Superelastic Porous Structures for Efficient Elastocaloric Cooling

Cooling, refrigeration and air-conditioning are crucial for our modern society. In the last decade, the global demands for cooling are growing exponentially. The standard refrigeration technology, based on vapour compression, is old, inefficient and environmentally harmful. In the SUPERCOOL project we will exploit the potential of elastocaloric cooling, probably the most promising solid-state refrigeration technology, which utilizes the latent heat associated with the martensitic transformation in superelastic shape-memory alloys. We have already demonstrated a novel concept of utilizing the elastocaloric effect (eCE) by introducing a superelastic porous structure in an elastocaloric regenerative thermodynamic cycle. Our preliminary results, recently published in Nature Energy, show the tremendous potential of such a system. However, two fundamental challenges remain. First, we need to create a geometry of the superelastic porous structure (elastocaloric regenerator) to ensure sufficient fatigue life, a large eCE and rapid heat transfer. Second, we must have a driver mechanism that can effectively utilize the work released during the unloading of the elastocaloric regenerator. To succeed I am proposing a unique approach to design advanced elastocaloric regenerators with complex structures together with a driver mechanism with the force-recovery principle. We will employ a systematic characterization and bottom-up linking of all three crucial aspects of the elastocaloric regenerator, i.e., the thermo-hydraulic properties, the stability and the structural fatigue, together with a new solution for force recovery in effective drivers. Based on these theoretical, numerical and experimental results we will combine both key elements of our novel elastocaloric concept into a prototype device, which could be the first major breakthrough in cooling technologies for 100 years, providing greater efficiency and reduced levels of pollution, by applying a solid-state refrigerant.