Zhao Jianping Aladdin Lighting Network Blog
Zhao Jianping, deputy director of the Institute of Building Physics, China Academy of Building Research, professor-level senior engineer, chairman of the Outdoor Lighting Professional Committee of the China Lighting Society, and chairman of the China Lighting Engineering Standardization Association.
A few days ago, the media reported that the German town of Lem Ge used energy-saving measures along with the street lights, saving electricity costs of 40,000 pounds a year. If a resident comes out in the evening, they only need to dial a preset number, tell their own way to the phone and when the street light needs to be turned on. The computer at the other end of the phone will control the street light to light up at the right time. Automatically extinguished.
In order to let the street lights go with them, the German town of Lem Ge used a lot of technology, and some people may feel that the problem is big, but in the end they succeeded in saving a large amount of electricity, which proves that the hard work is worthwhile. In fact, the energy saving of road lighting does have great potential.
In recent years, China's urban road lighting has developed rapidly. In 1999, there were only nearly 3 million street lamps in the country. In 2007, it reached about 10.5 million baht, and the installed power reached 1.8 million kilowatts. The annual electricity consumption is about 5.9 billion kWh. This number is still quite large, and there are energy-saving articles to do.
Neglected design link
There are many kinds of energy-saving measures for road lighting, which can be classified into three categories: one is energy-saving measures in the design stage of road lighting, the other is energy-saving measures during operation, and the third is energy-saving measures in management.
Among these three types of measures, the current emphasis on the second and third categories in China is also quite good in the actual work. For example, in many places, in the operation of street lamps, the measures of turning off the lights and reducing the power in the middle of the night are taken. One of the two lamps in one street lamp is turned off, which reduces the illumination of the road as a whole and saves energy.
But to really do a good job of road lighting energy conservation, in fact, the first type of measures, lighting design, is the most important. It is the leader of energy conservation, energy-saving indicators are often completed by design, and other measures can only play a supporting role. The current problem in China is precisely the lack of attention to energy conservation in the design of road lighting. The relevant standards have already been available, but the implementation is not enough.
The newly revised "Urban Road Lighting Design Standards" stipulates the power density limit of motor vehicle traffic road lighting. It is required to ensure that the actual energy consumption is lower than the standard limit when designing. It is only taken further in the actual operation and management of street lamps. Measures to reduce energy consumption as much as possible.
Nowadays, the management of road lighting is generally the street lamp management office or the lighting management office. These institutions often fail to manage the design process and take over the operation and management of the street lights only after the road is completed. Road lighting is often designed to increase energy consumption for human reasons. Sometimes even the words of the leadership department can't be too dark, and the design illumination is greatly improved. There are also quite a few street lamp design departments or technicians who have no design qualifications, and can choose lamps, lamps and lamps at random, so that they are seriously exceeded or fail to meet the standards.
In the final analysis, the key to the problem lies in the lack of review and supervision of energy lighting in China's road lighting design. When the road lighting project is accepted, only safety, fire protection and other issues are emphasized, and the control of the contrast is not strict.
Street lights are not as bright as possible
The first thing to do in road lighting design work is to reasonably select the lighting standard value.
There are two issues that need to be addressed here. On the one hand, energy saving does not mean lowering the standard of lighting or not turning on the light. Last year, the commercial centers of several major cities in China had experienced the half-hour experience of landscape lighting, and the mood of tourists and customers was obviously affected. Reasonable urban lighting can play a positive role in the economy. The contradiction between economic development and energy conservation is not irreconcilable.
On the other hand, many people think that the brighter the road lighting, the better. In fact, road lighting does not need to be so bright. The main purpose of road lighting is to provide motor vehicles drivers with good visual conditions so that they can find obstacles in the range of 60 to 160 meters in front. Generally, the maximum illumination needs 30 lux (asphalt road). A large number of experimental studies have shown that the average illumination of the driver's evaluation for good road lighting is about 15 lux, not the brighter the better! Over-brightness is not only wasteful, but also causes light interference and light pollution.
The international lighting standards stipulate that the M1 road is 20 lux and the M5 road is 5 lux. The data shows that the illumination of the main road lighting in the United States is generally between 10 and 20 lux. The famous illumination of the Champs Elysées in Paris is only 17 lux, and the road illumination in Australia is between 10 and 20 lux.
The survey shows that some major cities in China, Beijing, Shanghai, Changzhou, Yangzhou, Wuhan, Changchun, Chengdu, Wuxi, Baoji, Hangzhou, Yinchuan, etc., have some road lighting with an average illumination of 45 lux or more, and even some roads on average. The illumination is 140 lux. The newly revised "Urban Road Lighting Design Standards" stipulates that the average illumination of the asphalt pavement is maintained between 20 and 30 lux. If you can lower these roads beyond the standard, you can save a lot of energy. Moreover, the energy waste brought by the design exceeds the standard, which is far from being compensated by the voltage regulation and voltage reduction in the later operation.
The correct approach is to communicate with the local municipal construction department and the traffic management department at the beginning of the road lighting design to determine which level of the designed road belongs to, and accordingly select the corresponding lighting standard value before starting the lighting. design.
New products and new technologies are in the midst of controversy
Lighting design work also includes the selection of suitable lighting fixtures to reduce energy consumption. This includes the selection of energy-efficient light sources, suitable lighting fixtures, energy-efficient rectifiers and control equipment, and even cable.
It is worth noting that many places ignore the functionality of road lighting and pay too much attention to decorative effects. In some places, a road type is required, and the artistic requirements of the street lamp are emphasized too much, and the functionality is neglected. Road lighting should be based on functionality, and the two should be considered together.
In terms of energy-saving light sources, high-pressure sodium lamps are currently used more. It is an energy-saving king in the world, and the technology is relatively mature and stable. But in recent years, there have been many new products. The current hot spot is how to use LEDs (light-emitting diodes) for road lighting. Experts and scholars at home and abroad are studying this issue. The future prospects of LED are still good. There are many demonstration projects in China, especially the landscape lighting effect is good, but it is used for road lighting, and the controversy is still very big. At present, the technical problems of heat dissipation and packaging of LED street lamps have not been completely solved. In theory, the LED has a long life span of 100,000 hours, but in fact it can only be 30,000 hours. Moreover, the problem of light distribution, that is, photoelectric distribution, has not been solved. The direct light of the LED is relatively strong, and the street light source needs to be diffused, as far as possible to become a bat-type light distribution, that is, not only to illuminate the light under the light, but also to illuminate the distance between the light and the light. If the two lights are very bright, the lights are very dark, whether it is suddenly from the dark to the bright, or vice versa, the human eye is difficult to adapt quickly, driving is prone to problems. China's urban road lighting design standards stipulate that the uniformity of illumination (the ratio of the minimum to the average) should not be less than 0.4.
In addition, in recent years, China has also done a lot of solar street lamp demonstration projects. However, the battery technology of solar street lamps is still not mature, the lifespan is short, and the investment is high. It will not work after two or three years. Who is going to maintain who is going to change is a big problem. Most of the current demonstration projects are mainly based on low power, and the lighting effect is not very good; the size of the panels required for high power is also large, and the price also rises. Moreover, the environmental pollution caused by batteries also needs attention.
However, the author believes that these new products and new technologies will continue to improve in the dispute and continue to move forward.
The appropriate illumination is determined, and the appropriate lighting equipment is selected. The rest of the design work is to carry out detailed calculations and arrangements to ensure that the various evaluation indicators of road lighting are met.
In short, as long as we can pay attention to the design process, I believe that China's road lighting energy-saving work can go up a step.
Zhao Jianping: I don't agree that LED will replace traditional light source.
The problem
Throughput is an important indicator of Ethernet testing. Many engineers believe that the Ethernet switching throughput should be its line rate, that is, no packet loss can occur at 100% traffic, and that it is illegal for the Ethernet frame interval IFG to be less than 96 bits. However, in the Ethernet switching throughput and packet loss rate test, a small amount of packet loss occurs in the long-term error test under the line speed condition. The reason is the cross-clock domain architecture of the Ethernet.
With the rapid development and application of industrial Ethernet technology, a large number of network problems have appeared along with it. According to statistics provided by Siemens, the network communication failure rate accounts for more than 70%, and the network equipment failure rate is less than 30%. After a network failure causes the system to shut down, the time required for fault diagnosis and location accounts for more than 80% of the total system downtime, while maintenance measures take up less than 20%. Therefore, real-time monitoring and analysis of network traffic is a major problem in the development and application of industrial Ethernet. Real-time monitoring and analysis of industrial Ethernet network traffic and timely detection and location of network problems play a vital role in improving the stable operation of the entire system. .
100M Switch,Fast Ethernet Switch,Fe Port,100M Ethernet Switch
Shenzhen GL-COM Technology CO.,LTD. , https://www.szglcom.com