Numerical analysis of the divergent solar chimney power plant with a novel arc and fillet radius at the chimney base region

Solar chimney power plant (SCPP) is an ingenius concept of harnessing the solar energy for the electrical power generation, provided their efficiency is enhanced significantly. The present work focuses on the improvement of the power generation and efficiency of the plant. A finite volume CFD code is developed in FORTRAN to deal with the axisymmetric domain of the SCPP. The effect of chimney divergence angle, collector height and a novel arc and fillet radius at the chimney base is studied. For the study, an SCPP with 3 m collector diameter and 3 m chimney height with 0.05 m radius of the chimney is considered. The height of the collector is optimised and found to be 0.04 m. Diverging the chimney results in more updraft which leads to more pressure difference and increased air velocity. Also, after an optimum divergent angle, further increasing the divergence angle results in a severe reverse flow at the chimney outlet. It is observed that 2 degrees divergent chimney is optimum which enhances air velocity by 59% and produces 290% more power than the conventional SCPP. Further improvement in the power is noticed by using the arc and fillet radii at the chimney bottom. After extensive analysis of the flow parameters, an optimum value of arc and fillet radii is proposed to be 0.1 m and 0.01 m respectively. It is noticed that for this optimum case, maximum available power is about 122% higher than the 2 degrees divergent chimney case without any arc or fillet. The proposed design has produced an overall increment of 770% in the maximum available power of the plant and about 154% increment in the mass flow rate compared to the base case. The proposed design also enhances the collector and chimney efficiencies by about 49% and 76% respectively.