Energy Conservation Program: Energy Conservation Standards for Compressors

Federal RegisterMay 19, 2016

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 430

[Docket Number EERE-2013-BT-STD-0040]

RIN 1904-AC83

Energy Conservation Program: Energy Conservation Standards for Compressors

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NOPR) and announcement of public meeting.

SUMMARY:

The Energy Policy and Conservation Act of 1975 (EPCA), as amended, prescribes energy conservation standards for various consumer products and certain commercial and industrial equipment. EPCA also authorizes DOE to establish standards for certain other types of industrial equipment, including compressors. Such standards must be technologically feasible and economically justified, and must save a significant amount of energy. In this document, DOE proposes energy conservation standards for compressors and announces a public meeting to receive comment on the proposed standards and associated analyses and results.

DATES:

Meeting:

DOE will hold a public meeting on Monday, June 20, 2016 from 1:00 p.m. to 5:00 p.m. in Washington, DC. The test procedure portion will be held in the morning. The meeting will also be broadcast as a webinar. See section VIII, “Public Participation,” for webinar registration information, participant instructions, and information about the capabilities available to webinar participants.

Comments:

DOE will accept comments, data, and information regarding this notice of proposed rulemaking (NOPR) before and after the public meeting, but no later than July 18, 2016. See section VIII, “Public Participation,” for details.

Comments regarding the likely competitive impact of the proposed standard should be sent to the Department of Justice contact listed in the

ADDRESSES

section before June 20, 2016.

ADDRESSES:

The public meeting will be held at the U.S. Department of Energy, Forrestal Building, Room 8E-089, 1000 Independence Avenue SW., Washington, DC 20585.

Instructions:

Any comments submitted must identify the NOPR on Energy Conservation Standards for compressors, and provide docket number EERE-2013-BT-STD-0040 and/or regulatory information number (RIN) 1904-AC83. Comments may be submitted using any of the following methods:

Federal eRulemaking Portal: www.regulations.gov

. Follow the instructions for submitting comments.

Email: AirCompressors2013STD0040@ee.doe.gov

. Include the docket number and/or RIN in the subject line of the message. Submit electronic comments in WordPerfect, Microsoft Word, PDF, or ASCII file format, and avoid the use of special characters or any form of encryption.

Postal Mail:

Ms. Brenda Edwards, U.S. Department of Energy, Building Technologies Office, Mailstop EE-5B, 1000 Independence Avenue SW., Washington, DC, 20585-0121. If possible, please submit all items on a compact disc (CD), in which case it is not necessary to include printed copies.

Hand Delivery/Courier:

Ms. Brenda Edwards, U.S. Department of Energy, Building Technologies Office, 950 L'Enfant Plaza, SW., Suite 600, Washington, DC 20024. Telephone: (202) 586-2945. If possible, please submit all items on a CD, in which case it is not necessary to include printed copies.

No telefacsimilies (faxes) will be accepted. For detailed instructions on submitting comments and additional information on the rulemaking process, see section VIII of this document (“Public Participation”).

Written comments regarding the burden-hour estimates or other aspects of the collection-of-information requirements contained in this proposed rule may be submitted to Office of Energy Efficiency and Renewable Energy through the methods listed above and by email to

Chad_S_Whiteman@omb.eop.gov

EPCA requires the Attorney General to provide DOE with a written determination of whether the proposed standard is likely to lessen competition. The U.S. Department of Justice Antitrust Division invites input from market participants and other interested persons with views on the likely competitive impact of the proposed standard. Interested persons may contact the Division at

energy.standards@usdoj.gov

before June 20, 2016. Please indicate in the “Subject” line of your email the title and Docket Number of this rulemaking notice.

Docket:

The docket, which includes

Federal Register

notices, 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 may not be publicly available, such as those containing information that is exempt from public disclosure.

A link to the docket Web page can be found at:

https://www.regulations.gov/#!docketDetail;D=EERE-2013-BT-STD-0040

. This Web page contains a link to the docket for this document on the

www.regulations.gov

site. The

www.regulations.gov

Web page contains simple instructions on how to access all documents, including public comments, in the docket. See section VIII, “Public Participation,” for further information on how to submit comments through

www.regulations.gov

FOR FURTHER INFORMATION CONTACT:

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:

compressors@ee.doe.gov

Peter Cochran, U.S. Department of Energy, Office of the General Counsel, GC-71, 1000 Independence Avenue SW., Washington, DC, 20585-0121. Telephone: (202) 586-9496. Email:

Peter.Cochran@hq.doe.gov

For further information on how to submit a comment, review other public comments and the docket, or participate in the public meeting, contact Ms. Brenda Edwards at (202) 586-2945 or by email:

Brenda.Edwards@ee.doe.gov

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Synopsis of the Proposed Rule

A. Benefits and Costs to Consumers

B. Impact on Manufacturers

C. National Benefits and Costs

D. Conclusion

II. Introduction

A. Authority

B. Background

1. Current Standards

2. History of Standards Rulemaking for Compressors

III. General Discussion

A. Definition of Covered Equipment

B. Scope of the Energy Conservation Standards in This Rulemaking

1. Equipment System Boundary

2. Compressed Gas

3. Compression Principle

4. Driver Type

a. Combustion Engines

b. Motor Phase Count

c. Styles of Electric Motor

5. Equipment Capacity

6. Full-load Operating Pressure

C. Test Procedure

D. Technological Feasibility

1. General

2. Maximum Technologically Feasible Levels

E. Compliance Date

F. Energy Savings

1. Determination of Savings

2. Significance of Savings

G. Economic Justification

1. Specific Criteria

a. Economic Impact on Manufacturers and Consumers

b. Savings in Operating Costs Compared To Increase in Price (LCC and PBP)

c. Energy Savings

d. Lessening of Utility or Performance of Equipment

e. Impact of Any Lessening of Competition

f. Need for National Energy Conservation

g. Other Factors

2. Rebuttable Presumption

H. Compressor Industry Recommendation

1. Summary

2. Specific Provisions

IV. Methodology and Discussion of Related Comments

A. Market and Technology Assessment

1. Equipment Classes

a. Compression Principle

b. Lubricant Presence

c. Cooling Method

d. Motor Speed

e. Motor Phase Count

f. List of Proposed Equipment Classes

2. European Union Regulatory Action

a. Specific Suggested Requirements

b. Next Steps

3. Technology Options

a. Multi-Staging

b. Air-End Improvement

c. Auxiliary Component Improvement

B. Screening Analysis

1. Screened-Out Technologies

2. Remaining Technologies

C. Engineering Analysis

1. Summary of Significant Data Sources

a. CAGI Data Sheets

b. Lot 31—European Union Ecodesign Preparatory Study on Compressors

c. Confidential Manufacturer Equipment Data

d. Online Retailer Price Data

2. Harmonization With Lot 31

3. Representative Equipment

4. Design Options and Available Energy Efficiency Improvements

5. Efficiency Levels

a. Direct From Lot 31

b. Developed From CAGI Database

c. Scaled From Other Equipment Classes, Using U.S. Data

6. Manufacturer Selling Price

a. Direct Scaling From Lot 31

b. Scaling With U.S. MSP Data

c. MSPs for Water-Cooled Equipment

d. New Relationships From U.S. Data

7. Manufacturer Production Cost

8. Other Analytical Outputs

D. Markups Analysis

E. Energy Use Analysis

1. Applications

2. Annual Hours of Operation

3. Load Profiles

4. Capacity Control Strategies

5. Compressor Sizing

F. Life-Cycle Cost and Payback Period Analysis

1. Equipment Cost

2. Installation Cost

3. Annual Energy Consumption

4. Energy Prices

5. Repair and Maintenance Costs

6. Equipment Lifetime

7. Discount Rates

8. Efficiency Distribution in the No-New-Standards Case

9. Payback Period Analysis

G. Shipments Analysis

H. National Impact Analysis

1. Equipment Efficiency Trends

2. National Energy Savings

3. Net Present Value Analysis

I. Consumer Subgroup Analysis

J. Manufacturer Impact Analysis

1. Overview

2. GRIM Analysis

a. GRIM Key Inputs

b. GRIM Scenarios

3. Manufacturer Interviews

a. Conversion Requirements

b. Engineering Constraints and Development Cycle Times

c. Relationship to the Draft European Union Energy Efficiency Standards

d. Unfair Advantages for Replacement Technologies

e. Uncertainty of Compliance Cost for Reciprocating Equipment

K. Emissions Analysis

L. Monetizing Carbon Dioxide and Other Emissions Impacts

1. Social Cost of Carbon

a. Monetizing Carbon Dioxide Emissions

b. Development of Social Cost of Carbon Values

c. Current Approach and Key Assumptions

2. Social Cost of Other Air Pollutants

M. Utility Impact Analysis

N. Employment Impact Analysis

V. Analytical Results and Conclusions

A. Trial Standard Levels

B. Economic Justification and Energy Savings

1. Economic Impacts on Individual Consumers

a. Life-Cycle Cost and Payback Period

b. Consumer Subgroup Analysis

c. Rebuttable Presumption Payback

2. Economic Impacts on Manufacturers

a. Industry Cash Flow Analysis Results

b. Impacts on Employment

c. Impacts on Manufacturing Capacity

d. Impacts on Subgroups of Manufacturers

e. Cumulative Regulatory Burden

3. National Impact Analysis

a. Significance of Energy Savings

b. Net Present Value of Consumer Costs and Benefits

c. Indirect Impacts on Employment

4. Impact on Utility or Performance of Equipment

5. Impact of Any Lessening of Competition

6. Need of the Nation To Conserve Energy

7. Other Factors

8. Summary of National Economic Impacts

C. Conclusion

1. Benefits and Burdens of TSLs Considered for Compressor Standards

2. Summary of Annualized Benefits and Costs of the Proposed Standards

VI. Certification Requirements

VII. Procedural Issues and Regulatory Review

A. Review Under Executive Orders 12866 and 13563

B. Review Under the Regulatory Flexibility Act

1. Description on Estimated Number of Small Entities Regulated

a. Methodology for Estimating the Number of Small Entities

b. Compressor Industry Structure and Nature of Competition

c. Manufacturer Participation

2. Description and Estimate of Compliance Requirements

3. Duplication, Overlap, and Conflict With Other Rules and Regulations

4. Significant Alternatives to the Rule

C. Review Under the Paperwork Reduction Act

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 the Treasury and General Government Appropriations Act, 2001

K. Review Under Executive Order 13211

L. Review Under the Information Quality Bulletin for Peer Review

VIII. Public Participation

A. Attendance at the Public Meeting

B. Procedure for Submitting Prepared General Statements for Distribution

C. Conduct of the Public Meeting

D. Submission of Comments

E. Issues on Which DOE Seeks Comment

IX. Approval of the Office of the Secretary

I. Synopsis of the Proposed Rule

Title III of the Energy Policy and Conservation Act of 1975, as amended (“EPCA” or, in context, “the Act”), sets forth a variety of provisions designed to improve energy efficiency. (42 U.S.C. 6291,

et seq.

) Part C of Title III, which for editorial reasons was re-designated 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.” EPCA provides that DOE may include a type of industrial equipment as covered equipment if it determines that to do so is necessary to carry out the purposes of Part A-1. (42 U.S.C. 6312(b)). DOE has proposed such a determination for compressors, the subject of this document (see section II.A for further discussion).

EPCA authorizes DOE to prescribe energy conservation standards for those types of industrial equipment which the Secretary classifies as covered equipment. (42 U.S.C. 6311(2) and 6312). Pursuant to EPCA, any new or amended energy conservation standard must be designed to achieve the maximum improvement in energy

efficiency that is technologically feasible and economically justified. (42 U.S.C. 6295(o)(2)(A) and 6316(a)). Furthermore, the new or amended standard must result in a significant conservation of energy. (42 U.S.C. 6295(o)(3)(B) and 6316(a)).

In accordance with the relevant EPCA provisions, DOE proposes new energy conservation standards for compressors. The proposed standards, which are expressed in terms of package isentropic efficiency (

i.e.,

a parameter used to measure the degree of degradation of energy in steady-flow devices), or the ratio of the theoretical isentropic power required for a compression process to the actual power required for the same process, are shown in Table I.1. Table I.2 through Table I.5 provide mathematical coefficients required to calculate package isentropic efficiency in Table I.1. For “Fixed-speed compressor” equipment classes, the relevant Package Isentropic Efficiency is Full-Load Package Isentropic Efficiency; for “Variable-speed compressor” equipment classes, the relevant Package Isentropic Efficiency is Part-Load Package Isentropic Efficiency. Both Full- and Part-Load Package Isentropic Efficiency are determined in accordance with the test methods proposed in the April 2016 Compressors Test Procedure Notice of Proposed Rulemaking (“test procedure NOPR”) 81 FR 27220.

These proposed standards, if adopted, would apply to all compressors listed in Table I.1 and manufactured in, or imported into, the United States starting five years after the publication of the final rule for this rulemaking.

See

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

denotes the full-load actual volume flow rate

of the compressor, in actual cubic feet per minute (“acfm”).

Standard levels are expressed as a function of full-load actual volume flow rate for each equipment class, and may be calculated by inserting values from rightmost two columns into the second leftmost column. Doing so will yield an efficiency-denominated function of actual volume flow rate in acfm.

The test procedure NOPR defines a term “actual volume flow rate” to characterize compressor output flow as “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.” It also proposes a procedure for identifying a compressor's full-load actual volume flow rate.

Actual cubic feet per minute (“acfm”) is an industry convention that describes the actual volume of air emerging from a compressor, but expressed as though the air were allowed to expand to ambient conditions at the compressor inlet.

Table I.1—Proposed Energy Conservation Standards for Compressors

Equipment class

Minimum package isentropic

efficiency

Regr

(package isentropic

efficiency

reference curve)

(percentage loss reduction)

Rotary; Lubricated; Air-cooled; Fixed-speed

Regr

+ (1− η

Regr

) * (d/100)

−0.00928 * ln(.472 * V

)

+ 0.139 * ln(.472 * V

) + 0.271

−15

Rotary; Lubricated; Air-cooled; Variable-speed

Regr

+ (1− η

Regr

) * (d/100)

−0.0155 * ln(.472 * V

)

+ 0.216 * ln(.472 * V

) + 0.00905

−10

Rotary; Lubricated; Water-cooled; Fixed-speed

.0235 + η

Regr

+ (1− η

Regr

) * (d/100)

−0.00928 * ln(.472 * V

)

+ 0.139 * ln(.472 * V

) + 0.271

−15

Rotary; Lubricated; Water-cooled; Variable-speed

.0235 + η

Regr

+ (1− η

Regr

) * (d/100)

−0.0155 * ln(.472 * V

)

+ 0.216 * ln(.472 * V

) + 0.00905

−15

Rotary; Lubricant-free; Air-cooled; Fixed-speed

Regr

+ (1− η

Regr

) * (d/100)

* ln(.472 * V

)

+ B

* ln(.472 * V

) + C

−11

Rotary; Lubricant-free; Air-cooled; Variable-speed

Regr

+ (1− η

Regr

) * (d/100)

* ln(.472 * V

)

+ B

* ln(.472 * V

) + C

−13

Rotary; Lubricant-free; Water-cooled; Fixed-speed

* ln(.472 * V

)

+ B

* ln(.472 * V

) + C

+ η

Regr

+ (1− η

Regr

) * (d/100)

* ln(.472 * V

)

+ B

* ln(.472 * V

) + C

−11

Rotary; Lubricant-free; Water-cooled; Variable-speed

* ln(.472 * V

)

+ B

* ln(.472 * V

) + C

+ η

Regr

+ (1− η

Regr

) * (d/100)

* ln(.472 * V

)

+ B

* ln(.472 * V

) + C

−13

Table I.2—Coefficients for Proposed Energy Conservation Standards for Rotary, Lubricant-free, Air- and Water-Cooled, Fixed-Speed Compressors

Full-load actual volume flow rate range (actual cubic feet per minute (acfm))

0 ≤ V

≤ 161

−0.00928

0.139

0.191

161 ≤ V

≤ 2125

0.00281

0.0344

0.417

2125 ≤ V

−0.00928

0.139

0.271

Table I.3—Coefficients for Proposed Energy Conservation Standards for Rotary, Lubricant-Free, Air- and Water-Cooled, Variable-Speed Compressors

Full-Load Actual Volume Flow Rate Range (acfm)

0 ≤ V

≤ 102

−0.0155

0.216

−0.0984

102 ≤ V

≤ 1426

0.000

0.0958

0.134

1426 ≤ V

−0.0155

0.216

0.00905

Table I.4—Coefficients for Proposed Energy Conservation Standards for Rotary, Lubricant-Free, Water-Cooled, Fixed-Speed Compressors

Full-Load Actual Volume Flow Rate Range (acfm)

0 ≤ V

< 102

102 ≤ V

−0.00924

0.117

−0.315

Table I.5—Coefficients for Proposed Energy Conservation Standards for Rotary, Lubricant-Free, Water-Cooled, Variable-Speed Compressors

Full-Load Actual Volume Flow Rate Range (acfm)

0 ≤ V

< 74

74 ≤ V

0.000173

0.00783

−0.0300

DOE has tentatively concluded that the proposed standards represent the maximum improvement in energy efficiency that is technologically feasible and economically justified, and would result in the significant conservation of energy. DOE further notes that air compressors achieving these standard levels are already commercially available for all proposed equipment classes. Based on the analyses described in this preamble, DOE has tentatively concluded that the benefits of the proposed standards to the nation (energy savings, positive NPV of consumer benefits, consumer LCC savings, and emission reductions) would outweigh the burdens (large loss of INPV for manufacturers and LCC increases for some consumers).

DOE is also seriously considering the adoption of a more-stringent energy efficiency standard in this rulemaking. Based on consideration of the public comments DOE receives in response to this notice and related information collected and analyzed during the course of this rulemaking effort, DOE may adopt energy efficiency levels presented in this notice that is higher than the proposed standards, or some combination of level(s) that incorporate the proposed standards in part. As discussed in more detail in section V.C.1, DOE is strongly considering a TSL 3 standard for a compressor standard as an option with greater than two times the annual net benefits of DOE's current proposed TSL 2.

The proposed standards correspond to trial standard level (TSL) 2. As discussed in section V.C, DOE has tentatively concluded that TSL 3, which is comprised of more stringent energy efficiency standards than TSL 2, is not economically justified. However, because TSL 3 has significant benefits, including much higher national energy savings, national NPV, and emissions reductions than those resulting from TSL 2 (see Table V.36), DOE is still considering the merits of standards at TSL 3. Accordingly, DOE invites comments on whether DOE should adopt standards for compressors at TSL 3 instead of at TSL 2. This is identified as Issue 1 in section VIII.E, “Issues on Which DOE Seeks Comment.”

A. Benefits and Costs to Consumers

Table I.6 presents DOE's evaluation of the economic impacts of the proposed standards on end users of compressors, as measured by the average life-cycle cost (LCC) savings and the simple payback period (PBP).

The average LCC savings are positive for all equipment classes for which a standard has been proposed, and the PBP is less than the average lifetime of compressors, which is estimated to be between 9 to 13 years (see section IV.F.6).

The average LCC savings are measured relative to the no-new standards case efficiency distribution in the no-new-standards case, which depicts the market in the compliance year in the absence of standards (see section IV.F.9). The simple PBP, which is designed to compare specific efficiency levels, is measured relative to the baseline model (see section IV.C.1.a).

Table I.6—Impacts of Proposed Energy Conservation Standards on End Users of Compressors

Equipment Class

Average LCC Savings (

2015$

)

Simple

Payback

Period (

years

)

Rotary, Fixed Speed, Lubricated, Air Cooled

(RP_FS_L_AC )

$8,902

1.7

Rotary, Fixed Speed, Lubricated, Water Cooled

(RP_FS_L_WC )

15,011

2.4

Rotary, Fixed Speed, Lubricant-Free Air Cooled

(RP_FS_LF_AC) *

n.a.

Rotary, Fixed Speed, Lubricant-Free Water Cooled (RP_FS_LF_WC) *

n.a.

Rotary, Variable Speed, Lubricated, Air Cooled

(RP_VS_L_AC )

6,061

2.5

Rotary, Variable Speed, Lubricated, Water Cooled

(RP_VS_L_WC )

13,865

3.4

Rotary, Variable Speed, Lubricant-Free Air Cooled (RP_VS_LF_AC) *

n.a.

Rotary, Variable Speed, Lubricant-Free Water Cooled (RP_VS_LF_WC) *

n.a.

Reciprocating, Single-Phase, Lubricated

(R1_FS_L_XX) **

n.a.

Reciprocating, Three-Phase, Lubricated

(R3_FS_L_XX) **

n.a.

* No increase in efficiency is proposed for this equipment class.

** No new standard is proposed for this equipment class.

DOE's analysis of the impacts of the proposed standards on end users is described in section V.B.1 of this document.

B. Impact on Manufacturers

The industry net present value (INPV) is the sum of the discounted cash flows to the industry from the base year through the end of the analysis period (2015 to 2051). Using a real discount rate of 8.7 percent, DOE estimates that the INPV for manufacturers of compressors in the case without standards is $497.1 million in 2014$. Under the proposed standards, DOE expects that manufacturers may lose up to 11.6 percent of this INPV, or approximately $57.8 million.

DOE's analysis of the impacts of the proposed standards on manufacturers is described in section IV.J of this document.

C. National Benefits and Costs

All monetary values in this document are expressed in 2015 dollars and, where appropriate, are discounted to 2015 unless explicitly stated otherwise. Energy savings in this section refer to the full-fuel-cycle savings (see section IV.H for discussion).

DOE's analyses indicate that the proposed energy conservation standards for compressors would save a significant amount of energy. Relative to the case without new standards, the lifetime energy savings for compressors purchased in the 30-year period that begins in the anticipated first full year of compliance with the new standards (2022-2051)

amount to 0.18 quadrillion British thermal units (Btu), or quads.

This represents a savings of 0.4 percent relative to the energy use of these equipment in the case without new standards (referred to as the “no-new-standards case”).

The analysis uses January 1st, 2022 to represent the expected compliance date in late 2021. Therefore, the 30-year analysis period is referred to as 2022-2051.

The quantity refers to full-fuel-cycle (FFC) energy savings. FFC energy savings includes the energy consumed in extracting, processing, and transporting primary fuels (

i.e.,

coal, natural gas, petroleum fuels), and, thus, presents a more complete picture of the impacts of energy efficiency standards. For more information on the FFC metric, see section IV.H.1.

The cumulative net present value (NPV) of total consumer costs and savings of the proposed standards for compressors ranges from $0.21 billion (at a 7-percent discount rate) to $0.62 billion (at a 3-percent discount rate). This NPV expresses the estimated total value of future operating-cost savings minus the estimated increased equipment costs for compressors purchased in 2022-2051.

In addition, the proposed standards for compressors would have significant environmental benefits. DOE estimates that the proposed standards would result in cumulative emission reductions (over the same period as for energy savings) of 10.6 million metric tons (Mt)

of carbon dioxide (CO

), 5.8 thousand tons of sulfur dioxide (SO

), 19.5 thousand tons of nitrogen oxides (NO

), 46.7 thousand tons of methane (CH

), 0.1 thousand tons of nitrous oxide (N

O), and 0.02 tons of mercury (Hg).

The cumulative reduction in CO

emissions through 2030 amounts to 1.2 Mt, which is equivalent to the emissions resulting from the annual electricity use of 0.11 million homes.

A metric ton is equivalent to 1.1 short tons. Results for emissions other than CO

are presented in short tons.

DOE calculated emissions reductions relative to the no-new-standards case, which reflects key assumptions in the

Annual Energy Outlook 2015

(

AEO 2015

) Reference case.

AEO 2015

generally represents current legislation and environmental regulations for which implementing regulations were available as of October 31, 2014.

The value of the CO

reductions is calculated using a range of values per metric ton of CO

(otherwise known as the Social Cost of Carbon, or SCC) developed by a recent Federal interagency process.

The derivation of the SCC values is discussed in section IV.L. Using discount rates appropriate for each set of SCC values (see Table I.X), DOE estimates the present monetary value of the CO

emissions reduction (not including CO

equivalent emissions of other gases with global warming potential) is between $0.06 billion and $0.99 billion, with a value of $0.32 billion using the central SCC case represented by $40.0/t in 2015. DOE also estimates the present monetary value of the NO

emissions reduction to be $0.01 billion at a 7-percent discount rate and $0.03 billion at a 3-percent discount rate.

DOE is investigating appropriate valuation of the reduction in methane and other emissions, and did not include any values in this rulemaking.

United States Government—Interagency Working Group on Social Cost of Carbon.

Technical Support Document: Technical Update of the Social Cost of Carbon for Regulatory Impact Analysis Under Executive Order 12866.

May 2013. Revised July 2015.

https://www.whitehouse.gov/sites/default/files/omb/inforeg/scc-tsd-final-july-2015.pdf

DOE estimated the monetized value of NO

emissions reductions associated with electricity savings using benefit per ton estimates from the Regulatory Impact Analysis for the Clean Power Plan Final Rule, published in August 2015 by EPA's Office of Air Quality Planning and Standards. Available at

http://www.epa.gov/cleanpowerplan/clean-power-plan-final-rule-regulatory-impact-analysis

. See section IV.L.2 for further discussion. The U.S. Supreme Court has stayed the rule implementing the Clean Power Plan until the current litigation against it concludes.

Chamber of Commerce, et al.

EPA, et al.,

Order in Pending Case, 136 S.Ct. 999 (Mem). However, the benefit-per-ton estimates established in the Regulatory Impact Analysis for the Clean Power Plan are based on scientific studies that remain valid irrespective of the legal status of the Clean Power Plan. Note that DOE is primarily using a national benefit-per-ton estimate for NO

emitted from the Electricity Generating Unit sector based on an estimate of premature mortality derived from the ACS study (Krewski et al. 2009). If the benefit-per-ton estimates were based on the Six Cities study (Lepuele et al. 2011), the values would be nearly two-and-a-half times larger.

Table I.7 summarizes the economic benefits and costs expected to result from the proposed standards for compressors.

Table I.7.—Summary of Economic Benefits and Costs of Proposed Energy Conservation Standards for Compressors

[TSL 2] *

Category

Present value

(billion 2015$)

Discount rate

(percent)

Benefits:

Consumer Operating Cost Savings

0.3

0.8

Reduction (using mean SCC at 5% discount rate)

0.1

Reduction (using mean SCC at 3% discount rate)

0.3

Reduction (using mean SCC at 2.5% discount rate)

0.5

2.5

Reduction (using 95th percentile SCC at 3% discount rate)

1.0

Reduction †

0.0

Total Benefits ‡

0.7

1.2

Costs:

Consumer Incremental Installed Costs

0.1

0.2

Total Net Benefits:

Including CO

and NO

Reduction Monetized Value ‡

0.6

1.0

This table presents the costs and benefits associated with compressors shipped in 2022−2051. These results include benefits to consumers which accrue after 2048 from the equipment purchased in 2022−2051. The costs account for the incremental variable and fixed costs incurred by manufacturers due to the standard, some of which may be incurred in preparation for the rule.

The interagency group selected four sets of SCC values for use in regulatory analyses. Three sets of values are based on the average SCC from the integrated assessment models, at discount rates of 5%, 3%, and 2.5%. For example, for 2015 emissions, these values are $12.4/t, $40.6/t, and $63.2/t, in 2015$, respectively. The fourth set ($118/t in 2015$ for 2015 emissions), which represents the 95th percentile of the SCC distribution calculated using a 3% discount rate, is included to represent higher-than-expected impacts from temperature change further out in the tails of the SCC distribution. The SCC values are emission year specific. See section IV.L.1 for more details.

† DOE estimated the monetized value of NO

emissions reductions using benefit per ton estimates from the

Regulatory Impact Analysis for the Clean Power Plan Final Rule,

published in August 2015 by EPA's Office of Air Quality Planning and Standards. (Available at:

http://www.epa.gov/cleanpowerplan/clean-power-plan-final-rule-regulatory-impact-analysis

See section IV.L.2 for further discussion. Note that DOE is primarily using a national benefit-per-ton estimate for NO

emitted from the Electricity Generating Unit sector based on an estimate of premature mortality derived from the ACS study (Krewski et al., 2009). If the benefit-per-ton estimates were based on the Six Cities study (Lepuele et al., 2011), the values would be nearly two-and-a-half times larger.

‡ Total Benefits for both the 3% and 7% cases are presented using only the average SCC with 3-percent discount rate.

The benefits and costs of the proposed standards, for compressors sold in 2022-2051, can also be expressed in terms of annualized values. The monetary values for the total annualized net benefits are the sum of: (1) The national economic value of the benefits in reduced consumer operating costs, minus (2) the increase in equipment purchase prices and installation costs, plus (3) the value of the benefits of CO

and NO

emission reductions, all annualized.

To convert the time-series of costs and benefits into annualized values, DOE calculated a present value in 2016, the year used for discounting the NPV of total consumer costs and savings. For the benefits, DOE calculated a present value associated with each year's shipments in the year in which the shipments occur (

e.g.,

2020 or 2030), and then discounted the present value from each year to 2016. The calculation uses discount rates of 3 and 7 percent for all costs and benefits except for the value of CO

reductions, for which DOE used case-specific discount rates, as shown in Table I.3. Using the present value, DOE then calculated the fixed annual payment over a 30-year period, starting in the compliance year that yields the same present value.

The national operating savings are domestic U.S. consumer monetary savings that occur as a result of purchasing the covered products. The national operating cost savings is measured for the lifetime of compressors shipped in 2022-2051. The CO

reduction is a benefit that accrues globally due to decreased domestic energy consumption that is expected to result from this rule. Because CO

emissions have a very long residence time in the atmosphere, the SCC values in future years reflect future CO

-emissions impacts that continue beyond 2100 through 2300.

Estimates of annualized benefits and costs of the proposed standards are shown in Table I.8. The results under the primary estimate are as follows.

Using a 7-percent discount rate for benefits and costs other than CO

reduction (for which DOE used a 3-percent discount rate along with the average SCC series that has a value of $40.0/t in 2015), the estimated cost of the standards proposed in this rule is 10.4 million per year in increased equipment costs, while the estimated annual benefits are $36.0 million in reduced equipment operating costs, $19.2 million in CO

reductions, and $1.4 million in reduced NO

emissions. In this case, the net benefit amounts to $46 million per year.

Using a 3-percent discount rate for all benefits and costs and the average SCC series that has a value of $40.0/t in 2015, the estimated cost of the proposed standards is $10.9 million per year in increased equipment costs, while the estimated annual benefits are $48.4 million in reduced operating costs, $19.2 million in CO

reductions, and $2.0 million in reduced NO

emissions. In this case, the net benefit amounts to $59 million per year.

Table I.8—Annualized Benefits and Costs of Proposed Energy Conservation Standards for Compressors

[TSL 2]

Discount rate

Million 2015$/year

Primary estimate *

Low net benefits

estimate *

High net benefits

estimate *

Benefits

Consumer Operating Cost Savings

36.0

29.3

43.7

48.4

38.9

60.4

Reduction (using mean SCC at 5% discount rate)

5.7

4.8

6.9

Reduction (using mean SCC at 3% discount rate)

19.2

16.0

23.2

Reduction (using mean SCC at 2.5% discount rate)

2.5%

28.1

23.3

33.9

Reduction (using 95th percentile SCC at 3% discount rate )

58.5

48.6

70.6

Reduction †

1.4

1.2

3.7

2.0

1.6

5.4

Total Benefit ††

7% plus CO

range

43 to 96

35 to 79

54 to 118

3% plus CO

range

56 to 109

45 to 89

73 to 136

Costs

Consumer Incremental Installed Equipment Costs

10.4

10.9

8.9

9.2

11.8

12.4

Net Benefits

Total ††

7% plus CO

range

33 to 85

26 to 70

42 to 106

3% plus CO

range

45 to 98

36 to 80

60 to 124

* This table presents the annualized costs and benefits associated with compressors shipped in 2022−2051. These results include benefits to consumers which accrue after 2051 from the equipment purchased in 2022-2051. The Primary, Low Benefits, and High Benefits Estimates utilize projections of energy prices from the

AEO 2015

Reference case, Low Economic Growth case, and High Economic Growth case, respectively. In addition, incremental product costs reflect a constant trend in the Primary Estimate, an increasing trend in the Low Benefits Estimate, and a decreasing trend in the High Benefits Estimate. The methods used to derive projected price trends are explained in section IV.H.1.]. Note that the Benefits and Costs may not sum to the Net Benefits due to rounding.

** The CO

reduction benefits are calculated using 4 different sets of SCC values. The first three use the average SCC calculated using 5%, 3%, and 2.5% discount rates, respectively. The fourth represents the 95th percentile of the SCC distribution calculated using a 3% discount rate. The SCC values are emission year specific. See section IV.L.1 for more details.

† DOE estimated the monetized value of NO

emissions reductions using benefit per ton estimates from the

Regulatory Impact Analysis for the Clean Power Plan Final Rule,

published in August 2015 by EPA's Office of Air Quality Planning and Standards. (Available at:

http://www.epa.gov/cleanpowerplan/clean-power-plan-final-rule-regulatory-impact-analysis

See section IV.L.2 for further discussion. For DOE's Primary Estimate and Low Net Benefits Estimate, the agency is using a national benefit-per-ton estimate for NO

emitted from the Electric Generating Unit sector based on an estimate of premature mortality derived from the ACS study (Krewski et al., 2009). For DOE's High Net Benefits Estimate, the benefit-per-ton estimates were based on the Six Cities study (Lepuele et al., 2011), which are nearly two-and-a-half times larger than those from the ACS study.

†† Total Benefits for both the 3% and 7% cases are derived using the series corresponding to the average SCC with a 3-percent discount rate ($40.0/t case). In the rows labeled “7% plus CO

range” and “3% plus CO

range,” the operating cost and NO

benefits are calculated using the labeled discount rate, and those values are added to the full range of CO

values.

DOE's analysis of the national impacts of the proposed standards is described in sections IV.H, IV.K and IV.L of this document.

D. Conclusion

DOE is also seriously considering the adoption of a more -stringent energy efficiency standard in this rulemaking. Based on consideration of the public comments DOE receives in response to this notice and related information collected and analyzed during the course of this rulemaking effort, DOE may adopt energy efficiency levels presented in this notice that is higher than the proposed standards, or some combination of level(s) that incorporate the proposed standards in part. As discussed in more detail in section V.C.1, DOE is strongly considering a TSL 3 standard for a compressor standard as an option with greater than two times the annual net benefits of DOE's current proposed TSL 2.

II. Introduction

The following section briefly discusses the statutory authority underlying this proposed rule, as well as some of the relevant historical background related to the establishment of standards for compressors.

A. Authority

EPCA provides that 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(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)). DOE has proposed to determine that because (1) DOE may only prescribe energy conservation standards 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, including compressors as covered equipment is necessary to carry out the purposes of Part A-1. 77 FR 76972 (Dec. 31, 2012).

Pursuant to EPCA, any new or amended energy conservation standard for compressors must be designed to achieve the maximum improvement in energy efficiency that is technologically feasible and economically justified. (42 U.S.C. 6295(o)(2)(A) and 6316(a)). Furthermore, the new or amended standard must result in a significant conservation of energy. (42 U.S.C. 6295(o)(3)(B) and 6316(a)).

Pursuant to EPCA, DOE's energy conservation program for covered products consists essentially of four parts: (1) Testing; (2) labeling; (3) the establishment of Federal energy conservation standards; and (4) certification and enforcement procedures. For commercial and industrial products, DOE is primarily responsible for labeling requirements. Subject to certain criteria and conditions, DOE is required to develop test procedures to measure the energy efficiency, energy use, or estimated annual operating cost of each covered product. (42 U.S.C. 6295(o)(3)(A) and 6314) Manufacturers of covered products must use the prescribed DOE test procedure as the basis for certifying to DOE that their products comply with the applicable energy conservation standards adopted under EPCA and when making representations to the public regarding the energy use or efficiency of those products. (42 U.S.C. 6293(c), 6295(s) and 6316(a)) Similarly, DOE must use these test procedures to determine whether the products comply with standards adopted pursuant to EPCA. (42 U.S.C. 6295(s) and 6316(a)) There are currently no DOE test procedures for compressors. DOE issued a test procedure NOPR for Compressors in April 2016. Upon finalization, any DOE test procedure for compressors will appear at title 10 of the Code of Federal Regulations (CFR) part 431, subpart T, appendix A.

DOE follows specific statutory criteria for prescribing new or amended standards for covered equipment, including compressors. Any new or amended standard for a covered product must be designed to achieve the maximum improvement in energy efficiency that is technologically feasible and economically justified. (42 U.S.C. 6316(a), and 6295(o)(2)(A) and (3)(B)) Furthermore, DOE may not adopt any standard that would not result in the significant conservation of energy. (42 U.S.C. 6295(o)(3) and 6316(a)) Moreover, DOE may not prescribe a standard: (1) For certain products, including compressors, if no test procedure has been established for the product, or (2) if DOE determines by rule that the standard is not technologically feasible or economically justified. (42 U.S.C. 6295(o)(3)(A)-(B) and 6316(a)) In deciding whether a proposed standard is economically justified, DOE must determine whether the benefits of the standard exceed its burdens. (42 U.S.C. 6295(o)(2)(B)(i) and 6316(a)) DOE must make this determination after receiving comments on the proposed standard, and by considering, to the greatest extent practicable, the following seven statutory factors:

(1) The economic impact of the standard on manufacturers and consumers of the products subject to the standard;

(2) The savings in operating costs throughout the estimated average life of the covered products in the type (or class) compared to any increase in the price, initial charges, or maintenance expenses for the covered products that are likely to result from the standard;

(3) The total projected amount of energy (or as applicable, water) savings likely to result directly from the standard;

(4) Any lessening of the utility or the performance of the covered products likely to result from the standard;

(5) The impact of any lessening of competition, as determined in writing by the Attorney General, that is likely to result from the standard;

(6) The need for national energy and water conservation; and

(7) Other factors the Secretary of Energy considers relevant. (42 U.S.C. 6295(o)(2)(B)(i)(I)-(VII) and 6316(a))

Further, EPCA, as codified, establishes a rebuttable presumption that a standard is economically justified if the Secretary finds that the additional cost to the consumer of purchasing a product complying with an energy conservation standard level will be less than three times the value of the energy savings during the first year that the consumer will receive as a result of the standard, as calculated under the applicable test procedure. (42 U.S.C. 6295(o)(2)(B)(iii) and 6316(a))

EPCA, as codified, also contains what is known as an “anti-backsliding” provision, which prevents the Secretary from prescribing any amended standard that either increases the maximum allowable energy use or decreases the minimum required energy efficiency of a covered product. (42 U.S.C. 6295(o)(1) and 6316(a)) Also, the Secretary may not prescribe an amended or new standard if interested persons have established by a preponderance of the evidence that the standard is likely to result in the unavailability in the United States in any covered product type (or class) of performance characteristics (including reliability), features, sizes, capacities, and volumes that are substantially the same as those generally available in the United States. (42 U.S.C. 6295(o)(4) and 6316(a))

Additionally, 42 U.S.C. 6295(q)(1) and 6316(a) specifies requirements when promulgating an energy conservation standard for a covered product that has two or more subcategories. DOE must specify a different standard level for a type or class of product that has the same function or intended use, if DOE determines that products within such group: (A) Consume a different kind of energy from that consumed by other covered products within such type (or class); or (B) have a capacity or other performance-related feature which other products within such type (or class) do not have and such feature justifies a higher or lower standard. (42 U.S.C. 6295(q)(1) and 6316(a)) In determining whether a performance-related feature justifies a different standard for a group of products, DOE must consider such factors as the utility to the consumer of the feature and other factors DOE deems appropriate.

Id.

Any rule prescribing such a standard must include an explanation of the basis on which such higher or lower level was established. (42 U.S.C. 6295(q)(2) and 6316(a))

Federal energy conservation requirements generally supersede State

laws or regulations concerning energy conservation testing, labeling, and standards. (42 U.S.C. 6297(a)-(c) and 6316(a)) DOE may, however, grant waivers of Federal preemption for particular State laws or regulations, in accordance with the procedures and other provisions set forth under 42 U.S.C. 6297(d) and 6316(a)).

B. Background

1. Current Standards

DOE does not currently have a test procedure or energy conservation standard for compressors. In considering whether to establish standards for compressors, DOE issued a Proposed Determination of Coverage on December 31, 2012. 77 FR 76972.

2. History of Standards Rulemaking for Compressors

DOE initiated its rulemaking efforts to examine the possibility of setting energy conservation standards for compressors by publishing a notice that announced the availability of a framework document and a public meeting to discuss that document and invite comment from interested parties.

79 FR 06839. The Framework Document described the procedural and analytical approaches that DOE anticipated using to evaluate energy conservation standards for compressors, and also identified and solicited comment on various issues to be resolved in the rulemaking. DOE held that public meeting on March 3, 2014. Comments received both in response to the Framework Document and public meeting are discussed later in this document. In April 2016, DOE published a Notice of Proposed Rulemaking to address a potential test procedure for compressors.

Available at:

http://www.regulations.gov/#!documentDetail;D=EERE-2013-BT-STD-0040-0002

Available at:

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

III. General Discussion

DOE developed this proposal after considering verbal and written comments, data, and information from interested parties representing a variety of interests. The following discussion addresses issues raised by these commenters. Commenters, are listed in Table III.1.

Table III.1—Commenters and Affiliation

Commenter

Affiliation

Air-Conditioning, Heating, and Refrigeration Institute

Trade Association.

American Council for an Energy Efficient Economy

Advocacy Organization.

Appliance Standards Awareness Project

Advocacy Organization.

Association of Equipment Manufacturers

Trade Association.

Atlas Copco

Manufacturer.

California Investor Owned Utilities (Pacific Gas and Electric Company, San Diego Gas, Southern California Edison)

Utility Association.

Compressed Air and Gas Institute

Trade Association.

Edison Electric Institute

Utility Association.

G.H.S. Corporation (parent to Saylor-Beall and Sullivan-Palatek)

Manufacturer.

Ingersoll-Rand

Manufacturer.

Jenny Products, Inc

Manufacturer.

Kaeser Compressors

Manufacturer.

Natural Resource Defense Council

Advocacy Organization.

Northwest Energy Efficiency Alliance

Utility Association.

Southern California Gas Company

Utility.

Sullair Distributor Council

Manufacturer.

Sullair, LLC

Manufacturer.

William Scales, P.E

Consultant.

A. Definition of Covered Equipment

Although compressors are listed as one type of industrial equipment under 42 U.S.C. 6311(2) that DOE may regulate provided certain conditions are met, the term “compressor” is not defined in EPCA. In the Framework Document, DOE introduced a possible a definition for “compressor” which centered on a mechanical device that uses a pressure ratio of 1.1.

This value had the possible advantage of consistency with International Organization for Standardization (ISO) Technical Report 12942:2012, “Compressors—Classification—Complementary information to ISO 5390” (ISO/TR 12942:2012).

DOE has previously used both the terms “pressure ratio” and “pressure-increase ratio” to refer to the ratio of absolute discharge pressure to absolute inlet pressure. DOE notes that, while it considers the terms to mean the same thing, only “pressure ratio” will be used in this document in order to preserve clarity.

In response to the Framework Document, the American Council for an Energy-Efficient Economy (ACEEE), the Appliance Standards Awareness Project (APSP), the Northwest Energy Efficiency Alliance (NEEA), and the Alliance to Save Energy (ASE) (hereafter referred to as the Joint Commenters), as well as the National Resources Defense Council (NRDC), and the California Investor Owned Utilities (CAIOU) recommended that, with respect to pressure-increase ratio, DOE take, as a lower limit for compressors, the upper limit (1.2) for Commercial and Industrial Fans and Blowers suggested in that equipment's 2013 Framework Document.

(Joint Comment, No. 0016 at p. 1; NRDC, No. 0019 at p. 1; CAIOU, No. 0018 at p. 2) The commenters noted that this would avoid creating a coverage gap, wherein certain air processing equipment would be uncovered if its pressure ratio fell between the respective scope limit of fans/blowers and compressors. (Docket No. EERE-2013-BT-STD-0006) DOE agreed that no gap in coverage should exist between this and the fans and blowers rulemaking and proposed a definition for “compressor” with a pressure ratio of 1.3 in the test procedure NOPR as follows:

http://www.regulations.gov/#!documentDetail;D=EERE-2013-BT-STD-0006-0001

“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

greater than 1.3.

DOE proposes to use terminology consistent with ISO 1217:2009 in describing the ratio of discharge to inlet pressures as “pressure ratio,” as opposed to “pressure-increase ratio,” which is the term used in some other industry documents. However, for the purpose of this document “pressure-increase ratio” and “pressure ratio” are synonymous.

In order to objectively and unambiguously determine which equipment meets the definition of “compressor,” DOE also proposed, in the test procedure NOPR, a definition of the term “pressure ratio” as “the ratio of discharge pressure to inlet pressure, determined at full-load operating pressure . . .” Such a definition allows DOE to quantitatively establish which equipment meet the pressure ratio requirement proposed in the definition of compressor.

This definition of “pressure ratio” relies on the terms discharge pressure and inlet pressure. Definitions for these, and several other technical terms specific to testing of compressors are established in of ISO 1217:2009 and DOE proposed in the test procedure NOPR to adopt those definitions as part of incorporating by reference certain portions of ISO 1217:2009.

B. Scope of the Energy Conservation Standards in This Rulemaking

DOE notes that while the definition of “compressor,” as proposed in the test procedure NOPR, is broad, the styles of compressors to which the proposed test procedure applies would be limited to a more narrow range of equipment. Specifically, after consideration of feedback from interested parties, as well as DOE research, DOE limited the scope of analysis of this document to compressors that meet the following criteria:

• Are air compressors, as described in section III.B.1,

• Are rotary or reciprocating compressors, as described in section III.B.3,

• Are driven by a brushless electric motor, as described in section III.B.4,

• Are distributed in commerce with a compressor motor nominal horsepower greater than or equal to 1 and less than or equal to 500 horsepower (hp), as described in section III.B.4, and

• Operate at a full-load operating pressure of greater than or equal to 31 and less than or equal to 225 pounds per square inch gauge (psig), as defined in section III.B.6.

DOE notes that ultimately, based on the results of the analyses performed for this NOPR, DOE does not propose to establish energy conservation standards for reciprocating compressors in this document. Section V provides further details on this decision. Consequently, the complete scope of the energy conservation standards proposed in this rulemaking is as follows:

• Are air compressors, as described in section III.B.1,

• Are rotary compressors, as described in section III.B.3,

• Are driven by a brushless electric motor, as described in section III.B.4,

• Are distributed in commerce with a compressor motor nominal horsepower greater than or equal to 1 and less than or equal to 500 horsepower (hp), as described in section III.B.4, and

• Operate at a full-load operating pressure of greater than or equal to 31 and less than or equal to 225 pounds per square inch gauge (psig), as defined in section III.B.6.

The following subsections discuss interested party comments related to the DOE's scope of analysis and ultimate scope of proposed energy conservation standards.

1. Equipment System Boundary

In the Framework Document, DOE discussed three separate boundary levels of compressor equipment—“bare” compressor, compressor “package,” and compressed air system (CAS)—and requested comment regarding the feasibility of covering each boundary level of compressor equipment. Saylor-Beall commented that “while it might be possible to rate the air compressor package, attention needs to be given to the entire compressed air system of the end user;” whereas, Jenny Compressors (“Jenny”) stated that “covering the entire `CAS' may prove nearly impossible since many systems include components from many different manufacturers, and no two systems are the same.” (Saylor-Beall, No. 0003 at p. 2; Jenny, No. 0005 at p. 2) Compressed Air and Gas Institute (CAGI) and the Joint Commenters agreed that DOE should cover the compressor package as part of this rulemaking. (CAGI, No. 0009 at p. 3; Joint Comment, No. 0016 at p. 2) the Joint Commenters also stated that, if DOE covers the package, DOE would need to ensure companies that assemble packages from purchased components are also covered under this rulemaking. (Joint Comment, No. 0016 at p. 2-3) In this NOPR, DOE proposes to align with the scope of applicability of the test procedure NOPR and cover the compressor “package.” DOE considers covering a “bare” compressor to represent significantly lower energy savings compared to the other two compressor equipment levels. DOE also understands that, while the CAS represents the largest available energy savings, covering the CAS has significant drawbacks that weigh against its adoption as the basis for an equipment classification for the following reasons:

• Each CAS is often unique to a specific installation;

• Each CAS may include equipment from several different manufacturers; and

• A single CAS can include several different compressors, of different types, which may all have different full-load operating pressures.

Implementing a broader, CAS-based approach to compressor efficiency would require DOE to (1) establish a methodology for measuring losses in a given air-distribution network; and (2) assess what certification, compliance, or enforcement practices would be required for a large variety of system designs, and potential waiver criteria. For these reasons, DOE does not believe the CAS to be a viable equipment classification for coverage and proposes to cover only compressor “packages.”

In the test procedure NOPR, DOE proposed to use the following definition for “air compressor,” which is based on the concept of a compressor package and borrows language from the definitions used by the European Union's (EU) Lot 31 Ecodesign Study on Compressors (“Lot 31 Study,” discussed further in section IV.A.2):

“Air compressor” means 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.

Also in the test procedure NOPR, DOE proposed the following definitions which give meaning to terms used in the definition of “air compressor”:

“Bare compressor” means 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, but does not include the driver; speed-adjusting gear(s); gas processing apparatuses and piping; or compressor equipment packaging and mounting facilities and enclosures.

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

“Driver” means the machine providing mechanical input to drive a

bare compressor directly or through the use of mechanical equipment.

“Mechanical equipment” means any component of an air compressor that transfers energy from the driver to the bare compressor.

“Ancillary equipment” means any equipment distributed in commerce with an air compressor that is not a bare compressor, driver, or mechanical equipment. Ancillary equipment is considered to be part of a given air compressor, 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.

DOE seeks comment on its proposal to limit the scope of energy conservation standard proposed in this document to only equipment that is made up of a compression element (bare compressor), driver(s), mechanical equipment to drive the compressor element, and any ancillary equipment (

i.e.,

a “packaged compressor”), through the use of the defined term, “air compressors.” This is identified as Issue 2 in section VIII.E, “Issues on Which DOE Seeks Comment.”

2. Compressed Gas

Broadly, compressors are used to compress a wide variety of gases. In the Framework Document,

DOE requested comment on limiting the scope to only “air compressors” and stated that information gathered to that point indicated that non-air compressing equipment accounted for a relatively small fraction of the overall compressors market, in terms of both shipments and annual energy consumption. DOE received conflicting feedback on the topic from stakeholders. The Edison Electric Institute (EEI) recommended covering all compressor types regardless of gas type because natural gas compressor energy use is projected to increase, while CAGI agreed that DOE should cover only air compressors. (EEI, No. 0012 at p. 1-2; CAGI, No. 0009 at p. 1) The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) requested that compressors used in heating, ventilation, and air-conditioning (HVAC) equipment be specifically excluded. (AHRI No. 0015, at p. 1)

Available at:

http://www.regulations.gov/#!documentDetail;D=EERE-2013-BT-STD-0040-0001

After the publication of the Framework Document, DOE announced several new initiatives to modernize the country's natural gas transmission and distribution infrastructure, including one to explore establishing efficiency standards for natural gas compressors.

As part of that effort, DOE's Appliance Standards Program published a Request for Information (RFI), on August 5, 2014, to help determine both the feasibility of energy conservation standards for natural gas compressors and whether they are similar enough to air compressors to be considered within the scope of this rulemaking. 79 FR 25377. Additionally, DOE announced the availability of some preliminary, high-level description of the market and technology for natural gas compressors. DOE also published a notice of public meeting

(NOPM), held on December 17, 2014, to present and seek comment on the content of that data. Based upon the feedback received from the RFI, NOPM, and public meeting, DOE opted to consider natural gas compressors separately from air compressors. (Docket No. EERE-2014-BT-STD-0051)

See:

http://energy.gov/articles/department-energy-announces-steps-help-modernize-natural-gas-infrastructure

Available at:

http://www.regulations.gov/?s#!documentDetail;D=EERE-2014-BT-STD-0051-0005

Regarding refrigerant compressors, DOE considers refrigerant compressors to have the same basic function as air compressors in that they both compress a working fluid to a higher pressure, but with the working fluid of refrigerant compressors being refrigerant instead of air. Refrigerant compressors are usually only included in equipment where cooling or heating is required, such as heating, ventilation, air-conditioning and refrigeration (HVACR) equipment. Similar to natural gas compressors, DOE has determined that refrigerant compressors serve a specific and unique application and also necessitate unique standards. As a result, DOE has opted not to consider refrigerant compressors in this rulemaking.

Furthermore, DOE's research found no large market segments or applications for compressor equipment used on gases other than air or natural gas. Information gathered during confidential manufacturer interviews indicated that non-air and non-natural gas compressing equipment represented relatively low sales volume and annual energy consumption.

Because air compressors comprise a significant portion of the compressor market and DOE intends to consider natural gas equipment as part of a separate rulemaking,

DOE proposes to consider standards for only air compressors in this rulemaking. DOE believes that compressors for other fluids serve different applications and are technically very different equipment than air compressors. As a result, compressors for gases other than air would likely require separate test procedures and energy conservation standards analyses. Consequently, DOE proposes to align with the scope of applicability of the test procedure NOPR, and limit the scope of energy conservation standards to only compressors that are designed to compress air and that have inlets open to the atmosphere or other source of air, through the use of the defined term, “air compressors.” As discussed in Section III.B.1, DOE proposed a definition for the term “air compressor” in the test procedure NOPR.

Docket viewable here:

http://www.regulations.gov/#!docketDetail;D=EERE-2014-BT-STD-0051

DOE seeks comment on its proposal to limit the scope of energy conservation standard proposed in this document to only compressors that are designed to compress air and that have inlets open to the atmosphere or other source of air, through the use of the defined term, “air compressors.” This is identified as Issue 3 in section VIII.E, “Issues on Which DOE Seeks Comment.”

3. Compression Principle

Compressor equipment can be classified by compression principle, and on that basis can include dynamic compressors, rotary compressors, and reciprocating compressors. In the Framework Document, DOE offered definitions for each:

“Dynamic compressor” means “a compressor in which the gas pressure increase is achieved in continuous flow essentially by increasing its kinetic energy in the flow path of the machine due to acceleration to the high velocities by mechanical action of blades placed on a rapid rotating wheel and further transformation of the kinetic energy into the potential energy of the elevated pressure by successive deceleration of the said flow.” The definition for dynamic compressor is consistent with the definition included in ISO/TR 12942:2012 and aligns with industry standards.

“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.” The definition for rotary compressor is consistent with the definition included in ISO/TR 12942:2012 and aligns with industry standards.

“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).” The definition for reciprocating compressor is consistent with the definition included in ISO/TR 12942:2012 and aligns with industry standards.

DOE's test procedure NOPR proposes those definitions for “rotary compressor,” and “reciprocating compressor,” and added a proposed definition for “positive-displacement compressor.” The test procedure NOPR did not propose a definition for “dynamic compressor,” as no test methods were proposed for equipment commonly referred to as “dynamic compressors.” In the test procedure NOPR, the term “positive-displacement compressor” is proposed 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 Framework Document, several stakeholders agreed that DOE should cover all three compressor types. (Joint Comment, No. 0016 at p. 2; CAGI, No. 0009 at p. 1) Scales commented that DOE should focus on centrifugal and rotary screw compressors above 350-hp. (W. Scales, No. 0020 at p. 1) DOE also received annual shipments data in industry stakeholder submittals. This shipments data are discussed in detail in section IV.G. DOE used these data to estimate the overall size of the air compressors market. The shipments data for 2013 provided to DOE suggest that rotary and reciprocating compressors account for the majority of the air compressors market by units shipped. By contrast, dynamic compressors account for fewer than 300 total units shipped, or roughly one percent of the total market.

DOE research indicated that dynamic compressors are typically larger in power than positive displacement compressors, and commonly engineered specifically for an order. Due to specialization and size, little cost and performance data are publicly available, as both will vary from unit to unit. Further, DOE found that the standard international test procedure for dynamic compressors, ISO 5389, was considered complicated and not widely used by industry. This fact may also contribute to the general lack of publicly available performance data.

Due to the lack of available data and relatively small market share of dynamic compressors, DOE did not include dynamic compressors within the scope of analysis of this energy conservation standards rulemaking; rather, DOE aligned with the scope of applicability of the test procedure NOPR, and analyzed and considered standards for rotary and reciprocating compressors. Although DOE considered reciprocating compressors within its scope of analysis, based on the results of DOE's analyses, DOE does not propose to establish standards for reciprocating compressors in this document. Consequently, in this NOPR, DOE proposes to establish energy conversation standards for only rotary compressors. Section V of this document provides further details on this decision. DOE notes that it may explore in the future whether standards for reciprocating or dynamic compressors are warranted.

4. Driver Type

Compressors can be powered using several types of drivers, commonly including electric motors and internal combustion engines. Electric motor-driven equipment may use either single-phase or three-phase electric motors. Combustion engine-driven air compressors can be powered by using different kinds of fuels, commonly including diesel, gasoline, and natural gas. In the Framework Document, DOE considered establishing standards for compressors regardless of driver type and requested stakeholder comments.

a. Combustion Engines

DOE received varying comments regarding the inclusion of combustion engine

driven compressors. Jenny, the Association of Equipment Manufacturers (AEM), and Sullair recommended excluding engine-driven compressors due to the burden imposed by current emissions regulations and overall low energy consumption by these products. (Jenny, No. 0005 at p. 2; AEM, No. 0011 at p. 1-2; Sullair, No. 0013 at p. 2) EEI and the CAIOU urged DOE to include engine-driven compressors to avoid creating a market trend towards engine-driven compressors. (EEI, No. 0012 at p. 2-3; CAIOU, No. 0018 at p. 2) The Joint Commenters recommended that DOE examine engine-driven compressors to evaluate possible energy savings but noted that generally they are used in low-duty cycle applications. (Joint Comment, No. 0016 at p. 2)

For the purposes of this document, the term “engine” means “combustion engine,” equipment which can convert chemical energy into mechanical energy by combusting fuel in the presence of air.

Engine-driven air compressors are generally portable and designed to be used in environments where access to electricity is limited or non-existent, particularly at the current or voltage levels required by comparable electric motor-driven compressors. Engine-driven compressors are also typically used as on-demand units, with a low duty cycle and annual energy consumption. Additionally, engine-driven compressors, by nature of their portability, are less able to be optimized for a specific set of operating conditions, which may harm efficiency relative to a stationary unit that is designed or selected with a specific load profile in mind. Consequently, engine-driven and electric motor-driven compressors do not serve the same applications and are not mutual substitutes.

DOE is aware that engine-driven compressors are currently covered by the Environmental Protection Agency's Tier 4 emissions regulations (40 CFR 1039).

DOE understands that these Tier 4 regulations have resulted in market-wide redesigns for the engines typically used in these compressors, which has required compressor manufacturers to redesign some of their own equipment. Based on the relatively lower annual energy consumption, non-overlapping applications of motor- and engine-driven equipment, and potentially competing priorities between current emissions regulations and potential energy conservation standards, DOE proposes to align with the scope of applicability of the test procedure NOPR and not include engine-driven equipment in the scope of this energy conservation standards this rulemaking. DOE may explore in the future whether standards for engine-driven units are warranted.

See also:

http://www.epa.gov/otaq/nonroad-diesel.htm

b. Motor Phase Count

In the Framework Document, DOE also considered excluding single-phase electric motor-driven equipment. Stakeholders generally agreed with excluding these products. (Saylor-Beall, No. 0003 at p. 2; CAGI, No. 0009 at p. 3; Joint Comment, No. 0016 at p. 2). Other stakeholders commented that compressors under 10-hp are generally packaged with single-phase electric motors. (CAGI, No. 0009 at p. 3; Jenny, No. 0005 at p. 2). Saylor-Beall commented that, particularly for compressors under 5-hp, three-phase shipment volumes are low. (Saylor-Beall, No. 0003 at p. 2) The Lot 31 Study estimated that single-phase compressors in the EU represent less than one

percent of total compressor annual energy consumption. DOE research suggests that the U.S. compressors market exhibits similar trends.

However, DOE is aware that some reciprocating compressors can be packaged with either single- or three-phase electric motors. Establishing energy conservation standards for only one variation of a shared platform (

e.g.,

three-phase motor-driven reciprocating compressors) could create a market shift towards less efficient single-phase motor-driven reciprocating compressors. Consequently, in this document, DOE analyzed energy conservations standards for both single-phase and three-phase reciprocating compressors. Ultimately, based on the results of its analyses, DOE does not propose to establish standards for either single- or three-phase motor-driven reciprocating compressors in this document.

For rotary compressors, DOE understands that a very small fraction of the market may be shipped as single-phase. DOE currently has no data on the performance of single-phase rotary equipment. If the applicable single-phase motors are less efficient than their three-phase counterparts, it is possible that single-phase compressor packages may be less efficient as well.

In the absence of more information on the relative cost and efficiency of single- and three-phase compressors, DOE wishes to avoid the risk of a substitution incentive. As a result, DOE proposes, in this document, to consider standards for single-phase and three-phase rotary compressors in this rulemaking.

DOE requests comment on its proposal to consider standards for both single- and three-phase compressor equipment. DOE also requests comment on any market trends that may affect the efficiency of such equipment in the future. DOE requests data that may aid in characterizing the relative cost and performance of equipment of different motor phase counts, so that DOE can better evaluate whether a substitution incentive is likely to be created. This is identified as Issue 4 in section VIII.E, “Issues on Which DOE Seeks Comment.”

c. Styles of Electric Motor

DOE is aware that some small compressors intended for very low duty-cycles may be manufactured with motors which use sliding electric contacts, or “brushes.” Although brushes are simple to control and inexpensive to construct, they are rarely used in applications with significant operating hours, for several reasons. First, brushes generally impose a reduction in efficiency, relative to brushless technology, and are thereby suitable only for applications with low duty cycles. Second, brushes wear and require replacement at regular intervals, which may pose risk of inducing costly downtime in an industrial process. Third, brushes may create electrical arcing, rendering them unsuitable for certain industrial environments where combustible or explosive gases or dust may exist. Finally, brushes may create greater acoustic noise than brushless technology, which can be viewed as a form of utility to the end user.

All of these factors limit the applications for which any compressors distributed in commerce with brushed motors are suitable. However, DOE recognizes the applications for which brushed motors are appropriate as a unique market segment serving specific applications where, in particular, operating life and durability are not important criteria.

DOE also notes that compressors sold with brushed motors play a niche role in the market and, as a result, DOE does is electing to focus on the dominant brushless motor technology in developing the energy conservation standards proposed herein. Consequently, DOE proposes to align with the scope of applicability of the test procedure NOPR, and limit the scope of energy conservation standards to only those compressors that are driven by brushless motors.

DOE may consider energy conservation standards for compressors sold with brushed electric motors as part of a separate, future, rulemaking, if it determines such actions are warranted.

In the test procedure NOPR, DOE proposed to define “brushless electric motor” as a machine that coverts electrical power into rotational mechanical power without use of sliding electrical contacts.” DOE considers “brushless” motors to include, but not be limited to, what are commonly known as “induction,” “brushless DC,” “permanent magnet,” “electrically commutated,” and “reluctance” motors. The term “brushless” motors would not include what are commonly known as “brushed DC” and “universal” motors.

5. Equipment Capacity

Compressors are sold in a very wide range of capacities. Compressor capacity refers to the overall rate at which a compressor can perform work. Although the ultimate end-user requirement is a specific output volume flow rate of air at a certain pressure, industry typically describes compressor capacity in terms of the “nominal” horsepower of the motor. As a result, in the test procedure NOPR, DOE proposed to consider equipment capacity in terms of the “nominal” horsepower of the motor with which the compressor is distributed in commerce.

However, DOE recognizes that although the term nominal motor horsepower is commonly used within the compressor industry, it is not explicitly defined in ISO 1217:2009. To alleviate any ambiguity associated with these terms, DOE proposed in the test procedure NOPR to define the term “compressor motor nominal horsepower” to mean the motor horsepower of the electric motor, as determined in accordance with the applicable procedures in subpart B and subpart X of 10 CFR 431, with which the rated compressor is distributed in commerce.

In the Framework Document, DOE discussed limiting the scope of applicability based on equipment capacity as measured in horsepower (hp) to units with capacities of between 1 to 500 hp in order to align the scope of compressor standards with the scope of DOE's electric motors standards.

See

10 CFR 431.25. Commenters generally recommended expanding the scope to cover compressors larger than 500 hp, in order to capture the maximum possible energy savings. (EEI, No. 0012 at p. 3; Joint Comment, No. 0016 at p. 2; Natural Resource Defense Council (NRDC), No. 0019 at p. 1; CA IOUs, No. 0018 at p. 2) Jenny and the Joint Commenters also recommended that the lower hp limit should be increased due to the low annual energy usage of compressors under 10 hp. (Jenny, No. 0005 at p. 3; Joint Comment, No. 0016 at p. 2)

DOE considered the comments of interested parties regarding the range of equipment capacities. Shipment data, broken down by rated capacity and compression principle (

i.e.,

rotary, reciprocating, and dynamic) indicate that units above 400 hp represent less than 1 percent of the rotary market and virtually none of the reciprocating market. Although it is possible to build positive displacement compressors above 500 hp, shipments are very low and the equipment is typically custom-ordered. DOE notes that, above 500 hp, dynamic compressors are the dominant choice for industrial compressed air service. Furthermore, as discussed in section III.B.3, little performance data is available on units with capacities greater than 500 hp. Due to this lack of data and the small market share for positive displacement compressors with capacities greater than 500 hp, DOE proposes to align with the scope of applicability of the test procedure NOPR and limit the scope of this energy conservation rulemaking to compressors with a compressor motor nominal horsepower of greater than or equal to 1 and less than or equal to 500 hp. Based on available shipment data,

DOE's proposal is expected to cover nearly the entirety of the rotary and reciprocating compressor market.

DOE requests comment on the proposal to include only compressors with a compressor motor nominal horsepower of greater than or equal to 1 and less than or equal to 500 within the scope of this energy conservation standard. This is identified as Issue 5 in section VIII.E, “Issues on Which DOE Seeks Comment.”

6. Full-Load Operating Pressure

Because different compressed air applications require air to be delivered at specific pressure ranges, output pressure is a critical characteristic in equipment selection and compressed air system design. DOE notes that there may be several ways to characterize output pressure. In the test procedure NOPR, DOE proposed to use “full-load operating pressure” as the most relevant metric, where “full-load operating pressure” is a declared pressure, which must be greater than or equal to 90 percent and less than or equal to 100 percent of the maximum full-flow operating pressure.

The test procedure NOPR also proposed a definition and test method for finding “maximum full-flow operating pressure,” which is a term needed to characterize “full-load operating pressure.” DOE proposed that “maximum full-flow operating pressure” means the maximum discharge pressure at which the compressor is capable of operating.

Industry convention holds that when output pressure is cited absolutely or in “gauge” (

i.e.,

not as a ratio), the input pressure is assumed to be that at which a compressor would ingest ambient air at sea level.

“Gauge” pressure, whether given in U.S. or metric units, normally means “the amount above intake pressure.” A compressor described as delivering 100 psig,

then, can be assumed to produce 114.7 psi in absolute terms when operated in a standard atmosphere. Gauge pressure is commonly used because for most purposes, the pressure differential is more critical to the application than the absolute measurement. Another commonly-used pressure descriptor is “pressure ratio.” Simply, it is the ratio of the absolute output (discharge) and absolute input (suction) pressures. For compressors operating in the same conditions, this value expresses identical information.

Commonly approximated in pounds per square inch (psi) as 14.7.

i.e.,

psi in gauge terms.

In response to discussions of operating pressure in the Framework Document, CAGI provided the following detailed breakdown of output pressures in the rotary compressors market. (CAGI, No. 0030 at p. 4):

• Approximately 4.4 to 30 pounds per square inch gauge (psig) (pressure ratio greater than 1.3 and less than or equal to 3.0): The compressors industry generally refers to these products as blowers—a term DOE is considering defining as part of its fans and blowers rulemaking (Docket No. EERE-2013-BT-STD-0006). The majority of these units are typically distributed in commerce as bare compressors and do not include a driver, mechanical equipment, or controls.

• 31 to 79 psig (pressure ratio greater than 3.1 and less than or equal to 6.4): There are relatively few compressed air applications in this pressure range, contributing to both low product shipment volume and low annual energy consumption.

• 80 to 139 psig (pressure ratio greater than 6.4 and less than or equal to 10.5): This range represents the majority of general compressed air applications, shipments, and annual energy use.

• 140 to 215 psig (pressure ratio greater than 10.5 and less than or equal to 15.6): This range represents certain specialized applications, relatively lower sales volumes and annual energy consumption when compared to the 80 to 139 psig rotary compressor segment.

• Greater than 215 psig (pressure ratio greater than 15.6): This range represents even more specialized applications, which require highly engineered rotary compressors that vary based on each application.

DOE did not receive any additional information that separated the market of reciprocating compressors by pressure. According to the Lot 31 preparatory study final report,

single- and two-stage reciprocating compressors typically operate from 0.8 to 12 bar (12 to 174 psig; pressure ratio 1.8 to 13), and multi-stage reciprocating compressors typically operate from 12 to 700 bar (174 to 10,152 psig; pressure ratio 13 to 701). However, based on market research and discussions with various compressor manufacturers, DOE believes that pressure ranges for reciprocating compressors are similar to rotary compressors.

The European Union regulatory body is also exploring standards for compressors, which is part of a product group which it refers to as “Lot 31.” For copies of the EU Lot 31 Final Report of a study on Compressors please go to:

www.regulations.gov/#!documentDetail;D=EERE-2013-BT-STD-0040-0031

. For copies of the EU Lot 31 draft regulation:

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

In the test procedure NOPR, DOE proposed defining a “compressor” as equipment with a pressure ratio exceeding 1.3. Furthermore, in the test procedure NOPR, DOE proposed that the test procedure only be applicable to compressors with full-load operating pressures greater than or equal to 31 psig and less than or equal to 225 psig. In this document, DOE proposes to align with the scope of applicability of the test procedure NOPR, and limit the scope of energy conversation standards to compressors with full-load operating pressures of between 31 and 225 psig (pressure ratios greater than ~3.1 and less than or equal to 16.3). DOE notes that while some commenters suggested an upper limit of 215 psig, full-load operating pressure values may be generated differently by each manufacturer and it is not clear that they are completely comparable between manufacturers.

For example, a product listed at 215 psig from one manufacturer may compete with a product listed at 217 psig from another, which may compete with one listed at 212 psig from a third. Although DOE's proposed test procedure seeks to eliminate this issue, DOE must still account for the current lack of consistent pressure rating methodology in the compressor industry. As a result, DOE proposes to adopt an upper limit of 225 psig to include the majority of non-special purpose equipment DOE could identify on the market. Compressor equipment with full-load operating pressures below 31 psig and above 225 psig generally represent a different equipment type and serve applications that do not often overlap with the 31-225 psig compressor market, and do not represent a significant volume of sales.

DOE notes that there is no universally accepted procedure for establishing full-load operating pressure and, thus, no assurances that values are comparable.

C. Test Procedure

DOE is currently conducting a rulemaking to establish a uniform test procedure for determining the energy efficiency of compressors. DOE proposed a test method for calculating the package isentropic efficiency of compressors, by measuring the delivered power (in the form of compressed air) and the electric input power to the motor or controls. DOE proposed that the methods be based on International Organization for Standardization (ISO) Standard 1217:2009, “Displacement

compressors—Acceptance tests,” (hereinafter referred to as “ISO 1217:2009”) with modifications. In response to the Framework, Jenny recommended that compressors not be separated based on rated horsepower, as they do not always run at full horsepower. (Jenny, No. 0005 at p. 2) The Joint Commenters recommended that a metric using both package specific power

and package isentropic efficiency be used to provide useful information for consumers. (Joint Comment, No. 0016 at p. 3)

In the test procedure NOPR, DOE proposes to define the term “package specific power” as “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 prescribed in § 431.344.”

In the test procedure NOPR, DOE proposed that the energy conservation standards for compressors be expressed in terms of fixed-speed package isentropic efficiency (η

isen,FS

) for fixed-speed compressors and variable-speed package isentropic efficiency (η

isen,VS

) for variable-speed compressors. The terms η

isen,FS

and η

isen,VS

describe the power required for an ideal isentropic compression process, divided by the actual input power of the packaged compressor. The η

isen,FS

considers this ratio at full-load operating pressure and η

isen,VS

considers this ratio at a weighted-average of full-load and part-load operating pressures. The metrics are defined in Equations 1 and 2 as follows:

EP19MY16.000

Where:

• η

isen,FS

is the package isentropic efficiency at full-load operating pressure;

•

isen,FL

is the isentropic power required for compression at full-load operating pressure, as determined in accordance with the DOE test procedure. This metric applies only to fixed-speed compressors, and;

•

real,FL

is the packaged compressor power input at full-load operating pressure, as tested in accordance with the DOE test procedure. This metric applies only to fixed-speed compressors.

EP19MY16.001

Where:

• η

isen,VS

is the package isentropic efficiency as applied to variable-speed compressors;

•

isen,i

is the isentropic power required for compression at rating point i, as determined in accordance with the DOE test procedure. This metric applies only to variable-speed compressors;

•

real,i

is the packaged compressor power input at rating point i, as tested in accordance with the DOE test procedure. This metric applies only to variable-speed compressors;

• ω

is the weighting at each rating point, as described in the DOE test procedure; and

•

are the load points corresponding to 40-, 470-, and 100-percent of the full-load actual volume flow rate.

The measured value of package isentropic efficiency would then be compared to DOE's proposed energy conservation standard. A value greater than the proposed standard indicates that the compressor exceeds the minimum efficiency standard, while a value lower than the proposed standard indicates that the compressor fails to meet the proposed standard.

D. Technological Feasibility

1. General

In each energy conservation standards rulemaking, DOE conducts a screening analysis based on information gathered on all current technology options and prototype designs that could improve the efficiency of the products or equipment that are the subject of the rulemaking. As the first step in such an analysis, DOE develops a list of technology options for consideration in consultation with manufacturers, design engineers, and other interested parties. DOE then determines which of those means for improving efficiency are technologically feasible. DOE considers technologies incorporated in commercially-available products or in working prototypes to be technologically feasible. See,

e.g.,

10 CFR part 430, subpart C, appendix A, section 4(a)(4)(i).

After DOE has determined that particular technology options are technologically feasible, it further evaluates each technology option in light of the following additional screening criteria: (1) Practicability to manufacture, install, and service; (2) adverse impacts on product utility or availability; and (3) adverse impacts on health or safety. See,

e.g.,

10 CFR part 430, subpart C, appendix A, section 4(a)(4)(ii)-(iv). Additionally, DOE generally does not include in its analysis any proprietary technology that is a unique pathway to achieving a certain efficiency level. Section IV.B of this document discusses the results of the screening analysis for compressors, particularly with respect to the designs DOE considered, those it screened out, and those serving as the basis for the proposed standards being considered. For further details on the screening analysis for this rulemaking, see chapter 4 of the NOPR technical support document (TSD).

2. Maximum Technologically Feasible Levels

When DOE proposes to adopt a new standard for a type or class of covered product, it must determine the maximum improvement in energy efficiency or maximum reduction in energy use that is technologically feasible for such product. (42 U.S.C. 6295(p)(1) and 6316(a)) Accordingly, in the engineering analysis, DOE determined the maximum technologically feasible (“max-tech”) improvements in energy efficiency for compressors, using the design parameters for the most efficient products available on the market or in working prototypes. The max-tech levels that DOE determined for this rulemaking are described in section IV.C of this proposed rule and in chapter 5 of the NOPR TSD.

E. Compliance Date

DOE estimates that any final rule would publish in late 2016. Therefore, DOE has used an estimated compliance date for this rulemaking in late 2021.

DOE's analysis begins in the first full year of compliance with new standards, 2022.

F. Energy Savings

1. Determination of Savings

For each trial standard level (TSL), DOE projected energy savings from applying the TSL to compressors purchased in the 30-year period that begins in the first full-year of compliance with the proposed standards (2022-2051).

The savings are measured over the entire lifetime of compressors purchased during this 30-year period. DOE quantified the energy savings attributable to each TSL as the difference in energy consumption between each standards case and the no-new-standards case. The no-new-standards case represents a projection of energy consumption that reflects how the market for a product would likely evolve in the absence of new energy conservation standards.

Each TSL is comprised of specific efficiency levels for each product class. The TSLs considered for this NOPR are described in section V.A. DOE conducted a sensitivity analysis that considers impacts for products shipped in a 9-year period.

DOE used its national impact analysis (NIA) spreadsheet model to estimate national energy savings (NES) from potential for compressors. The NIA spreadsheet model (described in section IV.H of this document) calculates energy savings in terms of site energy, which is the energy directly consumed by products at the locations where they are used. Based on the site energy, DOE calculates NES)in terms of primary energy savings at the site or at power plants, and also in terms of full-fuel-cycle (FFC) energy savings. The FFC metric includes the energy consumed in extracting, processing, and transporting primary fuels (

i.e.,

coal, natural gas, petroleum fuels), and thus presents a more complete picture of the impacts of energy conservation standards.

DOE's approach is based on the calculation of an FFC multiplier for each of the energy types used by covered products or equipment. For more information on FFC energy savings, see section IV.H.1 of this document.

The FFC metric is discussed in DOE's statement of policy and notice of policy amendment. 76 FR 51282 (Aug. 18, 2011), as amended at 77 FR 49701 (Aug. 17, 2012).

2. Significance of Savings

To adopt any new or amended standards for a covered product, DOE must determine that such action would result in “significant” energy savings. (42 U.S.C. 6295(o)(3)(B) and 6316(a)) Although the term “significant” is not defined in the Act, the U.S. Court of Appeals for the District of Columbia Circuit, in

Natural Resources Defense Council

Herrington,

768 F.2d 1355, 1373 (D.C. Cir. 1985), opined that Congress intended “significant” energy savings in the context of EPCA to be savings that were not “genuinely trivial.” The energy savings for all of the TSLs considered in this rulemaking, including the proposed standards (presented in section V), are nontrivial, and, therefore, DOE considers them “significant” within the meaning of section 325 of EPCA.

G. Economic Justification

1. Specific Criteria

As noted in this preamble, EPCA provides seven factors to be evaluated in determining whether a potential energy conservation standard is economically justified. (42 U.S.C. 6295(o)(2)(B)(i)(I)-(VII) and 6316(a)) The following sections discuss how DOE has addressed each of those seven factors in this rulemaking.

a. Economic Impact on Manufacturers and Consumers

DOE considers the economic impacts of its potential standards on both manufacturers and consumers. See 42 U.S.C. 6295(o)(2)(B)(i)(I) and 6316(a). In determining the impacts of a potential amended standard on manufacturers, DOE conducts a manufacturer impact analysis (MIA), as discussed in section IV.J. DOE first uses an annual cash-flow approach to determine the quantitative impacts. This step includes both a short-term assessment—based on the cost and capital requirements during the period between when a regulation is issued and when entities must comply with the regulation—and a long-term assessment over a 30-year period. The industry-wide impacts analyzed include: (1) Industry net present value (INPV), which values the industry on the basis of expected future cash flows; (2) cash flows by year; (3) changes in revenue and income; and (4) other measures of impact, as appropriate. Second, DOE analyzes and reports the impacts on different types of manufacturers, including impacts on small manufacturers. Third, DOE considers the impact of standards on domestic manufacturer employment and manufacturing capacity, as well as the potential for standards to result in plant closures and loss of capital investment. Finally, DOE takes into account cumulative impacts of various DOE regulations and other regulatory requirements on manufacturers.

For individual consumers, measures of economic impact include the changes in LCC and payback period (PBP) associated with new or amended standards. These measures are discussed further in the following section. For consumers in the aggregate, DOE also calculates the national net present value of the consumer costs and benefits expected to result from particular standards. DOE also evaluates the impacts of potential standards on identifiable subgroups of consumers that may be affected disproportionately by a standard.

b. Savings in Operating Costs Compared to Increase in Price (LCC and PBP)

DOE considers the savings in operating costs throughout the estimated average life of the covered equipment in the type (or class) compared to any increase in the price, initial charges, or maintenance expenses of that equipment that are likely to result from a standard. (42 U.S.C. 6295(o)(2)(B)(i)(II) and 6316(a)) DOE conducts this comparison in its LCC and PBP analysis.

The LCC is the sum of the purchase price of a product (including its installation) and the operating expense (including energy, maintenance, and repair expenditures) discounted over the lifetime of the product. The LCC analysis requires a variety of inputs, such as product prices, product energy consumption, energy prices, maintenance and repair costs, product lifetime, and discount rates appropriate for consumers. To account for uncertainty and variability in specific inputs, such as product lifetime and discount rate, DOE uses a distribution of values, with probabilities attached to each value.

The PBP is the estimated amount of time (in years) it takes consumers to recover the increased purchase cost (including installation) of a more-efficient product through lower operating costs. DOE calculates the PBP by dividing the change in purchase cost due to a more stringent standard by the change in annual operating cost for the year that standards are assumed to take effect.

For its LCC and PBP analysis, DOE assumes that consumers will purchase the covered products in the first year of compliance with amended standards. The LCC savings for the considered efficiency levels are calculated relative to the case that reflects projected market trends in the absence of amended standards. DOE's LCC and PBP analysis is discussed in further detail in section IV.F.

c. Energy Savings

Although significant conservation of energy is a separate statutory requirement for adopting an energy conservation standard, EPCA requires

DOE, in determining the economic justification of a standard, to consider the total projected energy savings that are expected to result directly from the standard. (42 U.S.C. 6295(o)(2)(B)(i)(III) and 6316(a)) As discussed in section III.D, DOE uses the NIA spreadsheet models to project national energy savings.

d. Lessening of Utility or Performance of Equipment

In establishing equipment classes and in evaluating design options and the impact of potential standard levels, DOE evaluates potential standards that would not lessen equipment utility or performance. (42 U.S.C. 6295(o)(2)(B)(i)(IV) and 42 U.S.C. 6316) Based on data available to DOE, the standards proposed in this document would not reduce the utility or performance of the products under consideration in this rulemaking.

e. Impact of Any Lessening of Competition

EPCA directs DOE to consider the impact of any lessening of competition, as determined in writing by the Attorney General, which is likely to result from a proposed standard. (42 U.S.C. 6295(o)(2)(B)(i)(V) and 6316(a)) It also directs the Attorney General to determine the impact, if any, of any lessening of competition likely to result from a proposed standard and to transmit such determination to the Secretary within 60 days of the publication of a proposed rule, together with an analysis of the nature and extent of the impact. (42 U.S.C. 6295(o)(2)(B)(ii) and 6316(a)) DOE will transmit a copy of this proposed rule to the Attorney General with a request that the Department of Justice (DOJ) provide its determination on this issue. DOE will include the Attorney General's response in the docket for this rulemaking and will respond to the Attorney General's determination in the final rule.

f. Need for National Energy Conservation

DOE also considers the need for national energy conservation in determining whether a new or amended standard is economically justified. (42 U.S.C. 6295(o)(2)(B)(i)(VI) and 6316(a)) The energy savings from the proposed standards are likely to provide improvements to the security and reliability of the nation's energy system. Reductions in the demand for electricity also may result in reduced costs for maintaining the reliability of the nation's electricity system. DOE conducts a utility impact analysis to estimate how standards may affect the nation's needed power generation capacity, as discussed in section IV.M.

The proposed standards also are likely to result in environmental benefits in the form of reduced emissions of air pollutants and greenhouse gases associated with energy production and use. DOE conducts an emissions analysis to estimate how potential standards may affect these emissions, as discussed in section IV.K; the emissions impacts are reported in section V.L of this document. DOE also estimates the economic value of emissions reductions resulting from the considered TSLs, as discussed in section IV.L.

g. Other Factors

In determining whether an energy conservation standard is economically justified, DOE may consider any other factors that the Secretary deems to be relevant. (42 U.S.C. 6295(o)(2)(B)(i)(VII) and 6316(a)) To the extent there are other factors relevant to evaluating whether the proposed standards are economically justified, DOE may consider other factors that fall outside of the categories discussed above.

2. Rebuttable Presumption

As set forth in 42 U.S.C. 6295(o)(2)(B)(iii) and 6316(a), EPCA creates a rebuttable presumption that an energy conservation standard is economically justified if the additional cost to the consumer of a product that meets the standard is less than three times the value of the first year's energy savings resulting from the standard, as calculated under the applicable DOE test procedure. DOE's LCC and PBP analyses generate values used to calculate the effects that proposed energy conservation standards would have on the payback period for consumers. These analyses include, but are not limited to, the 3-year payback period contemplated under the rebuttable-presumption test. In addition, DOE routinely conducts an economic analysis that considers the full range of impacts to consumers, manufacturers, the nation, and the environment. See 42 U.S.C. 6295(o)(2)(B)(i) and 6316(a). The results of this analysis serve as the basis for DOE's evaluation of the economic justification for a potential standard level (thereby supporting or rebutting the results of any preliminary determination of economic justification). The rebuttable presumption payback calculation is discussed in section V.B.1.c of this proposed rule.

H. Compressor Industry Recommendation

DOE received a comment on proposed standards and test methods from CAGI, the primary compressor trade association. That recommendation is summarized below.

DOE responds to the points made within the comment in the appropriate sections of this document.

Available at:

http://www.regulations.gov/#!documentDetail;D=EERE-2013-BT-STD-0040-0030

1. Summary

CAGI recommended making mandatory the use of standardized test methods and reporting formats that are presently voluntary. With respect to scope, CAGI suggested that DOE address lubricated, rotary compressors operating from 80-139 psig and with “flows” from 35 to 2000 cfm. (CAGI, No. 0030 at p. 1) The benefits, according to CAGI, include energy savings, regulatory simplicity, and granting industry the ability to continue energy efficiency efforts undisrupted.

Id.

2. Specific Provisions

CAGI makes the following comments and recommendations in its submission:

• With respect to European efforts, that the Lot 31 Study made use of CAGI-published data, and that those efforts can inform the work being done by DOE. (CAGI, No. 0030 at p. 3)

• The biggest part of the compressed air industry serves “general industrial air” customers which primarily use rotary equipment, rated from 80-139 psig and 35-2000 cfm, and driven by electric motors rated from 10 to 500-hp. (CAGI, No. 0030 at p. 3)

• There is little risk of substitution for compressors if DOE opts to leave certain market segments unregulated. Customer needs generally define which equipment is purchased. (CAGI, No. 0030 at p. 4)

• Lubricant-free

equipment is used in more specialized applications and carries significantly smaller market size. As a result, regulation carries smaller potential to save energy and greater risk of negative impact to manufacturers and consumers. (CAGI, No. 0030 at p. 5) DOE, like EU Lot 31, should not include lubricant-free equipment.

Although industry frequently uses the term “oil-free” to describe equipment with substances injected during the compression process, not all of the substances used are oils, in the chemical sense, and so DOE will use the term “lubricant-free” to refer to such equipment.

• Reciprocating compressors should not be included in the rulemaking. Low duty cycle and small average capacity means that energy savings potential is

significantly lower than for other compressor types. The market is highly fragmented, with many assemblers purchasing parts from a variety of suppliers. Finally, low production volumes could generate large negative impacts to manufacturers forced to redesign in order to comply with a standard. (CAGI, No. 0030 at p. 6)

• CAGI supplies proposed definitions for “basic package compressor,” “standard air compressor,” and “rotary standard air compressor.” (CAGI, No. 0030 at p. 8)

• With respect to measurement, CAGI proposes use of ISO 1217:2009 for both fixed- (Annex C) and variable-speed (Annex E) equipment. For variable-speed equipment, CAGI proposes a weighted average performance across certain load points, also proposed for use by EU Lot 31. (CAGI, No. 0030 at p. 8-9)

• In CAGI's view, standardizing measurement and data publication will be sufficient to drive continued energy conservation in compressors. CAGI asserts that the market already self-establishes a de facto minimum performance standard, and attempts by DOE to introduce one may be counterproductive to both energy savings and manufacturer welfare. (CAGI, No. 0030 at p. 9)

IV. Methodology and Discussion of Related Comments

This section addresses the analyses DOE has performed in this rulemaking for compressors. Separate subsections address each component of DOE's analyses.

DOE used several analytical tools to estimate the impact of the standards proposed in this document. The first tool is a spreadsheet that calculates the LCC savings and PBP of potential amended or new energy conservation standards. The national impacts analysis uses a second spreadsheet set that provides shipments forecasts and calculates national energy savings and net present value of total end user costs and savings expected to result from potential energy conservation standards. DOE uses the third spreadsheet tool, the Government Regulatory Impact Model (GRIM), to assess manufacturer impacts of potential standards. These spreadsheet tools are available at

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

. Additionally, DOE used output from the latest version of EIA's

Annual Energy Outlook

(

AEO),

a widely known energy forecast for the United States, for the emissions and utility impact analyses.

A. Market and Technology Assessment

DOE develops information in the market and technology assessment that provides an overall picture of the market for the equipment concerned, including the purpose of the equipment, the industry structure, manufacturers, market characteristics, and technologies used in the equipment. This activity includes both quantitative and qualitative assessments, based primarily on publicly-available information (

e.g.,

manufacturer specification sheets, and industry publications) and data submitted by manufacturers, trade associations, and other stakeholders. The subjects addressed in the market and technology assessment for this rulemaking include: (1) A determination of the scope of the rulemaking and equipment classes; (2) manufacturers and industry structure; (3) existing efficiency programs; (4) shipments information; (5) market and industry trends; and (6) technologies or design options that could improve the energy efficiency of compressors. The key findings of DOE's market assessment are summarized below. See chapter 3 of the NOPR TSD for further discussion of the market and technology assessment.

1. Equipment Classes

When evaluating and establishing energy conservation standards, DOE divides covered products into equipment classes by the type of energy used or by capacity or other performance-related features that justify differing standards. In making a determination whether a performance-related feature justifies a different standard, DOE must consider such factors as the utility of the feature to the consumer and other factors DOE determines are appropriate. (42 U.S.C. 6295(q) and 6316(a)) DOE proposes dividing compressors based on the following factors, which are discussed in sections IV.A.1.a through IV.A.1.e:

• Compression principle,

• Lubricant presence,

• Cooling method,

• Motor speed type, and

• Motor phase count.

In the Framework Document, DOE requested stakeholder comment regarding whether and how compressors should be divided into separate classes. Stakeholder comments regarding equipment classes, the specific separation of equipment classes based on the listed factors, and the final list of proposed equipment classes are discussed further in the following sections. Generally, the notion of establishing separate equipment classes was supported by commenters.

a. Compression Principle

In response to the Framework Document, Saylor-Beall and Jenny compressors commented that rotary compressors are generally high-duty cycle equipment, while reciprocating compressors are generally low-duty cycle equipment. (Saylor-Beall, No. 0003 at p. 3; Jenny, No. 0005 at p. 4) As noted in section III.A, DOE considered standards for both reciprocating and rotary compressors as part of this rulemaking. DOE also proposes to divide these two compressor types into separate equipment classes. Rotary and reciprocating compressors have significantly different operating characteristics; as a result these equipment types are used in different applications and have different levels of attainable efficiency. Both rotary and reciprocating are considered to be positive displacement compressors, which act by compressing successive trapped volumes of air.

Reciprocating compressors compress air using the repeated linear motion of a moving member (

e.g.,

a piston) within a sealed compression chamber. Reciprocating compressors do not require a warm up period and can be operated using an on/off control scheme, making them best suited for intermittent and low duty cycle applications. This is because low cycles require frequent starting and stopping. Equipment which required warming up to operate properly would operate inefficiently, wear prematurely, or both. Reciprocating compressors use actuated valves to seal the compression chamber, which holds air leakage (a form of energy loss) to modest levels even when operating cold. Rotary compressors, by contrast, do not use valves but rely on carefully designed and manufactured rotor clearances, which are efficient after the rotor has heated and expanded to design specifications, in order to limit air leakage. Customers with low duty cycles may find additional utility, therefore, in reciprocating compressors. By contrast, reciprocating compressors, by nature of their reciprocating motion, produce more vibration and, therefore, may wear more quickly and, therefore, may offer reduced utility to customers with higher duty cycles and high cost of downtime.

Rotary compressors compress air progressively as it moves from the inlet point to the discharge point using the cyclical motion of one or several rotors. Rotary compressors may require a warm-up period to operate properly, and are therefore better suited for high duty cycle applications, in which equipment is less frequently cycled on

and off and, therefore, in which design operating temperatures may be maintained. Rotary compressors typically cannot be operated using an on/off control scheme; rather, they may be controlled by other methods such as load/unload, inlet flow modulation, and variable displacement drives. As mentioned in the previous paragraph, rotary compressors rely on reaching a certain operating temperature, or “warming up,” to allow mechanical parts to expand to reach the proper design clearances. Operating a rotary compressor in a low-duty, on/off manner, may cause the compressor to operate inefficiently, wear prematurely, or both. These control methods are discussed further in chapter 3 of the NOPR TSD.

Although reciprocating compressors typically have lower isentropic efficiencies than rotary compressors, reciprocating compressors excel in low duty cycle or intermittent applications and may consume less overall energy than a rotary compressor when deployed in such settings. Alternatively, to provide air for intermittent loads, a rotary compressor would be required to remain running in a modulated or unloaded condition, even at times of low or zero load. This is inherent in the scheme; a technology which cannot start and stop (either literally or because doing so would cause adverse consequences such as premature wear) must employ other capacity-reducing measures such as modulation or unloading to match supply to demand. Consequently, DOE concludes that dividing rotary and reciprocating compressors into separate equipment classes on the basis of suitability for different duty cycles is appropriate.

DOE requests comment on its proposal to establish separate equipment classes for rotary and reciprocating equipment, and on whether and why utility or performance differences exist between the two types of equipment. This is identified as Issue 6 in section VIII.E, “Issues on Which DOE Seeks Comment.”

b. Lubricant Presence

In response to the Framework Document, Atlas Copco commented that compressors can be divided into two separate groups, lubricated and lubricant-free.

(Atlas-Copco, No. 0008 at p. 3) DOE proposes to divide lubricated and lubricant-free into separate equipment classes. Compressors are manufactured in both lubricated and lubricant-free configurations. For the purposes of this rulemaking, DOE is proposing to define these lubrication types as follows:

“Lubricated compressor” means a compressor that introduces an auxiliary substance into the compression chamber during compression.

“Lubricant-free compressor” means a compressor that does not introduce any auxiliary substance into the compression chamber at any time during operation.

For the purposes of this rulemaking, DOE proposes to define “auxiliary substance” as follows:

“Auxiliary substance” means any substance deliberately introduced into a compression process to aid in compression of a gas by any of the following: Lubricating, sealing mechanical clearances, or absorbing heat.

DOE notes that lubricant-free compressors may still use lubricant within other portions of the compressor, as long as the lubricant does not enter the compression chamber at any point during operation. DOE also notes that, under the proposed definitions, compressors would be considered “lubricated” if an auxiliary substance of any sort were introduced into the compression chamber. This would include oil, and water, which is not typically described as a lubricant within the compressor industry.

DOE's analysis and research found that lubricated compressors are generally more efficient than lubricant-free compressors. In lubricated compressors, the lubricant is injected into the compression chamber to serve two primary purposes:

1. Sealing the compression chamber mechanical clearances and reduce air leakage by using the surface tension of the liquid to form a barrier to air escape, and

2. Cooling the compressed air during compression, increasing efficiency by bringing the compression process closer to a thermodynamic ideal.

Due to their inherently lower efficiencies and comparatively higher costs, lubricant-free compressors do not compete directly with lubricated compressors for general-purpose compressed air applications. However, certain applications with specific air purity requirements cannot use lubricated compressors due to the presence of residual lubricant that cannot be effectively removed from the output air using filtration. Examples of these applications include food processing equipment, clean-room manufacturing, and air for medical uses. Lubricant-free compressors are necessary to meet the air purity requirements of these applications. By contrast, a lubricant-free compressor could likely be used with no loss of utility in applications traditionally served by lubricated compressors. Because of their higher cost, however, they are typically deployed only when called for by customer utility requirements.

Lacking lubricant to aid in sealing clearances, lubricant-free compressors are usually manufactured with smaller clearances. Although this practice adds cost, it reduces some of the air leakage that result from a lack of lubrication. However, reducing clearances too far may result in increased friction and maintenance requirements. This limits how tight the clearances of lubricant-free compressors can be. As such, lubricant-free compressors still allow more leakage relative to lubricated compressors. This leakage reduces efficiency, because as the air is lost, so is the energy that was used to treat it. Further, lubricant-free compressors may require larger after-coolers than lubricated compressors. An after-cooler is used to cool the compressed air after compression and prior to discharge. The after-cooler causes package pressure losses and decreases in efficiency.

DOE notes that an ISO standard, 8573-1:2010,

exists and is used by industry to measure and describe the purity of air. Air is described as being “class zero” if it is determined to meet the most stringent air purity levels recognized by this standard. DOE is aware that some compressors that meet the proposed definition of lubricated in this document may also be able to meet the class zero standard of ISO 8573-1:2010. For example, the compressor may include an advanced lubricant filtration system to bring lubricant concentration below a certain threshold. Alternatively, the compressor may inject only water into the chamber, which may be removed with ordinary cooling and drying equipment.

See:

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

DOE requests comment on separating equipment classes by lubricant presence, and specifically on whether ISO 8573-1:2010 is suitable for characterizing compressors on that basis. DOE also requests comments on the proposed definitions for lubricated compressor, lubricant-free compressors, and auxiliary substance. This is identified as Issue 7 in section VIII.E, “Issues on Which DOE Seeks Comment.”

c. Cooling Method

DOE proposes to divide air-cooled and water-cooled rotary compressors into separate equipment classes. Due to considerable heat created during compression, compressors are normally packaged with cooling systems for both the air itself, and, if applicable, the lubricant. The cooling system may utilize either air or water to remove heat from the system. For the purposes of this rulemaking, DOE proposes to define the two cooling methods as follows:

“Air-cooled compressor” means a compressor that utilizes air to cool both the compressed air and, if present, any auxiliary substance used to facilitate compression.

“Water-cooled compressor” means a compressor that utilizes chilled water provided by an external system to cool both the compressed air and, if present, any auxiliary substance used to facilitate compression.

DOE's research and analysis of industry data indicates that water-cooled compressors are typically more efficient than air-cooled compressors, as measured by ISO 1217:2009.

Air-cooled compressors circulate ambient air through the heat exchangers to cool both the compressed air and lubricant. Air-cooled compressors usually require fans to circulate air through the heat exchangers; these fans increase the total package energy consumption, thus decreasing the total package efficiency.

Water-cooled compressors circulate chilled water from an external water supply through heat exchangers to cool both the compressed air and lubricant. The chilled water heat exchanger does not cause any additional energy consumption within the compressor package, as the cooling water is chilled and pumped from a remote location. However, water-cooled compressors can only be used in locations where chilled water is available, thus limiting the utility and applicability of water-cooled compressors. Conversely, air-cooled compressors require only air for cooling and can be used in locations where chilled water may not be available. Therefore, air-cooled compressors present a utility advantage to customers without access to a cooling water supply.

DOE notes that efficiency, as measured by the proposed test procedure NOPR, would reflect slightly different concepts for air- and water-cooled compressors. In both cases, a cooling medium is being actively circulated to remove heat from the unit and energy is being consumed to circulate the medium. But only in the case of air-cooled units is that energy consumption reflected in the efficiency metric. The consumption occurs remotely for water-cooled units. Without further analysis, it is difficult to assess which consumption may be greater overall. But this difference is what is measured by efficiency, in addition to the difference in end user utility already discussed, and offers a second justification for establishment of separate equipment classes.

DOE is not aware of any water-cooled reciprocating compressors currently available in the U.S. market. However, if such equipment does exist, or enters the market in the future, the data presented earlier in this section suggest that water-cooled compressors may be more efficient than similar air-cooled units. As a result, DOE proposes to consider both air- and water-cooled reciprocating compressors in a single equipment class and to base any energy conservation standards for both only on available air-cooled data. Based on comparison of air- and water-cooled rotary compressors, DOE concludes that it is technologically feasible for any water-cooled reciprocating compressor introduced to the market to meet an energy conservation standard set based on the current air-cooled reciprocating compressors market.

DOE requests comment on its proposal to establish separate equipment classes for air- and water-cooled equipment. DOE also requests comments on the proposed definitions for air- and water-cooled compressor. This is identified as Issue 8 in section VIII.E, “Issues on Which DOE Seeks Comment.”

d. Motor Speed

DOE's research indicates that electric motor-driven compressors can be further separated by the style of electric driver used in the package. Specifically, DOE found that compressors are sold with either a variable-speed driver, which can operate across a continuous range of driver speeds, or a fixed-speed driver, which can operate at only a single fixed-speed. In the test procedure NOPR, DOE proposed definitions for “fixed-speed compressor” and “variable-speed compressor.”

The term “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.

The term “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 found that variable-speed compressors are typically less efficient at full load than comparable fixed-speed compressors, partially due to efficiency losses within the variable-speed drive. Variable-speed compressors are typically intended for use in systems where air demand is expected to vary over the course of operation; this takes advantage of the unit's ability to operate more efficiently at part load. For this reason, variable-speed compressors are sometimes optimized for efficiency at part-load; this will typically result in full-load efficiencies lower than those of comparable fixed-speed units. Additionally, they may function as “trim” compressors in multi-unit installations. Trim compressors are normally the first ones to adjust their capacity output when overall system air demand changes. If the overall system air demand changes outside what the trim compressor is able to accommodate, additional compressors may be turned on and off according to which configuration would produce most efficient operation. By contrast, a “base load” compressor is expected to be operated either on or off a large fraction; this compressors is a poor candidate for variable-speed functionality, because of both the financial and full-load performance cost of adding that capability. Due to the difference in utility and attainable efficiency between fixed and variable-speed compressors, DOE proposes to separate these two compressor styles into separate equipment classes.

e. Motor Phase Count

DOE also proposes to divide single- and three-phase reciprocating compressors into separate equipment classes. Lower power reciprocating compressors, typically less than 10 hp, can be packaged with either single-phase or three-phase electric motors. Reciprocating compressors packaged with single-phase electric motors are typically less efficient than those packaged with three-phase electric motors due to the inherent lower efficiency of single-phase motors. Single-phase reciprocating compressors are generally used in applications with lower duty cycles and no access to three-phase power, such as tire inflation at a local service station, or oral surgery at a dental office. Three-phase reciprocating compressors typically see higher duty cycles and can only be used for applications in which three-phase power is available. An automotive body shop or very light industrial production

may have such compressors, but they would likely not be found as the primary air source for a high-volume industrial production application. Few residential applications have access to three-phase power. As a result, DOE concludes that single- and three-phase compressors offer different end user utility. Consequently, DOE proposes to divide reciprocating compressors packaged with single-phase and three-phase electric motors into separate equipment classes.

By contrast, DOE was able to find little data on single-phase rotary compressors, which appear to form a very small fraction of the market. As a result, DOE was not able to determine whether such equipment was able to meet the same performance levels as three-phase equipment. To avoid the risk of in advertently incentivizing the market to shift to single-phase rotary equipment (if separated or not included), DOE proposes in this NOPR not to separate rotary equipment classes by motor phase count. As such, each rotary equipment class encompasses both single- and three-phase equipment.

Based on interviews with manufacturers, DOE is aware that single-phase rotary equipment may be gaining popularity in European markets. If such equipment is being chosen to conserve energy, and if the adoption of increased standards may hinder the adoption or development of single-phase rotary equipment to save energy, DOE may consider establishing a separate standard for single-phase rotary equipment in the final rule.

DOE requests comment on the establishment of separate equipment classes, by motor phase count, for reciprocating equipment. This is identified as Issue 9 in section VIII.E, “Issues on Which DOE Seeks Comment.”

DOE also requests comment on the proposal to combine single- and three-phase rotary equipment in each rotary equipment class. This is identified as Issue 10 in section VIII.E, “Issues on Which DOE Seeks Comment.”

f. List of Proposed Equipment Classes

DOE's list of proposed equipment classes is provided in Table IV.1:

Table IV.1—List of DOE Proposed Compressor Equipment Classes

Compressor type

Lubrication type

Cooling method

Driver type

Motor phase

Equipment class designation

Rotary

Lubricated

Air-Cooled

Fixed-Speed

Variable-speed

Any

RP_FS_L_AC

RP_VS_L_AC

Water-Cooled

Fixed-Speed

Variable-speed

RP_FS_L_WC

RP_VS_L_WC

Lubricant-Free

Air-Cooled

Fixed-Speed

Variable-speed

RP_FS_LF_AC

RP_VS_LF_AC

Water-Cooled

Fixed-Speed

Variable-speed

RP_FS_LF_WC

RP_VS_LF_WC

Reciprocating

Lubricated

Air-Cooled or Water-Cooled

Fixed-Speed

Three-Phase

Single-Phase

R3_FS_L_XX

R1_FS_L_XX

Lubricant-Free

Three-Phase

Single-Phase

R3_FS_LF_XX

R1_FS_LF_XX

2. European Union Regulatory Action

The EU Ecodesign directive established a framework under which manufacturers of energy-using products are obliged to reduce the energy consumption and other negative environmental impacts occurring throughout the product life cycle.

Products are broken out in to different “Lots,” with compressors studied in Lot 31. In June 2014, the EU completed and published its final technical and economic study of Lot 31 compressors.

Source:

www.eceee.org/ecodesign/products/Compressors

For copies of the EU Lot 31 Final Report on Compressors, please go to:

www.regulations.gov/#!documentDetail;D=EERE-2013-BT-STD-0040-0031

As part of its study, the EU examined the entire compressors market to determine an appropriate scope of coverage for its energy conservation standards. The results of this study led the Commission of the European Communities to establish a working document proposing possible energy efficiency requirements for compressors. The EU draft regulation

proposed to cover the following compressor types:

For copies of the EU draft regulation:

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

• Oil-lubricated Rotary Air Compressor Packages with:

○ Rated output flow rate of between 5 to 1,280 liters per second,

When express in terms of inlet conditions, as is industry convention.

○ Three-phase electric motors,

○ Fixed or variable-speed drives, and

○ Full-load operating pressure of between 7 to 14 bar gauge.

• Oil-lubricated Reciprocating Air Compressor Packages with:

○ Rated output flow rate of between 2 to 64 liters per second,

○ Three-phase electric motors,

○ Fixed-speed drives, and

○ Full-load operating pressure of between 7 to 14 bar gauge.

The Lot 31 study used data collected from CAGI Performance Verification Program data sheets to determine the market distribution of compressor efficiency for rotary compressors and data collected from a confidential survey conducted of European manufacturers for reciprocating compressors.

The EU draft regulation proposed to separate the covered products into the following three equipment classes and to set a different standard level, based on package isentropic efficiency, for each class:

• Fixed-speed Rotary Standard Air Compressors—Standard level set as package isentropic efficiency at full-load operating conditions;

• Variable-speed Rotary Standard Air Compressors—Standard level set as a weighted average of package isentropic efficiency at 100-percent, 70-percent, and 40-percent of full-load operating conditions; and

• Piston Standard Air Compressors—Standard level set as package isentropic efficiency at full-load operating conditions.

a. Specific Suggested Requirements

The EU draft proposal suggests compliance beginning in 2018, and are increased in 2020 for certain compressor

types, as explain in Table IV.2 and Table IV.3:

Table IV.2—Draft First Tier Minimum Energy Efficiency Requirements for Standard Air Compressors From January 1, 2018

Standard air compressor type

Formula to calculate the

minimum

package isentropic efficiency, depending on the flow rate (V

) an proportional loss factor (d)

Proportional loss factor (d) to be used in the formula

Fixed-speed Rotary Standard Air Compressor

(−.0928 ln

) + 13.911 ln (V

) + 27.110) + (100−(−.0928 ln

) + 13.911 ln (V

) + 27.110) * d/100

−5

Variable-speed Rotary Standard Air Compressor

(−1.549 ln

) + 21.573 ln (V

) + 0.905) + (100−(−1.549 ln

) + 21.573 ln (V

) + 0.905) * d/100

−5

Piston Standard Air Compressor

(8.931 ln (V

) + 31.477) + (100−(8.931 ln (V

) + 31.477) * d/100

−5

Table IV.3—Draft Second Tier Minimum Energy Efficiency Requirements for Standard Air Compressors From January 1, 2020

Standard air compressor type

Formula to calculate the

minimum

package isentropic efficiency, depending on the flow rate (V

) an proportional loss factor (d)

Proportional loss factor (d) to be used in the formula

Fixed-speed Rotary Standard Air Compressor

(−0.928 ln

) + 13.911 ln (V

) + 27.110) + (100−(−0.928 ln

) + 13.911 ln (V

) + 27.110) * d/100

Variable-speed Rotary Standard Air Compressor

(−1.549 ln

) + 21.573 ln (V

) + 0.905) + (100−(−1.549 ln

) + 21.573 ln (V

) + 0.905) * d/100

Piston Standard Air Compressor

(8.931 ln (V

) + 31.477) + (100−(8.931 ln (V

) + 31.477) * d/100

b. Next Steps

The outcome of this draft regulation is undetermined, based on publicly available information. Based on the process outlined on the Ecodesign Web site, the document may need to be reviewed internally by the European Commission, sent to the World Trade Organization, submitted to the Regulatory Committee (composed of one representative from each EU Member State), and the finally sent to the European Parliament and Council for scrutiny.

As detailed here:

www.eceee.org/ecodesign/products/Ecodesign135lg.png

In parallel, the EU has announced

a second compressors study focusing on low-pressure and oil-free equipment. From the Web site,

the study was kicked off on 17 June, 2015, draft publications for “Task 1-4” were posted on 31 March, 2016, and additional draft publications and stakeholder meetings are planned for the future (with dates yet to be determined). Publication of the final report is scheduled for April 2017.

As viewed here:

http://www.eco-compressors.eu/documents.htm

As viewed here:

http://www.eco-compressors.eu/documents.htm

3. Technology Options

In the Framework Document, DOE identified several design options that could be used to improve compressor package efficiency including:

• Improved controls;

• Improved bare compressor

efficiency;

Frequently described in the compressor industry as an “air-end” or “airend.” For the purposes of this rulemaking, DOE considers the terms to be synonymous.

• Improved cooling fan efficiency;

• Improved part-load efficiency;

• Improved electric motors; and

• The use of multistage compressors.

In response to the Framework Document, the Joint Commenters recommended that DOE consider equipment that affect compressor efficiency, such as zero-loss condensate traps and waste heat recovery technologies. (Joint Comment, No. 0016 at p. 3-4) Further, DOE research indicated that even though all of the options listed in the Framework Document were valid paths to higher efficiency, in practice, they were not considered independently by manufacturers but, rather, deployed as needed depending on the specifics of the compressor design and ultimate desired efficiency level. As for this document, DOE is altering its proposed categorization of options to improve efficiency. This is because the options listed above are in some cases able to be deployed independently (

e.g.,

cooling fan efficiency) and in other cases require coordination (

e.g.,

using a more efficient motor). Instead of a bottom-up approach, wherein DOE could attempt to assign a characteristic improvement, DOE's proposed approach “top-down,” where the primary consideration is the overall package efficiency and exploration is of the overall cost required to achieve certain efficiencies. Instead of independent options, DOE will generally consider all efficiency improvement to come from a “package redesign” which could include any, or all of the listed options from the Framework Document. This package redesign can be thought of as including three broad categories of improvements:

• Multi-staging;

• Air-end Improvement; and

• Auxiliary Component Improvement.

These package redesign options are addressed separately in the sections that follow.

a. Multi-Staging

Compressors ingest air at ambient conditions and compress it to a higher pressure required by the specific application. Compressors can perform this compression in one or multiple stages, where a stage corresponds to a single air-end and offers the opportunity for heat removal before the next stage. Units that compress the air from ambient to the specified design pressure of the compressor in one step are referred to as single-stage compressors, while units that use multiple steps are referred to as multistage compressors.

The act of compression generates inherent heat in a gas. If the process occurs quickly enough to limit the transfer of that heat to the environment, the compression is known as “adiabatic.” By contrast, compression may be performed slowly such that heat flows from the gas at the same rate it is generated, and such that the temperature of the gas never exceeds that of the environment. This process is called “isothermal.” DOE notes that a hotter gas is conceptually “harder” to compress; the compressor must overcome the heat energy present in the gas in order to continue the compression process. As a result, compression to a given volume requires less work if performed isothermally. “Real” (

i.e.,

not idealized in any respect) compressors are neither adiabatic nor isothermal, and dissipate some portion of compressive heat during the process. If a compressor is able to dissipate more heat, the resulting act of compression becomes easier and the compressor requires less input energy.

Multi-stage compressors are specifically designed to take advantage of this principle and split the compression process into two or more stages (each performed in a single air-end) to allow heat removal between the stages using a heat-exchange device sometimes called an “intercooler.” The more stages used, the closer the compressor behavior comes to the isothermal ideal. Eventually, however, the benefits to adding further stages diminish; gains from each marginal stage is countered by the inherent inefficiencies of using smaller compressor units. Depending on the specific pressure involved, the optimal number of stages may vary widely. Most standard industrial air applications, however, do not use more than two stages.

Lubricant-free compressors typically realize greater efficiency gains than lubricated compressors, as the lubricant used, usually oil, acts as a coolant during the compression process, thus reducing the benefit of intercooling between stages.

b. Air-End Improvement

The efficiency of any given air-end depends upon a number of factors, including:

• Rated compressor output capacity;

• Compression chamber geometry;

• Operating speed;

• Surface finish;

• Manufacturing precision; and

• Designed equipment tolerances.

Each individual air-end has a best efficiency operating point based upon the characteristics listed. However, because air-ends can operate at multiple flow rates, manufacturers commonly utilize a given air-end in multiple compressor packages to reduce overall costs. This results in air-ends operating outside of the best efficiency point. Using one air-end in multiple compressor packages reduces the total number of air-ends a manufacturer needs to provide across the entire market, reducing costs at the price of reduced efficiency for those packages operating outside of the best efficiency point for the air-end. However, a manufacturer could redesign and optimize air-ends for any given flow rate and discharge pressure, increasing the overall efficiency of the compressor package.

Manufacturers can use two viable design pathways to increase compressor efficiency via air-end improvement. The first is to enhance a given air-end design's properties that affect efficiency, which could include manufacturing precision, surface finish, mechanical design clearances, and overall aerodynamic efficiency. The second is to more appropriately match air-ends and applications by building an overall larger number of air-end designs. As a result, a given air-end will be used less frequently in applications requiring it to operate further from its optimal operating point. These two practices may be employed independently or jointly; the option that is prioritized will depend on the specifics of a manufacturer's equipment line and the ultimate efficiency level desired.

c. Auxiliary Component Improvement

As discussed in the previous section, compressor manufacturers normally use one air-end in multiple compressor packages that are designed to operate at different discharge pressures and flow rates. Each compressor package consists of multiple design features that affect package efficiency, including valves, piping system, motor, capacity controls, fans, fan motors, filtration, drains, and driers. This equipment, for example, may control the flow of air, moisture, or oil, or the temperature and humidity of output air, or regulate temperature and operation, Compressor manufacturers do not normally provide the option to replace any individual part of a compressor package to increase efficiency, as each feature also has a direct effect on compressor performance. However, improving the operating characteristics of any of these “auxiliary” parts may offer a chance to improve the overall efficiency of the compressor package.

For example, package isentropic efficiency can be increased by reducing the internal pressure drop of the package using improved valves and pipe systems, or by improving the efficiency of (1) both the drive and fan motors (if present), (2) the fan, itself, (3) condensate drains, (4) both air and lubricant filters (if present), (4) air driers, and (5) controls. The improvement must be considered relative to a starting point, however. Even if the modifications could be deployed independently of each other, and not all can, the spread of efficiencies available in the market likely already reflects the more cost effective choice for improving efficiency at any given point. Perhaps one manufacturer, by virtue of features of its product lines, finds that reaching a given efficiency level in a particular equipment class, is most cost effectively done by improving Technology X. Another may find that it is more cost effective to improve Technology Y. And both could be correct, because each may have had a different starting point. Adding to this difficulty in ascertaining exactly when a given technology should be deployed (as with a bottom-up technology option approach) is a manufacturing reality—it is not cost effective to offer an infinite number of combinations and equipment sizes. Perhaps a compressor of output level between two others would most optimally use a fan sized specifically for that compressor. Because it is not cost effective for that compressor's manufacturer to stock another fan size, however, the compressor ends up sub-optimally using a fan either slightly too large or slightly too small, at some small cost to efficiency. So, less may be learned by scrutinizing the design choices of a specific model that is learned by considering the overall spread of costs and efficiencies available in the market at-large.

DOE notes that, because the compressor packages function as an ensemble of complementary parts, changing one part often calls for

changing others. A special case may come with more efficient electric motors. Compressors normally use induction motors, which generally vary operating speed as efficiency is improved. Using a more efficient (but otherwise identical) induction motor without considering the rest of the compressor design could be counterproductive if the gains in motor efficiency were more than offset by subsequent loss in performance of the air-end and other parts. DOE's proposal assumes that the best-performing compressors on the market are built using the most-efficient available electric motors that are suited to the task. However, it could not confirm instances of a manufacturer using “super premium” or “IE4” induction motors, which appear to only recently have been made available commercially.

These terms (“super premium” and “IE4”) have been used (in the U.S. and Europe, respectively) to describe the motor industry's “next tier” of efficiency. Possible reasons for this include the motors not being suitable for use in compressors, manufacturers are still exploring the relatively new motors and have not yet introduced equipment redesigned to make use of them, or that manufacturers are already, in fact, using them in the most efficient compressor offerings.

One manufacturer, for example, describes its IE4 offerings here:

http://www.regulations.gov/#!documentDetail;D=EERE-2013-BT-STD-0040-0033

As an example of the influence of auxiliary componentry, the European Union Draft Standard offers a list of equipment with which the unit must be tested in order to certify compliance with standards.

It does not provide definitions for the terms, but as an example, for fixed-speed rotary compressors, required equipment includes:

See page 12 of

http://www.regulations.gov/#!documentDetail;D=EERE-2013-BT-STD-0040-0032

1. Electric motor

2. Cooling fan

3. Compression element

4. Transmission (Belt, Gear, Coupling . . .), (if applicable)

5. Inlet filter

6. Inlet valve

7. Minimum pressure check valve/backflow check valve

8. Oil separator

9. Air piping

10. Oil piping

11. Oil pump (if applicable)

12. Oil filter

13. Oil cooler

14. Thermostatic valve

15. Electrical switchgear

16. Compressor after-cooler

17. Compressor control device (pressure switch, pressure transducer, etc.)

The list implies that each component affects efficiency, but does not say whether improvement of any particular component is possible. Nonetheless, it is illustrative of the set of componentry that needs to function harmoniously in order for the package to perform well.

DOE also requests comment specifically on IE4 or “super premium” electric motors, their suitability for compressors, and on any efforts to incorporate them into newly developed equipment. This is identified as Issue 11 in section VIII.E, “Issues on Which DOE Seeks Comment.”

B. Screening Analysis

DOE generally uses the following four screening criteria to determine which technology options are suitable for further consideration in an energy conservation standards rulemaking:

1. Technological feasibility.

Technologies that are not incorporated in commercial products or in working prototypes will not be considered further.

2. Practicability to manufacture, install, and service.

If it is determined that mass production and reliable installation and servicing of a technology in commercial products could not be achieved on the scale necessary to serve the relevant market at the time of the projected compliance date of the standard, then that technology will not be considered further.

3. Impacts on product utility or product availability.

If it is determined that a technology would have significant adverse impact on the utility of the product to significant subgroups of consumers or would result in the unavailability of any covered product type with performance characteristics (including reliability), features, sizes, capacities, and volumes that are substantially the same as products generally available in the United States at the time, it will not be considered further.

4. Adverse impacts on health or safety.

If it is determined that a technology would have significant adverse impacts on health or safety, it will not be considered further.

See 10 CFR part 430, subpart C, appendix A, 4(a)(4) and 5(b).

Technologies that pass through the screening analysis are referred to as “design options” in the engineering analysis. The screening analysis and engineering analysis are discussed in detail, respectively, in Chapters 4 and 5 of the TSD.

The subsequent sections include comments from interested parties pertinent to the screening criteria, DOE's evaluation of each technology option against the screening analysis criteria, and whether DOE screened out a particular technology option based on the above criteria.

1. Screened-Out Technologies

Of the identified technology options, DOE was not able to identify any that would fail the screening criteria. The cost of additional engineering resources is considered in the Manufacturer Impact Analysis of section IV.J. DOE seeks comment on whether sufficient resources would be available such that criterion 2 of the screening analysis is satisfied. This is identified as Issue 12 in section VIII.E, “Issues on Which DOE Seeks Comment.”

2. Remaining Technologies

After reviewing each technology, DOE tentatively concludes that all of the identified technologies listed in section IV.A.3 met all four screening criteria to be examined further as design options in DOE's NOPR analysis. In summary, DOE did not screen out the following technology options:

• Multi-staging

• Air-end Improvement

• Auxiliary Component Improvement

DOE determined that these technology options are technologically feasible because they are being used or have previously been used in commercially-available products or working prototypes. DOE also finds that all of the remaining technology options meet the other screening criteria (

i.e.,

practicable to manufacture, install, and service and do not result in adverse impacts on consumer utility, equipment availability, health, or safety). For additional details, see chapter 4 of the NOPR TSD.

C. Engineering Analysis

In the engineering analysis, DOE describes the relationship between manufacturer selling price (MSP) to improved compressor package isentropic efficiency. This relationship serves as the basis for cost-benefit calculations for individual end users, manufacturers, and the Nation. DOE typically structures the engineering analysis using one of three approaches: (1) Design-option; (2) efficiency level; or (3) reverse-engineering (or cost assessment). The design-option approach involves adding the estimated cost and associated efficiency of various efficiency-improving design changes to the baseline equipment to model different levels of efficiency. The

efficiency level approach uses estimates of costs and efficiencies of equipment available on the market at distinct efficiency levels to develop the cost-efficiency relationship. The reverse-engineering approach involves testing equipment for efficiency and determining cost from a detailed bill of materials (BOM) derived from reverse-engineering representative equipment. The efficiency ranges from that of the least-efficient compressor sold today (

i.e.,

the baseline) to the maximum technologically feasible efficiency level. At each efficiency level examined, DOE determines the MSP; this relationship is referred to as a cost-efficiency curve.

DOE conducted the engineering analysis for this rulemaking using an efficiency level approach. The decision to use this approach was made due to several factors, including the wide variety of equipment sizes analyzed, the availability of reliable performance data, the availability of a comparable European Union study, and the nature of the design options available for the equipment.

1. Summary of Significant Data Sources

For the engineering analysis, DOE utilized four principal data sources: (1) A database of c

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