动态采光指标分析与侧窗采光范围

An analysis of dynamic daylight performance metrics & the daylight availability of side-lit windows

为指明动态采光指标的先进性并倡导在建筑采光设计案例中应用动态指标进行分析,首先,通过理论分析说明在评价天然光表现时动态采光指标较之静态指标(采光系数)更为合理;进而,以广州的天气数据为计算条件,基于Daysim动态采光模拟结果,使用DF/DA/UDI指标针对4种不同立面类型进行了采光效果排序并与基于采光系数的排序结果进行比较,结果说明了动态采光指标在方案择优方面的优越性.此外,分析了不同窗墙比、遮阳悬挑尺寸建筑立面的有效采光范围与眩光出现概率,相关结果可纳为设计指导.研究结果表明:采光系数用于评价建筑采光存在不足,推荐在建筑采光分析中使用动态采光指标;将DA指标值不低于DA_300 lx[50%]的范围定义为有效采光区域,该量值可以较好地反映侧窗采光的有效范围.

The aim of this topic is to indicate the advantages of dynamic daylight performance metrics and advocate the acceptance of dynamic metrics in analysis of building daylight design cases.Firstly,this paper indicates that the dynamic metrics are more reasonable than statistic metrics(daylight factor) in evaluating the daylight environment via theoretical analysis.Then taking the weather data in Guangzhou as the calculation input,based on Daysim simulation results,the depth of daylight available area is defined by DA metric.Under the regional weather condition in Guangzhou,based on Daysim dynamic daylight simulation data,the daylight performance of 4 facade types is ranked via metrics DF/DA/UDI and compared with that ranked by daylight factor,and the result indicates the superiority of dynamic metrics in selecting the optimal design schemes.Furthermore,the daylight available area and probability of glare occurrence towards facades with various WWR and shading overhang size are analyzed,and the results can be adopted as design references which suggest that the dynamic metrics should be used to evaluate daylight performance and the areas where DA metric values are no less than DA_300 lx[50%]should be defined as daylight available area that could indicate the availability of side-lit windows well.