Experimental evaluation of a Gd-based linear reciprocating active magnetic regenerator test apparatus

The present paper describes the design, operation and preliminary results of an active magnetic regenerator test machine. The regenerator consists of twenty eight 0.85 mm thick parallel gadolinium (Gd) plates that form 0.1 mm thick parallel channels with an effective length of 126 mm. The working fluid is water and the magnetic field source is a Halbach array with a maximum flux density of 1.65 T. A maximum temperature span between the hot and cold ends of the regenerator (∆TREG) of 4.45 K and a maximum cooling capacity of 3.9 W were measured in tests without and with a thermal load, respectively. The behavior of ∆TREG as a function of the utilization factor and of the temperature of the hot source is explored in the manuscript. The experimental results are discussed in the light of the fluid flow and heat transfer phenomena taking place in the regenerator.