Optimization of Narrowed Chimney Section Height for Improving Flow and Performance Features of a Solar Chimney Power Plant: A CFD Approach

The depletion of fossil fuels and climate change are major worldwide problems. Unlike hydrocarbon resources, solar energy is a clean, inexhaustible, and sustainable power source to meet all of humankind’s energy demands. Solar chimney power plants (SCPPs) having a simple design are capable of generating large-scale solar powered electricity. The systems have three primary components: a chimney, turbine, and collector. The optimization of the chimney geometry plays a key role in achieving the peak efficiency of SCPPs. In the current work, a three-dimensional (3D) model on the basis of the Manzanares prototype with a chimney height (H) of 194.6 m and radius (R) of 5.08 m is developed to identify optimal height for the innovative constricted chimney section configurations via ANSYS FLUENT. The height of the narrowed chimney sections varies as 1/4, 1/8, 1/16, and 1/32 of H for a fixed radius as 1/3 of R. The findings indicate that the power output (P_o) increases with decreasing the narrowed section height from H/4 to H/32 owing to enhanced mass flow rate and turbine pressure drop. The highest P_o of 65.9 kW is gained with the configuration with the height of H/32 and P_o enhances by 43.3% compared to the base case at 1000 W/m². The novel equations are improved from the numerical data to estimate the performance features. Besides, the impact of the narrowed section radius on the performance is examined to optimize the dimensions of the constricted section. It is found that a decrease in the narrowed section radius from R/3 to R/5 for a constant height of H/32 leads to a reduction in P_o by 1.2% because of a remarkable decrease in mass flow rate. H/32 and R/3 can be optimum height and radius value for the reduced chimney section to augment system efficiency.