This paper aims to compare the thermal performance of four different configurations of absorber wall for the solar chimney-shaped channels. A detailed energy and exergy analysis has been performed for various solar radiation intensities. Using Computational Fluid Dynamics technique, the four configurations are examined in order to determine the optimal configuration. The configurations are described by a flat corner, rounded corner, triangle corner and trapeze corner. The Computational Fluid Dynamics results were validated against experimental data from the literature, and a good agreement between the prediction and measurement was achieved. The results indicate that (1) the exergy and energy efficiencies increase with solar radiation and the energy efficiency is always higher than the exergy efficiency, (2) the energy efficiency of triangle corner is 50% higher than that of the trapeze corner configuration, 67% higher than that of the rounded corner and 2% higher than that of the flat corner when the solar radiation intensity is 480 W m(-2), (3) the triangle corner increases the air temperature and pressure in the solar chimney which results in an optimum air mass flow rate which enhances the ventilation and (4) the comparison among the four configurations shows that the triangle corner configuration results in higher efficiency when a solar chimney is used as a natural ventilator.