A magnetic refrigeration prototype operating with a rare-earth-free magnetic field source.

Abstract

This article presents a new magnetic refrigeration prototype that operates with a rare-earth-free magnetic field source. Its main novelty, in comparison to existing state-of-the-art magnetic prototypes, is the application of a static electromagnet assembly that can regenerate magnetic energy and enables a rapid alternation of the magnetic field, which is one of the crucial operating parameters that could lead towards the future miniaturization of magnetocaloric devices. The presented prototype consists of two electromagnetic assemblies, each containing a packed-bed active magnetic regenerator (AMR) that consists of 30 g of single-layered Gd magnetocaloric material (MCM) in the form of spheres. The prototype was experimentally tested for its performance in terms of temperature span and cooling power. For instance, operating with a single-layered Gd AMR at 4-Hz operating frequency, the prototype produced 114 Wkg-1 of specific cooling power (per MCM mass), while maintaining a temperature span of 5 K below ambient conditions.