Dynamic-mesh modeling of low-cost polymer microchannel regenerators for elastocaloric cooling

Elastocaloric cooling is a low-global-warming-potential alternative to vapor-compression refrigeration. However, the high cost of shape memory alloys and high-force actuators limits its large-scale deployment. Polymer-based materials such as natural rubber (NR) and thermoplastic polyurethanes (TPU) provide cost-effective alternatives but undergo large operational strains (up to 600%), which challenge conventional regenerator designs and numerical modeling approaches. In this study, a transient one-dimensional numerical model with a dynamic-mesh formulation is developed to capture coordinate transformations and coupled thermo-hydraulic behavior in large-deformation elastocaloric regenerators. Four microchannel geometries (parallel plate, square, triangular, and circular) are evaluated. Using NR as the working material, the triangular configuration achieves the highest specific cooling power (SCP) due to enhanced heat transfer and reduced viscous dissipation. Parametric optimization identifies an optimal pore size of ∼400 μm at 50% porosity. Replacing NR with high elastocaloric response TPU further improves cooling performance. At an operating
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frequency of 1 Hz, the optimized triangular TPU regenerator is numerically predicted an SCP of 17.4 Wg$^{−1}$, which is three times higher than that of NR. Polymer-based regenerators offer an active-material cost per unit cooling power of 4.3 − 5.0 × 10$^{−4}$/W, highlighting the potential for cost-effective elastocaloric cooling. This work provides quantitative design guidelines for scalable polymer-based elastocaloric cooling systems.