Materials for Magnetocaloric Applications
Air conditioning and refrigeration are two of the most energy-intensive technologies deployed today. Currently, cooling accounts for 20% of U.S. electricity consumption. In addition to the carbon impact of its energy intensity, cooling can lead to environmentally damaging leaks of synthetic refrigerant. Energy-efficient cooling technologies and new materials will help address this growing energy and environmental challenge.
Project Innovation + Advantages:
Northeastern University, in partnership with the Ames Laboratory, will evaluate a range of new magnetocaloric compounds (AlT2X2) for potential application in room-temperature magnetic cooling. Magnetic refrigeration is an environmentally friendly alternative to conventional vapor-compression cooling technology. The magnetocaloric effect is triggered by application and removal of an applied magnetic field—adjusting the magnetic field translates into an adjustment in the temperature of the material. The benchmark magnetocaloric materials are based on the rare earth metal gadolinium (Gd), but gadolinium is scarce in the earth's crust and prohibitively expensive. Other magnetocaloric materials have similar rarity and cost constraints, or are brittle and undergo large volume changes during magnetic transition. Volume changes are problematic because a magnetocaloric working material must maintain mechanical and magnetic integrity over 300 million cycles in a ten-year lifetime. The Northeastern-led team is proposing to explore new magnetocaloric materials, AlT2X2 (where T=Fe, Mn, and/or Co, and X = B and/or C) comprised of abundant, non-toxic elements that can undergo a structural transition near room temperature. The material is projected to meet or exceed the performance of other candidate magnetocaloric materials due to its potential ease of fabrication, corrosion resistance, high mechanical integrity maintained through caloric phase change, and low heat capacity that fosters effective heat transfer. The project objectives are to ascertain the most promising compositions and magnetic field and temperature combinations to realize the optimal magnetocaloric response in this compound.