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 169 for “"Refrigerant"”.
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Refrigerant distribution model development
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.
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Refrigerant charge reduction in small commercial refrigeration systems
This paper presents analysis of location of refrigerant inventory and numerical results of charge reduction in a typical bottle cooler. The original unit was first characterized by determining its capacity, the coefficient of performance (COP), pull-down characteristics, and total charge using …
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Thermodynamic optimization of evaporators with zeotropic refrigerant mixtures
ETDs are only available to UIUC Users without author permission
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Time-fractional analysis of flow patterns during refrigerant condensation
… conceptual design and basic layout of a modular refrigerant test system capable of flow condensation and evaporation were performed. The purpose of this study was the investigation of flow patterns during refrigerant condensation in intermittent flow in order to improve the prediction models. An …
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Experimental and analytical investigation of refrigerant and lubricant migration
The off-cycle refrigerant mass migration has a direct influence on the on-cycle performance since compressor energy is necessary to redistribute the refrigerant mass. No studies, as of today, are available in the open literature which experimentally measured the lubricant migration within a …
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Thermodynamic analysis of single-screw oil-flooded refrigerant compressors
… the performance of an oil-flooded single-screw refrigerant compressor are presented. The thermodynamic equations which are a basis for all the models are derived using a control volume approach. The mechanisms for power input to the oil are presented and three of these mechanisms, oil shear, oil …
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Rolling Contact Wear of Hybrid Ceramic Bearings with Refrigerant Lubrication.
… introduction of a new generation of hydrocarbon refrigerants in various systems, where these rolling contact silicon nitride bearing elements are employed raises further demands to evaluate the rolling contact fatigue performance of these elements with refrigerant lubrication. Obtaining material …
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A Study of Two-Phase Refrigerant Behavior in Flattened Tubes
… the tube include a substantial decrease in refrigerant mass, and a slightly decrease in overall tube length.
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Distribution of refrigerant and lubricant in automotive air conditioning systems
… is circulated throughout the system with refrigerant. At different oil concentrations, the circulating mixture exhibits different properties, which affects the characteristics of heat transfer, pressure drop and mass retention in each component. The purpose of this thesis is to measure and …
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Detection of refrigerant leaks with focus on low-GWP mixtures
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms
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Investigation of refrigerant flow-induced noise characteristics and mitigation approaches
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2026-12-01
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Evaluation and visualization of refrigerant two-phase flow in distributor
… inlet quality, and orientation are studied. Refrigerant mal-distribution is quantified by comparing mass flow rate, quality, and cooling capacity in each circuit. To make the experiment results more applicable to real system, several aspects in this facility which are not exactly the same …
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Experimental investigation of an ejector as a refrigerant expansion engine
The use of an ejector to improve the performance of a vapor compression refrigeration system was investigated. The ejector harnesses kinetic energy developed during the throttling process and returns it to the compressor in the form of a pressure boost. An ejector was designed taking into account …
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Flashing flow of refrigerant HFC-134a through a diabatic capillary tube
… refrigeration system that normally supplied refrigerant with or without oil to the capillary tube, while providing easily controlled boundary conditions. Pressures and temperatures along the capillary tube and suction line were also instrumented. The capillary tube was tested for a wide range …
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Adiabatic Developing Two-Phase Refrigerant Flow in Manifolds of Heat Exchangers
Experiments were performed using R134a in a facility designed for visualization (PDPA, photo) and two-phase flow distribution measurements for various inlet tube and flow characteristics. For most experiments, a transparent manifold in simplified geometry was used. Further experimental analysis is …
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An experimental study of the flow boiling of refrigerant-based nanofluids
… with CO2 and R134a used as the base refrigerants. CuO nanoparticles 40nm in size, and TiO2 nanoparticles 200nm in size are used to create partially stable CO2-based nanofluids. Stable nanofluids are created in R134a by mixing it with dispersions of surface-treated nanoparticles in …
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Refrigerant flow distribution in vertical headers of reversible microchannel heat exchangers
… pump mode, it functions as an evaporator and refrigerant maldistribution among parallel microchannel tubes creates unwanted superheated region, which lowers the heat transfer between refrigerant and air. This thesis presents the experimental and modeling study of refrigerant distribution in …
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Experimental investigation of cavitation using refrigerant in a two-phase flow system
… reduction. In this thesis, cavitation of R134a refrigerant is evaluated experimentally. This work is part of an ongoing project that seeks to develop a novel cooling cycle based on the cooling potential of the fluid during cavitation. A blowdown system was designed, built, and used for …
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Heat transfer performance and prediction of low global warming potential R134a refrigerant alternatives
… phasing out high global warming potential (GWP) refrigerants such as R134a. Since many potential alternative refrigerants have flammability and cost concerns, minimizing system charge is critical. The condenser is typically responsible for 50% of the charge of a system; it is vital to have a …
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Tribology of engineering and coated materials in the presence of environmentally friendly refrigerant
… has been devoted towards finding of alternative refrigerants due to environmental issues related to high global warming potential (GWP). Specifically, developing a system-compatible alternative refrigerant is of prime concern in order to reduce costs associated with design modifications. Among …
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