Six Tips for Urban Landscape Lighting
Where does urban lighting energy saving start? I think the importance of urban lighting functions should be correctly understood first. The quality of lighting that meets the visual function is an indispensable condition for ensuring traffic safety, social security, and people engaging in production and cultural and recreational activities. This is a scientific conclusion drawn by human beings through long-term practice. Taking road lighting as an example, my country'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, improving road utilization at night
Where does urban lighting energy saving start? I think the importance of urban lighting functions should be correctly understood first. The quality of lighting that meets the visual function is an indispensable condition for ensuring traffic safety, social security, and people engaging in production and cultural and recreational activities. This is a scientific conclusion drawn by human beings through long-term practice. Taking road lighting as an example, my country'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, and improve road utilization at night.
my country's current electricity is not rich, especially when energy is in short supply, lighting energy saving often focuses on reducing the power of bulbs, reducing the number of lighting or shortening the lighting time and so on. With the continuous progress of science and technology and the needs of urban development, the energy saving of road lighting has jumped to a new level.
So clearly aware of these so-called "energy-saving" measures, it can also be said that the understanding of the importance of urban lighting functions is insufficient. Using this method to save energy is negative, unfavorable, and a measure that does not pay off. Still taking street lighting as an example: in May 1974, the US government announced that road lighting should be reduced to the national minimum standard of 6.5 lux, and the factory began to use street lighting on a road called kilometers long in Florida, USA from November 1974. A trial was conducted to reduce the relationship between traffic accidents and the results showed that night traffic accidents increased by 40%, equivalent to economic losses of 27,000 US dollars, and energy savings of 0.93 million US dollars. Accordingly, in June 1977, the U.S. government rescinded the decision. Another example is the impact of the global energy crisis that broke out in the Middle East war in 1973. From 1973 to 1974, the British government reduced public lighting, including street lighting, by 50%. During this period, lighting accidents at night increased by 100%. The twelfth, equivalent to an increase of 6 million pounds in economic losses. In the meantime, the energy savings is worth £100,000. To this end, in 1975 the British government announced that, for safety reasons, the energy required for lighting should be ensured.
It is not difficult to see from the above examples that it is not advisable to adopt power saving measures that impair the visual function in terms of social and economic benefits. Therefore, we should have a full understanding of the importance of lighting design functions. Lighting power saving is a comprehensive work involving many aspects. Under the premise of maintaining the proper lighting level. It is completely feasible to achieve energy saving. According to the actual situation in my country at this stage, combined with my practical experience in work, I put forward the following suggestions on lighting energy saving:
1. Reasonable determination of lighting standards
Energy saving in urban lighting is by no means achieved by reducing lighting standards. Energy saving should be emphasized on the premise of ensuring that roads at all levels meet the corresponding lighting standards. Therefore, whenever a road lighting project is not considered for construction, we promise to use light energy to make the illuminated environment meet the lighting standard requirements. First of all, determine the road lighting level, and carry out reasonable design according to different lighting places such as main roads, secondary roads, and residential quarters, so as to maximize the use of light energy. Usually, several schemes are made for analysis and comparison, and the scheme that is both economical, reasonable and energy-saving is selected. In terms of road lighting, it is generally more economical, reasonable and energy-saving to use a light source with a higher installation height and spacing and a high-power light source than a light source with a smaller installation height and spacing and a low-power.
2. Select high-efficiency and energy-saving light sources
On the basis of due consideration of the color rendering of the light source, the use of high-efficiency light sources is an important part of lighting energy saving. Usually incandescent lamps are used as the first generation light source. Fluorescent lamps and high-pressure mercury lamps invented in the 1930s serve as second-generation light sources. In the mid-1960s, after the breakthrough of translucent alumina ceramics and its sealing process, high-pressure sodium lamps entered the lighting stage and were known as the third generation of light sources: high-pressure sodium lamps have the highest luminous efficiency among high-intensity gas discharge lamps. It can reach 120 lumens per watt, which is 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 luminous flux is the best. After 8,000 hours of ignition, the light run can still be 80%-90% of the initial value, and the life span is more than 10,000 hours. High-pressure sodium lamps have become a widely used and energy-saving light source, and have been valued by energy departments and lighting designers. Recently, high-pressure sodium lamps have been widely used in road lighting, station wharf, railway port and factory lighting. Significant energy saving effect.
3. Scientific control of switching time
Whether the opening and closing time of urban lighting is accurate is also a major aspect of street lighting energy saving. The installed lamp capacity in our city was 700 kilowatts at the end of 1997. If the opening and closing time is accurately controlled, it will be calculated by 5 minutes less every day, then the annual energy saving About 21280 kWh, therefore, there is a lot to do in the control of the opening and closing time of urban lighting.
At present, the control methods of public lighting time generally include: manual control, clock control, photoelectric control, microcomputer control, etc.
Manual control generally requires a special person to be on duty, and it is carried out according to the intuitive feeling of the eyes of the on-duty personnel, because it involves various factors such as the visual judgment ability of the on-duty personnel, and the sense of responsibility. So it's hard to be on time.
Photoelectric control is a relatively common one currently used. According to the pre-adjusted action illuminance value, the photoelectric head collects natural light, and when the illuminance value is consistent with the action illuminance value, the photoelectric controller acts and turns on the lighting power. A few days ago, the photoelectric controllers sold on the market could not be adjusted to the ideal opening and closing illuminance value. In addition, it only has one action illuminance value adjustment potentiometer, and it cannot be separately adjusted to two action illuminance values for turning on the lights at night and turning off the lights in the morning. Certain defects.
The commonly used clock control are YPK2 type clock and YD-166B type time control switch. Although the manual operation is reduced, the delivery time of the n outlets changes every day. Therefore, it is more troublesome to adjust the timetable for the opening and closing of the lighting after a period of time. If it is not adjusted frequently, it will cause the opening and closing of the lighting to be either early or late. Affecting the play of lighting effect, in addition, due to scale limitations, battery power supply and other factors, it is also easy to cause control deviation.
Microcomputer control is the control data made by the daily sunrise and sunset time of 365 days in the whole year and stored in the microcomputer, which can automatically control the opening and closing of each day. Although the control overcomes some of the shortcomings of the previous control force methods, it cannot be intelligent, and there is still a phenomenon of early and late in opening and closing the lighting with the weather changes.
In addition to the above lighting control methods, midnight lights can also be used. When the night is quiet and there are few vehicles and pedestrians on the road, some lights can be automatically turned off. If there are several rows of street lights, turn off several rows or turn off the lights every other, and reduce the lighting appropriately. This requires designers to take into account various factors such as the control of midnight lights and the laying of lines.
Fourth, choose high-quality electrical components
High-pressure mercury lamps, high-pressure sodium lamps and metal halide lamps are all gas discharge lamps. They are arc discharges when ignited, and the bulbs have negative volt-ampere characteristics, that is, when the current increases, the lamp voltage does not increase but decreases. Components with positive volt-ampere characteristics to balance this negative characteristic, components with this characteristic are called current limiters or ballasts. At present, smart street lamp power savers are commonly used.
High-quality inductive ballasts have the characteristics of impedance stability, good volt-ampere performance, high power factor, and low power loss. In this way, the working current of the bulb can be stabilized and the service life of the bulb can be prolonged.
Reducing the power loss of the ballast is also an aspect of energy-saving work that cannot be ignored. For example, a 250W sodium lamp ballast with good quality has only a power loss of 20-25 watts, while the power loss of a poor quality ballast can reach about 40 watts. If you can choose high-quality products when choosing matching ballasts, then the energy saving effect is still very significant. Taking street lamps as an example, the mercury lamps and sodium lamps installed in Taizhou City use high-quality products for all supporting ballasts. If the average power consumption is reduced by 3 watts per ballast, and the annual lighting time is 4,000 hours, the electricity can be saved by 60,000 yuan. kWh.
5. Reasonable selection of lamps and regular maintenance
The main function of the luminaire is to distribute the luminous flux of the light source to the required direction to improve the utilization of light and avoid glare. Generally, lamps with high efficiency are made of materials with high reflectivity and advanced technology, such as electro-polished high-purity aluminum plates; protective covers with good light transmission properties, such as light-transmitting glass or plexiglass; Waterproof and dustproof, reducing light loss as much as possible. The efficiency of a luminaire refers to its utilization of the luminous flux of the light source. The efficiency of lamps made of any material is always less than 1 when the luminous flux radiated by the light source is reflected and transmitted. Assuming that the light source of the same power, a lamp with a higher efficiency, its luminous flux is 70%-80%. It is used, and the other is equipped with lamps with lower efficiency, and only 40%-50% of the luminous flux is used. Comparing the two, the low-efficiency lamps and lanterns consume nearly 30% of the power consumed by their light sources and fail to play their role, which is often overlooked. Therefore, when choosing lamps, try to choose lamps with good light distribution curve and high efficiency.
In addition, the lamps are inevitably polluted during use, such as aluminum oxidation of the reflector, dust accumulation inside and outside the protective cover, etc., which will inevitably cause loss of light. If maintenance is irregular, it is the same as the above. Most of the power consumed is wasted. Therefore, when choosing lamps and lanterns, choose lamps with sealing performance above IP55 to reduce maintenance workload.
6. Reduce reactive power loss and reduce power supply radius
At present, the quality of power supply in Taizhou continues to improve, and the voltage of the power grid is becoming more stable and normal. When the power consumption is significantly reduced in the second half of the night, the power supply voltage increases, and the power consumption of lighting power consumption also increases. 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 powered by the grid, and the power saver does not work. When the voltage is higher than the set voltage, the power saver is automatically put into work, and the grid voltage is stepped down by the power saver to supply the load, so that the lighting equipment 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 equipment itself.
When choosing the cross-sectional area of the wire in the street light pipeline, the loss of the line length to the voltage should be considered, and a reasonable power supply point should be selected at the same time, and 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 saving is great, and it is an important task for each of our street light management units. Only through continuous exploration and practice, from a big perspective and a small start, can we find a way to truly achieve the effect of lighting energy saving. , so that the limited electric energy can play a greater benefit.