Stacked porous NiTi structure with low cost and ultrahigh fatigue life for elastocaloric cooling

Elastocaloric cooling (eC) uses shape memory alloys (SMAs) as energy-efficient, eco-friendly refrigerants. However, cost-effectively fabricating SMAs into fatigue-resistant, heat transfer–enhanced structures remains a key obstacle to commercialization of the eC technology. We introduce a “stamping and stacking” (S-S) method for producing porous, fatigue-resistant SMA structures. Honeycomb-like chips are stamped from nitinol (NiTi) thin sheets and then stacked into a layered tubular structure to increase heat exchange surface and at the same time avoid buckling and splitting failures encountered in existing SMA structures. The stacked structure endures >10 8 compression cycles and can deliver high specific cooling power of 3850 watts per kilogram. Our S-S method reduces fabrication costs by one order of magnitude compared with existing approaches, enabling mass production of eC refrigerant structures for commercial deployment.