近日，上海交通大学机械与动力工程学院的钱小石及其研究团队取得一项新进展。经过不懈努力，他们研制出高能效自振荡聚合物制冷机。相关研究成果已于2024年5月8日在国际权威学术期刊《自然》上发表。

该研究团队报道了一种利用聚合铁电体提供的电热机械协同作用的电热薄膜设备。在一次交流电激励下，该设备由工作体自身进行热循环和机械循环，形成无外部驱动、自循环的软制冷机。该原型机的直接测量冷却功率密度为6.5Wg^-1，在零温度范围下的峰值COP超过58。该设备仅为30 μm厚的聚合物薄膜，在开放环境下，在4K温度范围下实现了接近24的COP(热力学效率32%)。相较于被动冷却，薄膜制冷机能够迅速为电子芯片带来高达17.5K的额外温度降幅。而软聚合物制冷机则拥有出色的感知、驱动和热量泵送能力，从而实现自动的局部热管理。

据悉，介电材料中同时存在着电热和电致伸缩效应。通过结合电热制冷所产生的两种效果，人们可以实现轻量化、紧凑的局部热管理。然而，尽管有数值模型和示意图作为参考，现有的电热制冷技术仍需要依赖外部附件来驱动工作体，因此导致设备级冷却功率密度和性能系数(COP)较低。

附：英文原文

Title: Self-oscillating polymeric refrigerator with high energy efficiency

Author: Han, Donglin, Zhang, Yingjing, Huang, Cenling, Zheng, Shanyu, Wu, Dongyuan, Li, Qiang, Du, Feihong, Duan, Hongxiao, Chen, Weilin, Shi, Junye, Chen, Jiangping, Liu, Gang, Chen, Xin, Qian, Xiaoshi

Issue&Volume: 2024-05-08

Abstract: Electrocaloric and electrostrictive effects concurrently exist in dielectric materials. Combining these two effects could achieve the lightweight, compact localized thermal management that is promised by electrocaloric refrigeration. Despite a handful of numerical models and schematic presentations, current electrocaloric refrigerators still rely on external accessories to drive the working bodies and hence result in a low device-level cooling power density and coefficient of performance (COP). Here we report an electrocaloric thin-film device that uses the electro-thermomechanical synergy provided by polymeric ferroelectrics. Under one-time a.c. electric stimulation, the device is thermally and mechanically cycled by the working body itself, resulting in an external-driver-free, self-cycling, soft refrigerator. The prototype offers a directly measured cooling power density of 6.5Wg^-1 and a peak COP exceeding 58 under a zero temperature span. Being merely a 30-μm-thick polymer film, the device achieved a COP close to 24 under a 4K temperature span in an open ambient environment (32% thermodynamic efficiency). Compared with passive cooling, the thin-film refrigerator could immediately induce an additional 17.5K temperature drop against an electronic chip. The soft, polymeric refrigerator can sense, actuate and pump heat to provide automatic localized thermal management.

DOI: 10.1038/s41586-024-07375-3

Source: https://www.nature.com/articles/s41586-024-07375-3