An interface of night ventilation and mass structure for passive cooling design strategy in Ghadames traditional dwellings

The effectiveness of night ventilation strategy for residential buildings in the old town of Ghadames has been investigated in this study. Methods of field surveys including observations, temperature measurements and interviews were conducted to determine the characteristic building parameters and strategies including window patterns and space organisation that mostly contributed to achieve an efficient indoor comfort conditions especially at night summer time. Results showed that skylight openings can be a good window pattern for enhancing night ventilation in hot arid climate. Further findings indicated that majority of occupants tend to feel thermally satisfied with indoor air conditions particularly during daytime Due to high thermal mass structure in traditional dwellings indoor air gets warmer at night and small roof aperture would be not sufficient to readily extract warm air, so that a fixed roof fan is used to enhance air buoyancy. It is also observed that double ceiling height in the central hall plays an important role in balancing air change during day and night keeping interior at acceptable thermal conditions. The lower surface temperature due to standing wall to wall with surrounding buildings apparently has an impact on indoor thermal comfort conditions. However, the study suggested that new courtyard design in residential buildings should be considered taking into account all these passive design strategies in such a way to promote indoor climate conditions. Finally, and based on field surveys and measurements a preliminary design priorities and recommendations for passively ventilated dwellings in hot arid context are suggested.