Development of Low Cost Magnetocaloric Nanomaterials for Sub 80oK Refrigeration Applications

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.
Statement of how this problem is being addressed: 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 rare-earth and very expensive. Therefore, the focus of this proposal is to develop rare-earth free or low cost rare-earth MCE materials specifically for hydrogen liquefaction systems. Small changes in the composition of the MCE material shift its MCE response temperature, allowing optimization to the desired temperature range (~20K). The use of nano-grained structures allows broader temperature response range along with increased cooling capacity. During the Phase I effort, nano-grained compositions of low cost Mn-based Heusler alloys, and La-based alloys will be synthesized and optimized for near 20K refrigeration.
Commercial Applications and Other Benefits:
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 these 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.
Key Words:
Magnetocaloric Materials, Hydrogen Liquefaction, Magnetic Refrigeration, Nanomaterials