A CFD based approach for determining the optimum inclination angle of a roof-top solar chimney for building ventilation

Abstract A CFD based procedure is described to identify the optimum inclination angle of a small-scale roof-top solar chimney for maximum ventilation performance. The absorber wall of the chimney under consideration is 500-mm long and the air gap width is 40 mm. Firstly, CFD simulations are performed on a two-dimensional solar chimney model with inclination angles varying from 30° to 90° relative to the horizontal plane under different heat fluxes. Subsequently, a mathematical procedure using the CFD data to estimate the ventilation performance of the solar chimney at different inclination angles under real climate conditions is described. The procedure accounts for the effect of the inclination angle on receivable solar irradiance and is applied to three Australian cities, corresponding to three different latitudes. It is found that the optimum inclination angle varies from 45° to 60°, depending on the latitude and season of operation.