Increased standards of living and indoor comfort demands have led to an increase in the demand for air-conditioning in buildings in South Africa. Conventional vapor compression systems use refrigerants that damage the ozone layer and contribute significantly to the global warming effect. Therefore, there is an urgent need to implement environmentally cleaner ways of satisfying this air-conditioning demand and absorption cooling systems have shown great potential to do so. This project is concerned with finding the technical and economic effectiveness of solar powered absorption cooling systems for South African climatic conditions. Solar cooling systems are made up of a solar collector array, water storage tank, absorption chiller and cooling tower for heat rejection. In this study, two complete systems, one utilizing an open wet cooling tower and another using a dry cooler were studied and their technical and economical performance analyzed. One system was installed at Netcare Moot Hospital in Pretoria and comprised of a solar collector array made up of 52 evacuated tube collectors, two 6000 litre hot water storage tanks, 35kW LiBr-water absorption chiller, and a wet cooling tower. This system was coupled to an existing vapor compression chiller so that cooling is provided even when no solar energy is available. The installation controlled and remotely monitored through the internet and parameters logged through a Carel Building Management System. The other system is at Vodacom World in Midrand, Johannesburg and is an autonomous solar heating and cooling system aimed at maintaining the building environment at comfort conditions throughout the year. It is made up of a 116m2 evacuated tube collector array, a 6500litre hot water storage tank, 35kW LiBr-Water absorption chiller, 1m3 of cold water storage, a dry cooler for the chiller, and two underground rock storages to pre-cool the supply air to the building and the dry cooler respectively. Long term system performance studies were carried out by varying the system control strategy for the chiller, hot water storage tank, existing vapor compression chiller (in the case of the Moot Hospital installation), hot water storage tank, dry cooler (for the Vodacom installation) and the system Coefficient of Performances were calculated and life cycle cost analysis carried out. Due to the fact that solar availability and cooling demand are approximately in phase, solar powered absorption cooling presents a great opportunity for reducing peak electrical cooling energy demand. It was also discovered that the economic effectiveness of the system increases with the absorption chiller capacity, and it‟s more advisable to operate the solar absorption cooling system with a vapor compression chiller as a backup for facilities that require uninterrupted cooling. The solar autonomous system is oversized for most of the year since it is designed to cover the peak cooling loads. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.

Thesis (M.E. Mechanical Engineering)--University of Waikato, 2007. / Title from PDF cover (viewed May 6, 2008) Includes bibliographical references (p. 102-108)

Neste trabalho é apresentado o desenvolvimento de um programa computacional que simula o desempenho térmico de um sistema de aquecimento solar de água com circulação forçada, adequado para uso em edificações. O programa trabalha realizando o balanço de massa e de energia no reservatório térmico a cada hora, tendo como valores de entrada dados do ano meteorológico típico da localidade selecionada e a vazão de água quente de consumo. Os componentes do sistema são o reservatório térmico de água quente com aquecedor auxiliar interno, o coletor solar e a bomba de circulação. A base de dados meteorológicos escolhida foi a do projeto SWERA, que contém arquivos no formato padrão TMY disponíveis na internet para um número considerável de cidades, incluindo diversas localidades brasileiras. Foi proposto um modelo de temperatura de água da rede de abastecimento relacionado com a temperatura do solo, dado disponível nos arquivos de entrada utilizados. O programa utilizou como referência para a validação dos modelos de cálculo resultados obtidos pelo programa comercial de simulação TRNSYS. Foram comparados resultados para os modelos de irradiação incidente em superfície inclinada, do coletor solar e do sistema completo. Para isto foram simulados sistemas localizados em quatro cidades distintas com climas diferentes. O tempo total usado nas simulações foi de um ano e os resultados das comparações dos valores resultantes foram considerados satisfatórios. / This paper presents the development of a software that simulates the thermal performance of a solar water heating system with forced circulation, suitable for buildings. The implemented model computes the mass and energy balance in the thermal tank every hour. Its input data are values from a typical meteorological year of a chosen location and the hot water load. The system components are the thermal tank, the solar collector and the circulation pump. The Swera project was used as the meteorological database, which contains files in the standard TMY format. Those are available on the internet for a number of cities, including several Brazilian locations. A model for the network water supply temperature was proposed. It is related with the ground temperature, available in the data input files. The validation of the models used results obtained by the commercial simulation software TRNSYS. Results for the incident radiation on tilted surface, the solar collector and the complete system models were compared. For that, systems were simulated in four cities with different climates. The total time used in the simulations was one year and the results obtained from this comparison were satisfactory.

Thesis (DTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016. / The water desalination process needs large quantities of energy, either directly from fossil fuel or electricity from the national grid. However, these sources of energy significantly contribute to problems such as global warming in addition to creating a drain on the economy, due to their high cost. This dissertation is a description of the research undertaken with the aim of producing a water desalination prototype; a novel approach that was designed using state-of-the-art solar water heating equipment, incorporating the technologies of evacuated tubes and heat pipes. During the execution of the project, various modifications to the original commercially-available solar water heating system were attempted, each aimed at increasing the production of pure water. Finally, the system proved capable of producing a reasonable amount of pure water after twelve lengthy indoor experiments conducted in a laboratory in the department of Mechanical Engineering at the Cape Peninsula University of Technology, Bellville Campus, Cape Town, South Africa. Each experiment lasted five days on the basis of seven hours of exposure to an average amount of simulated solar radiation, followed by seventeen hours daily of inactivity and partial cooling down of the system.

Thesis (DTech (Engineering))--Cape Peninsula University of Technology, 2017. / The world has been experiencing energy-related problems following pressuring energy demands which go along with the global economy growth. These problems can be phrased in three paradoxical statements: Firstly, in spite of a massive and costless solar energy, global unprecedented energy crisis has prevailed, resulting in skyrocketing costs. Secondly, though the sun releases a clean energy, yet conventional plants are mainly being run on unclean energy sources despite their part in the climate changes and global warming. Thirdly, while a negligible percentage of the solar energy is used for power generation purposes, it is not optimally exploited since more than its half is wasted in the form of heat which contributes to lowering efficiency of solar cells and causes their premature degradation and anticipated ageing. The research is geared at addressing the issue related to unsatisfactory efficiencies and anticipated ageing of solar modules. The methodology adopted to achieve the research aim consisted of a literature survey which in turn inspired the devising of a high-efficiency novel thermal electric solar power panel. Through an in-depth overview, the literature survey outlined the rationale of the research interest, factors affecting the performance of PVs as well as existing strategies towards addressing spotted shortcomings. While photovoltaic (PV) panels could be identified as the most reliable platform for sunlight-to-electricity conversion, they exhibit a shortcoming in terms of following the sun so as to maximize exposure to sunlight which negatively affects PVs’ efficiencies in one hand. On the other hand, the inability of solar cells to reflect the unusable heat energy present in the sunlight poses as a lifespan threat. Strategies and techniques in place to track the sun and keep PVs in nominal operational temperatures were therefore reviewed.

Neste trabalho é apresentado o desenvolvimento de um programa computacional que simula o desempenho térmico de um sistema de aquecimento solar de água com circulação forçada, adequado para uso em edificações. O programa trabalha realizando o balanço de massa e de energia no reservatório térmico a cada hora, tendo como valores de entrada dados do ano meteorológico típico da localidade selecionada e a vazão de água quente de consumo. Os componentes do sistema são o reservatório térmico de água quente com aquecedor auxiliar interno, o coletor solar e a bomba de circulação. A base de dados meteorológicos escolhida foi a do projeto SWERA, que contém arquivos no formato padrão TMY disponíveis na internet para um número considerável de cidades, incluindo diversas localidades brasileiras. Foi proposto um modelo de temperatura de água da rede de abastecimento relacionado com a temperatura do solo, dado disponível nos arquivos de entrada utilizados. O programa utilizou como referência para a validação dos modelos de cálculo resultados obtidos pelo programa comercial de simulação TRNSYS. Foram comparados resultados para os modelos de irradiação incidente em superfície inclinada, do coletor solar e do sistema completo. Para isto foram simulados sistemas localizados em quatro cidades distintas com climas diferentes. O tempo total usado nas simulações foi de um ano e os resultados das comparações dos valores resultantes foram considerados satisfatórios. / This paper presents the development of a software that simulates the thermal performance of a solar water heating system with forced circulation, suitable for buildings. The implemented model computes the mass and energy balance in the thermal tank every hour. Its input data are values from a typical meteorological year of a chosen location and the hot water load. The system components are the thermal tank, the solar collector and the circulation pump. The Swera project was used as the meteorological database, which contains files in the standard TMY format. Those are available on the internet for a number of cities, including several Brazilian locations. A model for the network water supply temperature was proposed. It is related with the ground temperature, available in the data input files. The validation of the models used results obtained by the commercial simulation software TRNSYS. Results for the incident radiation on tilted surface, the solar collector and the complete system models were compared. For that, systems were simulated in four cities with different climates. The total time used in the simulations was one year and the results obtained from this comparison were satisfactory.

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

Orientador: Ennio Peres da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T02:08:03Z (GMT). No. of bitstreams: 1 Castro_RodolfoDamasiode_M.pdf: 3152478 bytes, checksum: a4e0e80e4ac1f8804a7b3aa8589139b4 (MD5) Previous issue date: 2015 / Resumo: A busca por meios de geração de energia para atender às necessidades humanas com menores impactos sociais e ambientais é constante. A geração de energia elétrica por meio de fontes renováveis na forma distribuída, ou não centralizada, é um meio ou método de minimizar tais impactos. O objetivo da pesquisa foi analisar a viabilidade econômica, frente a tarifa de energia elétrica das concessionárias locais, da utilização de sistemas de geração solar em residências brasileiras situadas nas capitais dos estados, na capital federal, Brasília e na cidade de Campinas (SP). Diferentes situações de dimensionamento foram utilizadas para dois tipos de sistemas: um sistema fotovoltaico puro, para atender toda a necessidade energética da residência, incluindo o chuveiro elétrico, e um sistema solar híbrido, composto por aquecimento solar para atender a demanda por água quente no banho em conjunto com geração fotovoltaica para atender as necessidades em equipamentos elétricos. As situações de dimensionamento utilizadas foram três, onde em cada uma o sistema fotovoltaico foi projetado para uma determinada produção de energia. Os sistemas fotovoltaico e de aquecimento solar foram dimensionados com o auxílio dos softwares PVSyst e Dimensol, respectivamente. O custo total dos sistemas foi estimado a partir de pesquisa em lojas com endereço eletrônico na rede de computadores e de orçamentos fornecidos por empresas do ramo. Determinou-se o preço final da energia elétrica convencional para todas as cidades a partir da tarifa definida pela ANEEL, do valor médio do PIS efetivo cobrado pelas concessionárias e da alíquota de ICMS que os governos estaduais recolhem. Após realizados os cálculos, chegou-se ao resultado de que somente nas cidades de Macapá (AP) e Boa Vista (RR), devido principalmente ao baixo custo das tarifas de energia elétrica, o usuário não economizaria com a instalação dos sistemas. Porém, em cidades de elevada tarifa, como Belém (PA) e Belo Horizonte (MG), o usuário pagaria cerca de R$ 0,30 por quilowatt hora consumido a menos / Abstract: The search for power generation means to meet human needs with lower social and environmental impacts is constant. The distributed generation of electricity by renewable energies is a method to minimize those impacts. The research aimed to analyze the economic viability against local electricity tariff of the use of solar power generation systems in Brazilian households located in the capitals of the states, in the federal capital, Brasilia, and in the city of Campinas (SP) Different sizing situations were used for two types of systems: a pure PV system to meet all the energy needs of the residence, including electric shower, and a hybrid solar system, consisting of solar heating to meet the demand for hot water in the bath together with photovoltaic generation to meet the needs in electrical equipment. Sizing situations used were three, where in each one the PV system is designed for a certain production of energy. The photovoltaic systems and solar heating were sized with the help of the softwares PVSyst and Dimensol, respectively. The total cost of the systems was estimated by a research in webstores and budgets provided by companies in the field. Was determined the final price of conventional electricity to all cities from the tariff set by ANEEL, the average value of the effective PIS charged by concessionaires and ICMS aliquot that state governments collect. After performing the calculations, came to the result that only the cities of Macapa (AP) and Boa Vista (RR), mainly due to the low cost of electricity tariffs, the user does not save due to the installation of the systems. However, in cities of high tariff, as Belém (PA) and Belo Horizonte (MG), the user would save about R$ 0.30 per quilowatt-hour / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Planejamento de Sistemas Energéticos

The master´s thesis deals with the design of the solar heating regulator of the swimming pool. The basis was to study the available solutions for the solar pool controllers, to define the requirements, to design the concept and the block diagram of the own thermostat. The thesis also provides a description of several for the Internet of Things. The most suitable is used to control the thermostat. The resulting thermostat regulates two power outputs for filtration and the pump, it can be set using the keyboard and graphic display. At the end of the work is practically verified functionality on the model and on the real pool with solar heating.

京都大学 / 0048 / 新制・論文博士 / 博士(工学) / 乙第12983号 / 論工博第4130号 / 新制||工||1637(附属図書館) / 32453 / 台湾国立成功大学大学院工学研究科建築学専攻 / (主査)教授 鉾井 修一, 教授 原田 和典, 教授 神吉 紀世子 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM