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INDEPENDENT PROJECT. Project Title :. THERMO-ACOUSTIC REFRIGERATOR. Team Members : P.Vidyasree (CE12B1016) T.Vishnupriya (EE12B1037). REFRIGERATION. Refrigeration is a process in which work is done to move heat from one location to another . Uses of Refrigeration :
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INDEPENDENT PROJECT Project Title : THERMO-ACOUSTIC REFRIGERATOR Team Members : P.Vidyasree (CE12B1016) T.Vishnupriya (EE12B1037)
REFRIGERATION Refrigerationis a process in which work is done to move heat from one location to another. Uses of Refrigeration : Industrialuses Air conditioning Food storage and distribution Medical applications
CURRENT REFRIGERATION METHODS VAPOUR COMPRESSION
DISADVANTAGES VAPOUR COMPRESSION • Require CFC, HCFC, or other ozone harming refrigerants • Increase global warming effect • Loud/noisy • Typical efficiency is 40-55% of Carnot limit • Moving parts and intricate design • Prone to breakdown VAPOUR ABSORPTION • Requires large heat source • Can't use electricity directly • Require CFC, HCFC, or other ozone harming refrigerants • Increase global warming effect • Inefficient
THERMOACOUSTIC REFRIGERATOR • A thermo-acoustic refrigerator (TAR) is a refrigerator that uses sound waves in order to provide the cooling. • In a TAR, the working fluid is a helium-argon mixture, and the compressor is replaced by a loudspeaker. WORKING PRINCIPLE • Pressure variations in sound wave are accomplished by temperature change due to particle oscillations in the gas. For a single medium average temperature at that particular location does not change. When a second medium is present heat is exchanged with it and an expanded particle will take heat from it and compressed particles will reject heat to the second medium.
ADVANTAGES • The working fluid is typically helium or other inert, benign gases such as air which are environment-friendly unlike common refrigerants. • The simplicity of the design makes it robust, small, and lightweight. • It has almost no moving parts, which translates into a longer working life with fewer repairs. In turn, this makes the system less expensive. • The loudspeaker is TAR’s only moving part which is more durable than a compressor. • It has the ability to attain a higher level of the limiting Carnot efficiency than current refrigeration methods.
DISADVANTAGES • Thedownsideof the TAR is that these failed to achieve efficiencies as high as those of standard refrigerator units. • The coefficient of performance of most advanced TAR is only 1 when compared to 3-4 of modern refrigerators. • Another major problem of TAR is that it is either fully on or off. • It leaked an incredible amount of sound that causes ear pain but produces only a small temperature gradient. • These refrigerators were able to cool the air for a short amount of time before the cooled air started raising its temperature. • very much essengerators have failed to achieve efficiencies as high as those as standard refrigeration units.
IMPROVEMENTS • Insulate the sound leaks by isolating the system. • Replace the closed cap with a speaker to increase the efficiency by co-generation. • If both ends of a stack are connected to a heat exchangers thus coupling the stack to a heat source and sink, the transfer of heat would be more efficient. • Use conductive material for hot section of resonator • Widen the resonator and use a cone to reduce the losses due to rapid area change. • More practical and efficient reliable temperature sensors such as thermistors should be used. • The composition of stack material may also be changed to any conducting materials like gold,silveror copper.