A double-layer radiative cooling coating that utilizes the refractive index difference between layers to achieve extremely high solar reflectivity  

作　　者：WANG FuQiang LI ChunZhe YANG ZhenNing XIE WeiXin LI Xiang XU ZengHui YAN YuYing CHENG ZiMing 

机构地区：[1]School of Energy Science and Engineering,Harbin Institute of Technology,Harbin 150001,China [2]School of New Energy,Harbin Institute of Technology at Weihai,Weihai 264209,China [3]China Construction Eco-Environmental Protection Technology Co.,Ltd.,Suzhou 215123,China [4]Faculty of Engineering,University of Nottingham,Nottingham NG72RD,UK

出　　处：《Science China(Technological Sciences)》2024年第10期3182-3189,共8页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.52306078 and 52211530089);Taishan Scholars of Shandong Province(Grant No.tsqn201812105);the Natural Science Foundation of Shandong Province(Grant No.ZR2023QE141);the Royal Society(Grant No.IEC\NSFC\211210)。

摘　　要：Passive daytime radiative cooling(PDRC)technology has great potential in reducing cooling energy consumption.In order to further improve the spectral performance of PDRC coatings,current researchers mostly focus on the selection and size design of functional particles,while ignoring the optical properties enhancement effect caused by the interlayer binder.In this study,based on the principle that the refractive index difference between layers enhanced the backscattering performance of the solar spectrum,we proposed and manufactured a double-layer PDRC coating with polyvinylidene difluoride(PVDF)as the filmforming material in the upper layer and polydimethylsiloxane(PDMS)as the film-forming material in the lower layer,both filled with Al_(2)O_(3) and SiO_(2) particles.The double-layer PDRC coating exhibited excellent spectral performance that a high solar reflectivity of 98%and an emissivity of 0.95 at the“atmospheric window”band.In comparison,the solar spectrum reflectivity of the single-layer PDRC coatings based on PVDF and PDMS of the same thickness was 95%and 94.7%,respectively.Outdoor tests showed that the PDRC coating achieved a temperature decrease of up to 7.1℃ under direct sunlight at noon time.In addition,the PDRC coating had excellent weather resistance,water resistance,and other basic properties.This article opens up a new idea and provides methodological guidance for the design of double-layer PDRC coatings.

关 键 词：double-layer radiative cooling coating spectral modulation interlayer refractive index solar energy radiative transfer 

分 类 号：TB306[一般工业技术—材料科学与工程]