Desempenho lumínico e termoenergético de diferentes tipologias de fachadas envidraçadas, em um edifício comercial, no sul do Brasil

Abstract

The use of daylight is a strong ally to reduce energy consumption in office buildings, as it minimizes the costs of artificial lighting, in addition to providing benefits for the health and well-being of users. However, if, on the one hand, daylight is desirable, on the other hand, it can increase thermal gains and raise the presence of excessive illuminance in internal spaces. Hence, this work aimed to evaluate the balance between the daylighting and thermoenergetic performances in a commercial building model with different types of glazed façades, located in the Brazilian Bioclimatic Zone 2 (BZ2), considering the impact of daylight on both the visual comfort of its occupants and in the thermal load of the building. The method adopted was the evaluation though dynamic computer simulation, performed by using the Rhinoceros software with the ClimateStudio plugin for daylighting and EnergyPlus for thermoenergetic simulations. From the definition of a case study, a Base Case (BC) was developed, which served as a comparison for the following Reference Cases (CR): semi-curtain wall with blindtype shading devices and different types of glass, curtain wall with and without perforated screen shading with different percentages of perforation, in addition to different double skin façades configurations. Results showed that, within the context that was analyzed, the cases of double skin façade in which the inner layer corresponded to a traditional façade (closing in masonry and glass framed in the frames) presented one of the best points of balance between the daylighting and thermoenergetic performances. Besides, it was observed that a fixed-shading curtain wall with a 50% perforation can favor the thermoenergetic performance of the building, in addition to guaranteeing acceptable levels of daylighting with fewer glare problems. Proper choice of the external glazing of the building proved to be a determining factor for its energy efficiency, while the addition of automated blinds promoted greater light quality. On the other hand, the increase in the window-to-wall ratio (WWR) increased energy consumption for cooling the building and visual discomfort every time. The cases with curtain wall and double skin façade in which the inner layer corresponded to a semi-curtain wall or a traditional one contributed to the overheating of the internal spaces. The variation in the depth of the ventilated cavity influenced the results only in cases with lower WWR of the inner layer, in which smaller cavities showed to be more effective.