60-502: The Maybach HL230 was a water-cooled 60° 23 litre V12 petrol engine designed by Maybach . It was used during World War II in medium and heavy German tanks – the Panther , Jagdpanther , Tiger II , Jagdtiger (HL230 P30), and later versions of the Tiger I and Sturmtiger (HL230 P45). The engine was an upgraded version of the slightly smaller HL210 engine which was used to equip
120-455: A T-Line . More recently a growing number of companies are manufacturing water-cooling components compact enough to fit inside a computer case. This, and the trend to CPUs of higher power dissipation, has greatly increased the popularity of water cooling. Dedicated overclockers have occasionally used vapor-compression refrigeration or thermoelectric coolers in place of more common standard heat exchangers. Water cooling systems in which water
180-482: A boiling point temperature of around 100 degrees C at atmospheric pressure. Engines operating at higher temperatures may require a pressurized recycle loop to prevent overheating. Modern automotive cooling systems often operate at 15 psi (103 kPa) to raise the boiling-point of the recycling water coolant and reduce evaporative losses. The use of water cooling carries the risk of damage from freezing. Automotive and many other engine cooling applications require
240-498: A fluid being cooled, or contact cooling water may directly impinge on items like saw blades where phase difference allows easy separation . Environmental regulations emphasize the reduced concentrations of waste products in non-contact cooling water. Water accelerates the corrosion of metal parts and is a favorable medium for biological growth. Dissolved minerals in natural water supplies are concentrated by evaporation to leave deposits called scale. Cooling water often requires
300-433: A gas . The enthalpy of vaporization is a function of the pressure and temperature at which the transformation ( vaporization or evaporation ) takes place. The enthalpy of vaporization is often quoted for the normal boiling temperature of the substance. Although tabulated values are usually corrected to 298 K , that correction is often smaller than the uncertainty in the measured value. The heat of vaporization
360-493: A recirculating system or used in a single-pass once-through cooling (OTC) system. Water's high enthalpy of vaporization allows the option of efficient evaporative cooling to remove waste heat in cooling towers or cooling ponds . Recirculating systems are open if they rely upon evaporative cooling or closed if heat removal is accomplished in heat exchangers , thus with negligible evaporative loss. A heat exchanger or condenser may separate non-contact cooling water from
420-456: A closed system. Biofouling occurs because water is a favorable environment for many life forms. Flow characteristics of recirculating cooling water systems encourage colonization by sessile organisms using the circulating supply of food, oxygen and nutrients. Temperatures may become high enough to support thermophilic populations of organisms such as types of fungi . Biofouling of heat exchange surfaces can reduce heat transfer rates of
480-725: A comfortable ambient temperature. Some nuclear reactors use heavy water as coolant. Heavy water is employed in nuclear reactors because it is a weaker neutron absorber . This allows for the use of less-enriched fuel. 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 . High-grade industrial water (produced by reverse osmosis or distillation ) and potable water are sometimes used in industrial plants requiring high-purity cooling water. Production of these high-purity waters creates waste byproduct brines containing
540-546: A condensed phase ( Δ v S {\displaystyle \Delta _{\text{v}}S} is always positive), and from the Gibbs free energy change falls with increasing temperature: gases are favored at higher temperatures, as is observed in practice. Estimation of the enthalpy of vaporization of electrolyte solutions can be simply carried out using equations based on the chemical thermodynamic models, such as Pitzer model or TCPC model. The vaporization of metals
600-442: A cooling water system is reported as the pH level. Low pH values increase the rate of corrosion; high pH values encourage scale formation. Amphoterism is uncommon among metals used in water cooling systems, but aluminum corrosion rates increase with pH values above 9. Galvanic corrosion may be severe in water systems with copper and aluminum components. Acid can be added to cooling water systems to prevent scale formation if
660-476: A film of gamma iron oxide and zinc phosphate can inhibit corrosion by passivating anodic and cathodic reaction points. These increase salinity and total dissolved solids, and phosphorus compounds may provide the limiting essential nutrient for algal growth contributing to biofouling of the cooling system or to eutrophication of natural aquatic environments receiving blowdown or OTC water. Chromates reduce biofouling in addition to effective corrosion inhibition in
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#1732859518859720-426: A fraction of recirculating water as blowdown to remove dissolved solids at concentrations low enough to prevent scale formation. Some open systems use inexpensive tap water , but this requires higher blowdown rates than deionized or distilled water . Purified water systems still require blowdown to remove the accumulation of byproducts of chemical treatment to prevent corrosion and biofouling. Water for cooling has
780-429: A high rate of flow. These structures tend to also pull in large numbers of fish and other aquatic organisms, which are killed or injured on the intake screens . Large flow rates may trap slow-swimming organisms including fish and shrimp on screens protecting the small bore tubes of the heat exchangers from blockage. High temperatures or pump turbulence and shear may kill or disable smaller organisms that pass through
840-615: A low temperature throughout the year. Systems operating with seawater need to be manufactured from cupronickel , bronze , titanium or similarly corrosion-resistant materials. Water containing sediment may require velocity restrictions through piping to avoid erosion at high velocity or blockage by settling at low velocity. Plant transpiration and animal perspiration 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 through periods of rapid fire, but
900-478: A measured volume of filtered water is evaporated . Salinity indicates water density or conductivity changes caused by dissolved materials. Probability of scale formation increases with increasing total dissolved solids. Solids commonly associated with scale formation are calcium and magnesium both as carbonate and sulfate . Corrosion rates initially increase with salinity in response to increasing electrical conductivity, but then decrease after reaching
960-563: A peak as higher levels of salinity decrease dissolved oxygen levels. Some groundwater contains very little oxygen when pumped from wells, but most natural water supplies include dissolved oxygen. Increasing oxygen concentrations accelerate corrosion. Dissolved oxygen approaches saturation levels in cooling towers. It is beneficial in blowdown or OTC water being returned to natural aquatic environments. Water ionizes into hydronium (H 3 O ) cations and hydroxide (OH ) anions . The concentration of ionized hydrogen (as protonated water) in
1020-488: Is 1850 Nm (1364.5 ft lbs) at 2,100 rpm. Typical output was 600 PS (592 hp, 441 kW) at 2,500 rpm. The crankcase and block of the HL230 were made of grey cast iron and the cylinder heads from cast iron . The engine weighed 1200 kg and its dimensions were 1,000 mm × 1,190 mm × 1,310 mm (3 ft 3 in × 3 ft 11 in × 4 ft 4 in). Aspiration
1080-408: Is a consideration when siting such plants. Water returned to aquatic environments at temperatures higher than the ambient receiving water modifies aquatic habitat by increasing biochemical reaction rates and decreasing the oxygen saturation capacity of the habitat. Temperature increases initially favor a population shift from species requiring the high-oxygen concentration of cold water to those enjoying
1140-403: Is a solution to ensure the optimisation of energy efficiency while simultaneously minimising noise and space requirements. Especially useful in supercomputers or Data Centers because maintenance of the racks is quick and easy. After disassembly of the rack, advanced-technology quick-release couplings eliminate spillage for the safety of operators and protect the integrity of fluids (no impurities in
1200-417: Is cooled directly by the evaporator coil of a phase change system are able to chill the circulating coolant below the ambient air temperature (impossible with 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
1260-440: Is more than five times the energy required to heat the same quantity of water from 0 °C to 100 °C ( c p = 75.3 J/K·mol). Care must be taken, however, when using enthalpies of vaporization to measure the strength of intermolecular forces, as these forces may persist to an extent in the gas phase (as is the case with hydrogen fluoride ), and so the calculated value of the bond strength will be too low. This
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#17328595188591320-401: Is particularly true of metals, which often form covalently bonded molecules in the gas phase: in these cases, the enthalpy of atomization must be used to obtain a true value of the bond energy . An alternative description is to view the enthalpy of condensation as the heat which must be released to the surroundings to compensate for the drop in entropy when a gas condenses to a liquid. As
1380-411: Is proportional to the logarithm of its pressure. The entropies of liquids vary little with pressure, as the coefficient of thermal expansion of a liquid is small. These two definitions are equivalent: the boiling point is the temperature at which the increased entropy of the gas phase overcomes the intermolecular forces. As a given quantity of matter always has a higher entropy in the gas phase than in
1440-419: Is required and it has to be carefully controlled. Modern solid-state transmitters can be built so that even high-power transmitters do not require water cooling. Water cooling is however also sometimes used for thyristors of HVDC valves, for which the use of deionized water is required. Liquid cooling techniques are increasingly being used for the thermal management of electronic components. This type of cooling
1500-656: Is required only in that localized area. The disadvantage of such a system is higher power dissipation. To avoid damage from condensation around the Peltier junction, a proper installation requires it to be "potted" with silicone epoxy. The epoxy is applied around the edges of the device, preventing air from entering or leaving the interior. Apple's Power Mac G5 was the first mainstream desktop computer to have water cooling as standard (although only on its fastest models). Dell followed suit by shipping their XPS computers with liquid cooling , using thermoelectric cooling to help cool
1560-846: Is required. Chlorine may be added in the form of hypochlorite to decrease biofouling in cooling water systems, but is later reduced to chloride to minimize the toxicity of blowdown or OTC water returned to natural aquatic environments. Hypochlorite is increasingly destructive to wooden cooling towers as pH increases. Chlorinated phenols have been used as biocides or leached from preserved wood in cooling towers. Both hypochlorite and pentachlorophenol have reduced effectiveness at pH values greater than 8. Non-oxidizing biocides may be more difficult to detoxify prior to release of blowdown or OTC water to natural aquatic environments. Concentrations of polyphosphates or phosphonates with zinc and chromates or similar compounds have been maintained in cooling systems to keep heat exchange surfaces clean enough that
1620-405: Is temperature-dependent, though a constant heat of vaporization can be assumed for small temperature ranges and for Reduced temperature T r ≪ 1 . The heat of vaporization diminishes with increasing temperature and it vanishes completely at a certain point called the critical temperature ( T r = 1 ). Above the critical temperature, the liquid and vapor phases are indistinguishable, and
1680-841: Is used for the CPU and GPUs . Water cooling typically uses a water block , a water pump , and a water-to-air heat exchanger. By transferring device heat to a separate larger heat exchanger using larger, lower-speed fans, water cooling can allow quieter operation, improved processor speeds ( overclocking ), or a balance of both. Less commonly, Northbridges , Southbridges , hard disk drives , memory , voltage regulator modules (VRMs), and even power supplies can be water-cooled. Internal radiator size may vary: from 40 mm dual fan (80 mm) to 140 quad fan (560 mm) and thickness from 30 mm to 80 mm. Radiator fans may 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
1740-600: The Environmental Protection Agency (EPA) to issue regulations on industrial cooling water intake structures. EPA issued final regulations for new facilities in 2001 (amended 2003), and for existing facilities in 2014. As an alternative to OTC, industrial cooling towers may use recirculated river water, coastal water ( seawater ), or well water. Large mechanical induced-draft or forced-draft cooling towers in industrial plants continuously circulate cooling water through heat exchangers and other equipment where
1800-456: The heater core . Also, the water jacket around an engine is very effective at deadening mechanical noises, making the engine quieter. An open water cooling system makes use of evaporative cooling , lowering the temperature of the remaining (unevaporated) water. This method was common in early internal combustion engines until scale buildup was observed from dissolved salts and minerals in the water. Modern open cooling systems continuously waste
1860-581: The "tee" connector, and ultimately removed from the system by bleeding. The capped line may be capped with a fill-port fitting to allow the release of trapped gas and the addition of liquid. Water coolers for desktop computers were, until the end of the 1990s, homemade. They were made from car radiators (or more commonly, a car's heater core ), aquarium pumps and home-made water blocks, laboratory-grade PVC and silicone tubing and various reservoirs (homemade using plastic bottles, or constructed using cylindrical acrylic or sheets of acrylic, usually clear) and or
Maybach HL230 - Misplaced Pages Continue
1920-618: The Richard I underground factory at Leitmeritz concentration camp . Water-cooled Water cooling is a method of heat removal from components and industrial equipment. Evaporative cooling using water is often more efficient than air cooling . Water is inexpensive and non-toxic; however, it can contain impurities and cause corrosion. Water cooling is commonly used for cooling automobile internal combustion engines and power stations . Water coolers utilising convective heat transfer are used inside high-end personal computers to lower
1980-431: The addition of chemicals to minimize corrosion and insulating deposits of scale and biofouling. Water contains varying amounts of impurities from contact with the atmosphere, soil, and containers. Being both an electrical conductor and a solvent for metal ions and oxygen, water can accelerate corrosion of machinery being cooled. Corrosion reactions proceed more rapidly as temperature increases. Preservation of machinery in
2040-446: The advantages of increased metabolic rates in warm water. Once-through cooling (OTC) systems may be used on very large rivers or at coastal and estuarine sites. These power stations put the waste heat into the river or coastal water. These OTC systems thus rely upon an ample supply of river water or seawater for their cooling needs. Such facilities are built with intake structures designed for bringing in large volumes of water at
2100-414: The ambient temperature while obviating 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
2160-412: The circuits). These couplings are also capable of being locked (Panel mounted?) to allow blind connection in difficult-to-access areas. It is important in electronics technology to analyse the connection systems to ensure: Water cooling often adds complexity and cost in comparison to air cooling design by requiring a pump, tubing or piping to transport the water, and a radiator, often with fans, to reject
2220-457: The concentrated impurities from the source water. In 2018, researchers from the University of Colorado Boulder and University of Wyoming invented a radiative cooling metamaterial known as "RadiCold", which has been developed since 2017. This metamaterial aids in cooling of water and increasing the efficiency of power generation, in which it would cool the underneath objects, by reflecting away
2280-483: The confines of a computer case. High-end cases may have two rubber grommeted ports in the back for the inlet and outlet hoses, which allow external radiators to be placed far away from the PC. A T-Line is used to remove trapped air bubbles from the circulating water. It is made with a t-connector and a capped-off length of tubing. The tube n acts as a mini-reservoir and allows air bubbles to travel into it as they are caught into
2340-654: The cooling system, and biofouling of cooling towers can alter flow distribution to reduce evaporative cooling rates. Biofouling may also create differential oxygen concentrations increasing corrosion rates. OTC and open recirculating systems are more susceptible to biofouling. Biofouling may be inhibited by temporary habitat modifications. Temperature differences may discourage the establishment of thermophilic populations in intermittently operated facilities, and intentional short-term temperature spikes may periodically kill less tolerant populations. Biocides have been commonly used to control biofouling where sustained facility operation
2400-421: The cooling water system, but residual toxicity in blowdown or OTC water has encouraged lower chromate concentrations and the use of less-flexible corrosion inhibitors. Blowdown may also contain chromium leached from cooling towers constructed of wood preserved with chromated copper arsenate . Total dissolved solids or TDS (sometimes called filterable residue) is reported as the mass of residue remaining when
2460-408: 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. Since approximately 1930 it is common to use water cooling for tubes of powerful transmitters. As these devices use high operation voltages (around 10 kV), the use of deionized water
Maybach HL230 - Misplaced Pages Continue
2520-401: The evaporated pure water is replaced by make-up water containing carbonates and other dissolved salts, a portion of the circulating water is continuously discarded as "blowdown" water to minimize the excessive build-up of salts in the circulating water; these blowdown wastes may change the receiving water quality. The heated coolant mixture can be used to warm the air inside the car by means of
2580-652: The first 250 Tiger I tanks built, and which had an aluminium crankcase and block . The earlier HL210 engine had a displacement of 21.353 L (1,303.0 cu in) or 1,779 cm³ per cylinder; bore 125 mm (4.9 in), stroke 145 mm (5.7 in). With the HL230 , engine bore was increased from 125 mm to 130 mm. It had a displacement of 23.095 L (1,409.3 cu in) or 1,925 cm³ per cylinder; bore 130 mm (5.1 in), stroke 145 mm (5.7 in). The maximum output of 700 PS (690 hp, 515 kW) at 3,000 rpm . Maximum torque
2640-680: The heat source. Cooling hot computer components with various fluids has been in use since at least the Cray-2 in 1982, which used Fluorinert . Through the 1990s, water cooling for home PCs slowly gained recognition among enthusiasts, but it became noticeably more prevalent after 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 preinstalled water cooling solutions for their high-performance systems. Water cooling can be used for many computer components, but usually it
2700-508: The heat to the atmosphere. Depending on the application, water cooling may create an additional element of risk where leakage from the water coolant recycle loop can corrode or short-circuit sensitive electronic components. The primary advantage of water cooling for cooling CPU cores in computing equipment is transporting heat away from the source to a secondary cooling surface to allow for large, more optimally designed radiators rather than small, relatively inefficient fins mounted directly on
2760-481: The internal energy can be viewed as the energy required to overcome the intermolecular interactions in the liquid (or solid, in the case of sublimation ). Hence helium has a particularly low enthalpy of vaporization, 0.0845 kJ/mol, as the van der Waals forces between helium atoms are particularly weak. On the other hand, the molecules in liquid water are held together by relatively strong hydrogen bonds , and its enthalpy of vaporization, 40.65 kJ/mol,
2820-416: The liquid and gas are in equilibrium at the boiling point ( T b ), Δ v G = 0, which leads to: As neither entropy nor enthalpy vary greatly with temperature, it is normal to use the tabulated standard values without any correction for the difference in temperature from 298 K. A correction must be made if the pressure is different from 100 kPa , as the entropy of an ideal gas
2880-485: The liquid. Currently, Dell's only computers to offer liquid cooling are their Alienware desktops. Asus are the first and only mainstream brand to have put water-cooled laptops into mass production. Those laptops have a built-in air/water hybrid cooling system and can be docked to an external liquid cooling radiator for additional cooling and electrical power. Water is an ideal cooling medium for vessels as they are constantly surrounded by water that generally remains at
2940-476: 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 chilled surfaces. Common places from which to obtain the required phase transition systems are a household dehumidifier or air conditioner . An alternative cooling scheme, which also enables components to be cooled below
3000-417: The opposite sign: enthalpy changes of vaporization are always positive (heat is absorbed by the substance), whereas enthalpy changes of condensation are always negative (heat is released by the substance). The enthalpy of vaporization can be written as It is equal to the increased internal energy of the vapor phase compared with the liquid phase, plus the work done against ambient pressure. The increase in
3060-462: The pH decrease will offset increased salinity and dissolved solids. Few other cooling applications approach the large volumes of water required to condense low-pressure steam at power stations . Many facilities, particularly electric power plants, use millions of gallons of water per day for cooling. Water cooling on this scale may alter natural water environments and create new environments. Thermal pollution of rivers, estuaries and coastal waters
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#17328595188593120-654: The presence of hot water has been improved by addition of corrosion inhibitors including zinc , chromates and phosphates . The first two have toxicity concerns; and the last has been associated with eutrophication . Residual concentrations of biocides and corrosion inhibitors are of potential concern for OTC and blowdown from open recirculating cooling water systems. With the exception of machines with short design life, closed recirculating systems require periodic cooling-water treatment or replacement raising similar concern about ultimate disposal of cooling water containing chemicals used with environmental safety assumptions of
3180-435: The screens entrained with the cooling water. More than 1,200 power plants and manufacturing facilities in the U.S. use OTC systems; the intake structures kill billions of fish and other organisms each year. More-agile aquatic predators consume organisms impinged on the screens; and warm water predators and scavengers colonize the cooling water discharge to feed on entrained organisms. The U.S. Clean Water Act required
3240-402: The substance is called a supercritical fluid . Values are usually quoted in J / mol , or kJ/mol (molar enthalpy of vaporization), although kJ/kg, or J/g (specific heat of vaporization), and older units like kcal /mol, cal/g and Btu /lb are sometimes still used among others. The enthalpy of condensation (or heat of condensation ) is by definition equal to the enthalpy of vaporization with
3300-431: The sun's rays while at the same time allowing the surface to discharge its heat as infrared thermal radiation. Enthalpy of vaporization In thermodynamics , the enthalpy of vaporization (symbol ∆ H vap ), also known as the ( latent ) heat of vaporization or heat of evaporation , is the amount of energy ( enthalpy ) that must be added to a liquid substance to transform a quantity of that substance into
3360-650: The temperature of CPUs and other components. Other uses include the cooling of lubricant oil in pumps ; for cooling purposes in heat exchangers ; for cooling buildings in HVAC and in chillers . Water is inexpensive, non-toxic , and available over most of the earth's surface. Liquid cooling offers higher thermal conductivity than air cooling. Water has unusually high specific heat capacity among commonly available liquids at room temperature and atmospheric pressure allowing efficient heat transfer over distance with low rates of mass transfer. Cooling water may be recycled through
3420-518: 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. Other less common chemical additives are products to reduce surface tension. These additives are meant to increase
3480-433: The water absorbs heat. That heat is then rejected to the atmosphere by the evaporation of some of the water in cooling towers where upflowing air contacts the downflowing 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, but the amount of water lost during evaporative cooling may affect the natural habitat for aquatic organisms. Because
3540-609: The weight of the water and pumping system significantly reduces the portability of water-cooled firearms. Water-cooled machine guns were extensively used by both sides during World War I ; however, by the end of the war lighter weapons that rivaled the firepower, effectiveness and reliability of water-cooled models began to appear on the battlefield. Thus water-cooled weapons have played a far lesser role in subsequent conflicts. A hospital in Sweden relies on snow-cooling from melt-water to cool its data centers, medical equipment, and maintain
3600-749: Was provided by four twin-choke Solex type 52JFF carburettors . Ignition was by two magnetos. The compression ratio was 6.8:1. As was typical practice for Maybach, the engine used a tunnel crankshaft . Late in the war the HL234 upgrade with fuel injection was recommended by the Entwicklungskommission Panzer for use in the underpowered Tiger II tank. The power output was expected to increase to between 800 and 900 PS (hp), and with supercharging to 1100 to 1200 hp. Approximately 9,000 HL230s were produced in total by Maybach, Auto Union and Daimler-Benz . Beginning on 3 November 1944, they were produced at
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