CHAPTER 4. SCREENING ANALYSIS

TABLE OF CONTENTS

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 .............................................................................................. 4-4

LIST OF TABLES

Table 4.2.1 Retained Design Options for Dehumidifiers ........................................................... 4-4

4-iCHAPTER 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 dehumidifiers (c hapter 3 of this preliminary technical support document (TSD)). In t he market and technology assessment, DOE presented an initial list of technologies, or design options that can be used to reduce energy consumption for dehumidifiers. The goal of the screening analysis is to identify any design options that will be elimina ted 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 to the subsequent engineering analysis. Design options which 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 utility 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 dehumidifiers, 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 Op tions

The technologies identified in the market and technology assessment were evaluated pursuant to the criteria set out in the Energy Policy and Conservation Act, as amended (EPCA or the Act). (42 U.S.C. 6291–6309) EPCA provides criteria for prescribi ng 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. 6295(o )( 2 )(A)) It 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 technologically feasible and economically justified, appendix 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 (the

4-1“ 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. 6295 and in part eliminate problematic technologies early in the process of revising an energy efficiency standard. Under the guidelines, DOE el iminates from consideration technologies that present unacceptable problems with respect to the following
four 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

te chnology could not 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 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 significant 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.

Pre

- cooling Air

- to

- Air Heat Exchang ers (for Portable Dehumidifiers up to 45 Pints/Day ) a

DOE is aware that certain whole- home dehumidifiers and portable dehumidifiers with capacities greater than 45 pints per day (pints/day) incorporate pre -cooling air- to

- air heat exchangers , and thus DOE is retaining this technology as a design option for these product
classes.

However, b ased on teardowns and research, DOE determined that portable dehumidifiers with capacities up to 45 pints/day have little room to incorporate additional components w ithin the product case. Adding pre- cooling air

- to

- air heat exchangers to these products would require
increases in case size to accommodate the additional heat exchanger, which would also increase product weight at the expense of consumer utility

.

a As measured by DOE’s proposed amended dehumidifier test procedure which was published in a notice of proposed rulemaking on DATE

. CITE . A capacity of 45 pints/day measured with the amended test procedure is roughly equivalent to a capacity of 75 pints/day measured with the existing dehumidifier test procedure at 10 CFR part 430, subpart B, appendix X.

4-2DOE o bserved that the pre-cooling air- to -air heat exchangers in high- capacity portable
and whole- home dehumidifiers typically occupied a volume of more than three times the combined evaporator and condenser volume. Although no low- capacity portable units on the
market incorporate a pre-cooling air

- to

- air heat exchanger, DOE estimates that to achieve similar
relative gains in efficiency as seen in larger units , portable units would incorporate a similar pre

cooling air- to

- air heat exchanger size in proportion to the evaporator and condenser

. DOE expects that with the addition of an effective pre-cooling air- to

- air heat exchanger, case sizes
would , at a minimum, roughly double for portable dehumidifiers up to 45 pints/day.

DOE believes the increased size and weight for portable dehumidifiers up to 45 pints/day capacity incorporating a pre- cooling air

- to

- air heat exchanger would have an adverse impact on product utility to consumers. Because this design option would result in the unavailability of products with the same size and volume as products currently available on the market, DOE screened out pre

- cooling air

- to

- air heat exchangers as a design option for portable dehumidifiers with capacities up to 45 pints/day

.

Heat Pipes (for Portable Dehumidifiers up to 4 5 Pint/Day)

DOE identified heat pipes as a potential technology to increase dehumidifier efficiency

. Heat pipes perform a similar function as pre -cooling air- to

- air heat exchangers ; lowering the inlet air temperature to increase the efficiency of the refrigeration system, except that heat pipes use a phase -change fluid to transfer heat between the two air streams. Similar to the discussion above for pre-cooling air- to

- air heat exchangers, DOE determined the additional heat exchangers and fluid tubing for heat pipes would require increases in case size, overall weight, and cost for portable dehumidifiers up to 45 pints/day capacity. DOE is not aware of any units available on the market that incorporate the heat pipe design option; however, DOE expects the increase s in case size necessary to accommodate heat pipes to be on the same order of magnitude as for precooling air- to

- air heat exchangers.

DOE believes the increased size and weight for portable dehumidifiers up to 45 pints/day capacity incorpora ting heat pipes would have an adverse impact on product utility to consumers. Because this design option would result in the unavailability of products with the same size and volume as products currently available on the market, DOE screened out heat pipes as a design option for portable dehumidifiers with capacities up to 45 pints/day

.

However, DOE has retained heat pipes as a design option for whole-home and portable dehumidifiers with greater than 45 pints/day capacity. DOE notes that many of these pr oducts already use larger case sizes to accommodate pre -cooling air- to -air heat exchangers. Products incorporating heat pipes would likely require similar case volumes as the products available on the market that include pre- cooling air

- to

- air heat exchangers. Because heat pipes would not likely impact consumer utility for whole -home and portable dehumidifiers with greater than 45 pints/day capacity, D OE has retained this design option for these product classes

.

4-34.2.2 Remaining Design Options

Table 4.2.1 list s the design options for dehumidifiers 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 engineering analysis. DOE has retained each of these design options , with limitations to specific product class as appropriate, because they either are or have previously
been available in commercially available equipment and also meet the criteria listed in section

4.2.1 relating to product utility, availability, and impacts on health and safety.

Table 4.2.1 Retained Design Options for D ehumidifiers

1. Built

- in hygrometer/humidistat 2. Improved compressor efficiency 3. Improved condenser performance

4 . Improved controls

5 . Improved defrost methods

6. Improved demand

- defrost controls 7. Improved evaporator performance 8. Improved fan and fan

- motor efficiency

9. Improved flow

- control devices

10. Low

- standby

- loss electronic controls

11 . Washable air filters

12. Pre

- cooling air

- to

- air heat exchanger (high

capacity portable and whole

- home dehumidifiers)

13. Heat p ipes (high

- capacity portable and whole

home dehumidifiers) 14. Improved refrigeration system insulation

15. Refrigerant

- desiccant systems

4-4