Fridges that run without electricity
An Oxford electrical engineer has come up with a refrigerator that runs without electricity. Not his own idea. He has based it on a model invented by Albert Einstein in 1930. Einstein and his colleague, Hungarian physicist Leo Szilard, patented a fridge that had no moving parts and used only pressurised gases to keep things cold. The idea is to eventually stop using modern refrigerators, which use gas that harm the environment. They work by compressing and expanding man-made greenhouse gases called freons - far more damaging than carbon dioxide.
Malcolm McCulloch, an electrical engineer at Oxford who works on green technologies, is leading a three-year project to develop fridges that can be used in places without electricity. Einstein and Szilard's idea avoids the need for freons. It uses ammonia, butane and water and takes advantage of the fact that liquids boil at lower temperatures when the air pressure around them is lower.
He is not the only one interested in environment-friendly fridges. Engineers working at a Cambridge-based start-up company, Camfridge, are currently using magnetic fields, instead of gas, to cool things.
