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 42 for “"cycle efficiency"”.
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Development and application of a steady state code for supercritical carbon dioxide cycles
… for the most developed of the closed gas-turbine cycles (helium-Brayton), but at lower temperatures and higher pressures. The original in-house code, named CYCLES, could potentially be used by others who are researching the S-CO2 cycle, but it has its shortcomings. In particular, CYCLES does not …
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Performance and emission characteristics of natural gas combined cycle power generation system with steam injection and oxyfuel combustion.
Natural gas combined cycle power generation systems are gaining popularity due to their high power generation efficiency and reduced emission. In the present work, combined cycle power generation configuration systems studied with natural gas as primary fuel oxidizes with air and pure oxygen …
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Thermodynamic Analysis and Optimization of Supercritical Carbon Dioxide Brayton Cycles
… supercritical carbon dioxide (S-CO2) Brayton cycles present great promise particularly in high temperature concentrated solar power (CSP) and waste heat recovery (WHR) applications. With this regard, this dissertation is intended to perform thorough thermodynamic analyses and optimization of …
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Power conversion system design for supercritical carbon dioxide cooled indirect cycle nuclear reactors
The supercritical carbon dioxide (S-CO₂) cycle is a promising advanced power conversion cycle which couples nicely to many Generation IV nuclear reactors. This work investigates the power conversion system design and proposes several "Third Generation" plant layouts for power ratings ranging …
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Analysis of a supercritical hydrogen liquefaction cycle
… this work, a supercritical hydrogen liquefaction cycle is proposed and analyzed numerically. If hydrogen is to be used as an energy carrier, the efficiency of liquefaction will become increasingly important. By examining some difficulties of commonly used industrial liquefaction cycles, several …
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Process modeling and analysis of CO₂ purification for oxy-coal combustion
… additional energy consumption and lowers overall cycle efficiency. Purification options like traditional flue gas desulfurization (FGD), selective catalytic reduction (SCR), catalytic O₂ consumption, packed bed adsorption and low temperature flash separation have been proposed. In this thesis, we …
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Evaluation of an aluminum latent heat storage system for the fluoride-salt-cooled high-temperature reactor
… systems in terms of energy density, cost, and cycle efficiency. LHS systems use a phase change medium (PCM) that transfer heat at constant temperature. The use of metallic PCMs allows LHS to be used with high-temperature heat sources, such as the Fluoride-Salt-Cooled High- Temperature Reactor, …
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Analysis and optimization of a dual-load vapor compression cycle using non-azeotropic refrigerant mixtures
… characteristics which could improve cycle efficiency. A NARM experiences a variable temperature glide during a constant-pressure phase change process, making it a logical candidate for the two-temperature level cooling found in refrigerators. There are two fundamental thermodynamic …
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The Effect of Heat Transfer on Turbine Performance
… Fundamental questions, such as how turbine efficiency should be defined and which flow features reduce performance, remain unanswered. This thesis answers these questions and addresses the problem of how heat transfer affects turbine performance. Currently, there is a direct contradiction …
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Nuclear tanker producing liquid fuels from air and water
… option, it is feasible. Operating with a Rankine cycle, a PWR could power the recommended liquid fuel production plant with a 2,082 MWth reactor and 33% cycle efficiency. The recommended option uses a molten salt-cooled advanced high temperature reactor (AHTR) coupled to a supercritical carbon …
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Technical and economic feasibility of a high-temperature self-assembling battery
… of 10-15 years with >3,000 deep-discharge cycles, to require minimal maintenance, and to supply 1-5 A/cm2 at 0.9 V with 80% DC-DC cycle-efficiency.
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A solar reforming system for use in hybrid solar-fossil fuel power generation
… utilizing solar reforming in conventional power cycles has higher performance compared to other integration methods. In this thesis, a two level analysis of a hybrid redox redox cycle is performed. First, a system analysis of a hybrid cycle utilizing steam redox reforming is presented. Important …
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Analysis and optimization of the Graz cycle : a coal fired power generation scheme with near-zero carbon dioxide emissions
… and a number of oxy-fuel combustion schemes. One cycle design in particular, the Graz cycle, holds some promise as a future power generation cycle. A model of the Graz cycle developed in this paper predicts a cycle efficiency value of 56.72%, a value that does not account for efficiency losses in …
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Diffusional lithium trapping as a failure mechanism of aluminum foil anodes in lithium-ion batteries
… Scanning electron microscopy of cross-sectioned, cycled foils in the delithiated state reveals large regions of β-LiAl that are passivated by a surface layer of ⍺-Al, which has poor Li⁺ diffusivity. It is found that lithium diffusion occurs preferentially along the β-LiAl grain boundaries, so the …
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Techno-economic analysis of pressurized oxy-fuel combustion power cycle for CO₂ capture
… extensive research into new power generation cycles that enable carbon dioxide capture and sequestration. In this regard, oxy-fuel combustion is a promising new technology for capturing carbon dioxide in power generation systems utilizing hydrocarbon fuels. Combustion of a fuel in an …
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Evaluating Nuclear Energy Power Conversion Cycles for Microreactors
… size and cost of heat exchangers along with the efficiency of three simple power conversion cycles. Printed circuit heat exchangers with semi-circular channels were used in analysis due to their high power densities and low costs, making them extremely suitable for use with microreactors. A …
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The development of titanium nitride strengthened creep resistant ferritic steels
… resulted in a worldwide drive to increase the cycle efficiency of fossil fired power plant. Boiler designs able to achieve significant efficiency increases already exist; the limiting factor is the performance of materials. As a result, much effort is currently being focussed on the development …
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Thermofluid design and performance analysis of an air-cooled heat rejection system for a 50 MWe sCO2 concentrated solar power plant
… and efficient alternative to the current Rankine cycle based CSP plants. However, no such plant currently exists at the utility scale, and little is known about the heat rejection systems of such plants. If these plants are to be realised at a utility-scale, further research is required with …
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Design of compact intermediate heat exchangers for gas cooled fast reactors
… design optimizing economic and technical efficiency while coupling a supercritical CO2 Brayton power cycle to a helium cooled fast reactor core. In particular, the wavy channel friction factor and the effective conduction thickness between channels were evaluated by simulations using state …
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Thermal hydraulic design of a 2400 MW t̳h̳ direct supercritical CO₂-cooled fast reactor
… the reference GFR is a helium-cooled direct cycle plant with core outlet temperatures in the 850"C to 10000C range. Pursued in the interest of high cycle efficiency and the provision of process heat for hydrogen production by thermochemical water cracking, these high temperatures present …
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