Laptop cooling system exhaust grill We are sometimes asked why eTray laptop trays don’t have built in fans like some laptop coolers do.

The short and simple answer is that we do not fit fans because our experiments have shown that they are neither necessary nor effective. If it is working properly, the laptop’s built in cooling system will do an excellent job of keeping the laptop cool and blowing air on the outside of a laptop will make little difference to the cooling of the laptop’s internal parts.

The only real exception to this is in cases where the laptop fan has failed and it is possible to locate an external  fan so that air is blown directly through the machine’s cooling system. This will help keep the machine going until it can be repaired, but it is only a temporary solution.

So, if you are having a problem with your laptop overheating then that usually indicates that some maintenance work is required. If that sounds alarming then let me reassure you: the solution may be much simpler than you think.

How laptop’s built-in coolers are designed

The fact is that the laptop PCs produced by top manufacturers are designed by some of the world’s best engineers. They know that the laptop’s processor and other parts generate heat when they operate and, because of this, they provide the machine with a carefully designed, highly efficient cooling system.

When laptop design engineers specify the components they will use for a new laptop design, one of the first things they do is to calculate exactly how much heat those components will produce when operating.

The result of this calculation tells the laptop designer exactly how much air the laptop’s cooling system will have to blow through the laptop to dissipate that heat. From this, they can calculate how big the fan needs to be and what size and shape the internal parts of the cooling system needs to be to remove that heat.

Laptop designers also know that sometimes that ambient air temperature can be high, the cooling system air intakes can get partially blocked, and that some applications like games can cause the computer to work harder than normal and consequently produce more heat. Because of this, they will add some extra capacity to the cooling system to make sure that it can cope.

The point is that laptop cooling systems are carefully designed to do the job that they need to do. New laptops rarely overheat unless they have a manufacturing fault. If overheating becomes a problem then it does so gradually over time – and there is a very good reason for that.

How laptop cooling systems work

Acer laptop cooling system showing fan and heat pipeNot many people realise that a laptop’s cooling system doesn’t simply blow air through the inside of the laptops casing. In fact, it is much more sophisticated than that. The laptop cooling system is precisely designed to cool the main heat generating parts of the machine. This is usually the CPU or main processor and sometimes the GPU – the graphics processor.

To do this a device known as a heat pipe is used. You may have noticed it if you have ever opened your laptop up. They can vary in shape but in the picture it is the bright copper component that looks a bit like a piece of plumbing.

You may have thought as I did that this is simply a length of conductive metal that is there to act as a heat sink. In fact, it is a cleverly designed heat pump that works on a principle similar to a gas refrigerator to actively cool the component it is attached to.

The heat pipe contains a liquid and a wicking structure that runs the length of the pipe. As it is heated by the CPU the liquid evaporates, absorbing heat and cooling the CPU. The vaporised liquid travels to the heat sink end of the pipe which is being cooled by the fan where it condenses back into liquid, giving up the heat it absorbed from the CPU. Capillary action then causes the liquid to return to the other end of the pipe via the wick. As the fluid circulates continuously it removes heat from the components and dumps it to the air via the heat sink.

Why laptops overheat

If all this is true, and the engineer’s are so smart, then you may be wondering why it is that laptops ever overheat. The fact is that there are two things that engineers can’t control. One is the way that you use your machine; the other is the amount of dust and dirt in the world.

The reason that most laptop cooling systems gradually become less effective is often due to the way that the laptop is used. If it is in a domestic environment with upholstery or cushions and carpet then the cooling system will continuously suck up particles of dust, fluff and dirt as it operates.

These become electrically charged as they make their way through the hot and dry interior of the laptop. The particles gradually accumulate inside the machine, particularly around the narrow fins on the heat sink. As they build up they form in to a thick, felt like material, which gradually reduce the cooling system’s ability to remove heat from the laptop and, eventually, overheating begins.

Once this has happened, no amount of air blown on the outside of the device will keep it cool. The only solution is to clean out the cooling system so that it can begin to operate properly again.

So, the reason that we don’t fit fans to eTray laptop trays is because we don’t think they are a good or effective solution to the problem of an overheating laptop. If you keep your laptop’s cooling system free of obstructions (by using on a flat surface such as a laptop tray) and the laptop overheats, then your machine has a cooling system fault.

Either there is an real fault such as a fan failure, or (more likely), the cooling system has become blocked up with dust and dirt over time. In either case you simply need to fix this problem to get your laptop running the way it did when it was new.

Over the next few posts I am going to explain how to diagnose a laptop’s overheating problem and, after that, how to fix it without getting a big repair bill.

Next post – Part Two: How to identify laptop overheating problems.

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