Integrated design of a magnetic circuit and an active magnetic regenerator for a 100-W compact device.

In this work, we integrate a 1D active magnetic regenerator (AMR) model with a model of a magnetic circuit to study the coupled influence of regenerator and magnet dimensions on the device performance. The magnetic circuit is composed of two concentric Halbach cylinders formed by iron and Nd-Fe-B segments and optimized to match the desired ramp magnetic profile. The regenerators are modeled as prisms positioned in the gap between the cylinders and are composed of 3 layers of Gd-Y spheres. By varying simultaneously the external radius of the magnetic circuit and the regenerator height, we obtained an AMR design that can generate a nearly-instantaneous magnetic profile from 0 to 1.2 T, with a magnetic circuit of external radius 120 mm. The proposed design reaches a cooling capacity of 119 W at a regenerator temperature span of 35 K, with a COP of 2.5 and a second-law efficiency of 32.8%.