Scientists edge closer to green ACs, fridges

May 16th, 2009 - 11:57 am ICT by IANS  

London, May 16 (IANS) Scientists are closer to making eco-friendly ‘magnetic’ fridges and air conditioning systems a reality.
Magnetic refrigeration technology could provide a ‘green’ alternative to traditional

energy-guzzling gas-compression fridges and air conditioners.

They would use 20 to 30 percent less energy than the most efficient systems currently available, nor rely on ozone-depleting chemicals or greenhouse gases.

In summer months, refrigeration and air conditioning (AC) units alone account for 50 percent of energy use in the US, besides contributing hugely to the planet’s energy consumption.

A magnetic refrigeration system works by applying a magnetic field to a magnetic material - some of the most promising being metallic alloys - causing it to heat up.

This excess heat is removed from the system by water, cooling the material back to its original temperature.

When the magnetic field is removed the material cools down even further, and it is this cooling property that researchers hope to harness for a wide variety of cooling applications.

The technology, based on research funded in Britain by the Engineering and Physical

Sciences Research Council (EPSRC), has been validated in the lab.

But researchers are still looking for improved materials that provide highly efficient cooling at normal room temperatures, so that the technology can be rolled out for commercial use.

They need a material that exhibits dramatic heating and cooling when a magnetic field is applied and removed, which can operate in normal everyday conditions, and which does not lose efficiency when the cooling cycle is repeated time after time.

Lesley Cohen, professor and study co-author, Imperial College, London, explained that by using unique probes, the team, led by James Moore, was able to analyse what happens to different materials level when they are magnetised and de-magnetised.

This enabled the team to pinpoint what makes some materials better candidates for a magnetic fridge system than others, said an Imperial College release.

These findings were published in Friday’s edition of Advanced Materials.

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