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Natural Ventilation  »  Buoyancy induced ventilation

• Overview
• Description
• Impacts
• Examples
• References

Introduction

Buoyancy induced ventilation occurs when the air within a stack rises up due to temperature gradient between warmer air and colder air within the stack. The warm air rises in the stack, removed from the top and is replaced by cooler air at the inlet at the bottom. In tall buildings the use of ventilation shafts or building features such as atriums are effective, whereby the higher the ‘stack’, larger the cross-section and temperature difference. The Stack effect can be enhanced in combination other measures such as with earth cooling of the inlet air, trombe wall, double façade system etc.

Policy

Buoyancy induced ventilation is one of the baseline requirements in all the building energy codes as an effective passive strategy, both for energy savings and cost reduction.