Sunshine, air and water are the vital elements to the human. This study investigated the insolation and solar radiation in Kaohsiung city. Solar radiation on the horizontal and declined plane was calculated. Sun shadow model for urban buildings was constructed for computing accumulated sunshining hours. Horizontal and vertical building shadows were displayed in ArcGIS ¡V the GIS software. Raster-based data model was used to analyze the effect of sun shadow shading by neighbour buildings. And the effect of shadow shading for solar water heater was also investigated. According to the results, minor installation error of orientation and decline angles of solar panel will not cause major energy loss. And the distance between the buildings¡Bthe height difference and the orientation between buildings are most important factors which affect optimal installation location of the solar water heater. If there are buildings located to the south, southeast and southwest, and the stories difference between buildings is over three, the installing location should be moved toward north. If buildings are next to each others and the variation of height is large, the efficient of receiving solar radiation will be deteriorated. The larger is the distance between buildings, the better the energy received.

Nanofluids have been demonstrated to be promising for heat transfer enhancement in forced convection and boiling applications. The addition of carbon, copper, and other high-thermal-conductivity material nanoparticles to water, oil, ethylene glycol, and other fluids has been determined to increase the thermal conductivities of these fluids. The increased effective thermal conductivities of these fluids enhance their abilities to dissipate heat in such applications. The use of nanofluids for spray cooling is an extension of the application of nanofluids for enhancement of heat dissipation. In this investigation, experiments were performed to determine the level of heat transfer enhancement with the addition of alumina nanoparticles to the fluid. Using mass percentages of up to 0.5% alumina nanoparticles suspended in water, heat fluxes and surface temperatures were measured and compare. Compressed nitrogen was used to provide constant spray nozzle pressures to produce full-cone sprays in an open loop spray cooling system. The range of heat fluxes measured were for single-phase and phase-change spray cooling regimes.

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The purpose of this study is to investigate the performance of a spherical solar collector by using numerical and experimental methods. For this analysis, equations were obtained by choosing appropriate control volumes in the system and applying The First Law of Thermodynamics. The experiments were realized at four different mass flow rates and non-flow situation. For the numerical simulation of the system, a computer program in Mathcad was written. Another computer program in Mathcad was written for the variation of the absorbed solar radiation through out the day. Finally, the performance of the spherical solar collector is compared theoretically to that of flat plate solar collectors.

No projeto de um forno, normalmente busca-se uma configuração para a posição dos aquecedores que resulte em aquecimento uniforme na superfície inferior, a superfície de projeto. Neste trabalho, o fluxo de calor e a temperatura são prescritos na superfície de projeto e os elementos aquecedores devem ser projetados em um conjunto de quatro filamentos, ou um filamento em cada quarto simétrico do forno, a fim de satisfazer às condições prescritas. O forno é modelado como uma cavidade tridimensional preenchida com meio transparente; assume-se que as paredes sejam cinzas e difusas e que o único mecanismo de transferência de calor presente é a radiação térmica. Esse problema, convencionalmente, é solucionado através de um procedimento de tentativa-e-erro; neste trabalho, a solução é obtida através da análise inversa, uma técnica mais versátil e eficaz de projeto, embora exija tratamentos matemáticos especiais. O problema inverso é resolvido nesta pesquisa de forma implícita, como um problema de otimização. A solução é obtida através do método da Otimização Extrema Generalizada (GEO), um método de otimização estocástico e global, utilizado para encontrar as posições para os aquecedores respeitando a condição de formar um filamento. A metodologia é aplicada para se obter a configuração geométrica e posição do filamento aquecedor, uma abordagem inédita na literatura, conduzindo a resultados com desvio máximo inferior a 2%. Por fim, nesta pesquisa, realiza-se um estudo acerca do fator de forma dos elementos aquecedores que indica a aplicabilidade da solução obtida para filamentos com diferentes espessuras. / In the design of a oven is desired to obtain the positions for the heaters that results in a uniform heating to the bottom surface, the design surface. The heat flux and temperature are prescribed in the design surface and the heating elements are positioned in a single filament so as to satisfy prescribed conditions. The oven is modeled as a three-dimensional cavity filled with transparent medium, it is assumed that the walls are gray and diffuse and the dominant heat transfer mechanism is thermal radiation. This problem, conventionally, is solved through a trial and error procedure, in this work, the solution is obtained by inverse analysis. The inverse problem is solved implicitly, as an optimization problem. The solution is obtained by the method of optimization extreme (GEO) a stochastic global optimization method used to find the locations for the heaters respecting the condition of build a filament. The methodology leads to satisfactory results, with maximum error less than 2%. Finally, this research, realized a study of the view factor of the elements heaters that indicates the applicability of the solution into filaments with different thicknesses.

[pt] Análise numérica do processo dinâmico do escoamento de gás natural em estações de entrega, considerando o comportamento transiente dos principais equipamentos existentes, tais como válvula de três vias, válvulas redutoras de pressão e aquecedores de gás. Desenvolvimento da lógica de controle dinâmica (controle PID - proporcional-integral-derivativo) de todos os equipamentos relevantes. Para determinação das propriedades termodinâmicas do gás natural empregou-se as equações de estado Peng-Robinson e Soave-Redlich-Kwong. O estudo apresenta um maior enfoque na análise do comportamento de aquecedores de gás indireto a banho d’água e na regulagem dinâmica da temperatura de entrega através de um controlador PID que comanda a válvula de três vias. Investigou-se o desempenho de uma estação de entrega de gás natural existente baseada nas condições operacionais estabelecidas no projeto. Simulou-se o escoamento correspondente a operação em uma estação de entrega real e realizou-se comparação direta com dados de instrumentação enviados ao supervisório de controle e aquisição de dados (SCADA). A metodologia desenvolvida reproduziu de forma adequada a operação em condições normais da estação de entrega de São Carlos-SP e eventos anormais como cenários de apagamento dos aquecedores que foram registrados no banco de dados do supervisório. Finalmente analisaram-se procedimentos a serem aplicados nas estações de entrega existentes para redução do consumo do gás combustível utilizado no processo de pré-aquecimento. / [en] Numerical simulation of the dynamic process of natural gas flow through citygate stations, considering the transient behavior of the main existing equipments, such as three-way-valves, pressure reduction valves and gas heaters. Development of the dynamic control logic (PID controller) of all relevant equipments. To determine the natural gas thermodynamic properties, the equations of state of Peng-Robinson and Soave-Redlich-Kwong were employed. The study concentrates in the analysis of indirect fired water bath heater and in the delivery temperature regulation using a PID controller that commands the three-way-valve. It was investigated the performance of an existing natural gas citygate station based on established design operational conditions. The flow field corresponding to an operational natural gas city gate station was determined and direct comparison with instrumentation data sent to supervisory control and data acquistion (SCADA) was performed. The methodology developed reproduced in a satisfactory way the normal operational condition of the São Carlos-SP natural gas citygate station and abnormal events such as the heater shut-down scenarios registered on SCADA database. Finally, procedures to be applied in existing delivery stations for the reduction of gas fuel consumption in the pre-heating process were analyzed.

abstract: Improving the conditions of schools in many parts of the world is gradually acquiring importance. The Green School movement is an integral part of this effort since it aims at improving indoor environmental conditions. This would in turn, enhance student- learning while minimizing adverse environmental impact through energy efficiency of comfort-related HVAC and lighting systems. This research, which is a part of a larger research project, aims at evaluating different school building designs in Albania in terms of energy use and indoor thermal comfort, and identify energy efficient options of existing schools. We start by identifying three different climate zones in Albania; Coastal (Durres), Hill/Pre-mountainous (Tirana), mountainous (Korca). Next, two prototypical school building designs are identified from the existing stock. Numerous scenarios are then identified for analysis which consists of combinations of climate zone, building type, building orientation, building upgrade levels, presence of renewable energy systems (solar photovoltaic and solar water heater). The existing building layouts, initially outlined in CAD software and then imported into a detailed building energy software program (eQuest) to perform annual simulations for all scenarios. The research also predicted indoor thermal comfort conditions of the various scenarios on the premise that windows could be opened to provide natural ventilation cooling when appropriate. This study also estimated the energy generated from solar photovoltaic systems and solar water heater systems when placed on the available roof area to determine the extent to which they are able to meet the required electric loads (plug and lights) and building heating loads respectively. The results showed that there is adequate indoor comfort without the need for mechanical cooling for the three climate zones, and that only heating is needed during the winter months. / Dissertation/Thesis / Masters Thesis Architecture 2015

abstract: The complicated, unpredictable, and often chaotic hot water usage pattern of typical households severely limits the effectiveness and efficiency of traditional solar hot water heater systems. Similar to large scale concentrating solar power plants, the use of thermal energy storage techniques to store collected solar energy as latent heat has the potential to improve the efficiency of solar hot water systems. Rather than being used to produce steam to generate electricity, the stored thermal energy would be used to heat water on-demand well after the sun sets. The scope of this thesis was to design, analyze, build, and test a proof of concept prototype for an on-demand solar water heater for residential use with latent heat thermal energy storage. The proof of concept system will be used for future research and can be quickly reconfigured making it ideal for use as a test bed. This thesis outlines the analysis, design, and testing processes used to model, build, and evaluate the performance of the prototype system. The prototype system developed to complete this thesis was designed using systems engineering principles and consists of several main subsystems. These subsystems include a parabolic trough concentrating solar collector, a phase change material reservoir including heat exchangers, a heat transfer fluid reservoir, and a plumbing system. The system functions by absorbing solar thermal energy in a heat transfer fluid using the solar collector and transferring the absorbed thermal energy to the phase change material for storage. The system was analyzed using a mathematical model created in MATLAB and experimental testing was used to verify that the system functioned as designed. The mathematical model was designed to be adaptable for evaluating different system configurations for future research. The results of the analysis as well as the experimental tests conducted, verify that the proof of concept system is functional and capable of producing hot water using stored thermal energy. This will allow the system to function as a test bed for future research and long-term performance testing to evaluate changes in the performance of the phase change material over time. With additional refinement the prototype system has the potential to be developed into a commercially viable product for use in residential homes. / Dissertation/Thesis / Masters Thesis Engineering 2015

Orientador: João Francisco Escobedo / Banca: Eduardo Nardini Gomes / Banca: Alexandre Dal Pai / Resumo: O presente trabalho descreve a construção de um coletor solar alternativo de concreto de tração simples (areia, cimento e pedra), para aplicações agrícolas e agroindustriais. o coletor é constituído de uma área de absorção 51 m2 com 470m de mangueira de polietileno para o aquecimento da água, e o armazenador da água aquecida. O sistema coletor e armazenador foi submetido a testes experimentais onde foram determinados para as estações verão e inverno, e sob três coberturas de céu aberto, parcialmente nublada e nublada: as temperatura do absorvedor em três profundidades; ganho térmico do fluido; rendimento térmico do coletor, e desempenho do armazenador. Os resultados mostram que a temperatura do absorvedor foi maior na cobertura de céu aberto, decrescendo em seqüência de profundidade 55,74ºC, 52,10C e 49,30C respectivamente, e foi menor na cobertura de céu nublado, 48,30C, 46,20C e 44,60C respectivamente; o ganho térmico do fluido de trabalho no absorvedor foi decrescente em função do aumento comprimento do condutor: o ganho foi maior no verão e em dias de céu aberto, atingindo a temperatura máxima de 52,70C, e foi menor no inverno, em dias céu nublado, atingindo a temperatura máxima de 28,50C; o rendimento térmico do coletor foi maior em dia de céu aberto: no verão 71,4% e inverno 74%; o sistema armazenador térmico, mostrou ótimo desempenho na conservação da temperatura do fluido de trabalho. Nos dias estudados houve uma redução de 10% na temperatura final da água aquecida / Abstract: This paper describes the construction of an alternative sidewalk-type solar collector made of concrete (sand, cement and stone), for agriculture and agribusiness uses. The collector consists of an absorption area of 51 m2 with 470m polyethylene tubing for water heating, and a storage for warm water. The collector and storage systems were subjected to experimental tests which were determined for summer and winter, three sky conditions: open skies, partly cloudy and overcast; three depths temperature in the absorber; thermal gain of the fluid, thermal efficiency of the collector and performance of the water storage. The temperature of the absorber was higher in open sky conditions: 55,74ºC above it, decreasing in depth sequence of 52,1ºC and 49,3ºC. This temperatures of the absorber were 48,3ºC 46,2ºC and 44,6ºC respectively in a overcast days. The thermal gain of the working fluid in the absorber was decreasing with increasing length of the conductor: the gain was higher in summer and open sky days, reaching a maximum temperature of 52.7 ºC, and lowest in winter cloudy days, reaching a maximum temperature of 28.5 ºC. The collector thermal efficiency was higher in open sky days: 71.4% in summer and 74% in winter. The warm water storage system had excellent keeping temperature performance with 10% loss in the final water temperature / Mestre

Este trabalho aborda o desenvolvimento de um sistema de controle de temperatura para um aquecedor de passagem de água a gás. O sistema de controle Controlgás é apresentado e comparado ao sistema de controle típico, usado em aquecedores de passagem convencionais. São apresentadas as características e objetivos do projeto Controlgás, o qual serviu de base para o desenvolvimento deste trabalho. É apresentada uma fundamentação teórica sobre técnicas de controle para compensação de variações paramétricas e de atrasos de transporte, bem como uma revisão sobre as principais soluções já desenvolvidas para o controle de temperatura da água em aquecedores de passagem. A bancada experimental, contendo o aquecedor e o sistema de controle, utilizada em trabalhos anteriores, foi reestruturada e instrumentada com sensores de temperatura na entrada e na saída de água e com sensores que detectam a presença de chama e de fluxo de água. Foi desenvolvida uma servo-válvula que permite a regulagem automática da vazão de gás. Desenvolveu-se um circuito de potência para o acionamento dos atuadores (solenoides e servo-válvula) da bancada, assim como algoritmos que geram os sinais adequados para seu funcionamento. Foi feita a identificação do processo e o modelo da servo-válvula foi obtido por meio da análise de ensaios experimentais. O modelo do sistema completo foi desenvolvido no programa Simulink, onde foram feitas simulações do comportamento dinâmico do sistema proposto. O sistema foi implantado experimentalmente e foi capaz de convergir para as temperaturas de referência durante os ensaios. / This work addresses the development of a temperature control system for a gas tankless water heater. The Controlgás control system is presented and compared to typical control systems used in regular tankless water heaters. The characteristics and objectives of Controlgás project, which formed the basis for the development of this work, are presented. A theoretical foundation on control techniques for compensation of parametric variations and transport delays is presented, as well as a review of the main solutions already developed for the control of water temperature on tankless water heaters. The experimental set containing the heater and the control system used in previous work was restructured and instrumented with temperature sensors at the water's input and output and with sensors which detect the presence of flame and the water flow. A servo-valve that allows automatic adjustment of the gas flow was developed. A power circuit was created to drive the actuators (solenoids and servo-valve) of the set, as well as algorithms that generate the appropriate signals for its operation. The process identification and the servo-valve‟s model were obtained through experimental analysis. The system‟s complete model was developed in Simulink, where simulations of the dynamic behavior of the proposed system were made. The system was implemented experimentally and was able to converge to the reference temperatures during the tests.