Climatic Performance of Traditional Houses in the Old Texture of Shiraz using the Thermal Comfort ApproachCase Study: the Iwan (Veranda)

A fundamental look at the habitats and environment-friendly spaces of the past confirms that climatic sustainability was one of the main features of traditional houses. In the past, humans learned to adopt different strategies to improve the thermal performance of their living spaces, i.e., by creating intermediate spaces between open and closed spaces they were able to control indoor temperatures. The main function of verandas was climatic, which by means of shading play an important role in controlling indoor temperatures and creating thermal comfort. One of the main objectives of this paper is to study the climatic data and thermal performance of verandas with respect to their physical proportions. Three traditional buildings having verandas were selected at different geographical locations. The field climate data was collected using measuring instruments such as a thermo-pyrometer and a thermo-hygrometer and then validated using Envi-met and Bio-met simulation software to measure the PET thermal comfort index. The climatic data was weighted using correlation coefficients. Despite all correlating physical aspects of the courtyards, such as area, vegetation, pond, wall height and materials, it was observed that the reduction of the average radiant temperature in the courtyards and verandas improved thermal performances. There was a strong correlation observed between the average radiant temperature and the thermal comfort index in the three houses. Increase of the width of the veranda, increase of their facade opening area, increase of their elevation from the courtyard level, and increase in shading of the courtyard areas are the most effective factors improving the PET index and consequently reducing thermal stress. The resulting guidelines from this research will open a new window to retrieve the concepts of ancient patterns to help solve urban climatic problems.