Experimental and numerical results of a high frequency rotating active magnetic refrigerator

Experimental results for a recently developed prototype magnetic refrigeration device at The Technical University of Denmark (DTU) were obtained and compared with numerical simulation results. A continuously rotating active magnetic regenerator (AMR) using 2.8 kg packed sphere regenerators of commercial grade gadolinium (Gd) was employed. With operating frequencies up to 10 Hz and volumetric flow rates up to 600 L/h, the prototype has shown high performance and the results are consistent with predictions from numerical modelling. Magnetocaloric properties of the Gd spheres were obtained experimentally and implemented in a one-dimensional numerical AMR model that includes also the parasitic losses from the prototype. The temperature span for a thermal load of 200 W as a function of frequency was measured and modelled. Moreover, the temperature span dependence on the cooling capacity as a function of cycle frequency was determined. It was found that thermal losses increase as the frequency increases. Therefore, a detailed study of these parasitic losses was carried out experimentally and numerically.