Refrigeration and Air Conditioning Terminology

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ASHRAE

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American Society of Heating, Refrigerating, and Air-Conditioning Engineers

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Azeotropic

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A blended refrigerant that behaves like a single pure refrigerant because all components evaporate and condense at the same temperature and pressure, so its composition does not change during phase change.

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Chiller

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A large piece of mechanical equipment that removes heat from a liquid (usually water or a glycol-water mix), which is then circulated through a building to provide air conditioning or process cooling.

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Class 1 refrigerant

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CFCs (chlorofluorocarbons) that contain chlorine, have a high ozone-depletion potential (ODP), and are strictly regulated and phased out under the Clean Air Act and the Montreal Protocol.

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Class 2 Refrigerant

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A refrigerant that exhibits lower flammability but higher toxicity compared to Class I refrigerants, according to ASHRAE Standard 34 safety classifications.

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Deep Vacuum

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The process of evacuating a refrigeration or air conditioning system to a very low absolute pressure (usually 500 microns or lower) using a vacuum pump, in order to remove air, moisture, and non-condensables before charging the system with refrigerant.

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Evacuation

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The process of using a vacuum pump to remove air, moisture, and non-condensables from a refrigeration or air conditioning system before charging it with refrigerant.

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Fractionation

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The change in the composition of a blended refrigerant when it leaks or boils off unevenly, because the individual refrigerants in the blend have different boiling points.

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Leak Rate

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The amount of refrigerant that escapes from a refrigeration or air conditioning system over a specific period of time, usually expressed as a percentage of the system’s total refrigerant charge per year.

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Line set

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A pair of insulated copper refrigerant lines that connect the outdoor condenser unit to the indoor evaporator coil or air handler.