Numerical simulations and experimental tests of Gd-Y multi-layered active magnetic regenerators.

Magnetic cooling still needs to overcome some challenges to become a commercially competitive technology. One of these challenges is to make the best use of the magnetocaloric effect of the material in the active magnetic regenerator (AMR). In this work, we have evaluated through 1-D numerical simulations different parameters that may be used to optimize a multi-layered AMR composed of second-order Gd-Y alloys. We have characterized their thermo-physical properties, such as heat capacity, magnetization, magnetic entropy change and adiabatic temperature change as a function of temperature and magnetic field. The AMR parameters, such as number of layers and layer length fraction, were varied in order to maximize the cooling capacity for a fixed temperature span. An experimental validation of the numerical simulations was carried out in an AMR test apparatus using a regenerator bed composed by two and three layers of Gd-Y spheres with different Curie temperatures.