基于ENVI-met模拟的屋顶绿化热环境影响

Thermal Environment Effects of Green Roofs Based on ENVI-met Simulation

文章以同济大学四平路校区为研究对象,采用ENVI-met 4.4.2模拟4种方案(无绿化、地面绿化、屋顶绿化、地面绿化与屋顶绿化的组合绿化)时校园内温度分布特征,对比分析有地面绿化和无地面绿化情况下,7∶00、12∶00、20∶00、1∶00时屋顶绿化对室外行人高度(1.5m)和屋面高度(12.5m、17.5m)的气温影响。结果表明:(1)校园无地面绿化时,屋顶绿化的降温效果较为微弱;(2)校园有地面绿化时,屋顶绿化对环境气温的影响明显增强,尤其是行人高度的温度变化明显增大,且随着高度增加,影响逐渐减弱;(3)校园有地面绿化时,12∶00时屋顶绿化对建筑较少的开放区域降温效果明显好于建筑密度大的区域,而7∶00、20∶00和1∶00时开放区域会出现升温现象。屋顶绿化除增加绿化总量外,也增加了绿色空间的连接性,有利于形成联系更为紧密的绿色空间网络,提高开放空间的热舒适性。

Taking the Siping Road Campus of Tongji University as the research object,the paper simulates the temperature distribution characteristics in the campus using ENVI-met 4. 4. 2 under four scenarios( no greening,ground greening,roof greening,and both ground and roof greening). The effects of roof greening at the outdoor pedestrian height( 1. 5 m) and roof height( 12. 5 m and 17. 5 m) on temperature at 7 ∶ 00 am,12 ∶ 00 am,20 ∶ 00 pm and 1 ∶ 00 am under the scenarios of having ground greening and having no ground greening are compared and analyzed. The results find that: (1) The cooling effect of roof green is not obvious when ground greening is absent;(2)In the case that there is ground greening,roof green has enhanced influence on the ambient temperature,especially the temperature at outdoor pedestrian height which changes obviously,and the influence is gradually weak with the increase of height;and (3) When there is ground greening in campus,the cooling effect of green roof on the open area with less buildings at 12 ∶ 00 is significantly better than that in the area with high building density,while the temperature of the open area will go up at 7 ∶ 00 am,20 ∶ 00 pm and 1 ∶ 00 am. In addition to increasing the total amount of greening,roof greening also increases the connectivity of green spaces,which is conducive to the formation of a more closely connected green space network and improve the thermal comfort of open spaces.