Construction of consistent magnetocaloric materials data for modelling magnetic refrigerators

Abstract

The simulation of magnetocaloric refrigerator behaviour needs a good description of the material properties. Magnetocaloric material data are often given as a function of few values of the external magnetic field applied on a sample, but active material reacts to its internal field. The simulating of the magnetocaloric effect using experimental data can then create some artefacts. In this paper we present an alternative way to obtain material data expressed as a function of the internal magnetic field. This characterization is built on the knowledge of the zero magnetic field heat capacity of second-order phase transition materials such as gadolinium, as well as on the direct measurements of magnetocaloric data. An inverse approach is performed to calculate the data as a function of the internal magnetic field with an improved level of detail. The obtained data allow a better modelling of the magnetocaloric effect in an active magnetic regenerator.