Development of 1 kW-class Magnetic Heat Pump

Abstract

Railway Technical Research Institute has been studying a magnetic refrigerator for train air-conditioners. Hydrochlorofluorocarbons (HCFCs) are used in the conventional air-conditioners. The development of HCFC-free systems or the usage of substances which have minimal greenhouse effect is required because the problem with HCFCs is that they cause global warming. Magnetic refrigeration technology has the potential of high efficiency without the use of Freon gases. A prototype magnetic refrigerator has been developed. It consists of fixed active magnetic regenerator (AMR) beds and Halbach-arrayed NdFeB magnets with a peak field of 1.5 Tesla rotating over the beds. Each bed is packed with sphere gadolinium (Gd) or Gdbased compounds. The system has a maximum cooling capacity of 1.4 kW. Several cascade patterns of the packed materials in the AMR beds were evaluated and a maximum temperature span of 21.3 K was obtained.