Initial experimental results from a rotary permanent magnet magnetic refrigerator

• A rotary permanent magnet magnetic refrigerator has been designed and built.
• Gadolinium spheres have been used as refrigerant.
• A new architecture for the AMR refrigerator has been proposed.
• First experiments under no added thermal load have been performed.

In this paper, a novel rotary magnetic refrigerator is described, and initial experimental results are presented. The prototype employs a two-pole magnetic system based on a double U configuration of permanent magnets with an air gap of 43 mm and 1.25 T. The magnetocaloric refrigerant is confined within eight static regenerator enclosures, which are alternatively magnetized and demagnetized with the rotation of the magnets. A rotary valve mechanically coupled with the field generator imparts the direction of heat transfer fluid through the regenerators. Using a total mass of 1.20 kg of gadolinium spheres (of 400–500 microns) as refrigerant and distilled water as regenerating fluid, the device produced a maximum temperature span of 13.5 K under zero applied thermal load with an utilization factor of 1.40 and a heat rejection temperature of 298 K.