In computers, water cooling is a method used to lower the temperatures of computer processors, and sometimes other components such as graphics cards, using water rather than air as the cooling medium. Processor speeds have increased dramatically in recent years. As a result, the heat given off by processors has also increased, as has the noise associated with equipment, such as fans, used to keep them running at a safe temperature. Because water can conduct heat about 30 times faster than air can, a water cooling system allows the processor to run at higher speeds while drastically reducing system noise. Some industry experts predict that water cooling systems will become standard for personal computers in the near future.
Here's a simple example of a water cooling system: A pump circulates the water through a water block (a device similar to a heat sink) attached to the processor; there, heat from the processor transfers to the water. The heated water continues on to a radiator at the back of the computer case and is replaced with cool water. The heat from the water in the radiator dissipates into the air surrounding the computer. When the water has cooled to the ambient temperature, it is cycled through the system again.
Water cooling is increasingly used to deal with the special requirements of the data center. Because data centers are often assigned the most convenient available space, rather than a space that is specially designed, servers may be contained in too small an area or one that cannot be adequately ventilated. Furthermore, some data center technologies, such as blade servers (which are densely structured), put increased stress on the data center's cooling system.
Water cooling brings its own issues to the data center, however, as well as benefits. Additional plumbing is often required. Water cooling can limit the flexibility of data center design because systems connected to plumbing cannot be easily rearranged. The combination of electronic systems and water also complicates disaster recovery planning (DRP). For example, administrators need to know in advance how they will deal with potential problems, such as rust or leakage. A common fear of combining electrical systems and water is another road block to acceptance of water cooling.
Despite the inherent challenges, many industry experts predict that water cooling is the inescapable future of the data center. According to Robert E. McFarlane, president of the Interport Division of New York-based Shen, Milsom and Wilke Inc., "Paranoia is the reason there's so little water-cooled equipment on the market. We tend to get married to the technologies that we know and are comfortable with, but it's getting to that point where you just can't cool these densities without carrying it in liquid form."
Water cooling is nothing new -- automobiles and mainframe computers have used water cooling systems for many years. However, water cooling is being used in some new and innovative applications, such as environmentally friendly air conditioning systems for buildings.
Water cooling is sometimes referred to as liquid cooling, because various other substances are sometimes used instead of, or in addition to, water.
Watch a video from Tom's Hardware about water cooling: