Experimental investigation on refrigeration performance of a reciprocating active magnetic regenerator of room temperature magnetic refrigeration

Room temperature magnetic refrigeration has been proved to be a feasible refrigerating technology and has a prosperous application potential. In this research, magnetocaloric effect (MCE) of metal gadolinium is measured and the metal is prepared from ingot to granular state by method of hydriding–ball milling–dehydriding. The other compound, Gd₅Si₂Ge₂ alloy, is also prepared into grains by mechanical comminuting and its magnetocaloric property is obtained. An experimental system of room temperature magnetic refrigeration is established, and three kinds of magnetic refrigerant (MR I: 0.3 mm mean diameter gadolinium particle, MR II: 0.55 mm mean diameter gadolinium particle and MR III: 0.3–0.75 mm Gd₅Si₂Ge₂ alloy particle) are employed in AMR. Performance experiments of AMR system under various temperature range, temperature span, flow rate, and flow period conditions are investigated. The results indicate that AMR adopting MR I, II, III can generate a maximum refrigerating capacity of 18.7 W, 17.8 W, and 10.3 W, respectively, under a 3 K temperature span. With the increasing temperature span, the capacity decreases. MR I and MR II have an equivalent refrigerating ability higher than MR III.