Refrigeration is based on heat transfer mediums that absorb heat from the area being cooled and transfer it to the outside environment.
The earliest refrigerants were dangerous substances like ammonia. In the 1930s, chlorofluorocarbons (CFCs) like Freon became the standard refrigerant for use in refrigeration systems and even in aerosol cans. When these substances were found to be depleting the earth’s ozone layer, the Montreal Protocol dictated their phaseout and by the mid-1990s, CFCs were largely replaced by hydrofluorocarbons (HFCs).
HFCs don’t deplete the ozone layer, but they were eventually determined to be potent greenhouse gases, thousands of times more planet-warming than carbon dioxide. As a result, the global phaseout of HFCs began in 2016, and have been increasingly replaced by hydrofluoroolefins (HFOs), which are considered a more environmentally-friendly alternative to all their predecessors.
Trying to not be surprised by additional unpleasant discoveries about refrigerants, researchers are studying the potential environmental impacts of HFOs. Researchers at the University of New South Wales in Australia have found that HFOs can break down in the atmosphere and that some small amounts of the resultant products are in fact fluoroforms, which are the HFC with the greatest global warming potential and can stay in the atmosphere for up to 200 years.
That only a small amount of HFC gets into the atmosphere is good, but nevertheless it reveals that the consequences of replacing widely-used chemicals are not a simple matter to determine.
**********
Web Links
Are our refrigerants safe? The lingering questions about the chemicals keeping us cool
Photo, posted July 19, 2021, courtesy of Vernon Air Conditioning via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
