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CHAPTER 4. SCREENING ANALYSIS

TABLE OF CONTENTS

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

4.2 TECHNOLOGIES THAT DO NOT AFFECT CALCULATED DAILY ENERGY 

CONSUMPTION................................................................................................................ 4-2

4.2.1 Higher Efficiency Expansion Valves...................................................................... 4-2

4.2.2 Variable-Speed Condenser Fans and Condenser Fan Motor Controllers............... 4-2

4.2.3 Anti-Sweat Heater Controllers................................................................................ 4-3

4.2.4 Liquid-Suction Heat Exchangers............................................................................ 4-3

4.3 SCREENED-OUT TECHNOLOGIES............................................................................... 4-3

4.4 REMAINING TECHNOLOGIES ...................................................................................... 4-4
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CHAPTER 4. SCREENING ANALYSIS

4.1 INTRODUCTION

This chapter describes the screening analysis that the U.S. Department of Energy 

(DOE) performed in support of the energy conservation standards rulemaking for 

commercial refrigeration equipment.

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

of technologies that have the potential 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 evaluated the list of 

remaining technologies using the screening criteria set forth in the Energy Policy and 

Conservation Act (EPCA). (42 U.S.C. 6311–6317)

Section 325(o) of 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 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 in determining whether to eliminate from consideration any 

technology that presents unacceptable problems with respect to the following criteria.

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 DOE determines 

that a technology will have significant adverse impact on the utility of the equipment to 

significant sub-groups 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, DOE will not consider it further.
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Adverse impacts on health or safety. If DOE determines that a technology will 

have significant adverse impacts on health or safety, DOE will not consider it 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 considered in chapter 3 may 

reduce annual energy consumption under field operating conditions, but may not reduce 

calculated daily energy consumption (CDEC), as measured by the American National 

Standards Institute/American Society of Heating, Refrigerating and Air-Conditioning 

Engineers (ANSI/ASHRAE) Standard 72, Method of Testing Commercial Refrigerators 

and Freezers. This is because the ANSI/ASHRAE Standard 72 test procedure calls for 

what is largely a steady-state test. Technologies that reduce energy use only under 

transient conditions, such as fluctuations in ambient temperature and humidity, periods of 

product loading, and frequent door openings, will not affect the measured CDEC.

Therefore, DOE removed from consideration those technologies that do not affect or do 

not reduce CDEC during the tests. These technologies include higher efficiency 

expansion valves, condenser fan motor controllers, anti-sweat heater controllers, and 

liquid-suction heat exchangers (LSHXs).

4.2.1 Higher Efficiency Expansion Valves

Higher efficiency expansion valves can reduce the annual energy consumption of 

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

Because the ANSI/ASHRAE Standard 72 test procedure is largely a steady-state test (i.e.,

there are no changes in refrigerated-product loading or ambient conditions), there is no 

opportunity for higher efficiency expansion valves to reduce CDEC. Consequently, DOE 

did not consider higher efficiency expansion valves in the engineering analysis.

4.2.2 Variable-Speed Condenser Fans and Condenser Fan Motor Controllers

Variable-speed condenser fan motors and controllers attached to the condenser 

fan motor can adapt condenser operation to changing ambient temperatures (effectively 

by creating floating head pressure), and thereby reduce energy consumption of selfcontained commercial refrigeration equipment. However, because testing under the 

ANSI/ASHRAE Standard 72 test procedure is conducted at a constant ambient 

temperature, there is no opportunity to account for the adaptive technology of varying 

condenser fan motor speed to reduce CDEC. Therefore, DOE did not consider variablespeed condenser fan motors or condenser fan motor controllers in the engineering 

analysis.
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4.2.3 Anti-Sweat Heater Controllers

A commercial refrigeration equipment manufacturer typically sizes anti-sweat 

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

operating environment. The end-user must maintain that environment to prevent 

condensation (i.e., fog) from forming on surfaces such as display case glass. Anti-sweat 

heater controllers modulate the operation of anti-sweat heaters by reducing anti-sweat 

heater power when humidity is low. Anti-sweat heater controllers operate most 

effectively when a constant dew point cannot be maintained. Because the 

ANSI/ASHRAE Standard 72 test procedure is conducted at a constant temperature and 

humidity, there is no opportunity to account for the adaptive technology of an anti-sweat 

heater controller to reduce CDEC. Therefore, DOE did not consider anti-sweat heater 

controllers in the engineering analysis.

4.2.4 Liquid-Suction Heat Exchangers

An LSHX is an indirect liquid-to-vapor heat transfer device that evaporates any 

residual liquid refrigerant that remains in the evaporator discharge line, and thereby 

minimizes the risk of liquid refrigerant carrying over to the compressor suction.

Generally, LSHXs are installed in refrigeration systems to ensure proper system 

operation and increase system performance. However, the performance of an LSHX is 

dependent on the specific design used in a given piece of equipment, as well as other 

properties of the system and the operating conditions. A combination of refrigerant type, 

operating temperature, ambient conditions, and other factors determines whether an 

LSHX will increase or decrease the CDEC as measured by the ANSI/ASHRAE Standard 

72 test procedure. In some cases, an LSHX can produce enough of a pressure differential 

across the device, which requires additional compressor energy to overcome, that the 

result is a net increase in energy consumption. Manufacturers have stated that, while an 

LSHX can reduce energy consumption in a lower efficiency or baseline system, these 

devices often produce negative energy impacts in more advanced equipment designs. 

Because an LSHX does not consistently reduce CDEC, DOE did not consider this 

technology in the engineering analysis.

4.3 SCREENED-OUT TECHNOLOGIES

This section addresses a technology, air curtain design, that DOE screened out 

because it did not meet the requirements of sections 4(a) and 5(b) of the Process Rule. In 

making this determination, 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. An air 

curtain is a fan-powered device that creates a moving wall (curtain) of air, which 

separates two spaces of different temperatures. The curtain prevents the loss of 

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

example, and prevents the entry of warm ambient air. Because improved air curtains are 

in the research stage, it would be impracticable to manufacture, install, and service this 

technology on the scale necessary to serve the relevant market at the time the standard

becomes effective. Also, because this technology is in the research stage, DOE cannot 
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assess whether improved air curtains will have any adverse impacts on utility to 

significant sub-groups of consumers, result in the unavailability of any type of 

commercial refrigeration equipment, or present any significant adverse impacts on health 

or safety. Therefore, DOE screened out improved air curtains as a design option for 

improving the energy efficiency of commercial refrigeration equipment.

4.4 REMAINING TECHNOLOGIES

After eliminating those technologies that do not reduce CDEC and screening out 

technologies that do not meet the requirements of sections 4(a)(4) and 5(b) of the Process 

Rule, DOE is considering the following technologies:

• higher efficiency lighting

• higher efficiency lighting ballasts

• remote lighting ballast location

• higher efficiency evaporator fan motors

• variable-speed evaporator fan motors and evaporator fan motor controllers

• increased evaporator surface area

• higher efficiency evaporator fan blades

• low-pressure differential evaporators

• case insulation increases or improvements

• defrost mechanisms

• defrost cycle controls

• vacuum insulated panels

• occupancy sensors for lighting controls

• anti-fog films on transparent doors (equipment with doors only)

• night curtains and radiation shields (equipment without doors only)

• higher efficiency compressors (self-contained equipment only)

• increased condenser surface area (self-contained equipment only)

• higher efficiency condenser fan motors (self-contained equipment only)

• higher efficiency condenser fan blades (self-contained equipment only)