In this thesis, performance of a heat pump aided by solar heating system with an evacuated tubular collector has been analyzed theoretically and experimentally. For this purpose, a domestic hot water heating system has been designed, constructed and tested. The evacuated tubular solar collector has been used to achieve higher collector efficiency in winter. The fraction of the solar energy utilized has been measured experimentally and estimated theoretically. Effects of various parameters have been investigated on the performance of the proposed system. A mathematical model was developed to investigate the effects of different environmental, design and operational parameters on the solar heating system. In order to compare the obtained theoretical results with experimental ones, an experimental study has been carried out. For that, a number of experiments have been made at the solar house of the Mechanical Engineering Department of METU. An air-to-air heat pump was integrated with an evacuated tubular solar water heater unit (closed water circulation) and the performance of it has been studied experimentally. As a result of the experimental study, the maximum value of the coefficient of performance of the solar assisted heat pump used in this study was obtained as 4.85. The second law efficiency of the system was between 4.8-27.4 %.

This thesis investigates the possibility of using an unglazed flat-plate solar collector as a cooling radiator. The solar collector will be connected to the condenser of a heat pump and used as cooler during nighttime. Daytime the solar collector will be connected to the evaporator of the heat pump and used as heat source. The two widely differing fields of application make special demands on the solar collector. The task is given by the heat pump manufacturer Thermia and the main objective is to find out whether a solar collector should be used as a cooler or not. The performance of the solar collector under varying environmental conditions is investigated using COMSOL Multiphysics 3.3. Only the cooling properties are investigated here. The performance of the solar collector as a heat exchanger is estimated using the effectiveness-NTU method, and the solar collector is found to be a good heat exchanger at low wind speeds. The heat transfer coefficients of the convection and radiation are determined for varying temperature and wind speeds. The convective heat transfer coefficient is lowered by tubes above the absorber plate and for a high convective heat transfer rate the solar collector surface should be smooth. For a high radiative heat transfer rate the surface needs to have a high emissivity. The cooling rate is higher from a warm surface than from a cold and since no temperature change of the heat carrier is necessary the solar collector should be kept at a high temperature. To increase the cooling rate alterations need to be made to the solar collector that makes its heating performance deteriorate. A solar collector that can be used for cooling is not an efficient solar collector.

The Thesis analyzes one of the spheres of alternative energy supply – the solar energy. The main objective of the Thesis is to determine the energy rates of the solar collector and its accumulative capacity. The Paper introduces a stand on the solar collector research which consists of a flat solar collector, heat accumulator and auxiliary equipment. The research object of the Thesis is a laboratory flat solar collector and its system. The Thesis analyses the constructions of the solar collector which is meant for water heating. For this purpose theoretical research has been made, and experimental tests have been performed in a confined room by using a simulator of solar radiation and blowing the solar collector at an average wind speed of 2 m/s. Tests on the energy characteristics of the solar collector have been performed by using transparent poly-carbon covering and the glass covering; without using transparent covering and changing the debit of the heat-carrier. The author has made the reliance of the solar collector and accumulative capacity on the in-flowing and out-flowing heat-carrier and differences of the environment temperatures by using different coverings and debits of the heat-carrier. The relation between the accumulative capacity of the solar collector and the dimension of the solar collector has been established.

Baigiamajame magistro darbe atliktas eksperimentinis neįstiklinto pratakaus saulės kolektoriaus efektyvumo tyrimas. Eksperimento metu parinkta ir sumontuota matavimo ir duomenų kaupimo įranga. Pagal gautus meteorologinius ir kolektoriaus parametrų duomenis išanalizuotas kolektoriaus veikimas. Nustatyta kolektoriaus paviršiaus ir tiekiamojo oro temperatūrų, temperatūrinio efektyvumo ir bendro efektyvumo priklausomybė nuo išorinių veiksnių. Atliktas rezultatų palyginamas esant pastoviam ir kintamam tiekiamojo oro debitui, ir nustatyta jo įtaka kolektoriaus veikimui. Remiantis šilumos srauto principu ir naudojantis parinkta matavimo įranga, nustatyta kolektoriaus veikimo įtaka išorinei pastato atitvarai. Nustatyti galimi šilumos pritekiai šildymo sezono ir vasaros metu, naudojant kolektorių kaip apsauginę priemonę nuo tiesioginių saulės spindulių. Atliktas kolektoriaus ekonominis ir energinis vertinimas naudojantis RETScreen programa ir, lyginant gautus rezultatus su kitais baziniais šildymo būdais, apskaičiuotas kolektoriaus atsipirkimo laikotarpis. / Master thesis carried out an experimental study of unglazed transpired solar collector. During the experimental required measuring equipment was selected and installed. Performance of the collector was analyzed according to measured meteorological collector’s parameters data. Collector surface and supply air temperature, thermal efficiency and overall efficiency dependency on external factors was investigated. The study results are compared with constant or variable supply air flow rate and its impact on the operation of the collector. Collector operation impact to building’s external wall is investigated based on the principle of heat flow and using the selected measurement equipment. Study investigated possible heat inflow during the heating season and summer time, using collector as a shield against direct sunlight. Collector economical and energetic assessment was done using RETScreen software.

Magistro darbe analizuotos vakuuminių saulės kolektorių, skirtų vandeniui šildyti sistemos energetiniai parametrai, rodikliai ir konstrukcijos. Taip pat šiame darbe nagrinėjama vakuuminio saulės kolektoriaus energetinės charakteristikos. Darbą sudaro dvi dedamosios dalys: analitinė ir praktinė darbo dalys. Analitinėje dalyje apžvelgtos skirtingų tipų saulės kolektorių charakteristikos, saulės kolektorinių vandens šildymo sistemų veikimo principas ir panaudojimo galimybės. Trumpai apžvelgta perteklinės energijos panaudojimo galimybės ir saulės kolektorių sistemos projektavimo principas. Praktinėje darbo dalyje tirta saulės kolektorinė vandens šildymo sistema gamybinėmis sąlygomis. Atskleistas sistemos veikimo mechanizmas, ištirtas kolektorių našumas skirtingomis darbinėmis sąlygomis. Darbo pabaigoje suformuluotos atlikto tyrimo išvados. Pateiktos rekomendacijos tirtos saulės kolektorinės vandens šildymo sistemos administraciniam personalui. / Master's thesis analyses vacuum solar collectors for water heating system energy parameters, indicators and construction. Also vacuum solar collector system energy characteristics. The work consists of two component parts: the analytical and practical parts of the research. In the analytical part is an overview of the different types of solar collector performance, solar water heating systems operation and utilization. Short overview of surplus energy utilization possibilities and solar system design principle. In the practical part of the thesis is investigated solar collector water heating system under production conditions. Revealed mechanism of the system, investigated thermal performance under different operating conditions. In the end of research thesis conclusions are formulated. Recommendations were given for tested solar collector water heating system administrative personnel.

Absolicon Solar Collector AB in Härnösand, Sweden, develops concentrating solar collectors with a parabolic trough. In the solar collector trough, there is thermal loss due to convection. A convection suppressor was made and used as a method to reduce thermal loss due to convection in the trough. The objective of the project was to evaluate the convection suppressor for solar collectors with a parabolic trough and its impact on the performance (thermal loss characteristics) in two different orientations of the trough, horizontal and inclined. The performance of the solar collector was first measured without the convection suppressor; these results were compared to two previous quasi-dynamical tests of the solar collector performance made by two different institutes, Research Institute of Sweden and SPF Institut für Solartechnik (Switzerland). The comparison was made to validate the test results from the tests without the convection suppressor, which matched. Secondly, when the convection suppressor was made and tested in the two different orientations, the results of the performance with and without the convection suppressor was evaluated as well as the convection suppressor itself. The results showed a significant improvement of the solar collector performance in the aspect of reduced thermal loss when the convection suppressor was used, hence higher efficiency. / Absolicon Solar Collector AB I Härnösand, Sverige, utvecklar koncentrerande solfångare med ett paraboliskt tråg. I solfångarens tråg uppstår termiska förluster som en följd av konvektion. En konvektionsreducerare tillverkades och användes som metod för att minska de termiska förlusterna i tråget. Målet med projektet var att testa och utvärdera konvektionsreduceraren för koncentrerande solfångare med ett paraboliskt tråg samt dess inverkan på verkningsgraden i två olika positioner för tråget, horisontell och lutande. För att kunna mäta konvektionsreducerarens inverkan på solfångaren mättes först solfångarens prestanda utan konvektionsreduceraren i de två olika positionerna, detta resultat användes som referens efter validering. Valideringen gjordes genom att resultatet jämfördes sedan med två andra prestandamätningar (quasi-dynamical test) av solfångaren gjorda av två olika institut, Research Institute of Sweden och SPF Institut für Solartechnik (Schweiz). Därefter, när konvektionsreduceraren var tillverkat och testad i de olika positionerna på samma sätt som mätningarna utan konvektionsreducerare, jämfördes resultaten med och utan konvektionsreducerareet samt att en utvärdering gjordes av dess inverkan. Resultatet visade en signifikant förbättring av solfångarens prestanda i form av minskade termiska förluster när konvektionsreduceraren användes och därav ökad verkningsgrad.

In a country like Brazil, which has a high incidence of solar radiation, the use of solar energy is an alternative that has been researched and used with many advantages. This paper presents the design, construction and evaluation of the efficiency of a flat solar collector for pre-heating the air, executed with low cost materials, to be used in drying systems. The prototype of the solar collector with gravel bed was built to be made a survey of data from temperature and relative humidity, using a recording apparatus (data loggers), and carried out the calculations for determining the useful heat provided by the collector. Since in the state of Rio Grande do Sul there are approximately 85,560 farms growing tobacco, accounting to around 91,420 curing barns, for which the widest energy source is firewood, as a case study was proposed to use this solar collector to be used as a supplementary source of heat to the existing curing barns. A case study was conducted on the curing process, verifying the wood consumption needed for each phase of the process in order to determine its energy demands. It was observed that the application of a 3sqm surface collector represented a reduction of around 5.2% in firewood consumption, which demonstrated the economic viability of the system with a time of payback of 3.4 years. / Em um país como o Brasil, que possui alta incidência de radiação solar, o uso de energia solar é uma alternativa que vem sendo pesquisada e utilizada com muitas vantagens. O presente trabalho apresenta o projeto, a construção e a avaliação da eficiência de um coletor solar plano para pré-aquecimento do ar, executado com materiais de baixo custo, a ser utilizado em sistemas de secagem. O protótipo do coletor solar com leito de britas foi construido para que fossem feitos os levantamentos dos dados de temperatura e umidade relativa do ar, utilizando-se aparelhos registradores (data loggers), e efetuaram-se os cálculos para a determinação do calor útil fornecido pelo coletor. Sendo que no Rio Grande do Sul existem aproximadamente 85.560 propriedades produtoras de tabaco, que totalizam cerca de 91.420 estufas de cura, nas quais a fonte de energia mais utilizada é a lenha, como estudo de caso foi proposta a utilização deste coletor solar como sistema suplementar como aquecimento do ar no processo de cura do tabaco em estufas a lenha existentes. Um processo de cura foi acompanhado para verificação do consumo de lenha necessário para cada fase deste, para que fosse possível determinar a sua demanda energética. Observou-se que a utilização do coletor com 3m2 de área proporcionou a redução de 5,2% no consumo de lenha, o que demonstrou a viabilidade econômica da utilização do sistema com tempo de retorno do investimento de 3,4 anos.

Made available in DSpace on 2014-12-17T14:57:55Z (GMT). No. of bitstreams: 1 RivaldoFA.pdf: 1209805 bytes, checksum: 9afe6ff3479d3f42c70975fb75c6def0 (MD5) Previous issue date: 2009-10-01 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / It presents a solar collector to be used in a system for heating water for bathing, whose main characteristics are its low cost and easy manufacturing and assembly. The absorbing surface of the collector is formed by an aluminum plate with eight flaps where they lodge PVC pipes. The catchment area of solar radiation corresponds to 1.3 meters. The collector box was made of wood, is covered by transparent glass and thermal insulation of tire chips and expanded polystyrene (EPS). Absorber tubes were connected in parallel through the use of PVC fittings and fixed to the plate by the use of metal poles and rivets. The entire absorber received paint flat black for better absorption of sunlight. The system worked on a thermosiphon assembly and absorber of the collector has been tested in two configurations: with the tubes facing up, directly exposed to the impact of sunlight and facing down, exchanging heat with the plate by conduction. It was determined the most efficient configuration for the correct purpose. The solar collector was connected to a thermal reservoir, also alternative, low-cost forming the system of solar water heating. We evaluated thermal parameters that proved the viability of the heating system studied / Apresenta-se um coletor solar a ser utilizado em um sistema para aquecimento de ?gua destinada ao banho, cujas principais caracter?sticas s?o o baixo custo e f?ceis processos de fabrica??o e montagem. A superf?cie absorvedora do coletor e formada por uma chapa de alum?nio com oito aletas onde se alojam tubos de PVC. A ?rea de capta??o da radia??o solar global corresponde a 1,3 m2. A caixa do coletor foi confeccionada em madeira, tem cobertura de vidro plano transparente e isolamento t?rmico de raspas de pneu e poliestireno expandido (EPS). Os tubos absorvedores foram ligados em paralelo atrav?s do uso de conex?es de PVC e fixados a chapa pelo uso de perfis met?licos e arrebites. Todo o conjunto absorvedor recebeu pintura de preto fosca para uma melhor absor??o da radia??o solar incidente. O sistema absorvedor funcionou em regime de termo-sif?o e o conjunto absorvedor do coletor foi testado para duas configura??es: com os tubos voltados para cima, expostos diretamente a incid?ncia dos raios solares e voltados para baixo, trocando calor com a chapa por condu??o. Determinou-se a configura??o mais eficiente para o fim proposto. O coletor solar foi conectado a um reservat?rio t?rmico, de baixo custo formando o sistema de aquecimento solar de ?gua. Foram avaliados par?metros t?rmicos que comprovaram a viabilidade do sistema de aquecimento estudado

Made available in DSpace on 2014-12-17T14:57:58Z (GMT). No. of bitstreams: 1 AlexandreBL_DISSERT.pdf: 1416846 bytes, checksum: 84b2109ad5656c456f53841cfdcc3bc4 (MD5) Previous issue date: 2010-02-01 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / It presents a solar collector to be used in a system for heating water for bathing, whose main characteristics are low cost and easy manufacturing and assembly. The system operates under natural convection or thermosiphon. The absorbing surface of the collector is formed by twelve PVC pipes of 25 mm outside diameter connected in parallel via connections in T of the same material. The tubes were covered with absorbing fins made with recycled aluminum cans. We studied eight settings between absorber plate, thermal insulating EPS boards and thermal reservoirs 150 and 200 liters. It was determined the most efficient configuration for the correct purpose. We evaluated thermal parameters that proved the viability of the heating system studied / Apresenta-se um coletor solar a ser utilizado em um sistema para aquecimento de ?gua destinada ao banho, cujas principais caracter?sticas s?o o baixo custo e f?ceis processos de fabrica??o e montagem. O sistema funciona em regime de convec??o natural ou termosif?o. A superf?cie absorvedora do coletor ? formada por doze tubos de PVC de 25 mm de di?metro externo ligados em paralelo atrav?s de conex?es em T do mesmo material. Os tubos absorvedores foram recobertos por aletas confeccionadas com latas de alumino recicladas. Foram estudadas oito configura??es entre placa absorvedora, isolante t?rmico de placas de EPS e reservat?rios t?rmicos de 150 e 200 litros. Determinou-se a configura??o mais eficiente para o fim proposto. Foram avaliados par?metros t?rmicos que comprovaram a viabilidade do sistema de aquecimento estudado

A presente Dissertação é um estudo a respeito da problemática da utilização dos Sistemas de Aquecimento Solar Térmico para Aquecimento de Água com Coletores Planos em Circuito Direto, no crítico contexto da construção civil paulista para o ponto de vista da Arquitetura e do Urbanismo. Apesar do potencial solar do país e do padrão construtivo dos condomínios horizontais fechados da Região Metropolitana de São Paulo (RMSP), ainda não há regulamentação do uso do aquecimento solar térmico em alguns de seus municípios-sede. Atualmente tem havido a adesão espontânea ao sistema por parte de moradores das residências desses condomínios, decorrente da busca da redução dos gastos e da crescente conscientização ambiental e divulgação da tecnologia. Porém, ainda há necessidade de uma relação mais sistêmica dos coletores solares com a totalidade dos requisitos da edificação e do meio urbano, mesmo em se tratando da legislação específica. Buscando uma constribuição, aqui se propõe um modelo de estudo dos coletores baseado em escalas construtivas que, juntamente com a compreensão multidimensional do assunto, desafiam a atual dicotomia entre as ferramentas de qualidade e a sustentabilidade do ambiente construído. / The present work studies the problematic of using Solar Hot Water Systems by Direct Circuit, among the critics characteristics of civil construction in the State of São Paulo, Brazil. The point of view is of Architecture and Urban Planning. In spite of the high Brazilian levels of solar irradiation and the constructive pattern of horizontal closed condominiums of the metropolitan region of São Paulo (Brazil), which possess a large concentration of high incoming households, use of solar water heating is still not regulated in some of its comprising municipalities. Nowadays, the search for savings, diffusion of related technologies and raising environmental awareness have led to voluntary uptaking of such systems. Yet, regulation of solar collectors still lacks relating to certification of sustainable building practices, which does not relate to architectonic factors, in particular to main urbanistic features present in each given installation site. This work proposes an architectonic scale based model of studying it in order to pursuit the end of dichotomy between quality and sustainability.