Professor Karl Gschneidner is an Ames Laboratory senior metallurgist and Iowa State University professor who may help bring about new technology for cooling home refrigerators, air conditioning units, and electronics. He works with the Astronautic Corporation of America (Milwaukee, WI) as part of an agreement with Ames Laboratory developing a new refrigerator that uses gadolinium, a ferromagnetic material. The metal heats when exposed to a magnetic field and cools when the field is removed. "A key difference between vapor cycle refrigerators and magnetic refrigerators is the amount of energy loss incurred during the refrigeration cycle," according to Gschneidner. "In current vapor-cycle refrigerators, energy loss during compression and expansion is significant," he notes. "There is virtually no energy loss during magnetizing and demagnetizing in magnetic refrigerators." The new refrigerator has a rare-earth permanent magnet and a wheel with segments coated with the gadolinium. The wheel passes through a gap in the magnet where a concentrated magnetic field heats it up. Circulating water draws the heat from the metal, but the material cools further as a result of the magnetocaloric effect. A second stream of circulating water is cooled by the gadolinium and circulated through the refrigerator's cooling coils. For more information, contact Gshneidner at (515) 294-7931 or go to www.iastate.edu.
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