5-i

CHAPTER 5. ENGINEERING ANALYSIS 

TABLE OF CONTENTS 

5.1 INTRODUCTION ........................................................................................................... 5-1 

5.2 EQUIPMENT CLASSES ANALYZED.......................................................................... 5-1 

5.3 METHODOLOGY OVERVIEW .................................................................................... 5-4 

5.4 COST MODEL ................................................................................................................ 5-6 

5.4.1 Manufacturer Production Cost Estimates and Assumptions................................ 5-6 

5.4.2 Structure of the Cost Model Spreadsheet............................................................. 5-8 

5.4.3 Material Prices ..................................................................................................... 5-9 

5.4.4 Results.................................................................................................................. 5-9 

5.5 MANUFACTURER MARKUP AND LIST PRICE MARKUP................................... 5-13 

5.6 ENERGY CONSUMPTION MODEL .......................................................................... 5-14 

5.6.1 Screened-In Technologies.................................................................................. 5-14 

5.6.2 Screened-In Technologies Not Considered in the Engineering Analysis.......... 5-15 

5.6.2.1 Remote Lighting Ballast Location......................................................... 5-15 

5.6.2.2 Evaporator Fan Motor Controllers......................................................... 5-15 

5.6.2.3 Higher Efficiency Evaporator and Condenser Fan Blades .................... 5-16 

5.6.2.4 Improved Insulation............................................................................... 5-16 

5.6.2.5 Low-Pressure Differential Evaporators ................................................. 5-17 

5.6.2.6 Defrost Cycle Control............................................................................ 5-17 

5.6.2.7 Defrost Mechanisms .............................................................................. 5-17 

5.6.3 Design Options................................................................................................... 5-17 

5.6.3.1 Higher Efficiency Lighting and Ballasts................................................ 5-18 

5.6.3.2 Higher Efficiency Evaporator Fan Motors ............................................ 5-20 

5.6.3.3 Increased Evaporator Surface Area ....................................................... 5-21 

5.6.3.4 Increased Insulation Thickness.............................................................. 5-22 

5.6.3.5 Improved Doors ..................................................................................... 5-23 

5.6.3.6 Higher Efficiency Condenser Fan Motors ............................................. 5-25 

5.6.3.7 Increased Condenser Surface Area ........................................................ 5-25 

5.6.3.8 Higher Efficiency Compressors............................................................. 5-26 

5.6.4 Baseline Specifications ...................................................................................... 5-27 

5.6.5 Non-Numerical Assumptions............................................................................. 5-28 

5.6.6 Numerical Constants and Assumptions ............................................................. 5-29 

5.6.7 Model Components............................................................................................ 5-30 

5.6.7.1 Component Energy Consumption.......................................................... 5-31 

5.6.7.2 Compressor Energy Consumption ......................................................... 5-32 

5.6.7.3 Component Load Model ........................................................................ 5-33 

5.6.7.4 Radiation Load Model ........................................................................... 5-34 

5.6.7.5 Conduction Load Model ........................................................................ 5-35 

5.6.7.6 Infiltration Load Model.......................................................................... 5-36 

5.7 COST-EFFICIENCY CURVES .................................................................................... 5-37 

5.8 OFFSET FACTORS ...................................................................................................... 5-54 

5.9 EXTENSION OF STANDARDS.................................................................................. 5-56 

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5-ii

5.9.1 Extension Multipliers......................................................................................... 5-57 

5.10 SENSITIVITY ANALYSES ......................................................................................... 5-60 

5.10.1 Material Price Sensitivity................................................................................... 5-60 

5.10.2 Alternative Refrigerants..................................................................................... 5-61 

5.11 RESULTS ...................................................................................................................... 5-62 

REFERENCES .......................................................................................................................... 5-63 

LIST OF TABLES 

Table 5.2.1 Shipment Data and Equipment Classes Analyzed.................................................. 5-3 

Table 5.2.2 Equipment Classes Analyzed in the Engineering Analysis.................................... 5-4 

Table 5.4.1 Major Manufacturing Processes ............................................................................. 5-9 

Table 5.4.2 Extension of Cost Model Estimates to Other Equipment Classes........................ 5-13 

Table 5.6.1 Details for Lighting for VOP, SVO, HZO, and SOC Equipment Families Design 

Option ................................................................................................................... 5-20 

Table 5.6.2 Details for Lighting for VCT Equipment Family Design Option......................... 5-20 

Table 5.6.3 Details for Evaporator Fan Motor Design Option ................................................ 5-21 

Table 5.6.4 Details for Evaporator Coil Design Option .......................................................... 5-21 

Table 5.6.5 Properties of Standard and Enhanced Evaporator Coil ........................................ 5-22 

Table 5.6.6 Insulation Thickness Increase Assumptions......................................................... 5-23 

Table 5.6.7 Details for Doors for VCT Equipment Family, Low Temperature Design Option.. 5-

24 

Table 5.6.8 Details for Doors for VCT Equipment Family, Medium Temperature Design Option

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

Table 5.6.9 Details for “Doors for HCT Equipment Family, Ice-Cream Temperature” Design 

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

Table 5.6.10 Details for Doors for SOC Equipment Family, Medium Temperature Design 

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

Table 5.6.11 Details for “Increased Condenser Surface Area” Design Option........................ 5-25 

Table 5.6.12 Properties of Standard and Enhanced Condenser Coil ........................................ 5-26 

Table 5.6.13 Baseline Specifications........................................................................................ 5-27 

Table 5.6.14 Energy Consumption Model Numerical Constants and Assumptions................. 5-30 

Table 5.6.15 Summary of Changes to Infiltration Load Calculation in the NOPR.................. 5-37 

Table 5.7.1 Figure, Table, and Page Numbers for Cost-Efficiency Results............................ 5-38 

Table 5.7.2 Cost-Efficiency Data for the VCT.RC.L Equipment Class.................................. 5-39 

Table 5.7.3 Cost-Efficiency Data for the VOP.RC.M Equipment Class................................. 5-40 

Table 5.7.4 Cost-Efficiency Data for the SVO.RC.M Equipment Class................................. 5-41 

Table 5.7.5 Cost-Efficiency Data for the HZO.RC.L Equipment Class.................................. 5-42 

Table 5.7.6 Cost-Efficiency Data for the HZO.RC.M Equipment Class................................. 5-43 

Table 5.7.7 Cost-Efficiency Data for the VCT.RC.M Equipment Class................................. 5-44 

Table 5.7.8 Cost-Efficiency Data for the VOP.RC.L Equipment Class.................................. 5-45 

Table 5.7.9 Cost-Efficiency Data for the SOC.RC.M Equipment Class ................................. 5-46 

Table 5.7.10 Cost-Efficiency Data for the VOP.SC.M Equipment Class ................................ 5-47 

Table 5.7.11 Cost-Efficiency Data for the SVO.SC.M Equipment Class ................................ 5-48 

Table 5.7.12 Cost-Efficiency Data for the HZO.SC.L Equipment Class ................................. 5-49 

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Table 5.7.13 Cost-Efficiency Data for the HZO.SC.M Equipment Class ................................ 5-50 

Table 5.7.14 Cost-Efficiency Data for the HCT.SC.I Equipment Class................................... 5-51 

Table 5.7.15 Cost-Efficiency Data for the VCT.SC.I Equipment Class................................... 5-52 

Table 5.7.16 Cost-Efficiency Data for the VCS.SC.I Equipment Class................................... 5-53 

Table 5.8.1 Offset Factors........................................................................................................ 5-56 

Table 5.9.1 Extension Multipliers for Remote and Self-Contained Equipment Without Doors . 5-

58 

Table 5.9.2 Extension Multipliers by Equipment Class .......................................................... 5-60 

LIST OF FIGURES 

Figure 5.3.1 Flow Diagram of Engineering Methodology ......................................................... 5-5 

Figure 5.4.1 Components of Manufacturer Production Cost...................................................... 5-7 

Figure 5.4.2 Manufacturer Production Cost Assessment Stages ................................................ 5-8 

Figure 5.4.3 Part Count by Equipment Class and Subsystem................................................... 5-10 

Figure 5.4.4 Weight by Equipment Class and Subsystem........................................................ 5-11 

Figure 5.4.5 Manufacturer Production Cost by Equipment Class and Subsystem ................... 5-12 

Figure 5.6.1 Components of the Energy Consumption Model ................................................. 5-31 

Figure 5.7.1 Cost-Efficiency Curve for the VCT.RC.L Equipment Class ............................... 5-39 

Figure 5.7.2 Cost-Efficiency Curve for the VOP.RC.M Equipment Class .............................. 5-40 

Figure 5.7.3 Cost-Efficiency Curves for the SVO.RC.M Equipment Class............................. 5-41 

Figure 5.7.4 Cost-Efficiency Curves for the HZO.RC.L Equipment Class.............................. 5-42 

Figure 5.7.5 Cost-Efficiency Curve for the HZO.RC.M Equipment Class .............................. 5-43 

Figure 5.7.6 Cost-Efficiency Curve for the VCT.RC.M Equipment Class .............................. 5-44 

Figure 5.7.7 Cost-Efficiency Curve for the VOP.RC.L Equipment Class ............................... 5-45 

Figure 5.7.8 Cost-Efficiency Curve for the SOC.RC.M Equipment Class............................... 5-46 

Figure 5.7.9 Cost-Efficiency Curve for the VOP.SC.M Equipment Class............................... 5-47 

Figure 5.7.10 Cost-Efficiency Curve for the SVO.SC.M Equipment Class............................. 5-48 

Figure 5.7.11 Cost-Efficiency Curve for the HZO.SC.L Equipment Class.............................. 5-49 

Figure 5.7.12 Cost-Efficiency Curve for the HZO.SC.M Equipment Class............................. 5-50 

Figure 5.7.13 Cost-Efficiency Curve for the HCT.SC.I Equipment Class............................... 5-51 

Figure 5.7.14 Cost-Efficiency Curve for the VCT.SC.I Equipment Class............................... 5-52 

Figure 5.7.15 Cost-Efficiency Curve for the VCS.SC.I Equipment Class ............................... 5-53 

Figure 5.8.1 Illustration of Offset Factor................................................................................ 5-54 

Figure 5.9.1 Illustration of Extension of Standard Level........................................................ 5-57 

Figure 5.10.1 Material Price Sensitivity for the VOP.RC.M Equipment Class........................ 5-61 

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 EE-2006-STD-0126 COMMENT 23.2
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CHAPTER 5. ENGINEERING ANALYSIS 

5.1 INTRODUCTION 

The engineering analysis establishes the relationship between manufacturer production 

cost and energy consumption for the commercial refrigeration equipment (CRE) covered in this 

rulemaking. This equipment includes commercial ice-cream freezers; self-contained commercial 

refrigerators, commercial freezers, and commercial refrigerator-freezers without doors; and 

remote condensing commercial refrigerators, commercial freezers, and commercial refrigeratorfreezers. The “cost-efficiency” relationship serves as the basis for cost-benefit calculations in 

terms of individual customers, manufacturers, and the Nation. In determining this relationship, 

the U.S. Department of Energy (DOE) estimates the increase in manufacturer production cost 

(MPC) associated with technological changes that reduce the energy consumption of the baseline 

models. 

The primary inputs to the engineering analysis are baseline information and data for each 

equipment class addressed in the market and technology assessment (Chapter 3) and technology 

options from the screening analysis (Chapter 4). Additional inputs include cost and energy 

consumption data that DOE estimated using a cost model and an energy-consumption model, 

respectively. The primary output of the engineering analysis is a set of cost-efficiency curves 

(both analytically derived and industry-supplied curves), and a manufacturer markup used to 

convert MPC to manufacturer selling price (MSP). In the subsequent markups analysis (Chapter 

6), DOE determines customer prices by applying distribution markups, sales tax, and contractor 

markups. After applying these markups, the data serve as inputs to the building energy-use and 

end-use load characterization (Chapter 7) and the life-cycle cost and payback period analyses 

(Chapter 8). 

This chapter discusses the equipment classes DOE analyzed, representative baseline 

units, sensitivity to material prices, and use of alternative refrigerants. The chapter also covers 

the methodology DOE used to develop MPC, estimate energy consumption and cost-efficiency 

curves, and extend the analysis to low-shipment volume equipment classes. 

5.2 EQUIPMENT CLASSES ANALYZED 

In the advance notice of proposed rulemaking (ANOPR) engineering analysis, DOE did 

not directly analyze all covered equipment classes. This methodology has been maintained in 

the notice of proposed rulemaking (NOPR) engineering analysis. DOE used the shipment data 

presented in the market and technology assessment (recreated in Table 5.2.1) to prioritize the 

analysis by eliminating equipment classes with fewer than 100 annual shipments. DOE analyzed 

 EE-2006-STD-0126 COMMENT 23.2
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the 14 remaining high-shipment volume equipment classes. One additional equipment class, the 

VOP.RC.L equipment class, was added after discussions with manufacturers.a

According to Air-Conditioning and Refrigeration Institute (ARI) equipment shipments 

data, these 15 equipment classes represent 98 percent of the shipments of covered commercial 

refrigeration equipment. Table 5.2.2 shows the 15 equipment classes (out of 38 total) DOE 

analyzed in the engineering analysis, organized by equipment family, condensing unit type, and 

rating temperature. 

 

a

 Product class designations consist of a combination (in sequential order separated by periods) of product family 

code (VOP=vertical open, SVO=semivertical open, HZO=horizontal open, VCT=vertical transparent doors, 

VCS=vertical solid doors, HCT=horizontal transparent doors, HCS=horizontal solid doors, or SOC=service over 

counter), operating mode code (RC=remote condensing or SC=self-contained), and rating temperature code 

(M=medium temperature (38°F), L=low temperature (0°F), or I=ice-cream temperature (-15°F)). For example, 

“VOP.RC.M” refers to the “vertical open, remote condensing, medium temperature” product class. See Chapter 3, 

market and technology assessment, for a more detailed explanation of the product class terminology. 

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Table 5.2.1 Shipment Data and Equipment Classes Analyzed 

Equipment 

Family 

Designation 

Condensing 

Unit Type 

Designation 

Rating 

Temperature 

Designation 

Equipment 

Class 

Designation* 

ARI Shipments** 

M (38°F) VOP.RC.M 38,743 

RC L (0°F) VOP.RC.L† 0† 

I (-15°F) VOP.RC.I 0 

M (38°F) VOP.SC.M 6,512 

L (0°F) VOP.SC.L 0 

VOP 

SC 

I (-15°F) VOP.SC.I 0 

M (38°F) SVO.RC.M 29,552 

RC L (0°F) SVO.RC.L 0 

I (-15°F) SVO.RC.I 0 

M (38°F) SVO.SC.M 9,750 

L (0°F) SVO.SC.L 0 

SVO 

SC 

I (-15°F) SVO.SC.I 0 

M (38°F) HZO.RC.M 4,541 

RC L (0°F) HZO.RC.L 14,278 

I (-15°F) HZO.RC.I 0 

M (38°F) HZO.SC.M 838 

L (0°F) HZO.SC.L 1,738 

HZO 

SC 

I (-15°F) HZO.SC.I 0 

M (38°F) VCT.RC.M 2,767 

RC L (0°F) VCT.RC.L 38,483 

I (-15°F) VCT.RC.I 0 

M (38°F) VCT.SC.M‡ 43,374‡ 

L (0°F) VCT.SC.L‡ 2,472‡ 

VCT 

SC 

I (-15°F) VCT.SC.I 1,898 

M (38°F) VCS.RC.M 49 

RC L (0°F) VCS.RC.L 2 

I (-15°F) VCS.RC.I 43 

M (38°F) VCS.SC.M‡ 4‡ 

L (0°F) VCS.SC.L‡ 4,202‡ 

VCS 

SC 

I (-15°F) VCS.SC.I 470 

M (38°F) HCT.RC.M 0 

RC L (0°F) HCT.RC.L 15 

I (-15°F) HCT.RC.I 0 

M (38°F) HCT.SC.M‡ 724‡ 

L (0°F) HCT.SC.L‡ 0‡ 

HCT 

SC 

I (-15°F) HCT.SC.I 9,056 

M (38°F) HCS.RC.M 37 

RC L (0°F) HCS.RC.L 0 

I (-15°F) HCS.RC.I 0 

M (38°F) HCS.SC.M‡ 39,761‡ 

L (0°F) HCS.SC.L‡ 4,109‡ 

HCS 

SC 

I (-15°F) HCS.SC.I 0 

M (38°F) SOC.RC.M 9,312 

RC L (0°F) SOC.RC.L 9 

I (-15°F) SOC.RC.I 0 

M (38°F) SOC.SC.M‡ 1,108‡ 

L (0°F) SOC.SC.L‡ 0‡ 

SOC 

SC 

I (-15°F) SOC.SC.I 0 

* Equipment classes that DOE directly analyzed are shown in bold font. 

**Source: ARI, No. 7 Exhibit B at p. 1. 

† Based on discussions with manufacturers, the VOP.RC.L equipment class was added to the analysis. 

‡ These equipment classes have standards established by Energy Policy Act of 2005 (EPACT 2005) and are therefore not 

covered under this rulemaking.

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Table 5.2.2 Equipment Classes Analyzed in the Engineering Analysis 

Remote Condensing Self-Contained Equipment 

Family Medium Low Ice 

Cream Medium Low Ice Cream 

VOP   

SVO  

Without 

Doors HZO    

VCT   * 

VCS 

HCT 

HCS 

With 

Doors 

SOC 

 Full analysis conducted. 

* Shaded boxes indicate that these equipment classes have standards established by EPACT 2005 and are therefore not 

considered in this rulemaking. 

The engineering analysis considered refrigerators (medium temperature), freezers (low 

temperature), and ice-cream freezers (ice-cream temperature) individually, but did not consider 

refrigerator-freezers directly (combinations of compartments at different temperatures). 

Although DOE did not explicitly analyze refrigerator-freezers in the engineering analysis, it did 

develop a method to combine the standards for refrigerators, freezers, and ice-cream freezers to 

create standards for refrigerator-freezers. Because of the similarities in construction, 

components, and features, DOE believes refrigerator-freezers have a cost-efficiency relationship 

comparable to refrigerators and freezers. Thus DOE assumed that standards developed 

separately for refrigerators and freezers can be applied to refrigerator-freezers. The NOPR 

Federal Register notice describes in detail the methodology used to combine standards for 

refrigerators and freezers into standards for refrigerator-freezers. 

5.3 METHODOLOGY OVERVIEW 

This section describes the analytical methodology DOE used in the engineering analysis. 

In this rulemaking, DOE is adopting a design-option approach. For all 15 equipment classes 

directly analyzed, DOE used the analytically derived curves developed using a design-option 

approach in the downstream analyses. ARI provided four industry-supplied curves for the four 

highest shipment volume equipment classes (VCT.RC.L, VOP.RC.M, SVO.RC.M, and 

HZO.RC.L). These curves were used as a check against the four corresponding curves DOE 

developed to allow DOE and stakeholders to verify the validity of the engineering model. 

Figure 5.3.1 shows a flow diagram of that methodology and the corresponding sections in 

this chapter, starting with models and sub-analyses on the left, and ending with results on the 

right. DOE developed the cost and energy-consumption models in the engineering analysis. The 

sub-analyses are the markups analysis and the matched pair analysis. The results of the 

engineering analysis are 15 analytically derived cost-efficiency curves (four of which have been 

validated by industry-supplied curves), and two sensitivity analyses. 

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Figure 5.3.1 Flow Diagram of Engineering Methodology 

The foundation of the engineering analysis is the 15 curves DOE developed. These 

analytically derived curves were developed using a design option analysis on the selected 15 

equipment classes. In the markups analysis, DOE developed a markup between manufacturer 

production cost MPC and MSP. DOE used this markup to convert the MPC (developed in the 

cost model) to MSP for comparison to the industry-supplied curves. 

DOE used the data submitted by ARI to check its engineering analysis. ARI submitted 

four cost-efficiency curves developed using an efficiency-level approach in the form of 

calculated daily energy consumption (CDEC) versus manufacturer list price (MLP). These 

industry-supplied curves were for the VCT.RC.L, VOP.RC.M, SVO.RC.M, and HZO.RC.L 

equipment classes. As part of the markups analysis, DOE estimated the average industry 

discount from MLP to MSP (the list price discount). DOE used this discount to convert the 

industry-supplied curves into CDEC versus MSP. 

As explained in section 5.2, some equipment classes have very low or no shipments and 

were not included in the direct analysis. To develop standards for these equipment classes, DOE 

developed extension factors for 23 low shipment volume classes using analytical correlations. 

Section 5.8 explains this methodology. 

Cost Model 

(section 5.4) 

Energy 

Consumption 

Model 

(section 5.6) 

15 Analytically 

Derived CostEfficiency 

Curves 

(CDEC versus 

MPC) 

4 IndustrySupplied Cost 

Efficiency 

Curves* 

(CDEC versus 

MLP)

Markups 

Analysis 

(section 5.5) 

Extension 

Analysis 

(section 5.9) 

15 Analytically 

Derived CostEfficiency 

Curves 

(CDEC versus 

MSP) 

(section 5.7) 

15 Analytically 

Derived CostEfficiency 

Curves 

(CDEC versus 

MSP) 

CDEC = Calculated Daily Energy Consumption 

LIST = List price 

MPC = Manufacturer Production Cost 

MSP = Manufacturer Selling Price 

* VCT.RC.L, VOP.RC.M, SVO.RC.M, HZO.RC.L 

Offset Factors 

(section 5.8)

Extension 

Factors (section 

Sensitivity 5.9) 

Analyses 

(section 5.10) 

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DOE developed offset factors for the NOPR engineering analysis as a way to correct 

standards for smaller-sized equipment. Because cost-efficiency curves were typically developed 

for large equipment sizes (e.g., a 12-foot VOP.RC.M case or a 5-door VCT.RC.L case), the 

resulting standard equations could be unfair to smaller-sized cases. In general, the loads a 

particular case is subject to do not go to zero as the size of the case is decreased. Certain 

components of the refrigeration load (such as the conduction end effects) remain constant. These 

constant loads affect smaller cases disproportionately. Offset factors are intended to 

approximate these constant loads and provide a second end point for the line that will become the 

standard equation (the first end point being one of the values of energy consumption determined 

in the engineering analysis). Section 5.8 describes the methodology DOE used to develop offset 

factors. 

The primary results of the engineering analysis are a set of cost-efficiency curves, in the 

form of MSP versus CDEC, for 15 equipment classes. For four of these equipment classes, the 

DOE cost-efficiency curves are validated by the industry-supplied curves. The secondary results 

of the engineering analysis are two sensitivity analyses, a set of offset factors, and a set of 

extension factors. One sensitivity analysis deals with commodity prices performed on the 

VOP.RC.M cost-efficiency curve. The other is a sensitivity analysis of alternative refrigerants. 

The offset factors will be used in formulating standards equations, while the extension factors 

will be used to extend standards developed for the 15 primary equipment classes to the 

remaining 23 equipment classes. 

5.4 COST MODEL 

DOE used a cost model to estimate the MPC of commercial refrigeration equipment. 

This approach involved disassembling a unit from the VCT.SC.M equipment class, analyzing the 

materials and manufacturing processes, and developing a parametric spreadsheet model flexible 

enough to cover all equipment classes. The manufacturing cost model estimated MPC and 

reported it in aggregated form to maintain confidentiality of sensitive cost data. DOE obtained 

input from stakeholders on the MPC estimates and assumptions to confirm accuracy. The cost 

model was applied directly to 7 of the 15 covered equipment classes, and the results were 

extended to 6 of the remaining equipment classes. The cost of remaining two equipment classes 

was estimated using available MLP information discounted to MPC. 

5.4.1 Manufacturer Production Cost Estimates and Assumptions 

Manufacturer production cost is the sum of direct labor, direct material, and overhead 

(including investment depreciation). Other non-production cost elements include selling, general 

and administrative, research and development, and interest. Together, these costs make up the 

MPC, shown in Figure 5.4.1. 

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Figure 5.4.1 Components of Manufacturer Production Cost 

The cost of specific models―or costs to individual manufacturers―will vary, depending 

on the equipment’s precise characteristics, the actual manufacturing processes, the equipment 

mix in the factory, and other elements. There are also considerable differences in the levels of 

vertical integration (companies with a large market share and/or revenue base tend to be more 

vertically integrated than their smaller competitors) that affect cost structure and thus the cost of 

equipment. Yet, potentially all manufacturers buy at least some of their parts and/or subsystems 

from outside vendors. 

The CRE market includes producers that span the range from mass-customized 

equipment to tailored, one-off fabricators. Most equipment listed in catalogs uses platforms that 

are then customized to meet the particular needs of customers. Depending on the manufacturer 

and the degree of customization, engineering costs can thus represent a significant portion of the 

MPC. 

DOE made a number of simplifying assumptions to reflect common industry practice. 

For example, DOE assumed that the cabinets for the VCT equipment family are made in-house, 

but the entire door system (frames, doors, frame heaters, lights, ballasts, etc.) is purchased as an 

assembled sub-system from a door manufacturer. Further, DOE assumed that completed heat 

exchanger assemblies, fan motors and blades, or compressor sleds for self-contained units are 

also purchased as completed sub-systems that need to be integrated into the finished case. 

Since there was only one equipment teardown from which to draw data regarding 

manufacturing practices, DOE built a parametric model that allowed the scaling of most input 

factors. The assumptions behind the model are based on published data by manufacturers, 

general industry practice (based on site visits), manufacturer interviews, and previously 

published DOE reports. DOE compared the model results to published unit data, list prices, and 

stakeholders comments. For example, DOE compared listed shipping weights with the 

calculated weights for cabinets and doors. 

The lack of detailed teardowns for every equipment class and the varying degrees of 

vertical integration in the industry make calculating representative investment requirements 

difficult. Not only does the market share vary for each manufacturer across every equipment 

class, the scale of operations also varies greatly. It is also quite likely that high-volume 

Manufacturer Production 

Cost (MPC) 

Full Production Cost Non-Production Cost 

Research & Interest 

Development 

General & 

Administrative 

Direct Overhead Selling 

Material 

Direct 

Labor 

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manufacturers derive a cost advantage based on their purchasing volume for common raw 

materials and purchased parts alike. Lacking detailed data, DOE did not try to account for lowversus high-volume purchasing power. 

DOE updated the cost model in the NOPR engineering analysis to reflect improved 

understanding of the various cost components that make up the full manufacturing production 

cost. This included changes to the calculation of factory overhead, depreciation, and indirect 

labor. 

5.4.2 Structure of the Cost Model Spreadsheet 

DOE used a detailed, component-focused manufacturing cost assessment methodology to 

estimate the MPC of each equipment class analyzed in the cost model, taking into account, for 

example, direct materials, direct labor, and factory overhead costs. Figure 5.4.2 shows the three 

major steps in generating the MPC. 

Figure 5.4.2 Manufacturer Production Cost Assessment Stages 

The first step in the MPC assessment was creating a complete and structured bill of 

materials (BOM) from the disassembly of a commercial refrigerator with transparent doors 

(VCT.SC.M). DOE dismantled the commercial refrigerator and characterized each part 

according to weight, manufacturing processes, dimensions, material, and quantity. The BOM 

includes the costs for materials, components, and fasteners, and provides estimates for the cost of 

raw materials and purchased parts. DOE based assumptions about the sourcing of parts and inhouse fabrication on industry experience, information in trade publications, and discussions with 

manufacturers. DOE conducted interviews and plant visits with manufacturers to ensure 

accuracy in methodology and pricing. 

Following the development of a detailed BOM, DOE identified the major manufacturing 

processes and developed the spreadsheet model. Table 5.4.1 lists these processes. DOE 

estimated fabrication process cycle times and entered them into the BOM. For this analysis, 

DOE used $24 per hour as the average fully burdened labor rate based on the typical annual 

wages and benefits of industry employees. In the final step of the cost assessment, DOE 

estimated assembly times and associated direct labor costs. Once the cost estimate for each unit 

was finalized, DOE prepared a detailed summary of relevant components, subassemblies, and 

processes. 

Bill of 

Materials 

Fabrication 

Processes Assembly 

Processes 

Raw 

Materials 

Finished 

Materials 

Purchased Parts

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Table 5.4.1 Major Manufacturing Processes 

Fabrication Finishing Assembly/Joining 

Fixturing Washing Adhesive Bonding 

Stamping/Pressing Powder Coating Spot Welding 

Brake Forming De-burring Seam Welding 

Cut and Shearing Polishing Inspecting & Testing 

Insulating 

5.4.3 Material Prices 

DOE determined the cost of raw materials by using prices for copper, steel, and 

aluminum from the American Metals Market.1 DOE obtained prices for rifled and unrifled 

copper tubing directly from a tubing manufacturer. There have been drastic fluctuations in metal 

prices over the last few years. To account for these large fluctuations, DOE used prices of 

metals that reflect a 5-year average of the Bureau of Labor Statistics Producer Price Indices 

(PPIs) spanning 2002 to 2006 with an adjustment to 2006$.2 DOE used the PPIs for steel mill 

products and for copper rolling, drawing, and extruding, and then adjusted to 2006$ using the 

gross domestic product implicit price deflator.3

Between 2003 and 2006, the price of steel rose over 60 percent and the price of copper 

rose over 140 percent. Because DOE used a 5-year average in material prices from 2002 to2006, 

these drastic increases are normalized to some extent to better represent long-term material price 

averages. Because it is not clear if these material price trends will continue, DOE conducted a 

sensitivity analysis to illustrate the effect of raw material price increases on the cost of 

commercial refrigeration equipment (section 5.10.1). 

5.4.4 Results 

DOE reported the cost model results as a core case cost for seven analyzed equipment 

classes: VCT.RC.L, VOP.RC.M, SVO.RC.M, HZO.RC.L, HCT.SC.I, HZO.SC.M, and 

VCT.SC.I. The core case cost is the cost of the structure and other features, but excludes all 

components that relate to design options (such as fans, doors, and evaporator coils) and special 

exterior materials (such as signage and other customer-specified options). Figure 5.4.3 through 

Figure 5.4.5 show the part count, weight, and cost, respectively, for the seven equipment classes 

directly analyzed in the cost model. 

Figure 5.4.3 details the part count by equipment class, cabinet size, and sub-system. The 

large number of cabinet parts is driven primarily by fasteners holding all the sheet metal parts 

together. The distinction between inner, outer, and other cabinet parts represents DOE’s best 

effort to disaggregate the various cabinet categories. “Other” can include some fascia and 

structural elements that help keep the inner and outer skins in alignment. The condenser and 

evaporator descriptors attempt to capture all components outside the heat exchangers that are 

related to condensers and evaporator circuits. The electrical section mainly captures the cost of 

wiring for the ballasts. 

 EE-2006-STD-0126 COMMENT 23.2
5-10

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

VCT.RC.L VOP.RC.M SVO.RC.M HZO.RC.L HCT.SC.I HZO.SC.M VCT.SC.I

Part Count (#)

Outer Cabinet

Inner Cabinet

Cabinet-Other

Wiring/Electric

Evaporator-Other

Condenser-Other

Fasteners

Figure 5.4.3 Part Count by Equipment Class and Subsystem 

Figure 5.4.4 summarizes the weight that each subsystem contributes to the overall weight 

of baseline CRE units of different lengths. These calculated weights are for the basic case only 

and do not incorporate the weight of doors or frames (in the VCT or VCS equipment families), 

compressor sleds (for SC units), heat exchangers, or other design options. Thus, depending on 

the equipment class, the weight reported in this figure is lighter compared to manufacturerreported shipping weights for completed units. 

The weight of commercial refrigeration equipment is heavily influenced by the weight of 

the inner, outer, and cabinet base assemblies. This equipment is built to withstand years of use, 

and the shipping weights of the cabinets reflect this necessity. The degree to which a design 

option adds weight and expense is largely driven by the subsystem. For example, the design 

options include doors with two to three panes of glass. While adding coatings to the glass may 

reduce the energy consumption without a weight impact, a design option calling for additional 

panes will require stronger door hinges and frames. 

 EE-2006-STD-0126 COMMENT 23.2
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0

200

400

600

800

1,000

1,200

1,400

VCT.RC.L VOP.RC.M SVO.RC.M HZO.RC.L HCT.SC.I HZO.SC.M VCT.SC.I

Weight (lb)

Outer Cabinet

Inner Cabinet

Insulation

Cabinet-Other

Wiring/Electric

Evaporator-Other

Condenser-Other

Fasteners

Figure 5.4.4 Weight by Equipment Class and Subsystem 

The actual MPC of this equipment is driven by the processes used to make them, the cost 

of the underlying raw and purchased materials, and the labor required to assemble them into a 

working commercial refrigerator. Figure 5.4.5 shows the MPC for the basic cases discussed in 

this section. 

When the costs are considered by percentage, the inner cavity assembly dominates the 

overall cost due largely to the higher raw material costs; the manufacturing steps required to 

form, shape, and paint these parts; and the time and effort required to assemble and seal them. 

Exterior parts that are not visible to the supermarket consumer tend to be made of 

uncoated galvanized cold rolled steel, remain unpainted, and usually do not require nearly as 

much work to be prepared for assembly. As expected, freestanding units like those in the 

HZO.SC.M equipment class tend to have higher relative costs for their exterior cabinet 

assemblies, which have ten highly visible surfaces, compared to units in the VCT.RC.L 

equipment class, which have six surfaces. 

 EE-2006-STD-0126 COMMENT 23.2
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0

500

1,000

1,500

2,000

2,500

3,000

VCT.RC.L VOP.RC.M SVO.RC.M HZO.RC.L HCT.SC.I HZO.SC.M VCT.SC.I

Cost (US$)

Outer Cabinet

Inner Cabinet

Insulation

Cabinet-Other

Wiring/Electric

Evaporator-Other

Condenser-Other

Fasteners

Figure 5.4.5 Manufacturer Production Cost by Equipment Class and Subsystem 

DOE developed basic case costs (as MPC) for the seven equipment classes. As Table 

5.4.2 illustrates, these results were extended to six of the remaining equipment classes directly 

analyzed in the engineering analysis. Because of the complexity of construction, the cost of the 

remaining two equipment classes (SOC.RC.M and VOP.RC.L) was estimated using MLP 

information from several manufacturers. DOE discounted the MLP values to MPC, and 

subtracted the estimated costs of known components (fan motors, lighting, etc.) to arrive at a 

basic case cost. These basic case costs (in the form of MPC) were incorporated into an 

engineering spreadsheet, where the costs for various design options were added and markups 

were applied. 

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Table 5.4.2 Extension of Cost Model Estimates to Other Equipment Classes 

Developed in Cost Model Extended to 

VCT.RC.L VCT.RC.M 

VOP.RC.M VOP.SC.M 

SVO.RC.M SVO.SC.M 

HZO.RC.L HZO.RC.M 

HCT.SC.I - 

HZO.SC.M HZO.SC.L 

VCT.SC.I VCS.SC.I 

5.5 MANUFACTURER MARKUP AND LIST PRICE MARKUP 

At each stage of the distribution chain, manufacturers, wholesalers, and contractors apply 

a markup to cover their operating costs and profit margins. In the engineering analysis, DOE 

determined a manufacturer markup, and applied it to the MPC to arrive at the MSP. Wholesaler, 

contractor, and other markups are determined in the markups analysis, Chapter 6 of the TSD. 

The manufacturer markup was calculated as the market share weighted average value for 

the industry. For the ANOPR, DOE developed this manufacturer markup by examining several 

major CRE manufacturers’ gross margin information from annual reports and Securities and 

Exchange Commission (SEC) 10-K reports. The manufacturers DOE analyzed account for 

approximately 80 percent of the CRE market. Each company is a subsidiary of a more 

diversified parent company that manufactures equipment other than commercial refrigeration 

equipment. Because the 10-K reports do not provide gross margin information at the subsidiary 

level, the estimated markups represent the average markups that the parent company applies over 

its entire range of equipment offerings and does not necessarily represent the manufacturer 

markup of the subsidiary. The result of the ANOPR analysis shows that the average 

manufacturer markup is 1.39. However, following discussions with manufacturers during the 

manufacturer impact analysis (MIA) interviews (Chapter 13), DOE adjusted the markups to be 

more representative of the industry. An aggregation of the MIA interview responses gives a 

market share weighted average manufacturer markup value of 1.32. DOE used this updated 

manufacturer markup with the MPC values from the engineering analysis to arrive at the MSP 

values used in the GRIM. 

DOE also estimated an industry list price markup, which is a markup on the MSP that 

gives the MLP. DOE understands that manufacturers typically offer a discount off the MLP, 

which depends on various factors such as the relationship with the customer, and the volume and 

type of equipment being purchased. For this estimate, DOE relied on information gathered on 

self-contained commercial refrigeration equipment, since list price information is readily 

available and typically published by manufacturers. A review of the data for self-contained 

equipment shows that the list price markup is typically 2.0. During manufacturer interviews, 

some CRE manufacturers agreed with the 2.0 markup estimate, while others stated the estimate 

was somewhat high. DOE further verified the estimate by obtaining list price quotes from 

several remote condensing equipment manufacturers. Because list price markup is highly 

uncertain and depends on many factors, DOE applied the same estimated list price markup 

across each equipment class to simplify the analysis. DOE compared the analytically derived 

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cost-efficiency curves to the industry-supplied cost-efficiency curves using the list price markup 

estimate. (See section 5.7 for these comparisons.) 

5.6 ENERGY CONSUMPTION MODEL 

The energy consumption model is the second of two key analytical models used in 

constructing cost-efficiency curves. This model estimates the CDEC of commercial refrigeration 

equipment in kilowatt hours (kWh) at various performance levels using a design-options 

approach. The model is specific to the types of equipment covered under this rulemaking 

(described in Chapter 3 of this TSD), but is sufficiently generalized to model the energy 

consumption of all covered equipment classes. DOE developed the energy consumption model 

as a Microsoft Excel spreadsheet, which is available to the public on DOE’s website 

(http://www.eere.energy.gov/buildings/appliance_standards/ commercial_products.html). 

Appendix A provides instructions for using the spreadsheet. 

For a given equipment class, the model estimates the daily energy consumption for the 

baseline and the energy consumption of several levels of performance above the baseline. The 

model calculates each performance level separately. For the baseline level, a corresponding cost 

is calculated using the cost model (section 5.4). For each level above the baseline, the cost 

increases of the various design options are used to recalculate the cost. 

These are substantive changes that have been made to improve the accuracy of the 

engineering spreadsheet, and affect the numerical output of the model. Other formatting, layout, 

and editorial changes have been made to the spreadsheet, but are not detailed here. Changes to 

specific model components are detailed in their respective sections. Major revisions include 

changes to infiltration load calculation (section 5.6.7.6), radiation load calculation (section 

5.6.7.4), LED lighting energy use (section 5.6.3.1), and the self-contained compressor model 

(section 5.6.7.2). 

5.6.1 Screened-In Technologies 

DOE analyzed the following 15 technology options: 

• higher efficiency lighting 

• higher efficiency lighting ballasts 

• remote lighting ballast location 

• higher efficiency evaporator fan motors 

• evaporator fan motor controllers 

• higher efficiency evaporator fan blades 

• increased evaporator surface area 

• low pressure differential evaporators 

• insulation increases or improvements 

• defrost mechanism 

• defrost cycle control 

• higher efficiency compressors (self-contained equipment only) 

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• increased condenser surface area (self-contained equipment only) 

• higher efficiency condenser fan motors (self-contained equipment only) 

• higher efficiency condenser fan blades (self-contained equipment only) 

5.6.2 Screened-In Technologies Not Considered in the Engineering Analysis 

In the market and technology assessment (Chapter 3), DOE defined an initial list of 

technologies that can reduce the energy consumption of commercial refrigeration equipment. In 

the screening analysis, DOE first narrowed this list by eliminating from consideration those 

technologies that can reduce annual energy consumption of commercial refrigeration equipment 

but do not reduce CDEC. DOE screened out the remaining technologies that were not 

technologically feasible, were not practical to manufacture, reduced equipment utility, or were 

considered unsafe. 

The remaining list of screened-in technologies became one of the inputs to the 

engineering analysis. However, for reasons noted below, DOE did not incorporate all of these 

technologies in the energy consumption model. These include location of remote lighting 

ballasts, evaporator fan motor controllers, higher efficiency evaporator and condenser fan blades, 

insulation increases or improvements, low-pressure differential evaporators, defrost cycle 

controls, and defrost mechanisms. 

5.6.2.1 Remote Lighting Ballast Location 

Relocation of fluorescent lamp ballasts outside the refrigerated space can reduce energy 

consumption by lessening the refrigeration load on the compressor. However, for the majority of 

commercial refrigeration equipment currently manufactured, ballasts are already located in 

electrical trays outside the refrigerated space, in either the base or top of the equipment. The 

notable exceptions are the equipment classes in the VCT equipment family, where ballasts are 

most often located on the interior of each door mullion. 

Most CRE manufacturers purchase doors for VCT units that are preassembled with the 

entire lighting system in place rather than configured for separate ballasts. DOE believes that 

most CRE manufacturers choose these kinds of doors because it would be labor intensive and 

time consuming to relocate these ballasts at the factory and wire separate ballasts. Also, the 

potential energy savings are small, since modern electronic ballasts are very efficient and 

typically contribute only a few watts each to the refrigeration load. Therefore, DOE did not 

consider remote relocation of ballasts as a design option. 

5.6.2.2 Evaporator Fan Motor Controllers 

Evaporator fan motor controllers allow fan motors to run at variable speed to match 

changing conditions in the case. For evaporator fan motor controllers, there is some opportunity 

for energy savings since frost buildup and removal creates differing pressure drops across the 

evaporator coil. Theoretically, less fan power is required when the coil is free of frost. The coil 

also would operate at a more stable temperature during frost build-up. However, the 

effectiveness of the air curtain in equipment without doors is very sensitive to changes in airflow, 

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and fan motor controllers could disrupt the air curtain. The potential of disturbance to the air 

curtain, which could lead to higher infiltration loads, does not warrant the use of evaporator fan 

motor controllers in equipment without doors, even if there were some reduction in fan energy 

use. In addition, savings from evaporator fan motor controllers in all equipment types would be 

small. Therefore, DOE did not consider evaporator fan motor controllers as a design option. 

5.6.2.3 Higher Efficiency Evaporator and Condenser Fan Blades 

Higher efficiency evaporator and condenser fan blades reduce motor shaft power 

requirements by moving air more efficiently. Current technology used in commercial 

refrigeration equipment is stamped sheet metal or plastic axial fan blades. These fan blades are 

lightweight and inexpensive. DOE was not able to identify any axial fan blade technology that is 

significantly more efficient than what is currently used, but did identify one alternative fan blade 

technology that might improve efficiency: tangential fan blades. They can produce a wide, even 

airflow, and have the potential to allow for increased saturated evaporator temperature (SET) 

through improved air distribution across the evaporator coil, which would reduce compressor 

power. However, tangential fan blades in small sizes are themselves less efficient at moving air, 

and thus require greater motor shaft power. Because of these competing effects, DOE did not 

consider tangential fan blades as a design option. 

5.6.2.4 Improved Insulation 

Improvements to insulation material include better polyurethane foams and vacuum 

panels. In consultation with insulation material manufacturers, DOE determined that there are 

no significant differences in “grades” of insulation material, so most equipment manufacturers 

are already using the best commercially available foam materials in their equipment. Vacuum 

panels are an alternative form of insulation, but they may degrade in performance in time as 

small leaks develop. In addition, vacuum panels cannot be penetrated by fasteners, and do not 

provide the rigidity of “foamed-in-place” panels that polyurethane insulation creates. Therefore, 

DOE did not consider insulation thickness increases or improvements as a design option. 

DOE also did not include insulation thickness increases as a design option in the ANOPR 

because thicker insulation must either borrow volume from the refrigerated space or increase the 

overall size of the equipment cabinet. Because the outer dimensions of commercial refrigeration 

equipment are limited (e.g., by interior dimensions of shipping containers), it is often not 

practical to increase the overall size of the cabinet. In addition, reducing the volume of the 

refrigerated space to accommodate thicker insulation would reduce the utility of the equipment. 

DOE understands that in equipment classes where conduction makes up a significant 

portion of the total refrigeration load, an insulation thickness increase can lead to small, but 

significant energy savings. DOE decided to add insulation thickness increase as a design option 

in the NOPR because it is cost-effective in several equipment types, most notably self-contained 

ice-cream freezers with doors. DOE also considered improvements to the efficiency (e.g.,

thermal conductance) of doors in the design options analysis. Higher efficiency doors reduce the 

overall heat gain to the case by using better frame materials, more panes of glass, and better (or 

more) insulation in the doorframe. 

 EE-2006-STD-0126 COMMENT 23.2
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5.6.2.5 Low-Pressure Differential Evaporators 

Low-pressure differential evaporators reduce energy consumption by reducing the power 

of evaporator fan motors. However, in space-constrained equipment such as commercial 

refrigeration equipment, this reduction usually comes from a decrease in evaporator coil surface 

area, which generally requires a lower SET to achieve the same discharge air temperature and 

cooling potential. This, in turn, results in a reduction in compressor efficiency. Because of these 

competing effects, DOE did not consider low-pressure differential evaporators as a design 

option. 

5.6.2.6 Defrost Cycle Control 

Defrost cycle control can reduce energy consumption by reducing the frequency and 

duration of defrost periods. The majority of equipment currently manufactured already uses 

partial defrost cycle control in the form of cycle termination control. However, defrost cycle 

initiation is still scheduled at regular intervals. Full defrost cycle control would involve a 

method of detecting frost buildup and initiating defrost. As described in the market and 

technology assessment (Chapter 3), this could be accomplished through an optical sensor or 

sensing the temperature differential across the evaporator coil. However, both of these methods 

are unreliable due to fouling of the coil with dust and other surface contaminants. This becomes 

more of an issue as the display case ages. Because of these issues, DOE did not consider defrost 

cycle control as a design option. 

5.6.2.7 Defrost Mechanisms 

Defrosting for medium-temperature equipment is typically accomplished with off-cycle 

defrost. Because off-cycle defrost uses no energy (and decreases compressor on-time), there is 

no defrost design option capable of reducing defrost energy in cases that use off-cycle defrost. 

Some medium temperature cases and all low temperature and ice-cream temperature cases use 

supplemental heat for defrost. Electric resistance heating (electric defrost) is commonly used in 

these cases. An alternative to electric defrost in those cases that require supplemental defrost 

heat is hot-gas defrost. This is most often seen in remote condensing equipment and involves 

using the hot compressor discharge gas to warm the evaporator from the refrigerant side. The 

test procedure for commercial refrigeration equipment is not capable of quantifying the energy 

expenditure of the compressor during a hot-gas defrost cycle. Therefore, DOE did not consider 

it as a design option. 

5.6.3 Design Options 

After conducting the screening analysis and removing from consideration those 

technologies described above, DOE implemented the remaining technologies as design options 

in the energy consumption model: 

• higher efficiency lighting and ballasts for VOP, SVO, HZO, and SOC equipment 

families (horizontal fixtures); 

• higher efficiency lighting and ballasts for VCT equipment family (vertical fixtures); 

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• higher efficiency evaporator fan motors; 

• increased evaporator surface area; 

• increased insulation thickness; 

• improved doors for VCT equipment family, low temperature (hinged, 30 x 67 

inches); 

• improved doors for VCT equipment family, medium temperature (hinged, 30 x 67 

inches); 

• improved doors for HCT equipment family, ice-cream temperature (sliding, 18 x 20.5 

inches); 

• improved doors for SOC equipment family, medium temperature (sliding, 20 x 24 

inches); 

• higher efficiency condenser fan motors (for self-contained equipment only); 

• increased condenser surface area (for self-contained equipment only); and 

• higher efficiency compressors (for self-contained equipment only). 

Each design option has two to three technology levels, ranging from the minimum (worst 

performing) to the maximum (best performing) technology. The design options and the 

technology levels for each design option are described below. 

5.6.3.1 Higher Efficiency Lighting and Ballasts 

Lighting is an important characteristic of commercial refrigeration equipment because it 

makes the product visible to the consumer. Lighting systems operate continuously and provide 

an opportunity for significant energy savings. As lighting system efficiency increases, 

reductions in total case energy consumption can be achieved through a direct reduction in 

electricity consumption by the lighting system, and a reduction of heat inside the case, thereby 

reducing compressor work. 

It is important that product illumination not degrade with higher design option levels, 

which would decrease the utility of the equipment. DOE made every effort to maintain constant 

system light output among design options. This approach meant that DOE had to consider 

lighting as a system, rather than distinguishing lamps and ballasts as separate design options. 

This approach becomes more important when considering light emitting diode (LED) lighting 

systems, which don’t use ballasts, as fluorescent lighting systems do. 

Although LED systems generally have lower efficacy than the fluorescent systems they 

replace, the fixtures are more efficient at directing light onto the product. Although the total 

lumen output of LED systems is lower than comparable fluorescent systems, the amount of light 

incident on the product (illuminance) is roughly equivalent. Consultation with CRE 

manufacturers, lighting manufacturers, and other technical experts indicate that current LED 

technology provides product lighting that is adequate, and in most cases comparable to 

fluorescent lighting. 

To account for the variation in design between equipment families, DOE used two 

lighting design options in the energy-consumption model. DOE used the “higher efficiency 

lighting and ballasts for VOP, SVO, HZO, and SOC equipment families” design option for 

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lighting in a horizontal configuration, and the higher efficiency lighting and ballasts for VCT 

equipment family design option for the lighting in a vertical configuration. The VCS and HCS 

equipment families do not require lighting because they are not designed to display food, while 

the HCT equipment family typically does not have lighting because it relies on store ambient 

lighting. Therefore, DOE did not consider lighting design options for these three equipment 

families. 

Because of the horizontal configuration of shelving and the linear nature of display-case 

lineups in the VOP, SVO, HZO, and SOC equipment families, fluorescent lighting is typically 

installed with the bulb in a horizontal plane. Details for the “higher efficiency lighting and 

ballasts for VOP, SVO, HZO, and SOC equipment families” design option are shown in Table 

5.6.1. Remote condensing versions of these display cases are most often sold in 8-foot and 12-

foot sections, using multiples of 4-foot fluorescent lamps to continuously light the entire width of 

the case. Self-contained versions are commonly sold in 4-foot lengths, so that a single 4-foot 

fluorescent lamp will light the full width of the case. Therefore, 4-foot lamps were specified for 

all lighting systems in the horizontal configuration. These lamps also were required to have a 

color temperature of 3,500 Kelvin (K), which is typical for this type of equipment. Fluorescent 

T12 magnetic and electronic systems were not considered for the horizontal lighting because a 

survey of existing equipment and discussions with manufacturers indicate that this technology is 

no longer used in these equipment classes. 

In the NOPR engineering analysis, DOE revised its cost assumption for LED lighting 

used in the VOP, SVO, HZO, and SOC equipment families (horizontal 4-foot fixtures) and in the 

VCT equipment family (vertical 5-foot fixtures). DOE based LED lighting costs on an LED 

retrofit case study, but revised some of its assumptions based on conversations with 

manufacturers. Specifically, DOE revised the assumption regarding the relative cost of one-row 

and two-row LED fixtures, giving more weight to the labor involved in manufacturing the 

fixtures. DOE assumed labor accounts for approximately half of the fixture cost, and that LED 

chips account for the majority of the material costs. Thus, removing half of the LED chips 

would reduce the cost by approximately 25 percent. DOE therefore assumed a one-row fixture 

costs 75 percent of a two-row fixture. DOE also assumed that a 4-foot fixture costs 

approximately 90 percent of a 5-foot fixture. These two changes cause the original equipment 

manufacturer (OEM) cost of LED fixtures to increase for the equipment families for which they 

are an option: VOP, SVO, HZO, and SOC families (horizontal fixtures) and VCT (vertical 

fixtures). 

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Table 5.6.1 Details for Lighting for VOP, SVO, HZO, and SOC Equipment 

Families Design Option 

Level Description Lamp Type 

Lamp 

Rated 

Power 

(W)

Lamp 

Rated Light 

Output 

(Lumens)

System 

Efficacy 

(Lumens/W)

System 

Light 

Output 

(Lumens)

T8 4 ft, T8 Elec. F32T8 32.0 2,850 85.0 2,679 

T8S 4 ft, Super T8 Elec. F32T8/HL 32.0 3,100 91.4 2,697 

LED 4 ft, LED LED 4 ft 16.4 820 50.0 820 

Because of the vertical configuration of the doors in the VCT equipment family, 

fluorescent lamps are typically installed vertically behind the mullions between doors. Table 

5.6.2 shows details for the “lighting for VCT equipment family” design option. Such lighting 

systems typically consist of a single 5-foot or 6-foot lamp and a single ballast per mullion and 

are installed at each end of the case. All lighting systems in the vertical configuration were 

specified to have 5-foot lamps and a color temperature of 4,100 K, which is typical for this 

equipment family. 

Table 5.6.2 Details for Lighting for VCT Equipment Family Design Option 

Level Description Lamp Type 

Lamp 

Rated 

Power 

(W)

Lamp 

Rated Light 

Output 

(Lumens)

System 

Efficacy 

(Lumens/W)

System 

Light 

Output 

(Lumens)

T8 5 ft, T8 Elec. F58T8/835 58.0 5,400 93.1 5,400 

LED 5 ft, LED - 41.0 2,050 50.0 2,050 

5.6.3.2 Higher Efficiency Evaporator Fan Motors 

In conjunction with fan blades, fan motors are necessary for transferring heat from the 

display case to the refrigerant and, in the case of self-contained equipment, rejecting heat from 

the refrigerant into the ambient air. Fan motors are also responsible for maintaining product 

temperatures and air curtains on open cases. They must operate virtually continuously, and 

therefore use a significant amount of energy. As motor efficiency increases, reductions in total 

case energy consumption are achieved through a direct reduction both in electricity consumption 

and waste heat inside the case, reducing compressor work. 

Table 5.6.3 shows details for the evaporator fan motor design option. DOE considers 

shaded-pole motors (SPM) as the minimum technology, permanent split capacitor (PSC) motors 

as the mid-level technology, and brushless direct current (DC) or electronically commutated 

motors (ECMs) as the maximum technology level. DOE took the motor efficiency levels listed 

in Table 5.6.3 taken from American National Standards Institute (ANSI)/ARI Standard 1200-

2006 (ARI 1200), Performance Rating of Commercial Refrigerated Display Merchandisers and 

Storage Cabinets. 

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Table 5.6.3 Details for Evaporator Fan Motor Design Option 

Shaded-Pole Motor (SPM) Permanent Split Capacitor 

(PSC) Motor 

Brushless DC Motor 

Rated (ECM) 

Power 

(W) 

Actual 

Power 

(W)

Efficiency 

(%)

Actual 

Power 

(W)

Efficiency 

(%)

Actual 

Power 

(W)

Efficiency 

(%)

15.0 75.0 20 51.7 29 22.7 66 

9.0 45.0 20 31.0 29 13.6 66 

6.0 30.0 20 20.7 29 9.1 66 

5.6.3.3 Increased Evaporator Surface Area 

Evaporator coils are another component necessary for transferring heat from the display 

case to the refrigerant. Table 5.6.4 shows details for the evaporator coil design option. In view 

of available information, DOE considered a minimum and a maximum technology level for this 

design option. For each level, DOE specified an overall UA-valueb and a coil cost. The UAvalue is normalized to the standard coil, and the coil cost is normalized to the heat removal 

capacity of the coil. This allowed DOE to apply these details of coil design across all equipment 

classes. In consultation with outside experts, DOE determined that applying the same coil 

improvements to different sized coils would result in similar performance improvements. 

Table 5.6.4 Details for Evaporator Coil Design Option 

Level Description Normalized UA (-) 

Normalized Coil Cost 

($/Btu/hr)

EVAP1 Standard Coil 1 $0.0358 

EVAP2 High-Performance Coil 1.667 $0.0500 

DOE based the details of coil construction (Table 5.6.5) on a baseline and prototype highperformance coil evaluated in a study by Oak Ridge National Laboratory.4

 The highperformance coil uses a combination of enhancements to the heat transfer surfaces that increased 

its overall UA-value. These enhancements include higher fin pitch, rifled tubing, and different 

tube spacing. In sum, these improvements allow the prototype coil to run at a SET that is 6° 

warmer than the baseline coil and maintain the same discharge air temperature (30°F) and heat 

removal capacity (12,990 British thermal units per hour (Btu/hr)). 

 

b

 The overall UA-value is the product of the overall heat transfer coefficient (Btu/h-ft2-°F) and the total surface area 

(ft

2

) of the coil. This value can be derived from the total heat transfer rate of the coil (Btu/h) divided by the average 

temperature difference between the discharge air and the saturated evaporator temperature (∆T). 

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Table 5.6.5 Properties of Standard and Enhanced Evaporator Coil 

Property Standard Coil High-Performance Coil 

Overall Width (in) 81 81 

Overall Height (in) 7 5/8 7 1/2 

Overall Depth (in) 12 13 9/16 

Tube Rows per Circuit 12 12 

Number of Parallel Circuits 4 6 

Tubing Material Copper Copper 

Tubing Outer Diameter (in) 1/2 3/8 

Tubing Wall Thickness (in) 0.012 0.012 

Tubing Inner Surface Smooth Rifled 

Fin Material Aluminum Aluminum 

Fin Surface Flat Flat 

Fin Dimensions (in) 5.415 x 7.5 (5 front rows) 8.66 x 7.5 (all rows) 7.581 x7.5 (7 rear rows) 

Fin Pitch (fins per inch) 3 (5 front rows) 2 (all rows) 4 (7 rear rows) 

Because compressor performance is directly related to SET, reductions in total case 

energy consumption are realized through an improved energy efficiency ratio (EER) at the 

condensing unit. In consultation with outside experts, DOE determined that applying the same 

coil improvements to different sized coils and at different temperatures would result in similar 

SET improvements. 

5.6.3.4 Increased Insulation Thickness 

DOE included increased foam insulation thickness as a design option in the NOPR 

engineering analysis because it is cost-effective in several equipment types, most notably selfcontained ice-cream freezers with doors. A half-inch increase in insulation thickness was 

modeled for all equipment classes. DOE added this increase in thickness to the baseline value of 

insulation thickness and recalculated the conduction load (section 5.6.7.5). The cost of 

increasing the insulation thickness is based on a sunk cost per unit, considering foam fixture 

engineering and tooling costs, production line lifetime, and number of fixtures and units 

produced. Table 5.6.6 provides details of the assumptions used to calculate the additional cost of 

insulation thickness increases. DOE assumed that the cost increase due to additional foam 

material is insignificant compared to the cost of upgrading foam fixtures. 

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Table 5.6.6 Insulation Thickness Increase Assumptions 

Item Value Notes 

Cost to Upgrade Single 

Insulation Fixture $100,000 

Number of Fixtures 25 Based on a survey of the number of products offered by each 

manufacturer 

Engineering Costs $5,000,000 Assumes $100,000 per year salary and one month to complete 

redesign per machine plus one month for testing 

Interest Rate 7.0% 

Product Line Lifetime 

(years) 7.0 

Units per Year 35,000 

Sunk Cost Per Machine $39.76 Assumes changes in material costs are negligible compared to 

fixture and engineering costs 

5.6.3.5 Improved Doors 

Transparent doors allow refrigerated products to be displayed to consumers while 

keeping cold air inside of the display case. On freezers and some refrigerators, glass doors must 

be heated to prevent frost from forming and rubber seals from freezing. These “anti-sweat” 

heaters often run continuously and consume significant amounts of energy. Transparent doors 

also allow heat to radiate into the display case and have a lower insulation value than solid walls. 

Reductions in total case energy consumption can be achieved both by improving the overall 

insulation value (U-factor) of the door and by reducing the required anti-sweat heater power. 

A wide variety of door types are used on the equipment covered in this rulemaking. Door 

construction and performance can vary by equipment family as well as operating temperature of 

the case. To account for this variation, DOE developed four separate design options for the 

different door types represented in the 15 equipment classes that DOE analyzed. For all door 

design options, DOE estimated the thermal performance of the door (expressed as an overall Ufactor) using information about door construction from manufacturers and WINDOW 5 software 

available from Lawrence Berkley National Laboratory.5

Doors for the VCT equipment family operating at low temperature are hinged and are 30 

inches wide and 67 inches tall with three panes of glass. Table 5.6.7 shows details of thermal 

performance and anti-sweat heater requirements for this door type. 

DOE considered two technology levels for this design option: the high-performance door 

that uses a combination of low-emissivity coating, frame material, and inert fill-gas to reduce the 

overall U-factor; and a standard door. DOE updated the design option for glass doors for vertical 

equipment with glass doors (VCT equipment family) in the NOPR engineering analysis. Based 

on discussions with manufacturers and data from manufacturer specification sheets, the antisweat heater power for both the baseline and high-efficiency doors increased from 160 to 200 for 

baseline doors and from 60 to 110 for high-efficiency doors. DOE did not update the cost data 

because more accurate data was unavailable. 

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Table 5.6.7 Details for Doors for VCT Equipment Family, Low Temperature 

Design Option 

Level Description Overall U-Factor 

(Btu/hr-ft-°F)

Anti-Sweat Heater 

Power (W/door)

DOOR1 Standard Door 0.547 200 

DOOR2 High-Performance Door 0.276 110 

Doors for the VCT equipment family operating at medium temperature are hinged and 30 

inches wide and 67 inches tall with two panes of glass. Table 5.6.8 shows details of thermal 

performance and anti-sweat heater requirements for this door type. 

DOE considered two technology levels for this design option. The high-performance 

door uses a combination of low-emissivity coating, frame material, and inert fill-gas to reduce 

the overall U-factor compared to the standard door and eliminate anti-sweat heater power. DOE 

updated the design option for glass doors for medium temperature VCT equipment in the NOPR 

engineering analysis. Based on discussions with manufacturers and data from manufacturer 

specification sheets, the anti-sweat heater power for both the baseline and high-efficiency doors 

increased from 60 to 100 for baseline doors and from 0 to 50 for high-efficiency doors. DOE did 

not update the cost data because more accurate data was unavailable. 

Table 5.6.8 Details for Doors for VCT Equipment Family, Medium Temperature 

Design Option 

Level Description Overall U-Factor 

(Btu/hr-ft-°F)

Anti-Sweat Heater 

Power (W/door)

DOOR1 Standard Door 0.560 100 

DOOR2 High-Performance Door 0.478 50 

Doors for the HCT equipment family operating at ice-cream temperature (HCT.SC.I and 

HCT.RC.I equipment class) are sliding and18 inches wide and 20.5 inches tall with one pane of 

glass. Table 5.6.9 shows details of thermal performance and anti-sweat heater requirements for 

this door type. 

DOE considered two technology levels for this design option: a high-performance door 

that uses a combination of low-emissivity coating, frame material, and an extra pane with inert 

fill-gas to reduce the overall U-factor; and a standard door. Typically, a high-performance door 

does not require anti-sweat heater power. 

Table 5.6.9 Details for “Doors for HCT Equipment Family, Ice-Cream 

Temperature” Design Option 

Level Description Overall U-Factor 

(Btu/hr-ft-°F) 

Anti-Sweat Heater 

Power (W/door) 

DOOR1 Standard Door 1.046 0 

DOOR2 High-Performance Door 0.377 0 

Doors for the SOC equipment family operating at medium temperature are of the sliding 

type and are 24 inches wide and 20 inches tall with two panes of glass. Table 5.6.10 shows 

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details of door thermal performance and anti-sweat heater requirements for this door type. DOE 

considered two technology levels for this design option: a high-performance door that uses a 

combination of low-emissivity coating, frame material, and inert fill-gas to achieve a reduced 

overall U-factor; and a standard door. Typically, a high-performance door does not require antisweat heater power. 

Table 5.6.10 Details for Doors for SOC Equipment Family, Medium Temperature 

Design Option 

Level Description Overall U-Factor 

(Btu/hr-ft-°F) 

Anti-Sweat Heater 

Power (W/door) 

DOOR1 Standard Door 0.672 0 

DOOR2 High-Performance Door 0.320 0 

5.6.3.6 Higher Efficiency Condenser Fan Motors 

 The condenser fan motor design option applies only to those equipment classes that are 

self-contained. Details for the condenser fan motor design option are identical to those shown in 

Table 5.6.3. As with evaporator fan motors, the SPM is the minimum technology, the PSC 

motor is the mid-technology, and the DC motor or ECM is the maximum technology level. 

Because condenser fan motors are outside the refrigerated space, efficiency improvements only 

affect the direct electrical consumption of the motors and not the total case heat load. 

5.6.3.7 Increased Condenser Surface Area 

Table 5.6.11 shows details for this design option, which only applies to self-contained 

equipment classes. Details of coil construction are based on data from tear-downs by Southern 

California Edison’s Refrigeration and Thermal Test Center (RTTC).6 Based on this information, 

DOE considered both minimum and maximum technology levels for this design option. For 

each level, DOE specified an overall UA-value and a coil cost. The UA-value is normalized to 

the standard coil, and the coil cost is normalized to the heat removal capacity of the coil. This 

approach allowed DOE to apply the details of coil design across all self-contained equipment 

classes. In consultation with outside experts, DOE determined that applying the same coil 

improvements to different sized coils would result in similar performance improvements. 

Table 5.6.11 Details for “Increased Condenser Surface Area” Design Option 

Level Description Normalized 

UA (-) Normalized Coil Cost ($/Btu/h) 

COND1 Standard Coil 1.00 $0.0146 

COND2 High-Performance Coil 2.56 $0.0439 

Table 5.6.12 shows details of coil construction. The high-performance coil uses a 

combination of enhancements to the heat transfer surfaces that increased its overall UA-value. 

These enhancements include higher fin pitch, rifled tubing and different tube spacing. These 

improvements allow the prototype coil to run at a saturated condenser temperature (SCT) that is 

10°F cooler than the baseline coil while maintaining the same heat rejection rate (1,600 Btu/hr). 

Because compressor performance is directly related to SCT, reductions in total case energy 

consumption are achieved through an improved EER at the condensing unit. 

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Table 5.6.12 Properties of Standard and Enhanced Condenser Coil 

Property Standard Coil High-Performance Coil 

Overall Width (in) 12.5 24 

Overall Height (in) 10 10 

Overall Depth (in) 2.25 3 

Tube Rows per Circuit 28 16 

Number of Parallel Circuits 3 2 

Tubing Material Copper Copper 

Tubing Outer Diameter (in) 3/8 3/8 

Tubing Wall Thickness (in) 0.012 in 0.012 in 

Tubing Inner Surface Smooth Rifled 

Fin Material Aluminum Aluminum 

Fin Surface Flat Flat 

Fin Pitch (fins per inch) 6 7 

5.6.3.8 Higher Efficiency Compressors 

The compressor design option applies only to self-contained equipment classes. In 

consultation with compressor manufacturers and external technical experts, DOE determined that 

two levels of technology were applicable for the compressor design option. The minimum 

technology level is a standard single-speed hermetic compressor, and the maximum technology 

level is a high-efficiency single-speed hermetic compressor. (See section 5.6.5 for a discussion 

of why DOE did not consider variable-speed compressors.) Reductions in total case energy 

consumption are achieved through a reduction in compressor power consumption. 

Several manufacturers provided DOE performance data for standard single-speed 

hermetic compressors a range of capacities applicable to the covered equipment (1,500 - 20,000 

Btu/h). DOE used this data to find appropriately sized compressors when developing each 

design-option curve. (See section 5.6.7.2 for information on the calculation of compressor 

energy consumption.) Although several compressor manufacturers produce high-efficiency 

compressors, little data are currently available on their performance. Therefore, DOE 

approximated a set of high-efficiency compressors by adjusting the power consumption of the 

standard compressors using a constant multiplier. DOE developed this multiplier through its 

own research and consultation with outside experts. (See section 5.6.5 for details on this 

multiplier.) 

In the NOPR, DOE updated the assumptions used to estimate the changes in cost and 

efficiency for high-efficiency single-speed compressors. Based on discussions with 

manufacturers and other experts, DOE concluded that the assumptions used in the ANOPR (a 

10-percent increase in cost results in a 20-percent reduction in energy use) overstated the actual 

efficiency gains that are possible in today’s compressors. Therefore, DOE revised its 

assumptions (a 5-percent increase in cost results in a 10-percent reduction in compressor energy 

use). Per dollar, efficiency gains are equivalent with these new assumptions, but the overall 

magnitude of power reduction is lower, as well as the cost premium. This change affects only 

the self-contained equipment classes analyzed in the engineering analysis. 

 EE-2006-STD-0126 COMMENT 23.2
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5.6.4 Baseline Specifications 

DOE defined baseline specifications (or case design specifications) for each equipment 

class. These specifications include dimensions, numbers of components, temperatures, nominal 

power ratings, and other case features that are necessary to calculate energy consumption. In 

conjunction with the lowest technological level of each design option (section 5.6.3), the baseline 

specifications define the energy consumption and cost of the typical minimum technology 

equipment on the market. Table 5.6.13 shows the specifications and units that DOE defined for 

each equipment class. 

Table 5.6.13 Baseline Specifications 

Specification Units 

Case Length ft 

Case Gross Refrigerated Volume ft3

Case Total Display Area ft2

Number of Lamps in Conditioned Space # 

Number of Lamps Not in Conditioned Space # 

Number of Ballasts in Conditioned Space # 

Number of Ballasts Not in Conditioned Space # 

Evaporator Fan Nominal Rated Wattage W 

Number of Evaporator Fans per Case # 

Condenser Fan Nominal Rated Wattage W 

Number of Condenser Fans per Case # 

Defrost Mechanism Type (Off-Cycle, Electric, Manual) n/a 

Defrost Time per Day hr 

Defrost and Drain Heater Power W 

Anti-Sweat Power Other Than Doors W 

Condensate Pan Heater Power W 

Average Case Temperature °F 

Saturated Evaporator Temperature (SET) Nominal °F 

Saturated Condenser Temperature (SCT) Nominal °F 

Compressor Oversize Factor (>1) n/a 

Nominal Insulation Thickness in 

Wall Area ft2

Number of Doors # 

Single Door Area ft2

Non-Door Glass Area ft2

Case Interior Surface Area ft2

Air-Curtain Height ft 

Air-Curtain Angle from Vertical ° 

Infiltrated Air Mass lb/hr 

DOE established baseline specifications for each equipment class modeled in the 

engineering analysis by reviewing available manufacturer data, selecting several representative 

units from that data, and then aggregating the physical characteristics of the selected units. This 

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process created a representative unit for each equipment class with average characteristics for 

physical parameters (e.g., volume, total display area), and minimum performance of energyconsuming components (e.g., fans, lighting). Appendix B provides these numerical 

specifications for each equipment class, as well as changes to baseline design specifications 

relative to the ANOPR analysis. 

5.6.5 Non-Numerical Assumptions 

In developing the energy consumption model, DOE made certain general non-numerical 

assumptions about the analysis, as well as specific assumptions about load components and 

design options. 

DOE assumed that all conditions are based on new equipment tested in a controlledenvironment chamber subjected to ARI 1200, which references the ANSI/American Society of 

Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 72-2005 

(ASHRAE 72), Method of Testing Commercial Refrigerators and Freezers. Manufacturers that 

certify their equipment to comply with Federal standards will be required to test new units to this 

test method, which specifies ambient temperature, humidity, light level, and other requirements. 

DOE assumed that there is no pull-down load associated with re-shelving products since 

the test procedure does not address product re-shelving. Product re-shelving is the act of loading 

new products into refrigerated display cases as existing products are sold. Typically, commercial 

refrigeration equipment is not designed to pull down the temperature of warm products, but only 

to display products that were already chilled or frozen in a refrigerated storage unit. 

DOE also assumed that there are no pull-down loads associated with post-defrost periods. 

During defrost periods, the compressor (or the flow of refrigerant for remote condensing cases) 

stops and the coil warms to a temperature above freezing (aided by electric resistance heating in 

the case of electric defrosts). After the evaporator coil has been cleared of frost, the merchandise 

in the case will typically have warmed several degrees. The merchandise must be returned to 

normal operating temperature when the refrigeration cycle resumes, adding an additional load to 

the condensing unit. Between equipment families and even within equipment classes there is a 

large variation in defrost mechanism, defrost cycle time, temperature recovery time, and product 

mass. Because of the uncertainty of these factors, DOE was unable to accurately calculate the 

defrost pull-down load and did not include it in the model. Sample calculations show that this 

load may only account for two to four percent of the total refrigeration load for a VOP.RC.M 

case, or roughly one to two percent of the total daily energy consumption. 

DOE did not consider hot-gas defrost as a design option for defrost mechanisms in 

remote condensing cases (Chapter 4 of this TSD). During hot-gas defrost, hot refrigerant from 

the compressor rack bypasses the condenser and expansion device and is piped directly to the 

evaporator coil, melting the frost on the coil. The ASHRAE 72 test procedure provides a method 

for measuring the total refrigeration load during steady-state conditions, and does not capture the 

energy added to a display case during a hot-gas defrost cycle. Therefore, DOE did not consider 

this technique. 

 EE-2006-STD-0126 COMMENT 23.2
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DOE did not consider liquid suction heat exchangers (LSHX) as a design option (Chapter 

4 of this TSD). As with hot-gas defrost, the effects of LSHX cannot be measured with the 

ASHRAE 72 test procedure. 

DOE did not consider variable-speed compressors as a compressor design option. 

Variable-speed compressors reduce energy consumption under real-world conditions by 

matching their capacity to the refrigeration load, which can change due to variation in ambient 

conditions and product loading. This eliminates the inefficiencies that occur due to mismatched 

capacity and load in a single-speed compressor during part-load operation. The ASHRAE 72 

test procedure prescribes steady-state conditions. Thus, a variable-speed compressor would be 

limited to single-speed operation, the EER would be no better than a properly sized single-speed 

compressor, and no appreciable energy savings would result. Similarly, under ASHRAE 72, the 

performance of a high-efficiency variable-speed compressor would be comparable to a highefficiency single-speed compressor. 

5.6.6 Numerical Constants and Assumptions 

In developing the energy consumption model, DOE identified constants and made 

assumptions concerning numerical values used in the analysis. These include ambient 

conditions, financial assumptions, and parameters necessary to calculate the component and nonelectric loads. Table 5.6.14 shows details of these assumptions. 

 EE-2006-STD-0126 COMMENT 23.2
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Table 5.6.14 Energy Consumption Model Numerical Constants and Assumptions 

Numerical Constants and Assumptions Number Source 

Test Chamber Temperature (°F) 75 ASHRAE 727

Test Chamber Relative Humidity (%) 55 ASHRAE 727

Test Chamber Pressure (pounds per square 

in (psi), absolute) 14.7 Assumed 

Manufacturer Markup ($/$) 1.32 Publicly available corporate financial data 

List Price Markup ($/$) 2.00 DOE estimate based on discussion with 

manufacturers 

Fraction of Anti-Sweat Heater Power into 

Case (W/W) 0.7 DOE estimate based on discussions with manufacturers 

Fraction of Lighting Power into Case for 

Lamps Outside of Air Curtain (W/W) 0.5 Electric Power Research Institute (EPRI), Supermarket Simulation Tool (SST) v3.08

Lighting Operating Time per Day (hr) 24 Assumed 

Thermal Conductivity of Foam Insulation 

(Btu-in/hr-ft2-F) 0.125 Discussions with foam manufacturers; Manufacturer data sheets 

Convective Film Coefficient Inside Case 

Walls (Btu/hr-ft2-F) 4.00 Communication with Southern California Edison, RTTC 

Convective Film Coefficient Outside Case 

Walls (Btu/hr-ft2-F) 1.46 Communication with RTTC 

Overall U-Value of Single-Pane Glass 

(Btu/hr-ft2-F) 1.059 Lawrence Berkeley National Laboratory 

WINDOW 5 Software5

Emissivity of Test Chamber Walls (-) 0.9 Communication with RTTC 

Emissivity of Case Inner Walls (-) 0.9 Communication with RTTC 

Area of Test Chamber Walls (ft2) 1000 Communication with RTTC 

Case Interior Relative Humidity (%) 65 R. Faramarzi, Efficient Display Case 

Refrigeration, ASHRAE Journal, November 19999

Evaporator Coil Overall Bypass Factor (%) 17 DOE estimate 

High-Efficiency Compressor Cost 

Premium 5% Communication with manufacturers 

High-Efficiency Compressor Power 

Reduction 10% Communication with manufacturers 

5.6.7 Model Components 

Figure 5.6.1 presents a schematic showing the components in the energy consumption 

model. The model calculates energy consumption in two major subsections (expressed as 

kWh/day): compressor energy consumption and component energy consumption. Component 

energy consumption is the sum of electrical energy directly consumed by each fan motor, lamp, 

defrost and drain heater, anti-sweat heater, and pan heater. 

Compressor energy consumption is calculated from the total heat load (expressed as 

Btu/h) and one of two compressor models: one version for remote condensing equipment, and 

one for self-contained equipment. The total heat load is a sum of the component load and the 

non-electric load. The component load is a sum of the heat emitted by evaporator fan motors, 

 EE-2006-STD-0126 COMMENT 23.2
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lighting, defrost heaters, drain heaters, and anti-sweat heaters inside and adjacent to the 

refrigerated space (condenser fan motors and pan heaters are outside the refrigerated space and 

do not contribute to the component heat load). The non-electric load is the sum of the heat 

contributed by radiation through glass and openings, heat conducted through walls and doors, 

and warm air infiltration through openings. 

Figure 5.6.1 Components of the Energy Consumption Model 

5.6.7.1 Component Energy Consumption 

Fan motor energy consumption is calculated by summing the power draw of each 

evaporator and condenser fan motor, and multiplying the total motor power by the total running 

time over a 24-hour period. (This calculation assumes that evaporator and condenser fans run 

continuously when off-cycle defrost is used, and are turned off during defrost when electric 

defrost is used). 

Lighting energy consumption is calculated by summing the power draw of each lamp and 

ballast, and multiplying the total by the total operating time of the lighting system over a 24-hour 

period. (This calculation assumes that lighting operates continuously.) In the ANOPR, the 

calculation of LED energy use assumed that the LED lighting fixtures at the ends of VCT cases 

were identical to those between doors. With fluorescent fixtures, manufacturers install the same 

lamp whether the lamp is at the end of the case (an end mullion) or between doors (an interior 

Total Heat 

Load 

[Btu/h]

Component 

Load

[Btu/h]

Non-Electric 

Load

[Btu/h]

Fan Motor 

Heat Load

[Btu/h]

Lighting Heat 

Load

[Btu/h]

Radiation 

Load

[Btu/h]

Conduction 

Load

[Btu/h]

Infiltration 

Load

[Btu/h]

Daily Energy 

Consumption [kWh/day]

Compressor 

Energy 

Consumption 

[kWh/day]

Compressor Model 

(ARI 540)

Electric Energy 

Consumption

[kWh/day]

Heat Load 

[Btu/h]

Legend:

Component 

Energy 

Consumption 

[kWh/day]

Fan Motor 

Energy

 Consumption 

[kWh/day]

Lighting 

Energy 

Consumption 

[kWh/day]

 EE-2006-STD-0126 COMMENT 23.2
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mullion). This causes excess of light at the ends of the case, since the light output of a single 

lamp between two doors goes in both directions. Lamps at the ends direct light only on the 

contents behind the end door. 

LED fixtures are inherently scalable, so manufacturers can install an LED fixture in the 

end mullion that uses half the energy (and produces half the light) of fixtures in interior mullions. 

The calculation in the NOPR analysis assumes single-row LED fixtures are used in the end 

mullions. Single-row fixtures are assumed to use half the energy of double-row fixtures in 

interior mullions. 

Defrost and drain heater energy consumption is calculated by summing the power draw 

of each defrost heater and drain heater, and multiplying by the total time the case is in defrost 

operation over a 24-hour period. 

Anti-sweat energy consumption is calculated by summing the power draw of each antisweat heater, and multiplying by the total operating time of the heaters over a 24-hour period. 

(This calculation assumes that anti-sweat heaters run continuously.) 

Pan heater energy consumption is calculated by multiplying the power draw of each pan 

heater by the total operating time of the heater over a 24-hour period. The total operating time is 

calculated as the time it would take to evaporate all of the defrost melt water. 

5.6.7.2 Compressor Energy Consumption 

Compressor energy consumption (CEC) is calculated from the total heat load and one of 

two compressor models: one version for remote condensing equipment and one for selfcontained equipment. Compressor energy consumption for remote condensing equipment is 

calculated using default efficiency values from ARI 1200. Table 1 in ARI 1200 lists remote 

condensing compressor EER in Btu/Wh as a function of adjusted dew point temperature. 

Adjusted dew point (ADP) temperature (°F) is calculated as: 

 ADP = SET – 2°F (for medium temperature) Eq. 5.1

 ADP = SET – 3°F (for low/ice-cream temperature) Eq. 5.2 

where 

SET is the saturated evaporator temperature (°F). 

Once ADP is calculated, Table 1 in ARI 1200 is used to find the corresponding EER 

value. The compressor energy consumption (kWh/day) is then calculated as: 

 CEC = Qtot x (24 - tdefrost) / (EER x 1000) Eq. 5.3

where 

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Qtot is the total heat load (Btu/hr), and 

tdefrost is the total defrost time in a 24-hour period (hr). 

Compressor energy consumption for self-contained equipment is calculated by using the 

compressor model described in section 6.4 of ARI Standard 540-2004 (ARI 540), Performance 

Rating of Positive Displacement Refrigerant Compressors and Compressor Units. This model is 

based on a 10-coefficient polynomial derived from empirical compressor performance data for 

power, mass flow, current, and efficiency. The coefficients are derived for each parameter as a 

function of SET and SCT. Compressor coefficients, or tabulated empirical data (from which 

coefficients can be derived), are available from compressor manufacturers. Similar to the 

method used for remote condensing equipment, the EER of any compressor can be determined 

given a SET and SCT. Using Equation 5.3 above, the compressor energy consumption can be 

determined. 

In the NOPR engineering analysis, DOE revised its rated capacity values for selfcontained compressors. In the ANOPR, rated capacity was listed at standard ASHRAE rating 

evaporator and condenser rating conditions. Because the actual conditions in most commercial 

refrigeration equipment are not at standard rating conditions, listed capacities differed 

significantly from capacities at modeled conditions. The compressor model used a look-up 

function to select the most appropriate compressor based on the total refrigeration load in the 

case and the compressor oversize factor from the baseline design specifications. Because of the 

mismatch of capacity at standard conditions and actual modeled conditions, the capacity of the 

selected compressors was typically overestimated. To compensate, the compressor oversize 

factor was adjusted to an unrealistic level (typically 1) so the model could select the correct 

compressor. 

In the NOPR, the corrected capacity listings required revising the oversize factor for all 

self-contained equipment classes to maintain the selection of the correct compressor size. 

Because no compensation is needed in the updated NOPR model, the compressor oversize 

factors are more realistic (typically 1.4). 

5.6.7.3 Component Load Model 

The component load is the sum of the heat each evaporator fan motor, lamp, defrost and 

drain heater, and anti-sweat heater emits inside and adjacent to the refrigerated space. Each 

component creates waste heat that is rejected to the refrigerated space and must be removed by 

the compressor. 

DOE assumed that all electrical energy the evaporator fan motors consume ends up as 

heat inside the refrigerated space. In any electric motor, irreversibilities in the motor windings, 

bearings, and other mechanical components convert much of the input electrical energy into heat. 

The rest of the energy is converted to moving air inside the case. This moving air is slowed by 

friction and eventually converted to heat as well. 

For lamps inside the refrigerated space, DOE assumed that all electrical energy the lamps 

consumed ends up as heat inside the space. For lamps that are outside the refrigerated space 

 EE-2006-STD-0126 COMMENT 23.2
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(i.e., adjacent to the air curtain), DOE assumed that 50 percent of the electrical energy the lamps 

consumed ends up as heat inside the space. For ballasts inside the refrigerated space, DOE 

assumed that all electrical energy the ballasts consumed ends up as heat inside the space. 

Ballasts outside the refrigerated space do not contribute any heat to the space. 

The phase change that occurs when defrost heaters melt the frost from evaporator coils 

consumes most of the electrical energy that supplied during a defrost period. Over a 24-hour 

period, the total heat of melting is determined by 

Q m H melt frost f water = , Eq. 5.4

where 

Qmelt is the heat of melting (Btu/hr), 

mfrost is the frost mass in a 24-hour period (lbs/hr), and 

Hf,water is the heat of fusion of water (Btu/lb). 

DOE assumed that all the electrical energy that defrost heaters consume, other than what 

is used to melt the frost, ends up as heat inside the refrigerated space. For drain heaters, DOE 

assumed that all electrical energy ends up as heat inside the refrigerated space. 

DOE assumed that on average, 70 percent of the electrical energy consumed by antisweat heaters adjacent to the refrigerated space (frame, rail, glass, sill and air grille heaters) ends 

up as heat inside the space. 

5.6.7.4 Radiation Load Model 

The radiation heat load model accounts for the gray-body radiation between the warm 

surfaces of the surrounding environment (the test chamber) and the cold inner surfaces of the 

refrigerated space. For cases without doors, the net radiation is determined: 

( )

Q

T T

A A F A

rad

room case

room

room room room case room

case

case case

=

−

−

+ +

−

−

σ

ε

ε

ε

ε

4 4

1 1 1

Eq. 5.5 

where 

Qrad is the net radiation load (Btu/h), 

σ is the Stefan-Boltzmann constant (Btu/h-ft2-°F4), 

Troom is the temperature of the room walls (°F), 

Tcase is the temperature of the case inner walls (°F), 

εroom is the emissivity of the room walls (dimensionless), 

εcase is the emissivity of the case inner walls (dimensionless), 

Aroom is the area of the room walls (ft2),

Acase is the area of the interior of the case (ft2), and 

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Fcase-room is the view factor from the case interior to the room walls 

(dimensionless). 

DOE assumed that the wall temperatures of the case was in thermal equilibrium with the 

air temperature in the case, and that the wall temperatures of the room were in thermal 

equilibrium with the air temperature in the room. See Table 5.6.14 for numerical constants 

pertaining to the radiation model. 

DOE made one change to the methodology of calculating the radiation load for cases 

without doors (VOP, SVO, and HZO equipment families). In the ANOPR, DOE estimated the 

view factor from the interior of the case to the walls of the test chamber as 0.025, based on data 

and calculations from the RTTC. This value was kept constant for all cases and sizes, but it is 

clear this value should change somewhat as the geometry and the overall size of the case 

changes. 

In the NOPR, the view factor is calculated separately for each equipment class depending 

on the geometry specific to the baseline design specifications of that class. The view factor from 

the case to the room is calculated as the ratio of total display area (TDA, area of the plane 

separating the case from the room) to the test chamber wall surface area. 

For glass doors and other glass, the net radiation is incorporated into the overall U-value 

of the door calculated by WINDOW 5 (Table 5.6.7 through Table 5.6.10, and Table 5.6.14). The 

WINDOW 5 program specified the environmental conditions in the case and the room for cases 

at medium temperature, low temperature, and ice-cream temperature. See section 5.6.7.5 for a 

discussion of the calculation of the combined radiation and conduction loads for glass doors and 

other glass. 

5.6.7.5 Conduction Load Model 

The conduction load model accounts for the heat conducted through walls and doors. For 

solid walls and doors, the conduction is given by: 

Q A

T T

h

d

k h

cond walls

room case

o

ins

ins i

=

−

+ +

1 1 Eq. 5.6 

where 

Awalls is the area of the exterior of the case (ft2), 

ho is the convective film coefficient on the outside of case walls (Btu/h-ft2-°F), 

hi is the convective film coefficient on the inside of case walls (Btu/h-ft2-°F), 

dins is the insulation thickness (in), and 

kins is the insulation thermal conductivity (Btu-in/h-ft2-°F). 

 EE-2006-STD-0126 COMMENT 23.2
5-36

Because of its high thermal conductivity, the sheet metal that encloses the insulation has 

no significant effect on the conduction load, and therefore was not included in the calculation of 

conduction load. See Table 5.6.14 for numerical constants pertaining to the conduction model. 

For glass doors and other glass, the conduction load is incorporated into the overall Ufactor of the door assembly or glass calculated by WINDOW 5 (Table 5.6.7 through Table 5.6.10 

and Table 5.6.14). The combined radiation and conduction load for glass doors and other glass 

is calculated as: 

Q U A T T ( ) glass overall glass room case = − Eq. 5.7

where 

Uoverall is the overall U-factor, including convection and radiation (Btu/h-ft2-°F), 

and 

Aglass is the area of the glass (ft2). 

5.6.7.6 Infiltration Load Model 

In the ANOPR, infiltration load was calculated using empirical defrost meltwater data 

obtained from manufacturers’ detailed spec sheets. DOE assumed that defrost meltwater could 

be correlated with infiltration load, given certain known parameters such as ambient relative 

humidity. This methodology was calibrated with detailed case load data obtained from Southern 

California Edison for several large-volume equipment classes. 

At the ANOPR public meeting, stakeholders commented that using defrost meltwater 

may not be an accurate way of calculating the infiltration load. They explained that defrost 

meltwater data was a rough estimate of the amount of infiltrated air, and in many cases could 

underestimate the infiltration load. DOE agrees with this assessment and altered its methodology 

accordingly. 

In the NOPR engineering design specifications, DOE replaced the defrost melt water (in 

pounds per hour (lbs/hr)) with infiltrated air (also in lbs/hr) for all equipment classes. DOE 

estimated infiltrated air by using manufacturers’ detailed spec sheets, recognizing that infiltration 

load is the only load component that cannot be directly calculated. DOE calculated other load 

components (internal load, conduction load, radiation load) using physical parameters about each 

case. DOE subtracted these load components from the listed total refrigeration load, and 

assumed that the remaining load is due to infiltration. Table 5.6.15 provides a summary of 

changes to the infiltration load for each equipment class DOE examined in the NOPR. 

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Table 5.6.15 Summary of Changes to Infiltration Load Calculation in the NOPR 

Equipment Class NOPR Infiltrated Air 

Mass (lbs/hr)

NOPR Infiltration Load 

(Btu/hr)

ANOPR Infiltration 

Load (Btu/hr)

VOP.RC.M 860 16,066 16,050 

VOP.RC.L 530 15,643 15,277 

SVO.RC.M 590 11,022 10,982 

HZO.RC.M 250 4,670 620 

HZO.RC.L 140 4,132 1,428 

VCT.RC.M 30 524 210 

VCT.RC.L 30 865 887 

SOC.RC.M 15 267 279 

VOP.SC.M 300 5,605 4,224 

SVO.SC.M 220 4,110 2,816 

HZO.SC.M 100 1,868 620 

HZO.SC.L 100 2,951 1,214 

VCT.SC.I 15 491 391 

VCS.SC.I 15 491 391 

HCT.SC.I 3 98 78 

5.7 COST-EFFICIENCY CURVES 

The result of the engineering analysis is a set of cost-efficiency curves. DOE developed 

15 curves representing the 15 directly analyzed equipment classes, using the baseline 

specifications and design options described above. (See Appendix B for details). The 

methodology for developing curves started with determining the baseline energy consumption 

and manufacturer production cost. Above the baseline, DOE implemented design options from 

lowest to highest payback, and only one design option was implemented at each design option 

level. Design options were implemented until all technologies were at a maximum level. 

ARI created four industry-aggregated curves using an efficiency-level approach. ARI 

presented these curves to DOE in the form of daily energy consumption and manufacturer list 

price normalized by TDA. DOE applied the list price discount developed in the markup section 

(section 5.5) to the industry-supplied curves to arrive at a TDA-normalized MSP. 

The 15 cost-efficiency curves are shown in Figure 5.7.1 through Figure 5.7.15 and in 

Table 5.7.2 through Table 5.7.16 in the form of TDA-normalized daily energy consumption and 

MSP. Figure 5.7.1 through Figure 5.7.4 and Table 5.7.2 through Table 5.7.5 include the 

corresponding industry-supplied data for comparison. Table 5.7.1 shows a list of the 15 

analyzed equipment classes and their corresponding figure, table, and page numbers. Appendix 

B provides more detailed results, including the design options used at each design option level in 

the analytically derived (AD) curves. 

 EE-2006-STD-0126 COMMENT 23.2
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Table 5.7.1 Figure, Table, and Page Numbers for Cost-Efficiency Results 

Equipment Class Figure Table Page Number 

VCT.RC.L* Figure 5.7.1 Table 5.7.2 5-39 

VOP.RC.M* Figure 5.7.2 Table 5.7.3 5-40 

SVO.RC.M* Figure 5.7.3 Table 5.7.4 5-41 

HZO.RC.L* Figure 5.7.4 Table 5.7.5 5-42 

HZO.RC.M Figure 5.7.5 Table 5.7.6 5-43 

VCT.RC.M Figure 5.7.6 Table 5.7.7 5-44 

VOP.RC.L Figure 5.7.7 Table 5.7.8 5-45 

SOC.RC.M Figure 5.7.8 Table 5.7.9 5-46 

VOP.SC.M Figure 5.7.9 Table 5.7.10 5-47 

SVO.SC.M Figure 5.7.10 Table 5.7.11 5-48 

HZO.SC.L Figure 5.7.11 Table 5.7.12 5-49 

HZO.SC.M Figure 5.7.12 Table 5.7.13 5-50 

HCT.SC.I Figure 5.7.13 Table 5.7.14 5-51 

VCT.SC.I Figure 5.7.14 Table 5.7.15 5-52 

VCS.SC.I** Figure 5.7.15 Table 5.7.16 5-53 

* Shown with industry-supplied data. 

** VCS equipment family is normalized by volume.

As stated above, DOE used the cost-efficiency curves from the engineering analysis as an 

input to the life-cycle cost (LCC) analysis to determine the price of commercial refrigeration 

equipment to the customer (Chapter 8). In the LCC analysis, DOE used industry-supplied curves 

for the equipment classes that had industry-supplied curves provided. For all other equipment 

classes, DOE used the AD curves in the LCC analysis. 

 EE-2006-STD-0126 COMMENT 23.2
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Figure 5.7.1 Cost-Efficiency Curve for the VCT.RC.L Equipment Class 

Table 5.7.2 Cost-Efficiency Data for the VCT.RC.L Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDANormalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 1.07 113.17 

AD2 1.04 113.61 

AD3 1.01 114.67 

AD4 0.72 134.42 

AD5 0.71 135.24 

AD6 0.65 147.83 

AD7 0.64 149.55 

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Figure 5.7.2 Cost-Efficiency Curve for the VOP.RC.M Equipment Class 

Table 5.7.3 Cost-Efficiency Data for the VOP.RC.M Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDANormalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 1.09 79.12 

AD2 1.04 79.76 

AD3 0.98 81.30 

AD4 0.95 82.90 

AD5 0.90 87.59 

AD6 0.89 88.58 

AD7 0.76 129.36 

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$50

$70

$90

$110

$130

$150

$170

$190

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40

TDA-Normalized Daily Energy Consumption [kWh/day/ft2]

TDA-Normalized Manufacturer Selling 

Price [$/ft2]

SVO.RC.M

Semivertical Remote Refrigerator without Doors

Figure 5.7.3 Cost-Efficiency Curves for the SVO.RC.M Equipment Class 

Table 5.7.4 Cost-Efficiency Data for the SVO.RC.M Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDANormalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2

) 

AD1 1.09 95.10 

AD2 1.05 95.67 

AD3 0.99 97.04 

AD4 0.97 98.56 

AD5 0.91 102.91 

AD6 0.78 141.73 

AD7 0.77 143.06 

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Figure 5.7.4 Cost-Efficiency Curves for the HZO.RC.L Equipment Class 

Table 5.7.5 Cost-Efficiency Data for the HZO.RC.L Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDANormalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 0.83 93.63 

AD2 0.81 94.12 

AD3 0.77 95.31 

AD4 0.73 97.40 

AD5 0.72 98.56 

 EE-2006-STD-0126 COMMENT 23.2
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Figure 5.7.5 Cost-Efficiency Curve for the HZO.RC.M Equipment Class 

Table 5.7.6 Cost-Efficiency Data for the HZO.RC.M Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 0.60 129.23 

AD2 0.54 129.92 

AD3 0.48 131.58 

AD4 0.45 133.95 

AD5 0.44 135.56 

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Figure 5.7.6 Cost-Efficiency Curve for the VCT.RC.M Equipment Class 

Table 5.7.7 Cost-Efficiency Data for the VCT.RC.M Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 0.51 103.23 

AD2 0.49 103.67 

AD3 0.46 104.72 

AD4 0.35 120.28 

AD5 0.34 121.10 

AD6 0.29 133.69 

AD7 0.29 134.71 

 EE-2006-STD-0126 COMMENT 23.2
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Figure 5.7.7 Cost-Efficiency Curve for the VOP.RC.L Equipment Class 

Table 5.7.8 Cost-Efficiency Data for the VOP.RC.L Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 2.99 143.54 

AD2 2.84 145.32 

AD3 2.65 149.62 

AD4 2.54 156.20 

AD5 2.52 157.02 

AD6 2.51 158.21 

AD7 2.44 179.07 

 EE-2006-STD-0126 COMMENT 23.2
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Figure 5.7.8 Cost-Efficiency Curve for the SOC.RC.M Equipment Class 

Table 5.7.9 Cost-Efficiency Data for the SOC.RC.M Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 0.62 146.36 

AD2 0.59 146.81 

AD3 0.55 147.88 

AD4 0.53 149.08 

AD5 0.51 150.33 

AD6 0.41 180.77 

AD7 0.41 181.81 

AD8 0.40 187.79 

 EE-2006-STD-0126 COMMENT 23.2
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Figure 5.7.9 Cost-Efficiency Curve for the VOP.SC.M Equipment Class 

Table 5.7.10 Cost-Efficiency Data for the VOP.SC.M Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 2.65 145.66 

AD2 2.54 146.49 

AD3 2.50 147.25 

AD4 2.46 148.39 

AD5 2.41 150.23 

AD6 2.30 155.87 

AD7 2.27 157.96 

AD8 2.24 160.71 

AD9 2.06 179.11 

AD10 1.89 226.80 

AD11 1.89 230.37 

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$100

$120

$140

$160

$180

$200

$220

$240

$260

$280

$300

1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00

TDA-Normalized Daily Energy Consumption [kWh/day/ft2]

TDA-Normalized Manufacturer Selling Price 

[$/ft2]

SVO.SC.M

Semivertical Self-Contained Refrigerator without Doors

Figure 5.7.10 Cost-Efficiency Curve for the SVO.SC.M Equipment Class 

Table 5.7.11 Cost-Efficiency Data for the SVO.SC.M Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 2.59 138.92 

AD2 2.47 139.82 

AD3 2.44 140.27 

AD4 2.43 140.71 

AD5 2.40 141.78 

AD6 2.30 146.81 

AD7 2.28 147.88 

AD8 2.26 149.57 

AD9 2.09 165.98 

AD10 1.95 205.92 

AD11 1.94 210.08 

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Figure 5.7.11 Cost-Efficiency Curve for the HZO.SC.L Equipment Class 

Table 5.7.12 Cost-Efficiency Data for the HZO.SC.L Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 3.22 154.04 

AD2 3.03 155.38 

AD3 3.00 155.85 

AD4 2.96 156.99 

AD5 2.80 161.97 

AD6 2.79 162.44 

AD7 2.54 178.69 

AD8 2.53 179.83 

AD9 2.51 184.26 

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Figure 5.7.12 Cost-Efficiency Curve for the HZO.SC.M Equipment Class 

Table 5.7.13 Cost-Efficiency Data for the HZO.SC.M Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 1.60 132.19 

AD2 1.52 132.87 

AD3 1.49 133.34 

AD4 1.45 134.48 

AD5 1.44 134.96 

AD6 1.38 137.83 

AD7 1.26 147.19 

AD8 1.24 148.33 

AD9 1.23 152.76 

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Figure 5.7.13 Cost-Efficiency Curve for the HCT.SC.I Equipment Class 

Table 5.7.14 Cost-Efficiency Data for the HCT.SC.I Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 1.42 202.29 

AD2 1.29 203.93 

AD3 1.24 205.04 

AD4 0.72 225.93 

AD5 0.69 228.61 

AD6 0.65 239.00 

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Figure 5.7.14 Cost-Efficiency Curve for the VCT.SC.I Equipment Class 

Table 5.7.15 Cost-Efficiency Data for the VCT.SC.I Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

TDA-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft2) 

TDA-Normalized 

Manufacturer 

Selling Price 

($/ft2) 

AD1 1.755 134.76 

AD2 1.657 135.45 

AD3 1.607 135.88 

AD4 1.545 136.94 

AD5 1.452 138.95 

AD6 1.323 145.51 

AD7 0.973 165.26 

AD8 0.969 165.70 

AD9 0.875 181.45 

AD10 0.869 182.50 

AD11 0.861 184.55 

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Figure 5.7.15 Cost-Efficiency Curve for the VCS.SC.I Equipment Class 

Table 5.7.16 Cost-Efficiency Data for the VCS.SC.I Equipment Class 

DOE Analytically Derived Data 

Design 

Option 

Level 

V-Normalized 

Daily Energy 

Consumption 

(kWh/day/ft3) 

V-Normalized 

Manufacturer 

Selling Price 

($/ft3) 

AD1 0.565 43.38 

AD2 0.535 43.61 

AD3 0.506 43.91 

AD4 0.471 44.48 

AD5 0.451 45.03 

AD6 0.414 46.82 

AD7 0.410 47.06 

AD8 0.402 48.17 

AD9 0.397 48.74 

Note: The VCS product family is 

normalized by volume. 

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5.8 OFFSET FACTORS 

Equipment energy use (CDEC) scales with equipment size, but smaller equipment tends 

to use more energy per TDA (or per volume) than larger equipment in the same equipment class. 

This extra energy is attributed to components of case load that do not scale with equipment size. 

These load components therefore have a disproportionate effect on the energy consumption of 

small equipment. DOE developed offset factors to account for these load components, 

commonly referred to as “end effects,” as a way to adjust standards to allow more energy use for 

smaller equipment. 

In the ANOPR public meeting, stakeholders raised concerns that standards developed for 

large sizes of equipment would be unfair when applied to smaller equipment in the same class, 

because of the end effects that disproportionately affect smaller equipment. In most equipment 

classes, larger equipment is more common, especially in those classes that are used in grocery 

stores (i.e., remote condensing equipment). In its engineering analysis, DOE developed costefficiency curves for a single size within each equipment class. The representative TDAc

selected for each class was toward the larger end of the equipment available within that class. 

DOE intended for standards to be based on this single point (the point defined by TDA and 

CDEC). In effect, DOE was proposing in the ANOPR to implement standards by requiring 

equipment to meet an energy consumption limit defined by a line drawn between the origin and 

the TDA-CDEC point determined by the engineering cost-efficiency curve. (See the left pane of 

Figure 5.8.1.) As the right pane of Figure 5.8.1 shows, the offset factor fixes the left end of the 

standard equation at a fixed offset on the CDEC axis, effectively providing a higher limit on 

energy consumption for smaller equipment. 

Figure 5.8.1 Illustration of Offset Factor 

 

c

 TDA is used here to illustrate the concept of offset factors. However, this explanation also applies to equipment 

classes that use volume as a normalizing factor. 

 EE-2006-STD-0126 COMMENT 23.2
5-55

A standard equation, then, consists of two components: a size-dependent multiplier 

(slope) and a constant (offset factor). DOE calculated the slope of the standard equation as the 

difference between the CDEC at the analysis point corresponding to the selected standard level 

and the offset factor, divided by the TDA at the analysis point: 

m

CDEC b

TDA

=

−

Eq. 5.10 

where, 

m is the slope of the standard equation, and 

b is the offset factor. 

The standard equation then takes the form: 

CDEC m TDA b MAX = ⋅ + Eq. 5.11 

where CDECMAX is the maximum allowable energy consumption. This form of the 

standard equation also applies to equipment classes that use volume as a normalizing factor. 

In determining offset factors, DOE considered different end effects for each equipment 

family. For all open cases (VOP, SVO, and HZO), DOE considered the effects of heat 

conduction through the case ends, as well as the infiltration load end effects. For vertical closed 

transparent cases (VCT), the conduction through the ends was taken into account, as well as the 

heat load and electrical load of one T8 lamp. DOE considered one T8 lamp because there is 

generally always one more lamp than the number of doors (e.g., six lamps in a five-door case), 

meaning that in a theoretical case with no doors, there would still be one lamp. In the remaining 

equipment families (SOC, HCT, VCS), DOE only considered the conduction effects through the 

case ends. 

To estimate the heat load due to conduction through the case ends for each equipment 

class, DOE used the same methodology that it used to find the conduction through case walls 

(Eq. 5.6). DOE substituted the area of the case ends for the wall area of the entire case to find 

only the heat load caused by conduction through the ends. For the open cases, DOE estimated 

the infiltration load end effects. DOE estimated the infiltration end effects of a VOP.RC.M case 

as 1,100 Btu/h per end,10 and then scaled that value for the other open cases based on the air 

curtain length of each equipment class compared to the air curtain length of the VOP.RC.M case. 

DOE estimated the heat load due to a lamp as 198.08 Btu/h (section 5.6.7.3). 

Once the appropriate heat loads were calculated, DOE summed the applicable heat loads 

for each class. DOE used the total heat load of each individual equipment class to calculate the 

daily energy use of the compressor for that class, using the method described in section 5.6.7.2. 

For all equipment classes except for those in the VCT equipment family, this became the offset 

factor. For VCT equipment, DOE also considered the amount of electrical energy consumed by 

lighting. DOE estimated the daily electrical load of lighting as 1.392 kWh/day for one lamp 

using the method explained in section 5.6.7.1. DOE then summed the energy use of the lamp 

 EE-2006-STD-0126 COMMENT 23.2
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and compressor for each VCT equipment class to get the total daily energy consumption of a 

zero-length case for each class. These figures became the offset factors for the various VCT 

equipment classes. Table 5.8.1 Offset Factors shows the offset factors for the 15 primary 

equipment classes. 

Table 5.8.1 Offset Factors 

Equipment 

Class 

Offset 

Factor 

(kWh/day)

VCT.RC.L 2.61 

VOP.RC.M 4.07 

SVO.RC.M 3.18 

HZO.RC.L 6.88 

HZO.RC.M 2.88 

VCT.RC.M 1.95 

VOP.RC.L 6.85 

SOC.RC.M 0.11 

VOP.SC.M 4.71 

SVO.SC.M 4.59 

HZO.SC.L 7.08 

HZO.SC.M 5.55 

HCT.SC.I 0.43 

VCT.SC.I 3.29 

VCS.SC.I 0.88 

5.9 EXTENSION OF STANDARDS 

DOE did not analyze all covered equipment classes, but focused its analysis on 15 highshipment equipment classes (Table 5.2.2). DOE developed an extension approach to apply the 

standards developed for these 15 “primary” classes to the remaining 23 “secondary” classes. 

This approach involves extension multipliers developed with the 15 primary results and a set of 

focused matched-pair analyses. In addition, standards for certain primary equipment classes can 

be directly applied to other similar secondary equipment classes. This section explains each 

aspect of this approach. 

In the NOPR, trial standard levels are presented for each of the 15 primary equipment 

classes in the form of a standard equation. This standard equation consists of a size-dependent 

multiplier (slope) and an offset factor (section 5.8). The extension multipliers are applied to the 

slopes and offset factors of the primary standard equations (Figure 5.9.1). In this illustration, a 

standard is multiplied by an extension factor greater than one, for example in the case of 

extending a standard from a low-temperature class to an ice-cream-temperature class. 

 EE-2006-STD-0126 COMMENT 23.2
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Figure 5.9.1 Illustration of Extension of Standard Level 

5.9.1 Extension Multipliers 

DOE examined extending standards using the 15 primary equipment classes developed in 

the engineering analysis. Using the TDA-normalized baseline CDEC values, several trends are 

apparent for certain sub-groups of equipment. DOE examined several related pairs of equipment 

classes to develop extension multipliers. 

First, DOE examined the CDEC/TDA relationship between remote and self-contained 

medium-temperature equipment without doors (Table 5.9.1). There is reasonable agreement 

across equipment families among medium-temperature open equipment, with an average 

multiplier of 2.51 between remote and self-contained equipment. The differences between 

remote and self-contained equipment are similar for VOP, SVO, and HZO equipment. In 

addition to the inclusion of a self-contained condensing unit, which is less efficient than remote 

condensing systems, self-contained open equipment must have provisions for dealing with 

defrost meltwater. Because self-contained equipment is designed to be mobile, defrost meltwater 

must be collected in a drain pan and evaporated using electric-resistance heating. This feature 

adds considerable energy use to open self-contained equipment. The 2.51 multiplier is also 

applicable to low- and ice-cream-temperature equipment without doors. The differences in 

design are similar for low-temperature and ice-cream-temperature equipment, consisting of a 

self-contained condensing unit and the addition of a defrost meltwater evaporation system. 

Thus, the 2.51 multiplier is applicable to the following standard extensions: 

• VOP.RC.L to VOP.SC.L 

• SVO.RC.L to SVO.SC.L 

• VOP.RC.I to VOP.SC.I 

• SVO.RC.I to SVO.SC.I 

• HZO.RC.I to HZO.SC.I 

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Table 5.9.1 Extension Multipliers for Remote and Self-Contained Equipment 

Without Doors 

Relationship CDEC/TDA Multiplier 

VOP.RC.M to VOP.SC.M 2.431 

SVO.RC.M to SVO.SC.M 2.376 

HZO.RC.M to HZO.SC.M 2.712 

DOE next examined the CDEC/TDA relationship between low-temperature and icecream-temperature remote equipment using a focused matched-pair analysis. The focused 

matched-pair analysis methodology was described in detail in the ANOPR TSD, and establishes 

a correlation between rating temperature levels and CDEC/TDA, using data collected from 

manufacturer specification sheets. DOE quantified the differences in energy consumption for 

matched pairs of equipment classes that are very similar in features and dimensions, but have 

different operating temperatures. Pairs of units at low- and ice-cream-temperatures were 

selected from several different manufacturers for comparison. DOE selected identical units from 

a given manufacturer designed to operate at multiple temperatures to isolate operating 

temperature as the only variable. 

The matched-pair results show that VCT.RC.I units (at -15°F) have on average 

CDEC/TDA values that are 1.17 times higher than comparable VCT.RC.L units. The 1.17 

multiplier is also applicable to other similar equipment types with doors. Differences in design 

consist of a lower operating temperature (resulting in a lower compressor EER) and higher 

defrost and anti-sweat heater power. Thus, the 1.17 multiplier is applicable to the following 

standard extensions: 

• SOC.RC.L to SOC.RC.I 

• HCT.RC.L to HCT.RC.I 

The matched-pair results further show that HZO.RC.I units (at -15°F) have on average 

CDEC/TDA values that are 1.27 times higher than comparable HZO.RC.L units. The 1.27 

multiplier is also applicable to other similar equipment types without doors. Differences in 

design consist of a lower operating temperature (resulting in a lower compressor EER) and 

higher defrost and anti-sweat heater power. Thus, the 1.27 multiplier is applicable to the 

following standard extensions: 

• VOP.RC.L to VOP.RC.I 

• SVO.RC.L to SVO.RC.I 

• VOP.SC.L to VOP.SC.I 

• SVO.SC.L to SVO.SC.I 

• HZO.SC.L to HZO.SC.I 

DOE next examined the CDEC/TDA relationship between remote and self-contained icecream-temperature equipment with transparent doors. To make this comparison, DOE used the 

matched-pair results to estimate the baseline CDEC/TDA values for VCT.RC.I equipment, and 

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compared the results to VCT.SC.I equipment. The comparison showed that CDEC/TDA values 

for VCT.SC.I equipment are 1.40 times higher than VCT.RC.I equipment. DOE understands 

that this difference in energy use is due to the differences in efficiency of the self-contained 

condensing unit, as well as the addition of defrost meltwater evaporation systems. However, in 

contrast to open equipment, equipment with transparent doors is subject to a much lower 

infiltration load, and thus a lower melt water evaporation requirement. This leads to a lower 

multiplier than was seen for open equipment. The 1.40 multiplier can be applied to the following 

standard extensions: 

• SOC.RC.I to SOC.SC.I 

• HCT.RC.I to HCT.SC.I 

• VCS.RC.I to VCS.SC.I 

• HCS.RC.I to HCS.SC.I 

Finally, DOE examined the relationship between medium- and low-temperature remote 

equipment with transparent doors. Both the VCT.RC.M and VCT.RC.L equipment classes were 

directly examined in the engineering analysis. Using the engineering results, the comparison 

showed that CDEC/TDA values for VCT.RC.L equipment are 2.10 times higher than 

VCT.RC.M equipment. This difference is due to the higher defrost heater power and anti-sweat 

heater power requirements in low-temperature equipment. The 2.10 multiplier can be applied to 

the standard extension from HCT.RC.M to HCT.RC.L. 

Using these extension factors, DOE can extend standards to the 23 secondary equipment 

classes, as illustrated in Table 5.9.2. Baseline CDEC/TDA values for the 15 primary equipment 

classes are represented by the letters a through o (in bold for the 15 primary classes) for 

simplicity, multiplied or divided by the appropriate extension values. Note that the SVO.RC.L 

baseline CDEC/TDA value is identified as “a,” which is the same as the baseline CDEC/TDA 

value for VOP.RC.L. The baseline CDEC/TDA values for VOP.RC.M (b) and SVO.RC.M (d) 

are equal, and additionally the CDEC/TDA levels above the baseline are very similar (see 

detailed cost-efficiency results in Appendix B). The similarities in these two mediumtemperature equipment classes would extend to the respective low-temperature versions. Also 

note that the baseline CDEC/TDA value for the HCS.SC.I equipment class is identified as the 

letter “o,” which is the same value for VCS.SC.I. The orientation has little effect on energy 

consumption for equipment with solid doors, and standards for all corresponding equipment 

classes within the VCS and HCS families should be equivalent. 

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Table 5.9.2 Extension Multipliers by Equipment Class 

 RC SC 

 I L M I L M 

VOP 1.27a a b 1.27(2.51c) 2.51c c 

SVO 1.27a a d 1.27(2.51e) 2.51e e 

Open 

HZO 1.27f f g 1.27h h i 

SOC 1.17(2.10j) 2.10j j 1.40(1.17(2.10j)) 

VCT 1.17k k l m 

HCT n/1.40 (n/1.40)/1.17 ((n/1.40)/1.17)/2.10 n 

Closed 

VCS o/1.40 (o/1.40)/1.17 ((o/1.40)/1.17)/2.10 O 

HCS o/1.40 (o/1.40)/1.17 ((o/1.40)/1.17)/2.10 o 

5.10 SENSITIVITY ANALYSES 

DOE conducted two sensitivity analyses. The first examined the sensitivity of the costefficiency curves to material prices. The second examined the sensitivity of standards to 

alternative refrigerants. 

5.10.1 Material Price Sensitivity 

DOE conducted a sensitivity analysis on material prices to examine the effect of spikes in 

commodity prices that the industry has experienced over the past few years. The analysis 

compares the 5-year average prices for 2002-2006 (described in section 5.4.3) with the 5-year 

high price for the same period (2006 is the year with the highest material prices during that 5-

year period). The results of this sensitivity analysis are presented in Figure 5.10.1 for the 

VOP.RC.M equipment class, which has the highest shipment volume of all analyzed equipment 

classes. Shown for comparison is the industry-supplied data for the VOP.RC.M equipment class. 

In addition to adding about 15 percent to the overall cost of the equipment, the large 

increase in copper prices dramatically raises the cost of the evaporator coil (roughly 50 percent 

for both the baseline and enhanced evaporator coil). This increase in coil cost reduces the costeffectiveness of this design option, which can be seen as a change in the slope of the costefficiency curve between the third and fourth design option levels above the baseline. For this 

equipment class, the 5-year average prices produce an analytically derived curve that more 

closely matches the industry-supplied curve. Based on the assumption that the overall case cost 

would increase by roughly 15 percent for other equipment classes, the 5-year average prices 

would also provide a closer match than the 5-year high prices for the other industry-supplied 

curves (Figure 5.7.1, Figure 5.7.3, and Figure 5.7.4). 

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Figure 5.10.1 Material Price Sensitivity for the VOP.RC.M Equipment Class

5.10.2 Alternative Refrigerants 

In conducting an engineering analysis, DOE must consider the effects of regulatory 

changes outside DOE’s statutory energy conservation standards rulemaking process that can 

affect the manufacturers of the covered equipment. Some of these changes can also affect the 

energy efficiency or energy consumption of the covered equipment. DOE identified such 

external engineering issues that could affect the engineering analysis. These issues are closely 

related to the cumulative regulatory burden assessment that DOE carried out as part of the 

manufacturer impact analysis. 

Due to the phase-out of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons 

(HCFCs), the commercial refrigeration industry must transition to non-ozone-depleting 

refrigerants. As a result, the refrigeration industry is transitioning to hydrofluorocarbon-based 

(HFC-based) refrigerants in its equipment. For the commercial refrigeration equipment covered 

in this rulemaking, much of the industry has already been using HFC-based refrigerants for both 

remote condensing and self-contained equipment. Therefore, DOE considered the effects of 

HFC-based refrigerants from the outset by using HFC refrigerants in its analyses. For remote 

condensing equipment, the compressor efficiency values used in its analysis are based on ARI 

1200, which uses an HFC-based compressor rack with R-404a refrigerant. Likewise for selfcontained equipment, DOE’s analysis uses R-134a and R-404a, both HFC-based refrigerants. 

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5.11 RESULTS 

DOE presents more detailed results and supporting data for the engineering analysis in 

Appendix B of this TSD.

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REFERENCES 

1

 American Metals Market. 2007. (Last accessed July 11, 2007.) http://www.amm.com/ 

The July 11, 2007, material from this website is available in Docket # EE-2006-STD0126. For more information, contact Brenda Edwards-Jones at (202) 586-2945. 

2

 U.S. Department of Labor, Bureau of Labor Statistics. Producer Price Indices. 2007. 

(Last accessed June 28, 2007.) http://www.bls.gov/ppi/ The June 28, 2007, material 

from this website is available in Docket #EE-2006-STD-0126. For more information, 

contact Brenda Edwards-Jones at (202) 586-2945. 

3

 U.S. Department of Commerce, Bureau Economic Analysis, Gross Domestic Product 

Implicit Price Deflator. 2007. (Last accessed June 28, 2007.) 

<https://bea.gov/bea/dn/nipaweb/TableView.asp#Mid> The June 28, 2007 material 

from this website is available in Docket #EE-2006-STD-0126. For more information, 

contact Brenda Edwards-Jones at (202) 586-2945. 

4

 David H. Walker, Ramin T. Farmarzi, Van D. Baxter, Investigation of Energy-Efficient 

Supermarket Display Cases. 2004. Oak Ridge National Laboratory: Oak Ridge, TN. 

Report No. TM-292-2004. 

5

 Lawrence Berkley National Laboratory. Window 5.0. 2007. (Last accessed June 26, 

2007.) http://windows.lbl.gov/software/window/window.html The June 26, 2007 

material from this website is available in Docket #EE-2006-STD-0126. For more 

information, contact Brenda Edwards-Jones at (202) 586-2945. 

6

 Refrigeration and Thermal Test Center. Personal communication. Southern California 

Edison. March 29, 2007. 

7

 ANSI/ASHRAE. Standard 72-2005: Method of Testing Commercial Refrigerators and 

Freezers. 2005. 

8

 Electric Power Research Institute. Supermarket Simulation Tool v3.0. 2007. 

9

 R. Faramarzi. Efficient Display Case Refrigeration. In ASHRAE Journal. November 

1999. 

10 P. D'Agaro, G. Cortella, G. Croce, Two- and Three-Dimensional CFD Applied to 

Vertical Display Cabinet Simulation, Int. J Refrigeration, Vol. 29, 2, pp. 178-190, 

2005. 

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