Multiple Flow Regimes in Stack Ventilation of Multi-Storey Atrium Buildings

Passive stack ventilation is a key feature of sustainable building design and has particular potential for use in tall, multi-storey buildings. However, natural ventilation flows through multiply connected spaces may not behave as expected. Recirculation of air through occupied parts of the building and bidirectional exchange flows at ventilation outlets may compromise the intended ventilation scheme resulting in an uncomfortable indoor environment. Using a simple mathematical model of stack ventilation in an example four-storey atrium building, we determine the vent areas at which transitions between the desirable and undesirable flow regimes occur and, hence, determine what constitutes an effective design.