The Heat sink is a common component found in various electrical and mechanical machines. It plays a very important role in the lifespan and work efficiency of these machines or devices. In this article, we will describe what is a heat sink, how does it work, and what aspects you should look for when buying one.
What is Heat Sink?
A heat sink is basically a type of heat exchanger that is used in various machines generating heat, mainly to decrease the temperature efficiently. It is a liquid cooling system that comes in many shapes and sizes according to the need.
While working, the internal temperature of a machine or a component can rise rapidly to the point where the part can even be damaged because of it. To prevent the damage due to extreme thermal conditions, the heat sink is applied. Overheating causes damages to several electrical devices components like laptops, motherboards, etc.
Where Can Be Found A Heat Sink?
Various types of machinery from small to large scale can be equipped with heat sinks. For example, in motor and vehicle radiators, chipsets, and especially in computers or laptops. They are used with the motherboards to cool the computer processors, also used with a graphics card, ram modules, and many more. These come with various costs and sizes for different needs.
Types of Heat Sink
There are various types of heat sinks for different needs. Depending on the airflow process, there are 3 general types:
- Active heatsink :
Here the air is forced towards the given direction with a blower or a fan. As a result, the airflow is better.
- Passive heatsink :
Here the heat exchange depends on natural convection. No fan is required but the flow rate is low.
- Hybrid heatsink :
These types combine both active and passive heatsinks for the best results.
For computers, the classification is different. The size of these heatsinks can be moderate to very small. There are also 3 types here:
- Heat spreader:
These are the most commonly used heatsinks that consist of a metal piece that dissipates heat to the surrounding environment. The advantage is the low space needed here, but the efficiency is lower.
- Finned heatsinks or passive pinned heatsinks:
This is also a type of heat spreader with some special structures that increase the surface area where heat can be dissipated. These are more efficient than heat spreader but the drawback is more space is needed here, and it is also an expensive option.
- Vapor chamber or heat pipe:
This is the most efficient and most expensive type that is used in very high-temperature environments like in CPUs and graphics cards
How Does a Heat Sink Work?
The mechanism of a heat sink is been described as follows:
These depend on a single metal piece to dissipate heat. The metal is often aluminum or copper. Copper is twice thermally conductive than aluminum but weighs more. The heat source is in contact with the metal piece, and the job of the metal piece is to transmit heat to the surrounding. As a result, the surface area of the surrounding can’t be increased here. These are the most basic heat sinks in use.
These are better than the heat spreaders because the metal piece comes with special structures that help increase usable surface area for heat dissipation, at a cost of space and materials. The result is more heat dissipation efficiency.
These are also used with an additional fan and called actively cooled heatsinks. The fan blows air towards the heatsink to ensure better heat exchange. These aren’t very expensive, and thus commonly used in computers.
Heat Pipe and Vapor Chambers
Heat pipe and vapor chambers work on the same principle with slight modification in structures. This is the most advanced type that works on the basis of a phase change to increase thermal conductivity significantly. The chamber is made with copper or aluminum which contains water that changes from liquid to gas and reverse. The low pressure inside allows the liquid to vaporize quicker at a lower temperature. The heat pipe contains wick inside the pipes that catch the liquid.
The phase changing allows them to transmit heat extremely fast from source to the fins. The working fluid transforms from liquid to gas due to the heat from the heat source. The gas travels to the other end of the chamber where it discharges heat to the atmosphere and cools down to the liquid. The process cycles endlessly.
The vapor chambers allow up to 700W of cooling capacity. It is lighter, highly efficient, and can be used in any orientation, even upside down. The only drawback is the heat transfer occurs in one direction only.
How to Improve Heat Sink Performance?
There are some steps that can ensure better efficiency and thermal capacity of heat sinks. These are:
- The surrounding (ambient) temperature should be lower. If the room temperature is low, the heatsinks can perform better. Airflow rich environments with open windows and lower temperatures will result in a much lower temperature of the target component.
- Better thermal interface material is required. The thermal interface material is a type of substance used between the two adjoining metal surfaces: the heat source and the metal piece of the heat spreader. This is used to minimize the free space between the metal surfaces. Using better thermal interface material causes better heat conduction and prevents trapping heat.
- Better airflow is vital. The performance of heatsink can simply be increased with more airflow. That’s why sometimes fans or blowers are used. They force more air to pass through.
- Anodized metal in heatsinks is better than the raw ones. The advantage of using anodized metals is a thicker oxide layer on metal surfaces that enhances radiation and also allows coloring the heatsinks.
- Better mounting is needed. Mountings ensure better contact between heatsinks and chips. Good solid mount causes effective transfer of heat and prevents air bubble trapping inside, and many more interferences. Various types of mountings include push pins and clips that require holes in a circuit board, epoxy, conductive tapes, etc.
Considerations While Buying a Heatsink
The main focus here is to improve thermal conduction. So, a bigger heatsink with more surface area for dissipation is often a better choice if there is space available in computers. For cooling vital components like processors, more efficient heatsinks are needed to handle the extreme environment and ensure a higher lifespan.
The material used in heatsinks is also a consideration. Typically, aluminum or copper is used here. While aluminum is 3 times lighter, copper is twice heat conductive than aluminum. Choose accordingly. The other features like RGB lightings and flashy visuals are really not worth spending extra money.
In this article, we’ve briefly overviewed what is heat sink and how does a heat sink work. Heatsinks are vital for the longevity of valuable components like processors and graphics cards. Following this article, you can choose the perfect type of heatsink to maximize the performance of your computers.