Compute shading coefficient from overhang geometry and orientation.
Key formulas: p.oh×Math.tan(p.alt×π÷180); min(1,proj÷p.wh)
| Item | Formula / Note | Source / Standard |
|---|---|---|
| SC and SHGC | SC = SHGC ÷ 0.87; SHGC is the total solar transmittance of the glazing | GB 50189-2015 Design Standard for Energy Efficiency of Public Buildings |
| Glazing combinations | IGU total SC combines layers weighted by incidence; Low-E coating position shifts ±5% | GB/T 2680-2021 Test Methods of Visible Transmittance for Building Glass |
| Internal shading | Curtains/blinds affect only indoor secondary heat; energy codes do not count them into glass SC | GB 50189-2015 explanatory notes |
| WWR limits | South windows with WWR >0.5 need SC ≤0.30; north ≤0.45 in hot-summer/warm-winter zone | JGJ 75-2012 Table 4.0.6 |
基于水平外遮阳板几何关系,结合太阳高度角与窗户朝向,估算遮阳板的遮挡率与综合遮阳系数,辅助建筑节能设计。