hydrofluorocarbons

Hydrofluorocarbons (HFCs) are a class of synthetic organic compounds composed of hydrogen, fluorine and carbon. They do not contain chlorine or bromine and were developed as alternatives to ozone-depleting halocarbons such as CFCs and HCFCs. They are used as refrigerants in air conditioning and heat pumps, as foam blowing agents for polyurethane foams, and as solvents or propellants in some aerosols. They are valued for chemical stability and non-flammability in many varieties, though safety and flammability vary among compounds.

Most HFCs have negligible ozone depletion potential (ODP ≈ 0) but are potent greenhouse gases with long atmospheric lifetimes. Global warming potentials (GWPs) range from hundreds to thousands relative to CO2, and lifetimes span years to decades. Because of their climate impact, many HFCs are subject to international phase-down arrangements.

Regulation and use: HFCs were addressed under the Montreal Protocol framework and its Kigali Amendment, which aims to reduce consumption and production of HFCs with schedules that vary by country. The phase-down has led many regions to pursue alternatives with lower GWPs, such as hydrofluoroolefins (HFOs), natural refrigerants like carbon dioxide and ammonia, and more energy-efficient equipment.

Common examples and blends: HFC-134a (1,1,1,2-tetrafluoroethane) is widely used in automotive and residential refrigeration; HFC-32 (difluoromethane) is another refrigerant; HFC-125 (pentafluoroethane) and blends such as R-410A (a mixture of HFC-32 and HFC-125) are common in air conditioning. See also: HFO refrigerants, Kigali Amendment.