Magnetic Refrigerant Materials for Hydrogen Liquefaction by Active Magnetic Regenerative Refrigeration

Abstract

Magnetic refrigerant materials are one of the key factors for governing the cooling performance of magnetic refrigeration systems. In particular, not only the physical properties such as magnetocaloric effects, but also the practical form of the magnetic material are of crucial importance to active magnetic regenerative refrigeration （AMRR）. In this JST-mirai project, the development of several types of magnetic materials that show the large magnetocaloric effects in the temperature range from 20 K to 80 K and fabrication of spherical particles of the materials were conducted. The magnetic properties and magnetocaloric effects between the mother-alloy and spherical particles were compared for HoAl2, ErCo2, and HoB2. Moreover, thermal property and electrical property as well as the shape and size of the materials are discussed from the perspective of their application to the AMRR system for hydrogen liquefaction.