Condenser (heat transfer): Difference between revisions
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No part of that "equation" is practically possible because condensers condense gases into liquids and there are no "constants" involved. Tag: section blanking |
Brief synopsis of condenser differences and similarities |
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[[File:Lednička Zanussi ZRA 319 SW, celkový pohled na zadní část.JPG|thumb|The condenser coil of a refrigerator]]In systems involving [[heat transfer]], a '''condenser''' is a heat exchanger which allows heat transfer from a high-temperature gas passing through it to a cooler liquid or gas outside of it. |
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[[File:Lednička Zanussi ZRA 319 SW, celkový pohled na zadní část.JPG|thumb|The condenser coil of a refrigerator]]In systems involving [[heat transfer]], a '''condenser''' is a device or unit used to [[Condensation|condense]] a substance from its [[gas]]eous to its [[liquid]] state, by cooling it. In so doing, the [[latent heat]] is given up by the substance and transferred to the surrounding environment. Condensers can be made according to numerous designs, and come in many sizes ranging from rather small (hand-held) to very large (industrial-scale units used in plant processes). For example, a [[refrigerator]] uses a condenser to get rid of [[heat]] extracted from the interior of the unit to the outside air. Condensers are used in [[air conditioning]], industrial [[chemical process]]es such as [[distillation]], steam [[power plant]]s and other heat-exchange systems. Use of cooling water or surrounding air as the coolant is common in many condensers.<ref name=chemengenc>{{citation|title=Encyclopedia of CHemical Engineering Equipment| contribution = Condensers|publisher= [[University of Michigan]]|accessdate=May 13, 2012|url=http://encyclopedia.che.engin.umich.edu/Pages/HeatTransfer/Condensers/Condensers.html |
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|last1=Hindelang|first1=Man jjhat |
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When used to condense water vapor back into liquid water, it functions primarily as an expansion chamber with water naturally condensing as its vapor pressure and pressure-elevated boiling point drop. High-pressure steam is the result of water boiling at far over the 212 degrees F/100 degrees C at which pure water boils at sea level at 60 degrees F and 29.92 in.hg. |
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|last2=Palazzolo|first2=Joseph |
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|last3=Robertson|first3=Matthew}}</ref> |
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When the condenser is part of a refrigeration system with a compressor, which actually pumps liquid refrigerant with the resulting pressure increase resulting from flow restriction rather that "compression" of the constant-volume, closed-loop refrigerant supply, and expansion orifice and evaporator, the evaporator removes heat from the air in the refrigerated space as it flows to and through the expansion orifice as a high-pressure liquid. As it flows through the orifice and into the evaporator its pressure and temperature drop dramatically and it becomes a low-pressure, low-temperature liquid. |
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== Examples of condensers == |
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*A [[surface condenser]] is one in which condensing medium and vapors are physically separated and used when direct contact is not desired. It is a [[shell and tube heat exchanger]] installed at the outlet of every [[steam turbine]] in [[thermal power station]]s. Commonly, the [[cooling water]] flows through the tube side and the steam enters the shell side where the condensation occurs on the outside of the heat transfer tubes. The condensate drips down and collects at the bottom, often in a built-in pan called a ''hotwell''. The shell side often operates at a [[vacuum]] or partial vacuum, produced by the difference in specific volume between the steam and condensate. Conversely, the vapor can be fed through the tubes with the coolant water or air flowing around the outside. |
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* In [[chemistry]], a condenser is the apparatus which cools hot [[vapor]]s, causing them to condense into a [[liquid]]. See "[[Condenser (laboratory)]]" for [[laboratory]]-scale condensers, as opposed to industrial-scale condensers. Examples include the [[Liebig condenser]], [[Graham condenser]], and [[Allihn condenser]]. This is not to be confused with a [[condensation reaction]] which links two fragments into a single molecule by an addition [[Chemical reaction|reaction]] and an elimination reaction. |
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As it passes through the heat-sink evaporator typically made of aluminum for its light weight, low density and corrosion resistance in contact with dust and water vapor condensing on its surface, the refrigerant is heated as internal air to be refrigerated by having heat removed from it flows over the evaporator. As heat is removed from the air by the refrigerated liquid absorbing it, the liquid becomes hotter and partially or completely boils and is drawn from the evaporator as a high-temperature, low-pressure gas by the pumping compressor located at the condenser outlet. Heat is released at the condenser and the cycle continues until the thermostatic switch which prevents evaporator icing or the internal temperature desired and set by the temperature control thermostat is reached. |
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:In laboratory [[distillation]], [[reflux]], and [[rotary evaporator]]s, several types of condensers are commonly used. The Liebig condenser is simply a straight tube within a cooling water jacket, and is the simplest (and relatively least expensive) form of condenser. The Graham condenser is a spiral tube within a water jacket, and the Allihn condenser has a series of large and small constrictions on the inside tube, each increasing the surface area upon which the vapor constituents may condense. Being more complex shapes to manufacture, these latter types are also more expensive to purchase. These three types of condensers are [[laboratory glassware]] items since they are typically made of glass. Commercially available condensers usually are fitted with ground glass joints and come in standard lengths of 100, 200, and 400 mm. Air-cooled condensers are unjacketed, while water-cooled condensers contain a jacket for the water. |
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In both examples temperature and pressure and state changes take place but in only the latter does the condensor perform all the work of condensing the gas in a continuous cycle. In steam systems and condensers, a feedwater pump injects the condensed water into the boiler as required to maintain the correct boiler water level and the condenser also serves as a de-aeration, makeup water and treatment reservoir. Steam condensers are typically cooled only to the minimum necessary for those to occur as over-cooling would waste fuel and heat energy. In refrigeration system the cooler and more dense the refrigerant leaving the condenser is, the better the system functions and the more efficient it is. |
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*Larger condensers are also used in industrial-scale distillation processes to cool distilled [[vapor]] into liquid distillate. Commonly, the coolant flows through the tube side and distilled vapor through the shell side with distillate collecting at or flowing out the bottom. |
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[[File:Condenser unit for central air conditioning.JPG|thumb|'''Condenser unit''' for central air conditioning for a typical house]] |
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*A '''condenser unit''' used in [[central air conditioning]] systems typically has a heat exchanger section to cool down and condense incoming [[refrigerant]] vapor into liquid, a [[gas compressor|compressor]] to raise the pressure of the refrigerant and move it along, and a fan for blowing outside air through the heat exchanger section to cool the refrigerant inside. A typical configuration of such a condenser unit is as follows: The heat exchanger section wraps around the sides of the unit with the compressor inside. In this heat exchanger section, the refrigerant goes through multiple tube passes, which are surrounded by heat transfer fins through which cooling air can circulate from outside to inside the unit. There is a motorized [[Fan (mechanical)|fan]] inside the condenser unit near the top, which is covered by some grating to keep any objects from accidentally falling inside on the fan. The fan is used to pull outside cooling air in through the heat exchanger section at the sides and blow it out the top through the grating. These condenser units are located on the outside of the building they are trying to cool, with tubing between the unit and building, one for vapor refrigerant entering and another for liquid refrigerant leaving the unit. Of course, an [[electric power]] supply is needed for the compressor and fan inside the unit. |
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*In a '''direct-contact condenser''', hot vapor and cool liquid are introduced into a vessel and allowed to mix directly, rather than being separated by a barrier such as the wall of a heat exchanger tube. The vapor gives up its [[latent heat]] and condenses to a liquid, while the liquid absorbs this heat and undergoes a temperature rise. The entering vapor and liquid typically contain a single condensable substance, such as a water spray being used to cool air and adjust its humidity. |
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'''Other Types of Condensers''' |
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In the world of [[Heating, Ventilation, and Air Conditioning]] (HVAC), condensers happen to be a topic of great importance. Instead of confusing information, the goal is to provide some basic information on the [http://www.tinita.in/titanium-condenser-manufacturers-exporters.html different types of condensers] and their applications. |
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There are three other condensers used in HVAC systems: |
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*'''Water-cooled''' |
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*'''Air-cooled''' |
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*'''Evaporative''' |
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'''Applications:''' |
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*'''Air cooled''' – If the condenser is located on the outside of the unit, the air cooled condenser can provide the easiest arrangement. These types of condensers eject heat to the outdoors and are simple to install. |
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Most common uses for this condenser are domestic refrigerators, upright freezers and in residential packaged air conditioning units. A great feature of the air cooled condenser is they are very easy to clean. Since dirt can cause serious issues with the condensers performance, it is highly recommended that these be kept clear of dirt. |
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*'''Water cooled''' – Although a little more pricey to install, these condensers are the more efficient type. Commonly used for swimming pools and condensers piped for city water flow, these condensers require regular service and maintenance. |
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They also require a cooling tower to conserve water. To prevent corrosion and the forming of algae, water cooled condensers require a constant supply of makeup water along with water treatment. |
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Depending on the application you can choose from tube in tube, shell and coil or shell and tube condensers. All are essentially made to produce the same outcome, but each in a different way. |
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*'''Evaporative''' – While these remain the least popular choice, they are used when either water supply is inadequate to operate water cooled condenser or condensation temperature is lower that can achieved by air cooled condenser. Evaporative condensers can be used inside or outside of a building and under typical conditions, operate at a low condensing temperature. |
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Typically these are used in large commercial air-conditioning units. Although effective, they are not necessarily the most efficient. |
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==See also== |
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* [[Condenser (laboratory)]] |
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* [[Air well (condenser)]] |
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== References == |
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{{Commons category|Condensers}} |
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{{reflist}} |
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{{Steam engine configurations|state=collapsed}} |
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{{Authority control}} |
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[[Category:Heating, ventilating, and air conditioning]] |
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[[Category:Laboratory glassware]] |
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[[Category:Heat transfer]] |
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[[Category:Gas technologies]] |
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[[Category:Heat exchangers]] |
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[[pt:Condensador (química)]] |
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Revision as of 08:17, 17 February 2019
 | This article needs additional citations for verification. (March 2015) |
In systems involving heat transfer, a condenser is a heat exchanger which allows heat transfer from a high-temperature gas passing through it to a cooler liquid or gas outside of it.
When used to condense water vapor back into liquid water, it functions primarily as an expansion chamber with water naturally condensing as its vapor pressure and pressure-elevated boiling point drop. High-pressure steam is the result of water boiling at far over the 212 degrees F/100 degrees C at which pure water boils at sea level at 60 degrees F and 29.92 in.hg.
When the condenser is part of a refrigeration system with a compressor, which actually pumps liquid refrigerant with the resulting pressure increase resulting from flow restriction rather that "compression" of the constant-volume, closed-loop refrigerant supply, and expansion orifice and evaporator, the evaporator removes heat from the air in the refrigerated space as it flows to and through the expansion orifice as a high-pressure liquid. As it flows through the orifice and into the evaporator its pressure and temperature drop dramatically and it becomes a low-pressure, low-temperature liquid.
As it passes through the heat-sink evaporator typically made of aluminum for its light weight, low density and corrosion resistance in contact with dust and water vapor condensing on its surface, the refrigerant is heated as internal air to be refrigerated by having heat removed from it flows over the evaporator. As heat is removed from the air by the refrigerated liquid absorbing it, the liquid becomes hotter and partially or completely boils and is drawn from the evaporator as a high-temperature, low-pressure gas by the pumping compressor located at the condenser outlet. Heat is released at the condenser and the cycle continues until the thermostatic switch which prevents evaporator icing or the internal temperature desired and set by the temperature control thermostat is reached.
In both examples temperature and pressure and state changes take place but in only the latter does the condensor perform all the work of condensing the gas in a continuous cycle. In steam systems and condensers, a feedwater pump injects the condensed water into the boiler as required to maintain the correct boiler water level and the condenser also serves as a de-aeration, makeup water and treatment reservoir. Steam condensers are typically cooled only to the minimum necessary for those to occur as over-cooling would waste fuel and heat energy. In refrigeration system the cooler and more dense the refrigerant leaving the condenser is, the better the system functions and the more efficient it is.