Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Refrigeration Cycle"”.
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The design and testing of a vapour pump in the absorption refrigeration cycle
… presents a new pumping method in absorption refrigeration. A vapour pump, powered by a fraction of the high pressure refrigerant, is proposed to replace the conventionally used electric pump. The only energy required to power the cycle is the heat supplied to the generator. The system thus …
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The Development of a Semi-Open Refrigeration Cycle for the Crystallisation of Aqueous Salts
The development of a Semi-Open Refrigeration Cycle had been shown to be of economic value to the process of crystallisation. The experimentation took the form of several bench scale experiments to develop the designs of the individual vessels that were to constitute the final pilot …
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Evaluating energy dissipation during expansion in a refrigeration cycle using flue pipe acoustic resonators
… to achieve greater cooling power from a cryorefrigeration cycle. Two models of the acoustic operation of flue pipe resonant systems are examined: an electrical circuit analog that represents the linear approximation of the acoustic system and a numerical model based on empirical data. The …
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Motor vehicle air-conditioning : utilising the exhaust gas energy to power an absorption refrigeration cycle
… by replacing the traditional compression refrigeration system, used for air-conditioning a motor car, with an absorption unit. The thesis deals with some theoretical aspects of the absorption refrigeration cycle as well as practical aspects of motor car air-conditioning. A fair amount of …
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Processes Involving Acid Gas Solubility In Room Temperature Ionic Liquids (RTILs)
… processes: membrane separation and absorption refrigeration cycles. The first part of this study investigated the separation of a mixed dry gas feed of CO2/CH4 by four Stabilized Ionic Liquid Membranes (SILMs); 1-Ethyl-3-methlyimidazolium dicyanamide, [emim][DCA], 1-ethyl-3-methylimidazolium …
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Nanoscale thermal systems in subcritical region
… thermal systems in subcritical thermodynamic cycles. A nanoscale vapor heat engine shows a lower efficiency than the macroscale vapor heat engine and the coefficient of performance for a nanoscale refrigeration cycle is higher than that for a macroscale refrigeration cycle.
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The determination of the viscosity of liquid carrene-7, an azeotropic mixture of dichlorodifluoromethane and asymmetrical difluoroethane
… method of preserving perishable materials is by refrigeration. Refrigeration generally means the removal of heat from a body or substance to such an extent as to leave it, or maintain it, at a lower temperature than that of the surroundings. Mechanical refrigeration refers to the removal of heat …
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Comparison of refrigerants R410a and R404a for use in low temperature applications: A computer model study
… results for this exact in-house laboratory refrigeration system. Complimenting the experimental results, the EES model simulates the refrigeration cycle for each refrigerant at four different settings of ambient air temperature into the condenser. The EES model results are compared in graphs …
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Testing and modeling of a two-phase ejector
The ejector expansion refrigeration cycle is a modified vapor compression cycle in which a two phase ejector is used to recover a portion of the work otherwise lost in the expansion valve. The ejector improves cycle performance by increasing compressor inlet pressure and by lowering the quality of …
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Experimentally validated models of refrigerant distribution in microchannel heat exchangers used to evaluate charge reduction of various working fluids
… specified percent decrease in COP from the same refrigeration cycle with no pressure drop. Furthermore, the effect of mass flux on charge is studied and discussed. Lastly, prediction of charge in headers is explored and correlations for predicting charge in headers of microchannel condensers are …
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Enhanced condensation with active methods
… in liquefied natural gas processing and refrigeration systems. Current state of the art low surface energy low hysteresis coatings are not able to achieve dropwise condensation below 10 mN/m. Surface acoustic waves are proposed as an active method to shed thin condensate films to reduce …
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The design of a high pressure solvent extraction process using liquid ammonia as solvent
… of an evaporator, compressor and condenser in a refrigeration cycle. Two systems were selected for study, Cumene-n-Heptane-Ammonia and Toluene-Methylcyclohexane-Ammonia. Equlibrium data for the first system was determined experimentally in a specially-designed, equilibrium bomb. A technique was …
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Measurement of the efficiency of a flashing flow nozzle
… energy at the nozzle exit. A vapor compression refrigeration cycle using refrigerant R-12 was employed to test the nozzle. Use of a bubble seeding device upstream of the nozzle to provide nucleation sites in the flow was expected to decrease the non-equilibrium, therefore producing an increase …
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A Computational Model for Two-Phase Ejector Flow
… of an effort to develop the ejector expansion refrigeration cycle, a device which increases performance of a standard vapor compression cycle by replacing the throttling valve with a work-producing ejector. Experimental results have confirmed the performance benefit of the ejector cycle, but …
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Experimental and Analytical Investigation of a Two-Phase Ejector Used for Expansion Work Recovery in a Transcritical R744 Air-Conditioning System
… of the transcritical carbon dioxide (CO2, R744) refrigeration cycle, the supercritical heat rejection pressure can be used to maximize the system performance. In addition, large throttling losses make R744 a suitable fluid for expansion work recovery. This study presents experimental and …
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Investigation of energy storage options for thermal management in hybrid electric vehicles
… management system is integrated with the active refrigeration cycle. The overall exergy efficiency of the system with PCM presence is 31%. In addition, results obtained by sing EES program show that an increase in PCM mass fraction results in an increased exergy efficiency of the system which is …
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Dynamic Modeling and Model-Free Real-Time Optimization for Cold Climate Heat Pump Systems
… operation of ASHP over the single-stage refrigeration cycle, such as vapor injection techniques and cascade configuration. However, there has been a lack of effective control strategies for such systems to maintain the optimal energy efficiency for operations across different combinations …
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Elastocaloric properties of Natural Rubber for Solid-State Cooling Technologies
… crystallization. Nevertheless, research on the refrigeration potential of natural rubber is still in its infancy, and not all parameters influencing the elastocaloric behaviour of this material are fully understood. In particular, most studies so far have focused primarily on the influence of …
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Análise teórico-experimental do coeficiente de perfomance (COP) de um sistema de refrigeração por jato-compressão
… and experimental study of a new intermittent refrigeration system ejector cycle characteristics, with use of waste heat. Initially, was doing a bibliographical survey about the vapor ejector refrigeration system technology. In the following stage was doing a simulation of the corresponding …
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