6 tips for how to choose quality LED high bay lighting for the factory?
In the energy consumption of the factory, lighting energy consumption has a certain weight. For example, in a 40,000 square meter building, the lighting load is about 400 KW. Therefore, in the selection of factory lighting, how to achieve energy saving and environmental protection is an important issue for factory designers. In addition to energy saving and environmental protection, the lighting fixture based on the new LED light source has the advantages of long life, fast response time, and concentrated light and light. In recent years, it has been widely accepted by consumers.
1.0 Power selection
Traditional industrial and mining lamps are mostly 250W or 400W high pressure sodium lamps and metal halide lamps, and compared with the characteristics of new LED lamps.
There are more obvious differences:
Considering the high-pressure sodium lamp and the metal halide light in the actual use and the secondary light-emitting problem, the actual luminous efficiency is much lower than 80 lm/W, and often cannot reach the nominal 70%. According to this, the power of the LED high bay light that we developed for the first time is set to about 120W.
Once the lighting effect is as expected, it is more than 50% energy saving than traditional lamps.
2.0 Light source selection
At present, the well-known brands of high-power LED light sources on the market are: CREE, OSRAM, NICHIA, Lumileds (the earliest LED), Taiwanese manufacturers’ crystals, Addison and domestic packaging manufacturers Shenzhen Wanrun, Zhuhai Ruifeng, Jiangxi Lianchuang and so on are also the brands that have been applied in the past.
In order to ensure the stability of the product, we use the most famous CREE/Lumileds light source.
3.0 LED Driver selection
LED driver is simply a circuit that provides normal working conditions (including voltage, current, etc.) for LEDs. It is also an indispensable condition for LEDs to work. A good driver circuit can also protect LEDs at any time. After all, LEDs are The core of the entire product.
LED driver circuits are usually divided into three types:
(1) Resistive current-limiting drive: It is simple to connect the resistors in the loop of the LED. By adjusting the resistance of the resistor, the drive current of the LED can be changed.
(2) Constant current drive: keep the current of the LED constant, let the LED work under the condition of constant current. To improve the efficiency and stability of the LED, reduce the brightness of the LED, the constant current drive is The best choice, high-power LEDs are driven by constant current.
(3) Constant voltage drive: keep the voltage at both ends of the LED constant, because the voltage of each color LED is different, so the LED light is rarely driven by constant voltage.
We used below famous Brand Driver.
4.0 LED Heatsink Thermal design
In high-power LEDs, heat dissipation is a big problem. For example, if a 10 W white LED has a photoelectric conversion efficiency of 20%, 8W of electric energy is converted into thermal energy. If no heat dissipation measures are taken, the core temperature of the high-power LED will rise rapidly, when its junction temperature (TJ) When the temperature rises above the maximum allowable temperature (typically 150 ° C), high-power LEDs may be damaged by overheating. Therefore, the heat dissipation design is also our most important content. Below we combine the aluminum substrate and the heat sink to discuss the heat dissipation design.
LED substrate selection
In LED product applications, it is often necessary to assemble a plurality of LED light sources on a circuit substrate. In addition to playing the role of the LED module structure, on the other hand, as the LED output power is getting higher and higher, the substrate must also play the role of heat dissipation to transmit the heat generated by the LED crystal, so in the material selection. Must meet structural strength and heat dissipation requirements. For the substrate, we compared FR4, ceramic substrate and MCPCB.
FR4 thermal conductivity is about 0.36W / m · K, can not meet the high power LED lighting cooling requirements
Ceramic thermal conductivity is greater than 80W/m·K, expensive, poor processability, and cannot be used in large areas.
The thermal conductivity of MCPCB is greater than 2.0W/m·K, the price is moderate, the processability is strong, and the technology is mature and can be produced.
The function of the heat sink is to absorb the heat transferred from the substrate or the chip, and then radiate it to the external environment to ensure the temperature of the LED chip is normal. Most radiators are designed for natural convection and forced convection.
Active radiators and tilting radiators. Their respective performance characteristics are shown in the table below.
Considering cost and stability, we use passive cooling. Passive heat sinks, according to materials, are divided into aluminum extrusion type (Al Extrusion) radiators and aluminum die-casting (Al Die-Casting) radiators.
Regarding the Heat sink & Fin & Vapor-Champer on the Heat sink, after testing, the emitter temperature does not drop much, and then it is not considered according to the process requirements of the engineering lamp.
5.0 LED Institutional design
The design of the mechanism involves not only the mechanical structure of the whole lamp but also the beautiful appearance of the lamp.
The heat dissipation performance of the heat sink is largely determined by the mechanical design of the heat sink. The material is the die-cast aluminum of ADC-12.
When the parameters such as the outer diameter of the heat sink, the height of the Fin sheet, and the density of the Fin sheet are different, the heat dissipation performance may be quite different. During the design process, we selected four different types of radiators for heat flow simulation.
In the simulation of the superheated flow, we found that Case4 has the best thermal performance.
So we can draw the following conclusions:
1. Lowering the Fin height while increasing the outer diameter of the Heat sink results in more efficient heat dissipation.
2. The same weight of the Heat sink, the increased height compared to the increase in the diameter of the radiator, the latter can achieve more effective heat dissipation.
6.0 LED optical design
LED High Bay Lighting compared with high-pressure sodium lamps or metal halide lamps, LEDs are used for factory lighting. Different light distributions are now available, and the same illumination can be achieved by different light distributions.