Computational Investigation on Flow and Power Output of Solar Chimney Power Plants by Changing Collector Entrance Geometry.

The use of fossil fuels for generating power has leaded to the reduction of fossil fuel resources and many adverse influences involving climate change and environmental pollution. Solar energy has a potential to provide eco-friendly energy with a great energy supply for producing heat and electricity. Basic parts of the system are the collector, chimney and turbine. The collector is a vital component of the system and its geometrical features noticeably influence the power plant efficiency. In the current work, a three dimensional computational fluid dynamics (CFD) simulation of a SCPP based on the Manzanares prototype is performed to scrutinize the impact of collector entrance height (He) ranging from 0.75 m to 2 m on the solar chimney power output. Computational model is developed by employing RNG k-ε turbulence and discrete ordinates (DO) coupled with solar ray tracing models through ANSYS Fluent software. The model is validated using measured data published in the literature. The numerical results reveal that reducing He improves maximum velocity (Vmax), power output and pressure difference in the turbine at the expense of decreasing air mass flow rate. The highest velocity of 19.45 m/s is achieved with He = 0.75 m and Vmax enhances by 36.20% compared to base model with He = 1.85 m at 1000 W/m2. Besides this configuration provides the maximum power output of 66.51 kW and augments power output to 31.74% compared to the base case at 1000 W/m2. [ABSTRACT FROM AUTHOR]