Índice de sombreamento da wisteria floribunda usada em um sistema de fachada verde

Abstract

Green facades are alternative solutions that promote the shading of parts or the entirety of a building through the use of specific plants suitable for such use. Green facades can increase thermal and acoustic insulation, as well as contribute to the mitigation of urban heat islands. In this sense, the use of green facades is an important strategy to reduce the energy demands of refrigeration systems, improving the thermal and energy performance of buildings, in addition to contributing to increase urban resilience in the face of global climate change. This course conclusion work aimed to evaluate the shading index (SI) of a green facade installed on the west side of a popular experimental building vegetated with Wisteria floribunda. Through a monthly photographic monitoring over a year, the SI and the consequent interferences in the surface temperature of the external face of the wall influenced by the vegetation were evaluated. The results show a maximum IS of 99.71% during the summer, when the plant presents greater vegetative development. As expected, the SI during the autumn and winter months reduced significantly, to values close to zero. From the analysis of the thermal data, it was observed that the maximum difference between the air temperature and the temperature of the external facade occurred in the summer, when for the representative day of maximum and minimum temperature recorded an amplitude of 15 °C and 13.25 °C, respectively. The magnitude of the difference between the temperatures reached on the external and internal face of the wall were smaller, showing the efficiency of the green facade; the greatest magnitude of the difference for the day of maximum temperature occurred in winter (3.45 °C), while for the day of minimum temperature it occurred in summer (4.1 °C). The IS proved to be very effective in explaining the role of vegetation in the temperature of the external facade, especially for the days of the hot seasons (proved from the analysis of ∆𝑇�𝑎�𝑓�). As for the possible relationship between the IS and the temperature difference of the internal and external facades, it was not conclusive, due to the heat flow that can occur on the wall of the building that is not completely shaded by the green facade. These results demonstrate the potential of shading the green facade to reduce the local thermal loads of a building, especially in summer.