Numerical investigation on performance of solar chimney power plant by varying collector slope and chimney diverging angle

In this study, a parametric three dimensional computational fluid dynamics (CFD) analysis of solar chimney power plant was performed to illustrate the effects of collector's slope and chimney diverging angle on performance of Manzanares prototype. Numerical models were incorporated with solar load, DO (discrete ordinates) and RNG k-ɛ turbulence models. Firstly, CFD simulations results were validated by comparing them with the experimental data of Manzanares prototype and then, on the basis of robustness of numerical methods adopted, several numerical simulations were performed on varying collector's slope and chimney diverging angles to improve the performance of solar chimney. Numerical simulations were performed at chimney diverging angle = 1°-3° and at collector slope = 4°, 6°, 8° and 10° sequentially, while all other parameters were kept constant. Based on computed results, it was discovered that both velocity and temperature increases with increasing collector's slope due to enhanced heat transfer and mass flow rate, but simultaneously higher collector slopes also deteriorate the smooth air flow by developing vortices and recirculation of air, which obstructs the air flow and may reduce the overall performance. In addition, chimney diverging angle = 1° raises the velocity from 9.1 m/s to a remarkable value of 11.6 m/s; therefore, this diverging chimney approach is conceived to be a beneficial tool in improving performance of solar chimney power plant.