An absorption refrigerator is a refrigerator that uses a heat source to provide the energy needed to drive the cooling process. The principle can also be used to. Download Citation on ResearchGate | On Jul 30, , Saghar Mehdi and others published Design of Compressor less Solar Powered. design and fabricate a compressor less refrigerator system flywheel. A parametric model of the refrigerator is designed using 3D modeling software CATIA.
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An absorption refrigerator is a refrigerator that uses a heat source e. The principle can also be used to air-condition buildings using the waste heat from a gas turbine or water heater.
In the early years of the twentieth century, the vapor absorption cycle using water-ammonia systems was popular and widely used, but after the development of the vapor compression cycle it lost much of its importance because of its low refrigerafor of performance about compressorlss fifth of that of the vapor compression cycle.
Absorption refrigerators are a refriigerator alternative to regular compressor refrigerators where electricity is unreliable, costly, or unavailable, where noise from the compressor is problematic, or where surplus heat is available e.
In Baltzar von Platen and Carl Munterswhile they were still students at the Royal Institute of Technology in StockholmSwedenenhanced the principle with a 3-fluid configuration.
This “Platen-Munters” design can operate without a pump. Commercial production compreessorless in by the newly formed company AB Arcticwhich was bought by Electrolux in In the s, absorption refrigeration saw a renaissance due to the substantial demand for refrigerators for caravans travel trailers.
The company marketed refrigerators for recreational vehicles RVs under the Dometic brand. RefrjgeratorElectrolux sold most of its leisure products line to the venture-capital company EQT which created Dometic as a stand-alone company. At the TED ConferenceAdam Grosser presented his research of a new, very small, “intermittent absorption” vaccine refrigeration unit for use in third world retrigerator.
In both types, when this refrigerant evaporates boilsit takes some heat away with it, providing the cooling effect. The main difference between the two systems is the way the refrigerant is changed from a gas back into a liquid so that the cycle can repeat. An absorption refrigerator changes the gas back compresosrless a liquid using a method that needs only heat, and has no moving parts other than the refrigerant itself.
In comparison, a compressor refrigerator uses a compressor, usually powered by either an electric or internal combustion motor, to increase the pressure on the gaseous refrigerant. The resulting hot, high-pressure gas is condensed to a liquid form by cooling in a heat exchanger “condenser” that is exposed to the external environment usually air in the room.
The condensed refrigerant, now at a temperature near to that of the external environment, then passes through an orifice or a throttle valve into the evaporator section. The orifice or throttle valve creates a pressure drop between the high pressure condenser section and the low pressure evaporator section. Compressroless lower pressure in the evaporator section allows the liquid refrigerant to evaporate, which absorbs heat from the refrigerator food compartment.
The now-vaporized refrigerant then goes back into the compressor to refrigeratoor the cycle. Another difference between the two types is the refrigerant used. Compressorles simple absorption refrigeration system common in large commercial plants uses a solution of lithium bromide and lithium chloride salt and water. Water under low pressure is evaporated from the coils that are being chilled. The system drives the water off the lithium bromide solution with heat. Another compressrless, uses air, water, and a salt water solution.
The intake of warm, moist air is passed through a sprayed solution of salt water. The spray lowers the humidity but does not significantly change the temperature. The refrigeratog humid, warm air is then passed through an evaporative coolerconsisting of a spray of fresh water, which cools and re-humidifies the air.
Humidity is removed from the cooled air with another spray of salt solution, providing the outlet of cool, dry air. The salt solution is regenerated by heating refrierator under low pressure, causing water to evaporate.
The water evaporated from the salt solution is re-condensed, and rerouted back to the evaporative cooler. A single-pressure absorption refrigerator takes advantage comprrssorless the fact that a liquid’s evaporation rate depends upon the partial pressure of the vapor above the liquid and goes down with lower partial pressure.
While having the same total pressure throughout the system, the refrigerator maintains a low partial pressure of the refrigerant therefore high evaporation rate in the part of the system that draws heat out of the low-temperature interior of the refrigerator, but maintains the refrigerant at high partial pressure therefore low evaporation rate in the part of the system that expels heat tefrigerator the ambient-temperature air outside the refrigerator.
The refrigerator uses three substances: The cycle is closed, with all hydrogen, water compressorles ammonia collected and endlessly reused. The system is pressurized to the pressure where the boiling point of ammonia is higher than the temperature of the condenser coil the coil comprewsorless transfers heat to the air outside the refrigerator, by being hotter than the outside air.
The cooling cycle starts with compressorlses ammonia at room temperature entering the evaporator. The volume of the evaporator is greater than the volume of the liquid, with the excess space occupied by a mixture of gaseous ammonia and hydrogen. The presence of hydrogen lowers the partial pressure of the ammonia gas, thus lowering the evaporation rate of the liquid below the temperature of the refrigerator’s interior.
Ammonia evaporates, taking a small amount of heat from the liquid and lowering the liquid’s temperature. It continues to evaporate, while the large enthalpy of vaporization heat flows from the warmer refrigerator interior to the cooler liquid ammonia and then to more ammonia gas.
The pure ammonia gas then enters the condenser. In this heat exchangerthe hot ammonia gas transfers its heat to the outside air, which is below refrigegator boiling point of the full-pressure ammonia, and therefore condenses. The condensed liquid ammonia flows down to be mixed with the hydrogen gas released from the absorption step, repeating the cycle.
From Wikipedia, the free encyclopedia. Thermodynamics The classical Carnot heat engine.
Absorption refrigerator – Wikipedia
Classical Statistical Chemical Quantum thermodynamics. Zeroth First Second Third.
Conjugate variables in italics. Carnot’s theorem Clausius theorem Fundamental relation Ideal gas law. Free energy Free entropy. History General Heat Entropy Gas laws. Entropy and time Entropy and life Brownian ratchet Maxwell’s demon Heat death paradox Loschmidt’s paradox Synergetics. Caloric theory Theory of heat.
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The classical Carnot heat engine. Laws Zeroth First Second Third. Heat engines Heat pumps Thermal efficiency. Conjugate variables refrigegator italics Property diagrams Intensive and extensive properties. Material properties Property databases Specific heat capacity. Equations Carnot’s theorem Clausius theorem Fundamental relation Ideal gas law Maxwell refrigerrator Onsager reciprocal relations Bridgman’s equations Table of thermodynamic equations.
Caloric theory Theory of refdigerator Vis viva “living force” Mechanical equivalent of heat Motive power.
Maxwell’s thermodynamic surface Entropy as energy dispersal.