Pulse Shape Effects in Electrocaloric Cooling

We report on the solution of the heat equation, which describes the electrocaloric effect in a ferroelectric layer. The dependence of the heat flux at the layer interface and the thermodynamic efficiency on the shape and frequency of the applied pulse is investigated. According to the calculations, the dependence of the efficiency on the frequency for a rectangular and sinusoidal pulse has a markedly different character. The maximum efficiency at 0.74 is achieved by a sinusoidal impulse at a frequency of 77.6 mHz. The new approach allows for better optimization of the cooling system. To model a heat switch, it is proposed to use a change in the Biot number over time. Theoretical calculations are compared with experimental results for a 0.5-mm-thick barium titanate plate. The maximum heat flux that can be created for a given plate under an electric field of 2 MV/m with an ideal heat switch turned out to be equal 120.72 W/m².