Study on optimizing design of solar chimney for natural ventilation and smoke exhaustion

Solar chimney has been primarily utilized for natural ventilation, but its application to smoke exhaustion was rarely explored. A 1:3 reduced-scale test platform with a dimension of 1.5 m × 1.5 m × 0.9 m (height) was used to optimize solar chimney under natural ventilation and smoke exhaustion, considering four influencing factors, including height of cavity inlet from the floor (0.2-0.8 m), cavity depth (2.5-17.5 cm), solar radiation (400-1200 W/m2) and fire size (6.8-15.8 kW). Both natural ventilation and smoke exhaustion follow the same trend along the air inlet height and cavity depth, which confirms its viability on smoke exhaustion under fire condition without compromising the performance of natural ventilation. Experimental results suggested a chimney configuration of 0.5 m high air inlet and 12.5 cm cavity depth with optimized functions. External radiation shows obvious benefit on enhancing natural ventilation, while its influence on smoke exhaustion is limited. An empirical model was developed to predict the flow rate under normal and fire conditions. The outcomes of this study provide a technical guidance for the design of solar chimney under scenarios of both natural ventilation and smoke exhaustion.