Design of permanent-magnet field source for rotary-magnetic refrigeration systems

Magnetic refrigeration based on the magnetocaloric effect (MCE) is a prime candidate for the next generation of cooling systems because it is energy-efficient and environmentally safe. The essential components of magnetic refrigeration are the magnetic field generator and the magnetocaloric material. The cooling power of these devices generally increases as the strength of magnetic field and the MCE of magnetic refrigerant material increase. In order to generate sufficient magnetic field strength, a permanent-magnet array (PMA) can be used. This can be made in a compact form and does not require an external power supply. A PMA based on the Halbach rotation theorem has been designed and constructed for a rotary-magnetic refrigeration system. The magnetic field for a side-opening PMA was over 3 tesla with an air gap of 5.8 mm.