Refrigerant

A refrigerant is a compound used in a heat cycle that undergoes a phase change from a gas to a liquid and back. The two main uses of refrigerants are refrigerators/freezers and air conditioners.

Related Topics:
Heat cycle - Phase change - Gas - Liquid - Refrigerator - Freezer - Air conditioner

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The ideal refrigerant has good thermodynamic properties, is noncorrosive, and safe. The desired thermodynamic properties are a boiling point somewhat below the target temperature, a high heat of vaporization, a moderate density in liquid form, and a relatively high density in gasous form. Since boiling point and gas density are affected by pressure, refrigerants may be made more suitable for a particular application by choice of operating pressure.

Related Topics:
Thermodynamic - Boiling point - Heat of vaporization - Density - Pressure

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Corrosion properties are a matter of materials compatibility with the components used for the compressor, piping, evaporator, and condenser. Saftey considerations include toxicity and flammability.

Related Topics:
Compressor - Piping - Evaporator - Condenser - Toxicity - Flammability

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Until concerns about depletion of the ozone layer arose in the 1980s, the most widely used refrigerants were the halomethanes R-12 and R-22, with R-12 being more common in automotive air conditioning and small refrigerators, and R-22 being used for residential and light commercial air conditioning, refrigerators, and freezers. Some very early systems used R-11 because its low boiling point allows low-pressure systems to be constructed, reducing the mechanical strength required for components. R-134a and certain blends are now replacing chlorinated compounds.

Related Topics:
Ozone layer - Halomethane - R-12 - R-22 - R-11 - R-134a

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