Interaction effect of room opening and air inlet on solar chimney performance

Solar chimney has been frequently adopted in buildings to save energy by enhancing the natural ventilation. Although its optimization studies have been frequently taken previously, most of them have focused on the configuration of solar chimney but ignored the air inlet, even though its significant influence has already been confirmed. The interaction between the air inlet and room openings (e.g. window and door) is critical to improving the solar chimney performance, but the related interaction mechanism is still not known. Interaction of room opening and air inlet on solar chimney performance was analysed under both natural ventilation and smoke exhaustion modes. Numerical results of 19 scenarios were first validated by reduced-scale experiment tests. Another 25 numerical scenarios for full-scale solar chimney room with different heights of air inlet (0.1–2.3 m) and window (0.6–1.8 m) were analysed. It was known from numerical results that the height of window shows limited influence on flow rate under natural ventilation mode but the obvious effect on both flow rate at the air inlet and the total flow rate (both window and air inlet) under smoke exhaustion mode, especially when the window centre is higher than wall centre. Scenario, when both the window and air inlet are at the vertical centre of the wall, shows the best performance of both natural ventilation and smoke exhaustion. An empirical model was also developed to predict the flow rate through the air inlet under smoke exhaustion. Critical conditions for air inlet to exhaust smoke were determined which happens when the neutral plane is almost no lower than the window centre.