Numerical Investigation of Flow and Performance Characters of Diverged Chimney Solar Updraft Tower

Abstract

The paper focuses on the flow and performance analysis of diverged chimney-based solar updraft tower (DCSUT) plant. It investigates the effect of chimney divergence angle (θch), ambient temperature (Tamb) and solar flux (I) variation on the system performance. A 3D computational domain of DCSUT plant was modelled. Turbulence and radiation models were considered for evaluating the flow and performance characteristics. The results from the study look promising and found that the optimum performance of the SUT plant was noticed at θch of 2°. The velocity of air and power potential of the system was enhanced by 59.4% and 312.5%, respectively, than θch of 0°. The increase in I and Tamb also enhanced the flow and power potential of the plant. Due to an increase in Tamb from 293 to 318 K, the air velocity at the chimney base (CB) increased from 2.3 to 4.9 m/s (which is 113% enhancement). The collector temperature increases from 313.4 K to 350.4 K with an increment in I from 600 to 1200 W/m2. The velocity of air near CB, temperature, power potential and overall efficiency of the plant were determined as 3.52 m/s, 315.9 K, 1.62 W and 0.0112%, respectively. Furthermore, the optimized data of the DCSUT plant was compared with the conventional cylindrical chimney-based solar updraft tower (CCSUT) plant and found good matches.