CHAPTER 5. ENGINEERING ANALYSIS

TABLE OF CONTENTS

5.1 INTRODUCTION ........................................................................................................... 5-1
5.2 PRODUCT CLASSES ANAL YZED .............................................................................. 5-1
5.3 EFFICIENCY LEVELS ................................................................................................... 5-3
5.3.1 Baseline Efficiency Levels .............................................................................................. 5-4
5.3.2 Incremental Efficiency Levels ......................................................................................... 5-7
5.3.2.1 Portable Dehumidifier Product Classes ......................................................... 5-7
5.3.2.2 Whole- Home Dehumidifier Product Classes ................................................. 5-8
5.4 METHODOLOGY OVERVIEW .................................................................................. 5-10
5.4.1 Review of Previous Technical Support Documents and Models ................................... 5-10
5.4.2 Manufacturer Interviews ................................................................................................ 5-11
5.4.3 Product Testing .............................................................................................................. 5-11
5.4.4 Product Teardowns ........................................................................................................ 5-11
5.4.4.1 Selection of Units ......................................................................................... 5-12
5.4.4.2 Generation of Bill of Materials .................................................................... 5-12
5.4.4.3 Cost Structure of the Spreadsheet Models ................................................... 5-13
5.4.4.4 Cost Model and Definitions ......................................................................... 5-14
5.4.4.5 Cost Model Assumptions ............................................................................. 5-15
5.5 ANALYSIS AND RESULTS ........................................................................................ 5-15
5.5.1 Manufacturer Interviews ................................................................................................ 5-15
5.5.1.1 Product Classes ............................................................................................ 5-16
5.5.1.2 Design Features of Current Baseline Products ............................................ 5-16
5.5.1.3 Proposed Incremental Efficiency Levels ..................................................... 5-16
5.5.1.4 Design Options Required to Meet Each Efficiency Level ........................... 5-16
5.5.1.5 Performance at Reduced Ambient Temperatures ........................................ 5-17
5.5.1.6 Impact on Consumer Utility ......................................................................... 5-17
5.5.1.7 Installation and Repair Costs as a Function of Efficiency ........................... 5-17
5.5.2 Product Testing .............................................................................................................. 5-17
5.5.2.1 Product Selection ......................................................................................... 5-18
5.5.2.2 Test Approach and Results .......................................................................... 5-18
5.5.3 Product Teardowns ........................................................................................................ 5-21
5.5.3.1 Baseline Construction .................................................................................. 5-21
5.5.3.2 Design Options to Reach Higher Efficiency Levels .................................... 5-22
5.5.4 Numerical Model ........................................................................................................... 5-28
5.5.4.1 Summary ...................................................................................................... 5-28
5.5.4.2 An alysis Method .......................................................................................... 5-28
5.5.5 Cost Estimates ................................................................................................................ 5-30
5.5.5.1 Baseline Cost Estimates ............................................................................... 5-32
5.5.5.2 Incremental Cost Estimates .......................................................................... 5-32

5-iLIST OF TABLES

Table 5.3.1.1 Dehumidifier Baseline Unit Efficiencies Based on EISA 2007 Standards ........... 5-4 Table 5.3.1.2 Proposed Portable Dehumidifier Baseline Capacities and Efficiencies

................ 5-5
Table 5.3.1.3 Whole- Home Dehumidifier Baseline Efficiencies

................................................ 5-6 Table 5.3.2.1 Portable Dehumidifier Efficiency Levels at 80 ° F................................................. 5-7 Table 5.3.2.2 Proposed Portable Dehumidifier Efficiency Levels for the Preliminary Analysis................................................................................................................ 5-8

Table 5.3.2.3 Whole- Home Dehumidifier Efficiency Levels at 80 ° F ........................................ 5-9 Table 5.3.2.4 Proposed Whole- Home Dehumidifier Efficiency Levels for the Preliminary Analysis.............................................................................................................. 5-10 Table 5.4.4.1 Major Manufacturing Processes .......................................................................... 5-13 Table 5.5.5.1 Baseline Dehumidifier Manufacturing Cost Distribution .................................... 5-32 Table 5.5.5.3 Incremental Dehumidifier Manufacturing Costs at Higher Efficiencies ............. 5-32

LIST OF FIGURE S Figure 5.4.4.1 Manufacturing Cost Assessment Stages ............................................................. 5-13 Figure 5.5.2.1 M easured EF at 80 ° F and 65 ° F for Portable Dehumidifiers with Capacities Up to 75 pints/day at 80 ° F .............................................................. 5-19 Figure 5.5.2.2 Measured EF at 80 ° F and 65 ° F for Portable Dehumidifiers with Capacities Greater than 75 pints/day at 80 ° F .................................................... 5-19 Figure 5.5.2.3 Measured EF at 80 ° F and 65 ° F for Whole- Home Dehumidifiers .................... 5-20 Figure 5.5.4.1 R-410A Compressor Performance Chara cteristics ............................................. 5-30 Figure 5.5.5.1 R- 410A Compressor Cost from Room Air Conditioner Direct Final Rule Analysis.............................................................................................................. 5-31

5-iiCHAPTER 5. ENGINEERING ANALYSIS

5.1 INTRODUCTION

After conducting the screening analysis, the U.S. Department of Energy (DOE) performed an engineering analysis based on the remaining design options. The engineering analysis consists of estimating the energy consumption and costs of dehumidifiers at various levels of increased efficiency . This section provides an overview of the engineering analysis (section 5.1 ), discusses product classes (section 5.2 ), establishes baseline and incremental efficiency levels (section 5.3 ), explains the methodology used during data gathering ( section 5.4 ) and discusses the analysis and results (section 5.5).

The primary inputs to the engineering analysis are baseline information from the market and technology assessment ( c hapter 3 of th is preliminary technical support document ( TSD )) and technology options from the scree ning analysis ( chapter 4). Additional inputs were determined through teardown analysis and manufacturer interviews. The primary output of the engineering analysis is a set of cost

- efficiency curves . In the subsequent markups analysis (c hapter 6 ), DOE
deter mined customer ( i.e. product purchaser) prices by applying distribution markups, sales tax and contractor markups. After applying these markups, the cost

- efficiency curves serve as the input to the building energy

- use and end

- use load characterization ( chapter 7), 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) the 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 increase s; and/or (3) the reverse-engineering or

cost -assessment approach, which involves a “bottom- up” manufacturing cost assessment based
on a detailed bill of materials (BOM) derived from teardowns of the product or equipment being analyzed . Deciding which methodology to use for the engineering analysis depends on the covered product, the design options under study, and any historical data that DOE can draw on.

5.2 PRODUCT CLASSES ANALYZED

The Energy Policy Act of 2005 (EPACT 2005), Pub. L. 109-58 (42 U.S.C. 6291–6309), amended the Energy Policy and Conservation Act (EPCA) of 1975, Pub. L. 94-163 (42 United States Code (U.S.C.) 6291–6309) to establish energy conservation standards for dehumidifiers manufactured as of October 1, 2007. (Section 135(c)(4)) These standards specified five product
classes:

• 25.00 pints/day or less;

5-1• 25.01–35.00 pints/day;

• 35.01–54.00 pints/day;

• 54.01–74.99 pints/day; and

• 75.00 or more pints/day.

The Energy Independence and Security Act of 2007 (EISA 2007), Pub. L. 110-140 ( EISA 2007), in section 311(a)(1), amended EPCA to prescribe a new set of standards for dehumidifiers, which took effect on October 1, 2012. DOE codified the EISA 2007 standards at 10 CFR 430.32(v)(2). 74 FR 12058 (Mar. 23, 2009). These updated standards consolidated the two smallest product classes (25.00 pints/day or less and 25.01 – 35.00 pints/day) and subdivided the 35.01–54.00 pints/day product class into two product classes as follows:

• Up to 35.00 pints/day;

• 35.01 to 45.00 pints/day;

• 45.01 to 54.00 pints/day;

• 54.01 to 75.00 pints/day; and

• Greater than 75.00 pints /day

.

In the framework document for this rulemaking, DOE proposed maintaining these product classes. In response to comments, DOE also considered consolidating all portable products less than 75 pints /day into one product class, with efficiency levels determined from an equation relating efficiency as a function of capacity. While there is a general trend between product capacity and efficiency, DOE does not expect an equation to accurately reflect the capacity

- efficiency relationship because it does not believe there is an inherent single relationship between capacity and efficiency . Rather, these relationships are also driven by different manufacturers’ range of product chassis sizes. DOE is aware tha t manufacturers typically offer multiple products over a range of capacities, but these products are generally
constructed on one or two standardized chassis . The se standard ized cases may limit a manufacturer’s ability to optimize blower or heat exchanger configuration for a particular capacity, and significant changes in efficiency may require a manufacturer to move to a larger

case

.

Therefore, DOE expects manufacturers to reach an efficiency limit within a given case size for products at a certain capacity , although each manufacturer’s threshold for moving to a larger case size may be different . By maintaining product classes over a range of capacities,
DOE can consider standards uniquely for each product class, taking into consideration the ability
that manufactu rers have to adjust capacity within a given case in order to meet the minimum energy conservation standards. Moving to a single portable dehumidifier product class with an equation-based approach may force manufacturers to limit the range of products available on the market, or require a substantial investment to establish new production lines for product classes in which their existing range of chassis sizes would not allow the standards to be met. For these

reason s, DOE maintained in this p reliminary analysis the portable dehumidifier product classes
that are the basis of the current dehumidifier standards , although as discussed later in this section the capacity ranges were adjusted to account for proposed changes in DOE’s test procedure.

5-2In the framework document for this rulemaking, DOE noted that whole-home units generally use similar dehumidification technologies to portable units, but are designed to operate in a ducted installation. 77 FR 49739 (Aug. 17, 2012). To address the impacts of ducting on whole-home dehumidifier performance, DOE proposed a definition and test procedure for
whole-home dehumidifiers in a test procedure notice of proposed rulemaking (NOPR) published
in the Federal Register on XXXX ( XXX Test Procedure NOPR)

. CITE

. The proposed definition
in the XXX Test Procedure NOPR specif ies that a whole

- home dehumidifier is a dehumidifier
that is de signed to be installed with ducting to deliver return process air to its inlet and to supply conditioned process air from its outlet to one or more locations in the conditioned space. CITE

. Testing in support of the whole- home test ing methodology proposed in the XXXX Test
Procedure NOPR showed that the pressure restrictions imposed by a representative ducted configuration impact the performance of whole-home units such that a whole-home dehumidifier would not be able to achieve the same efficiency as portable units with the same capacity . In addition, whole-home dehumidifiers must be designed with larger blowers and motors to accommodate the pressure restrictions inherent with ducting, thus further reducing energy efficiency. Due to these performance differe nces , DOE considered whole-home dehumidifiers as a separate product class for this analysis.

DOE further divided the whole -home product class into two separate product classes by
case volume : (1) less than or equal to 8.0 cubic feet (ft 3 ) and (2) and grea ter than 8.0 ft 3 . During interviews, manufacturers indicated that various installation locations

, including attics, crawls spaces, utility closets, and others, impose case size restrictions for whole-home dehumidifiers. These spaces each impose different size restrictions on the dehumidifier floor footprint and
overall case volume. Th e proposed product class case volume differentiation is intended to capture the various applications for these whole-home products where i nstallation location may impose certain size restrictions and associated performance restrictions. Based on teardowns and market research, DOE concluded that 8 .0 ft 3 is an appropriate threshold case size for models that represent different utility in terms of installation location.

5.3 EFFICIENCY LEVELS

For dehumidifiers, energy conservation standard levels are c urrently defined by the energy factor (EF) for each product class. However, section 310 of EISA 2007 amended EPCA to require that the test procedure f or dehumidifiers be amended to include measurement of standby mode and off mode energy use, taking into consideration the most current versions of
Standards 62301 and 62087 of the International Electrotechnical Commission (IEC). a EPCA, as amended by EISA 2007, also required that any final rule establishing or revising a standard for a

a The most current version is IEC Standard 62301, “Household electrical appliances

– Measurement of standby power”, Second Edition, 2011. IEC Standard 62087, “Methods of measurement for the power consumption of audio, video, and related equipment,” Second Edition, 2008

- 2010, is not applicable to this rulem aking. IEC standards may be purchased online at www.iec.ch

.

5-3covered product, adopted after July 1, 2010, shall 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))

The DOE dehumidifier test procedure established in a final rule published on October 31, 2012, and presently codified at 10 CFR part 430, subpart B, appendix X (Appendix X b ), includes a measure of standby mode energy use, based on the methods in IEC Standard 62301. 77 FR 65942. Appendix X defines an integrated energy factor (IEF) metric that combines the active mode energy consumption with low-power mode energy consumption, which includes standby mode or off mode energy consumption. The annual combined low-power mode energy consumption is calculated based on an annual hourly usage assumption for all identified low

power modes. The low-power modes identified in Appendix X are off mode or inactive mode,
and off- cycle mode.

In accordance with the EISA 2007 requirements, this analysis was conducted using efficiency levels based on IEF, which accounts for dehumidifier standby mode and off mode

energy use.

5.3.1 Baseline Efficiency Levels

Typically, a baseline unit is a unit that just meets current energy conservation standards and provides basic consumer utility. DOE analyzed the baseline units for each product class in the engineering analysis , and the subsequent LCC and PBP analyses. To determine energy savings and changes in price, DOE compared more energy- efficien t units to the baseline unit.

Table 5.3.1.1 summarizes the October 1, 2012 prescribed by EISA 2007. Each energy efficiency level is expressed as a minimum EF, which is defined in liters per kilowatt-hour (L/kWh).

Table 5.3.1.1 Dehumidifier Baseline Unit Efficiencies Based on EISA 2007 Standards Dehumidifier Capacity EF ( L /kWh) 35.00 pints/day or less 1.35
35.01

– 45.00 pints/day 1.50
45.01

– 54.00 pints/day 1.60
54.01

– 75.00 pints/day 1.70 75.01 pints/day or more 2.50

b The final rule published on October 31, 2012 established this test procedure as Appendix X1. In a subsequent final rule published on DATE , DOE removed the dehumidifier test procedure codified at that time at 10 CFR part 430, subpart B, appendix X, and redesignated the appendix established by the October 2012 final rule as Appendix X.

CITE

.

5-4However, as described above, the analysis for this rulemaking must consider standby mode and off mode energy consumption. Accordingly, DOE conducted its analysis on efficiency levels defined by IEF rather than EF. In addition to considering standby mode and off mode
energy use, t he XX X Test Procedure NOPR proposes adding a measure of energy use in an additional active mode, fan-only mode, in which the fan remains active after the relative humidity setpoint has been reached and the compressor is inactive. ( CITE ). The proposed IEF calculation replaces the measure of off

- cycle mode energy consumption with a measure of fan

only mode energy consumption for units capable of operating in fan

- only mode.

The XXX Test Procedure NOPR also proposed a modification to the active mode test conditions required in Appendix X. In response to public comments regarding the inapplicability

of the current 80 degrees Fahrenheit ( ° F) dry- bulb test condition , DOE conducted additionalresearch regarding the typical ambient conditions under which residential portable and wholehome dehumidifiers operate. In its analysis, DOE investigated regional and time-of- year usage patterns as well as typical installation l ocations within the home. Based on this information and analyses of climate and soil temperature data

, DOE determined that the average annual operating temperature is approximately 65 °F for the representative geographic regions and months of the

year for dehumidifier us ag e. DOE’s analysis also confirmed that the existing 60

- percent relative humidity condition is appropriate

. These result s for ambient temperature and humidity are consistent with the conditions specified in the “Low Temperature Test” in ANSI /AHAM DH -1-
2008 “Dehumidifiers” , which DOE believes manufacturers may already be conducting. Therefore, the XXX Test Procedure NOPR proposed reducing the ambient dry-bulb temperature

from 80 ° F to 65 ° F while maintaining the same relative humidity of 60 percent. CITE

.

DOE conducted extensive testing at this reduced ambient temperature condition on both portable and whole-home dehumidifiers and observed the associated impacts to both capacity
and I EF. On average, capacity and I EF decreased by 35 percent and 25 percent, respectively, when compared to the 80 ° F ambient test condition.

Based on the conversion from EF to IEF, and on the proposed amendments in the XXX
Test Procedure NOPR, DOE developed adjusted product classes and I EF baseline efficiency
levels at both the 80 °F and 65 ° F ambient conditions. Because the performance reduction from
80 °F to 65 ° F is not linear with capacity , the converted capacity and efficiency levels are not directly proportional to those at 80 °F.

Table 5.3.1.2 Proposed Portable Dehumidifier Baseline Capacities and E fficiencies Capacity at 80 ° F (pints/day) Capacity at 65 ° F * (pints/day) I EF at 80 ° F ( L

/kWh) I EF at 65 ° F * ( L

/kWh)
35.00 or less 20.00 or less 1.05 0.77
35.01

– 45.00 20.01

– 30.00 1.16 0.80
45.01

– 54.00 30.01

– 35.00 1.29 0.94
54.01

– 75.00 35.01

– 45.00 1.35 1.00
75.01 or more 45.01 or more 2.44 2.07 * Capacity and IEF used for the preliminary analysis beyond the engineering analysis

5-5As shown in Table 5.3.1.2 , the baseline IEF values at 80 ° F for the product classes up to 75.00 pints/day are on average approximately 20 percent lower than the baseline EF values due to the additional standby mode, off mode , and fan -only mode energy consumption. Because units
with a fan -only mode have a lower IEF than those without fan-only mode, DOE proposes the
baseline IEF based on units with fan -only mode. DOE observed that th e impacts of adding

stan dby mode or off mode energy consumption w ere within the rounding error of the overall IEF
value for portable units with a fan -only mode , so the entire decrease from EF to IEF is
attributable to fan -only mode energy consumption . DOE did not observe fan-only mode for products in the 75.01 pints/day (as measured at 80 °F) or more product class, so the baseline IEF values for that product class adjust the current baseline EF using the maximum standby mode and off mode power observed for that product class in DOE’s test sample.

As discussed in section 5.2

, DOE considered units that ship with ducting collars and are intended by manufacturers fo r ducted operation to be classified separately as whole

- home dehumidifiers. DOE further separated this product type into two product classes based on case size. A s part of the XXX Test Procedure NOPR, DOE proposed a representative and repeatable
method for testing these whole-home units with ducting installed. CITE

. DOE found that ducting generally decrease s capacity and efficiency of these units when compared with the unducted test setup in Appendix X. In determining appropriate baseline levels for the who le -home product classes, DOE considered the effects of the ducted install ation as proposed in the XXX Test
Procedure NOPR in addition to the other changes associated with IEF discussed above. Table

5.3.1.3 presents the proposed baseline levels for the two whole-home product classes at 80 ° F

and 65 ° F.

Table 5.3.1.3 Whole- Home Dehumidifier Baseline Efficiencies
Product Class (Case Volume) IEF at 80 ° F ( L

/kWh) IEF at 65 ° F * ( L

/kWh)
Less than or equal to 8 .0 ft 3 1.90 1.10

Greater than 8 .0
ft 3 2.50 1.68

* IEF used for the preliminary analysis beyond the engineering analysis

DOE observes that the impact of the reduced ambient temperature on IEF is greater for whole-home dehumidifiers than for portable units. IEF decreased by 33 percent for whole-home dehumidifiers greater than 8 .0 ft 3 and decreased by 42 percent for whole- home units less t han or equal to 8.0 ft 3

.

5-65.3.2 Incremental Efficiency Levels

5.3.2.1 Portable Dehumidifier Product Class es

DOE analyzed several efficiency levels for portable dehumidifiers, and obtained
incremental cost data at each of these levels

. DOE first identified potential IEF levels based on the integration of standby mode, off mode, and fan-only energy use into current EF levels based on the existing test procedure. Table 5.3.2.1 includes the analyzed efficiency le vels based on the

80 ° F ambient condition and the reference source of each level for the portable product class es

.

Table 5.3.2.1 Portable Dehumidifier Efficiency Levels at 80 ° F

Efficiency
Level Efficiency Level Source Integrated Energy Factor Efficiency Levels ( L /kWh )

35.00 pints/day
or less* * 35.01

– 45.00 pints/day 45.01

– 54.00 pints/day 54.01

– 75.00 pints/day 75.01 pints/day

or more

Baseline Baseline 1.05 1.16 1.29 1.35 2.44

1 Baseline with no Fan

- only Mode (ENERGY STAR* for 75.01 pints/day or more) 1.50 1.50 1.60 1.70 2.80

2 ENERGY STAR (Gap Fill for 35.00 or less, 35.01

– 45.00 pints/day, and 75.01 pints/day or more) 1.70 1.70 1.85 1.85 3.50

3 Gap Fill (ENERGY STAR for 35.00 or less, and 35.01

– 45.00 pints/day, Maximum Available for 75.01 pints/day or more) 1.85 1.85 1.95 1.95 4.2

4 Maximum Available 1.93 1.93 2.06 2.06 N/A

* ENERGY STAR qualification criteria effective October 1, 2012, require all dehumidifiers less than 75 pints per day to have an EF of at least 1.85 L /kWh. U nits with 75 .01

– 185 pints/day capacity must have an E F of at least 2.80

L /kWh, while d ehumidifiers with a capacity greater than 185 pints/day are excluded.
** Although the DOE s tandard is 1.40 for dehumidifiers of 35.00 pints/d ay or less, a baseline efficiency level of
1.50 is used based units available on the market and similarity to the 35.01

– 45.00 pints/day product class.

For the product classes with up to 75 pints/day capacity at 80 °F, DOE analyzed four incrementally mo re efficient levels beyond the baseline. The first level above the baseline for capacities up to 75 .00 pints/day assumes a modification in the control scheme to remove fan

only mode. DOE observed test units in all product classes that operated with no fan -only mode. These units cycled off the fan along with the compressor when the humidity control setpoint was

met. DOE observed that t he two lowest capacity product classes achieved the same baseline IEF performance without fan-only mode; therefore, Effic iency L evel (EL) 1 was set at 1.50 for both

5-7of these product classes . The baseline units without fan -only mode for the higher capacity product classes had higher IEF’s, as required by the current DOE Standards. EL 1 for these product classes reflect s th ese higher efficiencies

.

DOE considered the current ENERGY STAR level s as one of the higher efficiency levels for each product class

. For the two lowest capacity product classes, the ENERGY STAR qualification level represents a large jump in efficiency from the baseline without fan -only mode, so DOE used a gap

- fill level for EL 2 and used the ENERGY STAR qualification level as EL 3. For the three higher capacity product classes, the ENERGY STAR level represents EL 2. DOE considered a gap- fill as EL 3 for these product classes before the maximum available at EL 4.

EL 4 is based on the maximum efficiency that is currently commercially available (which DOE used as a proxy for the maximum technologically feasible level) as determined from data contained within the California Energy Commission (CEC), DOE Compliance Certification Management System (CCMS), and ENERGY STAR product databases.

Table 5.3.2.2 shows the adjusted capacity ranges and efficiency levels for each portable dehumidifier product class under the proposed 65 ° F test condition. The adjusted IEF values

reflect the average decr eases in IEF that DOE observed for each product class during testing.

Table 5.3.2.2 Proposed Portable Dehumidifier Efficiency Levels for the Preliminary Analysis

Efficiency
Level Efficiency Level Source Integrated Energy Factor Efficiency Levels ( L /kWh )

20.00 pints/day

or less 20.01

– 30.00 pints/day 30.01

– 35.00 pints/day 35.01

– 45.00 pints/day 45.01 pints/day

or more

Baseline DOE Standard with Fan

only Mode 0.77 0.80 0.94 1.00 2.07

1 DOE Standard with no

Fan

- only Mode 1.10 1.10 1.20 1.30 2.40

2 Gap Fill 1* 1.20 1.20 1.40 1.40 2.80

3 Gap Fill 2 1.30 1.30 1.60 1.60 3.52

4 Maximum Available 1.42 1.52 1.75 1.75 N/A

* At the 65 ° F test condition, there was little correlation to performance at the 80 ° F test. Therefore, instead of using an efficiency level at the ENERGY STAR qualification criteria, DOE identified two gap fill levels between the equivalent DOE standards performance level and the maxi mum available.

5.3.2.2 Whole- Home Dehumidifier Product Class es

DOE analyzed several efficiency levels for whole-home dehumidifiers, and obtained
incremental cost data at each of these levels

. To determined efficiency levels for these ducted

5-8products, DOE investigated whole-home dehumidifiers according to the test setup proposed in
the XXX Test Procedure NOPR, which includes a ducted test configuration. CITE

. The additional ducting and static pressure drop across the unit generally reduce the efficiency and capacity when compared with the results from an unducted test setup. The efficiency levels that DOE selected for the preliminary analysis are based on the range of efficiencies observed during testing according to the XXX Test Procedure NOPR provisions. Table 5.3.2.3 includes the analyzed efficiency le vels based on the 80 ° F test condition and the reference source of each

level for the two whole- home pro duct classes.

Table 5.3.2.3 Whole- Home Dehumidifier Efficiency Levels at 80 ° F

Level Efficiency Level Source Integrated Energy Factor Efficiency Levels ( L

/kWh )

Less than or equal

to 8 .0 ft 3 (Case Volume) Greater than 8 .0 ft 3 (Case Volume)

B aseline Minimum Available 1.90 2.50

1 Gap Fill 1 2.20 2.80

2 Gap Fill 2 /Maximum
Available 2.50 3.50

3 Maximum Available N/A 4.20

As with the portable product classes, DOE also determined appropriate efficiency levels

at the 65 ° F test condition. Table 5.3.2.4 includes the reduced efficiency levels at 65 °F based on testing , which DOE used for the preliminary analysis.

5-9Table 5.3.2.4 Proposed Whole- Hom e Dehumidifier Efficiency Levels for the Preliminary Analysis

Efficiency
Level Efficiency Level Source Integrated Energy Factor Efficiency Levels ( L

/kWh)

Less than or equal

to 8 .0 ft 3 (Case Volume) Greater than 8 .0 ft 3 (Case Volume)

B aseline Minimum Available 1.10 1.68

1 Gap Fill 1 1.40 1.90

2 Gap Fill 2 /Maximum
Available 1.59 2.80

3 Maximum Available N/A 3.41

5.4 METHODOLOGY OVERVIEW

As discussed in Section 5.1, DOE typically follows one of three methodologies to perform the engineering analysis. In this case, DOE followed a hybrid approach that combined all three methodologies. DOE primarily followed the reverse engineering or cost- assessment approach with occasional input from the other two approaches, efficiency- level and designoption , where nece ssary. The reverse engineering approach established detailed manufacturer cost estimates for units in the teardown sample. For units at different efficiency levels, DOE assumed the differences in manufacturing costs were associated with the changes in effi ciency, similar to the efficiency -level approach. However, the units in DOE’s sample did not cover the range of capacities and efficiency levels analyzed. To cover these gaps, DOE relied on the design- option approach by adding certain design features to the units torn down, and accounting for the associated changes in efficiency, capacity, and cost.

DOE relied on multiple sources of information for this engineering analysis. These
sources include a review of TSDs from previous rulemakings, manufacturer inte rviews, internal product testing, and product teardowns.

5.4.1 Review of Previous Technical Support Documents and Models

DOE reviewed previous rulemaking TSDs to assess their applicability to the current standard setting process for residential dehumidifiers. These previous rulemaking TSDs served as a source for design options and energy consumption analysis, in addition to other sources. For dehumidifiers, the previous rulemaking TSD was developed in support of an advance notice of proposed rulemaking (ANOPR) published in 2007. 72 FR 64432 (Nov. 15, 2007).

5-105.4.2 Manufacturer Interviews

DOE understands that there is variability among manufacturers in baseline units, design strategies , and cost structures. To better understand and explain these variances, DOE conducted
manufacturer interviews . These confidential interviews provided a deeper understanding of the various combinations of technologies used to increase residential dehumidifier efficiency, and their associated manufacturing costs

. Sample questions for the engi neering analysis that were initially submitted to AHAM in advance of DOE’s interviews are contained in appendix 5A of this preliminary TSD. This questionnaire was subsequently updated to reflect the introduction of dehumidifier models meeting the October 2012 energy conservation standards, and was included as part of the interviews conducted in support of the preliminary analysis. Sample questions from the preliminary analysis interviews are contained in appendix 12A of this preliminary TSD

.

During the interviews, DOE also gathered information about the capital expenditures required to increase the efficiency of the baseline units to various efficiency levels ( i.e.

, conversion capital expenditures by efficiency or energy- use level)

. The interviews provid ed information about the size and the nature of the capital investments. DOE also requested information about the depreciation method used to expense the conversion capital. The preliminary manufacturer impact analysis in c hapter 12 of the preliminary TSD includes a
discussion of this information obtained during manufacturer interviews.

5.4.3 Product Testing

Much of the analysis in this chapter incorporates data from publicly available sources such as the CEC, DOE CCMS, and ENERGY STAR databases. However, DOE als o conducted
its own investigative testing according to the current and proposed DOE test procedure s for the following purposes:

• Verify performance trends that are apparent in the publicly available data;

• Develop a better understanding of the design options and product features currently available on the market;

• Investigate ducted performance for whole-home dehumidifiers; and

• Develop a better understanding of the operational characteristics of residential
dehumidifiers.

5.4.4 Product Teardowns

Other than obtainin g detailed manufacturing costs directly from a manufacturer, the most accurate method for determining the production cost of a product is to disassemble representative
units piece -by- piece and estimate the material , labor, and overhead cost s associated with each component using a process commonly called a physical teardown. A supplementary method, called a catalog teardown, uses published manufacturer catalogs and supplementary component data to estimate the major physical differences between a product that has been physically

5-11disassembled and another similar product. DOE performed physical teardown analysis on dehumidifiers in all product classes . The teardown methodology is exp lained in the following
sections

.

5.4.4.1 Selection of Units

DOE generally adopts the following criteria for selecting units for teardown analysis:

• T he selected products should span the full range of efficiency levels for each product class under consideration;

• W ithin each product class, the selected products should

, if possible, come from the same manufacturer and belong to the same product platform ;

• T he selected products should , if possible, come from manufacturer s with large market share s in that product class, although the highest efficiency products are chosen irrespective of manufacturer; and

• T he 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.

5.4.4.2 Generation of Bill of Materials

The end result of each teardown is a structured BOM, which describe s each product part and its relationship to the other parts, in the estimated order of assembly

. The BOMs describe each fabrication and assembly operation in detail, including the type of value—added equipment needed ( e.g. , stamping presses, injection molding machines, spot- welders, etc.) and the estimated cycle times associated with each conversion step . The result is a thorough and explicit model of the production process.

Materials in the BOM are divided between raw materials that require conversion steps to be made ready for assembly, while purchased parts are typically delivered ready for installation. The classification into raw materials or purchased parts is based on DOE’s previous industry experience, r ecent information in trade publications, and discussions with original equipment manufacturers (OEMs). For purchased parts, the purchase price is based on volume

- variable price quotations and detailed discussions with suppliers.

For parts fabricated in -house, the prices of the underlying “raw” metals ( e.g. , tube, sheet metal) are estimated on the basis of 5

- year averages to smooth out spikes in demand . Other “raw” materials such as plastic resins, insulation materials, etc. are estimated on a current

- marke t basis. The costs of raw materials are based on manufacturer interviews, quotes from suppliers, secondary research, and by subscriptions to publications including the American Metals Market c (AMM) . Past price quotes are indexed using applicable Bureau of Labor Statistics producer price index tables as well as AMM monthly data

.

c For information on American Metals Market, please visit: www.amm.com

.

5-125.4.4.3 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 5.4.4.1 shows the three major steps in generating the manufacturing cost.

Figure 5.4.4.1 Manufacturing Cost Assessment Stages

The first step in the manufacturing cost assessment 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 weight, 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 manufacturers. Interviews and plant visits were conducted with manufacturers to ensure accuracy on methodology and pricing.

Following the development of a detailed BOM, the major manufacturing processes were identified and developed for the spreadsheet model. Some of t hese processes are listed in Table
5.4.4.1

.

Table 5.4.4.1 Major Manufacturing Processes

Fabrication Finishing Assembly/Joining Quality Control Fixturing Stamping/Pressing Brake Forming Cutting and Shearing Insulating
Turret Punch Tube Forming Enameling Washing Powder Coating

De

- burring Polishing Refrigerant Charging Adhesive Bonding Spot Welding Seam Welding Packaging Inspecting & Testing

Fabrication process cycle times for each part made in

- house were estimated and entered
into the BOM. Based on estimated assembly and fabrication time requirements, the labor content of each appliance could be estimated. For this analysi s, DOE estimated labor costs based on typical annual wages and benefits of industry employees.

5-13Cycle requirements for fabrication steps were similarly aggregated by fabrication machine type while accounting for dedicated vs. non-dedicated machinery and/or change-over times (die swaps in a press, for exampl e). Once the cost estimate for each teardown unit was finalized, a detailed summary was prepared for relevant components, subas semblies and processes. The BOM thus details all aspects of unit costs : material, labor, and overhead.

Design options used in un its subject to teardown are noted in the summary sheet of each
cost model and are cost -estimated individually. Thus, various implementations of design options can be accommodated, ranging from assemblies that are entirely purchased to units that are made

e ntirely from raw materials. Hybrid assemblies, consisting of purchased parts and parts made on
site are thus also accommodated.

5.4.4.4 Cost Model and Definitions

The cost model is based on production activities and divides factory costs into the following catego ries:

• Materials: Purchased parts ( i.e. , motors, valves, etc .), raw materials, ( i.e. , cold rolled steel, copper tube, etc .), and 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: Materia l used during manufacturing ( e.g. , welding rods, adhesives).

• Fabrication labor: Labor associated with in

- house piece manufacturing.

• Assembly labor: Labor associated with final assembly.

• Supervisory labor: Labor associated with fabrication and assembly basis. Assigned on a span basis (x number of employees per supervisor) that depends on the industry.

• Indirect labor: Labor costs that scale with fabrication and assembly labor. These included the cost of technicians, manufacturing engineering support, stocking, etc . that are proportional to all other labor.

• Equipment depreciation: Money allocated to pay for initial equipment installation and replacement as the production equipment is amortized. All depreciation is assigned in a
linear fashion and affected equipment life depends on the type of equipment.

5-14• 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 a s a function of unit cost.

• Property Tax: Appropriated as a function of unit cost.

5.4.4.5 Cost Model Assumptions

As discussed in the previous section, assumptions about manufacturer practices and cost structure played an important role in estimating the final pro duct 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.
Site visits allowed DOE to confi rm its cost model assumptions through direct observation of the manufacturing plant, as well as through manufacturer interviews, reviews of current Bureau of Labor Statistics data, etc.

5.5 ANALYSIS AND RESULTS

5.5.1 Manufacturer Interviews

DOE conducted interviews with residential d ehumidifier manufacturers to develop a better understanding of current product features and the technologies used to improve energy efficiency. The manufacturers interviewed represent a wide range of U .S. market share and
included both do mestic and international companies that sell residential portable and wholehome dehumidifiers in the United States . During these interviews, DOE asked manufacturers questions about the following topics related to the engineering analysis :

• Product classes

• Design features of current baseline products

• Proposed incremental efficiency levels

• Design options required to meet each efficiency level

• Performance at reduced ambient temperatures

• Impacts on consumer utility

• Installation and repair costs as a function of efficiency

The discussion helped DOE understand what proposed design options have already been implemented and what additional design options DOE should consider.

The discussion below represents a consolidation of the manufacturer responses.

5-155.5.1.1 Product Clas ses

DOE asked manufacturers if the current product class divisions are appropriate. Manufacturers suggested various alternate product classes, none of which were consistent with the current product classes. The general response was that the current product classes are too granular, leading manufacturers to produce various models with different capacities yet identical efficiency ratings. Additionally, products with capacities near the end of the range of a product class are req uired to meet different minim um efficiency levels than similar units with slightly different capacities that would be classified in the adjacent product class. These products typically feature similar constructions and design features despite falling into separate product classes, so the units required to meet the higher minimum efficiency level may be penalized. Manufacturers indicated that product classes should not only reflect overall performance but also include design option restrictions for case volume and installation location.

5.5.1.2 Design F eatures of C urrent B aseline P roducts

DOE discussed with manufacturers the features of baseline products identified during the

reverse

- engineering analysis. The manufacturers generally agreed with DOE’s assumptions for a baseline unit, discussed in section 5.5.3.1 although not all manufacturers produce products at the baseline efficiency level. Manufacturers indicated that baseline dehumidifiers typically include the same components as units at higher efficiencies, perhaps with smaller heat exchangers or less efficient compressors.

5.5.1.3 Proposed Incremental Efficiency Levels

DOE asked manufacturers to comment on the proposed efficiency levels for the portable
and whole- home product classes. Manufacturers were asked to comment on the appropriateness of each incremental efficiency level, including the gap

- fill levels and the max

- tech levels. In general, manufacturers did not object to the efficiency leve ls DOE selected for analysis ; however, there was some concern that certain larger increments in efficiency between levels could be difficult to achieve. Also, some manufacturers were concerned about meeting the
maximum IEF levels with current materials and components. They suggest ed that higher efficiency products are currently being investigated, but the necessary changes are not completely understood at this time.

5.5.1.4 Design O ptions R equired to Meet E ach E fficiency L evel

DOE asked manufacturers to describe the changes associated with each active mode efficiency level relative to the baseli ne units in each product class. From the reverse-engineering analysis, DOE predicted the key design options would be increased compressor efficiency and heat exchanger sizes . DOE highlighted these options during discussions with manufacturers to determine the necessary design options to meet incrementally increased IEF levels

.

5-16Manufacturers generally agreed with DOE’s initial association of design options with the efficiency levels. They confirmed that the prim ary changes required to meet higher efficiency
levels will likely be more efficient compressors and optimized heat exchangers. Manufacturers stressed that making these changes would, for certain existing products, require a shift to larger
cases and therefore would increase the manufacturing costs and also require investments to update the manufacturing facilities

. These added costs would be passed down to the consumer, which could impact low- income consumers.

5.5.1.5 Performance at Reduced Ambient Temperatures

DOE asked manufacturers if the current 80 °F ambient dry- bulb temperature requ i red in Appendix X is appropriate for dehumidifier testing . M anufacturers generally agreed that the
current test conditions specify a higher dry- bulb temperature than those typically seen in the field; however, they did not provide additional consumer usage data to indicate a more appropriate test condition. Based on experience, manufacturers indicated that a n ambient temperature in the ran ge of 65 °F to 70 °F may be more appropriate than the current test condition. In addition to suggest ing that the test procedure should be conducted at a lower
ambient temperature

, manufacturers further indicated that they test their units at even lower
amb ient temperatures to ensure they will operate acceptably in low- temperature consumer installations

.

5.5.1.6 Impact on Consumer Utility

DOE asked manufacturers how these design option changes may impact consumer utility. Manufacturers indicated that overall performance would not be impacted; however, larger fans

may increase the fan operating noise, and larger components and cases would in crease the overall unit weight.

5.5.1.7 Installation and Repair Costs as a Function of Efficiency

Manufacturers generally indicated that typical product lifetime was the same for all dehumidifiers regardless of efficiency and component size. They also stated that repair and maintenance costs would not significantly change with improvements in efficiency.

5.5.2 Product Testing

DOE conducted extensive testing on dehumidifiers in each product class , including refrigerant

- based and refrigerant

- desiccant whole-home dehumidifi ers. These unit s were tested under varying conditions and test setups to investigate impacts on performance when compared to the current test procedure. DOE used the data obtained during testing to identify appropriate test conditions and setups as discuss ed in the XXX Test Procedure NOPR. For this engineering analysis, DOE used the data to determine appropriate product classes, efficiency levels, and the design changes necessary to achieve those levels

.

5-175.5.2.1 Product Selection

DOE tes ted a total of 2 4 portable units with rated capacities up to 75 pints/day, 13 large

capacity ( i.e. portable dehumidifiers with rated capacities greater than 75 pints/day) and refrigerant

- based whole-home units, and 2 refrigerant- desiccant whole- home dehumidifiers. The
test units spanned the range of capacities and efficiencies available on the market from multiple
manufacturers . The testing consisted of a series of investigations using various subsets of units in the test sample . However, all units were at minimum tested according to the existing test procedure in Appendix X. The test results inform ed both the proposals presented in the XXX
Test Procedure NOPR and this preliminary engineering analys is

.

5.5.2.2 Test Approach and Results

During testing, DOE investigated changes to dehumidifier performance under various operating conditions. To fully understand the dehumidifier operation at these different conditions, DOE gathered additional data compared to that required in Appendix X. The tests separately monitored the power consumption of the compressor and fan over the course of the

tests . This component monitoring allowed DOE to easily observe modifications to the compressor or fan cycling in response to changes in test setup and/or test conditions. For the majority of testing, DOE also m onitored the evaporator temperature to identify the points in operation at which condensate on the evaporator would freeze , which could impact dehumidification performance or require a defrost event

.

In response to comments received regarding the inapplicability of the 80 ° F test condition, DOE tested 20 of the 24 portable units with less than 75 pints/day rated capacity at
reduced ambient temperatures . Figure 5.5.2.1 and Figure 5.5.2.2 present the test results for portable dehumidifiers at the 80 °F and 65 ° F test conditions. The figures present the efficiency results in terms of EF to show the impact of the reduced temperature on active mode operation. DOE does not expect any effect on inactive mode, off mode, or fan- only mode performance due to the proposed lower ambient temperature

.

5-18Figure 5.5.2.1 Measured EF at 80 ° F and 65 ° F for Portable Dehumidifiers with Capacities Up to 75 pints/day at 80 ° F

Figure 5.5.2.2 Measured EF at 80 ° F and 65 ° F for Portable Dehumidifiers with Capacities Greater than 75 pints/day at 80 ° F

As discussed above in Section 5.3, and shown in Figure 5.5.2.1 and Figure 5.5.2.2

, DOE observed a decrease in both capacity and efficiency at the 65 ° F test conditio n when compared to
the 80 ° F test condition. DOE conducted additional testing at 55 °F; however, the majority of 0.75 0.95 1.15 1.35 1.55 1.75 1.95 2.15

0 20 40 60 80EF (L/kWh)

Product Capacity (pints/day) 80 F

65 F

1.5

2 2.5

3 3.5

4 4.5

0 50 100 150 200EF (L/kWh)

Product Capacity (pints/day) 80 F

65 F

5-19units tested at this condition were unable to con tinuously operate the compressor, and initiated defrosts during the test period by operating the fan without the compressor to remove frost from the evaporator. DOE confirmed the change in cycling through compressor power monitoring and verified frosting by placing a thermocouple on an evaporator tube bend midway between the evaporator inlet and ou tlet. As discussed in the XXX Test Procedure NOPR, DOE expects that dehumidifiers typically operate in locations with ambient temperatures higher than 55 ° F. CITE

.

As also described in the XXX Test Procedure NOPR, DOE developed a proposed ducted

test setup for whole- home dehumidifiers

. CITE

. DOE’s investigative testing monitor ed air flow, dry-bulb and wet

- bulb temperature s , and pressure at multiple locations in the test ducting . Tests
were conducted at various external static pressures and temperatures to determine the associated impact s on capacity and efficiency. Figure 5.5.2.3 shows the test results for the whole- home

dehumidifiers tested at both 80 ° F and 65 ° F according to the ducted setup proposed in the XXX
Test Procedure NOPR. As observed with the portable units, both capacity and EF are reduced at lower ambient temperatures.

Figure 5.5.2.3 Measured EF at 80 ° F and 65 ° F for Whole- Home Dehumidifiers

As discussed in the following sections, DOE utilized test data when conducting teardowns and modeling to correlate efficiency gains with certain design features or components
included in the units in the test sample. In particular, the testing informed the appropriate capacity and efficiency effects of the design features at the lower ambient temperatures, since

t here is limited publicly available information regarding dehumidifier operation at these
temp eratures. 0.5 1 1.5

2 2.5

3 3.5

0 50 100 150 200 250EF (L/kWh)

Product Capacity (pints/day) 80 F

65 F

5-205.5.3 Product Teardown s

After conducting the investigative testing described in the previous section, DOE
conducted teardowns on 32 out of its 39 test units , including both portable and whole- home products. The test units spanned the range of product efficiencies and features available on the market from multiple manufacturers. DOE relied on the dehumidifier teardowns to supplement the information gained through manufacturer interviews and to investigate performance observed during testing. Specifically, the teardowns allowed DOE to identify design features for improving efficiency and to develop corresponding manufacturing costs for products at different efficiency levels.

5.5.3.1 Baseline Construction

DOE observed that the baseline portable dehumidifiers in the teardown sample for the product classes with capacities up to 75 .00 pints/day at 80 °F, equivalent to 45.00 pints/day at 65 °F, had similar constructions. All of the units were housed in a plastic case with a removable bucket. They featured rotary R-410A compressors at the base of the unit, with the evaporator and condenser housed in the top of the unit along with the fan and air filter. DOE observed that the blowers all used permanent split capacitor (PSC) motors. The evaporator and condenser within a
unit were similar in construction, with similar dimensions and number of tube passes, and they were connected via capillary tubes. The copper tubing exiting the evaporator and entering the

co mpressor was typically insulated, though the thickness and length of insulation varied among
units. All of the units in DOE’s sample for these lower

- capacity portable product classes featured electronic controls, although DOE is aware that certain units may still use electromechanical
controls.

For the high- capacity portable dehumidifier product class and both whole-home dehumidifier product classes, the baseline product shifted to a different design, but still contained most of the same general components. As expected for these product classes, the internal components related to the product capacity were noticeably larger than for the other portable product classes. In particular, t hese units used higher capacity compres sors, larger heat exchangers, and more powerful blowers. One key difference when compared to the other portable product classes is the elimination of the internal condensate collection bucket. All of the high- capacity units in DOE’s teardown sample were de signed to be connected to a drain. Also, the units in these product classes featured metal cases with more insulation than the plastic cases for the other portable dehumidifier product classes.

DOE observed that manufacturers that produce high- capacity p ortable units also typically produce whole-home dehumidifiers. For products from the same manufacturer in the same capacity range, DOE observed that the high- capacity portable and whole-home products contained almost identical internal components. The only major differences between these products were the ducting attachments for whole-home units (and lack of ducting attachments for portable units) and the differences in controls. Whole-home products are typically controlled via
a remote humidistat with no on-board user controls, while the portable products are controlled through the user interface on the unit. High

- capacity portable products typically used

5-21electromechanical controls , unlike lower- capacity portables units , most likely due to simplicity, high reliability , and minimal expected consumer interaction.

5.5.3.2 Design Options to Reach Higher Efficiency Levels

In chapter 3 of this preliminary TSD, DOE identified technology options that could potentially improve the efficiency of dehumidifiers. As discussed in chapter 4 of this preliminary TSD, certain of these technology options were eliminated from further consideration in the engineering analysis. DOE considered the technology options meeting all of the screening criteria in this engineering analysis, although not all of these design options factored into the final estimated incremental costs. This section explains how DOE addressed each of the technology options that were not screened out.

Retained Design Options to Meet Higher Efficiency Levels
Based on testing, manufacturer interviews, and product teardowns, DOE identified the following key design changes to reach higher efficiency levels: improved compressor efficiency, imp roved evaporator and condenser performance ( i.e.

, larger heat exchangers), and pre -cooling
air

- to

- air heat exchangers.

Improved compressor efficiency
Improved compressor efficiency is one of the primary ways dehumidifiers can achieve higher efficiencies . The compressor typically represents 80 to 90 percent of a dehumidifier’s energy consumption, so small improvements in compressor efficiency translate directly to
measurable improvements in IEF. DOE is aware that rotary R

- 410A compressors are available
wi th a range of efficiencies, and manufacturers will likely move to a more efficient compressor to achieve higher IEFs.

In chapter 3 of the preliminary TSD , DOE also identified inertia -reciprocating, scroll, and variable speed compressors to further increase efficiency beyond traditional rotary compressors.
DOE notes that inertia

- reciprocating and scroll compressors are substantially larger, heavier, and noisier than rotary compressors, and therefore are not suited for residential dehumidifiers.
Variable -speed compressors present an opportunity for a dehumidifier to adjust the compressor and refrigeration system operation to varying conditions. However, becau se the DOE test procedure is conducted at constant ambient conditions with continuous operation, it would not capture efficiency gains associated with variable

- speed compressors. Therefore, DOE did not
consider inertia

- reciprocating, scroll, or variable

- speed compressors in the remainder of its analysis.

Improved condenser and evaporator performance

DOE also observed that manufacturers may use larger heat exchangers at the higher efficiency levels. Compressor efficiencies can only improve a dehumidifier’s performance to a certain extent for a given refrigeration system. Larger heat exchangers can help to further improve the performance of the refrigeration system by more effectively converting the work performed by the compressor into heat transfer. As mor e heat is absorbed in the evaporator and

5-22r ejected via the condenser, the refrigerant cycle operates more efficiently and less compressor power is required to achieve a similar capacity.

As discussed in c hapter 3 of this preliminary TSD , many parameters affect a heat exchanger’s performance. Based on manufacturer interviews and product teardowns, DOE found
that manufacturers may adjust the cross

- sectional area of the heat exchangers to increase heat transfer. DOE observed that the condenser and evaporator in all of its teardown units had similar construction, but the cross- sectional area was the key parameter that changed from unit to unit. In its analysis, DOE assumed that manufacturers would rely on increased heat exchanger sizes to improve condenser and evaporator performance.

Pre -cooling air- to

- air heat exchanger

Pre

- cooling air

- to

- air heat exchangers further increase the efficiency of whole -home and high- capacity portable dehumidifiers. By cooling the inlet air stream using the low

- temperature air exi ting the evaporator, the air- to

- air heat exchanger decreases the amount of sensible heat the evaporator must remove from the air stream before condensation occurs. Because the heat exchanger uses evaporator outlet air to cool the inlet airstream, the air e ntering the condenser is a higher temperature. The result is a slightly higher temperature exhaust air off of the condenser, but overall improved dehumidifier energy efficiency.

DOE considered pre-cooling air- to -air heat exchangers as a design option for the wholehome and high- capacity portable dehumidifier product classes, but screened out this technology option for the smaller

- capacity portable dehumidifier product classes for the reasons described in chapter 4 of this preliminary TSD.

Design Options Not Used to Meet Higher Efficiency Levels
DOE observed that manufacturers typically implement the design options discussed above to improve dehumidifier efficiency. Additionally, while many of the technology options identified in chapter 3 of this prelimi nary TSD may produce energy savings in certain real-world situations, DOE did not further consider them in this analysis because the DOE test procedure would not capture those potential improvements . DOE considered the following design options in this engi neering analysis, but does not expect manufacturers to rely on these features to meet higher efficiency levels.

Built

- in h ygrometer/ h umidistat
All portable dehumidifiers in DOE’s teardown sample featured a built- in humidity controller. These units all included electronic controls, but DOE is aware that certain units may still feature electromechanical humidistats. The humidistat cycles the compressor and fan power supply as a function of relative humidity. Both electronic and electromechanical controllers measure the expansion of a reference material as a function of relative humidity. DOE notes that whole-home dehumidifiers are often designed to be used in conjunction with a remote humidistat. The humidistat is placed in the portion of the home that requires dehumidification, and cycles the whole-home dehumidifier compressor and fan power supply as needed. Although

5-23this control is external to the unit, DOE does not expect significant differences in efficiency or operation when compared to the built-in controls on portable units.

While electronic humidistats may provide more flexible control in cycling the refrigeration system as -needed in varying conditions, DOE does not expect the type or presence of a hygrometer or humidistat to affect dehumidifier effi ciency. The DOE test procedure requires continuous unit operation at constant ambient conditions, and therefore does not reflect performance of the humidity sensor. Because DOE does not expect the type of humidity controller to result in efficiency gains, and because the test procedure would not capture any efficiency improvements, DOE did not further consider changes to the hygrometer or humidistat in this preliminary analysis.

Improved controls

Similar to the built -in hygrometer/humidistat discussed above, improved controls may
allow dehumidifiers to better adjust their operation in response to changing conditions. Improved controllers may consider multiple inputs, such as ambient temperature, ambient humidity, and evaporator temperature, when adjusting unit operation. Because the DOE test procedure requires continuous unit operation at constant ambient conditions, it therefore would not reflect improved
control schemes and DOE did not further consider improved controls in this preliminary analysis.

Improved defrost methods

In chapter 3 of this preliminary TSD , DOE identified four defrost types: passive, fanonly, electric, and hot- gas. DOE is not aware of any units on the market that feature an electric or hot-gas defrost, although there are no tec hnical limitations that would preclude these in dehumidifiers. DOE also did not observe passive defrost in its testing. DOE observed that units typically use a fan-only defrost when necessary.

The current DOE test procedure does not test at ambient conditions where defrost cycles

are likely to occur. However, DOE did observe that some units in the test sample entered fan

only mode when tested at the 65 °F ambient temperature proposed in the XXX Test Procedure NOPR. While improved defrost methods could improve energy consumption in these units when tested at 65 °F ambient temperature, DOE expects that manufacturers would likely adjust the unit
controls or refrigeration system operation to avoid triggering a defrost at these reduced ambient
temperatures rat her than improving the defrost. DOE did not observe different design features between the units that did or did not defrost at the reduced ambient temperature, so the difference in operation is likely due to different control schemes or refrigeration syste m operating parameters. Because manufacturers would likely adjust their units to avoid defrosts when operating at 65 °F ambient temperature, DOE did not further consider different defrost methods in determining how manufacturers may achieve higher efficien cy levels.

Improved demand

- defrost controls
Defrost controls determine when a defrost cycle is needed, and the duration of the defrost cycle. As described in chapter 3 of this preliminary TSD, time

- based defrosts occur at regular

5-24intervals for constant d uration as a unit operates. Sensor-controlled defrosts occur as needed based on evaporator coil temperatures. DOE observed that all units in the teardown sample featured temperature sensors on the evaporator coil, and therefore likely employ a sensor

controlled defrost. DOE also observed that units did not enter a defrost cycle when tested at 80 °F ambient temperature, some units defrosted at 65 °F, and nearly all units defrosted at 55 °F. This also suggests a sensor -based defrost.

Because DOE expects that units available on the market already feature sensor -based defrost control, and because DOE expects that the test procedure likely would not capture defrost cycles as described in the section above , DOE did further consider this feature in this prelim inary analysis.

Improved fan and fan

- motor efficiency
DOE is aware that efficiency gains may be possible through improve ments to the fan and
fan -motor. DOE noted that all units in its teardown sample used permanent split capacitor (PSC)
PSC fan motors, which have improved efficiencies compared to shaded-pole motors. However,

p ermanent -magnet motors would provide slightly higher motor efficiencies compared to PSC motors, but the overall improvements to IEF would be small due to the relatively smal l portion of energy consumed by the fan motor compared to the compressor. Manufacturers would also incur significant costs with employing permanent- magnet motors; the motors themselves cost over two times as much as a comparable PSC motor, and the different shape and weight of the motor may require product redesign.

Manufacturer interviews and product teardowns also showed that there were no significant changes to the blowers and fan motors at different product efficiencies. For these reasons, DOE did not further consider improved fan and fan-motor efficiency in developing the

cost

- efficiency relationships. DOE notes that because it conducted a hybrid analysis, including the efficiency -level approach, changes in the fan and fan- motor between units in the teardown sample are reflected in DOE’s cost estimates. Improved fan and fan

- motor efficiency was not considered as a design option for the portion of the analysis that relied on the design-option approach.

Improved flow- control devices

DOE observed that all units in the teardown sample used a wound capillary tube as the expansion device to control refrigerant flow to the evaporator, though the length and size of tubing varied. In c hapter 3 of this preliminary TSD , DOE described how thermostatic expansion valves or electronic expansion valves would allow dehumidifiers to regulate refrigerant flow to the evaporator based on changes in operating conditions.

As discussed for previous design options, the DOE test procedure is performed under

constant ambient conditions, and any benefit associated with a unit’s ability to adjust to varying
ambient conditions would not captured in the test. Therefore, DOE did not further consider improved flow- control devices as a design option.

Low

- standby

- loss electronic contr ols

5-25In its test and teardown sample, DOE observed that the presence of a fan -only mode had the most significant impact on the conversion from EF to IEF based on the calculations to incorporate low -power mode energy consumption as proposed in the XXX Test Procedure
NOPR. CITE . For units without a fan-only mode, DOE observed that low-power mode energy consumption resulted in an average decrease from EF to IEF of 0.02 L/kWh. For all units in the test sample, the average inactive mode or off mode power consum ption was 0.9 Watts (W)

.

DOE observed two types of power supplies in its teardown sample: linear and switchmode. Switch-mode power supplies typically require lower standby power compared to linear power supplies. In the test sample, DOE found an average off-mode power of 0.37 W for switchmode power supplies compared to 1.2 W for linear power supplies. In off-cycle mode, for units without fan-only mode, units with switch-mode power supplies required on average 1.14 W compared to 1.63 W for units with linear power supplies. DOE notes that based on these average power inputs, the effect of changing from a linear to a switch-mode power supply has very little impact on IEF. For example, the IEF of a baseline 50 pint/day unit with an EF of 1.6, at 80 °F ambient temperature, would be rounded to 1.59 with either a linear or switch-mode power supply.

DOE also observed a range of power inputs for each power supply type. While switchmode power supplies required less power on average than linear power supplies, DOE observed linear power supplies with off-mode and off-cycle mode power inputs as low as 0.51 W and 0.72 W, respectively.

Because of the relatively small impact of standby mode and off mode energy consumption on IEF, and the range of power inputs associated with each power supply, DOE did not consider this a specific design option in its analysis. However, because DOE relied on a hybrid analysis approach, including the efficiency- level approach, DOE’s cost estimates reflect both power sup ply types based on the units torn down at each efficiency level and product class. DOE did not use low-standby controls as a design option in the design -option approach portion of the analysis because of the relatively large jumps in efficiency between the analyzed IEF
levels

. DOE tentatively concludes that manufacturers would rely on other changes , such as improved compressor efficiency and heat exchanger effectiveness

, to achieve the higher
efficiencies.

Washable air filters
DOE found that all portable dehumidifiers in its test and teardown sample include a washable air filter. The manufacturer instructions suggest that the consumer periodically clean the filter to minimize particulate build up and ensure optimal performance. However, because all units use a washable air filter, DOE did not consider this as a design option to improve efficiency.

Heat p ipes

As discussed in chapter 4 of this preliminary TSD, DOE screened out heat pipes as design option for portable dehumidifiers with up to 75 pints/day capacity at 80 ° F . The size and

5-26weight of added heat pipes would have less of an impact on consumer utility for portable units with more than 75 pints/day capacity at 80 ° F and for whole-home dehumidifiers.

DOE was unable to find any residential dehumidifiers that use heat pipes to boost performance by pre- cooling the inlet evaporator air. DOE is aware that units existed on the market until 2010, at which point the manufacturer chose to discontinue the product line for reasons unknown to DOE. Although heat pipes have been incorporated in the past, DOE does not expect manufacturers to use this design option to achieve higher efficiencies because p re -cooling
air

- to

- air heat exchangers accomplish the same function of pre

- cooling the air entering the evaporator, likely with similar efficiency improvements. However, pre-cooling air- to

- air heat exchangers lower the temperature of the incoming air using a simpler design. They do not require a heat transfer liquid, and can be made of less costly materials. Accordin gly, the air- to

- air heat exchangers are likely lower cost than equivalent heat pipes that accomplish the same function. Therefore, DOE did not further consider heat pipes in its analysis because it tentatively
concludes that manufacturers of whole-home and higher- capacity portable dehumidifiers would likely use pre-cooling air- to

- air heat exchangers in their place

.

Improved refrigeration system insulation
Through teardowns, DOE observed that manufacturers typically include insulation on the refrigeration system. The most commonly insulated part of the system is the evaporator outlet and compressor inlet. However, DOE did not observe that the products at hig her efficiency levels include different insulation types or quantities. Further, manufacturers did not indicate that higher efficiencies could be achieved with more insulation , although some m anufacturers commented that insulating the product’s case typically helps the unit’s noise performance. Because DOE did not observe a relationship between product efficiency and refrigeration system insulation, it did not consider this as a design option when developing cost- efficiency curves. However, because DOE used a hybrid approach for this analysis, the estimated costs for each product torn down reflect the type and quantity of insulation included in those products.

Refrigerant

- desiccant systems
DOE is aware that refrigerant

- desiccant systems may offer improved performance, particularly in low

- temperature installations where defrosting may be a concern for refrigerant

only dehumidifiers. DOE investigated the potential improvements in efficiency and capacity from incorporating a desiccant wheel in a whole-home dehumidifier. Based on testing, DOE did not observe any efficiency or capacity improvement with incorporating a desiccant wheel. However, DOE notes that testing is conducted at ambient temperatures where defrosting is likely

not a concern, so it may not reflect the improvements associated with a refrigerant

- desiccant system at low temperatures. Because DOE did not observe higher efficiencies for refrigerant

desiccant units under representative ambient conditions , it did not further consider these units in this preliminary analysis.

5-275.5.4 Numerical Model

Although DOE tested and tore down a large sample of units from different manufacturers at varying capacities and efficiencies, the sample did not cover the entire range capacities and efficiency levels that DOE is proposing to analyze for potential standards. To fill in gaps in the teardown sample, DOE used a numerical model to estimate unit performance at different efficiency levels and capacities.

5.5.4.1 Su mmary

To conduct the energy modeling, DOE used the MarkN program developed for use in the most recent room air conditioners direct final rule. 76 FR 22454 (Apr. 21, 2011). The MarkN program was itself an update of an adaptation to the Oak Ridge National L aboratory Mark III Heat Pump program for modeling room air conditioner cooling performance. This program was originally used in support of the 1997 room air conditioners final rule. 62 FR 50122 (Sept. 24, 1997). The 1997 final rule and 2011 TSD d provide fu rther details regarding the use of these programs in support of the room air conditioners energy conservation standards rulemakings.

DOE modified the room air conditioner numerical model for this dehumidifier analysis
because both product types use simi lar technologies —an evaporator to absorb heat from an air stream, a compressor, a condenser to eject heat to an air stream, and an expansion device between the two heat exchangers. The only major difference in the operation of the two product types is the airflow through the unit. Room air conditioners have two separate air streams through the unit, one for the indoor air to be cooled over the evaporator and the other for the external air that absorbs the heat rejected by the condenser. Dehumidifiers pass the same air stream over the evaporator and condenser, first cooling the air on the evaporator to condense water, then re -heating the air over the condenser before exhausting the drier air back to the room
or return air stream.

To account for this difference in operation, DOE adjusted the MarkN model to set the
condenser inlet air conditions (typically the outdoor air conditions for room air conditioners) equal to the evaporator outlet air conditions (typically the indoor return air conditions for room
air conditioners ). Through an iterative process, the revised program adjusts the condenser inputs for the MarkN program until they are within a tolerance of the evaporator outlet conditions, effectively modeling one air stream throu gh both heat exchangers.

5.5.4.2 Analysis Method

DOE first used the numerical model to simulate unit performance for the models in the test and teardown sample. The model inputs include product component specifications and the ambient operating conditions. DOE obtained component information from the product

d The TSD in support of the 2011 room air conditioners final rule can be found at: http://www.regulations.gov/#!documentDetail;D=EERE

- 2007 -BT- STD

- 0010

- 0053

5-28teardowns, including heat exchanger construction (number of rows, tube passes, tube spacing, fin spacing, etc.), refrigerant tubing (lengths and diameters of inlet/outlet tubes and capillary tubes), and compressor specifications.

The model requires detailed compressor operating information, including the mapping coefficients for refrigerant mass flow and power input at varying evaporator and condenser operating temperatures. DOE lacked this information for almost all units in the teardown and test sample. However, DOE used the data from testing to calibrate the model for each individual unit using a base case of compressor mapping inputs. After calibrating the model, DOE achieved close agreement between the mo del outputs and test data at both 80 °F and 65 °F ambient
conditions.

DOE then used the model to determine the design changes necessary to reach different efficiency levels or capacity ranges not covered by the models in the teardown sample. For most

por table dehumidifiers, DOE observed that manufacturers typically use two methods to increase product efficiency: (1) improving the compressor efficiency, and (2) increasing the heat exchanger cross

- sectional areas. Based on inputs from manufacturer interviews, DOE is aware that improving compressor efficiency is likely the first option to improve a unit’s efficiency before increasing the heat exchanger sizes. Increasing heat exchanger area could also require a change to a larger case size, which requires a hi gher material cost per unit

, significant conversion costs to update the manufacturing facilities , and can increase shipping costs if fewer units can be transported in shipping containers. So, DOE assumed that manufacturers would first maximize the compress or efficiency within a unit to achieve higher efficiencies.

To determine appropriate ranges of compressor efficiencies, DOE surveyed available ratings for rotary R-410A compressors over the range of typical compressor capacities observed
in dehumidifiers. As shown in Figure 5.5.4.1 , compressors are available within this capacity range at rated energy efficiency ratios ( EERs ) ranging from roughly 8.5 to 10.5 British t hermal units per hour per Watt (Btu/h/W ) . DOE notes that this range represents a limited number of

compressors based on a survey of the market, not necessarily those observed during teardowns. DOE lacked rated information on the compressors found during teardowns, but expects the range presented in Figure 5.5.4.1 to be representative of compressors available to dehumidifier
manufacturers.

5-29Figure 5.5.4.1 R- 410A Compressor Performance Characteristics

When increasing compressor EER to 10.5 Btu/h/W did not result in a sufficient increase
in IEF to reach a certain efficiency level, DOE then increased the condenser and evaporator

cross

- sectional areas in the model inputs. Manufacturers generally informed DOE that increasing the heat exchanger cross- sectional areas had the most significant impa ct on dehumidifier efficiency when compared to other heat exchanger changes, such as increasing the number of tube rows or return bends in a heat exchanger of the same cross- sectional area. DOE investigated these other changes using the model, and the resu lts were consistent with the manufacturer
information.

Improved compressor efficiencies and increased heat exchanger areas allowed DOE to analyze the design changes needed to meet each efficiency level for the lower -capacity portable
and smaller -volume whole -home dehumidifier product classes. At higher efficiency levels, the highest- capacity portable and large -volume whole-home dehumidifier product classes incorporate inlet air

- to -air heat exchangers. The numerical model did not incorporate a feature to
simulate an inlet air

- to -air heat exchanger, so DOE relied only on unit teardowns for the analysis at these higher efficiency levels.

5.5.5 Cost Estimates

For the models in the teardown sample, DOE developed manufacturer cost estimates based on the method outlined in section 5.4.4. As discussed above, DOE did not tear down units from each manufacturer at each capacity and efficiency level. In these cases, DOE relied on the numerical model to determine the design changes needed for a model in the teardown sample to reach a given efficiency or capacity level. DOE estimated that if a switch to a more efficient 7.5

8 8.5

9 9.5 10 10.5

11

0 5000 10000 15000 20000Rated Compressor EER (Btu/h/W)

Rated Compressor Capacity (Btu/h)

5-30compressor was the only necessary design change, there would be no additional changes to the rest of the product. However, for units requiring larger heat exchangers, DOE scaled the size of
the case and other related components to accommodate the larger coils.

In developing its cost estimates, DOE lacked detailed compressor pricing information. The compressor is often the most co stly component in a dehumidifier, typically representing 20 to 30 percent of the product’s material cost. DOE requested compressor pricing information during manufacturer interviews, but did not receive enough detailed feedback to develop cost
estimates fo r all of the compressors found during teardowns or specified through the numerical
model.

DOE did , however, receive compressor pricing information from manufacturers during the 2011 energy conservation standards rulemaking for room air conditioners. Dehu midifiers and
certain room air conditioners both use similar rotary compressors for R -410A refrigerant. Figure
5.5.5.1 presents the compressor cost in formation gathered during the room air conditioner rulemaking, and presented in chapter 5 of th at direct final rule TSD.

Figure 5.5.5.1 R- 410A Compressor Cost from Room Air Conditioner Direct Final Rule Analysis

DOE observed in this rulemaking that certain dehumidifiers use compressors with capacities less than 5,000 Btu/h, which are not represented by the curve. If the curve in Figure
5.5.5.1 were extrapolated to lower than 5,000 Btu/h, the resulting costs would not appear to be representative . For example, a 3,000 Btu/h compressor (roughly the lowest observed in the teardown sample) would be estimated to cost less than $7; a 2,500 Btu/h compressor would have a negative estimated cost. To model these low er compressor capacities , therefore, DOE 0 20 40 60 80 100 120

0 5000 10000 15000 20000 25000 30000Compressor Cost ($)

Capacity (Btu/h)

5-31extrapolated the curve using a linear relationship between $0 and 0 Btu/h capacity and the endpoint of the curve at 5,000 Btu/h capacity.

5.5.5.1 Baseline Cost Estimates

From product teardowns and the numerical model, DOE developed the following
baseline manufacturer product costs for each of the dehumidifier product classes . All costs presented are in 2012 dollars.

Table 5.5.5.1 Baseline Dehumidifier Manufacturing Cost Distribution

Portable Product Class Capacities (pints/day at 80 °F and 65° F) Whole

- H ome Product
Class Case Volume (ft

3 )

Cost Category ≤ 35 35.01

- 45 45.01

- 54 54.01

- 75 > 75 ≤ 8.0 > 8 .0 ≤ 20 20.01

- 30 30.01

- 35 35.01

- 45 > 45

Raw Materials $24.49 $24.10 $28.08 $33.46 $75.29 $54.59 $109.46

Purchased Parts $66.47 $72.88 $79.91 $84.50 $194.72 $192.84 $239.96

Ass embl y Labor Cost $1.61 $1.58 $1.66 $1.78 $24.60 $20.95 $32.38

Fab Labor Cost $1.05 $1.04 $1.28 $1.28 $35.52 $33.58 $40.37

Supervision Cost $0.14 $0.14 $0.15 $0.16 $3.13 $2.84 $3.78

Indirect Labor Cost $0.92 $0.91 $1.02 $1.06 $20.87 $18.93 $25.26

Equipment Dep. Cost $3.83 $3.83 $4.92 $4.91 $37.75 $34.20 $41.09

Tooling Dep. Cost $3.85 $3.81 $4.99 $4.85 $11.73 $11.40 $10.99

Building Dep. Cost $1.59 $1.59 $1.98 $2.12 $14.68 $14.11 $13.52

Indirect Process Costs $2.27 $2.27 $2.35 $2.34 $6.39 $5.71 $10.77

Total $106.22 $112.14 $126.36 $136.47 $424.67 $389.13 $527.59

5.5.5.2 Incremental Cost Estimates

As discussed in the previous sections, DOE either tore down or developed simulations for models at each efficiency level for the different product classes. DOE developed manufacturing cost estimates for each product, and determined the incremental manufact uring cost needed to meet each efficiency level when compared to the baseline for a given product class. Table 5.5.5.3 presents these incremental manufacturing costs.

Table 5.5.5.2 Incremental Dehumidifier Manufacturing Costs at Higher Efficiencies Portable Product Class Capacities (pints/day at 80 °F and 65° F) Whole

- H ome Product
Class Case Volume (ft 3 )

Efficiency Level ≤ 35 35.01

- 45 45.01

- 54 54.01

- 75 > 75 ≤ 8.0 > 8 .0 ≤ 20 20.01

- 30 30.01

- 35 35.01

- 45 > 45

5-32EL1 $- $- $- $- $38.40 $15.22 $6.14

EL2 $1.56 $1.85 $2.94 $1.98 $49.16 $76.18 $37.05

EL3 $4.64 $3.78 $8.72 $7.56 $100.13 $112.01

EL4 $7.77 $10.82 $13.40 $11.24

DOE notes that the portable dehumidifier product classes with capacit ies at or below 75 pints/day at 80 °F , equivalent to 45 pints/day at 65 °F, have zero incremental cost for reaching the first efficiency level. As discussed in section 5.3.1 , the baseline IEF’s for these product classes assume the presence of a fan -only mode. DOE did not observe any unique design features associated with the presence or absence of fan -only mode operation, and expects the only cost associated with eliminating fan -only mode to be the cost of reprogramming the unit controls.

Becau se this is only a design cost, DOE does not expect any additional production cost for eliminating fan -only mode. Accordingly, DOE estimated zero incremental cost to reach EL1 for these product classes.

5-33