The heat dissipation of LED street lamps is one of the […]
The heat dissipation of LED street lamps is one of the key problems to be solved. It is not only directly related to the luminous efficiency of the LEDs, but also because the LED street lamps have high brightness requirements and large heat generation, and the outdoor environment is harsh, if the heat dissipation is not good. It will directly lead to rapid aging of LEDs and reduced stability. Because road lamps used outdoors should have a certain level of dustproof and waterproof function (IP), good IP protection will often hinder the heat dissipation of the LED.
Solving this contradictory problem that has to be solved is an important aspect that should be paid attention to when designing road lamps. In this respect, it is also the most unqualified and unreasonable situation in the domestic application of LEDs in road lamps. There are basically unqualified and unreasonable situations in domestic use:
(1) The radiator is used for the LED, but the design of the terminal and the heat sink of the LED connection cannot reach the IP45 and above, and cannot meet the requirements of the GB7000.5/IEC6598-2-3 standard.
(2) Using ordinary road lamp housings, matrix LEDs are used in the illuminating surface of the luminaire. Although this design can meet the IP test, the temperature inside the luminaire will rise due to the non-ventilation in the luminaire. To 50 ° C ~ 80 ° C, under such high conditions, the luminous efficiency of LED is impossible to high, and the service life of LED will also be greatly reduced, in fact there are obvious unreasonable circumstances.
(3) The instrument fan is used to dissipate the LED and the heat sink in the lamp. The air inlet is designed below the lamp to avoid the entry of rainwater. The air outlet is designed to be around the LED light source.
This can also effectively prevent the entry of rainwater. In addition, the heat sink and the LED (light source cavity) are not in the same cavity. This design is good, and it can pass smoothly according to the IP test requirements of the luminaire. This solution not only solves the heat dissipation problem of the LED, but also meets the requirements of the IP level. But this seemingly good design actually has obvious unreasonable circumstances. Because in the use of most road lamps in China, the amount of flying dust in the air is large, sometimes it will reach a large extent (such as sandstorms). After using this type of lamp for a period of time under normal conditions (about three months to In the half year), the gap inside the internal radiator will be filled with dust, which will greatly reduce the effect of the radiator. Finally, the LED will have a significantly shortened service life due to the high operating temperature. The shortcoming of this program is that it cannot be used well and well.