Development of compression-based elastocaloric cooling systems based on superelastic shape memory alloys

Elastocaloric/thermoelastic cooling based on superelastic shape memory alloys uses the large latent heat associated with the martensitic transformation to pump heat. Elastocaloric cooling has been recognized by DOE as one of the most promising alternative cooling technologies. We have been developing prototypes of elastocaloric cooling systems using superelastic NiTi. Our effort started with tension-based coolers using NiTi wires. Because of the fatigue issue associated with wires, we have since been focusing on compression-based devices. Key features of our cooling devices include tube-bundle-based heat exchangers and a work-recovery system which is necessary for high-efficiency operation of the systems. Our recent effort is focused on implementing active regeneration schemes. We have recently succeeded in demonstrating a 50 W water chiller in a double cascade configuration with temperature lift of 21 K across the regenerator. I will also discuss our effort in development of new materials for elastocaloric cooling. This work is carried out in collaboration with David Catalini, Nehemiah Emaikwu, Jan Muehlbauer, Yunho Hwang, Reinhard Radermacher, Jun Cui, and Huilong Hou. Our work is funded by DOE EERE BTO.