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. Magnetic Refrigeration utilizes the magnetocaloric effect (MCE), which is the temperature variation of a magnetic material after exposure to a magnetic field. A critical challenge of developing low cost magnetic refrigerators is the cost and availability of MCE materials, which are typically expensive rare-earth. During the Phase I effort, promising low cost high performance MCE materials were discovered which function at sub 50K temperature range, which encompasses the hydrogen liquefaction temperature (20K). The Phase II will involve a simultaneous effort of optimizing processing for the sub 50K materials to meet commercial requirements, while also continuing to identify promising MCE alloys for >50K applications. The proposed research has the potential to contribute to a fundamental understanding of MCE within nanoscience and also advance the state-of-the-art in refrigeration technologies. The proposed low cost MCE materials would reduce the MCE material cost for hydrogen liquefaction systems by greater than 95%, offering an enormous commercial opportunity ((>$20M annual U.S. gross sales), and opening the door for reliable, low cost, and energy-efficient hydrogen liquefaction systems. Additionally, all working MCE materials developed during this research will be made commercially available for online purchase in small quantities. This will accelerate the development of innovative magnetic refrigeration technologies for all temperature applications: hydrogen liquefaction (20K), nitrogen liquefaction (80K), space applications (100-200K), and room temperature refrigeration and air conditioning.