Z E M C H 2 0 1 2 I n t e r n a t i o n a l C o n f e r e n c e
764
In tropical weather, the wind must be considered as a first-order design process variable
for developing the house envelope shape and the architecture components in order to
increase the pressure coefficient difference (∆ ) between the house surfaces.
Analysing the wind rose data is fundamental prior to the first conceptual design. The
pressure gradient can be induced by the building shape for moving the air throughout the
house from the positive pressure surface to the negative pressure surface opening.
1.2. Natural driving forces and architectural figures of the tropical house
Every architectural component has an impact on the natural ventilation efficiency and
requires special attention. Both architecture components and the whole house shape
must have integrated and common ventilation design criteria. The geometry effect was
analysed in the ventilation efficiency of some architecture components such as the slope
of the roof (Holmes 1994), larges eaves, pergola (Bittencourt 2006), ventilated parapet
(Bittencourt 2006) and height of wind catcher (Cândido et al. 2004). However, more
research is still necessary.
Taking advantage of the wind dynamic force to produce the pressure gradient necessary
to lead the air stream flow throughout the house and achieve efficient natural ventilation
is the main goal of this study. The most important components of a typical tropical house
are highlighted in figure 3. The effect of roof geometry will be presented in section 3.
Based on a Panama Canal House (Fig. 1), a simplified section of this typical tropical
house is analysed here, in order to illustrate the potential of the upward air flow system
and the associated roof geometry effect in natural ventilation efficiency. In the simplified
section, we just consider the roof geometry without the eaves and the screened porch.
The simplified geometry analysed in this paper is shown in figure 6. We also mean to
evaluate the other architecture component effects such as eaves, screened porch and
terrace-balcony in further studies.
Figure 5. Upward air flow system as an
alternative for cross ventilation – flexible
ventilation system
Figure 6. Section of typical tropical house showing
the section analysed and the floor with the
pressurized proposed (component of the upward-
airflow ventilation)
The geometry parameters in the current ventilation system analysis are the roof
geometry (three cases), the inlet opening location (two cases) and the wind speed (four
cases) as specified in section 2, Methodology.
