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An experimental study of the effects of surface openings on air flow caused by wind in courtyard buildings.

Article Excerpt
Abstract: One of the modifications to increase the ventilation performance of buildings with courtyards is to create cavities to convey the air horizontally in the courtyard by the wind. This also decreases the cooling load, indirectly, in temperate or hot-humid climates. This study examines and attempts to explain the effects imposed by openings created in the architectural mass of courtyard buildings upon the velocities of airflows within such courtyards. The research was conducted through tests in a wind tunnel. The results from this study indicate that for buildings containing openings arranged in configurations different from those of courtyard buildings, openings located on perpendicular surfaces increase the velocities of airflows within courtyards in proportion to their dimensions and positions.

Keywords: Air movement, Building climate, Courtyards, Natural ventilation, Passive cooling, Wind effects

Introduction

For centuries, planners and designers have been considering the wind or air flows natural data for building components on various scales including city, region and country (Ansley, Melbourne & Vickery, 1977). Various passive or natural air-conditioning methods using the wind are employed by architects and city planners to lower cooling energy costs in hot regions (Awbi,1994). Air movement, as a passive airconditioning media, may be valuable in order to provide inbuilding ventilation especially in the hot and humid climate zones. In hot and arid climates, the traditional courtyard building form ensures air flows through natural ventilation between wind pressure (Adil & Al-Mumin, 2001; Megren & Al-Saud, 2001; Nasser, Al-Hemiddi & Khalid, 2001; Rajapaksha, Nagai & Okumiya, 2003; Ratti, Raydan & Steemers, 2003). The courtyard building form should be improved to increase its ventilation performance, especially for humid climate regions. In this context, the other openings pertaining to the building which may change the air movement effectiveness incurred with the wind effect in the buildings with courtyards, should be studied carefully. Many numerical or experimental studies have been conducted on the insolation aspects of courtyard buildings. However, only a limited number of studies have been conducted on wind effects. Not only may the building itself have a courtyard, but also may produce an open space in courtyard form as part of an urban structure together with several buildings (Lawson, 1980). When buildings are combined to each other as an open courtyard within the settlement area, the wind either flows over the courtyard or circles in it. The surface area of a courtyard and the position of the courtyard openings against the wind (and the width or total width of the openings) are variables affecting the qualitative and quantitative character of the wind within the courtyard (Gandemer & Guyot, 1976).

Layout and position of outdoor spaces affect the discomfort parameter of pedestrian spaces. The discomfort parameter occurs at the highest level in spaces exposed to the wind and at medium levels in spaces fully covered or...

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