A Simulative Evaluation of Triply Periodic Minimal Surface Structures in the Context of Elastocaloric Applications

Elastocaloric technology is currently the most promising alternative air conditioning technology, in terms of environmental friendliness and efficiency. To optimize an elastocaloric machine in its entity, it is essential to research and improve all components, from the material to efficient load concepts. This work is dedicated to the evaluation of triply periodic minimal surface (TPMS) structures for use as heating/cooling element within an elastocaloric machine. TPMS structures have promising properties such as a high surface/volume ratio, which offers great potential for the exchange of generated thermal energy with the environment. They consist of continuous curved surfaces without notches, which act as nucleation points for fatigue cracks under cyclic loading, commonly found in continuous operating cooling devices. The structures Gyroid, Diamond, Schwarz, and FischerKochS are compared by simulating compression tests. The elastocaloric efficiency, defined as the quotient of generated thermal energy and invested mechanical work and the heat exchange potential, are used as evaluation criteria. To illustrate the improvement that can be achieved by using TPMS structures instead of conventional geometries, a tube is used as a comparative geometry. The observed deformation mechanisms are correlated with the results of a geometric analysis to determine optimization strategies for the investigated structures.