Electrocaloric cooling system utilizing latent heat transfer for high power density

Electrocalorics (EC) is potentially more efficient than refrigeration and heat pumps based on compressors and does not need detrimental fluids. Current EC-prototypes use solid-state contact or forced convection with liquids to transfer the heat generated from the EC-material, which inhibits high cycle frequencies and thus limits power density. Here we present a heatpipe system solution, where the heat transfer is realized through condensation and evaporation of ethanol as a heat transfer fluid. Our prototype with lead scandium tantalate (PST) EC-material working at 5 Hz shows a specific cooling power of 1.5 W g−1. This is one order of magnitude more than previously reported for ceramic EC-prototypes. Overcoming the limits of slow heat transfer is essential to reach high specific cooling powers enabling a future commercial success of the technology. Julius Metzdorf and colleagues present a heatpipe system that combines solid-state electrocaloric material with condensation and evaporation of ethanol fluid. The results demonstrate an enhanced cooling power density, which is one order of magnitude higher than that of traditional ceramic electrocaloric systems.