Investigation of resonant dynamics in elastocaloric systems for energy-efficient cooling
Elastocaloric cooling systems, based on the reversible phase transformation of shape memory alloys, offer significant environmental benefits over vapor-compression system by utilizing solid-state refrigerants zero global warming potential and enabling lower energy consumption, thereby contributing to decarbonization efforts. However, the high mechanical work input required for actuation of phase transformation limits the coefficient of performance (COP) and remains a barrier to widespread adoption. This study investigates the dynamic operation of an elastocaloric cooling system under resonant conditions to reduce the actuation work. A single NiTi was cyclically tested to determine the mechanical parameters necessary for resonant frequency and to validate the numerical model. A numerical framework was developed for dynamically operated two NiTi tube bundles operating 180° out-of-phase in reciprocating configuration. Simulation results demonstrate a significant reduction in the input work compared to quasi-static operation, alongside a temperature lift of 32 K and a dynamic amplification factor of 2.9. A sustained cooling performance of 195 W at a temperature lift of 5 K with source and sink temperatures of 20 °C and 25 °C, achieved a maximum COP of 13. Dynamic analysis confirms that resonance-driven operation minimizes energy losses due to mechanical damping, highlighting the potential of resonance tuning as an effective strategy for improving the energy efficiency and viability of elastocaloric cooling technologies.