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‣ Aquecimento solar de água: metodologia de avaliação da incerteza na medição do desempenho térmico de coletores solares planos utilizando simulador artificial de radiação solar.; Solar water heating: methodology for uncertainty evaluation of solar thermal collectors performance using a solar simulator.

Sowmy, Daniel Setrak
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/08/2013 Português
Relevância na Pesquisa
617.7104%
Este trabalho apresenta uma metodologia de avaliação da incerteza associada à medição do desempenho térmico de coletores solares térmicos, utilizados em aquecedores de água residenciais. A determinação desta grandeza tem influência direta na estimativa da fração solar obtida pelo sistema, e consequentemente no tempo de retorno sobre o investimento do mesmo. Coletores solares planos, construídos a partir de perfis de alumínio, com absorvedores metálicos, pintura preta não seletiva, tubulação interna de cobre, cobertura de vidro simples e isolante térmico na parte traseira, foram ensaiados individualmente em laboratório para determinação do seu desempenho. O procedimento adotado foi o indoor, onde os ensaios são realizados sob um simulador artificial de radiação solar, e envolveu a configuração da câmara de testes, estabilização das variáveis ambientais, ensaios das amostras, cálculo do desempenho térmico e estimativa da sua incerteza associada. Esta última levou em consideração as contribuições da instrumentação empregada, da estabilidade temporal das condições de contorno para realização das medições e do método estatístico utilizado na determinação da curva de desempenho térmico do coletor. Ao final do estudo foram ponderados os limites aceitos pelo programa de etiquetagem brasileiro de coletores em comparação com os resultados obtidos.; This work presents a methodology for assessing the thermal performance uncertainty of solar collectors used in residential water heaters. The uncertainty has a direct influence on the solar fraction prediction and consequently on its payback time. Flat solar collectors...

‣ Análise exergética e termoeconômica de um sistema solar termodinâmico de aquecimento de água; Exergetic and thermoeconomic analysis of a solar heat-pump system for water heating

Silva, Yuri Cambrussi da
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf
Português
Relevância na Pesquisa
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Este trabalho avalia e propõe melhorias a um sistema solar termodinâmico de aquecimento de água, que consiste em uma bomba de calor na qual o evaporador é um painel solar e o condensador é um trocador de calor utilizado para aquecer água. Para otimizar o sistema, são realizadas análises teóricas de exergia e termoeconomia de um aquecedor fabricado no Brasil pela Solary – Aquecedores Termodinâmicos. Na resolução das equações decorrentes dessas análises e obtenção das propriedades termodinâmicas do refrigerante R134a utiliza-se do programa Interactive Thermodynamics. Os resultados indicam uma eficiência exergética de 12% e custo total (incluindo aquisição do equipamento) de R$ 0,7170 por hora de funcionamento. Duas propostas de melhoria são analisadas: aumento do rendimento isentrópico do compressor e aumento da temperatura do evaporador. Esta última apresenta os melhores resultados, atingindo um rendimento de 17% e custo total de R$ 0,6383 por hora.; This study evaluates and proposes improvements to a thermodynamic solar water heater, that consists of a heat-pump in which the evaporator is a solar panel and the condenser is a heat exchanger used to heat water. To optimize the system, theoretical analysis of exergy and thermoeconomics of a heater produced in Brazil by Solary – Thermodynamic Heaters are performed. In the solution of the equations resulting from these analyses and obtain the thermodynamic properties of the R134a refrigerant...

‣ Análise dos parâmetros técnicos e econômicos do aquecedor solar a vácuo, visando economia de energia

Gonçalves, Janaína Domingues
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Trabalho de Conclusão de Curso Formato: 100 f.
Português
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This work is about a development of a vacuum solar water heater. To accomplish this, some measurements were made, such as flow, water temperature and room temperature, relative humidity, solar power density and wind speed. It first presents a brief explanation about the global situation in relation to the accelerated use of exhaustible energy sources which can result in a breakdown of these for future generations. From this, is proposed to analyze this solar water heater with vacuum tubes during the winter season in Brazil southeastern region, under different environmental conditions. From such ideas became possible to prove through the experimental part, calculations and graphical results that technology and the performance of this device are technical and economically viable, according to the life cycle of this. It was also found that the average monthly production in a maximum heat stroke situation was 193,33kWh and minimum isolation was 57,76kWh. This reveals that this instrument should start to be examined more closely by all, as a way to reduce the use of electricity, which will protect the environment without reducing the comfort of people; Neste trabalho desenvolveu-se o estudo de um aquecedor solar a vácuo. Para tal, realizaram-se medidas de vazão...

‣ Sintese otimizada de sistemas de aquecimento solar de agua

Thomaz P. de Freitas Borges
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/01/2000 Português
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Considera-se o dimensionamento otimizado de um sistema de aquecimento solar de água como o conjunto de valores para as diversas variáveis de projeto (área de placa coletora, volume de reservatório térmico, e outras) que resulta no mínimo custo ao longo da vida útil do equipamento. Este custo deve levar em conta diversos gastos, como os de aquisição, manutenção e despesas com uso de energia auxiliar. Neste trabalho, desenvolveu-se um procedimento computacional que encontra este dimensionamento otimizado, em face a condições climáticas específicas do local de instalação, condições de uso de água quente, e demais condições de projeto. Para isso, acoplou-se um procedimento de otimização não-linear a uma rotina de simulação numérica a longo prazo em regime transiente. O procedimento utiliza o método dos Gradientes Conjugados. Foi feito o estudo de caso do projeto de um sistema de aquecimento solar de água tennossifão com placas planas para o clima de Campinas-SP. A função objetivo a ser minimizada é o valor anual das despesas totais (custos fixos e custos variáveis) de se produzir água quente, calculados em uma análise de ciclo de vida econômico. Executando este procedimento para um problema de apenas dois parâmetros...

‣ Indústria solar térmica em Cabo Verde : potencialidade do mercado

Nascimento, Cláusia Maria Fonseca da Rocha
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
Português
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O presente trabalho pretende fazer uma análise do potencial do mercado Cabo-verdiano para a utilização da energia solar, através de algumas ferramentas de análise de mercado já conhecidas, nomeadamente as cinco forças de Porter, o Diamante de Porter, a análise PESTEL e a análise SWOT. O primeiro ponto que se pretende esclarecer é a questão: Será que Cabo Verde reúne as condições para ser considerado uma potencial mercado para a produção/ venda de sistemas solares para o aquecimento da água? O segundo ponto seria o de se determinar que tipo de actividade seria mais viável ser desenvolvida, tendo em conta os padrões do país: Produção dos sistemas solares dentro do país através da instalação de fábricas ou a comercialização de sistemas solares importados. Por último, pretende-se a definição do consumidor alvo bem como a caracterização do tipo de sistema solar a ser comercializado no país. ABSTRACT: This essay has been performed in order to analyze the solar water heater industry market potential in Cape Verde, using some known tools for market analysis like the Porter’s Five Forces, the National Diamond, the PESTLE analysis and the SWOT analysis. T he first point I intend to make clear is the question: Has Cape Verde the conditions to be considered a potential market to produce/ sell solar water heaters? The second one concerns about determining what kind of activity would be viable to be developed according the patterns of the country: The production of solar systems inside the country through the installation of factories or just the commercialization of imported solar systems. Finally...

‣ Estudo de desempenho do aquecedor solar de baixo custo

Siqueira, Débora Abrahão
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Dissertação
Português
Relevância na Pesquisa
664.6336%
Uma das alternativas para diminuir o consumo de energia elétrica para aquecimento de água será popularizar o uso da energia solar. Este trabalho vem a contribuir com estudos sobre o Aquecedor Solar de Baixo Custo, ASBC, que é um novo conceito de aquecedor solar de água para residência, todo feito de materiais poliméricos, com investimento relativamente pequeno e que pode ser construído manualmente. A placa do coletor, que absorve a energia solar e a transfere para a água na forma de calor, é formada por perfis planos de PVC rígido e sem cobertura. Outra opção de coletor solar que foi utilizada é a placa de polipropileno, que é um material com aditivo anti-UV, que assim como a placa de PVC teve seu desempenho térmico analisado neste trabalho. O reservatório térmico de cada um dos dois coletores é de polietileno revestido por isopor, responsável por armazenar a água aquecida durante o dia. Ambos os sistemas de aquecimento tiveram seus resultados comparados com o aquecedor convencional, formado por coletor de cobre recoberto por uma cobertura de vidro e um reservatório de aço inox. Uma bancada de ensaios para os coletores solares e reservatórios foi montada no Campus da UFU, avaliando a eficiência dos três sistemas com medidas de radiação solar incidente e de temperatura da água...

‣ Active control of split system domestic solar water heaters

Dennis, Michael Kenneth
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (PhD); Doctor of Philosophy (PhD)
Português
Relevância na Pesquisa
544.89426%
Solar water heaters have the potential to make large savings in greenhouse gas emissions in Australia. Long financial payback periods are the main reason that uptake of solar water heating is not more significant. This thesis investigates the potential improvement in performance of split-system solar water heaters by the addition of an active control system. This work builds upon "low flow" collector circulation theory and addresses the poor control available from the storage tank thermostat. Modelling suggests that the thermal efficiency of the water heater can be improved by about 25°/o, primarily through reduction of tank standing losses, if the thermostat is replaced by a smart controller. Auxiliary energy consumption is reduced proportionally. If realisable, these savings recover the capital cost of the additional controller in several years. The consumer will benefit from further savings in auxiliary energy consumption over the life of the system and so the payback will be more attractive. The active control strategy is based upon predicting and controlling the energy content of the storage tank. The control strategy is energy tariff sensitive and may be set by the householder to behave in an energy efficient or a cost effective manner. A number of technologies and design improvements regarding forecasting of the energy supply and demand were also developed in this work. The auxiliary heater was moved outside of the tank and placed in series with the solar collector via a switching valve arrangement. The collector circulation pump was also used to circulate water through the auxiliary heater effectively providing a variable volume...

‣ Renewable Energy Desalination : An Emerging Solution to Close the Water Gap in the Middle East and North Africa

World Bank
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
Português
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616.43184%
The Middle East and North Africa (MENA) region is one of the most water-stressed parts of the world. In just over 25 years, between 1975 and 2001. Looking to the future, MENA's freshwater outlook is expected to worsen because of continued population growth and projected climate change impacts. The region's population is on the way to doubling to 700 million by 2050. Projections of climate change and variability impacts on the region's water availability are highly uncertain, but they are expected to be largely negative. To offer just one more example, rainfall and freshwater availability could decrease by up to 40 percent for some MENA countries by the end of this century. The urgent challenge is how to adapt to the future as illustrated by these numbers and how to turn the region's economy onto a sustainable path. This volume suggests new ways of thinking about the complex changes and planning needed to achieve this. New thinking will mean making better use of desert land, sun, and salt water the abundant riches of the region which can be harnessed to underpin sustainable growth. More mundane...

‣ Performance Analysis of a Transcritical CO2 Heat Pump Water Heater Incorporating a Brazed-Plate Gas-cooler

Murray, PORTIA
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
613.6124%
This study focuses on the experimental testing and numerical modeling of a 4.5 kW transcritical CO2 heat pump water heater at Queen’s University in the Solar Calorimetry Laboratory. Due to the predicted high heat rejection temperatures in a transcritical vapour-compression cycle, buoyancy driven thermosyphon flow through a brazed-plate gas-cooler was proposed to promote tank stratification and to improve system performance. The performance was evaluated through a series of experimental sensitivity and static tank charge tests. A TRNSYS model was also created and verified to simulate the performance of the system under a detailed user demand schedule for a week of operation. The TRNSYS model used a parametric table created with a steady-state model of the vapour-compression system in EES that was validated against experimental data to a standard error of the Y-estimate of ±0.073 kW for heating capacity, ±1.01°C for gas-cooler exit temperature, and ±0.086 for COP. A series of tank charge tests were conducted under thermosyphon flow and forced flow rates at 1 L/min, 2 L/min, and 4 L/min. The thermosyphon charge test produced the highest level of stratification and a total COP of 3 at an average flow rate of 0.73 L/min. All of the forced convection cases operated with a higher degree of mixing. TRNSYS model simulations with hot water draws found that the thermosyphon flow configuration performed with a higher degree of stratification under regular user demand while simulations with high flow rates resulted in a mixed tank at a high temperature. Results predicted an 11% reduction in required heat energy input to the storage...

‣ Estudo de um sistema híbrido de destilação solar para polimento de águas produzidas

Ramos, Rafael Eugênio Moura
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Química; Pesquisa e Desenvolvimento de Tecnologias Regionais Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Química; Pesquisa e Desenvolvimento de Tecnologias Regionais
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
550.5537%
The oil industry, experiencing a great economic and environmental impact, has increasingly invested in researches aiming a more satisfactory treatment of its largest effluent, i.e., produced water. These are mostly discarded at sea, without reuse and after a basic treatment. Such effluent contains a range of organic compounds with high toxicity and are difficult to remove, such as polycyclic aromatic hydrocarbons, salts, heavy metals, etc.. The main objective of this work was to study the solar distillation of produced water pre-treated to remove salts and other contaminants trough of a hybrid system with a pre-heater. This developed apparatus was called solar system, which consists of a solar heater and a conventional distillation solar still. The first device consisted of a water tank, a solar flat plate collector and a thermal reservoir. The solar distillator is of simple effect, with 1m2 of flat area and 20° of inclination. This dissertation was divided in five steps: measurements in the solar system, i.e. temperatures and distillate flow rate and weather data; modeling and simulation of the system; study of vapor-liquid equilibrium of the synthetic wastewater by the aqueous solution of p-xylene; physical and chemical analyses of samples of the feed...

‣ Tecnologia solar residencial : inserção de aquecedores solares de agua no Distrito de Barão Geraldo - Campinas; Residential solar technology : insertion of solar water heaters in Barão Geraldo, district of Campinas

Fabiana Karla de Oliveira Martins Varella
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/07/2004 Português
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O mercado de aquecimento solar de água vem crescendo desde a década de 90, porém há falta de informações sobre estudos de caso que avaliem a inserção de aquecedores solares de água nos domicílios brasileiros. Visando contribuir para reduzir essa carência o presente trabalho tem como objetivo avaliar a inserção de aquecedores solares de água no distrito de Barão Geraldo, Campinas-SP. A avaliação foi efetuada através de um plano amostral aleatório estratificado, pois essa metodologia permite conhecer melhor as características próprias de cada segmento da região estudada. Foi necessária a construção de um cadastro para a população pertencente ao distrito de Barão Geraldo, a realização de uma amostra piloto, e por fim, uma amostra final. Após a elaboração do cadastro foram desenvolvidos três questionários para revendedores autorizados, fabricantes e consumidores. O resultado dos questionários aplicados aos consumidores mostra que 19% (com margem de erro máximo de ±5%) dos domicílios do distrito de Barão Geraldo possuem aquecedor solar, ou seja, 1.800 domicílios. Foi realizada a análise do perfil de consumo de energia elétrica dos domicílios por posse de aquecedor solar de água, no período de 1999 a 2003. Verificou-se que os domicílios com aquecedor solar estão consumindo mais energia elétrica do que aqueles que não o tem. Porém...

‣ Techno-Economic Analysis of Solar Water Heating Systems in Turkey

Ertekin, Can; Kulcu, Recep; Evrendilek, Fatih
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 25/02/2008 Português
Relevância na Pesquisa
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In this study, solar water heater was investigated using meteorological and geographical data of 129 sites over Turkey. Three different collector types were compared in terms of absorber material (copper, galvanized sheet and selective absorber). Energy requirement for water heating, collector performances, and economical indicators were calculated with formulations using observed data. Results showed that selective absorbers were most appropriate in terms of coverage rate of energy requirement for water-heating all over Turkey. The prices of selective, copper and galvanized absorber type's heating systems in Turkey were 740.49, 615.69 and 490.89 USD, respectively. While payback periods (PBPs) of the galvanized absorber were lower, net present values (NPVs) of the selective absorber were higher than the rest. Copper absorber type collectors did not appear to be appropriate based on economical indicators.

‣ Aquecimento solar de água : desempenho e racionalização de materiais e energia alternativa fundamental para o desenvolvimento sustentável

Georgi, Aurea Lúcia Vendramin
Fonte: Universidade Federal do Paraná Publicador: Universidade Federal do Paraná
Tipo: Tese de Doutorado Formato: 135 p. : il. algumas color.; application/pdf
Português
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Orientador: Prof. Dr. Carlos Itsuo Yamamoto; Co-orientador: Prof. Dr. Carlos Eduardo Camargo Nogueira; Tese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia e Ciência dos Materiais - PIPE. Defesa: Curitiba, 26/06/2015; Inclui referências : p. 129-135; Área de concentração: Engenharia e ciência de materiais; Resumo: Este trabalho teve como objetivo avaliar a eficiência energética e o custo benefício de um sistema de aquecimento solar de água - SWHS, com 1,00 m2 de coletor solar plano - FPC instalado na Casa Inteligente - campus Unioeste, cidade de Cascavel - PR, o estudo contempla benefícios e avanços tecnológicos para eficiência energética e sustentabilidade, sem danos ao meio ambiente, empregando materiais como o polietileno expandido, tubos PVC, alumínio, vidro e mantas de isolamento térmico, mesclando-os com materiais de reuso para minimizar a perda de eficiência e ao mesmo tempo diminuir o seu custo de aquisição. O sistema foi testado ao longo de um ano e o coletor obteve temperatura máxima registada de fluido de saída de 69 °C, enquanto a temperatura máxima da água na parte inferior do reservatório de água quente foi de 57 °C. A eficiência média diária do coletor solar foi de 60...

‣ A Flat Solar Collector Built from Galvanized Steel Plate, Working by Thermosyphonic Flow, Optimized for Mexican Conditions

Marroquín de Jesús,Á.; Olivares-Ramírez,J.M.; Ramos-López,G.A.; Pless,R.C.
Fonte: Facultad de Ingeniería, UNAM Publicador: Facultad de Ingeniería, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2009 Português
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Design, construction, and testing of the thermal performance of a flat solar collector for domestic water heating are described. The absorbing plate is built from readily available materials: two sheets of galvanized steel, one of the channelled type, the other one flat, which are joined by electric welding. The absorber is connected to a 198-L thermotank, insulated with polyurethane foam. In terms of receiving surface, the prototype tested here has an area of 1.35 m², about 20% smaller than comparable copper-tube-based collectors offered in the market. Temperature measurements conducted over a 30-day period gave values which were a few degrees lower than the theoretically calculated water temperatures. Momentary thermal efficiency values between 35% and 77% were observed. The water temperature achieved in the tank at the end of the day aver ages 65°C in winter weather conditions in the central Mexican highland. This design of solar water heater is well suited to Mexican conditions, as it makes use of the high local intensity of the solar radiation, and as the channel shape of the ducts minimizes bursting during the rare occurrences of freezing temperatures in the region; it also has the advantage of being manufacturable at low cost from simple materials.

‣ Economic and environmental analysis of solar water heater utilisation in Gauteng Province, South Africa

Özdemir,Enver Doruk; Marathe,Sheetal Dattatraya; Tomaschek,Jan; Dobbins,Audrey; Eltrop,Ludger
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
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This paper focuses on the energy economics and environmental impacts of solar water heaters (SWH) in the Gauteng Province and compares the results with other technology options for residential water heating with regard to the different income groups. The critical energy situation in South Africa and the highly coal dependent energy generation demonstrates the need to shift to a more sustainable way of living. The residential sector proves to be an optimal starting point to implement new technologies, especially for water heating. The residential hot water demand calculation shows that the annual demand in Gauteng is about 188 million cubic meters. In order to satisfy this demand, different technologies are investigated in this paper, where SWHs lie in focus. Due to the vast income inequality in Gauteng, and also in South Africa, it is obvious that there cannot be one single optimal solution suitable to all households. Therefore, this paper focuses on the differentiation of the residential sector into income groups to show the divergence in warm water demand and the applicability of alternative technologies. In order to analyse appropriate solutions for all income groups, low-cost alternatives are also analysed. The economic analysis shows that although SWHs have higher investment costs than conventional technologies...

‣ Analysis of the performance profile of the NCERD thermosyphon solar water heater

Agbo,Solomon
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 Português
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The work reported here is the performance profile of a thermosyphon solar water heater developed by the National Centre for Energy Research and Development (NCERD), University of Nigeria, Nsukka. The performance evaluation was based on the mathematical models that describe the test system and some measured experimental data. The effect of some of the design and operating parameters that have been shown to affect the system's performance was investigated. The parameters considered included the number of glazing covers, glazing cover thickness, tube spacing and the nature of absorber plate material. The performance results indicate that the test system has a maximum average daily collector efficiency of 0.658 and a mean system temperature of 81°C. The efficiency of the collector drops to an average seasonal value of 0.54 with a negligible variation across the three climatic seasons was covered in the study. With a tube spacing not exceeding 10 cm, the performance of the system is optimized irrespective of the nature of the absorber plate material. We found that the number of glazing covers affects the top-loss coefficient of the system depending on the type of absorber plate used. Multiple glazing shows a negligible contribution especially for low temperature application. The glazing cover thickness does not affect the performance of the system significantly.

‣ What contribution does the installation of solar water heaters make towards the alleviation of energy poverty in South Africa?

Wlokas,Holle Linnea
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 Português
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The South African government has publicized plans to install one million solar water heaters in households throughout South Africa by the year 2014, with the goals of reducing strain on existing electricity resources, mitigating greenhouse gas emissions, creating employment and alleviating poverty. This paper examines two existing solar water heater installation projects with the aim of investigating the social contribution of the installation of solar water heaters in low-income households in South Africa. The Sustainable Urban Livelihoods approach (SULA) was adjusted to provide an analytical framework for the development of suitable indicators of social change in the context of renewable energies and energy poverty. Increases in household capital and the reduction of household vulnerability to shocks, stressors and seasonal variability as the result of solar water heater installation were investigated in projects in low-income housing developments in the cities of Cape Town and Port Elizabeth, South Africa. Data collected from paired household surveys (before and after installation) in over 600 households and qualitative information (Most Significant Change stories) show that the provision of a constant, cheap source of heated water contributed positively to the alleviation of energy poverty. Household capitals (categorised as Human...

‣ Dissemination of solar water heaters in South Africa

Chang,Keh-Chin; Lin,Wei-Min; Ross,Greg; Chung,Kung-Ming
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 Português
Relevância na Pesquisa
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Global concern over a looming energy crisis, water scarcity and man-made climate change are driving a huge demand for clean technologies, which focus on preserving the earth's resources. In South Africa, the economy is very energy-intensive with coal being the main national energy supply. In view of the growing depletion of fossil fuel, it is important for South Africa to adopt a more sustainable energy mix. This study examines the potential for widespread dissemination of solar water heaters (SWHs) in South Africa. Barriers and constraints to market expansion are analyzed to determine strategies for overcoming these barriers. It is found that payback period of a SWH is shorter than the life-span of the system itself, indicating that SWHs are economically viable even with low production cost of electricity and thus represent a profitable investment proposition for end users, manufacturers and distributors. However, the subsidy programs offered by the government of South Africa may not be sufficient to facilitate diffusion. This is attributed to the high initial capital cost of the system and low affordability of the majority of the South Africa population with low income. Alternative financing mechanisms are required.

‣ Thermodynamic analysis of a direct expansion solar assisted heat pump water heater

Yousefi,Masoud; Moradali,Misagh
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2015 Português
Relevância na Pesquisa
742.096%
In this paper, the thermodynamic performance of a direct expansion solar assisted heat pump (DX-SAHP), which is used to heat domestic water from 20°C to 45°C, is theoretically investigated. The system includes a 3m² single-cover flat plate solar collector, 0.150m³ water tank and 70m tube immersed in the water tank as a condenser. The effect of various parameters such as radiation on the collector surface, compressor speed and the ambient temperature on the coefficient of performance (COP) are calculated. Results show that obtained COP is considerably more than that of a conventional heat pump water heater when radiation on the collector is high. Also, increasing collector area and reducing compressor speed enhance COP. The same occurs when the ambient temperature increases. For instance, at an ambient temperature of 15°C and 450 w/m² irradiation on collector surface, the calculated COP was 6.37.

‣ Solar water heater contribution to energy savings in higher education institutions: Impact analysis

Popoola,Olawale M; Burnier,Clément
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 Português
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This paper focuses on the impact of Solar Water Heaters (SWH) at a higher institution of learning. An energy audit was conducted for the evaluation of the energy conservation measure: energy conoduction Energy is a key element in the development of any country or institution; as a result any shortage in energy will have a serious effect on the economy and social aspect of such country or institution. South Africa has, in recent years, experienced high economic growth as well as a rapid expansion in the elsumption analysis, correlation of consumption with weather; financial criteria, payback period and needed solar heater system (SWH) to determine the energy that may be termed as wastage or can be saved. The method of investigation includes assessment of the hot water usage within the institution campus and residencies, analysis of bills, metering and development of a software model for the analysis of energy use, system needed and environmental variables. This renewable measure (SWH) showed a high potential of energy and financial savings for higher education institutions especially those with residences