Effects of sea-breeze natural ventilation on thermal comfort in low-rise buildings with diverse atrium roof shapes in BWh regions

The purpose of this study is to evaluate the effects of the atrium ceiling on catching sea breeze, indoor thermal comfort, and natural ventilation in the buildings in coastal areas with BWh climate during warm seasons. This study was further sought to forerun the internal thermal comfort through Fanger's theory considering environmental and turbulence parameters in atrium-roofed low-rise buildings in BWh coastal areas, assuming that the results would be practical for engineers and designers in BWh onshore regions. To achieve these purposes, 12 atrium ceiling shapes have been studied in a three-story building in Bushehr (Iran) with BWh climate. Specimens were simulated in Ansys Fluent for 2:00 p.m. on 29th July as the hottest day of the year. The experimental data of wind tunnels have been employed to validate the results, with an observed 1.5% difference between CFD and experimental findings that confirm the validity of the data simulated. Specimen #12 which has a cube-shaped roof with a blade with distance on atrium output to create air pressure difference had the highest volumetric flow rate from the atrium outlet (2 m3 s−1) and the best condition in terms of natural ventilation. In addition, specimens #12 and #3 which has a cube-shaped form, and the atrium outlet was placed on the roof maintained the best performance in terms of thermal comfort than other specimens, with PMV values of 2.6 and 2.4, respectively. Furthermore, the PMV values are correlated with air velocity (r = 0.61), dry temperature (r = 0.72) and air pressure (r = 0.52) as the environmental parameters. The correlation coefficient has been calculated between PMV and Ti (r = 0.61), Tke (r = 0.45), and Tdf (r = 0.37). PPD had a substantial correlation with velocity (r = 0.71), temperature (r = 0.6) and air pressure (r = 0.45). Furthermore, the highest correlation coefficient has been observed between PPD and Ti (r = 0.54) and Tke (r = 0.37), and the least correlation has been seen between PMV and Tdf as r value equals 0.27.