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Vestlund, Johan. "Gas-filled, flat plate solar collectors." Doctoral thesis, Högskolan Dalarna, Energi och miljöteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:du-6182.
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This work treats the thermal and mechanical performances of gas-filled, flat plate solar collectors in order to achieve a better performance than that of air filled collectors. The gases examined are argon, krypton and xenon which all have lower thermal conductivity than air. The absorber is formed as a tray connected to the glass. The pressure of the gas inside is near to the ambient and since the gas volume will vary as the temperature changes, there are potential risks for fatigue in the material. One heat transfer model and one mechanical model were built. The mechanical model gave stresses and information on the movements. The factors of safety were calculated from the stresses, and the movements were used as input for the heat transfer model where the thermal performance was calculated. It is shown that gas-filled, flat plate solar collectors can be designed to achieve good thermal performance at a competitive cost. The best yield is achieved with a xenon gas filling together with a normal thick absorber, where normal thick means a 0.25 mm copper absorber. However, a great deal of energy is needed to produce the xenon gas, and if this aspect is taken into account, the krypton filling is better. Good thermal performance can also be achieved using less material; a collector with a 0.1 mm thick copper absorber and the third best gas, which is argon, still gives a better operating performance than a common, commercially produced, air filled collector with a 0.25 mm absorber. When manufacturing gas-filled flat plate solar collectors, one way of decreasing the total material costs significantly, is by changing absorber material from copper to aluminium. Best yield per monetary outlay is given by a thin (0.3 mm) alu-minium absorber with an argon filling. A high factor of safety is achieved with thin absorbers, large absorber areas, rectangular constructions with long tubes and short distances between glass and absorber. The latter will also give a thin layer of gas which gives good thermal performance. The only doubtii ful construction is an argon filled collector with a normal thick (> 0.50 mm) aluminium absorber. In general, an assessment of the stresses for the proposed construction together with appropriate tests are recommended before manufacturing, since it is hard to predict the factor of safety; if one part is reinforced, some other parts can experience more stress and the factor of safety actually drops.
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Reiter, Christoph Nikolaus. "Polymeric solar-thermal flat-plate collectors." Thesis, De Montfort University, 2014. http://hdl.handle.net/2086/10755.
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State-of-the-art solar-thermal flat-plate collectors suffer from a limited potential to decrease production costs for the necessary higher economic benefit of so-lar-thermal systems. Costly metallic materials and corresponding manufactur-ing processes prevent further cost reductions. For that issues, plastic materials can offer a promising approach. The main hurdle for the use of cost-effective plastics lies in the high thermal loads on the collector components — absorber and insulation — which were identified in a field-testing. The necessary overheating protection approaches to lower these thermal loads were investigated in a literature review. A large number of relevant concepts was evaluated related to achievable temperature reduction, influence on solar yield, additional costs and intrinsic safety. There-fore, a mathematical model was developed to determine the solar-thermal col-lector´s behaviour in a solar-thermal system for hot water and space heating. This way, the most promising overheating concepts were simulated and ana-lysed with regard to component temperatures and system performance. Omitting the selective absorber coating and reducing the backside insulation was found to be the most suitable solution for component materials with limited temperature resistance like polypropylene. In the second part of the research, collector design concepts were developed on the basis of the characteristics of plastic material processing. The identified unit costs showed savings of more than 50 % in comparison to stateof- the-art collectors. The analysis regarding temperature loads and annual solar yield by simulation proved the performance of the concepts. The collector costs and the simulation results were used to define the total costs of the solar-thermal sys-tems and to evaluate the economic benefits by means of the collector con-cepts. The benefits were similar to state-of-the-art set-ups. Thus, further adjustments at system level are necessary to lower the total costs. Therefore, the system set-up has to be harmonised with the collector requirements and investigated in detail.
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Sicner, Karen Maffitt. "A method for sizing flat plate solar collectors for space and hot water heating." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/21750.
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Ehrmann, Nicole [Verfasser]. "Development of selective coating systems for solar-thermal flat-plate collectors / Nicole Ehrmann." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2012. http://d-nb.info/1025758293/34.
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Nalis, Amrizal. "Quasi-Dynamic Characterization of Hybrid Photovoltaic/Thermal (PV/T) Flat-Plate Collectors." Doctoral thesis, Universitat de Lleida, 2012. http://hdl.handle.net/10803/84100.
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Un model híbrid transitòria fotovoltaic / tèrmic ha estat desenvolupat i validat experimentalment. La metodologia s'estén el model tèrmic quasi-dinàmica s'indica a la norma EN 12975 per involucrar el rendiment elèctric i estudiar el comportament dinàmic minimitzar les limitacions de l'hora de caracteritzar el col • lector. Una es mou cap enrere procediment mitjà de filtrat s'ha aplicat per millorar la resposta del model de condicions de treball variables. Quant a la part elèctrica, el model inclou les dependències tèrmiques i la radiació en les seves variables. Els resultats van revelar que els paràmetres característics inclosos en el model raonablement d'acord amb els valors experimentals obtinguts de la norma d'estat estacionari i els mesuraments de la corba característica IV. Després d'un procés de calibració del model proposat és una eina adequada per predir el comportament tèrmic i elèctric d'un col • lector solar híbrida, per un temps determinat conjunt de dades.A hybrid photovoltaic/thermal transient model has been developed and validated experimentally. The methodology extends the quasi-dynamic thermal model stated in the EN 12975 to involve the electrical performance and to consider the dynamic behaviour minimising constraints when characterising the collector. A backward moving average filtering procedure has been applied to improve the model response for variable working conditions. Concerning the electrical part, the model includes the thermal and radiation dependences in its variables. The results revealed that the characteristic parameters included in the model reasonably agree with the experimental values obtained from standard steady-state and IV characteristic curve measurements. After a calibration process the proposed model is a suitable tool to predict the thermal and electrical performance of a hybrid solar collector, for a specific weather data set
Se ha desarrollado un modelo dinámico para caracterizar colectores solares híbridos térmofotovoltaicos. La metodología extiende el modelo térmico estipulado en la norma EN 12975 involucrando la aportación eléctrica y estudiando el comportamiento dinámico para minimizar las restricciones a la hora de caracterizar el módulo. Se han implementado procedimientos de filtrado que mejoran la respuesta del modelo bajo condiciones variables. En cuanto a la parte eléctrica, el modelo incluye las dependencias térmicas y la radiación en sus variables. Los resultados obtenidos a partir de caracterización dinámica del colector híbrido PV/T revelaron que los parámetros característicos incluidos en el modelo concuerdan razonablemente bien con los valores experimentales obtenidos siguiendo el estándar de caracterización estacionaria, la capacidad calorífica efectiva y las mediciones de la curva característica IV. Después de un proceso de calibración, el modelo es una herramienta adecuada para predecir el comportamiento de un colector solar híbrido, para unas condiciones externas determinadas.
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Sumair, Faisal Ahmed. "Preparation and characterisation of eutectic nanofluids for heat transfer enhancement in flat plate solar collectors." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/48390/.
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Use of thermal energy storage (TES) materials in solar collectors is known to be the most effective way of storing thermal energy. The most conventional and traditional heat storage element is water. However, due to low thermal conductivity (TC) in vapor state its applications as a heat storage medium are limited. An alternative option is to utilize organic and inorganic TES materials as they both operate at low and medium temperature ranges. Organic TES materials such as paraffins are non-corrosive and possess high latent heat capacity. On the contrary, inorganic TES materials possess high density and appreciable specific heat capacity (SHC). Due to rapid progress and advancement in nanotechnology, varieties of nanomaterials were dispersed in various base fluid(s) to enhance thermo-physical properties. Here the current status and future development trends of TES materials has been presented. Furthermore, an extensive research on enhancement of TC and SHC of various TES material doped with nanomaterials has been discussed. Enhancement in heat capacity (HC) and thermal conductivity (TC) with dispersion of graphene (GE) nanoparticles in low temperature molten salt was investigated. Three different nanoparticle concentrations (0.01, 0.05 and 0.1 wt. %) were dispersed in molten salt composed of 5.76% NaNO3, 21.36% KNO3, 24.84% Ca(NO3)2, 41.08% CsNO3 and LiNO3 7.44% by weight. Doping of GE resulted in enhanced HC ranging from 5-13%, whereas, TC showed enhancement up to 2.44%, with respect to GE concentration. Various theoretical models were tested to predict TC and HC of GE doped molten salt. Maxwell and Hamilton-Crosser TC models show good agreement with experimental results with deviation of ±3% while Nan’s TC model over predicted TC value. Conventional HC equation fits well with the experimental data with deviation < 14%. Thus, the results obtained show the potential of GE doped molten salt as thermal energy storage (TES) medium in various heat transfer applications. This work also investigates the rheological and corrosion properties of graphene (GE) dispersed in eutectic salts. It was observed that doping of GE has significantly enhanced the viscosity of base salt. This enhancement in GE dispersed eutectic salt is mainly due to the presence of solid GE sheets and its coagulation in eutectic salts. Various concentrations of GE and temperature ranges were studied here. Eutectic salt dispersed GE behaved as non-Newtonian fluid at 70, 80 and 90 oC except at 200 oC, where it behaved as a Newtonian fluid. Viscosity of nanosuspension was predicted using Einstein’s equation. Furthermore, corrosion studies using ASTM D130 method were performed to analyse the effects of base fluid on copper and stainless steel (SS304) at elevated temperatures. Fourier transform infrared spectrometer (FTIR) result shows that the presence of all nitrate bonds in synthesized base salt and GE dispersed base salt. X-ray diffraction depicts that the doping of GE in eutectic salt does not alter the crystal structure of nitrate molecules. EDX results confirm that both Cu and SS304 material were corroded. SS304 exhibited constant corrosion with an increase in GE concentration dispersed in eutectic salt, whereas copper exhibited an increase in corrosion rate with an increase in GE concentration. Kinetic studies have been carried out for molten salt and GE dispersed molten salt. It was concluded that dispersion of GE has not altered decomposition rate of nitrate of ions. In application, we have fabricated and tested two types of solar collectors, i.e., solar thermal collector and photo-voltaic/thermal collector for TES material. Test was carried out to confirm the thermal performance of both solar collectors under water, base salt and GE dispersed base salt as TES. Results proved that in both types of solar collectors, all three concentrations of GE (0.01, 0.05 and 0.1 wt. %) dispersed base salt were having high thermal performance than water and base salt. Thus, it was concluded that GE dispersed molten salt can be successfully used as TES material in both solar collectors.
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Rodrigues, Felipe Pereira. "Manufacturing process and study of a selective surface for flat plate solar collectors by using granite residue." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12587.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorThe using of alternatives materials to replace selective surfaces is a natural trend, because it usually looks for improvements on efficiency of surfaces at the same time that it tries to reduce costs. Composites are already used on obtainment of some selective surfaces, however, if the possibility to use residue that would be discarded was associated to these characteristics, providing an added-value, it would brings some benefits like a possible reduction of manufacturing costs. Thus, this thesis proposes the obtainment and study of selective surfaces for flat plate solar collectors for low cost by using residue from granite industry. Three different surfaces was studied, two of them of obtained on the laboratory, one is granite powder made and the other is a surface composed by a mixture of granite powder and CRFO (Cr0,75Fe1,25O3); the third surface is a commercial one, known as TiNOX. To perform the tests of the surfaces it was built an experimental stand, it allows simulating a solar collector conditions. The tests was performed in a stagnation condition, in other words, there wasnât any water flow inside tubes. Through this experimental apparatus it was possible to test the three surfaces simultaneously. The field tests showed that the highest temperatures were reached by granite powder surface, which reached an average temperature of 119 ÂC, while the granite powder and CRFO mixture surface reached an average of 96 ÂC. The TiNOX achieve an average temperature of 101 ÂC. The three surfaces was compared each other through an equation that gives a global heat loss coefficient. The granite powder surface was the one which achieved the lowest global heat loss coefficient.
O uso de materiais alternativos com objetivo de substituir superfÃcies seletivas à uma tendÃncia natural, pois geralmente se busca melhorias na eficiÃncia das superfÃcies ao mesmo tempo em que se tenta diminuir os custos. SubstÃncias compÃsitas jà sÃo utilizadas na obtenÃÃo de algumas superfÃcies seletivas, no entanto, se for associado a estas caracterÃsticas a possibilidade de utilizar resÃduos que iriam ser descartados, conferindo aos mesmos um valor agregado, isso traria alguns benefÃcios, como uma possÃvel reduÃÃo de custos de fabricaÃÃo. Desta forma, o presente trabalho propÃe a obtenÃÃo e o estudo de superfÃcies seletivas para aplicaÃÃes em coletores solares de placa plana de baixo custo originÃrio do resÃduo da indÃstria de granito. Foram estudadas trÃs diferentes superfÃcies, duas delas foram obtidas no laboratÃrio, a superfÃcie a base de pà de granito e a superfÃcie composta pela mistura de pà de granito e CRFO (Cr0,75Fe1,25O3); e a terceira superfÃcie foi uma superfÃcie comercial, conhecida como TiNOX. Para a realizaÃÃo dos testes foi construÃda uma bancada experimental de madeira, de forma que fosse possÃvel simular as condiÃÃes de um coletor solar de placa plana. Os testes foram feitos em condiÃÃo de estagnaÃÃo, ou seja, nÃo havia fluxo de Ãgua atravÃs de tubos no coletor. AtravÃs desse aparato experimental foi possÃvel testar as trÃs superfÃcies seletivas simultaneamente. Os testes de campo mostraram que a superfÃcie composta por pà de granito foi a que atingiu as maiores temperaturas, com uma mÃdia de atà 119 ÂC, enquanto a superfÃcie obtida com uma mistura de pà de granito e CRFO chegou a temperatura mÃdia de 96 ÂC, jà a superfÃcie comercial atingiu uma mÃdia de 101 ÂC. As superfÃcies foram comparadas atravÃs de uma equaÃÃo que fornece o coeficiente global de perda de energia tÃrmica. Os menores coeficientes foram obtidos pela superfÃcie de pà de granito
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Linde, Daniel. "Evaluation of a Flat-Plate Photovoltaic Thermal (PVT) Collector prototype." Thesis, Högskolan Dalarna, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:du-24061.
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This Master thesis, in collaboration with Morgonsol Väst AB, was completed as a part of the Solar Energy engineering program at Dalarna University. It analyses the electrical and thermal performance of a prototype PVT collector developed by Morgonsol Väst AB. By following the standards EN 12975 and EN ISO 9806 as guides, the thermal tests of the collector were completed at the facility in Borlänge. The electrical performance of the PVT collector was evaluated by comparing it to a reference PV panel fitted next to it. The result from the tests shows an improved electrical performance of the PVT collector caused by the cooling and a thermal performance described by the linear efficiency curve ηth=0.53-21.6(Tm-Ta/G). The experimental work in this thesis is an initial study of the prototype PVT collector that will supply Morgonsol Väst with important data for future development and research of the product.
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Perumattil, Jose Rose Mary. "The analysis of flat plate solar collector with double-axis solar tracking." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-38932.
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Charlesworth, Peter S. "A full-scale and model study of convective heat transfer from roof mounted flat-plate solar collectors." Thesis, University of Sheffield, 1986. http://etheses.whiterose.ac.uk/5993/.
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This study is concerned with the convective heat transfer, due to the action of the wind, from the upper surface of roof mounted flat plate solar collectors. The ability to predict the quantity of heat transferred from a collector, in this manner, is necessary in order to facilitate the evaluation of the overall efficiency of a collector panel. Previous methods of determining this convection coefficient have generally relied upon extrapolations of small scale wind tunnel results to full-scale values. The validity of these methods is questionable, and it was found that there was a lack of full-scale data relating to the convection coefficient from the upper surface of a flat-plate collector. It was also found that no systematic attempt to relate model results to full scale values had been made. Full-scale experiments have been performed to evaluate the convective heat transfer coefficient, h, from the upper surface of a roof mounted flat plate. The convection coefficient was found to be dependent upon the wind speed as measured above the roof ridge line, V 6R, and to some extent upon the direction of the prevailing wind, G. Relationships between h and V 6R are presented, as are relationships between h and VH (the wind speed measured at the mid-panel height) and h and V 10 (the meteorological 10m wind speed). Small scale wind tunnel experiments were also performed. This was in order to assess the potential of using wind tunnel model results to predict accurately full-scale convective heat losses. These experiments showed some qualitative agreement with the full-scale tests. However, extrapolation of these model results to full-scale values rendered heat transfer coefficients in excess of those found in the full-scale work. Therefore the use of previously derived full-scale results from wind tunnel studies must be treated with caution. It is suggested that the full-scale results, presented here, represent a more satisfactory means of evaluating the convective heat transfer from the upper surface of roof mounted flat plate solar collectors.
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Munich, Chad Thomas. "Modeling of the Thermal Output of a Flat Plate Solar Collector." Thesis, The University of Arizona, 2013. http://hdl.handle.net/10150/293541.
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Traditionally, energy capture by non-concentrating solar collectors is calculated using the Hottel-Whillier Equation (HW): Q(u)=A(c)*F(r)*S-A(c)*F(r)*U(l)*(T(fi)-Tₐ), or its derivative: Q(u)=A(c)*F(r)*S-A(c)*F(r)*U(l)*((T(fi)-T(fo))/2-Tₐ). In these models, the rate of energy capture is based on the collector's aperture area (A(c)), collector heat removal factor (F(r)), absorbed solar radiation (S), collector overall heat loss coefficient (U(l)), inlet fluid temperature (T(fi)) and ambient air temperature (Tₐ). However real-world testing showed that these equations could potentially show significant errors during non-ideal solar and environmental conditions. It also predicts that when T(fi)-Tₐ equals zero, the energy lost convectively is zero. An improved model was tested: Q(u)=A(c)F(r)S-A(c)U(l)((T(fo)-T(fi))/(ln(T(fo)/T(fi)))-Tₐ) where T(fo) is the exit fluid temperature. Individual variables and coefficients were analyzed for all versions of the equation using linear analysis methods, statistical stepwise linear regression, F-Test, and Variance analysis, to determine their importance in the equation, as well as identify alternate methods of calculated collector coefficient modeling.
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Hobbi, Alireza. "Design of solar water heating systems for cold climate and study of heat transfer enhancement devices in flat-plate solar collectors." Thesis, Connect to online version, 2007. http://proquest.umi.com/pqdweb?did=1394676661&sid=2&Fmt=2&clientId=10306&RQT=309&VName=PQD.
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Johansson, Helena. "Nocturnal cooling : Study of heat transfer from a flat-plate solar collector." Thesis, Karlstad University, Faculty of Technology and Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1523.
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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.
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Hasan, Atiya. "Review of solar thermoelectric energy conversion and analysis of a two cover flat-plate solar collector." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40435.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007."February 2007."
Includes bibliographical references (p. 47-48).
The process of solar thermoelectric energy conversion was explored through a review of thermoelectric energy generation and solar collectors. Existing forms of flat plate collectors and solar concentrators were surveyed. A thermal analysis of a common two-cover flat plate solar collector was then performed. The model focused specifically on radiation absorption through the cover system and radiation and convection losses from the absorption plate to determine the parameters that most significantly affect the efficiency of the collector and the overall efficiency of the solar thermoelectric generator. In this case, collector efficiency was measured by the ratio of useable energy to incident solar energy. Overall generator efficiency was measured by power generated per unit area of the collector. It was found that of several parameters, the collector area had the most significant influence on collector efficiency. For the overall efficiency of the generator, the most significant parameter was the ratio of the collector area to the cross-sectional area of the thermoelectric elements (TE). The efficiency of the generator maximized at a ratio of 250:1, with a magnitude of 5.76 W/m2. The analysis exposes some weaknesses of the flat plate collector to show where future designs should focus for improvement.
by Atiya Hasan.
S.B.
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Iordanou, Grigorios. "Flat-plate solar collectors for water heating with improved heat transfer for application in climatic conditions of the Mediterranean Region." Thesis, Durham University, 2009. http://etheses.dur.ac.uk/174/.
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The aim of this research project is to improve the thermal performance of passive flat plate solar collectors using a novel cost effective enhanced heat transfer technique. The project work focuses on the process of energy conversion from the collector to the working fluid. This is accomplished by employing an aluminium grid placed in the channels of a collector to induce a gradient of heat capacitance. This novel technique is tested both theoretically by means of simplistic designs using Computational Fluid Dynamics (CFD) and experimentally using two unglazed collectors. One collector has the aluminium net inserted in its channels and it is tested against an identical conventional collector in order to have a direct comparison at the same time. The obtained CFD data and the experimental findings are coupled and show a good agreement. All the obtained results are validated with the literature. The results both theoretical and experimental demonstrate an enhancement in the heat transfer coefficient by 9 % resulting to an increase in the output temperature of the working fluid in the collector with the metallic insertion. Other parameters such as the Nusselt and Raleigh numbers supported these findings. Three novel expressions that correlate the Nusselt and the Rayleigh number, for different heat fluxes, were developed using data from CFD and experimental results. These correlations can be applied on any flat plate collector with an aluminium grid in its pipes, in order to predict its performance. Furthermore an existing lumped parameters model that predicts the output temperature of a collector was simplified and improved.
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Leitão, José Maurício de Moura. "Estudo de materiais poliméricos para a plicação em coletores solares planos." Universidade do Vale do Rio dos Sinos, 2018. http://www.repositorio.jesuita.org.br/handle/UNISINOS/7650.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Eficiência e economia na produção de energia são fatores-chave no desenvolvimento social e econômico de um país. A energia solar é uma fonte de energia limpa e renovável, utilizada em sua maior parte para o aquecimento de água por meio de coletores solares. Nos últimos 15 anos, os coletores solares planos vêm, devido ao apelo mundial para o uso de materiais mais facilmente recicláveis e ao baixo custo, utilizando cada vez mais materiais poliméricos, substituindo os convencionais. Para analisar quais materiais poliméricos podem ser usados em coletores solares planos, este trabalho realizou um teste de intemperismo acelerado nos materiais polissulfona (PSU), polietileno (PE) e policarbonato (PC). Destacam-se o PSU e o PE. O PSU tem o melhor resultado em relação ao nível de degradação, pois sua cadeia polimérica é composta por anéis aromáticos e fortes ligações de carbono, enxofre e oxigênio dentro da espinha dorsal do polímero. Adicionalmente, foram realizadas análises do infravermelho nos materiais envelhecidos na câmara de intemperismo acelerado pelo método ATR ou refletância total atenuada. Eles apresentaram, na cadeia molecular, pequenas mudanças nos espectros na região do infravermelho à medida que o tempo exposto na câmara de envelhecimento aumentava. Por fim, foi desenvolvida uma simulação numérica de um coletor solar plano na plataforma ESS (Engineering Equation Solver) em que foi simulado o efeito do número de tubos no absorvedor com diferentes materiais e foi simulada uma geometria de tubos de sessão quadrada no absorvedor. A simulação apresentou o melhor resultado com um absorvedor construído com 100 tubos de sessão quadrada de polissulfona, no qual a eficiência teoricamente pode chegar a 81,62%.
Efficiency and economy in energy production are key factors in the social and economic development of a country. Solar energy is a source of clean and renewable energy used for heating water through solar collectors. Over the past 15 years, due to the worldwide appeal for the use of more readily recyclable materials and their low cost, flat solar collectors have increasingly used polymeric materials to replace conventional ones. In order to assess which polymeric materials can be used in flat-plate solar collectors, an accelerated temperature test has been conducted on polysulfone (PSU), polyethylene (PE), and polycarbonate (PC). PSU and EP have stood out. PSU had the best result for degradation because its polymeric chain is composed of aromatic rings and strong bonds of carbon, sulfur and oxygen within the backbone of the polymer. Additionally, infrared analyses have been made of the materials aged in the accelerated temperature chamber according to the ATR method or attenuated total reflectance. They presented small molecular chain changes in the spectra in the infrared region as exposure time in the UV chamber increased. Finally, a numerical simulation of a flat solar collector was developed in the ESS (Engineering Equation Solver) platform in which the effect of the number of tubes in the absorber with different materials was simulated as well a geometry of square session tubes in the absorber. The simulation presented the best result with an absorber built with 100 polysulfone square session tubes, in which efficiency can theoretically reach 81.62%.
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Riess, Hermann. "Simulation, testing and design of a fully adhesive bonded flat plate solar collector for highly automated production." Thesis, De Montfort University, 2017. http://hdl.handle.net/2086/15041.
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This thesis presents simulation results and experimental data for a collector type with an all-round supported absorber and a fully adhesive edge bond that is produced on a highly automated production line. A literature review discussing measures to reduce the convective heat loss in flat plate collectors as well as on the status quo of the collector production was conducted. It was determined that an adaption of an existing automated production technique from the insulated glazing industry opens new paths towards a collector design allowing a mass production and an improved thermal collector efficiency. Within the thesis, the thermal and mechanical behaviour as well as the applied production method for this collector type are discussed. By implementing and validating a finite element model of the collector, the absorber deflection was analysed, different calculation approaches compared and conclusions drawn on the pressure change in the cavity of gas-filled collectors. Unlike stated in the literature, it was found that the thermal elongation of an all-round supported absorber has a considerable effect on the overall collector performance. Based on these conclusions, an optimised sheet-pipe absorber structure is introduced allowing a predictable absorber deflection and, thus, reduced chance of contact between absorber and glazing in collectors. The findings of the thermal simulation and, in particular, on the convective heat transfer confirmed the reliability of a recently extended convection calculation approach for solar collectors. Even though the gas-filled collector is capable of a superior thermal performance, simulation and testing results could not confirm the calculated efficiency increase given in recent literature. In comprehensive testing, the strengths and weaknesses of different batches of prototypes are discussed. Based on an economic analysis considering the collector production costs and the solar yield, the new approach was compared to a conventional solar collector.
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Deshpande, Dhananjay D. "Computer Modeling Of A Solar Thermal System For Space Heating." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1484142894264319.
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Zambolin, Enrico. "Theoretical and experimental study of solar thermal collector systems and components." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3422853.
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Flat-plate and evacuated tube collectors are the most widely used device to convert solar radiation into heat. In conventional applications they can provide energy for domestic hot water or space heating in combination with low water temperature systems.
Testing of thermal efficiency and optimisation of these solar thermal collectors are addressed and discussed in the present work.
A new set of experimental data has been used to evaluate the performance of flat-plate and evacuated collectors at various conditions. Efficiency is measured following the standard EN 12975: standard efficiency curves, input/output energy curves and daily efficiency curves have been obtained from tests.
This approach allows a more comprehensive comparison of the effective performance of the solar thermal collectors considered here.
A simulation tool of the flat-plate thermal collector is also proposed. The numerical model permits to obtain a “virtual collector” and provides information on the predicted performance without constructing prototypes. The three-dimensional steady-state model for flat-plate solar collector is validated comparing model predictions with experimental results obtained from experimental tests on two flat-plate collectors. Measures of the temperature profile in the copper sheet, in the glass cover and in the tubes, and an infrared analysis, are used to investigate the heat losses and optical characteristics.
The numerical model has been also used to analyse comparative effects of varying design choices, with regard to geometry and materials.
The evacuated tube collectors are in principle more expensive than flat-plate collectors and they are suitable for more higher temperature systems (space heating, absorption cooling machines..). Their geometry makes more difficult to fully characterize the collector performance. A new procedure to characterize these type of collectors has been developed and described in this thesis. Efficiency tests have been performed on a U-tube evacuated tubular collector, using a cylindrical absorber, both with and without external CPC (compound parabolic concentrator) reflectors.
Experimental results have been used to validate the new procedure and to provide information on the improvement of collectors’ performance obtained through the use of external CPC reflectors.I collettori solari termici maggiormente impiegati per convertire la radiazione solare in calore sono i collettori a tipologia piana e a tubi evacuati. Nelle applicazioni convenzionali essi vengono utilizzati per la produzione di acqua calda sanitaria o riscaldamento domestico in combinazione con sistemi a bassa temperatura. Prove d’efficienza termica ed ottimizzazione di questi dispositivi solari sono affrontati e discussi in questa tesi. Nuove prove sperimentali in varie condizioni sono state effettuate su collettori piani vetrati e a tubi evacuati per effettuare una nuova analisi comparativa. L’efficienza è stata misurata secondo le indicazioni della normativa europea EN 12975 ed inoltre si sono ricavate curve input-output e di efficienza media giornaliera. Questo approccio permette un confronto più ampio delle prestazioni effettive dei collettori solari considerati. Uno strumento di simulazione delle prestazioni dei collettori a geometria piana è anche proposto. Il modello numerico permette di ottenere un “collettore virtuale” e fornisce informazioni sulle prestazioni di un collettore senza costruirne un prototipo funzionale. Il modello tridimensionale stima le prestazioni di un collettore a geometria piana in condizioni stazionarie ed è stato validato confrontando le prestazioni stimate con i risultati sperimentali ottenuti su due collettori diversi. Misure di temperatura della piastra assorbente, della copertura vetrata, dei tubi dell’arpa ed analisi all’infrarosso sono stati utilizzati per investigare le dispersioni termiche e le caratteristiche ottiche della geometria considerata. Il modello è inoltre stato usato per analizzare gli effetti di alcune scelte progettuali riguardanti la geometria e i materiali dei componenti del collettore. I collettori solari a tubi evacuati sono in linea di principio più costosi dei collettori piani e sono idonei ad applicazioni a più alta temperatura (sistemi di riscaldamento, macchine ad assorbimento..). La loro geometria rende più difficile la caratterizzazione completa delle prestazioni del collettore. Una nuova procedura per caratterizzare questo tipo di collettori è stata sviluppata ed è qui descritta. Sono state eseguite prove sperimentali su un collettore a tubi evacuati, con tubi ad U, con assorbitore cilindrico, con e senza riflettori CPC (compound parabolic concentrator) esterni. I risultati sperimentali sono stati utilizzati per validare la nuova procedura e per fornire indicazioni sull’incremento dell’efficienza dovuto all’impiego dei riflettori CPC.
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Jesudhason, Maria Therasammal Terry Bruno. "Analysis of the Impact of Solar Thermal Water Heaters on the Electrical Distribution Load." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35302.
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In this research, the impact of solar thermal water heaters on the electric water heating load curve in a residential distribution circuit is analyzed with realistic hot water draw profiles. For this purpose, the electric and solar thermal water heater models are developed in MATLAB and validated with results from GridLAB-D and TRNSYS respectively. The solar thermal water heater model is developed for two types of collectors namely the flat plate and evacuated glass tube collector. Simulations are performed with the climate data from two cities - Madison, WI and Tampa, FL - which belong to two very different climate zones in the United States. Minute-by-minute electric energy consumptions in all three configurations of water heaters are modeled for a single water heater as well as a residential distribution circuit with 100 water heaters for daily as well as monthly time frames.The research findings include:
- The electric energy saving potential of a solar thermal water heater powered by auxiliary electric element is in the range of 40-80% as compared to an all-electric water heater depending on the site conditions such as ambient temperature, sunshine and wind speed. The simulation results indicate that the energy saving potential of a solar thermal water heater is in the range of 40-70% during winter and 60-80% during summer.
- Solar thermal water heaters aid in reducing the peak demand for electric water heating in a distribution feeder during sunshine hours when ambient temperatures are higher. The simulation results indicate that the peak reduction potential of solar thermal water heaters in a residential distribution feeder is in the range of 25-40% during winter and 40-60% during summer.
- The evacuated glass tube collectors save an additional 7-10% electric energy compared to the flat plate collectors with one glass pane during winter and around 10-15% during summer. The additional savings result from the capability of glass tube collectors to absorb ground reflected radiation and diffuse as well as direct beam radiation for a wider range of incidence angles. Also, the evacuated glass tube structure helps in reducing wind convective losses.
- From the simulations performed for Madison, WI and Tampa, FL, it is observed that Tampa, FL experiences more energy savings in winter than Madison, WI, while the energy savings are almost the same in summer. This is due to the fact that Tampa, FL has warmer winters with higher ambient temperatures and longer sunshine hours during the day compared to Madison, WI while the summer temperatures and sunshine hours are almost the same for the two cities.
- As expected, the simulation results prove the fact that lowering the hot water temperature set point will result in the reduction of electricity consumption. For a temperature reduction from 120 deg. F to 110 deg. F, electric water heaters save about 25-35% electric energy whereas solar thermal water heaters save about 30-40% auxiliary electric energy for the same temperature reduction.
- For the flat plate collectors, glass panes play an important role in auxiliary electric energy consumption. Flat plate collectors with two glass panes save about 10-15% auxiliary electric energy compared to those with no glass panes and about 3-5% energy saving compared to collectors with one glass pane. This is because there are reduced wind convective losses with glass panes. However, there are also transmittance losses from glass panes and there are upper limits on how many glass panes can be used.
Master of Science
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Sari, Ozgur Gokmen. "Exergy Analysis Of A Solar Assisted Absorption Heat Pump For Floor Heating System." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12604765/index.pdf.
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Solar assisted single-stage absorption heat pump (AHP) was used to supply energy to a floor-heating system by using the exergy methods. An existing duplex-house,in Ankara, with a heating load of 25.5 kW was analysed. Heating loads of the spaces in the building were calculated and a floor heating panel was modelled for each space leading to the capacity of the AHP before it was designed. Solar energy was delivered to the evaporator and high temperature heat input delivered to the genarator are met by auxiliary units operating with natural gas.The solar energy gained by flat-plate collectors was circulated through AHP.The anaysis performed according to the storage tank temperature reference value if the water temperature leaving the storage tank exceeds a predetermined value it is directly circulated through the floor heating system.
Exergue analysis were carried out with Mathcad program. Exergy analysis showed that irreversibility have an impact on absorption system performance.This study indicated which components in the system need to be improved thermally.A design procedure has been applied to a water-lithium-bromide absorption heat pump cycle and an optimisation procedure that consists of determinig the enthalpy, entropy ,exergy, temperature, mass flow rate in each component and coeficient of performance and exergetic coefficient of performance has been performed and tabulated.
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Schreiber, Rafael Gustavo. "Estampagem incremental e soldagem FSW para fabricação de coletor solar." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/183075.
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Este trabalho apresenta um modelo inovador de coletor solar plano, com placa absorvedora fabricada por Estampagem Incremental e Soldagem FSW (Friction Stir Welding). Esta placa absorvedora é constituída de duas chapas de alumínio AA1200-H14 com espessura de 1 mm, estampadas e soldadas em simetria, a fim de que na união das chapas sejam deixados canais para passagem de água. Neste estudo foi realizada a caracterização do material por Ensaio de Tração e Ensaio Nakajima. Para determinação dos parâmetros de Estampagem Incremental foram realizados 16 experimentos com ferramenta de diâmetro df = 9,5 mm, variando a rotação de N = 50 rpm a 800 rpm e o incremento vertical de Δz = 2 mm a 0,2 mm, mantendo o avanço em = 250 mm/min. E também foram realizados 3 experimentos com ferramenta df = 22 mm, variando o incremento vertical de Δz = 2 mm a 0,5 mm, mantendo a rotação em N = 50 rpm e o avanço em = 250 mm/min. Para determinação dos parâmetros de Soldagem FSW foram realizados 4 experimentos com ferramenta de ombro de diâmetro 8 mm e pino roscado M3x0,5, mantendo a rotação em N = 1500 rpm e variando o avanço entre = 100 mm/min a 400 mm/min. Em seguida foi fabricado um protótipo de placa absorvedora de coletor solar com área de 0,12 m². Nos experimentos realizados foi constatado que é possível obter maiores deformações na Estampagem Incremental do que na Estampagem Convencional e que as deformações são mais elevadas quando se utiliza menores diâmetros, maiores rotações e menores incrementos verticais da ferramenta. Na Soldagem FSW não foi constatada influência na qualidade do cordão de solda em relação à variação do avanço da ferramenta. Neste estudo também se verificou que é possível fabricar protótipos de placas absorvedoras de coletores solares pelos processos de Estampagem Incremental e Soldagem FSW. No entanto, para coletores em tamanho comercial, novos estudos são necessários para melhorar a forma de fixação das chapas durante a Soldagem FSW.This work presents an innovative model of flat plate solar collector, with absorber plate manufactured using Incremental Sheet Forming (ISF) and Friction Stir Welding (FSW). This absorber plate consists of two AA1200-H14 aluminum sheets with a thickness of 1 mm, stamped and welded in symmetry, in order to leave channels for the passage of water. In this study the characterization of the material by Nakajima Test and Traction Test was performed. In order to determine the parameters of ISF, 16 experiments were performed with a tool of diameter df = 9.5 mm, varying the rotation speed of N = 50 rpm at 800 rpm and the step down of Δz = 2 mm to 0.2 mm, maintaining the feed rate at = 250 mm/min. Also, 3 experiments with tool df = 22 mm were performed, varying the step down of Δz = 2 mm to 0.5 mm, maintaining the rotation speed at N = 50 rpm and the feed rate at = 250 mm/min. For determination of FSW parameters, 4 experiments with 8 mm diameter shoulder tool and M3x0.5 pin were performed, maintaining the rotation speed at N = 1500 rpm and varying the feed rate from = 100 mm/min to 400 mm/min. A prototype solar collector absorber plate with a 0.12 m² area was then manufactured. In the experiments carried out, it was found that it is possible to obtain greater deformations in the ISF than in the Conventional Stamping and that the deformations are higher when using smaller diameters, higher rotations and smaller step downs of the tool. In FSW, no influence was observed in the quality of the weld bead in relation to the variation of the tool feed rate. In this study it was also verified that it is possible to manufacture prototypes of solar collector absorber plates by the processes of ISF and FSW. However, for commercial size collectors, further studies are needed to improve the way the plates are fixed during FSW.
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Silva, Daniel dos Santos. "Desenvolvimento de uma ferramenta computacional para dimensionamento de coletores solares de placa plana." Universidade do Vale do Rio dos Sinos, 2012. http://www.repositorio.jesuita.org.br/handle/UNISINOS/4315.
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O uso da energia solar, como alternativa energética renovável, tem tomado um destaque fundamental no cenário mundial. Em especial, esse tipo de energia utilizado para aquecimento de água, tanto para uso doméstico como industrial representa um mercado mundial com crescimento em torno de 15% ao ano. No Brasil, esse crescimento deve-se, principalmente, aos programas habitacionais patrocinados pelo governo federal, além dos apelos cada vez mais fortes no sentido de buscar-se uma sustentabilidade energética e de economia através da diminuição do consumo de eletricidade e gás. Um sistema de aquecimento de água com energia solar é composto basicamente por coletor e reservatório térmico. Esses dois componentes representam quase a totalidade dos custos de instalação e isso ocorre principalmente em função dos materiais utilizados (cobre, alumínio e aço inoxidável) e dos processos de fabricação utilizados. Uma das formas para reduzir esses custos é a utilização de outros materiais mais baratos para a confecção de coletores e reservatórios e também de novos processos, mais ágeis e autômatos.Para contribuir com a solução desse problema, esse trabalho apresentará o desenvolvimento de uma ferramenta computacional que facilite a avaliação do rendimento térmico de diferentes composições de coletores solares de placa plana. Essa ferramenta foi desenvolvida sobre a plataforma EES (Engineering Equation Solver), pela sua facilidade de implementação, disponibilidade de funções de propriedades térmicas de fluidos, materiais e de escoamento. O programa segue um modelamento matemático baseado na teoria de Hottel-Bliss_Whillier e permite a entrada de dados relacionados aos parâmetros construtivos do coletor, como diâmetro dos tubos e espaçamento, espaçamento absorvedor-cobertura, material dos tubos, material da placa coletora e espessuras, material da cobertura e espessuras de isolamento, além de variáveis ambientais. Como dados de saída o programa fornece o desempenho térmico do coletor, calor útil, perdas térmicas, temperatura de estagnação, entre outros dados fundamentais de projeto. Os modelos matemáticos adotados na construção do programa foram validados através do confronto dos resultados calculados com dados obtidos experimentalmente em testes realizados pelo Test Center for Thermal Solar Systems do Fraunhofer Institut Solare Energie Systeme e pelo Institut für Thermodynamik und Wärmetechnik. Após a validação, a ferramenta é utilizada para avaliar o rendimento térmico de coletores com outros materiais construtivos, características óticas e termodinâmicas e também aspectos construtivos como a otimização do espaçamento de tubos, distanciamento entre cobertura e placa coletora, entre outros apresentados no capítulo quatro.
The use of solar energy as an alternative renewable energy, has taken a key highlight in the scene in different parts of the world. In particular, this type of energy used for heating water for domestic use becomes for a growing world market, mainly due to housing programs sponsored by the federal appeals beyond the increasingly strong in the sense of trying to achieve a sustainable energy and economy by reducing the consumption of electricity and gas. A system for heating water with solar energy is basically composed of collector and storage tank. These two components account for almost the entire cost of installation and this is mainly due to the materials (copper, aluminum and stainless steel) and the manufacturing processes used. One way to reduce these costs is the use of other cheaper materials for the manufacture of collectors. and reservoirs as well as new processes, more agile. To contribute to solving this problem, the present study the development of a software tool that facilitates the evaluation of the thermal efficiency of different compositions of flat plate solar collectors. This tool was developed on the platform EES (Engineering Equation Solver) for its ease of implementation, availability of functions of the thermal properties of fluids, materials and marketing.the program follows a mathematical model based on the theory of Hottel-Bliss_Whillier and allows entry of data related to the construction parameters of the collector, such as pipe diameter and spacing, spacing absorber-cover, the pipe material, the absorber material and thickness of material coverage and thickness of isolation and environmental variables. As output data the program provides the thermal performance of the collector, useful heat, thermal losses, stagnation temperature, and other fundamental data design.the mathematical models adopted in the construction of the program were validated by comparing the calculated results with data obtained experimentally by renowned research centers in Germany, as test center for thermal solar systems of Fraunhofer Institut Solare Systeme and Institut für Energie und Wärmetechnik Thermodynamik. After validation, the tool is used to evaluate the thermal performance of collectors with other building materials, optical characteristics and thermodynamic aspects of construction as well as the optimization of the spacing tubes, distance between absorber plate and cover, among others presented in chapter four.
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Filatov, Artem. "Concentrating Collector for Torsång District Heating System." Thesis, Högskolan Dalarna, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-28539.
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In this thesis report for Dalarna University in Borlange and Absolicon company the study of a possibility to add an array of concentrating solar collectors to a Torsång district heating system was done. The whole idea of this work was to make a simulation of this kind of system, trying to get 15-20% of solar fraction, and make an economical evaluation. At the same time, another goal was to make two comparisons: between concentrating and flat-plate collector in the same system, and between two tools for collector analysis – Polysun and Absolicon tool, based on TRNSYS, which was designed to estimate the output of the collector for a certain temperature, without any load. During the study, the analysis of the simulating tools was made and the combination of those two tools was used. Using long iteration cycles, involving changing the field layout, number of collectors and distance between collector rows in flat-plate collector case, both types of collectors were analyzed. The method of the analysis was to get an equal output of the field and see the differences, which appear while using different collector types.
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Farah, Hamad. "Hybrid solar system for heat and electric demands in a simple housing within Sweden and China." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40596.
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The access to ideal heating and power techniques has always been highly thought after.This is mainly due to the development in housing architecture and the cold nature of certain regions which has led to an increase in popularity of the heating market and modernised heating technologies. The current DH systems make use of CHP plants for thegeneration of power and electricity. These CHP plants for the most part, are powered through biomass and during winter periods the demand for heating is highly increased.The biggest issue with relying on biomass solely is the constant need to burn wasteproducts which not only results in increasing the demand for consuming in more waste,but also results in producing remains (by-products) that cannot be broken down further and hence might require the utilization of land-space (landfills) for their disposal. Solar modules on the other hand, have gained increased popularity in the recent age. This is mainly due their extremely high flexible ability in converting solar irradiance intoelectrical and thermal energies. This study will try to provide a comprehensive study intothe utilization of a hybrid solar system that combines a standard PV module with a flat-plate collector through estimating the energy demands for a simple housing within Sweden and China. This will be the main aim of the study, however the possibilities of integrating this hybrid solar system alongside current DH systems will mostly be discussed in the first sections to proof the possibility of executing such a system. The theoretical work carried out will only include simulations of having just separate,standalone PV and flat-plate collector modules. However, designing a hybrid solar and DH system will not be the major focus of this study. The results at the end of the report,concluded that the electrical production for the Swedish case were noticeably higher thanthat of the Chinese case in spite of maintaining the same load values through both cases and higher solar irradiation for the Chinese case. Due to PVsyst simulation constraints,the results show that the investment cost of the Swedish PV (electrical component) module was about 3.6 times greater than that of the Chinese which could possibly mean that the Swedish case has a bigger PV module area than the Chinese case in order to meetel ectricity demand monthly. However, when it came to the thermal energy production, it was possible to assume different collectors cases and hence an area of 7m2 was chosen for the Swedish perspective while an area of 4m2 has been considered for the Chinese case. The thermal useful energy values where then compared with heating demands for both of the cases. Finally, the thesis concluded that there was no requirement for having an integrated DH network within the standalone houses, having small electricity and heat demand and hence, it might be more beneficial to have an integrated DH and solar system within more densely populated housing areas.Efterfrågan på tillgången till idealisk uppvärmning och effektiva tekniker har alltid varithög. Detta beror främst på utvecklingen inom arkitektur och den kalla naturen i vissaregioner som har lett till en ökad popularitet av värmemarknaden och moderniseradevärmeteknologiert. De nuvarande fjärrvärme-systemen använder kraftvärmeverk förproduktion av kraft och elektricitet. Dessa kraftvärmeanläggningar drivs till stor delgenom biomassa och under vinterperioderna ökar efterfrågan på uppvärmning mycket.Det största problemet med att förlita sig på biomassa enbart är det ständiga behovet avatt bränna avfallsprodukter som inte bara resulterar i att öka efterfrågan på konsumtionav fler avfallsprodukter utan också resulterar i att producera rester (biprodukter) sominte kan brytas ned ytterligare och därmed kan kräva användning av markutrymme fördeponering. solar-moduler å andra sidan har ökat popularitet under de senaste åren.Detta beror främst på deras extremt höga flexibla förmåga att konvertera solbestrålningtill elektrisk och termisk energi. Denna studie kommer att försöka tillhandahålla enomfattande studie av användningen av ett hybridsolsystem som kombinerar en standardPV-modul med en flatplate collector för att simulera en solar-modul samt caselera enfristående version genom att uppskatta energikraven för en enkel bostad i Sverige ochKina. Detta kommer att vara huvudmålet med studien, men möjligheterna att integreradetta hybrida solsystem tillsammans med nuvarande DH-system kommer mestadels attdiskuteras i de första avsnitten för att bevisa möjligheten att utföra ett sådant system. Detteoretiska arbetet som utförs kommer endast att innehålla simuleringar av att bara ha enfristående PV- och flatplate collector module, men att utforma ett hybrid sol- och DHsystemkommer inte att vara huvudfokus för denna studie. Resultaten i slutet avrapporten drog överraskande slutsatsen att den elektriska produktionen för den svenskacaselen var märkbart högre än den för den kinesiska caselen trots att de båda caselernabibehöll samma belastningsvärden och högre solbestrålning för den kinesiska caselen.Detta kan förklaras av skillnaden i modulpriser vid simulering genom PVsyst därinvesteringskostnaden för den svenska PV-modulen (elektrisk komponent) var ungefär3,6 gånger större än den för kinesiska, vilket innebär att PVsyst antar ett störremodulområde för svensk modul och därmed mer energiproduktion. Men när det kom tillvärmeenergiproduktionen, var det möjligt att anta olika samlarfall och följaktligen valdesett område på 7m2 för det svenska perspektivet medan ett område på 4m2 har beaktatsför den kinesiska och värmevärden för användbar energi där jämfördes sedan med dekrav som krävs för uppvärmning i båda fallen. Slutligen drog avhandlingen slutsatsen attdet inte fanns något krav på att ha ett integrerat DH-nätverk i de fristående husen ochdärför kan det vara mer fördelaktigt att ha ett integrerat DH och solsystem i tätarebebyggda bostadsområden.
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Vieira, Samuel Guerra. "ObtenÃÃo, caracterizaÃÃo e aplicaÃÃo de uma nova superfÃcie Seletiva para coletores solares tÃrmicos." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=6923.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoO estudo de superfÃcies seletivas para coletores solares tÃrmicos, hà alguns anos, enfoca o uso de pastas e tintas para recobrir chapas de cobre ou alumÃnio, formando a placa absorvedora do coletor. Essas tintas ou pastas sÃo eletrodepositadas em placas metÃlicas, sendo este processo muitas vezes responsÃvel pelo levado custo de superfÃcies seletivas. O uso de compÃsitos obtidos a partir do Ãxido de cromo, Ãxido de ferro e Ãxido de titÃnio em um processo cerÃmico, utilizando a tÃcnica de deposiÃÃo por screen-printing pode ser uma alternativa para a obtenÃÃo de novas superfÃcies seletivas que tenham eficiÃncia prÃxima Ãs tintas e pastas jà comercializadas e com baixo custo de fabricaÃÃo. O objetivo deste trabalho à obter e caracterizar superfÃcies seletivas à base de cromo, ferro e titÃnio e comparÃ-las com outras superfÃcies jà comercializadas (Ãxidos metÃlicos), encontrar os valores da absortividade e caracterizar as mesmas por espectroscopÃa raman e infavermelho.
The study of selective coating for thermal solar collectors has been carried out with focus on the use of selective paints and coatings for copper and aluminum plates, which are used to manufacture the absorber plate. The processes, such as electrodeposition, used in these paints and coatings are expensive and they increasing the price of the final product. The use of composite obtained from chromium oxide, iron oxide, and titanium oxide in a ceramic process using the screen-printing deposition technique is an alternative to develop new selective coating with approximately the same thermal efficiency, but at a lower cost than the commercial ones. The results show that the absorptivity values measured with the new coatings are close to those presented by the manufacturers in the commercial sufaces. The objective is to obtain and characterize selective surfaces based on chromium, iron and titanium and compares them to other areas already marketed (metal oxides), find the values of absorptivity and characterize them by raman and infrared spectroscopy.
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Pech, Ondřej. "Energetická simulace provozu solárních kolektorů v nízkoenergetickém rodinném domě s teplovzdušným vytápěním." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-228992.
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The thesis deals with energy simulation of a solar energy system in a low-energy family house with warm-air heating. The simulations performed resulted in the assessment of the energy contribution of four solar systems with different types of collectors. The profitability and return of investment for the particular system have been evaluated based on investment costs and the savings gained. The theoretical part includes an introduction to the solar energy field, solar panel systems and the passive house concept. The practical part is devoted to description of the simulated object models as used in the TRNSYS environment, the simulation results evaluation along with the assessment of the economic return on investment. The conclusion recommendations regarding a suitable type and size of the solar panel with respect to the economic criteria chosen are given.
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Elhabishi, Ali Mohamed. "Optimising collector plate geometry for a specific solar syphon system design." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2385.
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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016.Solar energy is still not being used effectively in countries in the developing world, though it's a partial solution to the problem of shortage and expensive energy. Normally harvested through flat plate collectors, converting solar radiation into heat is the most direct application that can be effected in water heating systems. Many researchers have attempted to develop means of improving the efficiency of the flat plate solar energy collector; however there appears to be no evidence of any work regarding the effect of geometric configuration on the performance of flat plate solar collector. This study presents results obtained when comparing the performance of a solar water heating system equipped with three manufactured flat plate solar collector panels of numerically identical surface area but of different geometric configuration as they were individually attached to a typical geyser. Data was obtained inside a laboratory. The amount of heat acquired from flat plate collectors of solar energy depends primarily on their surface area that is exposed to the solar irradiance, however, the geometry of the collectors was thought that it might affect to some extent the amount of heat harvested. The circulation of the water from the panel to the geyser was due to the self-induced thermo-syphon effect. The results obtained during the test period (7 hours per day for two consecutive days) indicated that the system’s thermal efficiency was best when the square geometrical configuration collector was used. A dimensional analysis using the Π Buckingham method that was performed on the parameters affecting a flat plate solar collector yielded three dimensionless numbers that lead to a power law relationship which might be useful in enhancing solar water heating systems’ design.
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Grassie, Tom. "Optimisation of fluid-flow in a flat plate solar water heater." Thesis, Edinburgh Napier University, 2001. http://researchrepository.napier.ac.uk/Output/3862.
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Lämmle, Manuel [Verfasser], and Hans-Martin [Akademischer Betreuer] Henning. "Thermal management of PVT collectors : : development and modelling of highly efficient glazed, flat plate PVT collectors with low emissivity coatings and overheating protection." Freiburg : Universität, 2018. http://d-nb.info/1168145651/34.
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Khan, Zakir. "Energy recovery at thermodynamic expansion and thermal boosting through convection in flat plate solar thermal systems." Thesis, Bournemouth University, 2018. http://eprints.bournemouth.ac.uk/31116/.
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Fossil fuels have served mankind to meet energy needs in both domestic and commercial applications for a considerable length of time. However, fossil fuels have environmental implications such as emission of harmful gases, depletion of ozone layer and climate change. Moreover, the ever rising prices and limited resources of fossil fuels have obstructed the uninterrupted supply of energy. Therefore, there is a dire need to develop renewable energy technologies that can sustain energy supply with increasing demands. Due to inexhaustible amount of clean solar energy, engineers and researchers are engaged in developing technologies to minimise dependency on fossil fuels. Solar collectors are utilised to use solar heat to increase the heat energy of thermo-fluids or heat transfer fluid (HTF), which can operate Organic Rankine Cycle (ORC) to generate electricity. However, the extensive gain from solar energy is restricted due to unreliability of solar energy during changing weathers and lack of availability at nights. Therefore, thermal energy storage (TES) system can provide a viable solution to respond to varying levels of solar energy. Literature review indicated that phase change materials (PCM) based latent heat storage (LHS) systems are promising TES technique due to their high thermal storage density, operation at isothermal conditions and wide range availability of PCMs. However, large-scale practical utilisations of LHS systems are limited due to restrained charging and discharging rates caused by low thermal conductivity of PCM. Hence, this research is focused on numerical and experimental analyses conducted in developing an efficient and effective TES technology with novel heat transfer mechanism and novel thermal storage materials to sustain continuous generation of heat and power for low temperature practical applications. In this research, numerical investigations were conducted to propose an optimum and novel design solution for shell and tube heat exchanger with multiple tube passes and longitudinal fins for improved thermal performance. Parametric investigations were conducted to examine the influence of number and orientations of tube passes in the shell container, geometrical dimensions of longitudinal fins, construction material for shell, tube passes and longitudinal fins, and operating temperature of HTF on phase transition rate and overall enthalpy of LHS system. Further, the proposed design was developed and commissioned with a connection to flat plate solar collector to examine thermal performance at varied operating conditions. Paraffin (RT44HC) was employed as PCM in shell container and water was utilised to circulate in tube passes to transfer thermal energy gained at solar collector to paraffin in shell container. Thermal performance was evaluated by conducting series of charging and discharging cycles at varied operating conditions to examine the charging/discharging rate, accumulative thermal energy gain/release and mean charging/discharging power. Furthermore, numerical and experimental analyses were conducted to evaluate nano-additives enhanced paraffin samples, which were developed by incorporating aluminium oxides (Al2O3), aluminium nitride (AlN) and graphene nano-platelets (GNP) nano-additives in base paraffin. Based on numerical and experimental results and recommendations, numerical simulations were conducted on coupled thermal performance enhancement techniques with longitudinal fins and graphene nano-additives enhanced paraffin samples. It was noticed that phase transition rate for coupled thermal performance enhancement techniques was significantly enhanced by 75.46% as compared to no longitudinal fins orientation with pure paraffin. Likewise, the proposed LHS system can efficiently charge and discharge 14.36 MJ and 12 MJ of thermal energy in as less as 3 h and 1.5 h, which ensures the large-scale practical utilisation in both domestic and commercial applications.
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Solmus, Ismail. "Theoretical And Experimental Investigation Of A Humidification-dehumidification Desalination System Using Solar Energy." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607622/index.pdf.
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In this thesis, experimental and numerical studies have been carried out to investigate the performance of a solar desalination system working on humidification-dehumidification principle under the climatological conditions of Ankara, Turkey. The desalination unit was configured mainly by a double-pass flat plate solar air heater with two glass covers, pad humidifier, storage tank and dehumidifying exchanger. The system used in this work is based on the idea of closed water and open air cycles. A computer simulation program based on the mathematical model was developed by means of MATLAB software to study the effect of different environmental, design, and operational parameters on the desalination system productivity. In this simulation program, the fourth order Runge-Kutta method was used to solve the energy balance equations simultaneously and numerically. In order to compare the obtained theoretical results with experimental ones and validate of the developed mathematical model of the system, an experimental study has been carried out. For that, an experimental set-up was designed, constructed and tested at the solar house of the Mechanical Engineering Department of METU. In addition, the existing solar desalination system was integrated with an evacuated tubular solar water heater unit (closed water circulation) and performance of the system has been studied experimentally.
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Egerle, Dušan. "Kotelny na biomasu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226022.
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The aim of this project is heating and warm water preparation for apartment block in Choceň (Pardubice region). Apartment block has three aboveground heated floors and one underground unheated floor. The heat source is gasifying firewood boiler or pellet boiler which is at the same time used for water heating but only in the winter time. The other parts of the year the solar collectors are installed and used for water heating. The heat source is located in detached room with its own access, in boiler room.
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Shyam. "Performance analysis of photovoltaic thermal flat plate collectors and direct absorber solar collectors." Thesis, 2017. http://localhost:8080/xmlui/handle/12345678/7311.
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MISHRA, RAJAT KUMAR. "THERMAL PERFORMANCE ANALYSIS OF VARIOUS GAS FILLED SOLAR FLAT PLATE COLLECTORS." Thesis, 2019. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16690.
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The fossil fuels are depleting day by day and energy demand is rising at a high rate. The gap between this depletion and demand can be narrowed by the use of solar energy. The most direct application of solar energy is the conversion of solar radiation into thermal energy like in water heating system which is generally done using flat plate solar collectors. This research focuses on the media between the absorber plate and the glass cover. This study presents the performance evaluation of different gas filled solar flat plate collectors filled with gases like carbon dioxide, methane, nitrous oxide, R410a, sulphur hexafluoride, R22 and R134a to make greenhouse environment inside collector Their performances have been compared with the air filled solar flat plate collector. The complete analysis has been done for four different months (January, June, August, and October) under composite climatic condition of Delhi using MATLAB. The performance characteristic curves and equations for all gas filled collectors have been developed under clear sky condition.
The results show that there is 5.6, 2.8 and 2.3% decrease in average overall heat loss coefficient for carbon dioxide, nitrous oxide and R22 filled solar flat plate collector respectively as compared to air filled solar flat plate collector under clear sky condition. The average instantaneous efficiency has increased about 0.9% for carbon dioxide filled solar flat collector and 0.41% for both nitrous oxide and R22 filled solar flat plate collectors. Other filled gas solar flat plate collectors have lower performance than air filled solar flat plate collector. The average convective heat transfer coefficient between the absorber plate and glass cover decreases about 10.43% for carbon dioxide filled solar flat plate collector, 5.05% for nitrous oxide filled solar flat plate collector and 4.71% for R22 filled solar flat plate collector as compared to air filled solar flat plate collector.
The characteristic curve shows that the performance of carbon dioxide filled solar flat plate collector become better and better at higher water inlet temperature.
Thus, the carbon dioxide filled solar flat plate collector can be marked as the best among all these solar flat plate collectors. The MATLAB code that has been developed in this research can be used to analyze any gas filled solar flat plate collector.
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Huang, Chih-Chien, and 黃之健. "A Study on Flat Plate Evacuated Solar Collector." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/72421370390178170722.
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碩士大葉大學
機械與自動化工程學系
97
When the storage of fossil fuels become less and less, the application of solar energy gets more and more important. However, the solar thermal heating systems on the market are currently costly, heavy, and bulky. This thesis introduces the design of a novel solar collector, which unites the advantages of a flat plate collector and an evacuated tube collector to form a “flat plate evacuated solar collector”. The research studies the feasibility of this kind of solar collector; the study methods include the numerical simulations of fluid flow associated with heat transfers and the experiments on a real flat plate evacuated solar collector. The results show that the efficiency of the flat plate evacuated solar collector lies between the evacuated tube collector and flat plate collector and this novel solar collector is worth further study.
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Koo, Jae-Mo. "Development of a flat-plate solar collector design program." 1999. http://catalog.hathitrust.org/api/volumes/oclc/44706438.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1999.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 138-139).
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Samdarshi, Sanjoy Kumar. "Study of top heat loss factor of flat plate solar collector." Thesis, 1992. http://localhost:8080/xmlui/handle/12345678/6387.
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Sookdeo, Steven. "Experimental investigation of the thermofluid behaviour within a flat-plate solar collector." Thesis, 2008. http://spectrum.library.concordia.ca/976248/1/MR45476.pdf.
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Flat-plate solar collectors are used in solar water heating systems to transfer solar energy to water in the form of heat. The research on solar water heating systems is mainly focused on the design and optimization of the overall system with little attention given to study the thermofluid behaviour inside the collector. The collector is a very crucial part of the system as it is where the actual energy conversion talks place. In the present research, the thermofluid behaviour within the tube of a flat-plate solar collector for a forced circulation solar water heating system is experimentally investigated. Particle Image Velocimetry (PIV) was used to measure the velocity field within the collector tube, while thermocouples were used for temperature measurements. The experiments were performed for six flow rates under one unheated and two heated conditions. The mean velocity profiles for heated and unheated conditions show that the flow behaviour within the collector tube is significantly modified by the heating. With the heat addition, the location of the maximum velocity is in the lower half of the tube, and the magnitudes of mean and turbulent velocities increased with the heat flux. The temperature data indicated the formation of stably stratified layer of water in the upper region of the tube, which reduces the heat transfer rate. The heat transfer analysis showed that free convection is the dominant mode of heat transfer within the flat-plate solar collector.
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(5931191), Manikanta Kurri. "TRANSIENT OPERATION AND SIMULATION OF A FLAT PLATE SOLAR COLLECTOR WITH TANK AND THERMAL STORAGE." Thesis, 2019.
Find full textAbstract:
Global warming due to over usage of fossil fuels is leading to different kinds of
pollutions. Global warming can be controlled by switching non-renewable fossil fuels
with renewable alternative power sources like wind, solar, geothermal, biomass, and
ocean. Solar power is the most prominent alternative source around the world. Solar
power is being used as alternative power source in almost all countries around the
globe. Solar power uses radiation from sun to produce heat and the heat used for
different heating and cooling applications whereas electricity being one of them. Solar
power is being used in domestic applications as water heaters.
A solar collector is used to transfer energy from sun to heat water. A flat plate
solar collector is commonly used for water heating systems. Solar radiation is not
available entire day as other alternative energy sources so there may be a need to
store the collected radiation using a thermal storage system. This study considers a
solar collector system with a storage tank and phase change material (PCM). The
simulation of a transient process using one-dimensional mathematical model for the
collector and storage system with phase change materials (PCMs) is presented. The
collector used in this study is a flat plate model and paraffin wax encapsulated in
aluminum cylinders as phase change material (PCM). The thermal energy gained by
solar radiation can be stored for longer period in a system which has phase change
materials (PCMs) due to latent heat storage or enthalpy of fusion.
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Parida, Anshuman. "Fabrication and Experimental Studies of a Hybrid Flat Plate Solar Collector for Heating Pool Water." Thesis, 2011. http://ethesis.nitrkl.ac.in/2533/2/Final_Report__Anshuman.pdf.
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Warm water in swimming pool is more of a necessity than comfort in places where temperature drops down below 25°C during winter. So pool water heaters are used extensively at places like Hotels, Hospitals, and Clubs etc. to bring the water temperature to a comfort level. But conventional pool water heaters require a lot of energy (electrical/fossil fuel energy) to run. Laws have been enforced in many countries which restrict the use of direct electricity to heat pool water.
This project report gives a detailed outline of the fabrication procedure of a flat plate solar thermal collector, built out of locally available materials. The report also contains the experimentation work carried out with the Collector model to determine its efficiency and optimum parameters. A brief solar surveying work was carried out during the project which has been explained. Finally, a feasible and economic heating system design is proposed which takes into account the temperature data of the water and air collected from NIT Rourkela swimming pool and the qualitative aspects of the fabricated flat plate solar collector.
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Tsai, Cheng-Jung, and 蔡政融. "The Recycle Effect on Collector Efficiency of Flat-Plate Solar Water Heaters with Rectangular Flow Ducts." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/30446507747733960223.
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碩士淡江大學
化學工程與材料工程學系碩士班
95
The study presents theoretical and experimental results of the device performance on flat-plate solar water heaters with rectangular flow ducts under recycle operation. Comparisons of the collector efficiency were made between the present device and the conventional type collector. The theoretical and experimental results show that the collector efficiencies can be effectively enhanced by using recycle operation. The theoretical and experimental results of flat-plate solar water heaters with rectangular flow ducts have been carried out with as the recycle ratio, number of pair ducts, number of fins attached, aspect ratio of flow ducts, mass flow rate, inlet fluid temperature and incident solar radiation as the operating and design parameters. The collector efficiencies for flat-plate solar water heaters with external recycle increase with increasing recycle ratio, mass flow rate and incident solar, but decrease with increasing inlet water temperature and number of pair ducts. The effects of the recycle ratio and number of fins attached on the collector efficiency enhancement are represented graphically, where the power consumption increment under such recycle operations has also delineated.
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Chen, Chih-Cheng, and 陳志誠. "Thermal Performance Investigation of a Novel Flat-plate Solar Thermal Collector Using Metal-foam Blocks under Forced Pulsating Flow." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/978yjk.
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博士國立臺北科技大學
機電科技研究所
100
The solar energy, which is one of alternative renewable energy, becomes more important recently due to the gradual scarcity and derivative environment problems of traditional fossil fuels. The major component of any solar thermal system is the solar thermal collector for thermal energy convert. The efficiency improvement for flat-plate solar collector can reduce its size and obtain higher temperature fluid for wider application. A numerical simulation was carried out to investigate the characteristics of heat transfer enhancement for a novel flat-plate solar thermal collector using metal-foam porous blocks as heat sinks under forced pulsating flow. The analysis is based on the use of unsteady Navier-Stokes equation in the fluid region, the transient Darcy-Brinkman-Forchheimer flow model in the porous region, and the two-phase energy models employing local thermal non-equilibrium (LTNE) assumption on the thermal field. The above governing equations are incorporated with empirical equations of metal-foam. A finite-volume integration method is employed to solve the dimensionless coupled governing equations for this porous/fluid composite system through the use of a stream function-vorticity transformation. This study details the effects of variations in the major control parameters to illustrate important fundamental and practical results. The results show that the periodic alteration in the structure of recirculation flows, caused by metal-foam blocks and flow pulsating, has a direct impact on the flow and thermal characteristics. The synthetic method indeed can be considered as an effective method to augment heat transfer and improve the efficiency of solar thermal collector. Besides, the Darcy number is the most influential parameter in determining the validity of local thermal equilibrium (LTE). In general, when solid conduction is the dominant heat transfer mode, the more efficient the interfacial heat transfer between solid and fluid phases is, the more obvious the local thermal equilibrium becomes. Further, the useful correlated equations to predict Num are proposed by regression analysis here for the application of realistic engineering design.
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Parente, Joana Raquel Mendes Cação. "Estudo da interação térmica e dinãmica entre um escoamento gasoso e uma matriz porosa metálica." Master's thesis, 2014. http://hdl.handle.net/10316/38777.
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Dissertação de Mestrado Integrado em Engenharia do Ambiente apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A energia solar apresenta como fonte o Sol, origem de praticamente toda a energia que sustenta a vida e enorme potencial energético ainda com muito por explorar, principalmente em Portugal. Porém, este tipo de energia apresenta como desvantagens o facto de ser intermitente e apresentar grandes variações regionais. Como tal, torna-se necessário a melhoria dos sistemas tecnológicos principalmente no que diz respeito à eficiência dos mesmos. A presente dissertação apresenta como principal objetivo a caracterização duma matriz porosa metálica, de seu nome palha-de-aço, com o intuito de a utilizar como elemento absorvedor num coletor de placa plana. Para tal, estudou-se a interação térmica e dinâmica entre a referida matriz e um escoamento de ar, variando o caudal deste e o grau de porosidade e a orientação espacial da matriz. Para a obtenção dos valores referidos foi utilizada uma instalação experimental e um modelo teórico matemático. Obtidos os valores experimentais e os dados fornecidos pelo modelo teórico, obtiveram-se valores de coeficiente de transferência de calor entre 10 e 70 W.m-2.˚C-1, para orientação radial da matriz, e de 10 a 90 W.m-2.˚C-1, para a orientação longitudinal. Ainda na mesma instalação experimental foram adquiridos, em diferentes pontos da conduta, valores de pressão do escoamento gasoso. A partir destes valores e da lei de Darcy, foi possível obter valores de permeabilidade para a matriz em questão de 5,0 10-8 a 2,9 10-7 m2, para orientação longitudinal, e 1,0 10-8 a 1,3 10-7 m2 para orientação radial.
Solar energy has still an enormous potential to explore, especially in Portugal. However, this kind of energy has drawbacks such as its intermittency and large regional variations. So, it is necessary to improve the technological systems particularly with regard to efficiency. The main objective of this dissertation is the characterization of a porous metal matrix, known as “steel wool”, to be used as an absorber on a flat-plate collector. Thermal and dynamic interactions between the matrix and a gas flow (air) were studied, for different air flow rates, porosities and spatial orientation of the matrix. An experimental installation and a mathematical theoretical model were used to obtain the values reported. The comparison between experimental and modeled values allowed to obtain heat transfer coefficients from 10 to 70 W.m-2.˚C-1 for a radial orientation of the matrix, and from 10 to 90 W.m-2.˚C-1, for a longitudinal orientation. The same experimental installation was used to determine the pressure drop and the matrix permeability. Using the Darcy's law, it was possible to obtain a range of permeability values from 5 10-8 to 2,9 10-7 m2, for longitudinal orientation, and 1 10-8 to 1,3 10-7 m2, for radial orientation of the matrix.
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Goel, Vinod Kumar. "Some studies on normal and reverse flat plate collectors." Thesis, 1988. http://localhost:8080/xmlui/handle/12345678/6363.
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Lin, Chi-Yen, and 林其諺. "The Optimum Design of Improved Flat-Plate Solar Air Heaters." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/92150131281856006605.
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碩士淡江大學
化學工程研究所
83
The main applications of solar air heaters are drying and space heating. Many designs of solar air heaters have been i- nvestigated in improving the efficiency. There are many fact- ors influencing solar air heaters efficiency, such as the co- figation of absorber and the design of air duct. This study investigates the effects of aspect ratio of a rectangular flat- plate collector and area ratio of a divided collector on the collector efficiency, under constant collec- tor area and constant flow rate. Five collector types were considered in this study. They are the collectors (a)with fl- ow over absorber, (b)with downward fin, (c)with upward fin, (d)with downward fin attached by baffles, and (e)with upward fin attached by baffles. In first section, the results indicated that the collect- or efficiency increases when collector aspect ratio increases . In second section, it was found that the efficiency is imp- roved when the collector is divided into two component and t- he optimum area ratio is unity.
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Mesquita, Lucio Cesar De Souza. "Analysis of a Flat-Plate, Liquid-Desiccant, Dehumidifier and Regenerator." Thesis, 2007. http://hdl.handle.net/1974/977.
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A numerical model for isothermal and non-isothermal flat-plate liquid-desiccant dehumidifiers and regenerators was developed and implemented. The two-dimensional model takes into account the desiccant, water and air flow streams. A parametric analysis was performed to evaluate the influence of some of the most important operational parameters on mass transfer performance, such as flow configuration, water mass flow rate and inlet temperature, and desiccant mass flow rate. The results indicate that the water temperature and mass flow rate have a strong effect on the performance of the dehumidifier and regenerator, with the isothermal wall case acting as an upper limiting case. Increasing the desiccant mass flow rate improves the water transfer performance, but the improvement is asymptotic with mass flow rate.
An experimental rig with a single channel prototype was also built and tests were run for 18 different cases, with varying water mass flow rate, desiccant mass flow rate and flow configuration. The results show trends similar to those observed in the numerical results. However, the discrepancies between the numerical and experimental results are larger than the estimated experimental uncertainty at a 95% confidence level. There is some indication that poor desiccant wetting of the channel walls was partially responsible for the discrepancies.Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2007-12-31 22:12:39.184
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Chao, I.-Jen, and 趙一任. "Performance Evaluation on Solar Collectors integrating with Double-layer Roof Construction from Energy-saving Perspective–A Case of Flat Roof Construction." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/8cwe3f.
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碩士國立臺北科技大學
建築與都市設計研究所
94
There is no doubt that solar energy, which is clean and non-hazardous, could contribute considerably to a solution of the energy problem if appropriate method is developed to collect, concentrate, store and convert solar radiation which is diffuse and intrinsically intermittent. Especially in Taiwan, people suffer from the heat between May to October. During this period, solar radiation of horizontal plane is two to three times comparing with vertical ones. The heat causing by solar radiation results in interior space hardly achieving the requirement of comfort. This study develops a double-layer roof with a layer of air inside insulation interior space from heat to reduce energy consumption. Moreover, solar collector in the shape of net is embedded in the double-layer roof. The device, a concrete solar collector, collects in solar energy for heating water. The surface of roof, which directly contacts solar radiation, becomes a multi-function fabric of heat insulation and collector. It reduces the interior heat load and gaining the possibility of energy recycle. The study demonstrates a new idea of forming familiar materials and evaluates the performance by real case. It also conducts an analysis on the performance of double-layer roof and concrete solar collector. According to the result, it evidences that the proposed device actually benefits in heat insulation, reducing 36.93% to 84.64% of the coefficient of heat transmission comparing with single layer roof of RC. In addition, the proposed device also has good performance in heat collection. The experiment illustrates the temperature can be accepted for bath. Most roof design doesn’t take the function of heat insulation into consideration until now. Based on the limitation of registration on the roof and calamity prevention, the study provides a practical mechanism which integrating concrete and solar collectors from energy-saving perspective.
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Huang, Jun-Wei, and 黃君維. "The Heat-Transfer Efficiency Improvement of Flat-Plate Solar Hybrid Photovoltaic/Thermal Systems with Single- and Multi-Pass Rectangular Flow ducts." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/72407401384050365096.
Full textAbstract:
碩士淡江大學
化學工程與材料工程學系碩士班
96
The new solar hybrid photovoltaic/thermal (PV/T) system with multi-pass rectangular flow ducts is designed to improve the overall efficiency of thermal heat-transfer efficiency and PV cell efficiency. The theoretical formulations of the solar hybrid PV/T system are developed by making the energy balance and the resultant equations are solved by the fourth-order Runge–Kutta method. The factors affecting the device performance are the numbers of flow ducts, air mass flow rate, inlet air temperature and incident solar radiation. The theoretical results indicate that the heat transfer efficiency of solar air heater and solar hybrid PV/T systems increases with increasing the numbers of the rectangular flow ducts and air mass flow rate but decreasing with the incident solar radiation and inlet air temperature. The experimental apparatus of flat-plate solar air heaters and solar hybrid PV/T systems are also set up to confirm the accuracy of the theoretical predictions. The comparison between the theoretical predictions and experimental results shows that the good agreement is achieved in the present study.
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Almeida, Sérgio Miguel Carvalho de. "Otimização de um coletor solar plano com base no princípio constructal." Master's thesis, 2017. http://hdl.handle.net/10316/83107.
Full textAbstract:
Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e TecnologiaO desenvolvimento de geometrias de coletores solares planos não obteve qualquer evolução nos últimos anos, estando generalizada uma só solução para a circulação do fluido no seu interior.No âmbito da otimização destes sistemas procurou-se desenvolver uma metodologia inovadora de dimensionamento da geometria da tubagem que minimize a queda de pressão, enquanto estabelece linhas orientadoras para maximizar a transferência de calor entre a radiação solar absorvida e o escoamento no interior dos tubos do coletor. O princípio constructal foi validado como ferramenta de dimensionamento com a sua aplicação a um coletor solar dito convencional, com uma rede de tubos paralelos. A ferramenta constructal desenvolvida é aplicada com o intuito de melhorar o comportamento hidrodinâmico do coletor solar, resultando num valor ótimo quer do número de tubos, quer do espaçamento entre estes, tendo como constrangimento a largura do coletor solar. A ferramenta demonstra como o princípio prevê o que se considera como otimizado no mercado.Posteriormente estudaram-se duas novas disposições da rede de tubos do coletor, obtendo assim duas estruturas dendríticas, uma radial e uma linha-até-linha, sendo que estas têm configurações para a rede bastante diferentes daquela que atualmente se encontra presente no mercado.Os estudos teóricos levam a que se possa prever que um sistema constructal irá permitir um aproveitamento da energia proveniente do sol aproximadamente igual aquele que se consegue com um coletor solar convencional, mas com duas grandes vantagens. A área do coletor é reduzida para metade daquela apresentada para um coletor solar convencional, ou seja, irá haver um gasto muito inferior de material assim como uma redução do peso das estruturas. A aplicação da ferramenta constructal indica uma redução da queda de pressão em cerca de 67,5\% para uma rede radial de diâmetros constantes, de 77,7\% para um rede radial de diâmetros variáveis e de 71,2\% para uma rede linha-até-linha com diâmetros variáveis, isto em comparação com um coletor solar convencional com a mesma área que a área que um coletor constructal. A análise experimental de um sistema radial com diâmetros constantes corrobora os resultados obtidos teoricamente.O uso do princípio constructal como uma ferramenta de design otimizado de sistemas está ainda em vias de desenvolvimento. Pretende-se no futuro continuar a desenvolver a ferramenta para a produção de novas geometrias de coletores solares cada vez mais eficientes.
Flat plate solar collector’s geometries development has not evolved much in the last few years. Almost all systems use the same solution for internal flow.The scope of this thesis is optimizing these systems using a new method developed for defining pipe geometry design. This method, based on the constructal principle, seeks to find the optimal conditions for minimizing pressure drop, while establishing a tool to maximize heat transfer between the absorbed solar radiation and the flow inside the tubes.The constructal principle is validated as a design tool being applied to a conventional flat plate solar collector, with a parallel pipe network configuration. The constructal tool developed is applied with the purpose of optimizing the solar collector hydrodynamic behaviour. Resulting in an optimal number of pipes and spacing between them, using the width of the collector as a constraint. The tool demonstrates how the principle predicts what the market considers as optimized. Posteriorly, new solutions based on dendritic structures with network configurations are explored, obtaining two dendritic structures, one radial and one line-to-line, with quite different geometries from those currently found on the market. Theoretical studies show that it can be predict that a constructal system will allow an exploitation of the energy supplied by the sun similar to the conventional approach, with two major improvements. Constructal collection area is half the conventional one, meaning that less material is required, and the weigth of the structures is also reduced.Applying the constructal tool indicates a pressure drop reduction of 67,5\% for a radial network with constant diameters, of 77,7\% for a radial network with variable diameters and 71,2\% for a line-to-line network with variable diameters. This, comparing with a conventional collector of the same size as the constructal one. The experimental analysis of a radial system with constant diameters corroborates the theoretical results obtained.The use of the constructal principel as a design tool of solar panels is still under development, and future work considers the impact of the approach in the obtaining more efficient geometries for solar panels.