Refrigerants

Refrigerants are substances that can be used in the refrigeration cycle of air conditioning and refrigeration equipment because of their thermodynamic properties.

Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are synthetic substances used as refrigerants. These halogenated refrigerants have to be chemically synthesized as they either do not occur in nature at all or only in trace concentrations. CFCs and HCFCs are being phased out under the Montreal Protocol, an international agreement to protect the ozone layer. They have been controlled by the Montreal Protocol since 1987 because of their ozone depleting potential and high global warming potentials.

Different groups of refrigerants and their ozone depletion and global warming potentials

Substance group	Abbreviation	ODP	GWP	Example (refrigerant/foam blowing agent)
Saturated chlorofluorocarbons	CFC	0.6-1	4750-14,400	R11, R12
Saturated hydrochlorofluorocarbons	HCFC	0.02-0.11	77-2310	R22, R141b
Saturated hydrofluorocarbons	HFC	-	124-14,800	R32, R134a
Unsaturated hydrochlorofluorcarbons	u-HCFC	<0.001	0-10	R1233zd
Unsaturated hydrofluorocarbons	u-HFC	-	<1-12	R1234yf, R1234ze, R1234yz
Natural refrigerants		-	0-3	R744 (carbon dioxide) R717 (ammonia) R290 (propane)