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Zhodnocení napojení JEDU na horkovodní síť města Brna / Case study on utilizing of heat from the nuclear power plant Dukovany in the district heating systemKozel, David January 2010 (has links)
In this thesis, I was solved assessment of nuclear power plant Dukovany, conection to the hot water network to city Brno. For determine the size needful enforcement was necessary to establish the heat balance of needs of the city of Brno and the size of the heat supply options. After that it was possible to determine the dimensions of pipes and optimize his routes of due to the current state of land along the route of thermal power supply. Power supply parameters were chosen with regard to the possibilities of technology used for transmission of the media and the status quo for distribution of the city Brno. After pushing the power supply ahead of the city Brno into the pumping station Bosonohy, and second part of the solution was the connection to the backbone wiring SCZT heat to individual customers. The last point was elaborated design management system of heat from nuclear power plant and urban local based resources on current management of heat supply system using consumption diagrams SCZT.
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Studie av termiskt klimat : I ett kontorslandskap med stora fönster / Study of thermal climate : In an office landscape with large windowsStåhlman, Isak January 2017 (has links)
I genomsnitt tillbringar människan större delen av sitt liv inomhus och därför är det viktigt med ett bra inomhusklimat. I Swecos kontor i Uppsala finns det ett missnöje med det termiska klimatet vilket är en del av inomhusklimatet. Kontoret är utformat som ett kontorslandskap med stora fönster. Syftet med detta arbete är att få mer kunskap om termiskt klimat vid stora fönster och glasfasader. Målet är att identifiera orsakerna till missnöjet med det termiska klimatet och att ge kunskapsåterkoppling till kommande projekteringar. I arbetet görs en litteraturstudie för att skapa en teoretisk referensram. Efter det så görs en förstudie för att förstå nuläget och få en bild av missnöjet. Beräkningar, simuleringar och mätningar görs för att utesluta och identifiera orsaker till missnöjet. I arbetet gjordes effektberäkningar på värmebalans vilket visade att effektbehovet var tillgodosett i de två zonerna som studerats. Klimatsimuleringar i de två zonerna utfördes i simuleringsprogrammet IDA Klimat och Energi, där resultaten från simuleringarna höll sig inom kravgränser. Något som däremot inte kan simuleras är lufthastigheter. Mätningar på lufttemperatur och yttemperatur utfördes i de två zonerna. I den ena zonen stämde inte mätvärden överens med börvärdet från rumsenheten. I den andra zonen uppskattades fönsterglasets värmegenomgångskoefficient till 1,3 W/(m2K) vilket kan jämföras med den projekterade värmegenomgångskoefficienten för hela fönstret som är 0,8 W/(m2K). Vid beräkning av lufthastighet från kallras i vistelsezonen användes formler från en studie gjord av Heiselberg. Vid en dimensionerande vinterutetemperatur på -19 °C, en innetemperatur på 22 °C och en fönsterhöjd på 2,4 meter låg lufthastigheten på kravgränsen 0,15 m/s med en värmegenomgångskoefficient på 0,8 W/(m2K) och över kravgränsen med en värmegenomgångskoefficient på 1,3 W/(m2K). Slutligen visade resultaten från arbetet att i den första zonen identifierades orsaken till missnöjet med att styrningen av de klimatstyrande installationerna inte fungerade som tänkt. I den andra zonen identifierades orsaken till missnöjet med att ingen värmekälla användes under fönster för att motverka kallras. Värmekälla under fönster skulle behövas enligt beräkningar från arbetet och enligt litteraturstudien som gjordes i arbetet. Med material från arbetet skapas ett dokument om kallras som kunskapsåterföring till Sweco. Nyckelord: Termiskt klimat, Klimatsimulering, Värmebalans, Kallras, Stora fönster / On average, humans spend most of their life indoors and that is why it is so important to have a good indoor climate. At Sweco ́s office in Uppsala there is a dissatisfaction with the thermal climate, which is a part of the indoor climate. The office is designed with an office landscapes and large windows. The purpose with this project is to get more knowledge about thermal climate within large windows and glass facades. The goal with this project is to identify the reasons for the dissatisfaction with thermal climate and to provide knowledge feedback to the company’s future projects. In the project, a literature study is being conducted to create a theoretical framework. After that, a preliminary study is made to understand the current situation and to get a picture of the dissatisfaction. Calculations, simulations and measurements are made to exclude and identify reasons for the dissatisfaction. In the project calculations on heat balances were made and the calculations showed the power requirement was met in the two zones studied. Climatic simulations in the two zones were conducted in the simulation software IDA Indoor Climate and Energy, where the results from the simulations were within limits. However, something that cannot be simulated is air velocities. Measurements of air temperature and surface temperature were performed in the two zones. In one zone, the measured values did not match the set point from the room unit. In the other, the window glass heat transfer coefficient was estimated to be 1,3 W/(m^2)K, which is comparable to the projected heat transfer value for the entire window, which is 0,8 W/(m^2)K. When calculating air velocity from cold downdraught in the residential zone, Heiselberg formulas were used. At an outdoor design temperature for winter of -19 degrees Celsius, an indoor temperature of 22 degrees Celsius and a window height of 2,4 meters, the air velocity result at the 0,15 m/s limit when the heat transfer value was 0,8 W/(m^2)K and resulting in a value above the limit when the heat transfer value was 1,3 W/(m^2)K. Finally, the results showed that in the first zone, the reason for the dissatisfaction was identified with the fact that the control of the climate control installations did not work as intended. In the second zone, the reason for the dissatisfaction was identified that no heat source was used under windows to prevent cold downdraught. Heat source under windows would be needed according to calculations from work and according to the literature study that was done in this work. With material from the work, a document is created about cold downdraught as knowledge feedback to Sweco. Keywords: Thermal climate, Climate simulation, Heat balance, Cold downdraught, Cold downdraft, Large windows
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Kondenzační parní turbína / Condensing Steam Turbine C55Borýsek, Václav January 2020 (has links)
This diploma thesis deals with the design of a steam condensing turbine for intake steam of pressure 125 bar, temperature 540 °C and maximal intake of steam into the turbine 130 t/h. A thermal scheme is designed, including low-pressure and high-pressure regeneration, an air condenser, a feed tank and a boiler. Afterwards a thermodynamic design of a condensing turbine is made with an A-wheel type regulating stage and a stage part with reaction blades. The design of the blades is strength-tested. Then is made the design of the compensating piston and the sealing system. In the end the characteristics of the turbine for non-design steam flows is plotted. The designed turbine has a power of 34644 kW, has a thermodynamic efficiency of 85.1% and a reheat factor of 1.046.
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Bypassový systém parních turbín / Bypass steam turbine systemMolák, Filip January 2021 (has links)
The master’s thesis deals with the bypass system of steam turbine, especially about its heating during normal operation and cold start up. At the beginning of work, a preliminary thermodynamic calculation of condensing steam turbine with two uncontrolled extractions is made. This is followed by theoretical description and design of bypass system and design of heating during normal operation and cold start-up. The main goal of thesis is optimalization of heating, when the heating branch is connected back to turbine supply line. In the end, all options of heating are compared in terms of power output.
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Retrofit parní turbiny 250 MW na biomasu / Biomass Retrofit 250 MW Steam TurbineNovák, Martin January 2013 (has links)
There is a description of modernisation steam condensing turbine in this Master´s thesis. Electric output is decreased from 250 MW to 160 MW. This thesis is divided into two parts, there is a calculation of heat balance in first part and a calculation of blading in second part. Detail drawing and heat balance are the most important results of this Master´s thesis.
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Kondenzační parní turbína / Condensing Steam TurbineŠrůtek, Petr January 2016 (has links)
The theme of master's thesis is the design of condensing steam turbine with three unregulated steam outputs. The steam parameters in individual outputs are dealt with in heat balance circulation. This chapter is followed by thermodynamic and strength calculations, including the calculation of the turbine gland steam and design of drainage. Structural design of the turbine is also included in this thesis.
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Study of The Effect of Convective Heat Transfer on Cooling of Overhead Line Conductors Based on Wind Tunnel Experimental Results / Studie av Effekten av Konvektiv Värmeöverföring vid Kylning av Ledningsledare Baserat på Experimentellt Resultat från VindtunnelnNaim, Wadih January 2018 (has links)
It is important to keep an overhead power line within rated operating conditions. Thus,an accurate prediction of the conductor's thermal and electrical behavior leads to an increasein reliability and eciency. Under DLR operation, the current rating is adjustedbased on ambient weather and solar conditions to allow for dynamic line loading. Therating adjustment takes into account the cooling mechanisms acting on the conductor. Inthis thesis, cooling by means of convective heat transfer is studied based on wind tunnelexperimental measurements of three dierent conductor samples. Convection contributesto most of the cooling; however, it is aected by wind speed and direction. Two angle ofattacks were studied (40 and 90), where perpendicular ow was found to result in bettercooling. The location of boundary layer separation highly aects the surface distribution ofcooling, which is non-uniform. Oblique wind ow results in reduction in overall cooling dueto earlier boundary layer separation. Finally, the surface average convective heat transfercoecient correlates non-linearly with the Reynolds number, where higher wind speeds andlarger conductor diameters can lead to signicant improvements in cooling while keepingrelatively low current densities. The existing standards of IEEE and CIGRE were found tooverestimate the eect of convective cooling for the specic experimental cases. / Det är viktigt att hålla en kraftöverföringsledning inom nominella driftsförhållanden.Således leder en korrekt förutsägelse av ledarens termiska och elektriska beteende till en ökad tillförlitlighet och effektivitet. Under DLR-drift justeras nuvärdet baserat på omgivande väder och solförhållanden för att möjliggöra dynamisk belastning. Klassificeringsjusteringen tar hänsyn till de kylmekanismer som verkar på ledaren. I denna avhandling studeras kylning med hjälp av konvektiv värmeöverföring baserat på provning av vindtunnel av tre olika ledartyper. Konvektion bidrar till det mesta av kylningen. Det påverkas dock av vindhastighet och riktning. Två angreppsvinkelar studerades (40◦ och 90◦), där vinkelrätt flöde befanns resultera i bättre kylning. Placeringen av ytskiktseparationen har stor inverkan på ytfördelningen av kylning, vilken är ojämn. Skrå vindflöde resulterar i minskning av den totala kylningen på grund av tidigare separering av gränsskiktet. Slutligen korrelerar den ytvärdesöverföringskoefficienten för ytvärdet icke-linjärt med Reynolds-talet, där högre vindhastigheter och större ledardiametrar kan leda till signifikanta förbättringar i kylning samtidigt som relativt låga strömtäthet hålls. De befintliga standarderna för IEEE och CIGRE visade sig överskatta effekten av konvektiv kylning för de specifika experimentellafallen.
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Wasseraufnahme und artspezifische hydraulische Eigenschaften der Feinwurzeln von Buche, Eiche und Fichte: In situ-Messungen an Altbäumen / Water uptake and species-specific hydraulic properties of beech, oak and spruce fine roots: In situ measurements on old-growth treesConers, Heinz 30 October 2001 (has links)
No description available.
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Etude des couplages thermomécaniques dans des fils super-élastiques nanostructurés nickel-titane / Study of thermomechanical couplings in nanostructured superelastic nickel-titanium wiresMartinni Ramos de Oliveira, Henrique 05 October 2018 (has links)
Cette thèse est une étude expérimentale du comportement thermo-mécanique superélastique d'un fil nanocristallin Ti-50.9Ni at.% Ni en alliage à mémoire de forme (SMA) (diamètre 0.5 mm), après subir un cold work (CW). Les AMF sont capables d'induire des changements de température importants lorsqu'ils sont chargés mécaniquement. Ce phénomène est dû à un important couplage thermomécanique présent dans cette transformation de phase solide entre les phases Austénite (A) et Martensite (M).La chaleur latente par unité de masse (ΔH) tout au long de la transformation de phase est l'énergie responsable de cette variation de température. La détermination de ΔH est généralement effectuée par calorimétrie à balayage différentiel (DSC). Cependant, pour les SMA nanocristallins, les résultats DSC obtenus ne sont pas concluants sur la détermination de cette propriété.Dans ce travail, une méthode utilisant la corrélation d'image numérique (DIC) et les mesures de champ thermique (TFM) a été utilisée pour analyser les couplages thermomécaniques lors d'une transformation de phase induite par contrainte. Des champs cinématiques et thermiques ont été acquis lors d'essais de traction superélastiques réalisés sur des fils CW NiTi soumis à différentes températures de traitements thermiques (TTT) allant de 523 à 598 K pendant 30 min. Un tel traitement thermique à basse température favorise une boucle totalement superélastique sans plateau de contrainte et sans déformation de type Lüders. En supposant un modèle thermique uniforme, les sources de chaleur impliquées lors du chargement cyclique ont été estimées. Cette puissance thermique par unité de masse a été comparée à la puissance mécanique et intégrée au fil du temps pour obtenir l'équilibre énergétique. De plus, grâce à une analyse thermodynamique basée sur l'énergie libre de Gibbs, les valeurs de ΔH, ainsi que la fraction de martensite, ont été estimées au cours des transformations de phase A-M directe et inverse M-A. L'analyse des résultats a conduit aux conclusions suivantes: (1) Les puissances et énergies thermiques et mécaniques présentaient une dépendance significative vis-à-vis du TTT. (2) Malgré l'effet important des valeurs du TTT sur les réponses mécaniques et thermiques, les ΔH obtenues étaient très proches pour tous les TTT et dans la même gamme de valeurs fondée dans la littérature pour un alliage Ti-50.9Ni at.% Ni entièrement recuit testé par technique DSC. (3) Pour une deformation donnée, la fraction de martensite augmente avec l'augmentation de TTT. (4) Pour une contrainte imposée de 4,5%, la fraction de martensite augmente de 30% à 40% en augmentant le TTT de 523K à 598K. / This PhD thesis is an experimental study of the thermomechanical superelastic behaviour of a Ti-50.9Ni at.% Ni Shape Memory Alloy (SMA) nanocrystalline thin wire (diameter 0.5 mm), in a Cold Worked (CW) state. SMAs are capable of inducing important temperature change when they are mechanically loaded. This phenomenon is due to an important thermomechanical coupling present in this solid phase transformation between Austenite (A) and Martensite (M) phases. The latent heat per unit of mass (∆H) throughout the phase transformation is the energy responsible of this temperature variation. The determination of ∆H is generally performed by differential scanning calorimetry (DSC). However, for nanocrystalline SMAs, the obtained DSC results are non conclusive on the determination of this property.In this work, a method using digital image correlation (DIC) and thermal field measurements (TFM) was used to analyse the thermomechanical couplings during a stress induced phase transformation (SIPT). Kinematics and thermal full fields were acquired during superelastic tensile tests performed on the CW NiTi wire submitted to different heat treatments temperatures (HTT) ranging from 523 to 598 K during 30 min. Such a heat treatment at low temperature promoted a fully superelastic loop without stress plateau and no Lüders-like deformation. Assuming a uniform thermal model, the heat sources involved during the cyclic loading were estimated. This thermal power per unit of mass was compared to the mechanical one and integrated over the time to get energy balance. Further, through a thermodynamic analysis based on the Gibbs free energy, the values of ∆H, as well as the martensite fraction, were estimated during the forward A-M and reverse M-A phase transformations. The analysis of the results led to the following conclusions: (1) Thermal and mechanical powers and energies presented a significant dependence on the HTT. (2) Despite the strong effect of the values of the HTT on mechanical and thermal responses, the obtained ∆H were very close for all HTT and in the same range of values founded in the literature for a fully annealed Ti-50.9Ni at.% Ni alloy tested via DSC technique. (3) For a given strain, martensite fraction increases with increasing HTT. (4) For an imposed strain of 4.5%, the martensite fraction increases from 30% to 40% when increasing HTT from 523K to 598K.
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Kinematics and Heat Budget of the Leeuwin CurrentDomingues, Catia Motta, Catia.Domingues@csiro.au January 2006 (has links)
This study investigates the upper ocean circulation along the west Australian coast, based
on recent observations (WOCE ICM6, 1994/96) and numerical output from the 1/6 degree Parallel Ocean
Program model (POP11B 1993/97). Particularly, we identify the source regions of the Leeuwin
Current, quantify its mean and seasonal variability in terms of volume, heat and salt transports,
and examine its heat balance (cooling mechanism). This also leads to further understanding of the
regional circulation associated with the Leeuwin Undercurrent, the Eastern Gyral Current and the
southeast Indian Subtropical Gyre.
The tropical and subtropical sources of the Leeuwin Current are understood from an
online numerical particle tracking. Some of the new findings are the Tropical Indian Ocean source
of the Leeuwin Current (in addition to the Indonesian Throughflow/Pacific); the Eastern Gyral
Current as a recirculation of the South Equatorial Current; the subtropical source of the Leeuwin
Current fed by relatively narrow subsurface-intensified eastward jets in the Subtropical Gyre, which
are also a major source for the Subtropical Water (salinity maximum) as observed in the Leeuwin
Undercurrent along the ICM6 section at 22 degrees S.
The ICM6 current meter array reveals a rich vertical current structure near North West
Cape (22 degrees S). The coastal part of the Leeuwin Current has dominant synoptic variability and
occasionally contains large spikes in its transport time series arising from the passage of tropical
cyclones. On the mean, it is weaker and shallower compared to further downstream, and it only
transports Tropical Water, of a variable content. The Leeuwin Undercurrent carries Subtropical
Water, South Indian Central Water and Antarctic Intermediate Water equatorward between
150/250 to 500/750 m. There is a poleward flow just below the undercurrent which advects a
mixed Intermediate Water, partially associated with outflows from the Red Sea and Persian Gulf.
Narrow bottom-intensified currents are also observed.
The 5-year mean model Leeuwin Current is a year-round poleward flow between 22 degrees S and
34 degrees S. It progressively deepens, from 150 to 300 m depth. Latitudinal variations in its volume
transport are a response to lateral inflows/outflows. It has double the transport at 34 degrees S (-2.2 Sv)
compared to at 22 degrees S (-1.2 Sv). These model estimates, however, may underestimate the transport
of the Leeuwin Current by 50%. Along its path, the current becomes cooler (6 degrees C), saltier (0.6 psu)
and denser (2 kg m -3). At seasonal scales, a stronger poleward flow in May-June advects the
warmest and freshest waters along the west Australian coast. This advection is apparently spun up
by the arrival of a poleward Kelvin wave in April, and reinforced by a minimum in the equatorward
wind stress during July.
In the model heat balance, the Leeuwin Current is significantly cooled by the eddy heat
flux divergence (4 degrees C out of 6 degrees C), associated with mechanisms operating at submonthly time scales.
However, exactly which mechanisms it is not yet clear. Air-sea fluxes only account for ~30% of the
cooling and seasonal rectification is negligible. The eddy heat divergence, originating over a narrow
region along the outer edge of the Leeuwin Current, is responsible for a considerable warming of a
vast area of the adjacent ocean interior, which is then associated with strong heat losses to the
atmosphere. The model westward eddy heat flux estimates are considerably larger than those
associated with long lived warm core eddies detaching from the Leeuwin Current and moving
offshore. This suggests that these mesoscale features are not the main mechanism responsible for
the cooling of the Leeuwin Current. We suspect instead that short lived warm core eddies might
play an important role.
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