Compact Cooling Devices Based on Giant Electrocaloric Effect Dielectrics

The electrocaloric effect (ECE) refers to the change in temperature and/or entropy of a dielectric material due to the electric field induced change of dipolar states. Giant ECE is discovered in P(VDF-TrFE) ferroelectric copolymers near ferroelectric-paraelectric (F-P) transition temperature which is normally much higher than room temperature. This paper presents the two defect-inducing methods to lower and broaden working temperature range of P(VDF-TrFE) based copolymers for ECE, and thus make it preferable for practical cooling device. Giant ECE is experimentally demonstrated in large temperature range (0–55°C). In addition, an electrocaloric oscillatory refrigerator (ECOR) was proposed and simulated by finite volume method and its high performance was theoretically demonstrated. Temperature gradient larger than 30 °C can be maintained across the two sides of a 1 cm device. For ΔT = 20 °C cooling condition, a high cooling power (5.4 W/cm²) and significantly higher coefficient of performance (COP) can be achieved (50% of Carnot efficiency).