Kubelka-Munk revised theory for high solar reflectance and high long-wave emissivity coatings designing

Abstract

The Kubelka-Munk revised theory was adopted to derive the mix design theory of high solar reflectance and high emissivity coatings. When the concentration of each colorant is within 20%, and the width of the coating is more than 200 μm, each colorant has enough covering power in visible and near-infrared spectral range. It can be assumed that the addition of colorants in coatings can only change the solar spectral absorption ratio rather than solar spectral scattering coefficient. The spectral scattering coefficient of coatings tends to a constant. The spectral absorption-scattering property of each colorant can be characterized through one parameter. The spectral absorption-scattering coefficient of coatings can be calculated with the multivariate linear relationship of each pigment. Moreover, the results can be expanded for high solar reflectivity and high long-wave emissivity coating preparation. The accuracy of Kubelka-Munk revised theory has been tested and verified through comparison between the calculated value and tested value of coating reflectance.