Why Water Cooling?

Water is about 20 times more efficient than air at removing the heat from a computer. Water holds 4 times more heat than air, weight for weight, but water has a higher density than air by around 1000 times. So a very small amount of water can hold much more heat energy compared to a large volume of air. This results in the ability to run component temperatures a lot closer to ambient, typically around 40C, with little temperature change under varying heat loads.

The System

A water cooling system (or loop) consists of:

• Water blocks
• Reservoir
• Pump
• Radiator
• Tubing
• Fittings
• Coolant

Basically the pump drives the coolant through the water blocks, to absorb the waste heat, and into the radiator where the waste heat is passed to the air. The coolant then flows to the reservoir and back to the pump to complete the circuit.

Water blocks

A water block commonly consists of at least two main parts, the "base", which is the part that makes contact with the device being cooled, usually made of a high conductivity metal such as aluminium or copper. The second part, the "top" ensures the water is contained safely inside the "block" and allows the attachment of fittings to connect the tubing to link it with the rest of the water cooling loop.

Reservoir

A reservoir simply holds extra coolant to compensate for the evaporation of the liquid in the loop. Sometimes the reservoir is combined with a pump which is submerged in the coolant.

Pump
The pump is required to force the coolant around the loop and is normally a 12v volt centrifugal magnetic drive type pump. This type of pump actually uses the coolant to provides bearing support so if there is no liquid the pump cannot run.

Radiator
The radiator or heat exchanger disperses the waste heat to the air. There are two types of radiator used. The ''flat tube" design has flat tubes and fins running between two tanks. This is the most efficient design. The other variety is the "coiled tube and fin" design. This has a continuous coiled tube with fins attached. Most often fans are fitted to the radiator to increase airflow over the fins and in turn increasing the rate of heat dispersion.

Tubing
The tubing is normally made from PVC or rubber. It must be durable and bend easily without kinking. Kinking restricts the flow of the coolant and slows the rate at which the coolant moves around the loop. If there is a danger of kinking anti kink coils are fitted around the tubing to prevent kinking.

Fittings
There are a few different types of fittings in different sizes Barbs, Push & Compression fittings. The key to avoiding any leaks is in the quality of the fittings. Compression tending to be the most reliable but they are also the most costly.

Coolant
There are number types of coolant starting from simple distilled water. Some have additive in them like UV dies, corrosive inhibiters and a number of coolant types are nonconductive which means your computer will survive if you experience a leak.

In the end that’s all there is to it but you can also add any number of accessories to your loop like a flow meter or a temperature sensor. Water-cooling a computer is not very difficult but it will require care and attention to be taking during the build and doing a bit of planning and research before you start will pay dividends on the end result.