Numerical Investigation of Effective Parameters on Efficiency of Solar Chimney

The environmental pollution crisis caused by the excessive use of fossil fuels and the risk of the destruction of natural resources and reserves, as well as the excessive production of greenhouse gases and, consequently, global warming, led many energy researchers to use renewable energy As a fossil fuel alternative. Solar chimneys are one of the types of renewable energies that have been taken into consideration by researchers over the past decade. Solar chimney power plants are such plants which include solar collectors, chimney and turbines that are placed at the entrance of the chimney. The aim of this study is numerical modeling of a solar chimney power plant prototype model built in Tehran University and investigation of the affecting parameters on enhancement the air velocity within it. The two dimensional numerical modeling based on finite volume method is conducted using  standard wall function turbulence modeling through an optimum mesh. The numerical results show good agreement with experimental data with maximum 6 percent difference in magnitude. Comparing with similar studies, modeling the power plant without using the energy storage properties of the earth by using constant heat flux on the collector regardless of the environmental radiation conditions has been conducted in the present research. The results show that increasing the chimney height, collector radius and collector height and decreasing the radius of the  chimney would result in increasing 76 percent in air velocity through the chimney (from 1.7 m/s in the experimental model to 3m/s) and consequently improving the model efficiency. Furthermore, among the effective parameters, collector and chimney radius play greater roll on increasing the air velocity through the chimney. The results of this research may play significant role on optimizing the constructed solar chimney power plant model.