A influência de diferentes configurações do peitoril ventilado na ventilação natural de habitação de interesse social

Abstract

The potential of natural ventilation has not been well explored in buildings, although it being one of the main bioclimatic strategies indicated to promote termal comfort and energy efficiency. There are several variables that interfere in pattern of internal ventilation of environments and there are few studies about the use of devices to increasing natural ventilation in Habitation of Social Interest – HIS. This work aimed to analyze the behavior of natural ventilation inside the environments of a single-family building model of social interest, using “ventilative sills” with different closing flap configurations. The parametric analysis were made by a software of computer simulation named PHOENICS, that uses Computational Fluid Dynamics – CFD. 64 models were simulated resulting from the variation of 8 incidences of the wind, two wind speeds, being 2m / s and 4m / s, three positions of the closing flap of the ventilated sill and scenarios of use for the day and for the night. The use scenario for the day with open windows, internal doors and ventilated sills and the scenario for the night with closed windows and open internal doors and ventilated sills. For the analysis of the results, 256 images of visualization in plan were extracted, in different heights, according to the position of the occupants in each environment, being 0.6m for the user lying down, 0.8m sitting, 1.20m standing and 1.6m at the height of the center of the window. 144 sectional images of the models with “ventilative sill” were also extracted. The results were divided in two parts.The first part, being from the original project, showed that showed that out of 8 incidences of wind 4 are more favorable to internal ventilation of houses, in terms of speed, distribution and wind flow direction. The second part includes the analysis according to the position of the closing flap of the “ventilative sill” and the analysis of the influence of the angle of incidence and wind speed. The results show that all models of the original design had a wind speed in the center of the environments below 0.6m / s and after the insertion of the ventilated sill, 18.75% of the models reached a central wind speed equal to or greater than 0.6m /s. The poor performance related to the natural ventilation of the HIS model used is evident. The horizontal position of the ventilative sill’s closing flap directs the most intense wind flow to the bottom of the room and allows a larger effective opening area for ventilation of 0.4m2. The up position did not produce an upward wind flow throughout the environment and the down position directs the air flow to the lower regions. Finally, recommendations are made for the use of ventilated sills in homes.