土壤含湿量对绿化屋顶隔热性能影响的数值研究

绿化屋顶因其特有的蒸发作用而展示出独特的隔热性能，其能力就如同给建筑增加了被动降温装置一样。本文用数值模拟的方法来分析土壤水分在绿化屋顶隔热系统中的作用，比较分析了间歇灌溉、连续灌溉和不灌溉三种模式下不同含湿量对屋顶传热的影响。研究得出：绿化屋顶隔热能力与土壤湿度呈正相关；采用间歇灌溉，屋顶热流密度对土壤湿度反应更敏感，在土壤含湿量不超过0．2时，随着湿度的增大，热流显著降低，在含湿量超过0．3后，热流反应较为迟钝；采用连续灌溉，屋顶的隔热性能较间歇灌溉提高3—4倍。

Numerical Evaluation of Influence of Soil Moisture on the Thermal Insulation of Green Roof

Green roofs, with special evaporation and good insulation performance, have the same capacity as passive cooling device of architecture. In this paper, the role of soil moisture in the insulation system of green roof was studied by numerical simulation. A comparison of influences of different moisture on roof heat transferring under three different modes of irrigation-intermittent irrigation, continuous irrigation and no irrigation was conducted. It＇s concluded that roof heat flux was negatively related to soil moisture, and the heat flux of roof was more sensitive to soil moisture in intermittent irrigation mode. When the content of soil moisture was less than 0.2, the heat flux decreased significantly while the humidity was increasing. When the moisture content was more than 0.3, the heat flux had a relatively slow reaction. It was in continuous irrigation mode that the heat insulation performance of roof improved 3-4 times than the performance in intermittent irrigation.