An international team of scientists, led by Bing Li from the Chinese Academy of Sciences, has reported that they have discovered that crystals of a plastic, called neopentyl glycol, have the potential to replace harmful greenhouse gas refrigerants in refrigerators, air conditioners, computer cooling systems and the like.

Between 25 and 30% of the world’s electricity is used for cooling. It is estimated that one kilogram of the refrigerants currently in use contribute as much to the greenhouse effect as two tonnes of carbon dioxide. These gases are released to the atmosphere when the refrigerator or air conditioner is disposed of.

The newly discovered crystal works in a similar way to the gas cooling system used in current refrigerators but does so at the atomic level. Instead of using pressure to change the refrigerant from a gas to a liquid, releasing heat, pressure is used to change the structure of the crystal.

Normally, the atoms of the crystal spin randomly around points within a lattice. Under pressure, the atoms become highly ordered and line up in a crystalline structure. When the pressure is removed, the structure reverts back to the random state, releasing heat.

The cooling performance to comparable to using a gas refrigerant. The plastic crystals can be made cheaply and are able to endure a large number of cooling cycles.

The technology has been demonstrated in the laboratory. The next stage is to develop it for practical use.