4

- i CHAPTER 4

. SCREENING ANALYSIS

TABLE OF CO NTENTS

4.1 INTRODUCTION

................................ ................................ ................................ ........... 4

- 1

4.2 DISCUSSION OF DESIGN OPTIONS

................................ ................................ .......... 4

- 1

4.2.1 Screened

- Out Design Options

................................ ................................ .......................... 4

- 1

4.2.2 Remaining Design Options

................................ ................................ .............................. 4

- 3

LIST OF TABLES

Table 4.2.1 Retained Design Options for Portable ACs

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- 34-1 CHAPTER 4. SCREENING ANALYSIS

4.1 INTRODUCTION

This chapter discusses the screening analysis conducted by the U.S. Department of Energy (DOE) of the design options identified in the market and technology assessment for portable air conditioners (ACs) ( c hapter 3 of th is preliminary technical support document (TSD)) . In the market and technology assessment, DOE presented an initial list of technologies or design option s that can be used to reduce energy consumption for portable ACs . The goal of the screening analysis is to identify any design options that will be eliminated from further consideration in the rulemaking analyses.

The c andidate design options are assessed based on DOE analysis as well as inputs from interested parties including manufacturers, trade organizations, and energy efficiency advocates. Design options that are judged to be viable approaches for improving energy efficiency are retained as inputs t o the subsequent e ngineering a nalysis. Design options that are not incorporated in commercial products or in working prototypes, or that fail to meet certain criteria as to practi ca bility to manufacture, install and service, as to impacts on product utilit y or availability, or as to health or safety will be eliminated from consideration in accordance with Energy Conservation Program for Consumer Products: Procedures for Consideration of New or Revised Energy Conservation Standards for Consumer Products

. ( 61 FR 36974, section 4(a)(4) and 5(b) ) . The rationale for either screening out or retaining each design option is detailed in the following sections.

4.2 DISCUSSION OF DESIGN OPTIONS

For portable ACs

, the screening criteria specified in section 4.1 were applied to the design options to either retain or eliminate each technology from the engineering analysis.

4.2.1 Screened

- Out Design Options

The technologies identified in the market and technology assessment were evaluated pursuant to the c riteria set out in t he Energy Policy and Conservation Act, as amended (EPCA or the Act). ( 42 U.S.C. 6 291

– 63 09 ) EPCA provides criteria for prescribing new or amended standards, which will achieve the maximum improvement in energy efficiency the Secretary of Energy determines is technologically feasible. (42 U.S.C. 6 295 ( o )( 2 )(A)) It also establishes guidelines for determining whether a standard is economically justified. (42 U.S.C.

6 295 ( o )( 2 )(B)) In view of the EPCA requirements for determining whether a standard is technologically feasible and economically justified, a ppendix A to subpart C of Title 10 Code of Federal Regulations p art 430 (10 CFR p art 430), Procedures, Interpretations and Policies for Consideration of New or Revised Energy Conservation Standards for Consumer Products (the4-2

“ Process Rule ” ), sets forth procedures to guide DOE in the consideration and promulgation of new or revised product efficiency standards under EPCA. These procedures elaborate on the statutory criteria provided in 42 U. S.C. 6 295 and in part eliminate problematic technologies early in the process of revising an energy efficiency standard. Under the guidelines, DOE eliminates from consideration technologies that present unacceptable problems with respect to the following

f our factors:

(1) Technological feasibility. If it is determined that a technology has not been incorporated in commercial products or in working prototypes, then that technology will not be

considered further.

(2) Practicability to manufacture, install, and service. If it is determined that mass production of a technology in commercial products and reliable installation and servicing of the technology could not be achieved on the scale necessary to serve the relevant market at the time

of the ef fective date of the standard, then that technology will not be considered further.

(3) Impacts on product utility to consumers. If a technology is determined to have significant adverse impact on the utility of the product to significant subgroups of consumers, or

result s in the unavailability of any covered product type with performance characteristics (including reliability), f

eatures, size, capacities, and volumes that are substantially the same as products generally available in the United States at the time, it will not be considered further.

(4) Safety of technologies. If it is determined that a technology will have si gnificant adverse impacts on health or safety, it will not be considered further.

The following sections detail the design options that were screened out for this rulemaking

, and the reasons why they were eliminated.

Ducting Insulation

In the market and technology assessment, chapter 3 of this preliminary TSD, DOE identified duct insulation as a potential means for improving portable AC efficiency

. Heat lost from ducts to the conditioned space offsets a significant amount of cooling capacity provided by the portable AC. If manufacturers insulate the product ducting, more heat will be exhausted outside of the conditioned space rather than transferred through the duct.

During manufacturer interviews, DOE requested feedback on the potential use of

insul ated ducts to reduce heat loss to the conditioned space. Manufacturers provided feedback that they have considered insulated ducts to improve performance, but have not identified any insulated ducts that may be collapsed for packaging. DOE notes that no un its in its test and teardown sample included insulated ducts; all units incorporated accordion

- style plastic ducts that ship in a compacted state. When expanded, the ducts typically span more than 6 feet. In the absence of a collapsible insu lated duct, pro duct packaging would have to house the ducting in its expanded configuration.4-3

DOE has screened out insulated ducting based on factors 1, 2, and 3 listed above. For technological feasibility, DOE is not aware of collapsible insulated ducts in any commerc ially available products or working prototypes. Accordingly, i nsulated ducts would not be practicable

to manufacture and ship and would have an adverse impact on consumer utility due to the significantly larger package that would be required to accommodate the insulated ducts.

4.2.2 Remaining Design Options

Table 4.2

. 1 list s the design options for portable ACs that were retained by DOE for at least one of the analyzed product classes . Each of these technologies will be evaluated further in the subsequent en gineering analysis.

Table 4.2

. 1 Retained Design Options for Portable ACs

Increased Heat

- Transfer Surface Area

1. Increased frontal coil area 2. Increased depth of coil (add tube rows) 3. Increased fin density

4. Add subcooler to condenser coil

Increased Heat

- Transfer Coefficients 5. Improved fin design 6. Improved tube design

7 . Spray condensate onto condenser coil

8 . Microchannel heat exchangers Component Improvements

9 . Improved compressor efficiency

10 . Improved blower/fan efficiency

11 . Low

- standby

- power electronic controls

12. Improved d

uct connections

1 3

. Case insulation

Part

- Load Technology Improvements

1 4 . Variable

- speed compressors

1 5 . Thermostatic or electronic expansion valves