Active caloric regenerator cycles: an analytic element model.

We describe an analytic model for active caloric regenerator (ACR) cycles using any type of caloric material. An ACR element is defined which provides expressions for cooling power and work input directly without solving the governing partial differential equations for fluid and solid temperature. The ACR performance is determined by fundamental material properties such as specific heat and adiabatic temperature change in addition to the properties that define an effective passive regenerator. The ACR element includes losses due to conduction, convection, and depolarization. We demonstrate the predictive ability of the element model with comparisons of loss mechanisms in an ACR using a first order magnetocaloric material. We then show how the ACR element is used with regenerators made up of layers of different materials with a two-layer ACR example. In addition to providing a clear functional relationship for performance, the element model allows for fast screening of materials, design, and operating conditions.