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A NEW “smart metal” developed at the University of Maryland, US, is up to 175% more efficient as a refrigerant than those currently in use.

A team led by Ichiro Takeuchi, a materials science professor at Maryland, have developed the solid coolant as a replacement for more commonly used liquid coolants. The researchers describe the material, a metal alloy, as a “thermally elastic” shape memory alloy.

Conventional liquid refrigerants – chlorofluorocarbons (CFCs) and the various alternatives that have been introduced to prevent damage to the ozone layer – absorb and release heat when they switch phase between liquid and vapour in a compression system. The new two-state alloy works in a similar way, absorbing or creating heat as required, but is far more energy efficient and has a smaller operational footprint. The team is testing the alloy in a 90kg prototype air conditioning system to determine its commercial viability.

"The approach is expected to increase cooling efficiency 175%, reduce US carbon dioxide emissions by 250m metric tons per year, and replace liquid refrigerants that can cause environmental degradation in their own right," says Eric Wachsman, director of the University of Maryland Energy Research Center (UMERC).

The research was funded with a $500,000 grant from the US Department of Energy as part of its Advanced Research Projects Agency-Energy (ARPA-E) programme which is designed to bring “game-changing” technologies to the market.