Various Definitions Regarding Refrigerators

Absorption		A process in which energy (heat) is taken up by a liquid or solid.
Compressor		This is a pump which compresses refrigerant gas, and consequently heats the gas.
Condensation		A change of state from gas or vapour to liquid.
Evaporation		A change of state from solid or liquid to gas or vapour. It occurs when some molecules of a liquid have enough energy to escape into the gas phase and this has an overall cooling effect on the liquid.
Expansion		The increase of volume of a sample of substance.
Intermediate temperature		A temperature somewhere between hot and cold.
Refrigerant		A chemical substance used as a fluid in a refrigeration system. There are many different types of fluid used, depending on the system design. Most commonly used are hydrofluorocarbons (HFCs) and hydrocarbons (HCs).
Refrigeration		This is the transfer of heat from a substance to be cooled to somewhere else. Heat flows naturally from a warm substance to a colder one eg fish can be cooled by surrounding it with packing ice.
Restrictor		Something that restricts the flow of a gas or liquid.
Sublimation		This is when a solid turns to vapour without going through the liquid phase. For example, you can see solid carbon dioxide (CO2) turning to vapour when it melts without producing a liquid (dry ice).
Thermal Insulation		A means of preventing or reducing the transfer of thermal energy (heat). Good insulators are foam, wool, and vacuums.
Vapour		A substance in a gas state that has reached a temperature at which it could become a liquid just by the application of pressure. It is usually still in contact with the liquid from which it was formed.
Ventilation		The addition of fresh air.