Dissertations / Theses on the topic 'Electric and gas heating'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Electric and gas heating.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Míková, Šárka. "Vytápění bytového komplexu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227537.
Full textLadomérská, Jana. "Vytápění objektu zdroji na různé druhy paliv." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227584.
Full textBarufi, Clara Bonomi. "Identificação de barreiras para a ampliação do uso de gases combustíveis para aquecimento de água no setor residencial." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-29102008-124300/.
Full textThis research is motivated by the verification that the installation of gas based water-heating systems in new apartments may be cheaper than the use of electric systems. It is also motivated by the perspectives of a growing supply of natural gas in the country. Considering these points and the perspective of general growing use of electricity, this research identifies barriers to expand the use of gas based systems, suggesting ways to overcome those barriers. Considering that the energy uses in an apartment are largely affected by decisions taken during the construction of the building, the study is based on a field research developed through interviews with construction agents. It also includes a definition on the residential energy use, which details the gas (natural gas and LPG) market evolution, the historically reduced use of these fuels in water-heating systems, and the perspectives of rising supply of natural gas in Brazil. It also describes the use of hot water to hygiene, considering the main systems available in São Paulo. This context is completed by the perspectives related to the increase of electricity demand and the current real estate market development. The research concludes that gas based water-heating systems are already extensively used in São Paulo. This development is related to the mandatory use of those systems in some apartment configurations, the users demand for comfort, and the 2001 electric power shortage. On the other hand, it shows that electric showers are still largely used in building of poorer families. Since this segment has the largest demand for new houses in the country, there is space to substitute energy consumed for thermal purposes with the direct use of gas.
Jurka, Vít. "Návrh vytápění z pohledu primární energie." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226837.
Full textNovik, Frode Karstein. "Power system for electric heating of pipelines." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8936.
Full textDirect electrical heating (DEH) of pipelines is a flow assurance method that has proven to be a good and reliable solution for preventing the formation of hydrates and wax in multiphase flow lines. The technology is installed on several pipelines in the North Sea and has become StatoilHydros preferred method for flow assurance. Tyrihans is the newest installation with 10 MW DEH for a 43 km pipline. However, the pipeline represents a considerable single-phase load which makes the power system dependent on a balancing unit for providing symmetrical conditions. This limits the step out distance and is not suitable for subsea installation. Aker Solutions has proposed several specially connected transformers for subsea power supply of DEH systems, Scott-T being one of them. The Scott-T transformer is a three-to-two-phase transformer which provides balanced electrical power between the two systems when the two secondary one-phase loads are equal. By implementing this transformer, it can be possible to install the power supply subsea as there is no need for a balancing unit. In addition, the system may be applicable for long step out distances. This is because the pipeline is inductive and can use the reactive power produced by the long cable which also can increase the critical cable length. There are however some limitations on this system using the Scott-T transformer. There is a large variation in the magnetic permeability between individual joints of the pipeline. This can result in different load impedance of the two pipe sections connected to the Scott-T transformer. The result is unbalance in the power system. The method of symmetrical components is applied to investigate the behavior during unbalanced loading of the Scott-transformer. The relationship between the negative- and the positive sequence component of the current is used to express the degree of unsymmetry. For the simulations in SIMPOW, the Scott-T transformer is modelled by the use of Dynamic Simulation Language. The simulations on the DSL model give correct and reliable results for analysing the the degree of unsymmetry in the Scott-T transformer. When the load impedance of one pipe section is varied, simulation proves that it can change between 0.75 and 1.34 per unit of the other pipe impedance. The Scott-T transformer does still provide electrical power between the two systems which is below the limit for the degree of unsymmetry (15%). Case 1 and Case 2 introduce two possible configurations for a subsea DEH system with the Scott-T transformer implemented. The configurations include an onshore power supply which is connected to a subsea power system for direct electrical heating and a subsea load at the far end of the subsea cable. The pipeline in Case 1 is 100 km long and is divided into two pipe sections of 50 km which are connected to a Scott-T transformer. The pipeline in Case 2 is 200 km long and is divided into four pipe sections of 50 km each. There are two Scott-T transformers in Case 2. For normal operation of the subsea load (50 MW, cosfi=0.9) and heating the pipe content from the ambient sea emperature, the results indicate that tap changers are necessary to keep the Scott-T transformers secondary terminal voltage at 25 kV. This meets the requirement in both cases for heating the pipe content from 4 to 25 degrees celsius within 48 hours after a shutdown of the process. The degree of unsymmetry is zero for both cases when the system is operated as normal. However, all system simulations indicate that reactive power compensation has to be included for Case 1 as well as for Case 2 in order to have a power factor of unity at the onshore grid connection. The fault scenarios indicate that the degree of unsymmetry is dependent on both the type of fault and the power supply in the system. For Case 1, the relationship (I-/I+) is only of 3.3% in the subsea cable when there is a short-circuit at DEHBUS3, but as much as 87% at the grid connection. The degree of unsymmetry in the Scott-T transformer is then 67%. This is far beyond the limit for maximum negative sequence component of 15%. The significant unsymmetry in the line between the grid and BUS1 is most likely due to the large power delivered to the fault. During the fault, the reactive power delivered to the system increases from 10.6 Mvar to 131.9 Mvar after the fault, but the active power increases only from 75.2 MW to 87.1 MW. This means that it is most likely the reactive power that contributes to the consequent unsymmetry and negative sequence component of the current. There are two Scott-T transformers installed in Case 2. If the DEH system is only heating the pipe section closest to shore (at DEHBUS33), simulations show that the three-phase power system becomes unsymmetric which results in different phase currents. The degree of unsymmetry at the grid connection is 32% when only the pipe section at DEHBUS33 is heated. In addition, the unbalance in the three-phase system caused by SCOTT1 involves unbalance in the SCOTT2 transformer as well. The load voltages are not equal in magnitude and dephased of 90 degrees for this mode, but are 32 kV and 35 kV respectively and dephased of 88 degrees. This concludes a very important behavior of the Scott-T transformer. The simulations conclude that the Scott-T transformer provides symmetrical conditions for both configurations when the two load impedances are equal. However, Case 2 shows an important result when installing two Scott-T transformers in the same system. Unbalanced loading of one of the specially connected transformers gives unsymmetrical conditions in the three-phase system which results in unbalanced load voltages for the other Scott-T transformer. The analysis is limited to the configurations given for Case 1 and Case 2, but shows typical results when an alternative transformer connection is implemented in a DEH system.
Madhavi, S. "Carrier Mobility And High Field Transport in Modulation Doped p-Type Ge/Si1-xGex And n-Type Si/Si1-xGex Heterostructures." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/294.
Full textSaraiva, José Carlos. "Custo das opções para o aquecimento de água na habitação de interesse social em São Paulo - CDHU." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-19072012-110713/.
Full textThe paper uses research as investigative and experimental method to identify the factors responsible for the definition of infrastructure for bathing water heating (gas, electric and solar thermal) in residential buildings of popular interest, built in São Paulo. Based on the information from three projects and the sizing of the infrastructure of each of them, the costs for a typical project exclusively for bathing water heating, are determined. Besides that, are also determined, the costs of acquisition, installation, infrastructure and operation of each configuration. The method - Life Cycle Cost Analysis (LCCA) is used to compare the various financial alternatives. The results allow to evaluate the interest in carrying out infrastructures combined to enable anytime instant use of appliance, electric or gas, with or without the solar thermal support. This combined infrastructure allows the user free choice, individually and at any time, for heating water for bathing, in view of its cost benefit, possibly combined with the opportunities offered by energy distributors and / or the device manufacturers and / or public policy. The results present relevant data to support comparative discussion and analysis, setting ways to guide the choice of infrastructure.
Holth, Erik. "Model Predictive Control of mixed solar and electric heating." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9106.
Full textIn this report we will model a heat system consisting of a heat storage tank and an application. The heat storage tank is supplied by a heating element and heated water from a solar collector. The main objective of the heat system is to mainatian a reference temperature in the application (a house). Weather forecasts will be used as weather data affecting the heat system. We will assume that the weather forecasts and the actual weather will be the same. The heat sytem will consist of simplified nonlinear differential equations and be controlled by a model predictive controller (mpc). The mpc controller will use a linearized model of the nonlinear process. The average predicted outside temperature from the weather forecasts will be used as nominal value for the same temperature in the linearized model in the mpc controller. The mpc controller will measure some disturbances to make more efficient control. The most imortant disturbance will be the temperature of the water coming out of the solar collector, that will flow into the heat storage. By measuring this temperature, the mpc controller can apply it to its predictor and make sure that the power of the heating element in the heat storage is reduced when solar collector heated water is available. This is to make sure that the heat storage has enough capacity to receive the heated water from the solar collector, while still maintaining a reasonable temperature in the heat storage. Simulation with different weighting of the inputs in the mpc controller will show that heating element power consumption is influenced by these weights.
Hinchliffe, Stephen. "Solid-state high-frequency electric process heating power supplies." Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/32518.
Full textSoderlund, Matthew Roger. "Congeneration dedicated to heating and cooling." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17672.
Full textWongsa-Ngasri, Pisit. "Ohmic heating of biomaterials: peeling and effects of rotating electric field." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1078447669.
Full textLeung, Tommy (Tommy Chun Ting). "Coupled natural gas and electric power systems." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98547.
Full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 235-240).
Scarce pipeline capacity in regions that rely on natural gas technologies for electricity generation has created volatile prices and reliability concerns. Gas-fired generation firms uniquely operate as large consumers in the gas market and large producers in the electricity market. To explore the effects of this coupling, this dissertation investigates decisions for firms that own gas-fired power plants by proposing a mixed-integer linear programming model that explicitly represents multi-year pipeline capacity commit- ments and service agreements, annual forward capacity offers, annual maintenance schedules, and daily fuel purchases and electricity generation. This dissertation's primary contributions consist of a detailed representation of a gas-fired power-plant owner's planning problem; a hierarchical application of a state-based dimensionality reduction technique to solve the hourly unit commitment problem over different tem- poral scales; a technique to evaluate a firm's forward capacity market offer, including a probabilistic approach to evaluate the risk of forced outages; a case study of New England's gas-electricity system; and an exploration of the applicability of forward capacity markets to reliability problems for other basic goods.
by Tommy Leung.
Ph. D.
Ojha, Abhi. "Coupled Natural Gas and Electric Power Systems." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78666.
Full textMaster of Science
Marcotte, Michèle. "Ohmic heating of viscous liquid foods." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ55357.pdf.
Full textSilva, Edson Batista da. "Performance analysis of gas turbine opeerating with low heating value fuels." Instituto Tecnológico de Aeronáutica, 2012. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2215.
Full textWang, Kaiyang. "Ring opening polymerisation of ɛ-caprolactone using microwave electric and magnetic heating." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49540/.
Full textБоянівський, Владислав Петрович. "Підвищення ефективності печей для переплавки алюмінієвого брухту." Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/24376.
Full textMaster's dissertation on "Improving the efficiency of furnaces for aluminum scrap remelting": 104 p., 35 f., 12 tables, 4 applications, 15 sources. The object of the study is an oven for aluminum scrap remelting. The purpose of the work is to increase energy efficiency and improve the design of furnaces for aluminum scrap remelting. Analyzed the main ways of improving energy efficiency. Presented the results of calculations of the energy efficiency of a 6-ton capacity kiln with a capacity of 600 kW for the remelting of aluminum scrap. It is shown that due to reduction of the opening time of the firebox, the cost of the supplied heat in the furnace decreased by 45% and due to the change of the thermal insulation layers - by 21%. Selected gas-fired devices - burners type GPP-5 and the scheme of their placement in the side of the front wall of the furnace. The calculations of the energy and economic efficiency of the furnace conversion from the electric heating to the gas have been performed, while for the gas heating the costs of the supplied heat are reduced by 9 - 10% in comparison with the electric one. Calculations have shown that the use of gas heating compared to electric is economically more efficient, since the cost of natural gas in the melt cycle for a 600 kV upgraded furnace decreases by about 10%. Developed the furnace design with an inclined vault for which the average melting time decreases by 11% compared to the traditional one, and the efficiency increases by 7%. For utilization of flue gases heat was chosen one-sided-needle metal recuperator for heating of blown air with the area of the heating surface 12 m2. As a result of the installation of the recuperator, the temperature of the flue gases is reduced from 800 °C to 390 °C, while the ambient air temperature rises from 20 ° C to 350 C. The amount of fuel savings is 16.9 %. Based on the Solid Works software, constructed geometric models of the multilayer walls of the furnace and obtained the results of the distribution of temperature fields along the thickness of the enclosing structures. The presented results are comparable to the experimental data obtained on real furnaces. Made provision for safe and comfortable work in the premises of a research laboratory and fire and safety measures in emergencies. A startup project based on the Business Model Canvas template has been developed.
Магистерская диссертация на тему «Повышение эффективности печей для переплавки алюминиевого лома» 104 с., 35 рис., 12 табл., 4 приложения, 15 источников. Объект исследования - печь для переплавки алюминиевого лома. Цель работы - повышение энергетической эффективности и совершенствование конструкции печей для переплавки алюминиевого лома. Проанализированы основные способы повышения энергетической эффективности. Приведены результаты расчетов энергетической эффективности печи вместимостью 6 т, мощностью 600 кВт, для переплавки алюминиевого лома. Показано, что за счет уменьшения срока открытия форкамер снизились расходы подведенной теплоты в печи на 45%, а за счет изменения теплоизоляционных слоев - на 21%. Выбраны газосжигающие устройства - горелки типа ГПП-5 и приведена схема их размещения в боковой передней стенке печи. Выполнены расчеты энергетической и экономической эффективности перевода печи с электрического нагрева на газовый, при этом для газового нагрева расходы подведенной теплоты уменьшаются на 9 - 10% по сравнению с электрическим. Расчетами установлено, что использование газового нагрева по сравнению с электрическим экономически более эффективно, поскольку затраты на природный газ в цикле плавки для модернизированной печи мощностью 600 кВт уменьшаются примерно на 10%. Разработана конструкция печи с наклонным сводом, для которой по сравнению с традиционным уменьшается срок плавки в среднем на 11%, а КПД повышается на 7%. Для утилизации теплоты дымовых газов выбран односторонне-игольчатый металлический рекуператор для подогрева дутьевого воздуха с площадью поверхности нагрева 12 м2. В результате установки рекуператора температура дымовых газов снижается от 800 °С до 390 °С, при этом температура дутьевого воздуха повышается от 20 °С до 350 °С. Величина экономии топлива составляет 16,9%. На базе программного обеспечения Solid Works построены геометрические модели многослойных стенок печи и получены результаты распределения температурных полей по толщине ограждающих конструкций. Приведены результаты сопоставимы с экспериментальными данными полученными на реальных печах. Предусмотрены меры по безопасной и комфортной работе в помещении научно-исследовательской лаборатории. Разработан стартап-проект по шаблону Business Model Canvas.
Boswell, Michael John. "Gas engines for domestic engine-driven heat pumps." Thesis, Oxford Brookes University, 1992. http://radar.brookes.ac.uk/radar/items/37f7ed18-4b86-6ab3-8ba6-1c27947fb1ce/1.
Full textPaterson, Lindsay Jane. "An investigation of soil heating by natural gas pipelines in southern Ontario." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ55700.pdf.
Full textChung, Tse-Ming. "Prediction of zone temperatures, cooling loads and illuminances from numerical simulation of the interaction between fluorescent lighting and HVAC systems." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/33238.
Full textLilly, Dana Elizabeth. "Analysis and performance of gas-electric hybrid chiller systems." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/15996.
Full textFarnsworth, Kimberly Dawn Richards. "Variable frequency microwave curing of polymer dielectrics." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/10928.
Full textLindquist, Charlie. "Flue gas heat recovery for district heating : Analysis of flue gas condensation on a crematorium facility at Hovdestalund, Västerås." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-54759.
Full textSai-man, Leung Alfred. "Measured and simulated light losses in furnished interiors lit by electric lighting." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243242.
Full textSimon, M. J. "The thermal performance of water cooled panels in electric arc steelmaking furnaces." Thesis, Sheffield Hallam University, 1989. http://shura.shu.ac.uk/20363/.
Full textPolyzakis, Apostolos. "Technoeconomic evaluation of trigeneraton plant: Gas turbine performance, absorption cooling and district heating." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/1832.
Full textTanikella, Ravindra V. "Variable frequency microwave processing of materials for microelectronic applications." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/10271.
Full textWendelstorf, Jens. "Ab initio modelling of thermal plasma gas discharges (electric arcs)." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961148527.
Full textDavies, Mark H. "Numerical modelling of weld pool convection in gas metal arc welding /." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phd2563.pdf.
Full textSmailes, Allan J. "Thermal modelling of gas metal arc welding using finite element analysis /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09ENS/09enss635.pdf.
Full textDurham, Emily Kilpatrick. "Moderate Electric Field Treatment for Saccharification of Cellulosic Materials." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1431082825.
Full textDalla, Silvia Carla. "Modelling of minority ion kinetics in tokamak plasmas during ion cyclotron resonant heating." Thesis, London South Bank University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245069.
Full textCherukupalli, Sudhakar Ellapragada. "Surface charge accumulation on spacers under switching impulses in sulphur hexafluoride gas." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26973.
Full textApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Reniers, Jorn. "Analysis of a real-time signal for greenhouse gas emissions of district heating consumption." Thesis, KTH, Industriell ekologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-169508.
Full textCross, Richard Barrie Michael. "Low temperature (<150°C) hydrogenated amorphous silicongrown by PECVD with source gas heating." Thesis, De Montfort University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502097.
Full textPolyzakis, Apostolos L. "Technoeconomic evaluation of tri-generation plant : gas turbine performance, absorption cooling and district heating." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/1832.
Full textContreras, Jesse Alberto. "Axial Temperature Gradients in Gas Chromatography." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2645.
Full textKamanzi, Janvier. "Thermal electric solar power conversion panel development." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2527.
Full textThe world has been experiencing energy-related problems following pressuring energy demands which go along with the global economy growth. These problems can be phrased in three paradoxical statements: Firstly, in spite of a massive and costless solar energy, global unprecedented energy crisis has prevailed, resulting in skyrocketing costs. Secondly, though the sun releases a clean energy, yet conventional plants are mainly being run on unclean energy sources despite their part in the climate changes and global warming. Thirdly, while a negligible percentage of the solar energy is used for power generation purposes, it is not optimally exploited since more than its half is wasted in the form of heat which contributes to lowering efficiency of solar cells and causes their premature degradation and anticipated ageing. The research is geared at addressing the issue related to unsatisfactory efficiencies and anticipated ageing of solar modules. The methodology adopted to achieve the research aim consisted of a literature survey which in turn inspired the devising of a high-efficiency novel thermal electric solar power panel. Through an in-depth overview, the literature survey outlined the rationale of the research interest, factors affecting the performance of PVs as well as existing strategies towards addressing spotted shortcomings. While photovoltaic (PV) panels could be identified as the most reliable platform for sunlight-to-electricity conversion, they exhibit a shortcoming in terms of following the sun so as to maximize exposure to sunlight which negatively affects PVs’ efficiencies in one hand. On the other hand, the inability of solar cells to reflect the unusable heat energy present in the sunlight poses as a lifespan threat. Strategies and techniques in place to track the sun and keep PVs in nominal operational temperatures were therefore reviewed.
Prior, J. J. "A new multi-tracer gas technique for measuring interzonal air flows in buildings." Thesis, University of Westminster, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372387.
Full textŠťastný, Radek. "Technická zařízení budov v budovách s téměř nulovou spotřebou." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265411.
Full textNikopoulos, Achilles. "Design and energy analysis of a hybrid electric natural gas vehicle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40218.pdf.
Full textAgelii, Harald. "Dipole Orientation of Gas Phase Ubiquitin Using Time Dependent Electric Fields." Thesis, Uppsala universitet, Molekyl- och kondenserade materiens fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-415340.
Full textKaptain, Tyler J. "Hardware Scaled Co-Simulation of Optimal Controlled Hybrid Gas-Electric Propulsion." Cleveland State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=csu1631634390032462.
Full textKamal, Rajeev. "Optimization and Performance Study of Select Heating Ventilation and Air Conditioning Technologies for Commercial Buildings." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6656.
Full textYuan, Qiulin. "Studies of electric discharges and their interactions with gases." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/22086.
Full textZavattoni, Laëtitia. "Conduction phenomena through gas and insulating solids in HVDC gas insulated substations, and consequences on electric field distribution." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT063/document.
Full textThe emergence of renewable energy leads to a development of new technologies for energy distribution across long distances. The latter will be based on High Voltage Direct Current (HVDC) to avoid capacitance losses. This network is interconnected using Gas Insulated Substation (GIS), which insulation is composed of pressurized gas (SF6) and solid insulators (epoxy resin), which have to withstand HVDC. The electric field is not anymore determined by permittivity of materials, but by resistivities and charge accumulation. In the case of an insulator with an interface with gas, electrons or ions will move across electric field lines and will charge the surface of the solid insulator. The behavior of insulator's properties (gas and solid) constitutes a major challenge for the development of HVDC GIS, to understand the charge relaxation/accumulation mechanisms.In this work, the characterization of solid insulator has first been investigated, based on a low-noise current measurement method. It is thus possible to measure the leakage current through samples and onto their surface, in a pressurized gas, at high electric field and for different temperatures. Those measurements permit to evidence that both volume and surface resistivities are strongly impacted by the increase of temperature and water concentration. It has also been shown that surface resistivity has a non-linear behavior with electric field. A numerical model was developed, to simulate experimental results, showing that the surface properties of the insulator can be implemented.Furthermore, the insulating properties of the gas were also investigated through different electric field geometry (coaxial and uniform), in order to estimate the contribution of current through gas on the charge accumulated on solid insulators. It has been found that a non-negligible current passes through the gas (~pA to nA). To determine the mechanisms responsible for such currents, the latter has been characterized depending on several parameters (electrode surface roughness, material nature, electric field, temperature and relative humidity). It revealed that the variations of currents are strongly impacted by the conditioning of the device and thus by the relative humidity adsorbed on electrodes and enclosure surfaces. In presence of a dry system (dry gas and device) low current were measured (~pA), which increases with temperature. On the contrary, in case of a “wet” system (humid gas and device) the current decreases with increasing temperature. Those results combined with the influence of the electrode roughness, strongly suggest a mechanism of charge injection at the electrode surface, enhanced by water adsorption.Finally, the results obtained for both solid and gaseous insulations are used to develop a numerical model with a shape close to the industrial application, and observe the modification of electric field distribution in presence of water concentration and temperature gradient. An estimation of current flowing through the insulator and gas is thus possible in case of uniform and gradient temperature.In conclusion, this work gives the variations of both volume and surface resistivities in an epoxy resin with temperature and electric field. It also evidences the major influence of relative humidity and temperature on charge injection mechanisms which contribute to the current measured through gas. The extensive characterization performed, enables to develop a simulation which predicts the variations of electric field distribution within an HVDC GIS
Byerley, Aaron R. "Heat transfer near the entrance to a film cooling hole in a gas turbine blade." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329915.
Full textVigueras, Zuniga Marco Osvaldo. "Analysis of gas turbine compressor fouling and washing on line." Thesis, Cranfield University, 2007. http://hdl.handle.net/1826/2448.
Full textFsadni, Andrew M. "The fundamentals of two-phase flow in wet domestic central heating systems." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/6953.
Full textBurton, Michael S. M. (Michael J. ). Massachusetts Institute of Technology. "Solar-electric and gas powered, long-endurance UAV sizing via geometric programming." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112414.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 83-85).
Fueled by telecommunication needs and opportunities, there has been a recent push to develop aircraft that can provide long-endurance (days to weeks) persistent aerial coverage. These aircraft present a complicated systems engineering problem because of the multifaceted interaction between aerodynamics, structures, environmental effects, and engine, battery, and other component performance. Using geometric programming, models capturing the interaction between disciplines are used to analyze the feasible limits of solar-electric and gas powered, long-endurance aircraft in seconds to a level of detail and speed not previously achieved in initial aircraft sizing and design. The results show that long-endurance, gas powered aircraft are generally more robust to higher wind speeds than solar-powered aircraft, but are limited in their endurance by the amount of fuel that they can carry. While solar-electric powered aircraft can theoretically fly for months, they are operationally limited by reduced solar flux during the winter and wind speeds at higher latitudes. A detailed trade study between gas-powered and solar-powered aircraft is performed to discover which architecture is best suited to meet a given set of requirements, and what is the optimum size and endurance of that platform.
by Michael Burton.
S.M.