Improve passive ventilation effectiveness of buildings through open-sided air cowls.

Currently, in the design of new buildings and retrofit of old buildings, attention is turning towards a more integral energy design with focus not only on thermal insulation and airtightness but also on optimal use of sustainable technologies such as natural ventilation. There is a tendency for buildings to be designed in order to utilise the outdoor environment to create an acceptable indoor environment, whenever it is beneficial. Passive ventilation and natural cooling are sustainable energy efficient and clean technologies. These technologies are well accepted by occupants and should therefore be further encouraged wherever and whenever possible. Unfortunately, until now, a widespread use of ventilation is hampered by the poor command of knowledge of natural ventilation technologies. The aim of this project is to study the crucial techniques to improve the passive ventilation efficiency for office and commercial buildings, i.e., the optimization of natural ventilation inlets/outlets configuration, opening areas and the characteristics of air flow through inlets/outlets. In this paper, based on environmental wind tunnel laboratory tests, a series of scale modelling and full scale investigations about open-sided inlet/outlet configuration are performed. Through the research on air flow conditions for different strategies and temperature differences, the local resistance coefficients, the discharge coefficient as well as the characteristics of air flow can all be demonstrated. Following this work, a design procedure for choosing inlet/outlet natural ventilated office or commercial buildings will be recommended when the research is completed.