The goal of this paper is to study and optimize the conical chimney angle (α) of a divergent solar chimney power plant (DSCPP) by using CFD technique. The local airflow characteristics were analyzed in four configurations with different conical angles α = 0°, α = 3°, α = 6° and α = 9°. The first design is validated experimentally by using a pilot prototype build at the National School of Engineers of Sfax, Tunisia. In addition, some experimental results of the temperature, the velocity and the power output were presented during a typical day. A novel mathematical correlation was developed to prove the effect of the conical angle and the DSCPP scale on the power output. In fact, the relationship between the optimum conical angle and the system scale was performed based on both quadratic and cubic regressions. The computational results ensure that the conical chimney angle presents a parabolic tendency with the turbulence airflow characteristics and the power output. The performance of the DSCCP was degraded since the conical angle is greater than α = 3°. Furthermore, the optimum angle decreases with an increasing system scale. A commercial solar chimney with a conical angle around α = 1° presents an efficient system.

Solar chimney is nowadays an important source of renewable energy, especially in the hot region of the world. In this paper, the solar chimney is investigated based on the ambient conditions of Tunisia. An experimental setup is developed to study the solar chimney under the Tunisia weather conditions. Numerous simulations are performed to study the chimney diameter effect. The airflow characteristics are analyzed for the different chimney diameters. The depression zone in the chimney inlet increases with the increase of the chimney diameter. Consequently, the velocity value increases. The comparison between the numerical and the experimental results shows a good agreement.