Effect of window geometry on wind driven single sided ventilation through one opening

Abstract

Natural ventilation (NV) through a single openable window (SS1) is the most common passive cooling strategy for small rooms. SS1 NV driven by wind can be propelled by pressure variations along the opening or, in medium and large buildings, wind driven shear. This paper presents an experimental study of the impact of typical window geometries on SS1 NV flows driven by wind shear parallel to the building façade. The experiments were performed in two complementary setups, a wind tunnel test of a reduced-scale SS1 and a full-scale SS1 room subjected to artificial wind shear that was equipped with eight different windows.Results show that the combination between window geometry and wind direction has a large impact on SS1 ventilation. For the same window area, results show that in combinations where the window directs the wind flow towards the room, the flow is up to four times larger. In contrast, when the combination is unfavorable, the window reduces the wind driven SS1 flow by up to 23%. This study identified the best window configurations for wind driven SS1 in dense urban environments. By combining average results for measured wind velocities in street canyons with the flow coefficients for typical window geometries, it was possible to propose simple correlations for wind driven SS1 in urban environments that more precise than existing models.