Contenido

Pocas aplicaciones de refrigeración se acercan a los grandes volúmenes de agua necesarios para condensar el vapor a baja presión de las centrales eléctricas.[20]​ Muchas instalaciones, sobre todo centrales eléctricas, utilizan millones de litros de agua al día para la refrigeración.[21]​ La refrigeración por agua a esta escala puede alterar los entornos acuáticos naturales y crear otros nuevos. La contaminación térmica de ríos, estuarios y aguas costeras es un factor a tener en cuenta a la hora de ubicar este tipo de centrales. El agua devuelta a los entornos acuáticos a temperaturas superiores a las del agua receptora ambiente modifica el hábitat acuático al aumentar las tasas de reacción bioquímica y disminuir la capacidad de saturación de oxígeno del hábitat. Los aumentos de temperatura favorecen inicialmente un cambio de población de las especies que requieren la alta concentración de oxígeno del agua fría a las que disfrutan de las ventajas de las mayores tasas metabólicas del agua caliente.[9]​.

Los sistemas de refrigeración de un solo paso (OTC) pueden utilizarse en ríos muy grandes o en emplazamientos costeros y estuarinos. Estas centrales vierten el calor residual en el agua del río o de la costa. Por lo tanto, estos sistemas dependen de un buen suministro de agua de río o de mar para sus necesidades de refrigeración. Estas instalaciones se construyen con estructuras de toma diseñadas para bombear grandes volúmenes de agua a un caudal elevado. Estas estructuras suelen arrastrar también un gran número de peces y otros organismos acuáticos, que mueren o resultan heridos en las rejillas de admisión.[22]​ Los grandes caudales pueden inmovilizar a los organismos de natación lenta, incluidos los peces y las gambas "Gamba (crustáceo)"), en las rejillas que protegen de la obstrucción los tubos de pequeño diámetro de los intercambiadores de calor. Las altas temperaturas o la turbulencia y el cizallamiento de la bomba pueden matar o inutilizar a los organismos más pequeños que pasan por las rejillas arrastrados por el agua de refrigeración.[23]​ Más de 1.200 centrales eléctricas y fabricantes utilizan sistemas OTC en EE. UU.[24]​ y las estructuras de admisión matan miles de millones de peces y otros organismos cada año.[25]​ Los depredadores acuáticos más ágiles consumen los organismos atrapados en las rejillas; y los depredadores y carroñeros de aguas cálidas colonizan la descarga de agua de refrigeración para alimentarse de los organismos arrastrados.

La Ley de Agua Limpia de EE. UU. requiere que la Agencia de Protección Ambiental (EPA) emita regulaciones sobre las estructuras de toma de agua de refrigeración industrial.[26]​ La EPA emitió regulaciones finales para nuevas instalaciones en 2001 (modificadas en 2003),[27]​ y para instalaciones existentes en 2014.

cooling towers

As an alternative to OTC, industrial cooling towers can use recirculated river water, coastal water (seawater), or well water. Large mechanical induced or forced draft cooling towers in industrial plants continuously circulate cooling water through heat exchangers and other equipment in which the water absorbs heat. That heat is then expelled to the atmosphere through the partial evaporation of water in cooling towers, where rising air comes into contact with the downward flow of circulating water. The loss of evaporated water in the air that is expelled to the atmosphere is replaced by fresh "makeup" river water or fresh cooling water; but the volumes of water lost during evaporative cooling can decrease the natural habitat of aquatic organisms. Since the evaporation of pure water is replaced by makeup water containing carbonates and other dissolved salts, a portion of the circulating water is also continuously discarded as "bleed" water to prevent excessive salt buildup in the circulating water; and these blowdown residues can change the quality of the receiving water.[28]​.

La camisa de agua que rodea un motor es muy eficaz para amortiguar los ruidos mecánicos, lo que hace que el motor sea más silencioso.

Open method

An open water cooling system uses evaporative cooling, reducing the temperature of the remaining (non-evaporated) water. This method was common in early internal combustion engines, until scale buildup of dissolved salts and minerals in water was observed. Modern open cooling systems continuously discard a fraction of the recirculation water as blowdown to remove dissolved solids at concentrations low enough to prevent scale formation. Some open systems use cheap tap water, but this requires higher purge rates than deionized or distilled water. Purified water systems still require purging to remove buildup of chemical treatment byproducts and prevent corrosion and biofouling.[7]​.

Pressurization

Water cooling also has a boiling point temperature of around 100 degrees C at atmospheric pressure. Engines operating at higher temperatures may require a pressurized recycle circuit to prevent overheating.[29] Modern automotive cooling systems typically operate at 15 psi (103 kPa) to raise the boiling point of the recycle water coolant and reduce evaporation losses.[30]

Antifreeze

Using water cooling carries the risk of freeze damage. Automotive and many other engine cooling applications require the use of a mixture of water and antifreeze to reduce the freezing point to an unlikely temperature. Antifreeze also inhibits the corrosion of dissimilar metals and can increase the boiling point, allowing a wider range of water cooling temperatures.[31] Its characteristic odor also alerts users to leaks and problems in the cooling system that would go unnoticed in a water-only cooling system. The heated coolant mixture can also be used to heat the air inside the car using the heater core.

Other additives

Other less common chemical additives are products to reduce surface tension. These additives are intended to increase the efficiency of automobile cooling systems. Such products are used to improve cooling of low-performance or undersized cooling systems or in racing where the weight of a larger cooling system could be a disadvantage.

Liquid cooling maintenance

Liquid cooling techniques are increasingly used for thermal management of electronic components. This type of cooling is a solution to ensure optimization of energy efficiency while minimizing noise and space requirements. Especially useful in supercomputers or Data Centers, since rack maintenance is quick and simple. Once the rack is disassembled, the advanced technology quick couplings eliminate spills for greater operator safety and protect the integrity of the fluids (no impurities in the circuits). In electronic technology it is important to analyze the connection systems to guarantee:

Water cooling typically adds complexity and cost compared to air-cooled design, as it requires a pump, tubes or pipes to transport the water and a radiator, often with fans, to exhaust heat to the atmosphere. Depending on the application, water cooling can create an additional element of risk, as leaks from the coolant recycle circuit can corrode or short-circuit sensitive electronic components.

The main advantage of water cooling for cooling CPU cores in computing equipment is that it transports heat from the source to a secondary cooling surface, allowing large, optimally designed radiators to be used instead of small, relatively inefficient fins mounted directly above the heat source. Cooling hot computer components with various fluids has been used at least since Cray-2 in 1982, with Fluorinert. Throughout the 1990s, water cooling for home PCs slowly gained recognition among enthusiasts, but became noticeably more prevalent following the introduction of the first gigahertz clocked processors in the early 2000s. As of 2018, there are dozens of manufacturers of water cooling components and kits, and many computer manufacturers include pre-installed water cooling solutions for their high-performance systems.

Water cooling can be used to cool many computer components, but is typically used for the CPU and GPU. Water cooling generally uses a water block, a water pump, and a water-to-air heat exchanger. By transferring heat from the device to a separate heat exchanger, which can be larger in size and use larger, lower speed fans, water cooling can allow for quieter operation, improved processor speed (overclocking), or a balance of both. Less commonly, Northbridges, Southbridges, hard drives, memory, voltage regulator modules (VRMs), and even power supplies can be water cooled.[32]​.

The size of the internal radiator can vary: from 40 mm with dual fans (80 mm) to 140 with quad fans (560 mm) and the thickness from 30 mm to 80 mm. Radiator fans can be mounted on one or both sides. External radiators can be much larger than their internal counterparts, as they do not need to fit in the confines of a computer case. Higher-end cases may have two ports with rubber grommets on the back for inlet and outlet hoses, allowing external radiators to be placed away from the PC.

Specialized overclockers have occasionally used vapor compression cooling or thermoelectric coolers instead of the more common standard heat exchangers. Water cooling systems, in which water is cooled directly by the evaporator coil of a phase change system, are capable of cooling the circulating coolant below the ambient air temperature (impossible with a standard heat exchanger) and, as a result, typically provide superior cooling of the computer's heat-generating components. The disadvantage of phase change or thermoelectric cooling is that it consumes much more electricity and, due to the low temperature, antifreeze must be added. Additionally, to prevent damage caused by condensation of water vapor in the air on cooled surfaces, insulation must be used, typically in the form of heat insulation around water pipes and neoprene pads around components to be cooled. A home dehumidifier or air conditioner are common places to borrow the necessary phase transition systems.[33]​.

Water is an ideal cooling medium for ships, as they are constantly surrounded by water that is generally kept at a low temperature throughout the year. Systems that operate with seawater should be made of cupro-nickel, bronze, titanium or similar corrosion-resistant materials. Water containing sediment may require velocity restrictions through pipes to prevent high-velocity erosion or blockage by low-velocity sedimentation.[34]​.

Plant transpiration and animal transpiration use evaporative cooling to prevent high temperatures from causing unsustainable metabolic rates.

Machine guns used in fixed defensive positions sometimes use water cooling to extend barrel life during periods of rapid fire, but the weight of the water and pump system greatly reduces the portability of water-cooled firearms. Water-cooled machine guns were widely used by both sides during World War I, but towards the end of the war lighter weapons began to appear on the battlefield that rivaled the firepower, effectiveness and reliability of water-cooled models, so these weapons have played a much smaller role in later conflicts.

A Swedish hospital uses meltwater to cool its data centers and medical equipment and maintain a comfortable room temperature.[35]​.

Some nuclear reactors use heavy water for cooling. Heavy water is used in nuclear reactors because it is a weaker neutron absorber. This allows the use of less enriched fuel. For the main cooling system, normal water is preferably used through the use of a heat exchanger, since heavy water is much more expensive. Reactors that use other materials for moderation (graphite) can also use normal water for cooling.

High-quality industrial water (produced by reverse osmosis or distillation) and drinking water are sometimes used in industrial plants that require high-purity cooling water. The production of these high-purity waters generates residual by-product brines that contain the concentrated impurities of the source water.

In 2018, researchers at the University of Colorado Boulder and the University of Wyoming invented a radiative cooling metamaterial known as "RadiCold", which has been in development since 2017. This metamaterial helps cool water and increase the efficiency of power generation, where it would cool objects below by reflecting the sun's rays while allowing the surface to discharge its heat as infrared thermal radiation.

Contenido

Pocas aplicaciones de refrigeración se acercan a los grandes volúmenes de agua necesarios para condensar el vapor a baja presión de las centrales eléctricas.[20]​ Muchas instalaciones, sobre todo centrales eléctricas, utilizan millones de litros de agua al día para la refrigeración.[21]​ La refrigeración por agua a esta escala puede alterar los entornos acuáticos naturales y crear otros nuevos. La contaminación térmica de ríos, estuarios y aguas costeras es un factor a tener en cuenta a la hora de ubicar este tipo de centrales. El agua devuelta a los entornos acuáticos a temperaturas superiores a las del agua receptora ambiente modifica el hábitat acuático al aumentar las tasas de reacción bioquímica y disminuir la capacidad de saturación de oxígeno del hábitat. Los aumentos de temperatura favorecen inicialmente un cambio de población de las especies que requieren la alta concentración de oxígeno del agua fría a las que disfrutan de las ventajas de las mayores tasas metabólicas del agua caliente.[9]​.

Los sistemas de refrigeración de un solo paso (OTC) pueden utilizarse en ríos muy grandes o en emplazamientos costeros y estuarinos. Estas centrales vierten el calor residual en el agua del río o de la costa. Por lo tanto, estos sistemas dependen de un buen suministro de agua de río o de mar para sus necesidades de refrigeración. Estas instalaciones se construyen con estructuras de toma diseñadas para bombear grandes volúmenes de agua a un caudal elevado. Estas estructuras suelen arrastrar también un gran número de peces y otros organismos acuáticos, que mueren o resultan heridos en las rejillas de admisión.[22]​ Los grandes caudales pueden inmovilizar a los organismos de natación lenta, incluidos los peces y las gambas "Gamba (crustáceo)"), en las rejillas que protegen de la obstrucción los tubos de pequeño diámetro de los intercambiadores de calor. Las altas temperaturas o la turbulencia y el cizallamiento de la bomba pueden matar o inutilizar a los organismos más pequeños que pasan por las rejillas arrastrados por el agua de refrigeración.[23]​ Más de 1.200 centrales eléctricas y fabricantes utilizan sistemas OTC en EE. UU.[24]​ y las estructuras de admisión matan miles de millones de peces y otros organismos cada año.[25]​ Los depredadores acuáticos más ágiles consumen los organismos atrapados en las rejillas; y los depredadores y carroñeros de aguas cálidas colonizan la descarga de agua de refrigeración para alimentarse de los organismos arrastrados.

La Ley de Agua Limpia de EE. UU. requiere que la Agencia de Protección Ambiental (EPA) emita regulaciones sobre las estructuras de toma de agua de refrigeración industrial.[26]​ La EPA emitió regulaciones finales para nuevas instalaciones en 2001 (modificadas en 2003),[27]​ y para instalaciones existentes en 2014.

cooling towers

As an alternative to OTC, industrial cooling towers can use recirculated river water, coastal water (seawater), or well water. Large mechanical induced or forced draft cooling towers in industrial plants continuously circulate cooling water through heat exchangers and other equipment in which the water absorbs heat. That heat is then expelled to the atmosphere through the partial evaporation of water in cooling towers, where rising air comes into contact with the downward flow of circulating water. The loss of evaporated water in the air that is expelled to the atmosphere is replaced by fresh "makeup" river water or fresh cooling water; but the volumes of water lost during evaporative cooling can decrease the natural habitat of aquatic organisms. Since the evaporation of pure water is replaced by makeup water containing carbonates and other dissolved salts, a portion of the circulating water is also continuously discarded as "bleed" water to prevent excessive salt buildup in the circulating water; and these blowdown residues can change the quality of the receiving water.[28]​.

La camisa de agua que rodea un motor es muy eficaz para amortiguar los ruidos mecánicos, lo que hace que el motor sea más silencioso.

Open method

An open water cooling system uses evaporative cooling, reducing the temperature of the remaining (non-evaporated) water. This method was common in early internal combustion engines, until scale buildup of dissolved salts and minerals in water was observed. Modern open cooling systems continuously discard a fraction of the recirculation water as blowdown to remove dissolved solids at concentrations low enough to prevent scale formation. Some open systems use cheap tap water, but this requires higher purge rates than deionized or distilled water. Purified water systems still require purging to remove buildup of chemical treatment byproducts and prevent corrosion and biofouling.[7]​.

Pressurization

Water cooling also has a boiling point temperature of around 100 degrees C at atmospheric pressure. Engines operating at higher temperatures may require a pressurized recycle circuit to prevent overheating.[29] Modern automotive cooling systems typically operate at 15 psi (103 kPa) to raise the boiling point of the recycle water coolant and reduce evaporation losses.[30]

Antifreeze

Using water cooling carries the risk of freeze damage. Automotive and many other engine cooling applications require the use of a mixture of water and antifreeze to reduce the freezing point to an unlikely temperature. Antifreeze also inhibits the corrosion of dissimilar metals and can increase the boiling point, allowing a wider range of water cooling temperatures.[31] Its characteristic odor also alerts users to leaks and problems in the cooling system that would go unnoticed in a water-only cooling system. The heated coolant mixture can also be used to heat the air inside the car using the heater core.

Other additives

Other less common chemical additives are products to reduce surface tension. These additives are intended to increase the efficiency of automobile cooling systems. Such products are used to improve cooling of low-performance or undersized cooling systems or in racing where the weight of a larger cooling system could be a disadvantage.

Liquid cooling maintenance

Liquid cooling techniques are increasingly used for thermal management of electronic components. This type of cooling is a solution to ensure optimization of energy efficiency while minimizing noise and space requirements. Especially useful in supercomputers or Data Centers, since rack maintenance is quick and simple. Once the rack is disassembled, the advanced technology quick couplings eliminate spills for greater operator safety and protect the integrity of the fluids (no impurities in the circuits). In electronic technology it is important to analyze the connection systems to guarantee:

Water cooling typically adds complexity and cost compared to air-cooled design, as it requires a pump, tubes or pipes to transport the water and a radiator, often with fans, to exhaust heat to the atmosphere. Depending on the application, water cooling can create an additional element of risk, as leaks from the coolant recycle circuit can corrode or short-circuit sensitive electronic components.

The main advantage of water cooling for cooling CPU cores in computing equipment is that it transports heat from the source to a secondary cooling surface, allowing large, optimally designed radiators to be used instead of small, relatively inefficient fins mounted directly above the heat source. Cooling hot computer components with various fluids has been used at least since Cray-2 in 1982, with Fluorinert. Throughout the 1990s, water cooling for home PCs slowly gained recognition among enthusiasts, but became noticeably more prevalent following the introduction of the first gigahertz clocked processors in the early 2000s. As of 2018, there are dozens of manufacturers of water cooling components and kits, and many computer manufacturers include pre-installed water cooling solutions for their high-performance systems.

Water cooling can be used to cool many computer components, but is typically used for the CPU and GPU. Water cooling generally uses a water block, a water pump, and a water-to-air heat exchanger. By transferring heat from the device to a separate heat exchanger, which can be larger in size and use larger, lower speed fans, water cooling can allow for quieter operation, improved processor speed (overclocking), or a balance of both. Less commonly, Northbridges, Southbridges, hard drives, memory, voltage regulator modules (VRMs), and even power supplies can be water cooled.[32]​.

The size of the internal radiator can vary: from 40 mm with dual fans (80 mm) to 140 with quad fans (560 mm) and the thickness from 30 mm to 80 mm. Radiator fans can be mounted on one or both sides. External radiators can be much larger than their internal counterparts, as they do not need to fit in the confines of a computer case. Higher-end cases may have two ports with rubber grommets on the back for inlet and outlet hoses, allowing external radiators to be placed away from the PC.

Specialized overclockers have occasionally used vapor compression cooling or thermoelectric coolers instead of the more common standard heat exchangers. Water cooling systems, in which water is cooled directly by the evaporator coil of a phase change system, are capable of cooling the circulating coolant below the ambient air temperature (impossible with a standard heat exchanger) and, as a result, typically provide superior cooling of the computer's heat-generating components. The disadvantage of phase change or thermoelectric cooling is that it consumes much more electricity and, due to the low temperature, antifreeze must be added. Additionally, to prevent damage caused by condensation of water vapor in the air on cooled surfaces, insulation must be used, typically in the form of heat insulation around water pipes and neoprene pads around components to be cooled. A home dehumidifier or air conditioner are common places to borrow the necessary phase transition systems.[33]​.

Water is an ideal cooling medium for ships, as they are constantly surrounded by water that is generally kept at a low temperature throughout the year. Systems that operate with seawater should be made of cupro-nickel, bronze, titanium or similar corrosion-resistant materials. Water containing sediment may require velocity restrictions through pipes to prevent high-velocity erosion or blockage by low-velocity sedimentation.[34]​.

Plant transpiration and animal transpiration use evaporative cooling to prevent high temperatures from causing unsustainable metabolic rates.

Machine guns used in fixed defensive positions sometimes use water cooling to extend barrel life during periods of rapid fire, but the weight of the water and pump system greatly reduces the portability of water-cooled firearms. Water-cooled machine guns were widely used by both sides during World War I, but towards the end of the war lighter weapons began to appear on the battlefield that rivaled the firepower, effectiveness and reliability of water-cooled models, so these weapons have played a much smaller role in later conflicts.

A Swedish hospital uses meltwater to cool its data centers and medical equipment and maintain a comfortable room temperature.[35]​.

Some nuclear reactors use heavy water for cooling. Heavy water is used in nuclear reactors because it is a weaker neutron absorber. This allows the use of less enriched fuel. For the main cooling system, normal water is preferably used through the use of a heat exchanger, since heavy water is much more expensive. Reactors that use other materials for moderation (graphite) can also use normal water for cooling.

High-quality industrial water (produced by reverse osmosis or distillation) and drinking water are sometimes used in industrial plants that require high-purity cooling water. The production of these high-purity waters generates residual by-product brines that contain the concentrated impurities of the source water.

In 2018, researchers at the University of Colorado Boulder and the University of Wyoming invented a radiative cooling metamaterial known as "RadiCold", which has been in development since 2017. This metamaterial helps cool water and increase the efficiency of power generation, where it would cool objects below by reflecting the sun's rays while allowing the surface to discharge its heat as infrared thermal radiation.