Natural Ventilation via Courtyards: Theory & Measurements.

Existing regulations concerning the design and construction of residential buildings which are naturally ventilated via courtyards and lightwells have origins in daylighting rather than in aerodynamics. The design of narrow, high-sided courtyards which achieve healthy . conditions for occupants, has long been a problem and a subject of various guidance and research, although many doubts and gaps in knowledge still remained. The work described below resolves these problems, and the coherent theory developed may lead to clearer guidance on the design of courtyards for natural ventilation. A fresh approach was adopted using computational fluid dynamics (CFD) software as an integrated technique in combination with measurements at both model and full scale. The adequacy of infiltration and ventilation rates in rooms opening onto the courtyard was also assessed. The salient results were used to develop a coherent descriptive model which explains the apparent discrepancies in earlier work and enabled revised design guidelines to be presented.