Analysis of sensitivity of road lighting design parameters
In the past, road lighting design was usually based on the experience of the designer, and it was difficult to be scientific, reasonable, and economical. Nowadays, there are a lot of lighting design software that can be easily calculated to evaluate the rationality of the design. DIALux4.1 is a relatively good lighting design software developed by DIAL, Germany.
Sensitivity analysis, or sensitivity analysis, is a branch of mathematics: a concept in numerical algebra that is widely used in disciplines such as control engineering and structural optimization. In fact, it is to determine what happens to the output if one or more of the input values ​​change. According to the traditional theory, the sensitivity analysis must first have a mathematical function expression about the relationship between output and input, and then through a series of calculus operations can draw conclusions. However, the mathematical model of some problems is difficult to express, which makes the solution difficult. Nowadays, electronic computers can completely digitize very complex problems, which can solve many problems.
2 Introduction to the DIALux program The DIALux software has been in existence for 14 years, and the version has evolved from the initial 1.0 to the current 4.1. The function is more complete.
In the past, many designers used "concept" and "experience" to make judgments on lighting design. However, in the professional appeal of the lighting industry, if you want to really plan lighting, you need the lighting manufacturers to provide all kinds of correct lighting data. After computer simulation, the data and effects of the designer can be generated more accurately; otherwise, it can only be a personal experience value.
Based on years of observations in lighting technology and market research, DIAL of Germany found that lighting calculation software in many countries in the world is limited to the operation of a single label, and most of the lighting design cases are mostly integrated applications of lighting fixtures from multiple manufacturers. Does not meet the actual operational needs. Therefore, we have invited world-renowned manufacturers such as Philips, BEGA, THORN, ERCO, OSRAM, BJB, Meyer, Louis Poulsen and other companies to jointly invest in the development of new lighting software with "comprehensive application", and successfully launched in 1992. The DIALux lighting software, which first appeared in the Hannover exhibition, was recognized by all walks of life and gradually became the top brand of European lighting software.
Because DIALux can integrate various lighting fixtures, do accurate lighting calculations, and also have virtual reality functions, so that the entire space design case, whether it is indoor, outdoor, architectural, exhibition "lighting design planning", can The 3D perspective is perfectly presented in the computer, and all the lighting data are clearly listed in a graphical way. The operation interface is quite simple and user-friendly, so it immediately became enthusiastic in European countries. The resounding also established a recognized "standard" basis for the industry.
In addition to the existing more than a dozen European languages, DIALux has launched the Chinese version at the end of 2003.
In addition, DIALux's biggest feature is its "shared software" concept, and there are about two upgrades every year, so anyone can download it from the "DIALux" website.
Users can use DIALux as a lighting design laboratory, and repeat the experiment of the lighting configuration diagram on the software to the most perfect level before construction. In this way, there will be no more problems when the construction is completed, or the lighting angle is not appropriate, and the temporary replacement of the lamps, the configuration and the like occur.
At present, the German DIALux lighting software with strong lighting technology team and research background has become the best auxiliary tool for designers in Europe and America to realize the ideal of "perfect lighting" and "precision design".
*The main functions and features of DIALux:
• User-friendly work interface.
• Rich library of materials and modeling components.
• User-defined luminaire and module library.
• Choice of tens of thousands of lighting products.
• Set up a wizard mode such as indoor, outdoor, street, and lamp arrangement to complete the design quickly.
• Handle the way the fixtures and aiming positions are drawn.
• Flexible, precise, and fast calculations.
• Compatible with other software.
• Ability to view your work at any angle from 3D or floor plan.
• According to CIE (International Lighting Institute) standards.
• Professional and detailed reports impress customers.
3 Basic parameters of road lighting design model This paper refers to the road lighting design standard recommended by CIE (International Commission on Illumination), see Table 1.
The imaginary basic calculation model has a road width of 8 meters, two-way two lanes, illumination level M2, maintenance factor of 0.75, asphalt pavement type R3, and brightness coefficient of 0.07, see Figure 1, Figure 2.
Figure 1 Basic calculation model plan
Figure 2 Sectional view of the basic calculation model Lamp: Philips 204 Family SGS204 TP PC 1xSON-PP150W
Luminous flux: 17000 lm
Maximum light intensity:
Angle 70°: 305 cd/klm
Angle 80°: 120 cd/klm
Angle 90°: 11 cd/klm
The illuminating device is correctly installed in all directions capable of forming a prescribed angle with the lower vertical line.
Arrange to match the light intensity level G2.
Arrange to meet the glare index level D.5.
Wattage: 168 W
Arrangement: One-sided arrangement Light pole distance: 24.0 m
Figure 3 Street light distribution curve
4 basic calculation model calculation results
The calculation results of the basic calculation model are shown in Fig. 4-6.
Figure 4 Pavement and other illuminance map
Figure 5 Curve of the road surface seen by the track 1 observer
5 sensitivity analysis results
The three design parameters, such as the distance between the pole, the installation height of the lamp and the angle of the boom, have a great influence on the final result, so we should focus on the impact of their changes on the results.
Through the program calculation, the results of line 1 (line1) and line 2 (line 2) are obtained, as shown in Fig. 7-15. (Because TI is between 5% and 9%, SR is between 0.4 and 0.5, the change is very small, so they are not mapped.)
Figure 7 Effect of the change of the distance of the pole on the average brightness
Figure 8 Effect of change in pole distance on overall uniformity
Figure 9 Effect of the change of the distance of the lamp post on the longitudinal uniformity
Figure 10 Effect of the change in the installation height of the luminaire on the average brightness
Figure 11 Effect of changes in the installation height of the luminaire on overall uniformity
Figure 12 Effect of the change in the installation height of the luminaire on the longitudinal uniformity
Figure 13 Effect of the change of the boom angle on the average brightness
Figure 14 Effect of change in boom angle on overall uniformity
Figure 15 Effect of the change of the angle of the boom on the longitudinal uniformity The various results can be judged. It is a reasonable design to choose the distance of the pole from 24m, the installation height of the lamp is 8m, and the angle of the boom is 6°. Further, the influence of factors such as the length of the cantilever on the design result can also be analyzed.
6 conclusion
The use of DIALux 4.1 software to assist in the design of road lighting helps to fully justify its rationality during the design phase.
DIALux is a powerful and complete lighting design calculation software. As users increase, it will play a more powerful role in practice. (small soup)
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