Microchannel Magnetic Coolers with Negative Magnetocaloric Effect

The recent discovery of a negative magnetocaloric effect in CoMnT1-xT¿x alloys (where T, T¿ = Si, Ge, Sn) at room temperature opens new prospects for the development of high-efficiency solid micro-cooling devices. This project will combine these novel alloys with cutting edge technology for microchannel regenerators to develop lightweight, compact, low cost, and environmentally friendly cooling devices. Phase I explored the use of solid microchannel regenerator cartridges instead of traditional regenerator beds packed with spheres. Technologies were demonstrated for the fabrication of magnetocaloric CoMnT1-xT¿x powders and for the fabrication of microchannel structures from these powders. The basic requirements (with respect to source materials, methods of deformation, and consolidation of the powders) needed to preserve the magnetocaloric effect in the microchannel structures produced from these powders were established. Phase II will optimize and scale up the fabrication technologies, both for the CoMnT1-xT¿x powders and for the microchannel regenerators for magnetic coolers. The microchannel magnetocaloric regenerators will be manufactured and tested with respect to thermal efficiency and mechanical stability in active magnetic cooling systems. Commercial Applications and Other Benefits as described by the awardee: Solid state cooling devices hold a promise to revolutionize the current market for refrigeration systems. Magnetocaloric materials would enable the creation of compact refrigeration units that run silently and vibration free, and most importantly, without the use of ozone-depleting gases. Magnetocaloric coolers should provide the cooling power required for markets such as home refrigerators, air conditioning, electronics cooling, and fluid chilling.