This study explores the use of solar chimneys to harness solar radiation, generating a chimney effect that promotes natural ventilation in buildings. However, the performance of double-channel solar chimneys is heavily influenced by their installation conditions. We propose an optimized double-channel solar chimney with a deflector placed at the base of the collector. Through numerical simulations, we analyze how different deflector installation conditions affect the ventilation performance of the optimized system. Key parameters for the deflector installation include its angle and length. Our findings reveal that the optimal configuration for the double-channel solar chimney occurs when the deflector has a horizontal angle of γ = 35° and a length-to-diameter ratio (l/D) of 0.3. Under a solar radiation intensity of 800 W/m², the optimized system achieved a ventilation rate of 0.185 kg/s and a thermal efficiency of 41.2%. Compared with conventional double-channel solar chimneys, this configuration enhanced ventilation performance by 8.2% and increased thermal efficiency by 7.4%. In the calculations, the optimized system resulted in a 13.6% reduction in energy consumption, underscoring its potential for sustainable architectural design.