Thermal effectiveness of active caloric regenerators

Caloric materials respond to external field variations such as magnetic, stress, and electric. A simple caloric cycle uses entropy and temperature changes resulting from a single field variation to provide useful transfers of work and heat. An active regenerator cycle increases operating range and efficiency of a caloric material when property variations are appropriately matched to design conditions. However, the variability of material properties, wide range of design variables, and non-linear interactions complicate design of devices. Simplified analytic models are needed to increase understanding and quantify potential of calorics for commercial heat pumps and engines. An analytic model of a generic active caloric regenerator operating as a heat pump or engine is described. A thermal effectiveness is defined as an analytic function of operating, design, and material parameters.