使用BSDF数据的教室黑板面反射眩光模拟分析

Simulation Analysis of Reflection Glare Within the Blackboard of Classrooms Using BSDF Data

黑板面上出现的反射眩光是导致教室中视觉不舒适的主因,反射眩光可通过粉笔字与黑板的亮度对比度衡量,本文的目的在于提出基于亮度对比度来分析教室黑板面上反射眩光的方法。本文建立了教室主要使用场景反射眩光分析模型用于评价不同采光方案的反射眩光干扰度,在进行复杂采光系统模拟时使用了双向散射分布函数数据,文中介绍了BSDF并进行了准确度验证。结果显示:所提出的优化采光方案所对应的黑板面内的对比度(C≥1.3占比)高于基础方案27%,显著降低了教室内黑板面上反射眩光干扰度。本研究结论为:1)BSDF数据用于模拟教室采光系统准确度高于传统采光模拟方法;2)以黑板范围内的亮度对比度为基础建立的指标用于评估教室采光方案具有可行性;3)分析教室采光设计时,同时满足黑板面内亮度对比度和课桌面照度是提升视觉舒适度和天然光利用率的有效方法;4)用遮阳板将窗分为上下两个部分,上部分采用光线偏转装置有助于降低黑板面内眩光干扰度。

The occurrence of reflected glare on the blackboard is the main cause of visual discomfort in the classrooms,the influence scale of reflected glare can be evaluated by the luminance contrast between chalk writings and blackboard.This paper intended to propose a contrast-based analysis method to study the level of glare interference in classrooms.A study model was established to evaluate the reflected glare level of various fenestration systems,and BSDF data was employed in the simulation process of a complex fenestration system(CFS).BSDF was introduced and the accuracy was validated in this paper.The results indicated that the contrast within the blackboard(the percentage of C≥1.3)of the optimized daylighting design scheme was 27%higher than that of the fundamental scheme,reducing the level of glare interference significantly.The conclusions of this study are 1)the accuracy of daylight simulation of the fenestration system in the classroom using BSDF data is higher than the traditional method;2)Luminance contrast within blackboard based index is practicable to rate the daylight design scheme of classrooms;3)To meet the requirements both from luminance contrast within the blackboard and the luminance on desks is an effective method to ensure visual comfort and daylight availability when analyzing the daylighting design of classrooms;4)It is helpful to reduce the level of glare interference within blackboard while a window was divided into upper and lower parts by a shading panel and the light redirection facility was employed in the upper part.