Designing the structural and operational parameters of a single long NiTi tube compressive elastocaloric cooler by lumped analysis

Elastocaloric cooling is a promising alternative for vapor-compression technology due to its high specific cooling power, long fatigue life, zero global warming substance emission, and relatively low cost. A convenient, efficient, and accurate modeling for elastocaloric cooling cycles is of great significance for the designation and optimization of elastocaloric solid-state coolers. In this article, we developed a heat transfer model using the lumped analysis method for performance evaluation of elastocaloric coolers. The analytical solution for the coupled volume-averaged temperatures of the NiTi shape memory alloy and heat transfer fluid during an elastocaloric cooling cycle was obtained, which was used to calculate the elastocaloric cooling performance, including the temperature span/lift, specific cooling power, and coefficient of performance. The lumped heat transfer model was validated by the experimental data of temperature–time relationship and specific cooling power for our single long NiTi tube compressive elastocaloric cooler. We analyzed the effects of heat transfer fluid properties, structural parameters, and operation parameters on the cooling performance of our elastocaloric cooler using the lumped heat transfer model. According to current knowledge and experience, we analyzed the coupling among fundamental factors affecting the elastocaloric cooling performance and established a flow chart for the designation of elastocaloric coolers. The results in this article can not only be used in the modeling of elastocaloric coolers but also have the potential to be applied in other caloric cooling technologies.