Experimental investigation of a solar chimney natural ventilation system.

Natural ventilation driven by a solar chimney attached to a single-room building is investigated experimentally with a small-scale model using a recently developed fine bubble technique. Parameters studied in the experiments are the cavity width of the solar chimney, the solar radiation intensity, the height of the solar chimney, the room inlet area and the solar chimney inlet area. Results showed that for given building geometry and inlet areas, there is an optimum cavity width at which a maximum ventilation flow rate can be achieved. This optimum cavity width, which is independent of the solar radiation intensity, was found to be dependent on the chimney height, the size of the room inlet and the size of the solar chimney inlet. Comparisons between the measured ventilation flow rate and predictions by a simple theoretical analysis presented in this paper suggested that theoretical models, which assume uniform temperature distribution across the chimney width, may overpredict the chimney performance at some situations and should be used with care.