An Analytical Approach for Computing the Coefficient of Refrigeration Performance in Giant Inverse Magnetocaloric Materials

Abstract

An analytical approach for computing the coefficient of refrigeration performance (CRP) was described for materials that exhibited a giant inverse magnetocaloric effect (MCE), and their governing thermodynamics were reviewed. The approach defines the magnetic work input using thermodynamic relationships rather than isothermal magnetization data discretized from the literature. The CRP was computed for only cyclically reversible temperature and entropy changes in materials that exhibited thermal hysteresis by placing a limit on their operating temperature in a thermodynamic cycle. The analytical CRP serves to link meaningful material properties in first-order MCE refrigerants to their potential work and efficiency and can be employed as a metric to compare the behaviors of dissimilar alloy compositions or for materials design. We found that an optimum in the CRP may exist that depends on the applied field level and Clausius–Clapeyron (CC) slope. Moreover, through a large literature review of NiMn-based materials, we note that NiMn(In/Sn) alloys offer the most promising materials properties for applications within the bounds of the developed framework.