Mechanical Refrigeration

Industry: Fruit and Vegetables (NAICS 3114) Dairy (NAICS 3115) Meat (NAICS 3116) Baking (NAICS 3118) Snack Foods (NAICS 3119)

NAICS process:

almost all

Process Brief: Cooling is provided by a system in which a refrigerant is compressed and allowed to expand within a closed loop.

Energy source: Electricity

Energy Intensity:

Mechanical refrigeration is the workhouse of the food industry, accounting for 90% of industry chilling applications. The basic technology, which is more than 100 years old, uses a refrigerant circulating in a closed loop to move heat from one part of the system to another. The loop includes four elements: compressor, condenser, expansion valve, and evaporator. The compressor, usually driven by an electric motor, compresses the refrigerant to a hot, high-pressure gaseous state. The refrigerant releases heat in the condenser (like a radiator) where it becomes a high-pressure liquid. The expansion valve acts as a throttle for the refrigerant, cooling it and making it a low-pressure liquid downstream from the valve. The refrigerant becomes a gas in the evaporator and absorbs a great deal of heat.

The energy efficiency of an industrial refrigerator is the Coefficient of Performance (COP) and can range from less than 1 to 3 or more. The most common refrigerant is ammonia. Natural gas engines, instead of electric motors, have been installed on some mechanical refrigeration systems.

Source: Overview GRI-03/0075;