Thermo-fluid dynamic numerical analysis of vestibule functions in a solar updraft tower

Solar updraft towers (SUTs) represent a promising avenue for renewable energy generation, leveraging solar energy to drive their operation. Although the collector of SUTs is generally vacant, ongoing research have focused on auxiliary structures inside the collector aimed at enhancing the overall efficiency. This study delved into the computational fluid dynamics (CFD) analysis of a SUT model featuring a 5 m radius collector and a 12 m height chimney. Specifically, we investigated the vestibule functions which created by implementing baffle inside the SUT collector with various radial locations. Through rigorous examination, the thermo-fluid dynamic effects of both roof-mounted and bottom-mounted baffles on SUT performance were explored, aiming to ascertain the optimal vestibule parameters. The vestibule was found to mitigate the backward flow leakage, isolate the inner room from the outside air, and enhance the heat exchange efficiency of the main flow. Notably, when the roof-mounted baffle was positioned at a radial location of 4.5 m, a remarkable 11.4 % and 28.1 % increase in the mass flow rate at the chimney outlet and kinetic power were achieved, respectively. These findings highlight the significant performance improvements achievable through the incorporation of a vestibule within SUTs of a given scale.