The contribution of elevated floor systems to the environmental performance of houses in warm humid regions

Abstract

The purpose of this study was to investigate the contribution of elevated floors to the environmental performance of houses in hot-humid regions. Elevated floor systems have long been applied in traditional houses in wet tropical regions; they are valued for improving indoor climate comfort without consuming energy. The common belief is that elevated floor systems improve indoor comfort in two ways: a) raise the house so that it can be exposed to wind and b) create a cooling effect for the floors. This research evaluated both theories and sought for others. It is hoped that by understanding the performance of elevated floor systems, they can be applied properly to modern conditions. The research not only discusses the elevated floor systems themselves but also the standards used to evaluate them. Careful steps was taken to avoid any misleading results caused by applying improper standards. The intent was not to correct existing standards but rather to put them in their correct perspective. When discussing traditional houses with elevated floors, the research referred to the available standards carefully, and always paid attention to any possible different conditions, such as the preference of people traditionally to be bare breasted, or wear very light clothes. It was a great surprise to find (from the scenarios imitating past environment conditions) that people can experience comfortable indoor condition even without elevated floor systems. The research produced two important conclusions which, though they appeared to contradict each other, they indicated that elevated floor systems improve indoor climate comfort. The water table experiments showed a jet effect occurred under the floor. This resulted in negative pressure area, which (in reality), would suck the air out and generate ventilation. In warm humid regions (where humidity causes unpleasantness) this phenomenon is beneficial. Mathematical modelling also indicated that elevated floor systems contributed to the indoor climate comfort. According to these simulations, a house with an elevated floor would experience higher indoor air velocities, more air changes, and enable its occupants release their body heat more easily. These effects correspond to the increase of its floor height. All of them have been expressed in three new formulae developed from available formulae. The research also has made recommendations for further research projects. It has found that elevated floor systems were not a simple phenomenon. Even though research only emphasized in physical factors, the research process the research found so many variables that made impossible to cover up. Research projects using more sophisticated equipments and more precise models are required to explore the full potential of elevated floor systems and to modify them so that they are applicable for modern conditions.