Transient flows in displacement ventilation enhanced by solar chimney and fan

Theoretical analysis was carried out to develop an unsteady-state model for displacement ventilation in buildings with solar chimneys and fans. The influence of solar radiation intensity and the height of the solar chimney on the interface height, reduced gravity and natural ventilation rate was analyzed, as well as the mechanical ventilation rate and the area ratio of the openings. It was found that the interface height and airflow rate increased significantly with solar radiation intensity and the height of the solar chimney for a relatively smaller time scale ratio, but reduced gravity increased significantly for a larger time scale ratio. When the mechanical force assisted the thermal force, the increasing mechanical ventilation rate and area ratio increased the interface height and total ventilation rate, but decreased the natural ventilation rate in hybrid ventilation.