ABSORTÂNCIA SOLAR E TEMPERATURAS SUPERFICIAIS DE TELHAS CERÂMICAS NATURAIS E RESINADAS

Abstract

Materials from the built envelope are important for the thermal performance of buildings, since the amount of heat absorbed by the surface will be transmitted to the indoor environment. Therefore, the solar absorptance is an important thermo-physical characteristic of the surface, that must be known, studied and used in order to provide better thermal comfort conditions to the users, considering the climate in which the building is located. In this context, this article aims to evaluate the thermal performance of ceramic tiles in relation to solar absorptance and their surface temperatures, considering the differences between natural and resin coats on solar absorptance values. For this, 21 ceramic tiles were selected and field and laboratory measurements were performed: surface temperatures with infrared thermometer and solar absorptance using a spectrophotometer with integrating sphere. With the analysis of the collected data, it was observed initially that tiles with natural coat have, in general, lower solar absorptance than tiles with resin coat, therefore the resin applied interferes in these values. Comparing data of surface temperature and solar absorptance, it was observed that tiles with higher variation between initial and final temperatures are those with higher solar absorptance. The results also indicated that both tile roughness and porosity interfere directly on the final values of surface absorptance, enhancing that the solar absorptance is a characteristic of the materials surface.