Speaker
Description
One major inhibitor to a hydrogen society is economical systems to support safe storage and transportation of this fuel. Magnetic refrigeration has emerged as a promising technology for hydrogen liquefaction due to its potential high efficiency and environmentally friendly operation. Magnetic refrigeration utilizes the magnetocaloric effect (MCE), which is the temperature variation of a magnetic material after exposure to a magnetic field. Several critical challenges exist for developing low cost magnetic refrigerators. Challenges specific to MCE materials include the cost, availability, stability, and performance of the material in a refrigeration device (i.e. where fast magnetization and demagnetization cycles are required). The best known MCE materials for sub 80K applications are expensive rare-earth. We are developing low cost rare-earth Ce- and Nd- based ternary alloys which yield only 2nd order phase transitions (no hysteresis) and performance (DS) higher than current best materials. With small changes in the composition, the MCE response temperature can be shifted between 10K-50K, allowing system based optimization for various liquefaction applications. Work is ongoing to optimize processing, performance, and shaping of the MCE materials into a useable structure for magnetic refrigeration devices.