Heat pump the brand name Freon, a trademark of DuPont. Its manufacture is now banned or severely restricted by the Montreal Protocol of August 1987 because of the damage that CFCs cause to the ozone layer if released into the atmosphere. One widely adopted replacement refrigerant is the hydrofluorocarbon (HFC) known as R-134a (1,1,1,2-tetrafluoroethane). Heat pumps using R-134a replaced R-12 (dichlorodifluoromethane) and have similar thermodynamic properties but with insignificant ozone depletion potential and a somewhat lower global warming potential. Other substances such as liquid R-717 ammonia are widely used in large-scale systems, or occasionally the less corrosive but more flammable propane or
Montreal Protocol Mexico following with a similar proposal in 2010. After seven years of negotiations, in October 2016 at the 28th Meeting of the Parties to the Montreal Protocol in Kigali, the Parties to the Montreal Protocol adopted the Kigali Amendment whereby the Parties agreed to phasedown HFCs under the Montreal Protocol. The amendment to the legally-binding Montreal Protocol will ensure that industrialised countries bring down their HFC production and consumption by at least 85 per cent compared to their annual average values in the period 2011-2013. A group of developing countries including China, Brazil and South Africa are mandated to reduce