CHAPTER 5. ENGINEERING ANALYSIS

TABLE OF CONTENTS

5.1 INTRODUCTION

........................................................................................................... 5- 1

5.2 TECHNOLOGIES UNABLE TO BE INCLUDED IN THE PRELIMINARY

ANALYSIS

...................................................................................................................... 5-1

5.2.1 Clothes Dryers

.......................................................................................................... ....... 5-2

5.2.1.1 Reverse tumble

............................................................................................... 5-2

5.2.1.2 Improved termination

..................................................................................... 5-2

5.2.2 Room Air Conditioners

................................................................................................... . 5-3

5.2.2.1 Improved Fin Design

..................................................................................... 5-3

5.2.2.2 Improved Tube Design

.................................................................................. 5-3

5.2.2.3 Hydrophilic-Film Coating on Fins

................................................................. 5-3

5.2.2.4 Spray Condensate onto Condenser Coil

........................................................ 5-3

5.2.2.5 Improved Indoor Blower and Outdoor Fan Efficiency

.................................. 5-4

5.2.2.6 Variable Speed Compressors

......................................................................... 5-4

5.2.2.7 Thermostatic or Electronic Expansion Valves

............................................... 5-4

5.2.2.8 Thermostatic Cyclic Controls

........................................................................ 5-4

5.3 PRODUCT CLASSES ANALYZED

.............................................................................. 5-5

5.4 EFFICIENCY LEVELS

................................................................................................... 5-7

5.4.1 Baseline Units

.......................................................................................................... ........ 5-7

5.4.1.1 Active Modes

................................................................................................. 5-8

5.4.1.2 Standby Mode and Off Mode

...................................................................... 5-10

5.4.1.3 Integrated Efficiency

.................................................................................... 5-14

5.4.2 Incremental Efficiency and Standby Levels

.................................................................. 5-15

5.4.2.1 Active Mode

................................................................................................. 5-15

5.4.2.2 Standby Mode and Off Mode

...................................................................... 5-18

5.4.2.3 Integrated Efficiency

.................................................................................... 5-19

5.5 METHODOLOGY OVERVIEW

.................................................................................. 5-21

5.5.1 AHAM Data Request

..................................................................................................... 5 -22

5.5.2 Manufacturer Interviews

................................................................................................ 5-22

5.5.3 Product Teardowns

....................................................................................................... . 5-23

5.5.3.1 Generation of Bill of Materials

.................................................................... 5-23

5.5.3.2 Cost Structure of the Sp readsheet Models

................................................... 5-24

5.5.3.3 Cost Model and Definitions

......................................................................... 5-25

5.5.3.4 Cost Model Assumptions

............................................................................. 5-26

5.5.4 Review of Previous Technical S upport Documents and Models

................................... 5-27

5.5.5 Product Testing

......................................................................................................... ..... 5-27

5.6 ANALYSIS AND RESULTS

........................................................................................ 5-27

5.6.1 Clothes Dryers

.......................................................................................................... ..... 5-27

5.6.1.1 AHAM Data

................................................................................................. 5-27

5.6.1.2 Product Testing

............................................................................................ 5-32

5.6.1.3 Product Teardown

........................................................................................ 5-44

5-i5.6.1.4 Cost-Efficiency Curves

................................................................................ 5-60

5.6.1.5 Manufacturer Interviews

.............................................................................. 5-68

5.6.2 Room Air Conditioners

.................................................................................................. 5-73

5.6.2.1 AHAM Data

................................................................................................. 5-73

5.6.2.2 Manufacturer Interviews

.............................................................................. 5-74

5.6.2.3 Product Teardowns

...................................................................................... 5-76

5.6.2.4 Energy Modeling

......................................................................................... 5-79

5.6.2.5 Energy Testing

............................................................................................. 5-82

5.6.2.6 R-410A Conversion Costs

........................................................................... 5-82

5.6.2.7 Cost-Efficiency Curves

................................................................................ 5-84

LIST OF TABLES

Table 5.3.1 Residential Clothes Dryer Product Classes

.............................................................. 5-5

Table 5.3.2 Room Air Conditioner Product Classes

.................................................................... 5-7 Table 5.4.1 Clothes Dryer Baseline Active Mode Unit Efficiencies

........................................... 5-9

Table 5.4.2 Room Air Conditioner Baseline Ac tive Mode Unit Efficiencies

........................... 5-10 Table 5.4.3 Clothes Dryer Standby and Off Mode Power Input Measurements

....................... 5-13 Table 5.4.4 Room Air Conditioner Standby and Off Mode Power Input Measurements

......... 5-14

Table 5.4.5 Baseline Clothe s Dryer IEF

.................................................................................... 5-15

Table 5.4.6 Baseline Room Air Conditioner I EER for Analyzed Product Classes

................... 5-15 Table 5.4.7 Vented Clothes Dryer Active Mode Efficiency Levels

.......................................... 5-16 Table 5.4.8 Vent-less Clothes Dryer Active Mode Efficiency Levels

...................................... 5-17

Table 5.4.9 Room Air Conditioner Active Mode Efficiency Levels--Product Classes 1

and 3

................................................................................................................... 5-18

Table 5.4.10 Room Air Conditioner Active Mode Ef ficiency Levels--Product Classes 5

and 8

................................................................................................................... 5-18 Table 5.4.11 Clothes Dryer Standby Power Levels

................................................................... 5-19 Table 5.4.12 Room Air Conditioner Standby Power Levels

..................................................... 5-19 Table 5.4.13 Clothes Dryer Integrated Efficiency Levels (IEF)

– Vented Product Classes

...... 5-20 Table 5.4.14 Clothes Dryer Integrated Efficiency Levels (IEF)

– Vent-less Electric Compact (240V)

................................................................................................. 5-20 Table 5.4.15 Clothes Dryer Integrated Efficiency Levels (IEF)

– Vent-less Electric Combination Washer/Dryers

............................................................................. 5-20 Table 5.4.16 Room Air Conditioner Integrated Efficiency Levels (IEER)--Product

Classes 1 and 3

................................................................................................... 5-21 Table 5.4.17 Room Air Conditioner Integrated Efficiency Levels (IEER)--Product

Classes 5 and 8

................................................................................................... 5-21 Table 5.5.1 Engineering Analysis Methods

............................................................................... 5-22 Table 5.5.2 Major Manufacturing Processes

............................................................................. 5-25 Table 5.6.1 AHAM Clothes Dryer Market Share Data Submittal

............................................. 5-28 Table 5.6.2 AHAM Clothes Dryer Shipments a nd Shipment-Weighted Efficiency Data

Submittal

............................................................................................................ 5-28 Table 5.6.3 AHAM Clothes Dryer Incremental Cost Data Submittal

....................................... 5-29

5-iiTable 5.6.4 AHAM Shipment-Weighted Clothes Washer RMC Data Submittal

...................... 5-32 Table 5.6.5 Vented Electric Standard Clothes Dryer Test Unit Features

.................................. 5-33 Table 5.6.6 Vented Electric Compact (240 V), Ga s, and Vent-less Clothes Dryer Test

Unit Features

...................................................................................................... 5-34 Table 5.6.7 Average Change in Clothes Dryer Energy Factor as a Function of Initial RMC as Compared to Initial RMC of 70 Percent

.............................................. 5-43 Table 5.6.8 Results from DOE Testing of Maximum Available Vented Gas Clothes Dryer

.... 5-44 Table 5.6.9 Vented Electric Standard Clothes Drye r Incremental Manufacturing Costs

.......... 5-61 Table 5.6.10 Vented Electric Compact (120V) Clothes Dryer Incremental Manufacturing

Costs

................................................................................................................... 5-62 Table 5.6.11 Vented Electric Compact (240V) Clothes Dryer Incremental Manufacturing

Cost

.................................................................................................................... 5-63 Table 5.6.12 Vented Gas Clothes Dryer Incremental Manufacturing Cost

............................... 5-64 Table 5.6.13 Vent-less Electric Compact (240V) Clothes Dryer Incremental Manufacturing Cost

........................................................................................... 5-65

Table 5.6.14 Vent-less Electric Combination Washer/Dryer Incremental Manufacturing

Cost

.................................................................................................................... 5-66 Table 5.6.15 Standby Power Incremental Manufacturing Cost

................................................. 5-66 Table 5.6.16 Cost-Efficiency Relationship for Vented Electric Standard Clothes Dryers

........ 5-67 Table 5.6.17 Cost-Efficiency Relationship for Vented Electric Compact (120V) Clothes Dryers

................................................................................................................. 5-67 Table 5.6.18 Cost-Efficiency Relationship for Vented Electric Compact (240V) Clothes Dryers

................................................................................................................. 5-67 Table 5.6.19 Cost-Efficiency Relationship for Vented Gas Clothes Dryers

............................. 5-68 Table 5.6.20 Cost-Efficiency Relationship for Vent-less Electric Compact (240V) Clothes Dryers

................................................................................................... 5-68 Table 5.6.21 Cost-Efficiency Relationshi p for Vent-less Electric Combination Washer/Dryers

................................................................................................... 5-68

Table 5.6.22 AHAM Room Air Conditioner Produc t Class Market Share Data Submittal: Product Classes 1 Through 5

............................................................................. 5-73

Table 5.6.23 AHAM Room Air Conditioner Product Class Market Share Data Submittal: Product Classes 6 through 16

............................................................................. 5-73

Table 5.6.24 AHAM Room Air Conditioner Shi pment Weighted Efficiency Data (EER) Submittal: Product Classes 1 through 5

............................................................. 5-74

Table 5.6.25 AHAM Room Air Conditioner Shi pment Weighted Efficiency Data (EER) Submittal: Product Classes 6 through 16

........................................................... 5-74 Table 5.6.26 Manufacturing Cost Increase for Drop-In Conversion to R-410A

....................... 5-84 Table 5.6.27 Retained Design Options fo r Room Air Conditioners

.......................................... 5-84

Table 5.6.28 Size Increases Examined During Room Air Conditioner Design Option Analysis

.............................................................................................................. 5-86 Table 5.6.29 Sizes and Weights of Teardown Units for Product Classes 1, 3, and 5

................ 5-87

Table 5.6.30 Microchannel Condenser Costs

............................................................................ 5-89 Table 5.6.31 Motor Power Rating by Product Capacity

............................................................ 5-90 Table 5.6.32 Comparison of a typical range of sizes for a 70W PSC Double-Shafted

Motor and a 70W BLDC Motor

......................................................................... 5-92

5-iiiTable 5.6.33 Size and Weight of Applicable Rot ary and Scroll Compressors for a 24,000

Btu/h Room Air Conditioner

............................................................................. 5-95 Table 5.6.34 Standby Energy Consumption by Component

...................................................... 5-96 Table 5.6.35 Room Air Conditioner Cost-Standby/Off Mode Power Relationship

................ 5-104 Table 5.6.36 Room Air Conditioner Cost-Efficiency Relationships for Product Classes 1

.... 5-105

Table 5.6.37 Room Air Conditioner Cost-Efficienc y Relationship for Product Class 3

– 8,000 Btu/h Capacity Unit

............................................................................... 5-105

Table 5.6.38 Room Air Conditioner Cost-Effic iency Relationship for Product Class 3

– 12,000 Btu/h Capacity Unit

............................................................................. 5-105 Table 5.6.39 Room Air Conditioner Cost-Efficiency Relationships for Product Class 5

....... 5-106

Table 5.6.40 Room Air Conditioner Cost-Effic iency Relationship for Product Class 8

– 8,000 Btu/h

....................................................................................................... 5-106

Table 5.6.41 Room Air Conditioner Cost-Effic iency Relationship for Product Class 8

– 12,000 Btu/h

..................................................................................................... 5-106

Table 5.6.42 Room Air Conditioner Cost-Effic iency Relationship for Product Class 3

– Average

............................................................................................................ 5-107

Table 5.6.43 Room Air Conditioner Cost-Effic iency Relationship for Product Class 8

– Average

............................................................................................................ 5-107 Table 5.6.44 EER Efficiency Levels fo r Product Classes 2, 4, 6, 7

........................................ 5-108 Table 5.6.45 EER Efficiency Levels for Product Classes 9, 10, 11, 13

.................................. 5-108 Table 5.6.46 EER Efficiency Levels for Product Classes 12, 14, 15, 16

................................ 5-108 Table 5.6.47 IEER Efficiency Levels for Product Classes 2, 4, 6, 7

....................................... 5-109 Table 5.6.48 IEER Efficiency Levels for Product Classes 9, 10, 11, 13

................................. 5-109 Table 5.6.49 IEER Efficiency Levels for Product Classes 12, 14, 15, 16

............................... 5-110 Table 5.6.50 Representative Capacities for Room Air Conditioner Product Classes

.............. 5-110 Table 5.6.51 Extrapolated Incremental Cost Data for Product Classes 2, 4, 6, and 7

............. 5-111 Table 5.6.52 Extrapolated Incremental Cost Data for Product Classes 9, 10, 11, 13

.............. 5-111 Table 5.6.53 Extrapolated Incremental Cost Data for Product Classes 12, 14, 15, 16

............ 5-111

LIST OF FIGURES

Figure 5.5.1 Manufacturing Cost Assessment Stages

................................................................ 5-24 Figure 5.6.1 AHAM Clothes Dryer Cost-Efficiency Curves

..................................................... 5-30 Figure 5.6.2 AHAM Data Submittal for Impact of Initial RMC on Clothes Dryer EF

............. 5-31 Figure 5.6.3 Measured Clothes Dryer Cycle Time versus Rated EF

......................................... 5-37 Figure 5.6.4 Measured Clothes Dryer Energy Consumption versus Rated EF

......................... 5-38 Figure 5.6.5 Measured versus Rated Clothes Dryer EF

............................................................. 5-39 Figure 5.6.6 Disaggregated Clothes Drye r Power Consumption

............................................... 5-40 Figure 5.6.7 Impact of Initial RMC on Clothes Dryer EF (Calculated According to the Existing DOE Test Procedure)

........................................................................... 5-42 Figure 5.6.8 Impact of Initial RMC on Clothes Dryer EF (Calculated Using Adjusted Scaling Factors)

................................................................................................. 5-43

5-ivFigure 5.6.9 Baseline Vented Electric Sta ndard Clothes Dryer Full Production Cost

Distribution

........................................................................................................ 5-47 Figure 5.6.10 Baseline Vented Electric S tandard Clothes Dryer Materials Cost

Distribution

........................................................................................................ 5-48 Figure 5.6.11 Baseline Vented Electric Compact (240V) Clothes Dryer Full Production

Cost Distribution

................................................................................................ 5-49 Figure 5.6.12 Baseline Vented Electric Compact (240V) Clothes Dryer Materials Cost

Distribution

........................................................................................................ 5-50 Figure 5.6.13 Baseline Vented Gas Clothes Dr yer Full Production Cost Distribution

............. 5-51 Figure 5.6.14 Baseline Vented Gas Clothes Dryer Materials Cost Distribution

....................... 5-52 Figure 5.6.15 Baseline Vent-less Electric Compact (240V) Clothes Dryer Full Production

Cost Distribution

................................................................................................ 5-53 Figure 5.6.16 Baseline Vent-less Electric Compact (240V) Clothes Dryer Materials Cost

Distribution

........................................................................................................ 5-54 Figure 5.6.17 Baseline Vent-less Combination Washer/Dryer Full Production Cost

Distribution

........................................................................................................ 5-55 Figure 5.6.18 Baseline Vent-less Combination Washer/Dryer Materials Cost Distribution

..... 5-56 Figure 5.6.19 Vented Electric Standard Clothes Dr yer Cost-Efficiency Curves

....................... 5-61 Figure 5.6.20 Vented Electric Compact (120V) Clothes Dryer Cost-Efficiency Curve

........... 5-62 Figure 5.6.21 Vented Electric Compact (240V) Clothes Dryer Cost-Efficiency Curve

........... 5-63 Figure 5.6.22 Vented Gas Clothes Dryer Cost-Efficiency Curves

............................................ 5-64 Figure 5.6.23 Vent-less Electric Compact (240V) Clot hes Dryer Cost-Efficiency Curve

........ 5-65 Figure 5.6.24 Vent-less Electric Combination Washer /Dryer Cost-Efficiency Curves

............ 5-66 Figure 5.6.25 Efficiency Range of Room Air Conditioner Teardowns

..................................... 5-76 Figure 5.6.26 Baseline HCFC-22 Product Class 3 (12,000 Btu/h) Room Air Conditioner Material Cost Distribution ($157 total)

.............................................................. 5-78 Figure 5.6.27 Baseline HCFC-22 Produc t Class 3 12,000 Btu/h Room Air Conditioner Full Production Cost Distribution ($195 total)

.................................................. 5-79 Figure 5.6.28 Comparison of Energy Modeli ng Results with Rated Air Conditioner

Performance

....................................................................................................... 5-81 Figure 5.6.29 Energy Modeling Results for R-410A Drop-In

................................................... 5-81 Figure 5.6.30 Room Air Conditioner Energy Test Results

........................................................ 5-82 Figure 5.6.31 Size Distributions of Baseline -Efficiency Room Air Conditioners

.................... 5-86 Figure 5.6.32 Cost Differential for Increasing PSC Motor Efficiency from 50% to 70%

........ 5-91 Figure 5.6.33. Cost Differential for Repla cing a Baseline PSC Motor with a BLDC

Motor

.................................................................................................................. 5-92 Figure 5.6.34 Compressor Performance Data

............................................................................ 5-94 Figure 5.6.35 R-410A Compressor Cost

.................................................................................... 5-95 Figure 5.6.36 Product Class 1 Cost-Efficiency Curve

............................................................... 5-98 Figure 5.6.37 Product Class 3 - 8,000 Btu/h Capacity Cost-Efficiency Curve

......................... 5-99 Figure 5.6.38 Product Class 3 - 12,000 Btu/h Capacity Cost-Efficiency Curve

..................... 5-100 Figure 5.6.39 Product Class 5 Cost-Efficiency Curve

............................................................. 5-101 Figure 5.6.40 Product Class 8 - 8,000 Btu/h Capacity Cost-Efficiency Curve

....................... 5-102 Figure 5.6.41 Product Class 8 - 12,000 Btu/h Capacity Cost-Efficiency Curve

..................... 5-103

5-vFigure 5.6.42 Comparison of the Cost-Effective ness of Active and Standby Mode Design Options ............................................................................................................. 5-104

5-viCHAPTER 5. ENGINEERING ANALYSIS

5.1 INTRODUCTION

After conducting the screening analysis, the Department of Energy (DOE) performed an engineering analysis based on the remaining design options. The engineering analysis consists of estimating the energy consumption and c osts of products at various levels of increased efficiency. This section provides an overview of th e engineering analysis (section 5.1), considers technologies which are unable to analyzed for this rulemaking (section 5.2), discusses proposed product classes (section 5.3), establishes baseli ne unit specification (section 5.4.1), discusses incremental efficiency levels (section 5.4.1.2), explains the methodology used during data gathering (5.4.2.3) and discusses the analysis and results (section 5.6) DOE completed a separate engineering analysis for residential clot hes dryers and room air conditioners.

The primary inputs to the engineering analysis are baseline infor mation from the market and technology assessment (Chapter 3 of the preliminary technical support document (preliminary TSD)) and technology options from the screening analysis (Chapter 4). Additional inputs include cost and energy efficiency data, which DOE received from the Association of Home Appliance Manufacturers (AHAM) and quali fied and supplemented through tear-down analysis, energy modeling, and manufacturer interviews. The primary output of the engineering analysis is a set of cost-efficiency curves. In the subsequent markups analysis (Chapter 7), DOE determined customer ( i.e. , product purchaser) prices by applying distribution markups, sales tax and contractor markups. Af ter applying these markups, they serve as the input to the building energy-use and end-use load characterizati on (Chapter 6) and the life-cycle cost (LCC) and payback period (PBP) analyses (Chapter 8).

DOE typically structures its engineering analysis around one of three methodologies. These are: (1) the design-option approach, which calculates the incremental costs of adding specific design options to a baseline model; (2) th e efficiency-level approach, which calculates the relative costs of achieving increases in energy efficiency levels, without regard to the particular design options used to achieve such increas es; and/or (3) the reverse engineering or

cost- assessment approach, which involves a “bottom -u p” manufacturing c ost assessment based

on a detailed bill of materials derived from teardowns of the product being analyzed. Deciding which methodology to use for the engineering analysis depends on the product, the design options under study, and any historical data that DOE can draw on.

5.2 TECHNOLOGIES UNA BLE TO BE INCLUDED IN THE PRELIMINARY

ANALYSIS

In performing the engineering analysis, DOE did not consider for analysis certain technologies that met the screening criteria but were unable to be evaluated for one or more of the following reasons: (1) data are not available to evaluate the energy efficiency characteristics

5-1of the technology; (2) available data suggest that the efficiency benefits of the technology are negligible; and (3) certain technologies cannot be measured according to the conditions and methods specified in the existing test procedure.

In the first case, DOE is unable to adequa tely assess how these technologies impact annual energy consumption. In other cases, av ailable data suggested that some of the design options resulted in such small energy savings as to be negligible. Because DOE intends to focus on the technologies with measurable impact on efficiency, design options with negligible energy savings have been eliminated from further consideration.

5.2.1 Clothes Dryers

5.2.1.1 Reverse tumble

Manufacturers interviewed as part of the preliminary manufacture r interview analysis indicated that such a feature is used primarily for fa bric care. The benefits of reverse tumbling include prevention of balling and wrinkling of the clothes load. No manufacturer indicated they use, or would consider, reverse tumble for increasing efficiency. Tests conducted by one manufacturer, in fact, found that the small size of the test cloths in the DOE test procedure prevents balling and thus no energy efficiency benefit can be measured 1 . At least one

manufacturer stated that reverse tumble could actu ally reduce efficiency by stopping the drum rotation while it is changing directions. For reasons of no demonstrable energy savings and uncertainty as to whether its im pacts can be measured by the existing test procedure, DOE will not further analyze reverse tumble.

5.2.1.2 Improved termination

Improved cycle termination is potentially possible by means of more accurate moisture sensors or by incorporating temperature and moisture sensors together. Alternatively, algorithms may be developed to more accurately detect end-of-cycle conditions. While each of these approaches may produce real-world energy savings by preventing consumers from over-drying the clothes load, the DOE test procedure requires that the test be terminated as soon as a certain level of dryness is achieved. A fixed scaling factor is then applied to the measured energy consumption depending on whether ti med or automatic cycle termination is present. Therefore, improved cycle termination cannot be credited by the test procedure. DOE is currently conducting a clothes dryer te st procedure rulemaking in which this issue, among others, is being considered. If test procedure amendments addressing an improved means of addressing cycle

termination become available in ti me to be considered in this rulemaking, DOE will do so at that time. For this preliminary analysis, howev er, DOE will not further analyze improved

termination.

5-25.2.2 Room Air Conditioners

5.2.2.1 Improved Fin Design

The louvered, raised-lance, or slit-fin fin designs currently used in nearly all room air conditioners are the most effective technologies for heat transfer to air. These designs work by repeatedly interrupting the surface in the f low direction, which prevents thermal boundary layers from growing. The air near the fin remixes with the bulk flow at the end of each louver, and a new boundary layer forms on the next louver. A similar approach is used in high performance heat exchangers in nearly all applications for which high heat transfer is required without incurring high penalties for air-side pressure drop. DOE is not aware of any other improved fin technology that can make further improvements in heat exchanger performance for room air conditioners. Hence, DOE did not fu rther analyze this technology.

5.2.2.2 Improved Tube Design

Rifled tubes are currently used in nearl y all room air conditioners. Variants of conventional spiral rifling have been developed, but they have not been shown to be more effective than the rifling which has become stand ard for tubes used in all air conditioning applications. DOE is not aware of any other improved tube technology that can make further improvements in heat exchanger performance for room air conditioners. Hence, DOE did not further analyze this technology.

DOE did consider use of smaller diameter tube s in the engineering analysis, especially for use with R-410A refrigerant.

5.2.2.3 Hydrophilic-Film Coating on Fins

During interviews conducted during the preliminary analysis phase, manufacturers indicated that hydrophilic film coatings do improve room air conditioner efficiency. However, they indicated that use of these coatings is standa rd practice for room air conditioners. Hence, DOE did not further analyze this technology.

5.2.2.4 Spray Condensate onto Condenser Coil

Spraying of condensate onto the conde nser coil is currently used in all room air conditioners. DOE questione d manufacturers during int erviews about more effective approaches for use of the condensate, but no viable alternatives were identified. DOE measured the condenser fan power impact of the slinger ring on a typical room air conditioner and determined that filling the condensate pan with water and thus initiating slinging action made no noticeable impact on fan power input. The engineering an alysis incorporated use of condensate spraying into the energy use analysis. However, in no case was this technology used as the basis for estimates of possible efficiency improvement, since all baseline products were analyzed assuming they already have this feature. Hence, DOE did not further analyze this technology.

5-35.2.2.5 Improved Indoor Blower and Outdoor Fan Efficiency

The indoor blowers and outdoor fans of current room air conditioners are molded plastic parts with complex geometries. The performance of these blowers and fans has improved as compared to stamped sheet metal fan blades used in the past. DOE expects that there may be potential for incremental improvement in air moving efficiency for some room air conditioners. However, there are no data available which can be used to predict this improvement. During manufacturer interviews, improvement in air moving efficiency through use of better fan blades or blower impellers was not identified as a viable option for improvement in room air conditioner efficiency. Hence, DOE did not further analyze these technologies.

5.2.2.6 Variable Speed Compressors

Variable speed compressors can increase ef ficiency over a broad operating range, but they do not inherently increase the efficiency at the room air conditioner rating point. Because the DOE energy test procedure specifies steady- state maximum-capacity conditions, the speed of a variable-speed compressor w ould remain constant during the test. If the compressor maintains constant speed, there is no opportunity for the compressor to increase the measured energy efficiency ratio (EER) because the power input and work output are constant. In fact, the losses associated with the inverter board would decrease the maximum-capacity EER. Therefore, DOE did not further analyze this technology in the engineering analysis.

5.2.2.7 Thermostatic or Electr onic Expansion Valves

Thermostatic or electronic expansion valves have the capability of maintaining optimum room air conditioner operating parameters ove r a broad range of operating conditions (outdoor and room temperature le vels, during startup transients, and in ca se of high or low refrigerant charge). However, because the DOE energy test procedure for room air conditioners specifies steady state operating conditions, the benefit of the se technologies will not be measured by the test. The design of a capillary expansion device can be adjusted to provide optimum operating conditions for the steady-state test. Therefore, DOE did not consider these technologies further in the engineering analysis.

5.2.2.8 Thermostatic Cyclic Controls

Advanced thermostatic cyclic controls would be designed to control room air conditioner operation if the load is less than the room air conditioner capacity. The DOE energy test procedure, however, measures room air conditioner efficiency at full-capacity steady conditions. Hence, the test procedure cannot measure the ef ficiency benefits of alternative thermostatic controls which might improve control of the cyclin g (or modulation for variable capacity units) of the room air conditioner. Therefore, DOE did not further consider this technology in the engineering analysis.

5-45.3 PRODUCT CLASSES ANALYZED

DOE separated residential clothes dryers and room air conditioners into product classes. Because DOE formulated a separate energy cons ervation standard for each product class, the criteria for separation into different classes are: (1) type of energy used (natural gas or electricity), and (2) capacity or other perfo rmance-related features such as those that provide utility to the consumer, or others deemed a ppropriate by the Secretary that would justify the establishment of a separate energy conservation standard. (42 United States Code (U.S.C.) 6295 (q))

For residential clothes dryers , DOE considered four product classes for vented and two product classes for vent-less dryers, as shown in Table 5.3.1. This is a new analytical structure for clothes dryers, recognizing the unique utility th at vent-less clothes drye rs offer to consumers. (Previously, DOE has described vent-less dryers as condensing dryers. The new designation reflects the actual consumer utility ( i.e., no external vent required) and the potential market availability of vented dryers that also condense). Another new entry with unique utility is the combination washer/dryer ( i.e. , a device which washes and then dries clothes in the samebasket/cavity in a combined cycle). Combination washer/dryers are suitable for spaceconstrained environments ( e.g. , apartments, recreati onal vehicles), and all products of this type appear to utilize vent-less operation. Thus, like other vent-less dryers, such combination washer/dryers can be installed in locations where venting dryers would be precluded due to venting restrictions. Although the DOE clothes drye r test procedure does not currently contain provisions for testing vent-less unit s, DOE has initiated a separa te test procedure rulemaking concurrent with this rulemaking to address active mode test procedur es for clothes dryers and room air conditioners, including potential amendments to allow for the measurement of vent-less clothes dryers. As part of this rulemaking , DOE will consider methodology proposed in an alternate test procedure for condenser clothes dryers in LG Electronics, Inc.’s (LG’s) Petition for Waiver and Denial of the Application for I nterim Waiver, as well as other methodologies suggested by interested parties (see chapter 3). DOE expects that test procedure amendments to incorporate such provisions would be completed in time to be available for this energy conservation standards rulemaking, thus allowing consideration of vent-less product classes.

Table 5.3.1 Residential Clothes Dryer Product Classes

Vented dryers

1. Electric, Standard (4.4 cubic feet (ft 3 ) or greater capacity)

2. Electric, Compact (120 volts (v)) (less than 4.4 ft 3 capacity)

3. Electric, Compact (240 v) (less than 4.4 ft 3 capacity)

4. Gas

Vent-less dryers

5. Electric, Compact (240 v) (less than 4.4 ft 3 capacity)

6. Electric, Combination Washer/Dryer

For room air conditioners , amendments to the Energy Policy and Conservation Act (EPCA) of 1975, Pub. L. 94-163, (42 U.S.C. 6291

– 6309) in the National Appliance Energy

5-5Conservation Act of 1987 (NAECA), Pub. L. 100- 12, initially specified 12 product classes which were applicable to units designed for single- or double-hung window installation or through-thewall installation and based on the following criteria : (1) cooling capacity; (2) the presence of louvered sides (LS); and (3) the capability of reverse cycle ( i.e. , the unit can function as a heat pump). (42 U.S.C. 6295(c)(1)) Capacity is measured in British Thermal Units (Btu) per hour (h). In the final rule published in the Federal Register on September 24, 1997, DOE established an updated set of performance standards (effective October 1, 2000) which included four additional product classes. a Table 5.3.2 lists the existing 16 product classes for room air conditioners. Based on DOE’s estimate that higher -capacity units may be constrained by space limitations in their ability to incorporate design options that could raise energy efficiency, and the assumption that the increments in energy efficiency among the other product classes are well-defined by the

increments in their associated minimum efficiency standards, DOE conducted a full analysis of product classes 1, 3, 5, and 8. The first three of th ese product classes span the range of capacities

of room air conditioners without re verse cycle and with louvered sides. The fourth product class is the intermediate-capacity produc t class for room air-conditioner s without reverse cycle and without louvered sides. DOE then extended this analy sis numerically to the remaining 12 product

classes.

a DOE divided the product class covering units with reverse cy cle and with louvered sides into units of capacity less than 20,000 Btu/h and units 20,000 Btu/h or more. DOE split the product class covering units with reverse cycle and without louvered sides into units of capacity less than 14,000 Btu/h and units 14,000 Btu/h or more. In addition, DOE established two new product classes for units that are desig ned to be installed in casement-slider and casementonly windows. Due to the size cons traints imposed by casement windows, casement units are small in size and typically deliver 5,000 to 10,000 Btu/h in cooling capacity.

5-6Table 5.3.2 Room Air Conditioner Product Classes

Without reverse cycle an d with louvered sides

1. Less than 6,000 Btu/h

2. 6,000 to 7,999 Btu/h

3. 8,000 to 13,999 Btu/h

4. 14,000 to 19,999 Btu/h

5. 20,000 Btu/h or more
Without reverse cycle and without louvered sides

6. Less than 6,000 Btu/h

7. 6,000 to 7,999 Btu/h

8. 8,000 to 13,999 Btu/h

9. 14,000 to 19,999 Btu/h

10. 20,000 Btu/h or more
With reverse cycle

11. With louvered sides and less than 20,000 Btu/h

12. Without louvered sides and less than 14,000 Btu/h

13. With louvered sides and 20,000 Btu/h or more

14. Without louvered sides and 14,000 Btu/h or more

Casement

15. Casement-Only

16. Casement-Slider

5.4 EFFICIENCY LEVELS

5.4.1 Baseline Units

DOE selected baseline unit s as reference points for each product class, against which DOE measured changes resulting from energy cons ervation standards. The baseline unit in each product class represents the basic characteristics of equipment in that class. Typically, a baseline unit is a unit that just meets current required ener gy conservation sta ndards and provides basic consumer utility.

DOE used the baseline units in the engineering analysis and the life-cycle-cost and payback-period analysis. To determine energy savings and changes in price, DOE compared each higher-energy-efficiency or lower-energy-ef ficiency design option with the baseline unit.

As discussed in chapter 3 of this prelimin ary TSD, section 310 of the Energy Independence and Security Act of 2007 (EISA 20 07), Pub. L. 110-140, amended section 325 of EPCA to require that the test procedures for c lothes dryers and room air conditioners be amended to include measurement of standby mode and off mode power, taking into

consideration the most current versions of St andards 62301 and 62087 of the International Electrotechnical Commission (IEC). EPCA, as amended by EISA 2007, also required that any final rule establishing or revising a standard for a covered product, adopted after July 1, 2010,

5-7shall incorporate standby mode and off mode energy use into a single amended or new standard, if feasible. If not feasible, the Secretary shall prescribe within the final rule a separate standard for standby mode and off mode energy consumption. (42 U.S.C. 6295(gg)) DOE initiated a test procedure rulemaking to modify the test procedures for clothes dryers and room air conditioners to provide procedures for measurement of standby and off energy use. DOE published a notice of proposed rulemaking (NOPR) for this rule on Dece mber 9, 2008 (December 2008 NOPR). The December 2008 NOPR proposed new integra ted metrics for residential clothes dryers and room air conditioners, the integrated energy factor (IEF) and the integrated energy efficiency ratio (IEER), which integrate standby and off mode ener gy use with active mode energy use. 72 FR 74639. DOE has not yet published a final rule for the test procedures, but expects that the energy conservation standards for clothes dryers and ro om air conditioners will be based on integrated metrics (IEF and IEER), although the fina l definition of these metrics is still to be determined..For the purpose of the engineering analysis, DOE has analyzed the cost-efficiency relationship for IEF and IEER using the alternat ive definitions for these metrics in the December 2008 NOPR, which integrate only “inactive mode” energy use with active mode energy use. b
Subsequent analyses, such as the LCC and PBP anal yses, and the national impact analysis (NIA) also are based on the integrated metrics.

Test data based on the integrated metrics IE F and IEER, defined in the December 2008 NOPR, are not available for any products. As a re sult, the definition of baseline units using these metrics is based on baseline efficiency char acteristics of products us ing current efficiency metrics and an understanding of the typical energ y use of the products in standby and off modes. The following sections discuss active mode, standby/off mode(s), and integrated metric characteristics for baseline products.

5.4.1.1 Active Modes

The current minimum energy c onservation standards for residential clothes dryers , as measured by EF in pounds (lb) per kilowatt-hour (kWh), became effective on May 14, 1994.

Table 5.4.1 sets forth the standards for the four ve nted clothes dryer product classes. (10 Code of Federal Regulations (CFR) Par t 430.32(h)(2)) DOE used these existing energy conservation

standards to characterize the baseline active mode unit efficiency for each of the vented product

classes. DOE estimated ba seline efficiencies for vent-less dryers based upon testing it conducted on representative units, using the DOE clothe s dryer test procedure without the exhaust simulator, as described in section 5.3 (and, in more detail, chapter 3 of this preliminary TSD).

b DOE proposed in the December 2008 NOPR to define “i nactive mode” as a standby mode other than delay start mode or cycle finished mode (for clothes dryers) or of f-cycle mode (for room air conditioners) that facilitates the activation of active mode by remote switch (including remo te control), internal sensor, or timer, or provides continuous status display.

5-8Table 5.4.1 Clothes Dryer Baseline Active Mode Unit Efficiencies

Product Class EF (lb/kWh)

Vented dryers

1. Electric, Standard (4.4 ft 3 or greater capacity) 3.01

2. Electric, Compact (120 v) (less than 4.4 ft 3 capacity) 3.13

3. Electric, Compact (240 v) (less than 4.4 ft 3 capacity) 2.90

4. Gas 2.67

Vent-less dryers

5. Electric, Compact (240 v) (less than 4.4 ft 3 capacity) 2.37*

6. Electric, Combination Washer/Dryer 1.95*

* Because there are no current energy conservation standards for these product classes, DOE estimated the baseline values on results of tests it conducted on representative units.

The minimum energy conservation standards for room air conditioners , as measured by EER in Btu/h per watt (W), became effect ive on October 1, 2000. Table 5.4.2 sets forth the current minimum energy conser vation standards for the 16 room air conditioner product classes. (10 CFR Part 430.32(b)) DOE used the existing energy conservation standards to characterize the baseline active mode unit efficiency for each product class. As mentioned in section 5.3, DOE analyzed only product classes 1, 3, and 5 (r oom air conditioners with out reverse cycle and with louvered sides, with capacities of less than 6,000 Btu/h; 8,000 to 13,999 Btu/h; and 20,000 Btu/h or more) and subsequently extended the analy sis numerically to the other product classes.

5-9Table 5.4.2 Room Air Conditioner Baseline Active Mode Unit Efficiencies

Product Class EER (Btu/h-W)
Without reverse cycle an d with louvered sides

1. Less than 6,000 Btu/h 9.7

2. 6,000 to 7,999 Btu/h 9.7

3. 8,000 to 13,999 Btu/h 9.8

4. 14,000 to 19,999 Btu/h 9.7

5. 20,000 Btu/h or more 8.5
Without reverse cycle and without louvered sides

6. Less than 6,000 Btu/h 9.0

7. 6,000 to 7,999 Btu/h 9.0

8. 8,000 to 13,999 Btu/h 8.5

9. 14,000 to 19,999 Btu/h 8.5

10. 20,000 Btu/h or more 8.5
With reverse cycle and with louvered sides

11. Less than 20,000 Btu/h 9.0

12. 20,000 Btu/h or more 8.5
With reverse cycle and without louvered sides

13. Less than 14,000 Btu/h 8.5

14. 14,000 Btu/h or more 8.0

Casement

15. Casement-Only 8.7

16. Casement-Slider 9.5

5.4.1.2 Standby Mode and Off Mode

In the December 2008 NOPR, DOE proposed clothes dryer and room air conditioner test procedure amendments to measure standby and of f mode energy use. Among other provisions, “active mode,” “standby mode,” and “off mode” are defined according to t he EISA 2007

amendments to EPCA. 73 FR 74645.

EPCA defines “active mode” as “ the condition in which an energy-using product

– (I) is connected to a main power source; (II) has been activated; and (III) provides 1 or more main functions.” (42 U.S.C. 6295(gg)(1)(A)(i))

EPCA define s “standby mode” as “the condition in which an energy -using product

– (I) is connected to a main power source; and (II) offers 1 or more of the following user-oriented or protective functions: (aa) To facilitate the activation or d eactivation of other functions (including active mode) by remote switch (including remote control), internal sensor, or timer. (bb) Continuous functions, including information or status displays (including clocks) or sensor- based functions.”

5-10(42 U.S.C. 6295(gg)(1)(A)(iii))

EPCA defines “off mode” as “ the condition in which an energy-using product

– (I) is connected to a main power source; and (II) is not providing any standby mode or active mode function.” c (42 U.S.C. 6295(gg)(1)(A)(ii))

In addition, DOE proposed that if power c onsumption drops from a higher-power state to a lower-power state in a given mode, as discussed in Section 5, Paragraph 5.1, note 1 of IEC Standard 62301, to allow sufficient time for the produc t to reach the lower power state before proceeding with the test measurement. 73 FR 74645, 74656, 74658.

DOE determined after the December 2008 NOPR was published that it would continue the clothes dryer and room air conditioner test procedure rulemakin g to allow for consideration of a revised version of IEC Standard 62301, which at that time was expected in July 2009. DOE anticipated, based on review of drafts of the updated IEC Standard 62301, that the revisions

could include different mode definitions. DOE expected to publish a supplemental NOPR (SNOPR) for the test procedure rulemaking in wh ich the new mode definitions are considered. However, more recently, DOE received inf ormation that the revised IEC Standard 62301 would not be available until mid-2010. Therefore, these preliminary analyses for the clothes dryer and room air conditioner energy conservation sta ndards rulemaking are based on the amendments for standby and off mode power measurement that were proposed in the December 2008 NOPR.

DOE measured standby and off mode energy use of residential clothes dryers in its sample of reverse-engineered units. (See s ection 5.6.1.3 for a discussion of the reverse engineering test sample, methodology, and results.) The results of the standby and off mode measurements are shown in Table 5.4.3 below. The compac t (240 V) vent-less and one electric standard vented clothes dryer in the test sample we re unable be measured for standby/off mode power consumption because components energized in standby and off mode were powered off 240 V line power, which could not be accommoda ted by the power meter used by DOE. Additionally, DOE was unable to obtain any test units for electric compact (120 V) vented clothes dryers, so no data is presented for this product class.

c DOE notes that some features that provide consumer u tility, such as displays and remote controls, are associated with standby mode and not off mode . A clothes dryer or room air conditioner is considered to be in “off mode” if it is plugged in to a main power source, is not being used for an active function such as drying clothing or providing cooling, and is consuming power for features other than a display, controls (including a remote control), or sensors required to reactivate it from a low power state. For exampl e, a clothes dryer with electromechanical controls and no display or continuously-energized moisture sensor, but that consumed power for components such as a power supply when the unit was not activated, would be considered to be in off mode when not providing an active function. For room air conditioners, a unit with electromechanical controls and no display or remote control but with a power supply which is consuming energy, for exam ple, could be considered to be in o ff mode while not providing an active

function.

5-11Standby and off modes were determined for c lothes dryers by observing unit function and power consumption for various operating states other than when the dryer was actively drying or tumbling the clothing. The operati ng conditions identified for the clothes dryers which are potential standby and off modes included (1) the unit plugged in, but the power switch turned off; (2) the unit plugged in and powered on, but no drying cycle setting selected; (3) the unit plugged in and powered on, with a “normal” setting sele cted but the drying cycle not started; and (4) the active cycle completed. DOE did not measure power consumption during a delay start

condition because none of the clothes dryers in DOE’s test sample were equipped with such a feature. For some clothes dryers in the test sample with electronic controls, DOE observed that at the completion of the active cycle, power consumption initially was measured at a higher level, then after a period of inactivity of typically several tens of seconds, would drop to a lower level. After another period of inactivity of typically several minutes, these dryers then changed to a state with even lower power consumption, in which all displays were turned off and the on/off “soft” power switch reset to the “off” condition . In this state, power consumption was the same as when the unit was initially plugged in but not powe red on. In other cases, at the completion of the active cycle, the power consumption initially was measured at a higher level, then after a period of inactivity of typically tens of sec onds, would drop to a lower level for which only a single light emitting diode (LED) was illuminated to indicate that the cycle was complete. This mode persisted until the dryer door was opened, at which point the LED turned off and the dryer reverted to an even lower power state in which all displays were turned off and the on/off “soft” power switch reset to the “off” condition . As for the previously discussed case, in this state, the power consumption was the same as for when the unit was initially plugged in but not powered on. Since, for the clothes dryers equipped with electronic controls, the unit would only be powered on in anticipation of starting a drying cycle and would revert to the lowest power consumption state after a period of several minutes after the cycle completed or after the clothes have been removed from the drum, DOE believ es that the lowest power state represents standby/off mode energy use. Further, since DOE observed that all clothes dryers with displays deactivate them in this lowest power state but in clude a soft switch for initiating active mode, such units would be operating in a standby mode ra ther than in off mode. In contrast, clothes dryers with electromechanical controls do not consume any power when the unit is plugged in and not in active mode or once the active cycle has completed, and can thus be considered to operate in off mode. DOE also noted that for operating conditions (2) a nd (3) defined above, after a period of user inactivity (generally between 5 and 10 minutes), the display turns off and the on/off “soft” power switch resets to the “off’ condition, reverting the clothes dryer to the lower power consumption state.

Table 5.4.3 summarizes the power consumption measurements in standby/off mode for each of the clothes dryers in the DOE test sample for which standby power could be measured. Review of this data, along with information on design options obtained during reverseengineering activities, resulted in DOE proposing a level of 2.0 W for baseline power consumption in standby/off mode. This value is based on a maximum measured input power of

1.51 W for a unit with electronic controls, and thus which provides the consumer utility of a display. The model in the DOE test sampl e with this standby power consumption, however, was observed to incorporate a switching power supply, which DOE identified as a design option to reduce standby power consumption. In order to define the baseline level for an assumed clothes

5-12dryer that uses a conventional powe r supply, DOE increased the 1.51 W by the estimated change in standby power associated with changing f rom a conventional to switching power supply. DOE also measured standby power of approximately 0.7 W for other clothes dryers equipped with electronic controls and displays that were observed to dif fer only by having fewer available cycle settings. Because DOE does not intend to re strict consumer utility associated with the number of different cycles, the baseline was chosen to allow the maximum number of settings.

Table 5.4.3 Clothes Dryer Standby and Off Mode Power Input Measurements

Product Class Test Unit EF (lb/kWh) Control Type Power Input (W) Mode

Vented Electric,

Standard 1 3.06 Electromechanical 0.00 Off

2 3.10 Electromechanical 0.00 Off

3 3.15 Electronic 0.69 Standby

4 3.20 Electromechanical 0.00 Off

5 3.40 Electromechanical Standby Vented Electric, Compact (120 V) 6 2.98 Electromechanical 0.00 Off

Vented Gas 7 2.67 Electromechanical 0.00 Off

8 2.76 Electronic 0.69 Standby

9 2.8 Electronic 1.51 Standby

10 3.00 Electronic 0.08 Standby

Vent-less Combination Washer/Dryer 11

- Electronic 0.83 Standby

DOE measured standby/off mode energy use of room air conditioners in order to determine the appropriate energy use ba seline for these modes. The results of these

measurements are shown in Table 5.4.4 below. Note tha t products with electronic controls were capable of operation in inactive mode, as defined in the December 2008 NOPR, while products with electromechanical controls were capable of op eration in off mode. For simplicity, DOE

defined baseline characteristi cs for room air conditioners assuming use of electronic controls. Based on the test data, DOE established a baseli ne standby/off mode power consumption level of

1.4 W. This power input level was higher than all but four of the electronic-control products tested, and the highest power measurement was only 13.5 percent higher than this level.

5-13Table 5.4.4 Room Air Conditioner Standby and Off Mode Power Input Measurements

Product

Class Capacity (Btu/h) EER (Btu/h-W) Control Type Power Input (W)

Inactive

Mode Off Mode

1 5,000 9.7 Electronic 1.59

1 5,200 9.7 Electromechanical 0.20

1 5,200 10.7 Electronic 1.28

1 5,200 11 Electronic 1.46

3 11,800 11.8 Electronic 1.30

3 11,800 10.8 Electronic 0.68

3 12,000 9.8 Electronic 1.36

3 8,400 11.4 Electronic 1.34

3 8,000 9.8 Electronic 0.91

3 8,000 10.8 Electronic 1.40

3 12,000 9.5* Electronic 1.21

5 24,500 8.5 Electronic 0.74

5 24,000 9.4 Electronic 1.404

8 8,000 10.5 Electronic 1.27

8 8,000 9.4 Electronic 1.44

8 8,000 9.6 Electronic 1.52

8 11,600 9.5 Electromechanical 0.03

8 11,500 8.5 Electromechanical 0.03

11 11,600 9.5 Electromechanical 0.03

16 8,000 9.5 Electronic 1.41 *This product was advertised as being through-the-wall ( i.e. product class 8), but it has louvered sides and no way to allow air flow into the condenser fan intake if the louvers were blocked off by a wall sleeve.

5.4.1.3 Integrated Efficiency

DOE based its preliminary analysis for residential clothes dryers on the IEF metric proposed as an alternative option in the Decem ber 2008 NOPR. Baseline IEF levels were

determined from the baseline EF and sta ndby energy use as discussed in sections 5.4.1.1 and

5.4.1.2. The IEF is calculated as the clothes dryer test load weight in lb divided by the sum of

“ active mode ” per- cycle energy use and “inactive mode” per -cycle energy use in kWh. As noted above, inactive mode was defined in the Dece mber 2008 NOPR as a standby mode other than delay start mode or cycle finished mode that facili tates the activation of active mode by remote switch (including remote control), internal sensor, or timer, or that provides continuous status display. This is the standby mode measured under the discussion in section 5.4.1.2 above. The per-cycle energy consumption associated with this standby mode for residential clothes dryers is calculated assuming 416 clothes dr yer cycles in a year and 8,620 hours associated with inactive mode. DOE notes that it is considering amendments to the number of clothes dryer cycles in a year in a separate concurrent test procedure rulemaking to address active mode test procedures for clothes dryers (as distinct from the r ulemaking DOE is also currently conducting to consider revisions to the clothes dryer and room air conditioner test procedures for measuring standby mode and off mode energy use). These amendments would affect the calculated per-cycle energy consumption associated with inactive mode and the calculated IEF. If test procedure amendments addressing the number of clothes dryer cycles per year become available in time to

5-14be considered in this rulemaking, DOE will do so at that time. Table 5.4.5 shows the baseline IEF for each residential clothes dryer product class.

Table 5.4.5 Baseline Clothes Dryer IEF

Product Class EF (lb/kWh) Standby Power (W) IEF (lb/kWh)

Vented dryers

1. Electric, Standard (4.4 ft 3 or greater capacity) 3.01 2.0 2.96

2. Electric, Compact (120 v) (less than 4.4 ft 3 capacity) 3.13 2.0 3.00

3. Electric, Compact (240 v) (less than 4.4 ft 3 capacity) 2.90 2.0 2.79

4. Gas 2.67 2.0 2.63

Vent-less dryers

5. Electric, Compact (240 v) (less than 4.4 ft 3 capacity) 2.37 2.0 2.29

6. Electric, Combination Washer/Dryer 1.95 2.0 1.90

DOE based its preliminary analysis for room air conditioners on the IEER metric proposed as an alternative option in the Decembe r 2008 NOPR. Baseline IEER levels were determined from the baseline EER and standby energy use as discussed in sections 5.4.1.1 and

5.4.1.2. The IEER is calculated as capacity times active mode hours (equal to 750) divided by the sum of active mode annual energy use and inact ive mode, as defined above, annual energy use. This is the standby mode measured under the discussion in section 5.4.1.2 above. The number of hours associated with this standby mode for r oom air conditioners is 5,115 hours per year.

Because IEER depends on capac ity, calculating its baseline value for a product class requires specification of that capacity. For the four product classes and the capacities analyzed in detail for the preliminary analyses, the baseli ne IEERs are as indicated in Table 5.4.6 below.

Table 5.4.6 Baseline Room Air Conditioner IE ER for Analyzed Product Classes

Product Class Capacity (Btu/h) EER (Btu/h-W) Standby Power (W) IEER (Btu/h-W)

1 5,000 9.7 1.4 9.52

3 8,000 9.8 1.4 9.69

3 12,000 9.8 1.4 9.72

5 24,000 8.5 1.4 8.47

8 8,000 8.5 1.4 8.41

8 12,000 8.5 1.4 8.44

5.4.2 Incremental Efficiency and Standby Levels

5.4.2.1 Active Mode

For the majority of the product classes presented in section 5.3, DOE analyzed several efficiency levels and obtained incremental cost data at each of these levels. Table 5.4.7 through Table 5.4.10 provide efficiency levels and the reference source of each level for each of the products under consideration. For most of the product classes, the highest efficiency level was

5-15identified based on a review of available product literature for products commercially available (this applied for gas vented clothes dryers and all room air conditioner product classes). For electric vented and vent-less clothes dryers, the maximum levels ide ntified in Table 5.4.7 and

Table 5.4.8 are based on available re search and product literature on heat pump clothes dryers as

well as discussions with manufacturers.

For residential clothes dryers, DOE considered four efficiency levels beyond the baseline efficiency level for electric standard vented clothes dryers and electric compact (120V and 240V) vented clothes dryers, and three efficiency levels for the gas vented product class, as listed

in Table 5.4.7. These levels were derived primarily from data contained within the California Energy Commission (CEC) and Natural Resources Ca nada (NRCan) product databases. For gas clothes dryers, the highest ef ficiency level (which is the maximum technologically feasible (max-tech) level) is based on the value proposed in the fram ework document and for which AHAM submitted aggregated incremental manuf acturing cost data. As discussed in section 5.6.1.5, multiple manufacturers stated during intervie ws that the current maximum efficiency that is listed for vented gas clothes dryers in the CEC product database is not achievable. Also, as discussed in section 5.6.1.2, DOE testing of the “maximum

- available” gas clothes dryer

determined that this unit did not achieve the ra ted efficiency. For these reasons, DOE is proposing to use the vented gas clothes dryer max-tech value for which AHAM submitted aggregated incremental manufac turing costs. This max-tech level was supported by multiple manufacturers during inte rviews. DOE also added two levels to fill the gap between the baseline and the max-tech for this product class. Since no data was available from either database for electric compact (120 V) clothes dryers, effici ency levels above the baseline for this product class were obtained by scaling the efficiency levels for electric standard unit s by the ratio of the

baseline efficiencies. For elec tric standard and electric compact (240V) clothes dryers, the maxtech level corresponds to the efficiency improvement associated with incorporating heat pump technology, which was based upon manufacturer interview s and available research on heat pump dryers, while the three gap fill levels are derived from certification data. Some of these efficiency levels were changed from those proposed in the framework document, based on comments from interested parties, manufacturer interviews, and more recent certification data.

Table 5.4.7 Vented Clothes Dryer Active Mode Efficiency Levels

Level Efficiency Level Description Efficiency Level (EF) (lb/kWh)

Electric

Standard Electric Compact

(120V) Electric Compact

(240V) Gas

Baseline DOE Standard 3.01 3.13 2.90 2.67

1 Gap Fill 3.10 3.22* 2.98 2.75

2 Gap Fill 3.16 3.29* 3.09 2.85

3 Gap Fill/Maximum Available 3.4 3.54* 3.2 3.02 (maxtech)

4 Max-Tech 4.51 4.70* 4.35

* Estimated by scaling from electric standard clothes dryer efficiency levels.

For vent-less clothes dryers, DOE considered three efficiency levels above the baseline for both electric compact (240 V) and electric combination washer/dryer product classes. For

5-16vent-less electric compact (240 V) clothes dryers, DOE estimated ef ficiency level (EL) 1 using methodology based on a waiver DOE provided to Miele, Inc. (Miele) for its condenser clothes dryer. In that waiver, Miele voluntarily agr eed to maintain the performance of its condenser clothes dryer to within 82.5 percent of the exist ing energy conservation standard for electric standard clothes dryers. 60 FR 9332 (Feb. 17, 1995). That same percentage was applied to the existing energy conservation standard for electric compact (240 V) vented clothes dryers (EF = 2.90) to obtain an EF of 2.39 for electric compact (240 V) vent-less clothes dryers. A gap-fill level for EL 2 was derived based upon NIST test data. For vent-less electric combination washer/dryers, EL 1 was based upon the efficie ncy improvement credit for incorporating automatic termination control per the DOE test procedure. A gap-fill level for EL 2 was derived using the efficiency improvement from design changes to reach EL 3 d for electric standard dryers, scaled based upon the inherently lower ef ficiency of combination washer/dryers. The max-tech for both vent-less electric compact (240 V) and combination washer/dryers was derived from the efficiency improvements associa ted with heat pump technology, as described above for electric standard dryers. DOE recog nizes there is some uncertainty associated with the values based upon data from product data bases, as it is unclear what test procedure was used to

measure EF.

Table 5.4.8 Vent-less Clothes Dryer Active Mode Efficiency Levels

Level Efficiency Level Description Efficiency Level (EF) (lb/kWh)

Electric Compact (240 V) Electric Combination Washer/Dryer

Baseline DOE Test Data 2.37 1.95

1 Gap Fill 2.39* 2.21

2 Gap Fill 2.59† 2.42

3 Max Tech 3.55 3.32 *Determined by scaling the existing Federal standard for vented electric compact (240V) clothes dryers based on Miele’s voluntary plan to maint ain its condenser clothes dryer EF within 82.5 percent of the existing non-condenser clothes dryer standard. 60 FR 9332.
† Based on NIST test data. 2

For room air conditioners , DOE considered varying numbers of efficiency levels, depending on the product class, as indicated in Table 5.4.9 and Ta ble 5.4.10 below. These levels were determined based on the range of efficiency levels associated with products as listed in the CEC, ENERGY STAR, and AHAM produ ct databases and verified to be on sale by a listing on

either a manufacturer’s website or a retailer’s we bsite. DOE added a gap fill efficiency level

between the current DOE standard and the E NERGY STAR efficiency level. The maximum

available level exceeds the CEE Tier 2 level for product class 1, and matches the CEE Tier 2 level for product class 3. For product classes 5 an d 8, the CEE Tier 2 levels are higher than the maximum available product EER, and thus are not included as efficiency levels.

d The design changes associated with EL 2 for electric st andard clothes dryers are not technologically feasible for combination washer/dryers.

5-17Table 5.4.9 Room Air Conditioner Active Mode Ef ficiency Levels--Produc t Classes 1 and 3

Level Efficiency Level Description EER (Btu/h-W)

1: Without Reverse Cycle,

With Louvered Sides, < 6,000 Btu/h 3: Without Reverse Cycle, With Louvered Sides,

8,000 - 13,999 Btu/h

Baseline DOE Standard 9.7 9.8

1 Gap Fill 10.2 10.3

2 Energy Star 10.7 10.8

3 CEE Tier 1 11.2 11.3

4 CEE Tier 2 11.6 11.8

5 Maximum

Available* 12.0

* Based on ENERGY STAR-qualified room air conditioners as of July, 2008 and verification of availability through

retailer website searches.

Table 5.4.10 Room Air Conditioner Active Mode Ef ficiency Levels--Pro duct Classes 5 and

8

Level Efficiency Level Descrip tion EER (Btu/h-W)

5: Without Reverse Cycle, With Louvered Sides,

≥ 20,000 Btu/h 8: Without Reverse Cycle, Without Louvered Sides, 8,000

– 13,999 Btu/h

Baseline DOE Standard 8.5 8.5

1 Gap Fill 9.0 9.0

2 Energy Star 9.4 9.4

3 CEE Tier 1 9.8 9.8

4 Maximum

Available* 10.0 10.8 (8,000 Btu/h) 9.8 (12,000 Btu/h)

* Based on ENERGY STAR-qualified room air conditioners as of July, 2008 and verification of availability through retailer website searches. CEE Tier 2 level is higher th an the maximum available EER for these product classes.

5.4.2.2 Standby Mode and Off Mode

For clothes dryers DOE observed through testing and teardowns that several different features could be associated with successively lo wer standby power levels (SLs). Therefore, DOE was able to define several standby power levels for analysis. Only standby power is addressed because no powe r consumption was observe d in the off mode for test units capable of such a mode. At the baseline standby power level of 2.0 W, the clothes dryer is estimated to be equipped with a full complement of cycle settings, a linear regulated control board power supply, and a display which powers down after a period of use r inactivity. The automatic deactivation of electronic displays was observed in all tested units so equipped and was therefore considered a

baseline feature.

SL 1 is associated with changing from a conventional power supply to a switch-mode power supply. For SL 2, a transformerless power supply enables a microcontroller to remain on

at all times while disabli ng the main power supply whenever the clothes dryer is “asleep”. The control logic monitors the clothes dryer for ke y-presses, door openings, etc., and when user activity is detected, the logic activates the main power supply. These standby power levels, shown in Table 5.4.11, are believed to be the same for all clothes dryer product classes.

5-18Table 5.4.11 Clothes Dryer Standby Power Levels

Level Standby Power Source Power Input (W)

Baseline DOE Test Data and Analysis 2.0

1 DOE Test Data 1.5

2 DOE Test Data (Max-Tech) 0.08

For room air conditioners , DOE selected a single incr emental standby power level for standby mode, based on the data presented in a bove. The standby mode power input at SL 1 is

0.7 W, which was observed in one of the room air conditioners in the test sample and nearly achieved by a second unit.

Baseline room air conditioners with electronic controllers featured a linear regulated power supply and an infrared detector for the remote control. All sampled units with electronic controllers featured a remote control. SL 1 was met by one of the room air conditioners in the test sample and was nearly achieved by a second unit. DOE research suggests that SL1 can be achieved through the substitution of a switch-mode power supply, since both units that met or nearly met SL1 used such power supplies. All other electronic-controlled units used conventional linear regulated power supplies. The selected st andby power levels are summarized in Table

5.4.12 below.

Table 5.4.12 Room Air Conditioner Standby Power Levels

Level Standby Power Source Power Input (W)

Baseline DOE Test Data 1.4

1 DOE Test Data 0.7

5.4.2.3 Integrated Efficiency

For clothes dryers , incremental IEF efficiency levels were determined by assuming that a clothes dryer with baseline energy effici ency (EF) performance would incorporate baseline standby power consumption ( i.e. , 2.0 W). DOE recognizes that many clothes dryers that just meet the current Federal energy conservation standards for EF utilize electromechanical controls, which consume no standby power. There are, ho wever, multiple models rated at baseline energy efficiency performance that incorpora te electronic controls. Thus, DOE assumed that the baseline IEF level for a minimally-compliant unit should include the 2.0 W of standby power. At higher IEF levels, DOE estimated that standby powe r would remain at 2.0 W for those levels that do not strictly require electronic controls to achie ve. For those higher levels that do require electronic controls, DOE added in the design options for standby power improvements in order

of cost effectiveness. This resulted in the incremental IEF efficiency levels shown in Table

5.4.13 through Table 5.4.15.

5-19Table 5.4.13 Clothes Dryer Integrated Efficiency Levels (IEF)

– Vented Product Classes

Level Effici ency Level Description Integrated Efficiency Level (IEF) (lb/kWh)

Electric

Standard Electric Compact

(120V) Electric Compact

(240V) Gas

Baseline DOE Standard + 2.0 W Standby 2.96 3.00 2.79 2.63

1 Gap Fill + 2.0 W Standby 3.04 3.08 2.86 2.71

2 Gap Fill + 2.0 W Standby 3.10 3.15 2.96 2.80

3 Gap Fill/Maximum Available + 2.0 W Standby 3.33 3.37 3.06 2.97

4 Maximum Available + 1.5 W Standby 3.35 3.41 3.10 2.98

5 Maximum Available + 0.08 W Standby 3.40 3.53 3.19 3.02

6 Heat Pump (Max Tech) + 0.08 W Standby 4.52 4.69 4.34

Table 5.4.14 Clothes Dryer Integrated Efficiency Levels (IEF)

– Vent-less Electric Compact (240V)

Level Efficiency Level Description Integrated Efficiency Level (IEF) (lb/kWh) Electric Compact (240 V)

Baseline Baseline + 2.0 W Standby 2.29

1 Baseline + 1.5 W Standby 2.31

2 Baseline + 0.08 W Standby 2.37

3 Gap Fill + 0.08 W Standby 2.39

4 Gap Fill + 0.08 W Standby 2.59

5 Heat Pump (Max-Tech) + 0.08 W Standby 3.54

Table 5.4.15 Clothes Dryer Integrated Efficiency Levels (IEF)

– Vent-less Electric Combination Washer/Dryers

Level Efficiency Level Description Integrated Efficiency Level (IEF) (lb/kWh) Electric Combination Washer/Dryer

Baseline Baseline + 2.0 W Standby 1.90

1 Gap Fill + 2.0 W Standby 2.15

2 Gap Fill + 2.0 W Standby 2.34

3 Gap Fill + 1.5 W Standby 2.36

4 Gap Fill + 0.08 W Standby 2.42

5 Heat Pump (Max-Tech) + 0.08 W Standby 3.31

Incremental IEER efficiency levels for room air conditioners were established at values rounded to the nearest tenth, except for the baseline levels describe d in section 5.4.1.3. The levels were chosen to correspond to the EER efficiency levels discussed in section 5.4.2.1 as closely as was feasible. The selected leve ls are summarized in Table 5.4.16 and Table 5.4.17

below.

5-20Table 5.4.16 Room Air Conditioner Integrated Ef ficiency Levels (IEER)- -Product Classes 1

and 3

Level IEER (Btu/h-W)

1: Without Reverse Cycle,

With Louvered Sides, < 6,000 Btu/h 3: Without Reverse Cycle, With Louvered Sides,

8,000 - 13,999 Btu/h

Baseline 9.52 9.71

1 10.1 10.3

2 10.6 10.8

3 11.1 11.3

4 11.6 11.5

5 12.0

Table 5.4.17 Room Air Conditioner Integrated Ef ficiency Levels (IEER)- -Product Classes 5

and 8

Level IEER (Btu/h-W)

5: Without Reverse Cycle, With Louvered Sides,

≥ 20,000 Btu/h 8: Without Reverse Cycle, Without Louvered Sides, 8,000

– 13,999 Btu/h

Baseline 8.47 8.43

1 9.0 8.9

2 9.4 9.3

3 9.8 9.8

4 10.0

5.5 METHODOLOGY OVERVIEW

DOE typically uses data submitted by AHAM as the primary source of cost information for the engineering analysis. AHAM provided DOE with aggregated incremental manufacturing cost data from its member companies for severa l product classes of vented clothes dryers. However, AHAM did not receive enough re sponses from members to allow aggregation and reporting of data for the remaining clothes drye r product classes and all room air conditioner product classes.

For clothes dryers , DOE conducted an independe nt review of the AHAM data using several methods and data sources. To gain a better understanding of the data submitted by member companies and to be able to relate the costs of improving efficiency to discrete (or system) technologies, DOE reviewed the TSD fr om the previous rulemaking and conducted interviews with clothes drye r manufacturers. DOE also perf ormed detailed product teardowns and cost modeling on several clothes dryer models spanning a range of efficiencies to generate cost-efficiency curves. These cost-efficiency relationships were compared to the AHAM data for validation. Finally, DOE conducted standby pow er testing, as well as detailed energy performance testing at an independent laboratory to gain insights into energy performance in active, standby, and off modes, and disaggregated energy use of components and subsystems.

5-21For room air conditioners , in the absence of industry-supplied data, DOE conducted energy modeling analysis of the products obtained for reverse engineering analysis, product designs for R-410A refrigerant based on the reve rse engineering products, and product designs using R-410A that incorporate energy-saving design options. The manufacturing cost model developed in conjunction with the reverse-engi neering work was used to determine the incremental costs associated with the high-efficiency product designs evaluated in the energy modeling in order to allow development of cost -efficiency relationships for products using R410A refrigerant. DOE supplemented these analyses with a review of the TSD from the previous rulemaking, product testing at an independent la boratory, and manufacturer interviews. Table

5.5.1 below shows which methods DOE used for each product.

Table 5.5.1 Engineering Analysis Methods

Method Product Clothes Dryers Room Air Conditioners

AHAM Data √

Review of Previous TSD √ √

Product Teardown and Manufacturing Cost Modeling √ √

Product Testing √ √

Manufacturer Interviews √ √
Energy Modeling √

5.5.1 AHAM Data Request

In support of this rulemaking effort, DOE requested incremental cost data from AHAM for both of the product categories. (See appe ndix 5A for the data request sheets.) The data represent the average incremental production c ost to improve a baseline unit to a specified efficiency level. This methodology constitutes an eff iciency-level approach to the engineering analysis because DOE examined aggregated inc remental increases in manu facturer selling price at specified levels of energy efficiency. In addition, DOE requested shipments, shipmentweighted average efficiency, and market share efficiency data. As noted in section 5.4.2.3, AHAM did not receive enough responses from member s in order to allow aggregation and reporting of incremental cost data for room air conditioners. Tables of aggregated data for clothes dryers provided to DOE by AHAM are contained in appendix 5B.

5.5.2 Manufacturer Interviews

AHAM provided to DOE shipment-weighted aver age manufacturer costs and capital expenditures. To better unde rstand the manufacturer costs, DO E supplemented these data with information obtained through follow-up manufacture r interviews. These confidential interviews provided a deeper understanding of the various combinations of technologies used to increase product efficiency, and their associated manufacturing costs . Sample questions asked during

interviews are contained in appendix 5C.

5-22During the interviews, DOE also gathered infor mation about the capital expenditures required to increase the efficiency of the ba seline units to various efficiency levels ( i.e.

, conversion capital expenditures by efficiency or energy-use level). The interviews provided

information about the size and the nature of the ca pital investments. DOE also requested information about the depreciation method used to expense the conversion capital.

5.5.3 Product Teardowns

Other than obtaining detailed manuf acturing costs directly from a manufacturer, the most accurate method for determining the producti on cost of a product is to disassemble the unit piece-by-piece and estimate the material and labor cost of each component using a process commonly called a physical teardown. A supplementary method, called a catalog teardown, uses published manufacturer catalogs and supplementary compone nt data to estimate the major physical differences between a product that has been physically disassembled and another similar product. DOE performed physica l teardown analysis on both c lothes dryers and room air conditioners. The teardown methodology is ex plained in section 5.5.3.1 and section 5.5.3.2.

Selection of Units

During the process of selecting units for t eardown, DOE considered 3 main questions:

� What efficiency levels should be ca ptured in the teardown analysis?

� Are there units on the market that capture al l potential efficiency levels and design options?

� Which of the available units are most representative?

In responding to the preceding questions, DOE ge nerally adopts the foll owing criteria for selecting units for teardown analysis:

� The selected products should span the full range of efficiency levels for each product class under consideration;

� Within each product class, if possible, the se lected products should c ome from the same

manufacturer and be within the same product series;

� The selected products should pr imarily come from manufacturer s with large market share in that product class, although the high est efficiency products were chosen irrespective of manufacturer; and

� The selected products should have non-efficiency-related features that are the same as, or similar to, features of other products in the same class and at the same efficiency level.

Additional criteria for selecting the teardown units specific to each product category are

described in section 5.6.1.3 for clothes dryers and secti on 5.6.2.3 for room air conditioners.

5.5.3.1 Generation of Bill of Materials

The end result of each teardown is a struc tured bill of materials (BOM). Structured BOMs describe each equipment part and its relationship to the other parts, in the estimated order

5-23of assembly. The BOMs describe each fabrication and assembl y operation in detail, including the type of equipment needed ( e.g. , stamping presses, injection molding machines, spot-welders, etc.) and the process cycle times. The result is a thorough and explicit model of the production

process.

The BOMs incorporate all materials, components, a nd fasteners, classified as either raw materials or purchased parts and assemblies. The classification into raw materials or purchased parts is based on DOE’s previous industry experience, recent in formation in trade publications, and discussions with high- and low-volum e original equipment manufacturers (OEMs).

For purchased parts, the purchase price is an estimate based on volume-variable price quotations and detailed discussions with suppliers. For parts fabricated in-house, the prices of

“raw” metals ( e.g. , tube, sheet metal) are estimated on the basis of 5-year averages. Other “raw” materials such as plastic resins, insulation materials, etc . are estimated on a current-market basis.

The cost of raw materials wa s determined using prices for copper, steel and aluminum

from the American Metals Market. 3 The prices for rifled and unrifled copper tubing were obtained directly from a tubing manufacturer.

The price of steel drastically increased in 2005, and the price of copper has increased steadily since 2004. Because DOE is using a 5-y ear average in material prices from 2005-2009, these price increases are normali zed, which better represents long-term material prices.

In order to assure that raw material prices DOE used in manufacturing cost estimates are representative of actual costs paid by OEMs, DOE sent a separate material cost questionnaire to the manufacturers that participated in the technical interviews.

5.5.3.2 Cost Structure of the Spreadsheet Models

The manufacturing cost assessment methodology used is a detailed, component-focused technique for rigorously calculating the manufacturing cost of a product (direct materials, direct labor and some overhead costs). Figure 5.5.1 Manufacturing Cost Assessment StagesFigure 5.5.1 shows the three major steps in genera ting the manufacturing cost.

Figure 5.5.1 Manufacturing Cost Assessment Stages

5-24The first step in the manufacturing cost asse ssment was the creation of a complete and structured BOM from the disassembly of the units selected for teardown. The units were dismantled, and each part was characterized according to we ight, manufacturing processes used, dimensions, material, and quantity. The BOM incorporates all materials, components, and

fasteners with estimates of raw material costs and purchased part costs. Assumptions on the sourcing of parts and in-house fabrication were based on industry experience, information in trade publications, and discussions with manufactur ers. Interviews and plant visits were

conducted with manufacturers to ensure ac curacy on methodology and pricing.

Following the development of a detailed BOM, the major manufacturing processes were identified and developed for the spreadsheet model. These proc esses are listed in Table 5.5.2.

Table 5.5.2 Major Manufacturing Processes

Fabrication Finishing Assembly/Joining Quality Control Fixturing Washing Adhesive Bonding Inspecting & Testing Stamping/Pressing Powder Coating Spot Welding Brake Forming De-burring Seam Welding Cutting and Shearing Polishing Packaging Insulating Refrigerant Charging

Turret Punch Tube Forming Enameling

Fabrication process cycle times were e stimated and entered into the BOM. For this analysis, $24.00 per hour was used as the average fully-burdened labor rate based on typical annual wages and benefits of industry employees. In the fina l step of the cost assessment, assembly times and associated direct labor costs were estimated. Once the cost estimate for each teardown unit was finalized, a detailed summary was prepared for relevant components, subassemblies and processes. The BOM thus details all aspects of unit costs.

Design options used in units subject to tea rdown are noted in the summary sheet of each

cost model and are cost-estimated individuall y. Thus, various implementations of design options can be accommodated, ranging from assemblies that are entirely purchased to units that are made entirely from raw materials. Hybrid assemblies, consisting of purchased parts and parts made on

site are thus also accommodated.

5.5.3.3 Cost Model and Definitions

Once DOE disassembled selected units, gathered information from manufacturer catalogs on additional products, and identified technologies, DOE created an appropriate manufacturing cost model that could translate physical in formation into manufacturing production costs. The cost model is based on production activities a nd divides factory costs into the following categories:

5-25Materials: Purchased parts ( i.e. , gas valves, blower motors, etc.), raw materials, ( i.e. , cold rolled steel, copper tube, etc.), a nd indirect materials that are used for processing and

fabrication. Labor: Fabrication, assembly, indirect, and supervisor labor. Fabrication and assembly labor cost are burdened with benefits and supervisory costs. Overhead: Equipment, tooling, and building depreciation, as well as utilities, equipment and tooling maintenance, insurance, and property taxes.

Cost Definitions Because there are many different accounting systems and methods to monitor costs, DOE

defined the above terms as follows:

Direct material: Purchased parts (out-sourced) plus manufactured parts (made in-house from raw materials).

Indirect material: Material used during manufacturing ( e.g. , welding rods, adhesives). Fabrication labor: Labor associated with in-house piece manufacturing. Assembly labor: Labor associated with final assembly. Indirect labor: Labor costs that scaled with fabrication and assembly labor. This included the cost of technicians, manufacturing engineering support, stocking, etc. that were assigned on a span basis. Equipment and plant depreciation: Money allocated to pay for initial equipment installation and replacement as the production equipment is amortized. Tooling depreciation: Cost for initial tooling (including non-recurring engineering and debugging of the tools) and tooling replacement as it wears out or is rendered obsolete. Building depreciation: Money allocated to pay for the building space and the conveyors that feed and/or make up the assembly line. Utilities: Electricity, gas, telephones, etc. Maintenance: Annual money spent on maintaining tooling and equipment. Insurance: Appropriated as a function of unit cost. Property Tax: Appropriated as a function of unit cost.

5.5.3.4 Cost Model Assumptions

As discussed in the previous section, assumptions about manufacturer practices and cost structure played an important role in estimating the final product cost. In converting physical information about the product into cost information, DOE reconstructed manufacturing processes for each component using internal expertise and knowledge of the methods used by the industry. DOE used assumptions regarding the ma nufacturing process parameters ( e.g. , equipment use, labor rates, tooling depreciation, and cost of purchas ed raw materials) to determine the value of each component. DOE then summed the values of the components into assembly costs and, finally, the total product cost. The product cost included the material, labor, and overhead costs associated with the manufacturing facility. The material costs included both direct and indirect

5-26materials. The labor costs included fabrication, as sembly, indirect, dire ct, and supervisor labor rates, including the associated overhead. The labor costs were determined by the type of product (clothes dryer and room air c onditioner) manufactured at the f actory. Overhead costs included equipment depreciation, tooling de preciation, building depreciation, ut ilities, equipment, tooling maintenance, insurance, property, and taxes.

5.5.4 Review of Previous Technical Support Documents and Models

DOE reviewed previous rulemaking TSDs to asse ss their applicability to the current standard setting process for residential clothes dryers and room air conditioner s. These previous rulemaking TSDs served as a source for design options and energy consumption analysis, in addition to other sources. For room air conditioners, the energy model used in the previous rulemaking was updated for use in the current one.

5.5.5 Product Testing

DOE conducted product testing on clothes dryers and room air conditioners according to the relevant DOE test procedures to develop a bett er understanding of the potential efficiency improvements of design options and to develop disa ggregated efficiency data. In addition, DOE performed standby and off mode testing to he lp evaluate possible standby and off modes, energy use in each mode, and strategies manufacturers may take to reduce standby power.

5.6 ANALYSIS AND RESULTS

5.6.1 Clothes Dryers

The clothes dryer engineering analysis wa s performed by considering cost and efficiency information from multiple sources. AHAM provided incr emental manufacturing costs for all but the highest efficiency levels of interest to DOE for vented electric standard and gas clothes dryers. No data were provided for vented electri c compact (120 V) and (240 V) or vent-less electric compact (240 V) and e lectric combination washer/dryer product classes. DOE supplemented these data points by conducting its own engineering analysis, comprised of performance testing at an independent laborator y, standby power testing, and manufacturing cost

estimates from detailed t eardowns of currently-available c lothes dryers. Manufacturer interviews were also conducted to obtain greater insight into the design strategies to improve efficiency and

the associated costs.

5.6.1.1 AHAM Data

AHAM provided to DOE shipment data from it s member companies for clothes dryers. Table 5.6.1 shows market share by EF ranges for electric standard and gas clothes dryer shipments in the years 2005 and 2006. AHAM noted that, in order to maintain confidentiality,

5-27market share for electric standard dryers between EF of 3.20 and 3.29 were incorporated into the EF range between 3.10 and 3.19. Similarly, market share for gas clothes dryers with an EF >

2.94 was incorporated into the EF > 2.85 efficiency bin. AHAM stated it was not able to obtain

sufficient data for vented electric compact (120 V) and (240 V). In addition, market share data for vent-less dryers was unavailable since EF is not currently measured.

Table 5.6.1 AHAM Clothes Dryer Market Share Data Submittal

Vented Electric Standard Vented Gas EF Range

(lb/kWh) Market Share

for 2005 (%) Market Share

for 2006 (%) EF Range (lb/kWh) Market Share

for 2005 (%) Market Share

for 2006 (%)

3.01-3.09 (Baseline = 3.01) 26 33 2.67-2.74 (Baseline = 2.67) 25 28

3.10-3.29 74 67 2.75-2.84 42 44

3.20-3.29 >2.85 32 27

>3.29

On a shipment-weighted basis, the average efficiencies of electric standard and gas clothes dryers sold in the United Sta tes have been stable for the past few years, according to the

AHAM-submitted data shown in Table 5.6.2.

Table 5.6.2 AHAM Clothes Dryer Shipments a nd Shipment-Weighte d Efficiency Data

Submittal

Year Shipments, Domestic + Imports (Thousands of Units) Shipment-Weighted Average Efficiency(EF, cycles/kWh )

Vented Vent-less Vented

Electric

Gas Electric Electric

Gas All

Electric Standard All Compact Compact

240 V Combo Standard Compact

120 V Compact

240 V

1993 3,674 1,156

1994 3,838 1,239

1995 3,823 1,169

1996 3,947 1,193

1997 4,115 1,195

1998 4,482 1,307

1999 4,865 1,444

2000 5,095 1,480

2001 5,117 1,384

2002 5,402 1,490

2003 5,718 5,622 96 1,616

2004 6,262 6,159 103 1,660

2005 6,408 6,330 78 1,707 3.10 2.70

2006 6,360 6,246 114 1,614 3.10 2.70

AHAM provided incremental manufacturing cost da ta for the first three efficiency levels for vented electric standard and gas clothes drye rs, as shown in Table 5.6.3. At the time DOE requested data from AHAM, the efficiency levels of interest were specified as those in the framework document, which were subsequently upda ted during the preliminary analysis based on more recent market information, comments fr om interested parties, and manufacturer

5-28interviews. Therefore, the AHAM cost data are pr esented at the original values of EF to which the aggregated data correspond, while DOE’s cost estimates are presented at the updated levels.

Table 5.6.3 AHAM Clothes Dryer Incremental Cost Data Submittal

Vented Electric Standard Vented Gas Efficiency Level 1 2 3 1 2 3 EF Level, [Original] (lb/kWh) 3.10 3.16 3.39 2.75 2.77 3.02 Average Shipment-Weighted

Incremental Cost ($) for each EF

level Material 9 42 140 20 60 81

Labor 2 11 45 2 6 32

Overhead 2 4 12 2 4 12 Conversion Capital Expenditure Assumptions, (Million $) , Total

for all Manufacturers Building 0.25 9.02 50.18 0.46 29.83 Tooling and Equipment 5.25 37.68 118.93 2.62 37.24 16.15

Avg. One-Time Product Conversion Expenses, (Million $ )

, Total for all Manufacturers R&D 3.62 15.87 58.97 2.99 15.46 12.91

Marketing

Notes

1. While all members use straight -line depreciation, AHAM was no t able to obtain a consistent response on the years used in the calculation.

2. Shaded cells indicate that AHAM did not receive enough input to aggregate increm ental cost data.

Figure 5.6.1 plots the average incremental cost as a function of EF for the AHAM clothes dryer data. The lowest point on the graph indicates the baseline level and therefore has a cost increment of $0. Note that the gas curve exhibits a stee p increase between EL 2 and EL 3. Based on manufacturer interviews, DOE believes that AHAM members suggested fairly significant design changes in order to reach EL 3, even though the original EF values for EL 2 and EL 3 were quite close.

5-29Figure 5.6.1 AHAM Clothes Dr yer Cost-Efficiency Curves

In addition to the cost and efficienc y data, AHAM provided inf ormation to help DOE evaluate a potential change to the clothes dryer test procedure to reflect more current product characteristics. The existing test procedure a ssumes an initial remaining moisture content (RMC) of the test cloth load of 70.0 ± 3.5 percent. It is li kely, however, that this RMC value is no longer representative of typical residential clothes wa shers that use higher spin speeds to remove moisture at the end of the wash cycle. The refore, DOE requested data from AHAM to help

evaluate the effect of a lower initial RMC on measure d EF, as well as to characterize the trends in shipment-weighted clothes washer RMC. Figu re 5.6.2 illustrates the data AHAM provided for the change in EF that is measured when RMC is reduced from nominally 70 percent to nominally 56 percent. It can be seen that, in AHAM’s test sample of 11 baseline clothes dryers, EF decreased by an average of 4 percent when RM C was reduced as described and the existing test procedure was used to calculate EF. Average EF decreased from 3.09 to 2.97 lb/kWh. The test procedure, however, contains a provision in the ca lculation of per-cycle energy consumption that is intended to normalize EF by the reduction in RMC over the course of the drying cycle. There is a scaling factor applied of 66, which is suppose d to represent the nominal change in percent from the starting RMC to the ending one, which is derived from the assumption that the nominal starting RMC is 70 percent and the nominal ending RM C is 4 percent. If the calculation in the test procedure is adjusted to maintain what DOE believes is the intent for normalization of the results, the scaling factor should be changed to 52 to reflect a starting point of 56 percent RMC rather than 70 percent. If that adjustment is made to the AHAM data, EF increases by an average of 22 percent by changing from 70 to 56 percent initial RMC.

5-30Figure 5.6.2 AHAM Data Submittal for Impact of Initial RMC on Clothes Dryer EF

AHAM also provided data for shipments of residential clothes washers for which RMC was reported, along with shipment-weighted RM C. (See Table 5.6.4) These data sets, each of which were disaggregated for front-loading and top-loading clothes washers as well as reported

as overall values for all clothes washers, provide insight into what initial clothes dryer RMC would be most representative of current clothes washer s. RMC has been decreasing consistently, and the data suggest that the initial RMC in the c lothes dryer test procedure of nominally 70 percent is higher than the current shipment-weighted clothes washer average.

5-31Table 5.6.4 AHAM Shipment-Weighted Clothes Washer RMC Data Submittal

Year Clothes Washer Shipments for Which RMC was Reported Shipment-Weighted RMC (%)

FrontLoading TopLoading Total FrontLoading TopLoading Overall

2000 232,714 686,440 919,154 43.6 57.4 53.9

2001 235,989 473,629 709,618 41.3 57.7 52.2

2002 280,667 529,265 809,932 41.5 58.1 52.3

2003 351,411 1,676,877 2,028,288 43.1 54.5 52.5

2004 1,179,813 5,270,285 6,450,098 42.2 52.8 50.9

2005 1,563,108 5,394,511 6,957,619 40.8 52.7 50.1

2006 1,851,218 15,528,279 17,379,497 39.3 51.8 50.5

2007 1,973,825 15,271,142 17,244,967 38.3 51.8 50.2

2008 2,043,024 4,492,059 6,535,083 38.1 51.0 47.0

5.6.1.2 Product Testing

DOE conducted a market survey of clothes dr yer models and their associated features and selected five electric standard, one electric compa ct (240 V), and four gas vented clothes dryers from multiple manufacturers. For vent-less clothes dryers, DOE selected one electric compact (240 V) and one electric combination washer/drye r model. These selections were based on the proposed efficiency levels and the range of product efficiencies available on the market. Because there is no EnergyGuide label required for residenti al clothes dryers, DOE based the selection of units for teardown on the efficiency data avai lable in the CEC product database. DOE was unable to test an electric compact (120 V) clothes dryer since no such model was found to be on

the market in the United States. Table 5.6.5 a nd Table 5.6.6 list features of the tested units.

5-32Table 5.6.5 Vented Electric Standard Clothes Dryer Test Unit Features

Feature Clothes Dryer Test Unit Designation

Vented Electric Standard

#1 #2 #3 #4 #5

Rated EF (cycle/kWh) 3.06 3.10 3.15 3.20 3.4

Rated Drum Capacity (ft 3 ) 7 7 7 5.9 6.1

Controls Electromech

anical Electromech

anical with

Moisture

Sensor PCB Electronic Electromech

anical Electronic

Drum Type Full Cylinder Open Cylinder Open Cylinder Open Cylinder Full Cylinder

Number of

Motors 2 1 1 1 1

Motor Type(s) PSC +

Induction Induction Induction Induction PSC

Air Flow

Direction Back to

Front Back to

Back Back to

Back Back to

Back Back to

Front

Dedicated Hot

Air Duct? No Yes Yes Yes Yes

Inlet Air

Preheat? No No No No No

Heating

Modulation? No No No No No

Automatic Cycle

Termination? Yes Yes Yes Yes Yes

Sensor Type(s) Temp Temp +

Moisture Temp +

Moisture Temp +

Moisture Temp +

Moisture

5-33Table 5.6.6 Vented Electric Compact (240 V), Gas, and Vent-less Clothes Dryer Test Unit

Features

Feature Clothes Dryer Test Unit Designation

Vented

Electric Compact (120 V) Vented Gas Vent-less

Electric Compact (240 V) Vent

- less

Electric

Combo

#6 #7 #8 #9 #10 #11 #12

Rated EF (cycle/kWh) 2.98 2.67 2.76 2.80 3.00

Rated Drum Capacity (ft 3 ) 3.4 5.2 6.7 7 7,3 2.5 2.5

Contro ls Electrome

chanical Electrome

chanical Electronic Electronic Electronic Electronic Electronic

Drum Type Open Cylinder Full Cylinder Open Cylinder Open Cylinder Open Cylinder Full Cylinder Full Cylinder

Number of

Motors 1 1 1 1 1 1 2

Motor Type(s) Induction Induction Induction Induction Induction PSC PSC +

Induction

Air Flow

Direction Back to

Back Back to

Front Back to

Front Back to

Front Back to

Front Back to

Front Front to

Back

Dedicated Hot

Air Duct? Yes No Yes Yes Yes Yes Yes

Inlet Air

Preheat? No No No No No No No

Heating

Modulation? No No No No No No No

Automatic Cycle

Termination? Yes Yes Yes Yes Yes Yes No

Sensor Type(s) Temp +

Moisture Temp Temp +

Moisture Temp +

Moisture Temp +

Moisture Temp

Active Mode Testing Clothes dryer testing was performed on the twelve units in the test sample. The test results included not only the measurements required to evaluate the performance according to the DOE test procedure, but sub-metered component energy consumption data as well, which enabled DOE to quantify patte rns of energy consumption during various stages of the cycle and identify energy efficiency and other drying pe rformance strategies. Each clothes dryer was tested at an independent laboratory according to the DOE test procedure (10 CFR 430 subpart B, appendix D). For the vent-less units, the test was run without the use of the exhaust simulator, as proposed by DOE in LG ’s Petition for Waiver a nd Denial of the Applicati on for Interim Waiver. 71 FR 49437, 49439.

The test procedure consists of running a load of preconditioned test cloth in the clothes dryer at the maximum temperature setting and, if equipped with a timer, at the maximum time setting. For standard-size dryers ( i.e. , with a drum capacity of 4.4 cubic feet (ft 3 ) or greater), the nominal test load weight is 7.00 lb. For compact-size dryers ( i.e. , with a drum capacity less than

4.4 ft 3 ), the nominal test load weight is 3.00 lb. Prior to loading the drum, the cloth is dampened

5-34and spun to obtain an RMC of 66.5

– 73.5 percent. Once the cycle is started, the test load is dried

until the RMC is 2.5

– 5.0 percent, resetting the timer or automatic dry control if necessary.

During this test cycle, the total kWh of electric energy consumed by the clothes dryer is measured, in addition to the “bone dry” e weight of the test load and the starting and ending RMC. For gas clothes dryers, the measurements a lso include the cubic feet of gas used during the cycle and, for gas dryers equipped with a continuously burning pilot light, the cubic feet of gas consumed by the pilot light during 1 hour. In order to calculate EF according to the DOE test procedure, the following calculations are performed.

For electric clothes dryers, the total per-cycle electric dryer energy consumption, E

ce , is

defined as:

E
ce = (66/W

w - W d ) x E t x FU where,

66 	 = an experimentally established value for the percent reduction in the moisture content of the test load during a laboratory test cycle, expressed as a percent

W

w = the moisture content of the wet test load

W d = the moisture content of the dry test load

E t = the total kWh of electrical energy measured during the test

FU = a Field Use factor = 1.18 for time termination control systems = 1.04 for automatic termination control systems

For gas clothes dryers, the total per-cycle gas dryer electrical energy consumption, E ge , is calculated in the same manner as for electric drye rs. Total per-cycle gas dryer energy consumption expressed in kWh, E cg , is defined as:

E g = E ge + [(66/W

w - W d ) x E tg x FU x GEF + E pg x (8760-140/416) x GEF]/3412 where,

E tg = the cubic feet of gas used during the cycle

GEF = the corrected gas heat value (Btu/ft 3 ) = 1.18 for time termination control systems = 1.04 for automatic termination control systems

E pg = the cubic feet of gas used by a continuously burning pilot light in 1 hour 8760 = the number of hours in a year 416 = the representative average number of clothes dryer cycles in a year

140 = the estimated number of hours that the c ontinuously burning pilot light is on during the operation of the clothes dryer for the represen tative average use cycle for clothes dryers (416 cycles per year)

3412 = the conversion factor of Btu/kWh

e “Bone dry” means a condition of a load of test clothes which has been dried in a dryer at maximum temperature for a minimum of 10 minutes, removed and weighed before cool down, and then dried again for 10-minute periods until the final weight change of the load is 1 percent or less.

5-35The value of 66, W

w , W d , FU, and GEF are the same as were defined for electric clothes dryers.

Finally, EF, expressed in lb per kWh, is derived from the per-cycle electrical energy consumption according to:

EF = M/ E

ce for electric clothes dryers

= M/ E g for gas clothes dryers

M = the test load size in lb

Additional instrumentation was provided during th ese tests to measure disaggregated component energy consumption in order to assess which strategies and fe atures could have the greatest impact on efficiency. Watt meters were attached to the following major components which together account for virtually all of the electrica l energy usage of the clothes dryer:

� heating element for electric units;

� gas valve for gas units;

� drum motor;

� blower motor, if separate from the drum motor;

� controller;

� pump for vent-less units, which removes condensate; and

� water valve for vent-less elec tric combination washer/dryer.

Overall trends in key parameters of the c lothes dryers under DOE testing are shown in Figure 5.6.3 and Figure 5.6.4, including average drying times and total per-cycle electrical energy consumption. Each data point represents the average of three tests. DOE also compared

measured EF to rated EF for each of the clot hes dryers in the test sample because manufacturers indicated during interviews that the tolerance s in the existing test procedure can introduce uncertainty in the EF measurement. By ensurin g the testing was conducted under consistent test conditions, DOE intended to normalize the data against allowable variations in ambient conditions and test parameters. Because the vent-less clothes drye rs have not been rated, the EF for these units could only be represented by the value measured during testing.

5-36Figure 5.6.3 Measured Clothes Dryer Cycle Time versus Rated EF

These data show that cycle times for vented electric standard and gas clothes dryers are

shorter between baseline and mid-efficien cy units. However, in both product classes, this trend reverses at the higher efficiency levels. The data also show that, for the compact-sized dryers, a vent-less unit requires about 35 percent more time to dry than the vented version, although this result is likely somewhat skewed by the fact that the vented clothes dryer heating element draws about 10 percent more power than the vent- less dryer’s heater . Finally, these data show a significantly longer drying time associated with the vent-less electric combination washer/dryer. For that particular model tested, the heating element drew less than half the power than that in the other compact clothes dryers (vented and vent-less).

5-37Figure 5.6.4 Measured Clothes Dryer Ener gy Consumption versus Rated EF

The data for total per-cycle energy consum ption demonstrate the expected trend of measured energy use decreasing as a function of rated EF, again with the vent-less data plotted as a function of measured rather than rated EF. The slope for compact units (which include the vent-less combination washer/dryer) is fairl y consistent with the slope for gas clothes dryers, with a somewhat steeper slope observed for vente d electric standard clothes dryers. This potentially demonstrates uncertainty in the EF me asurement, since EF should scale directly with total energy consumption. The test procedure may allow enough variation in the measurement of EF due to the specified tolerance s to introduce uncertainty in the correlation between measured energy consumption and rated EF.

Such uncertainty can be explored by comparing the rated EFs, which are obtained under varying allowable conditions in multiple te st laboratories, to DOE’s measured EFs, whi ch were obtained under consistent conditions in a single labora tory. Figure 5.6.5 presents the comparison for the clothes dryers for which rated EF was available, with a trend-line included to show what the correlation ideally would be. It can be seen that, for many of the units, measured EF does not correlate particularly closely with rated EF. In particular, the measured EFs for gas clothes dryers showed little variation among the four test units . In addition, the max-tech units in both vented electric standard and gas clothes dryers had measured EFs that were lower than the certification

data would indicate.

5-38Figure 5.6.5 Measured versus Rated Clothes Dryer EF

DOE believes that the lack of strong corr elation between measured and rated clothes dryer EF can be traced to the tolerances that are allowed in the test procedure, notably for the ambient test room conditions. Whirlpool Corpora tion (Whirlpool) submitted data to DOE that demonstrates the effect of a change in ambient relative humidity and temperature on EF. Parametric variations in relative humidity from 40 to 60 percent and ambient temperature from 72 to 78 degrees Fahrenheit (°F), which are the limits allowed under the test procedure, produce measured EFs for an electric compact (120 V) clot hes dryer that range from 2.98 to 3.35 lb/kWh. The Whirlpool data submission is reproduced in appe ndix 5B. These data and their implications are currently being considered in a c lothes dryer test procedure rulemaking.

Component-level data recorded from the watt meters during the DOE tests disaggregated the power consumption of individual components, allow ing DOE to evaluate what strategies a manufacturer might choose to pursue higher energy efficiency. Figure 5.6.6 shows the component average power consumption while in use during the cycle for each of the test units. Within a product class, the models are arranged in the figure from lowest to highest EF. For purposes of visualization, heater power consumption and the gas use in equivalent W have been divided by a factor of 10, so that re lative contributions from the other components can be compared. Also, it is recognized that the heater a nd gas burner are cycled on and off towards the end of the drying cycle. While the heating element watts are averages of instantaneous measurements during the periods when the heater is energized, and thus the power measurement

5-39is meaningful, the equivalent gas W are obtained from the total gas energy consumption during the cycle divided by the cycle time. Such an appr oach does not account for the periods during the cycle when the burner is off, but a comparison of instantaneous gas flow rates to the total cubic feet of gas used during the test shows that the assumption of constant burner usage introduces at most a 3 percent error. Therefore, it can be determined from Figure 5.6.6 that the heating element/gas burner is by far the largest contributor to per-cycle energy consumption, and therefore optimization of its usage and design will have a signific ant effect on efficiency. The drum motor (and potentially separate blower motor) have a second-order impact, while the gas valve, pump, and water valve (if any) are negligible in comparison.

Figure 5.6.6 Disaggregated Clothes Dryer Power Consumption

It is difficult to generalize from these data what strategies manufacturers are taking to improve efficiency. Among vented electric sta ndard clothes dryers, it appears that manufacturers are reducing heating element and motor power to achieve higher EFs, although the trend is not strong. That trend is even weaker among the tested gas clothes dryers. However, DOE notes that it did not see significant differences in mea sured EF among these units, so potentially the test sample did not fully capture possible design improvements.

To summarize key findings from the testing of a small number of clothes dryers, DOE

observed that:

5-40� Test procedure tolerances introduc e uncertainty in the EF measurement that is significant in comparison to the EF range between a baseli ne and high efficiency clothes dryer.

� Improvements in the heating element or gas burner may provide a key opportunity for improving EF. A second-order impact c ould be achieved by improvements in the motor(s).

� Modest increases in EF over the baseline can result in reduced drying cycle times.

� Vent-less electric compact (240 V) clothes dr yers do not require drying times that are longer than those acceptable to consumers ( i.e. , typical drying times associated with vented electric standard clothes dryers.

Standby Mode and Off Mode Testing DOE measured standby and off mode power for 10 of the 12 clothes dryers in the test sample, using methodology provided in the International Electrotechnical Commission (IEC) Standard 62301 Ed. 1.0 (2005-06), Household electrical appliances

– Measurement of standby

power . The remaining two clothes drye rs, both vent-less units, incorporated components contributing to standby power that were energized by 240 V line power that could not be measured with the standby power meter used for these tests. Data obtained from this testing are presented in section 5.4.1.2.

RMC Testing

DOE also conducted tests for f our representative clothes dryers (one each of vented electric standard, vented electric compact (120 V) , vented gas, and vent-less electric compact (240 V) product classes) to evaluate the impact of changes in initial RMC on measured EF, supplementing the RMC data AHAM submitted. The unit s were each tested at three different initial RMC levels: (1) nominally 70 percent, re presenting the conditions specified in the current DOE test procedure; (2) nominally 56 perce nt, to compare directly with the AHAM data submittal; and (3) nominally 39 percent, which wa s selected to be close to the weighted-average RMC of front-loading residential clothes washers currently on the market.

Results of these tests, with EF calculated a ccording to the formula provided in the DOE test procedure, are shown in Figure 5.6.7. In general, reducing initial RMC produced a decrease in measured EF for all product classes. Average pe rcentage reductions in EF as a function of

initial RMC are summarized in Table 5.6.7.

5-41Figure 5.6.7 Impact of Initial RMC on Clothes Dryer EF (Calculated According to the Existing DOE Test Procedure)

However, as discussed in section 5.6.1.1, the scaling factor of 66 in the current DOE test procedure is intended to normalize the calculated EF, for which initial and ending RMCs can vary slightly within allowable tolerances, to a re duction in RMC over the course of the test from 70 percent to 4 percent. For tests in whic h the nominal starting RMC is no longer 70, DOE believes that the scaling factor may not be meaningful. Therefore, DOE subsequently calculated the EFs for the test units using scaling factors at each starting RMC that reflected a change from that RMC to 4 percent. For example, for a starting RMC of 56 percent, the scaling factor would be 52 (56 percent initial RMC minus 4 percent ending RMC). The results using adjusted scaling factors are presented in Figure 5.6.8.

5-42Figure 5.6.8 Impact of Initial RMC on Cloth es Dryer EF (Calculated Using Adjusted Scaling Factors)

Using the revised scaling factor methodology , DOE determined that reducing the initial RMC increased EF significantly, as shown in Table 5.6.7.

Table 5.6.7 Average Change in Clothes Dryer Energy Factor as a Function of Initial RMC as Compared to Initial RMC of 70 Percent

Initial RMC % Change in EF using Existing Scaling Factor

% Change in EF using Adjusted Scaling Factor

%

DOE Results AHAM Results DOE Results AHAM Results

56 -3 -4 23 22

39 -10 70

DOE is currently considering amendments to its clothes dryer test procedure to revise the initial RMC to reflect the performance of residential clothes washers currently on the market. However, DOE has not yet published a NOPR for potential test procedure amendments. Therefore, for this Preliminary-NOPR (Pre-NOPR), DOE did not analyze energy conservation standards based on initial RMCs lower than the existing 70 percent. DOE may consider revising the IEF efficiency levels in later stages of this rulemaking as warranted by further research and

comments from i nterested parties.

Maximum-Available Vented Gas Clothes Dryer Testing

5-43After the framework document was published, DOE determined several models of vented gas clothes dryers were listed in the CEC product database with an EF above the maximumavailable efficiency level proposed in the fr amework document. As discussed in section 5.6.1.5, multiple manufacturers stated during interviews that the current maximum efficiency that is listed for vented gas clothes dryers in the CEC pr oduct database is not ac hievable. Therefore,

DOE tested the model that was rated as the maxim um-available efficiency vented gas clothes dryer to help determine an approp riate max-tech level value for the preliminary analyses. DOE purchased three identical units of this model and te sted each three times ac cording to the DOE clothes dryer test procedure. Table 5.6.8 shows the results from this te sting, which indicate that

the maximum-available model was mea sured as having an EF significantly lower than its rated value. Therefore, DOE did not consider this EF va lue for the max-tech level in the preliminary analyses.

Table 5.6.8 Results from DOE Testing of Maximum-Available Vented Gas Clothes Dryers

Unit Measured Average

EF (lb/kWh) % Difference from CEC

Product Database V alue (3.44 EF)

1 2.83 -17.7

2 2.75 -20.1

3 2.82 -18.0

5.6.1.3 Product Teardown

As part of its reverse-engineering process, DOE tore down clothes dryers to identify design features, and corre sponding manufacturing costs, that ar e associated with successively higher efficiency levels. The clothes dryer teardown analysis performed for this engineering analysis included 12 teardown units total for f our of the five product classes, excluding only vented electric compact (120 V) clothes dryers due to lack of availability. For the other vented product classes, DOE selected products such that within that class, the chosen models span the range of EF from baseline to max-tech.

DOE first notes that all of the clothes drye rs it examined are constructed with an outer sheet metal assembly comprising panels that had b een formed by stamping, joined, and painted. This assembly houses the cylindrical drum, drive motors, heater systems, and the associated ducting. Details of these components and sub-assemblies are as follows.

Baseline Construction

For the baseline vented units, the bottom base plate of the cavity holds a single 1/4

– 1/3 horsepower (hp) induction motor which drives both the drum and the blower. For gas clothes dryers, the bottom base plate also holds the gas burner system, which consists of a single stage gas valve, venturi, and gas inlet pipe. A conical duct then directs the hot air generated from the gas burner towards the back of the cabinet, where it flows through a duct to the rear of drum. For

5-44the baseline electric standard clothes dryers, the heating system consists of an electrical

resistance heater which is contained in a duct whi ch covers the back wall of the drum.

For the baseline unit construction, the laundry basket consists of a metal cylinder which has a circular plate attached on the rear to form a drum. The drum is driven by the single induction motor (installed on the bottom base plate) a nd a drive belt. The drum rotates about a shaft mounted on the plate on the rear of the drum. On the front edge of the drum, the drum spins on smooth plastic strips mounted to the front face of the cavity.

The hot air from both gas and electric h eating systems enters from behind the drum, passes through the clothes load, and exits the drum near the front door. The moist air is then pulled through the lint filter and through the blower fan, which is driven by the same single induction motor that rotates the drum. Subsequently, the moist flue air exits through the exhaust pipe leading out the rear of the exterior sheet metal assembly.

The baseline clot hes dryer is also equipped with electromechanical controls which allow the user to select specific cycle settings. DOE also noted in its teardown of baseli ne units and through surveys of products available on the market that baseline clothes dryers feature automatic cycle termination usi ng temperature switches and timer controls. All baseline clothes dryers torn down feature temperature switches in the heater duct and blower/exhaust duct

sections.

The baseline vent-less electric compact (240 V) clothes dryer has a similar construction to the baseline vented electric clothes dryer, with the following differences. A baseline vent-less clothes dryer is equipped with a permanent split capacitor (PSC) motor which drives both the

drum and the blower fan. The drum rotates about a shaft mounted on the plate on the rear of the drum; however, the front edge of the drum spins on two roller wheels mounted to the front face of the cavity. DOE also noted in its teardown that a baseline unit feature s electronic controls as well as automatic cycle termination using temperature sensors.

The baseline vent-less electric compact (240 V) electrical resistance heater is in a

dedicated duct mounted behind the rear of the dr um. The hot air from the heating system enters from behind the drum, passes through the clothes load, and exits the drum near the front door. The moist air is then pulled through the lint filter and through the blower fan, whereupon the air flows through a duct mounted to the base of the cabinet c ontaining an air-to-air cross-flow heat exchanger. Moisture in the warm, moist air condenses as the air flows past the heat exchanger towards the back of the cabinet, where it again enters the dedic ated electric heater duct and repeats the airflow cycle. As part of the heat exchanger system, an additional blower fan is mounted to the single PSC motor, which pulls ambient air from the surroundings and blows it past the air-to-air heat exchanger in a direction perpendicular to the dry cycle air flow. The heat exchanger duct also houses a drain pump, whic h pumps the condensed moisture from the heat exchanger out of the cabinet.

The construction of the baseline combination washer/dryer is more complex than that of a conventional clothes dryer since it is able to run both washing and drying cycles in a single

5-45cabinet using a single drum. The wash basket is contained in a tub, which prevents water from escaping into the cabinet. The tub is mounted on four shock absorbers, which in turn are mounted to the base of the cabinet. Mounted to the bottom of the tub is a large cement block, which dampens vibrations from the wash and spin cycles. An induction motor spins a drive

wheel mounted on the back of the tub via a belt . This induction motor is capable of the high rotational speeds required for spin cycles. The wash basket, comprising a metal cylinder which has a circular plate attached on the rear, rotat es about a shaft mounted to the rear of the drum. The drive system also uses two large ball bearings for the drive wheel and the rear drum shaft.

A PSC motor is also mounted to the bottom of the tub, which drives a blower fan

contained in a dedicated duct mounted to the rear of the tub via a drive belt. The air is blown from this duct to a duct mounted to the top of the tub, which contains the electrical resistance

heater. The hot air flows from the heater duct into the front of the tub, passes through the clothes load, and exits through the rear of the tub into a space between the wash basket and the tub. The air is then pulled back through the dedicated blower fan duct and the airf low cycle repeats.

The combination washer/dryer is also differe nt from a conventional dryer in that it does

not use a lint filter. DOE also noted in its tea rdown that the baseline unit features electronic controls, but that it does not have an automatic termination feature.

Based upon product teardowns, DOE developed the following baseline production cost distributions and materials costs distributions, shown in Figure 5.6.9 through Figure 5.6.18. Depending on the manufacturer and the product ion volume, the depreciation costs may vary from those shown in the figures, which assume a “green

- field” site. For product classes such as vented electric compact (120 V and 240 V), vent -less electric compact (240 V) and vent-less combination washer/dryers, DOE assumed much smaller production volumes than for vented electric standard and vented gas dryers.

5-46Figure 5.6.9 Baseline Vented Electric Standa rd Clothes Dryer Full Production Cost

Distribution

5-47Figure 5.6.10 Baseline Vented Electric Standard Clothes Dryer Mater ials Cost Distribution

5-48Figure 5.6.11 Baseline Vented Electric Compact (240V) Clothes Dryer Full Production

Cost Distribution

5-49Figure 5.6.12 Baseline Vented Electric Compact (240V) Clothes Dryer Materials Cost

Distribution

5-50Figure 5.6.13 Baseline Vented Gas Clothes Dr yer Full Production Cost Distribution

5-51Figure 5.6.14 Baseline Vented Gas Clothes Dryer Materials Cost Distribution

5-52Figure 5.6.15 Baseline Vent-less Electric Compac t (240V) Clothes Dryer Full Production

Cost Distribution

5-53Figure 5.6.16 Baseline Vent-less Electric Comp act (240V) Clothes Dryer Materials Cost

Distribution

5-54Figure 5.6.17 Baseline Vent-less Combinat ion Washer/Dryer Full Production Cost

Distribution

5-55Figure 5.6.18 Baseline Vent-less Co mbination Washer/Dr yer Materials Cost Distribution

Construction at Higher Efficiency Levels
Based on the design options retained from the screening analysis (see chapter 4 of this preliminary TSD), the reverse engineerin g analyses, and discussions with manufacturers, summarized in section 0, DOE developed manufacturing costs associated with various design features necessary to achieve higher efficiencies.

The following are the design changes DO E believes would be necessary to meet each efficiency level, which were subsequently modeled to obtain incremental manufacturing cost

estimates.

Vented Electric Clothes Dryers Efficiency Level 1

Based on characteristics of units selected for teardown and based on discussions with manufacturers, DOE research suggests that EL 1 is achieved in vented electric clothes dryers through three changes:

1. Switching to Open Cylinder Drum

5-56This design change can allow better air flow through the drum. The drum suspension system is also changed to a roller wheel design with wheels at the front and back edges of the drum as the bearing system in order minimize frictional losses and decrease the load on the

motor.

2. Dedicated Heater Duct

The hot air flow duct that directs the air into the drum through the back would be changed from the baseline duct to a dedicated duct which directs air flow more directly into the

drum and reduces heat losses.

3. Change in Air Flow Patterns
The air flow through the drum would change from a baseline back to front air flow, to flowing in through one side of the back and exiting on the other. This design change requires an outlet duct from the drum that attaches to the rear of the drum, which then leads to the blower

duct and the exhaust duct. DOE notes that the costs associated with these design options will differ for standard and compact-sized drye rs because of the different amounts of materials required for structural design changes.

Efficiency Level 2

Based on research and discussion with manufac turers, DOE research suggests that for EL 2, manufacturers would apply the same design changes as used for EL 1 and additionally incorporate inlet air preheating, which require s better airflow and moisture control.

1. Inlet air pre-heating
Inlet air pre-heating requires an air-to-air heat exchanger (with added ducting) in order to recover exhaust heat energy with which to preheat inlet air. To prevent condensation, moisture sensors and multi-speed blowers are required to adjust airflow rates and to allow for more accurate control of the drying cycle.

2. Moisture Sensing and Variable Airflow
Moisture sensing requires a separate measur ement and control board, which can be used in conjunction with electromechanical controls. Since baseline motors d rive both the drum and the fan, variable airflow requires the adoption of dedicated drum and fan blower motors. Both motors would likely be PSC-style motors, with the drum motor featuring single-speed and the blower motor triple-speed operation. The speed of the blower motor would be controlled by the

control board that also reads the moisture.

Efficiency Level 3 DOE research suggests that manufacturers would likely add modulating heat to the platform described for EL 2 to achieve EL 3. A modulating-heat design is less likely to benefit from inlet air preheating (since the exit air temperature can be closely controlled) so the inlet air pre-heater described for EL2 would likely be dropped. Therefore, it was not included in the design changes for this efficiency level.

5-571. Modulating Heat
For the design change, the control system would have to be upgraded to allow modulation. To accurately control the tempera ture, manufacturers are likely to switch to electronic controls that incorporate bidirectional triode thyristors (Triacs) or similar solid-state approaches to control the heat output. A variable-s peed fan motor is likely required also to seamlessly match the heat output of the hea ter coil. Typically, manufacturers incorporate electronically-commutated or equivalent motor de signs for such applications.

Efficiency Level 4 DOE research suggests that EL 4 would require the use of heat pump technology. As a starting point, this level would incorporate most fea tures described for EL 2. Two features would likely be omitted, however: the airflow rerouting de scribed in EL 1 as well as the pre-heater described in EL 2. Other required design fe atures would be a more sophisticated control system, an upgraded air flow system, a booster he ater, and a condensate removal system.

1. Heat Pump System
The heat pump system would be made up of a reciprocating compressor, evaporator, condenser, and sealed system components. Existing heat pump clothes dryer design schematics suggest the use of tube and fin heater exchange rs with wide evaporator fin spacing to prevent lint foiling. In order to handle the variation in heating load throughout the drying cycle, a thermostatic expansion valve is used to control the refrigerant flow. Standard and compact-size dryers would require different material costs for this design option because of the different sizes of the heat exchangers and shipping packaging.

2. Electronic Controller, Thermal and Moisture Sensing
A heat pump dryer would likely requi re sophisticated moisture, airflow, and temperature control to maximize the energy savings. Thus, an electronic controller, moisture sensors, and multiple thermal sensors are incorporated into this efficiency level.

3. Upgraded Airflow System
A heat pump dryer is expected to require dedicated fan and drum motors, as described in EL 2. However, the additional pressure drop imposed by ducting, heat exchangers, etc. will likely double the shaft power requirements of the fan mot or. The size and wire density of the lint

filter would also need to be increase d to prevent lint migration past the filter to the heat exchanger.

4. Booster Heater
Because of the long warm-up times associated with a heat pump system, and the consumer demand for shorter dry cycles, DOE believes that manufacturers could incorporate a booster heating element. This heating element would be undersized compared to the conventional heating element and would run only during the warm-up phase.

5. Condensate Removal

5-58Since a heat pump dryer produces condensate , a condensate removal system is expected to be standard feature in a heat pump dryer, just as it is in condensing dryers.

Gas Clothes Dryers

DOE believes that the same fundamental design changes described above for vented electric standard dryers for EL 1 through EL 3 would be applied to ve nted gas clothes dryers. Because of inherent differences in the designs between gas and electric clothes dryers ( e.g. , different ducting, heat sources, etc.), the costs at each efficiency level are not identical. Most notably for EL 3, the modulation of gas heat requires significantly different component changes as compared to modulating electric heat.

For EL 3, DOE believes that manufactur ers would switch from the baseline single-stage gas valve to a modulating gas valve. DOE is not aware of any gas-fired clothes dryers with modulating gas valves on the market today, but notes the availability of modulating gas valves for other residential appliance applications. Additional controls would be required to control the gas valve modulation. As with the EL 3 design changes for electric standard dryers, the same disaggregated motor design (with additional controls) would also be incorporated into this level.

Vent-less Electric Compact (240 V) Clothes Dryers DOE believes that essentially the same chan ges described above for vented electric clothes dryers for EL 1, EL 3, and EL 4 would be applied to vent-less electric compact (240 V) clothes dryers. However, because the baseline unit already c ontains a dedicated heat duct, only the remaining design options for vented electric clothes dryer EL 1 would need to be applied to EL 1 for this product class. Also, because the EL 2 design changes applied to vented electric clothes dryers were based upon inlet air preheati ng, these design changes would not be applied to a vent-less electric compact (240 V) clothes dryer because it al ready recirculates the air back through the system. For this reason, the EL 3 and EL 4 design changes for vented electric clothes dryers are applied as EL 2 and EL 3, respectively, for this product class. DOE also notes that the

baseline vent-less electric compact (240 V) clothes dryer already contains electronic controls; therefore, certain desi gn options such as moisture sensing and variable speed motor control will require a smaller incre mental manufacturing cost.

Vent-less Electric Combination Washer Dryer

Because the baseline unit in this product class does not have automatic cycle termination, DOE believes that EL 1 would be achieved by inc orporating such a feature. Because the baseline unit already has a number of temperature sensors as well as electric controls, the changes required to implement an automatic cycle te rmination feature would li kely be minimal, consisting primarily of an additional temperature se nsor in the exhaust air as well as control logic reprogramming.

Because of the complex construction of the baseline combination washer/dryer, DOE believes that the design changes from EL 1 to EL 2 for vented electric c lothes dryers could not be applied to this product class. Further, for th e reasons described above for vent-less electric compact (240 V) clothes dryers, DOE believes that the EL 3 and EL 4 design changes for vented electric clothes dryers would be applied to EL 2 and EL 3, respectively, for this product class.

5-59Again, because the baseline unit already incorporates a two motor design, as well as electronic controls, the incremental manufacturin g costs will be smaller for this product class as compared to vented electric clothes dryers.

Standby Mode Construction As part of the reverse engineering analy sis, DOE investigated the design options and incremental manufacturing costs for decreasing standby power consumption. DOE developed the following design pathways for the standby levels identified in section 5.4.2.2.

DOE’s analysis suggests that SL 1 can be achieved by implementing a switch-mode power supply in place of a conventional line ar regulated control board power supply. DOE observed a number of clothes dryers which incorpora ted switching power supplies. DOE’s teardown analysis also suggests that SL 2 can be achieved by implementing a transformerless power supply along with a conventional power supply. Such a power supply design, incorporated with a “soft” power pushbutton and electromechanical relay, would provide just enough power through the transformerless power supply to maintain the microcontroller chip while the clothes dryer is not powered on. When the power button is pressed, the control logic enables a Triode for Alternating Current (Triac) to enable power to the transformer of linear power supply. Hence, the Triac isolates the linear power supply from the ma ins until it is needed to power relays, the user interface, etc. Through this means, the standby power issues typically associated with linear power supplies can be eliminated.

5.6.1.4 Cost-Efficiency Curves

Active Mode Based upon product teardowns and cost mode ling, DOE developed the following costefficiency relationships for each product class, shown in

Figure 5.6.19 through

Figure 5.6.24 and Table 5.6.9 through Table 5.6.14. For product classes for which AHAM provided data, the corresponding cost-efficiency curves are plotted as well.

5-60Figure 5.6.19 Vented Electric Standar d Clothes Dryer Cost-Efficiency Curves

Table 5.6.9 Vented Electric Standard Clot hes Dryer Incremental Manufacturing Costs

Efficiency Level (EF,

lb/kWh ) Incremental

Cost Baseline (3.01) $0 1 (3.10) $11.89 2 (3.16) $63.56 3 (3.40) $97.48 4 (4.52) $258.47

5-61Figure 5.6.20 Vented Electric Compact (120V) Clothes Dryer Cost-Efficiency Curve

Table 5.6.10 Vented Electric Compact (120V) Clothes Dryer Incremental Manufacturing

Costs

Efficiency Level (EF,

lb/kWh ) Incremental

Cost Baseline (3.13) $0 1 (3.22) $10.95 2 (3.29) $63.37 3 (3.54) $96.45 4 (4.70) $245.69

5-62Figure 5.6.21 Vented Electric Compact (240V) Clothes Dryer Cost-Efficiency Curve

Table 5.6.11 Vented Electric Compact (240V) Clothes Dryer Incremental Manufacturing

Cost

Efficiency Level (EF,

lb/kWh ) Incremental

Cost Baseline (2.90) $0 1 (2.98) $10.95 2 (3.09) $63.37 3 (3.20) $96.45 4 (4.35) $245.69

5-63Figure 5.6.22 Vented Gas Clothe s Dryer Cost-Efficiency Curves

Table 5.6.12 Vented Gas Clothes Drye r Incremental Manufacturing Cost

Efficiency Level (EF,

lb/kWh ) Incremental

Cost Baseline (2.67) $0 1 (2.75) $14.79 2 (2.85) $65.36 3 (3.02) $156.01

5-64Figure 5.6.23 Vent-less Electric Compact ( 240V) Clothes Dryer Cost-Efficiency Curve

Table 5.6.13 Vent-less Electric Compact (240 V) Clothes Dryer In cremental Manufacturing

Cost

Efficiency Level (EF,

lb/kWh ) Incremental

Cost Baseline (2.37) $0 1 (2.39) $12.35 2 (2.59) $68.36 3 (3.55) $215.71

5-65Figure 5.6.24 Vent-less Electric Combinat ion Washer/Dryer Cost-Efficiency Curves

Table 5.6.14 Vent-less Electric Combination Washer/Dryer Incre mental Manufacturing

Cost

Efficiency Level (EF,

lb/kWh ) Incremental

Cost Baseline (1.95) $0 1 (2.21) $0.81 2 (2.42) $54.04 3 (3.32) $230.17

Standby Mode Based upon the product teardowns and cost modeling, DOE developed the incremental costs associated with decreasing standby power consumption, shown in Table 5.6.15.

Table 5.6.15 Standby Power Incremental Manufacturing Cost

Standby Power Level (W) Incremental

Cost Baseline (2.0) $0 1 (1.5) $1.30 2 (0.08) $0.66

5-66Incremental Costs by IEF

As discussed in section 5.4, the clothes dr yer analysis for this rulemaking is based on the integrated metric, IEF. DOE analyzed the improvement in IEF associated both with design options that improve EF and design options that reduce standby power. DOE developed overall cost-efficiency relationships for the IEF ef ficiency levels presented in section 5.4.2.3. As noted above in section 5.4.2.3, DOE incor porated incremental standby power levels into IEF efficiency

levels where DOE determined them to be most cost effective. Table 5.6.16 through Table 5.6.21 present DOE’s estimates of incr emental manufacturing cost for improvement of clothes dryer

IEF above the baseline.

Table 5.6.16 Cost-Efficiency Relationship for Ve nted Electric Standard Clothes Dryers

Integrated Efficiency Level (IEF, lb/kWh ) Incremental Manufacturing Cost Baseline (2.96) $0 1 (3.04) $11.89 2 (3.10) $63.56 3 (3.33) $97.48 4 (3.35) $98.78 5 (3.40) $98.14 6 (4.52) $259.13

Table 5.6.17 Cost-Efficiency Relationship for Vented Electric Compact (120V) Clothes Dryers

Integrated Efficiency Level (IEF, lb/kWh ) Incremental Manufacturing Cost Baseline (3.00) $0 1 (3.08) $10.95 2 (3.15) $63.37 3 (3.37) $96.45 4 (3.41) $97.75 5 (3.53) $97.11 6 (4.69) $246.35

Table 5.6.18 Cost-Efficiency Relationship for Vented Electric Compact (240V) Clothes Dryers

Integrated Efficiency Level (IEF, lb/kWh ) Incremental Manufacturing Cost Baseline (2.79) $0 1 (2.86) $10.95 2 (2.96) $63.37 3 (3.06) $96.45 4 (3.10) $97.75 5 (3.19) $97.11 6 (4.34) $246.35

5-67Table 5.6.19 Cost-Efficiency Relationship for Vented Gas Clothes Dryers

Integrated Efficiency Level (IEF, lb/kWh ) Incremental Manufacturing Cost Baseline (2.63) $0 1 (2.71) $14.79 2 (2.80) $65.36 3 (2.97) $156.01 4 (2.98) $157.31 5 (3.02) $156.67

Table 5.6.20 Cost-Efficiency Relationship for Vent-less Electric Compact (240V) Clothes Dryers

Integrated Efficiency Level (IEF, lb/kWh ) Incremental Manufacturing Cost Baseline (2.29) $0 1 (2.31) $1.30 2 (2.37) $0.66 3 (2.39) $13.01 4 (2.59) $69.02 5 (3.54) $216.37

Table 5.6.21 Cost-Efficiency Relationship for Vent-less Electric Combination Washer/Dryers

Integrated Efficiency Level (IEF, lb/kWh ) Incremental Manufacturing Cost Baseline (1.90) $0 1 (2.15) $0.81 2 (2.34) $54.04 3 (2.36) $55.34 4 (2.42) $54.70 5 (3.31) $230.83

5.6.1.5 Manufacturer Interviews

DOE conducted interviews with residential clothes dryer manufacturers to determine appropriate efficiency levels for the preliminary analyses and to develop a better understanding of the technologies used to improve energy ef ficiency. During these interviews, DOE asked

manufacturers what max-tech ef ficiency levels would be appropriate for each clothes dryer product class. DOE also asked manufacturers what groupings of design options are used in baseline designs and what would be implemented to increase the energy efficiency in order to meet the efficiency levels proposed in section 5.4. 1.2 for residential clothes dryers. The discussion helped DOE understand what proposed design options have already been implemented and what additional design opti ons DOE should consider. In addition, DOE conducted discussions regarding issues with the DOE test procedure for clothes dryers. The discussion below represents a consolidation of the responses. DOE subsequently conducted

5-68another series of interviews with manufacturers to solicit feedback on preliminary manufacturing cost estimates DOE developed through the reverse engineering analyses.

Max-Tech Efficiency Levels

Manufacturers indicated that the current maxi mum-available EF for vented gas clothes dryers listed in the CEC product database is not achievable. Multiple manu facturers stated that the CEC product database has had errors in the values listed in the past for other products, and at least one manufacturer suggested that DOE test the maximum-available model to determine an appropriate max-tech level. As discussed in section 5.6.1.2, DOE teste d the maximum-available gas clothes dryer and determined that it did not achieve the rated EF.

Multiple manufacturers indicated that an EF of approximately 3.0 would be an appropriate max-tech value. In addition, AHAM submitted incremental manufacturing cost data, aggregated from manufacturer inputs, for the max- tech active mode efficiency level for vented gas clothes dryers proposed in th e framework document (3.02 EF).

Components That Influence Energy Efficiency

Manufacturers identified c omponents that influence energy efficiency in residential clothes dryers that are related to baseline de signs. DOE also identifie d components and design options that it believed could potentially influence en ergy efficiency in residential clothes dryers. DOE requested comment on each of these design options and their potential for increasing energy efficiency.

Manufacturers indicated that they use a single 4-pole induction motor to drive both the

drum and the blower in their base line clothes dryer. Manufac turers also use a single-element electric resistance heater for electric clothes dryers and a single-stage gas valve for gas clothes dryers. In addition, manufacturers generall y incorporate electromechanical controls into their baseline units along with some form of automatic termination control by temperature sensing.

A number of manufacturers indicated that improvements to energy efficiency can be made by implementing more efficient fan motor s in place of the standard 4-pole induction motor. Manufacturers believed that 1 to 5 percent i mprovement can be achieved using more efficient fan motors, such as electronically-commutated motors (ECM), however the costs are high.

Manufacturers also indicated that all of the ir units incorporate some form of automatic termination sensing control. Ma nufacturers stated that thermostatica lly controlled automatic

termination control with electromecha nical controls is generally the least accurate form of automatic termination sensing. Using moisture sensors along with the thermostat controlled automatic termination sensing can improve the accuracy of these systems. To increase the accuracy further, manufacture rs indicated that they would use moi sture sensing controls with thermistors, which give continuous feedb ack, along with electronic controls.

5-69At least one manufacturer indicated that addin g insulation could improve efficiency minimally. However, most manufacturers believ ed that there is no significant efficiency improvement with insulation.

A number of manufacturers indicated that modifying the air flow can improve efficiency. For example, multiple manufacturers indicated that switching the drum air flow design from front to back to a design flowing in through one side of the drum on the back and out through the other side of the back can improve efficiency 1 to 3 percent.

Manufacturers also indicated that preheating inlet air, either through the use of an air-toair heat exchanger or recirculation of process air, can improve energy ef ficiency. Manufacturers indicated varying degrees of potential improveme nts to energy efficiency associated with this design option, ranging from 1 to 12 percent.

With regards to modulating heat, manufacturers indicated that they would incorporate a modulating heater to reach differ ent efficiency levels. They also indicated that modulating gas valves are significantly more expensive than single-stage gas valves.

A number of manufacturers have indicated that they manufacture heat pump dryers for

international markets. Most ma nufacturers stated that 30 to 50 perce nt efficiency improvement is possible using heat pump technology. Manufacturers indicated that they would generally consider using a R-134a c ompressor along with tube and fin heat exchangers.

Strategies to Incre ase Energy Efficiency

Manufacturers generally supported the propose d efficiency levels for the vented dryer product classes. However, a number of manufacturers indicated that the max-available gas efficiency level above 3.44 EF (proposed in the first set of preliminary manufacturer interviews) may be difficult to achieve. Manufacturers genera lly indicated that the max-available efficiency level for vented gas dryers should be between 3.0 and 3.06 EF (90 percent of the max-available level for vented electric standard). DOE subse quently adjusted the max-available gas dryer efficiency level based on updates to the CEC database. For the vented electric compact 120V product class, at least one ma nufacturer was in agreement with the method used to develop the efficiency levels. However, other manufacture rs indicated that meeting even the baseline efficiency would be difficult.

For the vent-less electric compact 240V product class, at least one manufacturer indicated that it believed the proposed efficiency levels were appropriate. Howeve r, a few manufacturers also indicated that the proposed efficiency levels were low compared to the efficiencies achieved by the units that they manufacture.

Although manufacturers cited different design pathways for meeting the proposed efficiency levels, in general they cited the following strategies to increase energy efficiency: (1)air flow system improvements, (2) modulating heat design, (3) inlet air preheating, (4) higherefficiency motor designs, and (5) heat pump technology for electric dryers.

5-70Manufacturers indicated that air flow sy stem changes would be included in design changes to meet the proposed efficiency levels. Some manufacturers cited such changes as using direct duct heaters to provide better heatin g and minimize heat losses. Other manufacturers indicated that better air flow sealing or insulation could also be used to meet efficiency levels. Manufacturers generally indicated that air flow system changes would be incorporated as part of design changes to meet EL 1 or EL 2 for vented dryers.

Manufacturers cited modulating heat designs as a strategy to improve energy efficiency.

Some manufacturers indicated that the costs for th is design change would be 3 to 4 times higher for a gas dryer, which would require a modulating gas valve and additional controls, as compared to an electric dryer, which would use ei ther a multi-element resistance heater or a single element with modulating current. Various manufacturers indicated that they would use modulating heat as part of the design changes to meet EL 1 through EL 3 for vented dryers.

Manufacturers also indicated that when adopting a modulatin g heater, they would additionally implement improved moisture sensing and more complicated controls systems.

Manufacturers also indicated that preheating inlet air is important to consider for achieving efficiency improvements. Some manufacture rs indicated that this could be achieved by partial recirculation of the process air through the burner or heater system for all or part of the cycle. Manufacturers indicated that if they were to recirculate the proce ss air, they would add or modify lint screens to prevent lint migrati on into the heater system. Other manufacturers believed that inlet air could be pre-heated by using a heat exchanger. Manufacturers that commented they would incorporate this design option, believed that it would be used as part of the design changes to meet either EL 2 or EL 3 for vented dryers.

Manufacturers cited improved motor effic iency as a strategy for meeting the proposed efficiency levels. Most manufacturers that commented that they would incorporate improved motor efficiency stated that they would likely incorporate this into the design changes for EL 3. Manufacturers indicated that they would likely use a separate ECM motor for the fan.

Manufacturers indicated that heat pump technology would provide the largest improvement to efficiency. Most manufacturers indicated that 30 to 50 percent improvement in efficiency can be achieved with heat pump dryers. However, manufacturers that produce compact sized heat pump clothes dryers for international markets indicated that the very long cycle times would be a consumer utility iss ue for U.S. consumers as well as the much higher

initial cost of the unit.

A few manufacturers indicated that they would need to incorporate heat pump technology

to reach EL 3 for vented electric standard dryers, which would be a 13 percent improvement over the baseline EF. DOE notes that there are currently units available on the market which meet EL3 which do not incorporate heat pump technology and DOE believes that using heat pump technology can improve the efficiency beyond this point to the proposed EL 4. DOE also notes that some manufacturers indicated design changes to m eet EL 3 that did not include switching to a heat pump design.

5-71Manufacturers also noted that a number of the above mentioned design changes would require improved control systems using moi sture sensing and electronic controls.

Manufacturers indicated that for vent- less electric compact (240V) dryers, they would apply the same design changes as were used for vented electric dryers. In addition, they would consider modifications to the heat exchanger as a potential source for improving energy efficiency.

With regards to the proposed standby power leve ls for clothes dryers, at least one manufacturer commented in agreement with the proposed design changes for decreasing standby power in clothes dryers. They indicated that both incorporating a switching power supply and a transformerless power supply with a Triac to control power through the transformer are reasonable approaches to achieving standby levels 1 (1.5W) and 2 (0.08W). Again at least one manufacturer agreed that the incremental manufacturing costs associated with standby levels 1 and 2 that DOE developed through its reverse engineering analysis are appropriate.

Incremental Manufacturing Cost

In the initial set of preliminary manufac turing interviews, DOE requested feedback on whether the aggregated costs submitted by AHAM were representative of the manufacturing costs developed by each manufac turer. Most manufacturers indicated that the aggregated costs submitted by AHAM were representative of their costs for each efficiency level.

After DOE conducted the f irst round of preliminary manufacturer interviews, DOE developed incremental manufacturing cost-effic iency curves based on manufacturer inputs and reverse engineering analysis. DOE subseque ntly requested feedback from manufacturers on these incremental manufacturing cost -efficiency curves in order to refine its analysis. Manufacturers indicated that although they were not always in agreement with the design changes used to meet each efficiency level, they were generally in agreement with the incremental manufacturing cost-efficiency curves, indicating that values developed by DOE were generally within 20 percent of the values submitted by these manufacturers. Manufacturers also provided indications of the appropriateness of component pricing estimates used in DOE’s

cost model. DOE used information learned dur ing these discussions to revise its reverse engineering analysis and incr emental manufacturing costs.

Test Procedure Issues

DOE requested comment on a number of issues regarding the DOE test procedure for clothes dryers. Manufacturers indicated that they have observed test to test variation from 0.03 to

0.1 EF points for a single unit tested multiple times. At least one manufacturer indicated that latest test cloth may have some problems, showing var iations in measured EF as the test cloth is used for multiple test runs. A number of manufacture rs also indicated that variation in results can be seen within the allowable range ambient humidi ty and temperatures. Ma nufacturers stated that variations in ambient humidity had more of an effect on results than temperature. However, at

least one manufacturer indicated that the ambient conditions are difficult to maintain and it would be hard to justify tighter tolerances given the requirements of increased control.

5-725.6.2 Room Air Conditioners

The room air conditioner engineering analysis was performed by considering cost and efficiency information from multiple sources. DOE conducted its own detailed room air conditioner teardowns and estimated the manufacturing costs of observed efficiency features for current designs using HCFC-22 refrigerant. DOE also carried out energy modeling supported by manufacturing cost analysis to determine the incremental cost associated with efficiency improvements for products using R-410A. DO E also conducted interviews with room air

conditioner manufacturers to obtain greater insight into design strategies and their associated costs to improve efficiency. DOE did not rece ive aggregated industry data from AHAM for the incremental costs to achieve higher efficiency levels.

5.6.2.1 AHAM Data

In support of the room air conditioner rule making, AHAM requested incremental manufacturing cost data from its member compani es. As mentioned above, not enough responses were obtained to allow reporting to DOE. Table 5. 6.22 and Table 5.6.23 de scribe market share by product class from 2005 to 2007. A large majo rity of the shipped products are from product classes 1 through 5, products without re verse cycle and with louvered sides.

Table 5.6.22 AHAM Room Air Conditioner Product Class Market Share Data Submittal: Product Classes 1 Through 5
Without Reverse Cycle (RC) an d With Louvered Sides (LS)

Product Class 1 2 3 4 5

<6k 6

– 8k 8

– 14k 14

– 20k >20k

2005 37% 19% 30% 3% 2%

2006 23% 19% 34% 5.5% 3.9%

2007 32% 16% 36% 6% 2.6%

Table 5.6.23 AHAM Room Air Conditioner Product Class Market Share Data Submittal: Product Classes 6 through 16

Without

Reverse Cycle and

Without

Louvered

Sides With Reverse Cycle and

With Louvered Sides With Reverse Cycle and

Without Louvered Sides Casement Only Casement

Slider

<20k >20k <14k >14k

Product Class 6 - 10 11 13 12 14 15 16

2005 7% 0.7% 0.1% 0.4% 0.4%

2006 12% 1.0% 0.6% 0.6%

2007 7% **   **  0.4% **Insufficient responses were received by AHAM to allow reporting for these product classes.

Table 5.6.24 and Table 5.6.25 detail the shipment-weighted average energy efficiency of room air conditioner shipments from 2005 to 2007 by product class. Data were not provided for

5-73product classes 6, 7, 10, 13, 14, and 15. The efficiency trends for these products are mixed, with EER increasing for some product cla sses and decreasing for others.

Table 5.6.24 AHAM Room Air Conditioner Shipment Weighted Efficiency Data (EER) Submittal: Product Classes 1 through 5
Without Reverse Cycle (RC) an d With Louvered Sides (LS)

Product Class 1 2 3 4 5

<6k 6

– 8k 8

– 14k 14

– 20k >20k

2005 9.5 10.2 10.3 10.3 9

2006 9.8 10.4 10.4 10.5 9.2

2007 9.8 9.9 10.1 10.3 9.1

Table 5.6.25 AHAM Room Air Conditioner Shipment Weighted Efficiency Data (EER) Submittal: Product Classes 6 through 16
Without Reverse Cycle

and Without Louvered

Sides With Reverse Cycle and With

Louvered Sides With Reverse Cycle

and Without

Louvered Sides Casement

Slider

8

– 14k 14

– 20k <20k <14k

Product Class 8 9 11 12 16

2005 9.5 ** 10.6 9.6 9.9

2006 9.5 ** 10.5 9.6 **

2007 9.5 9.0 ** 9.5 **Insufficient responses were received by AH AM to allow reporting for these product classes.

In addition to market share by product class and shipment-weighted average energy efficiency for room air conditioners, AHAM a lso submitted data disclosing market share by efficiency level and year. These data are tabulated in appendix 5B.

5.6.2.2 Manufacturer Interviews

DOE conducted interviews with room air c onditioner manufacturers to develop a better understanding of the technologies used to improve en ergy efficiency. During these interviews,

DOE asked manufacturers what groupings of design options would be required to increase the energy efficiency in order to meet the ef ficiency levels proposed in section 5.4.1.2 for room air conditioners. The discussions helped DOE understand which design opti ons have already been implemented and which additional design opti ons DOE should consider. The discussion below represents a consolidation of the responses.

Components That Influence Energy Efficiency

Manufacturers identified the components that influence energy efficiency in room air conditioners as fans, blowers, and fan motors, heat exchanger coils, and compressors. Most

manufacturers use PSC fan motors. Some manufacturers have considered electronicallycommutated motors (ECM), which use less energy than PSC fan motors, but generally have not pursued using them because of cost.

5-74Manufacturers currently use rotary compressors in their room air conditioners, and the efficiency range of compressors available today va ries by product class. Since new products cannot use HCFC-22 starting in 2010, manufacture rs have been transitioning their room air conditioner designs to R-410A re frigerant. The range of compressors for use with R-410A refrigerant which have been fully tested and UL -approved is significantly more limited than the range of compressors which can use HCFC-22. Manufactures mentioned that the EER range for R-410A compressors currently available tops out at 10.0, as compared to 11.0 for HCFC-22 compressors. Manufacturers expected to be a ble to make up for much but not all of the

difference as a result of the better heat tra nsfer performance of R-410A. Manufacturers have not implemented variable-speed compressors because of the higher cost and because the steady conditions of the DOE test procedure do not capture the actual-use benefits of such compressors. Other compressor technologies, such as scroll or reciprocating compressors, are available only for higher capacity room air c onditioners but are generally not used due to size, weight, and/or

vibration issues.

Strategies to Incre ase Energy Efficiency

Manufacturers consider material cost, shi pping cost, and weight as key design parameters. Manufacturers cited the following strategies to increase energy efficiency: (1) heat exchanger coil improvements or face area increase, (2) air system design improvement to increase air flow, (3) use of higher-efficiency fa n motors, (4) higher-eff iciency compressors, and (5) subcooler coils.

Manufacturers cited compressors as a key strategy to increase energy efficiency. However, as mentioned above, compressors vendors are not currently offering as full a range of compressor EER levels with R-410A compressors as ha ve been available for HCFC-22. This is expected to change over the next few years, but at this point it is not clear what level of compressor performance will be available wh en the new standards for room air conditioner efficiency take effect.

Manufacturers are emphasizing heat exchan ger coil improvements to increase energy efficiency, since this design option offers the most potential for improvement. Further increases in efficiency are typically only possible via increasing the coil area. Larger coils require more metal, which manufacturers cited as a concern due to high material prices. Also, as coils grow, the chassis may have to grow as well. If the unit size and we ight increase past a certain point, consumer utility is impacted. For larger capacity products, window sizes won’t allow further size increases. Fewer products can fit in a shipping container, which results in higher per-unit shipping costs.

Manufacturers mentioned that maximizing a ir flow is also an important consideration in achieving efficiency improvements. This may involve re ducing fin density or coil depth, using more powerful fans and/or blowers, and paying closer attention to minimizing losses in the air flow passages. However, more powerful fans can have a detrimental impact on consumer utility by making the room air conditioner noisier. Finall y, while both higher efficiency PSC motors

5-75and subcooling coils were cited as having the potential to improve efficiency, the overall impact of these design options is relatively small.

5.6.2.3 Product Teardowns

DOE tore down 21 room air condit ioners across 6 product classes to identify design options, and their associated costs, that can be us ed to raise EER. As best as possible, DOE selected products of similar nominal capacity but varying efficiencies. Figure 5.6.25 shows the efficiency ranges of the selected products. The efficiency ranges for the products selected from product classes 1, 3, and 5 cover the range of efficiency leve ls of available products. For product classes 3 and 8, products were selected at ca pacity levels of both 8,000 Btu/h and 12,000 Btu/h.

Note: The product class 2 unit did not undergo full teardown and uses R-410A refrigerant. All other products use HCFC-22 refrigerant. The 12,000 Btu/h 9.5 EER product cla ss 3 product was advertised as being a through-the-wall product (product class 8).

Figure 5.6.25 Efficiency Range of Room Air Conditioner Teardowns

After the room air conditioner teardowns, D OE grouped costs into key materials categories. Figure 5.6.26 shows the breakdown of material costs for a typica l HCFC-22 baseline product class 3 room air conditioner , as generated from DOE’s BOM. Note that the refrigeration system, heat exchangers, and fan components (components that largely determine energy

5-76consumption) make up 63 perce nt of the material costs. Fi gure 5.6.27 shows the various costs comprising a typical baseline product class 3 room air conditioner’s full production cost. Depending on the manufacturer and the product ion volume, the depreciation costs may vary from those shown in the figure, which assumes a “ green- field” site.

5-77Figure 5.6.26 Baseline HCFC-22 Product C lass 3 (12,000 Btu/h) Room Air Conditioner Material Cost Distribution ($157 total)

5-78Figure 5.6.27 Baseline HCFC-22 Product Clas s 3 12,000 Btu/h Room Air Conditioner Full Production Cost Distribution ($195 total)

The manufacturing cost model was used in subseque nt analysis to determine the cost of room air conditioner designs incorporating series of design options to incr ease efficiency. The results of these analyses are discussed in section 5.6.2.7.

5.6.2.4 Energy Modeling

DOE conducted energy modeling in order to determine what design options are required to achieve increased efficiency levels in room air conditioners using R-410A refrigerant. The energy model developed as part of the previous room air conditioner energy conservation standard rulemaking was upgraded for this purpose. The original room air conditioner energy model was an adaptation of the Oak Ridge National Laboratory Mark III Heat Pump program for modeling of room air conditioner cooling perfor mance and is described in the 1997 TSD from the previous room air conditioner energy conservation standards rulemaking. 4 Additional modifications made during this rulemaking to upgrade the program for modern room air conditioners include the following.

Revision of the heat exchanger performance mod els to reflect more recent correlations for airside heat transfer and pre ssure drop performance. This includes correlations for the slit fins typically used in today’s room air conditioners as well as for microchannel heat exchangers.

5-79Incorporation of property routines for other refrigerants, including R-410A.

Development of a platform to allow r unning the program in the Microsoft Windows operating system.

The modified program is called MarkN, and it is explained in greater detail in the MarkN manual provided with the program.

Because MarkN does not incorporate calculation of the performa nce of fans or blowers or the air pressure drops associated with c omponents other than the heat exchangers, some modeling external to the program was conducted to properly a ccount for system changes that impact air flows. DOE developed airside models that calculated the pressure losses within the

room air conditioner of a ir passages, flow transitions, inlets, and outlets, and that incorporated heat exchanger pressure drop results from Ma rkN for both the evaporator and condenser. The

airside models also included models of the fan or blower performance. With the airside model used in conjunction with MarkN, DOE was able to properly account for the impacts on air flow and fan motor shaft power associated with the analyzed design modifications.

Fan performance information was generally not available for the fans and blowers of the teardown models that were analyzed. Performance data for similar fans and blowers were obtained from vendors. DOE adjusted the availa ble fan and blower performance information using the fan laws from the 2008 ASHARE Handbook, HVAC Systems and Equipment 5 , in order to approximate the performance of the components in the products that were analyzed.

Further information on the airside models is available in appendix 5D.

The energy use for each of the teardown units was modeled and compared to the rated performance for these units to verify the validity of the upgraded energy model. Inputs for the individual models were based on the design detail s determined during tear down of the products. Some of the system operating para meters were determined from energy testing, as discussed in section 5.6.2.5. Evaporator air flow was set equ al to the rated evaporator air flow. Hot wire

anemometer measurements of c ondenser air flow and fan motor power input measurements were made prior to teardown to provide model input for these parameters. Compressor performance input data were obtained from compressor vendors.

The results of this comparison of energy mod el results and rated performance of the teardown units are shown in Figure 5.6.28 below. The figure shows that both capacity and efficiency of the products were well predicted by the energy model. Of these products, only the 6,000 Btu/h 12.0 EER room air conditioner used R- 410A refrigerant. All other units used HCFC22 refrigerant.

5-80Figure 5.6.28 Comparison of Energy Mo deling Results with Rated Air Conditioner

Performance

After calibration of the energy models by comparison with rated performance data as discussed above, DOE used the energy model to dete rmine the energy impact of conversion to R410A refrigerant. DOE conducted this analysis fo r all of the teardown pro ducts using HCFC-22 refrigerant, assuming only drop-in of an R-410A compressor with no other adjustments for the new refrigerant. Performance data of the R-410A compressors was obtained from compressor vendors. The R-410A drop-in analyses are compar ed with the baseline HCFC-22 analyses in Figure 5.6.29 below. The models generally show a reduction in EER in the range of 0 to 15
percent.

Figure 5.6.29 Energy Modeling Results for R-410A Drop-In

Further energy analysis was conducted on designs modified by a series of design options in order to determine the energy efficiency improvement possible with each of these design options. This analysis was performed for the six baseline-efficiency products of product classes

5-811, 3, 5, and 8. For most of these products, some improvement was required for the initial R-410A design in order to achieve EER levels meetin g the current DOE energy standards. Additional improvements allowed examination of the inc remental cost for efficie ncy improvements for R410A room air conditioners. The results of the design option energy modeling analyses are

discussed in section 5.6.2.7 below.

5.6.2.5 Energy Testing

Four of the teardown units were energy tested prior to teardown. The energy test results were used to verify performance of some of the higher-efficienc y products. The comparison between rated and tested performance is shown in Figure 5.6.30 below. Test results for three of the units were close to the rated performance, while the results of the fourth were not.

*This product was advertised as bein g for through-the-wall installations ( i.e. product class 8),

but it had louvered sides. Figure 5.6.30 Room Air Condition er Energy Test Results

The energy testing conducted with additional instrumentation to allow recording of system temperatures. These measurements were used during energy modeling to help in

calibration of the models with test results. Refrigerant te mperatures were approximated by measurement of tube surface temperatures with thermocouples adhered to the tubes and externally insulated. The addit ional system measurements included:

� compressor discharge;

� condenser mid (a return bend ro ughly halfway between the condenser inlet and outlet, a location where the refrigerant is expected to be at saturated conditions);

� condenser outlet or subcooler outlet (for those units having a subcooler);

� evaporator inlet;

� evaporator outlet; and

� suction.

5.6.2.6 R-410A Conversion Costs

DOE determined, from manufac turer and vendor interviews, that there were intrinsic

costs associated with the conversion from HFC-22 to R- 410A. From these interviews, DOE

5-82determined that these cost increases include increa sed compressor costs, incre ased costs of the switch to polyolester (POE) oil, and increased refrigerant cost. DO E considered the impacts of each effect when calculating the cost of ma nufacturing for each room air conditioner.

Compressor Costs

From interviews with manufacturers and compressor vendors, D OE determined that rotary compressors designed for use with R-410A carr ied a higher price than compressors for HCFC-22 refrigerant. R-410A compressors require a thi cker shell due to the higher pressures of R-410A, which is a key factor in the cost incr ease. Using the feedback from a variety of interviews, DOE used a compressor cost premium of 10 perc ent for R-410A compressors. This cost is for an R-410A compre ssor matching the capacity and EER of the R-22 compressor it replaces.

Compressor Oil Switch

Due to miscibility issues, HFC refrig erants generally cannot be used in compressors lubricated with mineral oils, which have been us ed with HCFC-22. POE oils are being used in R410A rotary compressors. DOE calcul ated the additional cost of oil based on the price difference between mineral oil and POE oils. The cost of the compressor oil switch was added separately, because the 10 percent compressor cost increase mentioned above is based on purchasing compressors without oil. The prices of mineral oil and POE oil were based on manufacturer and oil vendor inputs.

Refrigerant Switch

During interviews, manufacturers mentioned that R-410A costs more than HFC-22. DOE

calculated the cost increase associa ted with the refrigerant based on the HCFC-22 charge of the

teardown units. The costs of R-410A and HFC-22 refrigerants were based on inputs from manufacturers and retail sources of refrigerant.

DOE added the impacts of these three factors to calculate the tot al cost increase of the R410 drop-in conversion. Table 5.6.26 below summarizes these costs for each analyzed product class. Note that the designs associated wi th these costs have lower EER than the baseline, and hence additional costs need to be added to represe nt the cost increase to maintain the baseline efficiency with an R-410A product. These additional c osts were determined as the first step in the analysis of design options for improvement of efficiency, and they are discussed in section

5.6.2.6.

5-83Table 5.6.26 Manufacturing Cost Incre ase for Drop-In Conversion to R-410A

Product Class Total Costs Due to Refrigerant Switch

PC 1 $3.92 PC 3 (8,000 Btu/h Capacity) $5.47 PC 3 (12,000 Btu/h Capacity) $7.49

PC 5 $13.70 PC 8 (8,000 Btu/h Capacity) $5.77 PC 8 (12,000 Btu/h Capacity) $7.95

5.6.2.7 Cost-Efficiency Curves

To generate cost-efficiency curves, DOE ex amined both design options that influence EER and design options that influence standby or off mode energy use.

After the screening analysis and further elimination of design options discussed in section 5.2.2, DOE retained the design options list ed in Table 5.6.27 below for improvement of efficiency.

Table 5.6.27 Retained Design Options for Room Air Conditioners

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. Microchannel heat exchangers Component Improvements

6. Improved blower/fan motor efficiency

7. Improved compressor efficiency Standby Power Improvements

8. Switching Power Supply

DOE determined the energy savings associated with each of these design options using energy modeling. DOE determined the cost i mpact per option using the manufacturing cost model established during the teardown analysis , obtaining additional input on component costs from vendor inquiries and manufacturer interviews. Details regarding the approach to savings

and cost calculations for each of the desi gn options are discussed below in greater detail.

Increased Frontal Coil Area

5-84The energy and manufacturing cost models directly calculate the benefit and cost of increasing frontal coil area. DOE considered a number of variants on this design option, depending on the details of the baseline product under consideration.

In some of the baseline products, the evaporator width was limited unnecessarily by placement of the electronic control board next to the evaporator, preventing its expansion along the face of the unit. In many cas es, there was sufficient space in alternative locations for the controls, such as above the evap orator adjacent to the vent. One variant of this design option that DOE examined was placing the controls above the evaporator, rather than beside it, thus freeing space to ex pand the evaporator. Some teardown units already incorporated the placement of the c ontrols above the evaporator, especially the high-efficiency units. It did not appear to have an impact on utility.

Increasing the physical size of the room air conditioner was c onsidered for product classes 1, 3, and 5. For product class 8, size increase was not considered

— since much of

the market for room air conditioners without louvered sides involves installation in existing wall sleeves, size increase for product classes 6 through 10 (including 8), 12, and 14 are not possible. The sizes of the prod uct class 1, 3, and 5 baseline products in DOE’s test sample are compared in Figure 5.6.31 with a d istribution of product sizes of baselineefficiency room air conditioners from the database developed by DOE from the CEC, ENERGY STAR, and AHAM databases desc ribed in chapter 3. The comparisons show that the analyzed products can be made larger without exceeding the size of other current baseline-efficiency products. . DOE drew a similar conclusion when comparing weights of the analyzed product designs with the weights of other baseline products in the

database. With an overall unit size increase, the frontal areas of both the evaporator and

condenser can be increased. The examined size increases are summarized in Table 5.6.28

below.

For some products, it may be possible to add a bend to the condenser coil in order to fit more coil frontal area within an existing cha ssis size. DOE examined this approach for the product class 1 unit and for both product class 8 units. The condenser coil bend was a

feature observed in some teardown units.

5-85Figure 5.6.31 Size Distribu tions of Baseline-Efficiency Room Air Conditioners

Table 5.6.28 Size Increases Examined During Room Air Conditioner Design Option Analysis

Design Description Width (inches (in)) Height (in) Depth (in) Weight (lb)

Product Class 1

Baseline

First Size Increase

Second Size Increase 15.5

18.5

19.69 11.75

12.5

13.63 12

14

17.72 38.6

42.7

46.8 Product Class 3, 8,000 Btu/h

Baseline

First Size Increase

Second Size Increase 18.5

19.3

22.5 12.5

15.3

15.3 14

18

23.6 49.4

55.7

63.6 Product Class 3, 12,000 Btu/h

Baseline

First Size Increase

Second Size Increase 19.63

24.63

26.38 13.75

17.5

17.5 19.63

22.25

26.75 76.5

81.2

87.6

Product Class 5

Baseline

First Size Increase

Second Size Increase 26

27.75

29.81 17.69

17.94

22.38 28.41

30.94

30.94 129.2

136.4

156.5

5-86DOE believes increases in coil frontal ar ea and package size are among the primary factors contributing to EER improvements in the higher-efficiency teardown units for product classes 1, 3, and 5. The sizes and weig hts of these units are shown in Table 5.6.29 below.

Table 5.6.29 Sizes and Weights of Teardown Units for Product Classes 1, 3, and 5

Design Description Width (in) Height (in) Depth (in) Weight (lb)

Product Class 1 Baseline 1, 9.7 EER Baseline 2, 9.7 EER

10.7 EER

11 EER 15.5

17.28

18.91

18.5 11.75

11.16

12.46

12.5 12

7.28

14.69

14 38.6

36.5

48.2

44.4 Product Class 3, 8,000 Btu/h Baseline, 9.8 EER

10.8 EER

11.4 EER 18.5

18.59

25.94 12.5

12.75

15.94 15.5

16.34

27.38 49.4

49.4

108 Product Class 3, 12,000 Btu/h Baseline, 9.8 EER

10.8 EER

11.8 EER 19.58

23.63

25.94 13.75

15

22.25 19.63

22.25

27.38 73

78.6

108.8

Product Class 5 Baseline, 8.5 EER

9.4 EER 26

26.5 17.69

18.63 28.41

25 132

135.2

Added Shipping Costs for Chassis Size Increases

The room air conditioner reverse-enginee ring included documentation of the packaging used for shipping the product, and additional accessories (remote control, window installation kit, bracing). As the chassis expands, the surrounding packaging also increase s in size. The costs

associated with all of these increa ses are part of the calculated inc remental cost for the efficiency improvements. Most of the shipp ing material packaging c ost is the cost of the surrounding

cardboard box.

Most room air conditioners are shipped from overseas, and manufacturers mentioned the added shipping costs associated with larger chassis sizes. DO E calculated the cost of shipping to a U.S. distribution facility based on the size of the room air conditioner be ing shipped; the cost is

determined based on the volume of the unit. This cost was reported separately from the manufacturing production cost (MPC). DOE expects that th e manufacturer markup does not apply to this cost because manufacturers indicate d that many room air conditioners are shipped by retailers. Hence, in determining the incremental cost associated with efficiency improvements, the shipping cost increase would be added to the incremental manufacturer sales price (MSP).

The shipping cost was determined as follows. DOE estimated the total shipping costs for a standard shipping container, base d on interviews with manufacturers and quotes from shipping companies. The costs include shi pping from the factory to a U.S. distribution facility. The number of units per container wa s calculated by volume, and divided by the cost of shipping to

5-87determine the cost of shipping per unit. For design options that involved increase in chassis size, DOE calculated incremental shipping costs to ac count for the larger size. The cost estimate including distribution within the U.S. is considered to be conservative, because part of this cost may already be included in the typical retailer ma rkup, which has not be reduced to account for separate consideration of part of the shipping cost.

Increased Depth of Coil

DOE examined increasing the depth of the eva porator and/or condenser. Energy impacts were determined using the energy model, and cost impacts were determined using the manufacturing cost model. DOE de termined that increasing coil depth beyond two tube rows generally is not effective in increasing EER. Most room air conditioners use heat exchangers with two tube rows, although some have more rows. However, the DOE analysis shows that the airflow reduction or fan power increase associated with increases in coil depth often negates the benefits of the additional heat exchanger surface area.

Increased Fin Density

DOE examined increases in fin density for all of the products. Energy impacts were determined using the energy model, and cost impa cts were determined using the manufacturing cost model. DOE considered a maximum fin density of 22 fins per inch (FPI). In some cases, increasing fin density improves performance. For many cases, the airflow resistance of the

additional fins leads to reduced airflow and/or hi gher fan power which negates the benefit of the increased heat exchanger surface area. Many unit s already use high fin densities, so increased fin density often results in minimal or no gains. La stly, high fin densities have been mentioned by manufacturers as having potential detrimenta l effects on long-term unit efficiency, since cleaning coils with high fin densities is very difficult.

Add Subcooler to Condenser Coil

DOE examined the use of a subcooler for all room air conditioners. Energy impacts were determined using the energy model, and cost impacts were determined using the manufacturing

cost model. DOE used a subcooler exit temperature of 95 °F, based on feedback provided by

manufacturers. 4 In all cases, the subcooler made a small improvement in efficiency, but was highly cost-effective. Inspecti on of the teardown units revealed that many high-efficiency units placed the subcooler within the condenser plenum. DOE determined that the addition of a subcooler to a unit would not require an y chassis size increase.

In selecting the appropriate subcooler leng th for each product class, DOE considered the subcoolers from the teardown units. In each product class, the highest-efficiency unit contains a subcooler. The length of this subcooler provided the basis for the length of the subcooler added for a product of the same capacity. In some cas es DOE determined th at the chosen subcooler length was excessive for the baseline cha ssis size. DOE reduced the selected length and performance of the subcooler in these case s. DOE maintained a fixed subcooler length with subsequent chassis size increases.

5-88Microchannel Heat Exchangers

Performance modeling of microchannel h eat exchangers is included in the upgraded room air conditioner energy model. Information provided from vendors indicates that, in most cases, this technology is not suitable for evaporators because (1) the geometry is not suitable for quick drainage of condensate from the heat exch anger surface; and (2) uniform refrigerant distribution into the many parallel tubes is not assured. Therefore, microchannel heat exchangers were considered only for condensers. Use of this technology resulted in a small efficiency improvement in most of the analyses. Microc hannel condenser increme ntal manufacturing costs were calculated based on prices provided by a vendor for two representative sizes, one suitable for a 5,000 Btu/h room air conditioner and the other suitable for a 24,000 Btu/h unit, assuming high-volume production. In addition to purchase p rice, the costs also incorporate the cost of brazing two pieces of copper tubing to the all- aluminum microchannel heat exchanger, since many purchasers do not have the capability of br azing copper to aluminum and such fabrication would represent an additional st ep in the manufacturing process.

The sizes and cost estimates of the microchannel heat exchanger designs considered in the analysis are presented in Table 5.6.30 below. For the most part, the costs are an order of magnitude greater than that of any of the oth er design options conside red. The table also shows the modeled efficiency improvements calculated for this design option. The improvements were

low or zero.

Table 5.6.30 Microchanne l Condenser Costs

Room Air Conditioner Capacity (Btu/h) Condenser Core

Dimensions (Height x Length, in) Condenser Core Depth (in) Cost EER Increase

Benefit from

Baseline 5,000 11.25 × 15.25 1 $75 0.3
8,000 12.75 × 17.25 1 $85

- 12,000 16 × 21.63 1 $110

- 24,000 16.37 × 22 1 $115 0.1

Improved Fan/Blower Motor Efficiency

Room air conditioners almost exclusively use double-shafted PSC motors to power the condenser fan and evaporator blower. DOE conside red improved motor efficiency as a design option, in the form of high efficiency PSC mot ors and brushless DC (BLDC) motors. DOE

considered the cost of the motors as a function of motor type , shaft power, and efficiency, although only one efficiency level was considered for BLDC m otors. DOE obtained cost data from vendors, both for room air conditioner motors and for single-shaft motors with similar power output and speed used in other applications. DO E selected a typical range of motor shaft power rating for each product class it analyzed, based on the motors used in the teardown units, and sought information about similar motors at hi gher efficiencies. The selected shaft power

levels are shown in Table 5.6.31 below.

5-89Table 5.6.31 Motor Power Rating by Product Capacity Room air conditioner capacity (Btu/h) Fan Motor Shaft Power Rating (W)
<6,000 25-35 8,000 to 13,999 60-75
>20,000 150-200

DOE selected a motor efficiency of 50 perc ent for the PSC motors of baseline room air conditioner. This was consistent with the motors in the teardown units, as well as the information obtained during manufacturer intervie ws. DOE selected a peak PSC motor efficiency of 70 percent for the analysis.

BLDC motors are a more efficient alterna tive to PSC motors, and BLDC motors are used in similar applications, such as packag ed terminal air conditioner s (PTACs). DOE obtained information about BLDC motors from motor vendors, motor catalogs, and discussions with room

air conditioner manufacture rs. Reported BLDC motor efficiencies were in the range 75 percent to 90 percent. DOE selected an efficiency level of 80 percent for the analysis.

DOE examined PSC motor prices from a wide variety of motor vendors. DOE conducted analysis on this motor data to establish a r obust correlation for motor cost based on motor characteristics including efficiency, shaft power, weight, current, and voltage. The assessment included single-shafted and double-shafted PSC mot ors intended for HVAC applications. DOE found the strongest correlation between motor price and weight, and used this relationship as the basis for calculating the incremental costs for PSC motor efficiency improvements. Figure 5.6.32 below shows the calculated cost of increasing the eff iciency of a PSC motor from 50 percent to 70 percent as a function of motor shaft power output, for shaft outputs from 20 W to 100 W. This range included motors for product classes 1, 3 and 8. For the product class 5 baseline motor, with a rated shaft output of 200 W, DOE extra polated the cost of the motor from the smaller motor

sizes. Further information on the assessment of PSC mot or costs is availa ble in appendix 5D.

5-90Figure 5.6.32 Cost Differential for Increasing PSC Motor Efficiency from 50% to 70%

DOE also compiled pricing and size information on BLDC motors from motor vendors and catalogs. DOE found prices for BLDC m otors with the same motor shaft output as the PSC motors found in the reverse engineering units, and ca lculated the cost of replacing the baseline PSC motors with the BLDC motors. Figure 5.6.33 below shows the calculated cost of replacing a

baseline PSC motor with a BLDC motor.

5-91Figure 5.6.33. Cost Differential for Replacing a Baseline PSC Motor with a BLDC Motor.

Some manufacturers raised concerns regarding the use of BLDC motors, stating that they are physically much larger than PSC motors and thus may not fit into the small space allowed in

a room air conditioner. Table 5.6.32 shows the characteristi cs of a typical 70 W PSC motor, and the characteristics of a typical 70 W BLDC motor observed by DOE. These ranges are derived from motor vendor catalog data. The data show that the BLDC motor has greater weight and length than the comparable double-shafted PSC motor.

Table 5.6.32 Comparison of a typical range of sizes for a 70W PSC Double-Shafted Motor

and a 70W BLDC Motor Typical Characteristics Double-Shafted PSC BLDC Typical Efficiency 50% 80% Weight 8

– 10 lbs. 12 lbs.

Outer Diameter 3.75

– 5.0 in 1.73

– 2.63 in Motor Length (w/o Shaft) 3.0

– 4.25 in 4.5

– 6.39 in

Improved compressor efficiency

5-92DOE conducted the engineering analysis base d on use of R-410A refrigerant, since all

room air conditioners will re quire use of this new refrigerant before any new energy conservation standard becomes effective. DOE sought info rmation on the performance of R-410A rotary compressors of varying efficiency levels for all of the products under analysis. In many cases, the range of efficiency for which vendors were willing to provide performance data was limited. Conducting the analysis generally required knowl edge not just of design point capacity and

EER

— DOE requested performance data for a representative range of evaporating and condensing conditions, as required for input into the energy model. In some cases, the trends of compressor performance as a function of operat ing conditions were extra polated from the trends exhibited by a compressor of the same refrigerant of nearly the same capacity. For product class 5, DOE also analyzed scroll compressors as a design option. The EER and capacity of the compressors for which DOE o btained performance data are illustrated in

Figure 5.6.34 below. As can be seen, there are data for many more HCFC-22 compressors than for R-410A rotary compressors. The EER ratings of the R-410A compressors are not only generally lower than that of an HCFC -22 rotary compressor with a similar capacity, but exhibit a much more limited EER range ( i.e. , HCFC-22 compressor E ER levels range from

9.0 to 11.2 near 5,000 Btu/h nominal capacity, whereas the R-410A compressor EER range is roughly 9.0 to 10.0). The chart shows that reduc tion in the EER when switching to R-410A compressors is greater for lower capacities than for higher capacities. The chart also shows that the use of scroll compressors does not improve efficiency for the capacities of interest for room

air conditioners.

5-93Figure 5.6.34 Compressor Performance Data

The relationship between R-410A compressor c ost and baseline-efficiency room air conditioner capacity that DOE used in the analysis is illustrated in

Figure 5.6.35 below. This relationship was developed based on information collected during past rulemakings, discussions with manufacturers, a nd cost information provided by compressor vendors. It includes the 10 percent cost pre mium for R-410A compressors discussed in section

5.6.2.6. The figure is based on room air condition er capacity, and not compressor rating point capacity.

5-94Figure 5.6.35 R-410A Compressor Cost

Concerns about the potential size and we ight increase, and higher cost, exists in considering the use of a scroll compressor in a 24,000 Btu/h room air conditi oner. The baseline HCFC-22 compressor and R-410A scroll compressors that could be c onsidered for product class 5 are compared in Table 5.6.33 below. The smaller-capacity scroll compressor is relevant because it provides sufficient capacity for the room air conditioner after energy-savings changes such as improvement in condenser and evapora tor performance are implemented. The heights of the scroll compressors are close to 3 inches less th an the heights of the product class 5 units which were part of the tea rdown work (see section 5.6.2.3 above ). The size and weight data show that design of a high efficiency product using the smaller scroll compressor would be acceptable.

Table 5.6.33 Size and Weight of Applicable Rotary and Scroll Compressors for a 24,000

Btu/h Room Air Conditioner

24,000 Btu/h

HCFC- 22 Rotary Compressor 24,000 Btu/h

R-410A Scroll

Compressor 21,000 Btu/h

R-410A Scroll

Compressor Shell Height (in) 13 15.14 15.28

Shell Diameter (in) 5.5 5.5 5.5 Weight (lb) 44 63 47

5-95Standby Mode and Off Mode

DOE identified and analyzed only one option for reducing standby and off mode energy

use

– changing from a transformer-based power supply to a switching power supply. DOE conducted energy measurements of electronic boar ds, and determined that the total inactive mode power for a typical baseline control board is roughly 1.4 W, and that the transformer consumes about 75 percent of this power. DOE concluded that the main source of power consumption in inactive mode for a room air conditioner is the power supply, as shown in Table

5.6.34. The measurements reported in this table were made by disconnecting more loads for the successive measurements, thus showing that nearly 1 W of the 1.32 W associated with the standby mode for this unit represents the transfor mer loss (the transformer loss could actually be a larger portion of the 1.32 W, since disconne cting the loads as indicated reduces power supplied by the transformer, and thus could also be reduc ing the its loss in the successive measurements).

Table 5.6.34 Standby Energy Consumption by Component Example Stand-by Energy Brea kdown for Electronic Board Components Energized Power Consumption (W)

User Interface Board + Control Board 1.32

Control Board 1.28

Transformer 0.96

Two of the teardown units with elec tronic control boards used switch-mode power supplies, an alternate technology to the traditional linear regulated power supply. The switching power supply replaces the traditional power supply with a more complex circuit board and a much smaller transformer. The two switching power supply units consumed roughly 0.7 W.

DOE obtained conversion c ost information for switching power supplies for cell phone technology, based on similar production volumes and power levels as for room air conditioner control board power supplies. The incr ease in direct material costs for converting to a switchmode power supply based on this information is approximately $1.00.

Cost-Efficiency Curves based on EER

DOE developed two sets of c ost-efficiency curves for each product class/capacity combination analyzed fully: A curve based on the HCFC-22 teardown pro ducts. This curve was generally incomplete, since a full range of EER was not purchase d for each product class. For one of the product classes, two sets of HCFC-22 curves were developed, since two sets of products ( i.e. , products at two efficiency levels made by each of two manufacturers) were purchased. A curve based on the analysis of R-410A designs that is described in detail in this chapter.

5-96The cost-efficiency curves based on EER are shown in Figure 5.6.36 through Figure

5.6.41 below. The cost axis of these charts represents MSP plus shipping cost. Note that AHAM did not receive a sufficient number of responses regarding costs from manufactures to allow aggregation of this data for submission to DO E. Hence, there is no AHAM data to allow comparisons. All of these curves are based on design configuration, i.e. each separate point in the plot represents a different design configurat ion. Note that the plots show the reduction in EER and the cost impact of the conversion to R- 410A, including the drop in EER for initial “drop

- in” of the new refrigerant. The data in all of these plots are for products with a “baseline” standby power level of 1.4 W.

Each cost-efficiency curves developed for R-410A is plotted next to a cost-efficiency curve for HCFC-22. The efficiency levels on the R-410A curves were calculated using the energy model, while the efficiency levels on the HCFC-22 curves represent the efficiency levels of the products selected for reverse engineering. The manufacturing costs for both sets of curves are based on the cost model developed from DOE’s reverse engineering work.

The charts show that, although the HCFC-22 cu rves are shifted to a lower cost and higher initial EER, there is generally good agreement in slope between curves for the HCFC-22 products and the modeled R-410A curves. The slope of the HCFC-22 curve for the product class 8 12,000 Btu/h product is in reverse because of some of the design details associated with the baseline product of this group. This baseline was one of the fe w teardown products observed which had heat exchangers with four rows of tubes (most of the products, even the higher EER models, had heat exchangers with two rows of tube s). The use of deeper heat exchangers resulted in unusually high costs for this product.

5-97Figure 5.6.36 Product Class 1 Cost-Efficiency Curve

5-98Figure 5.6.37 Product Class 3 - 8,000 Btu/h Capacity Cost-Efficiency Curve

5-99Figure 5.6.38 Product Class 3 - 12,000 Btu/h Capacity Cost-Efficiency Curve

5-100Figure 5.6.39 Product Class 5 Cost-Efficiency Curve

5-101Figure 5.6.40 Product Class 8 - 8,000 B tu/h Capacity Cost-Efficiency Curve

5-102Figure 5.6.41 Product Class 8 - 12,000 Btu/h Capacity Cost-Efficiency Curve

Incremental Costs by IEER

The previous section discusses costs associa ted with increase of the active mode efficiency, measured in EER. As discussed in section 5.4, the analysis for this rulemaking is based on the integrated metric, IEER. DOE analyzed the improvement in IEER associated both with design options that improve EER and design options that reduce standby power. DOE developed overall cost-efficiency relationships for IEER by combining these analyses. In this overall analysis, DOE chose to implement the design options in order of decreasing costeffectiveness. The reduction in standby power ha d cost-effectiveness between that of the best and worst active mode design options. This is illustrated fo r the product class 1 analysis in Figure

5.6.42 below. The plot shows the incremental IEER improvement of the design option divided by incremental manufacturing production cost (MPC) associated with the design option.

5-103Figure 5.6.42 Comparison of th e Cost-Effectiveness of Active and Standby Mode Design Options

As discussed above, DOE determi ned that the incremental cost for reducing inactive mode power consumption from 1.4 W to 0.7 W is $1.00. Table 5.6.35 below summarizes this

incremental cost.

Table 5.6.35 Room Air Conditioner Cost-Standb y/Off Mode Power Relationship
Standby Level Power (W) Incremental Cost

Baseline 1.4 $0

1 0.7 $1.00

Table 5.6.36 through Table 5.6.41 present DOE’s estimates of increm ental cost in terms of MPC for improvement of room air conditioner IEER above the baseline. The tables also present the calculated shipping cost at each efficiency level, based on the shipping package size.

The first level of each table reflects the calculated IEER of a unit with a baseline EER rating and a standby power consumption of 1.4 W. The cost for this level represe nts the estimated cost associated with regaining the curr ent standard EER level with the new refrigerant. DOE

calculated the costs for each IEER level base d on appropriate selection of active mode and standby mode design options. In cases where the IEER efficiency level does not coincide with the IEER determined for the design configura tion directly analyzed with energy and manufacturing cost modeling, DOE took the following approach. If the next design option could be partially applied, DOE interpol ated between costs and IEER le vels calculated for the nearest design configurations. This approach applied to hea t exchanger or chassis size increases, PSC motor efficiency improvement, and addition of a subcooler. In cases where the next design

5-104option could not be partially applied, the f ull cost of the design option was applied. This approach applied to increase in the number of heat exchanger circuits, change in heat exchanger tube size, and switch to BLDC motor technology.

Table 5.6.36 Room Air Conditioner Cost-Efficiency Relationships for Product Classes 1

Product Class 1: Without Reverse Cycle, With Louvered Sides, < 6,000 Btu/h

Efficiency

Level IEER MPC Increase Shipping Costs

Baseline 9.52 $7.65 $4.18

1 10.1 $12.18. $5.31

2 10.6 $18,22 $6.25

3 11.1 $27.19 $7.64

4 11.6 $37.30 $8.39

5 12.0 $44.10 $8.39

Table 5.6.37 Room Air Conditioner Cost-Efficiency Relationship for Product Class 3

– 8,000 Btu/h Capacity Unit

Product Class 3

– 8,000 Btu/h: Without Reverse Cycle, With Louvered Sides, 8,000 - 13,999 Btu/h Efficiency

Level IEER MPC Increase Shipping Costs

Baseline 9.69 $9.58 $6.32

1 10.3 $18.65 $8.61

2 10.8 $27.12 $11.65

3 11.3 $38.38 $14.63

4 11.5 $43.12 $14.63

Table 5.6.38 Room Air Conditioner Cost-Efficiency Relationship for Product Class 3

– 12,000 Btu/h Capacity Unit

Product Class 3

– 12,000 Btu/h: Without Reverse Cycle, With Louvered Sides, 8,000 - 13,999 Btu/h Efficiency

Level IEER MPC Increase Shipping Costs

Baseline 9.72 $11.20 $14.46

1 10.3 $17.57 $15.89

2 10.8 $24.25 $17.64

3 11.3 $42.64 $21.79

4 11.5 $114.06 $21.79

5-105Table 5.6.39 Room Air Conditioner Cost-Effici ency Relationships for Product Class 5

Product Class 5: Without Reverse Cycle, With Louvered Sides,

≥ 20,000 Btu/h Efficiency

Level IEER MPC Increase Shipping Costs

Baseline 8.47 $23.78 $24.79

1 9.0 $37.47 $27.88

2 9.4 $52.84 $32.66

3 9.8 $75.30 $36.46

4 10.0 $104.34 $36.46

Table 5.6.40 Room Air Conditioner Cost-Efficiency Relationship for Product Class 8

– 8,000 Btu/h

Product Class 8

– 8,000 Btu/h: Without Reverse Cycle, Without Louvered Sides, 8,000

– 13,999 Btu/h Efficiency

Level IEER MPC Increase Shipping Costs

Baseline 8.41 $6.14 $12.26

1 8.9 $8.62 $12.26

2 9.3 $10.51 $12.26

3 9.8 $21.70 $12.26

Table 5.6.41 Room Air Conditioner Cost-Efficiency Relationship for Product Class 8

– 12,000 Btu/h

Product Class 8

– 12,000 Btu/h: Without Reverse Cycle, Without Louvered Sides, 8,000

– 13,999 Btu/h Efficiency

Level IEER MPC Increase Shipping Costs

Baseline 8.44 $8.77 $12.26

1 8.9 $13.28 $12.26

2 9.3 $20.21 $12.26

3 9.8 $35.94 $12.26

DOE consolidated product cla sses 3 and 8 by averaging the results of the 8,000 Btu/h costs and the 12,000 Btu/h costs. These averages were used in the subsequent LCC analysis. The final averages for product classes 3 and 8 are shown in Table 5.6.42 and Table 5.6.43. below.

5-106Table 5.6.42 Room Air Conditioner Cost-Efficiency Relationship for Product Class 3

– Average

Product Class 3

– Average: Without Reverse Cycle, With Louvered Sides, 8,000

– 13,999 Btu/h Efficiency

Level IEER MPC Increase Shipping Costs

Baseline 9.71 $10.39 $10.39

1 10.3 $18.11 $12.25

2 10.8 $25.68 $14.65

3 11.3 $40.51 $18.21

4 11.5 $78.59 $18.21

Table 5.6.43 Room Air Conditioner Cost-Efficiency Relationship for Product Class 8

– Average

Product Class 8

– Average: Without Reverse Cy cle, Without Louvered Sides, 8,000

– 13,999 Btu/h Efficiency

Level IEER MPC Increase Shipping Costs

Baseline 8.44 $7.45 $12.26

1 8.9 $10.95 $12.26

2 9.3 $15.36 $12.26

3 9.8 $28.82 $12.26

Extrapolation of Addition al Product Classes

The incremental cost data for room air conditioner product classes not directly analyzed is discussed in this section. The methodology for estimating the incremental costs associated with efficiency increase s for these product classes is described below.

DOE first established efficienc y levels based on the EER metric for the product classes that were not directly analyzed. These effi ciency levels were de termined based on information about existing room air conditioners of these product classes, and ex trapolation from efficiency levels of the product classes that were directly analyzed. The active mode efficiency levels are presented in Table 5.6.44 through Table 5.6.46.

5-107Table 5.6.44 EER Efficiency Levels for Product Classes 2, 4, 6, 7

Product

Class 2: Without Reverse Cycle, With Louvered Sides, 6,000-7,999 Btu/h 4: Without Reverse Cycle, With Louvered Sides, 14,000-19,999 Btu/h 6: Without Reverse Cycle, Without

Louvered Si des,

<6,000 Btu/h 7: Without Reverse Cycle, Without Louvered Sides, 6,000-7,999 Btu/h Efficiency

Level Description Level EER Level EER Level EER Level EER

DOE

Standard 1 9.7 1 9.7 1 9.0 1 9.0

Gap Fill 2 10.2 2 10.2 2 9.5 2 9.5 Energy Star 3 10.7 3 10.7 3 9.9

CEE Tier 1 4 11.2

CEE Tier 2 5 11.6

Gap Fill 4 10.4

Maximum

Available 6 12.0 4 11.0 3 9.7 5 10.8

Table 5.6.45 EER Efficiency Levels for Product Classes 9, 10, 11, 13

Product

C lass 9: Without Reverse Cycle, Without Louvered Sides, 14,000-19,999 Btu/h 10: Without Reverse Cycle, Without Louvered Sides, >=20,000 Btu/h 11: With Reverse Cycle, With Louvered Sides,

<20,000 Btu/h 13: With Reverse Cycle, With Louvered Sides, >=20,000 Btu/hr Efficiency

Level Description Level EER Level EER Level EER Level EER

DOE

Standard 1 8.5 1 8.5 1 9.0 1 8.5

Gap Fill 2 9.0 2 9.0 2 9.5 2 9.0 Energy Star 3 9.4 3 9.9 3 9.4

Gap Fill 4 10.0

Maximum

Available* 5 10.5 3 9.1 4 10.2 *

*No products of this product class from the databases we re found for sale. Maximum database EER was 9.4

Table 5.6.46 EER Efficiency Levels for Product Classes 12, 14, 15, 16

Product

Class 12: With Reverse Cycle, Witho ut Louvered Sides,

<14,000 Btu/h 14: With Reverse Cycle, Without Louvered Sides, >=14,000 Btu/h 15: Casement Only 16: Casement

- Slider

Efficiency

Level Description Level EER Level EER Level EER Level EER

DOE

Standard 1 8.5 1 8.0 1 8.7 1 9.5

Gap Fill 2 9.0 2 8.4 2 9.2 2 10.0 Energy Star 3 9.4 3 8.8 3 9.6 3 10.5

Maximum

Available 4 9.5 4 9.1 9.5 10.5

5-108DOE conducted its analysis on the basis of the integrated IEER metric, so DOE next established efficiency levels based on IEER for the se product classes. DO E selected efficiency levels rounded to the nearest tenth, except for the baseline levels des cribed in section 5.4.1.3. The levels were chosen to correspond to the EER efficiency levels discussed in the tables above as closely as was feasible. DOE calculated these IEER efficiency levels by first selecting a representative capacity for each product cl ass (shown in Table 5.6.50, a nd derived from the average capacity of representative identified units) and an appropriate stand-by power level for each efficiency level. At baseli ne efficiency level, DOE assumed baseline standby power. DOE adjusted the standby power to SL 1 at EL 2 ba sed on results that were determined for product classes that were directly analyzed. DOE the n calculated the IEER efficiency levels using the EER efficiency levels presented above using the method described in section 5.4.2.3. DOE adjusted the max-tech IEER in certain cases to maintain the appropriate IEER differentials

between baseline and max-tech levels. For product classes for which cost increments were interpolated, DOE adjusted the ma x-tech IEER to match the lower of the two values for the product classes from which it was interpolated. For product classes for which cost increments were extrapolated, DOE adjusted the max-tech IEER to maintain the differential of the product

class from which it was ex trapolated. In certain cases, the max- tech IEER was further adjusted to account for different sets of design options and capacities. The selected levels are summarized in Table 5.6.47 through Table 5.6.49 below.

Table 5.6.47 IEER Efficiency Levels for Product Classes 2, 4, 6, 7

Level IEER (Btu/h-W)

2: Without Reverse Cycle,

With Louvered Sides, 6,000-7,999 Btu/h 4: Without Reverse Cycle, With Louvered Sides, 14,000 - 19,999 Btu/h 6: Without Reverse Cycle, Without Louvered Sides,

<6,000 Btu/h 7: Without Reverse Cycle, Without Louvered Sides, 6,000- 7,999 Btu/h

Baseline 9.56 9.65 8.85 8.88

1 10.1 10.2 9.4 9.4

2 10.6 10.7 9.9 9.9

3 11.1 11.2 10.3 10.3

4 11.4

Table 5.6.48 IEER Efficiency Levels for Product Classes 9, 10, 11, 13

Level IEER (Btu/h-W)

9: Without Reverse

Cycle, Without Louvered Sides, 14,000-19,999 Btu/h 10: Without Reverse Cycle, Without Louvered Sides, >=20,000 Btu/h 11: With Reverse Cycle, With Louvered Sides,

<20,000 Btu/h 13: With Reverse Cycle, With Louvered Sides, >=20,000 Btu/hr

Baseline 8.46 8.47 8.94 8.47

1 9.0 9.0 9.5 9.0

2 9.5 9.5 10.0 9.4

3 10.5 9.8

4 10

5-109Table 5.6.49 IEER Efficiency Levels fo r Product Classes 12, 14, 15, 16

Level IEER (Btu/h-W)

12: With Reverse

Cycle, Without Louvered Sides,

<14,000 Btu/h 14: With Reverse Cycle, Without Louvered Sides, >=14,000 Btu/h 15: Casement Only 16: Casement

- Slider

Baseline 8.43 7.97 8.62 9.41

1 9.0 8.5 9.2 10.0

2 9.4 9.0 9.7 10.5

3 9.8 10.2 11.0

Methodology

DOE used interpolation and extrapolation methods, based on the IEER levels of the analyzed product classes, to calculate incremental costs for the remaining product classes. The methodology used to calculate incremental costs for each remaining product class is detailed

below.

For product classes 2 and 4, DOE calculated incremental costs by interpolating data for the neighboring product classes, i.e. the data for product classes 1 and 3 were used to calculate the incremental costs for product class 2. DOE carried out this interpolation based on representative capacities for the product classe s, which were calculated based on the average capacity of products in the assembled database of room air conditioners desc ribed in Chapter 3. The representative capacities are pres ented in Table 5.6.50 be low. The interpolation for incremental cost was two-dimensional, based on both capacity and IEER increase as compared with the IEER of the initial R-410A design.

Table 5.6.50 Representative Capacities for Room Air Conditioner Product Classes

Product

Class Capacity (Btu/h) Product

Class Capacity (Btu/h)

1 5,100 9 16,300

2 6,400 10 25,900

3 10,200 11 13,200

4 16,900 12 9,600

5 25,100 13 25,100*

6 5,100 14 21,800

7 6,500 15 9,300

8 10,300 16 9,700 Sources: CEC, ENERGY STAR, and AHAM databases as of August 2008, with review of manufacturer and retailer websites to remove products no longer active. *No active products were identified for this product class. Representative capacity is set equal to the same representative capacity for product class 5 (the difference between these product classes is reverse cycle for product class 13).

For product classes 6, and 7, DOE extrapolated the incremental costs for product class 8 to the higher and lower capacity product classe s based on the variation of incremental cost with capacity exhibited by product classes 1 and 3. For product classes 9 and 10, DOE carried out an extrapolation based on the variation of incremental cost with capacity of product classes 3 and 5,

5-110but DOE limited the extent of the possible increase in IEER based on room air conditioner size, since the through-the-wall products of product cl asses 6 through 10 cannot increase is size.

For product classes 11 and 13, DOE carried out an interpolation based on results for product classes 1 through 5. DOE assumed for this calculation that the use of reverse cycle for these product classes does not affect the cost of improving cooling mode efficiency. DOE carried out a similar interpolation for pr oduct classes 12 and 14 based on the results for product classes 6 through 10.

Finally, for product classes 15 and 16, DOE carried out an interpolation based on the results for product class 3, with a limitation on extent of the possible IEER increase based on room air conditioner size, due to the limited potential for growth of these product classes.

The results of the extrapolations are tabula ted in Table 5.6.51 through Table 5.6.53. Table

5.6.36 through Table 5.6.43 shows the incremental cost data from which the extrapolated incremental costs were developed.

Table 5.6.51 Extrapolated Incre mental Cost Data for Product Classes 2, 4, 6, and 7

Product Class 2 Product Class 4 Product Class 6 Product Class 7

IEER Cost IEER Cost IEER Cost IEER Cost

9.56 $8.34 9.65 $16.41 8.85 $5.48 8.88 $5.98

10.1 $12.99 10.2 $26.81 9.4 $7.54 9.4 $8.33

10.6 $19.14 10.7 $37.89 9.9 $10.91 9.9 $14.70

11.1 $28.99 11.2 $69.21 10.3 $20.02 10.3 $22.00

11.4 $43.66

Table 5.6.52 Extrapolated Incremental Cost Data for Product Classes 9, 10, 11, 13

Product Class 9 Product Class 10 Product Class 11 Product Class 13

IEER Cost IEER Cost IEER Cost IEER Cost

8.46 $13.72 8.47 $23.75 8.94 $13.09 8.47 $23.78

9.0 $44.99 9.0 $99.45 9.5 $22.01 9.0 $37.47

9.5 $155.27 9.5 $373.52 10.0 $32.52 9.4 $52.84

10.5 $53.36 9.8 $75.30

10 $104.34

Table 5.6.53 Extrapolated Incremental Cost Data for Product Classes 12, 14, 15, 16

Product Class 12 Product Class 14 Product Class 15 Product Class 16

IEER Cost IEER Cost EER Cost EER Cost

8.43 $7.18 7.97 $19.47 8.62 $10.39 9.41 $10.39

9.0 $11.83 8.5 $76.19 9.2 $18.11 10.0 $18.11

9.4 $18.09 9.0 $280.31 9.7 $26.34 10.5 $26.34

9.8 $27.57 10.2 $103.57 11.0 $103.57

Further Information.

5-111The incremental cost data for active mode de sign options are detailed further in appendix 5D. The appendix also provides inc remental cost data for both the integrated metric (IEER) and non-integrated metric (EER).

5-112REFERENCES

1 T Richter. 2005. Op. cit

.

2 Kao, J. “Energy Test Result s of a Conventional Clothes Dr yer and a Condenser Clothes Dryer ,” National Institute of Standards and Technology, Gaithersburg, MD, 1998

.

3 For information on American Metals Market, please visit: www.amm.com

.

4 2005 ASHRAE Handbook: Fundamentals. ASHRAE, Atlanta, GA 2005.

4 U.S. Department of Energy

– Office of Energy Efficiency and Renewable Energy. Technical Support Document for Energy Conservation Standards for Room Air Conditioners: September 1997. Washington, D.C. Available at: www.eere.energy.gov/buildings/appli ance_standards/residential/room_ac.html

5 2008 ASHRAE Handbook: Fundamentals. ASHRAE, Atlanta, GA 2008

.

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