Technical Summary

Elastocaloric cooling and heating involves causing shape memory alloys (commonly nitinol (NiTi), an alloy of nickel and titanium) to undergo stress-induced phase changes and, correspondingly, to release or absorb heat. The Department of Energy and others have identified elastocaloric cooling as the most-promising alternative to vapor-compression refrigeration technology. The obstacle to commercialization has been the large amount of force required to cause the requisite phase changes.

Barrow Green’s innovation is to reduce the amount of force required to cause the requisite phase changes through bending (rather than stretching or compressing) the shape memory alloys by driving such shape memory alloys in a reciprocating loop using commercial off-the-shelf motors. Such a reduction in force achieves energy efficiency significantly greater than that of conventional vapor compression cooling. In addition, such a reduction in force reduces the size of the actuators required to cause the requisite phase changes, making smaller units possible.