Experimental study of non-bonded packed bed active magnetic regenerators with stabilized La(Fe,Mn,Si)13Hy particles

The aim of this study is to develop more stable magnetocaloric regenerators, made from non-epoxy-bonded La(Fe,Mn,Si)₁₃H_y particles to address the instability issues of conventional regenerators with a first-order phase transition. The stabilized magnetocaloric materials are obtained by increasing the α − Fe content at the expense of a small reduction of the adiabatic temperature change. However, the experimental results show that the non-bonded structure improves the regenerator efficiency and reduces pressure drop, potentially compensating for the reduction of the material’s magnetocaloric effect. Compared to epoxy-bonded regenerators, non-bonded regenerators exhibit a larger temperature span (10.2 K at no load) and specific cooling power (27% improvement at a span of 4 K). Due to the elimination of the epoxy, a lower friction factor and higher packing density are obtained. The long-term mechanical and chemical stabilities are verified by comparing specific heat, effectiveness, and pressure drop before and after a test period of more than one year.