International Journal of Energy Research, Vol.44, No.7, 5343-5359, 2020
Device-level thermodynamic model for an electrocaloric cooler
An electrocaloric (EC) cooling device model is proposed to study the influence of material properties, operating conditions, and device design on the coefficient of performance (COP). Because the EC temperature change cannot be predicted by ferroelectric material models, a Gaussian-fit model is proposed that achieves accurate predictions for a range of materials. The COP is calculated by considering the heat transfer and work in a thermodynamic cycle that is integrated with the material model. The device model is based on the experiments of Ma et al (Science. 2017;357:1130) and includes contact and convective thermal resistances, the work to apply the electric fields, and dielectric loss heating. A copolymer and a terpolymer are analyzed. The predicted heat flux is in good agreement with the experimental data while the predicted COP is lower. This difference is attributed to an over-prediction of the work because experimental hysteresis loop data are not available. Parametric analysis reveals that: (a) the terpolymer performance is stable over a wide range of operating temperatures, while good performance of the copolymer is limited to near its Curie temperature, and (b) small contact thermal resistances allow for high-frequency operation and a large heat flux.