高反照率屋顶对城市热岛及空调能耗的影响

Effect of high-albedo roofs on urban heat island and air-conditioning energy consumption

为了研究高反照率屋顶这一城市降温技术对夏季城市热岛效应的缓解作用及对空调制冷负荷的影响,以夏季高温频发的杭州市为例,选取2017年7月22日—28日作为典型高温时段,采用中尺度天气预报模式(WRF)耦合考虑建筑物能量交换的多层城市冠层参数化方案(BEP+BEM)进行数值模拟.结果表明,反照率为0.85的屋顶使城市区域日均降温0.37℃,城市热岛强度减小0.21℃,城市热岛效应得到了一定程度的缓解,空调制冷负荷降低约5.3%;建筑物密集的商业区的降温和节能效果均优于低密度居住区;屋顶反照率与城区2 m气温及空调能耗均线性负相关.

The city of Hangzhou,where high temperature occurred frequently in summer,was selected as a typical high-temperature period of 22—28 July 2017 in order to analyze the mitigation effects of the high-albedo roofs,the urban cooling technology,on the urban heat island in summer and its impact on the cooling load of air-conditioning.The numerical simulation was performed using the weather research and forecasting model(WRF),coupled with the building energy model based on multi-layer building environment parameterization(BEP+BEM).Results show that the roofs with an albedo of 0.85 can reduce the average daily temperature of the urban area by 0.37℃,while the urban heat island intensity decreases by 0.21℃.The urban heat island is alleviated to some extent,and the airconditioning refrigeration load is reduced by about 5.3%.High-albedo roofs show better cooling and energy-saving effects in buildings-intensive business districts than in low-density residential areas.The roof albedo is negatively correlated with the urban 2 m temperature and air-conditioning energy consumption.