Six suggestions for urban landscape lighting
Where does the urban lighting power saving start? I think we should first understand the importance of urban lighting functions. The quality of lighting that meets the visual function is an indispensable condition for ensuring traffic safety, social security, people's production and cultural entertainment activities. This is the scientific conclusion drawn by human beings through long-term practice. Taking road lighting as an example, China's newly revised road lighting standards guide road lighting workers to make reasonable lighting designs to provide lighting conditions that meet the driver's visual requirements and ensure drivers. And pedestrian safety, improve night road utilization.
At present, China's electric energy is still not rich, especially when energy is scarce, energy saving is often focused on reducing the power of the lamp, reducing the number of lights or shortening the time of lighting. Road lighting and energy saving have leapt to a new level with the continuous advancement of technology and the needs of urban development.
Therefore, it is clear that these so-called "energy-saving" methods can also be said to be insufficiently aware of the importance of urban lighting functions. Energy saving is negative in this way, and it is unfavorable. Still taking street lighting as an example: In May 1974, the US government announced that road lighting should be reduced to a minimum of 6.5 lux for national lighting, and that in November 1974, street lighting was used on a kilometer-long road in Florida, USA. The relationship between the reduction of traffic accidents and the traffic accidents was tested. The results showed that traffic accidents in the night increased by 40%, equivalent to economic losses of 27,000 US dollars, and energy savings of 93,000 US dollars. Accordingly, in June 1977, the US government cancelled the decision. Another example is the impact of the worldwide energy crisis that broke out in the 1973 Middle East War. The British government cut public lighting, including street lighting, by 50% from 1973 to 1974, during which nighttime lighting accidents increased by a percentage. Twelve, the economic loss is increased by 6 million pounds. In the meantime, the energy saving value is 100,000 pounds. To this end, the British government announced in 1975 that for safety reasons, the energy required for lighting should be ensured.
It is not difficult to see from the above examples: It is not advisable to use the power-saving measures that impair the visual function in terms of social benefits or economic benefits. Therefore, we should have a full understanding of the importance of lighting design functions. Lighting power saving is a comprehensive work involving more faces. Under the premise of maintaining the required level of lighting. It is completely feasible to realize energy conservation. According to the actual situation in China at present, combined with the practical experience of my work, I put forward the following suggestions on lighting energy saving:
First, reasonable determination of lighting standards
Urban lighting power saving is by no means achieved by reducing lighting standards. Energy conservation should be mentioned on the premise that roads at all levels meet the corresponding lighting standards. Therefore, whenever a road lighting factory does not count construction, we should allow the use of light energy to meet the lighting standards. First, determine the road lighting level, and design according to different lighting places such as main roads, secondary roads, and residential areas to maximize the use of light energy. Usually, several schemes are made for analysis and comparison, and a scheme that is both economical and energy-saving is selected. In terms of road lighting, it is generally more economical and energy-efficient to use a light source with a higher installation height and spacing and a higher power than a light source with a small installation height and spacing and low power.
Second, choose efficient energy-saving light source
On the basis of proper consideration of the color rendering of the light source, the use of high-efficiency light source is an important part of lighting energy saving. Incandescent lamps are often used as the first generation of light sources. Fluorescent lamps and high-pressure mercury lamps invented in the 1930s as second-generation light sources. In the mid-1960s, after the breakthrough of translucent alumina ceramics and its sealing process, high-pressure sodium lamps made it on the lighting stage, which is known as the third-generation light source: high-pressure sodium lamps are the most efficient in high-intensity discharge lamps. One can reach 120 lumens per watt, 2.2 times that of high-pressure mercury lamps and 8-10 times that of incandescent lamps. Moreover, the characteristics of the high-pressure sodium lamp are stable, and the lumen maintenance is the best. After 8,000 hours of ignition, the aperture can still be 80%-90% of the initial value, and the service life is over 10,000 hours, and its corrosion resistance and light transmission performance. Strong and other advantages, high-pressure sodium lamps have become a widely used and energy-saving light source, and have received the attention of the energy sector and lighting designers. Recently, high-pressure sodium lamps have been widely used in road lighting, station terminals, railway ports and factory lighting, etc. Significant energy savings.
Third, scientific control switch time
Whether the city lighting opening and closing time is accurate or not is also a major aspect of street lighting energy saving. The city's installed lamp capacity is 700 kW at the end of 1997. If the opening and closing time is controlled accurately, it will be calculated by less than 5 minutes per day. About 21,280 kWh, therefore, there is much to do in the control of urban lighting opening and closing time.
At present, the control methods of public lighting time are roughly: manual control, clock control, photoelectric control, and microcomputer control.
Manual control generally requires a special person to be on duty, according to the visual sense of the on-duty personnel's eyes as a standard implementation, due to the visual judgment ability of the duty personnel, responsibility and other factors. It is difficult to be on time.
Photoelectric control is a relatively common one. It uses the pre-adjusted action illuminance value to collect natural light, illuminance value and action illuminance value from the photoelectric head. When the photoelectric controller is activated, the lighting power is turned on. Recently, the photoelectric controllers sold on the market can not be adjusted to the ideal opening and closing illuminance value. In addition, there is only one action illuminance value adjustment potentiometer. It is not possible to adjust the night light and the morning light to two motion illuminance values. Certain defects.
Clock control Currently used are YPK2 type clock and YD-166B type time switch. Although the manual operation is reduced, the n outlets are changing every day. Therefore, it is more troublesome to adjust the opening and closing timetable of the lighting lamp after a period of time. If it is not adjusted frequently, it will cause the lighting to be turned on and off not too early - that is, late. Affect the role of lighting, and due to the limitations of the scale, battery power and other factors, it is easy to cause control deviation.
The microcomputer control is to store the control data into the microcomputer at sunrise and sunset every day for 365 days of the year, automatically control the opening and closing of the day, and add the photoelectric head to correct it, that is, it can be turned on and off in advance on a rainy day. Although the control overcomes some shortcomings of the former control methods, it can not be intelligent, and there is a phenomenon of early and late illumination in the Achilles weather change.
In addition to the above-mentioned lighting control method, a midnight light can also be adopted. When the pedestrians are quiet at night, the pedestrians on the road are scarce, and some of the lights can be automatically extinguished. If there are several street lights, the rows are extinguished or the lights are turned off, and the lighting is appropriately lowered. Degree, reduce power consumption, which requires designers to consider the various factors such as the control of the midnight light and the laying of the line.
Fourth, the selection of high-quality electrical components
High-pressure mercury lamps, high-pressure sodium lamps and metal halide lamps are all gas discharge lamps. When the ignition point is arc discharge, the negative volt-ampere characteristics of the bulb, that is, the lamp voltage does not rise but decreases when the current increases, and must be connected in series. Positive volt-ampere characteristics of the components balance this negative characteristic, and components with this characteristic are called current limiters or ballasts. At present, smart street light savers are commonly used.
High-quality magnetic ballasts are characterized by good impedance stability and volt-ampere stability, high power factor and low power loss. This will stabilize the lamp operating current and extend the life of the lamp.
Reducing the power loss of the ballast is also an aspect of energy saving work that cannot be ignored. For example, the good power loss of a 250W sodium lamp ballast is only 20-25 watts, while the poor quality power loss can reach about 40 watts. If you choose the quality products when you choose the matching ballast, the energy saving effect is still very significant. Taking street lamps as an example, mercury lamps and sodium lamps installed in Taizhou City, such as all matching ballasts, use high-quality products to reduce the power loss by 3 watts per ballast. The annual lighting time is 4000 hours, which can save 60000. Kilowatt hours.
Fifth, reasonable selection of lamps, regular maintenance
The main function of the luminaire is to distribute the luminous flux of the source to the desired direction to improve light utilization and avoid glare. Generally, high-efficiency lamps are made of high-reflectivity materials and advanced processes, such as electro-polished high-purity aluminum plates; light-transmissive protective covers such as light-transmissive glass or plexiglass; Waterproof and dustproof to minimize the loss of light. The efficiency of a luminaire refers to its utilization of the luminous flux of the source. The luminous flux of a luminaire made of any material is always less than 1 when the luminous flux of the source is reflected and transmitted. Assuming a light source of the same power, a luminaire with a higher efficiency, 70%-80% of the luminous flux. It is used, and the other is equipped with a lower efficiency lamp, and the luminous flux is only 40%-50%. Comparing the two, the low-efficiency luminaire consumes nearly 30% of the power consumed by the light source, and fails to play its role. This point is often overlooked. Therefore, when choosing a luminaire, try to choose a luminaire with a good light distribution curve and high efficiency.
In addition, the luminaire is inevitably polluted during use, such as aluminum oxidation of the reflector, dust accumulation inside and outside the shield, etc., which will inevitably cause loss of light, such as irregular maintenance, the same as above, the light source Most of the power consumed is wasted. Therefore, when selecting a luminaire, it is necessary to select a luminaire with a sealing performance of IP55 or higher to reduce the maintenance workload.
Sixth, reduce reactive power loss, reduce the power supply radius
At present, the power quality of Taizhou City is constantly improving, and the grid voltage is becoming more stable and normal. When the power consumption is significantly reduced in the middle of the night, the power supply voltage is increased, and the power consumption of the lighting power consumption is also increased. This not only shortens the life of the bulb, but also increases unnecessary energy consumption. Now the relevant unit has developed a power saver, which is installed in the lighting circuit and can be automatically put into operation according to the voltage value set by the user. When the grid voltage is lower than the set voltage, the load voltage is directly supplied by the grid, and the power saver does not work. When the voltage is higher than the set voltage, the power saver automatically puts into operation, and the grid voltage is stepped down to the load through the power saver, so that the lighting device always runs at the rated voltage. Moreover, the power consumption of the power saver itself is extremely small, which also saves the power consumption of the lighting device itself.
When selecting the cross-sectional area of the conductor in the street light pipeline, the loss of the length of the line should be considered, and a reasonable power supply point should be selected. The power supply radius should not exceed 500-800 meters, which can reduce the power loss of the line.
In short, the potential of lighting energy conservation is very large, and it is an important task of each of our street lamp management units. Only after continuous exploration and practice, from the perspective of the big place and small, we can find a way to truly achieve the energy-saving effect of lighting. To make the limited power to play a greater benefit.