Composite Magnetic Refrigerants for an Ericsson Cycle: New Method of Selection Using a Numerical Approach
The efficient operation of an Ericsson cycle requires the magnetic entropy change (AS) be constant as a function of temperature. To realize this condition using composite materials, a numerical method has been developed to determine the optimum proportions of the components. The GdxEr1-x((x = 0.69, 0.90) alloys have been used to investigate the validity of the numerical method. The values of ∆S have been determined from experimental magnetization curves of these alloys, in the 0.1–9 T magnetic field and the 200–290 K range. The calculations have led to the mass ratio y = 0.56 for the composite (Gd0.90Er0.10)y(Gd0.69Er0.31)1-y. The ∆S of this composite is fairly constant in the 225–280 K range. To confirm this result, the magnetization curves of the composite material have been determined experimentally, and the corresponding ∆S was compared with the one predicted numerically. A good agreement was found proving the method’s ability to properly determine the required fractions of the refrigerant’s constituent materials.
KeywordsMagnetic Entropy Change Physical Property Measurement System Refrigeration Cycle Magnetic Refrigerant Optimum Proportion
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