Research progress of bio-inspired radiative cooling

Run-Heng Yang,Tao Deng,Shun An,Wen Shang

doi:10.7498/aps.71.20211854

Abstract

As a new type of cooling technology, radiative cooling achieves temperature reduction through spectral regulation. Compared with the traditional active cooling technologies such as absorption-based cooling and compression-based cooling, the radiative cooling offers unique advantages, which are of great significance in environmental protection and energy utilization. First of all, the basic principle of radiative cooling and the radiative cooling within the natural biological systems are introduced in this review. The biological systems achieve their regulations of radiative cooling through controlling the materials, microstructures and behaviors in the systems, which also provide inspiration for us to explore new radiative cooling materials and devices. We also summarize the various mechanisms of radiative cooling in the biological systems and the optimization of such cooling structures. The recent research progress of bio-inspired radiative cooling is also presented. At the end, the outlook of the research directions, potential applications, and the material fabrication approaches for bio-inspired radiative cooling are discussed. The radiative cooling materials and devices with high power output and intelligent control should be an important development direction of bio-inspired radiative cooling in the future. With the integration of advanced micro/nano fabrication technology, bio-inspired radiative cooling will have a broader market and much room of applications in the future.

Highlights

Solar radiation absorbed by the terrestrial surfaces; Prad, thermal radiation emitted by the terrestrial surfaces; Patm, atmospheric thermal radiation absorbed by the terrestrial surfaces. (b) AM 1.5 solar spectrum and typical atmospheric window[15]. (c)−(h) Typical organisms and biomaterials with radiative cooling properties: (c) Birds with different near-infrared (NIR) emissivity[16]; (d) comet moth cocoon[17]; (e) butterfly Rapala dioetas and its infrared image[18]; (f) Saharan silver ant[19]; (g) human skin and the structural schematic[20]; (h) wood fiber[21]
(School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China) ( Received 7 October 2021; revised manuscript received 1 December 2021 )

Summary

Low relative NIR

图 1 辐射制冷原理及自然界中对仿生辐射制冷具有启发性的生物和材料 (a) 发生在地球表面的辐射热流示意图 [14]. Psolar, 地球表面对太阳辐射的吸收; Prad, 地球表面发射的热辐射; Patm, 地球表面对大气热辐射的吸收. (b) AM 1.5 太阳光谱和典型的大气透明窗口 [15]. (c)−(h) 典型的具有辐射制冷特性的生物体和生物材料, 依次为具有不同近红外发射特性的鸟类 [16] (c), 彗星蛾蚕茧 [17] (d), 滴燕灰蝶及其红外图像 [18] (e), 撒哈拉沙漠银蚁 [19] (f), 人类皮肤褶皱及其结构示意图 [20] (g), 木材纤维 [21] (h) Fig. 1. Solar radiation absorbed by the terrestrial surfaces; Prad, thermal radiation emitted by the terrestrial surfaces; Patm, atmospheric thermal radiation absorbed by the terrestrial surfaces. (c)−(h) Typical organisms and biomaterials with radiative cooling properties: (c) Birds with different near-infrared (NIR) emissivity[16]; (d) comet moth cocoon[17]; (e) butterfly Rapala dioetas and its infrared image[18]; (f) Saharan silver ant[19]; (g) human skin and the structural schematic[20]; (h) wood fiber[21]. 2020 年, Zhang 等 [26] 探究发现天牛 (图 2(c)) Neocerambyx gigas 的绒毛也具有良好的温度调节作用, 其结构从根部到尖端形成向上的三角形, 可有效地反射可见光并在中红外波段辐射自身能量. Zhang 等 [26] 研究了天牛 Neocerambyx gigas 的辐射制冷机制, 通过光热模拟对其绒毛结构进行了简化和优化, 如图 3(a) 所示, 制备出与生物结构相似的微金字塔阵列聚合物基体, 并在其中随机嵌入陶瓷颗粒, 形成高通量光子仿生制冷薄膜. Choi 等 [32] 研究了家蚕 Bombyx mori 蚕丝的二维蛋白质结构, 通过局部化的强反射与生物分子在红外波段的

Lower layer

Findings

LWIR atmospheric