LED plant light cooling method

LEDs and all electronic components generally generate heat and temperature rise during use or operation. If the heat dissipation problem is neglected, it will result in early burning of the LED due to high temperature. The design of LED luminaires is more complicated than traditional luminaires, including optics, mechanism, electronics and heat dissipation. Among them, “heat dissipation” is especially important, because most high-power LED luminaires currently convert most of their performance into heat when they work, if they cannot be exported to the luminaire. It will not be able to achieve the 50,000-hour lifetime claimed by the LED light source, and the heat will affect the luminous efficiency of the LED, resulting in severe light decay and damage to the lamp.

The luminous efficiency and lifetime of LEDs are closely related to the operating temperature, showing an inverse relationship ( CREE has a certain authoritative report in this regard). Due to the development of high-power LED technology, LED lamps face the severe challenges of thermal management and heat dissipation design, because the temperature rise will not only cause the brightness to drop, but also accelerate the deterioration of the lamp body and packaging materials when the temperature exceeds 100 degrees Celsius. . Therefore, in addition to the heat dissipation technology of the LED package component itself, the heat dissipation and heat conduction design of the LED plant lamp is the biggest key to maintaining the life of the LED lamp.

In terms of luminaire design, the LED chip , LED chip substrate, chip package, circuit design, system circuit board, heat sink fins and lamp housings have all tested the R&D capabilities of the LED industry in the middle, middle and lower reaches. The heat dissipation system can be divided into active heat dissipation and passive heat dissipation. The active heat dissipation includes fan forced heat dissipation and magnetic jet heat dissipation. Passive heat dissipation includes natural convection heat dissipation and loop heat pipe heat dissipation, which will be briefly introduced below:

1. Fan forced cooling:
Fan forced cooling, as the name implies, is to generate air convection by the fan, and the hot air is led out to the outside of the lamp for heat dissipation. The forced cooling of the fan can effectively discharge the heat, and the fan is forced to dissipate heat in the computer, the air conditioner and the automobile. LED plant lights should be designed according to the actual situation to determine the number of fans, as long as there is good heat dissipation, the number of fans is naturally the less the better, because the increase in the number of fans, the cost of the entire lamp and power consumption increase.

2. Electromagnetic jet heat dissipation:
Electromagnetic jet heat dissipation does not use fan blades to generate airflow. The structure is a hollow body with a film that oscillates the film at a frequency of 100 to 200 times per second using an electromagnetic or piezoelectric actuator to cause the film to oscillate up and down. The upper and lower displacement of the film, the air will flow into the hollow cavity and then ejected. The airflow after the jet will drive the surrounding air to generate eddy current and enhance the air convection capability. It has been applied to the manufacture of LED bulbs .

3. Natural convection heat dissipation:
Natural convection heat is directly contacted by air through a heat sink (for example, heat sink fins, lamp housings, system boards, etc.). The air around the radiator becomes hot air by absorbing heat, and then the hot air rises and the cold air drops. Naturally, it will drive the air to produce convection and achieve the effect of heat dissipation. With the introduction of high-power luminaire products, the use of natural convection heat dissipation requires a large heat dissipation surface area, so the heat dissipation fins are born, most of which are installed on the back of the lamp to provide a larger heat dissipation area and enhance the effect of convection heat dissipation. It is the most widely used one in the LED plant lamp industry.

4. Loop heat pipe heat dissipation When heat is transferred from the evaporator to the working medium in the loop heat pipe, the working medium absorbs heat and evaporates to the condenser, releases heat and condenses, and then returns to evaporation by the capillary force of the porous material in the evaporator. Repeat the loop. The effect of circuit cooling is undoubtedly not adopted by the LED plant lamp industry due to excessive cost and volume limitations.

It can be seen from the above that the LED plant lamp solves the problem of heat dissipation by increasing the thickness of the heat sink carrier, increasing the heat dissipation area and increasing the number of heat dissipation fans. The thickness of the heat-dissipating carrier should also be determined according to the actual temperature of the lamp. Increasing the thickness of the carrier can store more heat, but it will affect the speed of heat dissipation. It will also have a slight impact on the shape and cost of the LED plant lamp. Natural convection requires a large heat dissipation area, so how to maximize the heat dissipation area of ​​the LED plant lamp. The traditional method is to increase the heat dissipation fins (commonly known as heat dissipation profiles). Although the use of heat dissipation fins increases the heat dissipation effect, it also increases the overall weight and cost of the LED plant growth lamps. In addition, LED lamps often face problems such as dust accumulation and accumulation. For prolonged use, excessive dirt and dust accumulation can block the heat dissipation system. If it is not cleaned in time, it will seriously affect the heat dissipation effect of the lamp.

Therefore, the best design is to integrally form the outer casing and the heat sink to maximize the heat dissipation area, and also to maximize the area where the heat sink is in direct contact with the air, and to accelerate the heat transfer speed. The Guoshang International YOUTHS series LED plant lights are used. This technology, in addition, YOYTHS series of LED plant lights use the original cold and hot air duct isolation system, following the natural law of air convection, making its heat dissipation performance even more powerful. Then configure the high-efficiency silent fan to force heat dissipation, so that the heat dissipation effect of the entire LED plant light can be further improved.