Early Efforts on Elastocaloric Cooling (2002 to 2014)

Common refrigerants used in vapor compression-based cooling technology, such as R410A, R22, and R134A, are greenhouse gases with warming potential exceeding 1400 times that of CO₂. While cooling helps us survive the hot weather, these refrigerants also make the weather hotter. Thus, there is an urgent need for a cost-effective, highly efficient, and environmentally friendly cooling technology that can break this vicious cycle. Elastocaloric cooling is an emerging technology with the potential to meet this need. Although the elastocaloric effect has been known for several decades, it was only 10 years ago that researchers began to develop it for practical cooling. This article reviews the early work and critical events that led to the development of the first elastocaloric prototype. The major research areas to be reviewed include (1) the search for a low-hysteresis shape memory alloy, (2) investigations into the stress-biased magnetocaloric effect, (3) the demonstration of the elastocaloric effect, and (4) fatigue studies of the elastocaloric effect under compression.