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Self-contained, Commercial Refrigerators and Freezers

Introduction

Self-contained, commercial refrigerators and freezers are electrically powered refrigerated cases with shelves or drawers, having one, two or three opaque or transparent doors, and may have one or more interior lights to illuminate the contents. These appliances consume a considerable amount of energy.

Commercial refrigerators and freezers are used primarily in the retail sector by convenience stores, supermarkets, restaurants, pubs, cafeterias, flower shops, drug stores and others for storing or merchandising refrigerated or frozen products such as cold drinks, ice cube bags, frozen foods, etc.

Canada has over 340,000 commercial refrigerators and freezers. Approximately 38,000 units sell each year. Table 1 shows how much energy each type uses.

On September 1, 2006, ENERGY STAR® qualifying criteria for Commercial solid door, self-contained refrigerators and freezers came into effect in Canada. ENEGY STAR qualified products are more energy-efficient and use considerably less energy. Note: The ENERGY STAR criteria only covers solid door refrigerators and freezers, whereas the CSA standard covers both solid-door and glass-door equipment. The minimum performance levels specified by ENERGY STAR are generally lower (more energy-efficient) than those set out in the CSA standard.

Table 1: Estimated Canadian Market and Estimated Annual Energy Consumption (2003) for Self-contained, Commercial Refrigerated Appliances
Appliance Type Approximate Number of Units in Use in Canada ( 2003 ) ( Units ) Estimated Total Annual Consumption in Canada ( kWh/year ) Estimated Annual Sales ( Units/year )
Solid door refrigerators 152,000 577,600,000 17,000
Solid door freezers 94,000 705,000,000 10,000
Beverage merchandisers 94,000 557,420,000 11,000
Totals 340,000 1,840,020,000 38,000

The most common types of commercial refrigerators and freezers and their average annual consumption are listed on Table 2.

Table 2: Approximate Annual Energy Consumption of Various Types of Self-contained Commercial Refrigerators and Freezers in Use in Canada
Appliance Type and Configuration Average Unit Energy Consumption ( kWh/year ) Annual Operating Cost* ( $ )
Solid door refrigerators
One-door 2,300 $ 230
Two-door 4,300 $ 430
Three-door (or more) 6,300 $ 630
Solid-door freezers
One-door 5,200 $ 520
Two-door 9,800 $ 980
Three-door (or more) 14,400 $ 1440
Beverage merchandisers
One-door
Two-door
Three-door (or more)
* assuming electricity cost of $0.10 /kWh

Tables 1 and 2 do not include certain special models of self-contained, commercial refrigerators and freezers. The roll-in model has a bottom leveled with the outside floor, permitting wheeled carts to roll in. The pass-through model has doors on opposite sides. The roll-through model is a combination of the roll-in and pass-through models. The under-counter preparation tables display sandwiches, pizza and other foods and the refrigerated buffet tables. Approximately 32 per cent of commercial refrigerated cabinets are special models like these.

The design of refrigerated open display cabinets differ totally from the design of commercial refrigerated and freezers with doors. The open refrigerated display cabinets consume a lot more energy than appliances with doors because the free air movement that takes place between the room and the refrigerated space allows the exchange of cold air and room air, increasing significantly the cooling load and the rate of build-up of frost on the cooling coils. Refrigeration for these cabinets is usually supplied by an individual remote refrigeration system for each appliance or by a large central system. Frost on the cooling coils of these units must also be removed frequently to maintain cooling performance; defrosting uses energy, and in certain types (like manual defrost,) add a great deal of inconvenience. Closed, refrigerated cabinets need much less energy and less defrosting than open cabinets. The closed cabinets are usually self-contained, and except for the larger units, can usually be supplied from 15 Ampere, 120 V wall electrical outlets.


Minimum Efficiency Standards and Regulations

Minimum performance criteria for annual energy consumption for commercial refrigerators and freezers are specified in the Canadian Standards Association standard CAN/CSA-C827-98 (R2003): Energy Performance Standard for Food Service Refrigerators and Freezers. The maximum daily levels vary depending on the volume of the refrigerator or freezer. Ontario and New Brunswick specify this standard in the energy efficiency regulations for self-contained commercial refrigeration units.

On March 1, 2003 the California Energy Commission (CEC) introduced regulations with minimum energy performance levels (Tier 1 level) to cover commercial refrigerated appliances and updated the levels on August 1, 2004 (Tier 2 level). The consumption levels selected were intended to exclude the highest consuming appliances in each class (25 per cent of the number of models in the California market in 2001 for Tier 1 and 50 per cent of the models in the market in 2001 for Tier 2). Another update was introduced on January 1, 2006 and a further update is scheduled to become effective on January 1, 2007. The California regulations are available on the Web.

Replacing all commercial refrigerators and freezers in Canada with Tier-2-level would save 279 GWh a year. This includes cross-effects with space heating and cooling systems. This would reduce Canada's CO2 emissions by 54 million kg per year. These refrigerators and freezers last about 10 to 11 years. So as more efficient units replace old ones, Canada could reduce these emissions gradually.

In January 2006 Natural Resources Canada (NRCan) announced regulation for the minimum efficiency of self-contained commercial refrigerators, freezers and combination refrigerator-freezers with opaque or transparent doors. Starting April 1, 2007 the Canadian levels will be similar to the California Tier 1 and Tier 2 levels. These levels will also harmonize with planned US Federal government regulations. You can find out about these regulations on the web site Amendment to Canada's Energy Efficiency Regulations.

The Regulation applies to products manufactured or imported after April 1, 2007, many of the models sold now already meet or surpass the level. On January 1, 2008 a higher efficiency level will go into effect.

In addition to the appliances covered by the proposed regulation, manufacturers will have to report energy used by self-contained no-door refrigerators and freezers, but they will not have to meet an efficiency level.

ENERGY STAR® Qualified Commercial Refrigeration Products

On September 1, 2006, the ENERGY STAR qualifying criteria for commercial solid door refrigerators and freezers (Version 1.0) went into effect in Canada.

The ENERGY STAR program will draw its lists of qualified models in Canada from third party verified model information, as required by regulation. The ENERGY STAR symbol may be affixed to the qualified commercial solid door refrigerators and freezers.

List of models: Commercial solid door refrigerators and freezers

This link will take you to a product list on the US ENERGY STAR Web site. Canada is sharing lists of ENERGY STAR qualified commercial solid door refrigerators and freezers with ENERGY STAR in the United States. Many of the products listed are available in Canada. A Canadian list of models will follow based on ENERGY STAR reporting to Natural Resources Canada.

Technical specifications for solid door refrigerators and freezers for manufacturers.

The minimum performance levels for ENERGY STAR are more energy-efficient than those in the CSA standard.

Energy Efficient Improvements

Most features making residential refrigerators and freezers much more efficient over the past 20 years now come in commercial refrigerators and freezers. For many years, Canada has regulated the minimum energy efficiency of domestic refrigerators and freezers. Electricity costs continually rise and regulators are stipulating levels of energy efficiency, making it economic to use these features. Some of these innovations now come in certain models of commercial refrigerators and freezers. Here are features that will save energy in commercial refrigerators and freezers:

  1. Energy-efficient lighting – Much more energy efficient than incandescent lamps, fluorescent lighting with magnetic ballasts now comes in transparent door cabinets. You can buy even more efficient lighting for glass-door cabinets: T8 fluorescent lights with electronic ballasts, compact fluorescent lamps, LED lights, and programmable timers and controls cycling lights and temperature as needed.

  2. More energy-efficient compressors – Commercial refrigerators and freezers use reciprocating compressors, modified to use more ecologically friendly refrigerants. Energy-efficient features for refrigerator compressors, such as scroll compressors and linear compressors, are just beginning to appear in few new commercial refrigerators and freezers.

  3. High efficiency small motors – To drive fans, some manufacturers have started to use much more efficient motors. Permanent magnet, electronically-commutated motors (ECM) with efficient fan blades run cooler. Refrigerators and freezers must remove motor and fan-blade heat. So more efficient fans mean using less energy for the compressor.

  4. Cabinet design improvements – Several improvements appear in new models:
    • Better face frame and door gasket design needing less anti-sweat heat. Anti-sweat heaters stop surface condensation around the door.
    • Thicker wall insulation – move from 1.5 inch thickness to 2 or 2.5 inch thickness.
    • Foamed-in-place insulation rather than mineral fiber insulation.
    • Better insulation for glass doors, including double or triple glazing and low-E glass.
    • Superior glass door designs.
    • Better condensates drain design, including a trap to prevent air infiltration and reduce energy consumption.

  5. Improved defrost methods – Here are some new methods reducing the energy required to melt the ice build-up on the cooling coils and to dispose the condensate including:
    • Off-cycle defrost – turns off refrigerant flowing to the coil, while leaving the evaporator fan running. This is used when air temperatures two or more degrees above freezing. The case air warms, then melts, the frost. Usually a temperature sensor controls defrosting.
    • Electric resistance heating defrost – where the air temperature is not high enough to defrost the coil (e.g., in freezers), and where defrost must occur quickly to stop case or product temperature from rising.
    • Hot-gas defrost – uses hot compressor gas to warm the evaporator from the inside. This is used for many air temperatures because it is more efficient than electric-resistance defrost. But hot-gas defrost needs more complicated and costly valves, piping and controls than electric defrost So self-contained commercial refrigerators and freezers do not yet use hot-gas defrost.
    • Improved defrost control – timers used to turn defrost on, then off. When enough time passed for a large frost-layer to form, defrosting began. Defrosting lasted long enough for the worst frost-layers to melt. These formed when people continually opened the case door on humid, summer days. Now temperature ends defrosting. In either off-cycle or electric defrost, when the coil warms enough, showing it has completely defrosted, the control shuts off the defrosting.
    • Disposal of condensate – in most commercial refrigerators and freezers, defrost condensate is collected in a tray in the bottom of the unit exterior, heated and evaporated to eliminate the requirement for connecting the unit to a drain. Some units use electric heaters (up to 500 watts) to achieve this evaporation. Hot gas from the compressor, which would be normally rejected to the atmosphere, can be used for this evaporation and thus eliminate electrical energy consumption for evaporation of the condensate.

  6. Surface condensation control, using compression heat of the refrigerant gas rather than electric resistance heaters installed under the surface of the door opening.
    • In residential refrigerators, on the surface of the cabinet around the door seal, "anti-sweat" heating stops condensation. Instead of an electric heater doing this, hot compressor gas does. In fact, residential refrigerators and freezers use little electric heating against door seal condensation. But most commercial refrigerators and freezers do. To save energy in these models, some manufacturers now use hot gas anti-sweat heaters.