Computational Investigation of Different Taper Ratios and Chimney Divergence Effects on Solar Chimney Power Plant Performance

Solar chimney power plants (SCPPs) are a promising renewable energy technology whose performance is strongly influenced by geometric configuration. This study investigates the effects of collector taper ratio (TR) and chimney divergence ratio (CORR) on the thermo-fluid behavior and performance of SCPPs. Seven new configurations incorporating convergent and divergent collectors, upward- and downward-sloped absorbers, and a divergent chimney are systematically evaluated against a conventional design. The numerical model is validated against previously reported experimental and numerical results. The results show that the combined modification of the collector, absorber, and chimney significantly improves thermal and aerodynamic performance. The temperature rise increases from 19 K for the conventional configuration to 29.5 K for TR = 4, CORR = 2.2, representing a 55.3% increase. The maximum chimney velocity reaches 4.2 m/s, compared with 2.5 m/s for the conventional case. Collector efficiency increases from 11% to approximately 30% for TR = 9, CORR = 2.2, while chimney efficiency increases by approximately 137%. The theoretical power available in the chimney airflow increases from 0.15 W to approximately 1.0 W. Overall, coordinated geometric modifications substantially enhance SCPP performance and provide useful guidance for improved system design.