LED street lamp cooling technology , generally used for heat conduction plate mode, is a 5mm thick copper plate, in fact, it is a temperature equalizing plate, the heat source is evenly warmed off; there are also installed heat sink to dissipate heat, but the weight is too large. The weight is very important in the streetlight system, because the streetlight is 9 meters high, and if the danger is too heavy, it will increase, especially in the case of typhoons and earthquakes. Some domestic manufacturers adopt the world's first needle-shaped heat dissipation technology. The heat dissipation efficiency of the needle-shaped heat sink is much higher than that of the traditional chip heat sink, which can make the LED junction temperature lower than the ordinary heat sink by 15 Â° C or more, and the waterproof performance ratio Ordinary aluminum heat sinks are better, and they are also improved in weight and volume. In addition, the graphite heat sink developed for high-power LED lamps also has good thermal and thermal performance.
The main methods of heat dissipation include: natural convection heat dissipation, forced cooling of the installed fan, heat pipe and heat dissipation of the loop heat pipe. Adding a fan to force the heat dissipation system is complicated, the reliability is low, and the heat pipe and the loop heat pipe heat dissipation method are high in cost. The street lamp has the advantages of outdoor nighttime use, the heat dissipation surface is located on the side and the body shape is restricted, which is beneficial to the natural convection heat dissipation of the air. Therefore, the LED street lamp is recommended to select the natural convection heat dissipation method as much as possible.
The problems in the design of LED street lamp heat dissipation include: the heat dissipating fin area is arbitrarily set, and the heat dissipating fin arrangement is unreasonable. The arrangement of the heat dissipating fins of the lamp does not take into account the use of the lamp, affecting the effect of the fin and emphasizing heat conduction. Link, neglect convection cooling, although many manufacturers have considered various measures: heat pipe, loop heat pipe, thermal grease, etc., but did not realize that heat ultimately depends on the external surface area of â€‹â€‹the lamp to dissipate. The balance of heat transfer, if the temperature distribution of the fins is severely uneven, will cause some of the fins to have no effect or limited effect.
Heat-dissipating high-power LED street light fixtures. The purpose is to solve the heat dissipation problem of high-power LED lamps, and propose an air convection heat-dissipating high-power LED street lamp, which comprises a lamp head assembly, a lamp radiator assembly and a lamp tail assembly, and the lamp radiator assembly is an arc-string cylindrical housing. Open at both ends, the two sides of the arc cylinder are the elevation, and the faÃ§ade is also provided with array through holes. In the inner cavity of the arc-string cylindrical housing, there are 4 to 10 axially arranged and arc-column and chord surfaces. The fixed vertical rib heat conducting plate, the vertical rib heat conducting plate and the two faÃ§ades on both sides of the arc string cylindrical shell are also provided with array through holes, the vertical rib heat conducting plate and the two sides of the arc string cylindrical shell The surface forms 5 to 11 heat dissipation channels for the flow of hot air in the radiator assembly. The utility model has the advantages that the heat dissipation body has a plurality of heat dissipation channels through which the hot air flows, and the vertical rib heat conduction plate also serves as a heat dissipation surface, the heat exchange surface is increased, and the heat discharge efficiency is high.
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 Â° C ~ 80 Â° 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 conditions.
(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.
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