随机玻璃-聚合物混合超材料屋顶对南京夏季降温效应的模拟分析

Simulation Analysis of Cooling Effect of Randomized Glass-Polymer Hybrid Metamaterial Roof in Nanjing During Summer

为缓解南京夏季城市热环境危机,利用天气研究和预报模式(WRF),模拟了3类屋顶(普通屋顶、高反照率屋顶、随机玻璃-聚合物混合超材料屋顶)对南京夏季高温天气的影响。结果表明:(1)冷却屋顶(高反照率屋顶和随机玻璃-聚合物混合超材料屋顶)均可通过削弱到达城市表面的太阳辐射而使城市降温,随机玻璃-聚合物混合超材料屋顶白天平均降温为0.8~1.2℃,夜间平均降温为0.2~0.4℃,高反照率屋顶白天平均降温为0.6~0.8℃,夜间平均降温为0.2℃;(2)表面温度指数可表征冷却屋顶的热力性能,随机玻璃-聚合物混合超材料屋顶的表面温度指数为0.16~0.43,高反照率屋顶的表面温度指数为0.05~0.26,表明随机玻璃-聚合物混合超材料屋顶的冷却效果强于高反照率屋顶;(3)高反照率屋顶和随机玻璃-聚合物混合超材料屋顶分别能将36.7%和47.1%的太阳短波辐射返回到大气层,分别比普通屋顶少吸收19.6%和34.8%的热量。

To alleviate the crisis of urban thermal environment of Nanjing,the Weather Research and Forecasting Model(WRF)was uesd to simulate the effects of three types of roofs(conventional roof,high albedo roof and randomized glass-polymer hybrid metamaterial roof)during the extreme high temperature weather in Nanjing in 1-31 July 2017.The results showed that(1)cooling roofs(like high albedo roof and randomized glass-polymer hybrid metamaterial roof)can reduce the temperature of cities by weakening the solar radiation reaching the surface of the city.During the daytime,the average temperature of randomized glass-polymer hybrid metamaterial roof drops by 0.8-1.2℃,and the average temperature decreases 0.2-0.4℃in the nighttime.The average temperature of the high albedol roof drops by 0.6-0.8℃during the day and decreases 0.2℃at night.(2)The surface temperature index can be used to characterize the thermal performance of the cooling roof.The surface temperature index of the randomized glass-polymer hybrid metamaterial roof is 0.16-0.43.The surface temperature index of the high albedo roof is 0.05-0.26,indicating that the cooling effect of the randomized glass-polymer hybrid metamaterial roof is stronger than the high albedo roof.(3)The high albedo roof and the randomized glass-polymer hybrid metamaterial roof can return 36.7%and 47.1%of the solar short-wave radiation respectively.The atmosphere absorbs heat 19.6%less and 34.8%less than conventional roof.