Potential uses of portable spectrometer for solar reflectance determination of ceramic tiles for building roofs

Abstract

In countries like Brazil with intense and large availability of solar radiation all year long, solar heat gains by the building envelope are the main responsible for its thermal and energy performance, and for consequence the user's thermal comfort. The solar reflectance is the main factor with large influence on the envelope solar heat gains, a physical property associated to surface color and roughness and the materials chemical composition. The solar reflectance is defined as the ration between the solar energy reflected by the surface and the total energy incident. At the present time, there are three standardized methods for measuring solar reflectance, but they indicate the use of high cost equipment, not accessible to all researchers and professionals. As a consequence, it is usual the adoption of general and not accurate values of solar reflectance based only on the color of materials, published in tables from standards and technical books. In this context, this research project addresses the evaluation of potential uses of a low cost portable spectrometer for solar reflectance determination of ceramic tiles, and present recommendations for accurate solar reflectance measurements with this equipment. Research initiated by the advisor of the candidate already indicates this method is possible, as well as other recent researches indicate. Otherwise, results from these researches point out the need of improvement in the measurement method, once they were adopted only for coatings reflectance measurements and not for ceramic tiles, which have different surface characteristics. This research will include field and laboratory experiments, with reflectance and surface temperature measurements, as well as data analysis and the improvement of the methodology. The research project it will be part of a larger research to be developed by the advisor of the candidate.