Dynamic Analysis for Daylight Availability in High-Density Urban Area 高密度城市区域动态采光分析

1. Dynamic Analysis for Daylight Availability in High-Density Urban Area 高密度城市区域动态采光分析 杜 江 涛 Jiangtao Du (PhD student) Architecture School University of Sheffield

2. ABSTRACT This study describes a dynamic analysis method to investigate daylight availability in high-density urban area. In contrast to traditional static concept based on Daylight Factor, this method introduces Daylight Coefficient and Perez sky luminance function, which can be used to dynamically analysize the annual daylight level profile. Daylight Coefficient on the outside surfaces of buildings has been calculated by DaySim, a package using Radiance algorithm. Also, Sky Luminance Distribution comes from annual solar gains through Perez’s sky model function. Accordingly, integrating Daylight Coefficient and sky luminance distribution would get illuminace values across the outside surfaces. The annual illuminance profile of there surfaces is a significant indicator for daylight levels in buildings. Three typical built layouts in current high-density Chinese city have been modelled and simulated. The solar radiation data in the simulation are derived from the weather file (2005) of Beijing and Shanghai, which represent different weather zones (II and III) in China and both have plenty of high-density lots. The proposed methodology can help urban and building designers evaluate the possibilities of using natural lighting in high-density area from the early conceptual design stages.

3. INTRODUCTION • Natural Light Availability and Performance component: skylight and sunlight. benefit: reducing artificial light; saving energy; improve indoor qualities (psychology). • High-density Urban Area important environmental issue: daylit spaces; building type: residential buildings; commercial buildings. • Daylight and Sunlight code in China [1,2] GB/T 50033-----2001 Standard for daylighting design of buildings 建筑采光设计标准 GB 50180-----93 (2002) Code of urban residential areas planning & design 城市居住区规划设计规范

4. GB/T 50033-----2001 Standard for daylighting design of buildings 建筑采光设计标准 [1] GB 50180-----93 (2002) Code of urban residential areas planning & design 城市居住区规划设计规范 [2] 光气候分区：五类区域 采光系数 (DF)：居住建筑 1% 办公建筑 2% 建筑气候分区：七个区域 日照标准：居住建筑 大寒日 或者 冬至日 日照时数 • Static method for daylighting controlling in buildings, simple; • Easily adopted, but not corresponding to the real climate conditions and urban layout; • Low practical feasibility and lacking flexibility. Climate-based Dynamic model or method [3]

5. METHODOLOGY • Climate-based Dynamic model ---- Daylight Coefficient and Perez sky model Daylight Coefficient Peter Tregeza [4] [5] [5] [6] 145 patches

6. Perez sky model [7, 8] R. Perez, R. Seals, J. Michalsky; All-weather model for sky luminance distribution — preliminary configuration and validation Solar Energy 50 3 1993 235–245. R. Perez, P. Ineichen, R. Seals, J. Michalsky, R. Stewart; Modeling daylight availability and irradiance components from direct and global irradiance Solar Energy 44 5 1990 271–289. • Three ways to produce the luminance distribution of sky: • Direct radiation, diffuse radiation • Global illminance, diffuse illuminance • Coefficients setting: a,b,c,d,e [5] Sky luminance DC E

7. Climate-basedDynamic method for urban daylight availability analysis • Typical positions on the Vertical surface of building • Daylight Coefficient of reference positions • Weather data of test reference year (TRY) • Annual illuminance profile (5 minutes, 10 minutes, 0.5 hour, 1 hour) [9]

8. Case analysis for daylight availability analysis in high-density urban area 1. Linear layout Higher position Middle position Lower position 2. Court layout Beijing: II 寒冷地区 III 光气候区 Shanghai: III 夏热冬冷地区 IV 光气候区 3. Dot layout [1, 2] north

9. RESULTS Day: 20/01 (大寒） 20/03 (春分） 21/06 (夏至） 23/09 (秋分） 22/12 (冬至） Step: 1 hour Beijing 1-20

10. Beijing 3-20 6-21 9-23 12-22

11. Shanghai 1-20

12. Shanghai 3-20 6-21 9-23 12-22

13. Beijing 1-20

14. Beijing 3-20 6-21 9-23 12-22

15. Shanghai 1-20

16. Shanghai 3-20 6-21 9-23 12-22

17. Beijing 1-20

18. Beijing 3-20 6-21 9-23 12-22

19. Shanghai 1-20

20. Shanghai 3-20 6-21 12-22 9-23

21. CONCLUSIONS • A real dynamic method for daylight availability investigation; based on the weather data (radiation); • Illuminace output, easily to understand and compile; • Based on DC and Radiance algorithm (DaySim), suitable for complicated environment; • More knowledge needed when using the tool; long running time; thousands of data.

22. REFERENCES 1. GB/T 50033-----2001 Standard for daylighting design of buildings 建筑采光设计标准 2. GB 50180-----93 (2002) Code of urban residential areas planning & design 城市居住区规划设计规范 3. BS 8206-2:2008 Lighting for buildings – Part 2: Code of practice for daylighting 4. 1. P R. Tregenza, M I. Waters; Daylight Coefficients.Lighting research and technology 15 2 1983 65–71. 5. J.Mardaljevic; Daylight Simulation: Validation, Sky Models and Daylight Coefficients. PhD Thesis 2000 De Moutfort University. 6. C. Reinhart, S. Herkel; The simulation of annual daylight illuminace distributions – a state-of-art comparison of six Radiance-based method. Energy and Buildings 32 2000 167–187. 7. R. Perez, R. Seals, J. Michalsky; All-weather model for sky luminance distribution — preliminary configuration and validation Solar Energy 50 3 1993 235–245. 8. R. Perez, P. Ineichen, R. Seals, J. Michalsky, R. Stewart; Modeling daylight availability and irradiance components from direct and global irradiance. Solar Energy 44 5 1990 271–289. 9. C. Reinhart, O. Walkenhorst; Validation of dynamic Raidance-based daylight simulations for a test office with external blinds. Energy and Buildings 33 2001 683–697.