Computer hardware produces a huge amount of heat when operating. Usually this heat is removed by a combination of heatsinks and fans
The grey heatsink conducts the heat away from the processor and the sink’s fins give the heatsink a larger surface area for the air moved by the fan to blow over. Some computers use very large heatsinks in order to do away with the need for a fan entirely, relying only on natural convection currents for cooling.
Some computers do away with fans by pumping water past the heatsink; water is a much better absorber of heat than air* and therefore the system uses less power for cooling.
Green Revolution Cooling have gone one step further – they actually submerge the computing hardware in a special non-conductive liquid. This liquid then circulates, transferring the heat away to an external evaporation tower.
They claim that their cooling system will pay for itself within 1-3 years.
* The specific heat capacity of air is 1.007 joules per gram per kelvin and the specific heat capacity of water is 4.187 J/g/K. This means that water will absorb more than four times the energy of the same amount of air for the same increase in temperature. Green Revolution don’t say what the specific heat capacity of the fluid they use is, but it’s likely to be greater than water’s.