U p w a r d – A i r f l o w V e n t i l a t i o n S y s t e m
761
UPWARD-AIRFLOW VENTILATION SYSTEM: AN
ARCHITECTURAL PROPOSAL FOR TROPICAL WEATHER
Jorge Isaac Perén Montero
1
Eduardo Toledo Santos
2
Brenda Chaves Coelho Leite³
1 2 3
Civil Engineering Department, School of Engineering of the University of São Paulo - USP, Brazil,
1
2
3
Abstract
An upward-airflow ventilation system for tropical houses is presented and the roof shape
is particularly analysed. A two-storey Panama Canal Zone House, located in the former
United States military facilities zone in Panamá city, was chosen for discussing and
presenting the potential of the upward-airflow ventilation system, which has the leeward
sawtooth roof and the naturally pressurized floor-plenum as components. Flexibility,
typical building shape, layout organization and the environment surrounding were
considered. The main architectural feature of a typical tropical house are described and
the layout organization, in which collective and common areas are at the ground level, is
considered favourable for the ventilation system here proposed. The upward-airflow
ventilation has the inlet opening at the lower level and the air outlet at the leeward roof
opening whereby the natural ventilation can be improved by inducing high differential
pressures between the lower and the higher levels surfaces. Computational fluid
dynamics (CFD) were used to analyse three sawtooth roof geometries and visualise the
air flow pattern inside and outside the simplified section of the typical tropical house. The
CFD simulation results highlighted the potential of the sawtooth roof geometry to induce
a high pressure coefficient module at the leeward outlet opening and increase the
efficiency of the upward-airflow ventilation system. Furthermore, the potential of the
naturally pressurized floor-plenum to complement the cross ventilation and also give
flexibility to the whole ventilation system were shown. Our aims is to recover the tropical
traditional architecture of Panama and to obtain energy-efficient home by adding a new
ventilation system strategy that can also be used in other developing countries. This
ventilation solution is useful for achieving thermal comfort by passive strategies and for
reducing power dependence, which is especially important for low-cost houses. The
ventilation system proposed has great potential to be implemented and especial
relevance in the actual context in which architecture plays a key role in reducing energy
consumption, reducing CO² emissions and pursuing healthy indoor environments.
Keywords:
Tropical house, energy-efficient home, envelope pressure coefficient,
flexible natural ventilation system, upward-airflow ventilation system, sawtooth roof,
prefabrication potential, architecture component, house design.
1. Introduction
Since the weather condition allows the use of passive strategies to achieve thermal
comfort, healthy environment and low energy consumption inside the house, natural
driving forces, such as wind and temperature difference, must be considered during the
whole house design process in order to guide the architecture components and the
shape of the house envelope.
When the wind force reaches the house envelope, a pressure gradient is generated in
the wall surfaces. A well conducted natural ventilation design process should take
advantage of this pressure difference to drive air through openings in the house. Thus,
the house shape is fundamental for increasing the pressure difference and for inducing
