Performance characteristics of magnetic Brayton refrigeration cycles using Gd, Gd0.74Tb0.26 and (Gd3.5Tb1.5)Si4 as the working substance

Based on the experimental characteristics of the iso-field heat capacity changing with temperature for the room-temperature magnetic refrigeration materials Gd, Gd0.74Tb0.26, and (Gd3.5Tb1.5)Si-4, the corresponding entropy versus temperature curves are calculated and presented, the regenerative magnetic Brayton refrigeration cycles, using these magnetic materials as the working substances, are established. The non-perfect regenerative heat quantity, net cooling quantity, released heat quantity, coefficient of performance (COP) and other performance parameters of these magnetic Brayton refrigeration cycles are analyzed and calculated. Furthermore, the performance characteristics of the Brayton refrigeration cycles employing Gd, Gd0.74Tb0.26, and (Gd3.5Tb1.5)Si-4 as the working substance are evaluated and compared, the influence of non-perfect regenerative heat on the performance characteristics of these magnetic Brayton refrigeration cycles is revealed. (C) 2011 Elsevier Ltd and IIR. All rights reserved.