Energy consumption and visual comfort are issues worthy of concerning in the teaching buildings. To improve the light and thermal environment in the classroom, structural dimension parameters of shading system are optimized by the multi-objective genetic algorithm based on the lighting, energy consumption, and visual comfort in this study. The 3D parametric modeling of the classroom is performed by using the Grasshopper and Rhino software, and the quantitative impact of the integrated external sunshade and perforated external shading panel on the lighting, air conditioning and heating energy consumption, and visual comfort of the classroom are analyzed by the Radiance, Daysim, and EnergyPlus calculation engines. Subsequently, the optimal structural dimensions of the composite shading system in the east, west, south, and north orientations in Nanchang area are determined.

The optimized results show that the optimal dimensions (width of the vertical shading board W; overhang length of the horizontal shading board L) of the integrated external shading boards in the east, west, south, and north orientations for the established classroom model are (0.3; 1.8), (0.6; 1.2), (0.4; 0.8), and (0.5; 0.7), respectively, as well as the optimal structural dimensions of the perforated shading panels (perforated panel to window ratio – perforation percentage – holes arrangement) are 71.5%–30%–crossing arrangement, 70%–50%–crossing arrangement, 90%–30%–crossing arrangement, and 65.6%–70%–matrix arrangement, respectively. It is found that total annual energy use intensity is reduced by 4.5% to 18.8%, the lighting quality in the near-window region (region I) is improved by 25% to 37%, the visual comfort in the classroom is improved by more than 30%, and the solar irradiance of the window is reduced by at least 27%. The proposed design approach of the classroom external shading system can not only greatly improve indoor lighting quality and visual comfort but also reduce total annual energy use intensity.

能耗和视觉舒适度是教学楼值得关注的问题。为改善教室光热环境，本研究基于光照、能耗、视觉舒适度等因素，采用多目标遗传算法对遮阳系统的结构尺寸参数进行优化。利用 Grasshopper 和 Rhino 软件对教室进行 3D 参数化建模，分析了一体化外遮阳和穿孔外遮阳板对教室照明、空调和供暖能耗以及视觉舒适度的影响。通过 Radiance、Daysim 和 EnergyPlus 计算引擎。随后，确定了东、西、南、复合遮阳系统的最优结构尺寸，

优化结果表明，所建教室模型东、西、南、北方向的综合外遮阳板的最佳尺寸（垂直遮阳板宽度W；水平遮阳板悬垂长度L）为（分别为0.3；1.8）、（0.6；1.2）、（0.4；0.8）、（0.5；0.7），以及穿孔遮阳板的最佳结构尺寸（穿孔板与窗的比例-穿孔百分比-孔排列） ) 分别为 71.5%-30%-交叉排列、70%-50%-交叉排列、90%-30%-交叉排列和 65.6%-70%-矩阵排列。研究发现，全年总能源使用强度降低 4.5% 至 18.8%，近窗区域（I 区）照明质量提高 25% 至 37%，教室视觉舒适度提高30%以上，窗户的太阳辐照度降低至少27%。所提出的教室外遮阳系统的设计方法不仅可以大大提高室内照明质量和视觉舒适度，还可以降低年总能源使用强度。