The present paper investigates the effect of geometrical parameters by using energy and exergy analysis and hydrophobic surfaces as an innovative method were proposed to enhance the performance of Solar Chimney Power Plant (SCPP). Furthermore, the best radiation model for SCPP simulation was represented. Hereupon, firstly large-scale SCPP using reverse fan model was validated based on Manzanares constructed power plant. For reducing the computational cost, nine different small scale 3-D models defined respect to prior experimental study under Tehran-Iran meteorological condition. The first and second laws of thermodynamics were studied, and an optimization was done for representing the best functional diameter, height and turbine pressure jump by the means of improvability rate and clarified optimization factor. Results show that the optimal state of chimney can be defined in relation to a certain condition; hence, the geometrical parameters under investigation should simultaneously be evaluated in system designs. Furthermore, applying the slip condition on walls to simulate hydrophobic surfaces was attempted to reduce shear stress on walls which led to roughly 11% performance enhancement. Consequently, Discrete Ordinates (DO) radiation model could be trusted based on its more factual outcomes with referred to prior experimental results of Heat flux method.