Traditional LED street lamp design of the main design focus on the number of lumens in the LED, while the heat is less concerned about the heat. In fact, the number of lumens of LEDs is increasing rapidly. In 2009, the number of single-turn lumens of LED production has reached 100 lumens, and this value is growing rapidly. Corresponding to the corresponding theory of heat transfer theory has matured, we can use the heat transfer means are basically clear: conduction, convection, radiation and phase change heat transfer. Therefore, in the heat or heat problems, the measures can be taken is visible, limited.
LED street lamp cooling technology, the general use of the way for the thermal plate, is a 5mm thick copper, in fact, is the temperature plate, the heat are temperature off; also installed heat sink to heat, but the weight is too large. Weight in the street lamp system is very important, because the street is 9 meters high, if the risk is too heavy, especially in the typhoon, the earthquake may be an accident. Domestic manufacturers use the world's first needle-like heat dissipation technology, needle-like radiator Of the thermal efficiency than the traditional sheet radiator has greatly improved, can make LED junction temperature than ordinary radiator 15 ℃ above, and waterproof performance is better than ordinary aluminum radiator, while the weight and volume also improved The In addition, for high-power LED lamps developed graphite heat sink also has good thermal conductivity and thermal performance.
Cooling methods are: natural convection heat, the installation of forced cooling fan, heat pipe and heat pipe heat and so on. Install the fan forced cooling system complex, low reliability, heat pipe and loop heat pipe cooling method cost is high. The street lights with outdoor use at night, the cooling surface is located on the side and the size of the smaller restrictions are conducive to the natural convection heat the advantages of air, so LED lights recommended as far as possible to choose the natural convection cooling method.
LED street lamp cooling design problems are: cooling fins area arbitrarily set, cooling fin arrangement is unreasonable, the arrangement of the cooling fins do not take into account the use of lamps, affecting the effect of fins play, emphasizing the heat conduction However, many manufacturers consider a variety of measures: heat pipe, heat pipe, plus thermal grease, etc., but did not realize that the heat eventually to rely on the appearance of the luminous area of the light away. Heat balance, if the fins of the temperature distribution is not uniform, will lead to a part of the fins did not play a role or the role is very limited.
Heat dissipation high power LED street lamps. The purpose is to solve the problem of high-power LED lighting, put forward a kind of air convection heat dissipation high power LED street lamp fixture, which includes a lamp cap assembly, lamp radiator body and lamp tail assembly, lamp radiator components for the arc cylindrical shell , Both ends of the opening, the arc cylinder on both sides of the facade, the facade also has an array of through-holes in the arc cylindrical shell cavity with 4 to 10 axial arrangement and arc cylindrical chord The two facades on both sides of the fixed-tandem thermal conduction plate, the vertical reinforcement plate and the arc-shaped cylindrical shell are also open with array through holes, Surface in the lamp body components within the formation of 5 to 11 hot air flow of the cooling channel. The utility model has the advantages that the heat dissipation surface of the heat radiating body cavity has a plurality of hot air flow, and the heat conduction surface is also used as the heat dissipation surface, the heat exchange surface is increased and the heat discharging efficiency is high.
LED street lamp cooling is one of the key issues to be solved, not only directly related to the actual operation of the LED luminous efficiency, and because LED lights brightness requirements, heat, and outdoor use of this environment is more harsh, if the heat is not good Will lead directly to LED rapid aging, stability is reduced. Because the outdoor use of road lighting, should have a certain level of dust and water features (IP), good IP protection will often hinder the LED heat. To solve this contradictory but have to solve the two issues is the design of road lighting should pay attention to an important aspect. In this regard is also the domestic application of LED lights in the road when the failure and unreasonable situation of the most. The use of domestic substandard and unreasonable situation basically have:
(1) the use of a radiator on the LED, but the LED connection terminals and radiator design can not reach IP45 and above levels, can not meet the GB7000.5 / IEC6598-2-3 standard requirements.
(2) the use of ordinary road lighting shell, in the light out of the light with a matrix LED, this design can meet the IP test, but because the lamp does not cause ventilation at work, the lamp cavity temperature will rise To 50 ℃ ~ 80 ℃, in such a high operating conditions, LED luminous efficiency is not high, while the LED life will be greatly discounted, in fact, there is a clear unreasonable situation.
(3) in the lamp with the instrument fan on the LED and the radiator for heat, the air inlet design below the lamp to avoid the rain into the outlet design of the LED light source in the back around. This can also effectively prevent the rain into the other radiator and LED (light source cavity) is not in the same cavity, this design is done as well, according to the requirements of the lamp IP test, can pass. This program, not only to solve the problem of LED cooling, but also to meet the requirements of the IP level. But this seemingly good design, in fact there are obvious unreasonable situation. Because in most of the use of road lighting in China, the amount of dust in the air is large, and sometimes will reach a large (such as dust storms), such lamps under normal conditions for some time (about three months to Six months), the internal radiator will be filled with dust within the gap, so that the radiator effect greatly reduced, and finally make the LED due to high temperature and service life is significantly shorter. The lack of this program is that it can not be used consistently.
To take into account the road lamps in the LED heat and IP protection, a more reasonable design guiding ideology is:
A, in the key heat location, the use of thermal panels. The heat transfer plate is inside the metal plate, are equipped with a refrigerant flow of fine ducts, and in the fine duct filled with refrigerant, when a part of the heat conduction plate heat, the fine tube of the refrigerant will flow quickly and heat Ground conduction. Good thermal conductivity of the thermal conductivity of the plate can be achieved with the thickness of copper plate 8 to 12 times, although the price is higher, but if used in key parts of the LED heat will play a multiplier effect.
B, the design of the lamp shell into a radiator-like. Most of the road lighting shell is aluminum, thedirect use of the lamp outside the shell as a radiator can guarantee the requirements of IP protection level, you can get a lot of cooling area, in addition, the lamp shell composed of radiators in the dust, Can be washed by natural wind and rain, which can guarantee the continued effectiveness of the radiator work.