Magnetocaloric properties of spheroidal La(Fe,Mn,Si)(13)H-y granules and their performance in epoxy-bonded active magnetic regenerators

Magnetic cooling has been researched as an alternative near room-temperature refrigeration technology for the past two decades. However, one of its greatest limitations is the lack of materials which can be properly shaped for optimal thermal-hydraulic performance while maintaining a substantial magnetocaloric effect at moderate fields (i.e., between 1 and 2 T) and remaining mechanically (and chemically) stable. In this paper, we thoroughly characterized a commercially accessible La(Fe,Mn,Si)(13)H-y material (available as spheroidal granules), in terms of its magnetocaloric properties and thermal-hydraulic performance in an Active Magnetic Regenerator (AMR) device. The regenerator bed built from epoxy-bonded spheroidal particles endured dozens of hours of operation in AMR cycles without any noticeable degradation of their mechanical integrity, thanks to a comparatively larger alpha-Fe content and granule porosity. As for the magnetic cooling performance, the AMR reached zero-span specific cooling capacities as high as 300 W kg(-1). A 1-D two-temperature approach AMR model predicted the performance data with average deviations smaller than 7% for the zero-span specific cooling capacity and 5% for the AMR pressure drop.