Natural ventilation

Buoyancy-driven ventilation

Natural ventilation in buildings can rely mostly on wind pressure differences in windy conditions, but buoyancy effects can a) augment this type of ventilation and b) ensure air flow rates during still days. Buoyancy-driven ventilation can be implemented in ways that air inflow in the building does not rely solely on wind direction. In this respect, it may provide improved air quality in some types of polluted environments such as cities. For example, air can be drawn through the backside or courtyards of buildings avoiding the direct pollution and noise of the street facade. Wind can augment the buoyancy effect, but can also reduce its effect depending on its speed, direction and the design of air inlets and outlets. Therefore, prevailing winds must be taken into account when designing for stack effect ventilation.