Tuesday, July 06, 2010

#MagnetoCaloric Effect Aims at Cool Future

The magnetocaloric effect permits magnetic fields to quickly cool certain objects, which are currently under study worldwide. Look for applications of the magnetocaloric effect within five years. R.C.J.

Jeff Kortright (left) and Sujoy Roy use soft x-ray resonant magnetic scattering and spectroscopy to study the magnetocaloric effect.

Here is what the Berkeley Lab researchers say about their own work: Scientists [aim to] gain a better understanding of a phenomenon called the giant magnetocaloric effect, in which a changing magnetic field in a material causes its temperature to drop precipitously. Fundamental research conducted at facilities like Berkeley Lab's Advanced Light Source could lead to the energy-saving technologies of tomorrow, such as a magnetic fridge...Although the magnetocaloric effect was discovered more than 100 years ago, scientists have only recently eyed it as a way to develop solid-state refrigerators. A magnetic fridge would be quiet and compact. It wouldn’t require hydrofluorocarbons used in conventional refrigeration systems. Hydrofluorocarbons are potent greenhouse gases if they escape into the atmosphere. And a magnetic fridge would consume less electricity than today’s fridges, which account for eight percent of a family’s utility bill according to the U.S. Environmental Protection Agency. The magnetocaloric effect could also cool laptops more efficiently than battery-draining fans, serve as the refrigerant in vehicle air conditioners, and be used in industrial refrigeration. There’ve been successes over the years, but no big advances that put the magnetocaloric effect within reach of consumers. The trick is finding alloys that undergo the phenomenon under the conditions found in your kitchen or car. This means at room temperature and without requiring too much energy. It must also be affordable. The hunt for ideal candidates has picked up speed over the past decade, with research taking place in the private sector as well as several universities and Department of Energy national laboratories. Much of the focus is on alloys that exhibit not just any magnetocaloric effect, but a “giant” magnetocaloric effect, so named because they exhibit a large entropy change...
Full Text: