Energy Conservation Program: Test Procedures for Compressors

Federal RegisterJan 4, 2017

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[Docket No. EERE-2014-BT-TP-0054]

RIN 1904-AD43

Energy Conservation Program: Test Procedures for Compressors

AGENCY:

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

ACTION:

Final rule.

SUMMARY:

On May 5, 2016, the U.S. Department of Energy (DOE) published a notice of proposed rulemaking (NOPR) to establish new test procedures for certain varieties of compressors. That proposed rulemaking serves as the basis for the final rule. This final rule establishes definitions, materials incorporated by reference, sampling plans, representations requirements, enforcement provisions, and test procedures for certain varieties of compressors. Specifically, this final rule establishes full-load package isentropic efficiency as the applicable energy metric for certain fixed-speed compressors and part-load package isentropic efficiency as the applicable energy metric for certain variable-speed compressors. Finally, this final rule incorporates by reference certain sections of the ISO Standard 1217:2009(E), (ISO 1217:2009(E)), “Displacement compressors—Acceptance tests,” as amended through Amendment 1:2016, as the basis for a test method for determining compressor efficiency. ISO 1217:2009(E) includes a test method for measuring compressor inlet and discharge pressures, actual volume flow rate, electrical input power, package isentropic efficiency, and other compressor performance metrics. This final rule also adopts certain modifications and additions to ISO 1217:2009(E) to increase the specificity of certain testing methods established in ISO 1217:2009(E) and improve the repeatability of tested and measured values.

DATES:

The effective date of this rule is February 3, 2017. The final rule changes will be mandatory for representations starting July 3, 2017. The incorporation by reference of certain publications listed in the rule is approved by the Director of the Federal Register February 3, 2017.

ADDRESSES:

The docket, which includes

Federal Register

, public meeting attendee lists and transcripts, comments, and other supporting documents/materials, is available for review at

www.regulations.gov.

All documents in the docket are listed in the

www.regulations.gov

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

A link to the docket Web page can be found at

https://www1.eere.energy.gov/buildings/appliance_standards/product.aspx/productid/78.

The docket Web page contains simple instructions on how to access all documents, including public comments, in the docket.

FOR FURTHER INFORMATION CONTACT:

Mr. James Raba, 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) 586-8654. Email:

ApplianceStandardsQuestions@ee.doe.gov.

SUPPLEMENTARY INFORMATION:

This final rule incorporates by reference into 10 CFR part 431 the testing methods contained in the following commercial standards:

ISO 1217:2009(E), “Displacement compressors—Acceptance tests,” July 1, 2009, sections 2, 3, and 4; sections 5.2, 5.3, 5.4, 5.6, 5.9; paragraphs 6.2(g), and 6.2(h) including Table 1; Annex C (excluding C.1.2, C.2.1, C.3, C.4.2.2, C.4.3.1, and C.4.5). ISO 1217:2009/Amd.1:2016(E), Displacement compressors—Acceptance tests (Fourth edition); Amendment 1: “Calculation of isentropic efficiency and relationship with specific energy,” April 15, 2016, sections 3.5.1 and 3.6.1; sections H.2 and H.3 of Annex H.

Copies of ISO 1217:2009(E) and of ISO 1217:2009/Amendment 1:2016(E) may be purchased from ISO at Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland +41 22 749 01 11, or by going to

www.iso.org.

See section IV.N for additional information about ISO 1217:2009(E) and ISO 1217:2009/Amendment 1:2016(E).

Table of Contents

I. Authority and Background

A. Authority

B. Regulatory History for Compressors

II. Synopsis of the Final Rule

III. Discussion

A. Definitions

1. Definition of Covered Equipment

2. Air Compressor

3. Air Compressor Components

4. Rotary and Reciprocating Compressors

5. Brushless Electric Motor

6. Compressor Motor Nominal Horsepower

7. Volume Flow Rates

8. Maximum Full-Flow Operating Pressure

9. Lubricated Compressor

B. Scope of Applicability of the Test Procedure

1. Air Compressor Limitation

2. Rotary and Reciprocating Compressors

3. Driver Style

4. Compressor Capacity

5. Lubricant Presence

6. Specialty-Purpose Compressors

C. Metrics

1. Package Isentropic Efficiency

2. Package Specific Power

3. Power Factor

D. Incorporation by Reference of Industry Standard(s)

1. ISO 1217:2009(E)/Amd.1:2016

2. Comments Related to the incorporation of ISO 1217:2009(E)

E. Test Method

1. Measurement Equipment

2. Test Conditions

3. Equipment Configuration

4. Data Collection and Analysis

5. Determination of Full-Load and Part-Load Package Isentropic Efficiency

6. Allowable Deviation from Specified Load Points

7. Determination of Package Specific Power

8. Determination of Pressure Ratio at Full-Load Operating Pressure

9. Maximum Full-Flow Operating Pressure, Full-Load Operating Pressure, and Full-Load Actual Volume Flow Rate

F. Definition of Basic Model

G. Sampling Plan for Testing and Alternative Efficiency Determination Methods

1. Sampling Plan and Representations

2. Alternative Efficiency Determination Method

H. Enforcement Provisions

1. Sample Variability for Package Isentropic Efficiency

2. Full-Load Operating Pressure and Actual Volume Flow Rate

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866

B. Review Under the Regulatory Flexibility Act

1. Description and Estimate of the Number of Small Entities Affected

2. Discussion of Testing Burden and Comments

C. Review Under the Paperwork Reduction Act of 1995

D. Review Under the National Environmental Policy Act of 1969

E. Review Under Executive Order 13132

F. Review Under Executive Order 12988

G. Review Under the Unfunded Mandates Reform Act of 1995

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

I. Review Under Executive Order 12630

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

K. Review Under Executive Order 13211

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

M. Congressional Notification

N. Description of Materials Incorporated by Reference

V. Approval of the Office of the Secretary

I. Authority and Background

A. Authority

Title III of the Energy Policy and Conservation Act of 1975, as amended, (42 U.S.C. 6291,

et seq.

; “EPCA” or, “the Act”) sets forth a variety of provisions designed to improve energy efficiency.

Part C of Title III, which for editorial reasons was codified as Part A-1 upon incorporation into the U.S. Code (42 U.S.C. 6311-6317), establishes the Energy Conservation Program for Certain Industrial Equipment. Under EPCA, DOE may include a type of industrial equipment, including compressors, as covered equipment if it determines that to do so is necessary to carry out the purposes of Part A-1. (42 U.S. 6311(1)(L), 6311(2)(B)(i), and 6312(b)). The purpose of Part A-1 is to improve the efficiency of electric motors and pumps and certain other industrial equipment in order to conserve the energy resources of the Nation. (42 U.S.C. 6312(a))

All references to EPCA in this document refer to the statute as amended through the Energy Efficiency Improvement Act of 2015, Public Law 114-11 (Apr. 30, 2015).

Pursuant to EPCA, DOE's energy conservation program for covered equipment consists essentially of four parts: (1) Testing; (2) labeling; (3) Federal energy conservation standards; and (4) certification and enforcement procedures. Specifically, subject to certain criteria and conditions, EPCA requires DOE to develop test procedures to measure the energy efficiency, energy use, or estimated annual operating cost of each type of covered equipment. (42 U.S.C. 6314(a)) Manufacturers of covered equipment must use the prescribed DOE test procedures: (1) As the basis for certifying to DOE that their equipment complies with the applicable energy conservation standards adopted under EPCA (42 U.S.C. 6295(s) and 6316(a)) and (2) when making representations to the public regarding the energy use or efficiency of those equipment. (42 U.S.C. 6314(d))

B. Regulatory History for Compressors

Currently, no Federal energy conservation standards for compressors exist. Before today, no Federal test procedures for compressors existed.

On December 31, 2012, DOE published a Proposed Determination of Coverage (2012 NOPD) proposing to determine that compressors qualify as covered equipment under part A-1 of Title III of EPCA, as amended (42 U.S.C. 6311

et seq.

). DOE proposed that coverage was necessary for the purposes of Part A-1 on the basis that (1) DOE may prescribe energy conservation standards only for covered equipment; and (2) energy conservation standards for compressors would improve the efficiency of such equipment more than would be likely to occur in the absence of standards.77 FR 76972 (Dec. 31, 2012). On February 7, 2013, DOE published a notice reopening the comment period on the 2012 NOPD. 78 FR 8998.

On November 15, 2016, DOE published a final rule, which determined that coverage for compressors is necessary to carry out the purposes of Part A-1 of Title III of EPCA (herein referred to as “notice of final determination”). 81 FR 79991.

On February 5, 2014, DOE published in the

Federal Register

a notice of public meeting, and provided a framework document that addressed potential standards and test procedures rulemakings for these products. 79 FR 6839. DOE held a public meeting to discuss the framework document on April 1, 2014. At this meeting, DOE discussed and received comments on the framework document, which covered the analytical framework, models, and tools that DOE used to evaluate potential standards; and all other issues raised relevant to the development of energy conservation standards for the different categories of compressors. On March 18, 2014, DOE extended the comment period. 79 FR 15061.

On May 5, 2016, DOE published a NOPR, to propose test procedures for certain compressors (“May 2016 test procedure NOPR” or “test procedure NOPR”). 87 FR 27220. The test procedure NOPR proposed establishing a new subpart T of title 10 of the Code of Federal Regulations, part 431 (10 CFR part 431), which would contain definitions, materials incorporated by reference, and test procedures for determining the energy efficiency of certain varieties of compressors. The test procedure NOPR would also amend title 10 CFR part 429 to establish sampling plans, representations requirements, and enforcement provisions for certain compressors. On June 20, 2016, DOE held a public meeting to discuss the test procedure NOPR and receive comments from interested parties.

Finally, in this final rule, DOE responds to comments received from interested parties in response to the proposals presented in the May 2016 test procedure NOPR, either during the June 2016 NOPR public meeting or in subsequent written comments.

In response to the May 2016 test procedure NOPR, DOE received 17 written comments in addition to the verbal comments made by interested parties during the June 2016 NOPR public meeting. The commenters included: the Appliance Standards Awareness Project (ASAP); Atlas Copco AB (Atlas Copco); CASTAIR; the Compressed Air & Gas Institute (CAGI); Compressed Air Systems; Ingersoll Rand; Jenny Products; Kaeser Compressors; the Northwest Energy Efficiency Alliance (NEEA); the Pacific Gas and Electric Company (PG&E), San Diego Gas and Electric (SDG&E), Southern California Edison (SCE), and Southern California Gas Company (SCGC), collectively referred to as the California Investor Owned Utilities (CA IOUs); the People's Republic of China (P. R. China); Scales Industrial Technologies; Sullair; Saylor-Beall Manufacturing Company and Sullivan-Palatek, collectively referred to as Sullivan-Palatek. DOE identifies comments received in response to the May 2016 test procedure NOPR by the commenter, the number of document as listed in the docket maintained at

www.regulations.gov

(Docket No. EERE-2014-BT-TP-0054), and the page number of that document where the comment appears (for example: CAGI, No. 10 at p. 4). If a comment was made verbally during the NOPR public meeting, DOE also specifically identifies those as being located in the NOPR public meeting transcript (for example: CAGI, public meeting transcript, No. 16 at p. 100). This final rule also contains certain relevant comments that were submitted in response to the compressors energy conservation standards rulemaking and the 2012 NOPD, but pertain to the topics discussed in the test procedure rulemaking. Those comments are identified with the appropriate docket numbers, EERE-2013-BT-STD-0040 and EERE-2012-BT-DET-0033, respectively.

DOE notes that certain comments pertaining to the definition of “compressors” were addressed in the November 2016 notice of final determination. 81 FR 79991, 79992-4 (Nov. 15, 2016).

II. Synopsis of the Final Rule

In this final rule, DOE amends subpart T of title 10 of the Code of Federal Regulations, part 431 (10 CFR part 431), which contains definitions, materials incorporated by reference, and test procedures for determining the energy efficiency of certain varieties of compressors.

While the range of equipment included in DOE's definition of compressor is broad, the test procedures established by this rulemaking are limited to only a specific subset of

compressors. Specifically, this final rule applies only to a subset of rotary compressors, as defined in section III.B of this final rule. DOE intends this test procedure final rule to apply to similar equipment for which DOE is considering adopting energy conservation standards (Docket No. EERE-2014-BT-TP-0054). However, the scope of any energy conservation standards would be established in that rulemaking.

This final rule establishes package isentropic efficiency as the applicable energy metric for compressors within the scope of the final rule. Package isentropic efficiency describes the ratio of the ideal isentropic power required for compression to the actual packaged compressor power input used for the same compression process. Specifically, this final rule establishes two varieties of package isentropic efficiency, depending on equipment configuration: (1) Full-load package isentropic efficiency for certain fixed-speed compressors, and (2) part-load package isentropic efficiency for certain variable-speed compressors. In this final rule, DOE concludes these metrics provide a representative measurement of the energy performance of the rated compressor under an average cycle of use.

In this final rule, DOE establishes test methods to measure the inlet and discharge pressures, actual volume flow rate, and packaged compressor power input, as well as calculations of the theoretical power necessary for compression—all of which are required to calculate full- or part-load package isentropic efficiency. For reproducible and uniform measurement of these values, DOE incorporates by reference the test methods established in certain applicable sections of ISO 1217:2009(E), “Displacement compressors—Acceptance tests,” as amended through ISO 1217:2009(E)/Amd.1:2016.

Specifically, the test procedure codified by this final rule references the following parts of ISO 1217 as amended by Amendment 1:2016: sections 2, 3, and 4; subsections 5.2, 5.3, 5.4, 5.6, 5.9, 6.2(g), and 6.2(h); Annex C subsections C.1.1, C.2.2, C.2.3, C.2.4, C.4.1, C.4.2.1, C.4.2.3, C.4.3.2 and C.4.4; Annex H subsections H.2 and H.3; and Table 1 of subsection 6.2. See section III.D and section IV.N of this final rule for additional information about ISO 1217:2009(E) and ISO 1217:2009(E)/Amd.1:2016. Members of the compressor industry developed ISO 1217:2009(E), which contains methods for determining inlet and discharge pressures, actual volume flow rate, packaged compressor power input, and package isentropic efficiency for electrically driven packaged displacement compressors. DOE has reviewed the relevant sections of ISO 1217:2009(E), as amended, and has determined that ISO 1217:2009(E), as amended, in conjunction with the additional clarifications and test methods and calculations established in this final rule (see section III.E), produces test results that reflect the energy efficiency of a compressor during a representative average use cycle. (42 U.S.C. 6314(a)(2)) DOE has also reviewed the burdens associated with conducting the test procedure established in this final rule, including ISO 1217:2009(E), as amended, and, based on the results of such analysis, has found that the test procedure would not be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2)) DOE presents the analysis of the burdens associated with the test procedure in section IV.B.

ISO 1217:2009(E)/Amd.1:2016 is titled “Calculation of isentropic efficiency and relationship with specific energy.”

In this final rule, DOE also establishes, in subpart B of part 429 of title 10 of the Code of Federal Regulations (10 CFR part 429), sampling plan requirements, representations requirements, and enforcement provisions for the compressors within the scope of this final rule. The sampling plan requirements established in this final rule are similar to other types of commercial equipment (

e.g.,

pumps) and are appropriate for compressors based on the expected range of measurement uncertainty and manufacturing tolerances for this equipment. The sampling plan is intended to give DOE reasonable assurance that any individual unit distributed in commerce is at least as efficient as its basic model rating. The representations requirements established in this final rule specify the energy consumption or energy efficiency representations that, in addition to the regulated metric (part- or full-load package isentropic efficiency), may be made by compressor manufacturers, distributors, retailers, or private labelers. DOE notes that any representations of the energy efficiency or energy use of compressors to which an adopted test procedure applies must be made based on the adopted compressor test procedure beginning 180 days after the publication date of any test procedure final rule establishing such procedures. (42 U.S.C. 6314(d)) Finally, the enforcement provisions established in this final rule govern the process DOE follows when performing its own assessment of basic model compliance with any future energy conservation standards.

III. Discussion

A. Definitions

1. Definition of Covered Equipment

Although EPCA lists compressors as a type of industrial equipment, the term is not defined. (42 U.S.C. 6311(2)(B)(i)) In the May 5, 2016 test procedure NOPR, DOE proposed to define a “compressor” as a machine or apparatus that converts different types of energy into the potential energy of gas pressure for displacement and compression of gaseous media to any higher pressure values above atmospheric pressure and has a pressure ratio

greater than 1.3. 81 FR 27220, 27223-27224. Further, DOE noted that with its proposal of a pressure ratio of greater than 1.3, it intended to align the minimum pressure ratio for compressors with the maximum ratio proposed in the fans and blowers rule and to create a continuous spectrum of coverage between the two equipment types.

Ibid.

For the final rule, the term “pressure ratio” has been revised to “pressure ratio at full-load operating pressure,” as explained later in this section.

To determine objectively and unambiguously whether equipment meets the definition of compressor, in the test procedure NOPR, DOE also proposed to define the term “pressure ratio” as the ratio of discharge pressure to inlet pressure, as determined at full-load operating pressure. Such a definition enables DOE to establish quantitatively which compressors meet the pressure ratio requirement proposed in the definition of the term compressor. 81 FR 27220, 27224 (May 5, 2016).

In the notice of final determination, DOE addressed all comments related to the definition of compressor, and ultimately adopted the following definition:

Compressor

means a machine or apparatus that converts different types of energy into the potential energy of gas pressure for displacement and compression of gaseous media to any higher pressure values above atmospheric pressure and has a pressure ratio at full-load operating pressure greater than 1.3. 81 FR 79991, 79998 (Nov. 15, 2016).

DOE notes that in the notice of final determination, for the definition of compressor, the term pressure ratio (which was proposed in the TP NOPR), was replaced with the term “pressure ratio at full load operating pressure.” DOE stated that the definition of the new term, as well as methods of testing,

would be established in the test procedure final rule. 81 FR 79991, 79995 (Nov. 15, 2016). In this final rule, DOE addresses all comments related to the definition of the term pressure ratio. CAGI did not provide any direct comments, but commented that it was in agreement with DOE's proposal for items on which it did not directly comment. (CAGI, No. 0010, p. 3) Ingersoll Rand, Sullair, and Sullivan-Palatek supported CAGI's comments. (Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1; Sullivan-Palatek, No. 0007 at p. 1)

Jenny Products and Scales Industrial Technologies commented that they would prefer to use the more common term, “compression ratio,” in place of pressure ratio. Scales Industrial Technologies also indicated that DOE's proposed definition of pressure ratio was not sufficiently clear, and could be interpreted in multiple ways. (Scales Industrial Technologies, No. 0013, at p. 1; Jenny Products, No. 0020 at p. 2)

In response to Scales Industrial Technologies' concerns about clarity, in this final rule, DOE is clarifying its NOPR proposal and modifying the term pressure ratio to pressure ratio at full-load operating pressure. This clarification better aligns the name of this metric with its definition, which states, as proposed, that pressure ratio means the ratio of discharge pressure to inlet pressure, determined at full-load operating pressure in accordance with the test procedures prescribed in § 431.344. 81 FR 27220, 27224 (May 5, 2016). DOE is making this clarification because it understands that the ratio between the inlet pressure and the discharge pressure, measured at the discharge pipe, can vary based on the pressure of the system that the compressor is supplying. As a result, DOE concludes that the use of the general term pressure ratio to describe a pressure ratio at a specific load point (

i.e.,

full-load operating pressure), is not appropriate. Additionally, based on the general support of CAGI, Sullivan-Palatek, Ingersoll Rand, and Sullair, and the above clarification to the term pressure ratio, DOE concludes that the use of the term pressure ratio at full-load operating pressure is sufficiently clear, and DOE does not adopt the term compression ratio in its place.

Ultimately, for the reasons discussed in this section and established in the test procedure NOPR, DOE is adopting the following definition for pressure ratio at full-load operating pressure. Beyond the previously discussed terminology change from pressure ratio to pressure ratio at full-load operating pressure, this definition is unchanged from the test procedure NOPR proposal.

Pressure ratio at full-load operating pressure

means the ratio of discharge pressure to inlet pressure, determined at full-load operating pressure in accordance with the test procedures prescribed in § 431.344.

2. Air Compressor

In the test procedure NOPR, DOE proposed to define the term “air compressor” as a compressor designed to compress air that has an inlet open to the atmosphere or other source of air, and is made up of a compression element (bare compressor), driver(s), mechanical equipment to drive the compressor element, and any ancillary equipment. 81 FR 27220, 27226 (May 5, 2016).

In response to the proposed definitions, DOE received comment from CAGI indicating its support of the definitions as proposed for the test procedure. (CAGI, Public Meeting Transcript, No. 0016 at p. 20) Sullivan-Palatek, Ingersoll Rand, and Sullair supported CAGI's comments. (Sullivan-Palatek, No. 0007 at p. 1; Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1)

Consequently, for the reasons established in the test procedure NOPR, DOE is adopting the definition for air compressor as proposed in the test procedure NOPR.

3. Air Compressor Components

a. Bare Compressor, Driver, and Mechanical Equipment

In the test procedure NOPR, DOE proposed to define “bare compressor”

as the compression element and auxiliary devices (

e.g.,

inlet and outlet valves, seals, lubrication system, and gas flow paths) required for performing the gas compression process. The definition does not include the driver; speed-adjusting gear(s); gas processing apparatuses and piping; or compressor equipment packaging and mounting facilities and enclosures. 81 FR 27220, 27227 (May 5, 2016).

The compressors industry frequently uses the term “airend” or “air end” to refer to the bare compressor. DOE uses “bare compressor” in the regulatory text of this rule, and, for the purposes of this rulemaking, it considers the terms to be synonymous.

Further, in the test procedure NOPR, DOE proposed to define “driver” and “mechanical equipment” as the machine providing mechanical input to drive a bare compressor directly or through the use of mechanical equipment, and any component of an air compressor that transfers energy from the driver to the bare compressor, respectively. 81 FR 27220, 27227 (May 5, 2016).

In response to the proposed definitions, CAGI did not provide any direct comments, but CAGI commented that it was in agreement with DOE's proposal for items on which it did not directly comment. (CAGI, No. 0010, p. 3) Ingersoll Rand, Sullair, and Sullivan-Palatek supported CAGI's comments. (Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1; Sullivan-Palatek, No. 0007 at p. 1) Scales Industrial Technologies commented that the `bare' compressor often includes speed-increasing gears. (Scales Industrial Technologies, no. 0013 at p. 2) In response, DOE clarifies that while the definition of bare compressor does not include mention of gears, the definition of mechanical equipment does include mention of gears. Moreover, the definition of air compressor, which is the overarching term dictating the scope of applicability of equipment in this final rule, includes mechanical equipment. Consequently, for the reasons established in the test procedure NOPR, DOE is adopting the definitions for bare compressor, driver, and mechanical equipment as proposed in the test procedure NOPR.

b. Ancillary Equipment

In the test procedure NOPR, the proposed definition of air compressor included the term “ancillary equipment.” DOE proposed to define ancillary equipment as any equipment distributed in commerce with an air compressor that is not a bare compressor, driver, or mechanical equipment. 81 FR 27220, 27227 (May 5, 2016). Ancillary equipment would be considered to be part of a given air compressor model regardless of whether the ancillary equipment is physically attached to the bare compressor, driver, or mechanical equipment at the time when the air compressor is distributed in commerce.

Ibid.

DOE also requested comment on if a list of ancillary equipment was more appropriate than the definition.

Ibid.

Many commenters suggested that the definition of ancillary equipment proposed in the test procedure NOPR lacked specificity. Scales Industrial Technologies, Kaeser Compressors, and Jenny Products commented that standard, but not application-specific or optional, ancillary equipment should be used as required for the safe operation of the bare compressor. Kaeser Compressors noted that the metric of isentropic efficiency is expressed relative to the theoretical power required to compress air, and thus the specified test configuration should

logically reflect the equipment required to compress air, without the effect of any additional components. Scales Industrial Technologies stated that standard compressors should not include accessories beyond an aftercooler, a moisture separator, and an automatic drain cap. (Jenny Products, No. 0020 at pp. 2-3; Scales Industrial Technologies, No. 0013 at p. 2; Kaeser Compressors, Public Meeting Transcript, No. 0016 at pp. 31, 37)

ASAP commented that the definition of ancillary equipment should be clear and include equipment that is normally included with a majority of applications. (ASAP, Public Meeting Transcript, No. 0016 at pp. 25, 30) Similarly, Compressed Air Systems commented that the list of ancillary equipment should be defined, noting that safety equipment should be included as part of the list to ensure safe operation of compressors. (Compressed Air Systems, No. 0008 at p. 1) Atlas Copco agreed that the proposed definition of ancillary equipment was not appropriate, and commented that DOE should consider a definition similar to the one used in the EU Lot 31 draft standard. Atlas Copco argues that following the EU Lot 31 standard would allow for accurate comparisons of the energy consumption of similar basic models of compressors and would not penalize manufacturers who efficiently integrate optional ancillary equipment into the compressor design. (Atlas Copco, No. 0009 at pp. 10-11; Atlas Copco, Public Meeting Transcript, No. 0016 at pp. 34-35) CAGI and Ingersoll Rand also supported a clearer definition and suggested the use of a list of equipment to define the term ancillary equipment, with Ingersoll Rand further commenting that optional equipment such as ancillary air treatment equipment should be excluded from the test procedures. (CAGI, Public Meeting Transcript, No. 0016 at pp. 27-28; Ingersoll Rand, Public Meeting Transcript, No. 0016 at pp. 29, 33) CAGI provided a list that is slightly modified from the one used by the EU Lot 31 draft standard; this list is reproduced in Table III.1. (CAGI, No. 0010 at p. 3; CAGI, Public Meeting Transcript, No. 0016 at p. 37) CAGI stated that this list is limited to equipment that is required for safety or basic compressor functionality. (CAGI, No. 0010 at p. 3) CAGI further indicated that all other equipment is optional and should not be included for testing. (CAGI, No. 0010 at pp. 4-5; CAGI, Public Meeting Transcript, No. 0016 at p. 37)

Table III.1—CAGI-Suggested List of Ancillary Equipment To Be Included for Testing

Configuration of basic compressor

Fixed-speed rotary

Variable-speed rotary

Speed

Fixed

Variable.

Cooling

Air-cooled/Water-cooled

Air-cooled/Water-cooled.

Electric motor (driver)

Yes

Yes.

Cooling fan(s) and motors

Yes

Yes.

Compression element (bare compressor)

Yes

Yes.

Transmission (belt, gear, coupling, etc.) (mechanical equipment)

Yes (if applicable) **

Yes (if applicable) **.

Inlet filter

Yes

Yes.

Inlet valve

Yes

Yes.

Minimum pressure check valve/backflow check valve

Yes

Yes.

Oil separator

Yes

Yes.

Air piping

Yes

Yes.

Oil piping

Yes

Yes.

Oil pump

Yes (if applicable) **

Yes (if applicable) **.

Oil filter

Yes

Yes.

Oil cooler

Yes

Yes.

Thermostatic valve

Yes

Yes.

Electrical switchgear

Yes *

No *.

Frequency converter

No *

Yes *.

Compressed air cooler(s)

Yes

Yes.

Compressor control device (pressure switch, pressure transducer, electronic or electrical controls, etc.)

Yes

Yes.

Protective devices

Yes

Yes.

Moisture separator and drain

Yes

Yes.

* Electrical switchgear and frequency converter only concern the main electric drive motor, other motors (

e.g.,

fans, pumps) may still be driven by a variable-speed drive and/or include electrical switchgear and/or frequency converter.

** The term “if applicable” means that if the functionality of the basic package is achieved without the component, then it does not need to be included.

Sullair and Sullivan-Palatek expressed support of the CAGI position and the list defined by CAGI in Table III.1; Sullivan-Palatek further argued that a consistent list of installed equipment, rather than what is included in commerce, is important such that compressors can be compared to each other consistently. (Sullair, No. 0006 at p. 7; Sullivan-Palatek, No. 0007 at pp. 3, 4; Sullivan-Palatek, Public Meeting Transcript, No. 0016 at p. 28) Ingersoll Rand expanded on the importance of using a list to define ancillary equipment, noting that manufacturers independently have been self-declaring a basic compressor when representing unit efficiency, which in turn has been used by DOE to analyze standards for compressors. (Ingersoll Rand, Public Meeting Transcript, No. 0016 at p. 36) Sullair supported comments from Kaeser Compressors and CAGI, elaborating that items not included in the list of ancillary equipment developed by CAGI are customer-driven additional equipment and out of the control of a manufacturer. (Sullair, Public Meeting Transcript, No. 0016 at pp. 33-34) NEEA commented that a filter should be included as part of the definition of ancillary equipment, but would consider dropping the suggestion of adding a filter to the list of ancillary equipment if the draft EU compressor standard also does not require a filter. (NEEA, Public Meeting Transcript, No. 0016 at p. 35)

Further, CAGI commented that if a unit is offered for sale without a piece of equipment on its recommended list, the manufacturer must provide an appropriate component, and the selection and responsibility of providing and installing this component for testing

shall be the responsibility of the manufacturer. (CAGI, No. 0010 at p. 5)

In response to these comments, DOE agrees with CAGI and other commenters that DOE should develop a list of equipment that must be present for testing. Further, DOE generally agrees with the list provided by CAGI. However, instead of including a specific list as part of the definition of ancillary equipment, DOE is maintaining a broad definition of ancillary equipment and adopting a list of equipment that must be present for testing in the equipment configuration section of the test method (see section III.E.3 for complete details). This approach helps avoid loopholes, as it ensures that compressors distributed in commerce with additional equipment outside this list are still within the scope of the test procedure, but such equipment is tested only with the equipment on the list. Further, this approach helps ensure that all compressors within the scope of this rulemaking are rated fairly and equitably with a consistent set of equipment present, addressing the concerns of Sullivan-Palatek. DOE concludes that this approach is consistent with CAGI's comments, which made clear that its list was the required subset of all potential equipment that it believed should be present for testing. As a result, DOE is adopting the definition of ancillary equipment proposed in the test procedure NOPR. Please see section III.E.3 for a complete discussion of specific equipment that is required for testing.

4. Rotary and Reciprocating Compressors

In the test procedure NOPR, DOE proposed the following definitions for rotary and reciprocating compressors:

Rotary compressor

means a positive displacement compressor in which gas admission and diminution of its successive volumes or its forced discharge are performed cyclically by rotation of one or several rotors in a compressor casing. 81 FR 27220, 27228 (May 5, 2016).

Reciprocating compressor

means a positive displacement compressor in which gas admission and diminution of its successive volumes are performed cyclically by straight-line alternating movements of a moving member(s) in a compression chamber(s). 81 FR 27220, 27228 (May 5, 2016).

To support these definitions, DOE also proposed “positive-displacement compressor” to mean a compressor in which the admission and diminution of successive volumes of the gaseous medium are performed periodically by forced expansion and diminution of a closed space(s) in a working chamber(s) by means of displacement of a moving member(s) or by displacement and forced discharge of the gaseous medium into the high-pressure area.

In response to the proposed definitions, CAGI agreed with the proposed compressor definitions, but stated that defining “rotor” would characterize the equipment more accurately, and suggested the following definition: A compression element that rotates continually in a single direction [around] a single shaft or axis. (CAGI, No. 0010 at p. 5) CAGI further commented that, beyond rotary screw compressors, other types of rotary compressors, such as rotary vane and scroll, would be covered under the definition. (CAGI, Public Meeting Transcript, No. 0016 at p. 22) However, CAGI did not specifically recommend whether these other rotary compressors should, or should not, be included within the scope of the test procedure. Sullair added that DOE should clarify which compressor technologies, such as scroll and vane, met the proposed definition. (Sullair, Public Meeting Transcript, No. 0016 at p. 23) Sullivan-Palatek, Ingersoll Rand, and Sullair supported CAGI's comments. (Ingersoll Rand, No. 0011 at p. 1; Sullivan-Palatek, No. 0007 at p. 1; Sullair, No. 0006 at p. 1)

DOE agrees with CAGI and Sullair's comments that a definition of rotor and examples of rotary compressors would improve the accuracy of the rotary compressor definition. Further, DOE agrees with CAGI's recommended definition and finds it to be technically accurate. For this reason, in this final rule, DOE is adopting the definition of rotor, as recommended by CAGI. In response to Sullair's request for examples, DOE notes that rotary compressors include, but are not limited to, rotary screw, sliding vane, rotary lobe, and liquid ring. However, DOE does not believe that scroll compressors meet the definition of rotary compressors, as scroll compressors nutate (or orbit) rather than rotate continually in a single direction around a single shaft or axis.

Beyond these clarifications, DOE is making no changes to the remaining definitions discussed in this subsection, and for the reasons established in the test procedure NOPR, DOE is adopting in this final rule the definitions for rotary compressor, reciprocating compressor, and positive-displacement compressor, as proposed in the test procedure NOPR.

5. Brushless Electric Motor

In the test procedure NOPR, DOE proposed to define a “brushless electric motor” as a machine that converts electrical power into rotational mechanical power without use of sliding electrical contacts. Further, DOE considered brushless motors to include, but not be limited to, what are commonly known as induction, brushless direct current, permanent magnet, electrically commutated, and reluctance motors. 81 FR 27220, 27229 (May 5, 2016).

In response to the proposed definitions, CAGI did not provide any direct comments, but commented that it was in agreement with DOE's proposal for items on which it did not directly comment. (CAGI, No. 0010, p. 3) Ingersoll Rand, Sullair, and Sullivan-Palatek supported CAGI's comments. (Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1; Sullivan-Palatek, No. 0007 at p. 1) Consequently, for the reasons established in the test procedure NOPR, DOE is adopting the definition for brushless motor as proposed in the test procedure NOPR.

6. Compressor Motor Nominal Horsepower

In the test procedure NOPR, DOE proposed “compressor motor nominal horsepower” (“hp”) to mean the motor horsepower of the electric motor with which the rated air compressor is distributed in commerce, as determined in accordance with the applicable procedures in subparts B and X of 10 CFR part 431. 81 FR 27220, 27229 (May 5, 2016).

In response to the proposed definitions, CAGI did not provide any direct comments, but commented that it was in agreement with DOE's proposal for items on which it did not directly comment. (CAGI, No. 0010, p. 3) Ingersoll Rand, Sullair, and Sullivan-Palatek supported CAGI's comments. (Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1; Sullivan-Palatek, No. 0007 at p. 1) Consequently, for the reasons established in the test procedure NOPR, DOE is adopting in this final rule the definition for compressor motor nominal horsepower as proposed in the test procedure NOPR.

7. Volume Flow Rates

In the test procedure NOPR, DOE proposed that “actual volume flow rate” mean the volume flow rate of air, compressed and delivered at the standard discharge point, referred to conditions of total temperature, total pressure, and composition prevailing at the standard inlet point, and as

determined in accordance with the test procedures proposed for 10 CFR 431.344. Further, DOE also proposed that full-load actual volume flow rate mean the actual volume flow rate of the compressor at the full-load operating pressure. 81 FR 27220, 27231 (May 5, 2016).

8. Maximum Full-Flow Operating Pressure

In the test procedure NOPR, DOE proposed “maximum full-flow operating pressure” to mean the maximum discharge pressure at which the compressor is capable of operating, as determined in accordance with the test procedures proposed for 10 CFR 431.344.

81 FR 27220, 27231 (May 5, 2016).

A discussion of the test procedure to determine the maximum full-flow operating pressure can be found in section III.E.9.

In response to the proposed definition, CAGI did not provide any direct comments, but CAGI commented that it was in agreement with DOE's proposal for items on which it did not directly comment. (CAGI, No. 0010, p. 3) Ingersoll Rand, Sullair, and Sullivan-Palatek supported CAGI's comments. (Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1; Sullivan-Palatek, No. 0007 at p. 1) Consequently, for the reasons established in the test procedure NOPR, in this final rule DOE is adopting the definition for maximum full-flow operating pressure proposed in the test procedure NOPR.

9. Lubricated Compressor

In the energy conservation standards NOPR, DOE proposed “lubricated compressor” to mean a compressor that introduces an auxiliary substance into the compression chamber during compression. 81 FR 31680, 31698 (May 19, 2016). Analogously, DOE proposed “lubricant-free compressor” to mean a compressor that does not introduce any auxiliary substance into the compression chamber at any time during operation. 81 FR 31680, 31698 (May 19, 2016). To support these definitions, DOE proposed “auxiliary substance” to mean any substance deliberately introduced into a compression process to aid in compression of a gas by any of the following: Lubricating, sealing mechanical clearances, and/or absorbing heat. 81 FR 31680, 31698 (May 19, 2016).

In the energy conservation standards NOPR, DOE discussed ISO Standard 8573-1:2010, “Compressed air—Part 1: Contaminants and purity classes,” (hereinafter referred to as “ISO 8573-1:2010”) which is used by industry to measure and describe the purity of air.

DOE did not propose to use ISO 8573-1:2010, but requested comment on the suitability of using this standard to characterize compressors based on the presence of lubricant in the compression chamber. 81 FR 31680, 31698 (May 19, 2016).

Available at:

http://www.iso.org/iso/catalogue_detail.htm?csnumber=46418

In response, CAGI commented that ISO 8573-1:2010 is a standard for measuring the quality of air and, as such, is not suitable for determining the presence of lubricant in the compression chamber. (EERE-2013-BT-STD-0040, CAGI, No. 0052 at p. 10) Ingersoll Rand, Mattei Compressors, Sullair, and Sullivan-Palatek commented in support of CAGI's recommendations. (Ingersoll Rand, No. 0055 at p. 1; Mattei Compressors, No. 0063 at p. 2; Sullair, No. 0056 at p. 1; Sullivan-Palatek, No. 0051 at p. 1) Beyond this commentary, CAGI provided no comments or recommendations regarding the definitions of lubricated compressor and lubricant-free compressor, as proposed in the energy conservation standard NOPR. Kaeser Compressors commented that ISO 8573-1:2010 is not suitable for defining a lubricated compressor and agreed with DOE's approach in the NOPR regarding the definition of an auxiliary substance without reference to ISO 8573-1:2010. (Kaeser Compressors, Public Meeting Transcript, No. 0044 at p. 21)

DOE agrees with the comments made by CAGI, Ingersoll Rand, Mattei Compressors, Sullair, Sullivan-Palatek, and Kaeser Compressors, and does not use ISO 8573-1:2010 in the definition of lubricated compressor in this final rule. Additionally, due to the reasons established in the test procedure NOPR, and due to support from Kaeser Compressors, in this final rule DOE is adopting the definitions for lubricated compressor, lubricant-free compressor, and auxiliary substance as proposed in the energy conservation standards NOPR.

B. Scope of Applicability of the Test Procedure

In the test procedure NOPR, DOE proposed to limit the scope of applicability of the compressors test procedures to compressors that meet the following criteria:

• Are air compressors;

• are rotary or reciprocating compressors;

• are driven by a brushless electric motor;

• are distributed in commerce with a compressor motor nominal horsepower greater than or equal to 1 hp and less than or equal to 500 hp; and

• operate at a full-load operating pressure of greater than or equal to 31 pounds per square inch, gauge (“psig”) and less than or equal to 225 psig;

The proposed test procedure NOPR scope directly aligned with the scope of compressor equipment that DOE analyzed for the May 5, 2016 energy conservation standards NOPR for compressors. 81 FR 27220, 27224-5. Similarly, in this final rule, DOE intends to directly align the scope of the compressors test procedures with the scope of the forthcoming energy conservation standards final rule. However, while DOE intends the scope of the test procedures adopted in this final rule to be consistent with that of any energy conservation standard that may eventually be established for compressors, DOE notes that the scope of any energy conservation standards will be established as part of a separate rulemaking.

As such, based on comments received in response to both the test procedure and energy conservation standards NOPR, the scope of this test procedure final rule is limited to compressors that meet the following criteria:

• Are air compressors;

• are rotary compressors;

• are not liquid ring compressors;

• are driven by a brushless electric motor;

• are lubricated compressors;

• have a full-load operating pressure of 75-200 psig;

• are not designed and tested to the requirements of The American Petroleum Institute standard 619, “Rotary-Type Positive-Displacement Compressors for Petroleum, Petrochemical, and Natural Gas Industries;” and

• have a capacity that is either:

o 10-200 compressor motor nominal horsepower (hp), or

o 35-1,250 full-load actual volume flow rate (cfm).

Detailed discussion of each of the scope limitations, associated benefits and burdens, and interested party comments, are in the subsections that follow.

1. Air Compressor Limitation

In the test procedure NOPR, DOE proposed to limit the scope of the compressors test procedure to air compressors, as defined in section III.A.2.

In response to the 2012 NOPD, Ingersoll Rand commented that losses in efficiency are often attributable to system-level losses as opposed to package-level losses. Ingersoll Rand stated that, therefore, little benefit would be achieved by regulating the compressor package alone without providing guidance for the overall compressed air system. (Docket No. EERE-2012-BT-DET-0033, Ingersoll Rand, No. 0004 at p. 2) CAGI argued that estimating compressor energy consumption, alone, is difficult because it is often operated in an ensemble of accompanying equipment, including other compressors. (Docket No. EERE-2012-BT-DET-0033, CAGI, No. 0003, at pp. 5-6)

In response to the more recent 2016 test procedure NOPR, CAGI and Ingersoll Rand provided updated positions on the subject, and agreed with DOE's proposal for items on which they did not directly comment. (CAGI, No. 0010 at p. 3; Ingersoll Rand, No. 0011 at p. 1) Sullivan-Palatek and Sullair supported CAGI's comments. (Sullivan-Palatek, No. 0007 at p. 1; Sullair, No. 0006 at p. 1) CASTAIR disagreed with the notion of efficiency standards for air compressors, arguing that DOE should only regulate the manufacturers of bare compressors, as air compressor assemblers have very little control over efficiency. (CASTAIR, No. 0018 at p. 1)

In response to CASTAIR, the efficiency of an air compressor is not solely a function of the bare compressor. As DOE discussed in the test procedure NOPR, opportunities exist to select high efficiency motors, drives (if applicable), mechanical equipment, and ancillary equipment that affect efficiency. Further, proper sizing and integration of this equipment also influences efficiency. In the test procedure NOPR, DOE specifically evaluated the option of regulating at the bare compressor and packaged compressor level. For the reasons just mentioned, DOE concluded that regulating a bare compressor would result in significantly lower energy savings opportunity compared to the packaged compressors. Further, DOE concluded that determining the energy performance of the bare compressor alone would not be representative of the energy consumption of the equipment under typical use conditions. 81 FR 27220, 27225 (May 5, 2016).

Based on these reasons and the support of many interested parties, DOE maintains its NOPR proposal, and is limiting the scope of the compressors test procedure final rule to air compressors as defined in section III.A.2 of this final rule.

2. Rotary and Reciprocating Compressors

In the test procedure NOPR, DOE proposed to include only rotary and reciprocating compressors within the scope of the test procedure, and not to include dynamic compressors. 81 FR 27220, 27228 (May 5, 2016).

In response to the test procedure NOPR, the CA IOUs supported the inclusion of reciprocating compressors in the scope of the test procedure and recommended that DOE require testing and performance data reporting for reciprocating compressors, noting that making their performance data publicly available would be helpful for future rulemakings and utility incentive programs. The CA IOUs recommended a phased approach for reciprocating compressors to reduce the burden on manufacturers, in which testing and reporting of performance data would be required over a long period of time. (CA IOUs, No. 0012 at p. 4)

Sullair commented that any equipment covered by the test procedure and not the standard presents a significant burden to the manufacturer and a competitive advantage to competing unregulated technologies without a resulting improvement in unit efficiency. (Sullair, No. 0006 at p. 3)

DOE agrees with the CA IOUs that establishing test procedures and public reporting requirements for reciprocating compressors could be helpful in future rulemakings and utility incentive programs. However, in the energy conservation standards NOPR, DOE concluded that energy conservation standards for reciprocating compressors are not economically justified at this time; as such, DOE did not propose energy conservation standards for reciprocating compressors. 81 FR 31680 (May 19, 2016). As discussed previously, and in agreement with Sullair's comments, DOE concludes that in the absence of existing or proposed energy conservation standards for reciprocating equipment, establishing a test procedure to measure performance of such equipment is not warranted at this time. Further, DOE concludes that the burdens associated with such a test procedure, as discussed by Sullair, outweigh any potential benefits at this time. Consequently, in this final rule, DOE is adopting test methods applicable only to certain rotary compressors and is not adopting any testing requirements for reciprocating compressors at this time.

In response to the concurrent energy conservation standards rulemaking, ASAP, NEEA, NWPCC, CA IOUs, and Sullivan-Palatek suggested that DOE's consideration of reciprocating compressors as one, monolithic category may be inappropriate, as reciprocating compressors are built to a wide range of efficiencies, intended duty cycles, and configurations based on capacity. Further, Sullivan-Palatek suggested that a fraction of compressors in the reciprocating market are likely to be used in industrial settings and may be worth considering separately from the rest. (EERE-2013-BT-STD-0040, NEEA and NWPCC, No. 0057 at pp. 1-2; Docket No. EERE-2013-BT-STD-0040, ASAP, Public Meeting Transcript, No. 0044 at pp. 151-152; Docket No. EERE-2013-BT-STD-0040, CA IOUs, No. 0059 at p. 3; Docket No. EERE-2013-BT-STD-0040, Sullivan-Palatek, Public Meeting Transcript, No. 0044 at pp. 67-68, 84-85, 87, 112-113, 114, 115-116) DOE acknowledges these suggestions and concludes that separately reassessing certain segments of the reciprocating marketing may lead DOE to a better informed assessment of the burdens and benefits of test procedures and energy conservation standards for reciprocating compressors. However, at this time, insufficient data exists to perform such a specific characterization of the reciprocating market, as noted by NEEA. (Docket No. EERE-2013-BT-STD-0040, NEEA, Public Meeting Transcript, No. 0044 at pp. 123-124) Consequently, DOE concludes the most suitable path forward is to explore the appropriateness of test procedures and energy conservation standards for reciprocating compressors in a future, separate rulemaking.

As a point of clarification, DOE notes that compressors that combine more than one type of compression principle (

e.g.,

rotary and reciprocating elements within a single compressor package) do not meet DOE's adopted definition of rotary compressor, and, therefore, are subject to the test procedures adopted in this final rule.

As noted in section III.A.4, liquid ring compressors meet the definition of a rotary compressor. Specifically, ISO

1217:2009(E), as amended,

defines “liquid ring compressor” as a machine with a rotating impeller with protruding blades eccentrically mounted in a stationary round housing or centrally mounted in a stationary elliptical housing.

In this final rule, DOE is incorporating by reference parts of ISO 1217:2009(E) as amended by Amendment 1:2016. Amendment 1:2016 did not introduce any changes in regards to this particular topic. For details on ISO 1217:2009(E) and Amendment 1:2016, see III.D and IV.N.

In this final rule, DOE is explicitly excluding liquid ring compressors from the scope of applicability of this test procedure. Although liquid ring compressors are rotary compressors, they provide a unique utility for applications that require a durable compressor tolerant of dirty input air and ingested liquid. Due to this utility and construction, liquid ring compressors require test methods different from those proposed in the test procedure NOPR. Specifically, ISO 1217:2009(E), as amended,

specifies that due to their configuration, liquid ring compressors should be tested to Annex A, which provides testing methods and accuracy tolerances that differ from those contained in the sections that DOE proposed to incorporate by reference in the test procedure NOPR. As a result, DOE concludes that it is not appropriate to include liquid ring compressors in the scope of this test procedure final rule. However, DOE retains the authority to evaluate and propose appropriate test methods for liquid ring compressors in future rulemakings.

In this final rule, DOE is incorporating by reference parts of ISO 1217:2009(E) as amended by Amendment 1:2016. Amendment 1:2016 did not introduce any changes in regards to this particular topic.

3. Driver Style

a. Electric Motor- and Engine-Driven Compressors

In the test procedure NOPR, DOE proposed to limit the scope of the compressors test procedure to only compressors driven by electric motors. In response, EEI expressed disappointment that the scope of the proposed energy conservation standard for compressors and, by extension, the test procedure was not fuel-neutral, noting that there are compressors driven by natural gas. (Docket No. EERE-2013-BT-STD-0040, EEI, Public Meeting Transcript, No. 0044 at p. 5)

In response to EEI's comment, DOE considered engine-driven compressors in the February 5, 2014 Framework document for compressors and discussed these extensively in the May 5, 2016 test procedure NOPR. 79 FR 6839 and 81 FR 27220. Specifically, in the test procedure NOPR, DOE concluded that the inclusion of engine-driven compressors was not appropriate for various reasons, including their differing utility as compared to electric compressors, their existing coverage under the U.S. Environmental Protection Agency's Tier 4 emissions regulations, and the limited test data available under Annex D of ISO 1217:2009(E) to verify suitability as a DOE test procedure. For these reasons, DOE noted that engine-driven compressors would more appropriately be considered as part of a future rulemaking. 81 FR 27220, 27229 (May 5, 2016). DOE continues to conclude that engine-driven compressors are unique equipment with different performance, applications, and test requirements from air compressors driven by electric motors. However, as noted in the test procedure NOPR, DOE currently lacks the performance data and product information to develop and validate such procedures. Therefore, DOE continues to conclude engine-driven compressors would be more appropriately addressed as part of a separate rulemaking specifically considering such equipment. As such, DOE is limiting the scope of this compressors test procedure final rule to only compressors driven by electric motors.

b. Electric Motor Varieties

In the test procedure NOPR, DOE proposed limiting the scope of the compressors test procedures to only compressors driven by brushless electric motors, as defined in section III.A.5. Further, DOE discussed the differences between brushed and brushless motors and noted that brushed motors are uncommon in compressors with significant operating hours due to higher maintenance requirements, lower efficiency, acoustic noise, and electrical arcing. However, DOE noted that compressors with brushed motors could be considered in the future as part of a separate rulemaking. 81 FR 27220, 27229 (May 5, 2016).

In response to DOE's test procedure NOPR, NEEA stated that manufacturers may avoid regulation by changing the motor technology. (NEEA, Public Meeting Transcript, No. 0016 at p. 56) In response, DOE reiterates that brushed motors are uncommon in compressors with significant potential energy savings (

i.e.,

high operating hours) due to higher maintenance costs, short operating lives, significant acoustic noise, and electrical arcing. For these reasons, DOE concludes that brushed motors are not a viable substitution risk for compressors within the scope of the compressor test procedures.

In a joint comment, ASAP and NEEA recommended that DOE expand the scope of the test procedures so that it includes all kinds of electric motors, rather than exclusively covering brushless motors. ASAP and NEEA reasoned that the test procedures should be broad so that they could be applicable to possible future energy conservation standards and could be used to collect a wide range of compressor performance data. (ASAP and NEEA, No. 0015 at p. 1)

In response, DOE acknowledges the potential benefits of standardized test procedures and reporting requirements in making available consistent performance information for utility programs and consumers. However, with these potential benefits come potential burdens. If DOE were to include this equipment in the scope of the test procedures and require reporting of performance data, the burden would be significant, as most brushed motor compressors are not currently tested for efficiency. Consequently, manufacturers of this equipment, many of which are small, would face significant third-party testing costs or test lab development costs. Alternatively, DOE could adopt

optional

testing and certification requirements for brushed motor compressors. However, doing so may not have the desired effect of making more certified performance data available, as this equipment is not currently tested and energy performance is not currently represented. Therefore, based on this discussion, at this time, the burden associated with establishing testing requirements for brushed motor compressors outweigh the associated benefits.

4. Compressor Capacity

In the test procedure NOPR, DOE proposed to limit the scope of the test procedures to compressors that met the following capacity criteria:

• Compressor motor nominal horsepower of 1-500 hp.

• full-load operating pressure 31-225 psig.

81 FR 27220, 27230 (May 5, 2016).

In the test procedure NOPR, DOE did not propose scope restrictions based on the actual volume flow rate (expressed in cfm).

As noted in the test procedure NOPR, the intent of the compressor capacity criteria used to establish the scope of the test procedures was to encompass the majority of the rotary and reciprocating compressor market

intended for use in non-specialty applications. 81 FR 27220, 27224-27230 (May 5, 2016). However, in the test procedure NOPR, DOE noted that most equipment operating at an output pressure of greater than 215 psig is highly engineered equipment, primarily used in specialty applications. DOE also recognized that there are relatively few compressed air applications in the 31 to 79 psig range. 81 FR 27220, 27230 (May 5, 2016).

a. Compressor Motor Nominal Horsepower Limitations

In response to the proposed compressor motor nominal horsepower scope of 1-500 hp, CAGI recommended limiting the scope of the test procedures to compressors with compressor nominal motor horsepower of 10-200 hp. CAGI suggested that the inclusion of larger compressors (

i.e.,

greater than 200 hp) would be burdensome and cause problems with certification and enforcement as they are infrequently built and often customized. Further, CAGI noted that while the test procedures are technically appropriate for 1-500 hp compressors, the data upon which the energy conservation standard regression curves were developed is not readily available for smaller and larger compressors. (CAGI, No. 0010, p. 6) Kaeser Compressors, Ingersoll Rand, Sullair, and Sullivan-Palatek supported CAGI's scope suggestion, while Scales Industrial Technologies suggested a horsepower scope of 15-200 or 250 hp. (Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at pp. 1-8; Sullivan-Palatek, No. 0007 at pp. 1, 3; Scales Industrial Technologies, No. 0013 at pp. 3, 7; Kaeser Compressors, Public Meeting Transcript, No. 0016 at p. 46; Sullair, Public Meeting Transcript, No. 0016 at pp. 40-41, 47; Sullivan-Palatek, Public Meeting Transcript, No. 0016 at p. 56; Ingersoll Rand, Public Meeting Transcript, No. 0016 at p. 53)

Compressed Air Systems commented that there are few 1-hp rotary compressors manufactured and suggested that the test procedures burden would outweigh the energy savings potential. (Compressed Air Systems, No. 0008 at p. 1) Sullair agrees that the test procedure for low horsepower compressors would be burdensome, but commented that the volume of compressors manufactured in the low horsepower range are high. (Sullair, No. 0006 at pp. 5-6) P. R. China also commented that the DOE did not provide adequate justification to include low horsepower compressors in the scope of the test procedure. (P. R. China, No. 0019 at p. 3) P. R. China further stated that, in accordance with Article 2.5 of the TBT Agreement, they are entitled to an explanation for the justification for a technical regulation that may impact the trade opportunities of those in the agreement. (P. R. China, No. 0019 at p. 3) DOE interprets P. R. China's comments as challenging the rationale of including small capacity compressors with small nominal horsepower motors in the scope of the test procedure NOPR.

Sullair suggested that the testing burden associated with including rotary compressors less than 10 hp and greater than 200 hp in scope would create an unfair competitive advantage for non-regulated competing equipment; specifically, reciprocating or scroll compressors on the low end and centrifugal compressors on the high end. Sullair indicated that such burden may completely eliminate the larger rotary screw compressors from the market and significantly hurt the sales of the smaller ones. (Sullair, No. 0006 at pp. 2-3, 5-6) Kaeser Compressors indicated similar concerns of product substitution, citing 350 hp, rather than 200 hp. (Kaeser Compressors, Public Meeting Transcript, No. 0016 at p. 51) Beyond the financial burden, CAGI and Sullair commented about the difficulty of testing large compressors over 200 horsepower. Specifically, Sullair stated that the test equipment and environmental chamber required for compressors above 200 horsepower are unreasonably costly. (Sullair, No. 0006 at p. 4; CAGI, Public Meeting Transcript, No. 0016 at p. 50)

Kaeser Compressors further stated that compressor customization, such as customer-driven motor substitutions or modifications due to unique environments, are more common on units above 300 hp. (Kaeser Compressors, Public Meeting Transcript, No. 0016 at p. 46) CAGI, Sullair, and Sullivan-Palatek made similar comments, noting that large horsepower compressors are more frequently customized. Sullair and Sullivan-Palatek defined large horsepower compressors as compressors with greater than 200 horsepower. (CAGI, No. 0010 at p. 6; Sullair, No. 0006 at p. 4; Sullair, No. 0006 at pp. 7-8; Sullivan-Palatek, No. 0007 at p. 3)

Additionally, CAGI cited that its current Performance Verification Program covers compressors with motor power of 5-200 hp. CAGI clarified that manufacturers may publicly rate equipment beyond 200 hp with the CAGI performance data sheet; however, this equipment is not subject to the CAGI Performance Verification Program. (CAGI, Public Meeting Transcript, No. 0016 at pp. 50, 54-55) Conversely, Atlas Copco and the CA IOUs recommended that DOE expand the scope of the test procedures to equipment with compressor motor horsepower greater than 500 hp, with Atlas Copco citing harmonization with the draft EU standard for compressors and noting that the ISO 1217:2009(E) standard is applicable to compressors above 500 horsepower. (Atlas Copco, No. 0009 at p. 11; CA IOUs, No. 0012 at p. 4)

In response to the 2012 NOPD, EEI argued that large electric motors (

i.e.,

of greater than 500 horsepower), relative to other sizes, carried the greatest per-unit energy consumption and tended to be operated at high duty cycles. EEI noted that this tendency to operate at high duty cycles may simplify development of a test procedure and that, on the account of both test procedure simplicity and large unit energy consumption, DOE should prioritize large compressors and common gases. (Docket No. EERE-2012-BT-DET-0033, EEI, No. 0009, at p. 8)

In summary, one group of commenters (CAGI, Compressed Air Systems, Kaeser Compressors, Ingersoll Rand, P. R. China, Scales Industrial Technologies, Sullair, and Sullivan-Palatek) favors a significant reduction in compressor motor nominal horsepower scope (to approximately 10-200 hp, depending on commenter). This group suggests that significant test burden would be incurred if the smaller and larger horsepower range were to be kept in scope, and this burden could lead to competitive advantage for unregulated compressors. This group also cites weakness in the data used to evaluate less than 10 hp compressors in the energy conservation standards NOPR as a reason to limit the lower horsepower range. Another group (Atlas Copco, CA IOUs, and EEI) favors expansion of scope to all equipment for which the test method is technically applicable. EEI, while not outright calling to exclude lower horsepower ratings, implies that DOE's first attention should go to larger compressors.

In general, DOE agrees with the concerns that the representations, sampling, and enforcement provisions proposed in the test procedure NOPR may cause significant burden for compressors greater than 200 hp, as many of the larger horsepower models are custom or infrequently built and typically not available for testing. Additionally, DOE agrees with Kaeser Compressors and Sullair that DOE's proposed inclusion of small (less than 10 hp) and larger (greater than 200 hp) rotary compressors, could create a competitive disadvantage for

manufacturers of these compressors, as centrifugal, reciprocating, and scroll compressors of the same horsepower do not have the same testing and representations requirements. Furthermore, DOE concludes that this competitive advantage may incentivize end users to switch from a regulated (rotary) to an unregulated (centrifugal and reciprocating) compressor, thus creating an unfair and undue burden on certain manufacturers.

In response to Atlas Copco and the CA IOUs suggestions to expand scope, DOE acknowledges the potential benefits of standardized test procedures and reporting requirements in making available consistent performance information for utility programs and consumers. However, DOE also recognizes that with these potential benefits come potential burdens. Based on the comments received and the discussion in this section, DOE concludes that the burden of testing requirements on compressors certain smaller and larger compressors outweigh the benefits. DOE acknowledges that multiple recommendations for horsepower limitations were put forward. Of the commenters supporting a reduction in horsepower cost, the overwhelming majority recommended the 10-200 hp range. For these reasons, DOE is limiting the scope of the test procedures to only compressors with 10-200 compressor nominal motor horsepower. DOE notes that this limitation on compressor nominal motor horsepower is coupled with a limit of compressor full-load actual volume flow rate, as discussed in section III.B.4.b.

b. Full-Load Actual Volume Flow Rate Limitations

CAGI and Sullair commented that the absence of a maximum airflow limit may encourage manufacturers of compressors to equip units with higher horsepower motors than the unit requires to avoid regulatory coverage. CAGI and Sullair then suggested that DOE adopt a hybrid scope limitation. Specifically, CAGI proposed a horsepower range of 10-200 hp or an actual volume flow rate range of 35-1,250 cfm. Sullair proposed a horsepower range of 10-200 hp or, an actual volume flow rate of 30-1,250 cfm (whichever is less). (Docket No. EERE-2013-BT-STD-0040, CAGI, No. 0052 at p. 9; Sullair, No. 0006 at pp. 2, 4-5; Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at pp. 9-10; Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at p. 11; Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at pp. 11-12; Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at p. 13) CAGI's position is supported by Ingersoll Rand, Kaeser Compressors, Sullair, and Sullivan-Palatek. (Docket No. EERE-2013-BT-STD-0040, Ingersoll Rand, No. 0055 at p. 1; Docket No. EERE-2013-BT-STD-0040, Kaeser Compressors, No. 0053 at p. 1; Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at p. 1; Docket No. EERE-2013-BT-STD-0040, Sullivan-Palatek, No. 0051 at p. 1)

DOE agrees with CAGI and Sullair that, by not limiting flow rate, manufacturers could conceivably circumvent the intent of compressor regulations by using a motor of horsepower slightly greater than 200 hp. For example, two similar compressors, one with a 200 hp motor and one with a 225 hp motor, would supply nearly identical flow rates and pressure (

i.e.,

utility) to the end user, however the compressor equipped with the 225 hp motor would not be subject to the test procedure, as proposed in the NOPR. In DOE's view, any alteration in flow rate directly impacts consumer utility. Additionally, a flow limitation is consistent with the EU Lot 31 draft standard, which proposes to regulate compressors with airflow of between 5 and 1,280 liters per second (l/s) (approximately 10.6-2,712 cfm).

A review of all available CAGI performance data sheets indicates that the flow rate ranges recommended by CAGI and Sullair are reasonable. The full-load actual volume flow rate range of 35-1,250 cfm is slightly broader than the compressor motor nominal horsepower range of 10-200 hp;

i.e.,

the flow range encompasses slightly more compressor models. This aligns with the intent of the recommendations put forth by CAGI and Sullair. Specifically, the full-load actual volume flow rate range of 35-1,250 cfm incorporates 9.2 percent more fixed-speed compressors and 2.9 percent more variable-speed compressors as subject to the test procedure than would otherwise be included with the compressor motor nominal horsepower range of 10-200 hp alone. For the reasons outlined in this section, in this final rule, DOE adopts a coupled airflow and horsepower limit, as recommended by Sullair and CAGI. DOE notes that the recommendations from Sullair and CAGI are not completely aligned, with Sullair recommending a lower limit of 30 cfm and CAGI recommending a lower limit of 35 cfm. Given general support by Ingersoll Rand, Kaeser Compressors, Sullair, and Sullivan-Palatek for CAGI's recommendations, DOE is adopting the lower limit of 35 cfm. Specifically, the test procedure applies to compressors with either a nominal horsepower of 10-200 horsepower or a full-load actual volume flow rate between 35-1,250 cubic feet per minute.

c. Full-Load Operating Pressure Limitations

In response to the operating pressure range proposed in the test procedure NOPR, CAGI suggested reducing the range to compressors with a full-load operating pressure of 75-200 psig, noting that outside this range, the package isentropic efficiency of a compressor is no longer independent of pressure. (CAGI, No. 0010 at p. 6) Ingersoll Rand, Sullair, and Sullivan-Palatek supported CAGI's position. (Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1; Sullivan-Palatek, No. 0007 at p. 1; Sullivan-Palatek, No. 0007 at p. 3; Sullivan-Palatek, Public Meeting Transcript, No. 0016 at p. 40) CAGI further stated that their recommended pressure range of 75-200 psig covers the primary market for rotary compressors, which the DOE defines as 80-139 psig according to the NOPR. (CAGI, Public Meeting Transcript, No. 0016 at p. 40) Jenny Products also recommended a range of 75-200 psig and stated that nearly all of the compressors sold in commerce would be covered under this range. (Jenny Products, No. 0020 at p. 3)

Atlas Copco asserted that it is incorrect for DOE to state that isentropic efficiency is independent of pressure. Instead, Atlas Copco commented that the correct statement is that isentropic efficiency is less dependent on pressure than specific energy is dependent on pressure. To support this assertion, Atlas Copco provided a chart of pressure versus isentropic efficiency, for what DOE infers to be a single compressor. Atlas Copco further stated that the chart shows the relative independence of isentropic efficiency with respect to outlet pressure between 80-170 psig (7-15 bar),

which was the motivation for the air compressor industry to use isentropic efficiency in Lot 31. (Atlas Copco, No. 0009 at pp. 16-17) DOE notes that Atlas Copco's unit conversions are incorrect; 80 to 170 psig does not convert to 7 to 15 bar (g), rather this range converts to 5.5 to 11.7 bar (g) (or 6.5 to 12.7 bar absolute), which is inconsistent with the scope proposed in the EU Lot 31 draft standard.

In the EU draft standard, the

European Commission proposed to establish a scope of 7 to 14 bar (g), which converts to 101.5 to 203.1 psig.

The commenter did not specify whether it meant absolute or gauge pressure. DOE's response in the following sentence addresses both possibilities.

Available at:

http://www.regulations.gov/contentStreamer?documentId=EERE-2013-BT-STD-

0040-0031&disposition=attachment&contentType=pdf

In response, DOE acknowledges the commenters concerns that package isentropic efficiency may not be pressure independent at the lower and upper regions of the 31 to 225 psig full-load operating pressure scope, as DOE had originally assumed in the test procedure and energy conservation standards NOPR. As discussed previously, CAGI, Ingersoll Rand, Sullivan-Palatek, and Sullair suggested 75 to 200 psig as the range over which package isentropic efficiency can be considered relatively independent of pressure. Alternatively, Atlas Copco suggested that 80 to 170 psig (7 to 15 bar) [sic] as the range over which the dependence of isentropic efficiency on outlet pressure is limited. However, as discussed previously, Atlas Copco's unit conversions were inaccurate and their suggested range does not align with the scope proposed in the EU Lot 31 draft standard. Based these ambiguities, DOE cannot directly consider Atlas Copco's recommendation when considering the range for which package isentropic efficiency can be considered independent of full-load operating pressure. As such, DOE defers to the recommendation of CAGI, Ingersoll Rand, Sullivan-Palatek, and Sullair, and concludes that package isentropic efficiency can be considered independent of full-load operating pressure at full-load operating pressures between 75 and 200 psig. DOE notes that the EU draft standard proposed to establish a scope of 101.5 to 203.1 psig,

and concluded that isentropic efficiency is independent of pressure within this range of full-load operating pressure. Part of DOE's rationale for selecting package isentropic efficiency as a test metric for compressors, as explained in the test procedure NOPR, was that package isentropic efficiency was believed to be pressure independent—meaning that attainable package isentropic efficiency varies as function of flow, but not pressure. 81 FR 27220, 27232 (May 5, 2016) and 81 FR 31680, 31705 (May 19, 2016). DOE values dependence on one parameter (flow) rather than two (flow and pressure), as it reduces the complexity (and ultimately the burden) of the related energy conservation standards and analyses. DOE's intent in the test procedure NOPR was to limit the scope to those compressors for which package isentropic efficiency and pressure are independent. However, given the new information (

i.e.,

pressure dependence at certain full-load operating pressures), DOE acknowledges that package isentropic efficiency may not be the most appropriate metric to describe the energy performance of such equipment, and further investigation is necessary. Therefore, in this final rule, DOE is limiting the scope of the test procedures to compressors within a full-load operating pressure range of 75-200 psig. However, in the future DOE may further investigate package isentropic efficiency and other metrics to determine if they are appropriate for compressors outside this range. Further discussion related to DOE's selection of package isentropic efficiency as a metric can be found in section III.C.1.

For copies of the EU Lot 31 draft regulation:

www.regulations.gov/contentStreamer?documentId=EERE-2013-BT-STD-0040-0031&disposition=attachment&contentType=pdf.

DOE notes that Scales Industrial Technologies commented that the scope should be limited to a narrower range of 80-125 psig, commenting that a narrower range may provide more meaningful results and have less effect on isentropic efficiency. (Scales Industrial Technologies, No. 0013, p. 4) While Scales Industrial Technologies may be correct that a narrower range would have less effect on isentropic efficiency, DOE concludes, based on the input of CAGI, Ingersoll Rand, Sullivan-Palatek, Sullair, and Atlas Copco, as well as the precedent established by the draft EU Lot 31 regulation, that isentropic efficiency can be considered comparable and meaningful beyond the 80 to 125 psig range.

5. Lubricant Presence

As discussed in section III.A.9, in this final rule DOE adopts the definition proposed in the energy conservation standards NOPR for lubricated compressor as one that introduces an auxiliary substance into the compression chamber during compression. In this final rule, DOE also defines lubricant-free compressor and auxiliary substance. In the test procedure NOPR, DOE did not propose limiting scope based on lubrication; as such, the proposed scope implicitly included both lubricated and lubricant-free compressors. 81 FR 27220 (May 5, 2016).

In response to DOE's proposal, Atlas Copco, CAGI, and Kaeser Compressors noted that other technology options that are outside the scope of the test procedure, such as turbo compressors, centrifugal compressors, and other styles of dynamic compressors, will present themselves as viable alternatives to lubricant-free compressors and are risks for unregulated product substitution. (EERE-2013-BT-STD-0040, Atlas Copco, Public Meeting Transcript, No. 0044 at p. 58) Furthermore, Kaeser Compressors noted that the draft EU standard for compressors excluded lubricant-free compressors due to the risk of product substitution and lack of available data. CAGI and Kaeser recommended that DOE exclude lubricant-free compressors so that the DOE can harmonize with the draft EU compressor standard's approach for lubricant-free compressors. (EERE-2013-BT-STD-0040, CAGI, No. 0052 at p. 12; EERE-2013-BT-STD-0040, Kaeser Compressors, No. 0053 at p. 1)

DOE agrees with comments made by Atlas Copco, CAGI, and Kaeser that there is a risk of product substitution to unregulated technologies, which do not have the burden of representing efficiency in accordance to the proposed test procedure. DOE acknowledges that, in effect, the inclusion of lubricant-free rotary compressors gives unregulated technologies a competitive advantage in the marketplace in that they are free to represent efficiency in a less burdensome fashion. DOE also acknowledges an argument made by CAGI, which point out that the shipments volume of lubricant-free rotary compressors and dynamic compressors are approximately equal, yet DOE excluded centrifugal compressors from the scope of the test procedure on the basis of low shipment volume. (EERE-2013-BT-STD-0040, CAGI, No. 0052 at p. 12) 81 FR 27220, 27228 (May 5, 2016).

DOE also received many comments related to the appropriateness and applicability of the variable-speed compressors test method and metric (part-load package isentropic efficiency) to lubricant-free compressors. In general, commenters expressed concern that many lubricant-free compressors are unable to operate at the 40 percent flow load point, and as such, suggested that the test procedure, as proposed in the test procedure NOPR is not appropriate or applicable to lubricant-free compressors. A full discussion of these comments and their relationship to scope is found in section III.C.1, which discusses, in the depth, the metric and load points proposed in the test procedure NOPR. As a result of the discussions provided in section III.C.1, DOE is limiting the scope of the test procedure final rule to lubricated compressors only.

6. Specialty-Purpose Compressors

In the test procedure NOPR, DOE made no specific scope exclusion for

what the compressor industry refers to as “customized” or “specialty-purpose” compressors. In response, DOE received many comments recommending that it expressly exclude specialty-purpose compressors from the scope of the test procedure. Additionally, many commenters suggested that DOE establish criteria to exclude customized compressors that are created by modifying a standard compressor.

Sullivan-Palatek commented that compressor products usually start with the basic package, but often substitute non-standard electric motors, controls or coolers and add numerous other options and features specified by the customer or required by the location in which the compressor is installed. (Sullivan-Palatek, No. 0007 at p. 22)

Sullair provided examples of custom requirements, such as sump heating, extra fans, and special marine applications for which motors have to be built (American Bureau of Shipping), and noted that these frequently increase package energy consumption. (Sullair, Public Meeting Transcript, No. 0016 at p. 113)

Atlas Copco commented that the test procedures proposed in the NOPR applied to both standard compressor packages and custom compressor packages, and the latter often have unusual combinations of ancillary equipment. Atlas Copco provided examples of custom equipment, including customized liquid cooling systems, drive systems, safety systems, filtration systems, dryers, heaters, and air receiver/surge tanks. Atlas Copco also noted that each type of customization can have a significant impact on the energy efficiency of the total compressor system. Ultimately, Atlas Copco suggested that applying the proposed test procedure to custom orders for compressor packages was unduly burdensome to conduct and inappropriate under section 343(a)(2) of EPCA. (Atlas Copco, No. 0009 at pp. 4-7)

To address the industry concerns over the testing of customized and specialty-purpose compressors, CAGI recommended that the list of ancillary equipment they provided (see section III.A.3.b and Table III.1) should exclude all options or modifications required to meet specific customer requirements or other codified standards where these options or modifications are made to an existing tested model and do not create in and of themselves a new model. Examples may include options or modifications required to meet hazardous locations, breathing air, marine environments, ambient conditions above 45 °C or below 0 °C, weather protection, etc. (CAGI, No. 0010, p. 4)

Sullair agreed with CAGI's recommendation and provided additional examples of custom requirements, including hazardous locations or corrosive environments (as specified by the standard known as Atmosphères Explosibles, or “ATEX”)

or issued by the American Petroleum Institute (“API”), the Mine Safety and Health Administration (“MSHA”), etc.), marine environments, alternate cooling methods (remote coolers, water cooled, closed loop cooling, etc.), ambient conditions exceeding 45 °C, ambient conditions below 5 °C, energy or heat recovery options, environmental protections (NEMA 4, IEC 65, etc.), and dimensional changes or enclosure modifications. (Sullair, No. 0006 at p. 8)

ATEX is the common industry phrasing for European Parliament and Council Directive 2014/34/EU of 26 February 2014, which governs equipment and protective systems intended for use in potentially explosive atmospheres. The term “ATEX” is a portmanteau of “atmosphères explosibles”, French for “explosive atmospheres.”

In its comments, Sullivan-Palatek strongly urged the DOE to limit testing and sampling to the basic package as defined by CAGI. It also recommended that DOE permit add-ons and alterations to basic packages so that specialty products offered to the end-user customer base in the past can continue in the future. (Sullivan-Palatek, No. 0007 at p. 4)

As discussed in sections III.A.3.b and III.E.3, DOE is incorporating CAGI's recommended list of equipment (with certain modifications) to define the minimum testing configuration for a compressor basic model. DOE believes that the incorporation of this recommendation effectively excludes, from the scope of the test procedure, customized or specialty-purpose equipment that is created by adding additional equipment to what the industry refers to as a standard or basic package compressor.

Based on DOE's interpretation of the comments described above, two additional concerns remain: (1) Specialty-purpose equipment that is created by modifying or replacing equipment on a standard package compressor, and (2) specialty-purpose equipment that is not a derivative of other standard equipment. However, DOE notes that the commenters provided no specific examples of specialty-purpose compressors that have been distributed in commerce, nor did they provide any direct or quantitative evidence that such compressors consume more energy and are more burdensome to test than their “general-purpose” counterparts (beyond noting that more models may need to be certified). Regardless, given the commenters' concerns, DOE performed research (using interested party comments as a starting point) to determine if any additional scope exclusions are warranted. Specifically, DOE was able to identify 10 applications and feature categories that could possibly be used to characterize specialty-purpose compressors in the compressor industry:

(1) Corrosive Environments

(2) Hazardous Environments (combustion and/or explosion risk)

(3) Extreme Temperatures

(4) Marine Environments

(5) Weather-protected

(6) Mining Environments

(7) Military Applications

(8) Food Service Applications

(9) Medical Air Applications

(10) Petroleum, Gas, and Chemical Applications

Given the concerns raised by commenters, DOE established three specific criteria to help determine if test procedure exclusions are warranted for each of the aforementioned applications and feature categories. A compressor category must meet all criteria to be considered for exclusion.

The first criterion, distinguishability, is that compressors under consideration must be able to be distinguished from general-purpose compressors. In this case, to be distinguishable extends beyond being able to identify any difference whatsoever. Specifically, distinguishability is determined in the context of the test procedure. DOE's test procedure final rule contains instructions regarding compressor configuration during testing. During a test, only specific components are required to be connected; manufacturers may remove non-required components at their option. If the specialized nature of a compressor arises from a non-required component, manufacturers have the option to remove its influence on compressor performance. In that scenario, the specialty compressor, from the perspective of the test procedure, has collapsed to a general-purpose unit with no remaining distinction. In considering whether a compressor meets the distinguishability criterion, DOE will assess whether the specialized nature of the compressor arises from components or configurations that are removable or reconfigurable under the specific provisions of DOE's test.

As stated previously, DOE is incorporating CAGI's recommended list of equipment (with certain modifications), so the only specialty-

purpose compressors that could warrant exclusion are those that are created by modifying or replacing equipment on a standard package compressor, and specialty-purpose equipment that is not derivative of other standard equipment.

Under the second criterion, manufacturers must currently make public representations for the specific category of compressors using test procedure metrics. This criterion establishes the need to use the test procedure for the specific category. Absent an energy conservation standard, the test procedure is needed only to measure metrics used in representations of compressor performance. If manufacturers make no representations for a specific category of compressors, the existence of a test procedure has no impact on them. Sullivan-Palatek commented that manufacturers typically do not publish CAGI datasheets for models that are variations of a basic package. (Sullivan-Palatek, No. 0007 at p.4) This suggests that it is rare for manufacturers to make public representations of the performance for specialty-purpose compressors.

The third criterion is that it must be impractical to apply the test procedure to compressors in the specific category, because an attribute of the compressor renders testing technically impossible or possible only with major modification, or because the test procedure produces non-representative results for the specific category of compressor. This criterion establishes that there is a technical impediment to using the test procedure with the specific category of compressors.

DOE performed research, using publicly available data, on each of the categories to determine if exclusions are warranted. In the following paragraphs, DOE discusses findings for each of the aforementioned ten specialty applications.

Corrosive Environments

Corrosive environments can be damaging to both the external components of a compressor and the internal components, if corrosive agents are ingested with the air. DOE's research indicated that corrosive agents are found in a wide range of varieties and severities. Certain corrosive agents may harm some materials but not others.

Compressors may be adapted to corrosive environments by using special materials, having special coatings, using additional intake air filtration, or using special or remote enclosures to isolate the compressor from the corrosive environment. However, most requirements for corrosive environments are customer-specific, making it difficult to create a generalized scope exclusion. Some end users also use general-purpose compressors in a corrosive environment, opting to replace the compressor at an earlier interval instead of purchasing a more expensive compressor that can last longer in the corrosive environment.

Based on this information, DOE does not believe that all corrosive environment compressors meet the first criterion of distinguishability; however certain corrosive environment compressors utilizing special materials and/or coatings may be distinguishable.

DOE did not find any public representations of the performance for compressors designed for corrosive environments, suggesting that representations are not commonly posted.

Finally, DOE found no evidence that testing with the test procedure is impractical for compressors designed for corrosive environments, because these compressors operate in the same manner as general-purpose compressors.

Therefore, because manufacturers do not appear to make representations of performance for these compressors and there is no technical impediment to testing these compressors with the test procedure, DOE finds no cause to exclude compressors adapted to corrosive environments from the scope of this final rule.

Hazardous Environments

Hazardous environments include those in which there is the possibility of combustion or explosion. Compressors may be adapted to hazardous environments through modified electrical components and enclosures that protect against sparks and high temperatures. At least some of these components need to be included as part of the basic package during testing. Several standards specify the type and level of precautions required for these environments, so certification with one or more of these could be a method for defining the scope of exclusion.

For these reasons, DOE finds that hazardous environment compressors meet the first criterion of distinguishability. Hazardous environment compressors are designated as such by independent agencies such as UL, and given a rating that corresponds to the specific attributes of the hazardous environment for which the unit is being certified.

DOE did not find any public representations of the performance for compressors designed for hazardous environments, suggesting that representations are not commonly posted.

Finally, DOE found no evidence that testing with the test procedure is impractical for compressors designed for hazardous environments, because these compressors operate in the same manner as general-purpose compressors.

Therefore, because manufacturers do not appear to make representations of performance for these compressors and there is no technical impediment to testing these compressors with the test procedure, DOE finds no cause to exclude compressors adapted to operate in hazardous environments from the scope of this final rule.

Extreme Temperatures

CAGI and Sullair identified the need to exclude compressors used in extreme temperatures. (CAGI, No. 0010, p. 4; Sullair, No. 0006 at p. 8) For high-temperature extremes, both commenters identified temperatures above 45 °C. For low-temperature extremes, Sullair indicated temperatures below 5 °C, while CAGI indicated temperatures below 0 °C. DOE notes that CAGI and Sullair did not present any standardized tests or inspections that might be used to uniformly classify a non-extreme temperature range for compressors.

In the absence of that information, DOE performed research and found neither industry-accepted, standardized test methods to determine allowable operating temperature, nor any industry-accepted certification programs to classify compressors for extreme temperatures. DOE also researched what types of modification and components might be employed to adapt compressors for extremely high- and low-temperature environments. For lower temperatures, a variety of heating devices may be used to heat the compressor package in various ways—such equipment is not required as a part of test procedure testing configuration and is, therefore, not a distinguishing feature.

In hotter environments, compressors may employ larger output air heat exchangers and associated fans. Unlike package heating and cooling, heat exchangers and fans are part of the test configuration. However, manufacturers may employ larger heat exchangers and fans for a variety of reasons,

e.g.

recovering waste heat for use in space heating. Furthermore, heat exchanger and fan size (as compared to compressor capacity) is not a standardized feature across the compressor industry, with different manufacturers choosing different-sized components to meet their specific design goals. Consequently, DOE is unable to establish a clear threshold to delineate larger heat exchangers and fans employed for high

temperature applications. Furthermore, doing so opens a significant circumvention risk, as manufacturers could purposely substitute larger heat exchangers and fans in order to exclude compressors from regulation. For these reasons, DOE concludes that compressors designed for extreme temperature operation are not clearly distinguishable from general-purpose compressors.

DOE also did not find any public representations of the performance for compressors designed for extreme temperatures, suggesting that representations are not commonly posted.

Finally, DOE found no evidence that testing with the test procedure is impractical for compressors designed for extreme temperatures, because these compressors operate in the same manner as general-purpose compressors.

Therefore, because (a) it is difficult to clearly identify compressors for extreme temperatures; (b) manufacturers do not appear to make representations of performance for these compressors; and (c) there is no technical impediment to testing these compressors with the test procedure, DOE does not find cause to exclude compressors adapted to extreme temperatures from the scope of this final rule.

Marine Environments

Marine air compressors are intended for use aboard ships, offshore platforms, and similar environments. In general, DOE found this to be a very broad category of compressors. There are a wide variety of standards for these applications, but many of the requirements are customer-specific, making it difficult to clearly identify the scope for exclusion. Marine compressors may be space constrained if installed on ships. However, this may not always be the case, and some marine environments may be able to utilize general-purpose compressors. Further, DOE found no way to clearly distinguish, from general-purpose compressors, those that are specifically developed for constrained spaces. DOE's research found that other items, such as saltwater coolers, may be employed on marine air compressors, however, this equipment does not need to be included for testing. For these reasons, DOE does not find marine environment compressors to meet the first criterion of distinguishability.

DOE did not find any public representations of the performance for compressors designed for marine environments, suggesting that representations are not commonly made.

Finally, DOE found no evidence that testing with the test procedure is impractical for compressors designed for marine environments, because these compressors operate in the same manner as general-purpose compressors.

Therefore, because (a) it is difficult to clearly identify compressors for marine environments; (b) manufacturers do not appear to make representations of performance for these compressors; and (c) there is no technical impediment to testing these compressors with the test procedure, DOE does not find cause to exclude compressors adapted to marine environments from the scope of this final rule.

Weather-Protected

Weather-protected compressors require features to prevent the ingress of water and debris, as well as accommodation for extreme temperatures in some cases. DOE found that third-party standards exist for ingress protection of the electrical components. However, DOE did not find an indication of a standard or certification for other aspects of weather protection, making it difficult to clearly identify a general scope for exclusion for all weather-protected equipment. However, DOE believes that certain weather-protected compressors (

i.e.,

those with electrical components rated for ingress protection) meet the first criterion of distinguishability.

DOE did not find any public representations of the performance for weather-protected compressors, suggesting that representations are not commonly posted.

Finally, DOE found no evidence that testing with the test procedure is impractical for weather-protected compressors, because these compressors operate in the same manner as general-purpose compressors.

Mining Environments

Mining environments can include both surface and subsurface mine compressor applications. There are some standards for these applications, but many of the requirements are customer-specific, making it difficult to clearly identify the scope for exclusion. Some mining applications also use general-purpose compressors. For this reason, DOE does not find mining environment compressors to meet the first criterion of distinguishability.

DOE did not find any public representations of the performance for compressors designed for mining environments, suggesting that representations are not commonly posted.

Finally, DOE found no evidence that testing with the test procedure is impractical for compressors designed for mining environments, because these compressors operate in the same manner as general-purpose compressors.

Therefore, because (a) it is difficult to clearly identify compressors designed for mining environments; (b) manufacturers do not appear to make representations of performance for these compressors; and (c) there is no technical impediment to testing these compressors with the test procedure, DOE does not find cause to exclude compressors designed for mining environments from the scope of this final rule.

Military Applications

Compressors used in military applications have a wide range of applications. Many military applications use common commercial or industrial compressors. Other military applications, however, must meet extensive customer-specific requirements. These requirements can vary greatly with the customer, and there are no commonly used standards for compressors in military applications. This makes it difficult to clearly identify the scope for exclusion. For this reason, DOE does not find military compressors to meet the first criterion of distinguishability.

DOE did not find any public representations of the performance for compressors designed for military applications, suggesting that representations are not commonly posted.

Finally, DOE found no evidence that testing with the test procedure is impractical for compressors designed for military applications, because these compressors operate in the same manner as general-purpose compressors.

Therefore, because (a) it is difficult to clearly identify compressors designed for military applications; (b) manufacturers do not appear to make representations of performance for these compressors; and (c) there is no technical impediment to testing these compressors with the test procedure, DOE does not find cause to exclude compressors designed for military applications from the scope of this final rule.

Food Service Applications

Food service applications can have requirements for air purity and to use food-grade lubricants. Food grade lubricants need to be included for testing, so at least some compressors designed for food service applications meet the first criterion of distinguishability.

DOE did not find any public representations of the performance for compressors designed for food service applications, suggesting that representations are not commonly posted.

Finally, DOE found no evidence that testing with the test procedure is impractical for compressors designed for food service applications, because these compressors operate in the same manner as general-purpose compressors.

Medical Air Applications

Medical air applications can have requirements for air purity, which is both rated according to ISO 8573-1 and included in the National Fire Protection Association Standard for Health Care Facilities (NFPA 99). DOE notes that most medical air compressors are lubricant-free and, as such, are already excluded from this final rule. In lubricated compressors, high air purity is attained using a combination of filters and dryers added to the system downstream of the compressor discharge. These items are outside the basic compressor package, so a medical air compressor collapses to a standard basic package for testing. For this reason, DOE does not find medical air application compressors to meet the first criterion of distinguishability.

DOE did not find any public representations of the performance for compressors designed for medical air applications, suggesting that representations are not commonly posted.

Finally, DOE found no evidence that testing with the test procedure is impractical for compressors designed for medical air applications, because these compressors operate in the same manner as general-purpose compressors.

Therefore, because (a) manufacturers do not appear to make representations of performance for compressors designed for medical air applications; (b) these compressors collapses to the basic package for testing; and (c) there is no technical impediment to testing these compressors with the test procedure, DOE does not find cause to exclude compressors designed for medical air applications from the scope of this final rule.

Petroleum, Gas, and Chemical Applications

The American Petroleum Institute standard 619, “Rotary-Type Positive-Displacement Compressors for Petroleum, Petrochemical, and Natural Gas Industries,” (API 619), specifies certain minimum requirements for compressors used in the petroleum, gas, and chemical industry. While API 619 contains many specific design requirements, it also indicates that customers must specify many design requirements themselves. As a result, compressors designed to meet API 619 requirements are not uniform; rather, they are, by definition, customized compressors. In addition to the design requirements, API 619 imposes rigorous testing, data reporting, and data retention requirements on manufacturers. For example, manufacturers are required to perform specific hydrostatic and operational mechanical vibration testing on each individual unit distributed in commerce. Furthermore, manufacturers must retain certain data for at least 20 years, such as certification of materials, test data and results, records of all heat treatment, results of quality control tests and inspections, and details of all repairs. Based on these testing, data reporting, and data retention requirements, DOE concludes that compressors designed and tested to the requirements of API 619 meet the first criterion of distinguishability.

Based on DOE's assessment of API 619, DOE believes that the minimum design and testing requirements specified in API 619 are created to achieve, among other goals, safety and reliability in the petroleum, gas, and chemical industry. These requirements ensure that the compressor can be operated and maintained safely, in the safety-critical petroleum, gas, and chemical industry. Thus, there is not a current industry test procedure that would apply and it is unclear if the methodology being adopted in this final rule would be representative of their actual use. Thus, DOE is declining to adopt a test procedure for compressors designed for petroleum, chemical and gas applications.

C. Metrics

1. Package Isentropic Efficiency

In the test procedure NOPR, DOE proposed “package isentropic efficiency” to be the energy metric for compressors, and defined package isentropic efficiency to mean the ratio of power required for an ideal isentropic compression process to the actual packaged compressor power input used at a given load point, as determined in accordance with the test procedures included in 10 CFR 431.344.

81 FR 27220, 27232 (May 5, 2016). Because package isentropic efficiency is expressed relative to an ideal isentropic process between the same input and output pressures, it could therefore be used to compare units across a wide range of pressures. DOE presented this applicability across a wide range of pressures as an advantage of package isentropic efficiency over specific input power.

Ibid.

Test methods are discussed specifically in section III.E.

Specifically, DOE proposed to establish two versions of package isentropic efficiency: Full-load package isentropic efficiency and part-load package isentropic efficiency. DOE proposed that full-load package isentropic efficiency would apply only to fixed-speed compressors, whereas part-load package isentropic efficiency would apply only to variable-speed compressors. Full-load package isentropic efficiency is evaluated at a single load point, while part-load package isentropic efficiency is a weighted composite of performance at multiple load points (or rating points). Equation 1 and Equation 2 describe the full- and part-load package isentropic efficiency, as proposed in the test procedure NOPR.

ER04JA17.000

Where:

isen,FL

= package isentropic efficiency at full-load operating pressure,

isen,100≠

= isentropic power required for compression at full-load operating pressure, and

real,100≠

= packaged compressor power input at full-load operating pressure.

ER04JA17.001

Where:

isen,PL

= part-load package isentropic efficiency,

= weighting factor for rating point i,

isen,i

= isentropic power required for compression at rating point i,

real,i

= packaged compressor power input at rating point i, and

i = load points at 100, 70, and 40 percent of full-load actual volume flow rate.

To clearly separate the two varieties of compressors, in the test procedure NOPR, DOE proposed the following definitions for fixed-speed and variable-speed compressors:

Fixed-speed compressor

means an air compressor that is not capable of adjusting the speed of the driver continuously over the driver operating speed range in response to incremental changes in the required compressor flow rate.

Variable-speed compressor

means an air compressor that is capable of adjusting the speed of the driver continuously over the driver operating speed range in response to incremental changes in the required compressor actual volume flow rate.

DOE received a significant volume of comments regarding these metrics, associated load points and weights, and the applicability of each version of package isentropic efficiency. The following subsections discuss these issues and relevant comments in detail.

a. Use of Full-Load and Part-Load Package Isentropic Efficiency as Regulatory Metrics

In response to DOE's proposal to use package isentropic efficiency as a metric, CASTAIR disagreed, stating that air compressors consume electricity (in kW, using electric motors that are already regulated) and produce flow (in cfm). CASTAIR further stated that power (in kW) and flow (in cfm) are very easy things to test and record, and suggested that DOE should then regulate, if it must, the efficiency between the two (

i.e.,

kW and cfm) for air ends. (CASTAIR, No. 0018 at p. 1) Based on this comment, DOE interprets that CASTAIR is suggesting that the efficiency of the compressor should be a simple calculation based on the regulated representation of efficiency for the electric motor and the airflow produced by the air compressor. In response to this suggestion, DOE clarifies that the efficiency and energy consumption of an air compressor is not solely a function of the motor. As DOE discussed in the energy conservation standards NOPR, opportunities exist to select or design higher efficiency motors, drives (if applicable), bare compressors (including multi-staging), mechanical equipment, and ancillary equipment. 81 FR 31680, 31701-2 (May 19, 2016). For this reason, DOE concludes that the efficiency of the motor alone, even when coupled with the output airflow of the compressor, is not an appropriate metric to represent to energy efficiency or consumption of an air compressor.

Alternatively, DOE recognizes that CASTAIR may have been recommending a metric of the form of power (in kW) per unit flow (in cfm). DOE acknowledges that this general metric could properly characterize the typical energy use of an air compressor, if coupled with an appropriate test method. However, this ratio has a significant shortcoming as a regulatory metric. Specifically, achievable kW/cfm is a function of both pressure and flow, which means an energy conservation standard would need to be a function of both pressure and flow—a more complex determination as compared to package isentropic efficiency.

Thus, in this final rule, DOE concludes that a metric of the form kW/cfm introduces unnecessary complexity into any energy conservation standards that would rely on such a metric (

i.e.,

adding pressure as a second dependent characteristic).

For example, higher flow machines can naturally achieve a better kW/cfm score as maximum achievable motor and bare compressor efficiency increase with size and flow. Alternatively, lower pressure machines can naturally achieve a better kW/cfm score as less power is required to compress the same volume of air to a lower pressure.

With respect to metric selection, Atlas Copco asserted that DOE's method of calculating compressor energy use is flawed because, as a steady-state metric, it lacks a means to compare in-operation energy savings of compressors with different operating profiles. Atlas Copco further asserted that DOE failed to use a methodology to calculate the performance of an air compressor at part-load, and failed to take into account energy losses due to the cyclic operations. Cyclic operations, commented Atlas Copco, are responsible for an additional vast amount of energy required without delivering any useful air and should be accounted for to understand cyclic demands required for certain applications. (Docket No. EERE-2013-BT-STD-0040, Atlas Copco, No. 0054 at p. 9; Atlas Copco, No. 0009 at pp. 13-14)

Atlas Copco suggested an alternative metric that considers energy consumption during loaded operation, unloaded operation, and the transient in-between. Specifically, Atlas Copco suggested a metric that calculates the energy consumption for one running hour and the accumulated useful volume of air which is delivered to the customer. Based on these values, the corresponding overall Specific Energy Requirement (SER) can be calculated, which can be converted to the isentropic efficiency. Atlas Copco went on to specifically define SER as the energy consumed during one hour of operation, divided by the useful volume of air produced during this time period, and provided an equation to convert SER to isentropic efficiency. Atlas Copco stated that these metrics reflect the true energy consumption and would allow customers to compare all compressor technologies on an apples-to-apples basis. It also stated that such metrics would provide a method to assess the part-load performance of variable-speed machines that cannot reach the 40-percent load point rather than allowing the compressor to test at the minimum achievable flow point, which unfairly penalizes large turndown variable-speed compressors. (Atlas Copco, No. 0009 at p. 12-13; Atlas Copco, No. 0009 at p. 15; Docket No. EERE-2013-BT-STD-0040, Atlas Copco, No. 0054 at pp. 9-11)

In its comments, Atlas Copco suggests that the energy consumption during one hour of operation can be calculated as the sum of the energy consumed during loaded and unloaded operation (which can be measured using ISO 1217:2009(E)), as well as the “cycle energy requirement.” Atlas Copco

defines the cycle energy requirement as the total energy required for fully pressurizing the internals of the compressor package starting from idle regime until useful air delivery, summed with the full venting of the same internals starting from the end of useful air delivery until idle regime;

i.e.,

the energy consumed during transient operation between the loaded and unloaded state. Atlas Copco goes on to provide a suggested measurement procedure for the determination of cycle energy losses. (Atlas Copco, No. 0009 at pp. 13-14; Atlas Copco, Annex A, No. 0009 at pp. 3-13; Docket No. EERE-2013-BT-STD-0040, Atlas Copco, No. 0054 at p. 9-11) Further, Atlas Copco suggested that DOE establish separate regulations for the fixed flow profile and the variable flow profile, but to also have all machines list values for both. (Atlas Copco, No. 0009 at p. 11; Atlas Copco, No. 0009 at p. 15) Given Atlas Copco's suggestion to use a new metric, DOE is unclear what values Atlas Copco is referring to when it suggests that DOE list “both.” DOE is unclear whether Atlas Copco supports the use of its new metrics (SER and its associated isentropic efficiency) as the exclusive metrics for compressors, or if Atlas Copco is suggesting that the new metrics be used in addition to the DOE-proposed part-load and full-load package isentropic efficiency.

Sullair agreed that although measurements and efficiency standards for part-load operation of fixed-speed compressors may be useful, no standard has been established, tested, or proven to measure compressor performance across all fixed-speed control methods (modulation, load-unload, variable displacement, etc.) employed by various manufacturers. As a result, Sullair commented that it did not support a part-load test procedure for fixed-speed compressors at this time. Sullair noted that preliminary work is being done by CAGI to measure one of these control methods (variable displacement) and supported further development of a test procedure or metric across multiple manufacturers and control types prior to adoption by DOE. (Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at pp. 16-17)

Sullair cited that the variable-speed, part-load performance data used to develop both the EU Lot 31 draft standard and the proposed DOE standard came from CAGI's Performance Verification Program, which was gathered over the span of nearly 10 years. In contrast, Sullair argued that to rush development of a new test method and metric for part-load measurement of fixed-speed compressors, without support from the industry or verified supporting data from multiple manufacturers and units, would be rash and inappropriate. Sullair anticipated that such a development risks unintended consequences that may negatively impact the compressor industry, compressor consumers, and U.S. industry at-large. (Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at pp. 16-17)

Sullair concluded that, primarily because of a lack of verified data and an agreed upon industry test standard for all fixed-speed control types, DOE should proceed with its proposal to classify compressors as fixed-speed or variable-speed, and limit part-load testing to variable-speed compressors. (Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at pp. 16-17)

In agreement with Sullair, DOE acknowledges that a package isentropic efficiency metric that includes cycle losses (as recommended by Atlas Copco) could acceptably represent the typical energy use of compressors. However, as discussed in Sullair's comment, the use of cycle losses and the test and calculation methods recommended by Atlas Copco represent the opinions and findings of one industry participant, and do not represent an industry accepted metric or test method. Atlas Copco has not presented evidence that these methods and accompanying results have been validated or peer reviewed outside of Atlas Copco's organization. Further, DOE believes that the use of Atlas Copco's suggested metric and cycle loss test method is likely to increase the burden on manufacturers as it appears to require additional testing beyond what was proposed in the test procedure NOPR. Furthermore, the industry (outside of Atlas Copco) is unfamiliar with the additional testing that would be required. Finally, no historical performance data exists for the metric proposed by Atlas Copco, which makes it a poor choice for a regulatory metric at this time. Without historical performance data for the Atlas Copco metric, DOE would be unable to establish baseline and maximum technologically feasible efficiency levels, and would be unable to complete any of the analyses required to assess and establish energy conservation standards.

Alternatively, given the general support of CAGI, Sullivan-Palatek, Ingersoll Rand, and Sullair for items on which they did not directly comment on, DOE believes that full-load package isentropic efficiency represents an industry-accepted metric, which is backed by an industry-accepted test method (ISO 1217:2009(E), as amended), and has a large cache of reliable industry test data. (CAGI, No. 0010 at p. 3, Sullivan-Palatek, No. 0007 at p. 1; Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1) The use of full-load package isentropic efficiency in the EU Lot 31 draft standard further indicates that this metric is an appropriate and industry-accepted metric for the assessment of fixed-speed compressors. In summary, DOE again acknowledges that Atlas Copco's suggested metric, which incorporates part-load cycle losses, may acceptably represent the typical energy use of compressors, however for the reasons discussed in this section, DOE concludes that, at this time, it is not an appropriate metric to adopt. If this metric gains acceptance in the industry and the test method can be formalized and validated beyond a case study, DOE may consider incorporating such a method in future rulemakings.

With respect to Atlas Copco's suggestion that each compressor be labeled with scores from two metrics, DOE notes the core purpose of a Federal test procedure is to establish test methods to evaluate equipment against the applicable energy conservation standards. If DOE were to require the listing of two metrics on each compressor, DOE must require that each compressor test to two test methods. Requiring such testing and reporting would represent an incremental burden beyond what DOE proposed in the test procedure NOPR. In general, DOE strives to minimize the incremental burden of any test procedures rulemaking. Therefore, in this test procedure final rule, DOE does not adopt any mandatory testing or reporting beyond the metrics proposed in the test procedure NOPR.

Similarly to Atlas Copco, the CA IOUs suggested that, for fixed-speed compressors with either “start/stop,” or “load/unload” controls, the air flow and power consumption should be tested to capture energy consumption at full-load and fully unloaded. They also suggested that fixed-speed compressors with “load/unload” controls be tested to measure the duration of the purge cycle (time it takes to achieve fully unloaded power—also known as blowdown time), as this data can be mathematically combined with the airflow and power consumption data at full-load and fully unloaded to estimate the compressor's efficiency at various points between full-load and fully unloaded. (CA IOUs, No. 0012 at p. 1-2) Unlike Atlas Copco, the CA IOUs suggest that this data be measured and reported as supplemental information, rather than incorporated into a new metric.

While DOE agrees that information describing unloaded and transition states of operation could be useful to the end user, the CA IOUs' recommendation represents testing and reporting that is not essential to the output of the test procedures; requiring such testing and reporting would represent an incremental burden beyond what DOE proposed in the test procedure NOPR. In general, DOE strives to minimize the incremental burden of any test procedures rulemaking. Therefore, in this test procedure final rule, DOE is not adopting any mandatory testing or reporting of no-load power. Manufacturers may measure and advertise no-load power and blowdown time, and DOE may further explore no-load power measurement and reporting requirements in a future rulemaking.

CAGI also argued for the importance of considering operating conditions in determining efficiency. CAGI commented that, because field variables were a large determinant of system efficiency, any value assigned to package efficiency may be misleading to consumers. (Docket No. EERE-2012-BT-DET-0033, CAGI, No. 0003 at p. 8)

In response to CAGI's comment, DOE is not representing package isentropic efficiency as a substitute for consideration of site-specific operating factors. Rather, it is intended to serve as a common basis for comparison between compressors.

Atlas Copco suggested that low-pressure air and lubricant-free compressors have their package isentropic efficiencies expressed as a function of discharge pressure in addition to flow rate, noting that full-load operating pressure is a significant variable that affects package isentropic efficiency for those compressor configurations. (Atlas Copco, No. 0009 at p. 15; Atlas Copco, Public Meeting Transcript, No. 0016 at pp. 41-42; EERE-2013-BT-STD-0040, Atlas Copco, No. 0054 at pp. 19-20) As discussed in sections III.B, DOE is narrowing the scope of this test procedure final rule to a smaller pressure range, which only includes lubricated compressors. This revised scope matches the range over which the dependency of isentropic efficiency on discharge pressure is described by CAGI as limited. Therefore, DOE concludes that the changes to the proposed metric, recommended by Atlas Copco, are not necessary. However, DOE may consider adding a pressure-dependent term, should it choose to pursue to test procedures or energy conservation standards for lubricant-free equipment or equipment outside of the 75-200 psig range in future rulemakings.

Scales Industrial Technologies agreed that the package isentropic efficiency metric is a good measurement, but commented that the metric is not common in industry. Scales Industrial Technologies suggested instead to use specific power, as it has been the industry-accepted expression of compressor efficiency. (Scales Industrial Technologies, No. 0013 at p. 4)

In response, DOE acknowledges that package isentropic efficiency is not as commonly used as specific power. However, based on the general support of other commenters for package isentropic efficiency, its use in the analogous EU Lot 31 draft standard, and its pressure independence over the scope being established in this final rule, DOE concludes that package isentropic efficiency is the most appropriate metric for describing the energy performance of compressors within the scope of this test procedure.

b. Load Points Selection and Applicability

As shown in Equation 1 and Equation 2 in the test procedure NOPR, DOE proposed that fixed-speed units be tested at a single load point, the full-load actual volume flow rate; and that variable-speed units be tested at three load points: 100, 70, and 40 percent of full-load actual volume flow rate. 81 FR 27220, 27232-4 (May 5, 2016).

In response, ASAP and NEEA generally supported DOE's proposed load points for full-load and part-load package isentropic efficiency. (ASAP and NEEA, No. 0015 at p. 2) Kaeser Compressors also supported the selection of load points that harmonized with the EU Lot 31 draft standard. (Kaeser Compressors, Public Meeting Transcript, No. 0016 at p. 63) Alternatively, the CA IOUs suggested that variable-speed compressors be tested at a minimum of six test points (excluding a no load power test point), in alignment with the CAGI Performance Verification Program test procedure, and also use a minimum volume flow rate no higher than 40 percent of the maximum volume flow rate to avoid possible loopholes. (CA IOUs, No. 0012 at p. 3)

With respect to the smallest flow rate load point for variable-speed compressors, CAGI noted that not all variable-speed compressors can reach a speed that achieves 40 percent of full-load actual volume flow rate, as minimum speeds can be limited by technical considerations such as bearing speeds, overheating, motor current, etc. (CAGI, Public Meeting Transcript, No. 0016 at p. 60) Kaeser Compressors and Sullair supported CAGI's remark, while Sullair continued to state that this is especially important for lubricant-free compressors due to technical limitations that keep them from running at speeds as low as 40 percent of [full] flow. (Sullair, Public Meeting Transcript, No. 0016 at p. 64) Kaeser Compressors added that, among other reasons, EU Lot 31 draft standard can set a 40-percent load point because it does not include lubricant-free compressors. (Kaeser Compressors, Public Meeting Transcript, No. 0016 at pp. 64-5) In response to this concern, CAGI suggested that the lower load point should be at 40 percent flow or the manufacturer's minimum stated capacity, if greater. (CAGI, No. 0010 at p. 6) Sullair supported CAGI's comments. (Sullair, Public Meeting Transcript, No. 0016 at p. 64)

Atlas Copco commented that a provision that permits manufacturers to test at the manufacturer's stated minimum speed if a compressor cannot achieve the 40-percent load point would penalize compressor packages with large turndown ratios. (Atlas Copco, No. 0009 at p. 12-13) Atlas Copco further clarified that the disadvantage to larger turndown machines results from the higher average efficiency achieved by testing at a load point greater than 40 percent, which results in a higher average weighted isentropic efficiency. (Atlas Copco, Public Meeting Transcript, No. 0016 at p. 60) DOE notes in this statement that Atlas Copco has incorrectly quoted the test procedure NOPR, in which DOE made no mention of how to test a variable-speed compressor for which the 40-percent load point is unachievable due to technical limitations. Atlas Copco went on to suggest that compressors that cannot reach the 40-percent load point should instead be allowed to use the SER metric, which is discussed in section III.C.1.a. (Atlas Copco, No. 0009 at p. 11) Atlas Copco further commented that the draft EU compressor standard included no load power as a reported metric, allowing for a more complete picture of efficiency when a variable-speed compressor is used at flow rates below the manufacturer's minimum flow rate. (Atlas Copco, Public Meeting Transcript, No. 0016 at pp. 69-70)

Similar to Atlas Copco, Kaeser Compressors noted that there would be efficiency gains in testing at flow rates greater than 40 percent, but that there would also be market disadvantages because the unit would seem less flexible, and so there would be little incentive for manufacturers to declare relatively high flow rates. For that reason, Kaeser therefore suggested that main issue with the 40-percent load

point was not the possibility of manufacturers artificially increasing efficiency ratings, but instead the fact that lubricant-free compressors may not be able to reach that flow rate. (Kaeser Compressors, Public Meeting Transcript, No. 0016 at pp. 65-6) Sullair stated that manufacturers would lose marketability if they rated the unit at a greater minimum flow rate to gain efficiency, because the primary benefit of variable-speed compressors is to allow control over a wide range of flow rates. (Sullair, Public Meeting Transcript, No. 0016 at p. 66) Likewise, ASAP, ACEEE, NEEA, NRDC, NEEP, and ASE did not support the CAGI proposal of using a lower load point of 40 percent or manufacturer minimum as it inflates efficiency ratings for compressors that cannot reach 40 percent and suggested that DOE work with CAGI to develop an alternative minimum test for compressors. (EERE-2013-BT-STD-0040, ASAP, ACEEE, NEEA, NRDC, NEEP, ASE, No. 0060 at p. 4)

In response to comments on the 40-percent load point, DOE reviewed all available CAGI Performance Verification Program data sheets for lubricant-free variable-speed compressors, and concurs with the concerns raised by industry that not all lubricant-free variable-speed compressors can achieve the 40-percent load point. Specifically, DOE found that 65 percent of CAGI data sheets for lubricant-free compressors were rated with a minimum flow greater than 40 percent of maximum flow.

DOE considers this data, in conjunction with the previously referenced comments, as clear evidence that the proposed test procedure load points do not apply to variable-speed lubricant-free compressors due to the technical limitations in the turndown ratio of such equipment. Further, DOE concludes that because of these technical limitations and other significant technological differences between lubricated and lubricant-free compressors, separate test methods and metrics may be required for each. In addition, the European Commission is exploring specific standards and test methods for lubricant-free compressors, but has not released a draft proposal of its standard. Based on the comments discussed in this section, DOE concludes that significant work is required to establish an acceptable test method specific to lubricant-free compressors, and that the most efficient path to establishing an acceptable test method for lubricant-free compressors is to monitor and, possibly, collaborate with the European Commission as its own work progresses. DOE may pursue a test procedure for lubricant-free equipment in a separate rulemaking, but is not including lubricant-free compressors in the scope of this test procedure final rule.

For lubricated compressors, DOE found that 16 percent of CAGI data sheets were rated with a minimum flow greater than 40 percent of maximum flow. These results indicate that 84 percent of lubricated variable-speed compressors are able to achieve the 40-percent load point.

DOE agrees with Atlas Copco that allowing those few lubricated variable-speed compressors that cannot achieve 40 percent flow to test using the minimum achievable flow as an alternative to the 40-percent load point would penalize high-turndown machines. Such penalization would occur because the package isentropic efficiency of a variable-speed compressor typically decreases as flow (

i.e.,

load) decreases. To confirm this, DOE reviewed available CAGI Performance Verification Program data sheets and found that for 82 percent of the rotary lubricated variable-speed models, the package isentropic efficiency at 40 percent of full-load actual volume flow rate was lower than the package isentropic efficiency at 70 percent of full-load actual volume flow rate.

Given this relationship between package isentropic efficiency and flow rate, a compressor's package isentropic efficiency (as proposed in the test procedure NOPR) would typically increase by replacing the 40-percent load point with a load point at a higher flow.

Not all units reported performance at 40 percent and 70 percent of full-load actual volume flow rate. In those cases, DOE generated estimates for those points using interpolation from surrounding data points.

Given this information, DOE has two major concerns with CAGI's recommendation. First, CAGI's recommended method would not result in a fair and equitable efficiency metric. For example, given two compressors with the same full-load actual volume flow rate and full-load package isentropic efficiency, one with a manufacturer-specified minimum flow rate of 40 percent of full-load actual volume flow rate and one with a manufacturer-specified minimum flow rate of 70 percent of full-load actual volume flow rate, the latter would usually test at a better part-load package isentropic efficiency, even though the former provides more utility to the end user and has the potential to use less energy.

Second, CAGI's recommended method relies on a “manufacturer's minimum stated capacity,” and creates a significant opportunity for loopholes. For example, if a given variable-speed compressor does not meet the established energy conservation standard, a manufacturer may be able to restate its minimum capacity at a larger value and retest the model. Because package isentropic efficiency is typically greater at the rerated higher capacity, the manufacturer may be able to pass the standard with the rerated value. The result of this example directly conflicts with the intent of an energy conservation standard, because the resulting compressor offers reduced utility to the end user and may even consume more energy than it would with a lower stated minimum capacity.

Consequently, in this final rule, DOE rejects CAGI's recommendation to use the manufacturer's minimum stated capacity for variable-speed compressors if the compressor cannot achieve the 40-percent load point.

DOE concludes that the amount to which a variable-speed lubricated compressor can turn down is a distinct end user utility. Both Sullair and Kaeser Compressors clearly noted similar assertions that the speed and flow to which a variable-speed compressor can turn down is a distinct utility to the end user. (Sullair, Public Meeting Transcript, No. 0016 at p. 66; Kaeser Compressors, Public Meeting Transcript, No. 0016 at pp. 65-6)

DOE also concludes, based on previously mentioned data analysis as well as comments from Kaeser Compressors and Sullair (Sullair, Public Meeting Transcript, No. 0016 at p. 67; Kaeser Compressors, Public Meeting Transcript, No. 0016 at pp. 67-8), that for lubricated variable-speed compressors within the scope of this final rule, the majority of lubricated compressors are able to reach the 40-percent load point;

i.e.,

turning down to 40 percent of flow is technologically feasible for all pressures, flows, and horsepower of compressors within the scope of this final rule.

Consequently, DOE concludes that it is appropriate that the test method for variable-speed lubricated compressors require that a tested compressor reach each flow point because the part-load package isentropic efficiency metric is designed to align with the utility of the variable-speed compressors and must accurately represent their operation. For these reasons, DOE is adopting the methodology as proposed in the NOPR, which requires testing at the 40-percent load point. If a manufacturer has a basic model which is incapable of operating at the 40-percent load point, the manufacturer must seek a waiver from

the test procedure to obtain an alternative method of test from the Department pursuant to 10 CFR 431.401. As part of the test procedure waiver application, DOE would examine the details of the variable-speed compressor's performance curve (

e.g.,

the package isentropic efficiency over the range of available driver speeds for which the compressor is capable of operating) in order to determine the correct testing points and weightings for regulatory purposes. Since these could be different for each basic model, DOE believes it is best to determine the details on a basic model basis, rather than adopting a blanket approach of the manufacturer's specified minimum as suggested by CAGI. This would allow DOE to ensure fair and equitable ratings and not disadvantage those compressors that operate at lower speeds. This approach ensures that all compressors rated with the part-load package isentropic efficiency metric provide comparable utility to the end user, and that any compressors requiring a waiver would use a modified metric that reflects the reduction in utility resulting from their restricted range of flow rates.

DOE's regulations set forth at 10 CFR 431.401 contain provisions that permit a person to seek a waiver from the test procedure requirements for covered equipment if at least one of the following conditions is met: (1) The basic model contains one or more design characteristics that prevent testing according to the prescribed test procedures; or (2) the prescribed test procedures may evaluate the basic model in a manner so unrepresentative of its true energy consumption as to provide materially inaccurate comparative data. 10 CFR 431.401(a)(1) A petitioner must include in its petition any alternate test procedures known to the petitioner to evaluate the basic model in a manner representative of its energy consumption. 10 CFR 431.401(b)(1)(iii) DOE may grant a waiver subject to conditions, including adherence to alternate test procedures. 10 CFR 431.401(f)(2)

For the case of variable-speed compressors that cannot reduce flow to the 40-percent load point, DOE may grant a waiver using a modified test procedure that reflects the reduction in utility resulting from the compressor's restricted range of flow rates. The modified test procedure may calculate part-load package isentropic efficiency using a weighted average of the performance at full-load, the performance at the 70-percent load point (if the compressor can reach this load point), and the performance at the compressor's lowest load point. The weighted average may include modifications to reflect the reduction in utility resulting from the compressor's restricted range of flow rates. For example, the weighting may consider the typical change of efficiency with flow rate and may account for the increased energy required for the compressor to achieve the 70-percent and 40-percent load points by loading and unloading. DOE may determine the modified test procedure on a case-by-case basis, depending on the specific nature of the waiver request and the equipment construction.

Based on the preceding discussion, DOE concludes that no changes are needed in DOE's proposed definitions of fixed-speed compressor and variable-speed compressor. As a result, DOE is adopting the definitions of fixed-speed compressor and variable-speed compressor that it proposed in the test procedure NOPR.

With respect to the remaining load points (

i.e.,

100 and 70 percent for variable-speed and 100 percent for fixed-speed), DOE reiterates that Kaeser Compressors, ASAP, and NEEA supported DOE's test procedure NOPR. (Kaeser Compressors, Public Meeting Transcript, No. 0016 at p. 63; ASAP and NEEA, No. 0015 at p. 2) However, the CA IOUs disagreed and suggested that variable-speed compressors be tested at a minimum of six test points while utilizing a minimum volume flow rate no higher than 40 percent of the maximum volume flow rate to avoid possible loopholes. In response, DOE recognizes that the CA IOUs' recommendation aligns with the current CAGI Performance Verification Program testing method; however, DOE has two major concerns with CA IOUs' recommendation. First, the CA IOUs' recommended method would not result in a repeatable, fair, and equitable efficiency metric. For example, given two compressors with the same full-load actual volume flow rate and full-load package isentropic efficiency, one could be tested at six points (40, 50, 60, 70, 80, and 100 percent of full-load actual volume flow rate) and one could be tested at 10 points (40, 50, 60, 70, 80, 90, 92.5, 95, 97.5, and 100 percent of full-load actual volume flow rate). As previously discussed, due to the fact that package isentropic efficiency varies as a function of actual volume flow rate, the latter compressor, tested at 10 load points would likely achieve a different part-load package isentropic efficiency score (as in the test procedure NOPR) than the former compressor.

Similarly, the lack of firmly specified load points creates a significant opportunity for loopholes. For example, if a given variable-speed compressor does not meet the established energy conservation standard, a manufacturer may be able to retest with additional load points that are biased to the compressor's most efficient flow range and ultimately pass the standard with this rerated value. This directly conflicts with the intent of an energy conservation standard, as the resulting compressor still consumes the same amount of energy as it did before the retesting and rerating.

Due to these concerns with the CA IOUs' suggestion, the general support provided by CAGI, ASAP, and NEEA, and the reasons established in the test procedure NOPR, DOE is adopting the load points of 100, 70, and 40 percent of full-load actual volume flow rate for the part-load package isentropic efficiency metric, and 100 percent of full-load actual volume flow rate for the full-load package isentropic efficiency metric.

c. Metric Applicability

In response to the test procedure NOPR, the CA IOUs suggested that fixed-speed “inlet modulating”

and “variable displacement”

compressors (herein referred to as “fixed-speed variable-flow compressors”) should be tested at full-load and multiple part-loads in alignment with the CAGI Performance Verification Program test procedures for variable-speed compressors. According to the CA IOUs, this would provide valuable efficiency information for part-load conditions, which are common for fixed-speed compressors. (CA IOUs, No. 0012 at pp. 2) Similarly, ASAP and NEEA suggested that DOE require that fixed-speed compressors with controls that allow for variable airflows be tested in the same way as variable-speed compressors. ASAP and NEEA stated that this would facilitate the comparison between fixed-speed and variable-speed compressors

under part-load conditions. (ASAP and NEEA, No. 0015 at p. 2)

Inlet modulating compressors adjust the capacity of the compressor to the demand required by the system with a regulating valve on the inlet. The control system closes the inlet valve in response to a reduction in system demand, effectively throttling the compressor by reducing the inlet pressure and, consequently, the mass flow of air entering the compressor. (

http://www.cagi.org/requestinator_dl.aspx?txdata=L3BkZnMvQ0FHSV9FbGVjdEhCX2NoMi5wZGY=,

page 88).

Variable displacement compressors use a valve to divert a fraction of the inlet mass flow from the start of the rotor to an intermediate position of the compression system, reducing the effective length of the rotor but maintaining the inlet pressure and compression ratio. The valve is adjustable and responds to changes in discharge pressure. (

http://www.cagi.org/requestinator_dl.aspx?txdata=L3BkZnMvQ0FHSV9FbGVjdEhCX2NoMi5wZGY=,

page 88).

NEEA further commented that the efficiency metrics are appropriate for comparing variable-speed compressors amongst themselves, but made it hard to compare variable-speed compressors to fixed-speed compressors. (NEEA, Public Meeting Transcript, No. 0016 at p. 60-62) Conversely, Sullivan-Palatek commented that fixed-speed and variable-speed compressors are different products with different applications, which shouldn't be compared with each other. (Sullivan-Palatek, Public Meeting Transcript, No. 0016 at pp. 61-62)

Kaeser Compressors commented that the efficiency and utility of a variable-speed compressor relative to a fixed-speed compressor is promoted by utilities to consumers and stressed that the primary goal of the metric should be consistent assessment of variable-speed compressor efficiency. (Kaeser Compressors, Public Meeting Transcript, No. 0016 at pp. 71-72) Sullair echoed this sentiment, stating that the industrial customers that purchase the equipment understand the energy efficiency associated with variable-speed compressors and purchase variable-speed compressors based on the best overall fit for the application. (Sullair, Public Meeting Transcript, No. 0016 at p. 72)

Sullair agreed that although measurements and efficiency standards for part-load operation of fixed-speed compressors may be useful, no standard has been established, tested or proven to measure compressor performance across all fixed-speed control methods (modulation, load-unload, variable displacement, etc.) employed by various manufacturers. As a result, Sullair commented that it did not support a part-load test procedure for fixed-speed compressors at this time. Sullair noted that preliminary work is being done by CAGI to measure one of these control methods (variable displacement) and supported further development of a test procedure or metric across multiple manufacturers and control types prior to adoption by DOE. (Docket No. EERE-2013-BT-STD-0040, Sullair, No. 0056 at pp. 16-17)

In agreement with the CA IOUs, ASAP, NEEA, and Sullair, DOE acknowledges that a part-load package isentropic efficiency metric for fixed-speed variable airflow compressors could acceptably represent the typical energy use of these compressors. DOE reviewed the scope and applicability of relevant, comparable testing and rating programs, namely, the CAGI Performance Verification Program and the EU Lot 31 draft standard for compressors. The CAGI Performance Verification Program separates rotary compressors into only two groupings: (1) “rotary compressors,” and (2) “rotary variable frequency drive compressors.”

The former rates compressors at only full-load operating pressure, while the latter allows for multiple ratings at reduced flows. However, as indicated by the name of the latter grouping, it encompasses only compressors driven by variable-frequency drives. Consequently, fixed-speed variable airflow compressors are considered “rotary compressors” by the CAGI Performance Verification Program, and rated at only full-load operating pressure.

For more information see:

http://www.cagi.org/performance-verification/data-sheets.aspx.

In addition, the EU Lot 31 draft standard defines a “fixed-speed rotary standard air compressor” to mean a rotary standard air compressor that is not equipped with a variable-speed drive when placed on the market; and defines a “variable-speed rotary standard air compressor” to mean a rotary standard air compressor that is equipped with a variable-speed drive when placed on the market. Consequently, similar to the CAGI program, the EU Lot 31 draft standard considers a fixed-speed variable airflow compressor to be a fixed-speed rotary standard air compressor, which is rated at only full-load operating pressure.

As a result of the research into relevant, comparable testing and rating programs for compressors, DOE agrees with Sullair that test methods for variable airflow fixed-speed compressors are still in the development stage and the limited available data is not yet fully verified. In other words, test methods are still a work in progress for this variety of fixed-speed compressors. Additionally, with no historical part-load performance data available for variable-flow fixed-speed compressors, DOE would be unable to establish baseline and maximum technologically feasible efficiency levels, and would be unable to complete any of the analyses required to assess and establish energy conservation standards. Alternatively, historical full-load isentropic efficiency currently exists for this equipment and was considered in the energy conservation standards NOPR.

In light of the precedent established by CAGI and the EU, the lack of a verified test method, and the lack of verified historical performance data, DOE concludes that it is not appropriate to establish part-load package isentropic efficiency as the rating metric for non-speed-varying varieties of variable airflow compressors at this time. Consequently, in this final rule, DOE reaffirms and establishes its NOPR test procedure that when rating a compressor for compliance purposes, full-load package isentropic efficiency applies to fixed-speed compressors, and part-load package isentropic efficiency applies to variable-speed compressors.

Although part-load package isentropic efficiency is not currently suitable as a regulatory metric for fixed-speed variable flow compressors, part-load performance information for these varieties of compressors can provide valuable information for the end user. Consequently, in this final rule DOE clarifies that manufacturers of fixed- and variable-speed compressors may continue making graphical or numerical representations of package isentropic efficiency and package specific power as functions of flow rate or rotational speed. In the test procedure NOPR, DOE proposed a similar allowance, applicable only to variable-speed compressors. 81 FR 27220, 27244 (May 5, 2016). DOE is opening this allowance to fixed-speed compressors to account for non-speed-varying varieties of variable airflow compressors and fixed-speed compressors that can vary speed continuously to adjust output flow, but cannot reach 40 percent of full-load actual volume flow rate.

DOE notes that graphical or numerical representations of package isentropic efficiency or package specific power at 40, 70, and 100 percent of the full-load actual volume flow rate must represent values measured in accordance with the DOE test procedure. DOE also notes that graphical or numerical representations of these metrics at any other load points must be generated using methods consistent with the DOE test procedure.

d. Metric Weights

In the test procedure NOPR, DOE proposed a part-load package isentropic efficiency metric that was a weighted composite of performance at multiple load points, following the structure of the EU Lot 31 draft standard. 81 FR 27220, 27233 (May 5, 2016). DOE further proposed weighting factors of 25, 50, and 25 percent for load points of 40, 70, and 100 percent of maximum flow, respectively. DOE cited alignment with the EU Lot 31 draft standard and a lack of industry weighting factors or real-world load profile data as rationale for the proposed weights. 81 FR 27220, 27234-5 (May 5, 2016).

In response to the proposed weights, P.R. China commented that there was no selection criteria provided to justify the weighting coefficients for the 40

percent, 70 percent, and 100 percent package isentropic efficiency values. (P.R. China, No. 0049 at p. 3) CAGI did not provide any direct comments, but CAGI commented that it was in agreement with DOE's proposal for items on which it did not directly comment. (CAGI, No. 0010, p. 3) Ingersoll Rand, Sullair, and Sullivan-Palatek supported CAGI's comments. (Ingersoll Rand, No. 0011 at p. 1; Sullair, No. 0006 at p. 1; Sullivan-Palatek, No. 0007 at p. 1)

In response to comments made by P.R. China regarding the justification of selected load weights, the part-load package isentropic efficiency metric is a benchmark for all variable-speed compressors. The benchmark's intent is not to mirror energy consumption for all consumers (which is calculated in the energy conversation standard), but to provide a consistent and repeatable measure of efficiency for variable-speed compressors. In this case, half of the weighting represents operating extremes (40 percent and 100 percent) for variable-speed compressors, and half characterizes the midpoint of those values (

i.e.,

70 percent). Furthermore, DOE did not receive any data providing real-world representative load profile data. However, even in the presence of such data any given weighting would only reflect energy consumption for units that happened to be operated at that particular load profile. Additionally, the selected weights are in alignment with the EU Lot 31 draft standard, which carries the benefits of familiarity for consumers and reduced compliance burden for manufacturers who do business in both the US and EU markets. For these reasons, as well as those discussed in the test procedure NOPR, DOE is adopting the metric weights, as proposed.

2. Package Specific Power

In the May 5, 2016 test procedure NOPR, DOE defined “package specific power” to mean the compressor power input at a given load point, divided by the actual volume flow rate at the same load point, as determined in accordance with the test procedures proposed for 10 CFR 431.344. 81 FR 27220, 27256 (May 5, 2016). DOE noted that package specific power provides users with a direct way to calculate the power required to deliver a particular flow rate of air. The CAGI Performance Verification Program currently uses this metric to characterize compressor performance.

Giv

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