5 LED Heat Dissipation Technologies
Heat dissipation is a major factor affecting the illumination intensity of LED flood lights. The heat sink can solve the heat dissipation problem of low illumination LED lamps. A heat sink can’t solve the heat dissipation problem of 75W or 100W LED lamps.
In order to achieve the desired illumination intensity, active cooling technology must be used to address the heat released by the LED luminaire assembly. Some active cooling solutions such as fans have a high life without LED luminaires. In order to provide a practical active cooling solution for high-brightness LED luminaires, the cooling technology must be low-energy; and can be applied to small luminaires; its lifetime should be similar to or higher than the source.
Heat dissipation method
In general, the heat sink can be divided into active heat sink and passive heat sink according to the way heat is removed from the heat sink. The so-called passive heat dissipation means that the heat of the heat source LED light source is naturally radiated into the air through the heat sink, and the heat dissipation effect is proportional to the size of the heat sink, but because of the natural heat dissipation, the effect is of course greatly reduced, and is often used in those space spaces. In equipment that is not required, or used to dissipate heat for components that generate less heat.
For example, some popular motherboards also adopt passive heat dissipation on the North Bridge. Most of them adopt active heat dissipation. Active heat dissipation is forced by heat sinks such as fans. The heat emitted by the heat sink is taken away, which is characterized by high heat dissipation efficiency and small size of the device.
Active heat dissipation, subdivided from the heat dissipation method, can be divided into air cooling, liquid cooling, heat pipe cooling, semiconductor refrigeration, chemical refrigeration and so on.
Air-cooled air-cooled heat is the most common form of heat dissipation, and in comparison, it is also a cheaper way. Air cooling is essentially a fan that takes away the heat absorbed by the heat sink. It has the advantages of relatively low price and convenient installation. However, it is highly dependent on the environment, such as rising temperatures and overheating performance.
The liquid cooling heat is forced to circulate away the heat of the radiator by the pump under the driving of the pump. Compared with the air cooling, it has the advantages of quietness, stable temperature stability and low dependence on the environment. The price of liquid cooling is relatively high, and the installation is relatively cumbersome. At the same time, install it as much as possible according to the instructions in the instructions to get the best heat dissipation. For reasons of cost and ease of use, liquid cooling heat dissipation usually uses water as a heat transfer liquid, so liquid cooled heat sinks are often referred to as water cooled heat sinks.
The heat pipe belongs to a heat transfer element, which fully utilizes the principle of heat conduction and the rapid heat transfer property of the refrigerant medium, and transfers heat by evaporation and condensation of the liquid in the fully enclosed vacuum tube, and has extremely high thermal conductivity and good isothermal temperature. The heat transfer area on both sides of the hot and cold sides can be arbitrarily changed, the heat transfer can be long distance, the temperature can be controlled, and the like, and the heat exchanger composed of the heat pipe has high heat transfer efficiency, compact structure, small fluid resistance, etc. advantage. Its thermal conductivity has far exceeded the thermal conductivity of any known metal.
Semiconductor refrigeration uses a special semiconductor refrigeration chip to generate a temperature difference for cooling when energized. As long as the heat at the high temperature end can be effectively dissipated, the low temperature end is continuously cooled.
A temperature difference is generated on each of the semiconductor particles, and a cooling sheet is formed by connecting dozens of such particles in series to form a temperature difference on both surfaces of the refrigerant sheet. By using this temperature difference phenomenon, the air cooling/water cooling can be used to cool the high temperature end, and an excellent heat dissipation effect can be obtained. Semiconductor refrigeration has the advantages of low refrigeration temperature and high reliability. The cold surface temperature can reach below 10 °C, but the cost is too high, and it may cause short circuit due to low temperature. Now the process of semiconductor refrigeration film is not mature enough. practical.
The so-called chemical refrigeration is the use of some ultra-low temperature chemicals, which use them to absorb a large amount of heat during melting to lower the temperature. It is more common to use dry ice and liquid nitrogen in this regard.
For example, using dry ice can lower the temperature to below minus 20 ° C, and some more ‘metamorphic’ players use liquid nitrogen to lower the CPU temperature below minus 100 ° C (theoretically), of course due to the high price and short duration, this Methods are more common in the laboratory or extreme overclocking enthusiasts.