Walk-in refrigeration

Walk-in refrigeration and energy efficiency

Walk-in refrigerators and freezers are very large, insulated, enclosed spaces used to store and/or display refrigerated or frozen food or other perishable goods. They are used primarily in the food service and food sales industry.

(Commercial refrigerators and freezers used in supermarkets and food processing and packaging can be much larger and are typically supplied by central refrigeration systems.)

Walk-in refrigerators operate above 0°C and at or below 13°C, and walk-in freezers operate at or below 0°C.

They are not regulated under Canada’s Energy Efficiency Regulations and there is no ENERGY STAR® certification for high efficiency available.

There are, however, energy-efficient components available to make up more energy-efficient walk-in refrigerators or freezers.

How a typical system works

A typical walk-in refrigerator or freezer system is shown in the diagram below. The room is cooled by a packed unitary or split refrigeration system consisting of:

  • an evaporator fan coil (usually mounted on the room’s ceiling)
  • a compressor (usually mounted outside the room)
  • a water- or air-cooled condensing coil

Refrigerant continuously circulates from the compressor to the condenser, into the expansion device, through the evaporator and back to the compressor.

The refrigerant absorbs heat from the room and expels that heat through evaporation and condensation within the closed refrigeration system. The heat may be expelled into the building, outdoors, or into cooling water.

Typical walk-in refrigerator or freezer

Know what you need

To choose the most efficient refrigerator or freezer, consider:

  • the temperature the unit must maintain
  • the functions the unit must perform (refrigeration, freezing or both)
  • the configuration of doors required for access and/or display
  • the speed at which cooling or freezing must occur (for health reasons)

Select for energy efficiency

There are many options that reduce energy transfer and, therefore, energy use:

Insulation

  • better insulation in walls, ceiling and floor
  • better gaskets and sealing materials for doors
  • improved materials, geometries, and manufacturing techniques in panel interface systems for better overall insulating capacity of the envelope

Lighting

  • high efficiency lighting (LEDs) and electronic lighting ballasts
  • fiber optic lighting gathered from rooftop collectors
  • occupancy sensors turn inside lights on only when a person is present

In-and-out

  • vestibule entryways and revolving doors
  • automatic door opening and closing systems
  • air curtains, especially recirculating models, and even strip curtains
  • automatic evaporator fan shut-off whenever the walk-in door is opened

Controls and monitors

  • refrigeration system override for off-peak hours
  • air and water infiltration sensors to monitor condition of insulation
  • evaporator fan control to run at variable speed, or cycle on and off, during periods when the compressor is off

Efficient technologies

  • higher efficiency compressors
  • higher efficiency evaporator and condenser fan blades
  • improved evaporator and condenser coils
  • higher efficiency fan motors, e.g. three-phase, ECMs and PSCs

For an overview of high efficiency food services equipment see our ENERGY STAR Guide for Commercial Kitchens [PDF - 2.1 MB].