Traditional Javanese Residential Architecture Designs and Thermal Comfort. A Study Using a Computational Fluid Dynamics Program to Explore, Analyse, and Learn from the Traditional Designs for Thermal Comfort

Abstract

This thesis grows out of a desire to understand, in building science terms, the environmental features of traditional building design practices on Yogyakarta Special Region (Indonesia). The construction of traditional dwellings conforms to a set of rules, determining both the form and process of construction. The thesis describes tests of a number of factors related to traditional Javanese buildings for their effect on thermal comfort and air flow, isolating those design aspects and analysing them through contemporary techniques. Having proposed a scientific rationale behind traditional customs, two building styles, Joglo and Limasan are analysed. These styles are shown to relate to traditional numerological systems (petungan; i.e. sri and kitri), which have governed the specific details of domestic construction, and to the scale and siting of structures within the designated traditional guidelines. For comparison, simple hip-roofed dwelling (not applying Javanese style, petungan, and materials), representing current practices, were modelled. A commercial Computational Fluid Dynamics program was used as the principal research tool, testing thermal comfort through computer simulation. The main conclusion reached by this thesis is that traditionally designed Javanese architecture is thermally comfortable in a hot humid climate, more so than the simple hip-roofed dwelling. Literature studies reveal that modern building science ideas on thermal comfort in hot humid climates had been applied instinctively in traditional Javanese architecture. Computer simulation confirms them as thermally comfortable. Differences in style, petungan values, and scale were found to affect thermal comfort slightly, through their effects on the aerodynamic and thermal performance of the buildings. On the other hand, factors relating to materials have a significant effect on thermal comfort. The high porosity of traditional clay tile roof systems has provided Javanese buildings with a continuous ventilated roof, which is superior to corrugated steel from the point of view of ventilation of the dwellings. In addition, CFD modelling has proved to be a valid means of testing airflow within and around buildings. However, calibration is needed to ensure the CFD program performs accurately and reliably. Simplification of data input is also recommended to minimise complication in the simulation without necessarily sacrificing the accuracy of the results. Further applications and current limitations of CFD technology are discussed.