INFLUENCE OF MATERIALS AGE ON THEIR THERMAL PERFORMANCE THE CASE OF TEXTURED COATINGS FOR FACADES

Abstract

The results presented in this article are framed within a research project that studies solutions for urban spaces (morphology, materials, construction techniques, etc.) in order to mitigate the impact of Urban Heat Islands. The cold materials present in the urban envelope help to reduce energy demand for cooling in air conditioned buildings and improve the comfort of open spaces, contributing to environmental sustainability through the rational use of energy. Solar reflectance of the building envelope tends to change with time due to outdoors and dirt accumulation. Therefore, for a period of two years it was measured thermo-physical behavior of 80 textured coatings for facades on two compositions: acrylic (SIP) and cement (CW), with colors, textures and finishes spread locally to the vertical resolution of the urban envelopes. The variation of the thermal behavior with erosion was evaluated by modifying the Solar Reflectance indicator over time. Solar Reflectance Index -SRI- is defined as the determination of the solar reflectance, thermal emitancia and the relative temperature of the surfaces with respect to a reference temperature of a black and white pattern. This index allows weighting the effect of aging on the thermal behavior of the materials evaluated. The results show that 35% of acrylic coatings decrease their ability to mitigate the effects of heat island, while 98% of the cementitious maintained or increased their capacity of mitigating.