An electrocaloric element for a heat transfer system includes an electrocaloric material of a copolymer of (i) vinylidene fluoride, and (ii) an addition polymerization monomer that is larger than vinylidene fluoride and includes a substituent more electronegative than chlorine. Electrodes are disposed on opposite surfaces of the electrocaloric material, and an electric power source is configured to provide voltage to the electrodes. The system also includes a first thermal flow path between the electrocaloric material and a heat sink, and a second thermal flow path between the electrocaloric material and a heat source.