Influência de muros vazados laminados no desempenho da ventilação natural em habitações de interesse social

Abstract

The wall with its physical and symbolic dimensions is an element present in Brazilian housing. Its existence represents, among other factors, one of the numerous palliative responses to the complex problem that characterizes urban issues such as violence and insecurity. From the perspective of thermal comfort, these high walls have become significant barriers to airflow with impacts on the use of natural ventilation of ground floor buildings, especially when it comes to buildings in small lots such as social housing. The use of porous walls can be an interesting resource to reduce the effect provided by these components and may present a favorable potential for better use of natural ventilation without affecting the sensation of privacy and vulnerability. This work presents an evaluation of the natural ventilation performance produced by different configurations of laminated porous walls, aiming the thermal comfort in social housing in a hot and humid tropical climate. Parametric analyses were used through simulations based on the Computational Fluid Dynamic simulation (CFD). Three types of walls and their variations were applied in existing social housing. The computational three-dimensional models were submitted to analysis in the ANSYS CFX 18.1 program. The main parameters analyzed were: position and direction of the porous component, the porosity of the front wall (25% and 35%) and angle of wind incidence (45º, 90º, and 135º). Qualitative analyses were performed considering the wind flow distribution patterns, and quantitative analyses were performed considering the data obtained for wind speed and pressure coefficients (Cps). The main result of the research demonstrated that the porous walls models, in general, showed better values in the wind circulation patterns, in the air velocity, and in the Pressure Coefficients (Cps) in the leeward region of the wall than the without openings models. Especially the configuration with horizontal blades directed downwards and with the largest porosity (35%). However, it was observed that these improvements were not reflected in improvements of the natural ventilation conditions in the internal space because in this predominated of wind stagnation zones. It was evidenced the need for insertion of the porous walls, above 30% porosity, allied to other strategies of natural ventilation.