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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 76 for “"Refrigerants"”.
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Flash gas bypass concept utilizing low pressure refrigerants
Flash gas bypass represents one of the prospective approaches to improve the efficiency of various small scale heat transfer systems that utilize refrigerant as a working fluid. It is characterized by the bypass of vapor created throughout the expansion process around the evaporator. As the …
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Sustainable design of hydrocarbon refrigerants applied to the hermetic compressor
… and phase out of traditional chlorofluorocarbon refrigerants (CFCs) under the terms of the Montreal protocol. CFCs used in domestic applications were initially replaced with hydrofluorocarbons (HFCs) such as R134a which has a zero ozone depletion potential (ODP). The use of HFCs has also come …
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Sustainable development of refrigerator systems using replacement environmentally acceptable refrigerants
… led to the phase out of chlorofluorocarbon (CFC) refrigerants from the domestic refrigeration industry. One intriguing aspect is that the chlorine in CFCs is a good lubricating agent and any deterioration of system performance may adversely influence other environmental considerations. Based on …
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Investigation of the condensing and expansion behaviors of alternative refrigerants
… tube study examined the mass flow rate of refrigerants while expanding, with an emphasis on the nature of the metastable region for both single component refrigerants and mixtures.
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Experiments In Pool Boiling Heat Transfer And Nucleationdynamics Of High Pressure Refrigerants
… of studying the physics and thermodynamics of refrigerants under nucleate pool boiling. The main objective of this experiment was the design of the experimental setup. Various designs were tested and validated, of which all incorporated a pressure resistant chamber constructed out of aluminum …
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Impact of alternative refrigerants on evaporator design and analysis of compact heat exchangers
… with the evaluation of the impact of alternate refrigerants on the thermal design parameters of different heat exchangers, such as, plate fin and tube, shell and tube evaporator and compact heat exchangers. A computer code has been developed in Quick-Basic language to conduct this investigation.
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Polynuclear 3d/4f-Metal Complexes as Molecular Magnetic Refrigerants and Single-Molecule Magnets
The use of two different chelating/bridging ligands, naphthalene-2,3-diol (ndH2) and acenaphthenequinone dioxime (acndH2), in heterometallic 3d/4f-metal cluster chemistry has yielded two new families of polynuclear CuII/LnIII clusters. These complexes were found to exhibit interesting magnetic …
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Analytical and experimental investigation of two-phase ejector cycles using low-pressure refrigerants
The standard two-phase ejector cycle has received significant attention in research studies in recent years because of its ability to improve the efficiency of refrigeration cycles. However, there are several alternate two-phase ejector cycles that have been proposed but have received little …
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Convective boiling of refrigerants near the micro-macroscale transition inside plate heat exchangers
This work focuses on the refrigerant flow morphology and its impact on evaporative heat transfer and pressure drop during plate heat exchanger (PHE) operation at low mass flux conditions. While there is interest in this operating regime in the heating, ventilating, air conditioning, and …
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Heat transfer and flow characteristics of condensing refrigerants in small-channel cross-flow heat exchangers
… to perform the same task. Since the cost of refrigerants continues to rise due to the phase out of chlorofluorocarbons (CFCs), internal volume becomes a key design parameter.
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Flow condensation of low GWP refrigerants inside smooth and micro/nano-structured macro/mini channels
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01
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Assessment of the environmental acceptability of refrigerants by discrete mathematics: cluster analysis and Hasse diagram technique
… of chlorofluorocarbons (CFCs), mainly used as refrigerants, has lead to look for environmentally acceptable CFC replacements. Main environmental concern CFCs face is their ability to deplete the stratospheric ozone layer, quantified by the ozone depletion potential (ODP). Some of the first …
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Two-Phase Pressure Drop and Flow Regime of Refrigerants and Refrigerant -Oil Mixtures in Small Channels
… regime. Two-phase pressure drop data for four refrigerants (R134a, R410A, R290 and R717) were measured in a channel with hydraulic diameter of 148 mum. These data were combined with previous two-phase data of R134a in small channels (hydraulic diameters ranging from 70 to 300 mum) to generate a …
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Comparison of refrigerants R410a and R404a for use in low temperature applications: A computer model study
… need for efficient and environmentally friendly refrigerants in low temperature applications. This study provides a perspective for comparison of refrigerant R410a with R404a. As R410a is now widely used commercially, further knowledge is desired on how different an R410a system is from …
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Design, Testing And Controls For Air Source Heat Pump System In Cold Climates Using Natural & Conventional Refrigerants
… use various types of hydrofluorocarbons (HFC) refrigerants which are also responsible for greenhouse gas emissions. Therefore, natural refrigerant such as which is naturally available, eco-friendly, non-toxic, non-flammable, and non-corrosive can be a good alternative to the HFC refrigerants. …
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Scuffing and wear of engineering materials under different lubrication regimes in the presence of environmentally friendly refrigerants
… industry has been focusing on alternative refrigerants for the replacement of hydrofluorocarbons (HFCs) due to environmental regulations. HFCs refrigerants have been widely used in the refrigeration industry since the early 1990’s as replacement to chlorofluorocarbon (CFCs) refrigerants …
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Performance optimization of advanced vapor compression systems working with low-GWP refrigerants using numerical and experimental methods
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-05-01
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Development of nano composite coatings for enhanced performance in non-conventional lubricants under sliding contact.
… the development, formulation and use of various refrigerants in the thermodynamic cycle. Most of the refrigerants that are used in domestic appliances, commercial buildings, small scale industrial applications and automobiles are artificially formulated. Although artificially formulated …
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Comparative Life Cycle Assessment of CFC-replacement Compounds in Different Technical Applications
… as an example for technical application of refrigerants. The environmental impacts due to life cycles of different possible substitute refrigerants are compared with the presently used 1,1,1,2-tetrafluoroethane (R134a). Additional refrigerants included in this study comprise dichloromethane …
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