 

In response to the July 2017 ASHRAE 

TP RFI, AHRI commented that DOE’s 

regulations for DDX–DOASes should be 

capped at a reasonable capacity, similar 

to the 760,000 Btu/h limit for 

commercial packaged air conditioning 

equipment. AHRI stated that laboratory 

limitations may limit testing using 

ANSI/AHRI 920–2015 to 300 lbs. of 

moisture per hour at Standard Rating 

Condition A and to units not physically 

larger than more typical commercial 

package air conditioning and heating 

equipment with a capacity of 760,000 

Btu/h. The commenter also stated that 

the market for these larger, typical 

commercial package air conditioning 

equipment and DDX–DOAS units (with 

a capacity greater than 760,000 Btu/h, or 

equivalent) is very small and 

customized. AHRI stated that the 

customization helps customers 

minimize energy consumption for their 

application. (AHRI, No. 11 at p. 20) 

As discussed, DOE has tentatively 

concluded that DX–DOASes meet the 

EPCA definition for ‘‘commercial 

package air conditioning and heating 

equipment,’’ and, thus, are to be 

considered as a category of that covered 

equipment. (42 U.S.C. 6311(8)(A)) The 

upper capacity limit of commercial 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36024 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

11 ‘‘Supply air’’ for a DDX–DOAS refers to 

conditioned air that is supplied to the conditioned 

space. 

package air conditioning subject to the 

DOE test procedures is 760,000 Btu per 

hour, based on the definition of ‘‘very 

large commercial package air 

conditioning and heating equipment.’’ 

(42 U.S.C. 6311(8)(D)) 

For DDX–DOASes specifically, AHRI 

920–2020 does not provide a method for 

determining capacity in terms of Btu per 

hour, but instead, it specifies a 

determination of capacity in terms of 

moisture removal capacity (MRC). DOE 

proposes to translate the upper capacity 

for coverage of commercial package air 

conditioning and heating units 

established in EPCA (i.e., 760,000 Btu 

per hour) from Btu per hour to MRC for 

DDX–DOASes. Specifically, DOE is 

proposing, consistent with section 6 of 

AHRI 920–2020, to translate the upper 

limit from Btu per hour to MRC of the 

DDX–DOAS when delivering 

dehumidified supply air at a 55 °F dew 

point. Manufacturers would use their 

tested value of MRC to determine if a 

DDX–DOAS is subject to the test 

procedure. 

To translate Btu per hour to MRC, 

DOE calculated the maximum airflow 

that could be supplied at a 55 °F 

dewpoint for Standard Rating Condition 

A as specified in Table 4 and Table 5 

of AHRI 920–2020 by cooling and 

dehumidifying it with an evaporator 

with a refrigeration capacity of 760,000 

Btu per hour. DOE calculated this based 

on air entering the evaporator at 

Standard Rating Condition A (95 °F drybulb temperature and 78 °F wet-bulb 

temperature) and air exiting the 

evaporator at 55 °F dew point and 95- 

percent relative humidity at a standard 

barometric pressure of 29.92 in Hg. DOE 

then calculated the MRC that 

corresponds to those conditions. Based 

on these calculations, DOE is proposing 

to limit the scope of this proposed test 

procedure to DDX–DOAS units with a 

MRC less than 324 lbs. per hour based 

on Standard Rating Condition A as 

specified in Table 4 or Table 5 of AHRI 

920–2020. 

Issue–2: DOE seeks comment on its 

translation of Btu per hour to MRC and 

specifically its proposal to translate the 

upper capacity limit for DDX–DOASes 

such that a model would be considered 

in scope if it has an MRC less than 324 

lbs. per hour. 

4. Industry Terminology 

As stated, DOE is proposing 

definitions for DX–DOAS and DDX– 

DOAS following a review of industry 

standards and consistent with the 

applicability of the relevant industry 

testing standard. Both ANSI/AHRI 920– 

2015 and ANSI/ASHRAE 198–2013 

include definitions for ‘‘DX-Dedicated 

Outdoor Air System Units.’’ Section 3.3 

of ANSI/AHRI 920–2015 defines ‘‘DXDedicated Outdoor Air System Units’’ as 

a type of air-cooled, water-cooled, or 

water-source factory assembled product 

which dehumidifies 100-percent 

outdoor air to a low dew point, and 

includes reheat that is capable of 

controlling the supply dry-bulb 

temperature of the dehumidified air to 

the designed supply air 11 temperature. 

This conditioned outdoor air is then 

delivered directly or indirectly to the 

conditioned space(s). It may precondition outdoor air by containing an 

enthalpy wheel, sensible wheel, 

desiccant wheel, plate heat exchanger, 

heat pipes, or other heat or mass transfer 

apparatus. This is the same definition 

used in ASHRAE Standard 90.1–2019. 

Section 3 of ANSI/ASHRAE 198–2013 

defines a ‘‘DX Dedicated Outdoor Air 

Systems Unit (DX–DOAS)’’ as a type of 

air-cooled, water-cooled, or watersource factory-assembled product that is 

capable of dehumidifying 100-percent 

outdoor air to a low dew point and may 

be capable of controlling the dry-bulb 

temperature of the dehumidified air to 

the designed supply air temperature. 

This conditioned outdoor air may be 

delivered directly or indirectly to the 

conditioned space(s). It may precondition outdoor air prior to direct 

expansion cooling by incorporating an 

enthalpy wheel, sensible wheel, 

desiccant wheel, plate heat exchanger, 

heat pipes, or other heat or mass transfer 

apparatus. The product may also 

include a supplementary heating system 

for use when outdoor air requires 

heating beyond the capability of the 

refrigeration system and/or other heat 

transfer apparatus. 

As part of the July 2017 ASHRAE TP 

RFI, DOE requested comment on certain 

aspects of these two industry definitions 

of dedicated outdoor air systems. 82 FR 

34427, 34435–34436 (July 25, 2017). On 

February 4, 2020, AHRI published AHRI 

920–2020, which made changes to the 

definition of ‘‘Dedicated Outdoor Air 

System Unit’’ as compared to the 

definition in ANSI/AHRI 920–2015 (and 

ASHRAE Standard 90.1–2019). Section 

3.6 of AHRI 920–2020 defines 

‘‘Dedicated Outdoor Air System Unit’’ 

as a type of air-cooled, evaporativelycooled, or water-cooled air-conditioner, 

or an air-source or water source heat 

pump, that is a factory assembled 

product designed and marketed and 

sold to provide ventilation and 

dehumidification of 100% outdoor air, 

is capable of dehumidifying air to a 

55 °F dew point when operating under 

Standard Rating Condition A as 

specified in Table 4 or Table 5 of this 

test standard with a barometric pressure 

of 29.92 in Hg, and may include reheat. 

It may include pre-conditioning of 

outdoor air using an enthalpy wheel, 

sensible wheel, desiccant wheel, plate 

heat exchanger, heat pipes, or other heat 

or mass transfer apparatus. Heating 

components are optional and may 

include electrical resistance, steam, hot 

water, or gas heat. In addition, it may 

provide for air cleaning or may include 

mixing box or economizer dampers to 

allow return air to be intermittently 

used as allowed by the controls. 

Both ANSI/AHRI 920–2015 and 

ANSI/ASHRAE 198–2013 address 

equipment that dehumidifies (or is 

capable of dehumidifying) 100-percent 

outdoor air to a low dew point. As 

discussed, in its review of available 

equipment, DOE found units marketed 

as ‘‘dedicated outdoor air systems,’’ and 

other units marketed for ‘‘100-percent 

outdoor air’’ applications, both of which 

can also operate with less than 100- 

percent outdoor air. Such units have a 

return air damper that allows 

modulating the amount of return air that 

is recirculated from the conditioned 

space and mixed with the incoming 

outdoor air before the mixed air is 

conditioned. More typical commercial 

package air conditioning equipment also 

often incorporates a similar damper to 

mix return air and outdoor air. 

Additionally, like the industry 

definitions for dedicated outdoor air 

systems, which DOE notes would be 

DDX–DOASes as that term is proposed 

to be defined, some categories of 

commercial package air conditioning 

equipment can dehumidify 100-percent 

outdoor air, although typically not to a 

dew point as low as the industry 

specification for DDX–DOASes. 

As part of the July 2017 ASHRAE TP 

RFI, DOE requested information on the 

range of the maximum percentage of 

return air intake relative to total airflow 

of models of equipment that DOE 

generally referred to as ‘‘DOASes’’ in 

order to determine whether the 

maximum return air percentage is an 

important distinguishing feature of 

DDX–DOASes. DOE also requested 

information on the difference in 

dehumidification capabilities of more 

typical commercial package air 

conditioning equipment and equipment 

that DOE referred to as DOASes when 

operating with 100-percent outdoor air. 

82 FR 34427, 34435 (July 25, 2017). 

Ingersoll Rand and Carrier 

commented that there are not one or two 

features or criteria that definitively 

distinguish DDX–DOASes from more 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36025 

12ANSI/AHRI Standard 340/360, ‘‘Performance 

Rating of Commercial and Industrial Unitary Airconditioning and Heat Pump Equipment’’ 

(Available at: www.ahrinet.org/) (Last accessed 

April 19, 2021). 

13As discussed, the term DX–DOAS as defined by 

ASHRAE 90.1–2019 is equivalent to the term DDX– 

DOAS as defined by DOE in this NOPR. 

typical commercial package air 

conditioning equipment. (Ingersoll 

Rand, No. 12 at p. 2; Carrier, No. 6 at 

p. 2) AHRI and Carrier commented that 

there may be several potential 

applications for DDX–DOASes, some of 

which may not be 100-percent outdoor 

air. (AHRI, No. 11 at p. 9; Carrier, No. 

6 at p. 2) AHRI and Ingersoll Rand 

stated, for example, that DDX–DOASes 

may be supplied with recirculation 

dampers that allow them to efficiently 

dehumidify recirculated air when the 

building is unoccupied. AHRI stated 

that, as a result, it is not possible to 

select a specific crossover percentage of 

return air intake relative to total airflow 

that would differentiate DDX–DOASes 

from more typical commercial package 

air conditioning equipment. (AHRI, No. 

11 at p. 9; Ingersoll Rand, No. 12 at p. 

2) Goodman supported AHRI’s position, 

adding that when the return air intake 

relative to the total airflow is less than 

10–30 percent, ANSI/AHRI 920–2015 is 

more appropriate than ANSI/AHRI 340/ 

360 12 in non-western climates. 

(Goodman, No. 14 at p. 2) 

As discussed, not all DX–DOASes are 

designed to provide dehumidification 

(to a low dew point) over larger 

variation in entering air temperature 

and humidity. As such, DOE is 

proposing to define DDX–DOAS to 

distinguish such equipment from DX– 

DOAS more generally, as provided in 

the previous sections. The DDX–DOAS 

definition is consistent with the 

definition in section 3.6 of AHRI 920– 

2020 for the equipment subject to the 

scope of that industry test standard. 

DOE noted in the July 2017 ASHRAE 

TP RFI that one difference between the 

definitions in ANSI/ASHRAE 198–2013 

and ANSI/AHRI 920–2015 (and now 

AHRI 920–2020) is related to reheat. 

ANSI/AHRI 920–2015 specifies that a 

Direct Expansion-Dedicated Outdoor 

Air System Unit includes reheat, which 

is used to raise the temperature of 

cooled and dehumidified air to a design 

supply air temperature. The ANSI/ 

ASHRAE 198–2013 definition provides 

that a DX Dedicated Outdoor Air 

Systems Unit, as defined by that 

industry standard, may have reheat but 

does not require reheat. DOE requested 

comment on whether and how reheating 

functionality should be included in the 

DDX–DOAS definition. 82 FR 34427, 

34435–34436 (July 25, 2017). 

In response to the July 2017 ASHRAE 

TP RFI, AHRI and Greenheck 

commented that while capturing reheat 

performance in the test procedure for 

DDX–DOAS equipment is an important 

aspect to many installations, some 

building HVAC designs incorporating 

DDX–DOAS equipment operate without 

any reheat capabilities. AHRI and 

Greenheck suggested that the definition 

of DDX–DOAS should not require 

reheat, as it is important for owners and 

designers to be able to select 100- 

percent outdoor air units with varying 

amounts of reheat or no reheat. (AHRI, 

No. 11 at pp. 10–11, 20–21; Greenheck, 

No. 13 at p. 2) AHRI further commented 

that DDX–DOAS design and optimum 

efficiency varies with climate and 

application, and that the design is often 

customized to accommodate the 

different needs of different applications. 

AHRI asserted that regulations must 

allow for these differences to avoid 

increasing energy consumption for a 

given project. (AHRI, No. 11 at p. 20– 

21) Greenheck commented that the 

supplementary heat penalty included in 

ANSI/AHRI 920–2015 unfairly 

penalizes units without reheat, and 

Greenheck suggested two options for 

rating units without reheat. (Greenheck, 

No. 13 at pp. 2–3). Carrier also 

commented that reheat functionality is 

an application issue and is not 

applicable to the definition in a test 

standard. (Carrier, No. 6 at p. 3) 

DOE recognizes that the optimumefficiency DDX–DOAS design varies 

with climate and application. DOE also 

understands that the supplementary 

heat penalty in ANSI/AHRI 920–2015 is 

not representative of the way that units 

without reheat are used in the field. As 

is discussed in section III.B.2.a of this 

document, as part of AHRI 920–2020, 

AHRI modified the ISMRE metric to 

remove the supplementary heat penalty 

in recognition that some installation 

conditions may not require reheating. 

As is discussed in section III.B.1 of this 

document, this metric was re-designated 

in AHRI 920–2020 as ISMRE2. AHRI 

920–2020 also includes a separate 

application rating metric, ISMRE270, to 

account for installations where 

reheating is required. Moreover, the 

updated definition in AHRI 920–2020 

recognizes that there are units without 

reheat. As such, DOE is not proposing 

to include a reheat requirement in the 

DX–DOAS or DDX–DOAS definition, 

consistent with AHRI 920–2020. 

Because of the difference in 

terminology between the proposed DOE 

test procedure and the relevant industry 

standards, DOE proposes to include a 

section 2.3(a) in its proposed Appendix 

B indicating that the different 

synonymous terms all refer to 

dehumidifying direct expansiondedicated outdoor air system as defined 

in 10 CFR 431.92. 

Issue–3: DOE requests comment on its 

proposal to clarify what terms are 

synonymous with DDX–DOAS. 

B. Test Procedure for Dehumidifying 

Dedicated Outdoor Air Systems 

Pursuant to EPCA, in response to the 

DDX–DOAS-related updates to ASHRAE 

90.1–2016 (maintained in ASHRAE 

90.1–2019) and updates to the industry 

test standard referenced in ASHRAE 

90.1, DOE proposes to adopt a test 

procedure for DDX–DOASes that 

incorporates by reference the latest 

applicable industry consensus test 

standards. 

In the following sections, DOE 

presents analysis and discussion of 

several test procedure issues and 

proposes a test procedure for DDX– 

DOASes. As discussed in more detail in 

the following sections, DOE has initially 

determined that the proposed test 

procedure for DDX–DOASes would be 

representative of an average use cycle 

and not be unduly burdensome to 

conduct. 

DOE is adopting the generally 

accepted industry testing procedures for 

DDX–DOASes developed by AHRI (i.e., 

AHRI 920–2020) and referenced by 

ASHRAE Standard 90.1, with the 

following modifications as discussed in 

this NOPR: 

D Using the nomenclature DDX– 

DOAS, rather than DX–DOAS, to define 

the equipment subject to the test 

procedure; 

D Defining an upper limit of capacity 

consistent with EPCA’s definition of 

very large commercial package air 

conditioning and heating equipment; 

D Defining ‘‘non-standard low-static 

fan motor,’’ in order to determine the 

appropriate airflow setting procedure; 

D Specifying the external head 

pressure requirements for testing DDX– 

DOASes with integral water pumps; 

D Requiring that control settings 

remain unchanged for all Standard 

Rating Conditions once system set-up 

has been completed prior to testing; 

D Specifying requirements for testing 

equipment available with multiple 

refrigerant options; and 

D Correcting a typographical error 

within one of the equations. 

1. Industry Consensus Test Standards 

As first established in ASHRAE 90.1– 

2016, ASHRAE Standard 90.1–2019 

specifies separate equipment classes for 

DDX–DOASes 13 and sets minimum 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36026 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

14As discussed in section III.A.1 of this NOPR, 

the EPCA definition for ‘‘commercial package air 

conditioning and heating equipment’’ specifically 

excludes ground-water-source equipment (42 U.S.C. 

6311(8)(A)). Accordingly, DOE is proposing to 

exclude this equipment from the scope of 

applicability of the test procedure. 

15Standard Rating Conditions in the AHRI 920 

test procedure represent full-load and part-load 

operating conditions for testing DX–DOASes. 

Standard Rating Condition A represents full-load 

operation in dehumidification mode, whereas 

Standard Rating Conditions B–D represent part-load 

operation in dehumidification mode. Standard 

Rating Condition F represents full-load operation in 

heat pump mode at low temperatures, and Standard 

Rating Condition E represents full-load operation in 

heat pump mode at high temperatures. 

16As discussed in section III.B.3.a of this NOPR, 

AHRI 920–2020 additionally provides a method for 

calculating ISMRE270, an application metric for the 

dehumidification efficiency with the inclusion of 

the supplementary heat penalty. The subscript ‘‘70’’ 

indicates the inclusion of energy use from any 

supplementary heat that is required to raise the 

supply air dry bulb temperature to 70 °F. 

17 Dew point is the temperature below which 

water begins to condense from the water vapor state 

in humid air into liquid water droplets. Dew point 

varies with humidity (e.g., a low dew point 

indicates low humidity and vice versa) and is, 

therefore, used to specify the humidity of the 

supply air. 

efficiency levels using the integrated 

seasonal moisture removal efficiency 

(ISMRE) metric for all DDX–DOAS 

classes and also the integrated seasonal 

coefficient of performance (ISCOP) 

metric for air-source heat pump and 

water-source heat pump DDX–DOAS 

classes. ASHRAE Standard 90.1–2019 

specifies that both metrics are to be 

measured in accordance with ANSI/ 

AHRI Standard 920–2015, ‘‘Performance 

Rating of DX-Dedicated Outdoor Air 

System Units’’ (ANSI/AHRI 920–2015). 

ANSI/AHRI 920–2015 specifies the 

method for testing DDX–DOASes, in 

part, through a reference to ANSI/ 

ASHRAE Standard 198–2013, ‘‘Method 

of Test for Rating DX-Dedicated Outdoor 

Air Systems for Moisture Removal 

Capacity and Moisture Removal 

Efficiency’’ (ANSI/ASHRAE 198–2013). 

ANSI/AHRI 920–2015 specifies 

Standard Rating Conditions (i.e., 

instructions on setting air and liquid 

flow rates, and equations for calculating 

ISMRE and ISCOP). Table 2 and Table 

3 of ANSI/AHRI 920–2015 provide 

outdoor and return air conditions for 

four Standard Rating Conditions for the 

dehumidification test and two Standard 

Rating Conditions for the heating test for 

heat pump DDX–DOASes. These tables 

also provide condenser cooling water 

temperatures (for both cooling tower 

and chilled water condensers) for watercooled (cooling-only) DDX–DOASes and 

water temperatures for water-source, 

ground-source closed-loop, and groundwater source 14 heat pump DDX– 

DOASes. 

ANSI/ASHRAE 198–2013 includes 

requirements on instrumentation, test 

set-up, tolerances, method of test, and 

calculations for moisture removal 

capacity (MRC), moisture removal 

efficiency (MRE), heating capacity (qhp) 

and heating coefficient of performance 

(COP). The MRE for the 

dehumidification test is calculated for 

Standard Rating Conditions 15 A, B, C, 

and D of Table 2 or Table 3 of ANSI/ 

AHRI 920–2015 for air-cooled, watercooled, and water-source heat pump 

DDX–DOASes. Similarly, COP is 

calculated for the heating mode test for 

Standard Rating Conditions E and F of 

Table 2 or Table 3 of ANSI/AHRI 920– 

2015 for heat pump DDX–DOASes. The 

MRE and COP values are subsequently 

used to calculate ISMRE and ISCOP 

using weights that correspond to 

temperature bin data for representative 

cities in the United States. 

DOE notes that AHRI recently revised 

AHRI 920 and published an updated 

version on February 4, 2020, AHRI 

Standard 920–2020 (I–P), ‘‘Performance 

Rating of Direct Expansion Dedicated 

Outdoor Air System Units’’ (AHRI 920– 

2020). AHRI 920–2020, which continues 

to reference ANSI/ASHRAE 198–2013, 

includes revisions that DOE has initially 

determined improve the 

representativeness, repeatability, and 

reproducibility of the test methods 

while also reducing test burden. These 

revisions include, among other things, 

the following: (1) Expanded scope of 

coverage of the test procedure by no 

longer imposing an upper limit of 97 

lbs/hr on DDX–DOAS MRC, thereby 

making the test procedure applicable to 

all DDX–DOASes subject to standards 

under ASHRAE Standard 90.1; (2) 

revised outdoor air dry-bulb 

temperature conditions, external static 

pressures, humidity conditions, and 

weighting factors for ISMRE and ISCOP, 

which were redesignated as ISMRE2 

and ISCOP2, respectively; (3) revised 

calculations for achieving the target 

supply air conditions for units with 

staged capacity control; (4) added a 

supplementary cooling penalty when 

the supply air dry-bulb temperature is 

greater than 75 °F in dehumidification 

mode; (5) removed a supplementary 

heat penalty for the efficiency metric 

ISMRE2 when the supply air dry-bulb 

temperature is less than 70 °F in 

dehumidification mode; 16 (6) revised 

condenser water conditions for watercooled and water-source heat pump 

DDX–DOASes; (7) added requirements 

for supply air dew point temperature; 17

(8) added requirements for outdoor coil 

liquid flow rate; (9) provided additional 

test unit, test facility, instrumentation, 

and apparatus set-up provisions; (10) 

revised test methods for DDX–DOASes 

equipped with VERS; (11) added 

requirements for relief-air-cooled DDX– 

DOASes and DDX–DOASes equipped 

with desiccant wheels; and (12) 

included requirements for secondary 

capacity tests. 

DOE carefully reviewed both ANSI/ 

AHRI 920–2015 and ANSI/ASHRAE 

198–2013, as well as the latest changes 

in AHRI 920–2020, in consideration of 

this NOPR. In the following sections, 

DOE discusses the proposed definition 

for DDX–DOASes, scope of the test 

procedure, efficiency metrics, test 

methods (including the updates to AHRI 

920 in the 2020 version listed in the 

prior paragraph), and sampling 

requirements. Generally, DOE 

incorporates industry standards into the 

regulations by reference to the standard. 

In this NOPR, DOE has proposed to 

incorporate by reference AHRI 920– 

2020. 

DOE is also proposing to incorporate 

by reference several industry standards 

that are referenced by AHRI 920–2020, 

as shown in Table III–1. 

TABLE III–1—ADDITIONAL INDUSTRY

STANDARDS PROPOSED TO BE INCORPORATED BY REFERENCE

Industry standard 

Section(s) in 

AHRI 920–2020 

that reference this 

industry standard 

ANSI/ASHRAE 198– 

2013.

Section 5; Section 6; 

Appendix C. 

ANSI/ASHRAE 37– 

2009.

Section 5; Section 6; 

Appendix C. 

ANSI/ASHRAE 1060– 

2018.

Section C4. 

ANSI/ASHRAE 41.1– 

2013.

Section C3.3.1. 

ANSI/ASHRAE 41.6– 

2014.

Section C3.1.3.2. 

In response to the July 2017 ASHRAE 

TP RFI, AHRI commented that the 

ISMRE and ISCOP levels specified for 

DDX–DOASes in ASHRAE 90.1–2016 

will need adjustment if changes to the 

test procedure negatively impact these 

values (AHRI, No. 11 at p. 20). 

This NOPR proposes to incorporate by 

reference the latest version of the 

industry test procedure for DDX– 

DOASes which is recognized by 

ASHRAE Standard 90.1: AHRI 920 (the 

latest version being AHRI 920–2020). 

When the test procedures referenced in 

ASHRAE Standard 90.1 are updated, 

EPCA requires DOE to amend the 

Federal test procedures for such covered 

ASHRAE equipment (which 

manufacturers are required to use in 

order to certify compliance with energy 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36027 

18Space-neutral air, or neutral air, refers to air 

leaving an air conditioner being at the target 

conditions for the occupied space in the building 

(without the need for subsequent sensible or latent 

cooling). 

19As discussed in section III.B.1 of this 

document, AHRI 920–2020 include separate 

application metrics (i.e., ISMRE270) to be used for 

additional representations and that are calculated 

with a supplementary heat penalty based on raising 

the supply air dry-bulb temperature up to 70 °F. 

conservation standards mandated under 

EPCA) to be consistent with the 

amended industry consensus test 

procedure. (42 U.S.C. 6314(a)(4)(B)) 

The energy efficiency standards 

specified in ASHRAE Standard 90.1 are 

based on ANSI/AHRI 920–2015 and 

ANSI/ASHRAE 198–2013. However, the 

amendments adopted in AHRI 920–2020 

result in changes to the measured 

efficiency metrics as compared to the 

results under ANSI/AHRI 920–2015. As 

discussed, DOE has not established in 

its regulations energy conservation 

standards specifically for DDX–DOASes. 

DOE will address any potential 

differences in the measured energy 

efficiency under the most recent 

industry test procedure as compared to 

the industry test procedure on which 

the ASHRAE Standard 90.1 levels are 

based at such time as DOE evaluates the 

ASHRAE Standard 90.1 levels for DDX– 

DOASes (i.e., by developing an 

appropriate crosswalk, as necessary). 

Specifically, DOE intends to request that 

DDX–DOAS manufacturers provide any 

data and/or analysis that indicates 

whether and how much the measured 

rating of DDX–DOASes would be 

expected to change under the most 

recent version of the industry consensus 

test standard. 

Issue–4: DOE requests comment and 

data on the development of a crosswalk 

from the efficiency levels in ASHRAE 

Standard 90.1 based on ANSI/AHRI 

920–2015 to efficiency levels based on 

AHRI 920–2020. DOE is specifically 

seeking data on how dehumidification 

and heating efficiency ratings for a given 

DDX–DOAS model are impacted when 

measured using AHRI 920–2020 as 

compared to ANSI/AHRI 920–2015. 

2. Efficiency Metrics 

a. Dehumidification Metric 

ASHRAE 90.1–2016 adopted a 

dehumidification efficiency metric for 

DDX–DOASes. Specifically, ASHRAE 

90.1–2016 uses ISMRE, as presented in 

section 3.10 of ANSI/AHRI 920–2015, as 

a seasonal efficiency metric calculated 

as a weighted average of MRE for four 

different dehumidification rating 

conditions. MRE for each test condition 

is the MRC for that condition divided by 

electric power input, including 

consideration of electric resistance 

reheat if needed to raise supply air 

temperature to 70 °F (i.e., 

‘‘supplementary heat’’). MRC represents 

the rate at which the DDX–DOAS 

removes humidity from the air in 

pounds of moisture per hour. As 

discussed further in section III.B.2.c of 

this document, AHRI indicated that the 

seasonal weighting factors for 

determining ISMRE, as specified in 

ANSI/AHRI 920–2015, were developed 

based on climate data from a sample of 

twelve cities chosen to be representative 

of a wide range of climatic data in the 

United States. 

The primary function of DDX– 

DOASes is to provide conditioned 

(cooled and dehumidified, or heated) 

outdoor air. In the cooling/ 

dehumidifying season, these units 

provide sensible cooling that reduces 

the temperature of the outdoor air in 

addition to dehumidifying. DOE noted 

in the July 2017 ASHRAE TP RFI that 

the ISMRE metric specified in ANSI/ 

AHRI 920–2015 does not include any 

provisions to measure the sensible 

cooling contribution provided by the 

DDX–DOAS. 82 FR 34427, 34436 (July 

25, 2017). For Standard Rating 

Conditions A and B in Table 2 and 

Table 3 of ANSI/AHRI 920–2015, 

conditioning the air to a space 

temperature (70 °F) requires sensible 

cooling as well as latent cooling. In the 

July 2017 ASHRAE TP RFI, DOE 

requested comment on whether the 

DDX–DOAS efficiency metric should 

account for this sensible cooling. 82 FR 

34427, 34436 (July 25, 2017). 

In response to the July 2017 ASHRAE 

TP RFI, AHRI commented that DDX– 

DOASes operate with a separate, 

sensible-cooling-only interior cooling 

system, and that adding sensible cooling 

to the metric for DDX–DOAS would 

skew efficiency values toward the nonprimary function of the DDX–DOAS. 

AHRI also stated that the capacity for 

sensible cooling varies between DDX– 

DOAS designs, so the use of spaceneutral air 18 gives a worst-case 

efficiency to be used as comparison. 

(AHRI, No. 11 at p. 12) Carrier 

expressed concern that the current 

metric focuses on latent capacity and 

that a shortcoming of the test procedure 

is that it does not consider sensible 

capacity. Carrier also stated that 

considering only latent capacity would 

be acceptable if the unit delivers spaceneutral air, but some DDX–DOASes can 

provide sensible cooling. (Carrier, No. 6 

at p. 3) 

As discussed in section III.B.2.c of 

this NOPR, DOE proposes to incorporate 

by reference the dehumidification 

metrics contained in the updated 

version of the industry consensus 

standard, AHRI 920–2020. DOE notes 

that the revised dehumidification metric 

in AHRI 920–2020, ISMRE2, does not 

include provisions to determine the 

sensible cooling contribution in the 

metric. However, as discussed in section 

III.B.1 of this document, the ISMRE2 

metric, which is specified in AHRI 920– 

2020 as the required rating metric for 

dehumidification efficiency, removes 

the supplementary heat penalty to avoid 

penalizing DDX–DOAS units that 

provide sensible cooling below 70 °F. 

DOE recognizes that the sensible 

cooling provided by a DDX–DOAS unit 

may be valuable in many applications 

because it reduces the cooling that must 

be provided by interior cooling systems, 

especially at high outdoor temperatures. 

However, for certain applications it may 

be important to reheat the supply air to 

balance the building’s sensible cooling 

load.19 DOE may consider in a future 

rulemaking whether the efficiency 

metric should be revised to include 

sensible cooling, if information is made 

available to support such a change. 

ASHRAE Standard 90.1–2016 uses 

ISMRE (using ANSI/AHRI 920–2015) as 

the metric for the specified minimum 

efficiencies for DDX–DOAS. As 

discussed in section III.B.1 of this 

NOPR, DOE is aware that updates to the 

industry test procedure in AHRI 920– 

2020 using ISMRE2 could impact the 

measured efficiencies of DDX–DOASes 

as compared to ISMRE measured in 

accordance with ANSI/AHRI 920–2015, 

thereby necessitating use of an 

appropriate crosswalk analysis. 

Therefore, DOE will address these 

potential impacts on the measured 

efficiencies in a separate standards 

rulemaking. 

b. Heating Metric 

ASHRAE 90.1–2016 adopted ISCOP, 

as presented in ANSI/AHRI 920–2015, 

as the heating efficiency metric, and it 

also set minimum ISCOP efficiency 

levels for both air-source and watersource heat pump DDX–DOASes. ISCOP 

is a seasonal energy efficiency metric 

and is calculated as the seasonal 

weighted average of heating COPs 

determined for two heating Standard 

Rating Conditions specified in Table 2 

and Table 3 of ANSI/AHRI 920–2015. 

In the July 2017 ASHRAE TP RFI, 

DOE noted that although the 

Department has identified air-source 

heat pump DDX–DOASes available on 

the market, section 3.9 of ANSI/AHRI 

920–2015 defines ISCOP as an energy 

efficiency metric only for water-source 

heat pump DDX–DOASes. 82 FR 34427, 

34436 (July 25, 2017). DOE also noted 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36028 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

20The sample of 12 cities analyzed were: New 

York City, Atlanta, Chicago, El Paso, Houston, 

Kansas City, Miami, Minneapolis, Nashville, New 

Orleans, Norfolk, and Tucson. 

21TMY stands for ‘‘typical meteorological year’’ 

and is a widely used type of data available through 

the National Solar Radiation Database. TMYs 

contain one year of hourly data that best represents 

median weather conditions over a multiyear period. 

The datasets have been updated occasionally, thus 

TMY, TMY2, and TMY3 data are available. See 

nsrdb.nrel.gov/about/tmy.html (last accessed 4/28/ 

21). 

in the July 2017 ASHRAE TP RFI that 

equations in section 10.9 of ANSI/ 

ASHRAE 198–2013 for calculating the 

COP are labeled for application to 

water-source heat pump DDX–DOASes, 

although DOE once again noted that 

they could be applied to air-source heat 

pump DDX–DOASes. Id. As part of the 

July 2017 ASHRAE TP RFI, DOE 

requested comment on the calculation 

procedure for COP for air-source heat 

pumps, including whether the equations 

in ANSI/ASHRAE 198–2013 are 

applicable to air-source heat pumps. Id. 

DOE did not receive any comments on 

this topic. Because ASHRAE Standard 

90.1–2016 specifies minimum efficiency 

levels for both air-source and watersource heat pump DDX–DOASes using 

ANSI/AHRI 920–2015, DOE considers 

the ISCOP and COP calculations to be 

applicable to the minimum efficiency 

levels in ASHRAE Standard 90.1–2016 

for both equipment classes. 

In further clarification, AHRI 920– 

2020 revised the definition of ‘‘Direct 

Expansion-Dedicated Outdoor Air 

System Units’’ and the heating 

efficiency metric (designated as ISCOP2) 

to include both air-source and watersource heat pump DDX–DOASes. The 

ISCOP2 metric specified in section 3.13 

of AHRI 920–2020 also includes 

revisions to the outdoor air conditions, 

weighting factors, and treatment of 

heating capacity calculations. DOE is 

proposing to adopt ISCOP2 as the 

heating efficiency metric for DDX– 

DOASes under the DOE test procedure, 

expressed in Watts (W) of heating 

capacity per W of power input. As 

discussed in section III.B.1 of this 

NOPR, updates to the industry 

consensus test procedure in AHRI 920– 

2020 using ISCOP2 could impact the 

measured heating efficiencies of DDX– 

DOASes as compared to ISCOP 

measured in accordance with ANSI/ 

AHRI 920–2015, thereby necessitating 

use of an appropriate crosswalk 

analysis. Therefore, DOE will address 

these potential impacts on the measured 

heating efficiencies in a separate 

standards rulemaking. 

ISCOP2 is calculated using 

COPISCOP values for Standard Rating 

Conditions E and F that apply a 

supplementary heat penalty to the total 

power input if the supply air dry-bulb 

temperature is less 70 °F. Section 6.11 of 

AHRI 920–2020 includes additional 

application rating heating metrics, 

COPfull and COPDX–DOAS, for additional 

representations. COPDX–DOAS is 

calculated without a supplementary 

heat penalty, while COPfull is used for 

manufacturer-specified outdoor 

conditions. DOE is proposing in section 

2.2.2 of Appendix B to allow COPfull and 

COPDX–DOAS to be used by 

manufacturers for voluntary 

representations. 

c. ISMRE2 and ISCOP2 Weighting 

Factors 

As part of the July 2017 ASHRAE TP 

RFI, DOE requested information about 

analysis of climate data relevant to the 

development of the ISMRE and ISCOP 

test conditions and weighting factors. 82 

FR 34427, 34436 (July 25, 2017). AHRI 

commented that the values and 

weightings for both the 

dehumidification and heating points in 

ANSI/AHRI 920–2015 were developed 

based on climatic data for a sample of 

twelve cities 20 chosen to be 

representative of a wide range of 

climatic conditions in the United States. 

According to AHRI, the climatic bin 

data were based on 24-hour operation 

per day due to the variety of 

applications where DDX–DOASes are 

installed and provide a reasonable 

standard for assessing the part-load 

situations that will be encountered. 

(AHRI, No. 11 at p. 12) DOE notes that 

these test conditions in ANSI/AHRI 

920–2015 were established to represent 

specific regions of the psychrometric 

chart, as shown in the following Table 

III–2 and Table III–3. 

In the development of AHRI 920– 

2020, DOE provided input on weather 

data, and AHRI also reviewed Typical 

Meteorological Year (TMY) 2 21 weather 

data from the National Renewable 

Energy Laboratory. Based, in part, on 

this input and data, AHRI 920–2020 

specifies the ISMRE2 and ISCOP2 test 

conditions and weighting factors, which 

represent the number of hours per year 

for each test condition. Accordingly, 

Table III–2 and Table III–3 also show 

the Standard Rating Conditions and 

weighting factors included in sections 

6.1, 6.12, and 6.13 of AHRI 920–2020. 

DOE is proposing to adopt the weighting 

factors for the ISMRE2 (including the 

test conditions specific for ISMRE270) 

and ISCOP2 metrics, as specified in 

AHRI 920–2020. 

TABLE III–2—ANSI/AHRI 920–2015 AND AHRI 920–2020 DEHUMIDIFICATION MODE STANDARD RATING CONDITIONS AND

ISMRE/ISMRE2/ISMRE270 WEIGHTING FACTORS

Standard 

rating 

condition 

Psychrometric chart region represented 

ANSI/AHRI 920–2015 AHRI 920–2020 

Representative 

condition 

(dry-bulb temperature/ 

wet-bulb temperature) 

ISMRE 

weighting 

factor 

Representative 

condition 

(dry-bulb temperature/ 

wet-bulb temperature) 

ISMRE2 

and 

ISMRE270

weighting 

factor 

A .............. Above 55 °F dew point, Above 75 °F wet-bulb .... 95 °F/78 °F .................... 12 95 °F/78 °F .................... 14 

B .............. Above 55 °F dew point, >69 °F and ≤75 °F wetbulb.80 °F/73 °F .................... 28 80 °F/73 °F .................... 34 

C .............. Above 55 °F dew point, >62 °F and ≤69 °F wetbulb.68 °F/66 °F .................... 36 70 °F/66 °F .................... 39 

D .............. Above 55 °F dew point, >56 °F and ≤62 °F wetbulb.60 °F/58 °F .................... 24 63 °F/59 °F .................... 13 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36029 

TABLE III–3—ANSI/AHRI 920–2015 AND AHRI 920–2020 HEATING MODE STANDARD RATING CONDITIONS AND ISCOP/ 

ISCOP2 WEIGHTING FACTORS

Standard 

rating 

condition 

Psychrometric chart region represented 

ANSI/AHRI 920–2015 AHRI 920–2020 

Representative 

condition 

(dry-bulb temperature/ 

wet-bulb temperature) 

ISCOP 

weighting 

factor 

Representative 

condition 

(dry-bulb temperature/ 

wet-bulb temperature) 

ISCOP2 

weighting 

factor 

E .............. Below 55 °F dew point, >23 °F and ≤64 °F drybulb.35 °F/29 °F .................... 77 47 °F/43 °F .................... 91 

F .............. Below 55 °F dew point, ≤23 °F dry-bulb .............. 16 °F/12 °F .................... 23 17 °F/15 °F .................... 9 

3. Test Method 

This section discusses the various 

issues that DOE identified in the 

industry consensus test standards 

applicable to DDX–DOASes, including 

those raised in the July 2017 ASHRAE 

TP RFI and considered as part of DOE’s 

review of AHRI 920–2020. These issues 

include: (1) Definitions for certain terms 

used in the DDX–DOAS test procedure; 

(2) optional break-in period for DDX– 

DOASes; (3) test facility, 

instrumentation, and apparatus set-up 

issues; (4) DDX–DOAS unit set-up; (5) 

test operating conditions; (6) 

requirements for water-cooled and 

water-source heat pump DDX–DOASes; 

(7) defrost energy use; (8) test methods 

for DDX–DOASes equipped with VERS; 

(9) tolerances; and (10) secondary 

verification tests for dehumidification 

and heating tests. 

Table 1 to 10 CFR 431.96 specifies the 

applicable industry test procedure for 

each category of commercial package air 

conditioning and heating equipment 

and specifies any additional testing 

requirements that may also apply. In 

this NOPR, DOE is proposing to add test 

procedure requirements for DDX– 

DOASes in a separate appendix in 

subpart F to 10 CFR part 431 (i.e., 

proposed Appendix B). Accordingly, 

DOE proposes to include DDX–DOASes 

in Table 1 to 10 CFR 431.96 and to 

reference Appendix B for the DDX– 

DOASes test procedure. 

a. Definitions 

Section 3 of AHRI 920–2020 and 

section 3 of ANSI/ASHRAE 198–2013 

define terms used in the industry 

consensus test standards for DDX– 

DOASes. DOE reviewed these sections 

and is proposing generally to adopt the 

definitions in section 3 of AHRI 920– 

2020 (as enumerated in section 2.2.1(a) 

of proposed Appendix B). As discussed, 

DOE is proposing definitions in the test 

procedure provisions for ‘‘direct 

expansion-dedicated outdoor air system, 

or DX–DOAS’’ as a category of 

commercial package air conditioning 

and heating equipment, and 

‘‘dehumidifying direct expansiondedicated outdoor air system, or DDX– 

DOAS,’’ as a subset of DX–DOAS. 

As discussed in the following 

paragraphs DOE is also proposing to 

define ‘‘integrated seasonal coefficient 

of performance 2, or ISCOP2,’’ 

‘‘integrated seasonal moisture removal 

efficiency 2, or ISMRE2,’’ and 

‘‘ventilation energy recovery system, or 

VERS.’’ In section 1.1 of Appendix B, 

DOE proposes to provide that where any 

definitions conflict between AHRI 920– 

2020 (or any of the industry standards 

referenced) and the CFR, the CFR 

provisions control. 

DOE notes that 10 CFR 431.92 

includes definitions for the efficiency 

metrics used for commercial package air 

conditioners and heat pumps. 

Consistent with this approach, DOE is 

proposing definitions at 10 CFR 431.92 

for ‘‘integrated seasonal coefficient of 

performance 2, or ISCOP2’’ and 

‘‘integrated seasonal moisture removal 

efficiency 2, or ISMRE2’’ that are 

consistent with the definitions for these 

metrics defined in sections 3.12 and 

3.13 of AHRI 920–2020 and that 

specifically reference the DDX–DOAS 

test procedure in proposed Appendix B. 

A ‘‘ventilation energy recovery 

system’’ (VERS) pre-conditions the 

outdoor air before it enters the 

conditioning coil, thereby reducing the 

cooling, dehumidification, or heating 

load on the refrigeration system of the 

DDX–DOAS. ASHRAE Standard 90.1– 

2019 specifies separate equipment 

classes and minimum efficiency levels 

for DDX–DOASes with VERS 

equipment. DOE notes that neither a 

definition for a VERS nor a different 

term for this system is included in the 

previous test standards ANSI/AHRI 

920–2015 and ANSI/ASHRAE 198– 

2013. However, AHRI 920–2020 does 

include a definition for VERS. DOE 

proposes, consistent with AHRI 920– 

2020, to define a VERS as a system that 

preconditions outdoor ventilation air 

entering the equipment through direct 

or indirect thermal and/or moisture 

exchange with the exhaust air, which is 

defined as the building air being 

exhausted to the outside from the 

equipment. 

A VERS may also be used by 

commercial air-conditioning equipment 

other than DDX–DOASes. However, for 

commercial air-conditioning equipment 

other than DDX–DOASes, neither 

ASHRAE Standard 90.1–2019 nor the 

DOE energy conservation standards 

establish equipment classes based on 

the presence of VERS. Under the DOE 

test procedures for commercial package 

air conditioners and heat pump 

equipment other than DDX–DOASes, 

VERS is a feature that is not installed for 

testing. Because an understanding of 

VERS may be relevant to commercial 

package air conditioners and heat 

pumps other than the proposed DDX– 

DOAS category of equipment, DOE is 

proposing to establish a definition of 

VERS, consistent with AHRI 920–2020, 

in 10 CFR 431.92 so that it is broadly 

applicable when used in reference to 

both DDX–DOASes as well as other 

commercial package air conditioning 

and heat pump equipment. 

Additionally, DOE is proposing to 

amend the definition of ‘‘commercial 

HVAC & WH product’’ at 10 CFR 431.2 

to explicitly include DDX–DOAS. 

Issue–5: DOE requests comment on 

the terminology DOE proposes to use for 

DDX–DOASes, including ‘‘integrated 

seasonal coefficient of performance 2, or 

ISCOP2;’’ ‘‘integrated seasonal moisture 

removal efficiency 2, or ISMRE2;’’ and 

‘‘ventilation energy recovery system, or 

VERS.’’ 

In the July 2017 ASHRAE TP RFI, 

DOE sought clarification on the 

difference between a reheat system and 

supplementary heat in ANSI/AHRI 920– 

2015 and ANSI/ASHRAE 198–2013. 82 

FR 34427, 34436 (July 25, 2017). The 

definition for supplementary heat 

provided in section 3.21 of ANSI/AHRI 

920–2015 does not state whether it 

includes heat provided by reheat 

systems such as wrap-around heat pipes 

and wrap-around vapor compression 

systems. 

In response to the July 2017 ASHRAE 

TP RFI, AHRI suggested a revised 

definition for ‘‘supplementary heat’’ that 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36030 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

excludes heat provided by the vapor 

compression cycle or a sub-system that 

transfers heat from one part of the unit 

to another (e.g., wrap-around heat pipe, 

wrap-around vapor compression 

system). (AHRI, No. 11 at p. 11) 

DOE notes that section 3.25 of AHRI 

920–2020 has clarified this issue by 

defining ‘‘supplementary heat’’ to 

exclude a system that transfers heat 

from the outdoor air to the supply air. 

The AHRI 920–2020 definition 

distinguishes reheat provided by a 

vapor compression cycle that is driving 

the dehumidification process from 

common supplementary heat options 

such as fuel-fired heating, steam or hot 

water heating coils, and electric 

resistance. Further, section 3.25 of AHRI 

920–2020 also states that reheat 

provided by secondary heat pumps, 

wrap around heat pumps, or wrap 

around heat pipes are not considered as 

supplementary heat. As discussed, DOE 

proposes to adopt the definition for 

‘‘supplementary heat’’ provided in 

section 3.25 of AHRI 920–2020, as 

enumerated in section 2.2.1(a) of the 

proposed Appendix B, which references 

section 3 of AHRI 920–2020. 

b. Break-In Period 

As part of the DOE test procedures for 

other commercial package air 

conditioners and heat pumps, DOE 

provides the option for a ‘‘break-in’’ 

period, not to exceed 20 hours, with no 

ambient temperature requirements, 

prior to performing a test. See 10 CFR 

431.96(c). This is intended to allow the 

unit to achieve optimal performance 

prior to the test. Neither ANSI/AHRI 

920–2015 nor ANSI/ASHRAE 198–2013 

specify a break-in period for testing 

DDX–DOASes. In response to the July 

2017 ASHRAE TP RFI, AHRI 

commented that proper compressor 

break-in must be allowed to provide a 

fair and accurate test. AHRI also stated 

that it had previously submitted 

comments that 16 hours is not 

sufficient. (AHRI, No. 11 at p. 20) 

DOE addressed comments previously 

submitted by AHRI that DOE should 

require a minimum 16-hour break-in 

period for all commercial air 

conditioning equipment as part of the 

rulemaking finalized in a May 16, 2012 

final rule for energy conservation 

standards and test procedures for 

commercial heating, air-conditioning, 

and water-heating equipment. 77 FR 

28928, 28943. As part of that final rule, 

DOE determined that adopting a 

minimum break-in period of 16 hours 

would unnecessarily increase testing 

costs for manufacturers of equipment 

that can achieve stability in less than 16 

hours. In recognition that different 

equipment will require different 

amounts of break-in time to achieve 

optimal performance and that break-in 

periods of longer than 16 hours may be 

required for some equipment, DOE 

adopted an optional break-in period up 

to a maximum period of 20 hours to 

allow the unit to achieve optimal 

performance before testing for 

commercial air conditioning and 

heating equipment. 77 FR 28928, 

28943–28944 (May 16, 2012). Section 

5.6 of AHRI 920–2020 incorporates the 

same break-in period provision, not to 

exceed 20 hours. Therefore, DOE 

proposes to adopt the optional break-in 

period up to a maximum of 20 hours for 

DDX–DOASes specified in AHRI 920– 

2020 (section 5.6 Break-in), as 

enumerated in section 2.2.1(b) of the 

proposed Appendix B, which references 

section 5 of AHRI 920–2020. 

c. Airflow-Measuring Apparatus 

Figures 1 and 2 of ANSI/ASHRAE 

198–2013 present the typical test set-up 

for DDX–DOASes with and without 

energy recovery. The figures show 

airflow and condition measuring 

apparatus at both the inlet and the 

outlet ends of each airflow path (i.e., the 

outdoor/supply and return/exhaust 

paths). DOE stated in the July 2017 

ASHRAE TP RFI that it is not clear 

whether airflow-measuring apparatus 

are required for both entering and 

leaving air of each airflow path. 82 FR 

34427, 34439 (July 25, 2017). DOE 

requested comment on whether it is 

beneficial or necessary to use two 

airflow-measuring apparatus per 

airstream when testing DDX–DOAS 

equipment. Id. 

AHRI and Carrier both commented 

that using two airflow devices per 

airstream would be difficult and costly 

due to challenges with space 

constraints, additional physical barriers 

that can increase temperature 

stratification in the test chamber, and 

issues associated with meeting the 

specified design conditions due to fan 

reheat energy in the airflow measuring 

stations. (AHRI, No. 11 at p. 19; Carrier, 

No. 6 at p. 7) AHRI further commented 

that while additional airflow measuring 

stations have the benefit of monitoring 

cross-leakage or general leakage in the 

cabinet, it makes testing difficult, if not 

impossible, to perform. (AHRI, No. 11 at 

p. 19) None of the commenters 

indicated that use of two airflowmeasuring apparatus per airflow path is 

necessary to obtain accurate 

measurements. 

Based on comments from AHRI and 

Carrier, DOE tentatively concludes that 

requiring two airflow-measuring 

apparatus per airflow path may be 

unduly burdensome for certain 

manufacturers. However, DOE also 

recognizes that the additional 

measurements may provide an 

indication of crossflow and/or leakage. 

DOE has tentatively concluded that 

AHRI 920–2020 offers a more suitable 

approach to airflow measurement, for 

the reasons that follow. Section C2.2 of 

AHRI 920–2020 requires just one 

airflow-measuring apparatus per airflow 

path. To provide a check for general 

cabinet leakage, section C5.1 of AHRI 

920–2020 specifies a methodology for 

performing a secondary capacity 

measurement that does not require a 

second airflow-measuring apparatus 

(rather, the methodology for verifying 

dehumidification capacity is based on a 

measurement of the weight of collected 

condensate). The requirement for just 

one airflow-measuring apparatus per 

airflow path is consistent with the DOE 

test procedures for all other commercial 

and residential air-conditioning and 

heating systems and limits the testing 

costs and burden on manufacturers. 

Regarding the commenters’ concern 

that the fan heat of the airflowmeasuring apparatus might affect the 

controlled air conditions, DOE 

recognizes that this could affect the 

temperature of the return air entering 

the DDX–DOAS under test. A similar 

issue could occur when duct-inlet 

booster fans are used for moving 

outdoor air either to the outdoor 

ventilation air inlet from a separate 

room, or when moving desiccant 

regeneration air from another room. On 

this topic, section C3.2.2 of AHRI 920– 

2020 specifies that in such 

circumstances, the air conditions are to 

be measured downstream of the fan and 

that the sampled air used for the air 

condition measurement be returned: (a) 

To a location between the flow nozzles 

and the fan of a return airflowmeasuring apparatus, or (b) to the 

separate room from which air is drawn 

when a boost fan is used in the inlet 

duct. Accordingly, in this NOPR, DOE is 

proposing to adopt the provisions for 

the airflow-measuring apparatus 

specified in AHRI 920–2020 section 

C2.2, ‘‘Use of a Single Airflow Rate 

Measuring Apparatus per Airflow Path’’ 

in Appendix C of AHRI 920–2020 

(rather than the dual measurement 

apparatus specifications in Figures 1 

and 2 of ANSI/ASHRAE 198–2013), as 

enumerated in section 2.2.1(f) of the 

proposed Appendix B, which references 

Appendix C of AHRI 920–2020. 

d. Test Operating Conditions 

Through incorporation by reference of 

AHRI 920–2020, DOE is proposing to 

adopt the test operating conditions 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36031 

22Section 6.1.3 of AHRI 920–2020 includes an 

adjustment for maximum supply air dew point 

temperature to increase linearly as barometric 

pressure decreases, up to 57.3 °F at the minimumallowed 13.7 psia test pressure. 

specified in AHRI 920–2020 for DDX– 

DOAS units. These include: (1) 

Standard Rating Conditions (Tables 4 

and 5 of section 6 of AHRI 920–2020, as 

enumerated in section 2.2.1(c) of the 

proposed Appendix B, which references 

section 6 of AHRI 920–2020 omitting 

sections 6.1.2 and 6.6.1); (2) simulated 

ventilation air conditions for testing 

under Option 2 for DDX–DOASes with 

VERS (section 5 of AHRI 920–2020 

(which includes section 5.4.1.2 Option 

2), as enumerated in section 2.2.1(b) of 

the proposed Appendix B, which 

references section 5 of AHRI 920–2020); 

(3) atmospheric pressure (section 5 of 

AHRI 920–2020 (which includes section 

5.10 Atmospheric Pressure), as 

enumerated in section 2.2.1(b) of the 

proposed Appendix B); (4) target supply 

air conditions (section 6 of AHRI 920– 

2020 (which includes section 6.1.3 

Supply Air Dewpoint Temperature and 

section 6.1.4 Supply Air Dry Bulb 

Temperature), as enumerated in section 

2.2.1(c) of the proposed Appendix B); 

(5) external static pressure (section 6 of 

AHRI 920–2020 (which includes section 

6.1.5.6 External Static Pressure), as 

enumerated in section 2.2.1(c) of the 

proposed Appendix B); and (6) target 

supply and return airflow rates (section 

6 of AHRI 920–2020 (which includes 

section 6.1.5 Supply and Return Airflow 

Rates), as enumerated in section 2.2.1(c) 

of the proposed Appendix B). 

DOE received comments from 

interested parties regarding target 

supply and return airflow rates and 

target supply air conditions in response 

to the July 2017 ASHRAE TP RFI, and 

the following section discusses these 

specific issues. 

i. Target Supply and Return Airflow 

Rates 

Section 5.2.2 of ANSI/AHRI 920–2015 

and section 8.1 of ANSI/ASHRAE 198– 

2013 require the supply airflow rate to 

be set in accordance with manufacturer 

specifications. In the July 2017 ASHRAE 

TP RFI, DOE observed that many DDX– 

DOAS models are capable of operating 

over a range of airflow rates. 82 FR 

34427, 34437 (July 25, 2017). DOE 

expects these models to have supply air 

fans that can be configured with a range 

of speeds to accommodate the airflow 

range and the variation in duct length in 

field installations. Id. The performance 

of these models may also vary 

significantly from the low end to the 

high end of the specified airflow range. 

As part of the July 2017 ASHRAE TP 

RFI, DOE sought comments on how 

manufacturers select the airflow rate for 

testing, given the large range of airflows 

that are typical of DDX–DOAS units. Id. 

In response to this issue, AHRI 

commented that the optimum-efficiency 

airflow varies with each application and 

that the manufacturer should specify the 

design airflow rate as long as it achieves 

the 55 °F dew point temperature. (AHRI, 

No. 11 at pp. 13–14) The approach 

described by AHRI is consistent with 

the approach of AHRI 920–2020, which 

stipulates the use of the manufacturerspecified airflow in section 6.1.5 of that 

document. This section of AHRI 920– 

2020 also addresses how to set the 

airflow when it is not specified by the 

manufacturer and the case where the 

dehumidification provided is not 

consistent with DDX–DOAS 

performance (i.e., provision of supply 

air at 55 °F or lower dew point, when 

using the manufacturer-specified 

airflow).22

As discussed, DOE is proposing to 

adopt the provisions in section 6.1.3 

and 6.1.5 of AHRI 920–2020, which 

specify that the target supply airflow 

rate be the manufacturer-specified 

airflow rate and that, for Standard 

Rating Condition A, achieves 

dehumidification consistent with 

providing a 55 °F dew point temperature 

in standard atmospheric pressure 

conditions. In cases where supply 

airflow is not specified by the 

manufacturer, or supply air dew point 

exceeds the maximum when using the 

manufacturer-specified airflow, AHRI 

920–2020 requires setting airflow for 

Standard Rating Condition A such that 

the supply air dew point does not 

exceed the maximum. 

ii. Units With Cycle Reheat Functions 

As part of the July 2017 RFI, DOE 

noted that provisions regarding reheat 

and the supplementary heat penalty 

specified in ANSI/AHRI 920–2015 and 

ANSI/ASHRAE 198–2013 were unclear. 

82 FR 34427, 34436 (July 25, 2017). 

Most of the DDX–DOAS models that are 

equipped with the capability to reheat 

dehumidified air to space-neutral 

conditions use hot refrigerant gas 

discharged by the compressor to reheat 

the dehumidified air leaving the 

evaporator coil. Other approaches can 

also be used to transfer heat from one 

part of the DDX–DOAS to another. 

(Section 3.21.1 of AHRI 920–2020 

defines all of these methods as ‘‘cycle 

reheat.’’) Reheat may also be provided 

by supplementary heat sources, such as 

a gas furnace or an electric resistance 

heater, but these are not considered 

cycle reheat. A discussion of cycle 

reheat capability with respect to the 

scope of this test procedure is provided 

in section III.A.4 of this document, and 

a discussion of the supplementary heat 

penalty is provided in section III.B.3.a 

of this document. 

ANSI/AHRI 920–2015 requires that 

supply air dew point temperature be 

55 °F or lower, which generally means 

(i.e., for a DDX–DOAS that removes 

moisture by latent cooling without the 

use of desiccants) that the air must be 

cooled to a temperature that is, at most, 

a few degrees above 55 °F. Section 6 of 

ANSI/AHRI 920–2015 does not 

explicitly require testing with reheat 

turned on, but note 3 to Table 2 and 

note 3 to Table 3 of that industry 

standard require the DDX–DOAS to 

condition supply air to a minimum drybulb temperature of 70 °F for all 

dehumidification and heating tests— 

and this would have to be accomplished 

with active reheat (as discussed in the 

following paragraphs). Further, for units 

unable to meet this minimum threshold, 

section 6.1.3.1 of ANSI/AHRI 920–2015 

specifies the application of a 

supplementary heat penalty to represent 

the power input that would be required 

to heat the supply air to the 70 °F target 

using electric resistance heating. 

DOE noted in the July 2017 RFI that 

ANSI/ASHRAE 198–2013 includes two 

dehumidification tests, one with cycle 

reheat functions turned on and the other 

with cycle reheat functions turned off 

(sections 8.3.1.1 and 8.3.1.2, 

respectively). DOE further noted that 

ANSI/AHRI 920–2015 does not, 

however, specify which of these values 

is used in the calculation of ISMRE. 82 

FR 34427, 34436 (July 25, 2017). 

As part of the July 2017 ASHRAE TP 

RFI, DOE requested comment on 

whether the dehumidification test with 

cycle reheat on or off should be used to 

calculate ISMRE, and how and when the 

supplementary heat penalty is applied. 

82 FR 34427, 34436 (July 25, 2017). 

AHRI commented that the 

dehumidification efficiency metrics 

specified in ANSI/AHRI 920–2015 are 

based on supply air at a dry-bulb 

temperature of 70 °F, and if the unit 

requires reheat to be on (as described in 

ANSI/ASHRAE 198–2013) for supply air 

temperature control, then this reheat-on 

test is needed to determine 

dehumidification capacity and 

efficiency. (AHRI, No. 11 at p. 11) DOE 

understands AHRI’s comment to mean 

that ANSI/AHRI 920–2015 effectively 

requires cycle reheat to be activated 

during dehumidification tests in order 

to meet both the supply air dew point 

and dry-bulb temperature requirements. 

In contrast to ANSI/AHRI 920–2015, 

AHRI 920–2020 more explicitly 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36032 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

addresses the use of cycle reheat for 

dehumidification tests and provides 

more information on when the 

supplementary heat penalty should be 

used. As discussed in section III.B.2.a of 

this NOPR, DOE is proposing to adopt 

the revised MRE and ISMRE2 metrics 

specified in AHRI 920–2020, which do 

not include a supplementary heat 

penalty. Section 6.1.4.2 of AHRI 920– 

2020 specifies that when determining 

MRE and ISMRE2, the manufacturer 

shall specify whether cycle reheat is to 

be activated for the test. As discussed in 

section III.B.2.a of this document, AHRI 

920–2020 provides separate application 

metrics (i.e., MRE70 and ISMRE270) 

which may be used for representations 

and which require a supply air dry-bulb 

temperature above 70 °F (and below 

75 °F). For these separate application 

metrics, if cycle reheat cannot achieve 

70 °F, a supplementary heat penalty is 

applied based on raising the supply air 

dry-bulb temperature up to 70 °F (see 

section 6.1.4.1 of AHRI 920–2020). DOE 

has tentatively determined that these 

provisions in AHRI 920–2020 clarify the 

requirements for cycle reheat and the 

supplementary heat penalty, so the 

Department is proposing to adopt these 

provisions in this NOPR (section 6 of 

AHRI 920–2020, as enumerated in 

section 2.2.1(c) of the proposed 

Appendix B). 

iii. Target Supply Air Dry-Bulb 

Temperature 

As discussed, in the July 2017 

ASHRAE TP RFI, DOE noted that ANSI/ 

AHRI 920–2015 includes a requirement 

of minimum supply air temperature of 

70.0 °F for all Standard Rating 

Conditions and a maximum dew-point 

temperature of 55.0 °F for Standard 

Rating Conditions for dehumidification. 

In that document, DOE further noted 

that ANSI/ASHRAE 198–2013 requires a 

supply air temperature of 75.2 °F or as 

close to this value as the controls will 

allow during testing. As part of the July 

2017 ASHRAE TP RFI, DOE requested 

comment on the difference in target 

supply air temperature requirements 

between ANSI/AHRI 920–2015 and 

ANSI/ASHRAE 198–2013, and the 

appropriate supply air temperature for 

use in the DOE test procedure for DDX– 

DOASes. 82 FR 34427, 34438 (July 25, 

2017). 

AHRI and Goodman commented that 

the minimum supply air temperature 

should be 70 °F. AHRI added that ANSI/ 

ASHRAE 198–2013, which was 

developed based on previous versions of 

AHRI 920 that required a supply air 

temperature of 75 °F, is being updated to 

reflect the new value of 70 °F. (AHRI, 

No. 11 at p. 17; Goodman, No. 14 at p. 

2) 

As discussed in the previous 

subsection, DOE proposes to incorporate 

by reference the provisions in section 

6.1.4 of AHRI 920–2020, which specifies 

setting the supply air dry-bulb 

temperature to within a range of 70– 

75 °F for tests to determine 

dehumidification metrics. For all 

dehumidification tests, 75 °F represents 

the maximum supply air dry-bulb 

temperature above which a 

supplementary cooling penalty must be 

applied. As noted in section III.B.3.d.ii 

of this NOPR, a supplementary heat 

penalty must be applied for ISCOP2 

calculations when the minimum supply 

air dry-bulb temperature of 70 °F cannot 

be met in heating mode. 

iv. Target Supply Air Dew-Point 

Temperature 

Note 5 to Table 2 and note 6 to Table 

3 in ANSI/AHRI 920–2015 state that the 

maximum dew point for Standard 

Rating Conditions A through D shall be 

55.0 °F. The industry consensus 

standard does not specify whether these 

conditions apply to the outdoor air, 

supply air, or return air. DOE interprets 

these requirements to apply to the 

supply air because the humidity levels 

for outdoor air and return air are already 

specified in the same tables. 

Furthermore, although ANSI/AHRI 

920–2015 specifies a maximum dew 

point temperature, the industry test 

standard does not include requirements 

to ensure that the dew-point 

temperature is maintained at the same 

level while testing at the different 

Standard Rating Conditions specified in 

ANSI/AHRI 920–2015. Many DDX– 

DOASes are equipped with modulating/ 

variable capacity compressors, thereby 

allowing control for a given supply air 

dew point temperature. Allowing a 

lower dew point temperature for 

Standard Rating Conditions B, C, and D 

specified in ANSI/AHRI 920–2015 

could give a better MRE rating for those 

test points, but the unit would use more 

energy to the extent it provides 

unnecessary excess dehumidification if 

operated in that manner. DOE also 

recognizes that the conditioned space 

latent cooling requirements for Standard 

Rating Condition A specified in ANSI/ 

AHRI 920–2015 represent the worst-case 

scenario, so there would be no need to 

deliver a lower dew point (i.e., excess 

dehumidification) for Standard Rating 

Conditions B, C, and D. AHRI 920–2020 

revises the supply air dew point 

requirements. Section 6.1.3 of AHRI 

920–2020 requires that the average 

supply air dew point for Standard 

Rating Condition B, C, and D must be 

within 0.3 °F of the Standard Rating 

Condition A dew point value. 

Accordingly, in this NOPR, DOE 

proposes to adopt the relevant 

provisions found in section 6.1.3 in 

AHRI 920–2020, which explicitly state 

that the supply air dew point 

temperature shall be 55.0 °F or below for 

all Standard Rating Conditions A 

through D when operated at a 

barometric pressure of 29.92 in Hg, and 

that the supply air dew point 

temperature for Standard Rating 

Conditions B, C, and D must be within 

0.3 °F of the measured supply air dew 

point temperature for Standard Rating 

Condition A, as noted above. 

v. Units With Staged Capacity Control 

During testing, DDX–DOAS units with 

modulating compressors may be able to 

achieve supply air conditions within the 

proposed tolerances of the target 

conditions for Standard Rating 

Conditions B, C, and D. However, units 

with staged capacity will not likely be 

able to do this because they control 

capacity in larger increments. DDX– 

DOAS units with staged capacity or 

reheat control unable to maintain stable 

operation at the proposed dry-bulb and 

dew-point temperature targets within 

proposed tolerances would have to 

cycle between two stages (or cycle 

between the compressor(s) being on and 

off) to deliver average conditioning 

consistent with the target. 

Neither ANSI/AHRI 920–2015 nor 

ANSI/ASHRAE 198–2013 have 

provisions to address units that cycle. In 

response to the July 2017 ASHRAE TP 

RFI, AHRI commented that the time 

average testing method suggested by 

DOE in its initial review section 6.6 of 

ANSI/AHRI 920–2015 would prevent 

credit for over-dehumidifying at 

Standard Rating Conditions B, C, and D, 

but is excessively complex. Instead, 

AHRI recommended a calculated 

adjustment that does not credit moisture 

removal in excess of the Standard 

Rating Condition A design dew-point 

temperature. (AHRI, No. 11 at p. 20) 

This issue has now largely been 

addressed in AHRI 920–2020. 

Specifically, section 6 of AHRI 920– 

2020 prescribes a method to address 

DDX–DOASes with staged capacity 

control that is consistent with the 

aforementioned method of DOE’s initial 

review. It differs from DOE’s suggested 

method in that it applies the weighted 

averaging on the basis of the supply air 

humidity ratio rather than the dew 

point, and that it applies any applicable 

supplementary cooling or heat penalty 

to operation at each particular stage 

rather than after determination of a 

weighted average supply air dry-bulb 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36033 

23 In the context of ANSI/AHRI 920–2015, an 

application configuration specifies test conditions 

based on the expected application of the DDX– 

DOAS. 

temperature. Given the development of 

defined test requirements and equations 

addressing over-dehumidification, DOE 

initially concludes that the method in 

AHRI 920–2020 is not excessively 

complex. AHRI 920–2020 requires that 

when testing DDX–DOASes with staged 

capacity control in a dehumidification 

test condition having a supply condition 

dew point target (e.g., Conditions B, C, 

or D), if the dew point temperature 

cannot be controlled within the 

specified test tolerances for a given partload condition, a weighted average of 

the results of two tests that bracket the 

target dew point temperature will be 

used. In this NOPR, DOE is proposing 

to adopt the provisions in section 6 of 

AHRI 920–2020 for achieving the target 

supply air conditions for units with 

staged capacity control. 

Staging of compressor capacity may 

also affect operation in heating mode. 

Section 6 of AHRI 920–2020 prescribes 

methods for determining COP to 

account for cycling between compressor 

stages, or for operation when the lowestcapacity compressor stage provides 

more capacity than required to heat the 

supply air to 75 °F. These methods are 

similar to the AHRI 920–2020 method 

for addressing staged compressor 

capacity for dehumidification. 

Accordingly, DOE proposes to adopt the 

provisions in AHRI 920–2020 for staged 

capacity heat pump DDX–DOASes in 

heating mode. 

e. Water-Cooled and Water-Source Heat 

Pump DX–DOAS Equipment 

i. Test Conditions for Multiple-Inlet 

Water Sources 

As discussed in the July 2017 

ASHRAE TP RFI, the inlet water 

temperatures in ANSI/AHRI 920–2015 

Table 2 for testing water-cooled DDX– 

DOASes differ from the water-source 

heat pump inlet temperature conditions 

specified in Table 3 for water-source 

heat pump DDX–DOASes tested using 

the ‘‘water source’’ test conditions. DOE 

requested comment on the need for 

different dehumidification test 

conditions for a water-cooled DDX– 

DOAS as compared to a water-source 

heat pump DDX–DOAS using the closed 

water loop test conditions. 82 FR 34427, 

34438 (July 25, 2017). In the July 2017 

ASHRAE TP RFI, DOE also pointed out 

that Tables 2 and 3 in ANSI/AHRI 920– 

2015 include two application 

configurations 23 for water-cooled DDX– 

DOASes and three application 

configurations for water-source heat 

pump DDX–DOASes. Id. DOE notes that 

ASHRAE 90.1–2016 established 

different standards for each of these five 

application configurations. 

In response to the July 2017 ASHRAE 

TP RFI on this issue, AHRI commented 

that the two sets of water temperatures 

for water-cooled DDX–DOASes and 

water-source heat pump DDX–DOASes 

should be identical and that the 

differences would be resolved in an 

update to ANSI/AHRI 920–2015. (AHRI, 

No. 11 at p. 17) AHRI also commented 

that in almost all cases, a single design 

is used for water-cooled equipment used 

with cooling tower water and chilled 

water, and, similarly, a single design is 

used for all of the water-source 

applications, adding that for each of 

these cases, a single set of water 

conditions can be used for testing. AHRI 

recommended that the various entering 

water and inlet fluid conditions remain 

as presented in the ANSI/AHRI 920– 

2015 standard, but any regulated 

products are to be tested to the ‘‘Chilled 

Water Entering Condenser 

Temperature’’ column values in Table 2 

and the ‘‘Water Source Heat Pumps’’ 

column values in Table 3. (AHRI, No. 11 

at p. 17) 

In response, DOE notes that AHRI 

920–2020 still provides separate inlet 

fluid rating conditions for the different 

water-cooled and water-source heat 

pump DDX–DOAS applications but now 

identifies some as optional application 

rating conditions. In light of the 

retention of these separate inlet fluid 

rating conditions in AHRI 920–2020, 

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 during the course of 

developing that industry consensus 

standard. Table 4 of AHRI 920–2020 

continues to include separate inlet fluid 

rating conditions for water-cooled 

cooling tower and water-cooled chilled 

water DDX–DOASes, but Note 3 to 

Table 4 of AHRI 920–2020 indicates that 

the water-cooled chilled water 

condition is the optional application 

rating condition, contrary to AHRI’s 

recommendation in response to the July 

2017 ASHRAE TP RFI. Table 5 of AHRI 

920–2020 includes separate inlet fluid 

rating conditions for water-source and 

ground-source closed-loop heat pump 

DDX–DOASes but identifies the groundsource closed-loop conditions as the 

optional application rating condition. 

Tables 4 and 5 of AHRI 920–2020 also 

revise the inlet temperatures of the 

rating conditions for water-cooled 

cooling tower, water-source heat pump, 

and water-source ground-source closedloop heat pump DDX–DOASes. In this 

NOPR, DOE is proposing to adopt the 

water/fluid rating conditions provided 

in AHRI 920–2020 (section 6 of AHRI 

920–2020, which includes Table 4 and 

Table 5, as enumerated in section 

2.2.1(c) and 2.2.2 of the proposed 

Appendix B), including the chilled 

water and ground-source closed-loop 

conditions specified as optional in 

AHRI 920–2020 so as to allow for 

voluntary representations for those 

applications. In any future energy 

conservation standards rulemaking for 

DDX–DOASes, DOE would consider 

establishing standards and the 

corresponding certification 

requirements in the context of the inlet 

fluid temperature conditions specific for 

water-cooled cooling towers and for 

water-source heat pumps provided in 

Table 4 and Table 5 of AHRI 920–2020, 

respectively. 

ii. Condenser Liquid Flow Rate 

In the July 2017 ASHRAE TP RFI, 

DOE noted that ANSI/AHRI 920–2015 

provides instructions for setting the 

condenser liquid flow rate in section 

6.1.4 and condenser liquid entering 

temperature in Tables 2 and 3 when 

conducting the dehumidification test for 

water-cooled and water-source heat 

pump DDX–DOASes. 82 FR 34427, 

34437 (July 25, 2017). Section 6.1.4 of 

ANSI/AHRI 920–2015 indicates to use 

the liquid flow rates ‘‘specified by the 

manufacturer.’’ The manufacturer must 

specify a single liquid flow rate for tests 

at all Standard Rating Conditions as 

defined in ANSI/AHRI 920–2015, unless 

the unit is equipped with automatic 

control of the liquid flow rate. 

In the July 2017 ASHRAE TP RFI, 

DOE noted that ANSI/AHRI 340/360– 

2007 and ANSI/AHRI 210/240–2008, 

which are incorporated by reference as 

DOE’s test procedures for rating watercooled commercial air-conditioning 

equipment, specify inlet and outlet 

water temperature requirements rather 

than relying on manufacturers to 

determine water flow rate. Further, both 

of these industry consensus standards 

specify that the full-load water flow rate 

determined for the Standard Rating 

Conditions should also be used for partload rating conditions. DOE further 

stated in the July 2017 ASHRAE TP RFI 

that these test methods reflect the 

typical design temperature differential 

for cooling towers serving water-cooled 

equipment, and they are very common 

for control of condenser water pumps; 

hence, it is not clear to DOE why the 

same test method would not be adopted 

for water-cooled DDX–DOAS. 82 FR 

34427, 34437 (July 25 2017). As part of 

the July 2017 ASHRAE TP RFI, DOE 

requested information on how 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36034 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

24 ‘‘External head pressure’’ reflects the pump 

power output, in that it represents the height to 

which the pump can raise the water if the water 

were being moved opposite the force of gravity. 

condenser water flow rates are set in the 

field, how they are controlled at partload, and whether the relevant 

provisions in ANSI/AHRI 920–2015 

provide sufficient guidance regarding 

how to set up water flow for DDX– 

DOASes with automatic water flow 

control systems. Id. 

AHRI and Carrier commented that the 

condenser water flow rates should be set 

by the manufacturer or the installation 

instructions, consistent with ANSI/ 

AHRI 920–2015. (AHRI, No. 11 at p. 15; 

Carrier, No. 6 at p. 5) Carrier added that 

for part-load conditions, setting the 

condenser water flow rate will depend 

on what is needed for head pressure 

control, and that this should be defined 

in the installation instructions and 

followed for the test. Carrier stated that 

some equipment may require no control 

and that others may use head pressure 

flow regulating valves. (Carrier, No. 6 at 

p. 5) AHRI argued that any variation in 

flow rate that occurs automatically 

based on the operation and the 

equipment design will be measured 

during testing, with the pressure drop at 

that flow rate also being measured. 

AHRI indicated that the pumping 

penalty accounts for different 

manufacturer specifications of flow 

rates and pressure drop at each of the 

test conditions. (AHRI, No. 11 at p. 15) 

As part of its update to the industry 

consensus test standard for DDX– 

DOASes, AHRI added additional 

requirements for liquid flow rate. More 

specifically, while section 6.1.6.1 of 

AHRI 920–2020 continues to provide 

that the water flow rate be specified by 

the manufacturer, the test method now 

adds that it must deliver a liquid 

temperature rise no less than 8 °F when 

testing under Standard Rating Condition 

A. Section 6.1.6.2 of AHRI 920–2020 

requires that the flow rate set under 

Standard Rating Condition A be used for 

testing at the remaining Standard Rating 

Conditions (B through F), unless 

automatic adjustment of the liquid flow 

rate is provided by the equipment. 

Section 6.1.6.2 of AHRI 920–2020 also 

requires that if condenser water flow 

rate is modulated under part-load 

conditions, the flow rate must not 

exceed the flow rate set for Condition A. 

DOE has tentatively concluded that 

the addition of a minimum temperature 

differential in AHRI 920–2020 better 

reflects control strategies for cooling 

towers serving water-cooled equipment 

and for condenser water pumps while 

still leaving flexibility for manufacturers 

to specify full-load flow rate and to 

implement options for modulating flow 

rate at part-load conditions. The 

Department notes that the provision 

allowing for automatic adjustment of the 

liquid flow rate for part-load tests 

accounts for manufacturer control 

strategies, such as condenser head 

pressure control, and is also accounted 

for in the water pump effect (discussed 

in the following section). DOE has 

tentatively concluded that these 

provisions would be representative of 

flow rates during an average use cycle 

and would not be unduly burdensome 

to conduct. Therefore, DOE is proposing 

to adopt the liquid flow requirements in 

AHRI 920–2020 for water-cooled and 

water-source heat pump DDX–DOASes 

(section 6 of AHRI 920–2020, which 

includes section 6.1.6 Liquid Flow Rates 

for Water-Cooled, Water-Source Heat 

Pump, and Ground-Source Heat Pump), 

as enumerated in section 2.2.1(c) of the 

proposed Appendix B. 

iii. Water Pump Effect 

As part of the July 2017 ASHRAE TP 

RFI, DOE noted that ANSI/AHRI 920– 

2015 includes an equation for 

calculating the ‘‘water pump effect,’’ 

which is an estimate of the energy 

consumption of non-integral water 

pumps (i.e., pumps that are not part of 

the DDX–DOAS unit and whose power 

consumption would, therefore, not 

already be part of the measured power). 

82 FR 34427, 34438 (July 25 2017). DOE 

noted that section 6.1.3 of ANSI/AHRI 

920–2015 implies that this calculation 

applies solely to water pumps serving 

refrigerant-to-liquid heat recovery 

devices—no indication is given whether 

the equation also applies for pumps 

serving water-source or water-cooled 

condensers—although it is possible that 

the term ‘‘refrigerant-to-liquid heat 

recovery device’’ refers to the condenser 

of a water-source heat pump DDX– 

DOAS. Id. 

In the July 2017 ASHRAE TP RFI, 

DOE requested confirmation that the 

‘‘refrigerant-to-liquid heat recovery 

device’’ cited in section 6.1.3 of ANSI/ 

AHRI 920–2015 is intended to include 

heat exchangers used for heat rejection 

during the dehumidification cycle, and 

comment on whether Equation 1 of this 

section for estimating the energy use of 

water pumps is appropriate for DDX– 

DOASes with water-cooled condensers. 

Id. In its comments, AHRI confirmed 

that the term ‘‘refrigerant-to-liquid heat 

recovery device’’ is intended to include 

liquid-to-refrigerant heat exchangers 

used in the dehumidification cycle and 

heating cycle. (AHRI, No. 11 at p. 16) 

The revisions to the industry 

consensus testing standard in AHRI 

920–2020 clarify this matter and are 

consistent with the public comments 

received. Section 6.1.6.4 of AHRI 920– 

2020 provides the water pump effect 

equation, and section 11.1 of AHRI 920– 

2020 states within the definition of 

symbol PE,x that the water pump effect 

applies to all water-cooled and watersource units without integral water 

pumps. Thus, DOE is proposing to 

adopt the water pump effect provisions 

in sections 6.1.6.4 and 11.1 of AHRI 

920–2020 to account for the energy use 

of water pumps for water-cooled 

condensers, as enumerated in section 

2.2.1(c) and section 2.2.1(d) of the 

proposed Appendix B, which reference 

sections 6 and 11 of AHRI 920–2020, 

respectively. 

In further clarification, the total pump 

effect does not need to be calculated for 

pumps that are integral to the DDX– 

DOAS, because the power for these 

pumps would be measured as part of the 

main DDX–DOAS power measurement. 

Currently, the number of DDX–DOAS 

models on the market with integral 

pumps is very limited. However, AHRI 

920–2020 does not explicitly state the 

amount of external head pressure 24 to 

use when testing DDX–DOASes with 

integral pumps, a necessary parameter. 

DOE notes that the calculation of the 

water pump effect for DDX–DOASes 

without integral pumps specified AHRI 

920–2020 includes a fixed adder of 25 

Watts per gallon per minute based on 20 

feet of water column of external head 

pressure, a value which the Department 

reasons could be suitably applied to 

DDX–DOASes with integral pumps. 

Accordingly, DOE is proposing to 

include additional specifications in 

section 2.2.1(c)(ii) of proposed 

Appendix B that DDX–DOASes with 

integral pumps be configured with an 

external head pressure equal to 20 feet 

of water column (i.e., the same level of 

external head pressure used in the 

calculation of the pump effect for DDX– 

DOASes without integral pumps). 

DOE has initially determined that the 

proposal to specify the same external 

head pressure for integral pumps as the 

external head pressure used in the 

calculation of the pump effect for DDX– 

DOASes without integral pumps is 

consistent with the industry consensus 

test procedure. The proposed 

requirement would provide additional 

direction for treatment of integral 

pumps consistent with the treatment of 

non-integral pumps and would provide 

for the representative comparability of 

results between DDX–DOASes with and 

without integral pumps. To the extent 

the industry test procedure does not 

specify an external head pressure for 

DDX–DOASes with an integral pump, 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36035 

25For example, for a minimally-compliant 

120,000 Btu/h water-cooled unit with gas heat 

having a 12.5 EER (see 10 CFR 431.97 Table 1), the 

total electricity use is 120,000 Btu/h ÷ 11.9 Btu/Wh 

= 10,084 W, and the heat rejection fan adder is 

120,000 Btu/h × (10 W per 1,000 Btu/h) = 1,200 W. 

the industry test procedure would not 

ensure that measured results are 

comparative, and 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 a specification for the 

external head pressure for an integrated 

pump, the industry test procedure 

would not meet the statutory 

requirements of 42 U.S.C. 6314(a)(2)–(3) 

and is, therefore, proposing the 

supplemental specification. 

In addition, DOE is proposing a 

condition tolerance of up to 1 foot of 

water column greater than the 20-foot 

requirement (which equates to 5 

percent), which is equivalent to the 

condition tolerance on air side external 

static pressure in Table 9 of AHRI 920– 

2020 (Test Operating and Test 

Condition Tolerances); namely, the 

provision in that table provides for up 

to 0.05 inch of water column greater 

than the target external static pressure, 

which is around 1 inch of water 

column. Similarly, DOE is proposing an 

operating tolerance of up to 1 foot of 

water column, which is equivalent to 

the operating tolerance on air side 

external static pressure in Table 9 of 

AHRI 920–2020; namely, the provision 

in that table provides for 0.05 inch of 

water column. To the extent the 

industry test procedure does not specify 

a condition tolerance and operating 

tolerance for the water column, the 

industry test procedure would not 

ensure consistent and comparable 

results and 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, in the that 

absence of such tolerances for the water 

column, the industry test procedure 

would not meet the statutory 

requirements of 42 U.S.C. 6314(a)(2)–(3) 

and is, therefore, proposing the 

supplemental specification. 

Issue–6: DOE requests comment on 

the proposal to require that watercooled and water-source DDX–DOASes 

with integral pumps be set up with an 

external pressure rise equal to 20 feet of 

water column with a condition 

tolerance of ¥0/+1 foot and an 

operating tolerance of 1 foot. 

iv. Energy Consumption of Heat 

Rejection Fans and Chillers 

Neither ANSI/AHRI 920–2015 nor 

ANSI/ASHRAE 198–2013 address 

accounting for the energy consumption 

of heat rejection fans (e.g., cooling tower 

fans) for water loops serving the 

condensers of water-cooled DDX– 

DOASes. 82 FR 34427, 34438 (July 25, 

2017). DOE noted that section 6.1 of 

AHRI 340/360–2007, which is used for 

rating certain water-cooled commercial 

package air conditioning and heat pump 

equipment, provides a power 

consumption adjustment for both the 

cooling tower fan and the circulating 

water pump (it is assumed that the 

pump is external to the air conditioning 

equipment). Id. In addition, neither 

ANSI/AHRI 920–2015 nor ANSI/ 

ASHRAE 198–2013 address accounting 

for the energy consumption of chiller 

systems used to provide chilled water to 

DDX–DOASes with chilled-watercooled condensers. In the July 2017 

ASHRAE TP RFI, DOE requested 

comment on accounting for the energy 

consumption for heat-rejection fans and 

chiller systems employed in watercooled or water-loop DDX–DOASes. Id. 

AHRI commented that the AHRI test 

standard for certain commercial package 

air conditioning and heat pump 

equipment includes the cooling tower 

fan and pump energy as part of a flat 

rate adjustment, but that the 

International Organization for 

Standardization (ISO) test standard for 

water-source heat pumps does not 

account for cooling tower fan energy use 

at this time. AHRI stated that the 

minimum efficiency values for DDX– 

DOASes specified in ASHRAE 90.1– 

2016 were based on the current ANSI/ 

AHRI 920–2015 standard that does not 

account for the energy consumption of 

heat-rejection fans or the chiller system, 

although it does account for the 

additional water pumping energy (see 

the discussion of the water pump effect 

in section III.B.3.e.iii of this document). 

AHRI stated that, as a result, DOE 

should not account for this energy in the 

efficiency metric for DDX–DOASes 

because doing so introduces unknown 

impacts on the design and costs 

associated with meeting the minimum 

efficiency requirements. (AHRI, No. 11 

at pp. 16–17) Carrier also commented 

that heat-rejection fans are not part of a 

water-cooled unit but are part of the 

cooling tower rating and are covered by 

Table 6.8.1.7 in ASHRAE 90.1–2016. 

(Carrier, No. 6 at p. 5) Carrier 

commented that chiller system energy 

use should not be included in the 

efficiency metric because this is not a 

system rating and is only a component 

rating method for the DDX–DOAS itself. 

(Carrier, No. 6 at p. 6) 

The revised AHRI 920–2020 also does 

not include energy use of the heatrejection fans and chiller systems 

employed in water-cooled or water-loop 

DDX–DOASes. DOE observes that 

accounting for this energy use is not a 

consistent industry practice, as 

evidenced by the differences between 

the AHRI 340/360–2007 approach for 

more typical commercial package air 

conditioning equipment and the ISO 

approach for water-source heat pumps. 

The heat rejection fan addition for more 

typical water-cooled commercial 

package air conditioning equipment is a 

modest energy adder (around 10 percent 

of unit power).25 Furthermore, 

including the energy of the heat 

rejection fan and chiller systems would 

not help to distinguish between models 

of different efficiency, since the adder 

would be identical for two samecapacity models with different 

efficiencies. For these reasons, and 

consistent with AHRI 920–2020, DOE is 

not proposing in this NOPR to include 

any energy consumption associated 

with heat rejection fans, cooling towers, 

or chiller systems used to cool the water 

loops of water-cooled or water-source 

DDX–DOASes. 

v. Chilled Water Coil Exclusion 

In the July 2017 ASHRAE TP RFI, 

DOE noted that section 2 of ANSI/ 

ASHRAE 198–2013 specifically 

excludes equipment with water coils 

that are supplied by a chiller located 

outside of the unit. 82 FR 34427, 34438 

(July 25 2017). However, Table 2 in 

ANSI/AHRI 920–2015 includes 

operating conditions for which a watercooled condenser is supplied with 

chilled water, and ASHRAE 90.1–2016 

established standard levels for DDX– 

DOASes that operate with chilled water 

as the condenser cooling fluid. As part 

of the July 2017 ASHRAE TP RFI, DOE 

requested confirmation that the ANSI/ 

ASHRAE 198–2013 chiller exclusion 

applies to cooling coils rather than 

condenser coils. Id. 

In response to the July 2017 ASHRAE 

TP RFI, AHRI commented that both 

ANSI/AHRI 920–2015 and ANSI/ 

ASHRAE 198–2013 were designed for 

units that contain vapor compression 

cycle-based cooling and 

dehumidification with direct expansion 

coils. AHRI stated that direct 

application of chilled water coils to cool 

and dehumidify is outside the scope of 

the standard, as the energy for cooling 

is expended at an external source of 

chilled water. (AHRI, No. 11 at p. 18) 

Carrier commented that chillers should 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36036 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

26The T-test is a non-steady-state (transient) test 

that includes measurement of both the heating 

energy use as the outdoor coil accumulates frost 

and the defrost energy use as the unit undergoes 

multiple defrost cycles, as referenced in section 

8.8.3 of ANSI/ASHRAE 37–2009. 

only be used for cooling coils and not 

for condenser heat rejection unless there 

is heat reclaim, and that this should be 

addressed through a building efficiency 

standard such as ASHRAE 90.1. 

(Carrier, No. 6 at p. 7) 

AHRI 920–2020 did not make a 

change to the exclusion of DOASes with 

water coils that are supplied by a chiller 

located outside of the unit; AHRI’s 

comment explains that the exclusion 

exists because chilled water coil units 

that use the chilled water for cooling are 

not DX units, and the industry test 

procedures are only for DOASes with 

DX cooling. ASHRAE Standard 90.1 

does not include standards for non-DX 

DOASes such as those with chilled 

water coils used for cooling. Based on 

AHRI 920–2020, and ANSI/ASHRAE 

198–2013 as referenced, and the 

comments received, DOE did not 

consider DOAS units that use chilled 

water coils directly for cooling and 

dehumidifying. However, the comments 

provided in response to the July 2017 

ASHRAE TP RFI, as discussed in 

section III.B.3.e.i of this document, 

indicate that DX–DOASes and DDX– 

DOASes may still use chilled water for 

condenser coils. (AHRI, No. 11 at p. 17) 

f. Defrost Energy Use for Air-Source 

Heat Pump 

In the July 2017 ASHRAE TP RFI, 

DOE noted that tests conducted at 35 °F 

dry-bulb temperature for consumer 

central air conditioning heat pumps 

(which are air-source) consider the 

impacts of defrosting of the outdoor coil 

in the energy use measurement (see 

section 3.9 of 10 CFR part 430, subpart 

B, appendix M), while defrost is not 

addressed in ANSI/ASHRAE 198–2013. 

82 FR 34427, 34436 (July 25 2017). DOE 

stated that defrost has a real impact on 

efficiency because of energy use 

associated with defrost and because a 

system cannot continue to provide 

heating during defrost operation, 

thereby reducing time-averaged 

capacity. Id. Hence, DOE noted that 

consideration of defrost could provide a 

more field-representative measurement 

of performance. DOE requested 

comment on whether testing for test 

condition E of ANSI/AHRI 920–2015 

Table 2 (i.e., 35 °F dry-bulb/29 °F wetbulb) should consider energy use 

associated with defrost. Id. 

On this issue, AHRI commented that, 

due to the constant volume nature of the 

airflow in DDX–DOASes, the addition of 

defrost to DDX–DOASes presents 

challenges, and it is not in a position to 

present a proper solution at this time. 

AHRI also stated that it is aware of 

manufacturers that disable the heat 

pump operation in cold temperatures to 

avoid this issue. (AHRI, No. 11 at p. 13) 

The Joint Advocates, Goodman, and 

Carrier commented that defrost should 

be accounted for in the test procedure 

to provide a more representative 

measurement of field energy use. (Joint 

Advocates, No. 9 at p. 4; Goodman, No. 

14 at p. 2; Carrier, No. 6 at p. 4) Carrier 

added that DOE should use the T-test 26

defined in ANSI/AHRI 340/360 and 

ANSI/AHRI 210/240. (Carrier, No. 6 at 

p. 4) Goodman indicated that it will be 

very difficult to precisely capture 

defrost in the DDX–DOASes test 

procedure. (Goodman, No. 14 at p. 2) 

DOE understands that AHRI is 

referring to challenges in field operation 

defrosting for air-source heat pump 

DDX–DOASes. Preventing cold outdoor 

air from being brought into the supply 

air stream during a defrosting sequence 

(when the DDX–DOAS cannot operate 

as a heat pump) would require 

interruptions to the supply airflow, 

which is inconsistent with building 

code requirements to provide a 

continuous supply of ventilation air for 

most DDX–DOAS applications. DOE is 

aware of only a limited number of airsource heat pump DDX–DOAS units. 

DOE understands that these units may 

not continue heat pump operation 

during potential frosting conditions as a 

result of these challenges in field 

operation. Given these factors, DOE is 

not aware of test data (e.g., from T-tests) 

for such heat pumps during extended 

heating mode operation to understand 

better the level of frost accumulation 

and associated defrost energy 

expenditure. DOE also notes that AHRI 

920–2020 does not include any 

provisions for testing or calculating the 

defrost energy of DDX–DOAS air-source 

heat pumps. However, AHRI 920–2020 

arguably addresses this issue in another 

fashion, namely by providing in section 

5.5 that defrost control settings specified 

by the manufacturer in installation 

instructions may be set prior to heating 

mode tests in order to achieve steadystate conditions during the heating 

mode tests. As discussed in section 

III.B.3.d of this document, DOE is 

proposing to adopt the provisions of 

AHRI 920–2020 section 5.5, Defrost 

Controls for Air-Source Heat Pump 

during Heating Mode, as enumerated in 

section 2.2.1(b) of the proposed 

Appendix B. If these settings fail to 

prevent frost accumulation during the 

heating mode tests (resulting in 

unsteady conditions), then the 

manufacturer would need to seek a 

waiver from the test procedure to obtain 

an alternate method of test from DOE 

pursuant to 10 CFR 431.401. However, 

section 5.5 of AHRI 920–2020 also 

specifies that the Standard Rating 

Condition F heating mode test (which 

represents low temperature 

environmental conditions where 

frosting is likely) is optional to conduct, 

and if the Standard Rating Condition F 

test is not conducted, a default COP of 

1.0 (corresponding to electric resistance 

heating) is assigned at this rating point 

instead. Therefore, the manufacturer 

may choose to not conduct a test at 

Standard Rating Condition F instead of 

seeking a waiver. DOE has tentatively 

concluded that the test method set forth 

in section 5.5 of AHRI 920–2020 for 

defrost controls for air-source heat 

pump DDX–DOASes during heating 

mode offers a reasonable and workable 

approach, so the Department proposes 

to adopt such approach into the Federal 

test procedure. 

Due to the lack of sufficient 

information on how air-source heat 

pump DDX–DOAS units operate under 

frosting conditions, DOE is not 

proposing to include any provisions for 

including the defrost energy of DDX– 

DOAS air-source heat pumps. 

g. General Control Setting Requirements 

Requirements for adjustment of unit 

controls during set-up for testing of a 

DDX–DOAS are addressed in specific 

sections of AHRI 920–2020. Some 

examples include the following. Section 

5.2, ‘‘Equipment Installation,’’ requires 

that units be installed per 

manufacturer’s installation instructions 

(MII). Section 5.4.3, ‘‘Deactivation of 

VERS,’’ indicates that operation of the 

VERS may be deactivated for Standard 

Rating Conditions C or D if the VERS is 

capable of being deactivated. Section 

5.5, ‘‘Defrost Controls for Air-Source 

Heat Pump during Heating Mode,’’ 

provides instructions for setting of 

defrost controls. 

However, DOE notes that the test 

standard provides no general 

requirements indicating whether control 

settings can be adjusted as the test 

transitions through the four Standard 

Rating Conditions used for testing. 

Manual readjustment of control settings 

would not generally occur in field 

operation of DDX–DOASes as outdoor 

air conditions change (i.e., in the field, 

controls are configured at the time of 

installation and would not be actively 

adjusted on an ongoing basis in 

response to changes in outdoor 

temperature or humidity). Hence, to 

further ensure the representativeness of 

the test procedure, DOE is proposing 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36037 

27 ‘‘STI’’ is defined in AHRI 920–2020 as 

additional instructions provide by the manufacturer 

and certified to the U.S. DOE. As explained in 

section III.C.1 of this document, this NOPR does not 

propose certification requirements for DDX– 

DOAS—such requirements will instead be proposed 

in a separate Energy Conservation Standard 

rulemaking. Consistent with certification provisions 

for other commercial packaged air-conditioning and 

heating equipment, manufacturers include STI as 

part of the certification (see 10 CFR 429.43(b)(4)). 

DOE is proposing that manufacturers must adhere 

to the provisions of this test procedure starting on 

the compliance date for the related energy 

conservation standard rulemaking. Hence, this 

approach does not require that STI exist earlier than 

the date it must be certified to DOE. 

28The Option 1 test method includes additional 

specificity to the test room configuration for testing 

DDX–DOAS with energy recovery by allowing use 

of the three-chamber approach in addition to the 

example configuration provided in the current 

industry consensus test standard, in which the 

outdoor room is conditioned to both the required 

outdoor dry-bulb and humidity conditions. 

29AHRI’s directory of certified product 

performance for air-to-air energy recovery 

ventilators can be found at www.ahridirectory.org/ 

ahridirectory/pages/erv/defaultSearch.aspx. 

30As discussed in section III.B.4.g.i of this NOPR, 

DDX–DOASes with energy recovery wheel VERS 

may experience air transfer and leakage from the 

outdoor air path to the exhaust air (outdoor air 

transfer and leakage) and return air to the supply 

air (return air transfer and leakage). 

inclusion of a general requirement that 

control settings remain fixed and that 

there be no further manual adjustment 

thereof, once set initially for the first of 

the Standard Rating Conditions 

(Standard Rating Condition A). Absent 

such instruction, the controls could be 

adjusted as the test transitions through 

the four Standard Rating Conditions 

used for testing, which as discussed, 

would not be representative of the 

operation of the unit in the field. As 

such, DOE has initially determined, 

supported by clear and convincing 

evidence, that absent instruction for the 

control settings to be fixed during 

testing, the industry test procedure 

would not meet the statutory 

requirements of 42 U.S.C. 6314(a)(2)–(3) 

and is, therefore, proposing such 

instruction. 

Notwithstanding this proposal, DOE 

recognizes that some manual 

intervention, as permitted by AHRI 920– 

2020, and as specified in supplemental 

test instructions (STI),27 may be 

necessary as the test transitions through 

Standard Rating Conditions. However, 

such manual interventions are only 

permitted in limited and specific 

instances as identified in the test 

standard or STI. An example of such an 

allowed intervention is the use of the 

manual setting of compressor capacity 

staging for tests using the ‘‘Weighted 

average method,’’ as described in 

section 6.9.1 of AHRI 920–2020. In field 

operation, a DDX–DOAS set per the 

manufacturer’s installation instructions 

would attempt to achieve the target 

supply air dew point over the average of 

a time period with cycling (unsteady) 

operation between two compressor 

stages; to address this, the test standard 

calls for manual intervention, using two 

steady-state tests, one using each stage, 

and calculating a weighted average of 

the results. (This provision is discussed 

in depth in section III.B.3.d.v of this 

NOPR.) 

Thus, DOE is proposing to require 

that all control settings are to remain 

unchanged for all Standard Rating 

Conditions once system set-up has been 

completed, and component operation 

shall be controlled by the unit under 

test once the provisions in section 6 of 

AHRI 920–2020 (Rating Requirements) 

are met, except as specifically allowed 

by the test standard or STI (see section 

2.2.1(b)(i) of the proposed Appendix B). 

Issue–7: DOE requests comment on 

the proposed general control setting 

requirement for DDX–DOASes. 

h. Ventilation Energy Recovery Systems 

As discussed in section III.A.1 of this 

NOPR, the industry definition of ‘‘DXDedicated Outdoor Air System Units’’ is 

inclusive of units that provide preconditioning of outdoor air by direct or 

indirect transfer with return/exhaust air 

using an enthalpy wheel, sensible 

wheel, desiccant wheel, plate heat 

exchanger, heat pipes, or other heat or 

mass transfer apparatus. These preconditioning features are broadly 

referred to as ventilation energy 

recovery systems (‘‘VERS’’, or ‘‘energy 

recovery’’). ASHRAE Standard 90.1– 

2016 defines separate equipment classes 

and efficiency levels for DDX–DOASes 

with VERS. 

Section 5.4 of AHRI 920–2020 

specifies testing requirements for DDX– 

DOASes equipped with VERS. Section 

5.4.1 of AHRI 920–2020 specifies that 

units equipped with VERS can be tested 

using either one of two options: ‘‘Option 

1’’ or ‘‘Option 2’’. Option 1 requires 

operating the DDX–DOAS unit with 

VERS as it would operate in the field, 

maintaining the appropriate return air 

and outdoor air conditions for airflows 

entering the unit, and operating the 

VERS to provide energy recovery during 

the test (see section 5.4.1.1 of AHRI 

920–2020).28 In addition to specifying 

the outdoor air dry-bulb temperature 

and humidity conditions, Table 4 and 

Table 5 of AHRI 920–2020 specify 

return air inlet conditions that are 

applicable to DDX–DOASes with VERS. 

Section C2.4 in Appendix C of AHRI 

920–2020 also specifies that the return 

air be ducted into the unit from a 

separate test room maintaining the 

required return air inlet conditions. 

Option 2 involves setting the 

conditions of the air entering the unit so 

as to simulate the conditions that would 

be provided by the VERS in operation 

(see section 5.4.1.2 of AHRI 920–2020). 

Option 2 uses energy recovery device 

performance ratings based on ANSI/ 

AHRI 1060–2018 to calculate the air 

dry-bulb temperature and humidity 

conditions that would be provided by 

the energy recovery device. ANSI/AHRI 

1060–2018 references ANSI/ASHRAE 

84–2013, ‘‘Method of Testing Air-to-Air 

Heat/Energy Exchangers,’’ (ANSI/ 

ASHRAE 84–2013) (approved by 

ASHRAE on January 26, 2013) for 

conducting the test. These industry test 

standards provide a method for rating 

the performance of VERS in terms of 

sensible and latent effectiveness. DOE 

also notes that the performance ratings 

for energy recovery devices certified 

using ANSI/AHRI 1060–2018 are listed 

in AHRI’s directory of certified product 

performance.29

The operating conditions specified in 

ANSI/AHRI 1060–2018 may be different 

than the operating conditions specified 

for testing DDX–DOAS (i.e., airflow rate, 

which subsequently affects factors such 

as transfer/leakage airflow 30). Hence, 

section C4 of AHRI 920–2020 provides 

methods to adjust, for the DDX–DOAS 

operating conditions, the effectiveness 

values for sensible and latent transfer 

measured using ANSI/AHRI 1060–2018. 

Section C4 of AHRI 920–2020 also 

provides default values for sensible 

effectiveness and latent effectiveness. 

These can be used in cases where 

performance rating information based 

on ANSI/AHRI 1060–2018 is not 

available for a VERS, or the rotational 

speed for an energy recovery wheel has 

been changed from the speed used to 

determine performance ratings using 

ANSI/AHRI 1060–2018. 

The Option 2 approach would reduce 

test burden for most test laboratories by 

reducing the number of test rooms 

required as compared to conducting 

tests using Option 1. Because the 

outdoor ventilation air and return air 

would be maintained at the same 

conditions, there would be no transfer 

of heat or moisture in the VERS, nor any 

change of VERS-outlet supply air 

conditions associated with transfer or 

leakage of return air to the supply air 

plenum. In addition, testing using 

Option 2 is conducted with all 

components operating (e.g., with an 

energy recovery wheel rotating, or with 

the pump of a glycol-water runaround 

loop activated), such that all 

measurements would be representative 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36038 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

31See section 6.1.1.2 and Figure 2 of ANSI/ 

ASHRAE 198–2013. 

of the pressure drops and power 

consumption associated with the VERS. 

This approach avoids separate testing to 

measure power input of auxiliary 

components or of the exhaust air fan. 

Option 2 is applicable for DDX– 

DOASes for which a VERS provides the 

initial outdoor ventilation air treatment. 

DDX–DOAS units with VERS that 

provide conditioning downstream of the 

conditioning coil could not be tested 

using Option 2, since this option 

addresses VERS pre-conditioning only 

upstream of the conditioning coil. Such 

units would need to be tested using 

Option 1. 

In response to the July 2017 ASHRAE 

TP RFI, AHRI commented that testing of 

DDX–DOAS units with VERS would 

generally require a facility with three 

adjacent test chambers, which is not 

available in the known stock of existing 

laboratory spaces. (AHRI, No. 11 at p. 

14) AHRI stated that the test facility 

arrangement for testing of DDX–DOASes 

with energy recovery presented in 

ANSI/ASHRAE 198–2013,31 as 

referenced by AHRI 920–2020, is not 

adequate because laboratories cannot 

maintain both the required dry-bulb 

temperature and high humidity 

conditions in the outdoor room, since 

removing the high condenser heat load 

using a conventional conditioning 

system also excessively dehumidifies 

the chamber. The commenter also 

argued that capacity and stratification 

are significant issues with the existing 

test arrangement. AHRI surmised that a 

separate, third test room to provide 

conditioned outdoor air for the entering 

air to the energy recovery device would 

be required to provide adequate stability 

for testing. AHRI further asserted that 

because it is not feasible to adequately 

test units with VERS, DOE should limit 

the scope of the Federal test procedure 

at this time to DDX–DOAS units 

without VERS. (AHRI, No. 11 at p. 15) 

Based on DOE’s review of the test 

requirements and equipment available 

on the market, DOE is aware of test 

facilities capable of testing using Option 

1 for smaller DDX–DOAS units. Test 

facilities with similar configurations 

used for testing variable refrigerant flow 

multi-split air-conditioning and heat 

pump equipment would be large enough 

and equipped with enough controlled 

test rooms to meet the DDX–DOAS test 

procedure requirements. DDX–DOAS 

units with physical dimensions under 

10 feet by 10 feet (typically less than 

100 lbs. per hour MRC at Standard 

Rating Condition A), which represent 

more than 50 percent of equipment 

models available on the market, could 

be tested in these existing test facilities. 

Option 2 allows existing test facilities 

to test all DDX–DOAS units, including 

units larger than those that can be tested 

using Option 1. As discussed, Option 2 

requires neither a separate third test 

room to condition the outdoor 

ventilation air to the required 

temperature and humidity conditions, 

nor that the outdoor room in which the 

unit is located be conditioned to both 

the required dry-bulb and humidity 

conditions, because it does not require 

use of an air stream at outdoor air 

conditions. Aside from the chamber in 

which the test unit is installed, it 

requires only a second chamber at the 

simulated conditions. The inclusion of 

Option 2 in AHRI 920–2020 reduces 

testing burden compared to the ANSI/ 

AHRI 920–2015, which only provides 

test set-up and provisions that are 

mostly equivalent to the Option 1 

method in AHRI 920–2020 discussed 

previously. For these reasons, DOE 

tentatively concludes that existing test 

facilities would be capable of using the 

proposed test procedure for testing 

DDX–DOASes both with and without 

VERS. 

DOE is required under EPCA to adopt 

a Federal test procedure that is 

consistent with the applicable test 

procedure specified in the amended 

ASHRAE Standard 90.1 unless DOE 

determines, supported by clear and 

convincing evidence, that to do so 

would result in a test procedure that is 

not designed to produce test results 

which reflect the energy efficiency of 

DDX–DOASes in a representative 

average-use cycle or would be unduly 

burdensome to conduct. (42 U.S.C. 

6314(a)(4)(B); 42 U.S.C. 6314(a)(2) and 

(3)) In this NOPR, DOE is proposing to 

adopt the two options (i.e., Option 1 and 

Option 2) for testing DDX–DOASes with 

energy recovery, as provided in section 

5.4.1 of AHRI 920–2020 (as enumerated 

in section 2.2.1(b) of the proposed 

Appendix B). As discussed further in 

section III.B.3.a of this NOPR, DOE is 

proposing to define a ‘‘ventilation 

energy recovery system’’ as a feature 

that provides pre-conditioning of 

outdoor ventilation air entering the 

equipment through direct or indirect 

thermal and/or moisture exchange with 

the exhaust air leaving the unit. 

In addition, DOE notes that the 

relevant industry test standards (AHRI 

920–2020 and ASHRAE 198–2013) in 

some cases use synonymous but 

different terms to denote VERS. DOE 

proposes to include a section 2.3(b) in 

its proposed Appendix B indicating that 

the different synonymous terms all refer 

to VERS as defined in 10 CFR 431.92. 

The following subsections address 

specific aspects of the proposed test 

procedure pertaining to DDX–DOASes 

with VERS. 

i. Exhaust Air Transfer and Leakage 

DOE is aware that DDX–DOASes with 

energy recovery wheel VERS may 

experience air transfer and leakage from 

the outdoor air path to the exhaust air 

(outdoor air transfer and leakage) and 

return air to the supply air (return air 

transfer and leakage). Some of this air is 

leakage past the diametral seals that 

separate the outdoor and exhaust 

plenums on one side of the wheel and 

the return and supply plenums on the 

other side. Additional leakage from 

outdoor to exhaust or return to supply 

could be due to loose cabinet 

construction of the DDX–DOAS itself. 

Depending on the geometry of the 

energy recovery wheel media (e.g., 

whether the sheets of media making up 

the energy recovery wheel core are 

oriented parallel to this leakage flow 

direction), the air may pass through a 

portion of the media near the diametral 

seal. In addition, as a portion of the 

wheel passes from one side of the seal 

to the other, the air within that portion 

reverses direction—this represents 

either return air transferred to the 

supply side or outdoor air transferred to 

the exhaust side. The exhaust air 

transfer ratio (EATR) is defined in 

section 3.8 of AHRI 920–2020 as the 

fraction of airflow leaving the VERS that 

transfers or leaks from the return air 

inlet rather than passing through the 

VERS from the outdoor air inlet. 

The return air that transfers and leaks 

to the supply air side of an energy 

recovery wheel did not enter the DDX– 

DOAS as outdoor ventilation air. 

Therefore, the amount of fresh outdoor 

air delivered by the DDX–DOAS is less 

than the supply airflow and is equal to 

the supply airflow multiplied by the 

factor (1–EATR). In addition, the return 

air is already at neutral space 

conditions. Hence, the energy recovery 

wheel does not provide any meaningful 

conditioning for this air. When 

calculating MRC for a DDX–DOAS with 

an energy recovery wheel, section 10.5 

of ANSI/ASHRAE 198–2013 indicates 

that the calculation is based on the full 

supply airflow. DOE notes that any 

transfer or leakage air would increase 

the apparent dehumidification provided 

by the DDX–DOAS unit, since this air is 

already at space-neutral conditions— 

thus, a high EATR would boost the 

efficiency rating without providing any 

real benefit (for VERS other than energy 

recovery wheels, the EATR is 

considered to be equal to 0, under the 

assumption that cabinet air leakage 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36039 

32A purge mechanism cleans the portion of the 

wheel that has had contact with return air before 

it is used to precondition outdoor air. The cleaning 

is provided by outdoor air that passes through this 

portion of the wheel and is diverted into the return 

plenum to be discharged through the exhaust 

blower. Most purge mechanisms allow adjustment 

of the angle of the wheel sector that is subject to 

this cleaning function. At zero purge angle, there is 

no purge cleaning provided. 

through the VERS is negligible, so this 

issue would not affect these other 

VERS). ANSI/AHRI 920–2015 includes 

tracer gas tests for measuring EATR in 

its standard rating requirements (see 

section 5.1). As part of the July 2017 

ASHRAE TP RFI, DOE raised this issue, 

while recognizing that such leakage may 

be low enough in most energy recovery 

wheels that the EATR measurement 

could represent an unnecessary addition 

to test burden. 82 FR 34427, 34437 (July 

25 2017). DOE requested comment on 

whether EATR should be included in 

the test procedure for DDX–DOASes 

and, if so, how it should be used in 

determining DX–DOAS ratings. Id. 

In response to the RFI, on this issue, 

AHRI commented that the intent of the 

DOE test procedure for DDX–DOASes 

should not be to quantify energy 

recovery performance. AHRI pointed 

out that the AHRI certification directory 

publishes EATR values based on AHRI 

1060. (AHRI, No. 11 at p. 15) In 

addition, AHRI argued that test 

laboratories of sufficient size for testing 

DDX–DOASes are not currently 

equipped with tracer gas test 

equipment, as specified in ANSI/ 

ASHRAE 84–2013. (AHRI, No. 11 at p. 

14) No other comments were received 

on this issue. 

Since the July 2017 ASHRAE TP RFI, 

further refinements were made to the 

industry consensus test standard which 

have bearing on this matter. 

Specifically, sections 6 and C4 of AHRI 

920–2020 were revised to include 

methods to estimate EATR without 

requiring a tracer gas measurement, and 

to account for EATR’s impact on DDX– 

DOAS performance, using calculations 

tailored for testing under either Option 

1 or Option 2. These include using an 

EATR value that is based on testing in 

accordance with ANSI/AHRI 1060–2018 

with zero purge angle,32 zero return-tosupply pressure differential, and 100- 

percent of nominal energy recovery 

wheel supply airflow, and adjusting the 

EATR value for the DDX–DOAS supply 

airflow rate based on an assumption that 

the leakage/transfer flow is not affected 

by the supply and return air flow rates. 

The adjusted value of EATR is then 

used in the calculation of DDX–DOAS 

performance. Specifically, the MRC 

calculations in section 6.9 of AHRI 920– 

2020 take into account the conditioning 

of the air that leaked or transferred from 

the return plenum to the supply plenum 

(equal to adjusted EATR multiplied by 

supply airflow) only from return 

conditions to supply conditions to 

reflect the fact that this air did not enter 

the DDX–DOAS unit at outdoor air 

conditions. In cases where EATR rating 

information based on ANSI/AHRI 1060– 

2018 is not available, or if, for an energy 

recovery wheel, the rotational speed has 

been changed from the speed used to 

determine performance ratings using 

ANSI/AHRI 1060–2018, sections 6.5 and 

C4 of AHRI 920–2020 provide a default 

value of EATR that would be used to 

rate the DDX–DOAS. 

DOE has tentatively determined that 

the use of default or certified values for 

EATR in AHRI 920–2020 (instead of 

tracer gas tests) has addressed AHRI’s 

comments on quantifying energy 

recovery performance. Accordingly, 

DOE is proposing to adopt these 

changes made by AHRI 920–2020 

(section 6.5 Determination of EATR), as 

enumerated in section 2.2.1(c) of the 

proposed Appendix B; and Appendix C 

of AHRI 920–2020 (which includes 

section C4 Simulated Ventilation Air 

Conditions for Testing Under Option 2), 

as enumerated in section 2.2.1(f) of the 

proposed Appendix B). 

ii. Purge Angle Setting 

Section 6.6 of ANSI/ASHRAE 198– 

2013 requires that for any DDX–DOAS 

equipped with an energy recovery 

wheel, the purge angle of such feature 

must be set to zero when testing the 

DDX–DOAS unit. As part of the July 

2017 ASHRAE TP RFI, DOE requested 

comment on whether all purge devices 

are adjustable to zero purge and whether 

it is always clear how to set them to zero 

purge. 82 FR 34427, 34439 (July 25, 

2017). DOE also requested comment on 

whether it is appropriate to set purge to 

zero or whether it would be more 

appropriate to set purge to its highest 

setting or to some other standard setting. 

Id. 

None of the comments on the RFI 

indicated that there are purge devices 

that are not adjustable to zero angle, nor 

that it is unclear how to adjust purge 

angle to zero. Carrier commented that 

for the short period of time required for 

a performance test, it should not be a 

problem to set the purge angle to zero. 

(Carrier, No. 6 at p. 8) As discussed 

previously, AHRI stated that there are 

no independent laboratories capable of 

testing DDX–DOAS units with VERS. As 

a result, AHRI argued that this issue 

does not need to be addressed at this 

time. However, AHRI stated, if in the 

future laboratories are able to test DDX– 

DOASes equipped with VERS, then 

manufacturers should be allowed to 

specify the purge setting for testing, as 

is done in AHRI 1060. (AHRI, No. 11 at 

p. 20) 

DOE has tentatively concluded that a 

zero purge angle aligns with the 

selection that manufacturers would 

generally make (i.e., a zero purge angle), 

because non-zero purge prevents the 

purge portion of the wheel from 

contributing to energy recovery 

effectiveness (since outdoor ventilation 

air passing through it is ejected out of 

the unit to the exhaust rather than 

becoming part of the supply airflow). 

Also, the purge section restricts the flow 

area for the remaining outdoor air that 

becomes supply air, thus increasing 

pressure drop and fan power. For these 

reasons, energy recovery wheel 

performance (and likewise DDX–DOAS 

performance and efficiency) will be 

reduced when operating with a non-zero 

purge angle. Furthermore, basing DDX– 

DOAS performance ratings on a zero 

purge angle provides greater consistency 

in testing. DOE notes that section C4.1 

of AHRI 920–2020—the industry 

consensus test standard—includes a 

requirement for testing DDX–DOAS 

units using zero purge angle, whether 

testing using Option 1 or Option 2 

(through inclusion of EATR0, which is 

defined in section 11 of AHRI 920–2020 

as being determined using zero purge 

angle). For these reasons, DOE is 

proposing to adopt the requirement in 

AHRI 920–2020 to use a zero purge 

angle for testing DDX–DOAS with 

energy recovery wheels (section C4.1 of 

Appendix C of AHRI 920–2020), as 

enumerated in section 2.2.1(f) of the 

proposed Appendix B. 

iii. Return Air External Static Pressure 

Requirements 

ANSI/ASHRAE 198–2013 specifies 

testing DDX–DOASes with VERS with 

return air passing into the unit and 

exiting at the exhaust air connection. 

DOE noted in the July 2017 ASHRAE TP 

RFI that ANSI/AHRI 920–2015 does not 

address setting the external static 

pressure (ESP) for the return airflow. 82 

FR 34427, 34437 (July 25, 2017). DDX– 

DOAS units are typically installed and 

operated in the field with return air 

ducting. Therefore, when in operation, 

the return air fans consume additional 

energy to overcome the static pressure 

imposed by the return air ducts. As part 

of the July 2017 ASHRAE TP RFI, DOE 

requested comment on the ESP levels 

that should be used for return airflow. 

Id. 

In response, AHRI stated that Table 4 

of ANSI/AHRI 920–2015 was intended 

to represent ESP of both supply and 

return airflow. AHRI also stated that 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36040 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

revisions to ANSI/AHRI 920–2015 will 

refer to the same table for return airflow 

ESP. (AHRI, No. 11 at p. 15) DOE 

received no other comments on this 

issue. 

Consistent with the AHRI comment, 

section 6.1.5.6 of AHRI 920–2020 does 

include different ESP requirements for 

supply and return airflow, thereby 

resolving the identified issue. 

Accordingly, DOE is proposing to adopt 

the ESP requirements set forth in AHRI 

920–2020 (section 6.1.5 Supply and 

Return Airflow Rates), as enumerated in 

section 2.2.1(c) of the proposed 

Appendix B). 

iv. Target Return Airflow Rate 

In the July 2017 ASHRAE TP RFI, 

DOE noted that for testing DDX–DOAS 

units equipped with VERS, Tables 2 and 

3 in ANSI/AHRI 920–2015 provide 

return airflow temperature conditions 

and indicate that the temperature 

conditions apply to units with energy 

recovery at balanced airflow. 82 FR 

34427, 34437 (July 25, 2017). It is 

unclear from ANSI/AHRI 920–2015 

what airflow streams should be 

balanced, how to determine if they are 

balanced, and within what tolerances 

they should be balanced. In the July 

2017 ASHRAE TP RFI, DOE requested 

comments on which airflow streams 

should be balanced and whether 

balanced airflow is representative of 

field use. Id. 

On this topic, AHRI raised a number 

of issues with testing DDX–DOAS 

equipped with VERS generally, as 

previously discussed. AHRI also stated 

that using balanced airflows is 

consistent with the test procedure for 

rating VERS described in ANSI/AHRI 

1060–2018. AHRI further commented 

that in field operation, unbalanced 

flows may be needed to maintain 

positive building pressure; however, 

most equipment selection is done at or 

near balanced airflows. (AHRI, No. 11 at 

pp. 14–15) 

Subsequent updates to the industry 

consensus test standard at AHRI 920– 

2020 shed further light on this issue. 

Specifically, section 6.1.5 of AHRI 920– 

2020 specifies the return airflow rate 

must be within 3 percent of the 

measured supply airflow rate. Based on 

DOE’s review of DDX–DOAS product 

literature and consideration of the AHRI 

comment, it has become apparent that 

there is no clear optimal ratio of supply 

airflow to return airflow for DDX–DOAS 

testing to be representative of field use. 

Therefore, DOE has tentatively 

concluded that the provision in AHRI 

920–2020 is appropriate. 

i. Demand-Controlled Ventilation 

DDX–DOAS units are often used in 

demand-controlled ventilation (DCV) 

operation, which regulates the building 

ventilation requirement based on 

parameters such as building occupancy. 

Typically, a DCV system monitors the 

concentration of carbon dioxide (CO2) in 

the return air or in the building and 

regulates the supply airflow rate 

accordingly. During periods of nonoccupancy, which could represent a 

significant portion of field-use, the DCV 

system controls the unit to operate at a 

low airflow rate, thereby reducing the 

unit’s overall energy use. DDX–DOASes 

using DCV systems are typically 

equipped with variable-speed supply 

fans that can be adjusted to meet 

changing ventilation needs. In the July 

2017 ASHRAE TP RFI, DOE sought 

comments on whether to include 

operation under DCV conditions (i.e., 

low supply airflow conditions) to be 

included as part of DOE’s test 

procedure. 82 FR 34427, 34437 (July 25, 

2017). 

In response to this issue, the Joint 

Advocates encouraged DOE to adopt an 

efficiency metric that captures the 

benefits of DCV. The Joint Advocates 

stated that adopting such a metric could 

provide more field-representative 

equipment ratings and better inform 

consumers when purchasing equipment. 

Further, the Joint Advocates argued that 

capturing the benefits of DCV would 

promote adoption of variable speed 

fans, provide more flexibility in 

building operation, and reduce energy 

use. (Joint Advocates, No. 9 at p. 2, 4) 

AHRI and Carrier commented that the 

performance of the DX–DOAS under 

DCV operation must be characterized 

prior to developing a test procedure and 

that adopting provisions to address DCV 

operation could significantly increase 

the cost and complexity of testing. AHRI 

further stated that DCV operation is 

primarily controlled by building 

operators. Carrier stated that 

performance would depend highly on 

the building type, occupancy, and site 

requirements for demand ventilation. 

(AHRI, No. 11 at p. 14; Carrier, No. 6 at 

p. 4) 

DOE reviewed the comments and 

considered whether to adopt testing 

conditions to account for the energy use 

profiles of models with low supply 

airflow rates that are typically 

experienced by units with DCV. 

Incorporation of the airflow modulation 

that would be enabled by DCV might 

provide more representative efficiency 

ratings, help in consumer decision 

making, and potentially promote the 

market penetration of variable speed 

fans. However, DOE is not aware of 

representative field data regarding the 

typical DDX–DOAS duty cycle when 

operating with DCV and, thus, agrees 

with the comments of AHRI and Carrier 

that characterization of DCV 

performance would be an important first 

step in integrating this control feature 

into the test procedure. DOE further 

agrees that adopting additional testing 

requirements to capture the effect of 

DCV could significantly increase testing 

cost and complexity, as noted in 

comments provided by AHRI and 

Carrier. Given the lack of data on infield performance and the anticipated 

additional testing burden of such a test, 

DOE has tentatively decided not to 

include performance under DCV 

operation in its proposed test procedure 

for DDX–DOASes at this time. 

j. Tolerances for Supply and Return 

Airflow and External Static Pressure 

DOE noted in the July 2017 ASHRAE 

TP RFI that Table 1 of ANSI/ASHRAE 

198–2013 includes operating and 

condition tolerances of 5 percent for 

airflow rate. 82 FR 34427, 34439 (July 

25, 2017). It includes a test operating 

tolerance for ESP equal to 0.05 in H2O 

and a test condition tolerance for ESP of 

0.02 in H2O. As provided in section 

5.2.2 of ANSI/AHRI 920–2015, the 

airflow rate and ESPs are set at Standard 

Rating Condition C dry-bulb 

temperatures without the refrigeration 

systems and energy recovery (if 

applicable) in operation. ANSI/AHRI 

920–2015 states in section 5.2.2.4 that 

once the airflow rate is set, the fan 

speeds shall not be adjusted for the 

remaining tests. DDX–DOAS units that 

are for use with air ducting are required 

by the industry test standard to be set 

up with ESP requirements in Table 4 of 

ANSI/AHRI 920–2015, and units tested 

as if they would be installed without 

ducts are tested with 0 in H2O ESP. 

DOE notes that while operating in 

dehumidification mode, the airflow 

rates and ESPs may fluctuate more than 

for ‘‘dry’’ operation as condensate 

accumulates and then drains from the 

cooling coil. In addition, for 

dehumidification and heating tests, the 

density of supply air may be different, 

which may change fan performance, 

and, thus, the ESP. These factors could 

cause the supply air ESP to fluctuate 

more than the operating tolerances 

specified in Table 1 of ANSI/ASHRAE 

198–2013, and/or to deviate from the 

specified ESP by more than the test 

condition tolerance. Likewise, the 

airflow rates could fluctuate more than 

the specified operating tolerances, and 

the average airflows could deviate by 

more than the test condition tolerances 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36041 

from their target values. If this occurs, 

it is not clear how manufacturers would 

correct the issue without being able to 

adjust the fan speed and ESP, since such 

action is precluded by section 5.2.2.4 of 

ANSI/AHRI 920–2015. 

In the July 2017 ASHRAE TP RFI, 

DOE noted that the 5-percent condition 

tolerance on airflow rate is less stringent 

than the 3-percent condition tolerance 

adopted in DOE’s test procedure for 

more typical commercial package air 

equipment. 82 FR 344271, 34439 (July 

25, 2017). On August 6, 2015, DOE 

published a test procedure NOPR that 

proposed to apply a ±5-percent 

condition tolerance on cooling full-load 

indoor airflow rate for more typical 

commercial package air conditioning 

equipment. 80 FR 46870, 46873. In 

response to the proposed tolerance for 

more typical commercial package air 

conditioning equipment, DOE received 

several comments suggesting that a 5- 

percent tolerance would result in too 

much variation in the measurement of 

energy efficiency ratio and cooling 

capacity. After considering stakeholder 

comments, DOE adopted a 3-percent 

tolerance in a final rule published on 

December 23, 2015. 80 FR 79655, 

79659–79660. As part of the July 2017 

ASHRAE TP RFI, DOE expressed 

concern that that the 5-percent 

condition tolerance on airflow in ANSI/ 

ASHRAE 198–2013 may result in too 

much test variability for DDX–DOASes 

and requested comment on whether this 

airflow tolerance is acceptable. 82 FR 

34427, 34439 (July 25, 2017). 

AHRI commented in response to the 

July 2017 ASHRAE TP RFI that 

manufacturers who have performed 

testing have stated that meeting the 

tolerances specified in ANSI/AHRI 920– 

2015 and ASHRAE 198–2013 is not 

feasible due to how the testing is 

performed. Once the refrigeration 

system is engaged for determining 

ISMRE and ISCOP ratings, changes in 

moisture present on the cooling coil and 

air density affect the standard airflow 

and associated ESP. AHRI 

recommended that the ±0.05 in H2O ESP 

tolerance and a 3-percent airflow 

tolerance be observed during the airflow 

and fan speed setting at Standard Rating 

Condition C without the refrigeration 

system operating. AHRI also stated that 

during the Standard Rating Condition 

tests, the DDX–DOAS fan speeds and 

airflow-measuring apparatus fan speeds 

shall not be adjusted, consistent with 

airflow setting and operation in the 

field. Nevertheless, AHRI stated that the 

average measured airflows should be 

required to be within 5 percent of the 

manufacturer’s rated standard airflow 

during all rating tests and that the 

average measured ESPs should be 

within 15 percent of the required ESP to 

indicate a valid test, but the commenter 

did not indicate whether the fans of the 

test unit or the airflow-measuring 

apparatus should be adjusted to 

maintain these tolerances. (AHRI, No. 

11 at p. 18) 

DOE notes that AHRI 920–2020 

revised the test condition and operating 

tolerances for airflow and ESP. Section 

6.1.5 of AHRI 920–2020 specifies 

airflow test condition tolerances of ±3 

percent of the manufacturer-provided 

airflow rate for all DDX–DOASes when 

setting the airflow, provided that this 

airflow rate meets the supply air dew 

point temperature requirement, as 

discussed in section III.B.4.d.i of this 

NOPR. For setting the return airflow 

rate, section 6.1.5 of AHRI 920–2020 

specifies the same test condition 

tolerances as for supply airflow rate, 

except that for return airflow rate, the 

target is equal to the measured supply 

airflow rate. This specification ensures 

that supply and return airflows remain 

balanced, as discussed in section 

III.B.3.h.iv of this NOPR. These test 

condition tolerances for airflow and ESP 

are only required when setting the 

airflow. Once the airflow rate is set, the 

dehumidification and heating tests are 

then conducted without further 

adjustments to the supply fan, return 

fan, or airflow measuring apparatus. 

Section 6.1.5 and Table 9 of AHRI 920– 

2020 indicate that the supply and return 

airflow and ESP condition tolerances 

are not required to be maintained during 

the dehumidification and heating tests. 

While these provisions are contrary to 

AHRI’s recommendation in response to 

the July 2017 ASHRAE TP RFI to 

impose a 5-percent airflow condition 

tolerance and a 15-percent ESP 

condition tolerance during 

dehumidification and heating tests, DOE 

believes these changes in AHRI 920– 

2020 address AHRI’s concerns about 

testing problems associated with the 

tolerances in ANSI/AHRI 920–2015 and 

ASHRAE 198–2013. 

AHRI 920–2020 additionally includes 

a list of test operating tolerances, 

including those for external static 

pressure and airflow nozzle differential 

pressure. AHRI 920–2020 does not 

include changes to the test operating 

tolerance for ESP (0.05 in H2O total 

observed range, specified in Table 9 of 

AHRI 920–2020). Whereas ANSI/ 

ASHRAE 198–2013 provides a 5-percent 

operating tolerance directly on the 

airflow rate, Table 9 of AHRI 920–2020 

provides a 5-percent operating tolerance 

for airflow rate in the form of airflow 

nozzle differential pressure. DOE has 

initially determined that the airflow 

operating tolerance approach in AHRI 

920–2020 is preferable because the 

airflow nozzle differential pressure 

provides a more direct indication of the 

airflow variation, since airflow is 

calculated based on this value. 

Additionally, other industry test 

standards such as ANSI/ASHRAE 37– 

2009 include an operating tolerance on 

the nozzle pressure drop rather than 

directly on airflow. DOE believes that 

these operating tolerances, in addition 

to the condition tolerances for setting 

airflow, would maintain repeatable and 

reproducible results while ensuring that 

testing is representative of field use. 

Accordingly, DOE is proposing to adopt 

the test condition and operating 

tolerances for airflow and ESP specified 

in AHRI 920–2020 (section 6.1.5 Supply 

and Return Airflow Rates and section 

6.6.2 Test Measurement Tolerances, 

which contains Table 9), as enumerated 

in section 2.2.1(c) of the proposed 

Appendix B). 

k. Secondary Dehumidification and 

Heating Capacity Tests 

Commercial package air-conditioners 

and heat pumps with cooling capacity 

less than 135,000 Btu/h are required to 

undergo a secondary test to verify the 

cooling or heating capacity and energy 

efficiency results (see, e.g., ANSI/ 

ASHRAE 37–2009 section 7.2.1, which 

is referenced by appendix A to subpart 

F of 10 CFR part 431). Neither ANSI/ 

AHRI 920–2015 nor ANSI/ASHRAE 

198–2013 specify a secondary test 

method for verifying the 

dehumidification and heating capacity 

of DDX–DOAS, but section 6.7 of AHRI 

920–2020 does specify secondary tests. 

The measurement of dehumidification 

and heating performance of DDX– 

DOASes is based on measurements of 

airflow rate, temperature, and humidity, 

which have uncertainties associated 

with them. Thus, a secondary test 

method may be essential to confirm the 

accuracy of the primary test method. 

As part of the July 2017 ASHRAE TP 

RFI, DOE requested comment on the 

need for a secondary test method 

requirement for DDX–DOAS testing. 82 

FR 34427, 34439 (July 25, 2017). AHRI 

commented that condensate 

measurement would be appropriate as a 

secondary method, if energy recovery 

units are excluded from the test 

procedure. (AHRI, No. 11 at p. 19) 

Section C5.1 of AHRI 920–2020 

includes a condensate-based test 

method as a secondary measure of 

dehumidification capacity. The method 

measures the weight of the condensate 

(i.e., water vapor in the outdoor 

ventilation air that condenses on the 

conditioning coil and is removed from 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36042 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

the air) collected during the 

dehumidification test and uses it to 

calculate a secondary measure of MRC. 

This secondary measure of MRC is then 

compared to the primary MRC 

measurement, which is based on supply 

and outdoor ventilation airflow and air 

condition measurements. 

AHRI 920–2020 requires this 

secondary measure of MRC for all 

dehumidification tests, and comparison 

to the primary measure of MRC at 

Standard Rating Condition A. This 

requirement is for all DDX–DOAS units 

that: (a) Do not use condensate collected 

from the dehumidification coil to 

enhance condenser cooling or include a 

secondary dehumidification process for 

which the moisture removed from the 

supply air stream is not collectable in 

liquid form, and (b) either are not 

equipped with VERS or are equipped 

with VERS and tested using Option 2 

(see section C5.1 of AHRI 920–2020). 

AHRI 920–2020 does not require a 

secondary dehumidification capacity 

measurement for DDX–DOAS units 

equipped with VERS that are tested 

using Option 1. DOE understands that 

this is because: (a) No viable method has 

been developed and validated that 

appropriately accounts for the water 

vapor that transfers between air streams 

of an energy recovery wheel, and (b) the 

test burden of accounting for moisture 

in the exhaust air stream would be 

excessive. DOE is proposing to adopt 

the secondary capacity test 

measurements specified in AHRI 920– 

2020 (section C5.1 Dehumidification 

Capacity Verification), as enumerated in 

section 2.2.1(f) of the proposed 

Appendix B), including the cooling 

condensate secondary test measurement 

discussed previously. 

For DDX–DOAS units with energy 

recovery tested using Option 2, as 

discussed in section III.B.3.h of this 

NOPR, the test is conducted by setting 

the conditions of the air entering the 

unit (at both the outdoor air inlet and 

return air inlet) to simulate the 

conditions that would be provided by 

the energy recovery device in operation. 

As a result, the moisture removal (in 

dehumidification mode) or heating (in 

heating mode for heat pump DDX– 

DOAS) measured during the Option 2 

primary and secondary capacity tests 

reflects only the moisture removed or 

heating by the conditioning coil. The 

MRC or qhp for the DDX–DOAS is 

calculated by adjusting the measured 

moisture removal or heating for the 

primary test to account for the total 

moisture removal or heating by the 

energy recovery device and the 

conditioning coil. Because the moisture 

removal or heating capacity measured 

for the primary and secondary tests are 

based on the simulated test conditions, 

sections 6.9 and 6.10 of AHRI 920–2020 

use these measured values for the 

secondary capacity verification under 

Option 2. DOE is proposing to adopt 

these requirements specified in AHRI 

920–2020 (section 6.9 Moisture Removal 

Efficiency Ratings and section 6.10 

Heating Capacity), as enumerated in 

section 2.2.1(c) of the proposed 

Appendix B). 

a. Corrections 

In addition to substantive changes, 

AHRI 920–2020 also provides minor 

corrections to instructions in ANSI/ 

AHRI 920–2015. However, in its review 

of AHRI 920–2020, DOE identified an 

error and an omission in the latest 

industry test procedure. Specifically, 

DOE notes that section 6.9.2 of AHRI 

920–2020 provides erroneous 

instruction for the calculation of the 

degradation coefficient, and sections 

6.1.5.2.3 and 6.1.5.2.4 of AHRI 920– 

2020 refer to the term ‘‘non-standard 

low-static motor’’ without providing a 

definition or explanation of this term. 

DOE proposes to correct the calculation 

instruction and define the term ‘‘nonstandard low-static motor,’’ as discussed 

further in the following paragraphs. 

DOE also notes a correction made by 

AHRI 920–2020 to address an error in 

the calculation of supplementary heat 

penalty in ANSI/AHRI 920–2015. 

i. Calculation of the Degradation 

Coefficient 

As mentioned in section III.B.3.d.v of 

this NOPR, AHRI 920–2020 includes 

provisions for cases where the unit 

provides excess dehumidification or 

heating capacity when operating at its 

lowest-capacity compressor stage. A 

degradation coefficient is applied to the 

MRE and MRE70 when the supply air 

dew point temperature measured when 

operating the unit at its lowest-capacity 

compressor stage is lower than the target 

supply air dew point temperature in 

excess of the specified test condition 

tolerance. This degradation coefficient 

accounts for the re-evaporation of 

condensate which occurs during cycling 

operation (i.e., when the compressor 

cycles on and off to achieve the target 

supply air dew point temperature). DOE 

understands that the degradation is 

more pronounced for DDX–DOASes 

equipped with VERS for latent energy 

recovery (or total energy recovery), and, 

thus, the degradation coefficient should 

be greater for DDX–DOASes operating 

total energy recovery VERS. Equation 20 

in section 6.9.2 of AHRI 920–2020 

appears to incorrectly attribute the 

lower degradation coefficient to DDX– 

DOASes operating with VERS. As such, 

DOE has initially determined, supported 

by clear and convincing evidence, that 

absent a correction, the degradation 

coefficient as applied in AHRI 920–2020 

would not meet the statutory 

requirements of 42 U.S.C. 6314(a)(2)–(3) 

because it would not produce 

representative results. DOE proposes to 

correct Equation 20 by specifying that it 

is to be used for DDX–DOASes ‘‘without 

VERS, with deactivated VERS (see 

section 5.4.3 of AHRI 920–2020), or 

with sensible-only VERS tested under 

Standard Rating Conditions other than 

D’’ (emphasis added) because DDX– 

DOASes with total energy recovery 

VERS or with sensible-only VERS tested 

under Standard Rating Condition D are 

considered separately in Equation 21, 

which calculates a greater degradation 

coefficient. This correction would be 

implemented in section 2.2.1(c)(iii) of 

proposed Appendix B. 

ii. Non-Standard Low-Static Motor 

As mentioned in section III.B.3.d.i of 

this NOPR, section 6.1.5 of AHRI 920– 

2020 includes instructions for setting 

the supply airflow rate for testing. In 

particular, sections 6.1.5.2.1 through 

6.1.5.2.5 of AHRI 920–2020 provide 

directions for adjusting the fans should 

an initial attempt at setting the airflow 

be unsuccessful. 

Section 6.1.5.2.3 of AHRI 920–2020 

specifies that if a fan’s maximum speed 

is too low to satisfy the airflow and 

external static pressure requirements 

within tolerance (i.e., the motor speed is 

at the highest setting, a larger 

compatible off-the-shelf sheave is not 

available, or increased speed would 

overload the motor or motor drive) and 

the motor is not a ‘‘non-standard lowstatic motor,’’ the tests are to be 

conducted at the fan’s maximum speed 

with the external static pressure 

satisfying the requirements in Table 7. 

However, if the motor is a ‘‘nonstandard low-static motor,’’ section 

6.1.5.2.4 of AHRI 920–2020 specifies 

that the maximum available speed 

should be used but the supply and 

return airflow rates should satisfy 

aforementioned tolerance requirements 

(implying that the external static 

pressure requirements in Table 7 need 

not be met). AHRI 920–2020 does not 

define ‘‘non-standard low-static motor’’ 

in order to determine which of the two 

methods is appropriate. Without a 

definition of ‘‘non-standard low-static 

motor,’’ manufacturers may not apply 

the ‘‘maximum speed’’ provisions 

consistently, and the potential for 

variation risks results that do not reflect 

the equipment’s representative average 

energy efficiency or energy use. As 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36043 

such, DOE has initially determined, 

supported by clear and convincing 

evidence, that in the absence of a 

definition of ‘‘non-standard low-static 

motor,’’ the industry test procedure 

would not meet the statutory 

requirements of 42 U.S.C. 6314(a)(2)– 

(3). 

DOE understands that a non-standard 

low-static fan motor may be used for 

DDX–DOASes where the application 

requires less ductwork, which results in 

a lower external static pressure when 

operating at the same nominal supply or 

return airflow rate. This motor would be 

distributed in commerce as part of an 

individual model within the same basic 

model of DDX–DOAS that is also 

distributed in commerce with a motor 

that can meet the external static 

pressure required by AHRI 920–2020. A 

parallel situation occurs for Commercial 

and Industrial Unitary Air-conditioning 

and Heat Pump Equipment, for which 

section D3 in Appendix D of AHRI Test 

Standard 340/360–2019, ‘‘Performance 

Rating of Commercial and Industrial 

Unitary Air-conditioning and Heat 

Pump Equipment’’ (AHRI 340/360– 

2019) defines ‘‘non-standard motor’’ as 

an indoor fan motor that is not the 

standard indoor fan motor and that is 

distributed in commerce as part of an 

individual model within the same Basic 

Model. The same section D3 defines 

‘‘standard indoor fan motor’’ as the 

motor specified by the manufacturer for 

testing and shall be distributed in 

commerce as part of a particular model. 

In both cases, the non-standard motor 

has a horsepower level that is not 

compatible with the external static 

pressure rating condition—for DDX– 

DOAS, the issue arises when the nonstandard motor does not have sufficient 

power to deliver the required external 

static pressure. Therefore, in the 

proposed Appendix B in section 

2.2.1(a)(i), DOE is proposing to define 

‘‘non-standard low-static fan motor’’ as 

a supply fan motor that cannot maintain 

external static pressure as high as 

specified in Table 7 of AHRI 920–2020 

when operating at a manufacturerspecified airflow rate and that is 

distributed in commerce as part of an 

individual model within the same basic 

model of a DDX–DOAS that is 

distributed in commerce with a different 

motor specified for testing that can 

maintain the required external static 

pressure. 

Issue–8: DOE is requesting comment 

on the proposed definition of ‘‘nonstandard low-static fan motor’’ and 

whether the proposed definition reflects 

stakeholder understanding of the term. 

iii. Calculation of Supplementary Heat 

Penalty 

Section 6.1.3.1 of ANSI/AHRI 920– 

2015 includes a supplementary heat 

penalty for units that are unable to 

achieve the minimum supply air drybulb temperature of 70 °F while testing 

at each Standard Rating Condition 

specified in Table 2 and Table 3 of 

ANSI/AHRI 920–2015. The 

supplementary heat penalty calculates 

the difference in enthalpy from the 

delivered supply air and air at the 

minimum supply air temperature 

(70 °F). After reviewing the equations, 

DOE noted in the July 2017 ASHRAE TP 

RFI that the term for supply airflow rate 

is missing from the supplementary heat 

penalty equations. 82 FR 34427, 34436 

(July 25, 2017). 

In response to the July 2017 ASHRAE 

TP RFI, AHRI confirmed that the 

supplementary heat formula in ANSI/ 

AHRI 920–2015 is missing the airflow 

term, QSA, in section 6.1.3.1, and the 

organization committed to include such 

term in the next revision of the test 

standard. (AHRI, No. 11 at p. 11) DOE 

notes that this change has been included 

in AHRI 920–2020, thereby resolving 

the problem. Accordingly, DOE 

proposes to adopt the revised 

supplementary heat penalty equation 

contained in AHRI 920–2020 that 

includes the supply airflow rate term 

(section 6.1.3.1 Initial Standard Rating 

Condition A Dehumidification Test), as 

enumerated in section 2.2.1(c) of the 

proposed Appendix B). 

In the July 2017 ASHRAE TP RFI, 

DOE further noted that section 6.1.3.1 of 

ANSI/AHRI 920–2015 calls for a 

supplementary heat penalty if the 

supply air temperature is less than 

70 °F, but the incorporation of this 

penalty into the MRE and COP 

equations is not clearly described. DOE 

also noted that it is not clear whether 

the ANSI/ASHRAE 198–2013 test 

method considers this penalty. 82 FR 

34427, 34436–34437 (July 25, 2017). 

AHRI commented that the 

supplementary heat penalty should be 

added if the minimum 70 °F 

temperature is not met, and that this 

value is added to the measured power 

input, which is represented as PT in 

section 10.6 of ANSI/ASHRAE 198– 

2013. (AHRI, No. 11 at p. 11) DOE notes 

that this clarification is included in 

section 6.9 of AHRI 920–2020 in the 

calculation of MRE70, which 

incorporates the energy impact of 

heating the supply air to 70 °F. As 

discussed in section III.B.2 of this 

NOPR, DOE is proposing to adopt the 

ISMRE2 metric specified in section 6.13 

of AHRI 920–2020 that does not include 

the supplementary heat penalty as the 

regulated metric for DDX–DOAS, while 

the MRE70 (and ISMRE270) metric that 

incorporates the supplementary heat 

penalty may be used for representations. 

As a result, the supplementary heat 

penalty would only be added to the total 

power input for the calculation of the 

optional MRE70 ratings. 

With regards to the COP calculation, 

AHRI commented that the intent was 

that the supplementary heat penalty 

would be added to the numerator as 

additional heat capacity and the 

denominator as additional power 

consumed to calculate a COP indicative 

of running an electric heater to meet a 

supply air temperature of 70 °F. (AHRI, 

No. 11 at p. 13) DOE notes that this 

clarification was included in section 

6.11.2 of AHRI 920–2020 in the 

renamed COPISCOP metric, and 

accordingly, DOE is proposing to adopt 

the revised COPISCOP calculation 

(section 6.11.2 of AHRI 920–2020), as 

enumerated in section 2.2.1(c) of the 

proposed Appendix B). 

2. Determination of Represented Values 

a. Basic Model 

To determine the energy efficiency of 

a basic model, DOE’s certification 

requirements generally require 

manufacturers to test a sample of units 

of that basic model to represent its 

performance. (10 CFR 429.11) The basic 

model may include multiple individual 

models having similar performance 

features and characteristics. Typically, 

DOE provides a definition of a basic 

model for each type of covered 

equipment. In this NOPR, DOE proposes 

a definition for DDX–DOAS basic model 

derived from the basic model definition 

for other commercial packaged air 

conditioning and heating equipment set 

forth at 10 CFR 431.92. Specifically, 

DOE replaced the criterion to have 

common nominal cooling capacity with 

common nominal MRC. DOE is also 

proposing to include the common 

nominal MRC in the definition of a 

basic model for small, large and very 

large air-cooled or water-cooled 

commercial package air conditioning 

and heating equipment, which includes 

DDX–DOASes. The proposed definition 

of basic model of a DDX–DOAS also 

specifies that a basic model must 

include units with similar VERS 

equipment. DOE is proposing in this 

specification to reflect that ASHRAE 

Standard 90.1 delineates DDX–DOAS 

equipment classes, in part, based on 

VERS, and the proposed test procedure 

considers the conditioning contribution 

of the VERS equipment. 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36044 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

33 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. 

DOE is proposing that a basic model 

for a DDX–DOAS means all units 

manufactured by one manufacturer 

within a single equipment class; with 

the same or comparably performing 

compressor(s), heat exchangers, 

ventilation energy recovery system(s) (if 

present), and air moving system(s), and 

with a common ‘‘nominal’’ moisture 

removal capacity. This proposed 

definition of a basic model of a DDX– 

DOAS would be included in the 

regulatory text in 10 CFR 431.92. 

Issue–9: DOE seeks comment on the 

proposed definition of basic model of a 

DDX–DOAS. 

b. Sampling Plan Requirements 

DOE is proposing sampling 

requirements to determine the 

represented values for DDX–DOAS (i.e., 

dehumidification and heating 

efficiencies and MRC). More 

specifically, by proposing to define (at 

10 CFR 431.92) DDX–DOAS as a subset 

of DX–DOAS, and to define DX–DOAS 

as a category of small, large, or very 

large commercial package air 

conditioning and heating equipment, 

the proposal would apply the same 

sampling requirements to DDX–DOASes 

as applicable to other commercial 

package air conditioning and heating 

equipment under 10 CFR 429.43, 

Commercial heating, ventilating, air 

conditioning (HVAC) equipment. 

In response to DOE’s request for 

general comment on issues associated 

with adopting the industry test 

procedures for certain commercial 

package air conditioning and heat pump 

equipment in the July 2017 ASHRAE TP 

RFI (82 FR 34427, 34445 (July 25, 

2017)), Lennox recommended that DOE 

harmonize the certification criteria for 

commercial HVAC equipment in 10 CFR 

429.43 with those for central air 

conditioners, a consumer product, in 10 

CFR 429.16. In particular, Lennox stated 

that commercial equipment currently 

has a more stringent confidence limit of 

95 percent, but the commenter argued 

that current testing technology does not 

support this level of precision. (Lennox, 

No. 8 at p. 6) As DOE is proposing to 

apply the sampling requirements of 10 

CFR 431.43 to DDX–DOASes, Lennox’s 

comment regarding the confidence limit 

for represented values of energy 

efficiency, energy consumption, and 

capacity is relevant to DDX–DOASes. 

Other manufacturers did not raise 

concerns regarding the confidence limit 

required for sampling more typical 

commercial package air conditioning 

and heat pump equipment, and Lennox 

has not provided data regarding 

variability of units in production and 

testing. Absent more specific 

information or data regarding the 

stringency of the confidence level, DOE 

is not proposing a change.33

Issue–10: DOE requests comment on 

the sampling plan proposed for DDX– 

DOASes. DOE specifically requests 

information and data regarding the 

proposed confidence level and whether 

variability of testing of DDX–DOASes 

would require a less stringent level, and 

if so, what that level should be. 

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 specific for 

models approved for use with multiple 

refrigerants. 

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. On the 

other hand, some refrigerants (such as 

R–422D and R–427A) would not require 

different hardware, and a manufacturer 

may consider them to be the same basic 

model. In the latter case of multiple 

refrigerant options, DOE proposes to 

add a new paragraph at 10 CFR 

429.43(a)(3) specifying that a 

manufacturer must determine the 

represented values for that basic model 

based on the refrigerant(s)—among all 

refrigerants listed on the unit’s 

nameplate—that result in the lowest 

ISMRE2 and ISCOP2 efficiencies, 

respectively. For example, the 

dehumidification performance metric 

ISMRE2 must be based on the 

refrigerant yielding the lowest ISMRE2, 

and the heating performance metric 

ISCOP2 (if the unit is a heat pump 

DDX–DOAS) must be based on the 

refrigerant yielding the lowest ISCOP2. 

These represented values would apply 

to the basic model for all refrigerants 

specified by the manufacturer as 

appropriate for use, regardless of which 

one may actually be used in the field, 

where only one set of values is reported. 

DOE notes that this proposal reflects 

the proposed definition of basic model 

for DDX–DOASes as discussed in 

section III.B.4.a of this NOPR. Units 

within a basic model of DDX–DOAS 

must have the same or comparably 

performing compressor(s), heat 

exchangers, ventilation energy recovery 

system(s) (if present), and air moving 

system(s), and with a common 

‘‘nominal’’ moisture removal capacity. 

Issue–11: DOE requests comment on 

its proposal regarding representations 

for models approved for use with 

multiple refrigerants. 

d. Alternative Energy-Efficiency 

Determination Methods 

DOE proposes to allow DDX–DOAS 

manufacturers to use alternative energyefficiency determination methods 

(AEDMs) for determining the ISMRE2 

and ISCOP2 (if applicable) in 

accordance with 10 CFR 429.70. By 

proposing to define (at 10 CFR 431.92) 

DDX–DOAS as a subset of DX–DOAS, 

and to define DX–DOAS as a category of 

small, large, or very large commercial 

package air conditioning and heating 

equipment, the provisions of 10 CFR 

429.43 authorizing use of an AEDM for 

commercial HVAC equipment would 

apply to DDX–DOAS. DOE notes that 

the proposed requirements for use of 

AEDMs to determine DDX–DOAS 

represented values are consistent with 

AEDM requirements for all other 

categories of commercial package airconditioning and heating equipment. 

DOE proposes to create four 

validation classes of DDX–DOASes 

within the Validation classes table at 10 

CFR 429.70(c)(2)(iv): Air-cooled/airsource and water-cooled/water-source, 

each with and without VERS. The 

separation into air-cooled/air-source 

and water-cooled/water source 

validation classes is the same approach 

used for other categories of commercial 

package air-conditioning and heating 

equipment. For DDX–DOASes, the 

additional class separation by presence 

of energy recovery reflects ASHRAE 

Standard 90.1 delineating equipment 

classes, in part, based on the presence 

of VERS and the significant differences 

in the test methods required with energy 

recovery. These differences in the test 

procedures include the potential need 

for a third test chamber for the Option 

1 approach for testing DDX–DOASes 

with energy recovery, and the 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36045 

34Available at: webstore.ansi.org/tandards/ 

ASHRAE/ANSIASHRAEStandard2212020 (Last 

accessed April 19, 2021). 

requirement to account for the 

performance of the energy recovery 

device for the Option 2 approach (see 

section III.B.3.g of this NOPR). 

DOE proposes to require testing of 

two basic models to validate the AEDMs 

for each validation class—this is 

identical to the requirements for other 

categories of commercial package airconditioning and heating equipment. 

Finally, DOE proposes to specify in the 

table at 10 CFR 429.70(c)(5)(vi) a 

tolerance of 10 percent for DDX–DOAS 

verification tests for ISMRE2 and 

ISCOP2 when comparing test results 

with certified ratings. Again, this is 

identical to the tolerances for 

‘‘integrated’’ ratings for other categories 

of commercial package air-conditioning 

and heating equipment. 

Issue–12: DOE requests comment on 

its proposals for AEDM requirements for 

DDX–DOAS equipment. DOE requests 

comment specifically on whether the 

proposed 10-percent tolerance for 

comparison of test results with rated 

values is appropriate. If the 10-percent 

tolerance is not appropriate, DOE 

requests comment on why it is not 

appropriate, as well as comment 

indicating an appropriate tolerance. 

e. Rounding 

Sections 6.1.2.1 through 6.1.2.8 of 

AHRI 920–2020 specify rounding for 

DDX–DOAS performance metrics. DOE 

proposes to adopt these rounding 

requirements as part of the DOE test 

procedure, as enumerated in section 

2.2.1(c)(iv) of the proposed Appendix B. 

Issue–13: DOE requests comment on 

its proposal to adopt the rounding 

requirements for key metrics as 

specified in sections 6.1.2.1 through 

6.1.2.8 of AHRI 920–2020. 

3. Configuration of Unit Under Test 

DOE recognizes that DDX–DOASes 

are distributed in commerce in a variety 

of configurations consisting of different 

combinations of components. DOE 

proposes in section 2.2.1(g) of Appendix 

B to adopt the requirements of appendix 

F to AHRI 920–2020, which includes a 

list of components that must be present 

for testing DDX–DOASes and a list of 

components that are optional for testing. 

Appendix F in AHRI 920–2020 also 

includes explicit instructions on how 

representations can be made for 

equipment that include these optional 

components. AHRI 920–2020 specifies 

the following list of components that 

must be present for testing: 

• Supply air filter(s); 

• Compressor(s); 

• Outdoor coil(s) or heat 

exchanger(s); 

• Outdoor coil fan(s)/motor(s) (for aircooled and air-source systems only); 

• Conditioning coil(s); 

• Refrigerant expansion device(s); 

• Supply/outdoor ventilation fan(s)/ 

motor(s), and 

• System controls. 

AHRI 920–2020 also specifies that for 

supply air filters, the filter shall have a 

‘‘minimum efficiency reporting value’’ 

(MERV) specification no less than 

MERV 8. For individual models that use 

filters with efficiency higher than MERV 

8 (which generally have higher pressure 

drop and could reduce relative tested 

efficiency), section F2.4 of AHRI 920– 

2020 allows manufacturers the option of 

testing these individual models as a 

separate basic model or combined into 

a basic model with other individual 

models that meet the basic model 

definition and are tested with a MERV 

8 filter. Adopting Appendix F of AHRI 

920–2020 without changes would allow 

manufacturers to provide efficiency 

representations based on either testing 

option for individual models that use 

filters with efficiency higher than MERV 

8. 

DOE notes that the list of components 

that are optional for testing specified in 

section F2.4 of AHRI 920–2020 includes 

features that may reduce tested 

efficiency but may also in certain 

applications: (a) Maintain or improve 

field efficiency or (b) be required for 

safety. Given the potential benefits, DOE 

does not want to penalize equipment 

with such components, because that 

might disincentivize their adoption. By 

proposing to adopt Appendix F of AHRI 

920–2020 without changes, the 

following instructions from AHRI 920– 

2020 would specify how to make 

representations for individual models of 

equipment that include these optional 

features: 

• Individual models with features 

designated as ‘‘optional’’ may be 

represented separately as a unique basic 

model or certified within the same basic 

model as otherwise identical individual 

models without the feature pursuant to 

the definition of ‘‘basic model’’ in 

§ 431.92. 

• If an otherwise identical model 

(within the same basic model) without 

the feature is distributed in commerce, 

test the otherwise identical model. 

• If an otherwise identical model 

(within the same basic model) without 

the feature is not distributed in 

commerce, conduct tests with the 

feature present but configured and deactivated so as to minimize (partially or 

totally) the impact on the results of the 

test. Alternatively, the manufacturer 

may indicate in the supplemental 

testing instructions that the test shall be 

conducted using a specially-built 

otherwise identical unit that is not 

distributed in commerce and does not 

have the feature. 

This approach ensures that equipment 

distributed in commerce with additional 

components outside the list of required 

components are still within the scope of 

the test procedure. The proposed 

approach also provides instruction on 

how to make representations for all 

component combinations (including 

those with optional components). In 

addition, this approach allows 

manufacturers the flexibility to make 

representations of equipment with 

components designated as ‘‘optional’’ 

based on testing otherwise identical 

individual models without the feature. 

C. Other Comments 

In response to the July 2017 ASHRAE 

TP RFI, DOE received several general 

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.) 

As noted in section I.A of this 

document, 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)) 

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’’ 34 (ASHRAE 

221–2020) as the applicable test 

procedure corresponding to industry 

standards. NCI also did not provide data 

on field performance or any correlations 

between field performance and 

laboratory test performance for DX– 

DOASes or DDX–DOASes for DOE to 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36046 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

consider. Furthermore, ASHRAE 221– 

2020 does not provide a method to 

determine the dehumidification 

efficiency and heating efficiency of 

DDX–DOASes, as AHRI 920–2020 does. 

As discussed in section II of this 

document, DOE is proposing to 

incorporate by reference AHRI 920– 

2020 (i.e., the test procedure recognized 

by ASHRAE Standard 90.1 for DDX– 

DOASes) and the relevant industry 

standards referenced therein, consistent 

with EPCA requirements. 

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 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.) 

Additionally, the CA IOUs emphasized 

the importance of accurate efficiency 

ratings for its incentive programs and 

customer knowledge, pointing to 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) The commenter stated 

that in commercial applications, 

predicting actual energy use from a 

single metric is difficult and that 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 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 largely dictated by the 

requirements of EPCA. 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 relevant 

industry test procedure is amended, 

DOE must update its test procedure to 

be consistent with the amended 

industry consensus test procedure, 

unless DOE determines, by rule 

published in the Federal Register and 

supported by clear and convincing 

evidence, that the amended test 

procedure would not meet the 

requirements in 42 U.S.C. 6314(a)(2) 

and (3) related to representative use and 

test burden. (42 U.S.C. 6314(a)(4)(B) and 

(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 

are 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 manufacturers’ own 

testing. (Joint Advocates, No. 9 at p. 2) 

In the context of a test procedure for 

DDX–DOASes, DOE addresses the 

potential for ambiguity as applicable, in 

the previous sections of this document. 

D. Test Procedure Costs, Harmonization, 

and Other Topics 

1. Test Procedure Costs and Impact 

EPCA requires DOE to adopt test 

procedures for small, large and very 

large commercial package air 

conditioning and heating equipment 

consistent with the amended industry 

test procedures developed or recognized 

AHRI as referenced in ASHRAE 

Standard 90.1, unless the Secretary 

determines that, supported by clear and 

convincing evidence, to do so would not 

meet the requirements for test 

procedures to be reasonably designed to 

produce results that reflect energy 

efficiency, energy use, and estimated 

operating costs during a representative 

average use cycle and not be unduly 

burdensome to conduct. (42 U.S.C. 

6314(a)(4)(B)) In this NOPR, DOE 

proposes to establish a test procedure 

for DDX–DOASes, which belong to a 

category of small, large, and very large 

commercial package air conditioning 

and heating equipment. DOE is 

proposing to establish a test procedure 

that incorporates by reference the 

applicable industry consensus test 

methods (including the energy 

efficiency descriptors) and that 

establishes representation requirements. 

DOE has tentatively determined that 

these proposed new test procedures 

would be representative of an average 

use cycle and would not be unduly 

burdensome for manufacturers to 

conduct. To the extent that DOE is 

proposing modifications to the industry 

consensus test procedure, DOE has 

tentatively determined that the 

proposed modifications are consistent 

with the industry consensus standard, 

and as explained in the prior sections, 

they are supported by clear and 

convincing evidence, because absent 

such modifications, the industry 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)). Further, DOE has tentatively 

determined that the proposed 

modifications would be unlikely to 

significantly increase burden, given that 

DOE is referencing the prevailing 

industry test procedure. So, presuming 

widespread usage of that test standard, 

its adoption as part of the Federal test 

procedure would be expected to result 

in little additional cost, even with the 

minor modifications proposed here. 

DOE has tentatively determined that the 

test procedure, if finalized as proposed, 

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. 

When the industry test procedure or 

rating procedure for a category of small, 

large, and very large commercial 

package air conditioning and heating 

equipment recognized in ASHRAE 

Standard 90.1 is amended, DOE is 

required to amend the Federal test 

procedure for the relevant category of 

small, large, and very large commercial 

package air conditioning and heating 

equipment consistent with the industry 

update, unless DOE determines by clear 

and convincing evidence that to do so 

would result in a test procedure that 

does not meet the EPCA requirements 

regarding representativeness and testing 

burden. (42 U.S.C. 6314(a)(4)(B)) As 

discussed, ASHRAE Standard 90.1– 

2016 established energy efficiency 

levels for DDX–DOASes (but written as 

‘‘DX–DOASes’’ in ASHRAE Standard 

90.1) as a category of commercial 

package air conditioning and heating 

equipment and recognized ANSI/AHRI 

920–2015 as the industry test procedure 

for these equipment. Subsequent to the 

establishment of standards and a test 

procedure for DDX–DOASes in 

ASHRAE Standard 90.1–2016, ANSI/ 

AHRI 920–2015 was updated. The 2020 

version of AHRI 920 (i.e., AHRI 920– 

2020) is the most recent version of the 

industry test procedure for DDX– 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36047 

DOASes (still referred to in AHRI 920– 

2020 as simply ‘‘DX–DOASes’’). 

DOE is proposing to incorporate by 

reference the revised industry test 

standard, AHRI 920–2020, with certain 

modifications that are consistent with 

the industry test standard. DOE has 

tentatively concluded that the proposed 

test procedure in this NOPR would not 

add undue industry test burden, and 

that the proposed test procedure for this 

equipment is consistent with the 

industry test procedure update. Further 

discussion of the cost impacts of the 

proposed test procedure are presented 

in the following paragraphs. 

As noted previously, currently DOE 

does not prescribe test procedures for 

DDX–DOASes, and AHRI 920–2020 is 

the most recent version of the industry 

test procedure applicable to DDX– 

DOASes. DOE has tentatively 

determined that the proposal to 

incorporate by reference AHRI 920– 

2020 is consistent with current industry 

practice, and, therefore, manufacturers 

would not be expected to incur any 

additional costs if the proposal were 

finalized. Importantly, the proposals in 

this NOPR, if finalized, would not 

require manufacturers to certify ratings 

to DOE. DOE would address 

certification as part of any rulemaking to 

address energy conservation standards 

for DDX–DOASes. 

With that said, DOE is proposing to 

define ‘‘dehumidifying direct 

expansion-dedicated outdoor air 

system’’ (DDX–DOAS) based on the 

definition provided in AHRI 920–2020. 

The differences in the proposed 

definition as compared to the definition 

in AHRI 920–2020 are to provide clarity 

and use terminology consistent with 

DOE’s test procedures for other 

categories of commercial package air 

conditioning and heating equipment. 

DOE is proposing to limit the 

applicability of the proposed test 

procedure to DDX–DOASes with any 

MRC less than 324 lbs. of moisture per 

hour, whereas the scope of AHRI 920– 

2020 is not limited based on MRC. In a 

comment provided in response to the 

July 2017 ASHRAE TP RFI, AHRI stated 

that laboratory limitations may limit 

testing using ANSI/AHRI 920–2015 to 

300 lbs. of moisture per hour at 

Standard Rating Condition A and to 

units not physically larger than more 

typical commercial package air 

conditioning equipment with a capacity 

of 760,000 Btu per hour. (AHRI, No. 11 

at p. 20) As discussed in section III.A.3 

of this document, DOE’s proposal to 

limit the coverage of DDX–DOASes to 

324 lbs. of moisture per hour in the 

DDX–DOAS definition is a direct 

conversion from the maximum cooling 

capacity limit of 760,000 Btu per hour 

(which AHRI notes would be the upper 

limit for laboratory capabilities), and it 

is similar to the suggestion made by 

AHRI. Hence the definitional 

modifications to the industry standard 

will not change the scope of coverage of 

the proposed test procedure as 

compared to the industry standard, and 

if made final, would not result in any 

increase in test burden as compared to 

AHRI 920–2020. 

AHRI 920–2020 does not explicitly 

state the amount of external head 

pressure to use when testing watercooled and water-source DDX–DOASes 

with integral pumps. As noted, there are 

a very limited number of DDX–DOAS 

models with integral pumps on the 

market. DOE is proposing to require 

such units be tested with an external 

head pressure equal to 20 ¥0/+1 feet of 

water column, which is the same level 

of external head pressure used in the 

calculation of the pump effect for DDX– 

DOASes without integral pumps. As 

such, DOE considers this proposal to be 

consistent with industry test procedure 

because it ensures that integral pumps 

are treated in the same way as nonintegral pumps, and as such would not 

increase testing burden as compared to 

current industry practice. 

AHRI 920–2020 also does not 

explicitly provide directions for setting 

up the unit’s control settings at each 

Standard Rating Condition. As 

discussed in section III.B.3.g of this 

document, DOE is proposing a general 

requirement for all control settings to 

remain unchanged for all Standard 

Rating Conditions once system set up 

has been completed, and that 

component operation shall be controlled 

by the unit under test once the 

provisions for rating requirements are 

met. This is likely how DDX–DOASes 

would be tested as per the existing 

instructions in AHRI 920–2020, but 

DOE is providing the additional 

specificity in order to ensure that the 

results of the testing are representative, 

repeatable, and reproducible, and as 

such would not increase testing burden 

as compared to current industry 

practice. 

AHRI 920–2020 incorrectly indicates 

that Equation 20 should be used to 

calculate the degradation coefficient for 

DDX–DOASes with VERS (because 

Equation 21 is indicated to apply for 

DDX–DOASes with VERS). This is 

discussed in further detail in section 

III.B.3.l.ii of this document. DOE is 

proposing to correct this statement to 

instead use this equation for DDX– 

DOASes without VERS, with 

deactivated VERS, or with sensible-only 

VERS tested under Standard Rating 

Conditions other than D. DOE considers 

this proposal to be consistent with the 

intent of the industry test procedure and 

would not increase testing burden as 

compared to AHRI 920–2020. 

DOE’s proposal to provide a 

definition for ‘‘non-standard low-static 

fan motor’’ also serves to provide clarity 

to the instructions present in AHRI 920– 

2020 without affecting the scope of 

coverage or testing burden. Absent this 

definition, as discussed in section 

III.B.3.l.iii of this document, it is not 

possible to determine the appropriate 

airflow setting procedure in section 

6.1.5.2 of AHRI 920–2020. 

AHRI 920–2020 does not provide 

instruction for testing a DDX–DOAS for 

which a manufacturer recommends 

more than one refrigerant option. DOE 

is proposing to require testing of such a 

unit with each recommended refrigerant 

if the different refrigerants require 

different hardware. This proposal is 

consistent with the treatment of basic 

models of commercial packaged air 

conditioners and heating equipment 

under 10 CFR 430.92, and, as such, it 

would be reflective of industry practice 

for commercial packaged air conditioner 

and heating equipment generally. 

Therefore, this proposed addition to the 

procedure laid out by AHRI 920–2020 

would not increase testing burden as 

compared current industry practice. 

DOE is also proposing sampling 

requirements for making representations 

of ISMRE2 and ISCOP2, as applicable. 

AHRI 920–2020 does not contain 

comparable provisions. The sampling 

requirements proposed are consistent 

with the DOE sampling requirements 

generally for commercial packaged air 

conditioners and heating equipment, 

and, if made final, would be reflective 

of industry practice. Therefore, the 

proposed sampling requirements, if 

made final, would not increase testing 

burden as compared to the current 

industry practice. 

Issue–14: DOE requests comment on 

its understanding of the impact of the 

test procedure proposals in this NOPR, 

specifically DOE’s initial conclusion 

that manufacturers would not incur any 

additional costs due to this proposal, if 

finalized, compared to current industry 

practice, as indicated by AHRI 920– 

2020. 

4. Harmonization With Industry 

Standards 

DOE proposes to incorporate by 

reference the provisions in AHRI 920– 

2020, including definitions, test 

methods, and rating requirements, with 

certain modifications previously 

discussed. Throughout this NOPR, DOE 

discusses adopting this most recent 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36048 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

35All 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). 

36For editorial reasons, upon codification in the 

U.S. Code, Part C was redesignated Part A–1. 

relevant industry consensus testing 

standard for DDX–DOAS equipment, as 

required in 42 U.S.C. 6314 and 

discussed in section III.B of this NOPR. 

Issue–15: DOE seeks comment on the 

degree to which the DOE test procedure 

should consider and be harmonized 

further with the most recent relevant 

industry consensus testing standards for 

DDX–DOASes and whether there could 

be modifications to the industry test 

method that would provide additional 

benefits to the public. DOE also requests 

comment on the benefits and burdens of 

adopting any industry/voluntary 

consensus-based or other appropriate 

test procedure, without modification. 

5. Other Test Procedure Topics 

In addition to the issues identified 

earlier in this document, DOE welcomes 

comment on any other aspect of the 

proposed test procedures for DDX– 

DOASes not already addressed by the 

specific areas identified in this 

document. DOE particularly seeks 

information that would ensure that the 

test procedure measures energy 

efficiency during a representative 

average use cycle, as well as information 

that would help DOE create a procedure 

that is not unduly burdensome to 

conduct. 

E. 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)) 

IV. Procedural Issues and Regulatory 

Review 

A. Review Under Executive Order 12866 

The Office of Management and Budget 

(OMB) has determined that this test 

procedure rulemaking does not 

constitute a ‘‘significant regulatory 

actions’’ under section 3(f) of Executive 

Order 12866, ‘‘Regulatory Planning and 

Review,’’ 58 FR 51735 (Oct. 4, 1993). 

Accordingly, this action was not subject 

to review under the Executive Order by 

the Office of Information and Regulatory 

Affairs (OIRA) in OMB. 

B. Review Under the Regulatory 

Flexibility Act 

The Regulatory Flexibility Act (5 

U.S.C. 601 et seq.) requires preparation 

of an initial regulatory flexibility 

analysis (‘‘IRFA’’) for any rule that by 

law must be proposed for public 

comment, unless the agency certifies 

that the rule, if promulgated, will not 

have a significant economic impact on 

a substantial number of small entities. 

As required by Executive Order 13272, 

‘‘Proper Consideration of Small Entities 

in Agency Rulemaking,’’ 67 FR 53461 

(August 16, 2002), DOE published 

procedures and policies on February 19, 

2003, to ensure that the potential 

impacts of its rules on small entities are 

properly considered during the DOE 

rulemaking process. 68 FR 7990. DOE 

has made its procedures and policies 

available on the Office of the General 

Counsel’s website at: energy.gov/gc/ 

office-general-counsel. DOE reviewed 

this proposed rule under the provisions 

of the Regulatory Flexibility Act and the 

policies and procedures published on 

February 19, 2003. 

The following sections detail DOE’s 

IRFA for this test procedure rulemaking. 

1. Description of Reasons Why Action Is 

Being Considered 

DOE is undertaking this test 

procedure rulemaking to establish a 

DOE test procedure for DDX–DOASes in 

response to updates to the relevant 

industry consensus standard, American 

Society of Heating, Refrigerating and 

Air-Conditioning Engineers (ASHRAE) 

Standard 90.1, Energy Standard for 

Buildings Except Low-Rise Residential 

Buildings, which, with its 2016 

publication, both added efficiency 

standards and specified a test procedure 

for this equipment (i.e., AHRI 920– 

2015). Subsequently, the AirConditioning, Heating, and Refrigeration 

Institute (AHRI) updated its test 

procedure with the publication of AHRI 

920–2020. The Energy Policy and 

Conservation Act (EPCA) 35 requires that 

each time the test procedure referenced 

by ASHRAE Standard 90.1 is updated, 

DOE must update the Federal test 

procedure consistent with the industry 

update, unless there is clear and 

convincing evidence that the update 

would not be representative of an 

average use cycle or would be unduly 

burdensome to conduct. 

2. Objectives of, and Legal Basis for, 

Rule 

EPCA, as amended, among other 

things, authorizes DOE to regulate the 

energy efficiency of a number of 

consumer products and certain 

industrial equipment. Title III, Part C36

of EPCA, Public Law 94–163 (42 U.S.C. 

6311–6317, as codified), added by 

Public Law 95–619, Title IV, § 441(a), 

established the Energy Conservation 

Program for Certain Industrial 

Equipment, which sets forth a variety of 

provisions designed to improve energy 

efficiency. This covered equipment 

includes small, large, and very large 

commercial package air conditioning 

and heating equipment. (42 U.S.C. 

6311(1)(B)–(D)) DOE has initially 

determined that commercial package air 

conditioning and heating equipment 

includes DX–DOASes. As discussed in 

section I.B of the NOPR document, DX– 

DOASes had not previously been 

addressed in DOE rulemakings and are 

not currently subject to Federal test 

procedures or energy conservation 

standards. 

Under EPCA, DOE’s energy 

conservation program consists 

essentially of four parts: (1) Testing, (2) 

labeling, (3) Federal energy conservation 

standards, and (4) certification and 

enforcement procedures. Relevant 

provisions of EPCA specifically 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 in limited circumstances for 

particular State laws or regulations, in 

accordance with the procedures and 

other provisions of EPCA. (42 U.S.C. 

6316(b)(2)(D)) 

Under 42 U.S.C. 6314, the statute also 

sets forth the criteria and procedures 

DOE is required to follow when 

prescribing or amending test procedures 

for covered equipment. Specifically, 

EPCA requires that any test procedure 

prescribed or amended shall be 

reasonably designed to produce test 

results which measure energy 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36049 

37The size standards are listed by NAICS code 

and industry description and are available at 

www.sba.gov/document/support--table-sizestandards (Last accessed on April 20, 2021). 

38 DOE has tentatively determined that the 

proposed modifications to AHRI 920–2020 would 

be unlikely to significantly increase burden, given 

that DOE is referencing the prevailing industry test 

procedure. So, presuming widespread usage of 

AHRI 920–2020, its adoption as part of the Federal 

Continued 

efficiency, energy use, or estimated 

annual operating cost of covered 

equipment during a representative 

average use cycle and requires that test 

procedures not be unduly burdensome 

to conduct. (42 U.S.C. 6314(a)(2)) 

EPCA requires that the test 

procedures for commercial package air 

conditioning and heating equipment be 

those generally accepted industry 

testing procedures or rating procedures 

developed or recognized by the AirConditioning, Heating, and Refrigeration 

Institute (AHRI) or by the American 

Society of Heating, Refrigerating and 

Air-Conditioning Engineers (ASHRAE), 

as referenced in ASHRAE Standard 

90.1, ‘‘Energy Standard for Buildings 

Except Low-Rise Residential Buildings’’ 

(ASHRAE Standard 90.1). (42 U.S.C. 

6314(a)(4)(A)) Further, if such an 

industry test procedure is amended, 

DOE must update its test procedure to 

be consistent with the amended 

industry test procedure, unless DOE 

determines, by rule published in the 

Federal Register and supported by clear 

and convincing evidence, that 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)) 

EPCA also requires that, at least once 

every seven years, DOE evaluate test 

procedures for each type of covered 

equipment, including commercial 

package air conditioning and heating 

equipment to determine whether 

amended test procedures would more 

accurately or fully comply with the 

requirements for the test procedures not 

to be unduly burdensome to conduct 

and be reasonably designed to produce 

test results that reflect energy efficiency, 

energy use, and estimated operating 

costs during a representative average 

use cycle. (42 U.S.C. 6314(a)(1)–(3)) In 

addition, if DOE determines that a test 

procedure amendment is warranted, it 

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)) 

A test procedure for a subset of DX– 

DOASes (i.e., DDX–DOASes), was first 

specified by ASHRAE Standard 90.1 in 

the 2016 edition (ASHRAE Standard 

90.1–2016). Pursuant to 42 U.S.C. 

6314(a)(4)(B), and following updates to 

the relevant test procedures which were 

referenced in ASHRAE Standard 90.1, 

DOE is publishing this NOPR proposing 

to establish a test procedure for DDX– 

DOASes in satisfaction of its 

aforementioned obligations under 

EPCA. 

3. Description and Estimate of Small 

Entities Regulated 

For manufacturers of small, large, and 

very large air-conditioning and heating 

equipment (including DDX–DOASes), 

commercial warm-air furnaces, and 

commercial water heaters, the Small 

Business Administration (SBA) has set a 

size threshold which defines those 

entities classified as ‘‘small businesses’’ 

for the purposes of the statute. DOE 

used the SBA’s small business size 

standards to determine whether any 

small entities would be subject to the 

requirements of this rule. See 13 CFR 

part 121. The equipment covered by this 

rule are classified under North 

American Industry Classification 

System (‘‘NAICS’’) code 333415,37 ‘‘AirConditioning and Warm Air Heating 

Equipment and Commercial and 

Industrial Refrigeration Equipment 

Manufacturing.’’ In 13 CFR 121.201, the 

SBA sets a threshold of 1,250 employees 

or fewer for an entity to be considered 

as a small business for this category. 

In reviewing the DDX–DOAS market, 

DOE used company websites, marketing 

research tools, product catalogues, and 

other public information to identify 

companies that manufacture DDX– 

DOASes. DOE identified 16 

manufacturers of DDX–DOASes affected 

by this rulemaking. Out of these 16 

manufacturers, DOE determined that 

three are domestic small businesses. 

DOE used subscription-based business 

information tools to determine 

headcount and revenue of the small 

businesses. 

Issue–16: DOE invites comment on 

the number of domestic small 

businesses producing DDX–DOASes for 

the U.S. market. 

4. Description and Estimate of 

Compliance Requirements 

EPCA requires DOE to adopt test 

procedures for small, large, and very 

large commercial package air 

conditioning and heating equipment 

consistent with the amended industry 

test procedures developed or recognized 

by AHRI as referenced in ASHRAE 

Standard 90.1, unless the Secretary 

determines that, supported by clear and 

convincing evidence, to do so would not 

meet the requirements for test 

procedures to be reasonably designed to 

produce results that reflect energy 

efficiency, energy use, and estimated 

operating costs during a representative 

average use cycle and not be unduly 

burdensome to conduct. (42 U.S.C. 

6314(a)(4)(B)) In this NOPR, DOE 

proposes to establish a test procedure 

for DDX–DOASes, which belong to a 

category of small, large, and very large 

commercial package air conditioning 

and heating equipment. DOE is 

proposing to establish a test procedure 

that incorporates by reference the 

applicable industry consensus test 

methods (including the energy 

efficiency descriptors) and that 

establishes representation requirements. 

Although AHRI 920–2020 is not yet 

referenced as the applicable test 

procedure in ASHRAE Standard 90.1, it 

provides revised test methods that 

update ANSI/AHRI 920–2015, which is 

the referenced industry test standard. 

For these reasons, DOE has tentatively 

concluded that the methods in AHRI 

920–2020 reflect the intention for 

prevalent industry practice: It is likely 

that manufacturers will use AHRI 920– 

2020 in the future. 

In its review of AHRI 920–2020, DOE 

estimated the cost for third-party lab 

testing of basic models to range from 

$10,000 to $23,500 depending on 

validation class, equipment capacity, 

and equipment configuration. However, 

manufactures are not required to 

perform laboratory testing on all basic 

models. DOE proposes to allow DDX– 

DOAS manufacturers to use alternative 

energy-efficiency determination 

methods (AEDMs) for determining the 

ISMRE2 and ISCOP2 (if applicable) in 

accordance with 10 CFR 429.70. An 

AEDM is a computer modeling or 

mathematical tool that predicts the 

performance of non-tested basic models. 

These computer modeling and 

mathematical tools, when properly 

developed, can provide a relatively 

straight-forward and reasonably 

accurate means to predict the energy 

usage or efficiency characteristics of a 

basic model of a given covered product 

or equipment and reduce the burden 

and cost associated with testing. 

DOE researched manufacturer DDX– 

DOAS offerings and estimated the cost 

to rate basic models according to the 

proposed DOE test procedure (which is 

not expected to have any additional cost 

over AHRI 920–2020 38). Using 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36050 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

test procedure would be expected to result in little 

additional cost, even with the minor modifications 

proposed by DOE. 

information collected on small business 

equipment offerings and the upper 

threshold of third-party testing costs, 

DOE estimates an average expense of 

approximately $200,000 per small 

manufacturer. These testing expenses 

would be less than 1% of revenue for 

each small business. DOE tentatively 

concludes that the estimate costs would 

not present a significant burden to small 

manufacturers. 

The testing of DDX–DOASes would 

not be required until such time as DOE 

establishes DDX–DOAS energy 

conservation standards and 

manufacturers are required to comply 

with those energy conservation 

standards. As such, small manufacturers 

will have a substantial timeframe to 

prepare for the testing detailed in this 

NOPR. Additionally, small 

manufacturers already testing to AHRI 

920–2020 would incur no additional 

costs as a result of this proposed test 

procedure. 

Issue–17: DOE invites comment on 

the testing costs and timing of testing 

costs described in this IRFA. 

5. Duplication, Overlap, and Conflict 

With Other Rules and Regulations 

DOE is not aware of any rules or 

regulations that duplicate, overlap, or 

conflict with the proposed rule being 

considered in this action. 

6. Significant Alternatives to the Rule 

DOE proposes to reduce burden on 

manufacturers, including small 

businesses, by allowing alternative 

energy efficiency or energy use 

determination methods (AEDMs) in lieu 

of physical testing all basic models. An 

AEDM is a computer modeling or 

mathematical tool that predicts the 

performance of non-tested basic models. 

The use of computer modeling is more 

time-efficient than physical testing. 

Without AEDMs, the average cost to rate 

all basic models would exceed $29 

million per small manufacturer, as 

compared to the $200,000 per small 

manufacturer in the current proposal. 

Additionally, DOE considered 

alternative test methods and 

modifications to the test procedure for 

DDX–DOASes, and the Department has 

tentatively determined that there are no 

better alternatives than the 

modifications and test procedures 

proposed in this NOPR, in terms of both 

meeting the agency’s objectives and 

reducing burden. DOE examined 

relevant industry test standards, and the 

Department incorporated these 

standards in the proposed test 

procedures whenever appropriate to 

reduce test burden to manufacturers. 

Specifically, this NOPR proposes that 

DOE establish a test procedure for DDX– 

DOASes through incorporation by 

reference of AHRI 920–2020 with 

modifications that are not expected to 

increase test burden. 

In addition, individual manufacturers 

may petition for a waiver of the 

applicable test procedure. (See 10 CFR 

431.401.) Also, Section 504 of the 

Department of Energy Organization Act, 

42 U.S.C. 7194, provides authority for 

the Secretary to adjust a rule issued 

under EPCA in order to prevent ‘‘special 

hardship, inequity, or unfair 

distribution of burdens’’ that may be 

imposed on that manufacturer as a 

result of such rule. Manufacturers 

should refer to 10 CFR part 1003 for 

additional details. 

C. Review Under the Paperwork 

Reduction Act of 1995 

Manufacturers of certain commercial 

package air condition and heating 

equipment must certify to DOE that 

their products comply with any 

applicable energy conservation 

standards. To certify compliance, 

manufacturers must first obtain test data 

for their products according to the DOE 

test procedures, including any 

amendments adopted for those test 

procedures. DOE has established 

regulations for the certification and 

recordkeeping requirements for all 

covered consumer products and 

commercial/industrial equipment, 

including commercial package air 

condition and heating equipment. (See 

generally 10 CFR part 429.) The 

collection-of-information requirement 

for the certification and recordkeeping 

is subject to review and approval by 

OMB under the Paperwork Reduction 

Act (PRA). This requirement has been 

approved by OMB under OMB control 

number 1910–1400. Public reporting 

burden for the certification is estimated 

to average 35 hours per response, 

including the time for reviewing 

instructions, searching existing data 

sources, gathering and maintaining the 

data needed, and completing and 

reviewing the collection of information. 

Notwithstanding any other provision 

of the law, no person is required to 

respond to, nor shall any person be 

subject to a penalty for failure to comply 

with, a collection of information subject 

to the requirements of the PRA, unless 

that collection of information displays a 

currently valid OMB Control Number. 

D. Review Under the National 

Environmental Policy Act of 1969 

DOE is analyzing this proposed 

regulation in accordance with the 

National Environmental Policy Act of 

1969 (NEPA) and DOE’s NEPA 

implementing regulations (10 CFR part 

1021). DOE anticipates that this 

rulemaking qualifies for categorical 

exclusion A6 because it is a procedural 

rulemaking and meets the requirements 

for application of a categorical 

exclusion. 10 CFR part 1021, subpart D, 

Appendix A, section A6; See 10 CFR 

1021.410. DOE will complete its NEPA 

review before issuing the final rule. 

E. Review Under Executive Order 13132 

Executive Order 13132, ‘‘Federalism,’’ 

64 FR 43255 (August 4, 1999), imposes 

certain requirements on Federal 

agencies formulating and implementing 

policies or regulations that preempt 

State law or that have Federalism 

implications. The Executive Order 

requires agencies to examine the 

constitutional and statutory authority 

supporting any action that would limit 

the policymaking discretion of the 

States and to carefully assess the 

necessity for such actions. The 

Executive Order also requires agencies 

to have an accountable process to 

ensure meaningful and timely input by 

State and local officials in the 

development of regulatory policies that 

have Federalism implications. On 

March 14, 2000, DOE published a 

statement of policy describing the 

intergovernmental consultation process 

it will follow in the development of 

such regulations. 65 FR 13735. DOE has 

examined this proposed rule and has 

tentatively determined that it would not 

have a substantial direct effect on the 

States, on the relationship between the 

national government and the States, or 

on the distribution of power and 

responsibilities among the various 

levels of government. EPCA governs and 

prescribes Federal preemption of State 

regulations as to energy conservation for 

the products that are the subject of this 

proposed rule. States can petition DOE 

for exemption from such preemption to 

the extent, and based on criteria, set 

forth in EPCA. (42 U.S.C. 6297(d)) No 

further action is required by Executive 

Order 13132. 

F. Review Under Executive Order 12988 

Regarding the review of existing 

regulations and the promulgation of 

new regulations, section 3(a) of 

Executive Order 12988, ‘‘Civil Justice 

Reform,’’ 61 FR 4729 (Feb. 7, 1996), 

imposes on Federal agencies the general 

duty to adhere to the following 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36051 

requirements: (1) Eliminate drafting 

errors and ambiguity; (2) write 

regulations to minimize litigation; (3) 

provide a clear legal standard for 

affected conduct rather than a general 

standard, and (4) promote simplification 

and burden reduction. Section 3(b) of 

Executive Order 12988 specifically 

requires that Executive agencies make 

every reasonable effort to ensure that the 

regulation: (1) Clearly specifies the 

preemptive effect, if any; (2) clearly 

specifies any effect on existing Federal 

law or regulation; (3) provides a clear 

legal standard for affected conduct 

while promoting simplification and 

burden reduction; (4) specifies the 

retroactive effect, if any; (5) adequately 

defines key terms, and (6) addresses 

other important issues affecting clarity 

and general draftsmanship under any 

guidelines issued by the Attorney 

General. Section 3(c) of Executive Order 

12988 requires Executive agencies to 

review regulations in light of applicable 

standards in sections 3(a) and 3(b) to 

determine whether they are met or it is 

unreasonable to meet one or more of 

them. DOE has completed the required 

review and determined that, to the 

extent permitted by law, the proposed 

rule meets the relevant standards of 

Executive Order 12988. 

G. Review Under the Unfunded 

Mandates Reform Act of 1995 

Title II of the Unfunded Mandates 

Reform Act of 1995 (UMRA) requires 

each Federal agency to assess the effects 

of Federal regulatory actions on State, 

local, and Tribal governments and the 

private sector. Public Law 104–4, sec. 

201 (codified at 2 U.S.C. 1531). For a 

proposed regulatory action likely to 

result in a rule that may cause the 

expenditure by State, local, and Tribal 

governments, in the aggregate, or by the 

private sector of $100 million or more 

in any one year (adjusted annually for 

inflation), section 202 of UMRA requires 

a Federal agency to publish a written 

statement that estimates the resulting 

costs, benefits, and other effects on the 

national economy. (2 U.S.C. 1532(a), (b)) 

The UMRA also requires a Federal 

agency to develop an effective process 

to permit timely input by elected 

officers of State, local, and Tribal 

governments on a proposed ‘‘significant 

intergovernmental mandate,’’ and 

requires an agency plan for giving notice 

and opportunity for timely input to 

potentially affected small governments 

before establishing any requirements 

that might significantly or uniquely 

affect small governments. On March 18, 

1997, DOE published a statement of 

policy on its process for 

intergovernmental consultation under 

UMRA. 62 FR 12820; also available at 

energy.gov/gc/office-general-counsel. 

DOE examined this proposed rule 

according to UMRA and its statement of 

policy and determined that the rule 

contains neither an intergovernmental 

mandate, nor a mandate that may result 

in the expenditure of $100 million or 

more in any year, so these requirements 

do not apply. 

H. Review Under the Treasury and 

General Government Appropriations 

Act, 1999 

Section 654 of the Treasury and 

General Government Appropriations 

Act, 1999 (Pub. L. 105–277) requires 

Federal agencies to issue a Family 

Policymaking Assessment for any rule 

that may affect family well-being. This 

proposed rule would not have any 

impact on the autonomy or integrity of 

the family as an institution. 

Accordingly, DOE has concluded that it 

is not necessary to prepare a Family 

Policymaking Assessment. 

I. Review Under Executive Order 12630 

DOE has determined, under Executive 

Order 12630, ‘‘Governmental Actions 

and Interference with Constitutionally 

Protected Property Rights,’’ 53 FR 8859 

(March 18, 1988), that this proposed 

regulation would not result in any 

takings that might require compensation 

under the Fifth Amendment to the U.S. 

Constitution. 

J. Review Under Treasury and General 

Government Appropriations Act, 2001 

Section 515 of the Treasury and 

General Government Appropriations 

Act, 2001 (44 U.S.C. 3516 note) provides 

for agencies to review most 

disseminations of information to the 

public under guidelines established by 

each agency pursuant to general 

guidelines issued by OMB. OMB’s 

guidelines were published at 67 FR 

8452 (Feb. 22, 2002), and DOE’s 

guidelines were published at 67 FR 

62446 (Oct. 7, 2002). DOE has reviewed 

this proposed rule under the OMB and 

DOE guidelines and has concluded that 

it is consistent with applicable policies 

in those guidelines. 

K. Review Under Executive Order 13211 

Executive Order 13211, ‘‘Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use,’’ 66 FR 28355 (May 

22, 2001), requires Federal agencies to 

prepare and submit to OMB, a 

Statement of Energy Effects for any 

proposed significant energy action. A 

‘‘significant energy action’’ is defined as 

any action by an agency that 

promulgated or is expected to lead to 

promulgation of a final rule, and that: 

(1) Is a significant regulatory action 

under Executive Order 12866, or any 

successor order; and (2) is likely to have 

a significant adverse effect on the 

supply, distribution, or use of energy; or 

(3) is designated by the Administrator of 

OIRA as a significant energy action. For 

any proposed significant energy action, 

the agency must give a detailed 

statement of any adverse effects on 

energy supply, distribution, or use 

should the proposal be implemented, 

and of reasonable alternatives to the 

action and their expected benefits on 

energy supply, distribution, and use. 

The proposed regulatory action to 

adopt a test procedure for measuring the 

energy efficiency of DDX–DOASes is not 

a significant regulatory action under 

Executive Order 12866. Moreover, it 

would not have a significant adverse 

effect on the supply, distribution, or use 

of energy, nor has it been designated as 

a significant energy action by the 

Administrator of OIRA. Therefore, it is 

not a significant energy action, and, 

accordingly, DOE has not prepared a 

Statement of Energy Effects. 

L. Review Under Section 32 of the 

Federal Energy Administration Act of 

1974 

Under section 301 of the Department 

of Energy Organization Act (Pub. L. 95– 

91; 42 U.S.C. 7101), DOE must comply 

with section 32 of the Federal Energy 

Administration Act of 1974, as amended 

by the Federal Energy Administration 

Authorization Act of 1977. (15 U.S.C. 

788; FEAA) Section 32 essentially 

provides in relevant part that, where a 

proposed rule authorizes or requires use 

of commercial standards, the notice of 

proposed rulemaking must inform the 

public of the use and background of 

such standards. In addition, section 

32(c) requires DOE to consult with the 

Attorney General and the Chairman of 

the Federal Trade Commission (FTC) 

concerning the impact of the 

commercial or industry standards on 

competition. 

The proposed test procedure for 

DDX–DOASes incorporate the following 

applicable industry consensus 

standards: AHRI 920–2020, ANSI/AHRI 

1060–2018, ANSI/ASHRAE 37–2009, 

ANSI/ASHRAE 41.1–2013, ANSI/ 

ASHRAE 41.6–2014, and ANSI/ 

ASHRAE 198–2013. DOE has evaluated 

these standards and is unable to 

conclude whether they fully comply 

with the requirements of section 32(b) of 

the FEAA (i.e., whether they were 

developed in a manner that fully 

provides for public participation, 

comment, and review). DOE will 

consult with both the Attorney General 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36052 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

and the Chairman of the FTC 

concerning the impact of these test 

procedures on competition, prior to 

prescribing a final rule. 

M. Description of Materials 

Incorporated by Reference 

In this NOPR, DOE proposes to 

incorporate by reference the following 

test standards: 

(1) The test standard published by 

AHRI, titled ‘‘2020 Standard for 

Performance Rating of DX-Dedicated 

Outdoor Air System Units,’’ AHRI 

Standard 920–2020 (I–P). AHRI 

Standard 920–2020 (I–P) is an industryaccepted test procedure for measuring 

the performance of DX-dedicated 

outdoor air system units. AHRI 

Standard 920–2020 (I–P) is available on 

AHRI’s website at: www.ahrinet.org/ 

App_Content/ahri/files/STANDARDS/ 

AHRI/AHRI_Standard_920_I-P_

2020.pdf. 

(2) The test standard published by 

AHRI, titled ‘‘2018 Standard for 

Performance Rating of Air-to-Air 

Exchangers for Energy Recovery 

Ventilation Equipment,’’ ANSI/AHRI 

Standard 1060–2018. ANSI/AHRI 

Standard 1060–2018 is an industryaccepted test procedure for measuring 

the performance of air-to-air exchangers 

for energy recovery ventilation 

equipment. ANSI/AHRI Standard 1060– 

2018 is available on AHRI’s website at: 

www.ahrinet.org/App_Content/ahri/ 

files/STANDARDS/AHRI/AHRI_

Standard_1060_I-P_2018.pdf. 

(3) The test standard test standard 

published by ASHRAE, titled ‘‘Methods 

of Testing for Rating Electrically Driven 

Unitary Air-Conditioning and Heat 

Pump Equipment,’’ ANSI/ASHRAE 

Standard 37–2009. ANSI/ASHRAE 

Standard 37–2009 is an industryaccepted test procedure for measuring 

the performance of electrically driven 

unitary air-conditioning and heat pump 

equipment. ANSI/ASHRAE Standard 

37–2009 is available on ASHRAE’s 

website (in partnership with Techstreet) 

at: www.techstreet.com/ashrae/ 

standards/ashrae-37-2009?product_

id=1650947. 

(4) The test standard published by 

ASHRAE, titled ‘‘Standard Method for 

Temperature Measurement,’’ ANSI/ 

ASHRAE Standard 41.1–2013. ANSI/ 

AHRAE Standard 41.1–2013 is an 

industry-accepted test procedure for 

measuring temperature. ANSI/ASHRAE 

Standard 41.1–2013 is available on 

ASHRAE’s website (in partnership with 

Techstreet) at: www.techstreet.com/ 

ashrae/standards/ashrae-41-1- 

2013?product_id=1853241. 

(5) The test standard published by 

ASHRAE, titled ‘‘Standard Method for 

Humidity Measurement,’’ ANSI/ 

ASHRAE Standard 41.6–2014. ANSI/ 

AHRAE Standard 41.6–2014 is an 

industry-accepted test procedure for 

measuring humidity. ANSI/ASHRAE 

Standard 41.6–2014 is available on 

ASHRAE’s website (in partnership with 

Techstreet) at: www.techstreet.com/ 

ashrae/standards/ashrae-41-6- 

2014?product_id=1881840. 

(6) The test standard published by 

ASHRAE, titled ‘‘Method for Test for 

Rating DX-Dedicated Outdoor Air 

Systems for Moisture Removal Capacity 

and Moisture Removal Efficiency,’’ 

ANSI/ASHRAE Standard 198–2013. 

ANSI/ASHRAE Standard 198–2013 is 

an industry-accepted test procedure for 

measuring the performance of DXdedicated outdoor air system units. 

ANSI/ASHRAE Standard 198–2013 is 

available on ASHRAE’s website (in 

partnership with Techstreet) at: 

www.techstreet.com/ashrae/standards/ 

ashrae-198-2013?product_id=1852612. 

V. Public Participation 

A. Participation in the Webinar 

The time and date of the webinar are 

listed in the DATES section at the 

beginning of this document. Webinar 

registration information, participant 

instructions, and information about the 

capabilities available to webinar 

participants will be published on DOE’s 

website: www.energy.gov/eere/ 

buildings/public-meetings-andcomment-deadlines. Participants are 

responsible for ensuring their systems 

are compatible with the webinar 

software. Additionally, you may request 

an in-person meeting to be held prior to 

the close of the request period provided 

in the DATES section of this document. 

Requests for an in-person meeting may 

be made by contacting Appliance and 

Equipment Standards Program staff at 

(202) 287–1445 or by email: Appliance_

Standards_Public_Meetings@ee.doe.gov. 

B. Procedure for Submitting Prepared 

General Statements for Distribution 

Any person who has an interest in the 

topics addressed in this notice, or who 

is representative of a group or class of 

persons that has an interest in these 

issues, may request an opportunity to 

make an oral presentation at the 

webinar/public meeting. Such persons 

may submit requests to speak via email 

to the Appliance and Equipment 

Standards Program at: 

ApplianceStandardsQuestions@

ee.doe.gov. Persons who wish to speak 

should include with their request a 

computer file in WordPerfect, Microsoft 

Word, PDF, or text (ASCII) file format 

that briefly describes the nature of their 

interest in this rulemaking and the 

topics they wish to discuss. Such 

persons should also provide a daytime 

telephone number where they can be 

reached. 

Persons requesting to speak should 

briefly describe the nature of their 

interest in this rulemaking and provide 

a telephone number for contact. DOE 

requests persons selected to make an 

oral presentation to submit an advance 

copy of their statements at least two 

weeks before the webinar/public 

meeting. At its discretion, DOE may 

permit persons who cannot supply an 

advance copy of their statement to 

participate, if those persons have made 

advance alternative arrangements with 

the Building Technologies Office. As 

necessary, requests to give an oral 

presentation should ask for such 

alternative arrangements. 

C. Conduct of the Webinar 

DOE will designate a DOE official to 

preside at the webinar meeting and may 

also use a professional facilitator to aid 

discussion. The meeting will not be a 

judicial or evidentiary-type public 

hearing, but DOE will conduct it in 

accordance with section 336 of EPCA 

(42 U.S.C. 6306). A court reporter will 

be present to record the proceedings and 

prepare a transcript. DOE reserves the 

right to schedule the order of 

presentations and to establish the 

procedures governing the conduct of the 

webinar/public meeting. There shall not 

be discussion of proprietary 

information, costs or prices, market 

share, or other commercial matters 

regulated by U.S. anti-trust laws. After 

the webinar/public meeting and until 

the end of the comment period, 

interested parties may submit further 

comments on the proceedings and any 

aspect of the rulemaking. 

The webinar/public meeting will be 

conducted in an informal, conference 

style. DOE will present summaries of 

comments received before the webinar/ 

public meeting, allow time for prepared 

general statements by participants, and 

encourage all interested parties to share 

their views on issues affecting this 

rulemaking. Each participant will be 

allowed to make a general statement 

(within time limits determined by DOE), 

before the discussion of specific topics. 

DOE will permit, as time permits, other 

participants to comment briefly on any 

general statements. 

At the end of all prepared statements 

on a topic, DOE will permit participants 

to clarify their statements briefly and 

comment on statements made by others. 

Participants should be prepared to 

answer questions by DOE and by other 

participants concerning these issues. 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36053 

39 DOE has historically provided a 75-day 

comment period for test procedure NOPRs pursuant 

to the North American Free Trade Agreement, U.S.- 

Canada-Mexico (‘‘NAFTA’’), Dec. 17, 1992, 32 

I.L.M. 289 (1993); the North American Free Trade 

Agreement Implementation Act, Public Law 103– 

182, 107 Stat. 2057 (1993) (codified as amended at 

10 U.S.C.A. 2576) (1993) (‘‘NAFTA Implementation 

Act’’); and Executive Order 12889, ‘‘Implementation 

of the North American Free Trade Agreement,’’ 58 

FR 69681 (Dec. 30, 1993). However, on July 1, 2020, 

the Agreement between the United States of 

America, the United Mexican States, and the United 

Canadian States (‘‘USMCA’’), Nov. 30, 2018, 134 

Stat. 11 (i.e., the successor to NAFTA), went into 

effect, and Congress’s action in replacing NAFTA 

through the USMCA Implementation Act, 19 U.S.C. 

4501 et seq. (2020), implies the repeal of E.O. 12889 

and its 75-day comment period requirement for 

technical regulations. Thus, the controlling laws are 

EPCA and the USMCA Implementation Act. 

Consistent with EPCA’s public comment period 

requirements for consumer products, the USMCA 

only requires a minimum comment period of 60 

days. Consequently, DOE now provides a 60-day 

public comment period for test procedure NOPRs. 

DOE representatives may also ask 

questions of participants concerning 

other matters relevant to this 

rulemaking. The official conducting the 

webinar/public meeting will accept 

additional comments or questions from 

those attending, as time permits. The 

presiding official will announce any 

further procedural rules or modification 

of the above procedures that may be 

needed for the proper conduct of the 

webinar/public meeting. 

A transcript of the webinar/public 

meeting will be included in the docket, 

which can be viewed as described in the 

Docket section at the beginning of this 

NOPR. In addition, any person may buy 

a copy of the transcript from the 

transcribing reporter. 

D. Submission of Comments 

DOE will accept comments, data, and 

information regarding this proposed 

rule no later than the date provided in 

the DATES section at the beginning of 

this proposed rule.39 Interested parties 

may submit comments using any of the 

methods described in the ADDRESSES

section at the beginning of this 

document. 

Submitting comments via 

www.regulations.gov. The 

www.regulations.gov web page will 

require you to provide your name and 

contact information. Your contact 

information will be viewable to DOE 

Building Technologies staff only. Your 

contact information will not be publicly 

viewable except for your first and last 

names, organization name (if any), and 

submitter representative name (if any). 

If your comment is not processed 

properly because of technical 

difficulties, DOE will use this 

information to contact you. If DOE 

cannot read your comment due to 

technical difficulties and cannot contact 

you for clarification, DOE may not be 

able to consider your comment. 

However, your contact information 

will be publicly viewable if you include 

it in the comment or in any documents 

attached to your comment. Any 

information that you do not want to be 

publicly viewable should not be 

included in your comment, nor in any 

document attached to your comment. 

Persons viewing comments will see only 

first and last names, organization 

names, correspondence containing 

comments, and any documents 

submitted with the comments. 

Do not submit to www.regulations.gov 

information for which disclosure is 

restricted by statute, such as trade 

secrets and commercial or financial 

information (hereinafter referred to as 

Confidential Business Information 

(CBI)). Comments submitted through 

www.regulations.gov cannot be claimed 

as CBI. Comments received through the 

website will waive any CBI claims for 

the information submitted. For 

information on submitting CBI, see the 

Confidential Business Information 

section. 

DOE processes submissions made 

through www.regulations.gov before 

posting. Normally, comments will be 

posted within a few days of being 

submitted. However, if large volumes of 

comments are being processed 

simultaneously, your comment may not 

be viewable for up to several weeks. 

Please keep the comment tracking 

number that www.regulations.gov 

provides after you have successfully 

uploaded your comment. 

Submitting comments via email. 

Comments and documents submitted 

via email also will be posted to 

www.regulations.gov. If you do not want 

your personal contact information to be 

publicly viewable, do not include it in 

your comment or any accompanying 

documents. Instead, provide your 

contact information in a cover letter. 

Include your first and last names, email 

address, telephone number, and 

optional mailing address. The cover 

letter will not be publicly viewable as 

long as it does not include any 

comments. 

Include contact information each time 

you submit comments, data, documents, 

and other information to DOE. No 

telefacsimiles (faxes) will be accepted. 

Comments, data, and other 

information submitted to DOE 

electronically should be provided in 

PDF (preferred), Microsoft Word or 

Excel, WordPerfect, or text (ASCII) file 

format. Provide documents that are not 

secured, written in English, and free of 

any defects or viruses. Documents 

should not contain special characters or 

any form of encryption, and, if possible, 

they should carry the electronic 

signature of the author. 

Campaign form letters. Please submit 

campaign form letters by the originating 

organization in batches of between 50 to 

500 form letters per PDF or as one form 

letter with a list of supporters’ names 

compiled into one or more PDFs. This 

reduces comment processing and 

posting time. 

Confidential Business Information. 

Pursuant to 10 CFR 1004.11, any person 

submitting information that he or she 

believes to be confidential and exempt 

by law from public disclosure should 

submit via email two well-marked 

copies: One copy of the document 

marked ‘‘confidential’’ including all the 

information believed to be confidential, 

and one copy of the document marked 

‘‘non-confidential’’ with the information 

believed to be confidential deleted. DOE 

will make its own determination about 

the confidential status of the 

information and treat it according to its 

determination. 

It is DOE’s policy that all comments 

may be included in the public docket, 

without change and as received, 

including any personal information 

provided in the comments (except 

information deemed to be exempt from 

public disclosure). 

E. Issues on Which DOE Seeks Comment 

Although DOE welcomes comments 

on any aspect of this proposal, DOE is 

particularly interested in receiving 

comments and views of interested 

parties concerning the following issues: 

Issue–1: DOE requests comment on 

the proposed definition for ‘‘direct 

expansion-dedicated outdoor air 

system.’’ DOE also requests comment on 

any additional characteristics not yet 

considered that could help to 

distinguish DX–DOASes from other 

commercial package air conditioning 

and heating equipment. 

Issue–2: DOE requests comment on 

the proposed definition for 

‘‘dehumidifying direct expansiondedicated outdoor air system.’’ 

Specifically, DOE requests comment on 

the proposed criteria for distinguishing 

a ‘‘dehumidifying direct expansiondedicated outdoor air system’’ from a 

‘‘direct expansion-dedicated outdoor air 

system’’ more generally. DOE also 

requests comment on any additional 

characteristics not yet considered that 

could help to distinguish DDX–DOASes 

from DX–DOASes more generally. 

Issue–3: DOE seeks comment on its 

translation of Btu per hour to MRC and 

specifically its proposal to translate the 

upper capacity limit for DDX–DOASes 

such that a model would be considered 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36054 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

in scope if it has an MRC less than 324 

lbs. per hour. 

Issue–4: DOE requests comment on its 

proposal to clarify what terms are 

synonymous with DDX–DOAS. 

Issue–5: DOE requests comment and 

data on the development of a crosswalk 

from the efficiency levels in ASHRAE 

Standard 90.1 based on ANSI/AHRI 

920–2015 to efficiency levels based on 

AHRI 920–2020. DOE is specifically 

seeking data on how dehumidification 

and heating efficiency ratings for a given 

DDX–DOAS model are impacted when 

measured using AHRI 920–2020 as 

compared to ANSI/AHRI 920–2015. 

Issue–6: DOE requests comment on 

the terminology DOE proposes to use for 

DDX–DOASes, including ‘‘integrated 

seasonal coefficient of performance 2, or 

ISCOP2;’’ ‘‘integrated seasonal moisture 

removal efficiency 2, or ISMRE2;’’ and 

‘‘ventilation energy recovery system, or 

VERS.’’ 

Issue–7: DOE requests comment on 

the proposal to require that watercooled and water-source DDX–DOASes 

with integral pumps be set up with an 

external pressure rise equal to 20 feet of 

water column with a condition 

tolerance of ¥0/+1 foot and an 

operating tolerance of 1 foot. 

Issue–8: DOE requests comment on 

the proposed general control setting 

requirement for DDX–DOASes. 

Issue–9: DOE is requesting comment 

on the proposed definition of ‘‘nonstandard low-static fan motor’’ and 

whether the proposed definition reflects 

stakeholder understanding of the term. 

Issue–10: DOE seeks comment on the 

proposed definition of basic model of a 

DDX–DOAS. 

Issue–11: DOE requests comment on 

the sampling plan proposed for DDX– 

DOASes. DOE specifically requests 

information and data regarding the 

proposed confidence level and whether 

variability of testing of DDX–DOASes 

would require a less stringent level, and 

if so, what that level should be. 

Issue–12: DOE requests comment on 

its proposal regarding representations 

for models approved for use with 

multiple refrigerants. 

Issue–13: DOE requests comment on 

its proposals for AEDM requirements for 

DDX–DOAS equipment. DOE requests 

comment specifically on whether the 

proposed 10-percent tolerance for 

comparison of test results with rated 

values is appropriate. If the 10-percent 

tolerance is not appropriate, DOE 

requests comment on why it is not 

appropriate, as well as comment 

indicating an appropriate tolerance. 

Issue–14: DOE requests comment on 

its proposal to adopt the rounding 

requirements for key metrics as 

specified in sections 6.1.2.1 through 

6.1.2.8 of AHRI 920–2020. 

Issue–15: DOE requests comment on 

its understanding of the impact of the 

test procedure proposals in this NOPR, 

specifically DOE’s initial conclusion 

that manufacturers would not incur any 

additional costs due to this proposal, if 

finalized, compared to current industry 

practice, as indicated by AHRI 920– 

2020. 

Issue–16: DOE seeks comment on the 

degree to which the DOE test procedure 

should consider and be harmonized 

further with the most recent relevant 

industry consensus testing standards for 

DDX–DOASes and whether there could 

be modifications to the industry test 

method that would provide additional 

benefits to the public. DOE also requests 

comment on the benefits and burdens of 

adopting any industry/voluntary 

consensus-based or other appropriate 

test procedure, without modification. 

Issue–17: DOE invites comment on 

the number of domestic small 

businesses producing DDX–DOASes for 

the U.S. market. 

Issue–18: DOE invites comment on 

the testing costs and timing of testing 

costs described in this IRFA. 

VI. Approval of the Office of the 

Secretary 

The Secretary of Energy has approved 

publication of this proposed rule. 

List of Subjects 

10 CFR Part 429 

Administrative practice and 

procedure, Confidential business 

information, Energy conservation, 

Household appliances, Imports, 

Incorporation by reference, 

Intergovernmental relations, Reporting 

and recordkeeping requirements, Small 

businesses. 

10 CFR Part 431 

Administrative practice and 

procedure, Confidential business 

information, Energy conservation, 

Incorporation by reference, Reporting 

and recordkeeping requirements. 

Signing Authority 

This document of the Department of 

Energy was signed on June 23, 2021, by 

Kelly Speakes-Backman, Principal 

Deputy Assistant Secretary and Acting 

Assistant Secretary for Energy Efficiency 

and Renewable Energy, pursuant to 

delegated authority from the Secretary 

of Energy. That document with the 

original signature and date is 

maintained by DOE. For administrative 

purposes only, and in compliance with 

requirements of the Office of the Federal 

Register, the undersigned DOE Federal 

Register Liaison Officer has been 

authorized to sign and submit the 

document in electronic format for 

publication, as an official document of 

the Department of Energy. This 

administrative process in no way alters 

the legal effect of this document upon 

publication in the Federal Register. 

Signed in Washington, DC, on June 23, 

2021. 

Treena V. Garrett, 

Federal Register Liaison Officer, U.S. 

Department of Energy. 

For the reasons stated in the 

preamble, DOE is proposing to amend 

parts 429 and 431 of chapter II of title 

10, Code of Federal Regulations as set 

forth below: 

PART 429—CERTIFICATION, 

COMPLIANCE, AND ENFORCEMENT 

FOR CONSUMER PRODUCTS AND 

COMMERCIAL AND INDUSTRIAL 

EQUIPMENT 

■ 1. The authority citation for part 429 

continues to read as follows: 

Authority: 42 U.S.C. 6291–6317; 28 U.S.C. 

2461 note. 

■ 2. Amend § 429.43 by adding 

paragraph (a)(3) to read as follows: 

§ 429.43 Commercial heating, ventilating, 

air conditioning (HVAC) equipment. 

(a) * * * 

(3) Refrigerants: For dehumidifying 

direct expansion-dedicated outdoor air 

systems (DDX–DOASes), if a basic 

model is distributed in commerce for 

which the manufacturer specifies the 

use of more than one refrigerant option, 

the ISMRE2 and ISCOP2, as applicable, 

are determined for that basic model 

using the refrigerant that results in the 

lowest ISMRE2 and the refrigerant that 

results in the lowest ISCOP2, as 

applicable. For example, the 

dehumidification performance metric 

ISMRE2 must be based on the 

refrigerant yielding the lowest ISMRE2, 

and the heating performance metric 

ISCOP2 (if the unit is a heat pump 

DDX–DOAS) must be based on the 

refrigerant yielding the lowest ISCOP2. 

A refrigerant is considered approved for 

use if it is listed on the nameplate of the 

single package unit or outdoor unit. 

Pursuant to the definition of ‘‘basic 

model’’ in § 431.92 of this chapter, 

specification of an additional refrigerant 

option that requires use of different 

hardware (i.e., compressors, heat 

exchangers, or air moving systems that 

are not the same or comparably 

performing), results in a different basic 

model. 

* * * * * 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36055 

■ 3. Amend § 429.70 by revising the 

tables in paragraphs (c)(2)(iv) and 

(c)(5)(vi)(B) to read as follows: 

§ 429.70 Alternative methods for 

determining energy efficiency and energy 

use. 

* * * * * 

(c) * * * 

(2) * * * 

(iv) * * * 

Validation class 

Minimum number of 

distinct models that 

must be tested per 

AEDM 

Air-Cooled, Split and Packaged Air Conditioners (ACs) and Heat Pumps (HPs) less than 65,000 Btu/h Cooling Capacity 

(3-Phase).

2 Basic Models. 

(A) Commercial HVAC Validation Classes 

Air-Cooled, Split and Packaged ACs and HPs greater than or equal to 65,000 Btu/h Cooling Capacity and Less than 

760,000 Btu/h Cooling Capacity.

2 Basic Models. 

Water-Cooled, Split and Packaged ACs and HPs, All Cooling Capacities ............................................................................ 2 Basic Models. 

Evaporatively-Cooled, Split and Packaged ACs and HPs, All Capacities .............................................................................. 2 Basic Models. 

Water-Source HPs, All Capacities ........................................................................................................................................... 2 Basic Models. 

Single Package Vertical ACs and HPs ................................................................................................................................... 2 Basic Models. 

Packaged Terminal ACs and HPs ........................................................................................................................................... 2 Basic Models. 

Air-Cooled, Variable Refrigerant Flow ACs and HPs .............................................................................................................. 2 Basic Models. 

Water-Cooled, Variable Refrigerant Flow ACs and HPs ........................................................................................................ 2 Basic Models. 

Computer Room Air Conditioners, Air Cooled ........................................................................................................................ 2 Basic Models. 

Computer Room Air Conditioners, Water-Cooled ................................................................................................................... 2 Basic Models. 

Dehumidifying Direct Expansion-Dedicated Outdoor Air Systems, Air-cooled or Air-source Heat Pump, Without Ventilation Energy Recovery Systems.2 Basic Models. 

Dehumidifying Direct Expansion-Dedicated Outdoor Air Systems, Air-cooled or Air-source Heat Pump, With Ventilation 

Energy Recovery Systems.

2 Basic Models. 

Dehumidifying Direct Expansion-Dedicated Outdoor Air Systems, Water-cooled, Water-source Heat Pump, or Ground 

Source Closed-loop Heat Pump, Without Ventilation Energy Recovery Systems.

2 Basic Models. 

Dehumidifying Direct Expansion-Dedicated Outdoor Air Systems, Water-cooled, Water-source Heat Pump, or Ground 

Source Closed-loop Heat Pump, With Ventilation Energy Recovery Systems.

2 Basic Models. 

(B) Commercial Water Heater Validation Classes 

Gas-fired Water Heaters and Hot Water Supply Boilers Less than 10 Gallons ..................................................................... 2 Basic Models. 

Gas-fired Water Heaters and Hot Water Supply Boilers Greater than or Equal to 10 Gallons ............................................. 2 Basic Models. 

Oil-fired Water Heaters and Hot Water Supply Boilers Less than 10 Gallons ....................................................................... 2 Basic Models. 

Oil-fired Water Heaters and Hot Water Supply Boilers Greater than or Equal to 10 Gallons ............................................... 2 Basic Models. 

Electric Water Heaters ............................................................................................................................................................. 2 Basic Models. 

Heat Pump Water Heaters ...................................................................................................................................................... 2 Basic Models. 

Unfired Hot Water Storage Tanks ........................................................................................................................................... 2 Basic Models. 

(C) Commercial Packaged Boilers Validation Classes 

Gas-fired, Hot Water Only Commercial Packaged Boilers ..................................................................................................... 2 Basic Models. 

Gas-fired, Steam Only Commercial Packaged Boilers ........................................................................................................... 2 Basic Models. 

Gas-fired Hot Water/Steam Commercial Packaged Boilers ................................................................................................... 2 Basic Models. 

Oil-fired, Hot Water Only Commercial Packaged Boilers ....................................................................................................... 2 Basic Models. 

Oil-fired, Steam Only Commercial Packaged Boilers ............................................................................................................. 2 Basic Models. 

Oil-fired Hot Water/Steam Commercial Packaged Boilers ...................................................................................................... 2 Basic Models. 

(D) Commercial Furnace Validation Classes 

Gas-fired Furnaces .................................................................................................................................................................. 2 Basic Models. 

Oil-fired Furnaces .................................................................................................................................................................... 2 Basic Models. 

(E) Commercial Refrigeration Equipment Validation Classes 1

Self-Contained Open Refrigerators ......................................................................................................................................... 2 Basic Models. 

Self-Contained Open Freezers ................................................................................................................................................ 2 Basic Models. 

Remote Condensing Open Refrigerators ................................................................................................................................ 2 Basic Models. 

Remote Condensing Open Freezers ....................................................................................................................................... 2 Basic Models. 

Self-Contained Closed Refrigerators ....................................................................................................................................... 2 Basic Models. 

Self-Contained Closed Freezers ............................................................................................................................................. 2 Basic Models. 

Remote Condensing Closed Refrigerators .............................................................................................................................. 2 Basic Models. 

Remote Condensing Closed Freezers .................................................................................................................................... 2 Basic Models. 

1The minimum number of tests indicated above must be comprised of a transparent model, a solid model, a vertical model, a semi-vertical 

model, a horizontal model, and a service-over-the counter model, as applicable based on the equipment offering. However, manufacturers do not 

need to include all types of these models if it will increase the minimum number of tests that need to be conducted. 

* * * * * (5) * * * (vi) * * * 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36056 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

(B) * * * 

Equipment Metric Applicable 

tolerance 

Commercial Packaged Boilers ..................................................................................... Combustion Efficiency ..............................

Thermal Efficiency ....................................

5% (0.05) 

5% (0.05) 

Commercial Water Heaters or Hot Water Supply Boilers ........................................... Thermal Efficiency .................................... 5% (0.05) 

Standby Loss ............................................ 10% (0.1) 

Unfired Storage Tanks ................................................................................................. R-Value ..................................................... 10% (0.1) 

Air-Cooled, Split and Packaged ACs and HPs less than 65,000 Btu/h Cooling Capacity (3-Phase).Seasonal Energy-Efficiency Ratio ............ 5% (0.05) 

Heating Season Performance Factor ....... 5% (0.05) 

Energy Efficiency Ratio ............................ 10% (0.1) 

Air-Cooled, Split and Packaged ACs and HPs greater than or equal to 65,000 Btu/h 

Cooling Capacity and Less than 760,000 Btu/h Cooling Capacity.

Energy Efficiency Ratio ............................ 5% (0.05) 

Coefficient of Performance ....................... 5% 

Integrated Energy Efficiency Ratio ........... 10% (0.1) 

Water-Cooled, Split and Packaged ACs and HPs, All Cooling Capacities ................. Energy Efficiency Ratio ............................ 5% (0.05) 

Coefficient of Performance ....................... 5% (0.05) 

Integrated Energy Efficiency Ratio ........... 10% (0.1) 

Evaporatively-Cooled, Split and Packaged ACs and HPs, All Capacities .................. Energy Efficiency Ratio ............................ 5% (0.05) 

Coefficient of Performance ....................... 5% (0.05) 

Integrated Energy Efficiency Ratio ........... 10% (0.1) 

Water-Source HPs, All Capacities ............................................................................... Energy Efficiency Ratio ............................ 5% (0.05) 

Coefficient of Performance ....................... 5% (0.05) 

Integrated Energy Efficiency Ratio ........... 10% (0.1) 

Single Package Vertical ACs and HPs ........................................................................ Energy Efficiency Ratio ............................ 5% (0.05) 

Coefficient of Performance ....................... 5% (0.05) 

Packaged Terminal ACs and HPs ............................................................................... Energy Efficiency Ratio ............................ 5% (0.05) 

Coefficient of Performance ....................... 5% (0.05) 

Variable Refrigerant Flow ACs and HPs ..................................................................... Energy Efficiency Ratio ............................ 5% (0.05) 

Coefficient of Performance ....................... 5% (0.05) 

Integrated Energy Efficiency Ratio ........... 10% (0.1) 

Computer Room Air Conditioners ................................................................................ Net Sensible Coefficient of Performance 5% (0.05) 

Dehumidifying Direct Expansion-Dedicated Outdoor Air Systems .............................. Integrated Seasonal Coefficient of Performance 2.10% (0.1) 

Integrated Seasonal Moisture Removal 

Efficiency 2.

10% (0.1) 

Commercial Warm-Air Furnaces .................................................................................. Thermal Efficiency .................................... 5% (0.05) 

Commercial Refrigeration Equipment .......................................................................... Daily Energy Consumption ....................... 5% (0.05) 

* * * * * 

PART 431—ENERGY EFFICIENCY 

PROGRAM FOR CERTAIN 

COMMERCIAL AND INDUSTRIAL 

EQUIPMENT 

■ 4. The authority citation for part 431 

continues to read as follows: 

Authority: 42 U.S.C. 6291–6317; 28 U.S.C. 

2461 note. 

■ 5. Amend § 431.2 by revising the 

definition of ‘‘Commercial HVAC & WH 

product’’ to read as follows: 

§ 431.2 Definitions. 

* * * * * 

Commercial HVAC & WH product 

means any small, large, or very large 

commercial package air-conditioning 

and heating equipment (as defined in 

§ 431.92), packaged terminal air 

conditioner (as defined in § 431.92), 

packaged terminal heat pump (as 

defined in § 431.92), single package 

vertical air conditioner (as defined in 

§ 431.92), single package vertical heat 

pump (as defined in § 431.92), computer 

room air conditioner (as defined in 

§ 431.92), variable refrigerant flow 

multi-split air conditioner (as defined in 

§ 431.92), variable refrigerant flow 

multi-split heat pump (as defined in 

§ 431.92), direct expansion-dedicated 

outdoor air system (as defined in 

§ 431.92), commercial packaged boiler 

(as defined in § 431.82), hot water 

supply boiler (as defined in § 431.102), 

commercial warm air furnace (as 

defined in § 431.72), instantaneous 

water heater (as defined in § 431.102), 

storage water heater (as defined in 

§ 431.102), or unfired hot water storage 

tank (as defined in § 431.102). 

* * * * * 

■ 6. Amend § 431.92 by: 

■ a. Revising the definition of ‘‘Basic 

model’’; and 

■ b. Adding, in alphabetical order, the 

definitions for ‘‘Dehumidifying direct 

expansion-dedicated outdoor air system, 

or DDX–DOAS,’’ ‘‘Direct expansiondedicated outdoor air system, or DX– 

DOAS,’’ ‘‘Integrated seasonal coefficient 

of performance 2, or ISCOP2,’’ 

‘‘Integrated seasonal moisture removal 

efficiency 2, or ISMRE2,’’ and 

‘‘Ventilation energy recovery system, or 

VERS’’. 

The revision and additions read as 

follows: 

§ 431.92 Definitions concerning 

commercial air conditioners and heat 

pumps. 

* * * * * 

Basic model includes: 

(1) Computer room air conditioners 

means all units manufactured by one 

manufacturer within a single equipment 

class, having the same primary energy 

source (e.g., electric or gas), and which 

have the same or comparably 

performing compressor(s), heat 

exchangers, and air moving system(s) 

that have a common ‘‘nominal’’ cooling 

capacity. 

(2) Dehumidifying direct expansiondedicated outdoor air system means all 

units manufactured by one 

manufacturer, having the same primary 

energy source (e.g., electric or gas), 

within a single equipment class; with 

the same or comparably performing 

compressor(s), heat exchangers, 

ventilation energy recovery system(s) (if 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36057 

present), and air moving system(s) that 

have a common ‘‘nominal’’ moisture 

removal capacity. 

(3) Packaged terminal air conditioner 

(PTAC) or packaged terminal heat 

pump (PTHP) means all units 

manufactured by one manufacturer 

within a single equipment class, having 

the same primary energy source (e.g., 

electric or gas), and which have the 

same or comparable compressors, same 

or comparable heat exchangers, and 

same or comparable air moving systems 

that have a cooling capacity within 300 

Btu/h of one another. 

(4) Single package vertical units 

means all units manufactured by one 

manufacturer within a single equipment 

class, having the same primary energy 

source (e.g., electric or gas), and which 

have the same or comparably 

performing compressor(s), heat 

exchangers, and air moving system(s) 

that have a rated cooling capacity 

within 1500 Btu/h of one another. 

(5) Small, large, and very large aircooled or water-cooled commercial 

package air conditioning and heating 

equipment means all units 

manufactured by one manufacturer 

within a single equipment class, having 

the same or comparably performing 

compressor(s), heat exchangers, and air 

moving system(s) that have a common 

‘‘nominal’’ cooling capacity. 

(6) Small, large, and very large water 

source heat pump means all units 

manufactured by one manufacturer 

within a single equipment class, having 

the same primary energy source (e.g., 

electric or gas), and which have the 

same or comparable compressors, same 

or comparable heat exchangers, and 

same or comparable ‘‘nominal’’ 

capacity. 

(7) Variable refrigerant flow systems 

means all units manufactured by one 

manufacturer within a single equipment 

class, having the same primary energy 

source (e.g., electric or gas), and which 

have the same or comparably 

performing compressor(s) that have a 

common ‘‘nominal’’ cooling capacity 

and the same heat rejection medium 

(e.g., air or water) (includes VRF water 

source heat pumps). 

* * * * * 

Dehumidifying direct expansiondedicated outdoor air system, or DDX– 

DOAS, means a direct expansiondedicated outdoor air system that is 

capable of dehumidifying air to a 55 °F 

dew point—when operating under 

Standard Rating Condition A as 

specified in Table 4 or Table 5 of AHRI 

920–2020 (incorporated by reference, 

see § 431.95) with a barometric pressure 

of 29.92 in Hg—for any part of the range 

of airflow rates advertised in 

manufacturer materials, and has a 

moisture removal capacity of less than 

324 lb/h. 

Direct expansion-dedicated outdoor 

air system, or DX–DOAS, means a 

category of small, large, or very large 

commercial package air-conditioning 

and heating equipment which is capable 

of providing ventilation and 

conditioning of 100-percent outdoor air 

or marketed in materials (including but 

not limited to, specification sheets, 

insert sheets, and online materials) as 

having such capability. 

* * * * * 

Integrated seasonal coefficient of 

performance 2, or ISCOP2, means a 

seasonal weighted-average heating 

efficiency for heat pump dedicated 

outdoor air systems, expressed in W/W, 

as measured according to appendix B of 

this subpart. 

Integrated seasonal moisture removal 

efficiency 2, or ISMRE2, means a 

seasonal weighted average 

dehumidification efficiency for 

dedicated outdoor air systems, 

expressed in lbs. of moisture/kWh, as 

measured according to appendix B of 

this subpart. 

* * * * * 

Ventilation energy recovery system, or 

VERS, means a system that preconditions outdoor ventilation air 

entering the equipment through direct 

or indirect thermal and/or moisture 

exchange with the exhaust air, which is 

defined as the building air being 

exhausted to the outside from the 

equipment. 

* * * * * 

■ 7. Section 431.95 is amended by: 

■ a. Revising paragraph (a) and the 

introductory text to paragraph (b); 

■ b. Redesignating paragraphs (b)(6) and 

(7) as (b)(8) and (9); 

■ c. Adding new paragraphs (b)(6) and 

(7); 

■ d. Revising the introductory text to 

paragraph (c) and paragraph (c)(2); 

■ e. Redesignating paragraphs (c)(3) and 

(4) as (c)(5) and (6); and 

■ f. Adding new paragraphs (c)(3) and 

(4), and paragraph (c)(7). 

The revisions and additions read as 

follows: 

§ 431.95 Materials incorporated by 

reference. 

(a) Certain material is incorporated by 

reference into this subpart with the 

approval of the Director of the Federal 

Register in accordance with 5 U.S.C. 

552(a) and 1 CFR part 51. To enforce 

any edition other than that specified in 

this section, DOE must publish a 

document in the Federal Register and 

the material must be available to the 

public. All approved material is 

available for inspection at the U.S. 

Department of Energy, Office of Energy 

Efficiency and Renewable Energy, 

Building Technologies Program, 6th 

Floor, 950 L’Enfant Plaza SW, 

Washington, DC 20024, (202) 586–1445, 

or go to: www.energy.gov/eere/ 

buildings/appliance-and-equipmentstandards-program, and may be 

obtained from the other sources in this 

section. It is also available for 

inspection at the National Archives and 

Records Administration (NARA). For 

information on the availability of this 

material at NARA, email: fedreg.legal@

nara.gov, or go to: www.archives.gov/ 

federal-register/cfr/ibr-locations.html. 

(b) AHRI. Air-Conditioning, Heating, 

and Refrigeration Institute, 2311 Wilson 

Blvd., Suite 400, Arlington, VA 22201, 

(703) 524–8800, or go to: 

www.ahrinet.org. 

* * * * * 

(6) AHRI Standard 920–2020 (I–P), 

(‘‘AHRI 920–2020’’), ‘‘2020 Standard for 

Performance Rating of DX-Dedicated 

Outdoor Air System Units,’’ approved 

February 4, 2020, IBR approved for 

appendix B to this subpart. 

(7) AHRI Standard 1060–2018, 

(‘‘ANSI/AHRI 1060–2018’’), ‘‘2018 

Standard for Performance Rating of Airto-Air Exchangers for Energy Recovery 

Ventilation Equipment,’’ approved 

2018, (ANSI/AHRI 1060–2018), IBR 

approved for appendix B to this subpart. 

(c) ASHRAE. American Society of 

Heating, Refrigerating and AirConditioning Engineers, 180 

Technology Parkway, Peachtree 

Corners, Georgia 30092, (404) 636–8400, 

or go to: www.ashrae.org. 

* * * * * 

(2) ANSI/ASHRAE Standard 37–2009, 

(‘‘ANSI/ASHRAE 37’’ or ‘‘ANSI/ 

ASHRAE 37–2009’’), ‘‘Methods of 

Testing for Rating Electrically Driven 

Unitary Air-Conditioning and Heat 

Pump Equipment,’’ ASHRAE approved 

June 24, 2009, IBR approved for § 431.96 

and appendices A and B to this subpart. 

(3) ANSI/ASHRAE Standard 41.1– 

2013, (‘‘ANSI/ASHRAE 41.1–2013’’), 

‘‘Standard Method for Temperature 

Measurement,’’ ANSI approved January 

30, 2013, IBR approved for appendix B 

to this subpart. 

(4) ANSI/ASHRAE Standard 41.6– 

2014, (‘‘ANSI/ASHRAE 41.6–2014’’), 

‘‘Standard Method for Humidity 

Measurement,’’ ANSI approved July 3, 

2014, IBR approved for appendix B to 

this subpart. 

* * * * * 

(7) ANSI/ASHRAE Standard 198– 

2013, (‘‘ANSI/ASHRAE 198–2013’’), 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36058 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

‘‘Method of Test for Rating DXDedicated Outdoor Air Systems for 

Moisture Removal Capacity and 

Moisture Removal Efficiency,’’ 

approved by ANSI on January 30, 2013, 

IBR approved for appendix B to this 

subpart. 

* * * * * 

■ 8. Amend § 431.96 by: 

■ a. Revising paragraph (a) and Table 1 

in paragraph (b)(2); and 

■ b. Designating the table in paragraph 

(d) as Table 2 to paragraph (d). 

The revisions read as follows: 

§ 431.96 Uniform test method for the 

measurement of energy efficiency of 

commercial air conditioners and heat 

pumps. 

(a) Scope. This section contains test 

procedures for measuring, pursuant to 

EPCA, the energy efficiency of any 

small, large, or very large commercial 

package air-conditioning and heating 

equipment, packaged terminal air 

conditioners and packaged terminal 

heat pumps, computer room air 

conditioners, variable refrigerant flow 

systems, single package vertical air 

conditioners and single package vertical 

heat pumps, and dehumidifying direct 

expansion-dedicated outdoor air 

systems. 

(b) * * * 

(2) * * * 

TABLE 1 TO PARAGRAPH (b)—TEST PROCEDURES FOR COMMERCIAL AIR CONDITIONERS AND HEAT PUMPS

Equipment type Category 

Cooling capacity or 

moisture removal 

capacity 

Energy efficiency 

descriptor 

Use tests, conditions, 

and procedures 1 in 

Additional test 

procedure provisions 

as indicated in the 

listed paragraphs of 

this section 

Small Commercial 

Package Air-Conditioning and Heating 

Equipment.

Air-Cooled, 3-Phase, 

AC and HP.

<65,000 Btu/h ........... SEER and HSPF ...... AHRI 210/240–2008 

(omit section 6.5).

Paragraphs (c) and 

(e). 

Air-Cooled AC and 

HP.

≥65,000 Btu/h and 

<135,000 Btu/h.

EER, IEER, and COP Appendix A to this 

subpart.

None. 

Water-Cooled and 

EvaporativelyCooled AC.

<65,000 Btu/h ........... EER ........................... AHRI 210/240–2008 

(omit section 6.5).

Paragraphs (c) and 

(e). 

≥65,000 Btu/h and 

<135,000 Btu/h.

EER ........................... AHRI 340/360–2007 

(omit section 6.3).

Paragraphs (c) and 

(e). 

Water-Source HP ...... <135,000 Btu/h ......... EER and COP .......... ISO Standard 13256– 

1 (1998).

Paragraph (e). 

Large Commercial 

Package Air-Conditioning and Heating 

Equipment.

Air-Cooled AC and 

HP.

≥135,000 Btu/h and 

<240,000 Btu/h.

EER, IEER and COP Appendix A to this 

subpart.

None. 

Water-Cooled and 

EvaporativelyCooled AC.

≥135,000 Btu/h and 

<240,000 Btu/h.

EER ........................... AHRI 340/360–2007 

(omit section 6.3).

Paragraphs (c) and 

(e). 

Very Large Commercial Package AirConditioning and 

Heating Equipment.

Air-Cooled AC and 

HP.

≥240,000 Btu/h and 

<760,000 Btu/h.

EER, IEER and COP Appendix A to this 

subpart.

None. 

Water-Cooled and 

EvaporativelyCooled AC.

≥240,000 Btu/h and 

<760,000 Btu/h.

EER ........................... AHRI 340/360–2007 

(omit section 6.3).

Paragraphs (c) and 

(e). 

Packaged Terminal Air 

Conditioners and 

Heat Pumps.

AC and HP ................ <760,000 Btu/h ......... EER and COP .......... Paragraph (g) of this 

section.

Paragraphs (c), (e), 

and (g). 

Computer Room Air 

Conditioners.

AC ............................. <65,000 Btu/h ........... SCOP ........................ ASHRAE 127–2007 

(omit section 5.11).

Paragraphs (c) and 

(e). 

≥65,000 Btu/h and 

<760,000 Btu/h.

SCOP ........................ ASHRAE 127–2007 

(omit section 5.11).

Paragraphs (c) and 

(e). 

Variable Refrigerant 

Flow Multi-split Systems.

AC ............................. <65,000 Btu/h (3- 

phase).

SEER ........................ AHRI 1230–2010 

(omit sections 5.1.2 

and 6.6).

Paragraphs (c), (d), 

(e), and (f). 

≥65,000 Btu/h and 

<760,000 Btu/h.

EER ........................... AHRI 1230–2010 

(omit sections 5.1.2 

and 6.6).

Paragraphs (c), (d), 

(e), and (f). 

Variable Refrigerant 

Flow Multi-split Systems, Air-cooled.

HP ............................. <65,000 Btu/h (3- 

phase).

SEER and HSPF ...... AHRI 1230–2010 

(omit sections 5.1.2 

and 6.6).

Paragraphs (c), (d), 

(e), and (f). 

≥65,000 Btu/h and 

<760,000 Btu/h.

EER and COP .......... AHRI 1230–2010 

(omit sections 5.1.2 

and 6.6).

Paragraphs (c), (d), 

(e), and (f). 

Variable Refrigerant 

Flow Multi-split Systems, Water-source.

HP ............................. <760,000 Btu/h ......... EER and COP .......... AHRI 1230–2010 

(omit sections 5.1.2 

and 6.6).

Paragraphs (c), (d), 

(e), and (f). 

Single Package 

Vertical Air Conditioners and Single 

Package Vertical 

Heat Pumps.

AC and HP ................ <760,000 Btu/h ......... EER and COP .......... AHRI 390–2003 (omit 

section 6.4).

Paragraphs (c) and 

(e). 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 36059 

TABLE 1 TO PARAGRAPH (b)—TEST PROCEDURES FOR COMMERCIAL AIR CONDITIONERS AND HEAT PUMPS—Continued 

Equipment type Category 

Cooling capacity or 

moisture removal 

capacity 

Energy efficiency 

descriptor 

Use tests, conditions, 

and procedures 1 in 

Additional test 

procedure provisions 

as indicated in the 

listed paragraphs of 

this section 

Dehumidifying Direct 

Expansion-Dedicated Outdoor Air 

Systems.

All .............................. <324 lbs. of moisture 

removal/hr.

ISMRE2 and ISCOP2 Appendix B of this 

subpart.

None. 

1 Incorporated by reference; see § 431.95. 

2 Moisture removal capacity is determined according to appendix B of this subpart. 

* * * * * 

■ 9. Add Appendix B to subpart F of 

part 431 to read as follows: 

Appendix B to Subpart F of Part 431— 

Uniform Test Method for Measuring the 

Energy Consumption of Dehumidifying 

Direct Expansion-Dedicated Outdoor 

Air Systems 

Note: Beginning [date 360 days after 

publication of a test procedure final rule], 

representations with respect to energy use or 

efficiency of dehumidifying direct 

expansion-dedicated outdoor air systems 

must be based on testing conducted in 

accordance with this appendix. 

Manufacturers may elect to use this appendix 

early. 

1. Referenced materials. 

1.1. Incorporation by reference. 

DOE incorporated by reference in § 431.95, 

the entire standard for AHRI 920–2020, 

ANSI/AHRI 1060–2018; ANSI/ASHRAE 37– 

2009, ANSI/ASHRAE 41.1–2013, ANSI/ 

ASHRAE 41.6–2014, and ANSI/ASHRAE 

198–2013. However, only enumerated 

provisions of AHRI 920–2020, ANSI/ 

ASHRAE 37–2009, ANSI/ASHRAE 41.6– 

2014, and ANSI/ASHRAE 198–2013, as set 

forth in paragraphs (a) through (d) of this 

section are applicable. To the extent there is 

a conflict between the terms or provisions of 

a referenced industry standard and the CFR, 

the CFR provisions control. 

(a) AHRI 920–2020: 

(i) Section 3—Definitions, as specified in 

section 2.2.1(a) of this appendix; 

(ii) Section 5—Test Requirements, as 

specified in section 2.2.1(b) of this appendix; 

(iii) Section 6—Rating Requirements, as 

specified in section 2.2.1(c) of this appendix, 

omitting section 6.1.2 (but retaining sections 

6.1.2.1–6.1.2.8) and 6.6.1; 

(iv) Section 11—Symbols and Subscripts, 

as specified in section 2.2.1(d) of this 

appendix; 

(v) Appendix A—References—Normative, 

as specified in section 2.2.1(e) of this 

appendix; 

(vi) Appendix C—ANSI/ASHRAE Standard 

198 and ANSI/ASHRAE Standard 37 

Additions, Clarifications and Exceptions— 

Normative, as specified in section 2.2.1(f) of 

this appendix, and 

(vii) Appendix F—Unit Configuration for 

Standard Efficiency Determination— 

Normative, as specified in section 2.2.1(g) of 

this appendix. 

(b) ANSI/ASHRAE 37–2009: 

(i) Section 5.1—Temperature Measuring 

Instruments (excluding sections 5.1.1 and 

5.1.2), as specified in sections 2.2.1(b) and (f) 

of this appendix; 

(ii) Section 5.2—Refrigerant, Liquid, and 

Barometric Pressure Measuring Instruments, 

as specified in section 2.2.1(b) of this 

appendix; 

(iii) Sections 5.3—Air Differential Pressure 

and Airflow Measurements, as specified in 

section 2.2.1(b) of this appendix; 

(iv) Sections 5.5(b)—Volatile Refrigerant 

Measurement, as specified in section 2.2.1(b) 

of this appendix; 

(v) Section 6.1—Enthalpy Apparatus 

(excluding 6.1.1 and 6.1.3 through 6.1.6), as 

specified in section 2.2.1(b) of this appendix; 

(vi) Section 6.2—Nozzle Airflow 

Measuring Apparatus, as specified in section 

2.2.1(b) of this appendix; 

(vii) Section 6.3—Nozzles, as specified in 

section 2.2.1(b) of this appendix; 

(viii) Section 6.4—External Static Pressure 

Measurements, as specified in section 

2.2.1(b) of this appendix; 

(ix) Section 6.5—Recommended Practices 

for Static Pressure Measurements, as 

specified in section 2.2.1(f) of this appendix; 

(x) Section 7.3—Indoor and Outdoor Air 

Enthalpy Methods, as specified in section 

2.2.1(f) of this appendix; 

(xi) Section 7.4—Compressor Calibration 

Method, as specified in section 2.2.1(f) of this 

appendix; 

(xii) Section 7.5—Refrigerant Enthalpy 

Method, as specified in section 2.2.1(f) of this 

appendix; 

(xiii) Section 7.6—Outdoor Liquid Coil 

Method, as specified in section 2.2.1(f) of this 

appendix; 

(xiv) Section 7.7—Airflow Rate 

Measurement (excluding sections 7.7.1.2, 

7.7.3, and 7.7.4), as specified in section 

2.2.1(b) of this appendix; 

(xv) Table 1—Applicable Test Methods, as 

specified in section 2.2.1(f) of this appendix; 

(xvi) Section 8.6—Additional 

Requirements for the Outdoor Air Enthalpy 

Method, as specified in section 2.2.1(f) of this 

appendix; 

(xvii) Table 2b—Test Tolerances (I–P 

Units), as specified in sections 2.2.1(c) and 

2.2(f) of this appendix; and 

(xviii) Errata sheet issued on October 3, 

2016, as specified in section 2.2.1(f) of this 

appendix. 

(c) ANSI/ASHRAE 41.6–2014: 

(i) Section 4—Classifications, as specified 

in section 2.2.1(f) of this appendix; 

(ii) Section 5—Requirements, as specified 

in section 2.2.1(f) of this appendix; 

(iii) Section 6—Instruments and 

Calibration, as specified in section 2.2.1(f) of 

this appendix; 

(iv) Section 7.1—Standard Method Using 

the Cooled-Surface Condensation Hygrometer 

as specified in section 2.2.1(f) of this 

appendix; and 

(v) Section 7.4—Electronic and Other 

Humidity Instruments. as specified in section 

2.2.1(f) of this appendix. 

(d) ANSI/ASHRAE 198–2013: 

(i) Section 4.4—Temperature Measuring 

Instrument, as specified in section 2.2.1(b) of 

this appendix; 

(ii) Section 4.5—Electrical Instruments, as 

specified in section 2.2.1(b) of this appendix; 

(iii) Section 4.6—Liquid Flow 

Measurement, as specified in section 2.2.1(b) 

of this appendix; 

(iv) Section 4.7—Time and Mass 

Measurements, as specified in section 

2.2.1(b) of this appendix; 

(v) Section 6.1—Test Room Requirements, 

as specified in section 2.2.1(b) of this 

appendix; 

(vi) Section 6.6—Unit Preparation, as 

specified in section 2.2.1(b) of this appendix; 

(vii) Section 7.1—Preparation of the Test 

Room(s), as specified in section 2.2.1(b) of 

this appendix; 

(viii) Section 7.2—Equipment Installation, 

as specified in section 2.2.1(b) of this 

appendix; 

(ix) Section 8.2—Equilibrium, as specified 

in section 2.2.1(b) of this appendix, and 

(x) Section 8.4—Test Duration and 

Measurement Frequency, as specified in 

section 2.2.1(b) of this appendix. 

1.2. Informational materials. 

DOE refers to the following provision of 

AHRI 920–2020, for informational purposes 

only: 

(a) Appendix E—Typical Test Unit 

Installations—Informative, as specified in 

section 2.2.1(g) of this appendix. 

(b) Reserved. 

2. Test Method. 

2.1. Capacity. 

Moisture removal capacity (in pounds per 

hour) and supply airflow rate (in standard 

cubic feet per minute) are determined 

according to AHRI 920–2020 (incorporated 

by reference; see § 431.95) as specified in 

section 2.2 of this appendix. 

2.2. Efficiency. 

2.2.1. Determine the ISMRE2 for all DDX– 

DOASes and the ISCOP2 for all heat pump 


khammond on DSKJM1Z7X2PROD with PROPOSALS3
36060 Federal Register / Vol. 86, No. 127 / Wednesday, July 7, 2021 / Proposed Rules 

DDX–DOASes in accordance with the 

following sections of AHRI 920–2020. 

(a) Section 3—Definitions, including the 

references to ANSI/AHRI 1060–2018 

(incorporated by reference; see § 431.95); 

(i) Non-standard Low-static Fan Motor. A 

supply fan motor that cannot maintain 

external static pressure as high as specified 

in Table 7 of AHRI 920–2020 when operating 

at a manufacturer-specified airflow rate and 

that is distributed in commerce as part of an 

individual model within the same basic 

model of a DDX–DOAS that is distributed in 

commerce with a different motor specified 

for testing that can maintain the required 

external static pressure. 

(b) Section 5—Test Requirements, 

including the references to sections 5.1, 5.2, 

5.3, 5.5, 6.1, 6.2, 6.3, 6.4, and 7.7 (not 

including sections 7.7.1.2, 7.7.3, and 7.7.4) of 

ANSI/ASHRAE 37–2009 (incorporated by 

reference; see § 431.95), and sections 4.4, 4.5, 

4.6, 4.7, 5.1, 6.1, 6.6, 7.1, 7.2, 8.2, and 8.4 of 

ANSI/ASHRAE 198–2013 (incorporated by 

reference; see § 431.95); 

(i) All control settings are to remain 

unchanged for all Standard Rating 

Conditions once system set up has been 

completed, except as explicitly allowed or 

required by AHRI 920–2020 or as indicated 

in the supplementary test instructions (STI). 

Component operation shall be controlled by 

the unit under test once the provisions in 

section 2.2.1(c) of this appendix are met. 

(c) Section 6—Rating Requirements 

(omitting sections 6.1.2 and 6.6.1), including 

the references to Table 2b of ANSI/ASHRAE 

37–2009, and ANSI/ASHRAE 198–2013. 

(i) For water-cooled DDX–DOASes, the 

‘‘Condenser Water Entering Temperature, 

Cooling Tower Water’’ conditions specified 

in Table 4 of AHRI 920–2020 shall be used. 

For water-source heat pump DDX–DOASes, 

the ‘‘Water-Source Heat Pumps’’ conditions 

specified in Table 5 of AHRI 920–2020 shall 

be used. 

(ii) For water-cooled or water-source DDX– 

DOASes with integral pumps, set the external 

head pressure to 20 ft. of water column, with 

a ¥0/+1 ft. condition tolerance and a 1 ft. 

operating tolerance. 

(iii) When using the degradation coefficient 

method as specified in section 6.9.2 of AHRI 

920–2020, Equation 20 applies to DDX– 

DOAS without VERS, with deactivated VERS 

(see section 5.4.3 of AHRI 920–2020), or 

sensible-only VERS tested under Standard 

Rating Conditions other than D. 

(iv) Rounding requirements for 

representations are to be followed as stated 

in sections 6.1.2.1 through 6.1.2.8 of AHRI 

920–2020; 

(d) Section 11—Symbols and Subscripts, 

including references to ANSI/ASHRAE 1060– 

2018; 

(e) Appendix A—References—Normative; 

(f) Appendix C—ANSI/ASHRAE 198–2013 

and ANSI/ASHRAE 37 Additions, 

Clarifications and Exceptions—Normative, 

including references to sections 5.1, 6.5, 7.3, 

7.4, 7.5, 7.6, 8.6, Table 1, Table 2b, and the 

errata sheet of ANSI/ASHRAE 37–2009, 

ANSI/ASHRAE 41.1–2013 (incorporated by 

reference; see § 431.95), sections 4, 5, 6, 7.1, 

and 7.4 of ANSI/ASHRAE 41.6–2014 

(incorporated by reference; see § 431.95), and 

ANSI/ASHRAE 1060–2018; 

(g) Appendix E—Typical Test Unit 

Installations—Informative, for information 

only; 

(h) Appendix F—Unit Configuration for 

Standard Efficiency Determination— 

Normative. 

2.2.2. Optional Representations. Test 

provisions for the determination of the 

metrics indicated in paragraphs (a) through 

(d) of this section are optional and are 

determined according to the applicable 

provisions in section 2.2.1 of this appendix. 

For water-cooled DDX–DOASes, these 

optional representations may be determined 

using either the ‘‘Condenser Water Entering 

Temperature, Cooling Tower’’ or the 

‘‘Condenser Water Entering Temperature, 

Chilled Water’’ conditions specified in Table 

4 of AHRI 920–2020. For water-source heat 

pump DDX–DOASes, these optional 

representations may be determined using 

either the ‘‘Water-Source Heat Pumps’’ or 

‘‘Water-Source Heat Pump, Ground-Source 

Closed Loop’’ conditions specified in Table 

5 of AHRI 920–2020. The following metrics 

in AHRI 920–2020 are optional: 

(a) ISMRE70; 

(b) COPFull,x: 

(c) COPDOAS,x: and 

(d) ISMRE2 and ISCOP2 for water-cooled 

DDX–DOASes using the ‘‘Condenser Water 

Entering Temperature, Chilled Water’’ 

conditions specified in Table 4 of AHRI 920– 

2020 and for water-source heat pump DDX– 

DOASes using the ‘‘Water-Source Heat 

Pump, Ground-Source Closed Loop’’ 

conditions specified in Table 5 of AHRI 920– 

2020. 

2.3. Synonymous terms. 

(a) Any references to Dedicated Outdoor 

Air System Unit (DOAS Unit), Dedicated 

Outdoor Air System (DOAS), and Direct 

Expansion Dedicated Outdoor Air System 

(DX–DOAS) in AHRI 920–2020 and ANSI/ 

ASHRAE 198–2013 shall be considered 

synonymous with Dehumidifying Direct 

Expansion-Dedicated Outdoor Air System 

(DDX–DOAS) as defined in § 431.92. 

(b) Any references to energy recovery or 

energy recovery ventilator (ERV) in AHRI 

920–2020 and ANSI/ASHRAE 198–2013 

shall be considered synonymous with 

ventilation energy recovery system (VERS) as 

defined in § 431.92. 

[FR Doc. 2021–13773 Filed 7–6–21; 8:45 am] 

BILLING CODE 6450–01–P 


khammond on DSKJM1Z7X2PROD with PROPOSALS3