Optimization Study On Daylight Environment Of Primary And Middle School Classrooms With Side-light Based On Visual Comfort

With the continuous advancement of technology,artificial lighting technology has also developed rapidly,bringing about huge changes in lighting conditions.But the incidence of myopia has also increased rapidly.What is particularly serious is that the myopia rate of primary and middle school students continues to rise,and the detection rate of poor eyesight in younger students is more significant.Student myopia has become a major issue related to the future of the nation and the country.As the main learning place of students,the quality of the light environment in the classroom will not only directly affect the students’ vision health,but also affect their learning efficiency and circadian rhythm.Classroom light mainly comes from artificial lighting and daylighting.daylight has incomparable advantages over artificial light.However,most classrooms in our country use side windows for lighting,which is easy to cause uneven illumination and glare,which leads teachers and students to close the curtains and turn on the artificial light,which consumes a lot of electricity and has low effective utilization of daylight.Therefore,it is of great significance to study how to optimize the daylighting environment of classrooms.Through the methods of literature reading,current situation investigation and numerical simulation,this paper takes the classrooms of primary and middle schools in South China as the research object,aiming at visual comfort,to optimize the lighting of classroom with sidelight.The research content and results are as follows:1)Through the investigation of the current situation of light environment in primary and middle school classrooms in South China,it can be seen that most of the primary and middle school classrooms in South China use single exterior corridors for double-sided daylighting,most of which face north and south,with large windows,and the total window-to-ground area ratio is about 0.24～0.35.The shading measures on the facade of the building are not in place,and the current classroom daylight environment has problems of uneven illumination and glare,especially in the north exterior corridor and south daylighting classrooms,which are also the main factors affecting students’ satisfaction with the classroom daylight environment.2)Simulation of the initial daylight environment of a typical classroom model,the results show that the VG1 viewpoint on the left side of the blackboard near the south side window has the most serious glare,and the glare above the perceptible level(DGP ≥0.35)is the whole year.The proportion reached 60.47%,of which intolerable(DGP ≥0.45)glare time accounted for 34.63%.Based on the DGP,it is proposed to evaluate the glare status of classrooms by "the most unfavorable viewpoint VG1,the time proportion and time distribution of various degrees of glare throughout the year.3)Optimizing and studying the lighting of the side windows of the classroom from the two aspects of window glass material properties and shading design.The results show that increasing the transmittance of the glass will aggravate the excessive daylighting of the southfacing windows,which can make the ratio difference of the proportion of glare time above the perceptible level of VG1 viewpoint as high as 33%.Setting shading on the window can effectively improve the light environment of the classroom.In the traditional panel shading,the effect of comprehensive shading is the best,and the length of the sunshade is an important factor affecting its effect,the best length is 1.6m-1.8m,and the proportion of glare time above the perceptible level of the corresponding VG1 viewpoint is reduced to 1.56%;the improvement effect of the reflector on glare is better than that of the comprehensive shading,its installation height should be 2m-2.4m,and the optimal shading length is 1.4m-1.6m,it is meaningless to continue to increase after the built-in plate is up to 0.5m.The proportion of glare time above the perceptible level of VG1 viewpoint is always maintained at about 19%;the louver external sunshade has a better control effect on glare,and the blade size of the louver has little effect on its shading effect,while the deflection angle is key to its effect.The best deflection angle is 45° to 60°,At this time,the proportion of glare time above perceptible level of VG1 viewpoint can be controlled below 3%.This research explores the main problems of the current classroom light environment through the current situation investigation,understands the factors affecting students’ satisfaction with the light environment,and then uses numerical simulation to study the optimization strategy of classroom side window lighting,in order to improve the classroom light environment,reduce students’ myopia rate,and save lighting Energy consumption provides theoretical guidance.