Performance evaluation of hybrid solar chimney for uninterrupted power generation

Abstract

Solar chimneys have the drawback of being unproductive at night. This study proposed a hybrid solar chimney integrated with an external heat source to complement solar energy for uninterrupted power generation. Flue-gas channels were utilized to supply air into the collector passage. The hybrid arrangement was investigated experimentally and numerically. An experimental model comprising a 6 m-diameter solar air collector, 6.65 m-height chimney, and four flue thermal channels was designed and fabricated. The hybrid system was further simulated using ANSYS-Fluent. The numerical procedure was validated by comparing with experimental measurements for a conventional solar chimney with mean differences of 8.7% and 7.8% in air flow velocity and air temperature rise, respectively. Results showed that the hybrid approach considerably enhanced the plant performance. The insertion of flue channels, even with no flue-gas flow, enhanced the velocity and temperature by 6.87% and 6.3%, respectively measured at the chimney base. Simulation results with 0.0015 kg/s at 116 °C flue gas in the thermal channels demonstrated that the air-mass flow rate and collector efficiency enhanced by 12.0%, and 64.0%, respectively. This study proved that the proposed technique can resolve the setback of night operation of solar chimney power plants and enable 24/7 power production.