Natural ventilation assessment of an existing apartment building in the Mediterranean using time-dependent CFD

The benefits and limitations of time-dependent and steady state computational fluid dynamics simulations when evaluating natural ventilation were explored in a naturally ventilated case study apartment in the Mediterranean. For wind driven flows, indoor air properties responded quickly (i.e. within 1-min) to changing outdoor conditions, except indoor air temperatures (up to 30-min). The outdoor air temperature variations could reverse the flow direction during buoyancy-driven ventilation. Strong correlations between the steady state and transient simulation results were predicted (<1% error). Comparable indoor temperatures were found from simulations with both coarse and fine time steps, and up to 2% difference was found for indoor velocities.