USA: General Electric (GE) has teamed up with researchers at one of America’s leading research facilities to develop its magnetic refrigeration system.
GE, which earlier this year announced a breakthrough in harnessing the magnetocaloic effect by managing to freeze water, has formed a partnership with Oak Ridge National Laboratory (ORNL) in a cooperative research and development agreement to help develop the technology.
GE’s research team is working to apply the concept of the magnetocaloric effect to domestic refrigerators, replacing conventional vapour compression technology while still reaching the desired cooling temperatures. Instead of traditional refrigerants, the system uses solid refrigerants and water-based fluids.
The MCE approach relies on magnets instead of a compressor to create a magnetic field that agitates particles in the solid refrigerant, causing it to cool. The strength of the magnetic fields determines how cold the solid refrigerant becomes and, in turn, how quickly it cools the refrigerator.
“It’s the equivalent to a gas-powered car moving to electric—that’s the kind of leap we’re making in refrigeration,” said Ed Vineyard, Building Equipment Research Group leader with the Building Technologies Research and Integration Center at ORNL. The center is a Department of Energy user facility aimed at developing energy-efficient building system technologies in partnership with private industry.
Use of magnetics requires changes to the mechanisms through which the refrigerant flows. For instance, ORNL researchers Ayyoub Momen, Omar Abdelaziz and Vineyard are working to determine the new requirements for refrigeration circuit seals and hydraulics.
The ORNL team is also building a “breadboard” prototype refrigerator-freezer: a flexible platform used to evaluate material compatibility and to analyse components including the magnet, generators, motor, pump, heat exchangers, plumbing and leakless rotating valve.
According to GE, the magnetocaloric technology can be applied to other heat pump applications, such as heating, ventilation, and air conditioning (HVAC).
ORNL’s BTRIC staff has partnered with GE on other projects in recent years, including the Geospring heat pump water heater, high EER window air conditioner, and three other high-efficiency appliances. The magnetocaloric refrigerator-freezer project is sponsored by the US Department of Energy’s Building Technologies Office.