Experimental characterization of multilayer active magnetic regenerators using first order materials: Multiple points of equilibrium

Multiplepoints of equilibrium (MPE) have recently been observed in single layer active magnetic regenerators (AMRs) using first order magnetic materials (FOMs). Here, we describe experiments using three multilayer MnFeP1-xAsx FOM regenerator beds characterized under a range of applied loads and rejection temperatures. Thermal performance and the impacts of MPE are evaluated via heating and cooling experiments where the rejection (hot side) temperature is varied in a range from 283 K to 300 K. With fixed operating conditions, we find multiple points of equilibrium for steady-state spans as a function of warm rejection temperature. The results indicate a significant impact of MPE on the heating and cooling temperature span for a multilayer MnFeP1-xAsx FOM regenerator. Unlike single material FOM tests where MPEs tend to disappear as load is increased (or span reduced), with the layered AMRs, MPEs can be significant even with small temperature span conditions.