Glare And Comfort Of Natural Lighting From The Roof

Nowadays,skylights are increasingly used in buildings,so more sunlight can enter the interior.Introducing sunlight into the interior can effectively reduce carbon emissions and improve the air quality of the living environment.Providing a comfortable and healthy light environment for the interior is an indispensable part of a good indoor environmental quality.This new energy-saving and environmentally friendly lighting method is gradually integrated into our lives.The research on roof lighting has gradually attracted everyone’s attention,but more scholars have focused on the application research of the outer structure of the sunroof,and little research has been done on glare and comfort.Uncomfortable glare can be unbearable sometimes,therefore,assessing the natural glare of a room is crucial in lighting design.Assessing the glare level in a room depends on glare indicators.There are many glare indicators now,such as UGR(Unified Glare Rating),DGI(Daylight Glare Index),DGP(Daylight Glare Probability)and many more,among these glare indicators,the most suitable indicator for evaluating daylight glare is DGP.DGP(Daylight Glare Probability)is a glare index system obtained from experiments based on natural light,Daysim and DIVA software have now incorporated the DGP model into the calculations to obtain an annual daytime glare distribution map.In this article,first build a DGP model of a room with a skylight using Rhino software,Import the Dalian meteorological file suitable for domestic use through the DIVA plug-in,calculate natural light glare throughout the year,and analyze the distribution of daylight glare throughout the year.Measured the middle hall of the library of Dalian University of Technology with Rhino software.The DGP model of the middle hall of the library of Dalian University of Technology was built with Rhino software.The Dalian weather file was imported through the DIVA plug-in to calculate the natural light glare throughout the year and the distribution of daylight glare throughout the year was analyzed.Through analysis and comparison of simulation experiments,the uncomfortable uncomfortable glare in Dalian is mainly distributed in January,February,November and December.Based on the simulation experiments,a questionnaire survey was conducted among the students reading in the library hall,the questionnaire is a survey of the comfort of students in the library’s hall,it is published online in the form of an electronic questionnaire through the system,the questionnaire was collected,and analyze the data that the light environment is considered to be caused by local over-brightness every month,it was concluded that the uncomfortable glare was mainly distributed in January,February,November and December.Therefore,it is verified that the results in the actual environment and the DGP model simulation environment are convergent.In order to effectively control the uncomfortable glare,the influence of the sunroof shape on the uncomfortable glare and the optimal direction of the sunshade grille to control the uncomfortable glare are studied.Create rectangular,square and circular skylights of the same area in the DGP model,import the weather file into the DIVA plug-in to calculate the annual glare,through analysis and comparison,it is concluded that the uncomfortable glare caused by the introduction of natural light into the rectangular skylight is small.On this basis,in order to effectively control the unbearable glare,a sunshade grille is added at the bottom of the skylight.Calculate the total amount of glare in the grid at different rotation angles in different directions throughout the year.Analyzing the comparative data,turning the grille southward can more effectively control the glare。This paper’s research work on roof lighting glare will provide technical support for future lighting design.