Many refrigerators and air conditioners use a class of chemicals called hydrofluorocarbons as refrigerants or in insulating foam. These compounds happen to be extremely powerful greenhouse gases, thousands of times more powerful than carbon dioxide, and their use is going up.

Researchers and some companies are now coming up with ways to use fewer HFCs, if any, in cooling systems. They presented some of their work as the U.S. Environmental Protection Agency rolled out new rules to keep these gases in check.

EPA Administrator Gina McCarthy (left) and Energy Secretary Ernest Moniz (second from left) speak to a scientist from Oak Ridge National Laboratory about refrigeration research.