Cooling efficiency and losses in electrocaloric materials

A figure of merit for assessing the cooling efficiency of electrocaloric (EC) materials is defined, where the caloric properties are taken into account jointly with the material's losses. Using a specifically developed measurement setup, based on flexible thermistances, the caloric effect and the losses are directly measured on P(VDF-TrFE-CFE) electrocaloric polymer films. The data are used, jointly with our figure of merit, to extrapolate the cooling efficiency to be expected, under actual working conditions, from the studied EC material. Dielectric losses emerge as a major limiting factor for achieving the needed cooling performance. This finding shows that, beside the research for huge caloric response, material loss reduction has to be considered a key objective for researching an optimal EC refrigerant for cooling applications. Eventually, some strategies toward loss reduction are outlined.

Automated summary

A figure of merit is defined to assess the cooling efficiency of electrocaloric materials by considering both caloric properties and losses. A measurement setup based on flexible thermistances is used to directly measure the caloric effect and losses of P(VDF-TrFE-CFE) electrocaloric polymer films. The data, along with the figure of merit, are used to extrapolate the expected cooling efficiency of the studied EC material under actual working conditions. Dielectric losses are found to be a major limiting factor, and reducing material losses is identified as a key objective for optimizing EC refrigerants for cooling applications. Strategies towards loss reduction are outlined.