Industry news

2016August

A comprehensive analysis of the heat dissipation problem of LED street lamp

From: www.szbako.com Data:29/08/2016

Before

, many people put the main focus on the lumen of LED, and the LED lamp radiating less attention. In fact, the number of lumens of LED is rapidly increasing. The number of single watt lumens 2006 production of LED reached 50 lumens, and this number is still growing fast. With its corresponding theoretical system of heat transfer has been mature, we can use the means of heat transfer is also clear: conduction, convection, radiation and phase change heat transfer (such as heat pipe). Therefore, we can take measures to be visible and limited in heat transfer and heat dissipation.

according to the luminous flux (LM) and radiation flux (tile) the relationship between operation: where km = 683 LM /W, is the scale of luminous flux, radiant flux of the scale. It is said that 1W radiant flux under the most ideal conditions (blackbody radiation) may produce 683lm flux. So, even if the LED light efficiency reaches 200lm/w, it can not convert all the energy into light energy output, while the rest are converted into heat energy. In the long run LED lamp heat dissipation problem will be a long-term problem.

current LED street lamp heat dissipation methods are mainly: natural convection heat, the installation of fan forced cooling, heat pipe and loop heat pipe cooling, etc.. Forced cooling system with fan forced cooling system is complex, low reliability, high cost of heat pipe and loop heat pipe. The street lamp has the advantages of outdoor night use, the cooling surface is located on the side of the upper side and the smaller size and so on, which is conducive to the natural convection heat radiation, so the LED street lamp is recommended as far as possible to select the natural convection heat sink. There may be some problems in the design of

heat radiation:

1, the area of heat dissipation fins is set at will.

2, the cooling fin arrangement is not reasonable, the arrangement of the fin is not taking into account the use of the lamp, which affects the effect of the fin.

3, emphasizing heat conduction link, ignoring the convection heat transfer links, although many manufacturers to consider a variety of measures: heat pipe, a loop heat pipe, heat conducting silicone grease and so on, don't know to heat ultimately depends on the surface area of the lamps and lanterns scattered away.

4, ignoring the balance of heat transfer, if the temperature distribution of the fin is seriously uneven, it will lead to part of the fin (lower part of the temperature) did not play a role or role is very limited.

now LED street lamp cooling technology, the general use of the heat conduction plate is a piece of 5mm thick copper plate, actually is the uniform temperature board, turn off the heat source temperature, heat sink to install to heat, but too much weight. Weight on the street light system is very important, because the street lamp is 9 meters high, if too heavy to increase the risk, especially in the typhoon, earthquake may have an accident. Perhaps, in the future, LED is widely used in the field of street lamps, it is possible to form a modular heat dissipation will be a better solution to the LED street lamp heat radiation difficult situation.

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