Introduction to LED Street Light Experiments in Chengdu in 2008

According to editors of Zhongzhao.com: It is true that LED street lamps are developing at a very fast speed and have great development potential. It is very likely to become a new product to replace traditional light sources in the future. In the context of the country's vigorous promotion of energy conservation and emission reduction, Nanjing, Suzhou, Chengdu and other major street lamps nationwide began to conduct test experiments specifically for LED street lamps a few years ago, making themselves a faster and healthier development of this product. Supporting power: Pay close attention to and keep abreast of the technological development level and market application of this industry, so that it can be promoted and applied when the technical performance, service life, maintenance cost, and cost performance are mature.

In recent years, the development of various new types of light sources has advanced by leaps and bounds, especially with the advancement of semiconductor production technology, high-power LED chips have gradually entered the field of lighting. Since 2006, we have been paying attention to the technical development of LED street lamps. Since then, we have been closely monitoring the development of this industry through various LED streetlight test experiments every year. Last year, we conducted another large-scale LED streetlight special experiment. The basic situation of the experiment is as follows (in view of the fact that the current development of this industry is very fast, this presentation only represents the end of the test product at the end of 2008). Technical level):

First, the experimental object

Before the experiment was officially launched, a large amount of product information was collected through various channels. Some of the information was also learned from some of the brothers who used LED street lamps, and finally 8 LED street lamp manufacturers were selected. Although it is not possible or impossible to cover all LED street lamp brands, the selected 8 should represent the advanced level of the current LED street lamp R&D and manufacturing industry. On average, each family purchased about 6 baht and a total of 52 street lamps.

The current LED street lights have many specifications, and do not form 400W, 250W, 150W and other power series like high pressure sodium lamps. According to the actual test, the power of various models of LED street lamp system in this experiment is between 106W and 188W, and the power of the light source is 71W to 170W.

Second, the purpose of the experiment

1. Verify the energy-saving effect: According to the measured efficiency of the LED street lamp, compare the efficiency of the high-pressure sodium lamp and verify its energy-saving effect. We believe that the fundamentals of energy conservation are to improve the efficiency of energy use. Therefore, the energy-saving effect of lighting products should be judged by the luminous efficiency.

2. Comparison with high-pressure sodium lamp: At present, the most used road lighting is high-pressure sodium lamp, which compares the light and electric parameter data of the tested LED street lamp with the high-pressure sodium lamp.

3. Analysis of economic benefits: As a user, an important purpose of energy conservation is to save money, but the transformation itself also requires a large amount of investment, the labor cost required for the transformation, the maintenance cost in the later period, and whether the investment can be recovered within the life cycle. The economic benefit analysis of this experiment is also one of the experimental purposes.

4. Feasibility conclusions for promotion and application: According to the above comparative analysis, the conclusions of the feasibility of the application of LED street lamps are obtained.

Third, the experimental content

This experiment is mainly for LED street lamps of 8 manufacturers and a set of high-pressure sodium lamp sets of international famous brands. From the actual use of many years, the price and technical level of the high-pressure sodium lamp lamps of this brand model are selected among the similar products. Upper level), the experimental content includes laboratory test, field test and other tests.

1. Laboratory test: Entrust professional institutions to test the light parameters such as voltage, current, active power, power factor, higher harmonics and other light parameters of the lamp and the light output of the lamp.

2. On-site test: The average illuminance and illuminance uniformity of the original high-pressure sodium lamp are measured in the experimental section; after the high-pressure sodium lamp is replaced by the LED street lamp, the average illuminance and illuminance uniformity of various brand lamps are measured.

3. Other tests: Every quarter, the organization staff will measure the spot illumination at the site, collect data, and summarize the law of LED road light decay. The maintenance personnel of the facility regularly inspect the experimental sections, find faults in the light source and electrical appliances, and count the failure rate of the LED streetlights.

As nighttime functional lighting, what we ultimately need to buy is actually light, not what kind of light source appliances. It’s like we go to the supermarket to buy water. I need water. As for the plastic bottle or the glass, it is not what I need, but it will affect the purchase price. So we can convert it to the same price of one liter, plastic bottle. How much water is, how much water is in the glass bottle, so as to make an economic comparison. Similarly, we calculated the cost of each luminous flux of each LED street lamp and high-pressure sodium lamp. The cost of sodium lamp is about 4 cents / lm, the cost of the most expensive LED street lamp is nearly 1 yuan / lm, the cheapest is also 4 Angle / lm or more. In contrast, the cost of purchasing 1 lm of light is the same as that of the sodium lamp, which is 23 times the average of the sodium lamp, with an average of 15 times and a minimum of 11 times. If you simply calculate the unit luminous flux purchase cost of the LED street light source, according to the 80-100lm/w chip commonly used on the market and the price of 40 yuan/w calculated by many manufacturers, the unit light flux purchase cost of the LED light source is 0.4-0.5. Yuan / lm. The price of a 250W high-pressure sodium lamp source is about 80 yuan, the light efficiency is generally above 120lm/w, and the unit light flux purchase cost of the sodium lamp source is 0.2 points/lm. Comparing, it can be seen that the unit light flux purchase cost of the LED light source is 200 to 250 times that of the sodium lamp.

The same purchase of 1 lumen flux, the average cost of using LED street lights is 15 times that of high pressure sodium lamps. Compared with high-pressure sodium lamps, LED street lamps currently do not have any advantages in terms of cost performance.

3. The actual service life of LED street lamps is yet to be tested. At present, the life of LED chips tested in the laboratory far exceeds that of high-pressure sodium lamps. This is uncontroversial. However, LED chip packaging and mass production are used as street lighting products, and then applied to harsh outdoor environments, it is necessary to face the heat, thunderstorms, dust, etc. Natural environment. Theoretically, the reliability coefficient of a system should be the product of the reliability coefficients of all components that make up the system. The number of components that make up LED street lamps is much higher than that of high-pressure sodium lamps. Therefore, the system reliability should be lower than the high voltage. Sodium lamp. The installation of the lamps in our experiment was carried out at the end of last year. Compared with the high-pressure sodium lamp source, whether the actual service life of the LED street lamp has an advantage remains to be tested.

4. The built-up road lighting system, the height of the pole, the elevation angle and the span are all designed according to the data of the sodium lamp. From the results of the overall illuminance of the test and the general change of the uniformity of illumination, due to the different types of lamps There is a big difference in the light distribution. In the case of keeping the existing pole height and layout mode unchanged, directly replacing the high-pressure sodium lamp with the LED street lamp may cause the lighting quality to decline.

Sixth, some reflections on the current development of LED street lights

1. Problems in the development stage

Since 2006, I have been paying attention to the development of LED street lamp technology. In recent years, I have been engaged in this aspect of testing. Looking at the current development speed of LED street lamp technology, it can be described as ever-changing and leaps and bounds. Regardless of chip efficacy, lamp efficiency, power supply performance, and light distribution curve, today's products are not the same as two years ago. We also believe that the future LED industry will move forward at a faster rate. It is precisely because of this, if the LED street lights are blindly promoted on a large scale, it is bound to have a new generation of LED street light products with higher luminous efficiency and more stable performance. At that time, in order to save energy, it is necessary to eliminate them. A generation of LED products, to replace it again? Users of any product want to use large-scale applications when the products are mature and the level of technological development is stable.

2, the color temperature of the light source

Most current LED street lights use high color temperature light sources because their light efficiency is higher than that of low color temperature LED light sources. However, there are two problems in the application of high color temperature light sources to the road lighting field. First, in foggy days, the light from the high color temperature LED street lights will be fully integrated into the background environment, although high pressure sodium lamps are not likely to provide a good lighting environment in dense fog conditions. However, in addition to meeting the lighting needs, road lighting also has a road-inducing function. In this respect, high-color temperature LED street lights are far less than high-pressure sodium lamps in foggy environments; second, foreign research results show that low color temperature environment gives people psychological The security is higher than the high color temperature environment, which is especially important in the densely populated residential area. Most of the current LED street lights use white light chips with high color temperature, which gives people a psychological affinity, intimacy, and a sense of security far less than high-pressure sodium lamps.

3, large-scale replacement problem

If the method of directly replacing the high-pressure sodium lamp with the LED street lamp is adopted, the residual value of the replaced high-pressure sodium lamp cannot be ignored except for the problem that the aforementioned lighting level is lowered. If it is replaced on a large scale, the high-pressure sodium lamps that are still in service and are in good service are replaced. Isn't it a waste of this part of the assets being abandoned without using them? Therefore, when we consider the large-scale replacement of high-pressure sodium lamps with LED street lamps, the residual value of the replaced high-pressure sodium lamps should be included in the retrofit cost, and the return on investment should be comprehensively calculated.

4. Over-promotion issues

The current LED industry is very hot. In the past two years, it has been overwhelming in the national road lighting industry, and the promotion effect has not been able to meet the expectations of many manufacturers. Here I would like to give an example of an LED lighting product: LED flashlight. If we go to the supermarket to buy a flashlight now, it must be all LED flashlights, it is difficult to find the most common incandescent small lamp bead flashlight. Why did the LED light source completely occupy the flashlight market in just one or two years? Because compared with the previous generation products, LED flashlight technology is more advanced and more advantageous: higher light efficiency, lower power, smaller size, better seismic performance, stronger light direction, and can be obvious as a user. It feels that LED flashlights are brighter, use less batteries, use longer, and are more convenient to carry. If you consider the energy saving and environmental protection, the number of used batteries reduced after using LED flashlights will be greatly promoted. the value of. However, during the entire replacement process, we did not see too much publicity for LED flashlights. Therefore, when the technical level of an industry develops to replace other industries, the market itself will automatically make the right choice. Conversely, I believe that forcing the promotion of an industry through vigorous publicity and other means is not conducive to its benign development at a time when the technology itself is still immature. In recent years, many urban road lighting management units have carried out some small-scale LED street light experiments. The actual result is that no matter the lighting level or the actual service life, the effect of the promotion is not achieved, so that the user’s heart is left very A good impression is also bad for the development of this industry.

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