Liquid cooling is the reduction of heat in electronic and mechanical equipment by using the high heat absorption capacity of water. It is a proven cooling method in many current technologies. It is generally used in automobiles, mainframe computers and high-performance computer systems, with cooling methods and coolants varying depending on the application.
Functionality of water cooling systems
In computers, a closed cooling circuit is used for water cooling, which transports coolant from one component to another.
The processor and graphics card heat up the most when there is a high computing load in the PC. Blocks of water are screwed in. They are coated with copper or aluminium at the point of contact, so that the heat is absorbed and conducted into the water. In order to maximise heat dissipation, the water blocks are first coated with a heat-conducting paste made of a mixture of liquid metals such as tin, gallium and indium.
A pump transports the heated liquid from the water block to the radiator, where the water circulates through the cooling fins and cools down. The radiator thus takes over the function of the equalizing tank. The liquid is then pumped back into the water blocks. The coolant never comes into direct contact with the components.
Water cooling is often provided by fans. These transport the heat emitted by the cooling fins out of the computer casing. The larger the fan, the more hot air flows out of the case at a constant speed.
The coolant, which we used to call "water", consists of distilled water, cooling concentrate and other additives. It is odourless, non-flammable, protects the system from corrosion and is biodegradable.
Differentiation between types of water cooling
For water cooling, we distinguish between individually designed cooling systems and all-in-one (AiO) systems. Sophisticated water cooling systems are often visible on gaming PCs because, in addition to their cooling function, they can be staged very effectively thanks to transparent housing walls. They are combined with pipes or hoses, a pump, water blocks, radiator and compensating tank to form a closed circuit. The expansion tank is necessary because the water expands or contracts due to temperature. It prevents overpressure in the circuit. At the same time, the coolant is fed into the circuit via the equalizing tank.
These individually designed water cooling systems are complex to install, require sufficient space in the housing and require regular maintenance. There is some evaporation of the coolant in the equalizing tank, so the evaporated coolant must be replaced again.
AiO water cooling systems, on the other hand, are much smaller and more flexible. They do not block access to other PC components and are cheaper. Because they are compact and self-contained from the outset, they do not lose coolant and are maintenance-free. Complete solutions are suitable for systems where appearance is of secondary importance.
Advantages and disadvantages of water cooling
Water can absorb more heat than air, so water cooling systems cool better than pure fans. If the components are cooled more strongly, their service life increases. In addition, water cooling offers more peace of mind than air cooling. Although most water cooling systems also use fans, the noise level is much lower compared to conventional air cooling - an audible difference.
As a rule of thumb, the more fans and the larger the radiator, the quieter the cooling can run. But every water cooling system also needs its own space.
We have summarised the most important advantages and disadvantages in a table. We also make a distinction between individually composed water cooling systems and all-in-one systems.