Assessment and analysis of the LED lamps to replace traditional lighting scheme

With the LED luminous efficiency and lifetime improvement, coupled with energy-saving, energy saving and environmental advantages, greatly enhance the feasibility of replacing traditional lighting LED street lamp applications. LED technology is the rapid growth of the continuous improvement of product characteristics, the LED street lamp demonstration project then in various countries, through assessment and analysis of the LED street lamp demonstration project to provide Governments with LED manufacturers put into application in the next street lamp market to make a reference .
    LED street lamp demonstration plan - Oakland, California, USA

      LED street lamp demonstration program to assess the United States Energy Board in Oakland, California, for example, the project adopted a two-stage assessment process The first stage of the research team first Auckland City parking lot to do the measuring device before and after the device, The aim may have a negative impact on the safety assessment of LED lighting in general on the streets when the actual deployment; no special negative impact on the local population to confirm the device, the second stage device and evaluation in the actual road, and through local resident survey of satisfaction, to accept the estimate of the extent and economic cost.
      The Scheme is an LED lighting effects assessment in the street light applications, LED lamps to replace existing high pressure sodium lamp in Auckland City car on the road. Assessment methods to evaluate four projects, including the light output efficiency, energy and electricity use, user satisfaction surveys and economic cost estimates. This assessment project through energy savings, reduced demand, market potential, market entry barriers, gradually increase the cost and the expected life cycle of information, expect California to faster import of emerging energy technologies and applications has not yet been adopted.
      The purpose of this evaluation plan is to assess the high-pressure sodium lamps compared to the power of the LED lights, the light efficiency and economic performance. The potential economic demand and energy savings to the average wattage and estimated use of kilowatts to do assessment; light performance illumination, uniformity, correlated color temperature and related organizations level of satisfaction to consider, finally, the economic performance for the installation of a new or replacement payback period (simple-payback), lamp life, maintenance costs and the cost of electricity to do the assessment.
      Compared to traditional lighting sources, LED light source dispersed to provide better lighting and energy saving, while changing the general industry awareness on the use of high-quality light source, also used in streets and roadways on the road. The street using high-pressure sodium lamp illumination to do to others is the use of metal halide, low pressure sodium lamp, or other types for lighting. The use of high pressure sodium lamp is due to its longer life, higher efficiency compared to other traditional lamps, but less selective in color to provide LED than high pressure sodium lamp a longer life, lower maintenance costs, a wide array of color, low energy consumption and saves costs. However, the initial cost of the use of LED is still higher than the commonly used light sources.
      According to the report of the United States Energy Board, the current LED technology changes very fast, overall, LED luminous efficiency of the annual progress of about 35%, the cost can be thus reduced by 20%.

    Plan the location and evaluation

      LED street lamp demonstration project in Oakland, Sextus and Tunis two on the road to 15 and 78 watts of LED lights to replace the original 121 watts high pressure sodium (HPS), for purposes of comparison with the control, installed in Sextus Road, east of new high pressure sodium lamp, the west side of the installation of LED street lights; Tunis on the road all the installation of LED street close to the Cairo road is fully equipped with new high pressure sodium. All lamps are installed at 28.5 feet higher than the road, away from the pole for the 110,120 or 160 feet.
      The results showed that each LED lights use the average power of 77.7 watts, 121 watts compared to the average power of the high pressure sodium lamp HPS save about 35% of the electricity, the operation time of 4100 hours a year, is expected a year can save 178 kilowatts hours.
      Before each stage of the LED assessment test, there will be a pre-test operations, all tests are carried out in the evening, one of light between the lighting and the second light lighting distance of 110 feet, the second light and its three between a distance of 165 feet, the distance between the last three with its four street lights at 120 feet. Reasonable case, the lamp lighting uniformity should be the same, but the actual setting and assessment, street lights at the intersection set can not be completely set up within one yards distance from north to south distance of 12 feet, by the way street adjust the width to 10 feet.
      Slight differences in the measurement of this assessment project with the international road lighting specification (IESNA) street lights to set the measurement, the international road lighting specification recommends that the measurement location should be in the bottom of the light source is the distance of half the grid range, the measuring range of this study in the light directly below the center position between the two light sources were measured to predict the maximum and minimum value of the illumination in the test range, and record high-pressure sodium lamp with LED light uniformity degree of difference. Sensor is recommended to install location should be six feet from the ground. Research team to consider the past measurement experience and recommendations, the measuring position is set at 18 feet, this tripod with sensors in combination with up to a minimum height.
      Contains both the measurement of the temperature measurement process, electronic thermometers every 20 minutes on high pressure sodium lamps and LED lamps were measured; In addition, measurement of the LED lamps at night, every 30 seconds using HOBO instruments U12 data loggers for relative humidity and other temperature measurement. And LED lamps and high pressure sodium measurement information, including photos of various angles of photography, power, illumination, color temperature and ambient temperature to a total of four measurements.
      Power consumption measurement, DENTElite data logger to measure a single high-pressure sodium lamp with LED lights, the test project lasted over a period of time, measuring instruments must be set at the height off the ground is difficult to be in direct contact, research projects rely on Auckland City street light maintenance team to assist the installation of removable measuring equipment, the measurement period there is no power consumption situation caused by the special difference exists.

    Analysis of measurement results

    Electricity demand and energy consumption differences

    High pressure sodium lamps, such as 11.97 hours per daily average electricity consumption is 121W, and in 4100 the number of hours per year of use under the conditions of total electricity consumption of 496kWh; LED lights such as the daily use of 12.75 hours total, average electricity consumption 78W, the same year, 4100 hours of calculation, the estimated annual electricity consumption of 319kWh. Compare the two measurements can be learned, the use of LED lights can save 43.3W electricity consumption is expected to annually save 178kWh. Daily lamp usage time between sunrise and sunset, because the study measured during the test for the LED light is closer to winter, so the number of average LED lights use high pressure sodium lamp longer.

    (2) illumination measurement results

      Illuminance measurement range of 395 feet by 36 feet the size of the region, contains four different locations, the distance of 110,120 and 165 feet away, the street lights set the location factors, not directly below the lamps for illumination measurement, but overall impact above error is not great, foot-candles of illumination of the average as the unit of measurement fixtures maximum illumination with minimum illumination and calculated based on the maximum and minimum illumination of maximum / minimum uniformity.
      The measurement results can be learned, the whole of the illumination of the LED lamps are high pressure sodium lamp of the same grade or high pressure sodium lamps come later. In addition, LED light fixtures below the direct measurement of the illumination somber high-pressure sodium lamp, so the uniformity of the LED lamps is relatively good. Under low light conditions, compared to high pressure sodium lamp, LED street lamp illumination can be maintained under the same illumination level or increased.

    3.LED life and degree of the light fades

      High pressure sodium lamp life of approximately 30,000 hours and 30,000 hours of use, high pressure sodium lamp is expected to provide 75-85% of the original luminous flux; LED lights at an ambient temperature of 25 ° C or lower, its three Million hours when used, can provide 90% of luminous flux. 2% due to the surface of the LED lamps at the bottom of the acrylic synthetic resin, the luminous flux will have an impact with the bottom of the turn yellow look to the local climatic conditions, after decades of use, may be because the lighting at the bottom of discoloration the degree of influence.
      Considerable energy-saving potential of LED street lighting applications and can be learned from this demonstration project, the assessment results, the set of LED lights for the local population, whether it is to have a positive impact on the degree of visibility and night security. However, the high initial cost of LED, economic and recyclable cycle is still a major problem very seriously by the relevant units and manufacturers, even if this emerging LED technology to promote environmental protection and energy saving in the current trend gradually accepted by the majority of manufacturers still need more funding attention of government departments, subsidies for local planning and evaluation of demonstration, and reduce the initial investment cost of more play side allow LED street lamp market in the future outlook and room to grow. The good news is driven by the current LED street lamps are government projects, such as "10 City, 10000" program, as well as the demonstration of the Olympic Games / World Expo / Universiade is burst out of the unprecedented development opportunities, but in the context of this hot also noted that the vendor "rush" to get into the phenomenon of the market, product quality is uneven, and neglect of technology research and development, over-aggressive lead to frequent problems in practical applications, but lead to the users questioned the LED light source, such as the recent photoelectric News network editor to get the message, the Shenzhen recent Science Park Road on the LED lights to assess any vendor can participate in the open test, but in just one month has LED lights provide a "dead lights" phenomenon, partly affected the confidence of the LED lamps. Therefore, to enhance technology development and reserves, and improve product reliability and stability will affect the future of LED street lamp can really popular.