Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-15T13:18:20Z No. of bitstreams: 1 Fábio Ricardo de Oliveira de Souza.pdf: 10103280 bytes, checksum: 4e2fd0c8307348f7e9098749cafe8b73 (MD5) / Made available in DSpace on 2015-07-15T13:18:20Z (GMT). No. of bitstreams: 1 Fábio Ricardo de Oliveira de Souza.pdf: 10103280 bytes, checksum: 4e2fd0c8307348f7e9098749cafe8b73 (MD5) Previous issue date: 2013-01-31 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / Este trabalho apresenta um estudo numérico sobre características de escoamento e transferência de calor em tubo evacuado. A abordagem numérica foi realizada com o software comercial ANSYS-CFX. O modelo numérico adotado é tridimensional e é composto pelas equações da conservação da massa, quantidade de movimento e energia. A malha computacional é do tipo hexaédrica, com refinamento nas regiões de maiores gradientes térmicos e fluidodinâmicos. O modelo implementado foi validado com resultados numéricos da literatura e um estudo de caso foi realizado, considerando variações do ângulo de inclinação do tubo, da variação da taxa de transferência de calor para o tubo e da variação da temperatura da água proveniente do reservatório térmico. Também foram avaliadas duas hipóteses: uma considerando propriedades físicas da água constantes e a outra com propriedades variáveis com a temperatura. Comparações são apresentadas para campos de velocidade e temperatura, vazão mássica e números de Nusselt e de Reynolds. O comparativo entre os resultados obtidos com a hipótese de propriedades constantes, com aqueles obtidos com propriedades variáveis mostra diferenças significativas entre eles, apontando a importância do uso de propriedades variáveis neste tipo de simulação numérica. Os resultados dos estudos paramétricos indicam que o incremento da vazão mássica e da temperatura média de saída do fluido é diretamente proporcional ao incremento do ângulo de inclinação, da taxa de transferência de calor e da temperatura do reservatório térmico. / This work presents a numerical study on characteristics of flow and heat transfer in an evacuated tube. The numerical approach was performed with the commercial software ANSYS-CFX. The numerical model adopted is three-dimensional and consists of the mass, momentum and energy equations. The computational mesh is hexaedrical, with refinement in regions of higher thermal and fluid gradients. The implemented model was validated with numerical results of literature and a case study was conducted considering inclination angle, rate of heat transfer and water temperature from the thermal reservoir. Also were evaluated two hypotheses: one considering constant physical properties of water and the other with properties varying with temperature. Comparisons are presented for velocity and temperature fields, mass flow and Nusselt and Reynolds numbers. The comparison between the results obtained with the hypothesis of constant properties, with those obtained with variable properties, shows significant differences between them, pointing out the importance of using variable properties in this type of numerical simulation. The results of the parametric studies indicate that the increment of the mass flow and average temperature of the fluid is directly proportional to the inclination angle, the rate of heat transfer and the temperature of the thermal reservoir.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-20T14:17:58Z No. of bitstreams: 1 Ronaldo Bueno de Souza.pdf: 1999281 bytes, checksum: 5dd2b3645a9e4750a12f291e30ba6d41 (MD5) / Made available in DSpace on 2015-07-20T14:17:58Z (GMT). No. of bitstreams: 1 Ronaldo Bueno de Souza.pdf: 1999281 bytes, checksum: 5dd2b3645a9e4750a12f291e30ba6d41 (MD5) Previous issue date: 2015-04-07 / CYTED - Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo / Este trabalho apresenta o estudo de um sistema de refrigeração por absorção assistido por energia solar térmica com intuito de ser empregado no arrefecimento de uma pousada de ecoturismo localizada em um local remoto, desprovida de conexão à rede elétrica. Para o estudo do sistema proposto foi utilizado o software de simulações TRNSYS, onde em uma etapa inicial do trabalho foi realizada a comparação dos resultados do software com os resultados dos modelos matemáticos dos componentes do sistema de refrigeração. Foi desenvolvido um modelo computacional, para realização de simulações horárias que permitiu a simulação de três configurações de sistemas de refrigeração por absorção, podendo assim determinar a influência dos componentes e parâmetros utilizados no sistema no uso da energia auxiliar e no atendimento da carga térmica. O primeiro modelo é constituído por um sistema onde a água aquecida pelo coletor solar térmico e é armazenada em um reservatório térmico, sendo a mesma utilizada para a alimentação do chiller de absorção. A água gelada produzida pelo chiller é armazenada em outro reservatório térmico onde fica disponível para o consumo. Neste modelo observa-se que com o uso de 120 m² de coletores de tubo evacuado chega-se a índices de atendimento dos consumos superiores a 87 %. O segundo modelo é similar ao primeiro, com a inclusão de um aquecedor auxiliar para a água de alimentação do chiller de absorção. Neste modelo observou-se que com o uso de 120 m² de coletores de placas planas chega-se a um consumo de energia auxiliar inferior a 195 GJ, e com o uso de 120 m² de coletores de tubo evacuado chega-se a um consumo de energia auxiliar inferior a 150 GJ. O terceiro modelo é similar ao segundo, onde foi acrescentado um sistema para utilização da água de arrefecimento do chiller de absorção, para uso no consumo de água quente para banho, nos chuveiros. Neste modelo observa-se que o aproveitamento da água de arrefecimento não afeta o consumo de energia auxiliar, se comparado com o consumo do segundo modelo. / This paper presents the study of a cooling system for absorption assisted by solar energy with a view to be used in the cooling of an ecotourism lodge located in a remote location, devoid of connection to the grid. To study the proposed system was used TRNSYS simulation software, where in an initial work step of comparing software results with the results of mathematical models of the components of the refrigeration system is performed. A computer model was developed to perform simulations slot which simulated three configurations absorption refrigeration systems and can therefore determine the influence of the components and system parameters used in the auxiliary power usage and meet the thermal load. The first model is made up of a system where the water heated by the solar thermal collector and is stored in a thermal storage tank, being the same used for feeding the absorption chiller. The chilled water produced by the chiller is stored in another thermal reservoir where it is available for consumption. In this model it is observed that with the use of 120 m² evacuated tube collectors comes to fuel consumption attendance rates of over 87 %. The second model is similar to the first, with the inclusion of an auxiliary heater to supply water from the absorption chiller. In this model we found that with the use of 120 m² of flat plate collectors comes to an auxiliary power consumption of less than 195 GJ, and with the use of 120 m² evacuated tube collectors we arrive at a consumption of auxiliary power less than 150 GJ. The third model is similar to the second, which was added to a system using the cooling water from absorption chiller for use in the consumption of hot water for baths, showers on. In this model, it is observed that the use of the cooling water does not affect the auxiliary power consumption compared with the consumption of the second model.

The thesis presents background on solar thermal energy and addresses the structural challenges associated with the deployment of concentrating solar power fields in urban areas. Two potential structural systems and urban locales of deployment are proposed and investigated to determine whether they have the potential to be a cost-effective renewable energy solution for urban areas. The structural issues explored in the thesis include flutter, the wind loading of open frame structures, performance-based design, and the design of flexibly mounted equipment on a building.

<p>One of the traditional approaches to reduce costs of solar energy is to use inexpensive reflectors to focus the light onto highly efficient solar cells. Several research projects have resulted in designs, where the excess heat is used as solar thermal energy.</p><p>Unlike a solar thermal system, which has a selective surface to reduce the radiant heat loss, a CPV/T (Concentrating PhotoVoltaic/Thermal) system uses a receiver covered with solar cells with high thermal emittance.</p><p>This project analyzes whether the heat loss from the receiver can be reduced by covering parts of the receiver surface, not already covered with solar cells, with an optically selective coating. Comparing different methods of applying such a coating and the long-term stability of low cost alternatives are also part of the objectives of this project.</p><p>To calculate the heat loss reductions of the optically selective surface coating a mathematical model was developed, which takes the thermal emittances and the solar absorptances of the different surfaces into account. Furthermore, a full-size experiment was constructed to verify the theoretical predictions.</p><p>The coating results in a heat loss reduction of approximately 20 % in such a CPV/T system and one of the companies involved in the study is already changing their design to make use of the results.</p>

<p>För ett genomsnittligt småhus i Sverige idag går ca 5000 kWh till hushållsel. Av dessa 5000 kWh går 7% till att driva diskmaskiner. Effektiviseringen av diskmaskiner har framförallt strävat efter en låg vatten- och energianvändning, en kort processtid samt en effektiv rening av disken.</p><p>Det finns dock gränser för hur effektiva diskmaskinerna kan göras med traditionell teknik. Därför har producenter under de senaste åren börjat se sig om efter mindre traditionella metoder som till exempel bruket av en värmepump för att få ned energiförbrukningen.</p><p>Syftet med det här examensarbetet har varit att ta fram systemlösningar för värmepump i diskmaskin samt att utvärdera energibesparingspotentialen i denna tillämpning.</p><p>Målet har varit att ta fram och beskriva de möjliga systemlösningar som uppstår vid en idégenerering. Att välja ut två lösningar för närmare undersökning, att bestämma en lämplig kompressoreffekt samt att beräkna energibesparingen dessa lösningar ger.</p><p>En litteraturstudie har gjorts av teknik och tillämpningar inom området, som till exempel värmeväxlaranvändning i diskmaskiner samt användandet av värmepumpar i andra vitvaror. Denna litteraturstudie följdes upp av en idégenerering, som tar hänsyn till möjliga värmekällor och –sänkor. Idégenereringen gav upphov till två systemlösningar som modellerades i MATLABs Simulink för att en lämplig kompressoreffekt och storleken på energibesparingen skulle bestämmas.</p><p>De två utvalda lösningarna ifrån idégenereringen var utomhusluftlösningen, där värme hämtas från uteluften och energilagerlösningen, där värme hämtas ur ett energilager. I båda lösningarna överförs värmen till det kalla ingående vattnet.</p><p>Energiåtgången för utomhusluftlösningen var beroende av köldmediets förångningstemperatur och modellering av lösningen visade att energiåtgången var 0,25 kWh vid en förångningstemperatur på -10°C, och 0,18 kWh vid 5°C. Vid modellering av energilagerlösningen påvisades en energiåtgång på 0,23 kWh. Slutsatsen som drogs var att kompressorn vid energilagerlösningen skall leverera en effekt på 240 W till köldmediet.</p> / <p>For an average detached house in Sweden today about 5000 kWh are used for household electricity. Of these 5000 kWh 7% are used to run dishwashers. The streamlining of dishwashers has above all strived for a lower water and energy use, a short process time along with a more efficient cleaning of the dishes.</p><p>There are however limits for how efficient the dishwashers can be made with traditional technology and acceptable costs. Therefore producers have, during recent years, started looking for less traditional methods, for example the use of a heat pump to reduce the energy use.</p><p>The purpose of this examination work has been to find system solutions for an application of a heat pump in a dishwasher and to evaluate the possible energy saving for each solution.</p><p>The goal has been to find and describe possible system solutions, which came up during the idea generation. To choose some of these for a closer investigation, to decide a fitting mechanical power for the compressor and to calculate the energy saving these solutions give rise to.</p><p>The method has consisted of a literature study, an idea generation, which takes the heat sources and sinks in consideration and a modelling in MATLAB’s Simulink of the selected solutions from the idea generation, which has been used to fit a mechanical power for the compressor.</p><p>The result of the idea generation was two solutions, an outdoor air solution, which collects heat from the outdoor air and gives it to the cold water which enters the machine and a energy storage solution, which collect heat from a heat stock to give to the cold entering water. A modelling of these show an energy usage of 0,24 respectively 0,17 kWh for the outdoor air solution, with a heat source temperature at 10 °C respectively 5°C and a energy usage of 0,22 kWh for the energy storage solution for one round.</p><p>The conclusion that was drawn was that the compressor of the energy storage solution should deliver a mechanical power of 240 W to the refrigerant.</p>

The tendency to use renewable energy resources has grown continuouslyover the past few decades, be it due to fear over warnings of globalwarming or because of the depletion and short life of fossil fuels or evenas a result of the interest which has developed among researchers doingscientific research into it. This work can be considered as joining any ofthese groups with an objective of giving electric light to the poorpopulation living in one of the poorest nations in the world.The aim of the work is to investigate supplying electric energy fromsolar-wind hybrid resources to remotely located communities detachedfrom the main grid line in Ethiopia. The communities in mind are one oftwo types; the first is the majority of the poor population residing in thecountryside; and the other is people relocated by the Government fromthe over used and dry regions to relatively productive and fertile ones inline with the long-term poverty reduction plan.The work was begun by investigating wind energy and solar energypotentials at four geographically different locations in Ethiopia bycompiling data from different sources and analyzing it using a softwaretool. The locations are Addis Ababa (09:02N, 038:42E), Mekele (13:33N,39:30E), Nazret (08:32N, 039:22E), and Debrezeit (8:44N, 39:02E).The results related to wind energy potential are given in terms of themonthly Average wind speed, the wind speed probability densityfunction (PDF), the wind speed cumulative density function (CDF), thewind speed duration curve (DC), and power density plots for all fourselected sites. According to the results obtained through the analysis, thewind energy potential, even if it is not exceptional, is irrefutably highenough to be exploited for generating electric energy.The solar energy potential, based on sunshine duration data collectedover a period of 7 - 11 years and radiation data obtained from differentsources, has been calculated using regression coefficients specific to thesites in question. Based on the sunshine duration data, the monthlyaverage daily sunshine amount for each of the places has also beencomputed and given in a form of plot. Through additional work on theresults of the calculations, the solar energy potential has been given inthe form of solar radiation plots for each of the selected sites. Asexpected, the results indicated an abundance of solar energy potential.It is based on the promising findings of these two energy resourcepotentials, wind and solar, that the feasibility study for a standalonesolar-wind hybrid energy supply system has proceeded, targeting thecommunity mentioned earlier. The hybrid system consisted of Windturbine, Photovoltaic panel, diesel generator and a bank of batteries, witha power conditioning converter included in the system.The hybrid standalone supply system is intended to provide electricity toa model community of 200 families with five to six family members ineach. The community is equipped with a primary load, a deferrable load,a community school and a health post. An electric load which includeslighting, water pumping, a radio receiver, and some clinical equipmenthas been suggested. Hybrid Optimization Model for ElectricRenewables, HOMER, software has been used for the analysis. Theaverage wind speed and average solar radiation calculated from the datafor all of the selected sites has been used to input into the software.The hybrid system design is approached in three different ways. The firstapproach is to include within the hybrid system those components whichare locally available, without giving special attention to their efficienciesand proceed with the design work. The second approach is tothoroughly search the market for the best and most efficienttechnological products and to select the best components for theanalysis. A third approach considered in an attempt of cost minimizationis to see if a self-contained type of design can be a better solution. Whatthis means is every household will have its own supply system that mayconsist of any combination of PV and wind turbine including converter,battery and charge controller.After running the simulations, lists of power supply systems have beengenerated, sorted according to their net present cost. Sensitivity variables,such as range of wind speeds, range of radiation levels and diesel pricehave been defined as inputs into the software and the optimizationprocess has been carried out repeatedly for the sensitivity variables andthe results have been refined accordingly. / QC 20100623

Thermal energy storage (TES) is an advanced technology for storing thermal energy that can mitigate environmental impacts and facilitate more efficient and clean energy systems. Thermochemical TES is an emerging method with the potential for high energy density storage. Where space is limited, therefore, thermochemical TES has the highest potential to achieve the required compact TES. Principles of thermochemical TES are presented and thermochemical TES is critically assessed and compared with other TES types. The integration of TES systems with heating, ventilating and air conditioning (HVAC) applications is examined and reviewed accounting for various factors, and recent advances are discussed. Thermodynamics assessments are presented for general closed and open thermochemical TES systems. Exergy and energy analyses are applied to assess and compare the efficiencies of the overall thermochemical TES cycle and its charging, storing and discharging processes. Examples using experimental data are presented to illustrate the analyses. Some important factors related to design concepts of thermochemical TES systems are considered and preliminary design conditions for them are investigated. Parametric studies are carried out for the thermochemical storage systems to investigate the effects of selected parameters on the efficiency and behavior of thermochemical storage systems. / UOIT

För ett genomsnittligt småhus i Sverige idag går ca 5000 kWh till hushållsel. Av dessa 5000 kWh går 7% till att driva diskmaskiner. Effektiviseringen av diskmaskiner har framförallt strävat efter en låg vatten- och energianvändning, en kort processtid samt en effektiv rening av disken. Det finns dock gränser för hur effektiva diskmaskinerna kan göras med traditionell teknik. Därför har producenter under de senaste åren börjat se sig om efter mindre traditionella metoder som till exempel bruket av en värmepump för att få ned energiförbrukningen. Syftet med det här examensarbetet har varit att ta fram systemlösningar för värmepump i diskmaskin samt att utvärdera energibesparingspotentialen i denna tillämpning. Målet har varit att ta fram och beskriva de möjliga systemlösningar som uppstår vid en idégenerering. Att välja ut två lösningar för närmare undersökning, att bestämma en lämplig kompressoreffekt samt att beräkna energibesparingen dessa lösningar ger. En litteraturstudie har gjorts av teknik och tillämpningar inom området, som till exempel värmeväxlaranvändning i diskmaskiner samt användandet av värmepumpar i andra vitvaror. Denna litteraturstudie följdes upp av en idégenerering, som tar hänsyn till möjliga värmekällor och –sänkor. Idégenereringen gav upphov till två systemlösningar som modellerades i MATLABs Simulink för att en lämplig kompressoreffekt och storleken på energibesparingen skulle bestämmas. De två utvalda lösningarna ifrån idégenereringen var utomhusluftlösningen, där värme hämtas från uteluften och energilagerlösningen, där värme hämtas ur ett energilager. I båda lösningarna överförs värmen till det kalla ingående vattnet. Energiåtgången för utomhusluftlösningen var beroende av köldmediets förångningstemperatur och modellering av lösningen visade att energiåtgången var 0,25 kWh vid en förångningstemperatur på -10°C, och 0,18 kWh vid 5°C. Vid modellering av energilagerlösningen påvisades en energiåtgång på 0,23 kWh. Slutsatsen som drogs var att kompressorn vid energilagerlösningen skall leverera en effekt på 240 W till köldmediet. / For an average detached house in Sweden today about 5000 kWh are used for household electricity. Of these 5000 kWh 7% are used to run dishwashers. The streamlining of dishwashers has above all strived for a lower water and energy use, a short process time along with a more efficient cleaning of the dishes. There are however limits for how efficient the dishwashers can be made with traditional technology and acceptable costs. Therefore producers have, during recent years, started looking for less traditional methods, for example the use of a heat pump to reduce the energy use. The purpose of this examination work has been to find system solutions for an application of a heat pump in a dishwasher and to evaluate the possible energy saving for each solution. The goal has been to find and describe possible system solutions, which came up during the idea generation. To choose some of these for a closer investigation, to decide a fitting mechanical power for the compressor and to calculate the energy saving these solutions give rise to. The method has consisted of a literature study, an idea generation, which takes the heat sources and sinks in consideration and a modelling in MATLAB’s Simulink of the selected solutions from the idea generation, which has been used to fit a mechanical power for the compressor. The result of the idea generation was two solutions, an outdoor air solution, which collects heat from the outdoor air and gives it to the cold water which enters the machine and a energy storage solution, which collect heat from a heat stock to give to the cold entering water. A modelling of these show an energy usage of 0,24 respectively 0,17 kWh for the outdoor air solution, with a heat source temperature at 10 °C respectively 5°C and a energy usage of 0,22 kWh for the energy storage solution for one round. The conclusion that was drawn was that the compressor of the energy storage solution should deliver a mechanical power of 240 W to the refrigerant.

Analizuojamos esamo gyvenamojo kvartalo, nutolusio nuo pagrindinės gyvenvietės aprūpinimo šilumine energija galimybės Širvintų mieste. Įvertinama esama gyvenamojo kvartalo geografinė padėtis bei specifika. Analizuojami kvartalo aprūpinimo šilumine energija būdai. Vertinama esamų trasų renovacija, bei dujomis arba malkomis kūrenamos katilinės šalia analizuojamo kvartalo įrengimas. Pateikiamas išlaidų, susijusių su trasų renovavimu bei katilinių įrengimu, vertinimas bei palyginimas. Pateikiamas katilinių poveikio aplinkai skaičiavimas. / In the final master work I have analyzed the supplying thermal energy to the existing residential quarter in Sirvintai city which is moved away from the main city. Also there is evaluated the existing geographical situacion and specific features of this residential quarter. The means of the suppling thermal energy to the residential quarter also is analyzing in this work. The revovation of existing tracks and the mounting the boiler-houses where the gas or wood is used and which are close to the residential quarter are evaluated in this paper work too. The expenses which is retaled to the renovation of heating tracks and boiler-houses mounting are estimated and compared. The calculation of the boiler-houses influence to the environment is also presented in this work.

Pagrindinis darbo tikslas- atlikti įstatymais nustatytų socialinių išmokų ir kompensacijų administravimo ir teikimo analizę Šilalės rajono savivaldybėje, įvertinti ir pateikti siūlymus dėl kompensacijų sistemos tobulinimo. Siekiant šio tikslo pirmiausiai aptarta Lietuvos socialinės paramos samprata, paramos poreikio atsiradimo priežastys, išanalizuoti ir susisteminti socialinės paramos ir pašalpų skyrimo principai, pateiktos piniginės socialinės paramos sistemos tobulinimo kryptys. Atlikta Lietuvos socialinės paramos šeimoms analizė. Patvirtinta suformuluota hipotezė, kad dabartinė pajamų kompensavimo sistema mažina darbo paskatas ir skatina žmones gyventi iš pašalpų. / The mani purpose-to carry out statutory social security benefits and compensation administration Šilalė analysis of the provision in the municipality to evaluate and provide suggestions for improving the system of compensation. To this end, in particular Lithuania discussed the concept of social support, the need to support causes, and to analyze the structure of social support and the award of grants provided financial support for improving the system of social trends. Analysis of the Lithuanian social analysis to support the family. Approved and formulated the hypothesis that the current system of income compensation reduces work incentives and encourage people to live on benefits.