Optimization of heat transfer mechanisms in elastocaloric cooling systems

Abstract

Elastocaloric cooling has swiftly emerged as a promising cutting-edge solid-state cooling technology, offering environmentally friendly and efficient alternatives to conventional cooling systems. To enhance the performance of the elastocaloric cooling system, the primary strategy involves increasing the operational frequency and specific heat transfer area. This study investigates the heat transfer mechanisms within the elastocaloric regenerator, focusing on the time scales associated with different heat transfer modes, namely conduction and convection. A novel non-dimensional design variable, thermal utilization ratio (Z*), is introduced to evaluate the performance of elastocaloric systems. Using a numerical model, the cooling capacity and temperature lift of a tubular NiTi elastocaloric cooling system were optimized with respect to Z*. Additionally, the effect of the optimized Z* parameter for the elastocaloric system was studied by simulating different materials and geometries. This analysis provided a relation between the optimum value of Z* for different elastocaloric materials and geometries, providing critical insight into the selection of design parameters for maximizing the performance of elastocaloric cooling systems.