Interaction Between Wind and Buoyancy Effects in Natural Ventilation of Buildings

Abstract

Design of natural ventilation systems for many types of building is based on buoyancy force. However, external wind flow can have significant effects on buoyancy-driven natural ventilation. Simulation has been carried out for combined wind- and buoyancy-driven natural ventilation of a building with two wings of offices and a central atrium. Results show that wind would adversely affect the air flow patterns in the building designed with buoyancy-driven natural ventilation. Wind can simultaneously assist and oppose buoyancy in the windward and leeward wings, respectively, whereas buoyancy can oppose wind-driven flow in both wings. To achieve or maintain a desired environmental quality in the naturally ventilated building would require intelligent control of ventilation openings and/or careful consideration of winddriven ventilation at the design stage. The importance of measurements of variables such as pressure, velocity and temperature for real size buildings is also highlighted.