A comprehensive study of a versatile magnetic refrigeration demonstrator

• A new versatile room temperature magnetic refrigeration system was built.
• A comprehensive study was done with 30 g of Gd spheres of 0.2–0.4 mm diameter.
• The maximum T span achieved was 20 K (no heat load) and cooling power 6 W (no T span).
• Results from modified AMR cycles show potential to improve the cooling behaviour.

A versatile room temperature reciprocating magnetic refrigeration demonstrator has been designed, built and tested in order to evaluate the influence of different running parameters and to check suitable magnetocaloric materials for cooling at room temperature. A comprehensive study has been done with Gd spheres of 0.2–0.4 mm diameter arranged as a double regenerator with 15 g each. A Halbach Nd2e14B permanent magnet with a slot of 10 mm width has been used to generate the magnetic field with a maximum value of 1.4 T. The heat transfer fluid is a mixture of water and ethylene glycol in a 75–25 percentage. The demonstrator achieves a maximum no-load temperature span close to 20 K, with a regeneration ratio of ξ   = 4.1, and a maximum cooling power Q˙c=6 W at zero temperature span. COP values have been shown and different thermodynamic AMR cycles have been studied looking for the best parameters.