Numerical Investigation of the Effects of Different Influencing Factors on Thermal Performance of Naturally Ventilated Roof

Ventilated roof can improve the thermal performance and reduce energy consumption of building roofs. In order to determine the optimal design parameters and adaptability of naturally ventilated roofs, this paper conducted numerical investigations of the effects of different influencing factors on thermal performance of naturally ventilated roof. Three field coupling numerical simulation method of temperature field, flow field, and solar radiation field is used in this paper to improve the simulation accuracy. The research results show the optimal air gap layer thickness in naturally ventilated roof increase with the increase of roof length, which wasn't considered in previous studies. The peak interior surface temperature of ventilated roof increase with the increase of outdoor atmospheric pressure. The ventilated roofs with the 30% ~ 40% roof slope have stronger stack effect and the better ability of discharging solar heat gains than the other roof slopes. The phase change material can increase potential energy saving of roofs through using the nightly free cooling. The small roof damage hole in the upper roof will not reduce the thermal performance of ventilated roofs apparently. The results can provide beneficial suggestions for guiding the design optimization and evaluating the energy-saving effect of the naturally ventilated roofs.