Energetic comparison of rotation and translation processes in magnetic refrigeration

Abstract

Conventional magnetic refrigeration relies on removing a magnetic refrigerant from a magnetic field to induce demagnetization and an adiabatic change in temperature. An emerging alternative, the demagnetizing field-induced magnetocaloric effect (dRMCE), achieves cooling by rotating a shape-anisotropic refrigerant, using changes in the demagnetizing field instead of physical displacement. A key advantage of this approach is its potential for higher energetic efficiency due to reduced work input. This study evaluates that claim by numerically comparing the magnetic work and heat generation in dRMCE and conventional magnetocaloric effect (MCE). Using finite element analysis, we simulate the demagnetizing field of a thin polycrystalline gadolinium plate in both processes, tracking step-by-step energy changes. Our results demonstrate that, despite producing a smaller adiabatic temperature change (ΔT) and less isothermal heat, the dRMCE consistently outperforms conventional MCE in heat-per-work efficiency, exhibiting 20%–80% higher efficiency in isothermal demagnetization and 40%–80% higher efficiency in adiabatic demagnetization (followed by isomagnetic heating).