The Research Of Side Daylighting Of Office Buildings Based On Dynamic Daylighting Evaluation And Simulation

The effective daylighting is very important for the energy saving of officebuildings. The characteristics of window are important factors that affect the qualityof daylighting, which including: orientation, size, shape, light transmittance, locationand so on. The conventional static daylight performance metrics can’t reflect the realcondition of daylighting and can’t led to a superior daylighting design, just because oftheir own limitations. Dynamic daylight performance metrics are the developmenttendency of international research on daylighting. There are a series of dynamicperformance metrics. Compared to static daylight performance metrics, dynamicmetrics consider the diversification of sky types, orientation of buildings, location,and the application of auxiliary lighting system. They can give designers a morerealistic reflection of indoor daylighting conditions. Therefore, this study appliesdynamic daylight performance metrics to evaluate and analyses the side daylighting ofoffice buildings.First of all, through the practical investigation of daylighting conditions of15office buildings in Beijing and Tianjin, the writer find that offices widely use sidewindows to lighting. The side daylighting always brings some problems, such as poorillumination uniformity and glare nearby the window. The survey find that97%ofoffice spaces use curtains to solve these problems, but causing the waste of energyand the problem of “open lights with the curtain are closing”.In order to validate the reliability of the simulation software Radiance, the studycompared the measured indoor illumination value of office709of Northern ScienceBuilding in Tianjin University and the simulated data from Radiance. The Mean BiasError of simulation result is7.94%, the Root Mean Square Error is18.2%. Theseresults illustrate that the using of Radiance in this paper has a high accuracy, and laythe foundation for using the dynamic simulation software Daysim.Then the writer simulates the daylighting conditions of the same room withdifferent orientations and geographical locations by using software Radiance andDaysim. The comparison and analysis show that: the dynamic daylight performancemetrics play a better role in reflecting the status of indoor daylighting. To solve the daylighting problems existing in office spaces, the writer make aresearch on different auxiliary daylighting systems (overhang, venetian blinds,lightshelf) by using dynamic simulation and dynamic daylight performance metrics.The results show that: the lightshelf is more advantageous to improve the quality ofoffice space daylight environment.In order to make a good use of lightshelf, the paper makes a further research onlightshelf based of office709, and analyses the impact of various factors of lightshelfon dynamic daylight performance metrics, such as: inner shelf size, inner and outershelf angle, height of the shelf, group number, etc. The research put forward someparameters of lightshelf which are suitable for this office space. This method can beapplied to other office spaces when lightshelf is chose to use.The innovation points of this paper include the followings:1. Dynamic daylight performance metrics are verified to be superior thantraditional static daylight performance metrics by the simulation of Radiance andDaysim.2. It is the first time for the use of dynamic daylight performance metrics inevaluating the office space daylighting situation. This evaluation can better reflect thereality of the daylighting effect and provide more reliable reference basis for thearchitect;3. This paper uses the method of dynamic simulation, makes daylightperformance metrics to be evaluation standards, and makes reasonable choice onauxiliary lighting system. Researching on the application of lightshelf is the first timein China. This simulation and evaluation method can be applied to other buildingtypes.