An experimental characterisation of a pre-commercial spiral wound permeate gap membrane distillation module was carried out to test its performance at different operating conditions for the purpose of seawater desalination. The experimental setup consisted of a flat plate solar collector field indirectly coupled to the permeate gap membrane distillation module via an inertia tank. The operating parameters varied were the condenser inlet temperature (from 20 °C to 30 °C), evaporator inlet temperature (from 60 °C to 80 °C) and seawater feed flow rate (from 200 l/h to 400 l/h). Within this operational boundary, it was found that the maximum permeate/distillate flux was 4.135 l/(h∙m2) which equates to a distillate production/flow rate of close to 21.3 l/h. The maximum potential distillate production rate is expected to be significantly higher than this value though as the maximum manufacturer specified feed flow rate is 700 l/h and the maximum evaporator inlet temperature is rated at 90 °C. Both these parameters are positively related to the distillate production rate. The minimum specific thermal energy consumption was found to be 180 kWh/m3. A mathematical model of the overall system was developed, and experimentally validated, to mathematically describe the coupling of the membrane distillation module with a solar collector field. The effectiveness of internal heat recovery of the membrane distillation module was found to be an accurate and simple tool to evaluate the thermal energy demand of the distillation process at a given set of operation parameters. The mathematical model was used to further investigate the experimental findings and provide insights into the operational dynamics of the membrane distillation module. It was also used to determine some external conditions required for steady state operation, at a given distillation operating point, such as the minimum solar irradiation required for operation and the auxiliary cooling required in the solar collector loop for maintaining steady state conditions. Finally, general guidelines are provided toward better operational practices to improve the coupling of a solar thermal collector unit/field with a membrane distillation system using a storage tank or inertia tank.

Orientador: Vicente Luiz Scalon / Coorientador: Alcides Padilha / Banca: Ismael de Marchi Neto / Banca: Celso Luiz da Silva / Resumo: Atualmente, a aplicação da energia solar térmica para aquecimento de água é uma solução técnica e economicamente viável permitindo a redução do consumo de energia elétrica no setor residencial, comercial e industrial. Diante disto, se faz cada vez mais necessário o domínio de metodologias que permitam quantificar a energia térmica útil captada pelos coletores solares e determinar a sua eficiência na geração de água quente. Como uma forma de contribuir para esta meta, este trabalho desenvolve uma análise comparativa da captação de energia térmica no coletor solar plano. A partir de dados experimentais e teóricos, diferentes modelos para tratamento dos dados foram aplicados e comparados. A metodologia do trabalho consistiu em monitorar um sistema de aquecimento solar residencial, em condições reais de uso e, a partir dos dados obtidos, calcular e comparar a captação de energia térmica útil nos coletores solares baseando-se no balanço energético pela Primeira Lei da Termodinâmica e pelo Método de Eficiência Térmica Instantânea. A irradiação solar global incidente nas placas da placa solar plano também foi monitorada e, portanto, seu valor foi comparado ao modelo teórico. Por fim, a demanda mensal de energia térmica para consumo de água quente da residência também foi monitorada e comparada à captação mensal de energia. A aplicação mostrou coerência entre os resultados experimentais e teóricos em grande parte dos casos, algumas inconveniências em determinadas situações e oportuni... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Currently, the application of solar thermal energy for water heating is a technical and economically viable solution allowing the reduction of electricity consumption in the residential, commercial and industrial sector. Given this, it is increasingly the domain methodologies that enable more necessary to quantify the useful thermal energy captured by solar collectors and determine their efficiency in the generation of hot water. As a way to contribute to this goal, this paper develops a comparative analysis of thermal energy harvesting in flat solar collector. From experimental and theoretical data, different models for processing the data were applied and compared. The methodology of the study was to monitor a residential solar heating system in real conditions of use and, from the data calculate and compare the uptake of useful thermal energy in solar collectors based on the energy balance of the First Law of Thermodynamics and by the Instantaneous Thermal Efficiency Method. The global solar radiation incident on the places of the solar collector plane was also monitored and therefore its value was compared to the theoretical model. Finally, the monthly demand for hot water thermal energy consumption of the house was also monitored and compared to the monthly energy harvesting. The application showed consistency between experimental and theoretical results in most cases, some inconveniences in certain situations and opportunities for improvements, in what is considered good design practice, as highlighted in the work / Mestre

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016. / South Africa has raised concerns regarding the development of renewable energy sources such as wind, hydro and solar energy. Integration of a combined photovoltaic and thermal system was considered to transform simultaneous energy into electricity and heat. This was done to challenge the low energy efficiency observed when the two solar energy conversion technologies are employed separately, in order to gain higher overall energy efficiency and ensure better utilization of the solar energy. Therefore, the notion of using a combined photovoltaic and thermal system was to optimize and to improve the overall PV panel efficiency by adding conversion to thermal energy for residential and commercial needs of hot water or space heating or space cooling using appropriate technology. The PV/T model constructed using water as fluid like the one used for the experimental work, presented a marginal increase in electrical efficiency but a considerable yield on the overall PV/T efficiency, because of the simultaneous operation by coupling a PV module with a thermal collectors.

Orientador: Teófilo Miguel de Souza / Coorientador: José Antonio Perrella Balestieri / Banca: José Feliciano Adami / Banca: Paulo Cesar Boggiani / Resumo: A disponibilidade de luz solar, transformada em energia, pode ser capturada em quase todo o mundo. Desde a década de 1990 o mercado da utilização de energia solar vem crescendo, porém informações sobre estudos de caso para a avaliação da inserção de aquecedores solares de água nos domicílios populares brasileiros ainda são escassas. O presente trabalho visa contribuir para reduzir essa carência e tem como objetivo avaliar a viabilidade técnica e econômica da inserção de aquecedores solares de água nas residências populares no município de Tremembé, localizado no Vale do Paraíba, estado de São Paulo, Brasil. O município de Tremembé possui uma área de 192 km² e conta com uma população de 42.027 habitantes, sendo um total de 10.632 domicílios. A avaliação foi efetuada numa amostra setorial do total de domicílios, através de um plano amostral aleatório estratificado, metodologia que permite conhecer melhor as características próprias de cada setor do município estudado. A pesquisa de campo foi efetuada com o método survey, com o total de 360 questionários, os quais foram aplicados a um representante de cada família. Imagens com as descrições e atributos dos setores censitários do IBGE foram tratadas no formato de extensão kmz. Foi necessária a construção de um cadastro no programa Excel para inserir os dados colhidos em campo e esses dados foram sobrepostos aos layers das imagens tratadas. O resultado desta pesquisa mostrou aceitação generalizada da população à possibilidade de instalações e utilização de sistemas de aquecimento solar de água, especialmente nas áreas rurais, principalmente por apresentar custo reduzido de energia elétrica no pico e aponta para a redução da demanda na rede elétrica. A pesquisa comprova que com a utilização de energia solar, o município pode economizar 31.680.000 kWh/ano, o que corresponde a R$ 9.504.000,00 /ano / Abstract: The availability of sunlight converted into energy can be captured throughout the world. Since the 1990s the market for the use of solar energy has been growing, but information on case studies to assess the inclusion of solar water heaters in the popular Brazilian households are still scarce. The present work aims at contributing to reduce this gap and aims to assess the technical and economic feasibility of integration of solar water heaters in low-income households in the municipality Tremembé, located in the Paraíba Valley, State of São Paulo, Brazil. Tremembé has an area of 192 km ² and has a population of 42,027 inhabitants, with 10,632 households. The evaluation has done on a sectorial sample of total households. Effected through a stratified aleatory sampling plan, as this methodology allows better understanding the characteristics of each sector of the municipality. The field research was conducted with the survey method, with 360 questionnaires, which have been applied to a representative of each family. Images with descriptions and attributes of the official census sectors of IBGE have been treated in the extension kmz format. It was necessary to build a register in Excel to insert the data collected in the field and these data were overlaid on the images Leyers treated. The result of this research showed widespread acceptance of the population the possibility of facilities and use of solar water heating systems, especially the rural areas, mainly by presenting reduced cost of electric power in peak and points to reduced demand in the power grid. The research proves that with the use of solar energy, the city may save 31, 68 million kWh/year, which corresponds to R$ 9,504,000.00/ year / Mestre

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / A solar desalination system basically has two components: the heating unit (solar collectors) and the desalination unit (tower). Among its main advantages, this device does not need electrical power to operate, since it is driven by thermosiphon. In its operation, brackish water is heated and it evaporates. The evaporated vapor rises and hits the coller walls of the above tray, where it condensates and drains through a specially designed geometry, structure to be finally by in a set of gutter. The already demineralized water flows through a main channel where it is stored in a container, outside the desalination tower. The resulting water from this process is pure and free from contamination, either microorganisms or salt. This study analyzes the performance of a desalination system with a desalination tower and a set of three solar collectors. The heat transfer medium between the collector and the tower was thermal oil flow, Lubrax Utile OT-100. The experimental results demonstrate the operation of this type of desalinator, since ideal conditions for its correct functioning was only achieved after the installation of a positive displacement pump, which that promoted the oil circulation. Thermocouples installed in the stages of tower registered the temperature increase throughout the day. Peaks of 77 ÂC were measured in the storage tank of the tower. The mean values of production per day were 25 liters of desalinated water with an average conductivity always less than 10 μS / cm Â, representing a salt removal efficiency greater than 99%. In performance calculation, the best result was obtained when the pumping system was combined with the use of a solar reflector, achieving GOR value of 2.85. / Um dessalinizador solar possui basicamente duas unidades: a unidade de aquecimento (coletora) e a unidade de dessalinizaÃÃo (torre). Apresenta entre suas principais vantagens o fato de nÃo precisar de energia elÃtrica para seu funcionamento, pois à acionada por termossifÃo. A operaÃÃo se dà pelo aquecimento da Ãgua salobra atà que esta comece a evaporar. O vapor, ao subir e encontrar com uma superfÃcie com temperatura inferior, condensa e escorre atravÃs de estruturas em uma geometria especialmente projetada para este fim e sà entÃo à coletada por um sistema de calhas. A Ãgua jà desmineralizada segue por uma calha principal onde escorre e à armazenada em um recipiente, jà fora da torre de dessalinizaÃÃo. A Ãgua resultante desse processo à praticamente pura e isenta de contaminaÃÃo, tanto por microrganismos como por sais e outros contaminantes. O presente trabalho analisa o desempenho do dessalinizador composto por uma torre de dessalinizaÃÃo e um conjunto composto por trÃs coletores solares acionados por Ãleo tÃrmico Lubrax Utile OT-100. Os resultados experimentais comprovam o funcionamento desse tipo de dessalinizador, visto que condiÃÃes ideais para seu correto funcionamento sà foram atingidas graÃas à instalaÃÃo de uma bomba de deslocamento positivo que promoveu a circulaÃÃo do Ãleo. Termopares instalados nos estÃgios da torre registraram o aumento de temperatura ao longo do dia. Picos de 77ÂC foram medidos no tanque de armazenamento da torre. Valores mÃdios de produÃÃo por dia sÃo de 25 litros de Ãgua, com uma condutividade mÃdia sempre inferior a 10 μS/cmÂ, o que representa uma eficiÃncia na remoÃÃo de sais superior a 99%. No cÃlculo de desempenho, o melhor resultado foi obtido quando o sistema de bombeamento foi combinado com o uso de um refletor solar, obtendo o valor do GOR (RazÃo de ganho de saÃda) de 2,85.

Orientador: José Antonio Siqueira Dias / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-16T16:32:34Z (GMT). No. of bitstreams: 1 Florio_JoaoLuiz_M.pdf: 3876077 bytes, checksum: 656fc1412001c5a7dcda51118870e94a (MD5) Previous issue date: 2010 / Resumo: Mais de 90% dos sistemas de aquecimento de água por energia solar instalados no Brasil (número superior a 700.00 instalações) são do tipo convencional por circulação passiva. Esse tipo de instalação apresenta boa performance, aliada à simplicidade de funcionamento. Considerando-se que aproximadamente 8% da energia consumida em nosso país é para o aquecimento de água residencial, trata-se de uma excelente alternativa ecológica de economia de energia. Em períodos de baixa insolação, o usuário pode contar com um aquecimento auxiliar através de um resistor instalado no interior do reservatório (boiler).Nesta situação a temperatura da água até atingir o valor de desligamento do termostato de segurança do sistema.Não havendo o acompanhamento da temperatura, o sistema entra num regime de funcionamento de sucessivos períodos e aquecimento e resfriamento (por perdas de calor), até que o usuário lembre-se de desligar o disjuntor. Este trabalho apresenta uma solução economicamente viável de se melhorar essa situação, fazendo-se uso da eletrônica microcontrolada. Assim, pode-se monitorar o aquecimento da água pelo resistor auxiliar através de sensores do tipo NTC, propiciando uma economia de até 25% na conta mensal, além de outras comodidades. Possuindo três modos de operação : temporizado (atua como timer), termostato (termostato ajustável pelo painel) e programado (o usuário determina o momento de uso e a temperatura desejada da água) , o sistema é constituído por console de controle e unidade de potência. O sistema é de fácil instalação, constituindo uma alternativa viável para se melhorar significativamente a performance dos sistemas atuais / Abstract: Over 90% of heating water by solar energy installed in Brazil today (more than 700,000 facilities ) are of the conventional type passive thermosyphon. This type of installation has good performance and the simplicity of operation. Considering that approximately 8% of energy consumed in our country is for heating domestic water, this is an excellent alternative of ecological energy saving. In periods of low insolation, the user can rely on an auxiliary heating through a resistor installed inside the tank (boiler), powered through a circuit breaker. In this situation, with no one monitoring , the water temperature rises until it reaches the value of shutting down the thermostat's security system, which in most cases is set at 55 ° C. Without the monitoring of temperature, the system enters a regime of operation of successive periods of heating and cooling (for heat loss), until the user remember to turn off the breaker. This paper presents an economically viable solution to improve that, by making use of electronics microcontroller. Thus, one can monitor the water heating aid through the resistor sensor NTC, providing savings of up to 25% on the monthly bill, and other amenities. With three modes of operation: timer (operates as a timer), thermostat (panel adjustable thermostat ) and programmed (the user determines the time of use and temperature of the water), the system consists of the control console and power unit. The system is easy to install, providing a viable alternative to significantly improve the performance of current systems / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

The ability to predict the future behavior of solar activity has become of extreme importance due to its effect on the near-Earth environment. Predictions of both the amplitude and timing of the next solar cycle will assist in estimating the various consequences of Space Weather. Several prediction techniques have been applied and have achieved varying degrees of success in the domain of solar activity prediction. These techniques include, for example, neural networks and geomagnetic precursor methods. In this thesis, various neural network based models were developed and the model considered to be optimum was used to estimate the shape and timing of solar cycle 24. Given the recent success of the geomagnetic precusrsor methods, geomagnetic activity as measured by the aa index is considered among the main inputs to the neural network model. The neural network model developed is also provided with the time input parameters defining the year and the month of a particular solar cycle, in order to characterise the temporal behaviour of sunspot number as observed during the last 10 solar cycles. The structure of input-output patterns to the neural network is constructed in such a way that the network learns the relationship between the aa index values of a particular cycle, and the sunspot number values of the following cycle. Assuming January 2008 as the minimum preceding solar cycle 24, the shape and amplitude of solar cycle 24 is estimated in terms of monthly mean and smoothed monthly sunspot number. This new prediction model estimates an average solar cycle 24, with the maximum occurring around June 2012 [± 11 months], with a smoothed monthly maximum sunspot number of 121 ± 9.

Le développement de nouveaux matériaux pour les absorbeurs sélectifs pour le solaire thermique à concentration est une étape importante dans le déploiement des énergies renouvelables. La température actuelle de fonctionnement de ces absorbeurs (autour de 450°C) doit être augmentée jusqu’à 650°C ou plus, pour rendre cette technologie rentable. Dans ce but, de nouveaux matériaux pour les absorbeurs solaires doivent être développés, pour résister à ces températures sur le long terme, sans dégradation de leurs propriétés d’absorption. Les matériaux composites en couches minces sont des alternatives prometteuses aux matériaux existants, particulièrement les multicouches platine-alumine qui présentent une grande résistance en température et à l’oxydation. Le sujet de cette thèse a pour but de développer un matériau présentant une bonne absorption de l’énergie solaire et d’étudier les mécanismes de vieillissement qui interviennent dans ce matériau à haute température (650°C) sous air. Pour cela, nous nous sommes donc intéressés aux composites de platine et d’alumine. L’utilisation de simulations numériques a permis de développer une structure dont les propriétés optiques ont été optimisées. Ces structures ont ensuite été réalisées par pulvérisation cathodique magnétron et leurs propriétés optiques mesurées pour vérifier la sélectivité des absorbeurs obtenus. Des valeurs d’absorption de α=0.95 et d’émissivité de ε=0.18 ont été obtenues. Par la suite, notre étude a porté sur les différents mécanismes qui interviennent lors du vieillissement, notamment l’impact du substrat, et les parades pouvant être mises en place pour ralentir ce vieillissement. / Developing new absorber material for solar thermal power is a key step in the enhancement of renewable energies. The current working temperature of the absorber in power plant is too low (450°C) and must be raised to at least 650°C to enhance the yield of the plant. New absorber materials must be developed, to resist such high temperatures for many years, without losing their optical selectivity. Multilayer composite materials show promising results, especially platinum-alumina multilayer because of their good thermal stability. The aim of this PhD was to develop an absorber presenting a good solar absorption and to study the degradation mechanisms taking place during the aging at 650°C in air. Therefore, we studied the platinum-alumina multilayer. We used optical simulation to optimize the structure of our absorber. Then we realized these structures by magnetron sputtering and we performed optical characterizations to verify the optical selectivity. Values of absorption and emissivity of α=0.95 and ε=0.18 were obtained. At that point, we performed aging tests on our absorbers to study the degradation mechanisms taking place during aging at 650°C and to find ways to avoid those degradations in future applications.

Solar heat pump systems (SHPs) are systems that combine solar energy and heat pumps. SHPs have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many solar thermal heat pump systems have become market-available in recent years; however these systems are still not widely employed in the residential sector. This is due mainly to the high initial costs (investment and installation costs) of solar thermal heat pump systems, which limits their cost-effectiveness. Enhancing cost-effectiveness of solar thermal heat pump systems is necessary for a more effective and broader market penetration. In this thesis, solar thermal and photovoltaic systems combined with heat pumps for heating applications are treated. The overall aims of the thesis are to: 1) investigate techno-economics of SHPs and 2) investigate possible solutions for improving system performance of a reference solar thermal and heat pump system for residential heating applications. In the first part of the thesis, the influence of climatic boundary conditions on economic performance of SHPs has been investigated by means of: a) an economic comparison of SHPs found in the relevant literature and b) system simulations of the reference solar thermal heat pump system. In the second part of the thesis, potential solutions for improving system performance of the reference solar thermal heat pump system with limited change in system’ costs are investigated. A systematic approach was used for investigating cost-effectiveness of the system improvements in the reference system. Based on results of the cost-effectiveness analysis, some of the investigated system improvements were chosen for being included in the design of a novel solar thermal and air source heat pump system concept. The novel system was designed for a house standard with relatively high operating temperatures (55°C/45°C) in the space heating distribution system and for high space heating demand (123 kWh/m2·year). Finally, the thesis ends with a cost-effectiveness analysis of the novel system. / <p>QC 20170918</p> / MacSheep / iNSPiRe

M.Ing. / A dissertation presented on the basic solar design principles such as sun-earth geometry, energy wavelengths, optics, incidence angles, parabolic collector configurations and design, materials for solar applications, efficiencies, etc to be considered in Solar Concentrating Collector design. These principles were applied in the design and fabrication of a prototype solar collector. The solar collector was tested to verify and correct mathematical models that were generated from existing literature; as well as for optimization work.