CHAPTER 3. MARKET AND TECHNOLOGY ASSESSMENT 

TABLE OF CONTENTS 

3.1 INTRODUCTION ............................................................................................................ 3-1
 

3.2 MARKET ASSESSMENT ............................................................................................... 3-1
 

3.2.1 Manufacturers and Market Share............................................................................ 3-1
 

3.2.2 Small Businesses ..................................................................................................... 3-3
 

3.2.3 Trade Associations .................................................................................................. 3-4
 

3.2.4 Industry Consolidation............................................................................................ 3-6
 

3.2.5 Equipment Classes.................................................................................................. 3-6
 

3.2.5.1 Refrigeration ............................................................................................ 3-6
 

3.2.5.2 Envelope .................................................................................................. 3-8
 

3.2.6 Equipment Lifetimes............................................................................................... 3-8
 

3.2.6.1 Refrigeration ............................................................................................ 3-8
 

3.2.6.2 Envelope .................................................................................................. 3-9
 

3.2.6.3 Used or Refurbished Equipment .............................................................. 3-9
 

3.2.7 Shipments .............................................................................................................. 3-10
 

3.2.8 Barriers to Efficiency Improvements.................................................................... 3-10
 

3.2.9 Regulatory and Non-Regulatory Initiatives .......................................................... 3-11
 

3.2.9.1 California Energy Commission.............................................................. 3-11
 

3.2.9.2 Other U.S. States.................................................................................... 3-12
 

3.2.9.3 Australia & New Zealand ...................................................................... 3-12
 

3.2.9.4 Japan ...................................................................................................... 3-13
 

3.2.10Market Performance Data ..................................................................................... 3-13
 

3.2.10.1 Envelope ................................................................................................ 3-13
 

3.2.10.2 Refrigeration .......................................................................................... 3-15
 

3.3 TECHNOLOGY ASSESSMENT ................................................................................... 3-19
 

3.3.1 Technologies and Designs Relevant to All Envelope Equipment Classes ........... 3-20
 

3.3.1.1 Wall, Ceiling, and Floor Insulation........................................................ 3-20
 

3.3.1.2 Door Gaskets.......................................................................................... 3-20
 

3.3.1.3 Panel Interface Systems ......................................................................... 3-20
 

3.3.1.4 Electronic Lighting Ballasts and High-Efficiency Lighting .................. 3-20
 

3.3.1.5 Occupancy Sensors ................................................................................ 3-21
 

3.3.1.6 Automatic Door Opening and Closing Systems .................................... 3-21
 

3.3.1.7 Non-Penetrative Internal Racks and Shelving ....................................... 3-21
 

3.3.1.8 Air Curtains............................................................................................ 3-21
 

3.3.1.9 Strip Curtains ......................................................................................... 3-22
 

3.3.1.10 Refrigeration System Override .............................................................. 3-22
 

3.3.1.11 Air and Water Infiltration Sensors ......................................................... 3-22
 

3.3.1.12 Humidity Sensors................................................................................... 3-23
 

3.3.1.13 Heat Flux Sensors .................................................................................. 3-23
 

3.3.1.14 Vestibule Entryways .............................................................................. 3-23
 

3.3.1.15 Revolving Doors .................................................................................... 3-23
 

3.3.1.16 Fiber Optic Natural Lighting ................................................................. 3-23
 

3.3.1.17 Energy Storage Systems ........................................................................ 3-24
 

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3.3.2 Technologies and Designs Relevant to Display Envelopes Only......................... 3-24
 

3.3.2.1 Display and Window Glass System Insulation Performance ................ 3-24
 

3.3.2.2 Anti-sweat Heater Controls.................................................................... 3-24
 

3.3.2.3 Non-Electric Anti-sweat Systems .......................................................... 3-25
 

3.3.2.4 No Anti-sweat Systems .......................................................................... 3-25
 

3.3.2.5 Automatic Insulation Deployment Systems........................................... 3-25
 

3.3.3 Technologies and Designs Relevant to All Refrigeration Equipment Classes ..... 3-25
 

3.3.3.1 Evaporator and Condenser Fan Blades.................................................. 3-25
 

3.3.3.2 Improved Evaporator and Condenser Coils ........................................... 3-26
 

3.3.4 Technologies and Designs Relevant to Dedicated Condensing Refrigeration 

Systems Only ........................................................................................................ 3-26
 

3.3.4.1 Ambient Subcooling .............................................................................. 3-26
 

3.3.4.2 Higher-Efficiency Fan Motors ............................................................... 3-26
 

3.3.4.3 Automatic Evaporator Fan Shut-Off...................................................... 3-27
 

3.3.4.4 Evaporator Fan Control.......................................................................... 3-27
 

3.3.4.5 Higher-Efficiency Compressors............................................................. 3-27
 

3.3.5 Technologies and Designs Relevant to Low Temperature Refrigeration Systems 

Only....................................................................................................................... 3-27
 

3.3.5.1 Hot Gas Defrost ..................................................................................... 3-27
 

3.3.5.2 Defrost Controls..................................................................................... 3-28
 

3.3.6 Technologies and Designs Relevant to Outdoor Refrigeration Systems Only..... 3-28
 

3.3.6.1 Floating Head Pressure .......................................................................... 3-28
 

3.3.6.2 Economizer Cooling .............................................................................. 3-29
 

LIST OF TABLES 

Table 3.2.1 Manufacturers of Walk-in Equipment (Envelope Only) ......................................... 3-2
 

Table 3.2.2 Manufacturers of Walk-in Equipment (Refrigeration Only) ................................... 3-2
 

Table 3.2.3 Manufacturers of both Envelope and Refrigeration ................................................ 3-2
 

Table 3.2.4 Equipment Classes for Refrigeration Equipment .................................................... 3-7
 

Table 3.2.5 Equipment Classes for Envelopes............................................................................ 3-8
 

Table 3.2.6 Lifetime of Refrigeration Equipment ...................................................................... 3-9
 

Table 3.2.7 Value of Shipments of Walk-In Coolers and Freezers (in millions) ..................... 3-10
 

Table 3.2.8 Estimated Shipments of Envelope & Refrigeration Equipment, 1998-2009 ......... 3-10
 

Table 3.2.9 Requirements for Walk-ins Sold in California ...................................................... 3-12
 

Table 3.2.10 Summary of Walk-in Cooler and Freezer Data Compiled by NRCan ................ 3-13
 

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CHAPTER 3. MARKET AND TECHNOLOGY ASSESSMENT
 

3.1 INTRODUCTION 

This chapter details the market and technology assessments that the U.S. Department of 

Energy (DOE) has carried out in support of the energy conservation standards rulemaking for 

walk-in coolers and freezers (WICF or walk-ins). Prior to 2007, walk-in coolers and freezers 

had never before been the subject of energy conservation regulations at the federal level. 

This chapter consists of two sections: the market assessment and the technology 

assessment. The goal of the market assessment is to develop a qualitative and quantitative 

characterization of the WICF industry and market structure, based on publicly available 

information as well as data and information submitted by manufacturers and other stakeholders. 

Issues that are addressed include manufacturer characteristics and market shares, existing 

regulatory and non-regulatory efficiency improvement initiatives, equipment classes, and trends 

in equipment markets and characteristics. The goal of the technology assessment is to develop a 

preliminary list of technologies that could be used to improve the efficiency of walk-in coolers 

and freezers. 

As discussed in Chapter 2 of the preliminary Technical Support Document (TSD), DOE 

is considering setting standards separately for the two overall components of a walk-in: the 

envelope and the refrigeration system. DOE’s market research found that the majority of small 

manufacturers in the WICF industry manufacture either envelope or refrigeration, but not both. 

On the other hand, DOE found that large manufacturers or parent companies tend to manufacture 

both envelope and refrigeration. Accordingly, DOE conducted the MTA by examining 

manufacturers of envelope only, refrigeration only, and both envelope and refrigeration. 

3.2 MARKET ASSESSMENT 

The following market assessment identifies domestic manufacturers of walk-in 

equipment, manufacturer market share, the manufacturer trade association, regulatory programs, 

and non-regulatory initiatives; defines equipment classes; provides historical shipment data and 

equipment lifetime estimates; and summarizes market performance data. 

3.2.1 Manufacturers and Market Share 

DOE identified 47 manufacturers of walk-in envelopes (listed in Table 3.2.1), 8 

manufacturers of walk-in refrigeration systems (listed in Table 3.2.2), and 9 manufacturers of 

both envelopes and refrigeration (listed in Table 3.2.3). Parent companies are shown in 

parentheses. 

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Table 3.2.1 Manufacturers of Walk-in Equipment (Envelope Only) 

*Advanced Refrigeration 

Technology 

*Dade Engineering Corporation 

a.k.a. Daeco 

*Refrigeration Gaskets of Texas, 

Inc. 

*Aircooler Corporation *Duracold Refrigeration 

Manufacturing Company *Refrigerator Manufacturers, Inc. 

*American Cold Storage, Inc *General Restaurant Equipment Co, 

Inc. *Rudy's Commercial Refrigeration 

*American Cooler Technologies Hussmann Corporation (IngersollRand) *Snowman Cooler LLC 

*American Insulated Panel Co. *Imperial Manufacturing *Southeast Cooler Corporation 

*Amerikooler, Inc *Kool Star (Standex International 

Corporation) *Storflex Fixture Corporation 

*Arctic Industries, Inc Kysor Panel Systems (Manitowoc) *Superior Commercial Coolers, Inc 

*Artic Temp Inc Leer Limited Partnership (Dexter 

Apache Holdings, Inc.) *T.M.P. Company, Inc. (Tafco) 

*Bush Refrigeration *Louisville Cooler Manufacturing 

Company *T.O. DeVilbiss Manufacturing Co. 

Carroll Coolers Inc. (Dexter Apache 

Holdings, Inc.) *Mr. Winter/Isopanel ThermalRite (Rainey Road LLC) 

*Chrysler & Koppin Company *National Cooler (Dover 

Corporation) *Thermo-Kool/Mid-South Ind, Inc 

*Clark Manufacturing (Southern 

Stainless Equipment Co.) *North Star Refrigerator Co., Inc *U.S. Cooler Company, Inc. (Craig 

Industries) 

*Commercial Cooling (PAR 

Engineering, Inc.) *Pacific Refrigerator Company *W.A. Brown & Son, Inc. 

*Cool Solutions Panel 

Manufacturing LLC. *Penn Refrigeration Service Co. *Worldwide Refrigeration 

*Crown Tonka Walk-ins (Rainey 

Road LLC) *Polar King International, Inc. *Yenlin Li Refrigeration Company 

*Custom Cooler, Inc. *Polar Panels Mfg. LLC 

*Small business manufacturer 

Table 3.2.2 Manufacturers of Walk-in Equipment (Refrigeration Only) 

*Century Refrigeration (RAE 

Corporation) Krack (Ingersoll Rand) Tecumseh Products Company 

Heat Transfer Products Group a.k.a. 

Russell (United Technologies 

Corporation) 

*LRC Coil Company a.k.a. S&S 

Refrigeration Corp 

Trenton Refrigeration Products 

(National Refrigeration and Air 

Conditioning Products Inc.) 

Heatcraft Refrigeration Products, 

LLC (Lennox International) *Peerless of America, Inc. 

*Small business manufacturer 

Table 3.2.3 Manufacturers of both Envelope and Refrigeration 

*Advance Energy Technologies, 

Inc. *Bally Refrigerated Boxes, Inc Kolpak (Manitowoc) 

*Airdyne Refrigeration (ARI 

Industries) 

Harford Duracool, LLC 

(Manitowoc) 

Master-Bilt Products (Standex 

International Corporation) 

*American Panel Corporation *International Cold Storage (Rainey 

Road LLC) 

Nor-Lake, Inc. (Standex 

International Corporation) 

*Small business manufacturer 

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As illustrated in these tables, the walk-in market is characterized by a large number of 

small companies and a small number of large companies. In general, the large companies tend to 

be part of public corporations while the small companies tend toward private ownership. For 

small companies, DOE gathered company information including revenues from Hoovers. DOE 

also analyzed financial information for all publicly traded manufacturers of walk-ins by 

examining SEC 10-k reports. The total walk-in market, including envelope and/or refrigeration 

equipment, is valued at roughly $800 million to $1 billion in annual revenue. No single company 

controls the market, although the several large companies together represent roughly half of the 

annual revenue. This diversity reflects the wide range of end-users that make up the customer 

base: larger manufacturers tend to serve chain and brand name stores in the grocery, 

supermarket, and convenience store markets while smaller manufacturers may be preferred by 

regional non-chain convenience and grocery stores. 

DOE estimated that the envelope-only manufacturers have combined total revenues of 

approximately $367 million. DOE is aware that there may be additional small envelope-only 

manufacturers not listed in any of the tables above or in publicly available documents or 

websites. 

Though DOE identified several companies that only manufacture refrigeration 

equipment, the market is dominated by a few large players. United Technologies Corporate 

(UTC), Lennox International Inc (LII), and Tecumseh make up a majority of sales in the market 

through their subsidiary brands. Those brands include Russell, Heatcraft, and Tecumseh Cool 

Products, respectively. Public data for both Lennox International Inc and Tecumseh provided 

revenue for commercial refrigeration, and public data for United Technologies Corporate 

provided revenue for cooling equipment in general, including air conditioning. Thus, DOE was 

unable to determine the exact percentage of WICF market share attributed to each company 

because the revenue data does not explicitly break out revenue from WICF refrigeration sales. 

Likewise, of the manufacturers that manufacture both refrigeration and envelopes, the 

market was dominated by the large companies: Ingersoll-Rand (subsidiary brands are Hussman 

and Krack), Standex International Corporation (subsidiary brands are Master-Bilt and Nor-Lake), 

and Manitowoc (subsidiary brands are Harford Duracool, Kysor Panel, and Kolpak). These large 

companies tended to break out food service equipment in their public revenues reports, but 

similarly to refrigeration equipment, this could include types of equipment other than walk-ins, 

such as commercial refrigerated display cases, reach-ins, and refrigerated beverage vending 

machines. Walk-in specific revenues were embedded in these data within the public revenue 

reports, but were not broken out specifically. 

3.2.2 Small Businesses 

DOE is considering the possibility that small businesses would be particularly impacted 

by the promulgation of energy conservation standards for walk-ins. The Small Business 

Administration (SBA) lists small business size standards for industries as they are described in 

the North American Industry Classification System (NAICS). The size standard for an industry is 

the largest that a for-profit concern can be in that industry and still qualify as a small business for 

Federal Government programs. These size standards are generally expressed in terms of the 

average annual receipts or the average employment of a firm. DOE matched walk-in coolers and 

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freezers to NAICS code 333415, Air-Conditioning and Warm Air Heating Equipment and 

Commercial and Industrial Refrigeration Equipment Manufacturing, which has a size standard of 

750 employees. DOE realizes that this code may be appropriate only for manufacturers of walkin refrigeration systems and may not apply to manufacturers of walk-in envelopes. DOE also 

realizes that a different metric than size (for instance, annual receipts) may be more appropriate 

for characterizing small manufacturers of walk-in equipment. DOE will consult with the SBA in 

the next stage of the rulemaking to determine the best way to characterize small manufacturers in 

the walk-in industry. 

Manufacturers classified as small businesses according to the NAICS code assumed for 

the industry are indicated in Table 3.2.1 through Table 3.2.3 with a *. 

DOE will study the potential impacts on these small businesses in detail during the 

manufacturer impact analysis, which will be conducted as a part of the notice of proposed 

rulemaking analysis. 

3.2.3 Trade Associations 

There is no single unifying trade organization representing manufacturers of WICF. 

Rather, the industry is segmented by equipment type and end use. Several refrigeration system 

manufacturers are represented by a single association. Also, some walk-in manufacturers belong 

to a trade association that represents manufacturers of foodservice equipment. No association 

represents manufacturers of envelopes specifically, although several organizations represent 

manufacturers of different types of foam used in WICF envelopes. 

The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) is one of the trade 

associations representing walk-in cooler and freezer manufacturers.i

 AHRI primarily represents 

refrigeration manufacturers, although some of these companies also make the envelopes used in 

WICF. Manufacturers of walk-ins and walk-in components with membership in AHRI include: 

‐ Carrier Corporation 

‐ Emerson Climate Technologies 

‐ Heatcraft Refrigeration Products, LLC 

‐ Heat Transfer Product Group (also known as Russell) 

‐ Hill PHOENIX 

‐ Honeywell International, Inc. 

‐ Hussmann Corporation 

‐ Kysor/Warren 

‐ Master-Bilt Products 

As an organization, AHRI is subdivided into divisions that represent various parts of the 

refrigeration market. One of these is the Commercial Refrigerator Manufacturers Division 

(CRMD). Originally founded in 1933 as a separate trade association, CRMD was established 

within AHRI with the purpose of developing and implementing a certification program for 

commercial refrigerators, commercial freezers, and commercial refrigerator-freezers. Technical 

activities of CRMD include: 

3-4 
 

 

‐ Harmonization of international equipment standards; 

‐ Development of industry performance standards for commercial refrigeration equipment; 

‐ Updating of industry guidelines for retail store fixture installation, design, energy
 

conservation, electronic case controls, and specifications for equipment installation; 

‐ Maintaining liaison with refrigerant suppliers and government agencies on 

environmentally acceptable chlorofluorocarbon (CFC) alternatives; and 

‐ Providing input to government agencies concerning regulations affecting the industry. 

The North American Association of Food Equipment Manufacturers (NAFEM) 

represents manufacturers of foodservice equipment. Several WICF manufacturers who sell 

equipment to the foodservice industry belong to NAFEM, including: 

‐ American Panel Corporation 

‐ Arctic Industries, Inc.
 

‐ Bally Refrigerated Boxes, Inc.
 

‐ Hussmann Corporation
 

‐ Imperial Manufacturing 

‐ International Cold Storage
 

‐ Kolpak Walk-ins 

‐ Kool Star 

‐ Leer, Inc.
 

‐ Master-Bilt Products 

‐ Nor-Lake, Inc.
 

‐ Penn Refrigeration Service Corporation
 

‐ Polar King International, Inc.
 

‐ Tafco – TMP Company
 

‐ ThermalRite
 

‐ Thermo-Kool/Mid-South Industries Inc.
 

‐ U.S. Cooler Company
 

The envelope segment of the walk-in industry has no single organization serving in an 

umbrella role. Reflecting the diversity of products available, several trade associations represent 

manufacturers of specific foam types within the WICF industry. 

‐ Polyurethane Manufacturers Association (PMA, www.pmahome.org) comprised of 

numerous suppliers, distributors and contractors of polyurethane foam insulation. 

‐ Extruded Polystyrene Foam Association (XPSA, www.xpsa.com) comprised of Dow 

Chemical, Owens Corning, and Pactiv, the main manufacturers of extruded polystyrene 

foam insulation. 

‐ Spray Polyurethane Foam Alliance (SPFA, www.sprayfoam.org) comprised of 

contractors, chemical manufacturers, and distributors of spray polyurethane foam 

insulation. Chemical manufacturers include: BASF Polyurethane Foam Enterprises LLC, 

Gaco Western, Honeywell, Huntsman Polyurethanes. 

3-5 
 

‐ Polyisocyanurate Insulation Manufacturers Association (PIMA, www.polyiso.org) 

comprised of manufacturers, suppliers, and brand relabelers associated with the 

polyisocyanurate foam insulation industry. Arkema, Inc. is a member. 

3.2.4 Industry Consolidation 

The consolidation of major manufacturers through mergers and acquisitions is an 

industry trend. In some cases consolidation serves to expand vertical reach, such as the 

acquisition of an envelope manufacturer by a refrigeration manufacturer, while in other cases 

consolidation creates companies with a more dominant market share in a similar manufacturing 

process. For example: 

‐ In 1995, commercial refrigeration manufacturer Manitowoc acquired walk-in 

manufacturer Kolpak. 

‐ In 2000, Hill PHOENIX (Dover Corporation) acquired National Cooler Corporation, a 

manufacturer of walk-in coolers and freezers. 

‐ In 2000, refrigeration and envelope manufacturer Hussmann was acquired by Ingersoll 

Rand. 

‐ In 2003, Standex International Corporation acquired Nor-Lake, which manufacturers 

walk-in envelopes. In 2005, the company acquired Kool Star, a refrigeration 

manufacturer for walk-in end uses. Standex International also owns Master-Bilt, a major 

refrigeration and envelope manufacturer. 

‐ In 2008, Manitowoc went on to buy Enodis, PLC in 2008. Enodis owned another 

envelope manufacturer, Kysor Panel Systems.
 

‐ In 2009, Rainey Road, LLC, owner of CrownTonka Walk-ins and ThermalRite, 

purchased another envelope manufacturer, International Cold Storage, from Carrier 

Commercial Refrigeration, Inc, (Carrier Corporation). 

3.2.5 Equipment Classes 

3.2.5.1 Refrigeration 

Refrigeration systems of walk-in coolers and freezers can be divided into various 

equipment classes categorized by key physical characteristics that affect the efficiency of the 

equipment: the operating temperature, the location of the walk-in (i.e., indoors or outdoors) and 

the type of condensing unit (i.e., whether the system has a dedicated condensing unit or is 

connected to a multiplex system). 

The condensing unit type has a significant impact on utility and energy use. DOE is 

considering two classes of equipment associated with the condensing unit type: dedicated 

condensing (DC) systems and multiplex condensing (MC) systems. In a dedicated condensing 

system, there is only one condensing unit (consisting of one or more compressors and 

condensers) that serves a single walk-in. In a multiplex condensing system, the unit cooler inside 

the walk-in envelope is connected via a refrigerant line to a system consisting of several 

3-6 
 

 

 

condensers and compressors in parallel; the set of condensers and compressors serves both the 

walk-in and other equipment, which may include other walk-ins or other types of refrigeration 

equipment such as reach-ins. Walk-in units that are connected to a large supermarket compressor 

rack fall into this category. Multiplex condensing equipment is typically more efficient than 

dedicated condensing equipment because it uses compressors of varying capacity and cycles 

them on and off as needed to avoid excess capacity in operation. Compressor racks and 

condensers of multiplex systems are outside the scope of this rulemaking. 

For dedicated condensing units only, the location of the condensing unit, indoors or 

outdoors, affects the characteristics with regard to energy consumption. Indoor units are assumed 

to operate at a consistent ambient temperature, while outdoor units are assumed to experience 

varying temperatures throughout the year. The proposed test procedure accounts for this 

variation by requiring outdoor condensing units to be tested at three ambient temperatures. This 

gives credit for certain energy-saving technologies that may allow the compressor to use less 

energy at lower ambient temperatures. Therefore, DOE intends to create separate classes for 

refrigeration equipment with indoor (I) and outdoor (O) condensing units. 

The operating temperature for walk-ins determines whether the equipment is a 

refrigerator (medium or high operating temperature) or a freezer (low operating temperature). 

Because different types of merchandise require different temperatures (e.g., chilled or frozen), 

operating temperature is a necessary class distinction. Furthermore, EPCA specifically divides 

walk-in equipment into coolers (above 32 °F) and freezers (at or below 32 °F). The larger 

temperature differences and thermodynamic behavior of refrigerants means that equipment with 

lower operating temperatures runs less efficiently than equipment with higher operating 

temperatures. Thus, DOE is considering separate classes for refrigeration equipment that is 

medium-temperature (M), operating above 32 °F; and low-temperature (L), operating at or below 

32 °F. 

Using all combinations of condensing unit types, location and temperature, 6 equipment 

classes are possible for walk-in cooler or freezer refrigeration systems. DOE also developed a 

lettering system to simplify discussion of equipment classes. The lettering designation for a 

particular equipment class consists of the lettering abbreviations for the condenser type, location 

and temperature, separated by periods. A complete list of equipment classes with lettering 

designations is shown in Table 3.2.4. 

Table 3.2.4 Equipment Classes for Refrigeration Equipment 

Condensing Type* Operating 

Temperature Condenser Location Class 

Multiplex 

Medium - MC.M 

Low ­ MC.L 

Dedicated 

Medium 

Indoor 

DC.M.I 

Low DC.L.I 

Medium 

Outdoor 

DC.M.O 

Low DC.L.O 

*Note: For each of the six equipment classes, two analysis points will be used, 

corresponding to small and large representative units. 

3-7 
3.2.5.2 Envelope 

Likewise, DOE also divided envelopes into different equipment classes, as shown in 

Table 3.2.5. 

DOE is considering creating separate equipment classes for display (D) and non-display 

(ND) walk-ins (that is, walk-ins with and without glass). Glass is necessary for displaying 

products, but also has a significant effect on energy consumption because of substantial heat loss 

through the glass. To achieve significant energy savings, transparent glass doors could be 

replaced by standard foam insulated doors. However, this directly impacts the utility of this 

product, which is specifically designed to ensure an unobstructed view through the doors. This 

requirement means that walk-ins with glass doors are inherently less energy efficient. Therefore, 

to avoid unfairly penalizing display walk-ins by requiring the same energy standard to be met for 

both display and non-display, DOE created a separate class for non-display products. 

DOE also intends to create separate classes for coolers (C) and freezers (F). Coolers and 

freezers have different insulation requirements under EPCA. Like display and non-display 

products, freezer and coolers have distinct design requirements; for example, freezers must have 

door heater wires to prevent entry doors from freezing closed. In addition, EPCA specifically 

divides walk-in equipment into coolers (above 32 °F) and freezers (at or below 32 °F). 

Outdoor units were not considered as a separate product class since there are limited 

design options available to reduce energy consumption. Manufacturers typically sell indoor units 

as outdoor units by including roofing or other weatherization systems to prevent rain from 

entering panel-to-panel interfaces. In addition, the proposed WICF test procedure does not 

provide a means of testing variation in due external temperature for outdoor units. 75 FR 186. 

Table 3.2.5 Equipment Classes for Envelopes 

Display Type* Operating Temperature Class 

Non-Display 

Cooler ND.C. 

Freezer ND.F. 

Display 

Cooler D.C. 

Freezer D.F. 

*Note: For each of the four equipment classes, three analysis points will be used, 

corresponding to small, medium, and large representative units. 

3.2.6 Equipment Lifetimes 

3.2.6.1 Refrigeration 

DOE reviewed available literature and consulted with experts on walk-in refrigeration 

equipment in order to establish typical equipment lifetimes. The literature and individuals 

consulted estimated a wide range of typical equipment lifetimes, as shown in Table 3.2.6. 

3-8 
 

 

 

 

 

 

A 2008 report by The Freedonia Group suggested that custom-made walk-in refrigeration 

units are typically used by the food production/distribution sectors. As these units are not seen by 

consumers but are made for durability, efficiency and dependability, there is little attention paid 

to aesthetics in design. U.S. tax depreciation schedules (which allow depreciation over a 5-year 

period for retail fixtures, including walk-in refrigerators and freezers)ii may be one driver for 

regular replacement of walk-in refrigeration equipment in the United States. 

Table 3.2.6 Lifetime of Refrigeration Equipment 

Lifetime (in years) Reference 

7-15 Mark Ellis & Associatesiii, New Zealand Minimum Energy Performance 

Standards for Commercial Refrigeration Cabinets 

15 Foster-Miller (2001)iv 

15-20 EPA (2001)v 

15 Arthur D. Little (ADL) (2002)vi 

7-10 Intergovernmental Panel on Climate Change (IPCC) 2001vii 

Some literature reviewed suggested longer lifetimes of up to 20 years or more for walk-in 

refrigeration equipment. Many of the studies cited here related to examination of environmental 

impacts of refrigerant emissions and therefore may not always clearly distinguish between the 

lifetime of the case and the lifetime of the compressor racks.viii However, consultation with 

experts in the field suggested that smaller, independently owned grocery stores were more likely 

to keep equipment longer than larger chain stores. 

3.2.6.2 Envelope 

Unlike motorized or electrical equipment, a walk-in envelope may not have a clear point 

of failure. In some instances, panel and/or door failure may be obvious, such as in the cases of a 

severe puncture or freeze-thaw distortion of panel shape. However, it is more common that box 

components fail from an insulation perspective long before they exhibit any visual forms or signs 

of failure. Even if the envelope box appears structurally intact, its ability to insulate effectively 

may have been diminished substantially by diffusion, water absorption, or wear and tear. 

Owing to this visual ambiguity, and the wide variety of material properties and 

environmental conditions that may impact the envelope, walk-in lifetimes may have a wide 

range. Envelope lifetimes across a variety of sources cited a range of 12-25 years that was first 

referenced in the widely referenced commercial refrigeration equipment industry report by 

Arthur D. Little, Inc. (1996). Anecdotal evidence suggests that some walk-in envelopes remain 

operational for years longer. 

In addition, since there is possibly a large discrepancy between when the envelope fails 

and when the envelope is replaced, all following analysis for the envelope is based on estimated 

replacement rates. 

3.2.6.3 Used or Refurbished Equipment 

Several industry experts suggested there is a significant used/refurbished equipment 

market. However, the size of the used market relative to the new market was not determined. 

3-9 
 

 

 

Those consulted generally agreed that the salvage value of used equipment was very low 

compared to the initial purchase price. This is due to both cosmetic concerns and the custom 

nature of much of the equipment. Additionally, the difficulty in collecting used equipment of the 

same “look” for planned display case line-ups was cited as another reason for the low price of 

used equipment. A survey in the Pacific Northwest reported that for small, independent grocery 

stores (<20,000 square feet) and for independently owned convenience stores, the fraction of 

owners who would consider purchase of refurbished equipment was 25 and 16 percent, 

respectively. For larger, regional chains, this fraction was approximately 11 percent. None of the 

large grocery chains surveyed had plans to purchase refurbished equipment. 

3.2.7 Shipments 

Table 3.2.7 shows the forward-looking trend in values of walk-in coolers and freezers 

shipments beginning in 1993, as estimated by the Freedonia Group in a 2008 report. 

Table 3.2.7 Value of Shipments of Walk-In Coolers and Freezers (in millions) 

Years 1993 1998 2003 2008 2013 

Walk-In Cooler/Freezer Shipments $390 $680 $620 $800 $1,000 

Source: The Freedonia Group, Inc. (2008) 

The walk-in industry lacks aggregated data on actual shipments of walk-ins. Table 3.2.8 

summarizes DOE estimates of historical shipments of envelope and refrigeration equipment. 

Table 3.2.8 Estimated Shipments of Envelope & Refrigeration Equipment, 1998-2009 

Year 

Envelope Refrigeration 

Coolers Freezers Total Multiplex Dedicated Total 

1998 74,481 29,220 103,701 243,114 43,472 286,586 

1999 74,379 29,262 103,641 243,409 43,599 287,007 

2000 74,277 29,304 103,582 243,704 43,725 287,429 

2001 74,175 29,347 103,522 243,998 43,851 287,850 

2002 74,074 29,389 103,462 266,935 22,339 289,274 

2003 73,149 29,035 102,185 266,219 22,033 288,252 

2004 73,104 29,059 102,162 266,382 22,103 288,485 

2005 73,058 29,082 102,140 266,545 22,173 288,718 

2006 73,012 29,105 102,118 266,708 22,242 288,950 

2007 72,967 29,129 102,095 266,217 21,963 288,180 

2008 72,582 28,964 101,546 266,147 21,579 287,726 

2009 72,335 28,858 101,193 265,873 21,557 287,430 

3.2.8 Barriers to Efficiency Improvements 

As the primary barrier to widespread deployment of energy efficient technologies, first 

cost is reflected across the walk-in market in several different ways. 

The structure of the walk-in market is largely responsible for the emphasis on first cost. 

3-10 
 

 

 

The highly competitive market consists of many suppliers, none of whom has a dominant market 

position, meaning that first cost is a primary basis of differentiation between competitors. 

Purchasing decisions may not take lifecycle cost or payback considerations into account because 

in many cases, a general contractor oversees the purchasing of parts and their assembly, which 

incentivizes the selection of lowest cost equipment in terms of capital expense. The multitude of 

supply chain options confounds these issues and the lack of coordination between manufacturers 

of the envelope and refrigeration means that efficient technologies may get overlooked. Cash 

flow can further sway a decision away from energy efficient technologies that may have a higher 

first cost. For example, the uncertain long-term prospects for new restaurants, a major end-user 

of walk-in technologies, often leads to the selection of lowest-cost equipment. 

Assessing lifecycle costs associated with walk-in equipment options can be very 

challenging for end-users. In particular, refrigeration systems and commercial electric rate 

structures are highly complex and variable. Electric rate structures differ across utilities and 

states, making lifecycle cost calculations a challenge even for chains planning to implement 

standard design specifications. These factors create a difficult environment for energy efficient 

technologies; operating savings related to lifecycle costs are often the only way to differentiate 

for customers if the more efficient technology has a higher first cost than its conventional 

counterparts. 

The market structure hinders increased use of energy saving technologies for walk-ins. 

Several of the technologies discussed represent additional complexity for the refrigeration 

system and its control. Training would be required for most refrigeration service technicians 

providing service for walk-in systems. 

3.2.9 Regulatory and Non-Regulatory Initiatives 

The prescriptive standards for WICF set out in EPCA and any standards established by 

DOE during the WICF rulemaking process preempt state standards established for the same 

equipment. Exceptions include any state standards established for equipment not regulated by the 

federal government and state standards that supersede those established by the federal 

government. The following sections detail existing state standards for WICF thatmeet or go 

beyond the EPCA requirements. 

3.2.9.1 California Energy Commission 

The California Energy Commission’s tiered specification regulates the minimum energy 

performance of equipment sold in California. As of January 6, 2006, walk-in coolers and 

freezers have been regulated by the California Appliance Efficiency Regulations. The most 

recent version, published in August 2009 lists the latest requirements for walk-ins sold in 

California after January 1, 2009, which are identical to the standards established at the federal 

level by EPCA for all WICF for which federal standards have been established. 

Additionally, California has established standards for freezers with volumes exceeding 30ft3

, 

wine chillers that are consumer products, commercial refrigerators including but not limited to 

refrigerated bottled or canned beverage machines, commercial refrigerator-freezers, commercial 

3-11 
 

 

 

 

freezers, commercial ice-markets, and water dispensers. These standards are described in Table 

3.2.9. 

Table 3.2.9 Requirements for Walk-ins Sold in California 

Motor Type Required Components 

All Automatic door closers that firmly close all reach-in doors 

All Automatic door closers on all doors no wider than four foot or higher than seven foot, that 

firmly close walk-in doors that have been closed to within one inch of full closure 

All Envelope insulation >R-28 for refrigerators 

All Envelope insulation >R-36 for freezers 

Condenser Fan (i) Electronically commutated motors 

Motors < 1 HP (ii) Permanent split capacitor-type motors, 

(iii) Polyphase motors >1/2 HP, or 

(iv) Motors of equivalent efficiency as determined by the Executive Director 

Single-phase 

Evaporator Fan 

Motors < 1 HP and 

< 460 volts 

(i) Electronically commutated motors 

(ii) Permanent split capacitor-type motors, 

Single-phase 

Evaporator Fan 

Motors < 1 HP and 

< 460 volts 

(i) Electronically commutated motors or 

(ii) Permanent split capacitor-type motors 

Walk-ins Coolers 

and Walk-in 

Freezers with 

transparent reachin doors 

(i) Triple-pane glass with heat-reflective treated glass or gas fill, 

(ii) If appliance has anti-sweat heater without anti-sweat heat controls, then: the 

appliance must have a total door rail, glass, and frame heater power draw of no more 

than 40 W (freezers) or 17 watts (refrigerators) per foot of door frame width; and 

(iii) If appliance has anti-sweat heater with anti-sweat controls, and the total door rail, 

glass, and frame heater power draw is no more than 40W (freezers) or 17W 

(refrigerators) per foot of door frame width, then: the anti-sweat controls shall reduce 

the energy use of the anti-sweat heater in an amount corresponding to the relative 

humidity in the air outside the door or to the condensation on the inner glass pane. 

3.2.9.2 Other U.S. States 

Connecticut, Maryland and Oregon have recently set up energy efficiency standards for 

walk-ins. Connecticut and Oregon’s standards were implemented in 2008 while Maryland’s was 

introduced in 2009. It is unlikely that these standards will have much impact given that they will 

be quickly preempted by the design requirements in EPCA. However, the legislation may 

prepare any manufacturers or consumers in these states for compliance with the federal 

standards. 

3.2.9.3 Australia & New Zealand 

The National Appliance and Equipment Energy Efficiency Committee (NAEEEC) 

establishes minimum energy performance standards (MEPS) for a variety of technologies 

manufactured and sold in Australia and New Zealand. Its standards are based on the North 

American work of the Canadian Standards Association, the California Energy Commission, and 

the U.S. ENERGY STAR program. 

3-12 
 

MEPS for remote and self-contained commercial refrigeration are defined in AS1731.14, 

which targets refrigerated display cabinets used in retail applicationsix. These standards 

specifically omit walk-ins. 

3.2.9.4 Japan 

Japan’s Top Runner program targets energy efficiency standards for a wide range of 

appliances. Although Top Runner sets standards for commercial refrigerators and freezers, units 

produced for industrial use are not included. 

3.2.10 Market Performance Data 

Natural Resources Canada (NRCan) provides estimates of the installed number, sales and 

energy consumption of WICF equipment on an annual basis, summarized in Table 3.2.10. 

Table 3.2.10 Summary of Walk-in Cooler and Freezer Data Compiled by NRCanx 

Equipment 

Type Total Installed Annual Sales 

(New or replacement) 

Annual Energy 

Consumption (kWh) 

Refrigerator (15 m2) - - 16,200 

Freezer (15 m2) - - 21,400 

Refrigerator-Freezer 

(31 m2) - - 30,200 

Total 96,000 3,300 -

DOE was unable to find a source that compiled WICF data in the U.S. Therefore, DOE 

gathered its own industry data by sampling equipment of each class for both envelopes and 

refrigeration systems. The results are shown in sections 3.2.10.1 and 3.2.10.2 

3.2.10.1 Envelope 

In DOE’s research, it was unable to find equipment energy ratings for each equipment 

class or analysis point. This is likely due to the fact that the industry does not yet have a uniform 

method for rating products, but this will likely change with the publication of the WICF test 

procedure NOPR and Final Rule. In the absence of product data, DOE made estimates of 

envelope energy performance using the envelope engineering analysis (described in Chapter 5 of 

the preliminary TSD) with various product sizes. Figure 3.2.1 through Figure 3.2.4 show the 

resulting calculations for each of the four product classes described in Table 3.2.5. The data are 

plotted on a log scale to facilitate comparison between sizes. Without this scale, the energy 

performance range within each product class would make the ranges for smaller sized analysis 

points unreadable. 

3-13 
           

           

1

10

100

180‐900

(24‐200)

795‐2400

(200‐600)

2400‐12500

(600‐3000)

CDEC [kWh/day]

Walk‐inTotal Surface Area (Total Footprint)[ft2]

Low High

Figure 3.2.1 Market Performance Data for the ND.C Equipment Class 

10

100

1000

180‐900

(24‐200)

795‐2400

(200‐600)

2400‐12500

(600‐3000)

CDEC [kWh/day]

Walk‐inTotal Surface Area (Total Footprint)[ft2]

Low High

Figure 3.2.2 Market Performance Data for the ND.F Equipment Class 

3-14 
           

           

10

100

1000

280‐543

(48‐120)

590‐1792

(120‐320)

1370‐11100

(320‐3000)

CDEC [kWh/day]

Walk‐in Total Surface Area (Total Footprint) [ft2]

Low High

Figure 3.2.3 Market Performance Data for the D.C Equipment Class 

10

100

1000

10000

280‐543

(48‐120)

590‐1792

(120‐320)

1370‐11100

(320‐3000)

CDEC [kWh/day]

Walk‐in Total Surface Area (Total Footprint) [ft2]

Low High

Figure 3.2.4 Market Performance Data for the D.F Equipment Class 

3.2.10.2 Refrigeration 

As of now, DOE is not aware of any published market performance data for WICF 

refrigeration. Because there has not been a test procedure in place in this industry, there is no 

established industry-wide metric for performance of equipment as it relates to energy 

3-15 
 

consumption. However, this may change with the recent publication of AHRI 1250. 

Manufacturers’ specification sheets typically provide only information relevant to the end user or 

contractor: refrigeration capacity, dimensions, electrical characteristics, etc. 

In order to gather energy consumption data for refrigeration systems, DOE examined 

manufacturers’ specification sheets and estimated the energy consumption of the system by 

entering the information into DOE’s engineering spreadsheet. The engineering spreadsheet uses 

the calculation methodology contained in AHRI 1250 to calculate energy consumption of the 

system. DOE examined 10 systems in each class that encompass a range of efficiencies that are 

currently on the market. Figure 3.2.5 through Figure 3.2.10 show graphs of the results. 

0

5

10

15

20

25

0.0 10.0 20.0 30.0 40.0

Calculated Energy Consumption 

(MWh/year) 

System Net Capacity (kBtu/h) 

Figure 3.2.5 Market Performance Data for the DC.M.I Equipment Class 

3-16 
0

5

10

15

20

25

0.0 5.0 10.0 15.0 20.0

Calculated Energy Consumption

(MWh/year) 

System Net Capacity (kBtu/h) 

Figure 3.2.6 Market Performance Data for the DC.L.I Equipment Class 

0

5

10

15

20

25

30

0.0 20.0 40.0 60.0 80.0

Calculated Energy Consumption

(MWh/year) 

System Net Capacity (kBtu/h) 

Figure 3.2.7 Market Performance Data for the DC.M.O Equipment Class 

3-17 
0

2

4

6

8

10

12

14

16

18

20

0.0 10.0 20.0 30.0 40.0 50.0

Calculated Energy Consumption 

(MWh/year) 

System Net Capacity (kBtu/h) 

Figure 3.2.8 Market Performance Data for the DC.L.O Equipment Class 

0

5

10

15

20

25

30

0.0 10.0 20.0 30.0 40.0 50.0

Calculated Energy Consumption 

(MWh/year) 

System Net Capacity (kBtu/h) 

Figure 3.2.9 Market Performance Data for the MC.M Equipment Class 

3-18 
0

5

10

15

20

25

30

0.0 10.0 20.0 30.0

Calculated Energy Consumption 

(MWh/year) 

System Net Capacity (kBtu/h) 

Figure 3.2.10 Market Performance Data for the MC.L Equipment Class 

3.3 TECHNOLOGY ASSESSMENT
 

The function of the technology assessment is to develop a preliminary list of technologies 

that could potentially be used to reduce the energy consumption of walk-in coolers and freezers, 

as well as to highlight the developments within those technology categories and their 

applicability to these product classes. Walk-in coolers and freezers present a wide variety of 

design options which could lead to energy savings if implemented in production models. The 

diversity of these options is compounded by the large number of components and corresponding 

energy loss pathways present in this equipment. 

Each unit can be broken down into two components: the envelope and the mechanical 

refrigeration system. Each of these presents specific energy-loss issues which can be addressed 

through new technologies. Within the refrigeration system, most energy loss and waste are due to 

inefficiencies in the components, including the compressor, motors, and fan blades. Advanced 

designs can lead to both direct energy savings, as well as reduction of waste heat discharged into 

the refrigerated space which must be removed. The envelope presents another group of energy 

loss pathways altogether, including the conduction of external heat through insulated walls, as 

well as infiltration of outside air into the refrigerated space and electricity consuming devices 

such as lights and anti-sweat heaters. 

Certain types of walk-in coolers and freezers may also exhibit further means through which 

energy loss occurs. For example, units with the case located outdoors are exposed to increased 

fluctuations in temperature and increased heat load on the surface of the unit due to sunlight, and 

display units exhibit pronounced energy losses due to conduction through and opening of the 

glass doors, as well as the presence of anti-sweat heating devices. The following assessment 

3-19 
 

 

 

provides descriptions of technologies and designs that apply to all equipment classes for 

envelope and refrigeration, designs that apply only to particular classes for envelope and 

refrigeration. 

3.3.1 Technologies and Designs Relevant to All Envelope Equipment Classes 

3.3.1.1 Wall, Ceiling, and Floor Insulation 

Most walk-in cooler and freezer envelopes are constructed from panels known as 

Structurally Insulated Panels (SIPs), which are comprised of a sandwich of metal skins 

encapsulating an insulating material. Most walk-ins currently manufactured and installed use 

traditional foam materials as insulation. Their main purpose is to reduce heat transfer from the 

external environment to the internal conditioned space of the walk-in. 

Improvements to the insulating capacity of the envelope could be achieved through a 

number of methods. The most basic of these would be increased insulation thickness using 

existing foam insulating materials. Another option would be the incorporation of insulating 

materials that have higher thermal resistance per inch thickness. One such technology is the 

Vacuum Insulated Panel (VIP), which consists of an outer air-tight membrane surrounding a core 

material. The inner core is evacuated to remove air from the material. This greatly reduces heat 

conduction on a per inch basis compared to foam materials. Other options include the 

incorporation of aerogels, a low-density and low heat conducting material. 

3.3.1.2 Door Gaskets 

All walk-in doors utilize seals to prevent air exchange with the surroundings when the 

door is closed. These seals typically consist of rubber gaskets which are compressed when the 

door latch is closed, or magnetic, vinyl-coated systems used display glass doors. Improvements 

in these systems and the seal materials could result in greater insulating capacity as well as less 

air leakage, reducing energy loss due to both conduction and air infiltration. 

3.3.1.3 Panel Interface Systems 

Panel interface systems include the methods and materials designed to seal the panel-topanel, panel-to-floor, and other interfaces present. Use of improved materials, geometries, and 

manufacturing techniques could serve to further reduce infiltration and conductive losses and 

improve the overall insulating capacity of the envelope, meaning that less energy input would be 

required by the refrigeration system. 

3.3.1.4 Electronic Lighting Ballasts and High-Efficiency Lighting 

Many fluorescent lighting systems currently in use to illuminate the interior of walk-ins 

employ traditional magnetic ballasts. These ballasts generate significant amounts of heat due to 

resistive losses incurred in the circuit. This results in increased energy consumption to power the 

lights, as well as an increase in the cooling load to remove the waste heat generated by the 

ballasts. Solid state electronic ballasts serve to reduce this waste heat, as the integrated circuits 

3-20 
 

 

employed produce very low resistive losses. These advanced ballasts also lead to more efficient 

operation of the fluorescent lamps, thereby reducing the electricity consumption of the lights. 

Moving the ballasts away from the lamps entirely, to a location outside of the refrigerated space, 

is another option. This would ensure than any waste heat produced would be discharged to the 

surroundings, rather than to the refrigerated space, where it would have to be removed by the 

cooling system. 

In addition to fixtures and ballasts, new advanced lights such as light emitting diodes 

(LEDs) and organic light emitting diodes (OLEDs) offer significant increase in efficacy. 

Compared to standard fluorescent systems, the electricity consumption and waste heat generated 

are far lower. Nearly every major display door manufacturer offers LED lighting as design 

option. LED bulbs that fit in Edison type fixtures are also widely available. 

3.3.1.5 Occupancy Sensors 

One major source of energy consumption in a walk-in is the operation of lighting when it 

is not needed, primarily due to lights being left on when the unit is unoccupied. Occupancy 

sensors ensure operation of the interior lighting when an individual is present and working inside 

the refrigerated space or viewing products in a display type walk-in. When motion has not been 

detected for a set period of time, the lights are turned off. This would reduce waste due to lights 

being left on unnecessarily. Moreover, the sensors could also be used to notify personnel of 

periods when the door is ajar; that is, if the door is open and there has been no one present inside 

the space for a period of time. This would save energy due to loss of refrigerated air from the 

interior space. 

3.3.1.6 Automatic Door Opening and Closing Systems 

Doors left open accidentally by employees can be a major cause of losses from the 

envelope. To avoid accidental and intentional door opening frequency and duration, especially 

while products are being loaded into the walk-in, the use of automatic door opening and closing 

mechanisms can reduce air infiltration. By sensing approaching personnel and through the use of 

powered door openers, the door can be quickly opened and closed at a rate that both ensures safe 

movement through the doorway and minimizes the duration of the door opening event. Instead of 

door propping while loading, the door would only be opened for the short period that a person or 

forklift needs to pass through the doorway. 

3.3.1.7 Non-Penetrative Internal Racks and Shelving 

Many manufacturers have noted that end users and customers will install interior shelving 

units and racks in the walk-ins using penetrative fasteners such as nails and screws. These 

compromise the inner skin and insulation of the envelope, resulting in reduced insulating 

capacity and possibly air leakage. The use of freestanding racks and shelving units by end users 

could be a simple and effective method for reducing losses. 

3.3.1.8 Air Curtains 

3-21 
 

 

 

Air curtains consist of fans mounted horizontally or vertically that direct a stream of air 

across a door opening. When the door is opened, the air current is activated, blowing air 

perpendicular to direction of air movement into and out of the walk-in. This air barrier greatly 

reduces unwanted exchange of air while offering unobstructed visual or movement barrier. 

Two types of air curtains exist: recirculating and non-recirculating. Non-recirculating 

units are the most common, as these simply use air from the interior space to form the moving 

stream. The air then impinges upon the floor and the stream splits. If properly positioned, the 

systems are very effective at reducing air infiltration. In recirculating units, the stream of air 

captured through a floor grate and run through the blower again. Manufacturers claim that 

recirculating units these systems are even more effective than non- recirculating. Air curtains are 

not standard on most walk-ins, but have been widely available for quite some time and are often 

installed by end users as an accessory. 

3.3.1.9 Strip Curtains 

Strip curtains are barriers composed of vertically-oriented strips of plastic, usually clear 

PVC, which can be suspended in the doorway opening of a walk-in. When undisturbed, the 

curtain forms a barrier which limits movement of the cooled air out into the environment, yet 

allows for easy and unobstructed passage through the doorway. These are commonly installed by 

end users for the intent of saving energy. Generally, strip curtains are used in larger units which 

experience heavy traffic, such as constant movement of goods using forklifts. However, their 

proficiency in preventing the loss of chilled air from the inside of the refrigerated space makes 

them a candidate for use in walk-ins of all sizes and uses. 

3.3.1.10 Refrigeration System Override 

During periods of high traffic, such as when a shipment of product is received and must 

be transferred into the walk-in, the door to the cooler or freezer may be repeatedly opened or 

simply left open for a long period of time. With traditional systems, the thermostat engages the 

compressor and fans during such periods. However, such operation wastes a large amount of 

electricity, as the attempt on behalf of the system to cool the interior space is lost via the open 

door. A better alternative is to simply override the thermostat, turning off the refrigeration 

system completely during high-traffic periods and reengaging it after the tasks have been 

performed. Such a simple control would prevent the cooling system from continuously running 

at maximum capacity in an attempt to bring the inside temperature down to the desired value 

while continuously ejecting cold air to the surrounding environment. The result would be an 

immediate and sizeable energy savings. 

3.3.1.11 Air and Water Infiltration Sensors 

Infiltration of water and/or water vapor into the envelope insulating material may lead to 

significant reductions in the insulating capacity of the affected regions due to the thermal 

conductivity properties of water. This sort of infiltration may result from specific incidents, such 

as punctures or damage or a steady-state process occurring over a long period of time. A water 

condensate or vapor sensor, implanted within the insulating material would allow for early 

detection of damage to the insulating material. This would prevent continued operation with a 

3-22 
 

damaged unit and would provide notification of the need for repairs. As a result, the energy 

wasted during sustained operation of a damaged unit would be conserved. In addition, pressure 

or flow sensors may be utilized to directly measure walk-in air exchange rates, providing endusers data to use historical air exchange patterns to monitor real-time performance. 

3.3.1.12 Humidity Sensors 

Humidity of the air is another factor which can influence the performance of the 

mechanical refrigeration system. As air with a higher humidity has a higher specific heat, it thus 

requires more energy to cool the air on a day with high humidity. Sensors installed in the system 

could provide real-time information regarding the outside humidity, which would allow for more 

informed decisions to be made regarding topics such as the loading and loading of product at 

certain times. Such intelligently managed use would result in lower infiltration losses due to 

prolonged door opening on days exhibiting adverse operating conditions. 

3.3.1.13 Heat Flux Sensors 

As mentioned earlier, damage to the envelope of the walk-in can occur due to many 

reasons, including penetrative fasteners used to attach shelves or racks and/or long-term 

degradation of insulation due to gas diffusion or water infiltration. Heat flux sensors are 

available which use a simple hot plate method to provide real-time information regarding the 

insulating properties of a wall on which they are mounted. This non-destructive R-value 

monitoring would provide manufacturers with useful data of walk-in performance as installed in 

the field and allow end-users to monitor performance of the insulation over time to avoid energy 

losses incurred due to drop in insulation R-value. 

3.3.1.14 Vestibule Entryways 

The implementation of vestibule or air-lock doors would greatly reduce the losses that 

arise as a result of opening the doors for entry. This type of entry system is typically used in 

larger building entrances to prevent heat loss due to door opening air infiltration. The doors open 

and close sequentially during entry and exit, never allowing direct air exchange. Instead, only a 

small amount of air would move with the user into the small space between the two doors. This 

would significantly reduce the increase in interior temperature that occurs each time the door is 

opened, as well as the corresponding amount of energy required to cool that space back down to 

the desired set point. 

3.3.1.15 Revolving Doors 

Another provision for the reduction of losses from door opening would be the use of 

revolving doors. Like vestibule entries, revolving door systems are commonly used for the 

entryways of large buildings. Similarly, they prevent direct exchange of air and reduce the rate of 

infiltration compared to a standard door. 

3.3.1.16 Fiber Optic Natural Lighting 

3-23 
During day light business hours, instead of using electrically powered lighting systems, 

roof mounted collectors can be used to direct sunlight into fiber optic cables that transmit the 

light to where it is needed in a walk-in cooler resulting in immediate energy savings. Artificial 

lighting, such as in the form of the high-efficiency lighting systems mentioned previously would 

also need to be present, as walk-in coolers and freezers are generally accessed at all hours in 

many applications. 

3.3.1.17 Energy Storage Systems 

Thermal energy storage systems could be utilized to levelize cooling demand on the 

compressor and associated refrigeration system, allow the system to operate only during optimal 

environmental conditions and shift electrical demand to off-peak hours to achieve cost savings. 

For example, the refrigeration equipment could cool a large mass during the night when outdoor 

temperatures are lowest and electricity prices are cheapest. During the daytime or periods of 

peak demand, this stored energy could then be utilized. Storage would allow for systems to be 

designed for steady-state operation rather than being over sized for “worst-case” weather or 

product loading scenarios. Generally, the more time the system operates at 100% capacity 

efficiency increases cost of operation decreases. 

3.3.2 Technologies and Designs Relevant to Display Envelopes Only 

The following technologies are relevant only to walk-in coolers and freezers which also 

feature display fronts: display and window glass system insulation performance, anti-sweat 

heater controls, non-electric anti-sweat systems, no anti-sweat systems, and automatic insulation 

deployment systems. 

3.3.2.1 Display and Window Glass System Insulation Performance 

The glass display door heat transfer losses for represents 30-40% of walk-in energy 

consumption. While current regulation prescribes minimum standards for number of panes, gas 

fill and low emissivity coatings, there is significant opportunity for improvement. In addition, 

windows used in non-display doors also contribute to energy consumption but on a much lower 

percentage basis. 

Improvements to reduce heat transfer performance could include the use of additional 

panes of glass and expanded use of inert gas filled panes using argon, krypton or xenon. The 

treatment of the window glass with advanced low emissivity coatings and increasing the number 

of coated surfaces could also reduce losses due to radiation heat transfer. The result of these 

improvements would include both direct energy savings, through reduced conduction losses, and 

an indirect reduction in energy consumption due to reduced anti-sweat heater demand. 

3.3.2.2 Anti-sweat Heater Controls 

In display units, the glass door external surface may experience temperatures below the 

dew point of the ambient air with which they are constantly in contact. As a result, condensation 

can form in on the surface of the doors, reducing visibility of the product and also possibly 

leading to ice buildup or pools of condensate forming at the base of the glass door. This 

3-24 
 

 

phenomenon is known as “sweating”. To prevent this, anti-sweat heaters are generally employed 

in order to ensure that the external glass temperature is sufficiently high to avoid sweating. 

Generally, electric heater wire, in contact with the door perimeter, is energized to 

continuously heat the glass. However, anti-sweat heat may only be required during particularly 

humid environmental conditions or walk-in temperatures. Control devices are available that 

sense external humidity and temperature regulate anti-sweat heater wire use on demand. These 

systems significantly reduce the required daily electrical demand. 

3.3.2.3 Non-Electric Anti-sweat Systems 

While conventional anti-sweat heaters operate using separately powered electric 

resistance heater wire, any heat source capable of bringing the door surfaces to temperature 

could also serve this purpose. It may be possible, similar to hot-gas defrost, to utilize the waste 

heat generated by the mechanical refrigeration system to provide the required glass door heating. 

In these non-electric systems, a heat transfer fluid could be used to absorb heat from the 

refrigeration system and reject heat to the glass doors. By utilizing waste heat that is readily 

available a major source of electrical energy consumption in display units may be entirely 

eliminated. 

3.3.2.4 No Anti-sweat Systems 

Another option for addressing the issue of sweating is the use of static systems that 

prevent the phenomenon from occurring. These include multi-pane glass doors which have 

greater insulating properties, preventing the exterior temperature from becoming low enough for 

sweating to occur. Another option may be advanced hydrophobic materials that prevent 

condensate from attaching or lingering on the glass surface and therefore prevent the formation 

of water droplets that may obscure a customer’s view of a product. 

3.3.2.5 Automatic Insulation Deployment Systems 

In many businesses, such as convenience and grocery stores with limited hours of 

operation, glass display doors are not utilized during non-business hours. In such applications, 

automatic insulation deployment systems could be put in place to lower a layer of insulation over 

the interior or exterior surface of the glass doors during non-business hours, thus increasing the 

thermal resistance of the door and, correspondingly, the net insulating capacity of the entire 

envelope. This would greatly reduce conduction losses and lead to a direct energy savings. 

3.3.3 Technologies and Designs Relevant to All Refrigeration Equipment Classes 

3.3.3.1 Evaporator and Condenser Fan Blades 

Conventional fans have sheet metal blades mounted to a central hub, and are generally 

not optimized for the specific application in which they will be used. Instead, they are designed 

for mass production and scalability in order to minimize production cost and waste. Optimization 

of fan design for specific applications could significantly reduce input energy needed in order to 

perform the necessary work. Higher efficiency fan blades are capable of moving more air at a 

3-25 
 

given rotational speed when compared to traditional fan blades. This means that a smaller motor 

can be used, or the existing motor can be run at a lower speed, resulting in direct energy savings. 

The improvements described here would be applicable to both evaporator and condenser fans, 

though evaporator fans would likely stand to earn greater efficiency gains due to the fact that 

sheet metal fans are poorly suited to the higher pressure drops encountered in this application. 

3.3.3.2 Improved Evaporator and Condenser Coils 

The effectiveness of the refrigeration system in moving heat from the temperaturecontrolled space to the ambient environment is constrained by the ability of the evaporator and 

condenser coils to transfer heat. Coils are generally constructed of copper and aluminum, with 

these materials being chosen for their favorable heat transfer characteristics. Enhancements to 

both the refrigerant side (inside) and air side (outside) of the coils can improve their heat transfer 

characteristics, requiring less compressor power and fan energy to achieve the same system 

capacity. Improvements to the refrigerant side of the coil can include increased tubing passes as 

well as changes in the geometric profile of the tubing itself. Air-side improvements consist of 

decreasing the spacing between the fins, thus increasing the number of fins per unit coil length, 

as well as changes in the fin patterns. Increased overall coil size also improves heat transfer, but 

this is infeasible in some cases due to space constraints on both the evaporator and condenser 

coils. 

3.3.4	 Technologies and Designs Relevant to Dedicated Condensing Refrigeration 

Systems Only 

3.3.4.1 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. 

3.3.4.2 Higher-Efficiency Fan Motors 

Two separate sets of fan motors service the evaporator and condenser of the unit, 

respectively. Their functions are to facilitate heat transfer by moving air across the heat 

exchangers, in order to move heat out of the refrigerated volume and discharge it to the ambient 

environment. The current regulations dictate that all evaporator fan motors must be either 3­

phase or electrically commutated motors (ECMs), and that all condenser fan motors must be 

ECMs, permanent split capacitor motors (PSCs), or 3-phase. This eliminates the usage of an 

older and less sophisticated motor type, the shaded-pole motor. Aside from motor type alone, 

other design options can be implemented into the motors in order to reduce internal friction and 

improve operating capacity. The result will be that less electrical energy input will be required to 

generate the same amount of output shaft work, and less waste heat will be discharged due to 

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friction, reducing electricity consumption directly and, in the case of the evaporator fan motors, 

reducing the system heat load, thereby reducing the indirect consumption of the system in 

removing that load. 

3.3.4.3 Automatic Evaporator Fan Shut-Off 

Typically, evaporator fans run at all times to circulate cool air in the walk-in. This design 

option consists of a control that would automatically shut off evaporator fans whenever the walkin door is opened. The result would be that less chilled air would be blown out into the walk-in’s 

surroundings, meaning that less energy would be needed to bring the interior space back down to 

temperature following a door opening. 

3.3.4.4 Evaporator Fan Control 

In traditionally operated systems, evaporator fans run at all times, whether or not the 

compressor is running. In many instances, the evaporator fan motors are running for more time 

than is actually necessary, resulting in overuse of electrical power. 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. These could include timers or sensors which detect 

conditions inside the refrigerated space and control the motors accordingly. 

3.3.4.5 Higher-Efficiency Compressors 

The compressor is the component that uses the most power out of all those comprising 

the refrigeration system, making it a likely and appropriate target for improvement. Even a small 

percentage increase in compressor efficiency would result in very large energy savings over the 

life of the product. Currently, several types of compressors are in use for walk-in refrigeration 

systems. Smaller systems utilize hermetic reciprocating piston compressors, while larger units 

utilize semi-hermetic compressors. Additional compressor types exist which have not achieved 

large market share, including scroll compressors, which generally exhibit quite high efficiencies. 

Moreover, multiple capacity compressors present an opportunity for energy savings as well. 

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. 

3.3.5	 Technologies and Designs Relevant to Low Temperature Refrigeration Systems 

Only 

3.3.5.1 Hot Gas Defrost 

As the air in the refrigerated space is cooled, water vapor condenses on the surface of the 

evaporator coil, and, if the coil temperature is below freezing, ice will form, creating a layer over 

the surface of the coil. If this layer grows to be too thick, air flow will be decreased and thermal 

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resistance will increase, resulting in reduced cooling performance. Thus the removal of 

evaporator coil frost is imperative. 

Hot gas defrost involves the recirculation of hot gas discharged from the compressor to 

warm the evaporator. Compared to other defrosting methods, namely electric defrost, energy 

consumption is much less as the heat comes from an existing by-product of the process. 

However, sophisticated controls are required, along with complex pipe routing, in order for the 

system to be effective. A more serious consequence of using this defrosting system is cracking 

and leaking resulting from thermal stresses induced upon the coolant piping due to alternate 

exposure to high and low-temperature refrigerant. 

3.3.5.2 Defrost Controls 

Management of frost buildup on coils is essential in ensuring continued efficient 

operation of the unit. Traditionally, defrosting systems were run on regular intervals utilizing a 

simple timer. However, this system has two possible negative consequences in that the defroster 

may run too often, resulting in wasted energy, or not often enough, resulting in decreased system 

performance. Current systems allow for control of the termination of defrosting based on 

temperature; when the coils reach a specified temperature, the defroster is turned off. However, 

initiation of the cycle still occurs on a periodic basis using a timer. 

Control of the defrost cycle requires the use of sensors in order to determine that a defrost 

cycle is needed. The data collected can consist of either the temperature drop across the coil or 

detection of the physical thickness of frost buildup using photocells. The first of these two 

methods is based on the idea that decreased airflow across the coil is a result of frost buildup, 

meaning that the temperature differential across the coil will increase. However, there are issues 

in that external factors aside from frost buildup on the coil may be the reason for decreased 

airflow. The second method is more accurate but requires more sophisticated sensors. 

3.3.6 Technologies and Designs Relevant to Outdoor Refrigeration Systems Only 

3.3.6.1 Floating Head Pressure 

Traditionally, the pressure at which the compressor discharges, known as the head 

pressure, is kept at a constantly fixed setting in order to enable operation over a variety of 

environmental 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 evaporative condenser against freezing and maintains the necessary pressure difference 

across the expansion valve. 

However, modern technology, in the form of more sophisticated expansion valves, allows 

for the use of floating head pressure schemes, in which the refrigerant flow is dynamically 

controlled over a broad range of external temperatures. In this case, condensing temperatures 

down to 70 degrees Fahrenheit can be utilized, much lower than the temperatures of 90 or 95 

degrees necessary for a fixed-head pressure system. In this case, the evaporative condenser is in 

constant operation, rather than simply turning on and off as needed. This has the potential to 

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generate a significant net energy reduction through a decrease in compressor energy use, and 

also can reduce the wear induced upon moving parts due to continual starting and stopping. 

3.3.6.2 Economizer Cooling 

Economizer cooling consists of directly venting outside air into the interior of the walk-in 

when the outside air is as cold as or colder than the interior of the walk-in. This relieves load on 

the refrigeration system when pull-down load is necessary. 

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REFERENCES 

i It was formerly known simply as the Air-Conditioning and Refrigeration Institute (ARI) until 

January 1, 2008 when its merger with the Gas Appliance Manufacturers Association (GAMA) 

was finalized. 

ii U.S. Internal Revenue Service. Field Directive on the Planning and Examination of Cost 

Segregation Issues in the Retail Industry. 2004. (Last accessed June 25, 2007.) 

<http://www.irs.gov/businesses/article/0,,id=151273,00.html> The June 25, 2007, material from 

this website is available in Docket EE-2006-STD-0126. For more information, contact Brenda 

Edwards-Jones at (202) 586-2945. 

iii Mark Ellis & Associates. New Zealand Minimum Energy Performance Standards for 

Commercial Refrigeration Cabinets, Prepared for the Energy Efficiency and Conservation 

Authority. 2003. (Last accessed June 26, 2007.) <http://www.eeca.govt.nz/eecalibrary/products/standards/report/meps-for-commercial-refridgeration-cabinets-03.pdf> The 

June 26, 2007, material from this website is available in Docket EE-2006-STD-0126. For more 

information, contact Brenda Edwards-Jones at (202) 586-2945. 

iv Foster-Miller. Development and Demonstration of an Advanced Supermarket 

Refrigeration/HVAC System. 2001. Oak Ridge National Laboratory: Oak Ridge, TN. Report 

No. ORL-970163. 

v

 U.S. Environmental Protection Agency Office of Air and Radiation. U.S. High GWP Gas 

Emissions 1990–2010: Inventories, Projections,and opportunities for Reductions, June 2001. 

2001. (Last accessed April 3, 2009.) <http://www.epa.gov/highgwp/projections.html > The June 

26, 2007, material from this website is available in Docket EE-2006-STD-0126. For more 

information, contact Brenda Edwards-Jones at (202) 586-2945. 

vi ADL. Final Report to the Alliance for Responsible Atmospheric Policy, March 21, 2002. 

2002. (Last accessed April 3, 2009.) <http://www.arap.org/adlittle/toc.html> The June 26, 

2007, material from this website is available in Docket EE-2006-STD-0126. For more 

information, contact Brenda Edwards-Jones at (202) 586-2945. 

vii Intergovernmental Panel on Climate Change, World Meteorological Organization/United 

Nations Environment Programme. Good Practice Guidance and Uncertainty Management in 

National Greenhouse Gas Inventories. 2001. (Last accessed June 26, 2007.) <http://www.ipccnggip.iges.or.jp/public/gp/english/3_Industry.pdf > The June 26, 2007, material from this 

website is available in Docket EE-2006-STD-0126. For more information, contact Brenda 

Edwards-Jones at (202) 586-2945. 

viii Sand, J.R., S.K. Fisher and V.D. Baxter. Energy and Global Warming Impacts of HFC 

Refrigerants and Emerging Technologies. 1997. (Last accessed June 25, 2007.) 

<http://www.afeas.org/tewi/tewi-iii.pdf> The June 25, 2007, material from this website is 

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available in Docket EE-2006-STD-0126. For more information, contact Brenda Edwards-Jones 

at (202) 586-2945. 

ix CLASP, Energy Efficiency Standards and Labeling Information Clearinghouse, “AS 1731.14 

Minimum Energy Performance Standards (MEPS) requirement for Refrigerated Display 

Cabinets”, http://www.clasponline.org/clasp.online.worldwide.php?programinfo=1147 

x

 Natural Resources Canada, “Walk-in Commercial Refrigeration”, 

http://oee.nrcan.gc.ca/industrial/equipment/commercial-refrigeration/index.cfm?attr=24 

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