Elastocaloric heat pumping using a shape memory alloy foil device

This paper explores, develops and demonstrates a miniature heat pump based on the elastocaloric effect in shape memory alloys (SMAs). The active material is a Ti
_50.5
Ni
_49.1
Fe
_0.4
foil of 30 μm thickness showing a maximum temperature change during pseudoelastic loading/unloading up to +20/-16 K. This effect is implemented in a heat pump design consisting of SMA bridge, heat source and sink. First-of-its-kind demonstrators reveal a temperature difference between source and sink of about 7 K after 100 s for a ratio of heat capacities of SMA bridge and heat source of 1:85. The coefficient of performance (COP) of the device for cooling is 2.8 whereas the theoretical COP of the material is 10.5.