With the coming of summer, everyone is inevitably exposed to extreme heat, and LED display screens are also more prone to heat. High temperatures will rapidly increase the probability of failure of electronic components, thereby reducing the reliability of LED display screens. In order to control the temperature of electronic components inside the LED display screen so that it does not exceed the specified maximum allowable temperature under the working environment conditions of the LED display screen, it is necessary to carry out heat dissipation design of the LED display screen.
How to achieve low cost and high quality in the heat dissipation design of the LED display screen is the content discussed in this article.
Three basic ways of heat transfer: conduction, convection, and radiation：
Conduction: Gas heat conduction is the result of the collision of gas molecules during irregular motion. Heat conduction in metal conductors is mainly achieved by the movement of free electrons. Heat conduction in non-conductive solids is achieved through the vibration of the lattice structure. The heat conduction mechanism in liquids is mainly due to the action of elastic waves.
Convection: refers to the heat transfer process caused by relative displacement between the parts of the fluid. Convection only occurs in fluids and is inevitably accompanied by heat conduction. The heat exchange process that occurs when a fluid flows over the surface of an object is called convection heat transfer. Convection caused by the different densities of the hot and cold parts of the fluid is called natural convection. If the movement of the fluid is caused by external forces (fans, etc.), it is called forced convection.
Radiation: The process by which an object transfers energy in the form of electromagnetic waves is called thermal radiation. Radiation can transfer energy in a vacuum, and there is a conversion of energy forms, that is, heat energy is converted into radiation energy and radiation energy is converted into heat energy.
When choosing a heat dissipation method, the following factors should be considered: heat flux density, volume power density, total power consumption, surface area, volume, working environment conditions (temperature, humidity, air pressure, dust, etc.) of the LED display.
According to the heat transfer mechanism, there are natural cooling, forced air cooling, direct liquid cooling; evaporative cooling; thermoelectric cooling; heat pipe heat transfer and other heat dissipation methods.
Heat dissipation design method of LED screen
The heat exchange area between the heat-generating electronic components and the cold air, and the temperature difference between the heat-generating electronic components and the cold air directly affect the heat dissipation effect. This involves the design of the air volume entering the LED display cabinet and the design of the air duct. When designing the ventilation duct, try to use straight ducts to transport air, and avoid using sharp turns and curved ducts. The ventilation duct should avoid sudden expansion or contraction. The expansion angle should not exceed 20°, and the contraction cone angle should not be greater than 60°. The ventilation duct should be as sealed as possible, and all overlaps should be in the direction of flow.
When designing the LED display cabinet, there are several points to note:
The exhaust hole should be set close to the upper side of the cabinet. The air inlet should be set on the lower side of the box, but not too low to prevent dirt and water from entering the box installed on the ground.
The design should make natural convection help forced convection. Air should circulate from the bottom of the box to the top, and a dedicated air inlet or exhaust hole should be used. Cooling air should flow through the heat-generating electronic components, and short-circuiting of the air flow should be prevented. Filters should be set at the air inlet and outlet to prevent debris from entering the box.
When designing, ensure that the air inlet and exhaust are far away. Avoid reusing cooling air.
Ensure that the direction of the radiator tooth groove is parallel to the wind direction, and the radiator tooth groove cannot block the wind path.
When the fan is installed in the system, due to structural limitations, the air inlet and outlet are often blocked by various obstacles, and its performance curve will change. According to practical experience, the fan inlet and outlet are preferably 40mm away from the obstruction, and if there is space limitation, it should be at least 20mm.
