Information about Water Cooled
Water cooling is a method of heat removal from components. As opposed to air cooling, water is used as the heat transmitter. Water cooling is commonly used for cooling internal combustion engines in automobiles and electrical generators. Other uses include cooling the lubricant oil of pumps; for cooling purposes in heat exchangers; cooling products from tanks or columns, and a bit more recently, cooling of various major components inside top-end personal computers. The main mechanism for water cooling is convective heat transfer.
Another less common chemical additive is products to reduce surface tension. These additives are meant to increase the efficiency of automotive cooling systems. Such products are used to enhance the cooling of underperforming or undersized cooling systems or in racing where the weight of a larger cooling system could be a disadvantage.
In the past few years, water cooling has become noticed for cooling computer components, especially the CPU. Water cooling usually consists of a CPU water block, a water pump and a heat exchanger (usually a radiator with a fan attached). Water cooling not only allows for quieter operation and improved overclocking, but with improved heat handling capabilities hotter processors can be supported. Less commonly, GPUs, Northbridges, hard drives, memory, VRM, and even power supplies are also water cooled.
Water coolers for computers (other than mainframes) were, up until the end of the 90's, homemade. They were put together using car radiators (or more commonly, a car's heater core), aquarium pumps and home made water blocks. In conjunction with these automotive items users would pair laboratory-grade PVC and Silicone tubing and various reservoirs (home made using plastic bottles, or constructed using cylindrical acrylic or sheets of acrylic, usually clear) and or a T-Line. More recently a growing number of companies are manufacturing pre-made, specialised components, allowing water cooling to be compact enough to fit inside a computer case. This, coupled with the growing amount of heat coming from the CPU has greatly increased the popularity of water cooling. However it is still a very niche market.
Dedicated overclockers will occasionally use vapor-compression refrigeration or thermoelectric coolers in place of more common standard heat exchangers. Water cooling systems in which water is cooled directly by the evaporator coil of a phase change system are able to chill the circulating coolant below the ambient air temperature (an impossible feat using a standard heat exchanger) and, as a result, generally provide superior cooling of the computer's heat-generating components. The downside of phase-change or thermoelectric cooling is that it uses much more electricity and antifreeze must be added due to the low temperature. Additionally, insulation, usually in the form of lagging around water pipes and neoprene pads around the components to be cooled, must be used in order to prevent damage caused by condensation of water vapour from the air on the surfaces at below ambient temperature. Common places from which to borrow the required phase change systems are a household dehumidifier or air conditioner.
An alternative cooling system, which enables components to be cooled below the ambient temperature, but which obviates the requirement for antifreeze and lagged pipes, is to place a thermoelectric device (commonly referred to as a 'Peltier junction' or 'pelt' after Jean Peltier, who documented the effect) between the heat-generating component and the water block. Because the only sub-ambient temperature zone now is at the interface with the heat-generating component itself, insulation is required only in that localized area. The disadvantage to such a system is that pelts typically draw a large amount of power, and the water cooling system is required to remove this power, in addition to the heat generated by the component. Another possible danger is condensation, resulting from the ambient air right around the pelt being cold. This condensation could cause a short-circuit, shutting the computer down or possibly permanent damage.
Apple's Power Mac G5 was the first mainstream desktop computer to have water cooling as standard, and Dell later followed suit by shipping their XPS computers with liquid cooling, using thermoelectric cooling to help cool the liquid.
Most industrial cooling towers use river water or well water as their source of fresh cooling water. The large mechanical induced-draft or forced-draft cooling towers in industrial plants such as power stations, petroleum oil refineries, petrochemical plants and natural gas processing plants continuously circulate cooling water through heat exchangers and other equipment where the water absorbs heat. That heat is then rejected to the atmosphere by the partial evaporation of the water in cooling towers where upflowing air is contacted with the circulating downflow of water. The loss of evaporated water into the air exhausted to the atmosphere is replaced by "make-up" fresh river water or fresh cooling water. Since the evaporation of pure water is replaced by make-up water containing carbonates and other dissolved salts, a portion of the circulating water is also continuously discarded as "blowdown" water to prevent the excessive build-up of salts in the circulating water.[1]
On very large rivers, but more often at coastal and estuarine sites, "direct cooled" systems are often used instead. These industrial plants do not use cooling towers and the atmosphere as a heat sink but put the waste heat to the river or coastal water instead. These "once-through" systems thus rely upon a good supply of river water or sea water for their cooling needs; the warmed water is returned directly to the aquatic environment. Thermal pollution of rivers, estuaries and coastal waters is an issue which needs to be addressed when considering the siting of such plants. Other impacts include "impingement" (the capture of larger organisms such as fish and shrimp on screens protecting the small bore tubes of the heat exchangers from blockage) and "entrainment" (the combined effects of temperature, pressure, biocide residual and turbulence/shear on smaller organisms entrained with the cooling water and then expelled back to the aquatic environment in the effluent). The cooling water in such heat exchange cycles is often treated with a biocide to prevent fouling in heat exchangers like condensers and other equipment, but in some instances such control can be exercised instead through frequent cleaning, antifouling paints (both toxic-release and non-toxic), or heat treatment.
High grade industrial water (produced by reverse osmosis) and potable water is sometimes used in industrial plants requiring high-purity cooling water.
Some nuclear reactors use heavy water as cooling. Most of the time, heavy water is employed in nuclear reactors because it is a moderator for the nuclear chain reaction. For the main cooling system, normal water is preferably employed through the use of a heat exchanger as heavy water is much more expensive. Reactors that use other materials for moderation (graphite) may also use normal water for cooling.
Advantages
The advantages of using water cooling over air cooling include water's higher specific heat capacity, density and thermal conductivity. This allows water to transmit heat over greater distances with much less volumetric flow and reduced temperature difference. For cooling CPU cores, this is its primary advantage: the tremendously increased ability to transport heat away from source to a secondary cooling surface allows for large, more optimally designed radiators rather than small, inefficient fins mounted on or near a heat source such as a CPU core. The "water jacket" around an engine is also very effective at deadening mechanical noises, which makes the engine quieter.Open method
An open water cooling system makes use of evaporative cooling, lowering the temperature of the remaining (unevaporated) water. A component such as a bong cooler replaces the radiator of a closed water cooling system. The obvious downside of this method is the need to continually replace the water lost due to evaporation.Automotive usage
The use of water cooling carries the risk of damage from freezing. Automotive and many other engine cooling applications require the use of a water and antifreeze mixture to lower the freezing point to a temperature unlikely to be experienced. Antifreeze also inhibits corrosion from dissimilar metals and can increase the boiling point, allowing a wider range of water cooling temperatures. Its distinctive odor also alerts operators to cooling system leaks and problems that would go unnoticed in a water-only cooling system.Another less common chemical additive is products to reduce surface tension. These additives are meant to increase the efficiency of automotive cooling systems. Such products are used to enhance the cooling of underperforming or undersized cooling systems or in racing where the weight of a larger cooling system could be a disadvantage.
Computer usage
- See also:
)
Interior of a water cooled computer, showing CPU/GPU waterblock, tubing and pump
)
DIY Watercooling setup showing Laing Thermotech D4 12v pump, Swiftech STORM CPU Waterblock and the typical application of a T-Line
Water coolers for computers (other than mainframes) were, up until the end of the 90's, homemade. They were put together using car radiators (or more commonly, a car's heater core), aquarium pumps and home made water blocks. In conjunction with these automotive items users would pair laboratory-grade PVC and Silicone tubing and various reservoirs (home made using plastic bottles, or constructed using cylindrical acrylic or sheets of acrylic, usually clear) and or a T-Line. More recently a growing number of companies are manufacturing pre-made, specialised components, allowing water cooling to be compact enough to fit inside a computer case. This, coupled with the growing amount of heat coming from the CPU has greatly increased the popularity of water cooling. However it is still a very niche market.
Dedicated overclockers will occasionally use vapor-compression refrigeration or thermoelectric coolers in place of more common standard heat exchangers. Water cooling systems in which water is cooled directly by the evaporator coil of a phase change system are able to chill the circulating coolant below the ambient air temperature (an impossible feat using a standard heat exchanger) and, as a result, generally provide superior cooling of the computer's heat-generating components. The downside of phase-change or thermoelectric cooling is that it uses much more electricity and antifreeze must be added due to the low temperature. Additionally, insulation, usually in the form of lagging around water pipes and neoprene pads around the components to be cooled, must be used in order to prevent damage caused by condensation of water vapour from the air on the surfaces at below ambient temperature. Common places from which to borrow the required phase change systems are a household dehumidifier or air conditioner.
An alternative cooling system, which enables components to be cooled below the ambient temperature, but which obviates the requirement for antifreeze and lagged pipes, is to place a thermoelectric device (commonly referred to as a 'Peltier junction' or 'pelt' after Jean Peltier, who documented the effect) between the heat-generating component and the water block. Because the only sub-ambient temperature zone now is at the interface with the heat-generating component itself, insulation is required only in that localized area. The disadvantage to such a system is that pelts typically draw a large amount of power, and the water cooling system is required to remove this power, in addition to the heat generated by the component. Another possible danger is condensation, resulting from the ambient air right around the pelt being cold. This condensation could cause a short-circuit, shutting the computer down or possibly permanent damage.
Apple's Power Mac G5 was the first mainstream desktop computer to have water cooling as standard, and Dell later followed suit by shipping their XPS computers with liquid cooling, using thermoelectric cooling to help cool the liquid.
Industrial usage
)
A Marley mechanical induced draft cooling tower
High grade industrial water (produced by reverse osmosis) and potable water is sometimes used in industrial plants requiring high-purity cooling water.
Some nuclear reactors use heavy water as cooling. Most of the time, heavy water is employed in nuclear reactors because it is a moderator for the nuclear chain reaction. For the main cooling system, normal water is preferably employed through the use of a heat exchanger as heavy water is much more expensive. Reactors that use other materials for moderation (graphite) may also use normal water for cooling.
See also
- Air cooling
- Oil cooling
- Computer cooling
- Cooling tower
- Cooling tower system
- Engine cooling
- Heat pipe cooling
- Peltier cooling
- Thermosiphon
- Deep lake water cooling
- Heater Core
References
1. ^ Beychok, Milton R. (1967). Aqueous Wastes from Petroleum and Petrochemical Plants, 1st Edition, John Wiley and Sons. LCCN 67019834. (See Chapter 2 for material balance relationships in a cooling tower)
External links
- Liquid Cooling 101
- Beginners guide to PC Watercooling
- A 'green' Antifouling alternative to Chlorine
- Water Cooling 101
- Water Cooling Guide
- Basic Theory and Practice of Cooling Towers
- Howstuffworks "How Liquid-cooled PCs Work"
- Water Cooling 101 Site
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Air cooling is one method of dissipating heat. It works by making the object to be cooled have a larger surface area or have an increased flow of air over its surface, or both.
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Water is a common chemical substance that is essential to all known forms of life.[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. This exothermic reaction creates gases at high temperature and pressure, which are permitted to expand.
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automobile (from Greek auto, self and Latin mobile moving, a vehicle that moves itself rather than being moved by another vehicle or animal) or motor car (usually shortened to just car) is a wheeled passenger vehicle that carries its own motor.
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A lubricant (colloquially, lube) is a substance (often a liquid) introduced between two moving surfaces to reduce the friction and wear between them. A lubricant provides a protective film which allows for two touching surfaces to be separated, thus lessening the friction
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pump is a device used to move liquids or slurries. A pump moves liquids from lower pressure to higher pressure, and overcomes this difference in pressure by adding energy to the system (such as a water system).
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A heat exchanger is a device built for efficient heat transfer from one fluid or gas to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are directly contacted.
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personal computer (PC) is a computer whose original sales price, size, and capabilities make it useful for individuals.
It is unknown who coined the phrase with the intent of a small affordable computing device but John W.
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It is unknown who coined the phrase with the intent of a small affordable computing device but John W.
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Convective heat transfer is a mechanism of heat transfer occurring because of bulk motion (observable movement) of fluids. This can be contrasted with conductive heat transfer, which is the transfer of energy molecule by molecule through a solid or fluid, and radiative heat
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Air cooling is one method of dissipating heat. It works by making the object to be cooled have a larger surface area or have an increased flow of air over its surface, or both.
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Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the temperature of a unit quantity of a substance by a certain temperature interval.
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thermal conductivity, k, is the property of a material that indicates its ability to conduct heat. It is used primarily in Fourier's Law for heat conduction.
It is defined as the quantity of heat, ΔQ, transmitted during time Δt
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It is defined as the quantity of heat, ΔQ, transmitted during time Δt
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central processing unit (CPU), or sometimes simply processor, is the component in a digital computer capable of executing a program.(Knott 1974) It interprets computer program instructions and processes data.
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Radiators and convectors are types of heat exchangers designed to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics.
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Evaporative cooling is a physical phenomenon in which evaporation of a liquid, typically into surrounding air, cools an object or a liquid in contact with it. Latent heat describes the amount of heat that is needed to evaporate the liquid; this heat comes from the liquid itself and
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A bong cooler or evaporative cooling tower is a bong-shaped device that is able to cool water to temperatures below room temperature (sub-ambient) via evaporative cooling. Its primary use is in computer cooling.
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Radiators and convectors are types of heat exchangers designed to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics.
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Antifreeze is used in internal combustion engines, and for many other heat transfer applications, such as electronics cooling and chillers for HVAC. Compounds are added to water to reduce the freezing point of the mixture to below the lowest temperature that the system is likely to
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central processing unit (CPU), or sometimes simply processor, is the component in a digital computer capable of executing a program.(Knott 1974) It interprets computer program instructions and processes data.
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A water block is the watercooling equivalent of a heatsink. It can be used on many different computer components including the central processing unit (CPU), GPU, and Northbridge chipset on the motherboard.
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pump is a device used to move liquids or slurries. A pump moves liquids from lower pressure to higher pressure, and overcomes this difference in pressure by adding energy to the system (such as a water system).
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A heat exchanger is a device built for efficient heat transfer from one fluid or gas to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are directly contacted.
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Radiators and convectors are types of heat exchangers designed to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics.
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Overclocking is the process of forcing a computer component to run at a higher clock rate than it was designed for or was designated by the manufacturer.
Overclocking is usually practiced by PC enthusiasts in order to increase the performance of their computers.
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Overclocking is usually practiced by PC enthusiasts in order to increase the performance of their computers.
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graphics processing unit or GPU (also occasionally called visual processing unit or VPU) is a dedicated graphics rendering device for a personal computer, workstation, or game console.
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The north bridge, also known as the memory controller hub (MCH) in Intel systems (AMD, VIA, SiS and others usually use 'northbridge'), is traditionally one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge.
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Hard disk drive
An IBM hard disk drive with the metal cover removed. The platters are highly reflective.
Date Invented: September 13 1956
Invented By: An IBM team led by Reynold Johnson
Connects to:
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An IBM hard disk drive with the metal cover removed. The platters are highly reflective.
Date Invented: September 13 1956
Invented By: An IBM team led by Reynold Johnson
Connects to:
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Dynamic RAM (DRAM) modules
Two 512 MB DRAM Modules
Connects to:
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Two 512 MB DRAM Modules
Connects to:
- PCB or motherboard via one of
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voltage regulator module or VRM, sometimes called PPM (power processing module) is an electronic device that provides a microprocessor the appropriate supply voltage. It can be soldered to the motherboard or be an installable device.
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