Digital tools for the morphological design of the naturally ventilated buildings: Case study: analysis of the wind driven ventilation potential of linear isolated blocks

Naturally ventilated buildings have great potential in terms of comfort and energy saving. However their design process is difficult, as the effectiveness of the ventilation is affected by many parameters. We propose a support for the design of naturally ventilated buildings which takes into account the building shape and the positions of the openings. In particular, we focus on the interaction, expressed by the pressure, between the shape of the building and the wind. The wind produces a pressure distribution over the building’s envelope, that activates an internal airflow through the openings. The pressure difference between any two points lying on the envelope is considered as the force driving of the natural ventilation. This force depends mainly on the aspect ratio of the building. Changing this parameter in a specific range, we represent some different shapes. Then we reduce the problem from 3D to 2D studying the airflow around the cross-section of the building. This reduction is legitimated only for linear block buildings, if one neglects the boundary effects of the building’s endings. So we compute the pressure distributions by CFD simulations of a stationary flow past a rectangular obstacle in a flow canal. Hence, for each configuration, we compute the pressure values and create some plots useful for the positioning of the inlets and the outlets. Then we calculate the value of an indicator, measuring the global performance of ventilation of the building. This indicator is the averaged pressure coefficient difference of all possible ventilation openings of the building. Finally, we plot the ventilation potential for the linear block’s morphological family to compare all configurations. The graphics are two complementary graphical tools that we can combine, for an easier morphological conception of naturally ventilated buildings. They can be used by designers without any particular skills in aerodynamics.