Avaliação do desempenho térmico de telhados verdes em Aracaju-SE através de simulação computacional

Abstract

The natural vegetation cover of the soil was suppressed to give space to new buildings because of an increase in the urbanization of the cities. These buildings, especially those in tropical regions, are subjected to elevated solar radiation, leading to higher temperatures indoors. In the recent years, the urge in environmental awareness fueled the search for less environmentally harmful solutions in Civil Construction. One way to improve the sustainable character in this field is through the installation of green roofs in buildings. Besides being less environmentally impactful, the installation of green roofs has other advantages, such as improving the internal microclimate of the building. Keeping that in mind, the overall goal of this study was to compare the thermal performance of three types of green roof (intensive green roof, unglazed ceramic roof tile, and extensive green roof) through computational simulation subjected to the weather conditions of the city of Aracaju, in the state of Sergipe (Brazil). The influence of green roofs on a classroom was analyzed in a prototype for calibration purposes. First, computational models of the prototype and the classroom have been created in the software Sketchup™, through the plug-in Euclid™. Next, the prototype model was calibrated through comparisons between the simulation results and experimentally measured ones. After the calibration, six thermal simulations of the model were performed changing the following variables: type of roof (unglazed ceramic roof tile, extensive green roof and intensive green roof) and the boundary condition on the external side of the walls (adiabatic vs diathermal walls). Subsequently, thermal simulations of the classroom model were performed changing its roof cover (unglazed ceramic roof tile, extensive green roof and intensive green roof) in each simulation. The simulations covered all the hours in the year and the analysis of the results involved two weeks: one representing a dry season and one representing a rainy season. In the simulations with the prototype, the use of the green roof led to internal temperature reductions of the building up to 0.89 °C (diathermal wall) and up to 3.65 °C (adiabatic wall). In the classroom simulations, the use of the green roof led to internal temperature reductions up to 1.15 °C. Overall, the thermal performance of the intensive green roof and extensive green roof were superior to that of the unglazed ceramic roof tile for both the prototype and the classroom, especially for the dry season. Therefore, this work adds value to professionals aiming to work with green roofs and to acquire a deeper knowledge about the enhancement in thermal performance promoted by them.