An exploration of courtyards for passive climate control in non-domestic buildings in moderate climates

The use of passive systems for climate control in providing indoor thermal comfort minimizes the global trends in increasing energy demand for active systems of climate control, which has unacceptable negative impacts on the natural environment. However, this concept is neglected in non-domestic building sector in Australia and a reevaluation of die concept becomes important. Despite abundant research and literature on die passive performance of buildings in general, the use of "courtyards" in buildings for passive climate control in particular has received only limited appraisal in architectural scholarship. The findings that do exist emphasise the potential of courtyards as microclimatic modifiers in hot dry and tropical climates. The literature gives evidence that only a very little has been investigated either empirically or theoretically on the potential of this concept for moderate climates, for example southeast Queensland in Australia and no real design variables and conditions that orchestrate courtyards as microclimatic modifiers have been identified. It is hypothesized that courtyards as microclimatic modifiers promote indoor thermal comfort in non-domestic buildings in the moderate climates. This research explores the conditions where such an application operates, and then proposes a model, founded on a theoretical investigation using literature and findings related to passive climate control by courtyards in other climates in the world. The model, which identifies specific design variables and conditions that are essential for courtyards to function as passive strategies and thus microclimatic modifiers, is justified through the findings from an empirical field investigation, which includes a real courtyard building found in this climate, using micro-meteorological equipment. The thesis of the research claims that the degree to which courtyards encourage passive climate control depends greatly on the manipulation of the building enclosure, building geometry and thermal mass in the envelope in respect to access points to the prevailing wind flow. The applicability of courtyards for passive cooling needs an appropriate integration of these variables in a way ensuring the courtyard acts as an air funnel discharging air into the sky, instead of the common understanding that the courtyard acts as a suction zone inducing air from its sky opening. Ventilation through lower level openings in the envelope, where optimum shading is found, contributes to this airflow pattern while maintaining the courtyard's swing of air temperature below the corresponding swing of ambient weather. Potential for passive heating is seen with the absence of wind flow and presence of solar gain to the courtyard, an effect primarily attributed to the building geometry and enclosure. The significance of the thesis findings is that the outcome sets out design consequences and then generalizes for wider use of environmentally sustainable design principles in future practice concerning courtyards in non-domestic buildings in the moderate climates in achieving environmental goals.