Researchers working in GE labs have used special magnetic materials to generate temperatures cold enough to freeze water in a breakthrough that could find its way into commercial refrigerators by the end of the decade. (Video: General Electric).
Researchers at General Electric have unveiled a new refrigerant system utilizing special magnetic materials that could be up to 20 percent more efficient than current refrigeration technology.
The system takes advantage of a phenomenon known as the magnetocaloric effect, which was discovered in the late 1800s by German physicist Emil Warburg after he observed that certain metals would heat up when placed near magnets and cool down when taken away.
While scientists have long been intrigued by the magnetocaloric effect, practical applications have been rather limited due to the availability of necessary materials. Last year, European researchers demonstrated the use of the magnetocaloric effect for the thermal management of computer chips and other miniaturized devices using materials comprised of lanthanum, calcium, manganese and oxygen. Now, GE scientists have managed to achieve a similar breakthrough in the field of commercial refrigeration.
“This is a big deal,” Venkat Venkatakrishnan, a leader of the research team, said. “We are on the cusp of the next refrigeration revolution.”
The system uses a water-based fluid flowing through a series of magnets to transfer heat, instead of a chemical refrigerant and compressor. According to the researchers, the magnets are arranged in a cascade, where each step lowers the temperature just slightly.
While progress was initially slow—it took the team five years to achieve cooling of just 2 degrees Fahrenheit—the research was expedited by the GE team’s creation of a new type of nickel-manganese alloy for magnets that could function at room temperatures. Today, they are capable of reducing temperature by 80 degrees.
The GE team has already run demonstrations for experts from the Department of Energy, attended by staffers from the White House and the EPA, and is currently working to achieve a 100-degree drop in temperature at low power.
“Nobody in the world has done this type of multi-stage cooling,” Venkatakrishnan said. “We believe we are the first people who shrunk it enough so that it can be transported and shown. We were also the first to go below freezing with the stages.”
