Thermal performance of domed roof in air-conditioned spaces

Abstract

Due to their thermal performance, domed roofs are one of the passive solutions that affect energy consumption in buildings. The thermal performance of domed roofs has been investigated in many naturally ventilated spaces. However, few studies have discussed their performance in conditioned spaces. Therefore, this study introduces a computational comparison between domed and flat roofs to investigate their impact on thermal comfort inside a conditioned mosque. At an earlier stage, field measurements were carried out inside a Bahraini mosque to acquire its indoor air conditions during the summer period of 2021, in addition to validating the computational model. The findings of this study confirm that, under mechanical cooling conditions, the flat roof offers a lower indoor temperature than the domed roof by 0.4 °C and 0.1 °C for open and closed doors, respectively. Similarly, the air velocity is lower by approximately 0.01 m/s for both door modes. The overall PMV values of the flat roof are also lower by 0.07 and 0.01, while the PPD values are lower by 0.20, and 0.34 for open and closed doors, respectively. Based on these small differences, it can be concluded that the thermal performance of both roofing systems behaves equally in conditioned spaces. However, the air patterns are substantially different, the overall thermal performance is similar. This similarity drives building designers to rethink the thermal performance of the domed roofs in air-conditioned spaces with such a hot climate, regardless of their aesthetic and acoustical behaviour.

Keywords

• Thermal comfort
• Computational fluid dynamics (CFD)
• Predicted mean vote (PMV) and predicted percentage dissatisfied (PPD)
• Domed roof
• Flat roof