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Which is better for high pressure sodium lamps and LED street lamps?

Oct. 18, 2019

Compared with traditional high-pressure sodium lamps, LED street light have the following advantages:

(1) As a semiconductor component, in theory, the effective life of an LED lamp can reach 50,000 hours, and the high pressure sodium lamp is much higher than 15,000 hours.

(2) Compared with high-pressure sodium lamps, the color rendering index of LED lamps can reach 80 or more, which is quite close to natural light. Under such illumination, the recognition function of the human eye can be effectively utilized to ensure road safety.

(3) When the street light is turned on, the high-pressure sodium lamp needs a preheating process, and the light needs a certain time from dark to bright, which not only causes waste of electric energy, but also affects the effective development of intelligent control. In contrast, LED lights can achieve optimal illumination at the moment of opening, and there is no so-called start-up time, so that good intelligent energy-saving control can be achieved.

(4) From the perspective of the illuminating mechanism, the high-pressure sodium lamp uses mercury vapor illuminating. If the light source is discarded, if it cannot be effectively treated, it will inevitably cause corresponding environmental pollution. LEDs and the like use solid-state lighting, there is no harmful substance to the human body, and it is a green light source.

(5) From the aspect of optical system analysis, the light source of high-pressure sodium lamp belongs to omnidirectional illumination, and more than 50% of the light needs to be reflected by the reflector to illuminate the ground. In the process of reflection, part of the light will be lost, affecting its utilization. . LED lights are one-way illumination, and the light can be directly directed to the illumination, so the utilization rate is relatively high.

(6) In the high-pressure sodium lamp, the light distribution curve needs to be determined by the reflector, so there are great limitations; in the LED lamp, the distributed light source is adopted, and the effective design of each electric light source can make the lamp The light source exhibits an ideal state, achieving reasonable adjustment of the light distribution curve, controlling the distribution of light, and the illumination is relatively uniform within the effective illumination range of the lamp.

(7) At the same time, economical LED road Light have a more complete automatic control system, which can adjust the brightness of the lamps according to different time periods and lighting conditions, which can achieve good energy saving effect.

Which is better for high pressure sodium lamps and LED street lamps?cid=314


Economical LED street light are used as street lamps to replace high-pressure sodium lamps. There are also some different opinions. For example, compared with high-pressure sodium lamps, LED lamps have lower luminous efficiency and poor illumination; LED lamps are too concentrated and the uniformity of illumination is relatively poor; The light attenuation rate of the lamp is large, and the service life is far from the theoretical life. In fact, these views can be explained by the following analysis.

The first is the so-called "luminous efficiency" problem. Under the current technical conditions, the luminous efficiency of LED lamps is indeed inferior to that of high-pressure sodium lamps. This is an indisputable fact, but the spectrum of high-pressure sodium lamps is concentrated in the yellow region, and its color temperature is low. Only 2000-2500K, and the color temperature of LED is relatively high, the neutral white temperature of LED street lamp reaches 4000-5000K, and the cool white temperature of LED reaches 5000-8000k. At the same time, compared with high-pressure sodium lamps, LED lamps have a higher color rendering index, which is close to natural light in actual lighting and can give people a comfortable feeling.

Secondly, the problem of "irradiation uniformity" is that although the illumination of the LED lamp is relatively concentrated, the secondary design of the optical path can make the light source of the lamp appear in an ideal state, realize reasonable adjustment of the light distribution curve, and control the light. Distribution to achieve uniformity of illumination.

Then there is the problem of“light decay”. In the actual application process, the service life of the LED lamp will be affected accordingly due to the long-term high temperature working environment. The life at different junction temperatures is shown in Figure 1. It can be seen that if the junction temperature is raised from 115 ° C to 135 ° C, the life of the LED lamp will be reduced from the theoretical 50,000 hours to 20,000 hours.

Under the current technical conditions, it is basically impossible to improve the luminous efficiency of the LED lamp in a short time, so the service life of the LED lamp can only be extended by strengthening the heat dissipation.

Compared with the use of high-pressure sodium for street lighting, LED street lights are more energy-efficient and environmentally friendly. Undoubtedly, with the advancement of science and technology, energy-saving and high-efficiency light sources will continue to emerge. As road lighting designers, they should continue to innovate and design, keep abreast of the use of new lighting technologies and new equipment, and always put energy conservation and environmental protection at the top of their work.


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