Giant temperature span in electrocaloric regenerator

Abstract

Cooling devices based on caloric materials have emerged as promising candidates to become the next generation of coolers. Several electrocaloric (EC) heat exchangers have been proposed that use different mechanisms and working principles. However, a prototype that demonstrates a competitive temperature span has been missing. We developed a parallel-plate active EC regenerator based on lead scandium tantalate multilayer capacitors. After optimizing the structural design by using finite element modeling for guidance and to considerably improve insulation, we measured a maximum temperature span of 13.0 kelvin. This temperature span breaks a crucial barrier and confirms that EC materials are promising candidates for cooling applications.

Giant electrocaloric materials energy efficiency in highly ordered lead scandium tantalate

“…A more suitable use is to integrate this material into a regenerator. The interest of such a device is to build a gradient of temperature larger than Δ T adiab by running a specific thermodynamic cycle 4 . To do so, the positive Δ T adiab must be triggered at a temperature higher than when the negative Δ T adiab is triggered in this cycle.…”

“…Other functional examples are given in Supplementary Note 14 . Moreover, we checked that bulk PST can be run in a regenerator by simulating it with a proven finite element model, detailed in 4 (Supplementary Fig. 21 ).…”

“…Lately, Nair et al 20 measured a larger ∆ T adiab of 5.5 K in PST Multi-Layer Capacitors (MLCs) when driven supercritically at 290 kV cm −1 . In addition, we showed that an EC prototype built using 128 PST MLCs can reach a giant temperature span of 13 K 4 . These previous works demonstrate that PST remains one of the best candidates for EC cooling.…”

“…Looking for an alternative to the almost exclusively used vapor compression system is a crucial technological challenge as one needs to suppress the use of greenhouse gases and improve energy efficiency as much as possible 2 , 3 . Recent findings have demonstrated that electrocaloric (EC) devices represent a more and more credible alternative 4 – 6 .…”

“…Lead Scandium Tantalate Pb(Sc 1/2 Ta 1/2 )O 3 , short form PST 11 – 16 is one of the most promising EC materials, already utilized to build EC heat pumps 4 , 5 , 17 – 19 . It exhibits a first-order ferroelectric to paraelectric (PE) phase transition near room temperature which makes it attractive for air conditioning.…”