CHAPTER 4. SCREENING ANALYSIS

TABLE OF CONTENTS

4.1 INTRODUCTION ........................................................................................................... 4-1 4.2 TECHNOLOGIES THAT DO NO T AFFECT DAILY ENERGY CONSUMPTION............................................................................................................. 4-2 4.2.1 Higher Efficiency Expansion Valves...................................................................4-2 4.2.2 Condenser Fan Motor Controllers .......................................................................4-2 4.2.3 Variable Speed Compressors ............................................................................... 4-3 4.2.4 Liquid-Suction Heat Exchangers .........................................................................4-3 4.3 SCREENED-OUT TECHNOLOGIES............................................................................ 4-3 4.3.1 Thermoacoustic Refrigeration ............................................................................. 4-3 4.3.2 Magnetic Refrigeration ........................................................................................ 4-4 4.3.3 Electro-Hydrodynamic Enhan ced Heat Transfer.................................................4-4 4.3.4 Copper Rotor Motors ...........................................................................................4-4 4.4 REMAINING TECHNOLOGIES ................................................................................... 4-5

4-i4-iiCHAPTER 4. SCREENING ANALYSIS

4.1 INTRODUCTION

This chapter addresses the screening analys is that the U.S. Departm ent of Energy (DOE) conducted in support of the ongoing energy conservation standards rulemakings for refrigerated bottled or canned beverage vending machines. Th ese rulemakings are mandated by the Energy Policy Act of 2005, and are effective for equipment manufactured three years after the date of pub lication of a final rule establishing energy conservation standards.

In the market and technology assessment (c hapter 3), DOE presented an initial list of technologies that can redu ce the energy consumption of re frigerated beverage vending machines. The goal of the screening analysis is to screen out technologies that will not be considered further in the rulemaking analyses . Some of the technologies considered in chapter 3 can reduce annual energy consum ption under real-world conditions, but may not reduce daily energy consumption (DEC), as measured by the American National Standards Institute/American Society of Heating, Refrigerating and Air-Conditioning Engineers (ANSI/ASHRAE) Standard 32.1–2004, Methods of Testing for Rating Vending Machines for Bottled, Canned, and Other Sealed Beverages . DOE removed from consideration those technologies that do not reduce DEC. DOE evaluated the remaining technologies using the screening criteria set forth in the En ergy Policy and Conservation Act (EPCA). (42 U.S.C. 6311–6317)

Section 325(o) EPCA establishes criter ia for prescribing new or amended standards that are designed to achieve the maximum improvement in energy efficiency. Further, EPCA directs the Secretary of En ergy to determine whether a standard is technologically feasible a nd economically justified. (42 U.S.C. 6295(o)(2)(A), as directed by 42 U.S.C. 6316(a)(1)–(3)). EPCA also 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 technologi cally feasible and economically justified, appendix A to subpart C of Title 10, Code of Federal Regulations, Part 430 (10 CFR Part 430), “Procedures, Inte rpretations, and Policies for Consideration of New or Revised Energy Conservation Stan dards 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 problem atic technologies early in the process of prescrib ing or amending an energy effici ency 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 c onsideration any technology that presents unacceptable problems with respec t to the following criteria:

Technological feasibility. Technologies incorporated in commercial equipment or in working prototypes will be considered technologically feasible.

4-1Practicability to manufacture, install, and service. If mass production of a technology in commercial equipment and relia ble installation and servicing of the technology could be achieved on the scale necessa ry to serve the rele vant market at the time of the effective date of the standard, then that technology will be considered practicable to manufacture, install, and service.

Adverse impacts on equipment utility or equipment availability. If DOE determines that a technology has significant adverse impact on the utility of the equipment to significant subgroups of consumer s, or result in the unavailability of any covered equipment type with performance char acteristics (including reliability), features, sizes, capacities, and volumes that are subs tantially the same as equipment generally available in the United States at the tim e, it will not be considered further.

Adverse impacts on health or safety. If DOE determines 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 tec hnology or combination of technologies has unacceptable effects on the policie s stated in section 5(b) of the Process Rule, those technologies will be eliminated from consider ation. If a particular technology fails to meet one or more of the four criteria, it will be screened out. Section 4.3 below documents the reasons for eliminating any technology.

4.2 TECHNOLOGIES THAT DO NOT AFFECT DAILY ENERGY CONSUMPT ION

As stated above, technologies that do not reduce DEC are not considered beneficial in the context of this rulema king. Therefore, DOE removed the following technologies from consideration: higher efficiency expansion valves, condenser fan motor controllers, variable speed compresso rs, and liquid-suction heat exchangers (LSHXs).

4.2.1 Higher Efficiency Expansion Valves

Higher efficiency expansion valves can reduce the annual energy consumption of refrigerated beverage vending machines by adapting to varying loads and am bient conditions. Because ANSI/ASHRAE Standard 32.1–2004 is a steady-state test (i.e., there are no changes in refrigerated-product loading or ambient conditions), there is no opportunity for higher efficiency expa nsion valves to reduce DEC.

4.2.2 Condenser Fan Motor Controllers

Condenser fan motor controllers can adapt condenser operation to changing

am bient temperatures, and thereby reduce annual energy consumption of beverage vending machines. However, because tes ting under the ANSI/ASHRAE Standard 32.1– 2004 test procedure is conducted at a constant temperature, there is no opportunity to account for the effect of a condenser fan motor controller on DEC.

4-24.2.3 Variable Speed Compressors

Variable speed compressors reduce energy consumption under real-world conditions by m atching their capacity to the refrigeration load, which can change due to variations in ambient conditions and pr oduct loading. This technology thereforeeliminates the inefficiencies that occur due to mismatched capacity and load in a singlespeed compressor during part-load operati on. Because the ANSI/ASHRAE Standard 32.1–2004 test procedure prescribes steady-state conditions, a variable speed compressor undergoing this test would be limited to si ngle-speed operation. The resulting energy efficiency ratio would be no better than a properly sized single-speed compressor, so there would be no appreciable energy savings. Similarly, under ANSI/ASHRAE Standard 32.1–2004, the performance of a high- efficiency variable-speed compressor would be comparable to a high-efficiency single-speed compressor.

4.2.4 Liquid-Suction Heat Exchangers

An LSHX is an indirect liquid-to-vapor heat trans fer device that evaporates any residual liquid refrigerant remaining in an evaporator discharge line, and thereby minimizes the risk of liquid refrigerant car rying over to the compressor suction. In general, LSHXs are installed in refrigerati on systems to ensure proper system operation and increasing system performance. Due to the combination of refrigerant type, operating temperature, ambient conditions, and other factors, an LSHX does not consistently reduce DEC, as measured by the ANSI/ASHRAE Standard 32.1–2004 test procedure.

4.3 SCREENED-OUT TECHNOLOGIES

This section addresses the technologies that DOE scr eened out because they did not meet the requirem ents of sections 4(a) a nd 5(b) of the Process Rule. DOE considered the following four factors: (1) technologica l feasibility; (2) practi cability to manufacture, install, and service; (3) adverse impacts on equipment utility to consumers; and (4) adverse impacts on health or safety. Four technologi es were screened out: thermoacoustic refrigeration, magnetic refr igeration, electro-hydrodynamic (EHD) heat exchangers, and copper rotor motors.

4.3.1 Thermoacoustic Refrigeration

Thermoacoustic refrigeration uses high -am plitude sound waves in a pressurized gas to pump heat from one place to another. Because this technology is in the research stage, DOE believes that it would not be prac ticable to manufacture, install, and service this technology on the scale nece ssary to serve the relevant market at the time of the effective date of the standard. Because this technology is in the research stage, DOE also cannot assess whether thermoacoustic refrigeration will have any adverse impacts on utility to significant subgroups of customers, result in the unavailabi lity of any type of refrigerated beverage vending machines, or present any significant adverse impacts on health or safety.

4-34.3.2 Magnetic Refrigeration

Magnetic refrigeration is a cooling technol ogy that is based on the ma gnetocaloric effect, in which a reversible change in te mperature of a suitable material is caused by exposing the material to a cha nging magnetic field. Magnetic re frigeration can be used to attain extremely low temperatures and can be adapted to the cooling temperatures used in common refrigerated beverage vending machines. However, DOE understands that magnetic refrigeration is in the research stage and, therefore, believes that it would not be practicable to manufacture, in stall, and service this tec hnology on the scale and in the timeframe necessary to serve the relevant mark et at the time of the effective date of the standard. Because this technology is in th e research stage, DOE also cannot assess whether it will have any adverse impacts on util ity to significant subgroups of customers, result in the unavailability of any type of refrigerated beverage vending machines, or present any significant adverse im pacts on health or safety.

4.3.3 Electro-Hydrodynamic Enhanced Heat Transfer

EHD enhancement of heat transfer is the result of applying a high-voltage electros tatic potential field acro ss 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 wh en applied to phase-change processes (e.g., boiling and condensation). Because EHD-enhanced heat transfer is in the research stage and is not being used in co mmercially produced or sold refrigerated beverage vending machines, 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. Because this technology is in the research stage, DOE also cannot assess whether it will have a ny adverse impacts on utility to significant subgroups of customers, result in the unavailability of a ny type of beverage vending machines, or present any adverse impacts on health or safety.

4.3.4 Copper Rotor Motors

Motor ma nufacturers have long known that substituting copper for die-cast aluminum in rotors would significantly re duce motor losses and improve electrical energy efficiency. However, manufacturing di e-cast copper rotors requires specialized equipment, significant investment, and proprieta ry know-how 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 believ es that it would not be practicable to manufacture, inst all, and service c opper rotor motors on the scale necessary to serve the relevant market at the time of th e effective date of th e standard. Further, DOE cannot assess whether the manufacture and use of copper rotor motors would have any adverse impacts on the utility of refr igerated beverage vending machines to significant subgroups of customers, result in the unavailability of any type of refrigerated beverage vending machines, or present any significant adverse im pacts on health or safety.

4-44-5 4.4 REMAINING TECHNOLOGIES

After eliminating those technologies that do not reduce DEC and do not m eet the requirements of sections 4(a) and 5(b) of the Process Rule, DOE is considering the following technologies:

 higher efficiency lighting

 higher efficiency lighting ballasts

 higher efficiency evaporator fan motors

 evaporator fan motor controllers

 higher efficiency evaporator fan blades

 improved evaporator design

 low-pressure differential evaporators

 improved or thicker insulation

 defrost mechanism

 higher efficiency compressors

 improved condenser design

 higher efficiency condenser fan motors

 higher efficiency condenser fan blades

 improved glass pack design (for Class A machines)