Modeling the Steady-State Performance of SMA-based Elastocaloric Refrigeration Cycle

In this work, we utilize COMSOL Multiphysics to model the heat flow into and out of a Nickel-Titanium (NiTi) Shape Memory Alloy (SMA) as it bends around a rotating copper disk, which acts as a thermal mass for heating or cooling. The model is verified using a novel experimental system capable of capturing the thermal gradient through the disk. We then interrogate the impacts of the wire’s cross-sectional geometry, contact thermal resistance at the disk junction, rotational speed of the disk, and the disk’s radius of curvature on the cycle’s coefficient of performance (COP). Our results suggest that this modeling technique can accurately capture the endothermic and exothermic reactions associated with the phase change. We therefore provide a useful tool for developing and optimizing next-generation passive cooling and heating systems.