It’s an old idea, but General Electric’s advances in magnet technology could lead to a magnetic refrigerator that’s 20% more efficient than today’s refrigerators.
Refrigeration technology has come a long way since the ice box. The first compressor-type refrigerators appeared in the 1920s, and advances in insulation and compressor and evaporator technology have led to the refrigerators that we have today in most every home. Still, refrigeration technology can be improved, and General Electric engineers are going back to an old idea to create a modern magnetic refrigerator.
Currently, refrigerators use a compressor to liquefy a gas refrigerant, typically R-12 or R-134a, which is pumped through tubing in the refrigerator to absorb heat energy. The liquid evaporates and turns back into a gas, pushing out to the tubing on the outside of the refrigerator. Heat is lost to the air, and the refrigerant condenses back into a liquid. 21st Century refrigerators might eliminate the compressor altogether, a more-efficient magnetic refrigerator.
In the 1880s, German physicist Emil Warburg made an interesting discovery. Certain metals would heat up in the presence of a magnetic field, and then cool off again when removed from the magnetic field. Thus was born the idea to build a magnetic heat pump. A magnetic refrigerator, however, has been a long way in coming. It’s taken a team of General Electric scientists, in the United States and Germany, to produce a magnetic heat pump capable of just 2°F drop in temperature. Even Los Alamos National Laboratory, in New Mexico, was only able to achieve a few degrees of cooling, and that with a huge array of superconducting magnets.
General Electric has been able to shrink the technology significantly, but it’s still much too large to put into a household magnetic refrigerator. One interesting development, however, is the advance in cooling power that they’ve been able to achieve with nickel-manganese magnets that work at room temperatures, reducing temperatures by up to 80°F. We still have a while to wait for a home magnetic refrigerator, as well as a price for the new technology, but General Electric estimates that it could be up to 20% more efficient than today’s refrigerator technology.
Image © General Electric (Screenshot)