CHAPTER 4. SCREENING ANALYSIS

TABLE OF CONTENTS

4.1 INTRODUCTION............................................................................................................4­1

4.2 TECHNOLOGIES THAT DO NOT AFFECT CALCULATED DAILY

ENERGY CONSUMPTION........................................................................................................4­2

4.2.1 Higher­Efficiency Expansion Valves...................................................................4­2

4.2.2 Condenser Fan Motor Controllers........................................................................4­3

4.2.3 Anti­Sweat Heater Controllers.............................................................................4­3

4.2.4 Liquid­Suction Heat Exchangers .........................................................................4­3

4.3 SCREENED­OUT TECHNOLOGIES ............................................................................4­3

4.3.1 Improved Air Curtains .........................................................................................4­4

4.3.2 Thermoacoustic Refrigeration..............................................................................4­4

4.3.3 Magnetic Refrigeration ........................................................................................4­4

4.3.4 EHD Enhanced Heat Transfer..............................................................................4­5

4.3.5 Copper Rotor Motors ...........................................................................................4­5

4.4 REMAINING TECHNOLOGIES ...................................................................................4­5

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 EE-2006-STD-0126 COMMENT 11.2
CHAPTER 4. SCREENING ANALYSIS

4.1 INTRODUCTION

This document addresses the screening analysis that the U.S. Department of

Energy (DOE) carried out in support of the ongoing energy conservation standards

rulemakings for commercial refrigeration equipment, including commercial ice­cream

freezers; self­contained commercial refrigerators, commercial freezers, and commercial

refrigerator­freezers without doors; and remote­condensing commercial refrigerators,

commercial freezers, and commercial refrigerator­freezers. These rulemakings are

mandated by the Energy Policy Act of 2005 (EPACT 2005), and are effective for

equipment manufactured on or after January 1, 2012.

In the market and technology assessment (chapter 3), DOE presented an initial list

of technologies that can be used to reduce the energy consumption of commercial

refrigeration equipment. The goal of the screening analysis is to screen out technologies

that will not be considered further in the rulemaking analyses. DOE understands that

some of the technologies considered in chapter 3 can reduce annual energy consumption

under real­world conditions, but may not reduce calculated daily energy consumption

(CDEC), as measured according to the American National Standards Institute/American

Society of Heating, Refrigerating and Air­Conditioning Engineers (ANSI/ASHRAE)

Standard 72­2005, Method of Testing Commercial Refrigerators and Freezers, test

procedure. Therefore, DOE removed from consideration those technologies that have no

effect or do not reduce CDEC. The list of remaining technologies was evaluated

according to the screening criteria set forth in the Energy Policy and Conservation Act

(EPCA). (42 U.S.C. 6311­6317)

Section 325(o) EPCA establishes criteria for prescribing new or amended

standards that are designed to achieve the maximum improvement in energy efficiency.

Further, EPCA directs the Secretary of Energy to determine whether a standard is

technologically feasible and economically justified. (42 U.S.C. 6295(o)(2)(A), as

directed by 42 U.S.C. 6316(a)(1)­(3). In addition, EPCA establishes guidelines for

determining whether a standard is economically justified. (42 U.S.C. 6295(o)(2)(B)) In

view of the EPCA requirements for determining whether a standard is technologically

feasible and economically justified, appendix A to subpart C of Title 10, Code of Federal

Regulations, Part 430 (10 CFR Part 430), “Procedures, Interpretations, and Policies for

Consideration of New or Revised Energy Conservation Standards for Consumer

Products” (the Process Rule), sets forth procedures to guide DOE in its consideration and

promulgation of new or revised efficiency standards. These procedures elaborate on the

statutory criteria provided in 42 U.S.C. 6295(o) and, in part, eliminate problematic

technologies early in the process of prescribing or amending an energy efficiency

standard. In particular, sections 4(b)(4) and 5(b) of the Process Rule provide guidance to

DOE for making a determination whether to eliminate from consideration any technology

that presents unacceptable problems with respect to the following criteria:

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Technological feasibility. Technologies incorporated in commercial equipment

or in working prototypes will be considered technologically feasible.

Practicability to manufacture, install, and service. If mass production of a

technology in commercial equipment and reliable installation and servicing of the

technology could be achieved on the scale necessary to serve the relevant market at the

time of the effective date of the standard, then that technology will be considered

practicable to manufacture, install and service.

Impacts on equipment utility or equipment availability. If a technology is

determined to have significant adverse impact on the utility of the equipment to

significant subgroups of consumers, or result in the unavailability of any covered

equipment type with performance characteristics (including reliability), features, sizes,

capacities, and volumes that are substantially the same as equipment generally available

in the United States at the time, it will not be considered further.

Adverse impacts on health or safety. If it is determined that a technology will

have significant adverse impacts on health or safety, it will not be considered further.

In sum, if DOE determines that a technology, or a combination of technologies,

has unacceptable effects on the policies stated in section 5(b) of the Process Rule, it will

be eliminated from consideration. If a particular technology fails to meet one or more of

the four criteria, it will be screened out. The reasons for eliminating any technology are

documented in section 4.3.

4.2 TECHNOLOGIES THAT DO NOT AFFECT CALCULATED DAILY

ENERGY CONSUMPTION

DOE understands that some of the technologies identified in the market and

technology assessment can reduce annual energy consumption of equipment in real­world

conditions, but have no effect or do not reduce CDEC. Because the ANSI/ASHRAE

Standard 72­2005 test procedure calls for a steady­state test, technologies that only

reduce energy use under transient conditions will not affect the measured CDEC. Since

CDEC is the measure of energy consumption used in the present rulemaking analyses,

technologies that have no effect or do not reduce CDEC are not beneficial in the

rulemaking context. Therefore, DOE removed the following technologies from

consideration: higher­efficiency expansion valves, condenser fan motor controllers, antisweat heater controllers, and liquid­suction heat exchangers (LSHXs).

4.2.1 Higher­Efficiency Expansion Valves

Higher­efficiency expansion valves can reduce the annual energy consumption of

commercial refrigeration equipment by adapting to varying loads and ambient conditions.

Because ANSI/ASHRAE Standard 72­2005 is a steady­state test (i.e., there are no

changes in refrigerated­product loading or ambient conditions), there is no opportunity

for higher­efficiency expansion valves to reduce CDEC. Consequently, DOE did not

consider higher­efficiency expansion valves in the engineering analysis.

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4.2.2 Condenser Fan Motor Controllers

Condenser fan motor controllers can adapt condenser operation to changing

ambient temperatures (effectively by creating floating head pressure), and thereby reduce

annual energy consumption of self­contained commercial refrigeration equipment.

However, because testing under the ANSI/ASHRAE Standard 72­2005 test procedure is

conducted at a constant temperature, there is no opportunity to account for the adaptive

technology of a condenser fan motor controller to reduce CDEC. Therefore, DOE did not

consider condenser fan motor controllers in the engineering analysis.

4.2.3 Anti­Sweat Heater Controllers

A commercial refrigeration equipment manufacturer typically sizes anti­sweat

heaters according to the maximum ambient temperature and humidity of a particular

operating environment. It is therefore incumbent upon the end­user to effectively

maintain that environment to prevent condensation (fog) from forming on surfaces such

as display case glass. Anti­sweat heater controllers modulate the operation of anti­sweat

heaters by reducing anti­sweat heater power when humidity is low. Anti­sweat heater

controllers operate most effectively when the dew point cannot be constantly maintained.

Because testing under the ANSI/ASHRAE Standard 72­2005 test procedure is conducted

at a constant temperature and humidity, there is no opportunity to account for the

adaptive technology of an anti­sweat heater controller to reduce CDEC. Therefore, DOE

did not consider anti­sweat heater controllers in the engineering analysis.

4.2.4 Liquid­Suction Heat Exchangers

A LSHX is an indirect liquid­to­vapor heat transfer device that is used to

evaporate any residual liquid refrigerant that may remain in the evaporator discharge line,

and thereby minimize the risk of liquid refrigerant carrying over to the compressor

suction. In general, LSHXs are installed in refrigeration systems with the intent of

ensuring proper system operation and increasing system performance. However, the

combination of refrigerant type, operating temperature, ambient conditions, and other

factors determines whether an LSHX will create an increase or decrease in CDEC as

measured by the ANSI/ASHRAE Standard 72­2005 test procedure. Because an LSHX

does not consistently reduce CDEC, DOE did not consider this technology in the

engineering analysis.

4.3 SCREENED­OUT TECHNOLOGIES

This section addresses the technologies that DOE screened out because they did

not meet the requirements of sections 4(a) and 5(b) of the Process Rule. DOE considered

the following four factors: (1) technological feasibility; (2) practicability to manufacture,

install, and service; (3) adverse impacts on equipment utility to consumers; and (4)

adverse impacts on health or safety. The technologies that were screened out are: air

curtain design, thermoacoustic refrigeration, magnetic refrigeration, electrohydrodynamic (EHD) heat exchangers, and copper rotor motors.

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4.3.1 Improved Air Curtains

An air curtain is a fan­powered device that creates a moving wall (curtain) of air,

which separates two spaces of different temperatures. It is used to prevent the loss of

refrigerated air from, for example, the display area of semi­vertical commercial

refrigerator and prevent the entry of warm ambient air. DOE understands that improved

air curtains are in the research stage and, therefore, believes that it would not be

practicable to manufacture, install, and service this technology on the scale necessary to

serve the relevant market at the time of the effective date of the standard. Also, because

this technology is in the research stage, DOE cannot assess whether improved air curtains

will have any adverse impacts on utility to significant subgroups of consumers, result in

the unavailability of any type of commercial refrigeration equipment, or present any

significant adverse impacts on health or safety. DOE, therefore, screened out improved

air curtains as a design option for improving the energy efficiency of commercial

refrigeration equipment.

4.3.2 Thermoacoustic Refrigeration

Thermoacoustic refrigeration is a technology that uses high­amplitude sound

waves in a pressurized gas to pump heat from one place to another. It is in the research

stage and, consequently, DOE believes that it would not be practicable to manufacture,

install, and service this technology on the scale necessary to serve the relevant market at

the time of the effective date of the standard. Also, because this technology is in the

research stage, DOE cannot assess whether thermoacoustic refrigeration will have any

adverse impacts on utility to significant subgroups of consumers, result in the

unavailability of any type of commercial refrigeration equipment, or present any

significant adverse impacts on health or safety. DOE, therefore, screened out

thermoacoustic refrigeration as a design option for improving the energy efficiency of

commercial refrigeration equipment.

4.3.3 Magnetic Refrigeration

Magnetic refrigeration is a cooling technology that is based on the magnetocaloric

effect, in which a reversible change in temperature of a suitable material is caused by

exposing the material to a changing magnetic field. Magnetic refrigeration can be used to

attain extremely low temperatures and can be adapted to the cooling temperatures used in

common commercial refrigeration equipment. However, DOE understands that magnetic

refrigeration is in the research stage and, therefore, believes that it would not be

practicable to manufacture, install, and service this technology on the scale and in the

timeframe necessary to serve the relevant market at the time of the effective date of the

standard. Also, because this technology is in the research stage, DOE cannot assess

whether it will have any adverse impacts on utility to significant subgroups of consumers,

result in the unavailability of any type of commercial refrigeration equipment, or present

any significant adverse impacts on health or safety. DOE, therefore, screened out

magnetic refrigeration as a design option for improving the energy efficiency of

commercial refrigeration equipment.

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4.3.4 EHD Enhanced Heat Transfer

EHD enhancement of heat transfer is the result of applying a high­voltage

electrostatic potential field across a heat transfer fluid, such as a refrigerant or refrigerant

mixture. The applied field destabilizes the thermal boundary layer, thereby producing

better mixing of the bulk fluid flow and increasing the net heat transfer coefficient. This

procedure appears to be more effective when applied to phase­change processes (e.g.,

boiling and condensation). Because EHD enhanced heat transfer is in the research stage

and is not being used in commercially produced or sold commercial refrigeration

equipment, DOE believes that it would not be practicable to manufacture, install, and

service this technology on the scale necessary to serve the relevant market at the time of

the effective date of the standard. Also, because this technology is in the research stage,

DOE cannot assess whether it will have any adverse impacts on utility to significant

subgroups of consumers, result in the unavailability of any type of commercial

refrigeration equipment, or present any adverse impacts on health or safety. DOE,

therefore, screened out EHD enhanced heat transfer as a design option for improving the

energy efficiency of commercial refrigeration equipment.

4.3.5 Copper Rotor Motors

Motor manufacturers have long known that substituting copper for die­cast

aluminum in rotors would significantly reduce motor losses and improve electrical

energy efficiency. However, manufacturing die­cast copper rotors require specialized

equipment, significant investment, and proprietary know­how that are not yet suitable for

production of the millions of motors produced annually. DOE recognizes the advantages

of this significant advance in motor technology, but believes that it would not be

practicable to manufacture, install, and service copper rotor motors on the scale necessary

to serve the relevant market at the time of the effective date the standard. Further, DOE

cannot assess whether the manufacture and use of copper rotor motors would have any

adverse impacts on the utility of commercial refrigeration equipment to significant

subgroups of consumers, result in the unavailability of any type of commercial

refrigeration equipment, or present any significant adverse impacts on health or safety.

DOE, therefore, screened out copper rotor motors as a design option for improving the

energy efficiency of commercial refrigeration equipment.

4.4 REMAINING TECHNOLOGIES

After eliminating those technologies that have no effect or do not reduce CDEC

and screening out those technologies that that do not meet the requirements of sections

4(a)(4) and 5(b) of the Process Rule, DOE is considering the technologies in the

following list.

• higher­efficiency lighting

• higher­efficiency lighting ballasts

• remote lighting ballast location

• higher­efficiency evaporator fan motors

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• evaporator fan motor controllers

• higher­efficiency evaporator fan blades

• increased evaporator surface area

• low­pressure differential evaporators

• improved or thicker insulation

• defrost mechanism

• defrost cycle control

• higher­efficiency compressors (self­contained equipment only)

• increased condenser surface area (self­contained equipment only)

• higher­efficiency condenser fan motors (self­contained equipment only)

• higher­efficiency condenser fan blades (self­contained equipment only)

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