0 Preface
In recent years, the pressure caused by large energy consumption and environmental pollution has prompted people to focus on promoting energy conservation and emission reduction policies. In particular, the pressure of economic costs caused by the global economic crisis has forced all sectors to strive for energy conservation and consumption reduction. Building energy consumption, which accounts for 1/3 of total energy consumption, bears the brunt. How to reduce lighting energy consumption with the natural lighting characteristics of buildings has become an important task for architects. The main lighting method of the existing office buildings is side lighting, which is designed to meet the mainstream of the large depth and large open office space design. The lack of lighting in the indoor deep depth is an unavoidable problem. At present, artificial lighting has become the main means to make up for the lack of lighting in large-depth office buildings, and there are also design trends in the use of new materials such as optical fibers [1-2], but it is not conducive to popularization due to high cost; another traditional lighting method -- The top lighting has a good effect on alleviating the indoor large deep illumination attenuation problem and improving the uniformity of lighting [3]. However, due to the large restrictions on the building structure, the application effect in high-rise office buildings is not obvious, but in the small and medium-sized low-rise office buildings, there is sufficient installation and use space. Architects are constantly exploring the side lighting and the top lighting. Combination method.
Through the combination of various lighting methods in a village and town ecological office building, through the simulation calculation and actual operation effect analysis, it is hoped that some natural lighting forms that are generally applicable to similar buildings can be used by architects.
1 lighting port
The office building is located in the southern part of the city, and belongs to the hot summer and cold winter zone. In the design and planning, a number of land-saving and water-saving technologies such as earth-filling and backfilling were used. The total area is about 656 m2. The south side of the building adopts a sloping roof structure and is divided into upper and lower floors on the north side. The south direction of the building is divided into three office areas by a low partition, but the upper space is kept connected, and the north direction is mainly an auxiliary area such as a warehouse. The structural model is shown in Figure 1.
Side lighting is the simplest and most commonly used natural lighting method. It also has the functions of ventilation and viewing. It is widely used in office buildings. The appropriate window and wall spacing creates a layered façade. The side windows that can be opened can also be used. As a fire emergency escape. According to the research results of Sui Jianguo, the size of the side windows, the installation height and other factors are closely related to the comfort of indoor light and thermal environment and the energy consumption of the building. Therefore, the side window of this building design has received special attention. However, the simple side has a large limitation on the depth of the light incident chamber. According to experience, it is about 1.5 times the height of the window top [2]. It is obvious that the office with a depth of about 8 m in the building cannot meet the lighting requirements.
In order to enhance the effect of side lighting, while making full use of the conditions of the top of the slope, a high-side lighting window is opened in the middle of the office, which can guide more natural light into the room. The high-side lighting window has nothing to do with the viewing. It is only used for lighting. Its effect on the indoor light environment is to reduce the illumination at the near window, and at the same time, the illumination decreases with the depth attenuation rate, which helps to improve the indoor lighting. Lighting uniformity.
The light-environment analysis software ECOTECT V5.5 was used to analyze the lighting effect of the design model. The numerical results are shown in Figure 2, which shows that the lighting parameters of the working surface in the office area 1 and the office area 3 have reached 2% of the lighting design standard [6]. The office area 2 sandwiched between the two does not reach the design threshold after 3 m from the window. The main part is because the middle part of the office area 1 has some light of the west side window; the office area 3 is adjacent to the entrance hall, and the area of ​​the lighting port is large, and the light shielding is relatively small; and the office area 2 is long and narrow, and the adjacent areas are indirect lighting. District, the lack of exposure to the lack of side lighting is undoubted. In this state, the entire office space presents the east-west “light-dark-light†and the north-south “light-dark†uneven illuminance distribution, which seriously affects the visual comfort of the room staff.
In response to this problem, it is improved by combining the top lighting, so that four top skylights are linearly arranged on the top of the upper part of the office area to enhance the lighting effect. Skylights increase the permeability of the building and its connection to the natural environment, helping office workers to ease work fatigue. According to the brightness distribution model of the ceiling, the brightness of the ceiling is more than three times that of the horizontal plane. Therefore, the effect of using the flat skylight as a natural light source is more than three times that of the side window, while the flat skylight transmits light in a more uniform manner, and is not easy for the outside world. Occlusion provides sufficient light flux for offices with large depths. Combined with the characteristics of the top of the building, the top skylight has a daylighting effect with a flat skylight and a high side window. This also greatly alleviates the shortcomings of the flat skylight in summer which is much warmer than the winter. In addition, the skylight uses double-layer hollow Low-E glass, combined with the sunshade inside the ceiling curtain, which can achieve a good light-transmissive and impervious effect, ensuring the comfort of the indoor light and heat environment.
The simulation result curve in Figure 2 shows that the overall illumination level of each office area after the skylight is increased is significantly improved compared with the original, especially the luminous flux in the rear part of the office area is greatly supplemented, and the illumination of the three office areas is also improved. The level tends to be consistent, which improves the overall lighting uniformity of the building.
