Numerical study of buoyancy-driven natural ventilation in a simple three-storey atrium building

A simple three-storey atrium building was modeled to investigate the development of buoyancy-driven natural ventilation airflows induced by solar radiation and by the heat sources present on each floor of the building using a validated Computational Fluid Dynamics (CFD) model. The Reynolds Averaged Navier–Stokes (RANS) modeling approach with the SST-k-ω turbulence model and the Discrete Transfer Radiation Model (DTRM) was used for the numerical solution. The steady-state governing equations were solved using a commercial CFD solver FLUENT©. The air flow patterns, temperature distributions and the ventilation flow rates as predicted by the CFD model for this case study are presented in this paper. The ventilation flow rates were compared in non-dimensional form with the analytical design curves found in literature developed through the use of an analytical approach for a simple geometry atrium building. It was found that the CFD predictions agreed with the general trends described by the analytical model. The effect of solar intensity on the buoyancy-driven ventilation flow rates and the temperature distributions during the day-light hours and at different geographical locations was also investigated.