Recent developments in room temperature active magnetic regenerative refrigeration

Active magnetic regenerative refrigeration (AMPR) systems represent an environmentally attractive alternative to vapor compression systems that do not use a fluorocarbon working fluid. The AMRR concept has previously been demonstrated using superconducting solenoid magnets that are not practical for small-scale commercial applications. However, recent AMRR prototypes that use more practical permanent magnets have proved that AMRR systems can produce cooling over a useful temperature range with a relatively low magnetic field. In addition, families of materials with large magnetocaloric effects and adjustable Curie temperatures have been developed; these materials may be used to construct layered regenerator beds that may have lower cost and provide higher performance than current materials. This paper reviews recent developments in the field of room temperature magnetic refrigeration and discusses some design issues that may affect practical systems.