What are the factors that affect LED thermal performance?

When trying to get the most use of your LEDs lighting system in different industrial sectors, there are many significant impact that affect the performance of LED light, such as raw material and the working environment. In this blog, we’ll discuss some of the key factors that can have an impact on the performance of LED lights as well as show you some considerations on how to properly use that.

What is the LED Aluminum heat sink?

The heat sink is the most critical part of the LED lighting system, which is so-called as a heat exchanger or thermal management system for distributing the heat generated by the LED lamp into the surrounding air, so as to regulate its operating temperature.

What are the ways to dissipate heat?

Mainstream ways for heat dissipation are as follows:

Active Cooling:

This measure will cause a huge noise for which the heat sink fans are utilized as a heat sink. Meanwhile, you might acknowledge that as the fan is used for a longer period, the lubricant will become less, which will damage the working parts of the machine. On the contrary, featuring outstanding heat dissipation, it mainly use in LEDs street lights, mining lights, or high-power machinery (eg. CNC machine tools).

Passive Cooling

Avoid using fans for heat dissipation and featuring smooth operation. Therefore, Passive cooling has a straightforward working principle without any maintenance while featuring poor thermal management and dissipation.

Why do need LED heat sink?

Firstly, Let’s clarify the range of high-power and low-power LEDs, of which the former is 0.05 W with a current of 20 mA while LEDs with high power reach 1-10W with a current of 10-100 mA. Since high-power LEDs generate a lot of heat, this may damage itself and shorten their life.

The heat it generates is transferred to the fins of the aluminum heat sink where the heat will dissipate from the LED light source.

What factors that affect the performance of LED?

We should illustrate 3 concepts first before going forward: Conduction, Convection and Radiation.

Conduction

The LED chip is mounted on a metal substrate (0.25-0.35mm). It will conduct the heat to the metal substrate by thermal conduction and transfers the heat to the ambient air or surface area through a solder layer or heat transfer oil. This process follows the principle of heat transfer from a high-temperature object to a low one.

Convection

The process that transfers the heat by liquid or gas. For example, you can feel the temperature of hot soup in your hands.

Radiation

The heat is emitted straight outward from the source. For example, LED outputs light by generating visible light and infrared waves. Although the LED lamp itself does not produce a lot of heat, the infrared waves will increase its temperature.

Types of Aluminum Heat Sink

Extruded Heat Sinks

It is the most common heat sink featuring easy production and low manufacturing cost for low-power led lighting

Die Cast Heat Sink

The principle of the die casting is that heat sinks fill the mold cavity with molten aluminum alloy under high pressure to form a stronger structure than extrusion heat sinks. The thermal conductivity is 70-90W/ mK.

Cold Forging and Hot Forging Heat Sinks

It is made by compressing aluminum or copper with remarkable heat conductivity, a wide range of materials, ideal thermal structure and light weight except for its high cost.

Stamping Aluminum Heat Sink

Heat sinks are made by stamping machines and then weld to the base. It mainly uses for low-power led lighting featuring easy production, and low cost but underperformance.

Materials

A suitable material also plays a crucial role in effective thermal management, which means that manufacturer should choose a material by considering its thermal resistance, corrosion resistance and strength. If you choose aluminum alloy to manufacture heat sinks, you should contemplate what mixture you can add to the aluminum so as to meet your requirement.

Power of Heat Sinks

The power of heat sinks also affects their thermal conductivity. Typecially, high-power heat sinks feature well thermal management, which means that you should choose the right heat sink in accordance with your requirement. For example, you should choose a 100 W heat sink if you own a light with 100 W. Meanwhile, don’t increase the power of heat sinks because it is likely to reduce their life for generating more thermal energy.

Operating Voltage

If the LED is powered by a low voltage, it will not reach its full potential and vice versa, which means that we should pay attention to the range of operating voltage. For example, if the operating voltage is 12v, we should choose led heat sinks with the same voltage.

Thermal Conductivity

Thermal conductivity depends on fins and material, which means that a led heat sink with outstanding performance can dissipate the heat rapidly.

Hence, We should choose a led heat sink based on its well thermal management. For example, We should choose a thermal conductivity with 100 W as we own a led light output with the same.

Size of LED Light

LEDs is complicated to reach its potential without a high-power light output and vice versa. So, we recommend that your led module can perform well in the size of 0.125 – 0.25 mm.

Ambient Temperature

Low temperature proves the underperformance of lamp. Conversely, the light is likely to damage with high temperature. According to the latest research, we suggest adjusting its working temperature between -40 and +80 °C; or the light will be defective beyond 100 °C.

Junction Temperature

It represents the inner temperature of semiconductors. High junction temperatures means low-performance LED.

We should mention that junction temperature is regulated by two factors: power dissipation and thermal resistance, of which the power dissipation is determined by its design and the current flowing and the thermal resistance is affected by the type of LED, the size and shape of the LED heat sink, the connection between the operating component and the led heat sink as well as the ambient environment.

Generally speaking, the manufacturer regulates its maximum high junction temperature. Therefore, your LED may be damaged over the regulated junction temperature.

If you have any questions, please contact LED heat sink manufacturer for requesting relevant data to make a comparison to your LED.

Frequency of use

As the LED light source will generate a little heat, it will damage the LED light when using frequently without dissipating enough heat.

Therefore, We suggest LED lights are best used no more than 12 hours a day for ensuring the best performance and need to maintain the LED heat sink after turning off.

Parameter of LED Heat Sinks

The performance of aluminum heat sinks is dependent on its number, diameter and spacing between two fins. Typically, an LED heat sink with thinner fins is likely to surpass another heat sink with thicker ones.

Moreover, adding more fins does not improve its cooling performance in that it reduces the surface area between them, causing ambient air cannot flow between the fins.

Conclusion

We should acknowledge that light decay is inevitable. But we can extend its operating life by using optimal LED heat sink. Simultaneously, you should be aware of avoding increasing temperature and make a protection against moisture and rainproof. Meanwhile, follow suggestion we mention in that blog.

If you have any questions about LED heat sink and thermal system, please check out the link below:

https://www.kx-aluminum.com/info/attention-of-led-light-33308223.html