This paper presents a computational fluid dynamics study on a solar-chimney power plant with an inclined collector roof. A three-dimensional model using the RNG (Re-Normalisation Group) k−ε turbulence closure is simulated. The discrete ordinates non-gray radiation model is used to implement the radiative-transfer equation. To simulate solar irradiation, the solar ray-tracing algorithm is employed. A parametric study is performed to illustrate the effect of the collector configuration on the performance of the Manzanares power plant. In this approach, the roof inclination is adjusted by increasing the outlet collector height, while the inlet collector height is fixed to the height of the collector of the Manzanares solar chimney pilot plant. The results showed that changes in the collector-roof inclination affect the convection pattern through the collector, which results in an increase in the mass flow rate of the system.