The diploma thesis concentrates on a project of backpreassure steam turbine. These topics are analyzed in more detail: design of balance schema, thermodynamic calculation, loss coefficient and its effect on the loss. Technical solutions are designed according to given details of a steam and chosen conditions of use.

The once through steam generator (OTSG) is a single pass counter flow heat exchanger in which primary pressurized water from the core is circulated. Main Feedwater is injected in an annular gap on the outer periphery of the steam generator shroud such that it aspirates steam to preheat the feedwater to saturation temperature. An important component of the OTSG and enhanced once through steam generator (EOTSG) is the auxiliary feedwater system (AFW), which is used during accident/transient scenarios to remove residual heat by injecting water through jets along the outer periphery of the heat exchanger core directly on to the tubes at the top of the OTSG. The intention is for the injected water, which is subcooled, to spread into the tube nest and wet as many tubes as possible. In this project, the main objectives were to use first principles Computational Fluid Dynamics to predict the number of wetted tubes versus flow rate in the EOTSG at the AFW injection location above the top tube support plate. To perform the fluid analysis, the losses in the bypass leakage flow and broached hole leakage flow were first quantified and then used to model a 1/8th sector of the EOTSG. Using user defined functions (UDF), the loss coefficients of the leakage flows were implemented on the 1/8th sector of the EOTSG computational model to provide boundary conditions at the bypass flow and leakage flow locations With this method, the number of tubes wetted in the sector of EOTSG for various AFW flow rates was found. Results showed that the number of wetted tubes was in very close agreement to that predicted by experimental-analytical methods by the sponsor, AREVA. With the maximum flow rate of 65 l/s a total of 318 tubes were wetted and the percentage of tubes wetted with broached holes was 8.7%. The analysis on the bypass leakage flow showed that the loss coefficients was a function of the mass flow rate or the flow Reynolds number through the gap and it increased as the Reynolds number increased from 300 to 1600. The experimental and computational loss coefficients agree to within 15% of each other. In contrast, the constant loss coefficient of 1.3 used by AREVA was much higher than that obtained in this study, particularly in the low Reynolds number range. As the Reynolds number approached 3000, the loss coefficients from this study approached the value of 1.3. This value of the loss coefficient was implemented for the bypass flow leakage in the 1/8th sector of the EOTSG model. The analysis on the broached hole leakage flow was performed using a single hole, five holes, and one, two, four and eight rows of broached holes in order to characterize the loss coefficients. The one hole and five hole computational models were validated with experiments. The computational models showed the presence of voids in the leakage flow through the tube support plate (TSP), which were not observed (visually) in the experiments. The characterization of the broached hole leakage in the one, two and four rows showed that the loss coefficient of the control broached hole increased as the number of rows increased. These results indicated that for the same height of water on the TSP, the resistance to leakage flow increased as the number of tubes increased. They also indicated that leakage flow through the broached holes was not solely a function of the height of water above the TSP but also the surrounding geometrical topology and the flow characteristics. However, the analysis done for eight rows showed that the loss coefficient became constant after a certain number of rows as the loss coefficient differed by only 5% from the results of the four rows. From these results it was determined that the loss coefficient asymptotes to an estimated value of 4.0 which was implemented in the broached hole leakage flow in the 1/8th sector of the EOTSG. Computational models of the 1/8th sector of the EOTSG were implemented with the respective loss coefficients for the bypass and leakage flows. Results showed that as the AFW flow rate increased, the percentage wetted tubes increased. The data matched closely with AREVA's experimental-analytical model for flow rates of 14.5 l/s and higher. It was also deduced that complete wetting of the tubes is not possible at the maximum AFW flow rate of 65 l/s. / Master of Science

Made available in DSpace on 2017-07-10T15:14:45Z (GMT). No. of bitstreams: 1 Mauricio Medeiros.pdf: 2573107 bytes, checksum: 1e5a17966417b43d576f37b4837c682b (MD5) Previous issue date: 2012-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work was developed at the State University of West of Paraná UNIOESTE, campus de Cascavel and was aimed at developing a computer program to simulate and scale, optimally, a system of solar water heating. To determine the efficiency parameters of the system were installed three solar collectors of 1.05 m2 each, brand Pro Sol, coupled to a thermal reservoir of 200 liters, containing electrical resistances auxiliary 2000 W. The system works by using thermosyphon, and was installed in a metal bracket fixed to the ground, oriented to the north at an angle of 35 degrees from the horizontal. We collected hourly data of solar radiation and water temperatures, and evaluated two scenarios. In the first scenario, it was considered system utilization auxiliary heating controlled by a thermostat, which linked and hang up the electrical resistances as the temperature of water in boiler oscillated around of temperature of consumption (40 º C). In the second scenario, it was considered the system to power auxiliary heating only in timetables of water consumption, when the water temperature in boiler was lower than the temperature of consumption. Coefficients were calculated heat loss in the solar collector and storage tank, the heat removal factor of solar collector and the overall efficiency of the heating system installed. These calculated parameters and other data collected were used in software developed for simulation and design in order to satisfactorily meet the needs of hot water consumption, and minimize the total installation costs and energy consumption. Finally, these system costs solar heating were compared to costs of an electric shower conventional. The results obtained were as follows: coefficient of heat loss in the solar collector (5,45 Wm-2ºC-1), coefficient of heat loss in the thermal reservoir (5,34 Wm-2ºC-1), removal factor heat of the solar collector (0.78) and overall system efficiency (31%). The times of return on capital invested in the solar heating system (compared to a conventional electric shower), for the two scenarios of use, were, respectively, 11.45 years and 7.81 years. / Este trabalho foi desenvolvido na Universidade Estadual do Oeste do Paraná UNIOESTE, campus de Cascavel, e teve por objetivo principal o desenvolvimento de um programa computacional para simular e dimensionar, de forma otimizada, um sistema de aquecimento solar de água. Para determinar os parâmetros de eficiência do sistema, foram instalados três coletores solares de 1,05 m2 cada, da marca Pro Sol, acoplados a um reservatório térmico de 200 litros, contendo resistências elétricas auxiliares de 2000 W. O sistema utilizado funciona por termossifão, e foi instalado em um suporte metálico fixado ao solo, com orientação para o norte, num ângulo de 35º em relação à horizontal. Foram coletados dados horários de radiação solar e temperaturas da água, e avaliados dois cenários. No primeiro cenário, considerou-se a utilização do sistema de aquecimento auxiliar controlado por um termostato, que ligava e desligava as resistências elétricas conforme a temperatura da água no boiler oscilava em torno da temperatura de consumo (40ºC). No segundo cenário, considerou-se o acionamento do sistema de aquecimento auxiliar somente nos horários de consumo de água, quando a temperatura da água no boiler estivesse menor que a temperatura de consumo. Foram calculados os coeficientes de perda de calor no coletor solar e no reservatório térmico, o fator de remoção de calor no coletor solar e a eficiência global do sistema de aquecimento instalado. Esses parâmetros calculados, e os demais dados coletados, foram utilizados no software desenvolvido para simulação e dimensionamento, de maneira a atender satisfatoriamente às necessidades de consumo de água quente, e minimizar os custos totais de instalação e consumo de energia elétrica. Por fim, esses custos do sistema de aquecimento solar foram comparados aos custos de um chuveiro elétrico convencional. Os resultados obtidos foram os seguintes: coeficiente de perda de calor no coletor solar (5,45 Wm-2ºC-1), coeficiente de perda de calor no reservatório térmico (5,34 Wm-2ºC-1), fator de emoção de calor do coletor solar (0,78) e eficiência global do sistema (31%). Os tempos de retorno do capital investido no sistema de aquecimento solar (em comparação a um chuveiro elétrico convencional), para os dois cenários de utilização, foram de, respectivamente, 11,38 anos e 5,73 anos.

<p>Predložen je i testiran model za energetsko vrednovanje kogenerativnih postrojenja pri čemu se proračun koeficijenta gubitka električne snage obavlja pomoću postupka koji je posebno naveden i predložen.<br />Sam model može i treba da predstavlja snažan alat prilikom kreiranja energetske politike, u delu koji se odnosi na kogeneraciju, s obzirom na to da pruža mogućnost jasnog energetskog vrednovanja postrojenja u smislu efikasnosti i uštede primarne energije kao i definisanja koji deo i koliko kogeneracija treba da bude stimulisana, odnosno potencijalno zastupljena u okviru nekog energetskog sistema.<br />Predloženi model je testiran na složenom kogenerativnom postrojenju snage 150 MW.</p> / <p>A model for energy evaluation of a cogeneration plant is proposed<br />and tested with the calculation of electric power loss done by means<br />of a procedure which is particularly specified and proposed.<br />The model itself can and should be used as a powerful tool for the<br />creation of energy policies in the part regarding cogeneration since it<br />gives opportunities for a clear energy evaluation of a plant in terms of<br />efficiency and primary energy saving, as well as for defining which<br />part and to what extent cogeneration should be stimulated, that is,<br />potentially represented within a specified energy system.<br />The proposed model has been tested on a cogeneration plant with<br />the capacity of 150 MW.</p>

Pressure drop across miniature-scale flow disturbances, including abrupt flow area changes, is an important source of error and confusion in the literature. Such pressure drops are frequently encountered in experiments, where they are often estimated using methods and correlations that have been developed based on experimental data obtained in conventional systems. However, physical arguments as well as the relatively few available experimental observations indicate that such pressure drops in microchannel systems are likely to be different than what is known about similar phenomena in conventional flow systems. Experimental data dealing with pressure drop associated with two-phase flow across abrupt flow area changes in microchannels are scarce, however, and the available data are insufficient for the development of reliable predictive methods. In this investigation, experiments were conducted using a test section consisting of two capillaries, one with 0.84 mm, and the other with 1.6 mm inner diameters. A multitude of pressure transducer ports were installed along the two capillaries, and allowed for the measurement of the pressure gradients over the entire test section. The test section allowed for the measurement of frictional pressure gradients in the two straight channels, as well as pressure drops caused by the flow area expansion and contraction depending on the flow direction, for single-phase as well as two-phase flows. These measurements were performed over a wide range of parameters, using air as the gaseous phase, and room-temperature water as the liquid phase. The single-phase flow data were compared with existing conventional correlations, and with predictions of CFD simulations using the Fluent computer code.

The aim of this thesis is to design an air conditioning system of a flat unit in two variants of piping. The piping system of the first floor is installed into the floor in one variant, in the other it is in the ceiling. Data received from measurements within the experiment have been used for the design. The result of the measurement are minor loss coefficient implemented for bending pipes and pressure losses caused by rubbing. These values are used for dimensioning piping variants. Both types of piping are described in the theoretical part and the method of how the experiment had been processed.

Several climate and energy goals have been set in the European Union, one of them being to increase energy efficiency. In Sweden, a large potential for increased energy efficiency lies in the residential and service sectors, which account for about 40% of total energy use. A large share of buildings in Sweden were built in the Million Homes Program in the 1960s and ’70s. These buildings are now in need of renovation, which enables renovation with the ambition of reducing energy use.  In this thesis, the purpose is to develop an energy signature method, a bottom-up statistical method. This method has been validated using a building energy simulation software called IDA ICE, for two kinds of multifamily buildings from the Million Homes Program. The energy signature method has then been applied to a district located in Gävle, Sweden, containing more than 90 multifamily buildings with similar construction. In addition to characterizing current thermal performance of the buildings, the energy signature method is further developed so that potential for energy renovation of the district can be simulated. Simulated energy renovation is developed to comply with building energy use requirements, according to the most recent Swedish building regulations.  Both on building and district level, sensitivity analysis is performed. In both cases the energy signature method is insensitive to changes in internal heat gains and indoor temperature. To investigate the effects of simulated renovation on a local district heating system, results are visualized in a duration diagram, where energy use reduction in different load periods is displayed. Thus, it is demonstrated how the energy signature method can be used as a rapid way of simulating energy renovation on district level and with readily available data. / EU har beslutat om flera klimat- och energimål, bland annat att energi ska användas mer effektivt. I Sverige finns en stor potential för ökad energieffektivitet i bostads- och servicesektorn, som står för cirka 40 % av den totala energianvändningen. En stor av del Sveriges byggnadsbestånd består av miljonprogramsbyggnader från 1960- och 1970-talen. Dessa byggnader är i behov av renovering, vilket möjliggör ytterligare renovering med syfte att sänka energianvändningen. Syftet med denna studie är att utveckla en energisignaturmetod, en ”bottom-up” statistisk metod. Metoden har validerats med byggnadsenergisimuleringsprogrammet, IDA ICE, för två typer av flerbostadshus från miljonprogrammet. Energisignaturmetoden har sedan applicerats på ett distrikt i Gävle som innehåller fler än 90 flerbostadshus med liknande konstruktion. Förutom att karakterisera byggnadernas nuvarande termiska prestanda, vidareutvecklas energisignaturmetoden så att även energirenovering kan simuleras. Denna metod utvecklas för att uppfylla Boverkets krav på byggnaders energianvändning, enligt gällande svenska byggnadsreglerna.  Känslighetsanalys utförs både på byggnads- och distriktsnivå. I båda fallen visar sig energisignaturmetoden vara okänslig för förändringar i intern värmegenerering och inomhustemperatur. Effekterna av den simulerade renoveringen presenteras i ett varaktighetsdiagram, som visar de möjliga effekterna på ett lokalt fjärrvärmesystem. På detta sätt demonstreras hur energisignaturmetoden kan användas för att snabbt simulera energirenovering på distriktsnivå och med lättillgänglig data.

In this Master thesis are mentioned the most used constructions of non-return valves. Further consist of operation principles, fields of application, properties and diffi-culties connected to non-return valves. Motion plug of check valve in liquid is described based on CFD Software simulation.

The master thesis is focused on rating of buildings with almost zero energy consumption. Theoretical part summarizes general requirements on buildings with almost zero energy consumption. It also discusses other categories of buildings on terms of energy demand and influences and factors affecting the energy performance of buildings. The calculating part comparing three different construction systems of designed family house by means of energy demand with energy assessment and energy performance certificate of buildings.

This thesis deals with the processing of an energy audit of the selected building for daily education. The target of this thesis is an evaluation of the current situation of the building, it means the evaluation of the thermal-technical qualities and energy consuption. For the initial state new measures will be suggested to reduce the energy consuption. One of the measures will be a proposal for an alternative way of supplying of the thermal energy, using the thermal pump. These suggested saving measures will be evaluated, including basic economic analysis.