A high-performance magnetic refrigerator is expected to serve as an alternative technology for air-conditioners in electric vehicles. The high power consumption of conventional air-conditioners in electric vehicles considerably decreases the cruising distance. In the background, the demands of cooling power density, temperature difference between hot and cold sides, COP and transient properties must be high. We have devised a novel system that doesn't require heat-transfer fluid where heat is transported from the cold side to the hot side via well-controlled thermal switches. The heat transfer mechanism has been verified both experimentally and numerically. Furthermore, the superiority of the refrigerating capacities have also been verified by numerical simulation, with specifications of the main constituent parts varied over a wide range. However, several issues remain to be solved in order to draw out even higher potential. Among the issues, a thermal switch with liquid metal driven by electrowetting-on-dielectric (EWOD) has been introduced as an example solution for the thermal switch.
To introduce a recent situation of materials research for mangetocaloric effect at toom temperature, various magnetocaloric materials are compared in terms of the industrial advantage. Some case studies for La(Fe,Si)13-based materials are also introduced with tailoring of magnetic properties in view of system load.