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dc.contributor.authorNagavarapu, Ananda Krishnaen_US
dc.date.accessioned2013-01-17T21:00:28Z
dc.date.available2013-01-17T21:00:28Z
dc.date.issued2012-08-14en_US
dc.identifier.urihttp://hdl.handle.net/1853/45777
dc.description.abstractAbsorption space-conditioning systems are environmentally benign alternatives to vapor compression systems and have the capability of being driven by waste heat. However, a lack of practically feasible and economically viable compact heat and mass exchangers is a major limitation in the success of this technology. The viability of the absorption cycle depends upon the performance of the absorber, which experiences large heat and mass transfer resistances due to adverse temperature and concentration gradients during the phase change of the binary mixture working fluid, resulting in large overall component sizes. Understanding of the coupled heat and mass transfer during binary fluid mixture absorption at the microscales is critical for the miniaturization of these components, which will enable broad implementation of this technology. The proposed study aims to achieve this by investigating ammonia-water absorption for two distinct flow configurations: external falling films and internal convective flows. For the falling-film absorption case, ammonia-water solution flows around an array of small diameter coolant tubes while absorbing vapor. This absorber is installed in a test facility comprising all components of a single-effect absorption chiller to provide realistic operating conditions at the absorber. Local temperature, pressure, and flow measurements will be taken over a wide range of operating conditions and analyzed to develop a heat and mass transfer model for falling-film ammonia-water absorption. A microscale convective flow absorber will also be investigated. This absorber consists of an array of parallel, aligned alternating shims with integral microscale features, enclosed between cover plates. These microscale features facilitate flow of various fluid streams and the associated heat and mass transfer. The use of microchannels induces high heat and mass transfer rates without any active or passive surface enhancement. The microscale absorber for small-scale applications will be evaluated over a wide range of operating conditions on a single-effect absorption heat pump breadboard test facility. The study will conclude with a comparison of the two flow configurations for absorption, with recommendations for their application in future miniaturization effortsen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectAbsorptionen_US
dc.subjectHeat transferen_US
dc.subjectWateren_US
dc.subjectAmmoniaen_US
dc.subjectMiniaturizationen_US
dc.subjectMass transferen_US
dc.subject.lcshHeat Transmission
dc.subject.lcshAir conditioning
dc.subject.lcshHeat pumps
dc.titleBinary fluid heat and mass exchange at the microscale in internal and external ammonia-water absorptionen_US
dc.typeDissertationen_US
dc.description.degreePhDen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.description.advisorCommittee Chair: Garimella. Srinivas; Committee Member: Fuller, Thomas; Committee Member: Graham, Samuel; Committee Member: Jeter, Sheldon; Committee Member: Koros, Williamen_US


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