Thermal comfort in traditional courtyard houses in Babul, Iran / Fatemeh Biabani Moghadam Baboli

Buildings account approximately 40% of the total annual energy consumption in Iran. It is therefore crucial to seek for means to reduce dependency of modern buildings on energy-consuming mechanical systems. The researchers believe that there is no better way to learn on passive design strategies than examining traditional architecture. This research focuses on a case study of Babul, an old commercial city, located in the Caspian Sea region. While many researchers have examined the potential of courtyard houses in hot-dry region in Iran, empirical data on the performance of courtyard houses in moderate climate region are few. Babul has many undocumented courtyard houses, and several are now under threat of being demolished. The study examined design characteristics of these houses and assessed thermal condition of the indoor and outdoor spaces through environmental measurement and occupants’ survey. The study documented several courtyard house configurations, applied with other passive design regimes, namely ivan, veranda, balcony, windows, and patio. During the assessment period the temperature inside the case study houses rose up to 30.2 C. The thermal assessment shows the residents rated their thermal environment as acceptable with acceptability rate of 90.3%. The most frequent actions taken by the residents to overcome thermal discomfort are by opening doors and windows, and making personal adjustment such as wearing light clothing and taking showers. Despite the cultural concerns for security and privacy, the residents of the houses regularly open their doors and windows throughout the day. In overall, 92.8% of the house inhabitants frequently change their living / family space according to the time of the year. When an indoor space was hot, they moved to the outdoor living space such as veranda, ivan and terrace. Houses investigated in this study represent not only the architectural style of those periods, but also the environmental tolerance of its inhabitants. The study reinforce the common knowledge that under the climate condition of moderate climate, passive design approach can result in a thermally comfortable houses, effectively achieved through incorporation of courtyards that encourage ample cross ventilation and shades.