The main design of the traditional
LED street lamp head design focuses on the lumen number of the LED, while the heat dissipation of the LED lamp is less concerned. In fact, the lumens of LEDs are rapidly increasing. The single-watt lumens of mass-produced LEDs in 2009 have reached 100 lumens, and this number is growing rapidly. The corresponding theoretical theory of heat transfer has matured, and the heat transfer methods we can use are also basically clear: conduction, convection, radiation and phase change heat transfer. Therefore, the measures we can take on heat transfer or heat dissipation are visible and limited.
The LED street lamp heat dissipation technology is generally used as a heat conduction plate. It is a 5mm thick copper plate. It is actually a temperature equalization plate, which heats the heat source. It also has a heat sink to dissipate heat, but the weight is too large. The weight is very important in the street lamp head system. Generally, the lamp head is six meters high. If it is too heavy, the risk will increase. Especially in the case of typhoons and earthquakes, accidents may occur. 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 ° C or more, and the waterproof performance ratio Ordinary aluminum heat sinks are better, and they are also improved in weight and volume.
The cooling methods of the LED street lamp head mainly include: natural convection heat dissipation, added fan forced heat dissipation, heat pipe and loop heat pipe heat dissipation. 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 head has the advantages of outdoor nighttime use, the heat dissipating 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 head is recommended to select the natural convection heat dissipation method as much as possible.
The problems in the design of the LED street lamp heat dissipation include: the heat dissipating fin area is set arbitrarily, 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 effect, emphasizing Heat conduction links, neglecting convection heat dissipation, although many manufacturers have considered various measures: heat pipes, loop heat pipes, thermal grease, etc., but did not realize that heat ultimately depends on the external surface area of the lamps to disperse. Neglecting the balance of heat transfer, if the temperature distribution of the fins is severely uneven, it will cause some of the fins to have no effect or limited effect.
