When using a computer, place your hand on the top or back of the device. You may notice that these areas are warmer than the ambient temperature. If you're using a typical desktop computer, you might also hear the hum of the internal fan as it blows hot air out and circulates cool air over the internal components.
What you're feeling and hearing is the computer's cooling system working continuously to prevent the computer processor from overheating, which could damage internal components.

Cooling is one of the most critical considerations in any computer design, and there are multiple solutions to this problem. The choice of solution by designers depends on the computer's intended use and its expected operating environment.

Why Do Computers Generate Heat?

The answer lies in electrical conductivity. All materials have a certain level of resistance, which refers to how easily electrons can pass through the material. The resistance of materials causes some electrical energy to be wasted in the form of heat. This is why superconductors, materials that can conduct electricity with zero loss, are so highly sought after.
However, until we achieve this goal, we can only continue to cool our computers.

The major heat sources in a computer are:

CPU and GPU: The Central Processing Unit (CPU) and Graphics Processing Unit (GPU) are among the components in a computer that operate at the highest temperatures. They perform millions of calculations per minute and are relatively small in size, meaning heat is more concentrated. Therefore, dedicated cooling devices are usually installed directly on the CPU and GPU.

• Battery: Laptops and tablets rely on batteries for power. These batteries are another source of heat as they store and distribute large amounts of electrical energy.
• Mechanical Hard Drives: Although solid - state drives are becoming increasingly popular for both consumer and enterprise use, mechanical hard drives are still widely used. Due to their spinning disks and mechanical readers, they generate heat.
• Consequences of Overheating

So, what happens when a computer starts to overheat? In the best - case scenario, you may be faced with an expensive computer repair or replacement bill. In the worst - case scenario, you may have to repair or replace any other equipment that has been damaged due to the computer malfunction. This equipment could be medical devices, Point - of - Sale (POS) systems, or those on an assembly line.
When a computer overheats, several things can occur. Most notably, if the CPU reaches a boiling point of 212°F or 100°C, it will automatically throttle its performance and slow down to prevent serious damage.
If this measure fails and the heat continues to rise, serious consequences will follow. At high temperatures, the solder connecting the circuits can melt, the silicon can crack, and the wires can become brittle and lose their insulation.

Types of Computer Cooling

Now that we understand the problem, what are the solutions? Almost every type of computer incorporates some form of cooling solution.
The most common types of cooling for computers are:

1. Fans: The most popular cooling method is using fans to blow hot air away from computer components and replace it with cool air from outside the case.

While fans are very popular in consumer-grade computers, they have several drawbacks: they are noisy, have reliability issues due to their reliance on moving parts, and they can spread dust and microorganisms throughout the operating environment.

This last point is a serious problem in any workplace where cleanliness is highly valued, such as a hospital ward or a clean room.

2. Liquid Cooling: Liquid cooling works similarly to air cooling, but it uses liquid as the medium. A liquid - cooling system installs a cooler on the heat source (such as the CPU) and uses a radiator to transfer heat from the processor to the liquid. The liquid is then pumped out of the radiator, cooled, and pumped back into the radiator in a continuous cycle.  

Although liquid cooling is very effective, it is expensive, requires specialized equipment inside the computer, and takes up a lot of space inside the PC, which can be a problem for applications that require a smaller size.

For these reasons, liquid cooling is usually only used for special purposes, such as dedicated servers or high - end gaming computers.

3. Fan - less Cooling: Last but not least, fan - less cooling. Also known as passive cooling, it relies on a heat sink to dissipate the heat generated by the processor into the air. The heat sink is connected to the heat source, absorbs the heat, and radiates it into the surrounding air.

These heat sinks are designed with the largest possible surface area so that they can dissipate a large amount of heat despite their relatively small size. 

The main advantages of fan-less cooling are that it doesn't require moving parts, doesn't consume power during operation, and doesn't produce any noise while dissipating heat.

For these reasons, fanless cooling is the most popular choice for dedicated medical computers and industrial-grade tablets.