Natural Ventilation of Buildings: From Fluid Mechanics to Architectural Design Guidance

Abstract

Over the last two decades, natural ventilation of buildings has rapidly established itself as a viable low-energy alternative to air-conditioning and mechanical ventilation systems. With careful design, natural ventilation has the capacity to reduce the energy expenditure of buildings and can provide a comfortable indoor environment for occupants. Undeniably, a successful natural ventilation design calls for an integrated approach, ideally involving architects and ventilation engineers working closely together through all stages of a building design process. However, establishing an environment conducive to open communication and shared knowledge exchange between both camps may be difficult in a practical setting, given that both have developed their own unique set of language conventions, philosophies, methods of thinking and problem-solving. Further to this, there is an apparent delay in the time taken for information on natural ventilation to be transferred from the fluid mechanics literature (where fundamental developments in the science underlying and explaining natural ventilation flows tend to be made) into architectural design guidance, which further exacerbates the barriers to knowledge exchange in practice. This research endeavours to serve as a springboard for fostering the transfer and delivery of information on natural ventilation from the fluid mechanics literature to an architectural audience. Focus is on the intuitive value of a simplified mathematical approach as a vehicle with which to model and explain natural ventilation flows. Based on this approach, rapid and intuitive guidance for use in preliminary design is developed and proposed to inform the suitable sizing of façade openings to meet specific ventilation targets. Our proposed guidance, which centres around hand calculations and the use of visual charts, is anticipated to be readily usable by architects and engineers, thereby facilitating two-way communication and dialogue between both members in a design process. Moreover, attempts are made to gain direct insight into the information needs of young architects in the context of a natural ventilation design with a view to improving our current understanding and means of conveying technical information to architects. It is hoped that this research will prove of interest to those engaged in low-energy building design, whether as practitioners or academics, from architectural, building services or wider engineering backgrounds.