With the advent of summer, everyone is inevitable is hot, the same led display is also more likely to heat, high temperature will lead to the rapid increase in the probability of failure of electronic components, resulting in led display reliability decline. In order to control the LED display internal electronic components of the temperature, so that the LED display in the working environment where the conditions do not exceed the maximum allowable temperature, the need for led display cooling design. Led display cooling design, how to low-cost, high-quality, is the content of this article.
There are three basic ways of heat transfer: heat conduction, convection and radiation.
Thermal conductivity: gas thermal conductivity is the result of collision between gas molecules when they are irregularly moved. The thermal conduction in the metal conductor is mainly done by the movement of free electrons. The thermal conductivity in a nonconductive solid is achieved by the vibration of the lattice structure. The thermal mechanism in the liquid mainly depends on the action of the elastic wave.
Convection: refers to the fluid between the various parts of the relative displacement caused by the heat transfer process. Convection occurs only in the fluid, and must be accompanied by a thermal phenomenon. The heat exchange process that occurs when a fluid flows through the surface of an object is called convective heat transfer. Convection caused by the density of the hot and cold parts of the fluid is called natural convection. If the movement of the fluid caused by external forces (fans, etc.), is called forced convection.
Radiation: the process of transmitting objects in the form of electromagnetic waves is called heat radiation. Radiation can transfer energy in vacuum, and there are energy forms of conversion, that is, thermal energy conversion to radiation and radiation energy into heat.
Select the cooling method, you should consider the following factors: led display heat flux, volume power density, total power consumption, surface area, volume, working environment conditions (temperature, humidity, pressure, dust, etc.) and so on.
According to the heat transfer mechanism, there is a natural cooling, forced air cooling, direct liquid cooling; evaporative cooling; thermoelectric cooling; heat pipe heat transfer and other cooling methods.
LED screen cooling design method
Heat electronic components and cold air heat exchange area, heat electronic components and cold air temperature difference, a direct impact on the cooling effect. This involves entering the led display box air volume size design, duct design. Ventilation duct design, as far as possible the use of straight pipeline to transport the air, to avoid the use of sharp turning and bending of the pipeline. Ventilation ducts should be avoided from sudden expansion or sudden contraction. The extension of the angle of not more than 20 °, shrink the cone angle should not be greater than 60 °. Ventilation pipes should be sealed as far as possible, all lap should be along the flow direction.
Led display box design, there are several points to note:
The vent should be located near the upper side of the box. The air inlet should be provided on the underside of the box, but not too low to prevent dirt and water from entering the box mounted on the floor.
The natural convection should be designed to facilitate forced convection. The air should be circulated from above the box, and a special inlet or vent should be used. The cooling air should be allowed to flow from the hot electronic components, while the need to prevent air flow short circuit. Inlet, the outlet should be set to filter, to prevent debris into the box.
Make sure that the air intake and exhaust are away from the design. Avoid using the cooling air again.
To ensure that the direction of the radiator cog direction parallel to the wind, the radiator can not block the airway.
Fan installed in the system, due to structural constraints, air inlet and outlet are often subject to various obstacles, the performance curve will change. According to practical experience, the fan inlet and outlet are best with the barrier 40mm distance, if there is space constraints, it should be at least 20mm.