绿色屋顶的城市降温与建筑节能效果研究

绿色屋顶对建筑能耗的节能效果和对城市热岛效应的减缓作用得到大量案例研究的证实,但其推广进程却因为缺乏一般性的规律认识而受阻。对全球23个国家或地区的89项研究进行荟萃分析发现,绿色屋顶对建筑制冷的平均节能效果在30%左右,高于14%的平均供暖节能效果;对微气候的平均降温效果在2.9℃左右。节能效果方面,隔热良好的建筑反而阻隔了绿色屋顶蒸发蒸腾作用对建筑的冷却作用。保温层每增加1 cm,绿色屋顶的节能效果减少1%。微气候调节方面,气候类型、季节、植物类型均对降温效果有显著影响,影响幅度在1.4~3.1℃左右。研究结果可为宏观层面的模型模拟提供实证参数,为城市可持续发展与绿色屋顶的推广提供决策支持。

Research on the Urban Cooling and Energy Saving Effect of Green Roofs

An increasing nuhnber of case studies have proved that green roofs facilitate the energy saving of buildings and the mitigation of urban-heat-island effect.However,the lack of general information on the cooling effect hinders the larger-scale application of green roofs.This study synthesizes 89 studies from 23 countries and regions,and provides a general understanding of the effect of green roofs on building energy saving and micrioclimate amelioration.The results show that the average cooling-energy saving effect of green roof is 30%and the average heating-energy saving effect is 14%.The average cooling effect for microclimate of green roof is 2.9℃.As for energy saving effect,it is found that well insulated buildings hinder the cooling effect of evaporation and transpiration of green roofs.The energy saving effect of the green roof decreases by 1%for every 1cm increase of insulation layer.In terms of microclimate amelioration,climate,season and plant types has significant impacts on the cooling effect,varying from 1.4℃to 3.1℃.The findings provide empirical parameters for model simulation on macro level and generate policy implications for urban sustainable development and green roof installation.