Following the phase-out of CFC refrigerants under the Montreal Protocol, the most common replacements were HCFCs and later HFCs.
Although the detrimental effects of these substances towards the ozone layer are significantly reduced or eliminated, some do pose a significant threat to global warming.
Today HFC-134a is by far one of the most popular replacement refrigerants on the market.
However, its global warming potential is 1,300 times more powerful than carbon dioxide over a 100-year period.
Therefore, these replacement products are regulated as a class 3 substance under MR 103/94 and must be managed the same way as CFC refrigerants to ensure environmental protection.
Another up and coming replacement refrigerant is hydroflouroolefin, or HFO.
HFOs contain hydrogen, fluorine and carbon like the HFCs, but they are distinctly different. They are olefins, which mean they have very short atmospheric lifetimes of a few days, leading to distinct environmental benefits. HFOs offer many of the key properties of existing HFCs, but with very low GWPs (Global Warming Potential).
HFOs with their marginal flammability characteristics or in mixtures with HFCs, are expected to be used in applications where the highly flammable hydrocarbons (HCs) are not appropriate.
HFOs are viable low GWP fluids for use in a range of applications. The safety and performance in use of these fluids and their attractive environmental properties hold considerable promise to improve the environmental performance of air-conditioning and refrigeration systems as well as in other applications.– www.fluorocarbons.org
For more detailed information, see a recent study concerning HFOs.