The development and modelling of a natural ventilation system for Indonesian conditions

Abstract

Natural ventilation is the preferred passive means of physiological cooling in warm humid climatic regions, which are characterized by high air temperatures, high air humidities and low air velocities. One of the more promising methods is the roof chimney system, which takes advantage of the abundant solar radiation of warm humid climatic regions to create a buoyancy driven ventilation. This thesis describes the development of a prototype roof chimney and its testing using both physical and computer modelling methods. Technical and non-technical problems were considered during the development of the prototype roof chimney. To check its feasibility, a preliminary calculation was done using a specially designed computer program. A research procedure was developed to reduce the possibility of experiment results bias caused by the climatic difference between the laboratory location (Wellington) and the case study location (warm humid climatic regions). Both physical and computer modelling experiments demonstrated that the prototype roof chimney could create air movement but only the former showed a sufficient air velocity to create physiological cooling. Even though they gave different magnitudes of air temperature and air velocity, the results from both experiments showed similar air temperature gradients, air velocity distribution and air flow pattern.