Wind driven natural ventilation in courtyard and atrium-type buildings.

This study investigated the effectiveness of wind-driven natural ventilation in
courtyard and atrium-type buildings, particularly in the context of ventilative cooling.
Courtyard and atrium buildings are currently enjoying great popularity. Perhaps a
primary reason for their revival comes from the energy and environmental awareness of
the current period, in which courtyard and atrium concepts are emerging as very
promising.
Wind-driven ventilation is one of the most basic and probably among the most
efficient ways to prevent overheating, and provide cooling in the summer season,
especially in humid climates. A review of previous works showed that little attention
has been given to the wind-driven natural ventilation capability of these structures, and
to the means of maximizing this ventilation. This study was thus aimed to fill part of the
gap in this subject.
In order to evaluate the wind-driven ventilation effectiveness of these structures,
and to examine some of the influential parameters, experimental wind tunnel tests were
made. Actual indoor air flows were measured in small replica models of four-storey
courtyard and atrium buildings by means of small calibrated orifice plates. A parametric
study of the geometry of the courtyard was made in isolation conditions, where the
depth and breadth of the courtyard were systematically varied. Several atrium
ventilation modes were tested both in isolation and in urban terrains. The tests involved
different roof geometries and various roof porosities. The measurements were followed
by a discussion on the validity of simple computational methods to predict airflow in
atria.
The investigation portrayed the importance of some factors, such as the wind
orientation rather than the courtyard geometry, for enhancing the flow in these
structures. The superiority of some atrium designs over the courtyard types, particularly
in sheltered sites, was underlined.
The study concluded with a discussion of design guide-lines and referred the
reader to an application as an example, describing a simple step-by-step method to
estimate the cooling benefits of these structures in a particular site, and making use of
the measurement data obtained from the study.