Ionic cooling offers way to end greenhouse gas use in refrigeration

A heat transfer protocol that could end the use of greenhouse gases in refrigeration has been demonstrated by US researchers. The technique, which harnesses the decrease in a liquid’s melting point when a salt is dissolved in it, shows notable advantages over some other proposed alternative refrigeration technologies.

Heat naturally flows from hot to cold. Refrigeration and heat pumps use energy to reverse this flow. Today’s refrigerators use vapour compression, depending on the cycling of a refrigerant between a low-pressure cold reservoir – where it evaporates – and a high-pressure hot reservoir – where it condenses – to move heat against the thermal gradient. However, many refrigerants that have been used are chloroflourocarbons, and have been banned to protect the ozone layer. Replacements such as hydrofluorocarbons are potent greenhouse gases and hydrofluoro-olefins may break down to toxic byproducts.