Magnetic Refrigerators

Researchers at the Technical University of Denmark have invented a new method of magnetic cooling technology that brings a whole new meeting to refrigerator magnets. Scientists have been able to drop the temperature of a room from 20° C to 11° C by taking the heat energy from opposing magnetic fields and thermodynamically reversing it to a cooler temperature. DTU researchers will use this technology to create a prototype refrigerator that cools itself using only magnets. According to research from Risø National Laboratory, magnetic refrigerators would be silent and their cooling cycles could be up to 60% more efficient than traditional refrigerators!

Here’s how it works:

The magnetocaloric material is magnetized by a magnet and the temperature increases. The material cools by giving off heat to the surroundings through a heat exchanger. The magnetic field is removed and the temperature of the material drops further.
Finally, the material takes up heat from the cold side heat exchanger (”the inside of the refrigerator”) thus cooling it. Then the cycle starts over again.

Such a magnetic refrigerator has a number of advantages compared to conventional refrigerators, e.g. environmentally hazardous refrigeration gasses such as HFC (hydroflourocarbons) or ammonia are avoided, and higher efficiencies are possible.

Despite the promise of this technology, don’t expect to be finding a magnet-powered refrigerator on the market any time soon. It probably isn’t realistic to believe that magnetic cooling technology will be immediately available for consumer use, especially as refrigerator manufacturers have brought prices down so much in the past few years. Regardless, the idea is wonderful and the technology fascinating, for the scientifically-inclined.