A multistage elastocaloric refrigerator and heat pump with 28 K temperature span

Elastocaloric refrigerators are a promising alternative to the vapor compression cycle because they do not require refrigerants with high global warming potential. However, these coolers have yet to achieve temperatures low enough to - for example - be used as standard household refrigerators. We built one-stage, two-stage, and three-stage elastocaloric cooling systems to determine if staging of the elastocaloric effect could significantly expand temperature span. Our three-stage system achieved 1.5 times the maximum temperature span of our single-stage system, and produced the highest temperature span of any elastocaloric device to-date at 28.3 degrees C, where previously the record was 19.9 degrees C. Interestingly, we found that multistage systems can achieve equivalent temperature spans but at higher coefficients of performance compared to similarly-constructed single-stage systems.