不同冷却屋顶对城市街区热环境的影响模拟

Simulation of the Impacts of Different Cooling Roofs on the Thermal Environment of Urban Blocks

当前采用何种冷却屋顶材料缓解城市化带来的高热灾害是城市气象领域的热点问题。本文基于城镇能量平衡模式(TEB),分析了4种不同材料的冷却屋顶,包括转化效率为14%的太阳能板(覆盖面积分别占屋顶面积的100%及50%)和3种高反照率材料:铝箔沥青膜、白色TPO膜、科罗拉多大学新研发的玻璃聚合物混合超材料,在2017年夏季高温热浪时间段(7月16~30日)对建筑物街区屋顶表面温度及辐射热量产生的影响。结果表明在持续高温的天气背景下,在屋顶铺设超材料和100%覆盖面积的太阳能板降温效果最好,屋顶表面温度白天平均分别可降低18.59 K和19.58 K,铝箔沥青膜效果次之,平均降低13.47 K,50%覆盖面积的太阳能板TPO膜再次,平均降低9.7 K和5.4 K,夜间也具有1.08~4.53 K的降温。铺设冷却屋顶材料可以直接或间接地减少冷却能源需求,铺设100%太阳能板以及超材料屋顶可以使建筑物冷却能耗降到最低,每平方米分别至多可降低2.1 W m~(-2)和2.16 W m~(-2),使用铝箔沥青膜效果次之,至多降低1.47 W m~(-2),50%铺设面积的太阳能屋顶及TPO膜再次。其中所选太阳能光伏板每日可额外产生最多1.84 kW h的电量,模拟的两周内产生电量可全部抵消同期空调制冷能耗。

The use of cooling roofing materials to alleviate the effects of urban heat islands and the energy crises brought by urbanization has always been a critical research issue in the field of urban meteorology.This paper used offline town energy balance mode(TEB)to analyze roof surface temperature and the radiant heat of urban blocks during the two-weeklong heatwave during 16−30 July 2017.The study involved solar panels with a conversion efficiency of 14%and three kinds of high albedo roof materials:Aluminum foil asphalt membrane,white TPO membrane,and randomized glasspolymer hybrid metamaterial from the University of Colorado.The results show that under continuous high temperature,the super-material roof treatment and the 100%coverage of roof area with solar panels treatment had the best cooling effect,reducing daytime roof surface temperature by 18.59 K and 19.58 K,respectively.The aluminum foil asphalt membrane’s effect takes second place,reducing temperatures by 13.47 K on average.The TPO film and covering 50%of the roof area with solar panels had the worst performance,it also has a nighttime cooling effect of 1.08–4.53 K.The setting of cooling roofing materials can reduce cooling energy demand both directly and indirectly.Covering 100%of the roof area with solar panels and using super-material roofs can minimize buildings’cooling energy consumption,and can reduce 2.1 W m−2 and 2.16 W m−2 per square meter,respectively.Aluminum foil asphalt film takes second place,with a reduction of 1.47 W m−2.TPO film and 50%solar panel coverage had the smallest effect.The selected solar photovoltaic panels can generate an additional 1.84 kW h of electricity per day,and the electricity over the simulated two weeks can offset all the energy consumption of air conditioning during the same period.