5.7 ENERGY MODELING 

DOE carried out detailed energy modeling of representative baseline and 

ENERGY STAR refrigeration products as one indication of the incremental costs 

required to achieve higher efficiency levels. The products selected for reverse 

engineering provided the basis for the energy modeling. Energy model input was 

determined for these products from the data collected during the reverse engineering 

work, described in Section 5.5.3. Additional data used both as input and for calibration of 

individual product energy models was provided by energy testing as described in Section 

5.5.5. Energy modeling was also conducted for modified designs using groups of design 

options to improve efficiency to determine the expected energy savings associated with 

the design options. Using the energy modeling results and manufacturing cost modeling 

results for these designs allowed DOE to develop incremental cost estimates for multiple 

efficiency levels based on each of the baseline products analyzed. 

DOE carried out energy modeling during this rulemaking using an improved 

version of the EPA Refrigerator Analysis (ERA) program, earlier versions of which have 

been used in previous refrigerator rulemakings. Section 5.7.1 describes the ERA model 

development briefly. A more detailed description of the program and its recent 

development is presented in appendix 5-B. 

5.7.1 Energy Model development 

ERA is a steady-state energy model that calculates heat leakage into a cabinet and 

determines the energy needed by the refrigeration system to maintain the interior 

temperatures as specified by the user. Total energy used includes the energy from the 

compressor, fan motors, defrost heater, electronic control, and anti-sweat heaters, if 

applicable. See appendix 5-B for a detailed explanation of the ERA model. 

The DOS version of ERA was developed initially under EPA-sponsorship during the late 

1980s. This was undertaken by the EPA as part of its involvement in the establishment of 

energy standards for refrigerators, refrigerator-freezers, and freezers under the National 

Appliance Energy Conservation Act of 1987 (NAECA). A developmental version of the 

program was used by the DOE as a partial basis for the energy standard established in 

1989 (effective in 1993). The work also involved extensive testing of the model against 

manufacturer-supplied refrigeration appliance design and test data. Based on these 

comparisons and manufacturer review comments through its industry organization 

(AHAM), development of the model continued until its release in 1997.1 

ERA combined an analysis of the refrigeration load requirements of the cabinet with a 

simulation of the capacity and efficiency of the refrigeration cycle. The cabinet loads 

module was a modest enhancement of a program developed for the DOE during the late 

1970s,2 including the consideration of door-opening effects on the load and an ability to 

deal with complex insulation systems. The cycle module was a derivative of the NIST 

CYCLE 7 program,3

 which used the CSD equation of state to represent the 

thermodynamic properties of pure and mixed refrigerants,4

 adapting routines for 

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EERE-2008-BT-STD-0012 COMMENT 20
 

calculating refrigerant properties from REFPROP3.5 The program, and its User’s Manual, 

were first released to the public in 1993, and for a few years were downloadable from the 

EPA website.6 Subsequent to the 1993 final rule, DOE published updated standards for 

refrigerators, refrigerator-freezers and freezers in 1997, becoming effective in 2001. 

Analysis carried out in support of the 1997 final rule involved use of the final released 

EPA version of ERA.1 

The DOS version of ERA was subsequently modified as described in appendix 5-B, but 

these revisions were not made available to the public. During the course of this 

rulemaking, further development of the model was carried out in order to allow use of the 

model for calculation of energy use of modern residential refrigeration products and to 

allow a modern version of the program to be made available to stakeholders to validate 

DOE analysis. Key modifications made include the following. 

•	 Enhancement of the user-interface to a Windows environment 

•	 Employment of the most current refrigerant property routines 

•	 Incorporation of a broad range of evaporator and condenser algorithms that 

correspond to the technologies now found in modern refrigerators 

•	 Improved compressor modeling, with built-in procedures for validating supplied 

compressor maps 

•	 Improvements where desirable in the cabinet loads analysis and cycle performance 

algorithms. 

•	 Preparation of internal documentation of the program through extensive contextsensitive Help files. 

Many of the energy model calculations described in this chapter were made using a DOS 

version of the ERA program prior to the completion of the Windows version. 

The development history and capabilities of the program are described in more detail in 

appendix 5-B. 

5.7.2 Supplemental Spreadsheet Models 

Spreadsheet analysis tools were developed and used as part of some of the energy 

model development and calculations in order to (1) calculate airside heat transfer 

performance of spine fin evaporators, (2) determine appropriate composite insulated wall 

thermal resistivity when calculating cabinet thermal performance using vacuum panel 

insulation, and (3) adjusting ERA energy model output results for some product 

configurations for which ERA did not allow input of separate thermal resistivity for 

separate walls. 

Spine fin evaporator airside heat transfer performance was calculated using a 

spreadsheet. Equations for the model were based on the work of Holtzapple and 

Carranza.7,8 The ERA heat exchanger models (the ERAEVAP program) provided heat 

transfer coefficients for refrigerant-side heat transfer in the two-phase and superheated 

regimes. Using these values, the spreadsheet model provided the overall heat transfer 

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EERE-2008-BT-STD-0012 COMMENT 20
coefficients for the two regimes of the evaporator and the effective heat transfer area, 

which were the inputs for DOS version of ERA. 

When modeling use of vacuum insulation panels (VIPs), the cabinet walls or door 

have two regions of differing thermal resistivity. Average values of resistitivity were 

calculated and entered into ERA to model these composite insulation systems. 

The ERA model structure did not allow separate specification of insulated wall resistivity 

for the compressor compartment—the program uses the bottom surface resistivity for this 

region of the cabinet. In some cases, separate spreadsheet calculations were conducted to 

adjust energy model results to account for the different resistivity that may be used in this 

region. For this calculation, used when application of VIP to the bottom surface was 

considered, the compressor compartment thermal load was increased proportional to the 

ratio in resistivities of the modeled surface and the composite surface including VIP. The 

compressor energy use was then increased in proportion to the reduction in overall 

thermal load. 

5.7.3 Development and Calibration of ERA Current Energy Test Models 

ERA modeling during the engineering analysis involved the following three 

phases. 

•	 Modeling of existing products based on the current energy test procedure. 

•	 Adjustment of models to represent baseline products tested under the expected 

revised test procedure. 

•	 Iterative modeling with multiple series of adjustments to calculate the energy savings 

which can be achieved with different combinations of design options. 

This section focuses on the first phase of the ERA modeling work, namely 

establishing models for the teardown products based on the current energy test procedure. 

These models were later adjusted to represent baseline energy use under the new test 

procedures, and these models were used subsequently to calculate energy savings 

potential. The baseline analysis results were compared with available data to assure that 

the models provide accurate representation of product energy use. This section discusses 

the creation and calibration of the ERA energy models, the metrics which were 

compared, and the adjustments which were made in some cases in order to improve 

calibration. 

Input data for energy modeling was collected during the reverse engineering 

phase of the project. Collection of this data is discussed in Section 5.5.3.2 above. For 

products which DOE arranged to have energy tested, additional information was 

available for certain model parameters, such as defrost heater on times, compressor run 

time between defrosts, evaporator exit superheat, etc. Performance data was obtained 

from compressor vendors for the compressors used in the teardown products, as well as 

for compressors which could be considered as alternative options to reduce energy use. 

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EERE-2008-BT-STD-0012 COMMENT 20
Initial energy models were created, and the models were subsequently adjusted to 

provide a best match with available data for product performance. Key sources of 

information used for calibration of the energy models were the product EnergyGuide 

labels and data from energy tests carried out for a number of the reverse engineering units 

(Section 5.5.5). Energy test parameters besides energy use which were examined include 

compressor running power input, duty cycle, evaporating temperature, and condensing 

temperature. Since not all ERA input parameters can be determined definitively based on 

available information, some of the inputs were adjusted within reasonable ranges in order 

to provide good matches between model results and other performance indicators. It is 

recognized that energy levels reported in the EnergyGuide can be conservative to provide 

margin for variation in the production process. Hence, it is expected that ERA results 

would more likely be lower than the EnergyGuide value than higher. 

In some cases the directly modeled energy use was significantly lower than actual 

product energy use, In some of these cases in which the system operating parameters 

could be well calibrated based on test data, DOE attributed the high actual duty cycle and 

energy use to high actual cabinet thermal load. A number of factors could possibly 

explain such results, including greater impact than expected of thermal short circuits 

associated with wiring harnesses and other design details, excess gasket region load, and 

consistently lower insulation thermal performance than expected. A consistently 

underperforming compressor model could also explain such a discrepancy, but DOE 

concluded that this explanation is less likely than factors which would increase cabinet 

thermal load. Hence, for these cases, additional cabinet load was added to result in an 

energy use and compressor duty cycle which provided reasonable agreement with the 

available data. The side-mount refrigerator-freezers (product classes 4 and 7) were 

adjusted using this approach. 

In some cases, DOE concluded that ERA was not modeling particular heat 

exchangers properly. Adjustments were made in which the calculated effective surface 

area of the heat exchanger was adjusted upwards or downwards to represent heat transfer 

performance different than modeled. These adjustments were made to achieve more 

reasonable match of evaporating or condensing temperatures. Similar adjustments were 

made in some cases to evaporator pressure drop to adjust for an apparent discrepancy 

between measured evaporator surface temperature and compressor power input. 

The ERA analysis results after adjustments of the model input for the seven key product 

classes analyzed are compared with the EnergyGuide data and Energy test results in 

Figure 5.7.1 for refrigerator-freezers, in Figure 5.7.2 for standard-size freezers, and in 

Figure 5.7.3 for compact refrigerators and freezers. Energy testing was performed on a 

limited group of freezers and compact products: one upright freezer, one chest freezer, 

and one compact refrigerator. For these figures, the energy use of the freezers has been 

adjusted consistent with the energy test by applying the 0.85 correction factor for upright 

freezers and the 0.7 correction factor for chest freezers. 

The energy models are within a few percent of the EnergyGuide labeled energy use with 

one key exception, the 1.7 ft3 compact refrigerator. For this unit, the roughly 15% 

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EERE-2008-BT-STD-0012 COMMENT 20
discrepancy with the EnergyGuide energy use was not reconciled. Because the measured 

energy use also differed significantly from the rated energy use for this product, DOE 

could not draw firm conclusions regarding system operation in order to assist in the 

calibration effort. DOE expects that both the cabinet and system for this product are 

operating less efficiently than modeled. 

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Labels and Energy Test Measurements 

5-38
 

EERE-2008-BT-STD-0012 COMMENT 20
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Figure 5.7.2 ERA Analysis for Freezers Compared with EnergyGuide Labels and 

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EnergyGuide Labels and Energy Test Measurements 

5-39 

EERE-2008-BT-STD-0012 COMMENT 20
5.7.4	 Adjustments to Energy Models to Represent Baseline Products Tested Under 

the Proposed Test Procedure 

This section discusses adjustment of the calibrated baseline ERA models to 

address two issues: (1) modification of some of the modeled product designs so they 

represent baseline-efficiency products of the desired product classes, and (2) adjustment 

for the proposed test procedure changes. 

Modifications were made to some of the modeled product designs so that they 

represent baseline products of the product classes of interest with appropriate typical 

characteristics. The changes made are discussed in the following paragraphs. 

Some of the teardown products purchased were not available as baselineefficiency products, i.e. products with energy use that is minimally compliant with the 

current energy standards. This was true primarily for product class 5, refrigerator-freezers 

with automatic defrost and bottom-mounted freezers without TTD ice service. As 

indicated above in Table 5.5.2, one of these products had energy use roughly 15% below 

the maximum allowable energy use (the former ENERGY STAR level), and the others 

had energy use at 20% below (the current ENERGY STAR level). In order to allow the 

engineering analysis to examine the cost associated with the efficiency improvement 

from the 0% to the 15% and 20% efficiency levels, a baseline model was created for a 

product which would be minimally compliant with the standards. This was done by 

carrying out the engineering analysis in reverse, removing the less cost-effective design 

options first, in order to achieve calculated energy levels consistent with the baseline 

energy standard. 

For product class 5, baseline models were established to represent products with 

French Doors. Comments made at the framework meeting and submitted to DOE as part 

of the framework comment period addressed this issue, as discussed in chapter 2. Most of 

the teardown products were purchased prior to the framework meeting, so DOE was not 

able to consider this issue when selecting these products. The two French Door products 

(see Table 5.5.2) were purchased later, to allow investigation of the different design 

details for these products. However, these French Door products are not product class 5, 

since they have TTD ice service. During the manufacturer interviews, DOE learned that 

more than half the sales of product class 5 currently have French Doors. As a result, DOE 

has used a French Door design as the basis for the engineering analysis for this product 

class. Because neither the products initially purchased for teardown nor the French Door 

products purchased later strictly fit the intended baseline design configuration, 

adjustments were made to establish product class 5 French Door designs for the 

engineering analysis. This was done for the 25 ft3 product by developing and adjusting an 

energy model for one of the 25 ft3 product class 5A reverse engineering units and for the 

18.5 ft3 product by adding French Door design features to the initial baseline model for 

the 18.5 ft3 product class 5 reverse engineering unit. Development of the product class 5 

French Door models involved the following considerations and steps. 

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EERE-2008-BT-STD-0012 COMMENT 20
 

 

French door refrigerator-freezers generally require electric anti-sweat heaters to 

prevent condensation of moisture on the gaskets and/or flip-mullions which seal between 

the French doors, since refrigerant-line anti-sweat heating is not possible in this region. 

The electric anti-sweat heater power input for the models was set at 6 W total, in spite of 

information that these heaters can have higher wattage input. The maximum timeaveraged heat input for a warm refrigerant liquid anti-sweat heater is typically somewhat 

lower per length,g

 suggesting that a wattage level of 6 W should be sufficient. DOE did 

not have adequate information regarding the thermal characteristics of the French Door 

gasket in order to allow a more refined estimate. DOE developed the baseline product 

design parameters assuming that the energy use is the average of tests with the anti-sweat 

heater on during one test and off during another.h 

Gasket load for the fresh food compartment was increased to account for the 

additional gasket region length. This was added to the single-door 18.5 ft3 product class 5 

model, but was already part of the baseline for the fresh food compartment doors of the 

25 ft3 product class 5A model. The freezer compartment of the 25 ft3

 product class 5A 

teardown model had two drawers. Hence, the energy model representing this product as 

received incorporated an increase in the freezer compartment gasket load to account for 

the additional gasket length. When establishing the baseline ERA model for subsequent 

design option analysis, the added gasket load representing the two drawers was removed 

from the model. DOE took this step in order to establish a baseline model representing a 

single freezer drawer. 

The loads associated with the TTD ice system of the 25 ft3 product class 5A 

baseline were eliminated to create the 25 ft3 product class 5 with French Doors model. 

This includes the loads of the ice chute penetration, as well as the loads associated with 

the duct which conveys cold freezer air to the ice maker compartment. Additional loads 

and energy use associated with heaters in the region of this duct never entered into the 

model, because DOE understands that the teardown product was tested in a fashion which 

prevented activation of these heaters. 

Different compressor efficiency levels were selected and/or different fan motor 

types were selected in order to achieve modeled energy use consistent with the energy 

conservation standard. 

DOE obtained the product class 4 teardown unit (refrigerator-freezer with 

automatic defrost and side-mounted freezer without TTD ice service) with the 

understanding that it had TTD ice service. To address this discrepancy in the energy 

g

 For example, if the liquid flow of an 800 Btu/h nominal capacity compressor is cooled from a condenser 

exit temperature of 110  ̊F down to an ambient temperature of 90  ̊F, the delivered heat load during 

compressor operation is 70 Btu/h. Assuming roughly 50% duty cycle and 13 ft of freezer perimeter (the 

typical location for warm liquid anti-sweat), the heat per linear foot is 10.8 Btu/h-ft, equivalent to 3.2 W/ft. 

h

 As discussed in Chapter 3, the DOE energy test procedure calls for calculation of refrigerator energy use 

based on a test with anti-sweat heater switch in the on position. However, DOE understands that many if 

not all manufacturers calculate energy use as the average of tests with the switch in the on position and the 

off position. DOE expects to propose changing the test procedure to allow averaging of the two tests in the 

ongoing test procedure rulemaking. 

5-41
 

EERE-2008-BT-STD-0012 COMMENT 20
modeling work, the initial baseline model for the product was modified to represent 

product class 7 (refrigerator-freezer with automatic defrost and side-mounted freezer with 

TTD ice service). This was done by adding load and additional electric anti-sweat heat 

appropriate for the TTD feature. 

The engineering analysis has been carried out based on the expected revised 

energy test procedure, which includes modified cabinet temperatures as discussed in 

Section 5.4.2. After calibration of the ERA models with EnergyGuide and energy test 

data according to the current energy test procedure, and after the adjustment to the 

models to better represent the products under investigation as described above, the ERA 

models were adjusted to represent operation under the new energy test procedure. This 

adjustment did not apply to the freezers, since there are no proposed changes to the 

freezer compartment temperatures. The calculated impact of the compartment 

temperature changes on the energy use is discussed in Section 5.4.2.1 and is shown in 

Table 5.4.8 of that section. This calculated impact of the temperature changes is fairly 

consistent with the results provided by AHAM, although it is less than the impact 

measured during DOE testing of the teardown products. 

5.8 DESIGN OPTIONS 

After conducting the screening analysis described in chapter 4, DOE considered 

the remaining technologies in the design option analysis. Table 5.8.1 lists the design 

options considered for each product classes. Some design options are only applicable to 

certain types of equipment. Following the table is a description of how each of the design 

options was applied during the engineering analysis. See chapter 3 for background 

descriptions of the technologies. 

5-42
 

EERE-2008-BT-STD-0012 COMMENT 20
 

 

 

 

 

 

 

 

 

Table 5.8.1 Design Options by Product Class 

Design Option PC3 PC5 PC7 PC9 PC10 PC11 PC18 

Increased Insulation 

Thickness 

9

1 in 

9

1 in 

9

3/4 in 

9

3/4 in 

Vacuum-Insulated 

Panels 

9 9 9 9 9 9 9

Improved Compressor 

Efficiency 

9 9 9 9 9 9 9

Variable-Speed 

Compressor 

9 9 9 9 9 9 9

Increased Evaporator 

Surface Area 

9 9 9 9 9 9

Increased Condenser 

Surface Area 

9 9 9 9 9

Forced Convection 

Condenser 

9

Brushless DC 

Evaporator Fan 

9 9 9 9

Brushless DC 

Condenser Fan 

9 9 9 9

Adaptive Defrost 9 9 9 9

Variable Anti-Sweat 

Heater Control 

9

5.8.1 Increased Insulation Thickness 

Manufacturers stated during discussions that the potential for insulation thickness 

increases is very limited for many product classes. Greater insulation thickness would 

result in either decreased interior volumes, increased exterior dimensions, or some 

combination of both. They cited the high percentage of the market associated with 

replacements and the fixed sizes available for replacement refrigerators in consumers’ 

kitchens. The 1995 TSD supporting the 1997 refrigerator energy conservation standard 

final rule provided information regarding the reduction in served market associated with 

exterior size increases.9

 Reduction in internal volume is undesirable because this is a key 

selling feature. As a result, DOE did not consider insulation thickness increase in the 

analysis for standard-size refrigerator-freezers. 

There is some more flexibility in the potential to increase insulation thickness for 

freezers, since freezers are less likely to be placed in fixed-dimension spaces in kitchens. 

DOE did consider insulation thickness increase of up to 1 inch for standard-size freezers. 

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EERE-2008-BT-STD-0012 COMMENT 20
Compact refrigerators often have limitations on potential for size increase. 

However, many compact refrigerator products currently have insulation thickness no 

more than an inch. The potential energy benefit of insulation thickness increases for these 

products is significant. Hence, DOE considered increases of up to 3/4 inch for these 

products. DOE considered increase up to 3⁄4 inch also for compact freezers. 

While a manufacturer’s approach to implementing insulation thickness increase 

would likely involve a combination of reduced internal volume and increased external 

dimensions, DOE used just external dimension increase. This was done to assure that the 

product size (represented by adjusted volume) and the associated baseline energy use for 

the product did not change as the design options were applied. 

Costs associated with insulation thickness increases were calculated using the 

manufacturing cost model. As discussed in Section 5.6.6, DOE applied a conservative 

treatment of depreciation costs in which additional cost equal to the greenfield 

depreciation cost per product was added in order to reflect the likely build of a new 

production facility. DOE assumed that the depreciation cost would be incurred for any 

increase in insulation thickness. However, DOE allowed for increases in the door 

thickness without applying depreciation costs associated with the cabinet, and vice versa. 

Initial manufacturing cost model calculations provided the total cost impact of 

increasing all of the insulation in the product by a single amount. In order to allocate the 

cost increase to the cabinet and the door, DOE assumed that the cost of increasing the 

insulation thickness of the door was 5% of the total. This allocation was applied to both 

direct costs and depreciation costs. 

5.8.2 Vacuum-Insulated Panels 

Vacuum-insulated panels (VIPs) increase efficiency by significantly increasing 

the thermal resistivity of the cabinet walls, and therefore decreasing heat penetration into 

the cabinet. DOE considered the addition of 1⁄2-inch thick VIPs to the walls and doors of 

the cabinet for all product classes, and the remainder of the insulation thickness was filled 

with PU foam. Data for VIP thermal characteristics and costs were provided by va-Q-tec, 

a VIP manufacturer. The cost information was confirmed through discussions with 

manufacturers. In these discussions, manufacturers pointed out that edge effects can 

result in actual performance significantly less than predicted. However, DOE considers 

that thermal performance estimates based on the va-Q-tec technology are more accurate 

than for other VIP options because this technology has a more modest mid-panel thermal 

resistance and a significantly thinner metallic layer than other options. The mid-panel 

conductivity of this VIP technology is 3.5 mW/m-C (0.024 Btu-in/sqft-hr- ̊F).10 In 

contrast, the conductivity of PU foam is in the range 0.13 to 0.14 Btu-in/sqft-hr- ̊F. 

As discussed in Section 5.7.2, thermal performance of composite walls including 

VIPs was done using composite wall average thermal resistivities. The composite wall 

resistivity Rw was calculated as follows. 

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EERE-2008-BT-STD-0012 COMMENT 20
(R t + R t ) VIP VIP PU PU Rw = (tVIP + tPU )

Where RVIP and RPU are the thermal resistivities of the VIP and the PU foam, and 

tVIP and tPU are the thicknesses of the VIP and PU foam layers. The thermal resistivities 

for the materials are the inverses of the conductivities. 

DOE analysis of cabinet load reduction achievable through the use of VIPs using 

this analysis approach is consistent with analysis carried out by va-Q-tec and also 

consistent with prototype testing using VIP technology. The reduction in cabinet load 

possible using VIPs for a refrigerator-freezer with typical wall thickness is roughly 30%, 

which is consistent with results reported by Electrolux for use of vacuum insulation in 

freezers.11 

The following cost information, which va-Q-tec provided and/or which DOE 

developed based on subsequent discussions, formed the basis of the applied costs for 

VIPs. 

• Average panel cost $3.08/ft2

 at 1.2 cm thickness. 

• Fill cost as a percent of panel cost 60%. 

• Added glue cost for adhering the panel to cabinet surfaces 5% of panel cost. 

• Cost savings associated with displaced PU foam 2.5% of panel cost. 

In order to allow calculation of costs for other VIP thicknesses, the fill cost is 

considered proportional to the thickness, while the remaining cost per square foot is 

constant. In addition, direct labor cost associated with application of the panel to cabinet 

and door surfaces was calculated based on the $24/hr wage rate (including fringe 

benefits) discussed in section 5.6, and time for application of 10 minutes for a 

compartment and 1 minute for a door. The direct material and labor costs associated with 

use of the VIP must be adjusted to account for capital expenses and overhead associated 

with incorporation of VIPs into the production process. Because the material cost of VIPs 

is currently high in relation to the costs of other materials used in the manufacture of 

refrigerators and freezers, the cost adders for overhead and depreciation discussed in 

Section 5.6.6.1 and shown in Table 5.6.5 were divided by two in order to provide more 

reasonable representation of these costs for this technology. Hence, DOE used the 

following percent additions: 11.7% for standard-size refrigerator-freezers, 14.2% for 

standard-size freezers, and 19.6% for compact refrigerators. 

5.8.3 Improved Compressor Efficiency 

DOE considered the substitution of higher efficiency compressors for all product 

classes. This design option was often applied in two stages if there was a large gap 

between the baseline energy efficiency ratio (EER) and the maximum available EER for 

a given compressor capacity. DOE acquired compressor performance data from 

compressor vendors for use in the energy analysis, including capacity and power input for 

the applicable range of combinations of suction and discharge pressure conditions. As an 

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EERE-2008-BT-STD-0012 COMMENT 20
 

0

1

2

3

4

5

6

7

0 200 400 600 800 1000

E

E

R

(

B

t

u

/

h

W

)

Capacity (Btu/h)

Single Speed

Variable Speed at Lowest Speed

Variable Speed at 3000 rpm

example of the potential for improvement, standard-size baseline refrigerator-freezers 

typically use compressors with a rated EER of 5.0 to 5.5 Btu/h-W. DOE considered 

improved EERs of 5.75 through 6.25 Btu/h-W. 

Currently the highest EER compressor commercially available is rated near 6.25 

Btu/h-W for standard- size refrigerator-freezers. The range of available compressor 

efficiencies is illustrated in Figure 5.8.1 below. The peak available efficiency level does 

not vary significantly for the range of capacities typical for standard-size refrigeratorfreezers (600 to 800 Btu/h). However, efficiency level drops off considerably for smaller 

capacity compressors that are generally used in compact refrigerators and freezers. 

‐

Figure 5.8.1 Compressor Efficiency Data 

Estimates for increased cost of higher-efficiency compressors used for standardsize refrigerator-freezers and standard-size freezers were received from compressor 

vendors. These estimates were also discussed with manufacturers. Based on this 

information, DOE developed a curve for the cost premium associated with higher 

efficiency compressors. This curve is shown in Figure 5.8.2 below. 

5-46
 

EERE-2008-BT-STD-0012 COMMENT 20
Figure 5.8.2 Incremental Cost for Single-Speed Compressors for Standard-Size 

Products 

When considering compressor efficiency improvement for standard-size products, 

DOE used the performance data of specific higher-efficiency compressors in the energy 

analysis. The alternative compressors were selected to have nearly the same capacity as 

the baseline compressors, in order to assure nearly identical performance except for 

compressor power input. 

In the analysis of compressor efficiency improvements for compact products, an 

approach was required which addressed the reduction of compressor efficiency as the 

capacity is reduced. A curve roughly representing the maximum available EER for 

smaller compressors was developed. This curve is compared in Figure 5.8.3 below with 

the data for commercially available compressors. 

5-47
 

EERE-2008-BT-STD-0012 COMMENT 20
0

1

2

3

4

5

6

0 100 200 300 400 500 600

E

E

R

(

B

t

u

/

h

‐

W

)

Capacity (Btu/h)

CompressorData

Maximum EER Curve

Figure 5.8.3 Efficiency Curve for Low Capacity Compressors 

To model energy use of higher efficiency low-capacity compressors, DOE 

reduced the power input data for the baseline compressor by a selected factor so that the 

rated EER matches the maximum EER of the above curve. The baseline compressors of 

the products analyzed had EERs typically 0.5 to 1 Btu/h-W lower than the maximum 

curve shown in the figure above. 

DOE received vendor cost estimates for efficiency improvements for lowcapacity compressors. DOE also received information on the typical cost increase during 

discussions with manufacturers of products which use these compressors. A 

representative cost estimate of $10 per 1.0 Btu/h-W efficiency improvement was used in 

the analysis. 

5.8.4 Variable-Speed Compressor 

Variable speed compressors (VSC) operate at multiple speeds to allow variation 

of compressor capacity. They also generally use permanent magnet motors, which can be 

more efficient than induction motors for the power level required for residential 

refrigerator compressors. They improve efficiency by (1) use of the higher-efficiency 

motor technology, (2) increasing the operating effectiveness of heat exchangers because 

there is lower mass flow being cooled or warmed by a fixed-size heat exchanger, and (3) 

reducing cycling losses by reducing the number of cycles. VSC technology has been 

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EERE-2008-BT-STD-0012 COMMENT 20
available for many years and a number of refrigerator-freezer products currently use the 

technology. Currently nearly all of these products use Embraco VSCs. DOE obtained 

compressor performance data for the range of sizes of Embraco VSCs. This information 

was used in the energy analysis. DOE selected VSC capacities to nearly match those of 

the replaced single speed compressors at 3000 rpm. The lowest available speed for the 

Embraco VSCs is 1,600 rpm. The compressor typically cycles at the low speed to 

maintain internal setpoints for energy test conditions. DOE primarily used the 

performance data for 1,600 rpm in the energy analyses. The performance of VSC 

compressors at the lowest speed and at 3,000 rpm is shown in Figure 5.8.1 above. 

In order to maximize the energy benefit of VSCs, a design typically needs to 

address the impact that longer run time at lower capacity has on fan energy use. The 

increase in fan energy use can negate much of the reduction in compressor energy use. As 

a result, it is typically necessary to use brushless DC fan motors. In addition, the speed of 

brushless DC fan motors can be varied, depending on the design configuration. DOE is 

not aware of brushless DC fan motors designed for 120 VAC power input which allow 

adjustment of fan speed, although such a design should be viable. Most designs 

incorporating fan speed control use DC-input power for the fans and require a control 

system which can provide the DC power and vary it to adjust fan speed. Not all of DOE’s 

analysis involved optimization of fan speed and power with the variable speed 

compressor system. Some of the analyses involved selection of 50% fan speed, and some 

of the anlyses involved selection of speed to achieve roughly 50% power input. The cube 

law for fan power was used to calculate power input, except that at the 1/8 power level 

associated with the 50% fan speed, this power level was doubled. 

Cost estimates for the switch to variable speed compressors were provided by 

Embraco, and cost estimates were also obtained during discussions with manufacturers. 

An average of cost estimates provided by the manufacturers weighted by manufacturer 

market share is very near $50, not including additional changes which might be required 

to implement a variable speed system. DOE used a $50 cost increase in the analyses. 

Additional costs associated with conversion of a refrigeration system to variable speed 

operation are associated with a switch to brushless DC fan motors and the use of a control 

system sophisticated enough to provide adequate or optimized control. The Embraco 

VSC design includes a control system which can be used with a conventional mechanical 

thermostat. This system has been implemented in a commercially available freezer.12 The 

Embraco control adjusts speed based on the response of the mechanical thermostat. DOE 

considers that this approach is suitable for products with manual defrost. For products 

with automatic defrost and especially adaptive defrost, it is not reasonable to expect that 

that the Embraco system alone would be suitable. DOE included in cost estimates an 

additional $25 for addition of an electronic control system for products with automatic 

defrost. For product classes for which a significant portion of current models already 

have electronic control (product classes 5 and 7), analysis was conducted for an 

electronic control unit and a mechanical control unit. The average results for these 

product classes were weighted averages based on the distribution of electronic control for 

the product class. The current electronic percentages were selected based on input from 

manufacturers as 50% for side-mounts and 75% for bottom-mounts. The additional cost 

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associated with conversion to brushless DC fan motors did not generally apply: because 

brushless DC fan motors are more cost effective than a full conversion to variable speed, 

the cost of the motors would have already been applied at a lower efficiency levelwhen a 

change to variable speed is considered. 

5.8.5 Increased Evaporator Surface Area 

The evaporator is necessary for transferring heat from the cabinet to the 

refrigerant. Larger surface area allows the heat transfer to occur more efficiently. DOE 

considered an increase in evaporator surface area for all products analyzed. In some cases 

the size increase was limited by available space. This was true especially for the chest 

freezers and compact refrigerators. DOE considered size increases of up to 20%, except 

for one of the upright freezer models, for which DOE considered an increase of up to 

50%. The size increases were implemented in the energy analysis through increase of the 

effective heat exchanger surface areas and refrigerant pressure drops entered into the 

ERA model. The pressure drop increases as well as the surface area because the 

refrigerant tube length would be increased to maintain fin efficiency. 

Treatment of the cost of the evaporator size increase depended on the evaporator 

type. For forced convention and roll bond evaporators, the baseline costs of the 

evaporators were adjusted upwards by the size increase factor. For cold wall evaporators, 

the cost increase was directly calculated in the manufacturing cost model by increase of 

the tube lengths and materials associated with providing good tube/liner thermal contact. 

5.8.6 Increased Condenser Surface Area 

The condenser transfers heat from the refrigerant to the ambient air. Larger 

surface area allows the heat transfer to occur more efficiently. DOE considered an 

increase in condenser surface area for all products analyzed. In some cases the size 

increase was limited by available space. This was true especially for hot wall or static 

condensers. DOE considered size increases of up to 20%. The size increases were 

implemented in the energy analysis through increase of the effective heat exchanger 

surface areas and refrigerant pressure drops entered into the ERA model. The pressure 

drop increases as well as the surface area because the refrigerant tube length would be 

increased to maintain fin efficiency. 

Treatment of the cost of the condenser size increase depended on the condenser 

type. For forced convention and static condensers, the baseline costs of the condensers 

were adjusted upwards by the size increase factor. For hot wall condensers, the cost 

increase was directly calculated in the manufacturing cost model by increase of the tube 

lengths and materials associated with providing good tube/shell thermal contact. 

5.8.7 Brushless DC Fan Motors 

Brushless DC fan motors are more efficient than the shaded pole motors which 

are often used in baseline model refrigerators. 

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EERE-2008-BT-STD-0012 COMMENT 20
In the TSD supporting the 1997 refrigerator energy conservation standard final 

rule, shaded pole fan motor power input ranging from 8 to 12 W was assumed to be 

reduced to 4.5 W when switching to brushless DC motors.9

 This is a reduction in power 

ranging from 44 to 57%. The cost increase of that analysis associated with the switch was 

$6.50 for an evaporator fan and $4.50 for a condenser fan. 

The fan power input measured for the teardown products are summarized in Table 

5.8.2 below. For the baseline/ENERGY STAR product pairs, power input is provided for 

both sets of each applicable fan. The fan motor power reduction associated with the 

switch to brushless DC motors based on this data is in the range 60% to 65%. 

Table 5.8.2 Teardown Product Fan Power Input 

Product Evaporator Fans Condenser Fans 

21 ft3 Top-Mount** 

Shaded Pole 

5.7, 6.1 

Brushless 

DC 

NA 

Shaded Pole 

9.4 

Brushless 

DC 

3.3 

26 ft3 Side-Mount** 5.6, 5.8 NA 8.5 3.4 

25 ft3 Bottom Mount 1 6.5 NA NA 3.7 

18.5 ft3 Bottom Mount 6.2 NA NA 3.8 

25 ft3 Bottom Mount 2 NA 3.25* NA 2.2* 

22 ft3 Side-Mount NA 3.25* 9.1 NA 

20 ft3 Upright Freezer** 11.5 4.5 NA NA 

14 ft3 Upright Freezer 7.4 NA NA NA 

*DC-input fan. The listed wattage is nominal. 

**Data provided for a baseline/ENERGY STAR product pair. 

DOE also obtained information on typical fan motor power reduction associated 

with a switch to brushless DC motors during discussions with manufacturers. The 

responses indicated that the reductions would be more modest than suggested by the 1995 

TSD values or the measurements of teardown products. DOE selected a compromise 

power reduction of 50% when the possible reduction was not already clearly illustrated 

by the measurements of the baseline/ENERGY STAR teardown product pairs under 

analysis. 

Incremental cost estimates for the switch to brushless DC motor were obtained 

through discussion with Matsushita, a key vendor supplying these motors, and through 

discussions with manufacturers. DOE used incremental cost estimates of $3.75 for 

condenser fans and $3.50 for evaporator fans. 

5.8.8 Adaptive Defrost 

An adaptive defrost system adjusts the time interval between defrosts based on 

some indication of the need for defrost. A common indicator is the length of time 

required to complete the previous defrost. Other indicators could include the number of 

door openings or a measurement of ambient humidity. DOE considered this design option 

for product classes which have automatic defrost (product classes 3, 5, 7, and 9). The 

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EERE-2008-BT-STD-0012 COMMENT 20
ERA model allows input of compressor run time between defrost. To model this option, 

DOE increased the compressor run time between defrosts to 38 hours, as compared to the 

typical range for baseline products of 10-15 hours. The 38 hours is the default time 

interval allowed by the test procedure if the mean time between defrost test is not carried 

out, assuming default values of the minimum and maximum compressor run intervals of 

12 and 84 hours. 

Based on discussions with manufacturers, DOE used an incremental cost of $8 in 

the energy analysis for adaptive defrost. This cost assumes use of a standalone adaptive 

defrost controller, which could be used if the refrigerator does not already have electronic 

control. Refrigerators which have electronic control can implement adaptive defrost with 

programming changes which incur no per-unit cost. For some products for which a 

significant portion of current shipments already have electronic control, the incremental 

cost for adaptive defrost was multiplied by the fraction of products of the product class 

which do not already have electronic control, as was done for the electronic control cost 

addition for variable speed compressors. 

In cases where both adaptive defrost and variable speed compressor design 

options were analyzed, the cost of the adaptive defrost was eliminated, because the 

introduction of electronic controls would make use of a standalone adaptive defrost 

controller unnecessary. 

5.8.9 Variable Anti-Sweat Heater Control 

Variable anti-sweat heater control adjusts the time-average wattage of an electric 

anti-sweat heater based on ambient temperature and humidity conditions so that all 

surfaces are just above the ambient dew point. DOE considered this option for bottommount French-door refrigerator-freezers (PC 5). These products must use electric antisweat heaters in the region of the seal between the two fresh food doors to control 

condensation, because warm liquid anti-sweat heating cannot be applied in this region. 

Most modern refrigeration products use warm liquid anti-sweat heating, thus making 

electric anti-sweat heaters unnecessary, except in such locations. To model the energy use 

reduction associated with this design option, DOE established a curve representing the 

heater power input as a function of ambient humidity. DOE then calculated annual 

average electric anti-sweat heater wattage based on the frequency distribution of 

humidity levels established in the GE waiver describing a test procedure for this control 

scheme.13 The selected DOE curve is based on power levels of 0W at 65% RH and 9W at 

100% RH. The maximum power was increased as compared with the 6W used for the 

anti-sweat heater for the baseline product analysis (see the discussion in Section 5.7.4), 

because the variable anti-sweat heater control minimizes the energy use impact of the 

higher wattage. 

Implementation of variable anti-sweat heater control requires use of a humidity 

sensor and an electronic controller which can adjust the time-average heater wattage 

appropriately. For products which already have electronic control, DOE used the cost just 

of a humidity sensor. DOE used a cost of $9.48 for a Honeywell humidity sensor based 

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EERE-2008-BT-STD-0012 COMMENT 20
on high-quantity pricing.14 No product currently exists which provides standalone 

variable anti-sweat heater control. However, DOE considers the $8 example of the 

standalone adaptive defrost controller to be representative of the incremental cost of such 

a product. 

5.8.10 Forced Convection Condenser 

A forced convection condenser can be more efficient than a hot wall condenser, 

because it enables more effective heat transfer from the refrigerant to the ambient air. 

DOE considered this option for upright freezers only (product class 9). This conversion 

involves the addition of a typical wire-tube condenser, a fan assembly, wiring to power 

the fan, and a warm liquid anti-sweat heating loop, and the elimination of hot wall tubing 

on the insulation side of the outer shell. In the case of the upright freezer products 

examined for the reverse engineering work, there was ample space underneath the cabinet 

for the condenser and fan assembly. In addition, these products incorporated hot gas 

condensate pan heaters. These heaters could be eliminated in a forced-convection 

arrangement, because the condenser heat and air flow of the forced convection 

arrangement would be sufficient to evaporate the condensate, as is generally done for 

refrigerator-freezers. DOE used a net incremental cost of $3 for this conversion—most of 

the cost of the added components would be saved through elimination of the hot wall 

condenser. DOE analyzed this design option both with shaded pole and brushless DC 

condenser fans. The option provided an energy benefit in combined design option 

analysis only when using the brushless DC fan motor. 

5.9 ENGINEERING ANALYSIS RESULTS 

This section shows the incremental cost curves developed by DOE and provides 

comparison to the data provided by AHAM. 

5.9.1 DOE Cost-Efficiency Curves 

DOE generated cost-efficiency curves for two product volumes in each of the 

seven analyzed product classes based on combinations of individual design options. The 

curves were normalized by converting to costs at specific efficiency levels (every 5% 

energy use reduction from 10% to 45%) for simplified downstream analysis. 

Conversion of cost curves to the specified efficiency levels was complicated by 

the characteristics of the design options required to provide further efficiency 

improvement. Some design options can be partially applied, while others cannot. For 

instance, for the 21 ft3 top-mount refrigerator, the second step in the design option path 

raises the efficiency level from 9.9% to 16.8% by increasing the compressor EER from 

5.54 to 6.08 Btu/h-W. The cost for compressor efficiency improvement, illustrated in 

Figure 5.8.2, varies as the efficiency varies. Because intermediate efficiency level 

compressors are generally available, the cost to achieve a fraction of the increase to 

16.8% would be a fraction of the cost to achieve the full step to 16.8%. Hence, DOE 

calculated the cost of raising efficiency to the 10% and 15% levels by calculating the 

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EERE-2008-BT-STD-0012 COMMENT 20
lower cost of partial improvement in compressor EER. In some cases, such as 

implementation of a variable speed compressor, the design option cannot be partially 

implemented. For these cases, the entire cost of the design option was applied at the 

intermediate efficiency level, even though the design might overshoot the efficiency 

level. This causes some of the incremental cost curves to have slopes which don’t 

increase monotonically. 

The DOE incremental MSP costs are presented in Table 5.9.1 below. While DOE 

analyzed two sizes of each product, it is not clear that differences in the curves can 

rightly be attributed to the size differences. Other factors likely have greater influence, 

for instance for product class 3 the 16 ft3

 product had noticeably thinner insulation than 

the 21 ft3

 product. DOE considers the averages of the MSPs to be representative for each 

product class. The separate analysis of the slopes of the energy use vs. adjusted volume 

curves discussed in section 5.4.2.3 addresses the issue of adjustments to more accurately 

reflect the impact that product size has on energy use. 

Table 5.9.1 DOE Incremental Costs 

Product Size* Efficiency Level 

Class (ft3

) 10% 15% 20% 25% 30% 35% 40% 45% 

16 $6.52 $11.21 $21 $49 $94 $127 $168 $208 

3 21 $0.47 $4.16 $11 $20 $31 $81 $145 $208 

Avg $3.50 $7.68 $16 $35 $62 $104 $156 $208 

5 

18.5 $7.21 $16.34 $26 $36 $58 $119 $177 $243 

25 $0.00 $2.27 $9.49 $30 $41 $107 $185 $254 

Avg $1.80 $5.79 $14 $31 $45 $110 $183 $251 

7 

22 $9.92 $23.45 $76 $139 $203 $264 $359 N/A 

26 $12.44 $14.46 $32 $73 $131 $194 $262 $345 

Avg $11.18 $18.96 $54 $106 $167 $229 $311 N/A 

9 

14 $6.38 $6.38 $11 $34 $62 $90 $175 $259 

20 $6.43 $16.51 $17 $21 $31 $64 $73 $135 

Avg $6.41 $11.45 $14 $28 $47 $77 $124 $197 

10 

15 $0.00 $2.93 $8.90 $14 $18 $45 $51 $106 

20 $4.70 $9.16 $39 $45 $52 $104 $104 $168 

Avg $2.35 $6.05 $24 $29 $35 $74 $77 $137 

11 

1.7 $2.44 $4.70 $7.10 $19 $20 $29 $45 $61 

4 $4.28 $7.94 $10.61 $22 $23 $24 $33 $53 

Avg $3.36 $6.32 $8.85 $21 $22 $27 $39 $57 

18 

3.4 $5.42 $8.38 $32.54 $46 $63 $63 $63 $87 

7 $6.68 $10.93 $35.52 $39 $57 $63 $87 $92 

Avg $6.05 $9.65 $34.03 $43 $60 $63 $75 $90 

*These are total product volumes based on the current test procedure, not adjusted 

volumes. 

DOE did not attempt to provide distributions of costs at each efficiency level. 

While the MSP curves for the two different sizes for each product class provides some 

5-54 

EERE-2008-BT-STD-0012 COMMENT 20
$

$50

$100

$150

$200

$250

$300

$350

0% 5% 10% 15% 20% 25% 30% 35% 40% 45%

I

n

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P

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e

Efficiency Level

Product Class 3

Product Class 5

Product Class 7

indication of the variation of the costs, the full range is very likely much greater. There is 

insufficient information currently available for DOE to confidently calculate cost 

distributions at each efficiency level. The average curves for incremental manufacturer 

selling price are plotted in Figure 5.9.1 through Figure 5.9.3 below. 

‐

Figure 5.9.1 Incremental Manufacturer Selling Price for Standard-Size 

Refrigerator-Freezers 

5-55
 

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$

$50

$100

$150

$200

$250

0% 5% 10% 15% 20% 25% 30% 35% 40% 45%

I

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P

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Efficiency Level

Product Class 9

Product Class 10

‐

Figure 5.9.2 Incremental Manufacturer Selling Price for Standard-Size Freezers 

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$

$10

$20

$30

$40

$50

$60

$70

$80

$90

$100

0% 5% 10% 15% 20% 25% 30% 35% 40% 45%

I

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Efficiency Level

Product Class 11

Product Class 18

‐

Figure 5.9.3 Incremental Manufacturer Selling Price for Compact Refrigerators 

and Freezers 

5.9.2 AHAM Incremental Cost Data 

This section presents the aggregated incremental cost data provided by AHAM 

and discusses differences between this data and the incremental cost information 

developed by DOE. 

The data request sheets initially provided for the AHAM incremental cost data 

collection effort are in the framework document as Tables A-7A through A-7F of that 

document. The data collection effort was later modified to include a 35% efficiency level 

and to reduce the 15% efficiency level to 10% in order to provide an intermediate first 

level. Data was submitted to AHAM by manufacturers and this data was aggregated in 

preparation for submission to DOE, so that no reported data would represent responses 

from fewer than three manufacturers. 

Sufficient data was collected to allow reporting of incremental costs for product 

classes 3, 5, 7, 9, and 11, although for product classes 5 and 11 the reporting was for only 

one of the product sizes. 

After receipt of the data, DOE posed follow-up questions, some through AHAM 

and some directly with individual manufacturers, to improve understanding of the results. 

DOE requested that AHAM provide indication of what percent of shipments within each 

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product class was represented by reported information, so that the results for capital 

investments and one-time expenditures could more accurately be allocated to individual 

products. DOE also requested clarification regarding whether the capital investments and 

one-time expenditures reported for the two sizes of a product class would be added to 

provide total costs for the product class, or whether any portion of the cost would 

overlap. AHAM requested clarification on this question from members, and the response 

was that there is very little overlap in reporting of these costs. 

The following sections present the AHAM data and comparisons with DOE 

results by product class. 

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5.9.2.1 Product Class 3 

Incremental cost data for product class 3 refrigerator-freezers provided by AHAM 

are summarized in Table 5.9.2 below. 

Table 5.9.2 AHAM Incremental Cost Data for Product Class 3 

Efficiency Level 10% 20% 25% 30% 35% 

Product Class 3—15 ft3 

Incremental 

Cost 

Average 

(99%)* 

Material $13.02 $20.32 $90.79 $148.13 $160.19 

Labor $0 $0 $4.23 $8.72 $9.13 

Overhead $0 $0 $0 $0.04 $0.07 

CCE & OTPCE ($million) 

Total Industry 

Building CAPX 

(99%--4)* 

$0 $0 $3.5 $4.0 $4.5 

Tooling/Equipment 

CAPX (99%--4)* 

$0 $15.0 $25.2 $120.4 $125.5 

R&D (57%--3)* $0 $0 $4.5 $4.5 $17.5 

Marketing (57%--3)* $0 $0 $2.5 $2.5 $2.5 

ShipmentWeighted Average

Building CAPX $0 $0 $0.14 $0.14 $0.14 

Tooling/Equipment 

CAPX 

$0 $4.58 $6.75 $40.66 $40.69 

R&D $0 $0 $0.75 $0.75 $4.72 

Marketing $0 $0 $0.68 $0.68 $0.68 

Product Class 3—21 ft3 

Incremental 

Cost 

Average 

(99%)* 

Material $8.98 $22.09 $92.55 $150.79 $173.83 

Labor $0 $0 $4.22 $8.99 $8.99 

Overhead $0 $0 $0 $0.04 $0.04 

Minimum 

(57%)* 

Material $0 $8.27 $34.61 $43.60 $68.30 

Labor $0 $0 $0 $0.54 $0.54 

Overhead $0 $0 $0 $0.04 $0.04 

Maximum 

(57%)* 

Material $0.81 $10.18 $36.23 $46.93 Blank 

Labor $0 $0 $0 $0.55 $0.56 

Overhead $0 $0 $0 $0.04 $0.04 

CCE & OTPCE ($million) 

Total Industry 

Building CAPX 

(99%--4)* 

$0 $0 $3.0 $3.0 $3.0 

Tooling/Equipment 

CAPX (99%--4)* 

$0 $3.0 $65.5 $125.5 $130.5 

R&D (57%--3)* $0.5 $0.5 $2.5 $2.5 $12.5 

Marketing (57%--3)* $2.5 $2.5 $2.5 $2.5 $2.5 

ShipmentWeighted Average

Building CAPX $0 $0 $0.01 $0.01 $0.01 

Tooling/Equipment 

CAPX 

$0 $0.92 $19.05 $42.27 $42.27 

R&D $0.14 $0.14 $0.14 $0.14 $3.19 

Marketing $0.68 $0.68 $0.68 $0.68 $0.68 

CCE&OTPCE: Conversion Capital Expenditures and One-Time Product Conversion Expenses. Material, 

Labor, and Overhead are per unit. Blank entries indicate that there were insufficient responses for AHAM 

to provide data. 

*Percent of Product Class 3 shipments represented by these data and number of manufacturers represented 

(for capital and one-time expenditures). 

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EERE-2008-BT-STD-0012 COMMENT 20
 

 

The AHAM average incremental cost data for product class 3 refrigerator-freezers 

are compared with the DOE costs in Figure 5.9.4 below. The DOE costs in these curves 

have the manufacturer markup taken out so that they can be compared on a consistent 

basis. The AHAM curves include material, labor, overhead, and depreciation and onetime expenses. 

0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 

$200 

AHAM 21cuft AVG
 

AHAM 15 cuft AVG 

AHAM 21 cuft MIN/MAX 

DOE 21 cuft 

$150 DOE 16 cuft 

DOE AVG
 

t
 

s 

o
 

l

C

at

n $100 e
 

m
 er

c 

nI

$50 

$-

Efficiency Level (%) 

Figure 5.9.4 Incremental Cost Curves for Product Class 3 

Per-product incremental cost associated with capital expenditures and one-time 

expenses have been calculated as follows based on the AHAM data for these cost 

categories. Total reported industry expenditures for each of the four categories (building, 

equipment, R&D, marketing) are divided by the percent of shipments represented by the 

data as reported by AHAM to determine the total industry value of each of these 

expenditures. These values are then added to obtain the total one-time expenditures for 

the product class for each of the two product class sizes for which data was provided. The 

one-time expenditures for the small and large size products are added to obtain total 

product class one-time expenditures. For product classes for which data were reported for 

only one of the sizes (product classes 5 and 11), the total for the size is doubled to 

represent the total one-time expenditures for the entire product class. Allocation of the 

one-time expenditures is based on the projected shipments for the product class for the 

first 10 years of the life of the new standard as determined for the NIA. The expenditures 

are divided by the total of these shipments to determine the impact of one-time 

expenditures per unit. This value is then added to the incremental costs for the product 

represented by materials, labor, and overhead. 

5-60 

EERE-2008-BT-STD-0012 COMMENT 20
The data provided for the 21 ft3

 product class 3 refrigerator-freezers includes 

results for the average, the maximum, and the minimum cost data provided by 

manufacturers responding to the query for incremental cost data. Different numbers of 

responses were obtained for the average than for the minimum and maximum, as 

indicated in Table 5.9.2. The results for minimum and maximum, provided by 

manufacturers representing 57% of shipments for product class 3, are nearly equal. This 

suggests that the average cost data provided by these same manufacturers is nearly equal 

to these minimum and maximum values. The cost curve for these manufacturers, shown 

in Figure 5.9.4 with adjustments for capital and one-time expenditures, agrees very well 

with DOE results. The average cost data provided by the manufacturer(s) representing the 

remaining 42% of the product class shipments must have been quite high. 

In spite of the apparently good agreement between the DOE results and the 

AHAM data for the manufacturers who reported minimum and maximum incremental 

costs, there still remains a key discrepancy. DOE discussed the data submittals with some 

manufacturers after AHAM’s aggregation of the data, and the manufacturers reported that 

insulation thickness increases were considered as part of the design options associated 

with the data. Since DOE’s results did not consider insulation thickness increases, it 

would be expected that the DOE results would indicate higher costs. 

5-61
 

EERE-2008-BT-STD-0012 COMMENT 20
 

 

 

5.9.2.2 Product Class 5 

Incremental cost data for product class 5 refrigerator-freezers provided by AHAM 

are summarized in Table 5.9.2 below. 

Table 5.9.3 AHAM Incremental Cost Data for Product Class 5 

Efficiency Level 10% 20% 25% 30% 35% 

Product Class 5—19 ft3 

Incremental Cost Average 

(86%)* 

Material $2.23 $6.54 $48.82 $56.67 $86.17 

Labor $0.20 $0.25 $0.36 $0.71 $1.00 

Overhead $0.33 $0.46 $0.49 $0.65 $0.85 

Minimum 

(82%)* 

Material $1.86 $9.67 $51.24 $56.09 $85.59 

Labor $0.13 $0.20 $0.21 $0.26 $0.55 

Overhead $0.41 $0.62 $0.65 $0.82 $1.01 

Maximum 

(82%)* 

Material $1.86 $9.67 $51.24 $56.09 $85.59 

Labor $0.13 $0.20 $0.21 $0.26 $0.55 

Overhead $0.41 $0.62 $0.65 $0.82 $1.01 

CCE & OTPCE ($million) 

Total Industry 

Building CAPX 

(86%--4)* 

$0.1 $0.2 $0.5 $0.8 $1.0 

Tooling/Equipment 

CAPX (86%--4)* 

$0.3 $0.8 $31.0 $31.3 $36.5 

R&D (86%--4)* $0.9 $1.7 $3.2 $4.0 $12.3 

Marketing (86%--4)* $0.2 $2.7 $2.8 $2.8 $2.8 

ShipmentWeighted Average

Building CAPX $0 $0 $0 $0.01 $0.01 

Tooling/Equipment 

CAPX 

$0 $0.01 $7.74 $7.75 $8.00 

R&D $0.01 $0.52 $0.54 $0.56 $2.52 

Marketing $0 $1.71 $1.71 $1.71 $1.71 

CCE&OTPCE: Conversion Capital Expenditures and One-Time Product Conversion Expenses. Material, 

Labor, and Overhead are per unit. Blank entries indicate that there were insufficient responses for AHAM 

to provide data. 

*Percent of Product Class 5 shipments represented by these data and number of manufacturers represented 

(for capital and one-time expenditures). 

The AHAM incremental cost data for product class 5 is compared with the 

calculations carried out by DOE in Figure 5.9.5 below. The DOE costs in these curves 

have the manufacturer markup taken out so that they can be compared on a consistent 

basis. The AHAM curves include material, labor, overhead, and depreciation and onetime expenses. The AHAM and DOE data are in good agreement, except at the 25% and 

30% efficiency levels. However, as with product class 3, the agreement may not be 

entirely consistent because the DOE results did not consider insulation thickness 

increases. 

5-62
 

EERE-2008-BT-STD-0012 COMMENT 20
$-

$50 

$100 

$150 

$200 

$250 

I

n 

c 

r

e 

m 

e 

n 

t

a 

l

C

o 

s 

t 

AHAM 19 cuft AVG 

DOE 18.5 cuft 

DOE 25 cuft 

DOE AVG 

0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 

Efficiency Level (%) 

Figure 5.9.5 Incremental Cost Curves for Product Class 5 

5-63
 

EERE-2008-BT-STD-0012 COMMENT 20
 

 

 

 

 

5.9.2.3 Product Class 7 

Incremental cost data for product class 7 refrigerator-freezers provided by AHAM is 

summarized in Table 5.9.4 below. 

Table 5.9.4 AHAM Incremental Cost Data for Product Class 7 

Efficiency Level 10% 20% 25% 30% 35% 

Product Class 7—22 ft3 

Incremental Cost Average 

(97%)* 

Material $7.83 $52.26 $70.33 $84.58 $109.23 

Labor $0 $1.78 $3.56 $3.68 $3.80 

Overhead $0 $0 $0 $0.01 $0.03 

CCE & OTPCE ($million) 

Total Industry 

Building CAPX Blank Blank Blank Blank Blank 

Tooling/Equipment CAPX 

(97%--3)* 

$6.0 $6.0 $91.0 $91.0 $91.0 

R&D Blank Blank Blank Blank Blank 

Marketing Blank Blank Blank Blank Blank 

ShipmentWeighted Average

Building CAPX Blank Blank Blank Blank Blank 

Tooling/Equipment CAPX $1.32 $1.32 $17.48 $17.48 $17.48 

R&D Blank Blank Blank Blank Blank 

Marketing Blank Blank Blank Blank Blank 

Product Class 7—25 ft3 

Incremental Cost Average 

(97%)* 

Material $4.48 $11.60 $50.47 $50.62 $53.08 

Labor $0.03 $0.06 $1.89 $3.61 $3.65 

Overhead $0.07 $0.11 $0.12 $0.15 $0.21 

Minimum 

(80%)* 

Material $0.25 $1.81 $10.01 $3.55 $5.03 

Labor $0.02 $0.02 $0.02 $0.04 $0.05 

Overhead $0.05 $0.07 $0.07 $0.11 $0.15 

Maximum 

(80%)* 

Material $4.39 $37.43 $65.02 $13.94 $15.19 

Labor $0.03 $0.04 $0.14 $0.06 $0.07 

Overhead $0.09 $0.14 $0.15 $0.18 $0.22 

CCE & OTPCE ($million) 

Total Industry 

Building CAPX 

(80%--4)* 

$0.1 $0.2 $0.6 $21.0 $21.3 

Tooling/Equipment CAPX 

(97%--5)* 

$24.3 $25.2 $129.5 $242.4 $250.3 

R&D (80%--4)* $1.9 $2.0 $4.5 $8.0 $9.4 

Marketing (80%--4)* $2.7 $2.7 $2.8 $2.8 $2.8 

ShipmentWeighted Average

Building CAPX $0 $0 $0.09 $12.12 $12.16 

Tooling/Equipment CAPX $5.25 $5.25 $26.70 $66.41 $66.41 

R&D $0.45 $0.45 $0.46 $1.51 $1.51 

Marketing $1.50 $1.50 $1.50 $1.50 $1.50 

CCE&OTPCE: Conversion Capital Expenditures and One-Time Product Conversion Expenses. Material, 

Labor, and Overhead are per unit. Blank entries indicate that there were insufficient responses for AHAM 

to provide data. 

*Percent of the Product Class 7 shipments represented by these data and number of manufacturers 

represented (for capital and one-time expenditures). 

The AHAM incremental cost data for product class 7 are compared with the 

calculations carried out by DOE in Figure 5.9.6.The DOE costs in these curves have the 

5-64 

EERE-2008-BT-STD-0012 COMMENT 20
 

 

manufacturer markup taken out so that they can be compared on a consistent basis. The 

AHAM curves include material, labor, overhead, and depreciation and one-time 

expenses. 

For the 22 ft3 product 7 size, capital and one-time expenditure data was provided 

only for tooling/equipment costs. To assure that building, R&D, and marketing costs 

have been considered, the R&D and marketing costs for this product size have been set 

equal to the equivalent costs for the 26 ft3 product size. The building capital cost has been 

assumed to be proportional to tooling/equipment capital cost for product class 7. For 

product class 7, the DOE cost estimates are higher than the AHAM data at higher 

efficiency levels. However, the leveling off of the AHAM 25 ft3 curve is expected to be 

an anomaly of the reporting and aggregation process—this feature of the curve is not 

expected to be representative of the actual cost trend for this product. 

$300 

AHAM 25 cuft AVG
 

AHAM 22 cuft AVG
 

DOE 26 cuft
 

$250 DOE 22 cuft
 

DOE AVG
 

$200 t 

s 

o
 

l

C

at

n $150 e
 

m
 er

c 

nI

$100 

$50 

$-

Efficiency Level (%) 

Figure 5.9.6 Incremental Cost Curves for Product Class 7 

0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 

5-65
 

EERE-2008-BT-STD-0012 COMMENT 20
 

 

5.9.2.4 Product Class 9 

Incremental cost data for product class 9 refrigerator-freezers provided by AHAM 

is summarized in Table 5.9.5 below. 

Table 5.9.5 AHAM Incremental Cost Data for Product Class 9 

Efficiency Level 10% 20% 25% 30% 35% 

Product Class 9—14 ft3 

Incremental Cost Average 

(21%)* 

Material $10.86 $33.20 $21.92 $30.94 $40.86 

Labor $1.03 $3.79 $2.27 $3.07 $4.26 

Overhead $0.48 $1.28 $1.36 $1.45 $2.16 

CCE & OTPCE ($million) 

Total Industry 

Building CAPX 

(21%--3)* 

$0.1 $0.1 $3.2 $3.3 $3.5 

Tooling/Equipment 

CAPX (21%--3)* 

$0.2 $0.5 $5.6 $10.6 $15.9 

R&D (21%--3)* $0.3 $0.4 $2.8 $3.1 $3.2 

Marketing (21%--3)* $0.2 $0.2 $0.3 $0.3 $0.3 

ShipmentWeighted Average

Building CAPX $0 $0 $1.17 $1.17 $1.17 

Tooling/Equipment 

CAPX 

$0 $0 $1.95 $3.90 $5.88 

R&D $0 $0 $0.78 $0.79 $0.79 

Marketing $0 $0 $0 $0 $0 

Product Class 9—20 ft3 

Incremental Cost Average 

(21%)* 

Material $9.72 $32.90 $21.45 $31.55 $40.60 

Labor $0.78 $3.55 $2.40 $3.20 $4.21 

Overhead $0 $0.80 $1.50 $1.58 $1.98 

CCE & OTPCE ($million) 

Total Industry 

Building CAPX 

(21%--3)* 

$0 $0.2 $3.2 $3.4 $4.2 

Tooling/Equipment 

CAPX (21%--3)* 

$0 $0.5 $8.2 $15.7 $23.4 

R&D (21%--3)* $0 $0.3 $3.3 $3.7 $3.9 

Marketing (21%--3)* $0 $0.2 $0.3 $0.3 $0.3 

ShipmentWeighted Average

Building CAPX $0 $0 $1.17 $1.17 $1.18 

Tooling/Equipment 

CAPX 

$0 $0 $2.96 $5.84 $8.76 

R&D $0 $0 $1.17 $1.17 $1.17 

Marketing $0 $0 $0 $0 $0 

CCE&OTPCE: Conversion Capital Expenditures and One-Time Product Conversion Expenses. Material, 

Labor, and Overhead are per unit. Blank entries indicate that there were insufficient responses for AHAM 

to provide data. 

*Percent of the Product Class 9 shipments represented by these data and number of manufacturers 

represented (for capital and one-time expenditures). 

The AHAM incremental cost data for product class 9 are compared with the 

calculations carried out by DOE in Figure 5.9.7 below. The DOE costs in these curves 

have the manufacturer markup taken out so that they can be compared on a consistent 

basis. The AHAM curves include material, labor, overhead, and depreciation and one5-66 

EERE-2008-BT-STD-0012 COMMENT 20
 

time expenses. The DOE costs are lower than the AHAM data, especially at the 20% 

efficiency level, however the discrepancy diminishes at higher efficiency levels. 

$-

$25 

$50 

$75 

$100 

$125 

$150 

$175 

$200 

$225 

I

n 

c 

r

e 

m 

e 

n 

t

a 

l

C

o 

s 

t 

AHAM 14cuft AVG 

AHAM 20 cuft AVG 

DOE 14 cuft 

DOE 20 cuft 

DOE AVG 

0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 

Efficiency Level (%) 

Figure 5.9.7 Incremental Cost Curves for Product Class 9 

5-67
 

EERE-2008-BT-STD-0012 COMMENT 20
5.9.2.5 Product Class 11 

Incremental cost data for product class 11 (compact refrigerators and refrigeratorfreezers with manual defrost) provided by AHAM is summarized in Table 1 below. 

Table 5.9.6 AHAM Incremental Cost Data for Product Class 11 

Efficiency Level 10% 20% 25% 30% 35% 

Product Class 11—5.5 ft3 

Incremental 

Cost 

Average 

(54%)* 

Material $16.53 $71.17 $120.81 $130.12 $135.40 

Labor $0 $3.78 $7.55 $7.55 $7.55 

Overhea 

d 

$0 $0 $0 $0 $0 

CCE & OTPCE ($million) 

Total Industry 

Building CAPX Blank Blank Blank Blank Blank 

Tooling/Equipment 

CAPX (54%--3)* 

$0 $1.1 $1.1 $5.3 $5.5 

R&D Blank Blank Blank Blank Blank 

Marketing Blank Blank Blank Blank Blank 

ShipmentWeighted Average

Building CAPX Blank Blank Blank Blank Blank 

Tooling/Equipment 

CAPX 

$0 $0.41 $0.44 $2.04 $2.20 

R&D Blank Blank Blank Blank Blank 

Marketing Blank Blank Blank Blank Blank 

CCE&OTPCE: Conversion Capital Expenditures and One-Time Product Conversion Expenses. Material, 

Labor, and Overhead are per unit. Blank entries indicate that there were insufficient responses for AHAM 

to provide data. 

*Percent of the Product Class 11 shipments represented by these data and number of manufacturers 

represented (for capital and one-time expenditures). 

The AHAM incremental cost data for product class 11 are compared with the 

calculations carried out by DOE in Figure 5.9.8 below. The DOE costs in these curves 

have the manufacturer markup taken out so that they can be compared on a consistent 

basis. The AHAM curves include material, labor, overhead, and depreciation and onetime expenses. The discrepancy between the curves is very large. The high AHAM 

estimate for the 20% efficiency level is puzzling, because this is the ENERGY STAR 

level. DOE considers it unlikely that ENERGY STAR products of this product class 

could have $75 higher production cost than baseline efficiency products. Such products 

listed in the ENERGY STAR database are shown in Figure 5.9.9 below. The differences 

between the baseline and ENERGY STAR 4 ft3 refrigerators of the reverse engineering 

work include a larger evaporator, a different compressor, and slightly thicker walls, 

differences that would incur an order of magnitude less than $75 in additional production 

cost. The design option analysis uses a slightly different combination to achieve the 20% 

efficiency level: thicker wall, higher compressor efficiency, and a larger condenser. 

5-68
 

EERE-2008-BT-STD-0012 COMMENT 20
 

$-

$20 

$40 

$60 

$80 

$100 

$120 

$140 

$160 

$180 

$200 

I

n 

c 

r

e 

m 

e 

n 

t

a 

l

C

o 

s 

t 

AHAM 5.5 cuft AVG 

DOE 1.7 cuft 

DOE 4 cuft 

DOE AVG 

0% 5% 10% 15% 20% 25% 30% 35% 

Efficiency Level (%) 

Figure 5.9.8 Incremental Cost Curves for Product Class 11 Energy Use (kWh/year)

400 

350 

300 

250 

200 

150 

100 

50 

0 

DOE Standard 

Haier, Mircofridge Samsung, Haier 

Samsung 

GE Haier Samsung 

Microfridge 

Samsung Microfridge 

2 3 4 5 

Adjusted Volume (cuft) 

40% 45% 

6 7 

Figure 5.9.9 Product Class 11 Refrigerators listed in the ENERGY STAR Database 

5-69
 

EERE-2008-BT-STD-0012 COMMENT 20
 

 

REFERENCES 

1

 “ERA 1.2E, EPA Refrigerator Analysis Program, User’s Manual, Report to the 

Environmental Protection Agency Atmospheric Pollution Prevention Division,” Arthur 

D. Little, Inc., February 1997 

2

 "Engineering Computer Models for Refrigerators, Freezers, Furnaces, Water Heaters, 

Room and Central Air Conditioners," Report to U.S. DOE, by Arthur D. Little, Inc., 

November 1982. 

3

 McLinden, M., "Theoretical Vapor Compression Cycle, CYCLE7," unpublished. 

4

 Morrison, G., and McLinden, M., "Application of a Hard Sphere Equation of State to 

Refrigerants and Refrigerant Mixtures," National Bureau of Standards Technical Note 

1218, 1986. 

5

 "NIST Standard Reference Database 23: NIST Thermodynamic Properties of 

Refrigerants and Refrigerant Mixtures Database, Version 3.0," NIST, December 1991. 

6

 EPA Refrigerator Analysis (ERA) Program: User’s Manual, Version 1.0. United States 

Environmental Protection Agency. EPA-430-R-93-007. June 1993. with Version 1.2 

Update, November 1994. 

7

 M. T. Holtzapple and R. G. Carranza, “Heat Transfer and Pressure Drop of Spined Pipe 

in Cross-Flow – Part I: Pressure Drop Studies”, ASHRAE Transactions, 1990. 

8

 Holtzapple, M.T., A.L.Allen, and K.Lin, “Heat Transfer and Pressure Drop of Spined 

Pipe in Cross-Flow – Part II: Heat Transfer Studies, AHSRAE Transactions, 1990. 

9

 U.S. Department of Energy-Office of Codes and Standards. Technical Support 

Document: Energy Efficiency Standards for Consumer Products: Refrigerators, 

Refrigerator-Freezers, and Freezers, July 1995. Washington, DC. DOE/EE-0064. 

10 Va-q-plus data sheet, http://www.va-q-tec.com/produkte/en/pplus/prod/va-qplus_pdb_en.pdf 

5-70
 

EERE-2008-BT-STD-0012 COMMENT 20
 

11 “Electrolux's New Vacuum Insulated Freezer Technology,” Appliance Magazine, 

August 2003. 

<http://www.appliancemagazine.com/new_products.php?article=4971&zone=204&first=1> 

12 Personal communication with Embraco, March 2009. 

13 Energy Conservation Program for Consumer Products: Decision and Order Granting a 

Waiver to the General Electric Company From the Department of Energy Residential 

Refrigerator and Refrigerator-Freezer Test Procedure, Notice of decision and order, 

February 27, 2008. 73 FR 10425. 

14 http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=480-3168-2-ND 

5-71
 

EERE-2008-BT-STD-0012 COMMENT 20
APPENDIX 5-A. ENGINEERING DATA 
 

TABLE OF CONTENTS 

5-A.1 INTRODUCTION .................................................................................................5-A-1 

5-A.2 ERA INPUTS.........................................................................................................5-A-1 

5-A.3 INCREMENTAL COST DETAIL ......................................................................5-A-29 

5-A.4 ENGINEERING QUESTIONNAIRE .................................................................5-A-44 

LIST OF TABLES 

Table 5-A.2.1: ERA Inputs for Top-Mount Refrigerator-Freezers (Product Class 3) .........5-A-2 

Table 5-A.2.2: ERA Inputs for Bottom-Mount Refrigerator-Freezers (Product Class 5)....5-A-6 

Table 5-A.2.3: ERA Inputs for Bottom-Mount Refrigerator-Freezers w/TTD Ice 

(Product Class 5A).....................................................................................5-A-10 

Table 5-A.2.4: ERA Inputs for Side-Mount Refrigerator-Freezers (Product Classes 4 

and 7) .........................................................................................................5-A-14 

Table 5-A.2.5: ERA Inputs for Upright Freezers with Automatic Defrost (Product 

Class 9).......................................................................................................5-A-18 

Table 5-A.2.6: ERA Inputs for Chest Freezers with Manual Defrost (Product Class 10) .5-A-21 

Table 5-A.2.7: ERA Inputs for Compact Refrigerators (Product Class 11).......................5-A-23 

Table 5-A.2.8: ERA Inputs for Compact Chest Freezers (Product Class 18)....................5-A-26 

Table 5-A.3.1: Incremental Cost Detail for 16 ft3

 Top-Mount Refrigerator-Freezer 

(Product Class 3)........................................................................................5-A-30 

Table 5-A.3.2: Incremental Cost Detail for 21 ft3 Top-Mount Refrigerator-Freezer 

(Product Class 3)........................................................................................5-A-31 

Table 5-A.3.3: Incremental Cost Detail for 18.5 ft3 Bottom-Mount RefrigeratorFreezer (Product Class 5)...........................................................................5-A-32 

Table 5-A.3.4: Incremental Cost Detail for 25 ft3

 Bottom-Mount Refrigerator-Freezer 

(Product Class 5)........................................................................................5-A-33 

Table 5-A.3.5: Incremental Cost Detail for 22 ft3

 Side-Mount Refrigerator-Freezer with 

TTD Ice (Product Class 7) .........................................................................5-A-34 

Table 5-A.3.6: Incremental Cost Detail for 26 ft3

 Side-Mount Refrigerator-Freezer with 

TTD Ice (Product Class 7) .........................................................................5-A-35 

Table 5-A.3.7: Incremental Cost Detail for 14 ft3

 Upright Freezer with Auto Defrost 

(Product Class 9)........................................................................................5-A-36 

Table 5-A.3.8: Incremental Cost Detail for 20 ft3

 Upright Freezer with Auto Defrost 

(Product Class 9)........................................................................................5-A-37 

Table 5-A.3.9: Incremental Cost Detail for 15 ft3 Chest Freezer (Product Class 10)........5-A-38 

Table 5-A.3.10: Incremental Cost Detail for 20 ft3

 Chest Freezer (Product Class 10)........5-A-39 

Table 5-A.3.11: Incremental Cost Detail for 1.7 ft3 Compact Refrigerator (Product Class 

11) ..............................................................................................................5-A-40 

5-A-i 

EERE-2008-BT-STD-0012 COMMENT 20
Table 5-A.3.12: Incremental Cost Detail for 4.0 ft3

 Compact Refrigerator (Product Class 

11) ..............................................................................................................5-A-41 

Table 5-A.3.13: Incremental Cost Detail for 3.4 ft3

 Compact Chest Freezer (Product 

Class 18).....................................................................................................5-A-42 

Table 5-A.3.14: Incremental Cost Detail for 7.0 ft3 Compact Chest Freezer (Product 

Class 18).....................................................................................................5-A-43 

5-A-ii 

EERE-2008-BT-STD-0012 COMMENT 20
APPENDIX 5-A. ENGINEERING DATA 

5-A.1 INTRODUCTION 

The Energy-efficient Refrigerator Analysis Program (ERA) was used to calculate energy 

use for baseline and energy-saving configurations for the various product classes of refrigeration 

products. Inputs to this program were generated from reverse-engineering teardowns of select 

refrigerator and refrigerator-freezer models currently available. The values for the input variables 

are shown in tabular format in section 5-A.2. The input is provided to the extent possible in the 

format required for the Windows version of ERA. Because analysis was carried out with the 

DOE version of ERA for most of the products, in some cases the input format may not translate 

directly, and the output values may not match exactly. 

The incremental cost curves describing costs to attain each analyzed efficiency level are 

based on the energy use output from the ERA program. Development of costs for these curves is 

described in chapter 5. The tables in section 5-A.3 show these incremental cost curves in tabular 

format, with identification of the design options required to reach each efficiency level shown. 

As part of the engineering analysis, DOE solicited input from manufacturers on a range 

of technical topics affecting energy use in refrigeration products. The questionnaire used to 

facilitate these interviews is shown in section 5-A.4. 

5-A.2 ERA INPUTS 

The ERA inputs for each of the units selected for reverse-engineering analysis are shown 

below. Some general notes regarding the data include the following: 

1.	 Compressor compartment insulation thickness is specified directly in Windows ERA, 

while DOS ERA used bottom wall thickness. 

2.	 The ERA input for door openings is not provided, since DOE conducted analysis 

based on closed doors. 

3.	 Windows ERA includes separate input for the air in the compressor compartment. 

DOS ERA used the air temperature underneath the cabinet for this region. 

4.	 DOE conducted all analyses using single evaporator system configuration with HFC134a refrigerant. 

5.	 The tube and fin heat exchanger configuration implies forced convection air flow. 

6.	 See the Windows ERA program for definitions of air flow directions for forced 

convection wire fin condensers. 

5-A-1
 

EERE-2008-BT-STD-0012 COMMENT 20
 

7.	 Some products analyzed had spine fin evaporators, which are not supported by ERA. 

Input for a separate spine fin analysis spreadsheet calculation is provided in the tables 

below for these products. 

8.	 Windows ERA does not allow superheat or subcooling input of 0  ̊C, although DOS 

ERA does. Suggested input is 0.5  ̊C in cases where input of 0  ̊C is indicated. 

Table 5-A.2.1: ERA Inputs for Top-Mount Refrigerator-Freezers (Product Class 3) 

Top-Mount Refrigerator-Freezers 16 ft3 Baseline 21 ft3 Baseline 21 ft3 E* 

General Data 

Fresh Food Volume (ft3) 11.6 15.3 15.3 

Freezer Volume (ft3

) 4.1 5.3 5.3 

Total Volume (ft3) 15.7 20.6 20.6 

Adjusted Volume (ft3

) 18.3 23.9 23.9 

Rated Energy Use (kWh/yr) 455 509 408 

Calculated Max. Energy Use (kWh/yr) 455 511 511 

Rated Energy Use Below Maximum (%) 0.0 0.3 20.1 

Cabinet Dimensions 

Cabinet Height (cm) 146.7 165.6 165.6 

Cabinet Width (cm) 70.8 75.3 75.3 

Depth, from Door Flange (cm) 62.6 74.3 74.3 

Depth, from Door Outer Surface (cm) 71.1 80.7 80.7 

Liner Properties 

Outer Liner Thickness (mm) 0.4 0.4 0.4 

Outer Liner Conductivity (W/m-C) 44.7 44.7 44.7 

Inner Liner Thickness (mm) 1.0 1.5 2.0 

Liner Conductivity (W/m-C) 0.16 0.16 0.16 

Compressor Compartment Dimensions 

Top Depth (cm) 12.7 12.4 12.4 

Bottom Depth (cm) 21.6 25.8 25.8 

Height (cm) 26.0 16.0 16.0 

Wall (vertical) (cm) 4.3 5.1 5.1 

Wall (horizontal) (cm) 4.3 5.1 5.1 

Freezer Section 

 Insulation Thickness 

 Top Wall (cm) 5.3 7.1 7.1

 Side Wall (cm) 5.5 7.5 7.5

 Back Wall (cm) 7.0 7.9 7.9

 Door (cm) 6.2 7.2 7.2

 Insulation Resistivity 

 All Walls (m2-C/W-cm) 0.50 0.50 0.50

 Wedge/Flange Dimensions 

 Freezer Wedge Depth (cm) 7.6 7.0 7.0 

5-A-2
 

EERE-2008-BT-STD-0012 COMMENT 20
Top-Mount Refrigerator-Freezers 16 ft3

 Baseline 21 ft3 Baseline 21 ft3 E* 

 Freezer Flange Width (cm) 3.8 3.8 3.8

 Heat Paths 

 Freezer Gasket Heat Leak (W/m-100C) 9.0 9.0 9.0

 Fzr Cabinet Penetration Heat Leak (W) 1.5 0.0 0.0 

Fresh Food Section 

 Insulation Thickness 

 Side Wall (cm) 3.8 4.8 4.8

 Back Wall (cm) 5.0 4.9 4.9

 Bottom Wall (cm) 4.3 5.1 5.1

 Door (cm) 4.1 4.7 4.7

 Insulation Resistivity 

 All Walls (m2-C/W-cm) 0.50 0.50 0.50

 Wedge/Flange Dimensions 

 Fresh Food Wedge Depth (cm) 0.1 7.6 7.6

 Fresh Food Flange Width (cm) 3.8 3.8 3.8

 Heat Paths 

 FF Gasket Heat Leak (W/m-100C) 9.0 9.0 9.0

 FF Cabinet Penetration Heat Leak (W) 1.5 0.0 0.0 

Mullion 

 Distance to Top (cm) 44.5 50.8 50.8

 Thickness w/Liners (cm) 5.7 7.1 7.1

 Resistivity w/Liners (m2-C/W-cm) 0.5 0.5 0.5 

Air and Cabinet Temperatures 

 Room Air (°C) 32.2 32.2 32.2

 Freezer Section (°C) -15 -15 -15

 Fresh Food Section (°C) 7.2 7.2 7.2

 Air Under Cabinet (°C) 35.0 35.0 35.0

 Compressor Compartment ( ̊C) 35.0 35.0 35.0

 Air Entering Condenser (°C) 32.2 33.0 33.0 

Defrost and Controls Energy 

Defrost Type (Automatic, Manual) Automatic Automatic Automatic

 Timer Interval (Hr) 14.0 10.5 10.5

 Heater On-Time (Min) 8.0 4.8 4.8

 Defrost Power (W) 390 413 413 

Other Cycle-Dependent Loads 

 Freezer Section (W) 0 0 0

 Fresh Food Section (W) 0.3 0.3 0.3

 Outside Cabinet (W) 0 0 0 

Constant Electrical Loads 

 Freezer Section (W) 0 0 0

 Fresh Food Section (W) 0 0 0

 Outside Cabinet (W) 0 0 0 

Liquid Refrigerant Line Anti-Sweat 

5-A-3
 

EERE-2008-BT-STD-0012 COMMENT 20
 

Top-Mount Refrigerator-Freezers 16 ft3 Baseline 21 ft3 Baseline 21 ft3 E* 

Freezer Door Flange 

 Cycle Average Energy (W) 4 3.8 3.8

 Fraction Heat Leak (0-1) 0.5 0.3 0.3 

Fresh Food Door Flange 

 Cycle Average Energy (W) 0 0 0

 Fraction Heat Leak (0-1) 0 0 0 

Mullion 

 Cycle Average Energy (W) 1.5 1.3 1.3

 Heat Leak to Freezer (0-1) 0.25 0.25 0.25

 Heat Leak to Fresh Food (0-1) 0.25 0.25 0.25 

Evaporator Design 

Exit Superheat 2 2 0

 Fin Type (flat, wavy, herringbone) Spine Flat Flat

 Fan Motor Type AC-Input 

BLDC Shaded Pole Shaded Pole

 Fan Power (W) 3.5 6.1 5.7

 Air Flow Rate (Liter/s) 16.6 21.3 21.3 

Tube Characteristics 

 Width of Tube Row 52.1 45.7 45.7

 Tube OD (mm) 9.4 7.9 7.9

 Tube Wall Thickness (mm) 0.76 0.6 0.6

 # of Tubes Deep 7 4 4

 Tube Pitch (cm) 2.5 3.8 3.8

 # of Tubes Normal to Airflow 2 6 6

 Normal Tube Pitch (cm) 2.5 1.9 1.9 

Fin Characteristics 

 Fin Thickness (mm) 0.25 0.13 0.13

 Fin Pitch (mm) 9.5 6.3 6.3

 Fin Conductivity (W/m-K) 190 190 190

 Fraction Finned (0-1) 0.93 0.89 0.89 

Spine Fin Input Data 

 Spine Height (mm) 10.5 NA NA

 Spine Width (mm) 0.79 NA NA 

Condenser Design a a 

Exit Subcooling (°C) 2 0 0

 Configuration (Static, Hot-wall, Tube 

& Fin, Microchannel) Tube & Fin Tube & Fin Tube & Fin

 Air-side Configuration (wire, plain, 

smooth wavy, herringbone, slit, louver) Wire Wire Wire 

a

 Surface areas calculated by the condenser routine were increased by a factor of 2.56 for the 21 ft3 top-mount 

refrigerators to calibrate with test data for condensing temperatures. 

5-A-4 

EERE-2008-BT-STD-0012 COMMENT 20
Top-Mount Refrigerator-Freezers 16 ft3

 Baseline 21 ft3 Baseline 21 ft3 E* 

Fan Motor Type Shaded Pole Shaded Pole AC-input 

BLDC

 Fan Power (W) 11.2 9.4 3.3

 Air Flow Rate (Liter/s) 30.0 26.0 31.2 

Tube Characteristics 

Airflow Direction (W, L, H) W W W

 Tube OD (mm) 4.8 4.8 4.8

 Tube Wall Thickness (mm) 0.8 0.6 0.6

 Length of Tube in “L” Direction 59.6 20.1 20.1

 # of Tubes in H Direction 1 8 8

 Tube Pitch (cm) 2.5 2.5 2.5

 # of Tubes in W Direction 14 6 6

 Tube Pitch (cm) 2.5 2.5 2.5

 Fraction Air through Exchanger (0-1) 0.6 0.9 0.9 

Fin Characteristics 

 Wire OD (mm) 1.5 1.1 1.1

 # of Wires on 1-side per layer 95 29 29

 Wire Mounting (1-side, 2-sides) 2-sides 2-sides 2-sides

 Wire Fin Pitch (mm) 5.1 5.1 5.1

 Wire Length (cm) 34.9 14.0 14.0

 Wire Conductivity (W/m-K) 44.7 44.7 44.7 

Compressor Data 

Manufacturer Matsushita Matsushita Matsushita

 Model # DGS57C84RAU SF51C97RAU6 DHS57C85RAU 

Cycles per hour 1.0 1.0 1.0 

Interchanger 

Effectiveness (0-1) 0.9 0.95 0.95 

5-A-5
 

EERE-2008-BT-STD-0012 COMMENT 20
Table 5-A.2.2: ERA Inputs for Bottom-Mount Refrigerator-Freezers (Product Class 5) 

Bottom-Mount Refrigerator-Freezers 18.5 ft3 25 ft3

 E*, #1 25 ft3 E*, #2 

General Data 

 Fresh Food Volume (ft3

) 13.1 17.8 17.6

 Freezer Volume (ft3

) 5.4 7.3 7.7

 Total Volume (ft3) 18.5 25.1 25.3

 Adjusted Volume (ft3) 21.9 29.6 30.2

 Rated Energy Use (kWh/yr) 476 475 478

 Calculated Max. Energy Use (kWh/yr) 560 595 598

 Rated Energy Use Below Maximum (%) 15.0 20.2 20.0 

Cabinet Dimensions 

Cabinet Height (cm) 160.7 168.3 168.0 

Cabinet Width (cm) 75.3 90.5 90.8 

Depth, from Door Flange (cm) 69.2 72.4 71.3 

Depth, from Door Outer Surface (cm) 76.8 79.4 78.3 

Liner Properties 

Outer Liner Thickness (mm) 0.5 0.6 0.5 

Outer Liner Conductivity (W/m-C) 44.7 43.3 44.7 

Inner Liner Thickness (mm) 1.3 1.9 1.4 

Liner Conductivity (W/m-C) 0.16 0.16 0.16 

Compressor Compartment Dimensions 

Top Depth (cm) 16.5 17.1 12.7 

Bottom Depth (cm) 27.0 27.3 25.4 

Height (cm) 24.5 24.1 22.9 

Wall (vertical) (cm) 7.0 6.9 6.6 

Wall (horizontal) (cm) 7.0 6.9 6.6 

Freezer Cabinet 

 Insulation Thickness 

 Side Wall (cm) 6.9 7.5 6.8

 Back Wall (cm) 7.9 6.5 7.6

 Bottom (cm) 7.0 6.9 6.6

 Door (cm) 6.3 6.0 6.9

 Insulation Resistivity 

 All Walls (m2-C/W-cm) 0.50 0.50 0.53

 Wedge/Flange Dimensions 

 Freezer Wedge Depth (cm) 5.1 6.4 5.1

 Freezer Flange Width (cm) 3.8 3.8 5.4

 Heat Paths 

 Freezer Gasket Heat Leak (W/m-100C) 9.5 8.0 8.0

 Fzr Cabinet Penetration Heat Leak (W) 0 3 0 

Fresh Food Cabinet 

 Insulation Thickness 

 Top Wall (cm) 5.2 3.9 4.2

 Side Wall (cm) 4.2 5.1 3.5 

5-A-6
 

EERE-2008-BT-STD-0012 COMMENT 20
Bottom-Mount Refrigerator-Freezers 18.5 ft3 25 ft3

 E*, #1 25 ft3 E*, #2

 Back Wall (cm) 5.7 6.8 4.1

 Door (cm) 4.3 4.9 6.9

 Insulation Resistivity 

 All Walls (m2-C/W-cm) 0.50 0.50 0.53

 Wedge/Flange Dimensions 

 Fresh Food Wedge Depth (cm) 10.2 11.4 0.0

 Fresh Food Flange Width (cm) 3.8 3.8 3.4

 Heat Paths 

 FF Gasket Heat Leak (W/m-100C) 9.5 8.0 8.0

 FF Cabinet Penetration Heat Leak (W) 0.0 3.0 0.0 

Mullion 

 Distance to Top (cm) 92.7 100.0 94.3

 Thickness w/Liners (cm) 5.4 5.4 7.3

 Resistivity w/Liners (m2-C/W-cm) 0.50 0.51 0.5 

Air and Cabinet Temperatures 

 Room Air (°C) 32.2 32.2 32.2

 Freezer Section (°C) -15.0 -15.0 -15.0

 Fresh Food Section (°C) 7.2 7.2 7.2

 Air Under Cabinet (°C) 36.6 35.0 35.0

 Compressor Compartment ( ̊C) 36.6 35.0 35.0

 Air Entering Condenser (°C) 32.2 33.0 34.5 

Defrost and Controls Energy 

Defrost Type (Automatic, Manual) Automatic Automatic Automatic

 Timer Interval (Hr) 7.5 38.0 38.0

 Heater On-Time (Min) 7.0 7.0 24.0

 Defrost Power (W) 375 450 440 

Other Cycle-Dependent Loads 

 Freezer Section (W) 0 0 0

 Fresh Food Section (W) 3 0 0

 Outside Cabinet (W) 0 0 0 

Constant Electrical Loads 

 Freezer Section (W) 0.7 0.0 4.2

 Fresh Food Section (W) 0.0 0.4 0.0

 Outside Cabinet (W) 0.0 0.0 1.5 

Liquid Refrigerant Line Anti-Sweat 

Freezer Door Flange 

 Cycle Average Energy (W) 1.0 3.8 3.0

 Fraction Heat Leak (0-1) 0.75 0.5 0.75 

Fresh Food Door Flange 

 Cycle Average Energy (W) 0 0 0 

Mullion 

 Cycle Average Energy (W) 2 1.3 1.0

 Heat Leak to Freezer (0-1) 0.75 0.5 0.5 

5-A-7
 

EERE-2008-BT-STD-0012 COMMENT 20
 

Bottom-Mount Refrigerator-Freezers 18.5 ft3 25 ft3 E*, #1 25 ft3 E*, #2

 Heat Leak to Fresh Food (0-1) 0.15 0.25 0.25 

Evaporator Design 

Exit Superheat (°C) 0.8 4.0 1.0

 Fin Type (flat, wavy, herringbone) Flat Flat Spine Fin

 Fan Motor Type (Shaded Pole, AC-Input 

BLDC, DC-Input BLDC) Shaded Pole Shaded Pole DC-Input BLDC

 Fan Power (W) 6.2 6.5 3.8

 Air Flow Rate (Liter/s) 20 30 16.6 

Tube Characteristics 

 Width of Tube Row 48.9b 71.1c

 76.2

 Tube OD (mm) 7.9 7.9 9.7

 Tube Wall Thickness (mm) 0.5 0.5 1.1

 # of Tubes Deep 4.5b 4.5c 7

 Tube Pitch (cm) 3.8 3.6 2.5

 # of Tubes Normal to Airflow 4 4 2

 Normal Tube Pitch (cm) 1.9 1.9 2.5 

Fin Characteristics 

 Fin Thickness (mm) 0.13 0.13 0.25

 Fin Pitch (mm) 5.1 5.1 9.5

 Fin Conductivity (W/m-K) 190 190 190

 Fraction Finned (0-1) 0.98 0.89 1.0 

Spine Fin Input Data 

 Spine Height (mm) NA NA 10.5

 Spine Width (mm) NA NA 0.8 

Condenser Design 

Exit Subcooling (°C) 0.7 1.0 1.5

 Configuration (Static, Hot-wall, Tube & 

Fin, Microchannel) Tube & Fin Tube & Fin Tube & Fin

 Air-side Configuration (wire, plain, 

smooth wavy, herringbone, slit, louver) Wire Wire Wire

 Fan Motor Type (Shaded Pole, AC-Input 

BLDC, DC-Input BLDC) 

AC-Input 

BLDC 

AC-Input 

BLDC 

DC-Input 

BLDC

 Fan Power (W) 3.8 3.7 2.6

 Air Flow Rate (Liter/s) 30 30.8 23.7 

Tube Characteristics 

Airflow Direction (W, L, H) L L H

 Tube OD (mm) 4.8 4.8 5.0

 Tube Wall Thickness (mm) 0.5 0.6 0.64 

b

 Number of tubes in the air flow direction alternate 4 and 5, averaging 4.5. ERA analysis was conducted by 

selecting 4 rows deep and increasing the tube row width to 55.0 cm to compensate for the missing tubes. 

c

 Number of tubes in the air flow direction alternate 4 and 5, averaging 4.5. ERA analysis was conducted by 

selecting 4 rows deep and increasing the tube row width to 80.0 cm to compensate for the missing tubes. 

5-A-8 

EERE-2008-BT-STD-0012 COMMENT 20
Bottom-Mount Refrigerator-Freezers 18.5 ft3 25 ft3

 E*, #1 25 ft3 E*, #2

 Length of Tube in “L” Direction (cm) 34.9 34.9 52.4

 # of Tubes in H Direction 2 2 3

 Tube Pitch (cm) 2.2 3.8 0.8

 # of Tubes in W Direction 26 30 10

 Tube Pitch (cm) 2.2 2.2 2.5

 Fraction Air through Exchanger (0-1) 0.8 1.0 1 

Fin Characteristics 

 Wire OD (mm) 1.3 1.3 1.4

 # of Wires on 1-side 55 51 206

 Wire Mounting (1-side, 2-sides) 2-sides 2-sides 2-sides

 Wire Fin Pitch (mm) 4.8 4.8 2.5

 Wire Length (cm) 57.1 66.7 23.5

 Wire Conductivity (W/m-K) 44.7 44.7 44.7 

Compressor Data 

Manufacturer Embraco Tecumseh Embraco

 Model EMX70HSC TPG1370YXA VEGY 8H

 Cycles per hour 1.0 1.5 0.45 

Interchanger 

Effectiveness (0-1) NA 0.95 0.98

 Compressor Shell Inlet Temperature (°C) 33.3 Unspecified Unspecified 

5-A-9
 

EERE-2008-BT-STD-0012 COMMENT 20
 

Table 5-A.2.3: ERA Inputs for Bottom-Mount Refrigerator-Freezers w/TTD Ice (Product 

Class 5A) 

Bottom-Mount Refrigerator-Freezers w/TTD Ice 

General Data 

25 ft3 

 Fresh Food Volume (ft3) 17.6

 Freezer Volume (ft3) 7.1

 Total Volume (ft3) 24.7

 Adjusted Volume (ft3

) 29.2

 Rated Energy Use (kWh/yr) 547

 Calculated Max. Energy Use (kWh/yr) 685

 % Rated Energy Use Below Maximum (%) 20.0 

Cabinet Dimensions 

Cabinet Height (cm) 171.1 

Cabinet Width (cm) 91.4 

Depth, from Door Flange (cm) 68.6 

Depth, from Door Outer Surface (cm) 76.2 

Liner Properties 

Outer Liner Thickness (mm) 0.5 

Outer Liner Conductivity (W/m-C) 44.7 

Inner Liner Thickness (mm) 1.4 

Liner Conductivity (W/m-C) 0.16 

Compressor Compartment Dimensions 

Top Depth (cm) 13.5 

Bottom Depth (cm) 26.7 

Height (cm) 24.5 

Wall (vertical) (cm) 6.8 

Wall (horizontal) (cm) 6.8 

Freezer Cabinet 

 Insulation Thickness 

 Side Wall (cm) 6.8

 Back Wall (cm) 7.9

 Bottom (cm) 6.8

 Door (cm) 7.1

 Insulation Resistivity 

 All Walls (m2-C/W-cm) 0.48d

 Wedge/Flange Dimensions 

 Freezer Wedge Depth (cm) 2.5

 Freezer Flange Width (cm) 4.5

 Heat Paths 

 Freezer Gasket Heat Leak (W/m-100C) 8e 

d

 Product has insulation using cyclopentane blowing agent. 

e

 The heat leak parameter entered into ERA was increased to 12.63 to account for additional gasket length, since the 

freezer compartment of this product has two drawers. 

5-A-10 

EERE-2008-BT-STD-0012 COMMENT 20
 

Bottom-Mount Refrigerator-Freezers w/TTD Ice 25 ft3

 Freezer Cabinet Penetration Heat Leak (W) 0 

Fresh Food Cabinet 

 Insulation Thickness 

 Top Wall (cm) 5.2

 Side Wall (cm) 5.1

 Back Wall (cm) 4.7

 Door (cm) 5.1

 Insulation Resistivity 

 All Walls (m2-C/W-cm) 0.48

 Wedge/Flange Dimensions 

 Fresh Food Wedge Depth (cm) 11.4

 Fresh Food Flange Width (cm) 4.8

 Heat Paths 

 Fresh Food Gasket Heat Leak (W/m-100C) 8f

 Fresh Food Cabinet Penetration Heat Leak (W) 3.0 

Mullion 

 Distance to Top (cm) 102.2

 Thickness w/Liners (cm) 5.1

 Resistivity w/Liners (m2-C/W-cm) 0.47 

Air and Cabinet Temperatures 

 Room Air (°C) 32.2

 Freezer Section (°C) -15.0

 Fresh Food Section (°C) 7.2

 Air Under Cabinet (°C) 35.0

 Compressor Compartment ( ̊C) 35.0

 Air Entering Condenser (°C) 32.2 

Defrost and Controls Energy 

Defrost Type (Automatic, Manual) Automatic

 Timer Interval (Hr) 38.0

 Heater On-Time (Min) 12.7

 Defrost Power (W) 396 

Other Cycle-Dependent Loads 

 Freezer Section (W) 0

 Fresh Food Section (W) 0

 Outside Cabinet (W) 0 

Constant Electrical Loads 

 Freezer Section (W) 0

 Fresh Food Section (W) 0

 Outside Cabinet (W) 4.0 

Liquid Refrigerant Line Anti-Sweat 

f

 The heat leak parameter entered into ERA was increased to 12.3 to account for additional gasket length, since the 

fresh food compartment of this product has French doors. 

5-A-11 

EERE-2008-BT-STD-0012 COMMENT 20
 

 

Bottom-Mount Refrigerator-Freezers w/TTD Ice 25 ft3 

Freezer Door Flange 

 Cycle Average Energy (W) 3.8

 Fraction Heat Leak (0-1) 0.5 

Fresh Food Door Flange 

 Cycle Average Energy (W) 0

 Fraction Heat Leak (0-1) 0 

Mullion 

 Cycle Average Energy (W) 1.3

 Heat Leak to Freezer (0-1) .5

 Heat Leak to Fresh Food (0-1) .25 

Evaporator Design 

Exit Superheat (°C) 0.8

 Fin Type (flat, wavy, herringbone) Flat

 Fan Motor Type (Shaded Pole, AC-Input BLDC, DC-Input BLDC) DC-Input BLDC

 Fan Power (W) 1.5

 Air Flow Rate (Liter/s) 16.0 

Tube Characteristics 

 Width of Tube Row 70.5g

 Tube OD (mm) 7.9

 Tube Wall Thickness (mm) 0.7

 # of Tubes Deep 4.5g

 Tube Pitch (cm) 3.8

 # of Tubes Normal to Airflow 4

 Normal Tube Pitch (cm) 2.5 

Fin Characteristics 

 Fin Thickness (mm) 0.15

 Fin Pitch (mm) 5.1

 Fin Conductivity (W/m-K) 190

 Fraction Finned (0-1) 0.90 

Condenser Design 

Exit Subcooling (°C) 0.7

 Configuration (Static, Hot-wall, Tube & Fin, Microchannel) Tube & Fin

 Air-side Configuration (wire, plain, smooth wavy, herringbone, slit, 

louver) Wire

 Fan Motor Type (Shaded Pole, AC-Input BLDC, DC-Input BLDC) DC-Input BLDC

 Fan Power (W) 1.6

 Air Flow Rate (Liter/s) 24.0 

Tube Characteristics 

Airflow Direction (W, L, H) W

 Tube OD (mm) 5.0 

g

 Number of tubes in the air flow direction alternate 4 and 5, averaging 4.5. ERA analysis was conducted by 

selecting 4 rows deep and increasing the tube row width to 79.3 cm to compensate for the missing tubes. 

5-A-12 

EERE-2008-BT-STD-0012 COMMENT 20
0.64

15.2

12

2.2

10

2.5

0.9 

Bottom-Mount Refrigerator-Freezers w/TTD Ice 25 ft3

 Tube Wall Thickness (mm)
 

 Length of Tube in “L” Direction (cm)
 

# of Tubes in H Direction 

 Tube Pitch (cm) 

 # of Tubes in W Direction 

 Tube Pitch (cm) 

Fraction Air through Exchanger (0-1) 

Fin Characteristics 

 Wire OD (mm) 

 # of Wires on 1-side 

 Wire Mounting (1-side, 2-sides) 

 Wire Fin Pitch (mm)
 

 Wire Length (cm)
 

 Wire Conductivity (W/m-K) 

Compressor Data 

Manufacturer 

Model # 

Cycles per Hour 

Interchanger 

Effectiveness (0-1) 

1.4

22

2-sides

6.4

18.0

44.7
 

Embraco

EGX90HLC

1.0
 

5-A-13
 

0.95 

EERE-2008-BT-STD-0012 COMMENT 20
Table 5-A.2.4: ERA Inputs for Side-Mount Refrigerator-Freezers (Product Classes 4 and 

7) 

Side-Mount Refrigerator-Freezers PC7 26 ft3 PC7 26 ft3

 E* PC4 22 ft3 

General Data 

 Fresh Food Volume (ft3) 16.5 16.5 14.8

 Freezer Volume (ft3

) 9.5 9.5 7.0

 Total Volume (ft3) 26.0 26.0 

 Adjusted Volume (ft3) 32.0 32.0 26.3

 Rated Energy Use (ft3

) 728 582 635

 Calculated Max. Energy Use (kWh/yr) 729 729 637

 % Rated Energy Use Below Maximum 

(%) 0.2 20.2 0.3 

Cabinet Dimensions 

Cabinet Height (cm) 165.9 165.9 162.6 

Cabinet Width (cm) 90.2 90.2 85.1 

Depth, from Door Flange (cm) 72.0 72.0 69.3 

Depth, from Door Outer Surface (cm) 80.3 80.3 77.8 

Liner Properties 

Outer Shell Thickness (mm) 0.5 1 0.4 

Shell Conductivity (W/m-C) 44.7 44.7 44.7 

Inner Liner Thickness (mm) 0.5 1 0.4 

Liner Conductivity (W/m-C) 0.16 0.16 44.7 

Compressor Compartment Dimensions 

Top Depth (cm) 15.9 15.9 24.1 

Bottom Depth (cm) 27.9 27.9 30.5 

Height (cm) 23.5 23.5 25.1 

Wall (vertical) (cm) 8.3 8.3 5.8 

Wall (horizontal) (cm) 8.3 8.3 5.8 

Freezer Cabinet 

 Insulation Thickness – Freezer 

 Top Wall (cm) 7.2 7.2 6.2

 Side Wall (cm) 5.7 5.7 7.3

 Back Wall (cm) 7.8 7.8 5.7

 Bottom (cm) 8.3 8.3 5.8

 Door (cm) 6.4 6.4 5.7 

Insulation Resistivity - Freezer 

 All Walls (m2-C/W-cm) 0.50 0.50 0.5 

Wedge/Flange Dimensions 

 Freezer Wedge Depth (cm) 0.1 0.1 7.0

 Freezer Flange Width (cm) 5.7 5.7 3.8

 Heat Paths 

 Fzr Gasket Heat Leak (W/m-100C) 9.0 9.0 9.0

 Fzr Cabinet Penetration Heat Leak (W) 11.0 11.0 8.0 

Fresh Food Cabinet 

5-A-14
 

EERE-2008-BT-STD-0012 COMMENT 20
Side-Mount Refrigerator-Freezers PC7 26 ft3 PC7 26 ft3

 E* PC4 22 ft3

 Insulation Thickness – Fresh Food 

 Top Wall (cm) 4.0 4.0 4.0

 Side Wall (cm) 3.6 3.6 3.8

 Back Wall (cm) 3.6 3.6 4.8

 Bottom (cm) 6.2 6.2 4.7

 Door (cm) 6.4 6.4 5.7

 Insulation Resistivity – Fresh Food 

 All Walls (m2-C/W-cm) 0.50 0.50 0.5

 Wedge/Flange Dimensions 

 Fresh Food Wedge Depth (cm) 0.1 0.1 11.4

 Fresh Food Flange Width (cm) 3.6 3.6 3.8

 Heat Paths 

 FF Gasket Heat Leak (W/m-100C) 9.0 9.0 9.0

 FF Cabinet Penetration Heat Leak (W) 8.0 8.0 5.0

 Mullion 

 Distance to Right Side Wall (cm) 49.2 49.2 49.4

 Thickness w/Liners (cm) 3.5 3.5 3.7

 Resistivity w/Liners (m2-C/W-cm) 0.53 0.53 0.52 

Air and Cabinet Temperatures 

 Room Air (°C) 32.3 32.2 32.3

 Freezer Section (°C) -15.0 -15.0 -15.0

 Fresh Food Section (°C) 7.2 7.2 7.2

 Air Under Cabinet (°C) 35.0 35.0 35.0

 Compressor Compartment ( ̊C) 35.0 35.0 35.0

 Air Entering Condenser (°C) 33.0 33.0 33.0 

Defrost and Controls Energy 

Defrost Type (Automatic, Manual) Automatic Automatic Automatic

 Timer Interval (Hr) 10.0 10.0 38.0

 Heater On-Time (Min) 5.0 5.0 18.0

 Defrost Power (W) 500 500 535 

Other Cycle-Dependent Loads 

 Freezer Section (W) 0 0 0

 Fresh Food Section (W) 0 0 0

 Outside Cabinet (W) 0 0 0 

Constant Electrical Loads 

 Freezer Section (W) 0 0 0

 Fresh Food Section (W) 0.5 0.4 0

 Outside Cabinet (W) 0 0 1.3 

Electric Anti-Sweat Heat 

Freezer Door Flange 

 Cycle Average Energy (W) 2.1 2.1 0

 Fraction Heat Leak (0-1) 0.5 0.5 0.5 

Liquid Refrigerant Line Anti-Sweat 

5-A-15
 

EERE-2008-BT-STD-0012 COMMENT 20
 

Side-Mount Refrigerator-Freezers PC7 26 ft3 PC7 26 ft3 E* PC4 22 ft3 

Freezer Door Flange 

 Cycle Average Energy (W) 3.0 3.0 3.8

 Fraction Heat Leak (0-1) 0.5 0.5 0.5 

Fresh Food Door Flange 

 Cycle Average Energy (W) 0 0 0

 Fraction Heat Leak (0-1) 0 0 0 

Mullion 

 Cycle Average Energy (W) 3.0 3.0 1.3

 Heat Leak to Freezer (0-1) 0.5 0.5 0.25

 Heat Leak to Fresh Food (0-1) 0.25 0.25 0.25 

Evaporator Design 

Exit Superheat (°C) 4.0 4.0 2.0

 Fin Type (flat, wavy, herringbone) Flat Flat Spine Fin

 Fan Motor Type (Shaded Pole, ACInput BLDC, DC-Input BLDC) Shaded Pole Shaded Pole DC-Input BLDC

 Fan Power (W) 5.8 5.8 3.3

 Air Flow Rate (Liter/s) 21.3 21.3 21.3 

Tube Characteristics 

 Width of Tube Row 27.9h 27.9h 24.1

 Tube OD (mm) 7.9 7.9 9.3

 Tube Wall Thickness (mm) 0.7 0.7 0.8

 # of Tubes Deep 7.5h 7.5h

 16

 Tube Pitch (cm) 3.8 3.8 2.9

 # of Tubes Normal to Airflow 8 8 2

 Normal Tube Pitch (cm) 1.3 1.3 5.1 

Fin Characteristics 

 Fin Thickness (mm) 0.2 0.2 0.25

 Fin Pitch (mm) 5.1 5.1 9.5

 Fin Conductivity (W/m-K) 190 190 190

 Fraction Finned (0-1) 0.77 0.77 1 

Spine Fin Input Data 

 Spine Height (mm) NA NA 10.5

 Spine Width (mm) NA NA 0.8 

Condenser Design i i j

 Exit Subcooling (°C) 0.0 0.0 0.0

 Configuration (Static, Hot-wall, Tube & Tube & Fin Tube & Fin Tube & Fin 

h

 Number of tubes in the air flow direction alternate 7 and 8, averaging 7.5. ERA analysis was conducted by 

selecting 8 rows deep and decreasing the tube row width to 26.2 cm to compensate for the added tubes. 

i

 Surface areas calculated by the condenser routine were increased by a factor of 2.63 for the 26 ft3 side-mount 

refrigerators to calibrate with test data for condensing temperatures. 

j

 Surface area calculated by the condenser routine was increased by a factor of 1.4 for the 22 ft3 side-mount 

refrigerator to calibrate with test data for condensing temperatures. 

5-A-16 

EERE-2008-BT-STD-0012 COMMENT 20