Actual case comparison analysis LED street light with high pressure sodium lamp

1, on the light effect of led and nano lamps

In 2007, the best light source of led light can only reach 80lm/w, and the domestic one is even worse. After the luminaire, the actual application of the light effect is even lower. At that stage, most of the led light sources were used as indicator lighting and landscape lighting, and were not promoted in applications such as street lighting. However, some unscrupulous manufacturers and a few departments have hardened their interests in order to cause actual application failure. Such manufacturers still exist today. But this does not mean that the application of led has been this standard. At that time, the computer was still 386. Now? See things can't stay in the previous stage. Look at the present and the future. Now the OSZ series of light sources that Osram normally ships is 112-130lm/w.

Take the LED street lamp with the light source power of 100w as an example: the initial luminous flux is 11,200lm. Because the LED is unidirectional, the efficiency of the luminaire is high, the lens loss is 10%, and the luminaire loses 10%. The luminous flux of the lamp is 9070lm, and the total power of the lamp is 110w. Therefore, the lighting effect of this LED lamp is 82.5lm/w, and the nano light effect is from 90-140lm/w. However, because it is 360-degree light, the light applied to the illumination direction is very small, only 30%. It is necessary to achieve higher utilization of light by reflecting light in a portion of the non-applied direction. Due to the design and cost of the luminaire, the sodium lamp luminaire is only 40-45% efficient.

Take the 250w sodium lamp as an example: the initial luminous flux is 30000lm, and the luminous flux of the lamp is 13,500lm. The actual power of the 250w sodium lamp is 300w (this will be explained later), so the light efficiency of the 250w sodium lamp is 45lm/w.

Another very big problem with sodium lamp luminaires is that the illumination of sodium lamps is very poor. When the sodium lamp is in working condition, the temperature inside the lamp cavity should exceed 150 degrees. In the non-working state, because of the negative pressure, a lot of dust and insects are sucked in, which greatly affects the light-emitting effect of the sodium lamp.

From the above results, the luminous efficacy of the LED lamps at this stage is better than that of the sodium lamps. With the development and maturity of the LED technology, the luminous efficacy of the lamps will be greatly improved.

2, the actual power of led and sodium lamps

The power composition of the led light source luminaire: light source power + power loss = whole lamp power, now the efficiency of led drive can already achieve 91% or better, and does not need to do reactive power compensation.

The power of the LED lamp of the previous 100w light source: 100+100*(1-0.91)=109w The whole lamp power composition of the sodium lamp is more complicated, because the efficiency of the sodium lamp is only 0.38-0.45, and there is reactive power equal to the swimming power. The apparent power of the 250w sodium lamp without the reactive power compensation is as high as 627va. In order to solve this problem, the reactive power compensation part must be added. Now, the single-lamp local reactive compensation is generally 85%. The sodium lamp inductive rectifier consumes 20%, the electronic rectifier is 10% but costly and has a short life.

The power of the previous 250w sodium lamp: 250+250*20%=300w, there is still no power loss, line loss, transformer loss, etc. on the whole lamp line, so it will not increase in this, only in theory lower Value comparison.

3, on the life of led and sodium lamps

First of all, we must clearly understand the concept of lamp life and average life, and we cannot confuse these two concepts.

Lamp life refers to the time from the beginning of use of this luminaire to the time of death;

The average life of a luminaire refers to the time when a batch of luminaires is used until half of them die;

For the life of led lamps, now all major manufacturers are raising the life of the light source is more than how many hours. This formulation is unscientific, the theoretical life of LED light source is very long (provided that it is within the specified temperature range, under the L70 light decay standard), but the overall life of a luminaire is not simply the life of the light source, the luminaire also includes the drive, lens Part of the impact. Therefore, the life of the final luminaire should be limited to the shortest life component of all luminaire components.

Nowadays, the good driving power supply made in China and the lens made of silicon material can reach 50,000 hours (provided that the heat dissipation of the lamps meets the requirements).

For the life of sodium lamps, all manufacturers are raising the average life. Some people even suggested the life of sodium lamps. "Sodium lamps are used for street lamps with an average life of 3 to 5 years, energy-saving magnetic ballasts will not be less than 20 years, and lamps are also the same." I doubt this.

The following are two actual data: "Exploration of Street Lamp Maintenance Lamp Costs" by Baotou Municipal Municipal Engineering Management Office

A.1) According to the actual situation of the city, the average life of the bulb is calculated according to the average 6000 hours. The lighting time is 3960 hours. The theoretical replacement bulb replacement period is T=6,000/3, 960=1.5 years, and the bulb replacement rate is 0.67.

According to the actual operation experience of street lamps for many years, the bulb replacement rate should be 0.95.

2) The theoretical life of the ballast is 16,000 hours, the replacement cycle is T=16,000/3, 960=4 years, and the substitution rate is 0.25. According to years of operation experience, the ballast replacement rate should be 0.23.

3) The service life of the trigger is also set to 1.5 years, and the replacement rate is about 0.95.

4) The electronic control equipment is counted in 3000 times, the replacement period is 4 years, and the replacement rate is about 0.23.

b. In 2008, the book “Street Lights” by the Electric Power Press, the use of sodium lamps was about 4.13 million baht in more than 600 cities across the country. By the end of 2007, the average life expectancy of sodium lamps was 4000 hours.

In the first point, the replacement rate of the sodium lamp bulb in actual application is 0.95. In the second point, the average life of sodium is only 4000h. From this, it can be seen that the life of the sodium lamp is far less than 3, 5 years, and it can be seen that the theoretical analysis results are too different from the actual ones.

As for the life of led street lamps in the end? In the current state of LED lighting quality is uneven, I think we should first find the actual application of products that meet the basic requirements of some LED lamps, instead of seeing some very bad companies Very bad products will negate the led.

4. About environmental protection

The sodium lamp light source contains metal mercury and sodium metal, and the service life is short (relative to the LED). Subsequent waste disposal has great environmental pollution.

The LED does not contain the above-mentioned hazardous substances prohibited by the EU ROHS environmental protection directive.

5, on the lighting effect

a. Glare, as long as it is a lighting design problem, whether it is a sodium lamp or a led lamp, it needs to be improved in the light distribution design of the lamp, and has little correlation with the light source itself.

b. Color rendering. The sodium lamp has poor color rendering, and the reduction of the color of the object is not good for judging the depth of the surrounding environment. The led light source has good color rendering and can restore the actual color of the object well, but the white light is cold.

c. Transmittance to light. In foggy days, the lights require that the fog lights be turned on and slow. The fog lights are not used for lighting purposes, but only as an indicator.

For road lighting, the use of a penetrating light source is only a yellow spot that looks up at the head and has no practical effect on the illumination in front of the road.

d. For illumination. Illuminance is one of the important criteria for judging lighting effects. Because of the light distribution problem of sodium lamps, the illumination uniformity is not high. For better illumination uniformity and effect, many units are often over-illuminated in practical applications.

As one of the following test results in Qingdao:

LED street light when the micro-light electronics 150W

The electrodeless lamp is the Dutch rainer 150W

Xenon lamp manufacturers unknown 150W

High pressure sodium lamp Philips 400W

Time: April 24, 2009

Location: Jinggangshan Road, Huangdao District, Qingdao, Shandong Province

Organization unit: Qingdao Street Light Management Office and District Street Light Management Office

Specific location: There are 19 cars in the unopened section of Jinggangshan Road, including high-pressure sodium lamp, electrodeless lamp, xenon lamp 5 poles and LED 4 poles.

The height of the pole is 12-13 meters, the height is different. The spacing is 30 meters, and the pole is about one pole.

Road conditions: two-way four-lane, sidewalk width of 3 meters, single-sided road width of 8 meters, middle greening bandwidth of 4 meters. Asphalt road.

Measurement: In order to avoid interference from other lamps, the illuminance test selects the working point in the middle of the two shots of each lamp.

Take a line directly below the light source as a vertical line, and two points on both sides of the intersection lane. From the two points of AB, each takes 15 meters and is two points for CD. ABCD is a rectangle 15 meters long and 8 meters wide. In the 3*6 grid, there are 18 working points. The illuminance of these 18 working points was measured and averaged. And the illuminance uniformity is calculated.

Result: High pressure sodium lamp 65.77Lux 0.38

LED21.55Lux 0.32

Xenon lamp 22.77Lux. 0.17

Promise fluorescent lamp 16.22Lux 0.24

From the results:

1. There is excessive illumination in the illuminance of sodium, etc., but the uniformity of illumination fails to reach the standard of 0.4 for road illumination, not to say that it is not bright enough but there is a light and dark area (relative)

2, led street light illumination meets the requirements, but the same illumination uniformity is not up to standard, this product has a problem with the light distribution. However, even if the light distribution requirements can not achieve the actual brightness of the 400w sodium lamp, because the sodium lamp is excessive lighting.

3, Xenon lamp, stepless fluorescent lamp without considering the future will definitely eliminate the road lighting with high illumination requirements, the courtyard community road is still possible.

4. For illuminance uniformity. Illumination uniformity is another very important criterion for road lighting. Now the national road lighting table is 0.3 in the secondary road, 0.35 in the secondary road and 0.4 in the main road.

After the light source is lighted, the light source is a rectangular spot, which is very suitable for road lighting applications. When the illumination requirement is met, the illumination uniformity can reach 0.8, which is much higher than the sodium lamp.

The light distribution of the sodium lamp is formed by reflection. On the one hand, most of the light is lost, and the other part is difficult to achieve very good uniformity, that is, it can meet the road lighting standard (the LED has not come out when the standard is established, and the determination of these data They are all based on the best data that can be achieved by lighting at the time)

5, on the heat

The heat dissipation of led determines the life and light decay of the lamp. Because the country strongly supports the LED lighting industry, this industry is full of development.

Now there are a lot of companies in the electronic cooling industry that have entered the LED lighting industry, such as: Foxconn, Opus (formerly Kyushu Fengshen team came out) avc, coolermaster and so on. Their rich experience in electronic heat dissipation has brought a new heat dissipation concept to the heat dissipation of led lamps, and basically has reached the requirements of LED on the temperature. Take the Opus product as an example: at 35 degrees ambient temperature, the node temperature can be controlled to below 65 degrees.

6, on the foreign application of led

It has been mentioned that led in foreign countries has been denied, and it is suggested that led will not be applied abroad. I feel that there is a problem with the understanding of this announcement. It should be said that from the 2006-2008 stage when the LED technology is still in its infancy, some application effects have not reached the theoretical calculation, and it does not mean that the LED will be launched after 2008. On the contrary, Japan will replace all domestic commercial lighting with LED lighting in the next three years. On October 8, 2009, Los Angeles announced that it plans to replace the city's 140,000 high-pressure sodium lamps with LED lights in the next five years.

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