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Using Magnets to Keep Cool: Breakthrough Technology Boosts Energy Efficiency of Refrigerators

July 29, 2014 - 2:13pm

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Researchers demonstrate General Electric's magnetocaloric system. | Photo courtesy of General Electric

Researchers demonstrate General Electric's magnetocaloric system. | Photo courtesy of General Electric

Household refrigerators are essential for keeping food cool and safe. However, these appliances use a lot of energy, and generate emissions that negatively impact the environment. New technology funded by the Energy Department has led to a major breakthrough in refrigeration systems that could yield big energy savings for consumers and greatly reduce carbon pollution.

With help from about $2 million in Energy Department funding through the Recovery Act, General Electric (GE) partnered with Oak Ridge National Laboratory researchers to develop magnetic cooling technology -- an innovative approach that uses a 50-stage system combined with a new type of iron-manganese alloy to remove heat and reduce temperatures by up to 80ºF.

By applying the concept of the magnetocaloric effect (lowering or raising the temperature of material by changing the magnetic field), GE has identified a method for replacing a refrigerator’s conventional vapor compression technology while still providing an effective means for cooling food and beverages.  This system uses a water-based fluid, a more environmentally friendly and cost-effective cooling system, in contrast to traditional refrigerants.  This technology also introduces magnets instead of a traditional compressor. The magnets create a magnetic field that heats up the particles in the regenerator (or heat exchanger). After heat is released -- the byproduct of work being done by the refrigerator-- the magnetic field is removed, causing the refrigerator to cool.

GE’s system has strong magnetocaloric properties, resulting in a temperature drop of about 7 ºF per stage as the water moves through the system.  GE estimates this system could improve a standard refrigerator’s energy efficiency by about 20% and eliminate the need for chemicals that harm the environment. The technology could be introduced to the consumer market in about five years, GE estimates.  Magnetocaloric effect technology also offers the potential to be used in other cooling appliances, or even in heating equipment where heat pumps can be used.

The project is part of the Energy Department’s overall efforts to improve the energy efficiency of appliances, including refrigerators, washers, and dryers. Go to energy.gov/eere/buildings for more information, and visit EnergySaver.gov for tips on how clean energy technologies already on the market can help consumers save money by saving energy.

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