Desempenho térmico de coberturas vegetais em edificações na cidade de São Carlos-SP

Abstract

Planted roofs, known as green roofs as well, can positively contribute to the improvement of buildings thermal performance and cities climate. The advantages of the planted roofs have been object of study of several researchers along different countries. However, some quantitative data on this subject are still needed in the context of tropical climate. The aim of this work is to evaluate the thermal performance of a planted roof and how it influences the thermal protection of the building, in accordance with São Carlos climatic conditions. The investigations were implemented for not only winter, but summer too. During both periods, air relative humidity, surface and air temperature measurements were taken at the indoor and the outdoor environment of the building prototype. Moreover, a comparison between a bare roof and of a green roof was made, using the same building prototype. The outdoor surface temperature for the bare roof and the leaves, which cover the green roof, was estimated through a Jardim 1.0 computational program. Data of global solar irradiance and wind velocity, necessary to estimate the outdoor surface temperatures, were achieved through a weather station. The analysis were ordered according to the thermal performances of the roofs in each one of the situations, separately, and between one and other situation. By field measurements, during the winter and the summer, smaller thermal amplitudes were noticed for the green roof. In the winter, the green roof presented medium thermal amplitude 70% smaller than the bare roof. During the summer, the amount of heat coming into the building prototype was reduced by the green roof. These and other results indicate the major green roof capacity of reducing daily temperature variations and thermal ranges. It has been confirmed that planted roofs effectively contribute to improve the thermal benefits being both, cost and energy effective, for the buildings and their surrounding environment.