Knowra Refrigerant Refrigerant A substance circulated through a refrigeration system to absorb heat at low temperature and release it at higher temperature. Many refrigerants repeatedly evaporate and condense as pressure changes.
Vapor-compression refrigeration : A refrigeration cycle that compresses, condenses, expands, and evaporates a working fluid to transfer heat. Most familiar refrigerants circulate through this cycle’s four main components.
Phase transition : A change of matter from one physical state to another, such as liquid to gas. Evaporation and condensation allow refrigerants to absorb and release large amounts of heat.
Air conditioning : The control of indoor temperature, humidity, cleanliness, and air movement. Air conditioners circulate refrigerants to remove heat from indoor air.
Chlorofluorocarbon : A halogenated compound containing carbon, chlorine, and fluorine, formerly widely used as a refrigerant. CFC refrigerants were phased out because they deplete stratospheric ozone.
Montreal Protocol : An international treaty adopted in 1987 to protect the ozone layer by controlling ozone-depleting substances. Its phaseouts drove the replacement of CFC and HCFC refrigerants.
Evaporator : A heat exchanger where a refrigerant absorbs heat as it evaporates. This is where refrigerant takes in heat from the cooled space.
Boiling point : The temperature at which a liquid’s vapor pressure equals the surrounding pressure. A refrigerant’s boiling point shifts with pressure, enabling evaporation at low temperatures.
Heat pump : A device that transfers heat between spaces using work, often through a vapor-compression cycle. Reversing refrigerant flow lets the same system provide heating or cooling.
Hydrochlorofluorocarbon : A compound containing hydrogen, chlorine, fluorine, and carbon, used as a transitional refrigerant. HCFCs deplete less ozone than CFCs but are also being phased out.
Kigali Amendment : A 2016 amendment to the Montreal Protocol that phases down hydrofluorocarbon production and consumption. It targets the climate impact of widely used HFC refrigerants.
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