Efeitos do uso de telhados vegetados em ilhas de calor urbanas com simulação pelo software ENVI-Met

Abstract

Urbanization, by modification of the natural landscape, alters the aerodynamic and radiative properties of the surface, in the thermal properties of the substrate and in the hydraulic properties of the surface and the soil, modifying thus the thermal and radiometric properties of the urban atmosphere. The effect of vegetation on urban climate is already investigated some time ago and its benefits can be observed not only in the vegetated area, but also in its surroundings. A possible solution for the incorporation of vegetation within the urban context is the transformation of traditional roofs of buildings in green roofs. The aim of this study is to evaluate green roof’s effects in a urban heat island with simulation at ENVI-Met software in the city of Cuiabá, MT. The development methodology of this study involves two main phases: Survey (microclimatic and spatial) and Simulation. The microclimatic survey was carried out through a fixed micrometeorological station and a mobile transect, in the periods of the january to march of 2013 (hot humid ) and the july to september of 2013 (hot dry). The spatial survey was conducted by aerial photogrammetry in the photogrammetric station digital E-Photo, complemented by in situ observations. The simulation was developed in the software ENVI-Met, for the two periods of the year, in four different scenarios, being a real scenario, with the incorporation of vegetated roof in 10% of roofs, another 50% and another with 100%. In general, the results confirmed the validity of the model ENVI-Met as a tool of microclimate forecast for the city of Cuiabá, MT. All scenarios cause interference in local microclimate, which validates the vegetated roof as a strategy for minimizing the effects of the urban heat island, mainly in the region above the rooftops and the level of backyards. The most significant results were obtained in the scenario with 100% of green roof, assuming decreasing of air temperature of up to 1.56 °C and an increase in relative humidity of up to 4.80%. The scenarios with green roof do not interfere on thermal comfort at ground level. These results highlight the importance and benefits of green roof as a passive strategy of both thermal conditioning of buildings as urban space, reinforcing the importance of bioclimatic urban planning to ensure the quality of life of its inhabitants.