refrigerant

When it’s cold outside, the process is reversed: Heat from the chilly outdoor air is extracted and delivered indoors with the help of refrigerants and a compressor.

Methylene chloride will continue to be allowed to make refrigerants as an alternative to other chemicals that produce greenhouse gases and contribute to climate change, Freedhoff said.

A large group of ozone depleting chemicals were responsible - primarily CFCs or chlorofluorocarbons - that were used as refrigerants.

It works by circulating liquid refrigerants with low boiling points through a closed loop, capturing warmth from the air.

Air-source pumps, for example, suck in outdoor air and pass it over tubes containing refrigerant fluids to produce heat.