Principle of LED light:
A Light Emitting Diode, a solid-state semiconductor device, converts electricity into Light directly.
Principle of high pressure sodium lamp:
High pressure sodium lamp is used after electrification, the excess energy of electricity is released in the form of light radiation, which produces light.
High-power LED street lamp is a kind of new lighting method which can realize the lighting demand by dc low-voltage lighting LED group. It has the characteristics of high brightness and good color rendering. In addition, the input of LED street lamps is low-voltage dc, which can be combined with solar energy, making solar LED street lamps a possibility of future road lighting.
1. Energy efficiency analysis and comparison
(1) high-power (≥250W) street lamp: high-voltage sodium lamp has high light efficiency. For high-power street lamp, currently LED has lower energy efficiency than sodium lamp.
(2) low power (≤150W) street lamp: LED lamp can save 10%~20% energy, up to 30%, but the high power is still not as efficient as sodium lamp.
2. Analysis of light source's light color on road lighting effect
As a motor vehicle driving fast road, main road, yellow light sodium lamp, to see the front 90~160m or so distance from the road condition, the effect is slightly better than white light, especially for fog, dust air conditions, sodium lamp has an advantage. For pavements, commercial pedestrian streets, residential areas and other roads, LED color display is better than sodium lamp, distinguish people's situation more clearly, has advantages.
The LED spectrum is much more comprehensive than the sodium lamp. The peak of both is at 580nm. The blue part of the LED only accounts for about 6% of the total luminous flux. LED red light is more widely distributed than high - pressure sodium.
Performance comparison of high pressure sodium lamp and LED light source
(1) comparison of service life
LED lamp is a kind of semiconductor diode, the theoretical life of its light source is very long (the premise is to meet the specified temperature range, L70 light decay standard), but the overall life of a lamp is not simply the life of the light source, the lamp also includes the influence of the lens. Therefore, the life of the final lamp should be limited to the shortest life of all lamp parts. The lifetime of a metal halide lamp is 6,000-12,000 hours. The lifetime of a high pressure sodium lamp is 20,000 hours.
(2) light utilization rate and luminescence rate
LED light source has the smallest luminous flux loss. High pressure sodium lamp is the light source of full-space luminescence. It is inevitable to absorb the light and block the light source itself. And using LED lamp as the light source, there will be no such loss, and the utilization ratio of light is higher than that of high-voltage nano lamp.
(4) comparison of energy conservation and environmental protection
LED lights are energy efficient and ultra-low power consumption. White leds use only a tenth as much energy as incandescent bulbs and a quarter as little as CFLS. And the LED light source does not contain the harmful metal mercury. High pressure sodium lamp light source contains metal mercury, metal sodium, short life, subsequent waste disposal to environmental pollution. LED light has good shock resistance and convenient transportation. Solid state package, belonging to the type of cold light source. So it's easy to transport and install.
(5) comparison of structure and cost
LED lamps generally have a more obvious sense of granulation, and its luminous position is relatively concentrated. Therefore, LED needs to do a better design on the uniform light, expand the point light source into a surface light source as far as possible, and improve the comfort level of the eyes. Moreover, many products will do LED dimming design to save energy.