دانلود رایگان مقاله اثر خارجی و داخلی اجزای سازنده و بازتابنده در روشنایی روز بین اتاقی

Abstract

Daylighting in a building residential area was simulated for different external ground reflectances and for various internal surfaces and window to wall areas. The simulations were run in software Velux Daylight Visualizer. Variations in internally and externally reflected components were studied for days of summer and winter solstice under clear and overcast sky conditions. These conditions were selected for two extreme cases for maximal and minimal daylight levels in the internal space during the annual evaluation. The purpose of the simulation study is to find differences in the room daylighting for different conditions than the traditional model of the overcast sky conditions and dark ground. It was found that the room illuminance levels for various interior and exterior reflectances can vary significantly for different sky models. This finding points on the importance of the climate based daylight evaluations.

3. Conclusion

The effect of externally and internally reflective components on interior daylighting was analyzed in this study. The simulations were completed to compare different sky conditions for the temperate climate region. The purpose of the simulation study is to show that the traditional method based on the most unfavourable conditions of the dark ground and overcast sky model is only convenient for small windows. It was proven that the ground reflectance importantly influences the internal visual conditions of common rooms. Indoor illuminance can be increased more that 45% in snowy regions compared the same building in the dark ground location. The internally reflected component influences daylight illuminance. The room daylit area of is increased from about 2–12% in case that wall reflectance of internal walls is changed from 0.3 to 0.5 or from 0.5 to 0.7, respectively. It also depends on the window size. It is mostly obvious for the clear sky conditions and big windows. It means that the room daylighting increases for more than fifty percent compared to variations with the smallest and biggest window. The room with small window has not uniformly distributed daylight on the working plane. There is a very low daylight level in the room depth compared to the illuminance level close to the window. The indoor illuminance is more uniform on the entire room area for larger window simulations. The room with small window (width 1.2 m) is poorly daylit under overcast sky. On the other hand very high illuminance in the room with the big window (width 2.4 m) is recommended to be reduced due to solar shadings to minimize possible glare problems in time of intensive solar shining. The design variation with the window of dimensions 1.8 m
1.5 m seems to be the most optimal solution for visual comfort in the reference room. Percentage of the daylit area for more than 300 lx also confirms that this variation is acceptable for common visual tasks.