4

- i 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 TECHNOLOGI ES ...................................................................................... 4-44

- 1 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 t he 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 achi eve 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 ad dition, 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 st andard. 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 fea sibility

. 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.

I mpacts 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.4

- 2 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 t he 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 c hap ter 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

- Conditio ning 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. T echnologies that reduce energy use only under tran sient 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 no t a ffect 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 ther eby 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 variable

speed condenser fan motors or condenser fan motor controllers in the engineering analysis.4

- 3 4.2.3 Anti

- Sweat Heater Controllers

A commercial refrigeration e quipment manufacturer typically sizes anti

- sweat heaters according to the maximum ambient temperature and humidity of a particular operating environment. T he end

- user must maintain that environment to prevent condensation ( i.e., fog) from forming on surfac es 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 m aintained. 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 evaporate s any residual liquid refrigerant that remain s in the evaporator discharge line, an d thereby minimize s the risk of liquid refrigerant carrying over to the compressor suction. G eneral ly , 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
re sult 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. Beca use 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 c onsumers; 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 disp lay area of semivertical commercial refrigerator s, for example, and prevents the entry of warm ambient air. Because improved air curtains are in the research stage, it would be im practicable 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 cannot4

- 4 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 effi ciency of commercial refrigeration equipment.

4.4 REMAINING TECHNOLOGI ES 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 cons idering 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)

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

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