LED street light replaces the feasibility assessment and measurement results of traditional lighting

With the improvement of LED luminous efficiency and life, coupled with the advantages of energy saving, energy saving and environmental protection, the feasibility of replacing traditional lighting lighting in the application of street lamps has been greatly enhanced. With the rapid growth of LED technology and continuous improvement of product characteristics, the demonstration plan of LED street lamps is launched in various countries. Through the evaluation and analysis of LED street lamp demonstration plan, it provides a reference for the investment and application of governments and LED manufacturers in the future street lamp market. .

LED Street Light Demonstration Program - Oakland, California, USA

For example, the US Energy Agency's demonstration of LED streetlights in Oakland, California, takes a two-stage evaluation process. The first-stage research team selects the parking lot in Auckland City to make measurements before and after the installation. The purpose is to evaluate whether the LED lighting may have a negative impact on safety when it is actually deployed on a general street; after confirming that the device has no special negative impact on the local people, the second stage of the operation is to install and evaluate the actual road and pass the local Residents survey estimates of satisfaction, acceptance, and economic costs.

This plan is an evaluation of the lighting effect of LEDs in streetlight applications. It replaces the original high-pressure sodium lamps with LED lights to conduct research on the roads in Auckland. The assessment methodology was evaluated using four projects, including source output efficiency, energy and power usage, user satisfaction surveys, and economic cost estimates. This assessment project expects the California region to more quickly introduce emerging energy technologies and applications that have not yet been adopted, through energy savings, reduced demand, market potential, market entry barriers, increasing costs, and expected technology lifecycles.

The purpose of this evaluation program is to evaluate the power, light source efficiency, and economic performance of high pressure sodium lamps compared to LED lamps. Potential economic needs and energy savings are assessed using average wattage and estimated annual kilowatts; light source performance is considered in terms of illuminance, uniformity, correlated color temperature, and the satisfaction of the relevant group. Finally, economic performance is replaced by equipment or replacement. The payback period (simple-payback), lamp life, maintenance costs, and power costs are evaluated.

Compared with traditional lighting sources, LEDs provide better lighting capabilities in terms of light source dispersion and energy saving, and at the same time change the general industry's perception of the use of high-quality light sources, and also apply to streets and general roads. The current street uses high-pressure sodium lamps for lighting, while others use metal halides, low-pressure sodium lamps or other types for lighting. The use of high pressure sodium lamps is due to their long service life and higher efficiency compared to other conventional lamps, but less selectivity in color supply. LEDs have a longer service life than high pressure sodium lamps, lower maintenance Cost, multiple types of color supply, low energy consumption and cost savings. However, the initial cost of using LEDs is still higher than that of commonly used lighting sources.

According to the US Energy Administration's report, the current LED technology changes are quite fast. Overall, LED's annual luminous efficiency is about 35%, and the cost can be reduced by 20%.

Plan implementation location and assessment method

This LED streetlight demonstration program replaces the original 121-watt high-pressure sodium lamp (HPS) with 15 盏 78 watt LED lights on the two roads of Sextus and Tunis in Auckland. For comparison and comparison, the east side of Sextus Road is installed. The new high-pressure sodium lamp is equipped with LED street lights on the west side; all the LED street lights are installed on the Tunis road, and new high-pressure sodium lamps are installed on the adjacent Cairo road. All fixtures are mounted at 28.5 feet above the road and have a pole spacing of 110, 120 or 160 feet.

The study found that the average power used per LED street light is 77.7 watts, which saves about 35% of the electricity compared to the average power of HPS of HPS, which is estimated to be 4,100 hours a year. Under 178 kWh.

Before each stage of the LED evaluation test, there will be a pre-test operation, all tests are carried out after dusk, and the distance between the lighting fixture and its two lighting fixtures is 110 feet, and the second and third of them are The distance between the two is 165 feet, and the distance between the three lights and the four street lights is 120 feet. As far as is reasonable, the illumination uniformity of the luminaire should be the same, but when the actual setting and evaluation, the street lamp can not be set within a yard within the distance when setting at the intersection. The distance from north to south is 12 feet. The width is adjusted to 10 feet.

The measurement method of this evaluation project is slightly different from the way of the international road lighting specification (IESNA) street lamp setting measurement. The international road lighting specification recommends that the measurement position should be within the range of one square of each distance directly below the light source. The measurement range of this study is in the light source. The bottom is directly measured and the center point position between the two light sources is measured, the maximum and minimum values of the illuminance are predicted within the test range, and the degree of difference between the uniformity of the high pressure sodium lamp and the LED lamp is recorded. The sensor is recommended to be installed 6 feet from the ground. The research team considered past measurement experience and recommendations and set the measurement position at 18 feet, which is the lowest height when the tripod is combined with the sensor.

The measurement process also includes the measurement of the temperature, and the high-pressure sodium lamp and the LED lamp are respectively measured every 20 minutes by using an electronic thermometer; in addition, in the night of measuring the LED lamp, the relative humidity is obtained by using the HOBO instrument U12 data recorder every 30 seconds. Other temperature measurements. There are related measurement information about LED lights and high-pressure sodium lamps, including photo shooting at various angles, power, illumination, color temperature and ambient temperature.

For the measurement of power consumption, a single high-pressure sodium lamp and LED lamp are measured by the DENTELite data logger. Since the test project has been in a period of time, the measuring instrument must be placed at a height position that is difficult to be directly contacted by the ground, and the research project personnel rely on it. The Auckland Street Light Maintenance Team assisted in the installation and removal of measuring equipment, and there were no special differences in power consumption during the measurement period.

Measurement result analysis

1. Differences between power demand and energy consumption

If the high-pressure sodium lamp is used for 11.97 hours per day, the average power consumption is 121W. Under the condition of 4100 hours of annual use, the total annual electricity consumption is 496kWh; if the LED lamp is used for 12.75 hours per day, the average power consumption is It is 78W, and the annual consumption is 4100 hours. It is estimated that the annual electricity consumption is 319kWh. Comparing the two measurements, it can be known that the use of LED lights can save 43.3W of power consumption, and is expected to save 178kWh per year. The daily luminaire usage time is between sunrise and sunset. Because the test for LED lights during the measurement period is closer to winter, the average LED lamp usage time is higher than that of the sodium lamp.

2. Illumination measurement results

The illuminance is measured in a range of 395 feet by 36 feet. It consists of 4 different positions, each with a distance of 110, 120 and 165 feet. Due to the position of the street light, the illuminance measurement cannot be directly under the luminaire, but The error in the overall study is not too large. The average illumination value is measured by the ruler candle. The maximum illumination and minimum illumination of the lamp are measured, and the maximum/minimum uniformity is calculated according to the maximum and minimum illumination.

According to the measurement results, as a whole, the illumination of the LED lamp is higher than that of the high pressure sodium lamp or a higher pressure lamp. In addition, since the LED lamp directly measures the illuminance slightly below the fixing device and is slightly darker than the high-pressure sodium lamp, the uniformity of the LED lamp is relatively good. In the case of dim light, the illumination of the LED street light can be maintained at the same illumination level or increased compared to the high pressure sodium lamp.

3. LED life and light attenuation

The life of the high-pressure sodium lamp is about 30,000 hours, and when it is used for 30,000 hours, the high-pressure sodium lamp is expected to provide 75-85% of the original luminous flux; and the LED lamp is at the ambient temperature of 25 ° C or lower, in the third When used for 10,000 hours, it still provides 90% of the luminous flux. Since the surface of the bottom of the LED lamp is made of acrylic synthetic resin, the luminous flux will also be affected by the yellowing of the bottom. According to the local climatic conditions, after ten years of use, it may be 2% due to the discoloration of the bottom of the lamp. influence level.

LED streetlights have considerable potential for energy savings in lighting applications. As can be seen from the results of this demonstration program, the setting of LED street lights has a positive impact on local residents, both in terms of visibility and night safety. However, the initial cost of LEDs is high, and the economic benefits and recyclability cycle are still a major concern for relevant units and manufacturers. Even though the emerging technology of LED is gradually accepted by most manufacturers in the current trend of promoting environmental protection and energy conservation, In the future, government departments will need more financial attention, subsidize local demonstration plans and assessments, and reduce the initial investment cost of manufacturers, so that LEDs can have more prospects and growth space in the future streetlight market. Fortunately, the current LED street lights in China are being driven by government projects, such as the “Ten Cities and Ten Thousand Miles” plan, as well as the demonstrations of the Olympic/World Expo/University Games, which are opening up unprecedented business opportunities, but we also pay attention to this background. To the phenomenon that manufacturers have “snacked” into the market, the quality of products is uneven, ignoring technology research and development, and excessive advancing has caused frequent problems in practical applications, which has led to users’ doubts about LED light sources, such as the recent editing of Optoelectronics News Network. According to the news, Shenzhen recently evaluated the LED streetlights in a certain road in the Science and Technology Park. Because it is open-ended testing, any manufacturer can participate, but in just one month, there have been “dead lights” in LED street lights provided by enterprises. Partially affected the user's confidence in LED lamps. Therefore, strengthening technology research and development and reserves, improving product reliability and stability will be an important factor affecting the future popularity of LED street lights.

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