Scale law on energy efficiency of electrocaloric materials

Caloric materials are suggested as energy-efficient refrigerants for future cooling devices. They could replace the greenhouse gases used for decades in our air conditioners, fridges, and heat pumps. Among the four types of caloric materials (electro, baro, elasto, magneto caloric), electrocaloric materials are more promising as applying large electric fields is much simpler and cheaper than the other fields. The research in the last years has been focused on looking for electrocaloric materials with high thermal responses. However, the energy efficiency crucial for future replacement of the vapor compression technology has been overlooked. The intrinsic efficiency of electrocaloric has been barely studied. In the present dissertation, we will study the efficiency of EC materials defined as materials efficiency. It is the ratio of the reversible electrocaloric heat to the reversible electrical work required to drive this heat. In this work, we will study the materials efficiency of the benchmark lead scandium tantalate in different shapes (bulk ceramic and multilayer capacitors). A comparison to other caloric materials is presented in this dissertation. Our work gives more insights on the figure merit of materials efficiency to further improve the efficiency of our devices.