Low Cost Alloys for Magnetocaloric Refrigeration

Replacement of petroleum based vehicles with fuel cell electric vehicles operating on hydrogen produced from domestically available resources would dramatically decrease emissions of greenhouse gases and other pollutants as well as reduce dependence on oil from politically volatile regions of the world. One major inhibitor to a hydrogen society is the lack of infrastructure, which requires hydrogen liquefaction refrigeration systems to provide safe and economical storage and transportation of this fuel. One of the more promising technologies of interest for hydrogen liquefaction is magnetic refrigeration due to its high efficiency particularly at cryogenic temperatures. Magnetic Refrigeration utilizes the magnetocaloric effect (MCE), which is the temperature variation of a magnetic material after exposure to a magnetic field. There are several major issues that need to be solved to move this technology forward. One issue inhibiting magnetic refrigeration progress is the lack of commercially available low cost MCE materials that will actually function, for a long period of time, in a magnetic refrigeration environment. During the Phase I and II efforts novel low cost compositions with 2nd order, hysteresis-free response to cover the entire 9-300 K temperature range were successfully discovered. These materials are now commercially available in small quantities on www.geandr.com webstore, and they are the highest performance materials on the market. Another major issue inhibiting magnetic refrigeration from moving forward is that very little work has been done designing and engineering actual systems which utilize the MCE mechanism. The Phase IIB effort will bridge the gap between material science and engineering application. We will use our MCE materials and build a high efficiency (>50% of Carnot) magnetic refrigeration system to demonstrate small scale liquefaction. A variety of commercial opportunities for high efficiency small scale liquefaction systems exist, however, one major opportunity, which would also be an enabling technology for fuel cell electric vehicles is the reduction/elimination of boil-off losses at hydrogen fueling stations. The boil-off losses create logistical challenges that inhibit scale-up. Economical and efficient systems to re-liquefy H2 would solve these problems. If successfully implemented, this could have a major impact on the automobile industry. Further, successful demonstration of a high-efficiency cost-competitive system for a relevant commercial application would validate this technology and stimulate industrial innovation with the potential to advance the state-of-the-art in all refrigeration technologies.