Experimental study of optical and cooling performances of CuO and TiO2 near-infrared reflective blending coatings

摘要

Reflective coating can be used as an effective technology to cool the pavements in cities and some special regions, e.g., permafrost regions. Given few reflective coatings are single-pigment dispersion, it is necessary to investigate the optical and thermal properties of coatings consisting of more than one pigments. Here we first take three types of particles, i.e., CuO microparticles (MPs), CuO nanoparticles (NPs) and TiO2 nanoparticles (NPs), as pigments to make 12 types of epoxy-based blending coatings, then study their spectral reflectances and finally evaluate the cooling performances of eight selected coatings. Result shows that all the CuO and TiO2 blending coatings are near-infrared reflective coatings, more specifically: (1) For a given total mass percentage of CuO and TiO2 particles, with the increase of TiO2 NPs, the spectral reflectance of the TiO2 NPs and CuO NPs blending coating increases slightly, while that of TiO2 NPs and CuO MPs increases largely; (2) For a given CuO particles mass percentage, the spectral reflectance of the CuO NPs and TiO2 NPs blending coating is higher than that of the CuO MPs and TiO2 NPs blending coating when the TiO2 NPs mass percentage is lower than 15.88%; the situation will be reversed when the TiO2 NPs mass percentage is equal or higher than 15.88%; (3) the cooling performances of these selected near-infrared coatings are found no matter under the summer or autumn meteorological condition. This study can provide insights and references for fabricating the near-infrared reflective blending coatings, thereby reducing the undesired pavement absorbed energy.