1. About energy efficiency analysis and comparison The […]
1. About energy efficiency analysis and comparison
The lighting installation power of the two should be compared on the premise of reaching the same illuminance (brightness) level and similar lighting quality standards. Due to the high luminous efficiency of high-power lamps (250~400W) of high-pressure sodium lamps, which can reach 130~1401m/W, while the luminous efficiency of low-power lamps (100~150W) is about 80~1001m/W, high-power LED street lamps are currently used. 1W LED tubes are often used, and their luminous efficiency is similar, so it is advisable to analyze high-power street lamps and low-power street lamps separately.
2. Analysis of the light color of the light source on the road lighting effect
The correlated color temperature (Tcp) of the high-pressure sodium lamp is about 2100K, which is a warm color temperature, and its color rendering index (Ra) is only 23~25, and the color rendering is low; while the color temperature used by LED street lights is more than 5300K, which is a cool color temperature, which is better The Ra can reach 70~80, and the color rendering is good. As a fast road and main road for motor vehicles, the sodium lamp with a yellowish light is slightly better than white light for seeing the road conditions about 90~160m ahead, especially for foggy and dusty air conditions. It has advantages. For sidewalks, commercial pedestrian streets, residential quarters and other roads, the color rendering of LED is better than that of sodium lamps, and the status of people can be distinguished more clearly, which has advantages.
3. Service life analysis
The comparison service life should be based on the whole lamp life. High-pressure sodium lamps include light sources, electrical accessories (mainly ballasts, triggers) and lamps. Sodium lamps are used for street lamps with an average life span of 3 to 5 years. Energy-saving inductive ballasts will not be less than 20 years, and the same is true for lamps. The service life of LED street lights has no experience for the time being. Existing companies claim 50,000 to 60,000 hours, and there is no reliable basis yet. The requirements set by the US Energy Star are divided into two levels of no less than 35000h and 25000h. The main reason is that the life of the LED chip is very long, but it has a great relationship with many factors such as temperature and heat dissipation after packaging. In addition, there are electronics for driving circuit devices. The life of components, such as capacitors, is often only 8000h to 10000h. So overall, the service life of LED street lights cannot be compared with sodium street lights.
4. Maintain performance comparison
Users represented by urban street light management departments are more concerned about the maintenance performance of street lights. According to the analysis, the maintenance performance of the sodium lamp is good. The lamp only needs to be scrubbed and does not need to be replaced. The ballast is rarely replaced. The light source is replaced once every 3 to 5 years, which is also very convenient. For LED street lights, LED tubes, modules (including lenses, etc.), power supply devices, etc., components and components are more likely to be damaged, and maintenance and replacement are also difficult. It is likely to be replaced as a whole. The cost is relatively high. solve.
5. Luminous efficiency
The luminous efficiency of LED light sources is currently about 75Lm/w in the United States and Japan abroad, and about 65Lm/w in domestic LEDs. The luminous efficiency of the high-pressure sodium lamp light source is about 100Lm/w, and the luminous flux emitted per w is 25-35Lm/w higher than that of the LED. The luminous efficiency of 400w high pressure sodium lamp is as high as 120Lm/w.
6. Fog permeability
In road lighting, there is a big misunderstanding about the penetration of LED street lamps for heavy fog. Most people have always believed that the penetrability of LED street lights is lower than that of traditional sodium lamps, which is a misconception. We all know that the range of visible light is between 380nm and 780nm, and light in this range can be accepted and recognized by the human eye. It can be seen from the spectrogram that the spectrum of the LED is much more comprehensive than that of the sodium lamp. The peaks of both are at 580nm. The blue part of the LED only accounts for about 6% of the total luminous flux, while the sodium lamp has almost none. The distribution of the red light zone of the LED is wider than that of the high-pressure sodium lamp.