Assessment of Outdoor Pedestrian Ventilation Performance While Controlling Building Array Scale and Density

In hot and humid regions of China, people experience great discomfort. Good ventilation improves human comfort by facilitating the discharge of heat in a region. None of the previous studies considered which scale is appropriate for the outdoor ventilation of building arrays, and the ventilation performance differs with the array size. Moreover, the building density has an upper limit in Chinese cities, and many studies overestimate this density. Based on these considerations, the neighborhood block is proposed to represent the scale of building arrays with the combination of the urban planning scale and climatic scale. Using this scale, the building density and representative building array configurations for hot and humid regions of China were determined. The outdoor ventilation of these building arrays at the pedestrian height was then studied via computational fluid dynamics simulations. The results show that, in the neighborhood block, an increase in the building height and length is beneficial for the mean velocity, whereas an increase in the building distance is not, and a staggered layout has a negative effect on ventilation. Furthermore, the semi-enclosed layouts are no better than the enclosed layouts in terms of ventilation and sunlight. Some contributions contradict the existing studies because of the selection of different array scales and densities, which prove their significance.