Energy Conservation Program: Test Procedure for Circulator Pumps

Federal RegisterDec 20, 2021

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2016-BT-TP-0033]

RIN 1904-AD77

Energy Conservation Program: Test Procedure for Circulator Pumps

AGENCY:

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

ACTION:

Notice of proposed rulemaking and request for comment.

SUMMARY:

The U.S. Department of Energy (“DOE”) proposes to establish definitions, a test procedure, sampling and rating requirements, and enforcement provisions for circulator pumps. Currently, circulator pumps are not subject to DOE test procedures or energy conservation standards. DOE proposes a test procedure for measuring the circulator energy index for circulator pumps. The proposed test method references the relevant industry test standard. The proposed definitions and test procedures are based on the recommendations of the Circulator Pump Working Group, which was established under the Appliance Standards Rulemaking Federal Advisory Committee. DOE is seeking comment from interested parties on the proposal.

DATES:

DOE will accept comments, data, and information regarding this proposal no later than February 18, 2022. See section V “Public Participation,” for details. DOE will hold a webinar on Wednesday, February 2, 2022, from 12:30 p.m. to 3:30 p.m. See section V, “Public Participation,” for webinar registration information, participant instructions, and information about the capabilities available to webinar participants. If no participants register for the webinar, it will be cancelled.

ADDRESSES:

Interested persons are encouraged to submit comments using the Federal eRulemaking Portal at

www.regulations.gov.

Follow the instructions for submitting comments. Alternatively, interested persons may submit comments, identified by docket number EERE-2016-BT-TP-0033, by any of the following methods:

Federal eRulemaking Portal: www.regulations.gov.

Follow the instructions for submitting comments.

Email:

CirculatorPumps2016TP0033@ee.doe.gov.

Include docket number EERE-2016-BT-TP-0033 in the subject line of the message.

No telefacsimiles (“faxes”) will be accepted. For detailed instructions on submitting comments and additional information on this process, see section V of this document.

Although DOE has routinely accepted public comment submissions through a variety of mechanisms, including the Federal eRulemaking Portal, email, postal mail, or hand delivery/courier, the Department has found it necessary to make temporary modifications to the comment submission process in light of the ongoing coronavirus 2019 (“COVID-19”) pandemic. DOE is currently suspending receipt of public comments via postal mail and hand delivery/courier. If a commenter finds that this change poses an undue hardship, please contact Appliance Standards Program staff at (202) 586-1445 to discuss the need for alternative arrangements. Once the COVID-19 pandemic health emergency is resolved, DOE anticipates resuming all of its regular options for public comment submission, including postal mail and hand delivery/courier.

Docket:

The docket, which includes

Federal Register

notices, public meeting attendee lists and transcripts (if a public meeting is held), comments, and other supporting documents/materials, is available for review at

www.regulations.gov.

All documents in the docket are listed in the

www.regulations.gov

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

The docket web page can be found at

www.regulations.gov/docket/EERE-2016-BT-STD-0004.

The docket web page contains instructions on how to access all documents, including public comments, in the docket. See section V for information on how to submit comments through

www.regulations.gov.

FOR FURTHER INFORMATION CONTACT:

Mr. Jeremy Dommu, U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies Office, EE-2J, 1000 Independence Avenue SW, Washington, DC, 20585-0121. Telephone: (202) 586-9870. Email:

ApplianceStandardsQuestions@ee.doe.gov.

Ms. Amelia Whiting, U.S. Department of Energy, Office of the General Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC, 20585-0121. Telephone: 202-586-2588. Email:

Amelia.Whiting@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 the Appliance and Equipment Standards Program staff at (202) 287-1445 or by email:

ApplianceStandardsQuestions@ee.doe.gov.

SUPPLEMENTARY INFORMATION:

DOE proposes to incorporate by reference the following industry standard into part 431:

Hydraulic Institute (“HI”) 40.6-2021, (“HI 40.6-2021”) “Methods for Rotodynamic Pump Efficiency Testing”.

Copies of HI 40.6-2021 can be obtained from: the Hydraulic Institute at 6 Campus Drive, First Floor North, Parsippany, NJ 07054-4406, (973) 267-9700, or by visiting:

www.Pumps.org.

For a further discussion of this standard, see section IV.M. of this document.

Table of Contents

I. Authority and Background

A. Authority

B. Background

II. Synopsis of the Notice of Proposed Rulemaking

III. Discussion

A. General Comments

B. Scope and Definitions

1. CPWG Recommendations

2. Definition of Circulator Pump

3. Definition of Circulator Pump Varieties

4. Definition of Circulator-Less-Volute and Header Pump

5. Definition of On-Demand Circulator Pumps

6. Applicability of Test Procedure Based on Pump Configuration

7. Basic Model

C. Rating Metric

D. Test Methods for Different Circulator Pump Categories and Control Varieties

1. Definitions Related to Circulator Pump Control Varieties

2. Reference System Curve

3. Pressure Control

4. Temperature Control

5. Manual Speed Control

6. External Input Signal Control

7. No Controls

E. Determination of Circulator Pump Performance

1. Incorporation by Reference of HI 40.6-2021

2. Exceptions, Modifications and Additions to HI 40.6-2021

a. Applicability and Clarification of Certain Sections of HI 40.6-2021

b. Testing Twin Head Circulator Pumps and Circulators-Less-Volute

c. Determination of Circulator Pump Driver Power Input at Specified Flow Rates

d. Calculation and Rounding Modifications and Additions

3. Rated Hydraulic Horsepower

F. Sampling Plan and Enforcement Provisions for Circulator Pumps

1. Sampling Plan

2. Enforcement Provisions

G. Representations of Energy Use and Energy Efficiency

H. Test Procedure Costs and Harmonization

1. Test Procedure Costs and Impact

a. Estimated Capital Costs for Testing Circulator Pumps

b. Between Estimated Labor Costs for Testing Circulator Pumps

2. Harmonization With Industry Standards

I. Compliance Date

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866

B. Review Under the Regulatory Flexibility Act

1. Description of Why Action Is Being Considered

2. Objective of, and Legal Basis for, Rule

3. Description and Estimate of Small Entities Regulated

4. Description and Estimate of Compliance Requirements

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

6. Significant Alternatives to the Rule

C. Review Under the Paperwork Reduction Act of 1995

D. Review Under the National Environmental Policy Act of 1969

E. Review Under Executive Order 13132

F. Review Under Executive Order 12988

G. Review Under the Unfunded Mandates Reform Act of 1995

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

I. Review Under Executive Order 12630

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

K. Review Under Executive Order 13211

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

M. Materials Incorporated by Reference

V. Public Participation

A. Participation in the Webinar

B. Procedure for Submitting Prepared General Statements for Distribution

C. Conduct of the Webinar

D. Submission of Comments

E. Issues on Which DOE Seeks Comment

I. Authority and Background

Pumps are included in the list of “covered equipment” for which DOE is authorized to establish test procedures and energy conservation standards. (42 U.S.C. 6311(1)(A)) Circulator pumps, which are the subject of this notice of proposed rulemaking (“NOPR”), are a category of pumps. Circulator pumps generally are designed to circulate water in commercial and residential applications. Circulator pumps do not include dedicated-purpose pool pumps, for which test procedures and energy conservation standards are established in title 10 of the Code of Federal Regulations (“CFR”) part 431 subpart Y. Currently, circulator pumps are not subject to DOE test procedures or energy conservation standards. The following sections discuss DOE's authority to establish test procedures for circulator pumps and relevant background information regarding DOE's consideration of test procedures for this equipment.

A. Authority

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

authorizes DOE to regulate the energy efficiency of a number of consumer products and certain industrial equipment. (42 U.S.C. 6291-6317) Title III, Part C

of EPCA, added by Public Law 95-619, Title IV, section 441(a) (42 U.S.C. 6311-6317 as codified), established the Energy Conservation Program for Certain Industrial Equipment, which sets forth a variety of provisions designed to improve energy efficiency. This equipment includes pumps, the subject of this document. (42 U.S.C. 6311(1)(A))

All references to EPCA in this document refer to the statute as amended through the Energy Act of 2020, Public Law 116-260 (Dec. 27, 2020).

For editorial reasons, upon codification in the U.S. Code, Part C was redesignated Part A-1.

The energy conservation program under EPCA consists essentially of four parts: (1) Testing, (2) labeling, (3) Federal energy conservation standards, and (4) certification and enforcement procedures. Relevant provisions of EPCA include definitions (42 U.S.C. 6311), test procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315), energy conservation standards (42 U.S.C. 6313), and the authority to require information and reports from manufacturers (42 U.S.C. 6316).

The Federal testing requirements consist of test procedures that manufacturers of covered equipment must use as the basis for: (1) Certifying to DOE that their equipment complies with the applicable energy conservation standards adopted pursuant to EPCA (42 U.S.C. 6316(a); 42 U.S.C. 6295(s)), and (2) making representations about the efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE must use these test procedures to determine whether the equipment complies with relevant standards promulgated under EPCA. (42 U.S.C. 6316(a); 42 U.S.C. 6295(s))

Federal energy efficiency requirements for covered equipment established under EPCA generally supersede State laws and regulations concerning energy conservation testing, labeling, and standards. (42 U.S.C. 6316(a) and 42 U.S.C. 6316(b); 42 U.S.C. 6297) DOE may, however, grant waivers of Federal preemption for particular State laws or regulations, in accordance with the procedures and other provisions of EPCA. (42 U.S.C. 6316(b)(2)(D))

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

Before prescribing any final test procedures, the Secretary must publish proposed test procedures in the

Federal Register

and afford interested persons an opportunity (of not less than 45 days' duration) to present oral and written data, views, and arguments on the proposed test procedures. (42 U.S.C. 6314(b))

DOE is publishing this NOPR in accordance with the statutory authority in EPCA.

B. Background

As stated, EPCA includes “pumps” among the industrial equipment listed as “covered equipment” for the purpose of Part A-1, although EPCA does not define the term “pump.” (42 U.S.C. 6311(1)(A)) In a final rule published January 25, 2016, DOE established a definition for “pump,” associated definitions, and test procedures for certain pumps. 81 FR 4086 (“January 2016 TP final rule”). “Pump” is defined as equipment designed to move liquids (which may include entrained gases, free solids, and totally dissolved solids) by physical or mechanical action and includes a bare pump and, if included by the manufacturer at the time of sale, mechanical equipment, driver, and controls. 10 CFR 431.462. Circulator pumps fall within the scope of this definition.

While DOE has defined “pump” broadly, the test procedure established in the January 2016 TP final rule is applicable only to certain categories of clean water pumps,

specifically those that are end suction close-coupled; end suction frame mounted/own bearings; in-line (“IL”); radially split, multi-stage, vertical, in-line diffuser casing; and submersible turbine (“ST”) pumps with the following characteristics:

A “clean water pump” is a pump that is designed for use in pumping water with a maximum non-absorbent free solid content of 0.016 pounds per cubic foot, and with a maximum dissolved solid content of 3.1 pounds per cubic foot, provided that the total gas content of the water does not exceed the saturation volume, and disregarding any additives necessary to prevent the water from freezing at a minimum of 14 °F. 10 CFR 431.462.

• 25 gallons per minute (“gpm”) and greater (at best efficiency point (“BEP”) at full impeller diameter);

• 459 feet of head maximum (at BEP at full impeller diameter and the number of stages specified for testing);

• design temperature range from 14 to 248 °F;

• designed to operate with either (1) a 2- or 4-pole induction motor, or (2) a non-induction motor with a speed of rotation operating range that includes speeds of rotation between 2,880 and 4,320 revolutions per minute (“rpm”) and/or 1,440 and 2,160 rpm, and in either case, the driver and impeller must rotate at the same speed;

• 6-inch or smaller bowl diameter for ST pumps;

• A specific speed less than or equal to 5,000 for ESCC and ESFM pumps;

• Except for: Fire pumps, self-priming pumps, prime-assist pumps, magnet driven pumps, pumps designed to be used in a nuclear facility subject to 10 CFR part 50, “Domestic Licensing of Production and Utilization Facilities”; and pumps meeting the design and construction requirements set forth in any relevant military specifications.

E.g.

, MIL-P-17639F, “Pumps, Centrifugal, Miscellaneous Service, Naval Shipboard Use” (as amended); MIL-P-17881D, “Pumps, Centrifugal, Boiler Feed, (Multi-Stage)” (as amended); MIL-P-17840C, “Pumps, Centrifugal, Close-Coupled, Navy Standard (For Surface Ship Application)” (as amended); MIL-P-18682D, “Pump, Centrifugal, Main Condenser Circulating, Naval Shipboard” (as amended); and MIL-P-18472G, “Pumps, Centrifugal, Condensate, Feed Booster, Waste Heat Boiler, And Distilling Plant” (as amended). Military specifications and standards are available at

http://everyspec.com/MIL-SPECS.

10 CFR 431.464(a)(1). The pump categories subject to the current test procedures are referred to as “general pumps” in this document. As stated, circulator pumps are not general pumps.

DOE also published a final rule establishing energy conservation standards applicable to certain classes of general pumps. 81 FR 4368 (Jan. 26, 2016) (“January 2016 ECS final rule”);

see also

10 CFR 431.462. DOE recognized circulator pumps as a category of pumps, but DOE did not define “circulator pump”. 81 FR 4086, 4097.

In this NOPR, DOE is proposing a definition of circulator pump, associated definitions for categories of circulator pumps, as well as related definitions for control varieties of circulator pumps (see sections III.B.2, III.B.4, III.B.5 and III.D.1 of this NOPR). These definitions are necessary to establish the scope of applicability of the proposed circulator pump test procedure. The scope of the proposed test procedure is discussed in section III.B.6 of this document.

1. CPWG Recommendations

As discussed in the May 2021 RFI, the September 2016 Circulator Pump Recommendations addressed the scope of a circulator pumps rulemaking. Specifically, the CPWG recommended that the scope of a circulator pumps test procedure and energy conservation standards cover clean water pumps (as defined at 10 CFR 431.462) distributed in commerce with or without a volute

and that are one of the following categories: Wet rotor circulator pumps, dry rotor close-coupled circulator pumps, and dry rotor mechanically-coupled circulator pumps. The CPWG also recommended that the scope exclude submersible pumps and header pumps. 86 FR 24516, 24520; (Docket No. EERE-2016-BT-STD-0004, No. 58, Recommendations #1A, 2A and 2B at p. 1-2) The CPWG also recommended the following definitions relevant to scope:

Volutes are also sometimes referred to as a “housing” or “casing.”

Wet rotor circulator pump

means a single stage, rotodynamic, close-coupled, wet rotor pump. Examples include, but are not limited to, pumps generally referred to in industry as CP1.

Dry rotor, two-piece circulator pump

means a single stage, rotodynamic, single-axis flow, close-coupled, dry rotor pump that:

(1) Has a hydraulic power less than or equal to five horsepower at best efficiency point at full impeller diameter,

(2) is distributed in commerce with a horizontal motor, and

(3) discharges the pumped liquid through a volute in a plane perpendicular to the shaft. Examples include, but are not limited to, pumps generally referred to in industry as CP2.

Dry rotor, three-piece circulator pump

means a single stage, rotodynamic, single-axis flow, mechanically-coupled, dry rotor pump that:

(1) Has a hydraulic power less than or equal to five horsepower at best efficiency point at full impeller diameter,

(2) is distributed in commerce with a horizontal motor, and

(3) discharges the pumped liquid through a volute in a plane perpendicular to the shaft. Examples include, but are not limited to, pumps generally referred to in industry as CP3.

Horizontal motor

means a motor that requires the motor shaft to be in a horizontal position to function as designed under typical operating conditions, as specified in manufacturer literature.

Submersible pump

means a pump that is designed to be operated with the motor and bare pump fully submerged in the pumped liquid.

Header pump

means a pump that consists of a circulator-less-volute intended to be installed in an original equipment manufacturer (“OEM”) piece of equipment that serves as the volute. (Docket No. EERE-2016-BT-STD-0004, No. 58, Recommendations #2B, 3A, and 3B at p. 2-3); 86 FR 24516, 24520.

DOE notes that generally these definitions rely on terms previously defined in the January 2016 TP final rule, including “close-coupled pump,” “mechanically-coupled pump,” “dry rotor pump,” “single axis flow pump,” and “rotodynamic pump.” 81 FR 4086, 4146-4147; 10 CFR 431.462. In addition, the recommended definition for submersible pump is the same as that already defined in a 2017 test procedure final rule for dedicated-purpose pool pumps (“August 2017 DPPP TP final rule”). 82 FR 36858, 36922 (August 7, 2017);10 CFR 431.462.

DOE discusses the proposed definitions of wet rotor circulator pump; dry rotor, two-piece circulator pump; dry rotor, three-piece circulator pump; and horizontal motor in section III.B.3, header pump in section III.B.4, and submersible pump in section III.B.6 of this NOPR.

2. Definition of Circulator Pump

Circulator pumps are a subset of small, IL pumps that are designed to provide a small amount of head to overcome pipe friction losses in a water circulation system for hydronic heating or cooling and potable hot water recirculation. During the CPWG meetings, the CPWG discussed the applications and utilities that circulator pumps serve and the distinctions in the designs of circulator pump varieties.

In defining circulator pump, the CPWG reviewed the descriptions established in the standard American National Standards Institute (“ANSI”)/HI 1.1-1.2-2014 standard (“ANSI/HI 1.1-1.2-2014”), “Rotodynamic Centrifugal Pumps for Nomenclature and Definitions.” (Docket No. EERE-2016-BT-STD-0004, No. 64 at pp.41-43) Section 1.1.3.3.5 of ANSI/HI 1.1-1.2-2014 characterizes circulator pumps based on the following four unique features: (1) Rotating assemblies that must be horizontally mounted; (2) being fully supported in-line by the system piping; (3) utilizing special-purpose motors unique to this pump type; and (4) having a motor shaft power that does not exceed 3.75 kilowatts (“kW”) (5 horsepower (“hp”)).

Sections 1.1.3.3.5.1-2 of ANSI/HI 1.1-1.2-2014 provide definitions for three unique types of circulator pumps. These three unique circulator pump varieties are based on two main characteristics: (1) Whether the motor is isolated from or immersed in the pumped liquid, and (2) how the impeller and motor are connected. Regarding the first characteristic, a circulator pump may be wet rotor, meaning that the motor rotor is immersed in the pumped liquid during operation; or dry rotor, meaning that the pump is not immersed in the pumped liquid. Dry rotor pumps typically include a mechanical seal that isolates the motor rotor from the pumped liquid.

The second characteristic, which pertains to how the impeller and motor are connected, further subdivides wet rotor and dry rotor circulator pumps into close-coupled or mechanically-coupled varieties. A close-coupled pump has a motor and impeller that share a common shaft, while a mechanically-coupled pump features an impeller that has its own shaft that is connected by mechanical means to the motor shaft.

Based on these differentiating features, Sections 1.1.3.3.5.1-2 of ANSI/HI 1.1-1.2-2014 defines the following circulator pump varieties:

• Close-coupled circulator pumps (CP1 and CP2)—Close-coupled circulator pumps may have driver elements that are immersed in the pumped fluid (CP1) or isolated by a mechanical seal (CP2). The rotating assembly shares a common shaft; the bearing(s) of the rotating assembly absorb all pump hydraulic loads (axial and radial). The driver is aligned and assembled directly to the pump unit with machined fits.

• Flexibly-coupled circulator pumps (CP3)—In flexibly-coupledcirculator pumps, the pump has a shaft supported by its own bearings that absorb all pump hydraulic loads (axial and radial). The driver is aligned and assembled directly to the pump unit with machined fits, typically with a resilient mount to damped vibration. The pump and driver shafts are flexibly coupled via flexible element drive couplings.

“Flexibly-coupled” is a more specific use of the term “mechanically-coupled”. Consistent with 10 CFR 431.462 and CPWG recommendations, DOE uses the term “mechanically-coupled” throughout the remainder of this notice.

Consistent with the ANSI/HI 1.1-1.2-2014 classification, the CPWG discussed defining three varieties of circulator pumps: (1) Wet rotor circulator pumps, (2) dry rotor close-coupled circulator pumps, and (3) dry rotor mechanically-coupled circulator pumps. (Docket No. EERE-2016-BT-STD-0004, No. 64 at pp.41-43)

The specific definitions for wet rotor circulator pumps and dry rotor circulator pumps are discussed in the following sections.

The CPWG also discussed the applicability of the recommended test procedure and standards to circulator pumps distributed in commerce without a volute. As discussed in more detail in section III.B.4, the CPWG discussed how some circulator pumps are distributed in commerce without a volute, either as a replacement for an existing circulator pump that has failed or to be newly installed with a paired volute in the field. (Docket No. EERE-2016-BT-STD-0004, No. 74 at pp. 383-407). In section III.E.2.b, DOE proposes specific instructions regarding how to test a “circulator-less-volute.”

To specify that the recommended circulator pump test procedure and standards are intended to apply to circulator pumps, with or without a volute, the CPWG recommended adding such language to the recommended circulator pump definition. (Docket No. EERE-2016-BT-STD-0004, No. 66 at pp. 156-164). The CPWG also recommended to define circulator pump as being comprised of the following pump categories distributed in commerce with or without a volute: Wet rotor circulator pumps, dry rotor close-coupled circulator pumps, and dry rotor mechanically-coupled circulator pumps. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #1A at p. 1)

DOE notes that the terminology in the CPWG recommended definition for circulator pump does not match the terminology in the CPWG recommended definitions for the circulator pump categories. Specifically, the recommended circulator pump definition includes “dry rotor close-coupled circulator pumps” and “dry rotor mechanically-coupled circulator pumps,” while the recommended defined terms are “dry rotor, two-piece circulator pump” and “dry rotor, three-piece circulator pumps.” (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #1A, 3A, and 3B at pp. 1-3) Those defined terms reference close-coupling and mechanical-coupling, respectively. DOE notes that HI 41.5-2021 defines circulator pump in section 41.5.1.5.1 as a wet rotor circulator pump (CP1); a dry rotor, two-piece circulator pump (CP2); or a dry rotor three-piece circulator pump (CP3). Based on their use in the industry test procedure, DOE understands that “two-piece” and “three-piece” are the preferred industry terms over the terms “close-coupled” and “mechanically-

coupled,” and has proposed the use of the industry terms.

DOE is proposing a definition of circulator pump at 10 CFR 431.462 consistent with the definition recommended by the CPWG. Specifically, DOE proposes the following definition for circulator pump:

Circulator pump

is a pump that is either a wet rotor circulator pump; a dry rotor, two-piece circulator pump; or a dry rotor, three-piece circulator pump. A circulator pump may be distributed in commerce with or without a volute.

DOE requests comment on the proposed definition for circulator pump.

The definitions of the pump categories that comprise the scope of “circulator pump” are addressed in the following section. In response to the May 2021 RFI, China asserted that the range and definition of circulator pumps is not clear and that schematic diagrams should be provided for each product on the basis of their text description. (China, No. 111 at p. 3) DOE believes that the proposed definition of circulator pump, in combination with the proposed definitions of the three primary kinds of circulator pumps in the following section, sufficiently address the range of circulator pumps, and that schematic diagrams would not provide additional benefit.

3. Definition of Circulator Pump Varieties

In the May 2021 RFI, DOE requested comment on the CPWG's recommended definitions for wet rotor circulator pump; dry rotor, two-piece circulator pump; dry rotor, three-piece circulator pump; and horizontal motor, including whether any changes in the market since the CPWG's recommendations would affect the recommended definitions and scope. 86 FR 24516, 24520-24521.

HI, Grundfos, and the CA IOUs generally agreed with the CPWG's recommended definitions for these varieties of circulator pumps. (HI, No. 112 at p. 2; Grundfos, No. 113 at p. 1; CA IOUs, No. 116 at p. 5) Other comments expressed support for the CPWG recommendations generally, as discussed in section III.A of this document.

As discussed previously, the CPWG recommended definitions for wet rotor circulator pump; dry rotor, two-piece circulator pump; and dry rotor, three-piece circulator pump were based on review of the descriptions of circulator pump categories established in the standard ANSI/HI 1.1-1.2-2014. DOE notes that the updated version of this industry standard, ANSI/HI 14.1-14.2-2019, “Rotodynamic Pumps for Nomenclature and Definitions,” has revised the descriptions of circulator pump categories to be identical to the CPWG recommended definitions, and section 41.5.1.5.1 of HI 41.5-2021 also includes definitions identical to the CPWG recommended definitions. DOE has reviewed the CPWG recommended definitions and has tentatively determined that these definitions appropriately distinguish the varieties of circulator pumps available on the market and as originally described in the industry standard ANSI/HI 1.1-1.2-2014.

Based on the discussion in the prior paragraphs, DOE proposes to adopt definitions for wet rotor circulator pump; dry rotor, two-piece circulator pump; and dry rotor, three-piece circulator pump at 10 CFR 431.462 as recommended by the CPWG and supported by stakeholder comments.

DOE currently defines a “horizontal motor” as a motor that requires the motor shaft to be in a horizontal position to function as designed, as specified in the manufacturer literature. 10 CFR 431.462. The definition of “horizontal motor” is used in 10 CFR 431.462 to exclude certain pumps from the IL pump category.

The definition of “horizontal motor” recommended by the CPWG includes the additional phrase “under typical operating conditions” to qualify “function as designed.” The CPWG discussed that this qualifier was added to address the potential that a motor would not be covered as a horizontal motor if a manufacturer were to advertise its circulator pump as being able to be installed in a non-horizontal orientation under certain conditions, such as high operating pressure (

i.e.,

conditions other than typical conditions). (Docket No. EERE-2016-BT-STD-0004, No. 64 at pp. 75-83) The CPWG discussed that the requirement to consider motor installation in the context of typical operating conditions, as specified in the manufacturer literature, would address this potential. (Docket No. EERE-2016-BT-STD-0004, No. 66 at pp. 55-57) 86 FR 24516, 24520. DOE did not receive any comments on the definition of horizontal motor in response to the May 2021 RFI.

The definition of IL pumps includes the following sentence: “Such pumps do not include pumps that are mechanically coupled or close-coupled, have a pump power output that is less than or equal to 5 hp at BEP at full impeller diameter, and are distributed in commerce with a horizontal motor.” 10 CFR 431.462.

DOE has reviewed the horizontal motor definitions and has tentatively concluded that the existing definition of horizontal motor in 10 CFR 431.462 could benefit from additional specificity. However, DOE does not believe the term “typical operating conditions” recommended by the CPWG provides sufficient specificity, as the term could refer to any conditions specified in the manufacturer's manual. In order to address the concern that a pump with a horizontal motor would be considered an IL pump instead of a circulator pump if the motor must be non-horizontal under non-typical conditions such as high operating pressure, DOE instead proposes the following definition of horizontal motor, consistent with the intent of the CPWG:

Horizontal motor

means a motor, for which the motor shaft position when functioning under operating conditions specified in manufacturer literature, includes a horizontal position.

DOE has tentatively concluded that this proposed update to the horizontal motor definition would provide additional specificity, but would not in practice change the pumps currently excluded from the IL pump definition (and now proposed to be included in the circulator pump definition) through use of the term.

DOE requests comment on the proposed definition for horizontal motor, including whether it meets the intent of the CPWG or whether it would include other motors not intended to be captured in the definition.

4. Definition of Circulator-Less-Volute and Header Pump

In the May 2021 RFI, DOE discussed that some circulator pumps are distributed in commerce as a complete assembly with a motor, impeller, and volute, while other circulator pumps are distributed in commerce with a motor and impeller, but without a volute (herein referred to as “circulators-less-volute”). Some circulators-less-volute are solely intended to be installed in other equipment, such as a boiler, using a cast piece in the other piece of equipment as the volute, while others can be installed as a replacement for a failed circulator pump in an existing system or newly installed with a paired volute in the field. 86 FR 24516, 24521; (Docket No. EERE-2016-BT-STD-0004, No. 47 at pp. 371-372; Docket No. EERE-2016-BT-STD-0004, No. 70 at p. 99) As discussed in the May 2021 RFI, CPWG asserted that circulator pumps distributed in commerce without volutes meet the definition of pump, and that not subjecting such equipment to test procedures and standards would represent a significant loophole. 86 FR 24516, 24521; (Docket No. EERE-2016-

BT-STD-0004, No. 70 at pp. 89-91; No. 74 at pp.383-403) The CPWG also discussed that including circulators-less-volute within the scope of DOE regulation is consistent with the treatment of circulator pumps under the European Union's regulations

which applies to circulator pumps “with or without housing.” (Docket No. EERE-2016-BT-STD-0004, No. 74 at pp. 373-376)

See EC No 622/2012;

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex:32012R0622.

As noted in the May 2021 RFI, the CPWG also discussed that circulators-less-volute that are solely intended to be installed in other equipment use the other equipment as the volute, and do not have a matching volute that is separately distributed in commerce and, therefore, would not pose the same loophole risk. According to the CPWG, such pumps would also be difficult to test and rate. Specifically, the CPWG discussed that circulator pump manufacturers would not have access to or design authority for the volute design. In addition, the circulator pump could not be tested as a standalone circulator pump because the volute would be unable to be removed from the other equipment, and no paired volute would be distributed in commerce with which the header pump could be tested. According to the CPWG, such equipment would potentially require extensive and burdensome equipment to test appropriately. As such, the CPWG recommended excluding circulator pumps that are distributed in commerce exclusively to be incorporated into other OEM equipment, such as boilers or pool heaters. (Docket No. EERE-2016-BT-STD-0004, No. 74 at pp. 413-416) 86 FR 24516, 24521.

As stated in the May 2021 RFI, the CPWG suggested referring to circulator-less-volute that are intended solely for installation in another piece of equipment and do not have a paired volute that is distributed in commerce as “header pumps.” (Docket No. EERE-2016-BT-STD-0004, No. 74 at pp. 384-386). The CPWG recommended defining “header pump” as a pump that consists of a circulator-less-volute intended to be installed in an OEM piece of equipment that serves as the volute, and to exclude them from the recommended circulator pump test procedure and standards. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #2B at p. 2); 86 FR 24516, 24521. The CPWG also recommended that for header pumps distributed in commerce with regulated equipment, DOE should consider modifying the test procedure and metric for such regulated equipment during the next round of applicable rulemakings to account for the energy use of header pumps in a modified metric. For header pumps distributed in commerce with non-regulated equipment, the CPWG recommended that DOE should consider test procedures and standards for such pumps or equipment at a later date. (Docket No. EERE-2016-BT-STD-0004, No. 58 Non-Binding Recommendation to the Secretary #2 at p. 10)

In the May 2021 RFI, DOE requested comment on the definition of header pump. 86 FR 24516, 24521. HI agreed with the CPWG recommended definition of “header pump,” stating that no substantive changes have occurred in the market, and that such pumps should be excluded from regulation. (HI, No. 112 at p. 2) NEEA supported the recommended definition of “header pump” and the recommended exclusion of them, noting that they are challenging to test. NEEA also commented that DOE should monitor the market for header pumps and make sure it does not become a loophole after regulation. (NEEA, No. 115 at p. 3) Grundfos stated that no change to the definition is warranted, but that header pumps should be regulated in the same way that circulators-less-volute are regulated;

i.e.,

by requiring a reference volute for testing, as is required in the EU, in order to avoid creating a loophole. (Grundfos, No. 113 at p. 1-2). China stated that the test method for header pumps has not been provided and that DOE should define the test method for these pumps. (China, No. 111 at p. 3)

DOE notes that HI 41.5-2021 does not address either header pumps or circulators-less-volute. DOE tentatively agrees that a circulator-less-volute designed solely for use as a component in a separate piece of equipment should be distinguished from circulators-less-volute generally for the purpose of the proposed test procedure for the reasons discussed by the CPWG. As discussed in section III.E.2.b, the CPWG recommended specific test procedure provisions for circulators-less-volute that are not designed solely for installation in a separate piece of equipment (

i.e.,

a header pump). (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #12 at p. 2) To provide a distinction between a circulator-less-volute and a header pump, DOE proposes additional detail within the definition of header pump recommended by the CPWG and to add a definition of circulator-less-volute to be mutually exclusive from the definition of a header pump. These definitions proposed by DOE are as follows:

Header pump

means a circulator pump distributed in commerce without a volute and for which a paired volute is not distributed in commerce. Whether a paired volute is distributed in commerce will be determined based on published data, marketing literature, and other publicly available information.

Circulator-less-volute

means a circulator pump distributed in commerce without a volute and for which a paired volute is also distributed in commerce. Whether a paired volute is distributed in commerce will be determined based on published data, marketing literature, and other publicly available information.

DOE requests comment on the proposed definitions of header pump and circulator-less-volute.

DOE acknowledges that EU Regulation No 622/2012 includes provisions to test circulator pumps integrated in products dismantled from the product and measured with a reference pump housing, which means “a pump housing supplied by the manufacturer with inlet and outlet ports on the same axis and designed to be connected to the pipework of a heating system or secondary circuit of a cooling distribution system.”

As stated previously, the CPWG discussed that there would be no available paired volutes with which to test a header pump, and as such testing such pumps would require extensive and potentially burdensome equipment to test appropriately. In its comments recommending that use of a reference volute should be required for testing header pumps, Grundfos has not sufficiently addressed these testing concerns for header pumps raised by the CPWG. In addition, DOE tentatively concludes that requiring testing of header pumps using a reference volute may result in a rating that is not representative of its energy use in the equipment for which it is designed, and that assessing header pump energy use within broader equipment categories in which they are embedded, such as boilers, may be more appropriate. As such, DOE is not proposing to include header pumps in the scope of this test procedure, and accordingly is not proposing a test method for header pumps.

European Commission Regulation No 622/2012 of 11 July 2012 amending Regulation (EC) No 641/2009 with regard to ecodesign requirements for glandless standalone circulators and glandless circulators integrated in products.

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0622. Accessed 2021-09-21.

5. Definition of On-Demand Circulator Pumps

In the May 2021 RFI, DOE stated that on-demand circulator pumps are designed to maintain hot water supply within a temperature range by activating in response to a signal, such as user presence. The CPWG recommended a definition for “on-demand circulator pumps” to be incorporated as necessary. (Docket No. EERE-2016-BT-STD-0004, No. 98 Non-Binding Recommendation #1 at pp. 4-5) 86 FR 24516, 24521. Discussion during CPWG meetings suggested that the purpose of recommending a definition for on-demand circulator pumps would be to allow for the possibility of considering them as a separate equipment class with a different standard level, while still applying the metric and test procedure to them. (Docket No. EERE-2016-BT-STD-0004-0069, p. 199) The CPWG recommended defintion for “on-demand circulator pumps” is as follows:

“On-demand circulator pump” means a circulator pump that is distributed in commerce with an integral control that:

• Initiates water circulation based on receiving a signal from the action of a user [of a fixture or appliance] or sensing the presence of a user of a fixture and cannot initiate water circulation based on other inputs, such as water temperature or a pre-set schedule.

• Automatically terminates water circulation once hot water has reached the pump or desired fixture.

• Does not allow the pump to operate when the temperature in the pipe exceeds 104 °F or for more than 5 minutes continuously.

(Docket No. EERE-2016-BT-STD-0004, No. 98 Non-Binding Recommendation #1 at pp. 4-5); 86 FR 24516, 24521.

In addition, the CPWG recommended that an on-demand circulator pump must not be capable of operating without the control without physically destructive modification of the unit, such as any modification that would violate the product's standards listing. (Docket No. EERE-2016-BT-STD-0004, No. 98 Non-Binding Recommendation #1 at p. 5); 86 FR 24516, 24521.

DOE requested comment regarding the CPWG-recommended definition of “on-demand circulator pump” and whether it is appropriate to retain on-demand circulator pumps within the scope of future analysis. 86 FR 24516, 24521.

HI agreed with the recommended definition of on-demand circulator pumps and stated that the CPWG intention of defining them was for the purpose of possible exclusion from standards due to limited run hours. (HI, No. 112 at p. 3) Grundfos commented that on-demand products should be regulated as circulator pumps because they are built with standard circulator pumps that incorporate additional features, and that having them unregulated would create a loophole allowing less-efficient induction-based products to remain on the market. (Grundfos, No. 113 at p. 1-2) NEEA agreed with the recommended definition of on-demand circulator pumps, but did not agree that they should be treated separately by DOE regulations. NEEA commented that these pumps can save energy by reducing run time, and that these savings are not addressed in the recommended test method. NEEA recommended that in a future rulemaking, DOE consider the potential energy savings from domestic hot water run-hour controls and consider providing a ratings credit for circulator pumps equipped with efficient temperature, on-demand, timer, or learning run-hour controls. (NEEA, No. 115 at p. 4).

DOE notes that HI 41.5-2021 does not address or refer to on-demand circulator pumps. The CPWG discussed that on-demand controls do not reduce the speed of the pump, but rather reduce the hours of use. Pumps with on-demand controls could also have speed controls, which the recommended metric would capture. (Docket No. EERE-2016-BT-STD-0004-0069, p. 172-173) In addition, CPWG members discussed that the extent to which time-based controls are used is unknown (

Id.

at p. 176), and that rather than attempting to capture it in the metric, utility programs could consider prescriptive rebates associated with these controls. (

Id.

at p. 178) In addition, CPWG members suggested that legionella concerns would limit the application of on-demand controls.

(

Id.

at p. 195-196)

As discussed in the transcript, situations where water is stagnant and the temperature drops can result in growth of legionella.

DOE proposes to define on-demand circulator pump at 10 CFR 431.462 as recommended by the CPWG. DOE believes that the recommended added specification that the on-demand circulator pump must not be capable of operating without the control without physically destructive modification of the unit, such as any modification that would violate the product's standards listing, is already encompassed by the provision in the recommended definition that the control be “integral” and by the definition of “integral” in 10 CFR 431.462: a part of the device that cannot be removed without compromising the device's function or destroying the physical integrity of the unit.

DOE is not proposing to exclude on-demand circulator pumps from the scope of the test procedure. At this time, DOE has not considered developing a credit for these controls, as was suggested in comments. DOE notes that if on-demand circulator pumps are equipped with other controls that reduce speed as defined in section III.D.1, they may be tested according to the relevant test methods rather than using the no controls test. DOE will consider whether standards are appropriate for this equipment in a future energy conservation standards rulemaking.

DOE requests comment on its proposal to include on-demand circulator pumps within the scope of this test procedure. DOE also requests data and information that would justify a CEI credit for on-demand circulator pumps.

6. Applicability of Test Procedure Based on Pump Configuration

In addition to recommending specific definitions, the CPWG also discussed and provided recommendations pertinent to the scope of applicability of the recommended circulator pumps test procedure. The CPWG recommended that the scope of the recommended test procedure would be limited to wet rotor circulator pumps, dry rotor close-coupled circulator pumps, and dry rotor mechanically-coupled circulator pumps, as discussed in section III.B.2. (Docket No. EERE-2016-BT-STD-0004, No. 58, Recommendation #1A, at p. 1) The CPWG also recommended to limit the scope of the circulator pump rulemaking to clean water pumps only and to exclude header pumps and submersible pumps. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #2A and 2B at p. 2)

In the January 2016 TP final rule, DOE established a definition for “clean water pump.” 81 FR 4046, 4100 (Jan. 25, 2016). DOE noted that several common pumps would not meet the definition of clean water pumps, as they are not designed for pumping clean water, including wastewater, sump, slurry, or solids handling pumps; pumps designed for pumping hydrocarbon product fluids; chemical process pumps; and sanitary pumps.

Id.

at 4100. The CPWG reviewed this definition and, to be consistent with the general pumps rulemaking, recommended to limit the scope of the circulator pump

rulemaking to clean water pumps only, whereby clean water pump means a pump that is designed for use in pumping water with a maximum non-absorbent free solid content of 0.016 pounds per cubic foot (0.25 kilograms per cubic meter), and with a maximum dissolved solid content of 3.1 pounds per cubic foot (50 kilograms per cubic meter), provided that the total gas content of the water does not exceed the saturation volume, and disregarding any additives necessary to prevent the water from freezing at a minimum of 14 °F (−10 °C), as defined at 10 CFR 431.462. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #2A at p. 2) The CPWG discussed how this was important to ensure certain small, chemical process pumps would be excluded based on the fact that they are not designed to pump clean water. (Docket No. EERE-2016-BT-STD-0004, No. 70 at pp. 36-42)

DOE did not receive any comments on the May 2021 RFI related to the CPWG recommendation to limit scope of the circulator pump rulemaking to clean water pumps. DOE agrees with the CPWG that limiting the scope of the circulator pump rulemaking to clean water pumps, consistent with the scope of general pumps in 10 CFR 431.464, is appropriate. Regulation of chemical process pumps would require many other considerations beyond that for clean water pumps, and DOE believes that excluding small chemical process pumps from the scope of regulation would not create any loophole risks to the clean water circulator pump market. DOE proposes to apply the existing clean water pump definition to circulator pumps, thus limiting the scope of applicability of the proposed circulator pumps test procedure to circulator pumps that meet the definition of clean water pump.

Regarding the exclusion of submersible pumps, the CPWG discussed a variety of close-coupled, wet rotor pumps that are typically used for decorative water features in swimming pools and ponds. (Docket No. EERE-2016-BT-STD-0004, No. 70 at pp. 47-63 and No. 47, pp. 523-525) The CPWG discussed how these decorative water feature pumps might otherwise meet the definition of a wet rotor circulator pump (see section III.B.2); however, these pumps are unique from traditional wet rotor circulator pumps, in that they are submersible pumps and, as such, are intended to be operated with the entire pump and motor assembly fully submerged in the pumped liquid. Therefore, the CPWG recommended to exclude submersible pumps from the scope of applicability of any circulator pump test procedure and standards. (Docket No. EERE-2016-BT-STD-0004, No. 74 at pp. 299-303)

In response to the May 2021 RFI, HI agreed with the scope agreed to by the CPWG. (HI, No. 112 at p. 3)

DOE agrees with the CPWG that submersible decorative water feature pumps are similar in design to wet rotor circulator pumps in that they are wet rotor, rotodynamic pumps, but that they are intended to be operated with the entire pump and motor assembly fully submerged in the pumped liquid, which presents additional considerations for any test procedure and energy conservation standards. Given that these decorative water feature pumps are submersible, DOE does not believe that if unregulated they would pose any loophole risk to the clean water circulator pump market. Therefore, DOE proposes to exclude submersible pumps from the scope of applicability of the circulator pump test procedure. DOE notes that the definition of submersible pump recommended by the CPWG is identical to the definition that currently exists in 10 CFR 431.462, as adopted in the August 2017 DPPP TP final rule. 82 FR 36858, 36922. As such, DOE is not proposing amendments to that definition.

As discussed in section III.B.4, DOE tentatively agrees with the recommended exclusion of header pumps and tentatively agrees with the inclusion of circulators-less volute. Also, as discussed in section III.B.5, DOE proposes to include on-demand circulator pumps within the scope of this test procedure. In summary, DOE proposes that the test procedure would be applicable to circulator pumps (as defined in section III.B.2) that are clean water pumps, including circulators-less-volute and on-demand circulator pumps, and excluding header pumps and submersible pumps. The specific test methods proposed for circulator pumps are discussed in more detail in section III.D of this document.

DOE requests comment on the proposed scope of applicability of the circulator pump test procedure to circulator pumps that are clean water pumps, and the exclusion of header pumps and submersible pumps from the scope of the proposed test procedure.

7. Basic Model

In the course of regulating consumer products and commercial and industrial equipment, DOE has developed the concept of a “basic model” to determine the specific product or equipment configuration(s) to which the regulations would apply. For the purposes of applying the proposed circulator pump regulations, DOE is also proposing to rely on the definition of “basic model” as currently defined at 10 CFR 431.462. Application of the current definition of “basic model” would allow manufacturers of circulator pumps to group similar models within a basic model to minimize testing burden, while ensuring that key variables that differentiate circulator pump energy performance or utility are maintained as separate basic models. As proposed, manufacturers would be required to test only a representative number of units of a basic model in lieu of testing every model they manufacture. As proposed, individual models of circulator pumps would be permitted to be grouped under a single basic model so long as all grouped models have the same representative energy performance, which is representative of the least efficient or most consumptive unit.

Specifically, for pumps, DOE's existing definition of basic model is as follows:

Basic model

means all units of a given class of pump manufactured by one manufacturer, having the same primary energy source, and having essentially identical electrical, physical, and functional (or hydraulic) characteristics that affect energy consumption, energy efficiency, water consumption, or water efficiency; and, in addition, for pumps that are subject to the standards specified in 10 CFR 431.465(b), the following provisions also apply:

(1) All variations in numbers of stages of bare RSV and ST pumps must be considered a single basic model;

(2) Pump models for which the bare pump differs in impeller diameter, or impeller trim, may be considered a single basic model; and

(3) Pump models for which the bare pump differs in number of stages or impeller diameter and which are sold with motors (or motors and controls) of varying horsepower may only be considered a single basic model if:

(i) For ESCC, ESFM, IL, and RSV pumps, each motor offered in the basic model has a nominal full load motor efficiency rated at the Federal minimum (see the current table for NEMA Design B motors at § 431.25) or the same number of bands above the Federal minimum for each respective motor horsepower (see Table 3 of appendix A to subpart Y of this part); or

(ii) For ST pumps, each motor offered in the basic model has a full load motor efficiency at the default nominal full load submersible motor efficiency shown in Table 2 of appendix A to subpart Y of this part or the same number of bands above the default nominal full load submersible motor efficiency for each respective motor horsepower (see Table 3 of appendix A to subpart Y of this part).

10 CFR 431.462

DOE has reviewed this definition and has tentatively determined that the general definition is appropriate for circulator pumps. DOE understands that, like dedicated purpose pool pumps, circulator pumps are exclusively single-stage pumps and, therefore, the provision regarding variation in number of stages would not be applicable. Furthermore, DOE understands that, like each dedicated purpose pool pump motor model, each circulator pump model is offered with only one impeller diameter, unlike general pumps for which a given pump model may be sold with many different impeller diameters that are customized for each application. Therefore, DOE believes that the provision for grouping individual pumps that vary only in impeller diameter, or impeller trim, would also not be applicable to circulator pumps; any variation in impeller trim would constitute a separate basic model for circulator pumps. Finally, as neither the multistage nor impeller trim specifications for basic model designation apply to circulator pumps, the provision regarding variation in motor horsepower resulting from variation in either of those characteristics would also not apply to circulator pumps. Therefore, only the general provisions of the basic model definition would be applicable to circulator pumps and no additional provisions specific to circulator pumps would be necessary.

DOE requests comment on the proposed applicability of the definition of “basic model” at 10 CFR 431.462 to circulator pumps and any characteristics unique to circulator pumps that may necessitate modifications to that definition.

C. Rating Metric

As discussed in the May 2021 RFI, the CPWG focused on defining a performance-based metric that was similar to the PEI metric established for the January 2016 TP final rule. (Docket No. EERE-2016-BT-STD-0004, No. 64 at pp. 246-247) The CPWG recommended using the PEI

CIRC

metric, which would be defined as the pump energy rating (“PER”) for the rated circulator pump model (“PER

CIRC

”), divided by the PER for a circulator pump that is minimally compliant with energy conservation standards serving the same hydraulic load (“PER

CIRC,STD

”). (Docket No. EERE-2016-BT-STD-0004, No. 58, Recommendation #5 at p. 4); 86 FR 24516, 24522.

The equation for PEI

CIRC

as recommended by the CPWG is shown in the equation (1):

EP20DE21.000

Where:

PER

CIRC

= circulator pump energy rating (hp); and

PER

CIRC,STD

= pump energy rating for a minimally compliant circulator pump serving the same hydraulic load.

(Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #5 at p. 4); 86 FR 24516, 24522.

As stated in the May 2021 RFI, PER

CIRC

would be determined as the weighted average input power to the circulator pump motor or controls, if available, to a given circulator pump over a number of specified load points. Due to differences in the various control varieties available with circulator pumps, the CPWG recommended that each circulator pump control variety have unique weights and test points that are used in determining PER

CIRC

(Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #6A and #6B at pp. 4-6) 86 FR 24516, 24522. The test points, weights, and test methods necessary for calculating PER

CIRC

for pressure controls, temperature controls, manual speed controls, external input signal controls, and circulator pumps with no control (

i.e.,

without external input signal, manual, pressure, or temperature control)

are described in section III.D. 86 FR 24516, 24522.

In order to determine weighted average input power, input power must be measured at multiple test points, and each test point must be weighted. The test points and weights for each test method are discussed in section III.D.

In this document, circulator pumps with “no controls” are also inclusive of other potential control varieties that are not one of the specifically identified circulator pump control varieties. Any circulator pump without one of the defined control varieties would be treated as a circulator pump with no controls, regardless of whether it is a single-speed circulator pump or has a control variety not defined in this test procedure. See section III.D.7 of this document.

As recommended by the CPWG, PER

CIRC,STD

would be determined similarly for all circulator pumps, regardless of control variety. PER

CIRC,STD

would represent the weighted average input power to a minimally compliant circulator pump serving the same hydraulic load. As such, PER

CIRC,STD

would essentially define the minimally compliant circulator pump performance, such that the energy conservation standard level would always be defined as 1.00, and lower numbers would represent better performance. The CPWG discussed the derivation of PER

CIRC,STD

in the Working Group negotiations and, ultimately, recommended a standard level that is nominally equivalent to a single-speed circulator pump equipped with an electrically commutated motor. (Docket No. EERE-2016-BT-STD-0004, No. 102 at pp. 53-56; Docket No. EERE-2016-BT-STD-0004, No. 98 Recommendations #1 and 2A-D at pp. 1-4); 86 FR 24516, 24522.

The CPWG specified a method for determining PER

CIRC,STD

with procedures to determine the minimally compliant overall efficiency at the various test points based on the hydraulic performance of the rated circulator pump. (Docket No. EERE-2016-BT-STD-0004, No. 98 Recommendations #1 and 2A-D at pp. 1-4); 86 FR 24516, 24522. As discussed, PER

CIRC,STD

would represent the energy efficiency of a circulator pump that is minimally compliant with the applicable energy conservation standard, should DOE establish such a standard. Were DOE to conduct a rulemaking to propose energy conservation standards for circulator pumps, DOE would discuss in detail the derivation of PER

CIRC,STD,

as well as an analysis as required by EPCA to evaluate any such standard level to determine the level designed to achieve the maximum improvement in energy efficiency that is technologically feasible and economically justified, as required under EPCA.

DOE notes that the recommended method for determining PER

CIRC,STD

relies on the

hydraulic horsepower of the rated circulator pump. DOE discusses measurement of this parameter in section III.G.

For more information on any energy conservation standard rulemaking for circulator pumps see Docket No. EERE-2016-BT-STD-0004.

DOE requested comment on the CPWG recommendation to adopt PEI

CIRC

as the metric to characterize the energy use of certain circulator pumps and on the recommended equation for PEI

CIRC,

including whether anything in the technology or market has changed since publication of the 2016 Term Sheets that would lead to this metric no longer being appropriate. 86 FR 24516, 24522.

In response, HI and Grundfos recommended changing the metric nomenclature from PEI

CIRC

to CEI (Circulator Energy Index) to avoid confusion and/or differentiate coverage from the general pump rule. (HI, No. 112 at p. 3; Grundfos, No. 113 at p. 2) HI similarly recommended corresponding changes to PER

CIRC

to CER (Circulatory Energy Rating). (HI, No. 112 at p. 3). As stated in section III.E.1, the Advocates and NEEA supported adopting HI 41.5-2021, the industry rating guideline, that includes the updated metric nomenclature discussed by HI in its comments. (Advocates, No. 114 at p. 1; NEEA, No. 115 at p. 4-5). The CA IOUs also supported modifying the term sheet to adopt HI 41.5-2021, and supported adopting term sheet provisions including the definition of CEI. (CA IOUs, No. 116 at p. 2, 5)

DOE agrees with the CPWG that the recommended PEI

CIRC

metric, as shown in equation (1), will reasonably reflect the energy use of circulator pumps over a representative average use cycle. DOE also agrees with commenters that changing the name of the metric to CEI will reduce possibility for confusion. As such, DOE proposes to adopt the CEI metric as the performance-based metric for representing the energy performance of circulator pumps, as defined in equation (2), and consistent with section 41.5.3.2 of HI 41.5-2021. DOE notes that while HI 41.5-2021 defines the denominator as CER

REF

, DOE believes that the terminology CER

STD

is more reflective of the Federal energy conservation standards. Any standards considered for any circulator pumps for which the CEI is applicable would use this metric as a basis for the standard level.

EP20DE21.001

Where:

CER = circulator energy rating (hp); and

CER

STD

= circulator energy rating for a minimally compliant circulator pump serving the same hydraulic load.

DOE requests comment on its proposal to adopt CEI as the metric to characterize the energy use of certain circulator pumps and on the proposed equation for CEI.

D. Test Methods for Different Circulator Pump Categories and Control Varieties

Many circulator pumps are sold with a variable speed drive and controls (

i.e.,

logic or user interface) with various control strategies that reduce the required power input at a given flow rate to save energy. The primary varieties of control recommended by the CPWG include manual speed controls, pressure controls, temperature controls, and external input signal controls. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #4 at p. 4) In order for the test procedure to produce results that reflect variations in energy consumption associated with the various control strategies that could be implemented in a circulator pump, the CPWG recommended that DOE establish different test methods for each control variety in the circulator test procedure. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #6A and #6B at pp. 4-6)

Manual speed controls are controls in which the speed of the motor is adjusted manually, typically at the time of installation, to match the system head and flow requirements of the installation.

Pressure controls are controls that use a variable speed drive to automatically adjust the speed of the motor based on the pressure in the system at any given time according to a fixed constant or proportional (

i.e.,

sloped) control curve.

Models with pressure controls typically provide several fixed control curve options available to accommodate different systems with varying pressure drops across different zones. These controls are typically installed in multi-zone hydronic heating applications to vary the speed of the circulator pump, based on the number of zones open, in order to achieve the appropriate flow rate through each zone.

Constant pressure control curves supply the same non-zero head pressure regardless of flow. Proportional pressure control curves reduce head in response to a reduction in flow, but maintain a minimum head pressure at zero flow.

Adaptive pressure controls are a specific variety of pressure controls that use pressure sensors to continually evaluate the head and flow requirements in the system and adjust the sensitivity of the control response

to specifically suit the system's head and flow requirements. In addition to being designed to operate in multi-zone systems, adaptive pressure controls may also have the ability to operate in a single zone system, such as a domestic hot water recirculation system, to adjust for any oversizing that might have occurred in the design and pump selection process. As such, adaptive pressure controls have the potential to save more energy than conventional (

i.e.

non-adaptive) pressure-based controls.

In adaptive pressure controls, the sensitivity of the control response is adjusted by changing the slope of the control curve.

Temperature controls are controls that use a variable speed drive to automatically adjust the speed of the pump continuously over the operating speed range to respond to a change in temperature in the system. These controls may be installed in single- or multi-zone systems and adjust the circulator pump's operating speed to provide the optimum flow rate based on the heat load in each zone. Specifically, temperature controls are typically designed to achieve a fixed temperature drop through the system and will adjust the speed of the pump to increase or decrease the flow rate to precisely match the required thermal load (

i.e.,

to maintain the target temperature drop). Unlike pressure controls, there are no minimum head requirements inherent to the temperature control, so temperature controls have the potential to use the least amount of energy to serve a given load.

Finally, external input signal control refers to a system in which the speed of the circulator pump is controlled by control logic that is external to the circulator pump. This could be the case

in circulator pumps that are, for example, designed to be installed in conjunction with a boiler and are controlled by the boiler's firing controls, as opposed their own internal control logic.

Section III.D.1 discusses DOE's proposed definitions for each of these circulator pump control varieties.

Section III.D.2 discusses the proposed reference system curve that serves as a basis for rating each variety of circulator pump controls.

Sections III.D.3 through III.D.7 discuss the specific test provisions being proposed for pressure controls, temperature controls, manual speed controls, external input signal controls, and no controls,

respectively.

In this document, circulator pumps with “no controls” are also inclusive of other potential control varieties that are not one of the specifically identified control varieties. See section III.D.7 of this document.

In response to the May 2021 RFI, several stakeholders commented about components of CEI that differ by control type method. China stated that DOE should offer the specific data or calculation method for CER

STD

and have executive consultation among World Trade Organization members before the procedure is officially published and implemented. China also commented that the weighted average input power for CEI is set differently than the international general rules, and requested that DOE offer scientific evidence for the weight assignment. (China, No. 111 at p. 3) Grundfos stated that the weights used in determining CEI should be aligned across control modes to simplify testing and that the baseline calculation method should match the control method weights. (Grundfos, No. 113 at p. 3) The CA IOUs supported the weighting points provided in the CPWG term sheets. (CA IOUs, No. 116 at p. 5)

In response to China and Grundfos, DOE discusses the weighting assignments in the individual test methods within this section. In general, the CPWG recommended unique weights for most control varieties, which were understood to be representative of their operation in the field. (See sections III.D.3, III.D.4, III.D.5, and III.D.6. of this NOPR)

HI 41.5-2021 section 41.5.3 specifies rating the most consumptive and least consumptive of the control curves that are available on a circulator pump as shipped. The industry test standard provides an example stating that if pressure control is the most consumptive option and multiple pressure control curve settings are provided, the circulator pump would be tested and rated per the pressure control test method, but with the most and least consumptive control curves. DOE notes that this example does not seem consistent with the preceding text, and that in the HI Energy Rating portal for circulator pumps,

the most consumptive rating is always based on full speed (no controls), while the least consumptive rating is based on one of the control varieties on-board, if any.

The HI Energy Rating portal is available at

er.pumps.org/circulator/ratings.

In response to the May 2021 RFI, HI stated that for clarity, and to align with the CPWG negotiated intent (referencing page 473 of the CPWG transcript from July 13, 2016), DOE should implement the least consumptive control mode CEI for the regulatory rating. (HI, No. 112 at p. 2)

NEEA commented that in the context of the CPWG recommendation, they would expect most manufacturers to rate with the least consumptive control curve available, which would encourage manufacturers to produce circulator pumps with efficient controls and would enable utilities to identify equipment with efficient control options. NEEA also suggested that DOE also allow circulator pumps with multiple control options to be rated with the most consumptive control curve available, consistent with HI 41.5-2021. NEEA stated that allowing circulator pumps to have multiple ratings would encourage adoption of energy efficient options and technologies beyond the minimum threshold, while holding all manufacturers to a consistent standard of performance and providing information for consumers to fully understand the energy consumption of the equipment. (NEEA, No. 115 at p. 5)

The CPWG did not make a specific recommendation on how to select which control mode to use for a rating other than that for pressure controls, a manufacturer should be able to choose the tested control curve, when multiple options are available, but should report the control curve used and method of adjustment (

e.g.,

whether the rating was achieved through automatic speed adjustment, manual speed adjustment or through simulated pressure signal) to DOE with certification reporting. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #9 at p. 7)

If given the option to choose a control variety for rating, DOE expects that most manufacturers would choose the least consumptive control curve. DOE reviewed the transcript cited by HI and did not identify justification that the intent of the CPWG was to recommend testing the least consumptive control mode. DOE believes that proposing a least consumptive approach, as suggested by HI, could require manufacturers to conduct multiple tests to identify the least consumptive control curve, which may cause additional burden. DOE does not think it is likely that a requirement to identify the least consumptive control curve would provide additional benefits to manufacturers (beyond that from an allowance to choose a control curve to test) such as an incentive to develop energy efficient control strategies. DOE proposes the approach presented in the CPWG recommendation, which would allow manufacturers to select the control variety used for testing if multiple control varieties are available on the circulator pump. In response to NEEA's recommendation to also allow ratings with the most consumptive control curve available, DOE proposes in this NOPR that manufacturers may select multiple control varieties with which to test their circulator pumps. DOE will address certification reporting requirements in any future energy conservation standard rulemaking.

For more information on any energy conservation standard rulemaking for circulator pumps see Docket No. EERE-2016-BT-STD-0004.

DOE requests comment on the proposal to allow manufacturers to select the control variety used for testing if the circulator pump model is distributed in commerce with multiple control varieties. DOE specifically requests comment on whether DOE should instead require manufacturers to test a circulator pump model that offers multiple control varieties with the least consumptive control variety. DOE also requests comment on the burden that would be associated with such an approach.

1. Definitions Related to Circulator Pump Control Varieties

As stated in the May 2021 RFI, the CPWG recommended definitions for the following control varieties for circulator pumps: Manual speed control, pressure control, temperature control, and external input signal control. 86 FR 24516, 24523. The definitions of these pump control varieties recommended by the CPWG are as follows:

•

Manual speed control

means a control (variable speed drive and user interface) that adjusts the speed of a driver based on manual user input.

•

Pressure control

means a control (variable speed drive and integrated logic) that automatically adjusts the speed of the driver in response to pressure.

•

Temperature control

means a control (variable speed drive and integrated logic) that automatically adjusts the speed of the driver continuously over the driver operating speed range in response to temperature.

•

External input signal control

means a variable speed drive that adjusts the speed of the driver in response to an input signal from an external logic and/or user interface.

(Docket No. EERE-2016-BT-STD-0004, No. 58, Recommendation #4 at p. 4) 86 FR 24516, 24523.

DOE requested comment on the recommended definitions for manual speed control, pressure control, temperature control, and external input signal control. 86 FR 24516, 24523.

In response to the May 2020 RFI, HI agreed with the current scope and definition recommended by the CPWG and noted that the definitions have not been changed in the adoption of HI 41.5-2021. (HI, No. 112 at p. 4). Grundfos and the CA IOUs also agreed with these definitions for control methods (Grundfos, No. 113 at p. 3; CA IOUs, No. 116 at p. 5) As stated previously, NEEA and the Advocates in general supported the term sheet recommendations. (Advocates, No. 114. at p. 1; NEEA, No. 115 at p. 2) DOE notes that HI 41.5-2021 section 41.5.1.5.1 includes definitions for manual speed control, pressure control, temperature control, and external input signal control that are identical to the CPWG recommendations.

DOE has reviewed these definitions recommended by the CPWG and believes that the definitions appropriately describe the characteristics of the relevant circulator pump controls. Furthermore, DOE believes these definitions appropriately identify each type of control for the purpose of determining the applicable test method based on the characteristics of a circulator pump's control variety. Therefore, consistent with CPWG recommendations and continued stakeholder support, DOE proposes to define external input signal control, manual speed control, pressure control, and temperature control as recommended by the CPWG and consistent with HI 41.5-2021.

In the May 2021 RFI, DOE noted that the CPWG did not recommend a definition for adaptive pressure controls, although it did recommend a separate test procedure for them, because, as discussed by the CPWG, adaptive pressure controls are able to adjust the slope of the control curve to fit the system needs through an ongoing learning process inherent in the software. (Docket No. EERE-2016-BT-STD-0004, No. 72 at pp. 45-46) 86 FR 24516, 24523.

DOE requested comment on a possible definition for adaptive pressure control. 86 FR 24516, 24523. Grundfos generally objected to addressing adaptive pressure control in the DOE test procedure. (Grundfos, No. 113 at p. 3; see discussion in section III.D.3), but did not comment specifically on the definition.

DOE notes that HI 41.5-2021 section 41.5.1.5.1 includes the following definition for adaptive pressure control: “a pressure control that adjusts the control curve automatically based on the conditions of use.” DOE believes that this definition would benefit from additional clarity regarding the conditions to which the control responds; specifically, DOE proposes to define adaptive pressure control as follows:

Adaptive pressure control

means a pressure control that continuously senses the head requirements in the system in which it is installed and adjusts the control curve of the pump accordingly.

DOE requests comment on its proposed definition of adaptive pressure control.

In the May 2021 RFI, DOE requested comment on whether any additional control variety is now currently on the market and if it should be considered in this rulemaking. 86 FR 24516, 24523. In response, HI stated that it is not aware of any additional control methods. (HI, No. 112 at p. 4) NEEA recommended that in a future rulemaking, DOE consider the potential energy savings from domestic hot water controls, especially temperature-based controls. NEEA suggested that DOE consider providing a CEI credit for circulator pumps equipped with efficient temperature, on-demand, timer, or learning run-hour controls. (NEEA, No. 115 at p. 4)

DOE acknowledges that additional controls exist for circulator pumps that reduce run-time rather than reduce speed. DOE proposes to limit the promulgation of test methods in this rulemaking to those control varieties recommended by the CPWG, which include only controls that reduce speed, and may consider additional control varieties in future rulemakings. DOE discusses the concept of applying “credits” for on-demand controls in section III.B.5 of this document.

2. Reference System Curve

The May 2021 RFI stated that all recommended test methods for circulator pump control varieties, which involve variable speed control of the circulator pump, specify test points with respect to a representative system curve. That is, for circulator pumps with manual speed controls, pressure controls, temperature controls, or external input signal controls, a reference system curve is implemented to be representative of the speed reduction that is possible in a typical system to provide representative results. For circulator pumps with no controls, no reference system is required as measurements are taken at various test points along a pump curve at maximum speed only. 86 FR 24516, 24523.

Such a reference system curve describes the relationship between the head and the flow at each test point in a typical system. Additionally, a reference system curve that is representative of a typical system in which circulator pumps are installed may also allow for the differentiation of control varieties to be reflected in the resulting ratings. 86 FR 24516, 24523. The CPWG recommended that DOE incorporate a quadratic reference system curve, which intersects the BEP and has a static offset of 20 percent of BEP head, as shown in equation (3). (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #8 at pp. 6-7) 86 FR 24516, 24523.

EP20DE21.002

Where:

H = the pump total head (ft),

Q = the flow rate (gpm),

100%

= flow rate at 100 percent of BEP flow (gpm), and

100%

= pump total head at 100 percent of BEP flow (ft).

(Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #8 at pp. 6-7); 86 FR 24516, 24523.

In the May 2021 RFI, DOE requested comment on whether the CPWG-recommended reference system curve shape, including the static offset, is reasonable for circulator pumps. 86 FR 24516, 24523. HI, Grundfos, and the CA IOUs agreed with the recommended reference curve. (HI, No. 112 at p. 4; Grundfos, No. 113 at p. 3; CA IOUs, No. 116 at p. 5).

DOE notes that the reference curve in equation (3) is consistent with HI 41.5-2021, which includes this reference curve in each of the individual control test methods (sections 41.5.3.4.2 #3d, 41.5.3.4.3 #2, 41.5.3.4.4.1 #2, 41.5.3.4.4.2 #2, and 41.5.3.4.5 #2d). DOE has tentatively determined that the reference curve established for general pumps would provide representative results for circulator pumps. As such, DOE proposes to adopt the reference curve as shown in equation (3).

3. Pressure Control

As described in the May 2021 RFI, pressure controls are a variety of circulator pump control in which the variable speed drive is automatically adjusted based on the pressure in the system. For example, such controls are common in multi-zone hydronic heating applications where the flow and speed are adjusted in response to zones opening or closing. CPWG recommended that for all circulator pumps distributed in commerce with pressure controls, the PER

CIRC

should be calculated as the weighted average input power at 25, 50, 75, and 100 percent of BEP flow with unique weights shown in equation (4):

EP20DE21.003

Where:

PER

CIRC

= circulator pump energy rating (hp);

= weight of 0.05, 0.40, 0.40, and 0.15 at test points of 25, 50, 75, and 100 percent of BEP flow, respectively;

in,i

= power input to the driver at each test point i (hp); and

i = test point(s), defined as 25, 50, 75, and 100 percent of the flow at BEP.

(Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #6A at pp. 4-5 and #7 at p.6); 86 FR 24516, 24523-24524.

The CPWG recommended the weights of 0.05, 0.40, 0.40, and 0.15 at test points of 25, 50, 75, and 100 percent of BEP flow, respectively, based on subcommittee review of other relevant test methods that document the typical load profile of hydronic heating and/or cooling applications, including AHRI 550/590-2011 “Performance Rating Of Water-Chilling and Heat Pump Water-Heating Packages Using the Vapor Compression Cycle,” ASHRAE 103 “Method of Testing for Annual Fuel Utilization Efficiency of Residential Central Furnaces and Boilers, and EN 16297-1:2012 “Pumps. Rotodynamic pumps. Glandless circulators. General requirements and procedures for testing and calculation of energy efficiency index (EEI),” as well as the fact that pumps with pressure controls will unlikely operate near BEP flow because systems are sized to be able to meet the full demand of the design day, which occurs only on rare occasion.

This discussion took place during a CPWG subcommittee meeting, so there is no transcript in the docket. This presentation includes the results from the subcommittee:

https://www.regulations.gov/document/EERE-2016-BT-STD-0004-0027.

In addition to the test point flow rates, the test method for pressure controls must also specify the head values (or range of head values) for evaluation. For pressure controls, the head values associated with the specified flow rates are determined by the control curve of the pressure control being evaluated. Traditional pressure controls typically follow a fixed, linear control curve that can represent maintenance of constant pressure at a variety of different flow rates, or can reduce the pressure as the flow is reduced. Often, a single circulator pump will be equipped with a number of different pressure control options, as illustrated in Figure III.1.

The CPWG recommended testing circulator pumps with pressure controls using automatic speed adjustment based on the factory selected control setting, manual speed adjustment, or simulated pressure signal to trace a factory selected control curve setting that will achieve the test point flow rates with a head at or above the reference system curve. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #9 at p. 7) To test circulator pumps with pressure controls under this recommendation, manufacturers would select a pressure-based control curve for the purpose of the test procedure, provided that all of the head values that result from that are at or above the reference system curve discussed in section III.D.2. For example, Figure III.1 depicts three fixed pressure control options (low, medium, and high), but only the highest pressure control option results in head values that are all at or above the reference system curve. Under the CPWG's recommendation, the speed of the pump would be adjusted according to the selected control curve using one of three methods: Manual speed adjustment, simulated pressure signal, or automatic adjustment.

EP20DE21.004

The CPWG also recommended that if a circulator pump with pressure controls is tested with automatic speed adjustment, that the pump can be manually adjusted to achieve 100 percent BEP flow and head point at max speed. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #9 at p. 7); 86 FR 24516, 24524. DOE interpreted this to mean that the test point at 100 percent BEP flow and maximum speed may be generated using a combination of alternative speed control and throttling. This modification would be necessary in the event the manufacturer-selected control curve does not intersect the maximum speed pump curve at the BEP of the pump, as shown in Figure III.1. In such a case, the test point at 100 percent of BEP flow and maximum speed could be generated from the control curve at the maximum speed setting of the pump and throttled to reach the specific test point.

In the May 2021 RFI, DOE requested comment on the recommended test methods, test points, and weights for circulator pumps with pressure controls. 86 FR 24516, 24524.

HI recommended that DOE implement the testing methodology in HI 41.5-2021 section 41.5.3.4.2 for pressure control, which does not require all test points on a control curve to exist above the reference curve. Specifically, HI asserted that the minimum system control head should be the value at 25 percent BEP on the reference curve for the manual control (and pressure control) method. HI stated that it found that intersecting the pump curve at BEP and requiring the control mode to be above the reference curve was too limiting. HI asserted that this approach did not represent the controls available in the market, nor did it properly demonstrate the benefit of the onboard controls. HI stated that section 41.5.3.4.2 allows controls to be rated below the reference curve with power correction back to the reference curve. (HI, No. 112 at 4) HI stated that this change eliminates the need for all control curves to exist above the reference curve, allowing for a better presentation of control curves used in the market and for the circulator pump CEI values to better represent a pump's capabilities. (HI, No. 112 at p. 2) HI provided an additional appendix in support of its recommendation for the changes. (HI, No. 112 at p.11-12) Grundfos recommended that DOE accept the approach defined in HI 41.5 for calculating CEI that allows for constant pressure control methods to be rated across the entire curve. (Grundfos, No. 113 at p. 2)

The CA IOUs stated that experiences with field testing the metric on circulator pumps in the market led to discovering unintended challenges of testing both constant and proportional pressure controls in most applications. The CA IOUs noted that these products generally operate at head pressure below or significantly below the reference curve at one or more measurement points; thus, most programmed pressure control curves in a product are not testable under the

previous methodology. Some products do not have any pre-set control methods that meet all the requirements and thus must be tested as having no controls. The CA IOUs added that all of the below reference curve performance measurements remain valid after adjustment, since the adjustment uses an assumed constant efficiency calculation. The CA IOUs asserted that this ensures that products do not gain any arbitrary input power advantage from the head pressure below the reference curve adjustment. The CA IOUs stated that not addressing this issue would force DOE to grant numerous test procedure waivers. (CA IOUs, No. 116 at pp.2, 4-5)

DOE has reviewed the revised test method for pressure control in section 41.5.3.4.2 of HI 41.5-2021. DOE notes that HI 41.5-2021 does not include the CPWG recommendation to allow manual adjustment of automatic speed adjusted controls to achieve 100 percent BEP flow and head point at maximum speed (although this provision is included for adaptive pressure controls, discussed later in this section). As stated previously, DOE did not understand this recommendation to mean that the pressure control curve should intersect the pump curve at BEP, which HI noted in their comments was too limiting. However, section 41.5.3.4.2 #2a-c of HI 41.5-2021 in general allows for throttling in combination with any of the three recommended methods to adjust speed: Automatic speed adjustment based on the factory selected control setting, manual speed adjustment, or simulated pressure signal to trace a factory selected control curve setting. In addition, as noted by HI, HI 41.5-2021 also contains a requirement that the control curve setting must achieve 100 percent BEP flow of the reference curve. DOE understands this to mean that a control curve cannot include artificial limitations on speed. Otherwise, DOE understands that any control curve would be able to achieve 100 percent of BEP flow of the reference curve after intersecting with the maximum speed curve. Finally, DOE understands that the provision that the control must produce head equal to or greater than 25 percent of BEP head at a minimum of one test point is designed to limit testing of control curves that would not be viable in the field.

DOE agrees with commenters that it is important for the test method to capture the variety of pressure controls on the market, and that correction back to the reference curve would prevent any unfair advantage among the variety of controls on the market. DOE notes that in this proposal, all three curves depicted in Figure III.1 could be used in this test method. For all of these reasons, DOE is proposing a test method for circulator pumps with pressure controls consistent with the method included in HI 41.5-2021. Specifically, DOE proposes that circulator pumps with pressure controls be tested at test points of 25, 50, 75, and 100 percent of BEP flow based on a manufacturer-selected control curve that is available to the end user, must produce a head equal to or greater than 25 percent of BEP head at a minimum of one test point, and must achieve 100 percent BEP flow of the reference curve. DOE proposes that such the test points may be obtained based on automatic speed adjustment, manual speed adjustment, or simulated pressure signal, or a combination of these adjustments, including throttling. Additionally, DOE proposes that the CEI for circulator pumps with pressure controls be calculated with the unique weights and test points as shown in equation (4).

DOE requests comment on the proposed test method for circulator pumps with pressure controls, including whether DOE's interpretation of the new provisions in HI 41.5-2021 are accurate.

DOE is aware of some circulator pumps that are equipped with user-adjustable pressure controls such that the maximum and minimum head values on the control curve can be set to specifically match the system into which the pump is being installed. DOE's interpretation HI 41.5-2021 is that these types of controls are not addressed in the industry standard. To test such controls, DOE proposes that the maximum and minimum head values on user-adjustable pressure controls may be adjusted, if possible, to coincide with a maximum head value at the pump's BEP and a minimum head value equivalent to 20 percent of the BEP head value (consistent with the static offset of the proposed reference system curve). If only the maximum or minimum head value can be adjusted, DOE proposes that only the adjustable setting would be adjusted. In either case, DOE also proposes that the settings can be adjusted for testing only if they are adjustable by the user. DOE believes that this proposed methodology would result in the most representative performance of such adjustable controls by preventing the testing of specifically tuned control options that would not be representative of likely field performance. DOE notes that further adjustment to attain 100 percent of BEP head would be required.

In summary, for adjustable pressure controls with user-adjustable maximum and/or minimum head values, DOE proposes to allow one-time manual adjustment of the maximum and/or minimum control curve head values, as applicable, to coincide with a maximum head value at the pump's BEP and a minimum head value equivalent to 20 percent of the BEP head value with all subsequent test points taken along the adjusted control curve.

DOE requests comment on whether specific test provisions for circulator pumps equipped with user-adjustable pressure controls are needed, and if so, on the proposed provisions for such pumps.

The CPWG also identified a specific style of pressure control that adapts the control curve setting dynamically to the system in which it is installed; the CPWG referred to this style of pressure control as adaptive pressure controls. (Docket No. EERE-2016-BT-STD-0004, No. 72 at p. 45) As discussed in the introduction to section III.D, adaptive pressure controls are installed in similar applications as pressure controls, but can also be effective at reducing the head and flow provided in single-zone systems to adjust for typical pump oversizing. Also, due to the ability of adaptive pressure controls to measure and automatically adjust to the system requirements over time, adaptive pressure controls can result in optimized performance and energy use as compared to pressure-based controls. The CPWG noted that current adaptive pressure controls are learning-based controls that gradually adjust the pressure control set point over time based on the needs of the system. (Docket No. EERE-2016-BT-STD-0004, No. 72 at pp. 45-46) As such, the CPWG recommended separate test methods for pressure controls and adaptive pressure controls, noting the difference in operation and control logic between the control varieties. (Docket No. EERE-2016-BT-STD-0004, No. 73 at p. 176) Specifically, the CPWG discussed that since adaptive pressure controls gradually adjust the control curve over time to optimize the pressure control performance for the system in which it is installed, the test method specified for circulator pumps with pressure controls was not applicable because there is no fixed pressure control curve that can be evaluated. (Docket No. EERE-2016-BT-STD-0004, No. 72 at pp. 45-46) Instead, adaptive pressure controls have a control “area” that is defined by a minimum head value (H

auto_min

and H

set_min

), the maximum speed pump curve, and a maximum head value (H

set

), as depicted in in Figure III.2.

EP20DE21.005

Within the adaptive pressure control “area,” a multitude of different control curves may be selected based on the detected system head requirements. Therefore, the CPWG discussed the need to specify the “control curve” within an adaptive pressure control's control area along which such controls would be evaluated. (Docket No. EERE-2016-BT-STD-0004, No. 66 at pp. 95-98) For circulator pumps with adaptive pressure controls, the CPWG recommended that testing be conducted at the minimum thresholds for head based on manufacturer literature and through manual speed adjustment to achieve the test point flow rates with head values at or above the reference curve. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #9 at p. 7); 86 FR 24516, 24524.

For example, in Figure III.2, the CPWG recommended test method would result in minimum head thresholds of H

auto_min

at no flow conditions and H

set_min

at maximum flow, essentially the bottom edge of the adaptive pressure control area. However, DOE notes that the CPWG also specified that the test points could not be below the reference system curve (specified in section III.D.2), similar to pressure controls. Therefore, the CPWG discussed how adaptive pressure controls would be tested through manual speed adjustment to test points that are at or above the reference system curve or minimum head thresholds of the adaptive pressure control area, whichever is greater. (Docket No. EERE-2016-BT-STD-0004, No. 66 at pp. 95-98) This results in, for example, the test points denoted with the circles along the minimum pressure setting curve and the reference system curve in Figure III.2.

In response to the May 2021 RFI, DOE requested comment on the recommended test methods, test points, and weights for circulator pumps with adaptive pressure controls. 86 FR 24516, 24524.

In response, the CA IOUs encouraged DOE to incorporate representative field data for adaptive controls in a future test method, asserting there may be a minimal relationship between the preloaded defaults or reference curve and the eventual operating points of these devices in the field, in aggregate. The CA IOUs further recommended that DOE collaborate with industry to develop test procedures for these units to capture energy savings occurring in the overall marketplace. (CA IOUs, No. 116 at p. 7)

Grundfos commented that adaptive pressure control should not be an allowed test method in DOE's regulations. Grundfos stated that adaptive pressure controls cannot be tested in the way they operate. Grundfos commented that because the recommended test procedure would allow such pumps to be manually adjusted to the reference curve, a manufacturer could state that any product has adaptive pressure controls and test the product in a manner that is not aligned with actual performance. (Grundfos, No. 113 at p. 3)

DOE notes that the test method for such controls in HI 41.5-2021 (section

41.5.3.4.2 #4) is consistent with the CPWG recommendation. Section 41.5.3.4.2 #4 also allows for manual adjustment to achieve 100 percent BEP flow and head point at max speed.

In response to Grundfos, DOE notes that, as recommended by the CPWG, the proposed test procedure would require minimum head thresholds to be documented in the manufacturer literature associated with the given circulator pump model and be accessible based on the capabilities of the control with which the pump is distributed in commerce. That is, the minimum head thresholds may be manually set before testing the pump (similar to adjustable pressure controls), but such adjustment must be possible on the control with which the circulator pump is distributed in commerce and described in the manufacturer's literature. DOE believes this would ensure that the evaluated control threshold is representative of minimum head values that are realized in the field.

In response to the CA IOUs, DOE welcomes additional field data that could provide more information to support a future update of any finalized adaptive control test method. Based on the information currently available, DOE has tentatively determined that the adaptive pressure control test method recommended by the CPWG and proposed in this NOPR is reasonably designed to reflect energy use under typical operating conditions.

In summary, consistent with HI 41.5-2021, for adaptive pressure controls, DOE proposes to test at each test point at the minimum thresholds for head noted in the manufacturer literature or the head values specified along the reference system curve, whichever is greater. In addition, although not included in HI 41.5-2021, DOE also proposes that if the pump does not have a manual control mode available, the speed would be adjusted based on the pressure control mode with the lowest head at each load point, and if the selected pressure control results in a head value below the reference system curve, the pump would be throttled to achieve a head value at or above the reference system curve.

DOE requests comment on the proposed test methods for circulator pumps with adaptive pressure controls, and in particular on the proposed provisions not included in HI 41.5-2021, including for pumps without a manual control mode, whether throttling should be allowed to achieve head above the reference system curve, or instead head should be allowed below the reference system curve and adjusted back to the curve, as with other non-adaptive pressure controls. DOE also requests comment on the HI 41.5-2021 provision for manual adjustment to achieve 100 percent BEP flow and heat point at max speed, which is not included for other pressure controls.

4. Temperature Control

As previously discussed and as presented in the May 2021 RFI, temperature controls are controls that automatically adjust the speed of the variable speed drive in the pump continuously over the operating speed range to respond to a change in temperature of the operating fluid in the system. Typically, temperature controls are designed to achieve a fixed temperature differential between the supply and return lines and adjust the flow rate through the system by adjusting the speed to achieve the specified temperature differential. Similar to pressure controls, temperature controls are also designed primarily for hydronic heating applications. However, temperature controls may be installed in single- or multi-zone systems and will optimize the circulator pump's operating speed to provide the necessary flow rate based on the heat load in each zone. Unlike pressure controls, there are no minimum head requirements inherent to the temperature control, so temperature controls have the potential to use the least amount energy to serve a given load. 86 FR 24516, 24524.

The CPWG recommended that for circulator pumps distributed in commerce with temperature controls, PER

CIRC

should be calculated in the same way and with the same weights as for pressure controls, as shown in equation (4).(Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #6A at pp. 4-5); 86 FR 24516, 24524.

As temperature controls serve similar hydronic heating applications as pressure controls, the CPWG assigned the same weights, which are representative of the loads the circulator pump is serving. (Docket No. EERE-2016-BT-STD-0004, No. 70 at pp. 113-115) Specifically, for circulator pumps with temperature controls, the CPWG recommended weights of 0.05, 0.40, 0.40, and 0.15 at test points of 25, 50, 75, and 100 percent of BEP flow, respectively. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #7 at p.6)

Since circulator pumps with temperature controls are not limited by head requirements present in pressure controls and can match the required speed to meet the demand of the system, the head values at the specified flow rates of 25, 50, 75, and 100 percent of BEP flow are not dictated by the control curve logic. As such, the temperature control is able to achieve the exact head values at each flow rate described by the reference system curve (discussed in section III.D.2). Assuming the reference system curve represents a typical system, testing temperature controls along the reference system curve represents their likely performance because temperature controls have the ability to sense and respond precisely to the load on the system.

In addition to the test points, the CPWG also discussed how circulator pumps with temperature control should be controlled during testing. The CPWG discussed how testing temperature controls using conditioned water would be extremely burdensome and expensive. The CPWG discussed that providing less burdensome options for testing would represent a reasonable compromise to reduce the burden associated with testing temperature controls, while still resulting in representative energy performance ratings. (Docket No. EERE-2016-BT-STD-0004, No. 70 at pp. 282-288) Therefore, the CPWG recommended that circulator pumps with temperature controls be tested based on manual speed adjustment or with a simulated temperature signal to activate the temperature-based control to achieve the test point flow rates with a head at or above the reference curve. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #9 at p. 7); 86 FR 24516, 24524.

In the May 2021 RFI, DOE requested comment on the recommended test methods, test points, and weights for circulator pumps with temperature controls. Specifically, DOE requested comment on whether the technology or market for such controls has changed sufficiently since the term sheet to warrant a different approach. 86 FR 24516, 24524.

HI stated that it was not aware of any technical or market changes. (HI, No. 112 at p. 4) Grundfos stated that temperature control is a form of external control (

i.e.,

temperature sensor input to the controller), and that therefore, temperature control should be removed and included as part of external control for testing purposes. Grundfos suggested, however, that in this case manufacturers should be allowed to identify temperature control on their products. (Grundfos, No. 113 at p. 3-4)

DOE notes that the temperature control test method recommended by the CPWG is consistent with that in section 41.5.3.4.3 of HI 41.5-2021. In response to Grundfos, DOE notes that

the CPWG considered the category of external input signal controls as separate from temperature controls. Specifically, the CPWG noted that unlike pressure and temperature controls, for external input signal controls, the logic that defines how the circulator pump operating speed is selected in response to some measured variable (

e.g.,

temperature, pressure, or boiler fire rate) is not integral to the circulator as distributed in commerce. Instead, it is part of another control system, such as a building management system or a boiler control system. (Docket No. EERE-2016-BT-STD-0004, No. 72 at p. 83-84) DOE also notes that the test method recommended by the CPWG and in HI 41.5-2021 for circulator pumps with external input signal controls only and that cannot operate without an external signal control is the same as the test method for circulator pumps with temperature control. However, the CPWG recommended, and HI 41.5-2021 included, a different test method for external input signal controls with other control varieties or that can be operated without external input signal control. The reasons for this difference are discussed in section III.D.6. As such, DOE proposes to remain consistent with the CPWG recommendations and HI 41.5-2021 regarding specification of a temperature control test method.

DOE tentatively determines that the CPWG for temperature controls would allow for temperature controls to be tested in a way that captures the potential energy savings from this control variety without being overly burdensome for manufacturers to conduct. Therefore, DOE proposes to adopt the recommendations of the CPWG to test temperature controls based on manual speed adjustment or with simulated temperature signal to activate the temperature-based control to achieve the test point flow rates with a head at or above the reference system curve. Additionally, DOE proposes to use the weights and test points shown in equation (4) for circulator pumps distributed in commerce with temperature controls.

DOE requests comment on the proposed test methods, test points, and weights for circulator pumps with temperature controls.

5. Manual Speed Control

As discussed previously and as stated in the May 2021 RFI, manual speed controls are a control variety for which the speed of the pump is adjusted manually, typically to one of several pre-set speeds, by a dial or a control panel to fit the demand of the system within which it is installed. The CPWG discussed how circulator pumps installed with manual speed controls are typically only adjusted one time upon installation, if at all, and will operate at that set speed as if it were a single-speed circulator pump. As such, many manual speed control circulator pumps operate at full speed in the field, while a portion of them may be turned down to a medium or low speed to suit the needs of the systems. (Docket No. EERE-2016-BT-STD-0004, No. 65 at pp. 131-133); 86 FR 24516, 24524.

Therefore, the CPWG recommended to test circulator pumps with manual speed controls both: (1) Along the maximum speed circulator pump curve to achieve the test point flow rates for the max speed input power values, and (2) based on manual speed adjustment to the lowest speed setting that will achieve a head at or above the reference curve at the test point flow rate for the reduced speed input power values. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #9 at p. 7); 86 FR 24516, 24524.

To accomplish a single rating representative of the “average” energy use of a manual speed circulator, the CPWG recommended that for circulator pumps distributed in commerce with manual speed controls, the PER

CIRC

should be calculated as the weighted average of P

in,max

(the weighted average input power at specific load points across the maximum speed curve) and P

in,reduced

(the weighted average input power at specific load points at reduced speed), but recommended separate load points and speed factors, as shown in equations (5), (6), and (7):

EP20DE21.006

Where:

PER

CIRC

= circulator pump energy rating (hp);

max

= speed factor weight of 0.75;

in_max

= weighted average input power at maximum rotating speed of the circulator (hp), as specified in equation (6);

reduced

= speed factor weight of 0.25; and

in_reduced

= weighted average input power at reduced rotating speed of the circulator (hp), as specified in equation (7).

EP20DE21.007

Where:

in_max

= weighted average input power at maximum speed of the circulator (hp);

i_max

= 0.25;

in,i_max

= power input to the driver at maximum rotating speed of the circulator pump at each test point i (hp); and

i = test point(s), defined as 25, 50, 75, and 100 percent of the flow at BEP.

EP20DE21.008

Where:

in_reduced

= weighted average input power at reduced speeds of the circulator (hp);

i_reduced

= 0.3333;

in,i_reduced

= power input to the driver at reduced rotating speed of the circulator pump at each test point i (hp); and

i = test point(s), defined as 25, 50, and 75 percent of the flow at BEP of max speed and head values at or above the reference curve.

(Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #6B and 7 at pp. 5-6); 86 FR 24516, 24524-24525.

The CPWG specified the speed factor for maximum speed (z

max

) and reduced speed (z

reduced

) to represent the likelihood that the circulator pump would operate at maximum versus reduced speed, or the likelihood that an installer would turn down the speed of the circulator pump in the field. The CPWG concluded that about 75 percent of the time, circulator pumps with manual speed controls are operated at maximum speed. (Docket No. EERE-2016-BT-STD-0004, No. 71 at p. 377) Therefore, the CPWG recommended that the speed factor for maximum speed (z

max

) should be 0.75 and the speed factor for reduced speed (z

reduced

) should be 0.25. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #7 at p. 6)

The CPWG concluded that when a circulator pump with manual speed control is installed and set to maximum speed, it operates like a single-speed pump and should receive the same weighting as a circulator pump with no controls for the maximum speed weights, represented as w

i_max

in equation (6). (Docket No. EERE-2016-BT-STD-0004, No. 70 at pp. 183-184) For the weights associated with reduced speeds using manual speed controls, the CPWG concluded that equal weighting of 0.3333 for each of the reduced speed points of 25, 50, and 75 percent of BEP flow at maximum speed would best represent the “average” performance of the manual speed circulator pump at reduced speed, represented as w

i_reduced

in equation (7). (Docket No. EERE-2016-BT-STD-0004, No. 71 at pp. 433-437)

DOE requested comment on the CPWG-recommended test method and the unique test points, weights, and speed factors for circulator pumps distributed in commerce with manual speed controls. Specifically, DOE requested comment on whether the technology or market for such controls has changed sufficiently since the term sheet to warrant a different approach. 86 FR 24516, 24525.

Grundfos recommended that DOE remove manual speed control from the regulation, stating that these pumps should be tested as circulator pumps with no control. (Grundfos, No. 113 at p. 4) Grundfos asserted that these devices are not manually controlled in real application and are simply set at a desired speed, violating the intention of energy savings and the intention of the ability to reduce speed during operation. (Grundfos, No. 113 at p. 3)

DOE notes that the CPWG specifically addressed the issues raised by Grundfos in discussing how the test points at maximum speed were designed to represent the performance at maximum speed and account for operation at maximum speed the majority of the time, while the test points at reduced speed allowed some “credit” for being able to reduce speed. (Docket No. EERE-2016-BT-STD-0004, No. 70 at p. 201-202) As stated previously, the CPWG concluded that about 75 percent of the time, circulator pumps with manual speed controls are operated at maximum speed, as reflected in its recommended procedure. (Docket No. EERE-2016-BT-STD-0004, No. 71 at p. 377) For these reasons, DOE proposes to include manual speed control as a test method in the circulator pump test procedure.

HI recommended using the modified testing methodology in HI 41.5-2021 section 41.5.3.4.5 for manual speed control. Specifically, HI believes the minimum system control head should be the value at 25 percent BEP on the reference curve for the manual control (and pressure control) method. HI described its findings that intersecting the pump curve at BEP and requiring the control mode to be above the reference curve was too limiting. HI asserted that this did not represent the controls available in the market, nor did it properly demonstrate the benefit of the onboard controls. HI commented that section 41.5.3.4.5 allows controls to be rated below the reference curve with power correction back to the reference curve. (HI, No. 112 at 5) HI stated that this change eliminates the need for all control curves to exist above the reference curve, allowing for a better presentation of control curves used in the market and for the circulator pump CEI values to better represent a pump's capabilities. (HI, No. 112 at p. 2)

The Advocates supported the update in HI 41.5-2021 that includes a modification to correct for test data below the reference curve, stating that this improves representativeness for many circulator pump models. (Advocates, No. 114 at pp. 1-2) As stated previously, NEEA generally supported adopting HI 41.5-2021 as the test method for pumps, which incorporates these modifications discussed by HI and the Advocates. (NEEA, No. 115 at p. 4)

DOE tentatively determines the CPWG recommendations regarding the test method for manual speed control circulator pumps are appropriate and representative, as they account for the likelihood that a circulator pump with manual speed controls will be installed and operated at maximum speed, but also accounts for the potential energy savings associated with reduced speed operation. However, DOE understands that through stakeholders' experience with using this test method, certain changes to the term sheet recommendations would improve representativeness by capturing the benefit of onboard controls available in the market. Therefore, DOE proposes to test circulator pumps with manual speed controls consistent with the provisions in section 41.5.3.4.5 of HI 41.5-2021, as follows: (1) The tested control must produce head equal to or greater than 25 percent of BEP head at a minimum of one test point (HI 41.5-2021 section 41.5.3.4.5 #2a), and (2) the control curve setting being evaluated must achieve 100 percent BEP flow of the reference curve (HI 41.5-2021 section 41.5.3.4.5 #2b). DOE also proposes that the CER be calculated as the weighted average of P

in,max

and P

in,reduced

, as shown in equations (5), (6), and (7), but with removal of the requirements for test points to be at or above the reference curve. DOE notes that HI 41.5-2021 section 41.5.3.4.5 #3 still retains that provision, which DOE assumes to be an error based on HI's comments and recommendations in response to the May 2020 RFI.

DOE also notes that the introductory text of HI 41.5-2021 section 41.5.3.4.5 specifies that the test method applies to manual speed control, which can be operated without an external input signal, but DOE also believes this provision is superfluous as manual speed controls by definition do not require an external input signal.

DOE requests comment on the proposed test method and the unique test points, weights, and speed factors for circulator pumps distributed in commerce with manual speed controls.

6. External Input Signal Control

As discussed previously and as stated in the May 2021 RFI, the final control variety considered by the CPWG was external input signal controls. External input signal controls are controls in which the device that responds to the stimulus, or the primary control logic, is external to the circulator pump. Unlike pressure and temperature controls, the logic that defines how the circulator pump operating speed is selected in response to some measured variable (

e.g.,

temperature, pressure, or boiler fire rate) is not part of the circulator, as distributed in commerce. Instead, it is part of another control system, such as a building management system or a boiler control system. (Docket No. EERE-2016-BT-STD-0004, No. 72 at p. 84) 86 FR 24516, 24525.

For circulator pumps that have only an external input signal control, the CPWG recommended testing along the reference control curve to achieve the test point flow rates with a head at or above the reference system curve with the same weights as temperature and pressure controls, as shown in equation (4). The CPWG recommended that, in order to ensure that the rating was representative of the performance of such pumps, the external input signal control must be the only control mode that can be used with the circulator pump, and the circulator pump must not be able to operate without an external input signal. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #9 at pp. 7-8); 86 FR 24516, 24525.

The CPWG asserted that if external input signal control is one of multiple options available on a circulator pump, or the pump is able to operate without an external input signal, it is less likely that the external input signal control option is going to be utilized since it requires external logic and equipment in order to operate properly. (Docket No. EERE-2016-BT-STD-0004, No. 72 at pp. 216-218, 229). The CPWG recommended testing circulator pumps with external input signal controls similar to manual speed controls. (Docket No. EERE-2016-BT-STD-0004, No. 47 at p. 480) Specifically, the CPWG recommended testing a circulator pump sold with external input signal controls and another control variety with a simulated signal both: (1) Along the maximum speed circulator pump curve to achieve the test point flow rates for the max speed input power values and (2) with speed adjustment using a simulated signal to the lowest speed setting that will achieve a head at or above the reference curve at the test point flow rates for the reduced speed input power values. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #9 at pp. 7-8); 86 FR 24516, 24525.

As such, the CPWG recommended that for circulator pumps distributed in commerce with external input signal controls among other control varieties, the PER

CIRC

should be calculated as the weighted average of P

in,max

(the weighted average input power at specific load points across the maximum speed curve) and P

in,reduced

(the weighted average input power at specific load points at reduced speed), similar to circulator pumps with manual speed control, as shown in equation (8), (9), and (10):

EP20DE21.009

Where:

PER

CIRC

= circulator pump energy rating (hp);

max

= speed factor weight of 0.30;

in_max

= weighted average input power at maximum rotating speed of the circulator pump (hp);

reduced

= weighted average input power at reduced rotating speed of the circulator (hp).

EP20DE21.010

Where:

in_max

= weighted average input power at maximum speed of the circulator (hp);

i_max

= 0.25;

in.i_max

= power input to the driver at maximum rotating speed of the circulator pump at each test point i (hp);and

i = test point(s), defined as 25, 50, 75, and 100 percent of the flow at BEP.

EP20DE21.011

Where:

in_reduced

= weighted average input power at reduced speeds of the circulator pump (hp);

i_reduced

= 0.3333;

in.i_reduced

= power input to the driver at reduced rotating speed of the circulator pump at each test point i (hp); and

i = test point(s), defined as 25, 50, 75 percent of the flow at BEP of max speed and head values at or above the reference curve.

(Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendations #6B and #7 at pp. 5-6); 86 FR 24516, 24525-24526.

The CPWG recommended the speed factors of 0.30 at maximum speed and 0.70 at reduced speed in order to produce a rating on an equivalent basis as that of a circulator pump with a typical differential pressure control. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #7 at p. 6). In addition, these speed factors would represent the likelihood that a circulator pump with an external input signal control is selected to operate with that external input signal control, and whether the signal it receives results in the circulator pump reducing speed. 86 FR 24516, 24526.

DOE requested comment on the CPWG-recommended test method for circulator pumps distributed in commerce with only external input signal controls, as well as for those distributed in commerce with external input signal controls in addition to other control varieties. Specifically, DOE requested comment on whether the technology or market for such controls has changed sufficiently since the term sheet to warrant a different approach. 86 FR 24516, 24526.

HI stated that it is not aware of any technical or market changes. (HI, No. 112 at p. 5). As stated previously, Grundfos recommended that external input and temperature controls be tested in the same way, with labeling to differentiate these control methods for consumer purposes. Grundfos stated that the functional characteristics are the same between both methods. (Grundfos, No. 113 at p. 4) DOE addressed this comment in section III.D.4.

DOE notes that the CPWG-recommended test method for circulator pumps distributed in commerce with only external input signal controls is generally consistent with that found in section 41.5.3.4.4 of HI 41.5-2021. HI 41.5-2021 contains additional specifications not found in CPWG recommendations that, for circulator pumps with only external input signal control, manual speed adjustment or simulated external input signal can be used to achieve the relevant flow rates (section 41.5.3.4.4.1 #2). DOE also notes that the CPWG-recommended test method for circulator pumps distributed in commerce with external input signal controls in addition to other control varieties is mostly consistent with that found in section 41.5.3.4.4.2 of HI 41.5-2021. However, where the CPWG recommendations specify testing using a simulated signal, whereas HI 41.5-2021 specifies testing using manual speed adjustment (section 41.4.3.4.4.2 #2). In addition, HI 41.5-2021 does not specify using the lowest speed setting that results in a head value at or above the reference system curve; rather, it specifies to manually adjust the speed to achieve the specified flow rates with head at or above the reference control curve (section 41.4.3.4.4.2 #2).

DOE proposes to specify a test method for circulator pumps sold only with external input signal control and that cannot operate without an external input signal. Specifically, DOE proposes to test along the reference system curve to achieve the test point flow rates with a head at or above the reference curve, and that CEI would be calculated as shown in equation (2). DOE also proposes to test circulator pumps sold with external input signal controls along with other controls, or which can be operated without an external input signal control, both: (1) Along the maximum speed circulator pump curve to achieve the test point flow rates for the max speed input power values and (2) with speed adjustment that will achieve a head at or above the reference system curve at the test point flow rates for the reduced speed input power values. DOE proposes that in either case, either manual speed adjustment or simulated external input signal can be used to achieve the relevant flow rates. DOE is not proposing that the speed adjustment include the “lowest speed setting” that results in a head value at or above the reference system curve; however, DOE addresses this issue in its enforcement provision proposals (section III.F.2). Finally, DOE proposes that the CEI should be calculated as the weighted average of P

in,max

and P

in,reduced

, as shown in equations (8), (9), and (10).

Based on consideration of the CPWG recommendations and stakeholder comments, DOE tentatively concludes that the proposed test provisions for circulator pumps distributed in commerce with external input signal controls would produce representative results for such equipment and would not be unduly burdensome to conduct.

DOE requests comment on the proposed test method and the unique test points, weights, and speed factors for circulator pumps distributed in commerce with external input signal controls. In particular, DOE requests comment on whether manual speed adjustment and/or simulated external input signal are appropriate for testing circulator pumps with external input signal only, as well as circulator pumps with external input signal in addition to other control varieties. DOE also seeks comment on whether it is necessary to reference the “lowest speed setting” when determining the appropriate test points. Finally, DOE seeks comment on whether the test points and weights for circulator pumps distributed in commerce with external input signal control in addition to other control varieties are appropriately reflective of their energy consumption in the field relative to other control varieties.

7. No Controls

As discussed previously and as stated in the May 2021 RFI, for circulator pumps with no controls,

the CPWG recommended testing the pump along the maximum speed circulator pump curve to achieve the test point flow rates of 25, 50, 75, and 100 percent of BEP flow. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #9 at p. 7); 86 FR 24516, 24526.

In this document, circulator pumps with no controls are also inclusive of other potential control varieties that are not one of the specifically identified control varieties.

The CPWG also recommended that for circulator pumps distributed in commerce without manual speed controls, pressure controls, temperature controls or external input signal controls, PER

CIRC

should be calculated with the unique weights and test points as shown in equation (11):

EP20DE21.012

Where:

PER

CIRC

= circulator pump energy rating (hp);

= 0.25;

in,i

= power input to the driver at each test point i (hp); and

i = test point(s), defined as 25, 50, 75, and 100 percent of the flow at BEP.

(Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #6A at pp. 4-5); 86 FR 24516, 24526.

The CPWG recommended the 0.25 weights at each test point (

i.e.,

25, 50, 75, and 100 percent of the flow at BEP) in order to account for the variety of systems and operating points a single-speed circulator pump may encounter. (Docket No. EERE-2016-BT-STD-0004, No. 70 at pp. 172-173); 86 FR 24516, 24526.

DOE requested comment on the CPWG-recommended test methods, test points, and weights for circulator pumps with no controls. 86 FR 24516, 24526.

HI stated that it is not aware of any changes; however, HI recommended that DOE change the term “no controls” to “full speed” to ensure market clarity and align with common terminology. (HI, No. 112 at p. 5) Grundfos also recommended that DOE change this name to Full Speed to clarify the intent of the testing and make it clear that this test method is only to define the baseline circulator pump CEI and is not a qualified control method for rating a circulator pump by itself. (Grundfos, No. 113 at p. 4)

DOE notes that the CPWG recommended test method for circulator pumps with no controls is consistent with that in section 41.5.3.4.1 of HI 41.5-2021 (“Determination of CER—Full Speed”). In response to Grundfos, DOE notes that the “no controls” test method as recommended by the CPWG and as proposed in this NOPR is a test method for rating a pump that does not have any of the other controls for which a test method is specified. DOE proposes to define this test method separately from the calculation to determine the CER

STD

. In response to HI, DOE understands that as part of the HI Energy Rating program, manufacturers are using the no controls test to determine the most consumptive rating for their pumps. Therefore, in order to provide regulatory clarity about which pumps must be rated using the “no controls” test method, but also accommodate the option for any pump to be rated using the “no controls” test method, DOE proposes to refer to this test method in the regulatory text as the test method for circulator pumps without external signal, manual, pressure, or temperature controls (

i.e.,

full speed test). DOE also proposes additional language in the scope section regarding this clarification.

Consistent with the recommendations of the CPWG, DOE proposes to test circulator pumps without external input signal, manual, pressure, or temperature controls along the maximum speed circulator pump curve to achieve the test point flow rates. DOE agrees that since these circulator pumps with no controls are single-speed controls and only have a single speed, testing at maximum speed is representative of the typical operation of circulator pumps with no controls. Additionally, DOE proposes to use equation (11) with the unique weights and test points to test circulator pumps with no controls, with nomenclature updated from PER

CIRC

to CER.

DOE requests comment on the proposed test method for circulator pumps distributed in commerce with no controls.

E. Determination of Circulator Pump Performance

As stated in the May 2021 RFI, as part of the September 2016 CPWG Recommendations, the CPWG recommended that all test points be tested on a wire-to-water basis, in accordance with HI 40.6-2014, with minor modifications. The CPWG also recommended that if an updated version of HI 40.6 is published prior to publication of the test procedure final rule, DOE should review and incorporate the updated version. (Docket No. EERE-2016-BT-STD-0004, No. 58, Recommendation #10 at p. 8-9); 86 FR 24516, 24526. The CPWG also recommended several modifications related to frequency of data collection, BEP speed, electrical measurement equipment, relevant parameters at specific load points, power supply characteristics, and rounding of values for calculating and reporting purposes. (Docket No. EERE-2016-BT-STD-0004, No. 58 Recommendation #10 at pp. 8-9)

Two updated versions of HI 40.6—HI 40.6-2016 and HI 40.6-2021—have been published since the CPWG meetings concluded. Section III.E.1 discusses HI 40.6-2021, the industry standard, which DOE proposes to incorporate by reference, for measuring the performance of circulator pumps, noting the changes made from the previous version of HI 40.6-2014. DOE believes that it is necessary to make several exceptions, modifications, and additions to this test procedure to ensure accuracy and repeatability of test measurements (sections III.E.2.a through III.E.2.c) and that the test method produces results that reflect energy efficiency or energy use during a representative average use cycle without being unduly burdensome to conduct. Additionally, DOE proposes specific procedures for calculating the CEI and rounding of values to ensure that the resultant ratings are determined in a consistent manner (section III.E.2.d).

1. Incorporation by Reference of HI 40.6-2021

As stated in the May 2021 RFI, in 2016, HI published an updated industry standard, HI 40.6-2016, “Methods for Rotodynamic Pump Efficiency Testing” (“HI 40.6-2016”). 86 FR 24516, 24526. This update aligned the definitions and procedures described in HI Standard 40.6 with the DOE test procedure for pumps published in the January 2016 TP final rule. Appendix A to subpart Y to 10 CFR part 431. In the September 2020 Early Assessment RFI for pumps, DOE requested comment on the potential effect of incorporating HI 40.6-2016 by reference as the DOE test procedure for pumps. 85 FR 60734, 60737. Grundfos, NEEA, and HI commented that HI expects to publish another standard update in 2021 and urged DOE to incorporate by reference HI 40.6-2021 rather than HI 40.6-2016 (Grundfos, Docket No. EERE-2020-BT-TP-0032, No. 07 at p. 2; NEEA, Docket No. EERE-2020-BT-TP-0032, No. 08 at p. 6; HI, Docket No. EERE-2020-BT-TP-0032, No. 06 at pp. 1, 3). HI specified that HI 40.6-2016 included updates to match DOE's test procedure for pumps, and that HI 40.6-2021 would further include editorial revisions and would add circulator pump testing, and also would not impact measured values, burden, or representativeness. (HI,

Docket No. EERE-2020-BT-TP-0032, No.06 at p. 3); 86 FR 24516, 24526. At the time of the May 2021 RFI development, HI 40.6-2021 was not yet published.

In the May 2021 RFI, DOE sought comment and feedback on whether HI 40.6-2016 or HI 40.6-2021 is an appropriate test method for conducting wire-to-water testing of circulator pumps, as recommended by the CPWG. In addition, DOE sought comment on whether the modifications in HI 40.6-2016 and/or HI 40.6-2021 adequately capture the CPWG recommended modifications in Recommendation #10. 86 FR 24516, 24526.

HI stated that HI 40.6-2021 should be incorporated by reference and that the 2021 edition modified the 2016 version only to add specific testing requirements for circulator pumps. (HI, No. 112 at p. 5) Grundfos also stated that DOE should accept HI 40.6-2021 for incorporation into the regulation and that it provides appropriate testing methods as defined by the CPWG. Grundfos also stated that there were some specific deviations from Recommendation #10 with respect to “Relevant Parameters at Specific Load Points.” Specifically, Grundfos stated that while implementing the industry rating program, manufacturers identified that requiring all tested flow points to be within ±10 percent of the reference curve was not feasible for pressure control, especially when operating at constant pressure at heads below the BEP head. Grundfos further stated that the HI committee made modifications to this recommendation in HI 41.5 that preserve the integrity of the calculation of efficiency and allow for these products to be properly tested and labeled. (Grundfos, No. 113 at p. 4-5)

NEEA, the Advocates, and the CA IOUs recommended that DOE adopt HI 41.5-2021 as the test method for circulator pumps. (NEEA, No. 115 at p. 4, Advocates, No. 114 at p. 1, CA IOUs, No. 116 at p. 2) The Advocates stated that an update to the program guideline, HI 41.5-2021, includes a modification to correct for test data below the reference curve and that they understand that this change improves representativeness for many circulator pump models and is consistent with the intent of the term sheets. They also stated that HI 41.5-2021 includes additional minor modifications to improve accuracy and clarity. (Advocates, No. 114 at pp. 1-2) Similarly, NEEA stated that HI 41.5-2021 includes slight modifications from the original term sheet for testing with pressure controls that operate below the reference curve, and that the modifications provide more representative values. (NEEA, No. 115 at p.4)

China made several requests related to specific provisions in the HI 40.6 test procedure. China commented that DOE should present the information related to pump test acceptance grades and corresponding tolerance, referring to Table 8 of part 4.4.1 and the provision of part 4.4.2 in ISO 9906:2012. China recommended that DOE clarify the scientific basis of the selection of the 7 test points which are 40, 60, 75, 90, 100 and 120 percent of the flow rate at the expected BEP. China further recommended that DOE clarify the efficiency testing method for integrated design products of electric pumps. (China, No. 111 at p. 3)

Since publication of the May 2021 RFI, HI has published HI 40.6-2021. DOE has reviewed HI 40.6-2021 and determined that the test methods contained within HI 40.6-2021 are generally consistent with HI 40.6-2014 and are sufficiently specific and reasonably designed to produce test results to determine a CEI that is representative of an average use cycle of applicable circulator pumps. Specifically, Table 40.6.2 of HI 40.6-2021, like HI 40.6-2014, defines and explains how to calculate driver power input,

volume per unit time,

pump total head,

and other relevant quantities, which are essential to determining the metric.

The term “driver or control power input” in HI 40.6-2021 is defined as “the power input to the driver or control;” in this NOPR, DOE refers to “driver power input” as the power to either the motor or the controls, if present.

The term “volume per unit time” in HI 40.6-2021 is defined as “. . . the volume rate of flow in any given section . . . Also referred to as

flow, flow rate,

and

rate of flow.

”

The term “pump total head” is defined in HI 40.6-2021 as “the algebraic difference between the outlet total head and the inlet total head” and is used synonymously with the term “head” in this document.

HI 40.6-2021 also contains appropriate specifications regarding the scope of pumps covered by the test method, standard rating conditions, equipment specifications, uncertainty calculations, and tolerances. The electrical measurement specification and associated equipment specifications in section C.4.3 of HI 40.6-2021 contain the relevant measurement specifications for certain non-energy metrics (

i.e.,

true RMS current, true RMS voltage, and real power) that manufacturers may choose to make representations about for each rated circulator pump. These specifications also describe the relevant measurements used in the calculation of true power factor (“PF”) at each applicable load point for each circulator pump control variety, a non-energy metric manufacturers may wish to use to make representations. In addition, HI 40.6-2021 contains a new appendix E with specific test instructions for circulator pumps. DOE notes that section 41.5.3.1 of HI 41.5-2021 references Appendix E of HI 40.6-2021 as the test standard that governs measurements of all test points in the standard. DOE has reviewed HI 40.6-2021 with respect to the minor modifications listed by the CPWG in Recommendation #10. DOE has found that recommendations regarding frequency of data collection are included in section 40.6.5.5.1, and recommendations regarding electrical measurement equipment and power supply characteristics are included in section C.3.4.1 and Table 40.6.3.2.3. The recommendation regarding BEP speed—specifically, to test at max speed with no adjustment to nominal—is addressed in Appendix E of HI 40.6-2021, which excludes sections 40.6.5.5.2, 40.6.6.1, and 40.6.6.1.1, dealing with the specified speed of rotation and translation to that specified speed. The recommendations for relevant parameters at specific load points have been addressed in Appendix E of HI 40.6-2021 as well as HI 41.5-2021, with some modifications. These provisions are discussed in section III.E.2.c of this NOPR. The recommendations for rounding values for calculation and reporting purposes are not addressed in HI 40.6-2021 or HI 41.5-2021; DOE discusses these provisions in section III.E.2.d of this document.

In response to NEEA, the Advocates, and the CA IOUs, DOE does not propose to incorporate by reference HI 41.5-2021 as the test method for circulator pumps, as noted in section II. DOE instead proposes to rely on the industry test standard, HI 40.6-2021, with additional provisions in regulatory text consistent with HI 41.5-2021.

In response to China, with respect to section 40.6.4.4 of HI 40.6-2021, DOE notes that HI 40.6-2021 provides methods to determine energy efficiency as opposed to guaranteeing certain performance (

e.g.,

pump head, flow, power, or efficiency) in a particular application. As such, acceptance grades are not relevant. However, HI 40.6-2021 does define permissible fluctuations in Table 40.6.3.2.2. With respect to the test points in 40.6.5.5.1, DOE discusses these further in section III.E.2.c of this document.

With respect to section 40.6.3 of HI 40.6-2021 and the efficiency testing method of integrated design products of

electric pumps, DOE is not clear what is meant by “integrated design products.” However, section 40.6.4.4 of HI 40.6-2021 discusses determination of pump overall efficiency of a motor pump unit or a complete pump (

i.e.,

bare pump, mechanical equipment, driver and drive coupled together and treated as an integral unit). In addition, Appendix E of HI 40.6-2021 specifies that for circulator pumps, all power measurements must be measured inclusive of the driver, or driver and controls when appl

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