CHAPTER 5. ENGINEERING ANALYSIS 

TABLE OF CONTENTS 

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

5.2 METHODOLOGY OVERVIEW...................................................................................... 5-1
 

5.3 COST MODEL.................................................................................................................. 5-2
 

5.3.1 Cost Model Overview............................................................................................. 5-2
 

5.3.2 Structure of the Cost Model Spreadsheet ................................................................ 5-4
 

5.3.2.1 Material Prices ......................................................................................... 5-4
 

5.3.2.2 Fabricated Parts and Purchased Parts ...................................................... 5-4
 

5.3.2.3 Factory Parameters................................................................................... 5-7
 

5.3.3 Downstream Analyses ............................................................................................ 5-9
 

5.3.4 Manufacturer Selling Price Estimates..................................................................... 5-9
 

5.4 ENERGY CONSUMPTION MODEL ............................................................................ 5-10
 

5.4.1 Screened-In Technologies ..................................................................................... 5-10
 

5.4.1.1 Screened in Technologies for Envelopes............................................... 5-10
 

5.4.1.2 Screened in Technologies for Refrigeration Systems ............................ 5-11
 

5.4.2 Screened-In Technologies Not Considered in the Engineering Analysis............. 5-11
 

5.4.2.1 Ambient Subcooling .............................................................................. 5-11
 

5.4.2.2 High Efficiency Two-speed and Variable-speed Compressors ............. 5-12
 

5.4.3 Design Options...................................................................................................... 5-12
 

5.4.4 Details for Envelope Design Options ................................................................... 5-16
 

5.4.4.1 Improved Wall, Ceiling, and Floor Insulation ....................................... 5-18
 

5.4.4.2 Improved Door Gaskets and Panel Interface Systems ........................... 5-23
 

5.4.4.3 Electronic Lighting Ballasts and High-Efficiency Lighting .................. 5-25
 

5.4.4.4 Occupancy Sensors and Automatic Door Opening and Closing Systems. 5­

27
 

5.4.4.5 Air Curtains and Strip Curtains.............................................................. 5-27
 

5.4.4.6 Vestibule Entryways .............................................................................. 5-29
 

5.4.4.7 Display and Window Glass System Insulation Enhancement ............... 5-30
 

5.4.4.8 Anti-sweat Heater Controls and No Anti-sweat Systems...................... 5-32
 

5.4.5 Details for Refrigeration System Design Options ................................................ 5-33
 

5.4.5.1 High-Efficiency Scroll Compressors ..................................................... 5-34
 

5.4.5.2 Condenser Coil....................................................................................... 5-35
 

5.4.5.3 Condenser Fan Motors........................................................................... 5-36
 

5.4.5.4 Evaporator and Condenser Fan Blades.................................................. 5-36
 

5.4.5.5 Evaporator Coil...................................................................................... 5-37
 

5.4.5.6 Evaporator Fan Control.......................................................................... 5-38
 

5.4.5.7 Floating Head Pressure .......................................................................... 5-39
 

5.4.5.8 Defrost Controls..................................................................................... 5-39
 

5.4.6 Baseline Specifications ......................................................................................... 5-40
 

5.4.7 Non-Numerical Assumptions................................................................................ 5-45
 

5.4.7.1 Assumptions Concerning the Envelope Energy Calculations ............... 5-45
 

5.4.7.2 Assumptions Concerning the Refrigeration Energy Consumption........ 5-46
 

5.4.8 Numerical Constants and Assumptions ................................................................ 5-47
 

5-i 
 

5.4.9 Model Components: Envelope.............................................................................. 5-49
 

5.4.9.1 Heat Conduction Load ........................................................................... 5-50
 

5.4.9.2 Energy Efficiency Ratio (EER) ............................................................. 5-50
 

5.4.9.3 Infiltration Load: Steady-State ............................................................... 5-51
 

5.4.9.4 Infiltration Load: Door Opening ............................................................ 5-51
 

5.4.9.5 Anti-Sweat and Other Heater Wire Electrical Load .............................. 5-51
 

5.4.9.6 Lighting Electrical Load ........................................................................ 5-52
 

5.4.9.7 Other Electrical Devices ........................................................................ 5-52
 

5.4.9.8 Additional Heat Load Due to Electrical Device Waste Heat................. 5-52
 

5.4.10Model Components: Refrigeration ....................................................................... 5-52
 

5.4.10.1 Net Capacity........................................................................................... 5-54
 

5.4.10.2 On-Cycle System Power........................................................................ 5-54
 

5.4.10.3 Load Factors........................................................................................... 5-54
 

5.5 COST-EFFICIENCY CURVES...................................................................................... 5-56
 

5.5.1 Envelope Cost-Efficiency Curves......................................................................... 5-57
 

5.5.2 Refrigeration Cost-Efficiency Curves................................................................... 5-69
 

LIST OF TABLES 

Table 5.3.1 Cost Model Output Classifications.......................................................................... 5-2
 

Table 5.3.2 Purchased WICF Components................................................................................. 5-6
 

Table 5.3.3 Factory Parameter Assumptions, Refrigeration Equipment .................................... 5-8
 

Table 5.3.4 Factory Parameter Assumptions, Envelope ............................................................. 5-8
 

Table 5.4.1 Baseline Design Options for Envelope, Non-Display ........................................... 5-13
 

Table 5.4.2 Baseline Design Options for Envelope, Display ................................................... 5-14
 

Table 5.4.3 Baseline Design Options for Refrigeration Systems ............................................. 5-15
 

Table 5.4.4 Design Option Codes and Descriptions for Envelopes.......................................... 5-17
 

Table 5.4.5 Details for “Wall and Ceiling Insulation Thickness” Design Option .................... 5-18
 

Table 5.4.6 Details for “Wall and Ceiling Insulation Thickness” Design Option Cont. .......... 5-18
 

Table 5.4.7 Details for “Wall and Ceiling Insulation Thickness” Design Option Cont. .......... 5-19
 

Table 5.4.8 Total Shipping Cost for Product Classes and Thicknesses Considered................. 5-19
 

Table 5.4.9 Details for “Floor Insulation” Design Option, FEA Results ................................. 5-20
 

Table 5.4.10 Details for “Floor Insulation” Design Option, FEA Inputs ................................. 5-20
 

Table 5.4.11 Details for “Floor Insulation” Design Option, Cost ............................................ 5-21
 

Table 5.4.12 Details for “Insulation Materials A” Design Option ........................................... 5-21
 

Table 5.4.13 Details for “Insulation Materials B” Design Option ............................................ 5-22
 

Table 5.4.14 Details for “Insulation Materials B” Design Option, Continued ......................... 5-22
 

Table 5.4.15 Details for “Insulation Materials B” Design Option, Engineering Cost .............. 5-22
 

Table 5.4.16 Details for “Insulation Materials B” Labor Cost ................................................. 5-23
 

Table 5.4.17 Details for “Sealant Enhancement” Design Option ............................................. 5-24
 

Table 5.4.18 Details for “Sealant Enhancement” Design Option, Cont. .................................. 5-24
 

Table 5.4.19 Details for “Sealant Enhancement” Design Option, Engineering Cost ............... 5-25
 

Table 5.4.20 Details for “Sealant Enhancement” Design Option, Labor Cost ......................... 5-25
 

Table 5.4.21 Details for “Sealant Enhancement” Design Option, Material Cost..................... 5-25
 

Table 5.4.22 Details for “Lighting: Display” Design Option, Performance Data .................... 5-26
 

Table 5.4.23 Details for “Lighting: Display” Design Option, Performance Data Cont. .......... 5-26
 

5-ii 
Table 5.4.24 Details for “Lighting: Display” Design Option, Cost Data ................................. 5-26
 

Table 5.4.25 Details for “Lighting: Display” Design Option, Cost Data Cont ........................ 5-26
 

Table 5.4.26 Details for “Lighting: Non-Display” Design Option ........................................... 5-27
 

Table 5.4.27 Details for “Control Systems” Design Option ..................................................... 5-27
 

Table 5.4.28 Details for “Active Infiltration Reduction Devices” Design Option ................... 5-28
 

Table 5.4.29 Details for “Passive Infiltration Reduction Devices” Design Option .................. 5-29
 

Table 5.4.30 Details for “Door Systems” Design Option ......................................................... 5-30
 

Table 5.4.31 Details for “Display Door Enhancement” Design Option ................................... 5-31
 

Table 5.4.32 Details for “Display Door Enhancement” Design Option, Window 5.2 ............. 5-31
 

Table 5.4.33 Details for “Display Door Enhancement” Design Option, Window 5.2, Coolers ...... 

............................................................................................................................. 5-31
 

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

Table 5.4.34 Details for “Display Door Enhancement” Design Option, Window 5.2, Freezers..... 

Table 5.4.35 Details for “Display Door Enhancement” Design Option, Gas Fill Cost............ 5-32
 

Table 5.4.36 Details for “Anti-Sweat Heaters” Design Option................................................ 5-33
 

Table 5.4.37 Design Option Codes and Descriptions for Refrigeration Systems ..................... 5-34
 

Table 5.4.38 Details for "High-Efficiency Scroll Compressor" Design Option ....................... 5-35
 

Table 5.4.39 Details for "Condenser Coil" Design Option ....................................................... 5-35
 

Table 5.4.40 Details for "Condenser Coil" Design Option, Continued.................................... 5-36
 

Table 5.4.41 Details for "Condenser Fan Motor" Design Option ............................................. 5-36
 

Table 5.4.42 Details for “High Efficiency Fan Blades – Evaporator” Design Option ............. 5-37
 

Table 5.4.43 Details for “High Efficiency Fan Blades – Condenser” Design Option .............. 5-37
 

Table 5.4.44 Details for "Evaporator Coil" Design Option ...................................................... 5-38
 

Table 5.4.45 Details for "Evaporator Coil" Design Option, Continued ................................... 5-38
 

Table 5.4.46 Details for “Evaporator Fan Control” Design Option ......................................... 5-39
 

Table 5.4.47 Details for “Floating Head Pressure” Design Option .......................................... 5-39
 

Table 5.4.48 Details for “Defrost Controls” Design Option ..................................................... 5-40
 

Table 5.4.49 Baseline Specifications for Envelopes, Coolers .................................................. 5-41
 

Table 5.4.50 Baseline Specifications for Envelopes, Freezers ................................................. 5-42
 

Table 5.4.51 Baseline Specifications for Refrigeration Systems, Medium Temperature......... 5-43
 

Table 5.4.52 Baseline Specifications for Refrigeration Systems, Low Temperature............... 5-44
 

Table 5.4.53 Envelope Assumptions ........................................................................................ 5-48
 

Table 5.4.54 Refrigeration System Assumptions Associated with Defrost.............................. 5-49
 

Table 5.4.55 Refrigeration System Baseline TD Assumptions ................................................ 5-49
 

Table 5.5.1 Cost-Efficiency Data for the ND.C. Small Equipment Class................................ 5-57
 

Table 5.5.2 Cost-Efficiency Data for the ND.C. Medium Equipment Class ............................ 5-58
 

Table 5.5.3 Cost-Efficiency Data for the ND.C. Large Equipment Class ................................ 5-59
 

Table 5.5.4 Cost-Efficiency Data for the D.C. Small Equipment Class ................................... 5-60
 

Table 5.5.5 Cost-Efficiency Data for the D.C. Medium Equipment Class............................... 5-61
 

Table 5.5.6 Cost-Efficiency Data for the D.C. Large Equipment Class ................................... 5-62
 

Table 5.5.7 Cost-Efficiency Data for the ND.F. Small Equipment Class ................................ 5-63
 

Table 5.5.8 Cost-Efficiency Data for the ND.F. Medium Equipment Class ............................ 5-64
 

Table 5.5.9 Cost-Efficiency Data for the ND.F. Large Equipment Class ................................ 5-65
 

Table 5.5.10 Cost-Efficiency Data for the D.F. Small Equipment Class ................................. 5-66
 

Table 5.5.11 Cost-Efficiency Data for the D.F. Medium Equipment Class ............................. 5-67
 

Table 5.5.12 Cost-Efficiency Data for the D.F. Large Equipment Class ................................. 5-68
 

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Table 5.5.13 Cost-Efficiency Data for the DC.M.I Equipment Class (Small) ......................... 5-69
 

Table 5.5.14 Cost-Efficiency Data for the DC.M.I Equipment Class (Large) ......................... 5-70
 

Table 5.5.15 Cost-Efficiency Data for the DC.M.O Equipment Class (Small) ........................ 5-71
 

Table 5.5.16 Cost-Efficiency Data for the DC.M.O Equipment Class (Large)........................ 5-72
 

Table 5.5.17 Cost-Efficiency Data for the MC.M.I Equipment Class (Small) ......................... 5-73
 

Table 5.5.18 Cost-Efficiency Data for the MC.M.I Equipment Class (Large)......................... 5-74
 

Table 5.5.19 Cost-Efficiency Data for the DC.L.I Equipment Class (Small) .......................... 5-75
 

Table 5.5.20 Cost-Efficiency Data for the DC.L.I Equipment Class (Large) .......................... 5-76
 

Table 5.5.21 Cost-Efficiency Data for the DC.L.O Equipment Class (Small) ......................... 5-77
 

Table 5.5.22 Cost-Efficiency Data for the DC.L.O Equipment Class (Large)......................... 5-78
 

Table 5.5.23 Cost-Efficiency Data for the MC.L.I Equipment Class (Small) .......................... 5-79
 

Table 5.5.24 Cost-Efficiency Data for the MC.L.I Equipment Class (Large) .......................... 5-80
 

LIST OF FIGURES 

Figure 5.3.1 Production Flow in BOM ....................................................................................... 5-3
 

Figure 5.3.2 Components of Manufacturer Selling Price ......................................................... 5-10
 

Figure 5.4.1 Panel Tongue and Groove Construction............................................................... 5-23
 

Figure 5.4.2 Overhead View of Walk-In and Vestibule Entryway........................................... 5-30
 

Figure 5.4.3 Examples of Standard Fan Blades,....................................................................... 5-37
 

Figure 5.4.4 Examples of High Efficiency Fan Blades, ........................................................... 5-37
 

Figure 5.4.5 Overview of Envelope Engineering Analysis Calculations ................................. 5-50
 

Figure 5.4.6 Energy Consumption Model for Dedicated Condensing Systems ....................... 5-53
 

Figure 5.4.7 Energy Consumption Model for Unit Coolers Connected to Multiplex Condensing
 

Systems ................................................................................................................ 5-56
 

Figure 5.5.1 Cost-Efficiency Curve for the ND.C. Equipment Class [Small, Number of Doors: 

Display, Passage, and Freight (0,1,0)]................................................................. 5-57
 

Figure 5.5.2 Cost-Efficiency Curve for the ND.C. Equipment Class [Medium, Number of Doors: 

Display, Passage, and Freight (0,1,1)]................................................................. 5-58
 

Figure 5.5.3 Cost-Efficiency Curve for the ND.C. Equipment Class [Large, Number of Doors: 

Display, Passage, and Freight (0,2,1)]................................................................. 5-59
 

Figure 5.5.4 Cost-Efficiency Curve for the D.C. Equipment Class [Small, Number of Doors: 

Display, Passage, and Freight (3,1,0)]................................................................. 5-60
 

Figure 5.5.5 Cost-Efficiency Curve for the D.C. Equipment Class [Medium, Number of Doors: 

Display, Passage, and Freight (8,1,0)]................................................................. 5-61
 

Figure 5.5.6 Cost-Efficiency Curve for the D.C. Equipment Class [Large, Number of Doors: 

Display, Passage, and Freight (50,2,0)]............................................................... 5-62
 

Figure 5.5.7 Cost-Efficiency Curve for the ND.F. Equipment Class [Small, Number of Doors: 

Display, Passage, and Freight (0,1,0)]................................................................. 5-63
 

Figure 5.5.8 Cost-Efficiency Curve for the ND.F. Equipment Class [Medium, Number of Doors: 

Display, Passage, and Freight (0,1,1)]................................................................. 5-64
 

Figure 5.5.9 Cost-Efficiency Curve for the ND.F. Equipment Class [Large, Number of Doors: 

Display, Passage, and Freight (0,2,1)]................................................................. 5-65
 

Figure 5.5.10 Cost-Efficiency Curve for the D.F. Equipment Class [Small, Number of Doors: 

Display, Passage, and Freight (3,1,0)]................................................................. 5-66
 

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Figure 5.5.11 Cost-Efficiency Curve for the D.F. Equipment Class [Medium, Number of Doors: 

Display, Passage, and Freight (8,1,0)]................................................................. 5-67
 

Figure 5.5.12 Cost-Efficiency Curve for the D.F. Equipment Class [Large, Number of Doors: 

Display, Passage, and Freight (50,2,0)]............................................................... 5-68
 

Figure 5.5.13 Cost-Efficiency Curve for the DC.M.I Equipment Class (Small) ...................... 5-69
 

Figure 5.5.14 Cost-Efficiency Curve for the DC.M.I Equipment Class (Large)...................... 5-70
 

Figure 5.5.15 Cost-Efficiency Curve for the DC.M.O Equipment Class (Small) .................... 5-71
 

Figure 5.5.16 Cost-Efficiency Curve for the DC.M.O Equipment Class (Large) .................... 5-72
 

Figure 5.5.17 Cost-Efficiency Curve for the MC.M.I Equipment Class (Small) ..................... 5-73
 

Figure 5.5.18 Cost-Efficiency Curve for the MC.M.I Equipment Class (Large) ..................... 5-74
 

Figure 5.5.19 Cost-Efficiency Curve for the DC.L.I Equipment Class (Small) ....................... 5-75
 

Figure 5.5.20 Cost-Efficiency Curve for the DC.L.I Equipment Class (Large)....................... 5-76
 

Figure 5.5.21 Cost-Efficiency Curve for the DC.L.O Equipment Class (Small) ..................... 5-77
 

Figure 5.5.22 Cost-Efficiency Curve for the DC.L.O Equipment Class (Large) ..................... 5-78
 

Figure 5.5.23 Cost-Efficiency Curve for the MC.L.I Equipment Class (Small) ...................... 5-79
 

Figure 5.5.24 Cost-Efficiency Curve for the MC.L.I Equipment Class (Large) ...................... 5-80
 

5-v 
 

 

CHAPTER 5. ENGINEERING ANALYSIS
 

5.1 INTRODUCTION 

The engineering analysis establishes the relationship between manufacturer selling price 

(MSP) and energy consumption for the walk-in coolers and freezers covered in this rulemaking. 

The cost-energy consumption relationship serves as the basis for the cost/benefit calculations for 

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 baseline models, 

then converts each MPC to MSP by applying a multiplier to determine the manufacturer markup. 

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 in the preliminary 

TSD) and technology options from the screening analysis (chapter 4 in the preliminary TSD). 

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-energy consumption curves and a manufacturer markup multiplier used 

to convert MPC to MSP. In the subsequent markups analysis (chapter 6 in the preliminary TSD), 

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

markups. After applying these markups, the data serve as inputs to the energy use analysis 

(chapter 7 in the preliminary TSD) and the life cycle cost and payback period analyses (chapter 8 

in the preliminary TSD). 

In this chapter, DOE discusses representative baseline units, methodology used to 

develop MPC, markups to MSP, sensitivity to material prices, methodology used to estimate 

energy consumption, cost-energy consumption curves, normalization of energy consumption 

metrics, and design options. 

5.2 METHODOLOGY OVERVIEW 

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

this rulemaking, DOE is adopting a design-option approach, which calculates the incremental 

costs of adding specific design options to a baseline model. As discussed in Chapter 2, DOE is 

considering the envelope and the refrigeration system separately. Consequently, DOE developed 

separate engineering curves for envelopes and refrigeration systems while using the same general 

cost and energy consumption models for each component. Furthermore, for each equipment class 

of both envelopes and refrigeration systems, DOE analyzed different size equipment to assess 

how energy use varies with size. DOE specified a small- and large-capacity unit of each class for 

the refrigeration system analysis, and a small, medium, and large size envelope of each class for 

the envelope analysis. A baseline unit was specified for each equipment class based on 

equipment offerings currently on the market. See chapter 3 of the preliminary TSD for a detailed 

description of the equipment classes and section 5.4.6 below for additional detail on the different 

size machines analyzed. 

5-1 
 

 

For each equipment class and size, DOE developed both an envelope cost and a 

refrigeration system cost using a manufacturing cost model. DOE also developed an envelope 

energy consumption and a refrigeration system energy consumption using an energy 

consumption model. DOE combined the cost analyses and energy consumption analyses to 

obtain a relationship between cost and energy consumption, expressed as a plot of cost vs. 

energy consumption for each design option, for refrigeration systems and envelopes. These plots 

appear in section 5.5. 

5.3 COST MODEL 

The cost model is the first of two key analytical models used in constructing costefficiency curves. A cost model was used to estimate the baseline cost of an envelope and a 

refrigeration system of a walk-in cooler or freezer. This cost model was adapted from the cost 

models for beverage vending machines and commercial refrigeration equipment, as walk-ins 

share many of the same general components and features. The cost model was significantly 

modified to add features that are unique to walk-in envelopes and refrigeration systems, such as 

foam insulation and large fan assemblies. DOE also modified the model for walk-in coolers and 

freezers using input from stakeholders on unit MPC estimates and assumptions to confirm 

accuracy. 

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

categories: 

Table 5.3.1 Cost Model Output Classifications 

Major Category Sub-Category Description 

Material Costs Direct Raw materials (i.e. coils of sheet metal) and purchased parts (i.e. fan 

motors, compressors, etc.) 

Indirect Welding rods, die oil, release media 

Manufacturing 

Labor 

Assembly Parts / unit assembly on manufacturing line 

Fabrication Conversion of raw material into parts ready for assembly 

Indirect Fraction of overall labor not associated directly with product 

manufacturing, i.e. forklift drivers, quality control, for example. 

Supervisory Fraction of above labor, is paid a higher wage 

Depreciation 

Equipment, 

Conveyor, Building Straight line depreciation over expected life. 

Tooling Cost is allocated on a per-use basis or obsolescence, whichever is 

shorter. 

Other Overhead 

Utilities A fixed fraction of all material costs meant to cover electricity and 

other utility costs. 

Maintenance Based on installed equipment and tooling investment. 

Property Tax and 

Insurance A fixed fraction based on total unit costs. 

The cost model analysis created cost estimates for each of the walk-in coolers and 

freezers analyzed. The cost model uses specific assumptions to provide cost estimates, and the 

following sections describe these assumptions. 

5.3.1 Cost Model Overview 

5-2 
 

 

 

 

 

This section provides a general overview of how the cost model works. The first step in 

the cost model analysis is to create a structured bill of materials (BOM) as a basis for all future 

cost analysis. Typically, products or equipment are purchased and disassembled piece-by-piece 

until no parts are left over. Every component is cataloged, analyzed, and photographed. Items are 

classified by sub-assembly, function, and any fabrication and assembly operations that DOE 

estimates the manufacturer to perform in their facility. For example, DOE distinguishes whether 

parts are purchased (and hence are limited to assembly) or whether the components are 

fabricated on site (requiring equipment, labor, etc. prior to integration into the final product). 

DOE consults a wide range of industry sources for purchased parts and raw materials to help 

estimate total material costs. Additionally, DOE conducts site visits to confirm which parts are 

purchased versus being fabricated on-site, and why. 

Purchased Parts 

Inventory 

Fabrication 

Processes Assembly, 

Packaging, 

Distribution 

Raw 

Materials 

Ready-to-Assemble 

Parts 

Figure 5.3.1 Production Flow in BOM 

For the WICF analysis, DOE did not conduct a tear-down analysis based on equipment available 

for purchase due to the size and complexity of purchasing entire walk-in cooler systems. 

Instead, DOE visited multiple manufacturing facilities to observe variability in manufacturing 

techniques, noting materials, purchased parts, and labor used. Additionally, DOE conducted 

interviews with manufacturers to ensure the accuracy of the WICF model’s methodology and 

pricing. 

When appropriate, a supplementary method, called a catalogue teardown, was used to 

supplement the already-gathered data. A catalogue teardown is based on published manufacturer 

product literature and supplementary component data. Typically, it uses a similar product that 

was torn down as a starting point, and differences in construction, purchased parts, etc. are then 

accounted for. A catalog teardown thus serves the purpose of greatly expanding the number of 

units and capacity ranges under consideration without the significant expense attached to 

purchasing a very wide range of equipment. 

Besides noting all material, labor, and overhead costs, the cost model also estimates the 

facility requirements for a given production volume. Thus, the bill of materials (BOM) will 

generate detailed equipment, tooling, and space requirements for a given production volume. For 

this rulemaking, incoming and outgoing freight were accounted for since they have a significant 

impact on production and shipping costs due to the large physical volume of WICF panels. 

However, the outbound freight cost is not considered a manufacturing cost, but is added as part 

of the manufacturer selling price. DOE based assumptions about the sourcing of parts and inhouse fabrication on industry experience, information in trade publications, and discussions with 

manufacturers. 

5-3 
 

 

 

In sum, DOE assigned costs of labor, materials, and overhead to each part, whether 

purchased or produced in-house. DOE then aggregated single-part costs into major assemblies 

(e.g., panel assembly, door assemblies, condensing unit, evaporator unit, controls, and 

packaging), and summarized these costs in a spreadsheet. 

5.3.2 Structure of the Cost Model Spreadsheet 

Manufacturer practices and cost structure play an important role in estimating the final 

cost of the equipment. Depending on conditions in the marketplace regarding capital, labor, and 

other factors, a manufacturer will choose different approaches to manufacturing its products, 

ranging from outsourcing all production to being completely vertically integrated. DOE attempts 

to capture a representative view of industry economic and manufacturing conditions through its 

model, teardowns, and site visits. 

For this particular industry, DOE noted that manufacturers generally assembled panel 

systems with a mix of raw materials (i.e. converted sheet metal, foam, etc.) and purchased parts 

(i.e. fasteners, door hardware, cut-to-length seals, etc.). WICF refrigeration systems were 

generally purchased either as complete assemblies or modified in-house using purchased parts. 

For the raw materials being converted to ready-to-assemble parts, DOE estimated manufacturing 

process parameters, e.g., manufacturing equipment use and time for each item, the required 

initial material quantity, scrap, etc. to determine the value of each component. All parameters 

related to manufacture and assembly are then aggregated to determine facility requirements at 

various manufacturing scales and the final unit cost. 

The final equipment cost includes the material, labor, depreciation, and overhead costs 

associated with the manufacturing facility. The material costs include both raw materials and 

purchased part costs. The labor costs include fabrication, assembly, and indirect and overhead 

(burdened) labor rates. The depreciation costs include manufacturing equipment depreciation, 

tooling depreciation, and building depreciation. The overhead costs include indirect process 

costs, utilities, equipment and building maintenance, and rework. The following sections 

describe the cost model assumptions related to material prices, purchased parts and factory 

parameters. 

5.3.2.1 Material Prices 

DOE determined the cost of raw materials on the basis of manufacturer feedback, 

American Metals Market, i

 and Bureau of Labor Statistics Producer Price Index (PPI) data. ii To 

help address the impact of significant metal price fluctuations, metal price data is averaged over 

a five-year period. For non-metal materials, such as plastics, DOE uses the most current material 

prices it can obtain as opposed to a five-year average. 

5.3.2.2 Fabricated Parts and Purchased Parts 

DOE characterized parts based on whether manufacturers fabricated them in-house or 

purchased them from outside suppliers. For fabricated parts, DOE estimated initial raw material 

dimensions to account for scrap. For scrap materials that are recyclable, DOE assigned a scrap 

credit that is a fraction of the base material cost (i.e. high-cost rifled copper tubing is recycled on 

5-4 
 

the basis of the scrap value for plain copper). Non-recyclable materials incur a disposal cost for 

all scrap. 

For purchased parts, DOE estimated the purchase price for OEMs based on discussions 

with manufacturers and suppliers, expected shipment volumes, and industry experience. 

Whenever possible, DOE obtained price quotes directly from suppliers of the manufacturers for 

the units being analyzed. DOE assumed that the components in Table 5.3.2 were purchased from 

outside suppliers. 

5-5 
 

Table 5.3.2 Purchased WICF Components 

Assembly Purchased Sub-Assemblies 

Refrigeration Equipment Components 

Condensing Unit 

Compressor 

Condenser Fan Blade 

Condenser Fan Motor 

Condenser Coil 

Filter/Dryer 

Hi/Low Pressure Switch 

Accumulator 

Valves 

Plastic Parts 

Evaporating Unit 

Evaporator Fan Blade 

Evaporator Fan Motor 

Evaporator Coil 

Defrost Heater Rods 

Distribution Header 

TXV/EEV/Orifice 

Plastic Parts 

Controls 

Control Boards 

Capacitors, transformers, contactors, etc. 

Envelope Components 

Non-Display Door Assembly 

Hinges 

Kick Plate 

Door closing mechanism 

Latch Assembly 

Gasketing 

Door Sweep 

Camlocks 

Temperature Gauge 

Heater wire (for freezers only) 

Heater accessories (for freezers only) 

Display Door Assembly Pre-Assembled Unit (glazing, heater wire, light fixtures, 

hinges etc) 

Panel Assembly 

Camlocks 

Gaskets 

Insulation (for board stock only) 

Caulking for panel-to-floor interface 

As previously stated, variability in the costs of purchased parts can account for large 

changes in the overall MPC values calculated. Purchased part costs can vary significantly based 

on the quantities desired and the component suppliers chosen. The purchased part prices used in 

this study were typical values based on estimated production volume and other factors. However, 

variability in these prices would exist in reality on a case-by-case basis. 

5-6 
Due to the great diversity of manufacturing scale in the WICF industry, DOE estimates 

that the purchased parts costs in particular could vary significantly by manufacturer. Purchased 

parts make up roughly 60-70% of the MPC for refrigeration equipment and 20-30% of the 

envelope MPC. Additionally, some parts like heat exchanger coils, control systems, and foam 

insulation may be produced in-house by some manufacturers and purchased by others, changing 

likely overall system costs and investment requirements. For the preliminary analysis, DOE 

determined an average for the MPC based on an estimated market share of 50 percent for 

manufacturers who purchase the coils and 50 percent for manufacturers who make the coil inhouse. 

DOE also made several assumptions regarding the purchase costs of control systems, 

including defrost control, fan motor control, and floating head pressure control. In surveying 

manufacturers and suppliers, DOE determined that the cost of these components varies widely 

among manufacturers and suppliers. Often, several of these functions are packaged together into 

a single control system. Most manufacturers and suppliers apply a significant markup to these 

control systems – both single-function and multi-function – that can be many times that of the 

components used to make them; this markup accounts for the labor and, more importantly, the 

expertise of the maker of these parts. The costs used in the engineering model reflect the price 

DOE estimated that a manufacturer in the walk-in industry would pay to purchase the controls 

from a supplier; however, DOE recognizes that a walk-in manufacturer who makes these 

components in-house would not see the same cost, yet would be able to charge a premium on to 

the purchaser. 

5.3.2.3 Factory Parameters 

Certain factory parameters, such as fabrication rates, labor rates, and wages also affect 

the cost of each unit produced. DOE factory parameter assumptions were based on internal 

expertise and manufacturer feedback. Table 5.3.3 and Table 5.3.4 below list the factory 

parameter assumptions used in the cost model. 

5-7 
 

 

 

 

 

 

Table 5.3.3 Factory Parameter Assumptions, Refrigeration Equipment 

Parameter Estimate 

Name-plate Production Capacity (units/year) 30,000 

Actual Annual Production Volume (units/year) 12,000 

Work Days Per Year (days) 250 

Assembly Shifts Per Day (shifts) 2 

Fabrication Shifts Per Day (shifts) 2.5 

Fabrication Labor Wages ($/hr) 16 

Assembly Labor Wages ($/hr) 16 

Assembly Worker Hours Per Year 3,600 

Fabrication Worker Hours Per Year 4,500 

Length of Shift (hrs) 8 

Units Per Day 48 

Average Equipment Installation Cost (% of purchase price) 10% 

Fringe Benefits Ratio 50% 

Indirect to Direct Labor Ratio 33% 

Average Scrap Credit (relative to base material cost) 30% 

Non-recyclable trash cost ($/lb) 0.01 

Building Cost ($/ft2

) 100170 

Worker Downtime 10% 

Building Life (in years) 3025 

Burdened Assembly Labor Wage ($/hr) 24 

Burdened Fabrication Labor Wage ($/hr) 24 

Supervisor Span (workers/supervisor) 25 

Supervisor Wage Premium (over fabrication and assembly wage) 30% 

Table 5.3.4 Factory Parameter Assumptions, Envelope 

Parameter Estimate 

Name-plate Production Capacity (complete walk-ins/year) 30,000 

Actual Annual Production Volume (complete walk-ins/year) 12,000 

Work Days Per Year (days) 250 

Assembly Shifts Per Day (shifts) 2 

Fabrication Shifts Per Day (shifts) 2.5 

Fabrication Labor Wages ($/hr) 16 

Assembly Labor Wages ($/hr) 16 

Assembly Worker Hours Per Year 3,600 

Fabrication Worker Hours Per Year 4,500 

Length of Shift (hrs) 8 

Panels Per Day 48 

Average Equipment Installation Cost (% of purchase price) 10% 

Fringe Benefits Ratio 50% 

Indirect to Direct Labor Ratio 33% 

Average Scrap Credit (relative to base material cost) 30% 

Non-recyclable trash cost ($/lb) 0.01 

Building Cost ($/ft2

) 170 

Worker Downtime 10% 

Building Life (in years) 25 

Burdened Assembly Labor Wage ($/hr) 24 

Burdened Fabrication Labor Wage ($/hr) 24 

Supervisor Span (workers/supervisor) 25 

Supervisor Wage Premium (over fabrication and assembly wage) 30% 

5-8 
 

5.3.3 Downstream Analyses 

The MSPs derived in the engineering analysis are inputs to the life-cycle cost analysis 

(LCC) and the manufacturer impact analysis (MIA). In the LCC, the MSPs are necessary to 

calculate the total installed cost of each unit. In the MIA, DOE constructs a number of scenarios 

that analyze how different pricing schemes impact manufacturers financially. Hence, both the 

MSP and the direct production cost components of MSP are important drivers of results in the 

MIA. In chapters 8 and 12 of the preliminary TSD, respectively, DOE discusses how the 

engineering analysis results are used for those sections in greater detail. 

5.3.4 Manufacturer Selling Price Estimates 

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

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

determined a manufacturer markup, and applied this markup to the MPC to arrive at the MSP for 

each equipment class. Wholesaler, distributor, and other markups are determined in the markups 

analysis (see chapter 6 of the preliminary TSD). 

The manufacturer markup is a market-share-weighted average value for the industry. 

DOE developed this markup by examining several WICF manufacturers’ gross margin 

information from annual reports and Securities and Exchange Commission 10-K reports. The 

manufacturers analyzed by DOE account for the majority of the WICF market, and some of these 

companies are subsidiaries of more diversified parent companies that manufacture equipment 

other than walk-in coolers and freezers. 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. 

DOE evaluated markups for 2004 through 2008, calculating the manufacturer markup as 

100/(100 – average gross margin), where average gross margin is calculated as revenue – cost of 

goods sold. Taking this information into consideration, DOE is using an industry-wide 

manufacturer markup of 1.39 in the engineering analysis. 

The cost of specific models⎯or cost to an individual manufacturer to produce walk-in 

cooler or freezer equipment⎯will vary depending on the equipment’s precise design and 

features, actual manufacturing processes, the equipment mix in the factory, and other production 

factors. There are also considerable differences in the levels of vertical integration that affect 

cost structure and, hence the cost of equipment. Companies with a large market share and/or 

revenue base tend to be more vertically integrated than lower-volume competitors. 

In order to calculate the most likely selling price, DOE researched the industry to 

determine the markups that manufacturers charge on top of the MPC. DOE determined that the 

average markup for the industry is 1.39. The MSP is a product of the MPC and the manufacturer 

markup, added to the outbound freight cost from the manufacturer to the distributor (freight from 

the distributor to other points in the distribution chain, including the end-user, is covered in 

downstream analyses. The components of MSP are shown in greater detail in Figure 5.3.2.The 

outbound freight cost is captured in the non-production cost under “other costs.” 

5-9 
MSP 

Full Cost of Production 

Manufacturer Production Costs 

Direct 

Labor 

Direct 

Material Overhead Depreciation 

Non-Production Costs Profit 

EBIT 

Research & 

Development 

Costs 

Other 

Costs 

Selling, 

General, and 

Administrative 

Costs 

Figure 5.3.2 Components of Manufacturer Selling Price 

5.4 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 energy consumption of envelopes 

and refrigeration systems of walk-in coolers and freezers at various performance levels using a 

design-options approach. DOE developed the energy consumption model as a Microsoft Excel 

spreadsheet. 

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

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

calculates energy consumption at each performance level separately. For the baseline level, DOE 

calculated a corresponding MPC using the cost model (described in section 5.3 above). For each 

level above the baseline, DOE used the cost increases of the various design options to recalculate 

the MPC. 

5.4.1 Screened-In Technologies 

In the market and technology assessment (chapter 3 of the preliminary TSD), DOE 

defined an initial list of technologies that can be used to reduce the energy consumption of walkin coolers and freezers. DOE then analyzed the following technology options: 

5.4.1.1 Screened in Technologies for Envelopes 

• Improved wall, ceiling, and floor insulation 

• Improved door gaskets and panel interface systems 

• Electronic lighting ballasts and high-efficiency lighting 

• Occupancy sensors 

• Automatic door opening and closing systems 

• Air curtains 

• Strip curtains 

• Vestibule entryways 

5-10 
• Display and window glass system insulation performance 

• Anti-sweat heater controls 

• No anti-sweat systems 

5.4.1.2 Screened in Technologies for Refrigeration Systems 

• Ambient subcooling 

• High-efficiency compressors (including scroll, 2-speed, and variable speed) 

• Condenser coil 

• Condenser fan motors 

• Condenser fan blades 

• Evaporator coil 

• Evaporator fan blades 

• Evaporator fan control 

• Floating head pressure 

• Defrost controls 

5.4.2 Screened-In Technologies Not Considered in the Engineering Analysis 

In the screening analysis (chapter 4 of the preliminary TSD), DOE narrowed this list by 

eliminating those technologies that can reduce annual energy consumption of walk-in coolers 

and freezers but do not reduce energy consumption as measured under the DOE test procedure. 

DOE then screened out those technologies that were not feasible, were not practical to 

manufacture, reduced equipment utility, or were considered unsafe. 

The remaining list of screened-in technologies became an input to the engineering 

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

the energy consumption model. These include the following: 

5.4.2.1 Ambient Subcooling 

This process utilizes an oversized condenser or subcooling heat exchanger in order to 

further cool the condensed refrigerant. The result is a decrease in coolant enthalpy and an 

increase in specific capacity, meaning that a lower mass flow rate of compressed refrigerant, and 

thus less compressor power, is needed. Ambient subcooling is only needed when head pressure 

has been reduced to the lowest allowable value; in any other case, it is more efficient to simply 

reduce the head pressure. This system then proves effective when the ambient temperature is low 

enough that the head pressure must be kept at a high level, as is often the case for systems 

operating in cooler geographical regions. 

DOE intends to include floating head pressure as a design option, as well as increasing 

the size of the condenser. This will have a similar effect to ambient subcooling, and as reducing 

the head pressure is more efficient, it was not necessary to implement ambient subcooling as a 

design option. 

5-11 
5.4.2.2 High Efficiency Two-speed and Variable-speed Compressors 

Two- or multiple-capacity compressors present an opportunity for energy savings. These 

systems can take many forms, including single compressors with multiple stages or variable 

operating speeds as well as coupled sets of compressors which engage as necessitated by the load 

on the envelope. These technologies allow for the compressor operating time and power to more 

closely follow the heat load, resulting in improved performance and decreased energy 

consumption. This would save energy as measured by the test procedure, in reducing cyclic 

losses of the system. However, DOE’s energy consumption model calculates the energy 

consumption analytically based on published data, and does not capture these cyclic losses. Also, 

DOE was unable to find published energy use data for two-speed and variable-speed 

compressors, so was unable to analytically determine the energy savings. Thus, DOE did not 

consider this option in the engineering analysis, but will consider this option in a future stage of 

the rulemaking if data are available. 

5.4.3 Design Options 

After conducting the screening analysis and removing from consideration those technologies 

described above, the following technologies were implemented as design options in the energy 

consumption model: 

Envelope: 

• Improved Wall, ceiling, and floor insulation 

• Improved Door gaskets and panel interface systems 

• Electronic lighting ballasts and high-efficiency lighting 

• Occupancy sensors and automatic door opening and closing systems 

• Air curtains and strip curtains 

• Vestibule entryways 

• Display and window glass system insulation enhancement 

• Anti-sweat heater controls and no anti-sweat systems 

Refrigeration: 

• High-efficiency compressors 

• Improved condenser coil 

• High-efficiency condenser fan motors 

• Improved condenser fan blades 

• Improved evaporator coil 

• Improved evaporator fan blades 

• Evaporator fan controls 

• Floating head pressure 

• Defrost controls 

Table 5.4.1 through Table 5.4.3 show the baseline options for each equipment class for envelope 

and refrigeration, respectively. Sections 5.4.4.1 through 5.4.5.8 contain details for the improved 

technologies. 

5-12 
Table 5.4.1 Baseline Design Options for Envelope, Non-Display 

Design Options ND.C. Small ND.C. Medium ND.C. Large ND.F. Small ND.F. Medium N

Wall and Ceiling Insulation Thickness Baseline Thickness, 4" Baseline Thickness, 4" Baseline Thickness, 4" Baseline Thickness, 4" Baseline Thickness, 4" 

T

Floor Insulation Option Baseline Floor Baseline Floor Baseline Floor Baseline Floor Baseline Floor 

Insulation Materials A 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

X

Insulation Materials B None None None None None 

Display Door Enhancement - - - - - 

Sealant Enhancement Baseline Gasket Baseline Gasket Baseline Gasket Baseline Gasket Baseline Gasket 

Active Infiltration Reduction Devices None None None None None 

Passive Infiltration Reduction Devices No Device No Device No Device No Device No Device 

Door Systems 

Baseline door 

closing 

mechanisms 

Baseline door 

closing 

mechanisms 

Baseline door 

closing 

mechanisms 

Baseline door 

closing 

mechanisms 

Baseline door 

closing 

mechanisms 

B

Anti-Sweat Heaters - - - - - 

Lighting: Display - - - - - 

Lighting: Non-Display 

Compact 

Florescent 

Bulb 

Compact 

Florescent 

Bulb 

Compact 

Florescent 

Bulb 

Compact 

Florescent 

Bulb 

Compact 

Florescent 

Bulb 

Additional Control System No Control No Control No Control No Control No Control 

5-13 
Table 5.4.2 Baseline Design Options for Envelope, Display 

Design Options D.C. Small D.C. Medium D.C. Large D.F. Small D.F. Mediu

Wall and Ceiling Insulation Thickness Baseline Thickness, 4" Baseline Thickness, 4" Baseline Thickness, 4" Baseline Thickness, 4" Baseline Thickness, 4

Floor Insulation Option Baseline Floor Baseline Floor Baseline Floor Baseline Floor Baseline Flo

Insulation Materials A 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

Baseline 

Insulation 

Material, 

XPS/PU Avg. 

Baseline 

Insulation 

Material, 

XPS/PU Av

Insulation Materials B None None None None None 

Display Door Enhancement Baseline Glass Baseline Glass Baseline Glass Baseline Glass Baseline Gla

Sealant Enhancement Baseline Gasket Baseline Gasket Baseline Gasket Baseline Gasket Baseline Gasket 

Active Infiltration Reduction Devices None None None None None 

Passive Infiltration Reduction Devices No Device No Device No Device No Device No Device 

Door Systems - - - - - 

Anti-Sweat Heaters No Controller No Controller 

Anti-Sweat 

Heater 

Controls 

No Controller No Controll

Lighting: Display 

5 foot, T8 

Electronic, 

Normal 

Lumen Blub, 

Normal BF 

Electronic 

Ballast 

5 foot, T8 

Electronic, 

Normal 

Lumen Blub, 

Normal BF 

Electronic 

Ballast 

5 foot, T8 

Electronic, 

Normal 

Lumen Blub, 

Normal BF 

Electronic 

Ballast 

5 foot, T8 

Electronic, 

Normal 

Lumen Blub, 

Normal BF 

Electronic 

Ballast 

5 foot, T8 

Electronic

Normal 

Lumen Blub

Normal BF 

Electronic 

Ballast 

Lighting: Non-Display - - - - - 

Additional Control System No Control No Control No Control No Control No Contro

5-14 
Table 5.4.3 Baseline Design Options for Refrigeration Systems 

Design Option DC.M.I DC.M.O MC.M DC.L.I DC.L.O Evaporator Coil Standard Coil Standard Coil Standard Coil Standard Coil Standard Coil 

Evaporator Fan Motor Controllers No Controls No Controls No Controls No Controls No Controls 

Evaporator Fan Blades Standard Blades Standard Blades Standard Blades Standard Blades Standard Blades 

Condenser Coil for DC Standard Coil Standard Coil - Standard Coil Standard Coil 

Condenser Fan Motors for DC 

Permanent Split 

Capacitor Motor 

Permanent Split 

Capacitor Motor 

-

Permanent Split 

Capacitor Motor 

Permanent Split 

Capacitor Motor 

Condenser Fan Blades for DC Standard Blades Standard Blades - Standard Blades Standard Blades 

Compressor Type for DC 

Hermetic 

Compressor 

Hermetic 

Compressor 

-

Hermetic 

Compressor 

Hermetic 

Compressor 

Defrost Controls for XX.L 

- - - Timed Defrost Timed Defrost 

Floating Head Pressure DC.X.O 

-

Fixed Head 

Pressure 

- -

Fixed Head 

Pressure 

5-15 
 

 

5.4.4 Details for Envelope Design Options 

Table 5.4.4 summarizes the design option codes and descriptions for each envelope 

design option. Sections 5.4.4.1 through 5.4.4.8 contain details for improved technologies for 

envelopes. 

5-16 
 

 

 

 

 

 

 

 

 

 

 

Table 5.4.4 Design Option Codes and Descriptions for Envelopes 

Design Option Code Description 

Wall and Ceiling Insulation Thickness 

TCK1 Baseline Thickness 

TCK2 10% Thicker Insulation 

TCK3 25% Thicker Insulation 

TCK4 50% Thicker Insulation 

TCK5 75% Thicker Insulation 

Floor Insulation Option 

FLR1 Baseline Floor 

FLR2 Cooler and Enhanced Freezer Floor 

FLR3 Enhanced Floor 

Insulation Materials A 

INS1 Baseline Insulation Material, XPS and PU 

Insulation Materials B 

NONE None 

INSH1 Hybrid 1-VIP + INS1 

VIP Vacuum insulated Panel 

Display Door Enhancement 

DR1 Baseline Glass 

DR2 Enhanced 1 

DR3 Enhanced 2 

DR4 Superenhanced 

Sealant Enhancement 

SE1 Baseline Gasket 

XC Extra Caulking 

ATG Advanced Tongue and Groove and Door Sweep 

Active Infiltration Reduction Devices 

NOARD None 

AC Air Curtain 

Passive Infiltration Reduction Devices 

NOIRD Baseline No Device 

SC Strip Curtain 

Door Systems 

DRSTD Baseline door closing mechanisms 

VEST Vestibule 

Anti-Sweat Heaters 

ASHNC Baseline (No Controller) 

ASCTRL Anti-Sweat Heater Controls 

Lighting: Display 

T8 

5 foot, T8 Electronic, Normal Lumen Blub, 

Normal BF Electronic Ballast 

LED 5 foot, LED 

Lighting: Non-Display 

CFL Compact Florescent Bulb 

LED LED Bulb 

Control System 

CS1 Baseline No Control 

5-17 
 

CS2 Lighting Sensors 

CS3 Lighting sensors and Door Opening Control 

5.4.4.1 Improved Wall, Ceiling, and Floor Insulation 

Wall and Ceiling Insulation Thickness 

The thermal resistance of insulating materials increases approximately linearly with 

material thickness. Based on DOE’s analysis and public comment, a typical WICF utilizes four 

inches of foam insulation in the walls and ceiling to slow the rate of heat conduction from the 

external environment to the internal cooled space of the walk-in. In addition, DOE found that 

many WICF manufacturers offer insulation in thicknesses of four, five and six inches. 

Therefore, in the engineering analysis, DOE considered insulation thickness as one of the 

two independent variables that impacts full wall R-value. DOE assessed the incremental increase 

in cost due to additional material cost and separately evaluated the impact on shipping cost. 

Details of the analysis for material/labor and shipping cost are found in Table 5.4.5 through 

Table 5.4.8 below. 

Table 5.4.5 Details for “Wall and Ceiling Insulation Thickness” Design Option 

Code Description Thickness 

[inch] 

Extra Material/Labor 

Cost [$/ft2

] 

TCK1 Baseline Thickness 4.0 $ ­

TCK2 10% Thicker Insulation 4.4 $ 0.220 

TCK3 25% Thicker Insulation 5.0 $ 0.550 

TCK4 50% Thicker Insulation 6.0 $ 1.130 

TCK5 75% Thicker Insulation 7.0 $ 1.710 

Table 5.4.6 Details for “Wall and Ceiling Insulation Thickness” Design Option Cont. 

Thickness [in] Calc. Type Units Calculation Slope Intercept 

4 

Weight lbs 

Calculated 1.884 311.040 

5 Calculated 2.014 334.960 

6 Calculated 2.198 322.190 

4 

Shipping 

Cost- Base $ 

Calculated 0.353 -102.670 

5 Calculated 0.353 -102.670 

6 Calculated 0.353 -102.670 

4 

Shipping 

Cost- Fuel $ 

Calculated 0.102 -76.074 

5 Calculated 0.102 -76.074 

6 Calculated 0.102 -76.074 

5-18 
 

 

Table 5.4.7 Details for “Wall and Ceiling Insulation Thickness” Design Option Cont. 

Total 

External 

Area 

Thickness 

Input From 

Model From Model Slope Intercept 

Output 

Weight Interpolated lbs Calculated Calculated 

Base Interpolated $ Calculated Calculated 

Fuel Interpolated $ Calculated Calculated 

Total Interpolated $ Calculated Calculated 

Table 5.4.8 Total Shipping Cost for Product Classes and Thicknesses Considered 

Design Option TCK1 TCK2 TCK3 TCK4 TCK5 

Wall Thickness 

[Inch] 4 4.4 5 6 7 

ND.C. Small $ 266.19 $ 277.26 $ 293.87 $ 321.56 $ 349.24 

ND.C. Medium $ 688.01 $ 713.19 $ 750.96 $ 813.91 $ 876.87 

ND.C. Large $1,729.36 $1,789.36 $1,879.38 $2,029.40 $2,179.42 

D.C. Small $ 130.69 $ 137.23 $ 147.05 $ 163.40 $ 179.76 

D.C. Medium $ 249.01 $ 259.51 $ 275.25 $ 301.50 $ 327.75 

D.C. Large $2,218.50 $2,294.87 $2,409.42 $2,600.34 $2,791.25 

ND.F. Small $ 228.52 $ 238.33 $ 253.06 $ 277.59 $ 302.13 

ND.F. Medium $ 741.70 $ 768.67 $ 809.14 $ 876.58 $ 944.02 

ND.F. Large $1,737.88 $1,798.17 $1,888.61 $2,039.34 $2,190.08 

D.F. Small $ 161.37 $ 168.94 $ 180.29 $ 199.21 $ 218.13 

D.F. Medium $ 309.85 $ 322.39 $ 341.19 $ 372.52 $ 403.86 

D.F. Large $3,241.10 $3,351.67 $3,517.52 $3,793.94 $4,070.35 

DOE’s analysis found that the incremental cost of manufacturing thicker products was 

dominated by material cost. The results of the analysis, for the various thicknesses, are shown in 

“Extra Material/Labor Cost” column of Table 5.4.5. The impact on shipping is a more complex 

calculation based on the final weight of a WICF product. The shipping weight is independently 

impacted by both the total surface area (or size) of a walk-in and selected insulation thickness. 

Then, the cost of shipping is dependent on a base charge (based on density and shipping class) 

and a fuel surcharge based on the distance shipped and weight. 

Due to the multivariate nature of this calculation, best fit linear equations were first 

developed to calculate the weight of a given product based on its surface area and thickness (the 

slope and intercepts are shown in Table 5.4.6 above). Then using the calculated weight for a 

given thickness and area, the base and fuel cost of shipping could be developed. Finally, linear 

best fits of the shipping cost calculations were made as shown in Table 5.4.7. These last 

equations then allowed the model to interpolate the shipping cost based on any thickness ranging 

from two to seven inches in thickness. Table 5.4.8 shows the baseline calculations of shipping 

weight and cost for all product classes. 

5-19 
 

 

 

 

 

 Floor Insulation 

Since floor insulation is generally selected independently in standard WICF design 

practice, the floor insulation was treated as such in the engineering analysis. In addition, EPCA 

specified that insulated floors with a minimum of R-28 are required for walk-in freezers (not for 

coolers), requiring that freezers and coolers be treated differently. Therefore, DOE selected an 

uninsulated floor and four inches of insulation (approximately equivalent to R-28) for the 

baseline options for walk-in coolers and freezers respectively. Due to the inherently complex 

heat transfer physics of floor heat transfer, DOE developed finite element analysis (FEA) models 

to numerically solve for the average heat flux through the floor of WICF. The models used 

assumed design operating temperatures of -10 °F for freezers and 35 °F for coolers. The FEA 

results, for various floor sizes, are shown below in Table 5.4.9. FLR1 is the baseline option for 

both coolers and freezers while FLR2 and FLR3 reflect results of increasing thickness of 

insulation. 

Table 5.4.9 Details for “Floor Insulation” Design Option, FEA Results 

FEA Results Average Heat Flux [Btu/h-ft2

] 

Floor Area 

[ft2

] FLR1 FLR2 FLR3 

Cooler 

36 8.61 1.48 1.21 

71.4 7.31 1.43 1.18 

80 6.9 1.41 1.17 

240 4.4 1.31 1.1 

750 2.97 1.13 0.97 

1200 3.04 1.18 1.01 

Freezer 

36 3.15 2.59 2.2 

48 3.11 2.56 2.18 

71.4 3.04 2.51 2.14 

180 2.88 2.4 2.06 

500 2.54 2.16 1.88 

1200 2.51 2.14 1.86 

Table 5.4.10 shows the design option inputs used to complete the FEA simulations: 

Table 5.4.10 Details for “Floor Insulation” Design Option, FEA Inputs 

Code Description Thickness 

Cooler 

Thickness 

Freezer 

R-value 

Cooler 

R-value 

Freezer 

FLR1 Baseline Floor 0 4 0.0 22.42 

FLR2 Cooler and Enhanced 

Freezer Floor 4.00 5.00 22.42 28.03 

FLR3 Enhanced Floor 5.00 6.00 28.03 33.64 

Floor construction, when a WICF manufacturer provides the floor, is similar to the 

typical WICF wall panel construction. Therefore, the same cost model for WICF wall panels was 

5-20 
 

 

used to calculate the incremental cost increase for each design option. The results used in the 

engineering analysis are shown in Table 5.4.11. 

Table 5.4.11 Details for “Floor Insulation” Design Option, Cost 

Code 

Normalized 

Insulation Cost 

[$/ft2] 

Cooler 

Normalized 

Insulation Cost 

[$/ft2] 

Freezer 

FLR1 $0.00 $6.66 

FLR2 $6.66 $7.23 

FLR3 $7.23 $7.88

 Insulation Materials A 

Based on DOE analysis and stakeholder comments, DOE concluded that WICF 

manufacturers almost exclusively currently use one of two foam insulation types: board stock 

extruded polystyrene (XPS) or foam-in-place polyurethane (PU)iii. The thermal resistance 

performance characteristics of each product type are quite similar, as well as the total cost 

associated with a given material. Therefore, DOE averaged the material properties for the 

baseline design option as shown in Table 5.4.12. This represents the second of the two 

independent variables that impact full wall R-value (insulation thickness, the first, was described 

earlier). Since foam materials were considered the baseline option, foam materials are considered 

to have zero cost when compared to additional material options. 

Table 5.4.12 Details for “Insulation Materials A” Design Option 

Code Description 

R-value/inch 

composite 

INS1 Baseline Insulation Material, XPS and PU 5.902

 Insulation Materials B 

DOE found that several other insulating materials or systems are commercially available 

but have limited market penetration. These include, but are not limited to, vacuum insulated 

panels (VIPs), aerogel materials, and hybrids of these and traditional foam materials. In order to 

account for these high R-value (and generally high cost) alternatives, DOE incorporated these 

options into the engineering analysis. The cost and performance data are based on discussions 

with manufacturers and DOE internal analysis. DOE estimated that the cost of R-10/inch aerogel 

was $8.00-$13.00 or approximately $1.00/[ ft2

-F-h/Btu/inch]. DOE found that thin VIPs encased 

in standard foam (represented by INSH1) and VIPs alone have $/[ft2-F-h/Btu/inch]ratios of 

approximately $0.10 and $0.13 respectively. For comparison, DOE estimates that standard foam 

such as XPS or PU has a cost-performance ratio of $0.02 /$/[ft2

-F-h/Btu/inch]. DOE concluded 

that at current market price and performance per inch, aerogel products are not a viable 

alternative to VIPs for use in walk-in coolers and freezers and therefore were not included in the 

engineering analysis. 

5-21 
 

 

 

 

 

Table 5.4.13 Details for “Insulation Materials B” Design Option 

Code Description 

Wall 

Thickness % 

Wall 

Thickness % 

Full 

Thickness 

[inch] 

NONE None 

INSH1 Hybrid 1-VIP + 

INS1 75% 25% 2 

VIP Vacuum 

Insulated Panel 100% 0% 2 

Table 5.4.14 Details for “Insulation Materials B” Design Option, Continued 

Code 

Other 

Insulation 

Cost [$/brdft] 

Foam 

Insulation 

Cost 

[$/brd-ft] 

Insulation 

Cost [$/ft2

] 

@ 2" 

Thickness 

composite 

Other Rvalue/ 

inch 

Foam 

R-value 

/inch 

R-value 

/inch 

composite 

R-value 

composite 

@ Full 

Thickness 

NONE - - - - - - -

INSH1 $3.88 $0.40 $6.02 37.00 5.90 29.15 58.30 

VIP $4.70 $0.00 $9.40 37.00 37.00 37.00 74.00 

In order for a manufacturer to incorporate these advanced insulating materials, significant 

engineering and tooling costs would be incurred. These costs are amortized over the life of the 

equipment and divided by the assumed annual unit production. The result is levelized cost per 

square foot of WICF panel produced. These assumptions and calculations are shown in Table 

5.4.15 and Table 5.4.16 below. 

Table 5.4.15 Details for “Insulation Materials B” Design Option, Engineering Cost 

Engineering Costs 

Design Option INSH1 VIP 

Description Hybrid 1-VIP + 

INS1 

Vacuum Insulated 

Panel 

Assumed costs to 

design system, 

manufacturing 

process, and tooling 

$ 200,000.00 $ 500,000.00 

New Equipment Cost $ 150,000.00 $ 300,000.00 

Design Lifetime 

[Years] 7 7 

Units per Year 

[unit = ft2] 11,200,000 11,200,000 

Cost Per Unit [ft2]* $ 0.004 $ 0.010 

*Assuming 4’ X 8’ panel 

5-22 
 

 

 

Table 5.4.16 Details for “Insulation Materials B” Labor Cost 

Labor Costs 

Item Hybrid 1-VIP + 

INS1 

Vacuum Insulated 

Panel 

Additional Labor 

[minutes/per panel] 10 15 

Labor Rate [$/Hr] $ 24.00 $ 24.00 

Cost Per Unit [ft2] $ 0.13 $ 0.19 

5.4.4.2 Improved Door Gaskets and Panel Interface Systems

 Sealant Enhancement 

The main pathway for air exchange during steady-state operation of WICF is through the 

panel-to-panel interfaces and door gaskets. In particular, non-display type doors that utilize door 

sweeps are prone to slight air leakage. Typical WICF construction consists of a cam-lock system 

that squeezes neighboring panels together. This provides a compression force on gaskets that are 

normally placed between the panels, creating a reasonably well sealed interface. DOE considered 

this type of construction the baseline option in the engineering analysis. However, additional 

designs exist that utilize tongue-and-groove construction (see Figure 5.4.1 below) and novel 

locking systems that further reduce air exchange. In addition, simply adding additional sealant to 

the panel-to-panel and panel-to-floor interface may reduce air infiltration. Both the advanced 

and simple improvements are reflected in Advanced Tongue and Groove (ATG) and Extra 

Caulking (XC) and design options in the engineering analysis. 

Figure 5.4.1 Panel Tongue and Groove Construction 

DOE research found that advanced tongue and groove design is capable of reducing 

infiltration rates to at least 0.06 ft3/h-ft2 (flow rate per unit of external surface area). The resulting 

calculations for each product class and analysis point are shown in Table 5.4.17 and Table 5.4.18 

below. Advanced tongue-and-groove design was considered the max-tech option, and the 

corresponding infiltration rate was used to reverse calculate the performance of the previous 

design options in the engineering analysis. DOE estimated that about one third of the total 

steady-state infiltration was caused by losses through the door sweep of non-display WICF 

passage doors. 

5-23 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 5.4.17 Details for “Sealant Enhancement” Design Option 

Code Description 

Material 

[$/ft2] or 

[$/lin-ft] 

SE1 Baseline 

Gasket $ ­

XC Extra 

Caulking $ 0.09 

ATG 

Advanced 

Tongue and 

Groove and 

Door Sweep 

$ 1.23 

Table 5.4.18 Details for “Sealant Enhancement” Design Option, Cont. 

Total 

External 

Surface 

Area 

Display 

Doors 

Passage 

Doors 

Freight 

Doors SE1 XC ATG 

Units ft2

 - ft3

/h 

ND.C. 

Small 433 0 1 0 56 50 28 

ND.C. 

Medium 1088 0 1 1 141 125 70 

ND.C. 

Large 2820 0 2 1 487 447 218 

D.C. 

Small 230 3 1 0 30 26 15 

D.C. 

Medium 404 8 1 0 52 47 26 

D.C. 

Large 3844 50 2 0 664 609 297 

ND.F. 

Small 309 0 1 0 40 36 20 

ND.F. 

Medium 911 0 1 1 118 105 59 

ND.F. 

Large 2080 0 2 1 359 329 161 

D.F. 

Small 230 3 1 0 30 26 15 

D.F. 

Medium 404 8 1 0 52 47 26 

D.F. 

Large 3844 50 2 0 664 609 297 

The assumptions used to calculate the incremental cost associated with each design 

option are shown in Table 5.4.19 through Table 5.4.21 below. 

5-24 
 

 

 

 

 

 

 

 

Table 5.4.19 Details for “Sealant Enhancement” Design Option, Engineering Cost 

Engineering Costs Advanced Tongue 

and Groove 

Advanced Door 

Sweep 

Item Value Value 

Assumed costs to design system, manufacturing 

process, and tooling $ 100,000.00 $ 80,000.00 

New Equipment Cost $ 50,000.00 $ 25,000.00 

Design Lifetime [Years] 7 7 

Units per Year [unit = ft2

] 11200000 14400 

Cost Per Unit $ 0.002 $ 1.042 

Table 5.4.20 Details for “Sealant Enhancement” Design Option, Labor Cost 

Labor Costs Advanced Tongue 

and Groove 

Advanced Door 

Sweep 

Item Value Value 

Additional Labor [minutes] 5 10 

Labor Rate [$/h] $ 24.00 $ 24.00 

Cost Per Unit $ 0.06 $ 0.13 

Table 5.4.21 Details for “Sealant Enhancement” Design Option, Material Cost 

Caulking Assumptions 

Item Value 

Tube Size [Fluid Oz] 10 

Tube Cost [$] $ 4.00 

Cross-sectional Area of Bead [inch2

] 0.0351 

Volume of Caulk [Fl Oz/Lin-ft] 0.233 

Linear Feet per Tube 42.85 

Cost per Linear Foot $ 0.09 

5.4.4.3 Electronic Lighting Ballasts and High-Efficiency Lighting 

Since the associated lighting systems for display and non-display type WICF are quite 

different, DOE split the lighting engineering analysis by the display and non-display 

characteristic. This helped simplify the model calculations and provides more clarity on design 

options used. 

 Lighting: Display 

EPCA specified minimum efficacy of 40 lumens/W, including ballast losses, for all 

lights. (42 U.S.C. 6313(f)(1)(G) Therefore, DOE did not consider any lighting systems that did 

not meet this limit. In addition, DOE analysis indicated that the lighting industry had mostly 

shifted to high efficiency, electronic ballasted lighting systems. DOE also noted that a number of 

display door manufacturers have eliminated the use of florescent systems and now use LED 

lighting systems as their baseline option. DOE is considering the use of LEDs as the baseline 

option but completed the preliminary engineering analysis using T8 bulbs with electronic ballasts 

5-25 
 

 

 

as the baseline option. The associated performance and cost data used in the model are shown in 

Table 5.4.22 through Table 5.4.25 below. 

Table 5.4.22 Details for “Lighting: Display” Design Option, Performance Data 

Code Description Lamp Power 

[W/bulb] 

Ballast Power 

[W/bulb] 

T8 

5 foot, T8 Electronic, Normal 

Lumen Blub, Normal BF 

Electronic Ballast 

54.5 3.5 

LED 5 foot, LED 16.1 0.0 

Table 5.4.23 Details for “Lighting: Display” Design Option, Performance Data Cont. 

Lamp Ballast System 

Code 

Type 

Rated 

Power 

[W] 

Rated 

Lumens 

Number 

of 

Lamps 

Ballast 

Factor 

Total Input 

Power [W] 

Efficacy 

[LPW] 

Light 

Output 

[Lumens] 

T8 F32T8/HL 58.0 3100 1 0.94 58.0 50.2 2914.0 

LED - 16.1 1342 1 1.00 16.1 53.9 1342.0 

Table 5.4.24 Details for “Lighting: Display” Design Option, Cost Data 

Cost 

Code Description Lamp Ballast Total 

T8 

5 foot, T8 Electronic, Normal 

Lumen Blub, Normal BF 

Electronic Ballast 

$10.99 $14.00 $24.99 

LED 5 foot, LED $115.00 - $115.00 

Table 5.4.25 Details for “Lighting: Display” Design Option, Cost Data Cont 

Description Avg. OEM Price 

120-277V Electronic Ballast T8 lamps (-20F starting capability) $14.00 

Description Average 

Wholesale Price 

5' 58W T8 low-temp lamp $10.99 

LED System Cost Estimate Value 

LED power use, 1-row 5' fixture [W] 16.1 

Average OEM Cost of 1-row 5' LED fixture $115.00 

Lighting: Non-Display 

As for display type walk-ins, DOE only considered design options with at least 40 

lumens/W efficacy for non-display WICF. The two readily available technologies that meet this 

standard are light emitting diode (LED) bulbs and compact florescent light (CFL) bulbs. LED 

bulbs are higher performing and significantly more expensive than CFLs, therefore DOE 

selected CFLs as the baseline design option for non-display systems. The data used for 

calculations in the engineering analysis are shown in Table 5.4.26. 

5-26 
 

 

Table 5.4.26 Details for “Lighting: Non-Display” Design Option 

Code Description 

Bulb 

Power 

[W/bulb] 

Ballast 

Power 

Bulb 

Cost 

[$] 

Rated 

Power 

[W] 

Rated 

Lumens 

Efficacy 

[L/W] 

CFL 

Compact 

Florescent 

Bulb 

13.0 2.0 $1.50 15.0 825.0 55.0 

LED LED Bulb 7.0 - $35.00 7.0 450 64.3 

5.4.4.4 Occupancy Sensors and Automatic Door Opening and Closing Systems 

Control Systems 

DOE reviewed a number of control system related design options. While most control 

systems are designed to intelligently control the refrigeration equipment, there are a number of 

available features that are relevant to the envelope only. DOE found that most WICF 

manufacturers offer control systems but that there was limited end-user demand or market 

penetration. The exception was for anti-sweat heater controllers, which will be discussed in 

another section. Therefore, DOE considered the baseline design option to be a WICF without any 

type of control features, CS1. 

The next design option (CS2) DOE considered is occupancy sensors to control lights. 

This allows for “on demand” use of lights and helps prevent accidental wasted energy. As 

described in the proposed WICF test procedure, DOE recognizes that actual energy use will vary 

based on specific walk-in use or type. 75 FR 199. Therefore, the engineering analysis adopts the 

same assumption for percent time off (PTO) of devices that are regulated by control systems. 

The assumptions used in the analysis can be found in Table 5.4.27. The last option, CS3, 

incorporates the use of an automatic door opening and closing sensor. Using the same 

methodology in the WICF test procedure, the use of the automatic door devices is assumed to 

reduce the average time that a door remains open during each opening event. This reduces direct 

air infiltration through the door and corresponding energy use by the refrigeration equipment. 

Table 5.4.27 Details for “Control Systems” Design Option 

Code Description PTO 

Lights 

Automatic 

Door 

Open/Close 

PTO 

Other Cost 

CS1 Baseline No Control 25% NO 0% $ ­

CS2 Lighting Sensors 50% NO 0% $ 250.00 

CS3 Lighting sensors and Door 

Opening Control 50% YES 25% $ 450.00 

The cost estimates used for the various control system options were developed based on 

component and WICF manufacturer comments. 

5.4.4.5 Air Curtains and Strip Curtains 

Active Infiltration Reduction Devices 

5-27 
 

 

Active infiltration reduction devices (AIRDs), such as an air curtain, are devices that 

reduce air infiltration through open doorways that consume energy in order to function. While 

both passive and active devices serve the same purpose, DOE considered it important to classify 

them differently. AIRDs’ cost benefit ratio (and associated payback period) is dependent on the 

ratio of energy saved versus the energy used to operate the device rather than simply the energy 

saved for passive devices. In addition, active devices needed to be considered independently of 

passive devices as it is possible for these devices to be installed simultaneously in an actual 

walk-in. For example, strip curtains can serve as the primary method to reduce air exchange 

while an air curtain can act as a secondary reduction method. 

DOE considered air curtains as the only viable AIRD for walk-ins. The performance of 

these devices is normally measured in terms of effectiveness. An effectiveness of 1.0 

corresponds to a device that prevents 100% of air exchange from occurring when a door is open. 

Conversely, an effectiveness of zero means that the device does not reduce air exchange by a 

measureable amount. DOE assumed that the effectiveness of an air curtain, based on extensively 

cited ASHRAE researchiv, is 0.8. 

There is limited market penetration of air curtains, particularly for smaller sized WICF. 

Therefore, DOE selected a system without an air curtain for the baseline option. 

Table 5.4.28 Details for “Active Infiltration Reduction Devices” Design Option 

Code Description Effectiveness $/door Rated Power [W] 

NOARD None 0.00 $ ­

AC Air Curtain 0.80 $ 460.00 500.00 

Passive Infiltration Reduction Devices 

Strip curtains are the most widely used passive infiltration reduction devices (PIRDs) in 

WICF today. In addition, EPCA cites strip curtains as one “method of minimizing infiltration 

when doors are open.” However, DOE research found that throughout the industry there is 

limited preference to use vertically hung strip curtains in walk-ins. End-users complain that the 

vinyl strips are a nuisance because the strips brush against personnel’s faces and heads as they 

pass through the door. Therefore, WICF manufacturers typically select other methods to 

maintain EPCA compliance, such as spring hinged doors. 

Another option DOE considered was impact doors. These have been shown to have 

nearly identical effectiveness as strip curtains and are equally if not more transparent than strip 

curtains. Impact doors are generally constructed of two large overlapping transparent plastic 

flaps that are connected to the door frame using bi-directional hinges. After pushing through the 

flaps, the spring hinges swing the two flaps back into place to reduce air exchange. Since the 

flaps open to the sides, rather than being vertically hung like strip curtains, the material does not 

drag over the face or arms of personnel passing through the doorway. DOE has found that this is 

an important feature when considering end-user adoption. 

5-28 
 

 

 

 

 

 

However, impact doors are nearly twice as costly as strip curtains. While impact doors 

appear to be a practical alternative, the design options must be ordered such that the first option 

has the shortest payback period and the last has the longest payback. If the options do not follow 

this order then the engineering analysis produces nonsensical results. Compared to strip curtains, 

impact doors always have a higher cost but identical performance and therefore always have a 

longer payback period. Both because of the longer payback period and that the options have the 

same effectiveness, impact doors would never be selected in the model. For these reasons, DOE 

only considered strip curtains as a design option for PIRD. 

The assumed strip curtain effectiveness and cost estimates are shown in Table 5.4.29 

below. Strip curtains used for freezers must rely on materials that do not become brittle and/or 

fracture at low temperatures. Therefore, freezer strip curtains are typically more expensive than 

cooler strip curtains as shown in Table 5.4.29. 

Table 5.4.29 Details for “Passive Infiltration Reduction Devices” Design Option 

Cooler Freezer 

Code Description Effectiveness Cost 

[$/ft2] 

Cost 

[$/ft2] 

NOIRD Baseline No Device 0.00 $ ­ $ ­

SC Strip Curtain 0.90v $ 4.33 $ 5.28 

5.4.4.6 Vestibule Entryways

 Door Systems 

In addition to passive and active IRDs, DOE considered unique walk-in designs that 

could reduce the amount of air infiltration during door opening events. As described in Chapter 4 

revolving door systems were not considered in the engineering analysis due to impact on utility 

of the WICF. However, unlike revolving doors, vestibule entry ways are occasionally used for 

walk-ins. These entry ways are very effective at reducing direct air exchange. When the primary 

door is accessed the secondary door remains closed (see 

Figure 5.4.2). When the secondary door opens, the primary has already closed, substantially 

reducing air movement. In the engineering analysis, DOE created a design option that 

incorporates this design as shown in Table 5.4.30 below. For the cost and effectiveness, DOE 

only considered designs that utilized a standard WICF insulated hinged door as the primary and 

the secondary doors. Variations such as the primary or secondary entry way only protected by an 

air or strip curtain were not considered. The cost also includes the expense of additional wall 

panels that would be required to enclose the intermediate space between the primary and 

secondary entry-ways. 

5-29 
Vestibule 

Secondary Door 

or IRD 

Primary Door 

and/or IRD 

WICF 

Figure 5.4.2 Overhead View of Walk-In and Vestibule Entryway 

Table 5.4.30 Details for “Door Systems” Design Option 

Code Description Effectiveness $/system 

DRSTD None 0.00 $ ­

VEST Vestibule 0.98vi $1,000.00 

5.4.4.7 Display and Window Glass System Insulation Enhancement 

Display Door Enhancement 

Heat conduction through glass display doors is one of the largest energy loss components 

of a walk-in. The heat that is transferred though the doors is primarily dependent on the door 

frame material and insulation, the number and spacing of glass panes, the type of inert gas fill 

and the use of various low-emissivity coatings. DOE found that typical display doors use vinyl 

composite frames and argon gas fill. EPCA specified that, at a minimum, cooler and freezers 

display doors must utilize two and three pane doors respectively. Therefore, DOE selected these 

characteristics for the baseline options for coolers and freezers as show in Table 5.4.33 and Table 

5.4.34 below. Starting from this baseline DOE then considered additional design options DR2, 

DR3 and DR4. DR2 reflects the display door characteristics widely available for high 

performance display doors. DR3 and DR4 which incorporate multiple panes, additional coatings 

and higher performing gas fill corresponding to the mid and maximum performance technologies 

available. 

5-30 
 

 

 

 

Table 5.4.31 Details for “Display Door Enhancement” Design Option 

Cooler Freezer Cooler Freezer 

Code Description 

Overall UFactor at 75 

F [Btu/hr-fF] 

Overall UFactor at 

75 F 

[Btu/hr-fF] 

Cost [$/ft2

] Cost [$/ft2] 

DR1 Baseline Glass 0.432 0.303 $64.29 $71.43 

DR2 Enhanced 1 0.269 0.262 $88.93 $90.82 

DR3 Enhanced 2 0.123 0.123 $112.97 $129.39 

DR4 Superenhanced 0.080 0.080 $146.18 $155.21 

Due to limited availability of component manufacturer thermal performance data, DOE 

predicted the performance of the various design options using Lawrence Berkeley National Lab’s 

(LBNL) Window 5.2 program. As specified in the WICF test procedure NOPR, this is a widely 

used and verified tool for calculating performance of glass doors. 75 FR 186. The key 

assumptions, shown in Table 5.4.32, were used to generate the performance data shown in Table 

5.4.31. The predicted U-value from Window 5.2 is a full door system prediction including the 

center of glass, door frame etc. 

Table 5.4.32 Details for “Display Door Enhancement” Design Option, Window 5.2 

Assumptions used in Window 5.2 calculations: 

• Clear glass is 0.125" thick 

• Low-E glass is 0.125" thick clear glass with low-E coating 

(emissivity=0.54) 

• 0.5" thick gas layer for Argon, 0.3" for Krypton/Xenon 

• 100% purity gas filled windows 

• R-value of full thickness frame = 2.15 ft2-F-h/Btu 

Source: LBNL WINDOW 5.2 Software 

Table 5.4.33 Details for “Display Door Enhancement” Design Option, Window 5.2, Coolers 

Coolers Frame Number of 

Panes 

Glass 

type: Pane 

1 

Glass 

type: 

Pane 2 

Glass 

type: 

Pane 3 

Glass 

type: 

Pane 4 

Gas Fill 

Baseline Vinyl/Composite 2 Clear Clear - - Argon 

Enhanced 1 Vinyl/Composite 3 Low-E Clear Low-E - Argon 

Enhanced 2 Vinyl/Composite 4 Low-E Clear Clear Low-E Krypton 

Superenhanced Vinyl/Composite 4 Low-E Low-E Low-E Low-E Xenon 

5-31 
 

 

 

 

 

 

 

 

 

Table 5.4.34 Details for “Display Door Enhancement” Design Option, Window 5.2, 

Freezers 

Freezers Frame Number 

of Panes 

Glass 

type: 

Pane 1 

Glass 

type: 

Pane 2 

Glass 

type: 

Pane 3 

Glass 

type: 

Pane 4 

Gas Fill 

Baseline Vinyl/Composite 3 Clear Clear Clear - Argon 

Enhanced 1 Vinyl/Composite 3 Low-E Clear Low-E - Krypton 

Enhanced 2 Vinyl/Composite 4 Low-E Clear Clear Low-E Krypton 

Superenhanced Vinyl/Composite 4 Low-E Low-E Low-E Low-E Xenon 

Table 5.4.35 Details for “Display Door Enhancement” Design Option, Gas Fill Cost 

Incremental Cost of Krypton and Xenon 

Take Size (liquid) 64 Liters 

Cost Per Liter $23.00 $/Liter 

Cost Per Tank $1,472.00 $/Tank 

Pressure 2300 PSI 

Expanded Volume 10014 Liters 

Cost Per Liter (expanded) $ 0.15 $/Liter 

Liters Per Gap 10.36 Liters 

Cost Per Gap $1.52 $ 

Krypton, Cost Per ft2 $0.11 $ 

Xenon, Cost Per ft2 $0.21 $ 

Source: Discussion with wholesale gas companies 

5.4.4.8 Anti-sweat Heater Controls and No Anti-sweat Systems 

Anti-Sweat Heaters 

The external surface of glass display doors typically cool to temperatures below the dew 

point of the surrounding air. When this occurs, condensate or “sweat” begins to form on the 

exposed surface of the glass. It first appears as a fog, and if left unchecked, further condenses to 

droplets large enough to begin to roll and drip off the surface. The amount and rate of sweating is 

dependent on the relative humidity surrounding the walk-in and the temperature of the glass. In 

order to ensure the temperature of the glass stays above the dew point of the surroundings, 

electric resistive heater wire is installed around the frame of the door. Typical systems, 

regardless of the relative humidity, continuously power the heater wire. This means that for a 

large portion of time, the door glass is heated to temperatures far higher than necessary to remain 

above the dew point, resulting in additional electricity consumption. 

With the use of an anti-sweat heater control system that senses the relative humidity, the 

level of heating required to avoid condensate can be precisely matched to the conditions. The 

energy savings seen in practice for freezers and coolers is approximately 50 percent and 75 

percent, respectively. 

5-32 
 

 

 

 

Therefore, DOE set the baseline option of display walk-ins to not include anti-sweat 

heaters and the next design option, ASCTRL, to include their use. Since freezers operate at much 

colder temperatures than coolers, the wattage required for freezer heater wire is higher to ensure 

the appropriate door temperature is achieved. See Table 5.4.36 for details. 

In recent years the cost of anti-sweat controls has dropped significantly. A number of 

display door manufacturers now offer the controls as a standard option. A single $100 controller 

is capable of controlling up to five doors, so the average cost on a per door basis is 

approximately $20.00vii . 

As described above, sweating is a function of glass temperature and the dew point (or 

relative humidity) of the surrounding air. The external surface of the glass experiences such low 

temperatures because of the low resistivity of most glass doors. However, as the thermal 

resistance to heat transfer of the glass door increases, the glass surface temperature also 

increases. Therefore, if the glass door has high enough thermal resistivity it is possible to reduce 

or entirely eliminate the need for anti-sweat heaters. Based on manufacturer comment, DOE 

estimated that with display door option DR2, the power for heater wire could be reduced to 

1W/ft and for DR3 or DR4, the heater wire could be eliminated. 

Table 5.4.36 Details for “Anti-Sweat Heaters” Design Option 

Cooler Freezer Heater wire 

Code Description 

Passage 

Door Wire 

[W/ft] 

Passage 

Door Wire 

[W/ft] 

PTO 

Cooler 

PTO 

Freezer Cost 

ASHNC Baseline (No Controller) 5.40 8.00 0% 0% $­

ASCTRL Anti-Sweat Heater 

Controls 5.40 8.00 75% 50% $100.00 

5.4.5 Details for Refrigeration System Design Options 

Table 5.4.37 summarizes the design option codes and descriptions for each refrigeration 

system design option. Sections 5.4.5.1 through 5.4.5.8 contain details for improved technologies 

for refrigeration systems. 

5-33 
 

 

 

Table 5.4.37 Design Option Codes and Descriptions for Refrigeration Systems 

Design Option Code Description 

High-Efficiency Scroll Compressors 

HER Hermetic Compressor 

SCR Scroll Compressor 

Condenser Coil 

CD1 Baseline Coil 

CD2 Larger Coil 

Condenser Fan Motors 

PSC Permanent Split Capacitor Motors 

ECM Electronically Commutated Motors 

Evaporator Fan Blades 

EB1 Standard Evaporator Fan Blades 

EB2 Improved Evaporator Fan Blades 

Condenser Fan Blades 

CD1 Standard Condenser Fan Blades 

CD2 Improved Condenser Fan Blades 

Evaporator Coil 

EV1 Baseline Coil 

EV2 Larger Coil 

Evaporator Fan Control 

EM1 Baseline (No Control) 

EM2 Evaporator Fan Control 

Floating Head Pressure 

- Baseline (Fixed Head Pressure) 

FHP Floating Head Pressure 

Defrost Controls 

DF1 Baseline (Timed Defrost) 

DF2 Defrost Control 

5.4.5.1 High-Efficiency Scroll Compressors 

The compressor design option applies only to DC equipment classes. In consultation with 

compressor manufacturers and external design 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 scroll 

compressor. (See section 5.4.2.2 for why two-speed and variable-speed compressors were not 

considered.) Reductions in total system energy consumption are realized through a reduction in 

compressor energy consumption. 

DOE collected performance data for single-speed hermetic compressors and scroll 

compressors over a range of capacities applicable to the covered equipment. DOE then selected 

one representative hermetic compressor and one representative scroll compressor for two 

different sizes of each equipment class, representing two analytical points for a small and a large 

unit of each class. The performance data were then used to calculate the power and capacity of 

the compressors using the 10-coefficient method described in section 5.4.9.1. 

5-34 
 

Table 5.4.38 Details for "High-Efficiency Scroll Compressor" Design Option 

Class Baseline (Hermetic) Model High Efficiency (Scroll) Model 

DC.M.I – Small CS10K6E-PFV ZB10KCE-PFV 

DC.M.I – Large CS18K6E-PFV ZB19KQE-PFV 

DC.M.O – Small CS12K6E-PFV ZX15KCE-PFV 

DC.M.O – Large CS18K6E-PFV ZX21KCE-PFV 

DC.L.I – Small CF06K6E-PFV ZF06K4E-PFV 

DC.L.I – Large CF12K6E-PFV ZF11K4E-PFV 

DC.L.O – Small CF06K6E-PFV ZF06K4E-PFV 

DC.L.O – Large CF12K6E-PFV ZF11K4E-PFV 

5.4.5.2 Condenser Coil 

This design option applies only to DC equipment classes. DOE considered two 

technology levels: a standard coil and a larger coil that was sized to run at a saturated condensing 

temperature (SCT) that is cooler than that of the baseline coil. DOE calculated the temperature 

difference (TD) between the SCT and the ambient temperature, for the baseline coil. Then DOE 

considered a theoretical improved coil that ran at an SCT such that the TD was half that of a 

baseline coil. DOE chose a multiplier rather than a constant decrease because some classes of 

equipment, such as low temperature equipment, are already set to run at a smaller TD on the 

condenser. Furthermore, there are heat transfer constraints on how far the TD can be decreased. 

DOE then calculated the size of the improved coil from the baseline coil, assuming all other 

characteristics stayed the same, by using the heat transfer equation: 

Q& A = Eq. 5.1 U ×TD 

where:
 

A = face area of the coil;
 

Q& = rate of heat transfer; 

U = constant coil coefficient
 

TD = temperature difference
 

Thus, a smaller TD necessitates a larger area. DOE calculated the new area assuming 

that both the length and the width of the coil would change at the same rate. DOE then used the 

cost model to calculate the added cost of materials to produce the larger coil. Because 

compressor capacity and power consumption are directly related to SCT, reductions in the 

energy consumption are realized through an improved normalized energy consumption. Details 

of the TD multiplier are shown in Table 5.4.39. 

Table 5.4.39 Details for "Condenser Coil" Design Option 

Code Description TD Multiplier 

CD1 Baseline 1 

CD2 Improved 0.5 

5-35 
 

 

For improved condenser coils, DOE assessed the incremental increase in cost due to 

additional material cost and separately evaluated the impact on shipping cost for each dedicated 

condensing equipment class and size. The results are shown in Table 5.4.40. 

Table 5.4.40 Details for "Condenser Coil" Design Option, Continued 

Equipment Class Extra Material/Labor Cost ($) Extra Shipping Cost ($) 

DC.M.I – Small $75.77 $12.66 

DC.M.I – Large $147.32 $28.33 

DC.M.O – Small $191.22 $28.44 

DC.M.O – Large $190.80 $28.33 

DC.L.I – Small $96.40 $12.74 

DC.L.I – Large $155.99 $30.63 

DC.L.O – Small $116.59 $12.74 

DC.L.O – Large $202.33 $30.63 

5.4.5.3 Condenser Fan Motors 

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

from the refrigerant into the ambient air. The condenser fan motor design option applies only to 

the dedicated condensing equipment classes. EPCA requires that all condenser fan motors under 

1 horsepower be either ECMs (brushless DC motors), PSCs, or 3-phase. (42 U.S.C. 

6313(f)(1)(F)) Currently, DOE considers PSC motors as the minimum technology and ECMs as 

the maximum technology. DOE did not consider 3-phase motors in the engineering analysis as 

discussed in chapter 4 of the preliminary TSD. 

Error! Reference source not found.Table 5.4.41shows details for the condenser fan 

motor design option. The motor efficiency levels listed were taken from American National 

Standards Institute (ANSI)/ARI Standard 1200-2006, “Performance Rating of Commercial 

Refrigerated Display Merchandisers and Storage Cabinets,” as DOE assumed that these types of 

motors were similar in efficiency. Because condenser fan motors are outside the refrigerated 

space, efficiency improvements only impact the direct electrical consumption of the motors and 

not the heat load. 

Table 5.4.41 Details for "Condenser Fan Motor" Design Option 

Code Description Rated Power (HP) Actual Power (W) Efficiency Cost 

PSC Permanent Split Capacitor 1/6 428 29% $35.58 

ECM Brushless DC Motor 1/6 188 66% $71.29 

5.4.5.4 Evaporator and Condenser Fan Blades 

High efficiency fan blades reduce motor shaft power requirements by moving air more 

efficiently. Most evaporator and condenser fans use stamped sheet metal or plastic axial fan 

blades that are paddle-shaped. These fan blades are lightweight and inexpensive. The blades are 

typically supplied by a fan blade manufacturer and mounted to the motor by the equipment 

manufacturer. The higher efficiency blades DOE considered typically have swept fins for 

improved airflow. DOE estimated that these fan blades could increase fan efficiency by 15 

5-36 
percent for the evaporator and condenser fans. This efficiency improvement is realized as lower 

energy consumption by the fan motor. 

Figure 5.4.3 Examples of Standard Fan Bladesviii ix ,
 

Figure 5.4.4 Examples of High Efficiency Fan Bladesx,

xi 

Table 5.4.42 Details for “High Efficiency Fan Blades – Evaporator” Design Option 

Code Description Fan Power 

Multiplier 

Cost Premium 

per Fan 

EB1 Baseline 1 $­

EB2 Improved 0.85 $28.01 

Table 5.4.43 Details for “High Efficiency Fan Blades – Condenser” Design Option 

Code Description Fan Power 

Multiplier 

Cost Premium 

per Fan 

CB1 Baseline 1 $­

CB2 Improved 0.85 $18.27 

5.4.5.5 Evaporator Coil 

Similar to the condenser coil, DOE considered two technology levels for the evaporator: 

a standard coil and a larger coil that was sized to run at a saturated evaporator temperature (SET) 

(also known as saturated suction temperature, or SST) that is warmer than that of the baseline 

coil. DOE calculated the temperature difference (TD) between the SET and the walk-in’s 

5-37 
 

 

 

 

 

 

 

 

interior temperature, for the baseline coil. Then DOE considered a theoretical improved coil that 

ran at an SET that was 2 degrees warmer than that of a baseline coil. DOE chose a relatively 

small change in SET because the TD can drastically affect the humidity inside the walk-in. This 

could result in a decrease in utility for some walk-ins because of the nature of the product stored. 

For instance, fruits and flowers must be stored at a certain humidity in order to keep them fresh 

and not overdry them. In consultation with experts, DOE determined that a TD change of only 2 

degrees would not be enough to drastically change the humidity, but would be significant enough 

to result in energy savings. 

As with the condenser coil, DOE used the heat transfer equation to calculate the size of 

the improved coil from the baseline coil, assuming all other characteristics stayed the same. 

DOE calculated the new area assuming that both the length and the width of the coil would 

change at the same rate. DOE then used the cost model to calculate the added cost of materials 

to produce the larger coil. Because compressor capacity and power consumption are directly 

related to SET, reductions in the energy consumption are realized through an improved 

normalized energy consumption. Details of the TD are shown in Table 5.4.44. 

Table 5.4.44 Details for "Evaporator Coil" Design Option 

Code Description TD Reduction (°F) 

EV1 Baseline 0 

EV2 Improved 2 

As with condenser coils, for improved evaporator coils, DOE assessed the incremental 

increase in cost due to additional material cost and separately evaluated the impact on shipping 

cost for each equipment class and size. The results are shown in Table 5.4.45. 

Table 5.4.45 Details for "Evaporator Coil" Design Option, Continued 

Equipment Class Extra Material/Labor Cost ($) Extra Shipping Cost ($) 

DC.M.I – Small $38.81 $4.03 

DC.M.I – Large $51.02 $5.63 

DC.M.O – Small $27.00 $2.80 

DC.M.O – Large $36.53 $4.03 

RC.M – Small $13.56 $1.45 

RC.M – Large $26.96 $3.68 

DC.L.I – Small $27.75 $2.25 

DC.L.I – Large $27.80 $3.03 

DC.L.O – Small $16.63 $1.65 

DC.L.O – Large $20.94 $2.28 

RC.L – Small $11.34 $1.30 

RC.L – Large $23.11 $3.31 

5.4.5.6 Evaporator Fan Control 

Evaporator fan controls save energy by allowing the evaporator fans to run at variable 

speed, or cycle on and off, during periods when the compressor is off. Without fan controls, the 

evaporator fans run at a constant speed at all times unless turned off manually. The proposed test 

procedure incorporates an off-cycle evaporator fan test to determine evaporator fan energy 

consumption during a compressor-off period. The proposed test procedure measures the effect of 

5-38 
 

any fan control, with the following constraint: “controls shall be adjusted so that the greater of a 

25% duty cycle or the manufacturer default is used for measuring off-cycle fan energy. For 

variable-speed controls, the greater of 25% fan speed or the manufacturer’s default fan speed 

shall be used for measuring off-cycle fan energy. When a cyclic control is used, at least three full 

‘stir cycles’ are measured.” Because of these restrictions, the maximum energy savings that can 

be achieved is a 75% reduction in fan energy. DOE therefore set this as the energy savings 

achieved for the fan control technology option. These savings are realized as a reduction in the 

off-cycle fan energy consumption, which reduces both the direct energy consumption of the 

system and the heat contribution that must be removed. 

Table 5.4.46 Details for “Evaporator Fan Control” Design Option 

Code Description 

Off-Cycle 

Fan Power 

Multiplier 

Cost 

Premium 

EM1 Baseline 1 $­

EM2 Controlled 0.25 $300.00 

5.4.5.7 Floating Head Pressure 

The two technology levels for this design option are fixed head pressure and floating 

head pressure. Fixed head pressure involves keeping the compressor discharge pressure at a 

constantly fixed setting in order to enable operation over a variety of ambient temperatures in 

outdoor units. Generally, this is fixed at a high value in order to ensure that a sufficient amount 

of refrigerant can flow through the system, which also protects the condenser against freezing 

and maintains the necessary pressure difference across the expansion valve. However, this also 

keeps the condensing temperature fixed at a high level regardless of the ambient temperature. 

Floating head pressure utilizes a control system and sophisticated expansion valves, 

typically electronic expansion valves (EEVs), to control the flow of refrigerant and keep liquid 

refrigerant from reaching the compressor. A pressure transducer may also be wired to the 

controller for pressure and temperature sensing. With floating head pressure, the compressor 

pressure and the saturated condensing temperature (SCT) float down to a minimum at which the 

compressor can operate. This typically corresponds to an SCT of 70 degrees. Compressor 

capacity and power consumption are directly related to SCT; compressors run more efficiently at 

a lower SCT. Thus, reductions in the energy consumption due to floating head pressure are 

realized through improved normalized energy consumption. 

Table 5.4.47 Details for “Floating Head Pressure” Design Option 

Code Description Cost 

Premium 

- Fixed Head Pressure $­

FHP Floating Head Pressure $200.00 

5.4.5.8 Defrost Controls 

5-39 
 

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

duration of defrost periods. Most walk-in defrost systems without controls are scheduled for 

certain times and last for a preset duration (time-time). Various control strategies include 

scheduling defrosts at certain times and using temperature termination control (timetemperature), only starting a defrost when necessary and then running for a set duration 

(temperature-time), and starting only when necessary and using temperature termination control 

(temperature-temperature). Still other strategies involve using an adaptive learning algorithm to 

predict when a defrost will be needed. Methods of detecting when a defrost is necessary and 

when a defrost cycle should terminate include optical sensing of frost on the evaporator coil or 

measurement of refrigerant temperature and pressure at various points on the refrigeration 

equipment. 

Due to the complexity of the various control schemes, DOE did not attempt to analyze 

every one. However, in consultation with industry experts, DOE determined that without 

controls, most defrost cycles are scheduled to run more frequently and longer than necessary. 

Therefore, for the defrost control option, DOE assumed that a control strategy would result in 

half the amount of defrost power required, implemented in the energy model as a reduction by 

half in the number of defrost cycles per day. These savings are realized both as a reduction in the 

direct energy consumption of the system and a reduction in the amount of heat that must be 

removed by the system. 

Table 5.4.48 Details for “Defrost Controls” Design Option 

Code Description Cycle Divider Cost Premium 

DF1 Baseline 1 $­

DF2 Controlled 2 $185.00 

5.4.6 Baseline Specifications 

DOE defined baseline 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 the energy consumption of each equipment class. In 

conjunction with the lowest technological level of each design option, the baseline specifications 

define the energy consumption and cost of the typical lowest efficiency equipment on the 

market. DOE established baseline specifications for each of the equipment classes modeled in 

the engineering analysis by reviewing available manufacturer data, selecting several 

representative units from available manufacturer data, and then aggregating the physical 

characteristics of the selected units. This process created a representative unit for each equipment 

class with average characteristics for physical parameters (e.g., volume, wall area), and typical 

performance for energy-consuming components. Table 5.4.49 through Table 5.4.52 show the 

specifications and units that are defined for envelopes and refrigeration systems, respectively. 

5-40 
Table 5.4.49 Baseline Specifications for Envelopes, Coolers 

Equipment Class and Size ND.C - Small ND.C - Medium ND.C - Large D.C - Small D.C - Medium D.C - Large Internal Dry Bulb Temperature 35.0 35.0 35.0 35.0 35.0 35.0 

External Dry Bulb Temperature 75.0 75.0 75.0 75.0 75.0 75.0 

Internal RH 0.6 0.6 0.6 0.6 0.6 0.6 External RH 0.4 0.4 0.4 0.4 0.4 0.4 Height 7.6 9.5 12.0 6.6 7.6 7.6 

Length 10.0 12.0 25.0 6.0 10.2 80.0 

Width 8.0 20.0 30.0 6.0 7.0 15.0 

Passage Door Window Glass Area 0.9 0.9 0.9 0.0 0.0 0.0 

Display Door Width 2.5 2.5 2.5 2.5 2.5 2.5 

Display Door Height 6.3 6.3 6.3 6.3 6.3 6.3 

Passage Door Width 3.0 3.0 3.0 3.0 3.0 3.0 

Passage Door Height 7.0 7.0 7.0 7.0 7.0 7.0 

Freight Door Width 7.0 7.0 7.0 7.0 7.0 7.0 

Freight Door Height 9.0 9.0 12.0 9.0 9.0 12.0 

Number of Display Doors 0.0 0.0 0.0 3.0 8.0 50.0 

Number of Passage Doors 1.0 1.0 2.0 1.0 1.0 2.0 

Number of Freight Doors 0.0 1.0 1.0 0.0 0.0 0.0 

Total External Surface Area 433.0 1088.0 2820.0 230.0 404.2 3844.0 

Floor Area 80.0 240.0 750.0 36.0 71.4 1200.0 Total Passage Door Window Glass Area 0.9 0.9 1.8 0.0 0.0 0.0 Non-Display Door Area 21.0 84.0 126.0 21.0 21.0 42.0 Total Display Door Area 0.0 0.0 0.0 47.3 126.0 787.5 Total Passage Door Area 21.0 21.0 42.0 21.0 21.0 42.0 Total Freight Door Area 0.0 63.0 84.0 0.0 0.0 0.0 Walls, Ceiling & Non-Display Door Area 332.0 764.0 1944.0 125.8 185.8 1814.Case Gross Refrigerated Volume 606.7 2280.0 9000.0 237.0 542.6 9120.0 Number of Light Tubes/Bulbs 1 1 3 4 10 52 

Number of Circulation Fans 0 0 0 0 0 0 Walls/Floor Baseline Cost $ 2,139 $ 4,005 $ 9,921 $ 1,069 $ 1,504 $ 8,90

Total Display Door Baseline Cost $ ­ $ ­ $ ­ $ 3,038 $ 8,100 $50,62

Total Baseline Cost $ 2,139 $ 4,005 $ 9,921 $ 4,106 $ 9,604 $59,52

5-41 
Table 5.4.50 Baseline Specifications for Envelopes, Freezers 

Equipment Class and Size ND.F - Small ND.F - Medium ND.F - Large D.F - Small D.F - Medium D.F - Large Internal Dry Bulb Temperature -10.0 -10.0 -10.0 -10.0 -10.0 -10.0 

External Dry Bulb Temperature 75.0 75.0 75.0 75.0 75.0 75.0 

Internal RH 0.6 0.6 0.6 0.6 0.6 0.6 External RH 0.4 0.4 0.4 0.4 0.4 0.4 EER 6.3 6.3 6.3 6.3 6.3 6.3 Height 7.6 9.5 12.0 6.6 7.6 7.6 

Length 8.0 9.0 25.0 6.0 10.2 80.0 

Width 6.0 20.0 20.0 6.0 7.0 15.0 

Passage Door Window Glass Area 0.9 0.9 0.9 0.0 0.0 0.0 

Display Door Width 2.5 2.5 2.5 2.5 2.5 2.5 

Display Door Height 6.3 6.3 6.3 6.3 6.3 6.3 

Passage Door Width 3.0 3.0 3.0 3.0 3.0 3.0 

Passage Door Height 7.0 7.0 7.0 7.0 7.0 7.0 

Freight Door Width 7.0 7.0 7.0 7.0 7.0 7.0 

Freight Door Height 9.0 9.0 12.0 9.0 9.0 12.0 

Number of Display Doors 0.0 0.0 0.0 3.0 8.0 50.0 

Number of Passage Doors 1.0 1.0 2.0 1.0 1.0 2.0 

Number of Freight Doors 0.0 1.0 1.0 0.0 0.0 0.0 

Total External Surface Area 308.8 911.0 2080.0 230.0 404.2 3844.0 

Floor Area 48.0 180.0 500.0 36.0 71.4 1200.0 Total Passage Door Window Glass Area 0.9 0.9 1.8 0.0 0.0 0.0 Non-Display Door Area 21.0 84.0 126.0 21.0 21.0 42.0 Total Display Door Area 0.0 0.0 0.0 47.3 126.0 787.5 Total Passage Door Area 21.0 21.0 42.0 21.0 21.0 42.0 Total Freight Door Area 0.0 63.0 84.0 0.0 0.0 0.0 Walls, Ceiling & Non-Display Door Area 239.8 647.0 1454.0 125.8 185.8 1814.Case Gross Refrigerated Volume 364.8 1710.0 6000.0 237.0 542.6 9120.0 Number of Light Tubes/Bulbs 1 1 3 4 9 52 Number of Circulation Fans 0 0 0 0 0 0 Walls/Floor Baseline Cost $ 2,111 $ 5,053 $11,118 $ 1,373 $ 1,982 $16,39

Total Display Door Baseline Cost $ ­ $ ­ $ ­ $ 3,375 $ 9,000 $56,25

Total Baseline Cost $ 2,111 $ 5,053 $11,118 $ 4,748 $10,982 $72,64

5-42 
Table 5.4.51 Baseline Specifications for Refrigeration Systems, Medium Temperature 

Equipment Class and Size DC.M.I – Small DC.M.I – Large DC.M.O – Small DC.M.O – Large MC

S

Interior Temperature [F] 35 35 35 35 

Saturated Evaporator Temperature (SET) Nominal [F] 25 25 25 25 

Saturated Condenser Temperature (SCT) Nominal [F] 115 115 115 115 

Design Ambient Temperature [F] 90 90 95 95 

Nominal Evaporator Coil Capacity [Btu/h] 15,600 26,000 15,600 26,000 9

Evaporator Coil Height [in] 12.5 12.5 12.5 12.5 1

Evaporator Coil Width [in] 48.0 80.0 48.0 80.0 3

Evaporator Coil Depth [in] 4 4 4 4 

Evaporator Fan Type ECM ECM ECM ECM E

Evaporator Fan Horsepower [HP] 1/15 1/15 1/15 1/15 1

Number of Evaporator Fans [#] 3 5 3 5 

Condenser Coil Height [in] 15.0 18.0 18.0 18.0 

Condenser Coil Width [in] 16.0 30.0 30.0 30.0 

Condenser Coil Depth [in] 3 3 3 3 

Condenser Fan Type PSC PSC PSC PSC 

Condenser Fan Horsepower [HP] 1/6 1/6 1/6 1/6 

Number of Condenser Fans [#] 1 2 2 2 

Nominal Compressor Capacity [Btu/h] 15,000 26,000 15,000 24,000 

Defrost Mechanism Type - - - - 

Defrost Time per Day [hrs] - - - - 

Defrost+Drain Heater Power [W] - - - - 

5-43 
Table 5.4.52 Baseline Specifications for Refrigeration Systems, Low Temperature 

Equipment Class and Size DC.L.I – Small DC.L.I – Large DC.L.O – Small DC.L.O – Large M

S

Interior Temperature [F] -10 -10 -10 -10 

Saturated Evaporator Temperature (SET) Nominal [F] -20 -20 -20 -20 

Saturated Condenser Temperature (SCT) Nominal [F] 110 110 110 110 Design Ambient Temperature [F] 90 90 95 95 

Nominal Evaporator Coil Capacity [Btu/h] 6,000 12,000 6,000 12,000 6

Evaporator Coil Height [in] 13.5 12.5 13.5 12.5 1

Evaporator Coil Width [in] 31.9 48.0 31.9 48.0 3

Evaporator Coil Depth [in] 4 4 4 4 

Evaporator Fan Type ECM ECM ECM ECM E

Evaporator Fan Horsepower [HP] 1/15 1/15 1/15 1/15 1

Number of Evaporator Fans [#] 2 3 2 3 

Condenser Coil Height [in] 15.0 18.0 18.0 18.0 

Condenser Coil Width [in] 16.0 30.0 30.0 30.0 

Condenser Coil Depth [in] 3 3 3 3 

Condenser Fan Type PSC PSC PSC PSC 

Condenser Fan Horsepower [HP] 1/6 1/6 1/6 1/6 

Number of Condenser Fans [#] 1 2 1 2 

Nominal Compressor Capacity [Btu/h] 6,500 12,500 6,000 11,500 

Defrost Mechanism Type ELE ELE ELE ELE 

Defrost Time per Day [hrs] 1 1 1 1 

Defrost+Drain Heater Power [W] 1,656 2,756 1,656 2,756 1

5-44 
 

 

5.4.7 Non-Numerical Assumptions 

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

assumptions concerning the analysis. These include general assumptions about the analysis as 

well as specific assumptions regarding load components and design options. 

5.4.7.1 Assumptions Concerning the Envelope Energy Calculations 

The temperature and humidity inside the cooled space of the WICF and of the 

surrounding environment was considered to be constant. While a real walk-in envelope sited in 

the outdoors may consume more or less energy relative to a walk-in sited indoors, this was 

ignored in the engineering analysis for two reasons. First, the WICF test procedure does not 

account for weather effects. It compares the performance of all walk-ins, designed for both the 

indoors and outdoors, in the same manner. Secondly, accounting for large regional variation in 

weather would result in a variable standard that undermines the “level playing field” that DOE is 

attempting to protect. 

The cooled space of the walk-in was modeled as an empty space. No accounting for food 

(or other) product variation, such as type of product, rate of product turnover or product initial 

temperature was considered. Therefore the heat capacity (or thermal mass) nor the volume of 

stored products was considered which would have otherwise impacted air movement, total 

cooled air volume and transient temperatures of the cooled space. This was to eliminate 

confounding factors so that design options could be compared within the engineering analysis. 

(However, product loading was considered in the Energy Use Analysis (chapter 7 of the 

preliminary TSD) to better replicate real-world conditions.) 

If air curtains were selected as a design option in the analysis, it was assumed that the 

device would only operate for as long as a door that it was protecting was opened. Therefore, the 

door opening time exactly equals the air curtain fan motor operation time. This was used to 

calculate the associated electrical energy consumed to reduce air exchange. The majority of 

commercially available air curtains, considered by the DOE, include electronic switches that 

sense door openings as a standard option. 

All of the components were modeled as newly manufactured. Wear on gaskets, joints etc 

were not considered. Foam R-value degradation caused by water infiltration was not considered. 

However, DOE used long term thermal resistance (LTTR) values of both XPS and PU foam for 

all of the heat conduction calculations. This reflects the use of an LTTR measurement in DOE’s 

proposed test procedure for WICF. 

In previous related rulings, vacuum insulated panels have not been considered viable 

design options. However, due to recent increase in production, corresponding drop in cost and 

efforts by VIP manufacturers to break into the walk-in market by making a product that is better 

suited for panel construction, DOE considered VIPs as a design option. While they are still far 

more expensive than other options, DOE recognizes that they are technically viable and 

commercial available for use in WICF. 

5-45 
 

 

The walk-ins were modeled as simple cuboids. No unique geometries were considered 

such as L-shaped systems or other designs that have irregular external surface area to volume 

ratios. Due to the variation in design, various geometries would have made the analysis too 

complex. In addition, co-sited walk-ins or walk-ins that share a wall with another walk-in were 

not considered, again due to the vast variation in design. DOE considers the impact of this 

approach to be limited because the key parameter considered in the analysis was the total 

external surface area which is most strongly correlated with WICF energy consumption. 

Radiation heat transfer was not directly considered in the energy modeling of WICF. 

Since outdoor conditions were not considered and it was assumed that WICF are not normally 

sited near high temperature radiative heat sources such as boilers or other high heat equipment, 

this is a reasonable assumption. However, radiation is indirectly considered in the U-value 

calculations used to measure the performance of glass display doors. The Window 5.2 software 

models this form of heat transfer which is largely reduced by low emissivity coatings. 

While in practice, the frequency of door opening events would vary depending on the 

time of day and walk-in type, DOE considered the door openings to occur at regular intervals 

throughout a twenty-four hour period. This simplifying assumption ignores the transient effects 

of air infiltration on internal temperature of the walk-in among other transient phenomena. 

Because all walk-ins within a product class were compared using the same assumptions, this was 

considered a reasonable simplification. In addition, the overall impact on daily or annual energy 

consumption is believed to be limited and these assumptions reflect the values of the proposed 

WICF test procedure. 75 FR 197 

5.4.7.2 Assumptions Concerning the Refrigeration Energy Consumption 

DOE assumed that all conditions are based on new equipment tested in a controlledenvironment chamber subjected to AHRI 1250-2009, the proposed refrigeration test procedure. 

Once the test procedure is finalized, manufacturers that certify their equipment to comply with 

Federal standards will be required to test new units to this test method, which specifies certain 

ambient temperature, humidity, and other requirements. 

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

multiplex condensing systems (see chapter 4, screening analysis). 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 test procedure does not capture 

the heat added to a walk-in during a hot-gas defrost cycle. Therefore, DOE did not consider this 

technique. 

Due to the ongoing phaseout of HCFC refrigerants in the WICF industry, HFC 

refrigerants are most likely to be used in this equipment in the future. Other alternative 

refrigerants, such as ammonia, hydrocarbons, and CO2, were not considered in this analysis, as 

they are not currently used in domestically manufactured WICF refrigeration systems. 

Additionally, some of these refrigerants, including ammonia, could be limited by State and local 

building codes due to toxicity concerns. Common HFC refrigerants used in refrigeration 

equipment include R-507 and R-404A. DOE assumed that only HFC refrigerants will be utilized 

5-46 
by WICF refrigeration systems and has based its analysis solely upon equipment containing 

those refrigerants. 

DOE assumed that there are no cyclic losses associated with the refrigeration system 

operation. In steady state operation, the majority of the refrigerant charge is located in the high 

pressure side of the system. During an off-cycle, the refrigerant migrates to the evaporator, 

because the evaporator is at a lower pressure than the condenser. At the start of the next 

operating cycle, the excess refrigerant charge in the low side of the system must be transferred to 

the high side of the system to achieve steady state operation. Liquid refrigerant in the evaporator 

flows to the accumulator, the suction pressure drops to a value low enough to vaporize the liquid, 

and the compressor pumps the vapor to the condenser. This process can take several minutes, 

during which time the refrigeration system does not operate at steady state capacity. The cyclic 

losses are greater in systems having larger coil sizes as a result of the greater amount of 

refrigerant charge in such systems. Any However, because the proposed test procedure only 

measures the compressor energy consumption when the compressor is running at steady state, 

these losses are not accounted for. 

In the baseline, the head pressure of the system is fixed at a high value regardless of the 

external temperature, in order to ensure that a sufficient amount of refrigerant can flow through 

the system, which also protects the condenser against freezing and maintains the necessary 

pressure difference across the expansion valve. One of the design options is implementing 

floating head pressure, in which the refrigerant flow is dynamically controlled over a broad range 

of external temperatures. In this case, condensing temperatures lower than the temperatures of 90 

or 95 degrees necessary for a fixed-head pressure system can be utilized. However, DOE 

assumed that the limit to which the condensing temperature could float is 70 degrees. 

Compressor performance maps do not typically show data at condensing temperatures beyond 70 

degrees, and compressor performance is not guaranteed at lower temperatures. Furthermore, 

DOE assumed that for systems with floating head pressure, as the condensing temperature 

decreased with the ambient temperature, the temperature difference (TD) between the 

condensing and ambient temperature would stay the same. 

5.4.8 Numerical Constants and Assumptions 

5-47 
 

 

 

 

 

 

 

 

 

 

 

 

 

Table 5.4.53 Envelope Assumptions 

Parameter Value Units Source 

External Dry Bulb Temperature 75 F Assumed 

Cooler- Internal Dry Bulb 

Temperature 35 F Standard medium-temperature set-point, WICF 

Manufacturers 

Concrete Floor temperature, Cooler 60 F DOE WICF Proposed Test Procedure NOPR 

Concrete Floor temperature, Freezer 65 F DOE WICF Proposed Test Procedure NOPR 

Freezer- Internal Dry Bulb 

Temperature -10 F Standard low-temperature set-point, WICF 

Manufacturers 

Internal RH 60% % Assumed 

External RH 40% % Population weighted national average humidity, 

DOE analysis 

Cooler-EER 12.4 Btu/W-h Energy Efficiency Ratio based on AHRI 

Refrigeration Equipment Test Procedure 

Freezer-EER 6.3 Btu/W-h Energy Efficiency Ratio based on AHRI 

Refrigeration Equipment Test Procedure 

Daily Time Period 24 h Assumed 

Acceleration of Gravity 32.2 ft/s2

 Assumed 

LTTR-XPS 5.61 ft2

-F-h/Btu As tested by a third party laboratory 

LTTR-Polyurethane (Foam-inplace@ 2.4 lb/ft3

 density) 6.20 ft2

-F-h/Btu As tested by a third party laboratory 

External Equivalent Convective 

Film Coefficient 0.68 ft2

-F-h/Btu Assumed 

Internal Equivalent Convective Film 

Coefficient 0.25 ft2

-F-h/Btu Assumed 

Floor Equivalent Convective Film 

Coefficient 0.87 ft2

-F-h/Btu Based on Finite Element Heat Transfer Model, 

DOE Analysis 

Rated power, 2-way pressure air 

freezer relief valve heater 23 W Component Manufacturer Data 

2-way pressure air relief valve 

heater, Operation per day 24 h Component Manufacturer Data 

Average Shipping Distance to 

Distribution Center 1000 miles DOE Estimate 

Door Flow Factor 0.8 - ASHRAE Fundamentals 

Display Door Width 2.5 ft Assumed 

Display Door Height 6.3 ft Assumed 

Passage Door Width 3 ft Assumed 

Passage Door Height 7 ft Assumed 

Freight Door Width 7 ft Assumed 

Freight Door Height 9 ft Assumed 

Large Freight Door Width 7 ft Assumed 

Large Freight Door Height 12 ft Assumed 

Infiltration Parameters 

Display Doors 

Door Openings Per Day, P 72 # DOE WICF Proposed Test Procedure NOPR 

Door Open/Close Time 8 seconds DOE WICF Proposed Test Procedure NOPR 

Time Door Stands Open 0 min/day DOE WICF Proposed Test Procedure NOPR 

Passage Doors 

Door Openings Per Day, P 60 # DOE WICF Proposed Test Procedure NOPR 

Door Open/Close Time 12 seconds DOE WICF Proposed Test Procedure NOPR 

Time Door Stands Open 15 min/day DOE WICF Proposed Test Procedure NOPR 

5-48 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Freight Doors 

Door Openings Per Day, P 60 # DOE WICF Proposed Test Procedure NOPR 

Door Open/Close Time 12 seconds DOE WICF Proposed Test Procedure NOPR 

Time Door Stands Open 15 min/day DOE WICF Proposed Test Procedure NOPR 

Anti-sweat power, with display door 

option DR2 1.0 W/ft DOE Estimate 

Anti-sweat power, with display door 

option DR3 or higher 0.0 W/ft DOE Estimate 

Percentage of anti-sweat heat 

transferred into the walk-in 70 % DOE Estimate 

Freezer Passage Door Heat Wire 

Operation Time Per Day 24 h Assumed 

Control System Average Power 5 W Assumed 

Manufacturer Selling Price Mark-up 1.39 - Assumed 

Table 5.4.54 Refrigeration System Assumptions Associated with Defrost 

Constants Specified by the Test Procedure Value Units Source 

Infiltration coefficient k13 0.0001 cfm-hr/Btu Proposed Test Procedure 

Infiltration coefficient k14 3.49 cfm Proposed Test Procedure 

Humidity ratio of incoming air 0.0105 lb water/lb air Proposed Test Procedure 

Density of incoming air 0.073 lb/ft^3 Proposed Test Procedure 

Physical Properties of Materials 

Specific heat of ice 0.487 Btu/lb-R ASHRAE Handbook of 

Fundamentals, 2009 

Specific heat of water 1.00 Btu/lb-R ASHRAE Handbook of 

Fundamentals 

Latent heat of fusion of water 143.5 Btu/lb ASHRAE Handbook of 

Fundamentals 

Meltwater temperature 32 F ASHRAE Handbook of 

Fundamentals, 2009 

Other Assumptions 

Length of defrost 15 min DOE Assumption 

Amount of time between defrosts 6 h DOE Assumption 

Table 5.4.55 Refrigeration System Baseline TD Assumptions 

Class Ambient (°F) Baseline SCT (°F) Baseline TD (°F) 

DC.M.I 90 115 25 

DC.L.I 90 110 20 

DC.M.O 95 115 20 

DC.L.O 95 110 10 

5.4.9 Model Components: Envelope 

Figure 5.4.5 shows the components of the energy consumption model used in the 

engineering analysis. The model calculates energy consumption in two major subsections, heat 

load and electrical energy consumption, which are further broken out by the underlying 

components or physics. 

5-49 
 

Daily Energy 

Consumption 

[kWh/day] 

Total Heat Load 

[kWh/day] 

EER

Electric 

Energy 

Consumption 

[kWh/day] 

Heat Load 

[Btu/h] 

Legend: 

Component 

Energy 

Consumption 

[kWh/day] 

Lighting 

Energy 

Consumption 

[kWh/day] 

Anti-Sweat 

Energy 

Consumption 

[kWh/day] 

Component 

Load 

[Btu/h] 

Conduction 

Load 

[Btu/h] 

Anti-Sweat 

Heat Load 

[Btu/h] 

Lighting Heat 

Load 

[Btu/h] 

Non-Electric 

Load 

[Btu/h] 

Total Heat 

Load 

[Btu/h] 

Door Opening 

Infiltration Load 

[Btu/h] 

Steady-State 

Infiltration Load 

[Btu/h] 

Other Energy 

Consumption 

[kWh/day] 

Other Heat 

Load 

[Btu/h] 

Figure 5.4.5 Overview of Envelope Engineering Analysis Calculations 

5.4.9.1 Heat Conduction Load 

The heat transfer via conduction in the engineering analysis is broken into non-glass and 

glass related conduction. Non-glass includes the typical insulated walls, ceiling, floors and nontransparent doors. The glass calculations cover display door glass and glass inset windows. The 

heat transfer, in Btu/h, is calculated for each of these components based on the temperature 

differential between the cooled space and the surroundings, the thermal resistance of the material 

i.e. R-value of foam or the U-value of glass, and the associated surface area of that component or 

components. These properties change based on the current design option level. For example, four 

inch foam panel versus six inch foam panel. 

After completing these calculations, the total load is summed and then converted into 

units of kWh/day utilizing the assumed Energy Efficiency Ratio (EER). The EER value 

corresponds to the current walk-in type being analyzed (freezer or cooler). Further clarification 

of the use of an EER is described below. 

5.4.9.2 Energy Efficiency Ratio (EER) 

In order to estimate the associated refrigeration equipment energy consumption due to the 

envelope energy losses, DOE implemented the use of refrigeration equipment EER. The EER 

represents the energy performance of the refrigeration equipment as a ratio of units of thermal 

energy removed from the conditioned walk-in space to units of electrical energy input (to operate 

refrigeration compressors, fans etc). Therefore, this ratio represents the efficiency of the 

refrigeration equipment. DOE assumed two different EER values that correspond to medium and 

5-50 
 

low temperature refrigeration systems of 12.4 Btu/W-h and 6.3 Btu/W-hxii, respectively. 

Depending on the temperature being analyzed, the envelope engineering analysis model selects 

the appropriate EER to convert the thermal energy into units of electrical energy used. 

This “conversion” helps the load due to the envelope be more easily understood. With 

units of thermal energy in kWh, the thermal load could be directly summed with the kWh due to 

use of lights, anti-sweat heaters and other electrical components. The result is the total energy 

consumption per day in kWh. 

5.4.9.3 Infiltration Load: Steady-State 

The amount of embodied energy in an air sample is primarily a function of its 

temperature (and therefore density). This property is typically referred to as the enthalpy in any 

thermodynamic system (such as a walk-in cooler or freezer). The required amount of energy 

needed to remove heat from the air is calculated as the difference between the enthalpy of air 

entering the refrigerated space and enthalpy of the air inside the refrigerated space. This 

calculation is commonly used when designing walk-ins and typically uses dry-bulb and wet-bulb 

temperatures. In the engineering analysis the difference between the infiltrating and exfiltrating 

air, per unit cubic foot, is calculated using the functional relationship between temperature and 

enthalpy. 

Then using the estimated infiltration rate per unit surface area of the walk-in the thermal 

energy consumption, in units of Btu/h, is directly calculated. As with the conduction load, this 

thermal energy is converted into units of kWh/day using the appropriate EER value. 

5.4.9.4 Infiltration Load: Door Opening 

The heat load due to door openings is calculated in an identical manner as the steadystate infiltration calculations using the enthalpy difference of the exchanged air. In order to 

calculate the volume of air exchanged per door opening, DOE used equations developed by 

ASHRAExiii. With known air properties, door geometry and assumptions about door opening 

frequency, duration, the number of doors and the effectiveness of infiltration reduction devices, 

the volume of air exchanged for each unique door opening event is computed. The assumptions 

change with various design options. For example, the infiltration reduction effectiveness changes 

depending if a strip curtain or air curtain is in place or a display door is being opened versus a 

large freight door. As for other thermal energy calculations the total load in Btu/h is then 

converted into kWh/day using the EER. 

5.4.9.5 Anti-Sweat and Other Heater Wire Electrical Load 

Resistive heater wire is rated in units of W/ft. For a given door the perimeter length is 

calculated and multiplied by the wire rating to compute the total electrical load per door. The 

amount of time per day that the wire is powered is calculated using the assumed percent time off 

(PTO) if an anti-sweat controller is selected or not. In addition the rated power of the heater wire 

changes based on the design option level of the display door. With total wattage and operation 

time per day, the total kWh/day is then directly calculated. 

5-51 
 

 

5.4.9.6 Lighting Electrical Load 

The lighting electrical load is calculated in an identical manner as the anti-sweat systems. 

Using the rated power of the light and assumptions about PTO based on the current control 

system design option, the kWh/day from lights is computed. 

5.4.9.7 Other Electrical Devices 

As with the previous devices, the device rated power such as the heated by-directional 

pressure relief valve used in walk-in freezers or the power use of the control system hardware is 

multiplied by the hours of use per day to get the total kWh/day consumption. 

5.4.9.8 Additional Heat Load Due to Electrical Device Waste Heat 

Using the total energy consumption of all electrical devices sited inside the walk-in (air 

curtain power, for example, is not included because they are mounted external to the refrigerated 

space of the walk-in) an associated additional heat load is calculated. This thermal load is 

converted using the EER into an effective extra compressor load due to the operation of these 

electrical devices. 

The energy consumption attributed to all components is totaled to compute the full 

product incremental energy consumptions for up to fifteen unique design option levels. The 

incremental cost of each design option is also totaled in order to plot the cost-efficiency curves 

for each product class and size analysis point (small, medium and large). The final costefficiency curve displays the design options ordered by relative cost-effectiveness. 

5.4.10 Model Components: Refrigeration 

The energy consumption model analytically calculates energy consumption using the 

same methodology as the proposed test procedure. In the proposed test procedure, the 

refrigeration system is tested under certain conditions to determine steady state capacity and 

power. Then an assumed non-refrigeration load attributed to the envelope is calculated. This 

methodology assumes that the refrigeration system is sized to the expected load, allowing 

refrigeration systems to be compared with each other even when the tester does not know the 

characteristics of the envelope with which the refrigeration system will ultimately be paired. 

From the steady state power, the capacity, and the expected load profile, the annual energy 

consumption can be calculated. 

DOE’s ultimate metric that it chose for expressing the performance of the refrigeration 

system is normalized energy consumption; that is, the total annual energy consumption divided 

by the net capacity of the system. DOE chose to measure normalized energy consumption 

instead of total energy consumption because the annual energy consumption depends partly on 

the capacity of the system, which is used to determine the load factors or duty cycles. Some 

design options increase the capacity, which would tend to reduce the energy consumption by 

allowing lower duty cycles. However, under the proposed test procedure, a system with a higher 

capacity would be assumed to have a larger non-refrigeration envelope load, which could 

increase the duty cycle. To account for these competing effects, DOE normalized the energy 

5-52 
 

 

 

   

   

   

     

     

     

   

     

     

         

   

     

   

     

   

consumption by capacity. This rewards the design options that increase the efficiency of the 

refrigeration system: not the ones that save more net energy, but the ones that save more energy 

for their size. 

Error! Reference source not found.Figure 5.4.6 presents a schematic showing the 

components in the energy consumption model for dedicated condensing systems. For indoor 

systems, the test procedure assumes that the ambient temperature does not change, and therefore 

the energy consumption does not change from day to day. In this case, the energy consumption 

per day is multiplied by 365 to get annual energy consumption. For outdoor systems, a yearly 

temperature profile is assumed by the proposed test procedure, which lists the number of hours in 

each temperature “bin,” a range of 5 degrees. In this case, the net capacity and system power are 

tested at 3 test temperatures, and then calculated for all the other temperature bins using linear 

interpolation. Then the annual energy consumption is calculated by summing the energy 

consumption for each temperature bin multiplied by the number of hours in the bin. 

Normalized Energy

Consumption

((MWh/year)/(kBtu/h))

Net Capacity (Btu/h)

Gross Capacity (Btu/h)

On‐Cycle Evaporator Fan

MotorHeat Load (Btu/h)

Energy Consumption

(Wh/year)

On‐Cycle SystemPower

(W)

CompressorPower(W)

On‐Cycle Evaporator Fan

Power(W)

Condenser Fan Power

(W)

Off‐Cycle Evaporator Fan

Power(W) Defrost Power(W) Load Factors

Non‐Refrigeration Load

(Btu/h)

Off‐Cycle Evaporator Fan

Heat Load (Btu/h)

DefrostHeat Load

(Btu/h)

NetCapacity (Btu/h)

Figure 5.4.6 Energy Consumption Model for Dedicated Condensing Systems 

5-53 
 

 

 

5.4.10.1 Net Capacity 

The net capacity is calculated as the gross capacity of the compressor, less the heat given 

off by the evaporator fans when the compressor is running. Defrost heat is not considered 

because it is measured with a separate test, and would not be accounted for in the test procedure 

during the test of net capacity. The gross compressor capacity 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 

capacity, power, mass flow, current, and efficiency. The coefficients are derived for each of 

these parameters as a function of SET and SCT. Compressor coefficients, or tabulated empirical 

data (from which coefficients can be derived), are available from compressor manufacturers. The 

gross capacity is determined from the published coefficients, the SET, and the SCT. 

5.4.10.2 On-Cycle System Power 

The on-cycle system power is the sum of the compressor power, the on-cycle evaporator 

fan power, and the condenser fan power. Similar to the capacity, the compressor power is 

determined from the published compressor coefficients, the SET, and the SCT. 

5.4.10.3 Load Factors 

 The load factors represent the fraction of the time that the compressor is running at both 

a “high load” period and a “low load” period. The high-load period corresponds to the time 

during the day when the walk-in experiences a high heat load due to product being stored in the 

walk-in, employees entering and leaving, etc. The low-load period corresponds to the time 

during the day when the walk-in is not being accessed, and experiences a low heat load: night, 

off-business hours, etc. Per the proposed test procedure, 1/3 of the time is experienced at a high 

load and 2/3 at a low load. The corresponding load factors, LFH (load factor at high load) and 

LFL (load factor at low load) are calculated from the heat load on the walk-in at a high and low 

period respectively (including non-refrigeration heat load, evaporator fan heat load, and defrost 

heat load), and the net capacity of the refrigeration system to reject this load. This determines 

how frequently the compressor must run at a high and low period.

 (if , ) Eq. 5.2

 (if , ) Eq. 5.3 

where: 

WLH is the heat load on the walk-in at a high period 

WLL is the heat load on the walk-in at a low period

 qss is the net capacity. 

5-54 
 

 

WLH and WLL include all heat loads on the walk-in: non-refrigeration heat load, 

evaporator fan heat load, and defrost heat load: 

Eq.5.4 

Eq.5.5 

where: 

BLH and BLL are the non-refrigeration heat load at a high and low period, respectively,

 EFcomp,off is the evaporator fan motor power in W (multiplied by 3.412 Btu/h/W to get 

heat load,

 Qdf is the defrost heat load. 

(The on-cycle evaporator fan motor heat is not included in this equation because it is 

already accounted for in the net capacity.) 

The non-refrigeration heat loads are derived from the net capacity and, for outdoor units, 

an assumed temperature profile. As discussed above, this is because the methodology assumes 

that the refrigeration system is sized to the expected load, allowing refrigeration systems to be 

compared with each other even when the tester does not know the characteristics of the envelope 

that the refrigeration system will ultimately be paired with. 

Figure 5.4.7 presents a schematic showing the components in the energy consumption 

model for unit coolers connected to multiplex condensing systems. The model is similar, except 

the power attributed to the unit cooler is calculated by assuming a certain efficiency, or EER, for 

the multiplex system. In this case, the EER is assumed to be constant throughout the year, so 

energy consumption per day is multiplied by 365 to get annual energy consumption. 

The default EER values are contained in the proposed test procedure. The test procedure 

provides tables of EER values for both medium and low temperature systems. The EER values 

are expressed in Btu/Wh, as a function of adjusted dew point temperature. The test procedure 

provides that the adjusted dew point temperature for a medium temperature system shall be 19  ̊F 

and shall -26  ̊F for a low temperature system, unless the unit cooler is rated at a suction dew 

point other than 19  ̊F for a refrigerator or -26  ̊F for a freezer, in which case the adjusted dew 

point value shall be 2  ̊F less than the unit cooler rating suction dew point. (cite) 

5-55 
   

   

     

   

       

   

     

   

     

   

   

   

   

       

   

     

     

   

 

Normalized Energy

Consumption

((MWh/year)/(kBtu/h))

NetCoil

Capacity (Btu/h)

Gross CoilCapacity

(Btu/h)

Energy Consumption

(Wh/year)

On‐Cycle System

Power(W)

Off‐Cycle Evaporator

Fan Power(W)

DefrostPower(W) Load Factors

On‐Cycle Evaporator

Fan MotorHeat Load

(Btu/h)

NetCoil Capacity

(Btu/h)

On‐Cycle Evaporator

FanHeat Load (Btu/h)

On‐Cycle Evaporator

Fan Power(W)

EER of Multiplex

System

Non‐Refrigeration

Load (Btu/h)

Off‐Cycle Evaporator

FanHeat Load (Btu/h)

DefrostHeat Load

(Btu/h)

Net Capacity (Btu/h)

Figure 5.4.7 Energy Consumption Model for Unit Coolers Connected to Multiplex 

Condensing Systems
 

5.5 COST-EFFICIENCY CURVES 

Below are the cost-efficiency curves for the envelope and refrigeration equipment, 

respectively. 

As explained in section 5.4.10, DOE’s ultimate metric that it chose for expressing the 

performance of the refrigeration system is normalized energy consumption; that is, the total 

annual energy consumption divided by the net capacity of the system. Likewise, DOE divided 

the price by the net capacity at each efficiency level. One notable observation for some 

equipment classes is that for a few efficiency levels above the baseline, the estimated cost per 

unit energy consumption appears to decrease. This indicates that for these efficiency levels, 

although the absolute price of the unit increases, the capacity also increases at a faster rate, so the 

price per capacity decreases. 

5-56 
5.5.1 Envelope Cost-Efficiency Curves 

Table 5.5.1 Cost-Efficiency Data for the ND.C. Small Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 5.18 $2,224 $3,358 Baseline 

L1 2.99 $2,315 $3,484 L0 + SC 

L2 2.74 $2,349 $3,531 L1 + LED 

L3 1.91 $2,600 $3,940 L2 + FLR2 

L4 1.81 $2,673 $4,054 L3 + TCK2 

L5 1.80 $2,682 $4,067 L4 + XC 

L6 1.68 $2,792 $4,237 L5 + TCK3 

L7 1.64 $2,841 $4,309 L6 + FLR3 

L8 1.49 $3,033 $4,607 L7 + TCK4 

L9 1.39 $3,226 $4,904 L8 + TCK5 

L10 1.15 $4,226 $6,294 L9 + VEST 

L11 0.96 $6,224 $8,921 L10 + INSH1 

L12 0.87 $7,345 $10,479 L11 + VIP 

L13 0.83 $7,869 $11,206 L12 + ATG 

$0 

$2,000 

$4,000 

$6,000 

$8,000 

$10,000 

$12,000 

0.0 2.0 4.0 6.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.1 Cost-Efficiency Curve for the ND.C. Equipment Class [Small, Number of
 

Doors: Display, Passage, and Freight (0,1,0)]
 

5-57 
Table 5.5.2 Cost-Efficiency Data for the ND.C. Medium Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 11.50 $4,164 $6,476 Baseline 

L1 6.13 $4,527 $6,981 L0 + SC 

L2 5.88 $4,561 $7,028 L1 + LED 

L3 5.85 $4,576 $7,049 L2 + XC 

L4 4.38 $5,330 $8,291 L3 + FLR2 

L5 4.14 $5,498 $8,551 L4 + TCK2 

L6 3.86 $5,750 $8,941 L5 + TCK3 

L7 3.73 $5,896 $9,159 L6 + FLR3 

L8 3.38 $6,339 $9,841 L7 + TCK4 

L9 3.13 $6,782 $10,523 L8 + TCK5 

L10 2.55 $8,782 $13,303 L9 + VEST 

L11 2.10 $13,381 $19,361 L10 + INSH1 

L12 1.87 $15,961 $22,947 L11 + VIP 

L13 1.76 $17,285 $24,788 L12 + ATG 

$0 

$5,000 

$10,000 

$15,000 

$20,000 

$25,000 

$30,000 

0.0 5.0 10.0 15.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.2 Cost-Efficiency Curve for the ND.C. Equipment Class [Medium, Number of 

Doors: Display, Passage, and Freight (0,1,1)] 

5-58 
Table 5.5.3 Cost-Efficiency Data for the ND.C. Large Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 23.55 $10,316 $16,069 Baseline 

L1 14.27 $10,862 $16,827 L0 + SC 

L2 13.53 $10,962 $16,967 L1 + LED 

L3 13.45 $10,986 $17,000 L2 + XC 

L4 12.88 $11,414 $17,655 L3 + TCK2 

L5 12.19 $12,056 $18,637 L4 + TCK3 

L6 9.80 $14,411 $22,541 L5 + FLR2 

L7 9.42 $14,868 $23,227 L6 + FLR3 

L8 9.22 $15,118 $23,574 L7 + CS2 

L9 8.36 $16,246 $25,296 L8 + TCK4 

L10 7.74 $17,373 $27,017 L9 + TCK5 

L11 7.67 $17,573 $27,295 L10 + CS3 

L12 6.73 $20,573 $31,465 L11 + VEST 

L13 6.28 $24,020 $36,257 L12 + ATG 

L14 5.18 $35,722 $51,745 L13 + INSH1 

L15 4.62 $42,285 $60,868 L14 + VIP 

$0 

$10,000 

$20,000 

$30,000 

$40,000 

$50,000 

$60,000 

$70,000 

0.0 5.0 10.0 15.0 20.0 25.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.3 Cost-Efficiency Curve for the ND.C. Equipment Class [Large, Number of 

Doors: Display, Passage, and Freight (0,2,1)] 

5-59 
Table 5.5.4 Cost-Efficiency Data for the D.C. Small Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 34.65 $4,248 $6,036 Baseline 

L1 28.53 $4,348 $6,175 

L0 + 

ASCTRL 

L2 23.40 $4,708 $6,675 L1 + LED 

L3 19.56 $5,004 $7,086 L2 + SC 

L4 13.69 $6,168 $8,704 L3 + DR2 

L5 8.56 $7,204 $10,144 L4 + DR3 

L6 8.03 $7,317 $10,326 L5 + FLR2 

L7 7.16 $7,567 $10,673 L6 + CS2 

L8 7.12 $7,595 $10,719 L7 + TCK2 

L9 7.07 $7,636 $10,787 L8 + TCK3 

L10 5.44 $9,206 $12,969 L9 + DR4 

L11 5.43 $9,212 $12,978 L10 + XC 

L12 5.41 $9,234 $13,010 L11 + FLR3 

L13 5.35 $9,307 $13,129 L12 + TCK4 

L14 5.31 $9,380 $13,249 L13 + TCK5 

L15 5.23 $10,137 $14,210 L14 + INSH1 

$0 

$2,000 

$4,000 

$6,000 

$8,000 

$10,000 

$12,000 

$14,000 

$16,000 

0.0 10.0 20.0 30.0 40.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.4 Cost-Efficiency Curve for the D.C. Equipment Class [Small, Number of 

Doors: Display, Passage, and Freight (3,1,0)] 

5-60 
Table 5.5.5 Cost-Efficiency Data for the D.C. Medium Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 85.84 $9,913 $14,028 Baseline 

L1 69.52 $10,073 $14,250 

L0 + 

ASCTRL 

L2 60.76 $10,383 $14,681 L1 + CS2 

L3 54.15 $11,019 $15,565 L2 + SC 

L4 47.74 $11,919 $16,817 L3 + LED 

L5 32.09 $15,024 $21,133 L4 + DR2 

L6 18.42 $17,893 $25,120 L5 + DR3 

L7 17.64 $18,117 $25,485 L6 + FLR2 

L8 17.58 $18,158 $25,553 L7 + TCK2 

L9 17.57 $18,167 $25,566 L8 + XC 

L10 17.50 $18,228 $25,668 L9 + TCK3 

L11 13.13 $22,413 $31,486 L10 + DR4 

L12 13.09 $22,457 $31,550 L11 + FLR3 

L13 13.01 $22,565 $31,728 L12 + TCK4 

L14 12.94 $22,673 $31,906 L13 + TCK5 

L15 12.83 $23,791 $33,317 L14 + INSH1 

$0 

$5,000 

$10,000 

$15,000 

$20,000 

$25,000 

$30,000 

$35,000 

0.0 20.0 40.0 60.0 80.0 100.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.5 Cost-Efficiency Curve for the D.C. Equipment Class [Medium, Number of 

Doors: Display, Passage, and Freight (8,1,0)] 

5-61 
Table 5.5.6 Cost-Efficiency Data for the D.C. Large Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 409.07 $62,175 $88,642 Baseline 

L1 363.04 $63,325 $90,240 L0 + CS2 

L2 331.01 $66,916 $95,231 L1 + SC 

L3 297.67 $71,596 $101,737 L2 + LED 

L4 199.83 $91,002 $128,712 L3 + DR2 

L5 114.43 $108,932 $153,634 L4 + DR3 

L6 114.32 $108,960 $153,673 L5 + XC 

L7 113.80 $109,359 $154,304 L6 + TCK2 

L8 109.75 $113,127 $160,551 L7 + FLR2 

L9 82.44 $139,284 $196,909 L8 + DR4 

L10 81.81 $139,882 $197,859 L9 + TCK3 

L11 81.19 $140,614 $198,957 L10 + FLR3 

L12 80.43 $141,667 $200,616 L11 + TCK4 

L13 79.87 $142,719 $202,275 L12 + TCK5 

L14 79.84 $142,919 $202,553 L13 + CS3 

L15 79.22 $147,623 $209,091 L14 + ATG 

$0 

$50,000 

$100,000 

$150,000 

$200,000 

$250,000 

0.0 100.0 200.0 300.0 400.0 500.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.6 Cost-Efficiency Curve for the D.C. Equipment Class [Large, Number of
 

Doors: Display, Passage, and Freight (50,2,0)]
 

5-62 
Table 5.5.7 Cost-Efficiency Data for the ND.F. Small Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 25.67 $2,347 $3,484 Baseline 

L1 13.12 $2,458 $3,638 L0 + SC 

L2 12.82 $2,491 $3,685 L1 + LED 

L3 12.52 $2,544 $3,767 L2 + TCK2 

L4 12.16 $2,623 $3,891 L3 + TCK3 

L5 12.12 $2,631 $3,902 L4 + XC 

L6 12.01 $2,660 $3,945 L5 + FLR2 

L7 11.56 $2,799 $4,161 L6 + TCK4 

L8 11.48 $2,829 $4,204 L7 + FLR3 

L9 11.15 $2,968 $4,420 L8 + TCK5 

L10 10.26 $3,428 $5,060 L9 + AC 

L11 9.69 $4,871 $6,950 L10 + INSH1 

L12 9.39 $5,681 $8,076 L11 + VIP 

L13 9.27 $6,053 $8,593 L12 + ATG 

L14 8.99 $7,053 $9,983 L13 + VEST 

L15 8.98 $7,303 $10,330 L14 + CS2 

$0 

$2,000 

$4,000 

$6,000 

$8,000 

$10,000 

$12,000 

0.0 10.0 20.0 30.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.7 Cost-Efficiency Curve for the ND.F. Equipment Class [Small, Number of 

Doors: Display, Passage, and Freight (0,1,0)] 

5-63 
Table 5.5.8 Cost-Efficiency Data for the ND.F. Medium Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 55.25 $5,818 $8,821 Baseline 

L1 24.40 $6,262 $9,437 L0 + SC 

L2 24.10 $6,295 $9,484 L1 + LED 

L3 24.00 $6,309 $9,503 L2 + XC 

L4 23.15 $6,452 $9,724 L3 + TCK2 

L5 22.13 $6,665 $10,055 L4 + TCK3 

L6 21.70 $6,775 $10,218 L5 + FLR2 

L7 20.44 $7,150 $10,797 L6 + TCK4 

L8 20.15 $7,260 $10,961 L7 + FLR3 

L9 17.86 $8,180 $12,239 L8 + AC 

L10 16.95 $8,555 $12,818 L9 + TCK5 

L11 15.33 $12,450 $17,941 L10 + INSH1 

L12 14.51 $14,634 $20,977 L11 + VIP 

L13 13.84 $16,634 $23,757 L12 + VEST 

L14 13.47 $17,742 $25,297 L13 + ATG 

L15 13.46 $17,992 $25,645 L14 + CS2 

$0 

$5,000 

$10,000 

$15,000 

$20,000 

$25,000 

$30,000 

0.0 20.0 40.0 60.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.8 Cost-Efficiency Curve for the ND.F. Equipment Class [Medium, Number of 

Doors: Display, Passage, and Freight (0,1,1)] 

5-64 
Table 5.5.9 Cost-Efficiency Data for the ND.F. Large Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 105.04 $13,130 $19,978 Baseline 

L1 51.78 $13,796 $20,903 L0 + SC 

L2 51.54 $13,817 $20,932 L1 + XC 

L3 50.65 $13,917 $21,072 L2 + LED 

L4 48.82 $14,237 $21,564 L3 + TCK2 

L5 46.61 $14,717 $22,302 L4 + TCK3 

L6 45.42 $15,022 $22,759 L5 + FLR2 

L7 42.69 $15,865 $24,050 L6 + TCK4 

L8 38.63 $17,245 $25,968 L7 + AC 

L9 37.83 $17,550 $26,425 L8 + FLR3 

L10 35.87 $18,393 $27,715 L9 + TCK5 

L11 35.60 $18,643 $28,063 L10 + CS2 

L12 34.25 $21,183 $31,593 L11 + ATG 

L13 34.16 $21,383 $31,871 L12 + CS3 

L14 30.67 $30,135 $43,437 L13 + INSH1 

L15 28.88 $35,044 $50,260 L14 + VIP 

$0 

$10,000 

$20,000 

$30,000 

$40,000 

$50,000 

$60,000 

0.0 50.0 100.0 150.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.9 Cost-Efficiency Curve for the ND.F. Equipment Class [Large, Number of 

Doors: Display, Passage, and Freight (0,2,1)] 

5-65 
Table 5.5.10 Cost-Efficiency Data for the D.F. Small Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 79.22 $5,016 $7,127 Baseline 

L1 68.74 $5,116 $7,266 L0 + ASCTRL 

L2 46.66 $5,476 $7,767 L1 + SC 

L3 40.46 $5,836 $8,267 L2 + LED 

L4 40.29 $5,864 $8,313 L3 + TCK2 

L5 34.76 $6,780 $9,586 L4 + DR2 

L6 24.70 $8,503 $11,981 L5 + DR3 

L7 24.49 $8,544 $12,049 L6 + TCK3 

L8 23.42 $8,794 $12,397 L7 + CS2 

L9 23.34 $8,816 $12,429 L8 + FLR2 

L10 23.31 $8,823 $12,438 L9 + XC 

L11 23.06 $8,896 $12,558 L10 + TCK4 

L12 19.57 $10,116 $14,253 L11 + DR4 

L13 19.52 $10,138 $14,285 L12 + FLR3 

L14 19.33 $10,211 $14,404 L13 + TCK5 

L15 17.84 $12,051 $16,962 L14 + AC 

$0 

$2,000 

$4,000 

$6,000 

$8,000 

$10,000 

$12,000 

$14,000 

$16,000 

$18,000 

0.0 20.0 40.0 60.0 80.0 100.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.10 Cost-Efficiency Curve for the D.F. Equipment Class [Small, Number of 

Doors: Display, Passage, and Freight (3,1,0)] 

5-66 
Table 5.5.11 Cost-Efficiency Data for the D.F. Medium Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 170.22 $11,510 $16,301 Baseline 

L1 142.26 $11,670 $16,523 L0 + ASCTRL 

L2 104.31 $12,446 $17,602 L1 + SC 

L3 94.77 $12,756 $18,033 L2 + CS2 

L4 87.80 $13,566 $19,159 L3 + LED 

L5 73.05 $16,010 $22,556 L4 + DR2 

L6 72.81 $16,051 $22,624 L5 + TCK2 

L7 45.97 $20,751 $29,157 L6 + DR3 

L8 45.93 $20,760 $29,170 L7 + XC 

L9 45.64 $20,821 $29,272 L8 + TCK3 

L10 45.47 $20,865 $29,336 L9 + FLR2 

L11 45.11 $20,972 $29,514 L10 + TCK4 

L12 35.82 $24,225 $34,035 L11 + DR4 

L13 35.71 $24,269 $34,100 L12 + FLR3 

L14 35.45 $24,376 $34,278 L13 + TCK5 

L15 32.94 $28,516 $40,032 L14 + AC 

$0 

$5,000 

$10,000 

$15,000 

$20,000 

$25,000 

$30,000 

$35,000 

$40,000 

$45,000 

0.0 50.0 100.0 150.0 200.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.11 Cost-Efficiency Curve for the D.F. Equipment Class [Medium, Number of 

Doors: Display, Passage, and Freight (8,1,0)] 

5-67 
Table 5.5.12 Cost-Efficiency Data for the D.F. Large Equipment Class 

Efficiency 

Level 

Daily 

Energy 

Use 

[kWh/day] 

MPC 

Mfg. 

Cost 

[$] 

MSP 

Mfg. 

Price 

[$] 

Design 

Option 

L0 811.05 $79,357 $113,532 Baseline 

L1 755.37 $80,507 $115,131 L0 + CS2 

L2 571.53 $84,888 $121,220 L1 + SC 

L3 571.09 $84,916 $121,259 L2 + XC 

L4 530.78 $89,597 $127,765 L3 + LED 

L5 438.61 $104,870 $148,995 L4 + DR2 

L6 270.88 $134,245 $189,826 L5 + DR3 

L7 268.73 $134,644 $190,460 L6 + TCK2 

L8 266.13 $135,243 $191,410 L7 + TCK3 

L9 263.28 $135,975 $192,508 L8 + FLR2 

L10 260.07 $137,027 $194,167 L9 + TCK4 

L11 202.02 $157,356 $222,424 L10 + DR4 

L12 200.11 $158,088 $223,523 L11 + FLR3 

L13 197.80 $159,140 $225,182 L12 + TCK5 

L14 197.60 $159,340 $225,460 L13 + CS3 

L15 195.10 $164,044 $231,998 L14 + ATG 

$0 

$50,000 

$100,000 

$150,000 

$200,000 

$250,000 

0.0 200.0 400.0 600.0 800.0 1000.0 

Manufacturer Selling Price [$] 

Daily Energy Consumption [kWh/day] 

Figure 5.5.12 Cost-Efficiency Curve for the D.F. Equipment Class [Large, Number of
 

Doors: Display, Passage, and Freight (50,2,0)]
 

5-68 
5.5.2 Refrigeration Cost-Efficiency Curves
 

Table 5.5.13 Cost-Efficiency Data for the DC.M.I Equipment Class (Small)
 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 1.96 $1,923 $163 $2,710 $229 -

L1 1.53 $1,999 $137 $2,828 $194 L0 + CD2 

L2 1.46 $2,038 $133 $2,886 $189 L1 + EV2 

L3 1.33 $2,109 $138 $2,985 $195 L2 + ECM 

L4 1.08 $2,409 $158 $3,402 $223 L3 + EM2 

L5 1.06 $2,427 $159 $3,427 $224 L4 + CB2 

L6 1.03 $2,511 $163 $3,544 $230 L5 + EB2 

L7 0.98 $2,505 $193 $3,535 $273 L6 + SCR 

$0 

$50 

$100 

$150 

$200 

$250 

$300 

0.0 0.5 1.0 1.5 2.0 2.5 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.13 Cost-Efficiency Curve for the DC.M.I Equipment Class (Small) 

5-69 
Table 5.5.14 Cost-Efficiency Data for the DC.M.I Equipment Class (Large) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 1.87 $2,613 $124 $3,696 $176 -

L1 1.79 $2,664 $121 $3,772 $171 L0 + EV2 

L2 1.41 $2,812 $105 $4,006 $149 L1 + CD2 

L3 1.26 $2,954 $110 $4,204 $157 L2 + ECM 

L4 1.02 $3,254 $121 $4,621 $172 L3 + EM2 

L5 1.01 $3,291 $123 $4,672 $174 L4 + CB2 

L6 0.97 $3,431 $127 $4,866 $180 L5 + EB2 

L7 0.94 $3,705 $153 $5,247 $217 L6 + SCR 

$0 

$50 

$100 

$150 

$200 

$250 

0.0 0.5 1.0 1.5 2.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.14 Cost-Efficiency Curve for the DC.M.I Equipment Class (Large) 

5-70 
Table 5.5.15 Cost-Efficiency Data for the DC.M.O Equipment Class (Small) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 1.59 $2,194 $154 $3,102 $217 -

L1 1.51 $2,221 $147 $3,142 $208 L0 + EV2 

L2 1.25 $2,412 $137 $3,436 $195 L1 + CD2 

L3 0.87 $2,612 $149 $3,714 $211 L2 + FHP 

L4 0.81 $2,683 $153 $3,813 $217 L3 + ECM 

L5 0.73 $2,992 $157 $4,242 $223 L4 + SCR 

L6 0.67 $3,076 $161 $4,359 $228 L5 + EB2 

L7 0.50 $3,376 $176 $4,776 $249 L6 + EM2 

$0 

$50 

$100 

$150 

$200 

$250 

$300 

0.0 0.5 1.0 1.5 2.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.15 Cost-Efficiency Curve for the DC.M.O Equipment Class (Small) 

5-71 
Table 5.5.16 Cost-Efficiency Data for the DC.M.O Equipment Class (Large) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 1.70 $2,689 $128 $3,801 $181 -

L1 1.63 $2,725 $124 $3,856 $175 L0 + EV2 

L2 1.46 $2,999 $117 $4,237 $165 L1 + SCR 

L3 1.22 $3,190 $113 $4,530 $160 L2 + CD2 

L4 0.88 $3,390 $120 $4,808 $170 L3 + FHP 

L5 0.64 $3,690 $130 $5,225 $185 L4 + EM2 

L6 0.56 $3,833 $135 $5,423 $192 L5 + ECM 

L7 0.55 $3,869 $137 $5,474 $193 L6 + CB2 

L8 0.52 $4,009 $141 $5,669 $199 L7 + EB2 

$0 

$50 

$100 

$150 

$200 

$250 

0.0 0.5 1.0 1.5 2.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.16 Cost-Efficiency Curve for the DC.M.O Equipment Class (Large) 

5-72 
Table 5.5.17 Cost-Efficiency Data for the MC.M.I Equipment Class (Small) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 1.08 $ 729 $ 79 $1,029 $112 -

L1 1.00 $ 739 $ 80 $1,043 $113 L0 + EB2 

L2 0.98 $ 753 $ 81 $1,063 $115 L1 + EV2 

L3 0.76 $1,053 $114 $1,480 $160 L2 + EM2 

$0 

$20 

$40 

$60 

$80 

$100 

$120 

$140 

$160 

$180 

0.0 0.5 1.0 1.5 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.17 Cost-Efficiency Curve for the MC.M.I Equipment Class (Small) 

5-73 
Table 5.5.18 Cost-Efficiency Data for the MC.M.I Equipment Class (Large) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 1.04 $1,617 $ 55 $2,288 $ 77 -

L1 0.97 $1,648 $ 55 $2,329 $ 78 L0 + EB2 

L2 0.95 $1,674 $ 56 $2,371 $ 79 L1 + EV2 

L3 0.74 $1,974 $ 66 $2,788 $ 93 L2 + EM2 

$0 

$10 

$20 

$30 

$40 

$50 

$60 

$70 

$80 

$90 

$100 

0.0 0.5 1.0 1.5 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.18 Cost-Efficiency Curve for the MC.M.I Equipment Class (Large) 

5-74 
Table 5.5.19 Cost-Efficiency Data for the DC.L.I Equipment Class (Small) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 6.60 $1,723 $349 $2,424 $491 -

L1 6.14 $1,751 $323 $2,465 $455 L0 + EV2 

L2 5.37 $2,046 $290 $2,876 $408 L1 + SCR 

L3 4.58 $2,143 $279 $3,022 $394 L2 + CD2 

L4 4.14 $2,214 $288 $3,122 $407 L3 + ECM 

L5 4.00 $2,270 $293 $3,199 $413 L4 + EB2 

L6 3.95 $2,288 $295 $3,225 $416 L5 + CB2 

L7 3.77 $2,473 $319 $3,482 $449 L6 + DF2 

L8 3.53 $2,773 $358 $3,899 $503 L7 + EM2 

$0 

$100 

$200 

$300 

$400 

$500 

$600 

0.0 2.0 4.0 6.0 8.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.19 Cost-Efficiency Curve for the DC.L.I Equipment Class (Small) 

5-75 
Table 5.5.20 Cost-Efficiency Data for the DC.L.I Equipment Class (Large) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 6.01 $2,199 $222 $3,111 $314 -

L1 5.67 $2,226 $208 $3,153 $294 L0 + EV2 

L2 4.78 $2,382 $189 $3,400 $270 L1 + CD2 

L3 4.17 $2,672 $197 $3,802 $280 L2 + SCR 

L4 3.67 $2,814 $207 $4,000 $295 L3 + ECM 

L5 3.56 $2,898 $212 $4,117 $301 L4 + EB2 

L6 3.50 $2,935 $214 $4,168 $304 L5 + CB2 

L7 3.34 $3,120 $228 $4,425 $323 L6 + DF2 

L8 3.15 $3,420 $250 $4,842 $354 L7 + EM2 

$0 

$50 

$100 

$150 

$200 

$250 

$300 

$350 

$400 

0.0 2.0 4.0 6.0 8.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.20 Cost-Efficiency Curve for the DC.L.I Equipment Class (Large) 

5-76 
Table 5.5.21 Cost-Efficiency Data for the DC.L.O Equipment Class (Small) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 5.81 $1,778 $360 $2,501 $506 -

L1 5.39 $1,795 $331 $2,525 $466 L0 + EV2 

L2 4.67 $2,090 $296 $2,936 $416 L1 + SCR 

L3 4.13 $2,207 $293 $3,111 $414 L2 + CD2 

L4 3.75 $2,278 $303 $3,210 $427 L3 + ECM 

L5 2.88 $2,478 $329 $3,488 $464 L4 + FHP 

L6 2.76 $2,534 $333 $3,566 $469 L5 + EB2 

L7 2.72 $2,553 $336 $3,592 $473 L6 + CB2 

L8 2.44 $2,853 $375 $4,009 $527 L7 + EM2 

L9 2.27 $3,038 $400 $4,266 $561 L8 + DF2 

$0 

$100 

$200 

$300 

$400 

$500 

$600 

0.0 2.0 4.0 6.0 8.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.21 Cost-Efficiency Curve for the DC.L.O Equipment Class (Small) 

5-77 
Table 5.5.22 Cost-Efficiency Data for the DC.L.O Equipment Class (Large) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 5.23 $2,281 $230 $3,225 $326 -

L1 4.93 $2,302 $215 $3,257 $304 L0 + EV2 

L2 4.21 $2,591 $208 $3,659 $293 L1 + SCR 

L3 3.74 $2,793 $210 $3,971 $298 L2 + CD2 

L4 2.85 $2,993 $225 $4,249 $319 L3 + FHP 

L5 2.49 $3,136 $236 $4,447 $334 L4 + ECM 

L6 2.39 $3,220 $240 $4,564 $340 L5 + EB2 

L7 2.35 $3,257 $243 $4,614 $344 L6 + CB2 

L8 2.20 $3,442 $256 $4,872 $363 L7 + DF2 

L9 1.96 $3,742 $279 $5,289 $394 L8 + EM2 

$0 

$50 

$100 

$150 

$200 

$250 

$300 

$350 

$400 

$450 

0.0 2.0 4.0 6.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.22 Cost-Efficiency Curve for the DC.L.O Equipment Class (Large) 

5-78 
Table 5.5.23 Cost-Efficiency Data for the MC.L.I Equipment Class (Small) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 3.35 $ 706 $118 $ 996 $166 -

L1 3.28 $ 718 $120 $1,014 $169 L0 + EV2 

L2 3.13 $ 774 $128 $1,091 $180 L1 + EB2 

L3 2.93 $ 959 $158 $1,349 $222 L2 + DF2 

L4 2.68 $1,259 $208 $1,766 $291 L3 + EM2 

$0 

$50 

$100 

$150 

$200 

$250 

$300 

$350 

0.0 1.0 2.0 3.0 4.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.23 Cost-Efficiency Curve for the MC.L.I Equipment Class (Small) 

5-79 
Table 5.5.24 Cost-Efficiency Data for the MC.L.I Equipment Class (Large) 

Efficiency 

Level* 

Normalized 

Daily Energy 

Consumption 

[(kWh/day)/ 

(kBtu/h)] 

Manufacturer 

Production 

Cost (MPC) 

[$] 

Normalized 

MPC 

[$/(kWh/day)] 

Manufacturer 

Selling Price 

(MSP) 

[$] 

Normalized 

MSP 

[$/(kBtu/h)] 

Option 

L0 2.96 $1,596 $ 60 $2,257 $ 85 -

L1 2.90 $1,619 $ 61 $2,293 $ 87 L0 + EV2 

L2 2.74 $1,804 $ 68 $2,550 $ 96 L1 + DF2 

L3 2.53 $2,104 $ 80 $2,967 $112 L2 + EM2 

L4 2.47 $2,272 $ 85 $3,200 $120 L3 + EB2 

$0 

$20 

$40 

$60 

$80 

$100 

$120 

$140 

0.0 1.0 2.0 3.0 4.0 

Normalized Manufacturer Selling Price

[$/(kBtu/h)] 

Normalized Daily Energy Consumption 

[(kWh/day)/(kBtu/h)] 

Figure 5.5.24 Cost-Efficiency Curve for the MC.L.I Equipment Class (Large) 

5-80 
 

REFERENCES 

i

 American Metals Market, http://www.amm.com/. 

ii U.S. Department of Labor, Bureau of Labor Statistics, Producer Price Indices, http://www.bls.gov/ppi/.
 iii Other insulation products such as expanded polystyrene, polyisocyanurate and polyurethane board stocks are also
 

used in WICF construction.
 iv Downing, C.C. and Meffert, W.A, “Effectiveness of Cold-Storage Door Infiltration Protective Devices,” 3726 

(RP-645), ASHRAE Transactions: Research, 1993 

v

 Downing, C.C. and Meffert, W.A, “Effectiveness of Cold-Storage Door Infiltration Protective Devices,” 3726 

(RP-645), ASHRAE Transactions: Research, 1993, p. 359

vi Downing, C.C. and Meffert, W.A, “Effectiveness of Cold-Storage Door Infiltration Protective Devices,” 3726 

(RP-645), ASHRAE Transactions: Research, 1993, p. 359

vii Cost estimated based on DOE discussions with glass door component manufacturers and anti-sweat controller 

companies

viii http://blog.etundra.com/wp-content/Media/2009/09/23418.jpg
 ix http://www.azpartsmaster.com/images/catalog/ashop/a31185.jpg
 x

 Taizhou Koman Motor Products Co., Ltd
 xi Rosenberg Ventilatoren GmbH
 xii The EER values were assumed based on values specified in the WICF Test procedure NOPR
 xiii Gosney and Olama (1975), ASHRAE Refrigeration Handbook, 12.4
 

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