Optimization of active magnetic regenerators with two and three layers of Gd-alloys.

Since the magnetocaloric effect (MCE) of typical materials is large only over a narrow temperature range, layered regenerators can improve the temperature span and thermal performance by using materials with different Curie temperatures to enhance the MCE along the active magnetic regenerator (AMR). In this work, an AMR numerical model was used to simulate layered AMRs. Experimental magnetocaloric properties of Gadolinium (Gd) were employed to simulate different Gd1-xYx alloys. Layered AMRs with two and three layers of Gd spheres were studied by varying the layer length. Single-layer AMRs were simulated for comparison purposes. Two different temperature spans of 15 and 20 K were considered. The layered AMRs were optimized for the largest cooling capacity. The cooling capacity was observed to increase with the number of layers, especially for the 20-K temperature spans, where a 47.3% increase in the cooling capacity was achieved by a three-layer regenerator in comparison with a single-layer regenerator.