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How to heat outdoor LED display effectively

Due to the dense pixels of LED display, it has great heat. If it is used outdoors for a long time, the internal temperature is bound to rise gradually. Especially, the heat dissipation of large area [outdoor LED display] has become a problem that must be paid attention to. The heat dissipation of LED display indirectly affects the service life of LED display, and even directly affects the normal use and safety of LED display. How to heat the display screen has become a problem that must be considered.

There are three basic ways of heat transfer: conduction, convection and radiation.

Heat conduction: gas heat conduction is the result of collision between gas molecules in irregular motion. The heat conduction in metal conductor is mainly accomplished by the motion of free electrons. The heat conduction in non-conductive solid is realized by the vibration of lattice structure. The mechanism of heat conduction in liquid mainly depends on the action of elastic wave.

Convection: refers to the heat transfer process caused by the relative displacement between the parts of the fluid. Convection only occurs in the fluid and is inevitably accompanied by heat conduction. The heat exchange process of fluid flowing through the surface of an object is called convective heat transfer. The convection caused by the different density of the hot and cold parts of the fluid is called natural convection. If the motion of fluid is caused by external force (fan, etc.), it is called forced convection.


Radiation: the process in which an object transfers its ability in the form of electromagnetic waves is called thermal radiation. Radiant energy transfers energy in vacuum, and there is energy form conversion, that is, heat energy is converted into radiant energy and radiant energy is converted into heat energy.

The following factors should be considered when choosing the heat dissipation mode: heat flux, volume power density, total power consumption, surface area, volume, working environment conditions (temperature, humidity, air pressure, dust, etc.).

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

The heat exchange area of heating electronic parts and cold air, and the temperature difference between heating electronic parts and cold air directly affect the heat dissipation effect. This involves the design of air volume and air duct into the LED display box. In the design of ventilation ducts, straight pipes should be used to convey air as far as possible, and sharp bends and bends should be avoided. Ventilation ducts should avoid sudden expansion or contraction. The expansion angle should not exceed 20O, and the contraction angle should not exceed 60o. The ventilation pipe should be sealed as far as possible, and all laps should be along the flow direction.


Box design considerations

The air inlet hole should be set at the lower side of the box, but not too low, so as to prevent dirt and water from entering the box installed on the ground.

The vent should be set on the upper side near the box.

The air should circulate from the bottom to the top of the box, and the special air inlet or exhaust hole should be used.

Cooling air should be allowed to flow through the heating electronic parts, and short circuit of air flow should be prevented at the same time.

The air inlet and outlet should be equipped with a filter screen to prevent impurities from entering the box.

The design should make natural convection contribute to forced convection

The design should ensure that the air inlet and exhaust port are far away from each other. Avoid reuse of cooling air.

To ensure that the direction of the radiator slot is parallel to the wind direction, the radiator slot cannot block the wind path.

When the fan is installed in the system, the air inlet and outlet are often blocked due to the structure limitation, and its performance curve will change. According to the practical experience, the air inlet and outlet of the fan should be 40mm away from the barrier. If there is space limitation, it should be at least 20mm.

Post time: Mar-31-2021