Dissertations / Theses: 'Concentrating systems'

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Buie, Damien Charles William. "Optical considerations in solar concentrating systems." University of Sydney. Physics, 2004. http://hdl.handle.net/2123/587.

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To optimise the performance of concentrating solar power systems, a detailed knowledge of the resultant flux distribution in the imaging plane is required. To achieve this, an accurate model of the direct solar beam impinging on the concentrator is essential. This thesis presents an empirical model of the terrestrial solar distribution that has both a high-correlation to observed data and an invariance to a change in location. The model is based on the amount of circumsolar radiation in the direct beam and takes into account the small variations that are due to atmospheric scattering. A modelling framework is developed to simulate the flux distribution in the imaging plane of a generic solar concentrating system. Algorithms are developed to include the following: the spatial solar energy distribution; the systemic effect of reflecting that distribution off a non-ideal mirrored surface; the spectral energy distribution; the transmission, absorption and reflection characteristics of optical thin films; and the coordinates of the solar vector. The framework is then used to investigate the performance of anti-reflection coatings on silicon substrates and the performance of linear Fresnel systems. Combined, these algorithms and simulation tools can be applied to create comprehensive optical models of solar concentrating systems.

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Buie, Damien Charles William. "Optical considerations in solar concentrating systems." Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/587.

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Abstract:

To optimise the performance of concentrating solar power systems, a detailed knowledge of the resultant flux distribution in the imaging plane is required. To achieve this, an accurate model of the direct solar beam impinging on the concentrator is essential. This thesis presents an empirical model of the terrestrial solar distribution that has both a high-correlation to observed data and an invariance to a change in location. The model is based on the amount of circumsolar radiation in the direct beam and takes into account the small variations that are due to atmospheric scattering. A modelling framework is developed to simulate the flux distribution in the imaging plane of a generic solar concentrating system. Algorithms are developed to include the following: the spatial solar energy distribution; the systemic effect of reflecting that distribution off a non-ideal mirrored surface; the spectral energy distribution; the transmission, absorption and reflection characteristics of optical thin films; and the coordinates of the solar vector. The framework is then used to investigate the performance of anti-reflection coatings on silicon substrates and the performance of linear Fresnel systems. Combined, these algorithms and simulation tools can be applied to create comprehensive optical models of solar concentrating systems.

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Baig, Hasan. "Enhancing performance of building integrated concentrating photovoltaic systems." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/17301.

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Buildings both commercial and residential are the largest consumers of electricity. Integrating Photovoltaic technology in building architecture or Building Integrated Photovoltaics (BIPV) provides an effective means for meeting this huge energy demands and provides an energy hub at the place of its immediate requirement. However, this technology is challenged with problems like low efficiency and high cost. An effective way of improving the solar cell efficiency and reducing the cost of photovoltaic systems is either by reducing solar cell manufacturing cost or illuminating the solar cells with a higher light intensity than is naturally available by the use of optical concentrators which is also known as Concentrating Photovoltaic (CPV) technology. Integrating this technology in the architecture is referred as Building integrated Concentrating Photovoltaics (BICPV). This thesis presents a detailed performance analysis of different designs used as BICPV systems and proposes further advancements necessary for improving the system design and minimizing losses. The systems under study include a Dielectric Asymmetric Compound Parabolic Concentrator (DiACPC) designed for 2.8×, a three-dimensional Cross compound parabolic concentrator (3DCCPC) designed for 3.6× and a Square Elliptical Hyperbolic (SEH) concentrator designed for 6×. A detailed analysis procedure is presented showcasing the optical, electrical, thermal and overall analysis of these systems. A particular issue for CPV technology is the non-uniformity of the incident flux which tends to cause hot spots, current mismatch and reduce the overall efficiency of the system. Emphasis is placed on modelling the effects of non-uniformity while evaluating the performance of these systems. The optical analysis of the concentrators is carried out using ray tracing and finite element methods are employed to determine electrical and thermal performance of the system. Based on the optical analysis, the outgoing flux from the concentrators is predicted for different incident angles for each of the concentrators. A finite element model for the solar cell was developed to evaluate its electrical performance using the outputs obtained from the optical analysis. The model can also be applied for the optimization of the front grid pattern of Si Solar cells. The model is further coupled within the thermal analysis of the system, where the temperature of the solar cell is predicted under operating conditions and used to evaluate the overall performance under steady state conditions. During the analysis of the DiACPC it was found that the maximum cell temperature reached was 349.5 K under an incident solar radiation of 1000 W/m2. Results from the study carried on the 3DCCPC showed that a maximum cell temperature of 332 K is reached under normal incidence, this tends to bring down the overall power production by 14.6%. In the case of the SEH based system a maximum temperature of 319 K was observed on the solar cell surface under normal incidence. An average drop of 11.7% was found making the effective power ratio of the system 3.4. The non-uniformity introduced due to the concentrator profile causes hotspots in the BICPV system. The non-uniformity was found to reduce the efficiency of the solar cell in the range of 0.5-1 % in all the three studies. The overall performance can be improved by addressing losses occurring within different components of the system. It was found that optical losses occurred at the interface region formed due to the encapsulant spillage along the edges of the concentrator. Using a reflective film along the edge of the concentrating element was found to improve the optical efficiency of the system. Case studies highlighting the improvement are presented. A reflective film was attached along the interface region of the concentrator and the encapsulant. In the case of a DiACPC, an increase of 6% could be seen in the overall power production. Similar case study was performed for a 3DCCPC and a maximum of 6.7% was seen in the power output. To further improve the system performance a new design incorporating conjugate reflective-refractive device was evaluated. The device benefits from high optical efficiency due to the reflection and greater acceptance angle due to refraction. Finally, recommendations are made for development of a new generation of designs to be used in BiCPV applications. Efforts are made towards improving the overall performance and reducing the non-uniformity of the concentrated illumination.

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Coventry, Joseph Sydney. "A solar concentrating photovoltaic/thermal collector /." View thesis entry in Australian Digital Theses Program, 2004. http://thesis.anu.edu.au/public/adt-ANU20041019.152046/index.html.

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Morfeldt, Johannes. "Optically Selective Surfaces in low concentrating PV/T systems." Thesis, Örebro University, School of Science and Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-7396.

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One of the traditional approaches to reduce costs of solar energy is to use inexpensive reflectors to focus the light onto highly efficient solar cells. Several research projects have resulted in designs, where the excess heat is used as solar thermal energy.Unlike a solar thermal system, which has a selective surface to reduce the radiant heat loss, a CPV/T (Concentrating PhotoVoltaic/Thermal) system uses a receiver covered with solar cells with high thermal emittance.This project analyzes whether the heat loss from the receiver can be reduced by covering parts of the receiver surface, not already covered with solar cells, with an optically selective coating. Comparing different methods of applying such a coating and the long-term stability of low cost alternatives are also part of the objectives of this project.To calculate the heat loss reductions of the optically selective surface coating a mathematical model was developed, which takes the thermal emittances and the solar absorptances of the different surfaces into account. Furthermore, a full-size experiment was constructed to verify the theoretical predictions.The coating results in a heat loss reduction of approximately 20 % in such a CPV/T system and one of the companies involved in the study is already changing their design to make use of the results.

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Gasti, Maria. "Techno-economic Appraisal of Concentrating Solar Power Systems (CSP)." Thesis, Högskolan Dalarna, Energi och miljöteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:du-12806.

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The diffusion of Concentrating Solar Power Systems (CSP) systems is currently taking place at a much slower pace than photovoltaic (PV) power systems. This is mainly because of the higher present cost of the solar thermal power plants, but also for the time that is needed in order to build them. Though economic attractiveness of different Concentrating technologies varies, still PV power dominates the market. The price of CSP is expected to drop significantly in the near future and wide spread installation of them will follow. The main aim of this project is the creation of different relevant case studies on solar thermal power generation and a comparison betwwen them. The purpose of this detailed comparison is the techno-economic appraisal of a number of CSP systems and the understanding of their behaviour under various boundary conditions. The CSP technologies which will be examined are the Parabolic Trough, the Molten Salt Power Tower, the Linear Fresnel Mirrors and the Dish Stirling. These systems will be appropriatly sized and simulated. All of the simulations aim in the optimization of the particular system. This includes two main issues. The first is the achievement of the lowest possible levelized cost of electricity and the second is the maximization of the annual energy output (kWh). The project also aims in the specification of these factors which affect more the results and more specifically, in what they contribute to the cost reduction or the power generation. Also, photovoltaic systems will be simulated under same boundary conditions to facolitate a comparison between the PV and the CSP systems. Last but not leats, there will be a determination of the system which performs better in each case study.

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Nguyen, Tam Thanh. "Concentrating Solar Thermal Energy Storage Using Amide-Hydride Systems." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59669.

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Amide-hydride systems can be used in thermal storage systems by taking advantage of their endothermic/exothermic reactions with hydrogen. This allows the harnessing of concentrated solar energy by utilising thermal storage to alleviate its intermittent nature. Amide-hydride reactions have been widely studied for their low temperature applications. However, the high temperature imide-hydride reactions are more suitable for thermal energy storage. Lithium, magnesium and calcium-based amide-imide-hydride systems were investigated with potential candidates from systems containing calcium metal.

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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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Brogren, Maria. "Optical Efficiency of Low-Concentrating Solar Energy Systems with Parabolic Reflectors." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3988.

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Paul, Damasen Ikwaba. "Characterisation of solar concentrating systems for photovoltaics and their impact on performance." Thesis, University of Ulster, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549700.

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The use of concentrating systems has a great potential to become the lowest-cost PV option if the high energy flux in the concentrated PV module can be utilised efficiently. In this study, a PV module with isolated cells was designed and fabricated with the purpose of examining the performance of each cell under concentrated (using CPC and V-trough) and non-concentrated light. Before the experimental characterisation, a detailed optical analysis for the CPC and V-trough collectors was undertaken. It was found that in spite of both concentrators having the same concentration ratio and aperture area, the angular acceptance and optical efficiency for the CPC were always higher than those of the V-trough for incidence angles above ± 20° and ± 10° , respectively. A comparison of flux distribution on the absorber of the two concentrators indicated that the energy flux was more uniform in the V -trough collector than in the CPC collector. The experimental energy flux concentration for the CPC collector (at normal incidence angle) varied from 0.9 to 3.6, with higher irradiance concentrated near the edges of the PV module. As a result, the CPC performed better with cells located near the edges of the PV module than those at the centre. On the other hand, the energy concentration for the V -trough collector varied from 1.3 to 2.5, with higher irradiance concentrated at the centre of the PV module. The use of the CPC and V-trough concentrators increased the power output of a PV module by 25% and 46%, respectively, compared to a similar non-concentrated PV module. The fabricated isolated cells PV module was used to evaluate, theoretically and experimentally, the energy flux distribution on the surface of a concentrated PV module under CPC and V -trough concentrators. From the analysis, it was found that in both collectors, the experimental optical efficiency (indoor and outdoor) results follow the theoretical ones with reasonable accuracy, especially the outdoor experimental results. The comparison between outdoor and indoor experimental optical efficiencies in each collector showed that there was good agreement between the two results, both for low and high incidence angles. The effects of non-uniform illumination on the performance of a single standard PV cell, at low and medium energy flux concentration ratios as well as the effect of orientation, size and geometrical shapes of non-uniform illumination were studied. It was found that the effect of non-uniform illumination on various cell performance parameters becomes noticeable at medium energy flux concentration ratio. The results also indicated that the performance of a single conventional PV cell depends neither on the location and size of the non-uniform illumination nor the geometrical shape of the non-uniform illumination. A novel hybrid PV cell consisting of low and high efficiency PV cells was designed and fabricated. The electrical energy produced by the hybrid cell was compared, theoretically and experimentally, with a similar low efficiency single PV (LESPV) cell in a low- concentrating symmetric CPC suitable for facade, sloping roof, flat roof and rear side building integration. Both results, simulation and experimental, showed that the daily electrical energy produced by a hybrid cell for different Belfast (UK) sky conditions was higher than that of the LESPV cell, but not to the expected value.

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Yandt, Mark. "Characterization and Performance Analysis of High Efficiency Solar Cells and Concentrating Photovoltaic Systems." Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20535.

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As part of the SUNRISE project (Semiconductors Using Nanostructures for Record Increases in Solar-cell Efficiency), high efficiency, III-V semiconductor, quantum-dot-enhanced, triple-junction solar cells designed and manufactured by Cyrium Technologies Inc. were integrated into OPEL Solar, MK-I, Fresnel-lens-based, 550x concentrating modules carried on a dual axis tracker. Over its first year of operation 1.8 MWh of AC electrical energy was exported to the grid. Measurements of the direct and indirect components of the insolation, as well as the spectral irradiance of light incident on the demonstrator in Ottawa, Canada are presented. The system efficiency is measured and compared to that predicted by a system model to identify loss mechanisms so that they can be minimized in future deployments.

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Menoufi, Karim Ali Ibrahim. "Life Cycle Assessment of novel Building Integrated Concentrating Photovoltaic systems through environmental and energy evaluations." Doctoral thesis, Universitat de Lleida, 2014. http://hdl.handle.net/10803/131056.

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La realització d'estudis de LCA per a sistemes fotovoltaics és una eina essencial per mesurar el seu nivell de sostenibilitat En aquest sentit, i després de la realització d' una anàlisi teòrica dels estudis publicats de LCA dels sistemes fotovoltaics, s'han trobat algunes llacunes. Aquestes llacunes es refereixen a la manca de varietat d'indicadors de LCA, on la majoria dels estudis depenen del temps de retorn energètic, sent aquest gairebé l'únic indicador (no es té en compte l'ús dels mètodes de perfil ambiental). A més, s'observen dues bretxes relatives a la manca d'estudis de LCA destacant la integració en edificis d'energia solar d'una banda, i l'ús de la tecnologia fotovoltaica de concentració per un altre. Per tant, en aquesta tesi, es presenta una nova aportació al camp dels estudis LCA dels sistemes fotovoltaics integrats en edificis. Això s'aconsegueix a través de l'avaluació ambiental i energètica dels sistemes de concentració fotovoltaica integrats en edificis (BICPV). Els resultats es presenten en termes de metodologies d'avaluació de l' impacte del cicle de vida (perfil mediambiental), així com el temps d'amortització de l'Energia i el Factor de Retorn (perfil energètic). Els resultats, amb el suport de les anàlisis de sensibilitat i la comparació amb un sistema convencional fotovoltaic per a integració en edificis (BIPV), mostren beneficis ambientals significatius que poden ser obtinguts a través de sistemes BICPV. A Finalment, es discuteixen les recomanacions per a treballs i millores futures. Conducting LCA studies for PV systems is an essential tool for measuring the sustainability level of a corresponding system. In this sense, and after conducting a theoretical analysis of the LCA studies of PV systems in literature within the context of energy generation, some gaps have been found. These gaps are briefly represented in the lack of variety of LCA indicators, where most of the studies are dependent on the Energy Payback Time as almost the sole environmental indicator, disregarding the use of environmental profile methods. In addition, another two gaps are observed concerning the lack of LCA studies highlighting the building integration from one side, and the use of the concentrating PV technology from another side. Hence, in this thesis, a novel contribution to the field of LCA studies of PV systems is presented. This is achieved through environmentally and energetically evaluating novel Building Integrated Concentrating Photovoltaic (BICPV) systems. The results are presented in terms of Life Cycle Impact Assessment methodologies (environmental profile), as well as the Energy Payback Time and the Energy Return Factor (Energy profile). The results, supported by sensitivity analyses and comparison to a conventional Building Integrated Photovoltaic (BIPV) system, show the significant environmental benefits that can be acquired through BICPV systems. Finally, recommendations for future work and improvements are discussed as well. La realización de estudios de LCA para sistemas fotovoltaicos es una herramienta esencial para medir su nivel de sostenibilidad. En este sentido, y después de la realización de un análisis teórico de los estudios de LCA de los sistemas fotovoltaicos en la literatura en el contexto de la generación de energía, se han encontrado algunas lagunas. Algunas de estas lagunas se refieren: la falta de variedad de indicadores de LCA, donde la mayoría de los estudios dependen del tiempo de retorno energético, siendo este casi el único indicador medioambiental (no se tiene en cuenta el uso de los métodos de perfil medioambiental). Además, se observan otras dos brechas relativas a la falta de estudios de LCA destacando la integración en edificios de energía solar por un lado, y el uso de la tecnología fotovoltaica de concentración por otro. Por lo tanto, en esta tesis, se presenta una nueva aportación al campo de los estudios LCA de los sistemas fotovoltaicos integrados en edificios. Esto se logra a través de la evaluación medioambiental y energética de los sistemas de concentración fotovoltaica integrados en edificios (BICPV). Los resultados se presentan en términos de metodologías de evaluación del impacto del ciclo de vida (perfil medioambiental), así como el tiempo de amortización de la Energía y su Factor de Retorno (perfil de la Energía). Los resultados, con el apoyo de los análisis de sensibilidad y la comparación con un sistema convencional fotovoltaico para integración en edificios (BIPV), muestran beneficios ambientales significativos que pueden ser obtenidos a través de sistemas BICPV. Finalmente, se discuten las recomendaciones para trabajos y mejoras futuros.

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Colby, Aaron Henry. "Novel drug delivery systems: pH-responsive expansile nanoparticles & drug concentrating devices as tools for treating cancer." Thesis, Boston University, 2008. https://hdl.handle.net/2144/30651.

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Thesis (Ph.D.)--Boston University New strategies for treatment and methods of drug delivery are required for patients suffering from cancer-the second leading cause of death worldwide. Current chemotherapeutic treatments frequently suffer from poor water solubility, systemic toxicity, poor accumulation within the target tissues and an inability to eradicate all remaining tumor following resection procedures. Nanoparticles (NPs) are extensively investigated as a means to increase drug solubility, alter biodistribution, target specific sites within the body, and minimize drug side effects and, as such, numerous NP formulations are being investigated as drug delivery devices to assist in the treatment and management of cancer. We have developed a pH-responsive expansile nanoparticle (eNP) that can encapsulate the hydrophobic chemotherapeutic agent Paclitaxel (Pax) (a poorly water soluble, yet potent chemotherapeutic agent), and deliver it specifically to the intracellular compartment of tumor cells. Paclitaxel-loaded-eNPs (Pax-eNPs) localize specifically to regions of intraperitoneal (IP) tumors and, once taken up by tumor cells, undergo a conformational change upon exposure to the mildly acidic cellular endosome that results in eNP swelling and intratumoral drug release. In this work, we describe: 1) the clinical problem and cost (both humanitarian and fmancial) of local cancer recurrence following tumor resection; 2) the eNP delivery system and, specifically, we characterize the swelling of eNPs using microscopy and tunable resistive pulse sensing techniques; 3) the in vitro activity of Pax-eNPs in breast cancer cells; 4) the improved efficacy of Pax- eNPs compared to the standard clinical formulation of Pax (i.e., Pax dissolved in Cremophor/Ethanol) in a murine model of established peritoneal mesothelioma; and, 5) the ability of eNPs to act as intratumoral, intracellular drug concentrating devices. Further investigation of this NP-based drug delivery system will facilitate a greater understanding of the materials and devices used in the delivery of chemotherapeutic agents and may lead to the clinical translation and application of eNPs. 2019-05-01

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Duanmu, Deqiang. "Putative inorganic carbon transport and accumulation systems associated with the CO₂ concentrating mechanism in Chlamydomonas reinhardtii." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3373459.

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Nordlander, Svante. "Load Adapted Solar Thermal Combisystems - Optical Analysis and Systems Optimization." Licentiate thesis, Högskolan Dalarna, Miljöteknik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:du-1020.

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In a northern European climate a typical solar combisystem for a single family house normally saves between 10 and 30 % of the auxiliary energy needed for space heating and domestic water heating. It is considered uneconomical to dimension systems for higher energy savings. Overheating problems may also occur. One way of avoiding these problems is to use a collector that is designed so that it has a low optical efficiency in summer, when the solar elevation is high and the load is small, and a high optical efficiency in early spring and late fall when the solar elevation is low and the load is large.The study investigates the possibilities to design the system and, in particular, the collector optics, in order to match the system performance with the yearly variations of the heating load and the solar irradiation. It seems possible to design practically viable load adapted collectors, and to use them for whole roofs ( 40 m2) without causing more overheating stress on the system than with a standard 10 m2 system. The load adapted collectors collect roughly as much energy per unit area as flat plate collectors, but they may be produced at a lower cost due to lower material costs. There is an additional potential for a cost reduction since it is possible to design the load adapted collector for low stagnation temperatures making it possible to use less expensive materials. One and the same collector design is suitable for a wide range of system sizes and roof inclinations. The report contains descriptions of optimized collector designs, properties of realistic collectors, and results of calculations of system output, stagnation performance and cost performance. Appropriate computer tools for optical analysis, optimization of collectors in systems and a very fast simulation model have been developed.

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Colby, Aaron Henry. "Novel drug delivery systems: pH-responsive expansile nanoparticles & drug concentrating devices as tools for treating cancer." Thesis, Boston University, 2014. https://hdl.handle.net/2144/12957.

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Thesis (Ph.D.)--Boston University New strategies for treatment and methods of drug delivery are required for patients suffering from cancer-the second leading cause of death worldwide. Current chemotherapeutic treatments frequently suffer from poor water solubility, systemic toxicity, poor accumulation within the target tissues and an inability to eradicate all remaining tumor following resection procedures. Nanoparticles (NPs) are extensively investigated as a means to increase drug solubility, alter biodistribution, target specific sites within the body, and minimize drug side effects and, as such, numerous NP formulations are being investigated as drug delivery devices to assist in the treatment and management of cancer. We have developed a pH-responsive expansile nanoparticle (eNP) that can encapsulate the hydrophobic chemotherapeutic agent Paclitaxel (Pax) (a poorly water soluble, yet potent chemotherapeutic agent), and deliver it specifically to the intracellular compartment of tumor cells. Paclitaxel-loaded-eNPs (Pax-eNPs) localize specifically to regions of intraperitoneal (IP) tumors and, once taken up by tumor cells, undergo a conformational change upon exposure to the mildly acidic cellular endosome that results in eNP swelling and intratumoral drug release. In this work, we describe: 1) the clinical problem and cost (both humanitarian and fmancial) of local cancer recurrence following tumor resection; 2) the eNP delivery system and, specifically, we characterize the swelling of eNPs using microscopy and tunable resistive pulse sensing techniques; 3) the in vitro activity of Pax-eNPs in breast cancer cells; 4) the improved efficacy of Pax- eNPs compared to the standard clinical formulation of Pax (i.e., Pax dissolved in Cremophor/Ethanol) in a murine model of established peritoneal mesothelioma; and, 5) the ability of eNPs to act as intratumoral, intracellular drug concentrating devices. Further investigation of this NP-based drug delivery system will facilitate a greater understanding of the materials and devices used in the delivery of chemotherapeutic agents and may lead to the clinical translation and application of eNPs.

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Gaynullin, Bakhram. "LASER-TESTING RIG : Measurement System for evaluation of Shape of concentrating reflector for solar collector Absolicon X10." Thesis, Högskolan Dalarna, Energi och miljöteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:du-4645.

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This Thesis project is a part of the all-round automation of production of concentrating solar PV/T systems Absolicon X10. ABSOLICON Solar Concentrator AB has been invented and started production of the prospective solar concentrated system Absolicon X10. The aims of this Thesis project are designing, assembling, calibrating and putting in operation the automatic measurement system intended to evaluate the shape of concentrating parabolic reflectors.On the basis of the requirements of the company administration and needs of real production process the operation conditions for the Laser testing rig were formulated. The basic concept to use laser radiation was defined.At the first step, the complex design of the whole system was made and division on the parts was defined. After the preliminary conducted simulations the function and operation conditions of the all parts were formulated.At the next steps, the detailed design of all the parts was conducted. Most components were ordered from respective companies. Some of the mechanical components were made in the workshop of the company. All parts of the Laser-testing rig were assembled and tested. Software part, which controls the Laser-testing rig work, was created on the LabVIEW basis. To tune and test software part the special simulator was designed and assembled.When all parts were assembled in the complete system, the Laser-testing rig was tested, calibrated and tuned.In the workshop of Absolicon AB, the trial measurements were conducted and Laser-testing rig was installed in the production line at the plant in Soleftea.

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Wang, Wujun. "Development of an Impinging Receiver for Solar Dish-Brayton Systems." Doctoral thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177531.

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A new receiver concept utilizing impinging jet cooling technology has been developed for a small scale solar dish-Brayton system. In a typical impinging receiver design, the jet nozzles are distributed evenly around the cylindrical absorber wall above the solar peak flux region for managing the temperature at an acceptable level. The absorbed solar irradiation is partially lost to the ambient by radiation and natural convection heat transfer, the major part is conducted through the wall and taken away by the impingement jets to drive a gas turbine. Since the thermal power requirement of a 5 kWe Compower® micro gas turbine (MGT) perfectly matches with the power collected by the EuroDish when the design Direct Normal Irradiance (DNI) input is 800 W/m2, the boundary conditions for the impinging receiver design in this work are based on the combination of the Compower®MGT and the EuroDish system. In order to quickly find feasible receiver geometries and impinging jet nozzle arrangements for achieving acceptable temperature level and temperature distributions on the absorber cavity wall, a novel inverse design method (IDM) has been developed based on a combination of a ray-tracing model and a heat transfer analytical model. In this design method, a heat transfer model of the absorber wall is used for analyzing the main heat transfer process between the cavity wall outer surface, the inner surface and the working fluid. A ray-tracing model is utilized for obtaining the solar radiative boundary conditions for the heat transfer model. Furthermore, the minimum stagnation heat transfer coefficient, the jet pitch and the maximum pressure drop governing equations are used for narrowing down the possible nozzle arrangements. Finally, the curves for the required total heat transfer coefficient distribution are obtained and compared with different selected impinging arrangements on the working fluid side, and candidate design configurations are obtained. Furthermore, a numerical conjugate heat transfer model combined with a ray-tracing model was developed validating the inverse design method and for studying the thermal performance of an impinging receiver in detail. With the help of the modified inverse design method and the numerical conjugate heat transfer model, two impinging receivers based on sintered α-SiC (SSiC) and stainless steel 253 MA material have been successfully designed. The detailed analyses show that for the 253 MA impinging receiver, the average air temperature at the outlet and the thermal efficiency can reach 1071.5 K and 82.7% at a DNI level of 800 W/m2 matching the system requirements well. Furthermore, the local temperature differences on the absorber can be reduced to 130 K and 149 K for two different DNI levels, which is a significant reduction and improvement compared with earlier published cavity receiver designs. The inverse design method has also been verified to be an efficient way in reducing the calculation costs during the design procedure. For the validation and demonstration of the receiver designs, a unique experimental facility was designed and constructed. The facility is a novel high flux solar simulator utilizing for the first time Fresnel lenses to concentrate the light of 12 commercial high power Xenon-arc lamps. Finally, a prototype of a 253 MA based impinging was experimentally studied with the help of the 84 kWe Fresnel lens based high flux solar simulator in KTH. QC 20151123 Optimised Microturbine Solar Power System , OMSOP

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19

Trahan, Jamie. "A Technical and Economic Comparative Analysis of Sensible and Latent Heat Packed Bed Storage Systems for Concentrating Solar Thermal Power Plants." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5598.

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Though economically favorable when compared to other renewable energy storage technologies, thermal energy storage systems for concentrating solar thermal power (CSP) plants require additional cost reduction measures to help transition CSP plants to the point of grid-parity. Thermocline packed bed storage is regarded as one potential low cost solution due to the single tank requirement and low cost storage media. Thus sensible heat storage (SHS) and latent heat storage (LHS) packed bed systems, which are two thermocline varieties, are frequently investigated. LHS systems can be further classified as single phase change material (PCM) systems or cascaded systems wherein multiple PCMs are employed. This study compared the performance of SHS, single PCM, and cascaded PCM direct storage systems under the conditions that may be encountered in utility-scale molten salt CSP plants operating between 565°C and 288°C. A small-scale prototype SHS packed bed system was constructed and operated for use in validating a numerical model. The drawbacks of the latent heat storage process were discussed, and cascaded systems were investigated for their potential in mitigating the issues associated with adopting a single PCM. Several cascaded PCM configurations were evaluated. The study finds that the volume fraction of each PCM and the arrangement of latent heat in a 2-PCM and a 3-PCM system influences the output of the system, both in terms of quality and quantity of energy. In addition to studying systems of hypothetical PCMs, real salt PCM systems were examined and their selection process was discussed. A preliminary economic assessment was conducted to compare the cost of SHS, single-PCM LHS, cascaded LHS, and state-of-the-art 2-tank systems. To the author's knowledge, this is the first study that compares the cost of all three thermocline packed bed systems with the 2-tank design. The SHS system is significantly lower in cost than the remaining systems, however the LHS system does show some economic benefit over the 2-tank design. If LHS systems are to be viable in the future, low cost storage media and encapsulation techniques are necessary.

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Schneider, Simon Verfasser], Robert [Akademischer Betreuer] Pitz-Paal, and Marek [Akademischer Betreuer] [Behr. "Influences of Mirror Shape Accuracy on Performance Prediction for Parabolic Trough Concentrating Solar Power Systems / Simon Schneider ; Robert Pitz-Paal, Marek Behr." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1162451440/34.

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21

COCCIA, GIANLUCA. "Design, Manufacturing, Testing, and Mathematical Modeling of Concentrating Solar Systems: a Study Applied to Prototypes of Parabolic Trough Collector and Solar Box Cooker." Doctoral thesis, Università Politecnica delle Marche, 2017. http://hdl.handle.net/11566/245262.

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L'utilizzo di energia solare termica deve essere sostenuto per ridurre il consumo di fonti fossili climalteranti. Nel presente studio si sono progettati e realizzati due sistemi solari a concentrazione: un collettore parabolico assiale (PTC) ed un forno solare a scatola. Il PTC ha un angolo di bordo di 90° ed un rapporto di concentrazione di 19,89. Sul concentratore, realizzato in sandwich composito, sono state applicate pellicole in alluminio ad elevata riflettanza. Il ricevitore è un tubo di acciaio rivestito da una vernice selettiva. Il sistema di inseguimento è governato da un algoritmo solare. I test sperimentali sono stati condotti con acqua ad una temperatura massima di 85 °C. Il PTC è stato caratterizzato ottenendo curve di efficienza termica, modificatore dell'angolo di incidenza e costante di tempo. I risultati mostrano che l'equazione dell'efficienza termica è confrontabile con quella di collettori simili. I dati sperimentali sono stati utilizzati per validare un ambiente di simulazione della resa annuale di PTC. Si è determinata la convenienza nell'adozione di nanofluidi a base di metalli rispetto al fluido di base (acqua). Sono state analizzate 5 temperature del fluido in ingresso e 3 portate in massa. I risultati mostrano che solo le nanoparticelle di Au, TiO2, ZnO e Al2O3 alle più basse concentrazioni presentano ridotti miglioramenti. Il forno solare a scatola ha un rapporto di concentrazione di 11,57, ed è costituito da una camera di cottura, un coperchio superiore vetrato e una doppia fila di specchi riflettenti. Il prototipo consente un allineamento solare manuale sia azimutale che zenitale. La temperatura massima del forno è stata determinata attraverso prove a vuoto. Sono state inoltre svolte prove a carico inserendo nel forno una o due pentole di alluminio, verniciate o meno in nero, riempite con acqua o olio di arachidi. In quest’ultimo caso, si è giunti a temperature superiori a 200 °C e a risultati confrontabili con quelli in letteratura. Use of solar thermal energy has to be sustained to reduce consumption of climate-changing fossil fuels. Thus, in this study two concentrating solar prototypes were designed and manufactured: a parabolic trough collector (PTC) and a solar box cooker. The PTC has a 90° rim angle and a concentration ratio of 19.89. The concentrator is a sandwich composite structure with high-reflectance aluminum foils applied on it. The receiver is a steel pipe painted with a selective coating. The tracking system is based on a solar-position computer program. Experimental tests were carried out with water and temperatures up to 85 °C. Thermal efficiency, incident angle modifier, and time constant curves were found. Results show that the thermal efficiency equation is comparable with that of other PTCs in literature. Experimental data were utilized to validate a simulation environment able to determine the yearly yield of PTCs. The simulation was carried out to evaluate the convenience in adopting metal-based nanofluids respect to the base fluid (water). Five inlet fluid temperatures and three mass flow rates were analyzed. Results show that only Au, TiO2, ZnO, and Al2O3 nanoparticles, at the lowest concentrations, present reduced improvements respect to water. The solar box cooker is a high concentration ratio prototype (11.57). The cooker has a cooking chamber with a glass cover on the top and is composed by two rows of booster mirrors. The prototype allows both an azimuth and a zenith manual orientation. Tests without load were carried out to evaluate the maximum cooker temperature. Tests with load, conduced using aluminum vessels containing a certain amount of water, were accomplished both with non-painted vessels and black-coated ones, and with one or two vessels. Additional tests were carried out with peanut oil. Using this fluid, temperatures higher than the water ones were achieved (> 200 °C) and results exhibited values comparable to those in literature.

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22

Xu, Ben. "Heat Transfer and Flow in Solar Energy and Bioenergy Systems." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/578616.

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The demand for clean and environmentally benign energy resources has been a great concern in the last two decades. To alleviate the associated environmental problems, reduction of the use of fossil fuels by developing more cost-effective renewable energy technologies becomes more and more significant. Among various types of renewable energy sources, solar energy and bioenergy take a great proportion. This dissertation focuses on the heat transfer and flow in solar energy and bioenergy systems, specifically for Thermal Energy Storage (TES) systems in Concentrated Solar Power (CSP) plants and open-channel algal culture raceways for biofuel production. The first part of this dissertation is the discussion about mathematical modeling, numerical simulation and experimental investigation of solar TES system. First of all, in order to accurately and efficiently simulate the conjugate heat transfer between Heat Transfer Fluid (HTF) and filler material in four different solid-fluid TES configurations, formulas of an eﬀective heat transfer coeﬃcient were theoretically developed and presented by extending the validity of Lumped Capacitance Method (LCM) to large Biot number, as well as verifications/validations to this simplified model. Secondly, to provide design guidelines for TES system in CSP plant using Phase Change Materials (PCM), a general storage tank volume sizing strategy and an energy storage startup strategy were proposed using the enthalpy-based 1D transient model. Then experimental investigations were conducted to explore a novel thermal storage material. The thermal storage performances were also compared between this novel storage material and concrete at a temperature range from 400 °C to 500 °C. It is recommended to apply this novel thermal storage material to replace concrete at high operating temperatures in sensible heat TES systems. The second part of this dissertation mainly focuses on the numerical and experimental study of an open-channel algae culture raceway for biofuel production. According to the proposed flow field design of ARID-HV algal raceway, experiments and numerical simulation have been conducted to understand the enhancement of flow mixing in the flow field of ARID-HV raceway by cutting slots on top of the dam near the dead zones. A new method was proposed to quantitatively evaluate the flow mixing by using the statistics of temporal and spatial distribution of the massless fluid particles (centered in each cell at the inlet surface) in the raceway collecting the data of path-lines of fluid particles from CFD results. It is hoped that this method can be applied to assist the algal raceway flow field design as well as other engineering applications. The third part introduces the details about the construction work of a high temperature molten salt test loop. Because of the limited operating temperature of conventional synthetic oils, in order to obtain higher energy conversion efficiency, higher operating temperature is always desirable in a CSP plant which leads to the requirement of new generation of HTF. Currently, a halide salt eutectic mixture (NaCl-KCl-ZnCl₂) as a potential HTF for future CSP applications has been proposed by a multi-institute research team, led by University of Arizona. The thermophysical properties of the halide eutectic salt have been measured. However, this new developed halide eutectic salt has not been tested in a circulating loop at a high operating temperature for the measurement of heat transfer coefficient. It is a significant effort to build such a test system due to extremely high operating temperature. As a consequence, in the third part of this dissertation, details about the design of the lab-scale test system and all the equipment items will be introduced. The investigations included in this dissertation for the heat transfer and flow in solar energy and bioenergy systems are of particular interest to the renewable energy engineering community. It is expected that the proposed methods can provide useful information for engineers and researchers.

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23

Guarnieri, Raniero Alberto. "Novel approaches to the design of domestic solar hot water systems." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16056/1/Raniero_Guarnieri_Thesis.pdf.

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Domestic solar hot water units, if properly designed, are capable of providing all hot water needs in an environmentally friendly and cost-effective way. Despite 50 years of development, commercial technology has not yet achieved substantial market penetration compared to mainstream electric and gas options. Therefore, alternate designs are warranted if they can offer similar or greater performance for a comparable cost to conventional units. This study proved that such alternatives are possible by designing and testing two novel solar hot water systems (SHWS). The first system used compound parabolic collector (CPC) panels to concentrate solar energy and produce steam. The steam moved from a rooftop downward into a heat exchange pipe within a ground level water tank, heating the water, condensing and falling into a receptacle. The operation was entirely passive, since the condensate was pulled up due to the partial vacuum that occurred after system cooling. Efficiencies of up to 40% were obtained. The second system used an air heater panel. Air was circulated in open and closed loop configuration (air recycling) by means of a fan/blower motor and was forced across a compact heat exchanger coupled to a water tank. This produced a natural thermosiphon flow heating the water. Air recycling mode provided higher system efficiencies: 34% vs. 27%. The concurrent development of an analytical model that reasonably predicted heat transfer dynamics of these systems allowed 1) performance optimisation for specific input/starting operating conditions and 2) virtual design improvements. The merit of this model lay in its acceptable accuracy in spite of its simplicity. By optimising for operating conditions and parameter design, both systems are capable of providing over 30 MJ of useful domestic hot water on clear days, which equates roughly to an increase of 35°C in a 200 L water tank. This will satisfy, on average, daily hot water requirements for a 4-person household, particularly in low-latitude regions (eg. Queensland). Preliminary costing for these systems puts them on par with conventional units, with the passive, remotely coupled, low maintenance, CPC SHWS comparable to higher end models. The air heater SHWS, by contrast, was much more economical and easier to build and handle, but at the trade-off cost of 1) the need for an active system, 2) increased maintenance and running costs and 3) the requirement for a temperature control mechanism that would protect the panel body by dumping hot air trapped inside if stagnation were to occur.

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24

Guarnieri, Raniero Alberto. "Novel Approaches to the Design of Domestic Solar Hot Water Systems." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16056/.

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Domestic solar hot water units, if properly designed, are capable of providing all hot water needs in an environmentally friendly and cost-effective way. Despite 50 years of development, commercial technology has not yet achieved substantial market penetration compared to mainstream electric and gas options. Therefore, alternate designs are warranted if they can offer similar or greater performance for a comparable cost to conventional units. This study proved that such alternatives are possible by designing and testing two novel solar hot water systems (SHWS). The first system used compound parabolic collector (CPC) panels to concentrate solar energy and produce steam. The steam moved from a rooftop downward into a heat exchange pipe within a ground level water tank, heating the water, condensing and falling into a receptacle. The operation was entirely passive, since the condensate was pulled up due to the partial vacuum that occurred after system cooling. Efficiencies of up to 40% were obtained. The second system used an air heater panel. Air was circulated in open and closed loop configuration (air recycling) by means of a fan/blower motor and was forced across a compact heat exchanger coupled to a water tank. This produced a natural thermosiphon flow heating the water. Air recycling mode provided higher system efficiencies: 34% vs. 27%. The concurrent development of an analytical model that reasonably predicted heat transfer dynamics of these systems allowed 1) performance optimisation for specific input/starting operating conditions and 2) virtual design improvements. The merit of this model lay in its acceptable accuracy in spite of its simplicity. By optimising for operating conditions and parameter design, both systems are capable of providing over 30 MJ of useful domestic hot water on clear days, which equates roughly to an increase of 35°C in a 200 L water tank. This will satisfy, on average, daily hot water requirements for a 4-person household, particularly in low-latitude regions (eg. Queensland). Preliminary costing for these systems puts them on par with conventional units, with the passive, remotely coupled, low maintenance, CPC SHWS comparable to higher end models. The air heater SHWS, by contrast, was much more economical and easier to build and handle, but at the trade-off cost of 1) the need for an active system, 2) increased maintenance and running costs and 3) the requirement for a temperature control mechanism that would protect the panel body by dumping hot air trapped inside if stagnation were to occur.

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25

Yandt, Mark. "Characterization Techniques and Optimization Principles for Multi-Junction Solar Cells and Maximum Long Term Performance of CPV Systems." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35870.

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Two related bodies of work are presented, both of which aim to further the rapid development of next generation concentrating photovoltaic systems using high efficiency multi junction solar cells. They are complementary since the characterization of commercial devices and the systematic application of design principles for future designs must progress in parallel in order to accelerate iterative improvements. First addressed, is the field characterization of state of the art concentrating photovoltaic systems. Performance modeling and root cause analysis of deviations from the modeling results are critical for bringing reliable high value products to the market. Two complementary tools are presented that facilitate acceleration of the development cycle. The “Dynamic real-time I V Curve Measurement System…” provides a live picture of the current-voltage characteristics of a CPV module. This provides the user with an intuitive understanding of how module performance responds under perturbation. The “Shutter technique for noninvasive individual cell characterization in sealed concentrating photovoltaic modules,” allows the user to probe individual cell characteristics within a sealed module. This facilitates non-invasive characterization of modules that are in situ. Together, these tools were used to diagnose the wide spread failure of epoxy connections between the carrier and the emitter of bypass diodes installed in sealed commercial modules. Next, the optimization principals that are used to choose energy yield maximizing bandgap combinations for multi-junction solar cells are investigated. It is well understood that, due to differences in the solar resource in different geographical locations, this is fundamentally a local optimization problem. However, until now, a robust methodology for determining the influences of geography and atmospheric content on the ideal design point has not been developed. This analysis is presented and the influence of changing environment on the representative spectra that are used to optimize bandgap combinations is demonstrated. Calculations are confirmed with ground measurements in Ottawa, Canada and the global trends are refined for this particular location. Further, as cell designers begin to take advantage of more flexible manufacturing processes, it is critical to know if and how optimization criteria must change for solar cells with more junctions. This analysis is expanded to account for the differences between cells with up to 8 subcell bandgaps. A number of software tools were also developed for the Sunlab during this work. A multi-junction solar cell model calibration tool was developed to determine the parameters that describe each subcell. The tool fits a two diode model to temperature dependent measurements of each subcell and provides the fitting parameters so that the performance of multi-junction solar cells composed of those subcells can be modeled for real world conditions before they are put on-sun. A multi-junction bandgap optimization tool was developed to more quickly and robustly determine the ideal bandgap combinations for a set of input spectra. The optimization process outputs the current results during iteration so that they may be visualized. Finally, software tools that compute annual energy yield for input multi-junction cell parameters were developed. Both a brute force tool that computes energy harvested at each time step, and an accelerated tool that first bins time steps into discrete bins were developed. These tools will continue to be used by members of the Sunlab.

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26

Simsek, Mehmet [Verfasser], Frank [Gutachter] Nürnberger, and Jochen [Gutachter] Kaiser. "Reaktivitätsmuster des Orexin-Systems im Hypothalamus der C57BL- und der C3H-Maus unter Wach-Bedingung, während des Schlafes und nach Schlafentzug – Interaktion mit dem Melanin-concentrating hormone (MCH)-System / Mehmet Simsek ; Gutachter: Frank Nürnberger, Jochen Kaiser." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2018. http://d-nb.info/1164077449/34.

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27

Howard, Dustin F. "Modeling, simulation, and analysis of grid connected dish-stirling solar power plants." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34832.

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The percentage of renewable energy within the global electric power generation portfolio is expected to increase rapidly over the next few decades due to increasing concerns about climate change, fossil fuel costs, and energy security. Solar thermal energy, also known as concentrating solar power (CSP), is emerging as an important solution to new demands for clean, renewable electricity generation. Dish-Stirling (DS) technology, a form of CSP, is a relatively new player in the renewable energy market, although research in the technology has been ongoing now for nearly thirty years. The first large plant utilizing DS technology, rated at 1.5 MW, came online in January 2010 in Peoria, AZ, and plants rated for several hundred MW are in the planning stages. Increasing capacity of this technology within the utility grid requires extensive dynamic simulation studies to ensure that the power system maintains its safety and reliability in spite of the technological challenges that DS technology presents, particularly related to the intermittency of the energy source and its use of a non-conventional asynchronous generator. The research presented in this thesis attempts to fill in the gaps between the well established research on Stirling engines in the world of thermodynamics and the use of DS systems in electric power system applications, a topic which has received scant attention in publications since the emergence of this technology. DS technology uses a paraboloidal shaped dish of mirrors to concentrate sunlight to a single point. The high temperatures achieved at the focal point of the mirrors is used as a heat source for the Stirling engine, which is a closed-cycle, external heat engine. Invented by the Scottish clergyman Robert Stirling in 1816, the Stirling engine is capable of high efficiency and releases no emissions, making it highly compatible with concentrated solar energy. The Stirling engine turns a squirrel-cage induction generator, where electricity is delivered through underground cables from thousands of independent, autonomous 10-25 kW rated DS units in a large solar farm. A dynamic model of the DS system is presented in this thesis, including models of the Stirling engine working gas and mechanical dynamics. Custom FORTRAN code is written to model the Stirling engine dynamics within PSCAD/EMTDC. The Stirling engine and various other components of the DS system are incorporated into an electrical network, including first a single-machine, infinite bus network, and then a larger 12-bus network including conventional generators, loads, and transmission lines. An analysis of the DS control systems is presented, and simulation results are provided to demonstrate the system's steady state and dynamic behavior within these electric power networks. Potential grid interconnection requirements are discussed, including issues with power factor correction and low voltage ride-through, and simulation results are provided to illustrate the dish-Stirling system's capability for meeting such requirements.

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28

Nahhas, Tamar. "Materials and thermal storage systems by sensible heat for thermodynamic electro-solar plants." Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0027.

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L'énergie solaire est connue pour sa nature intermittente par rapport aux ressources d’énergie fossile. Cette observation souligne la nécessité d'utilisation d’un système de stockage d'énergie thermique. Le système de stockage thermocline est considéré comme un système de stockage rentable. La présente thèse vise à étudier le potentiel des roches basaltiques et siliceuses comme des candidates matériaux de stockage pour les centrales solaires concentrées. Les études expérimentales des propriétés thermo-physiques et thermomécaniques de ces roches à des températures allant jusqu'à 1000°C montrent que ces roches offrent de bonnes propriétés thermiques par rapport aux matériaux classiques de stockage. L'analyse du système de stockage thermocline sur un lit de roches à air direct est réalisée par une approche numérique. En outre, cette recherche vise également à évaluer l’impact environnementale de ce type de système de stockage en effectuant une analyse comparative de son cycle de vie. Enfin, une étude complémentaire réalisée dans le but de produire une carte d'indice de pertinence a permis d’identifier les zones les plus appropriées pour la construction des centrales solaires en Egypte. L'originalité de cette approche alternative pour le stockage d'énergie thermique est qu’elle combine la performance et la disponibilité des matériaux de stockage tout en réduisant leurs impacts environnementaux et financiers Compare to fossil fuel energy resources, solar energy is known for its intermittent nature. This observation highlights the need for the use of a thermal energy storage system. The thermocline storage system is considered as a cost-effective storage system. This thesis aims to study the potential of basalt and silex rocks as candidate storage materials for concentrated solar power plants. Experimental studies of the thermo-physical and thermo-mechanical properties of these rocks at temperatures up to 1000°C show that these rocks offer good thermal properties compared with conventional storage materials. The analysis of the thermocline storage system of air rock-packed bed is carried out using a numerical approach. This research also aims to assess the environmental impact of this type of storage system by conducting a comparative analysis of its life cycle. Finally, a complementary study carried out with the aim of producing a relevance index map made it possible to identify the most suitable areas for the construction of solar power plants in Egypt. The originality of this alternative approach for thermal energy storage is that it combines the performance and availability of storage materials while reducing their environmental and financial impacts

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Hallberg, Maria, and Elin Hallme. "Introducing a central receiver system for industrial high-temperature process heat applications : A techno-economic case study of a large-scale CST plant system in a South African manganese sinter plant." Thesis, KTH, Kraft- och värmeteknologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-249067.

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The objective of this thesis was to investigate the potential for introducing a concentrating solar thermal (CST) central receiver plant system based on flexible heliostats - HelioPods - to provide high-temperature process heat in industrial applications. A CST plant system was designed in MATLAB, optically simulated for three design days in the ray-tracing software Tonatiuh and further analyzed in MATLAB by interpolating the results for each hour of the year. A case study was made on introducing a CST plant system based on HelioPods in a South African manganese sinter plant. The study included an investigation of the profitability of up- and downsizing the heliostat field annually with fluctuating heat demand. A circular heliostat field was modelled for the chosen location. The final field had a radius of 53 meters with the receiver located 60% from the field centre. The storage size was 16 demand hours and 17 plants were required. The results showed that 88% of the annual heat demand could be covered by solar heat in the design year. The marketing approach used for the following years was that the heat demand covered by solar heat should never be below the share at the first year, despite the predicted fluctuations in demand. Thus, a minimum solar share of 88% was used as a strategy for annual up- and downsizing of the fields throughout the investigated period of 25 years. That resulted in a field radius differing between 52 and 55 meters. The payback period of the final system was 4.35 years, the NPV was 54.33 MUSD over a period of 25 years and the LCOH was 35.39 USD/MWht. However, it was found that the profitability of the system was sensitive to the different scenarios for predicted future diesel prices, this since the pricing of the solar heat was set to 90% of the diesel price. The results in this thesis show that a CST plant system based on HelioPods is a suitable solution to supply high-temperature process heat to industrial applications. It also shows that the HelioPods can unlock potential for flexibility with changing production patterns in the industry of implementation. The results from the study can be used also for other industries with similar temperature range and heat demand. Thus, it could be argued that the implementation of a HelioPod based CST plant system also can be suitable for other industries located in high-DNI areas with dependency on conventional fuels and steady production throughout the whole day. Syftet med denna uppsats var att undersöka potentialen för implementering av koncentrerad termisk solvärme (CST) från ett soltorn med ett heliostatfält baserat på flexibla heliostater - HelioPods – för att generera högtempererad processvärme för industriell tillämpning. Ett CST-system designades i MATLAB, simulerades för tre designdagar i det optiska ray-tracingprogrammet Tonatiuh och analyserades sedan åter i MATLAB genom att interpolera de genererade resultaten för årets alla timmar. En fallstudie av ett CST-system baserat på HelioPods i ett sydafrikanskt sinterverk för mangan genomfördes därefter. Studien innehöll en undersökning av lönsamheten av årlig ökning och minskning av heliostatfältet vid fluktuerande värmebehov. Ett cirkulärt heliostatfält modellerades för den valda platsen. Det slutgiltiga fältet hade en radie om 53 meter med mottagaren placerad 60% från fältets mittpunkt. Storleken på lagringsfaciliteten var 16 timmar av full tillförsel och antalet verk uppgick till 17. Resultaten visade att 88% av det årliga värmebehovet kunde förses med solvärme under designåret. Marknadsstrategin för de resterande åren var att den procentuella andelen solvärme aldrig skulle vara lägre än under designåret, oberoende av fluktuationer i värmebehovet på grund av ändrad produktion. Således sattes 88% solvärme som ett minimikrav och utgjorde strategin för den årliga ökningen och minskningen av fältet för den undersökta perioden av 25 år. Det resulterade i en fältradie mellan 52 och 55 meter. Återbetalningstiden för det slutgiltiga fältet var 4.35 år, nuvärdesberäkningen av det framtida kassaflödet var 54.22 miljoner USD över en 25-årsperiod och produktionskostnaden för värme (LCOH) var 35.39 USD/MWht. Dock var systemets lönsamhet känslig för de olika prognoser av framtida dieselpriser som undersöktes, detta eftersom priset för solvärme sattes till 90% av dieselpriset. Resultaten i denna uppsats visar att ett CST-system baserat på HelioPods är en lämplig lösning för att generera högtempererad processvärme för industriell tillämpning. De visar även att HelioPods kan öka potentialen för flexibilitet vid förändringar i produktionsmönstret i vederbörande industri. Resultaten kan även användas i andra industrier med likartade temperaturer och värmebehov. Hävdas kan således att implementation av ett CST-system kan vara lämpligt även för andra industrier belägna i områden med högt DNI som är beroende på konventionella energikällor och har jämn produktion dygnet runt.

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Henderson, Courtney Francis Keith. "The Chemical and Biological Mechanisms of Nutrient Removal from Stormwater in Bioretention Systems." Thesis, Griffith University, 2009. http://hdl.handle.net/10072/366977.

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High concentrations of dissolved nutrients in stormwater have been identified as contributing to eutrophication of receiving waterways near urban areas. To reduce dissolved nutrient concentrations in stormwater a range of devices such as wetlands and bioretention systems are used. Bioretention systems are increasingly employed for their supposedly high nutrient removal capacity, however very little is known about their treatment efficiency or the chemical and biological mechanisms controlling their function. This research aimed firstly to test and compare the efficiency of different bioretention system designs for the removal of dissolved nutrients from stormwater, and secondly to investigate the chemical and biological mechanisms responsible for the nutrient removal (sorption, microbial uptake, and plant uptake). Bioretention mesocosms were built in plastic containers (1 m x 0.5 m x 0.5 m). Three different media treatments were built, representing those most commonly used: gravel, fine sand and loamy-sand. To assess the nutrient removal capacity of plants, vegetated and unvegetated examples of each media type were made. The mesocosms were regularly irrigated with tap water for six months, and then regularly irrigated with synthetic stormwater for a further six months to ensure that the treatment performance assessed would represent fully established systems. The synthetic stormwater solution was based on field measurements of stormwater, and was made using a combination of inorganic chemicals and organic fertilisers. By incorporating organic carbon and major cations (Ca, Mg, Na, K), the measured treatment performance of the biofilters would be more realistic than previous studies that did not corporate these compounds. Some mesocosms were watered only with tap water so that the effect of frequent fertilisation (enrichment) could be compared. It was expected that vegetated media would enhance nutrient removal directly through plant uptake, and indirectly by stimulating microbial productivity and microbial uptake in the rhizosphere. Nutrient removal was evaluated by comparing the influent to the effluent. Detention times of 24 and 72 hours were compared to test if longer contact periods resulted in greater nutrient removal. The mesocosms were also flushed with tap water (no nutrients) to determine the proportion of entrained nutrients that might subsequently leach from the media. Vegetated bioretention mesocosms were much more efficient than unvegetated systems at removing total nitrogen (63 – 77 % removal compared to -12 – 25 %) and total phosphorus (85 – 94 % removal compared to 31 – 90 %). The vegetation effect did not improve dissolved organic carbon removal but there was a difference between soil types, with smaller particle size media removing more organic carbon. Enriched mesocosms removed similar quantities of nutrients to non-enriched mesocosms. Extending the detention time from 24 hours to 72 hours slightly increased the removal of total nitrogen from the vegetated mesocosms, but reduced total nitrogen removal from unvegetated mesocosms. When flushed with tap water, inorganic and organic forms of nitrogen and phosphorus leached from the unvegetated mesocosms, but were mostly retained within the vegetated mesocosms... Thesis (PhD Doctorate) Doctor of Philosophy (PhD) School of Engineering Science, Environment, Engineering and Technology Full Text

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31

Galagan, A. A. "High concentration photovoltaic thermal system." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/33625.

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Researchers from IBM have created a very impressive and affordable new photovoltaic system that is capable of concentrating solar radiation up to 2000 times. The system is also capable of converting 80% of incoming solar radiation into useful energy. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33625

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32

Goldman, Dan. "The Architecture of templers in their colonies in Eretz-Israel, 1868-1948, and their settlements in the United States, 1860-1925 : with a concentration on: architectural history of templers' colonies in Israel and the U.S. /." [S.l.] : [s.n.], 2003. http://lib.haifa.ac.il/systems/elect_data/etexts/1102075.pdf.

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Mahfuz, Mohammad Upal. "Fundamentals of Concentration-encoded Molecular Communication." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31767.

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Molecular communication (MC) is a new bio-inspired communication paradigm towards realizing the communication and networking at the nanoscale to microscale dimensions among a vast number of engineered natural and/or artificial nanomachines communicating with each other to form a nanonetwork. In this thesis, we investigate a concentration-encoded molecular communication (CEMC) system where the transmitting nanomachine (TN) and the receiving nanomachine (RN) communicate with a single type of information molecules by modulating the transmission rate of information molecules at the TN. The information molecules undergo ideal (i.e. free) diffusion in three dimensions and become available to the RN that observes the concentration of the received molecules at its receptors and thus decodes the message. Our research shows that it is possible to realize complex modulation methods, combat the intersymbol interference (ISI), determine the effective communication ranges based on available signal concentration, develop signal detection schemes, and apply simple channel codes in a CEMC system. It has been found that the performance of the CEMC system is influenced by communication ranges, transmission data rates, ISI, and detection schemes. It is possible to sense the concentration signal intensity and develop optimum receiver structures that can detect the transmitted symbols at the RN. It is also possible to develop optimum signal detection schemes based on the interactions between the information molecules and the receptors using stochastic chemical kinetics (SCK) of the reaction events. Applying simple channel codes at the TN shows that it is possible to increase effective communication range in the CEMC system, however, this increases the complexity of the RN in implementing the detection circuitry. Finally, potential applications of CEMC would be in materializing CEMC-based molecular nanonetworks for emerging areas, e.g. in cancer detection and treatment, targeted drug delivery, and environmental protection and pollution control.

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34

Muron, Aaron C. D. "Field Installation of a Fully Instrumented Prototype Solar Concentrator System: Thermal and Photovoltaic Analysis." Thesis, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26245.

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Concentrator photovoltaics (CPV) is one of the most promising renewable technologies owing to its high efficiency, scalability, low operating expense, and small environmental impact. However, there is much research and advancements to be made before CPV is established as a cost competitive energy technology. To this end, Morgan Solar has developed the Sun Simba, an innovative light weight and low cost CPV module. Under the “Advancing Photonics for Economical Concentration Systems” (APECS) project, outdoor CPV test and measurement systems were designed and constructed at the University of Ottawa and at Little Rock, CA. The performance and reliability of development stage Sun Simba modules installed at the University of Ottawa is assessed. The Little Rock test system was constructed for purposes of future comparison and assessment. To properly assess the performance, instrumentation and data acquisition systems to measure meterological parameters and the associated electrical performance are described and the long-term performance of Sun Simba modules installed at the University of Ottawa is summarized. A finite element model of a cell-on-carrier assembly was constructed to explore the parameter space of the carrier and suggest improvements in carrier design. The effect of carrier geometry, material choices, and convective boundary conditions and their influence on the cell efficiency is determined. The modelling results connected to the measured data is used to estimate the heat sinking capability of the second generation Sun Simba modules.

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35

Melton, Patricia Mary. "The characterisation of liquid atomisation systems." Thesis, University of Essex, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235599.

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36

Lin, Tao. "Concentration of bacterial pathogens using microfluidic dielectrophoresis systems." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/23815.

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Over the course of human history, people have been always troubled by unpredictable outbreaks of pathogenic bacteria. A rapid, specific and durable diagnostic sensor for detecting pathogens in a timely fashion is essential for identifying unknown infectious diseases and reacting by offering proper patient management and public health involvement without delay. Development of a microfluidic system incorporating interdigitated electrodes for characterizing concentration, purification and differentiation of pathogenic bacteria is presented. Polystyrene microspheres, Salmonella typhimurium, Campylobacter jejuni, Escherichia coli and Mycobacterium smegmatis are trapped by the positive dielectrophoretic force produced by the microelectrodes deposited and arrayed on a glass substrate covered with a PDMS microchannel. Diluted buffer used for producing positive dielectrophoresis for capturing cells is selected after evaluating the viability of the cells suspended in different buffers. Trapping efficiencies of Escherichia coli and Mycobacterium smegmatis are acquired by comparing input concentration and output concentration from plating results. Effective conductivities of both Escherichia coli and Mycobacterium smegmatis are calculated by obtaining optical density measurements corresponding to certain buffers with a range of different conductivity values used for trapping. Separation of a mixture with Escherichia coli and Mycobacterium smegmatis is achieved through the microconcentrator, although the results conflict with the calculated cellular conductivity values. The microfluidic DEP concentrator is shown to be an effective tool for studying and separating bacterial populations, and the results clearly indicate exciting directions for future work.

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Calixto, João Paulo Duarte. "Concentration of tumor biomarkers using aqueous biphasic systems." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15353.

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Mestrado em Bioquímica - Bioquímica Clínica According to the World Health Organization, around 8.2 million people die each year with cancer. Most patients do not perform routine diagnoses and the symptoms, in most situations, occur when the patient is already at an advanced stage of the disease, consequently resulting in a high cancer mortality. Currently, prostate cancer is the second leading cause of death among males worldwide. In Portugal, this is the most diagnosed type of cancer and the third that causes more deaths. Taking into account that there is no cure for advanced stages of prostate cancer, the main strategy comprises an early diagnosis to increase the successful rate of the treatment. The prostate specific antigen (PSA) is an important biomarker of prostate cancer that can be detected in biological fluids, including blood, urine and semen. However, the commercial kits available are addressed for blood samples and the commonly used analytical methods for their detection and quantification requires specialized staff, specific equipment and extensive sample processing, resulting in an expensive process. Thus, the aim of this MSc thesis consisted on the development of a simple, efficient and less expensive method for the extraction and concentration of PSA from urine samples using aqueous biphasic systems (ABS) composed of ionic liquids. Initially, the phase diagrams of a set of aqueous biphasic systems composed of an organic salt and ionic liquids were determined. Then, their ability to extract PSA was ascertained. The obtained results reveal that in the tested systems the prostate specific antigen is completely extracted to the ionic-liquid-rich phase in a single step. Subsequently, the applicability of the investigated ABS for the concentration of PSA was addressed, either from aqueous solutions or urine samples. The low concentration of this biomarker in urine (clinically significant below 150 ng/mL) usually hinders its detection by conventional analytical techniques. The obtained results showed that it is possible to extract and concentrate PSA, up to 250 times in a single-step, so that it can be identified and quantified using less expensive techniques. De acordo com dados disponibilizados pela Organização Mundial de Saúde, cerca de 8,2 milhões de pessoas morrem anualmente com cancro. A elevada taxa de mortalidade associada ao cancro resulta da maioria dos pacientes não efetuar exames de rotina e porque a manifestação dos sintomas, na maioria dos casos, acontece quando o paciente já se encontra numa fase avançada da doença. Atualmente, o cancro da próstata representa a segunda maior causa de morte entre indivíduos do sexo masculino em todo o mundo. Tendo em conta que não existe cura para casos avançados de cancro da próstata, a estratégia passa por um diagnóstico precoce que permita aumentar a taxa de sucesso dos tratamentos. O antigénio prostático específico (PSA) é um biomarcador importante do cancro da próstata que pode ser detetado em fluidos biológicos, nomeadamente sangue, urina e sémen. No entanto, os kits comerciais disponíveis utilizam amostras de sangue e os métodos analíticos normalmente utilizados na sua deteção e quantificação requerem pessoal especializado, equipamento específico e um processamento extensivo das amostras, resultando em processos com um elevado custo associado. Assim, o objetivo deste mestrado passou por desenvolver um método simples, eficiente e menos dispendioso para a extração e concentração de PSA a partir de amostras de urina utilizando sistemas aquosos bifásicos (SAB) constituídos por líquidos iónicos. Numa fase inicial, determinaram-se os diagramas de fases de um conjunto de sistemas aquosos bifásicos constituídos por um sal orgânico e por líquidos iónicos. Em seguida, avaliou-se a capacidade dos mesmos para a extração do PSA. Os resultados obtidos demonstram que, nos sistemas em estudo, o antigénio prostático específico é totalmente extraído para a fase rica em líquido iónico num único passo. Por fim, averiguou-se a aplicabilidade dos SAB estudados para a concentração do PSA a partir de soluções aquosas e de urina. A baixa concentração deste biomarcador na urina (clinicamente significativo abaixo de 150 ng/mL) dificulta a sua deteção através de técnicas analíticas convencionais. Os resultados obtidos demonstraram que é possível extrair e concentrar PSA até 250 vezes, numa única etapa, sendo este detetável através de técnicas menos dispendiosas.

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38

Jie, Shi Chang. "Chinese New Telemetry Onboard System." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/611666.

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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California This paper at first gives a brief historical review of Chinese development of telemetering onboard system and then make a brief introduction of new onboard system from several respects.

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39

McClure-Sharp, Jilliane Mary, and mikewood@deakin edu au. "Regulation of corticotropin-releasing factor concentration and overflow in the rat central nervous system." Deakin University. School of Biological and Chemical Sciences, 1998. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20060802.143911.

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Corticotropin-releasing factor (CRF) is the primary hormone of the hypothalamo-pituitary adrenal axis (HPA-axis). In addition to its endocrine function, it has been proposed that CRF acts as a neurotransmitter. The widespread distribution of CRF immunoreactivity and CRF receptors in the rat central nervous system (CNS) supports this theory. Immunohistochemical studies have demonstrated high levels of CRF immunoreactivity the rat hypothalamus, a brain region involved in the regulation and integration of a variety of endocrine and autonomic homeostatic mechanisms. CRF has been shown to be involved in a number of these activities such as blood pressure control, food and water intake, behaviour and emotional integration. Many of these activities demonstrate progressive dysfunction as ageing proceeds. The aim of this thesis was to investigate the regulation of CRF in the rat CNS, particularly over the period of maturation and ageing. Tissue extraction and peptide radioimmunoassay (RIA) techniques were developed in order to measure regional CRF concentrations as a function of age in the rat CNS. Seven brain regions were examined including the hypothalamus, pituitary, medulla oblongata, pons, cerebral cortex, cerebellum and midbrain. Three age ranges were investigated: 3 4 weeks, 4 5 months and 14 18 months, representing young, mature and old age groups. Data for the tissues of individual rats from each age group were analysed using one-way analysis of variance (ANOVA) with post-hoc Scheffé tests (SPSS Release 6 for Windows, 1989 1993). CRF were detected in measurable quantities in all brain regions examined. Different age-related patterns of change were observed in each brain region. CRF concentrations (ng/g tissue) were highest in the pituitaries of young rats and were significantly reduced over the period of maturation (P< 0.05). However, the high CRF concentration of the young rat pituitary was likely to be a factor of the smaller tissue mass. Although the absolute CRF content (ng/tissue) of this tissue appeared to decline with maturation and ageing, the reduction was not significant (P>0.05). Therefore the pituitary of the young rat was relatively enriched with CRF per gram tissue. The highest CRF concentration in mature and aged rats was measured in the hypothalamus, in accordance with previous immunohistochemical studies. Hypothalamic CRF concentrations (ng/g tissue) demonstrated no significant alterations with maturation and ageing. The absolute CRF content (ng/tissue) of the hypothalamus was significantly less in the young rat compared to mature and aged animals, however this was accompanied by a smaller tissue mass (P<0.05). The CRF concentrations (ng/g tissue) of the rat cerebral cortex and medulla oblongata demonstrated significant reduction with advancing age (P<0.05), however in both cases this appeared to be due to significant increases in mean tissue mass. The absolute CRF content of these tissues (ng/tissue) were not significantly different over the period of maturation and ageing (P>0.05). CRF concentration (ng/g tissue) and absolute content (ng/tissue) of the pons demonstrated a trend to increase with advanced age in the rat, however this was not significant in both cases (P>0.05). Of interest were the significant increases observed in the CRF concentrations of the cerebellum and midbrain (ng/g tissue with advanced ageing (P<0.05). Significant increases were also observed in the mean tissue mass and absolute CRF content (ng/tissue) of these regions in aged rats (P<0.05). These findings perhaps indicate increased CRF synthesis and or decreased CRF turnover in these tissues with advancing age. The second stage of these studies examined age-related alterations in basal and potassium-stimulated hypothalamic CRF and overflow over the period of maturation and ageing in the rat, and required the preliminary development of an in vitro tissue superfusion system. The concomitant release of the co-modulatory compound, neuropeptide Y (NPY) was also measured. NPY has been shown to positively regulate CRF release and gene expression in the hypothalamus. In addition, NPY has been demonstrated to be involved in a number of hypothalamic activities, including blood pressure control and food intake regulation. Hypothalamic superfusion data were analysed using one factor repeated measures ANOVA (SPSS Release 6 for Windows, 1989-1993) followed by least significant difference tests ( Snedecor and Cochran, 1967) to enable both time and age comparisons. Basal hypothalamic CRF overflow was unaltered with maturation and ageing in the rat. Potassium stimulation (56 mM) elicted a significant 2 3 fold increase in hypothalamic CRF overflow across age groups (P<0.05). Stimulated hypothalamic CRF overflow was significantly greater in the young rat compared to the mature and aged animals (P<0.05). The enhanced response to depolarizing stimulus was observed at an age when the absolute CRF content of the hypothalamus was significantly less that of other age groups. It is possible that the enhanced responsiveness of the young rat may be of survival advantage in life threatening situations. Basal hypothalamic NPY overflow was much less than that of CRF, and potassium stimulation resulted in a very different age-related profile. The hypothalamic NPY response to depolarization was significantly reduced in the young rat and declined significantly with advanced ageing (P<0.05). The contrasting profiles of stimulated CRF and NPY overflow may indicate the activity of alternative regulatory factors present in the hypothalamus, whose activity may also be affected in an age-related manner. The final stage of these studies examined the nature of NPY modulation of hypothalamic CRF overflow in the mature rat. The facilitatory effect of NPY on hypothalamic CRF overflow was confirmed. The application of NPY (0.1 µM) significantly increased CRF overflow approximately 4 fold of basal (P<0.05). In addition, the role of the NPY-Y1 receptor was investigated by the prior application of Y1 receptor antagonists, GW1229 (0.05 µM). At this concentration GW1229 significantly reduced hypothalamic CRF overflow induced by perfusion with NPY (0.1 µm), P<0.05. It was concluded the Y1 receptor does have a role in the regulation of hypothalamic CRF overflow by NPY.

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40

Klugman, Piers. "Electrical design and commissioning of a solar trough concentrating system." Thesis, Klugman, Piers (2015) Electrical design and commissioning of a solar trough concentrating system. Other thesis, Murdoch University, 2015. https://researchrepository.murdoch.edu.au/id/eprint/27599/.

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This thesis outlines the electrical design, re-commissioning and testing of a photovoltaic (PV) solar trough concentrating system (STCS) at Murdoch University’s South St campus. In order to become familiar with the system a literature review and system audit were undertaken. From this it was clear that a substantial amount of work was required to be undertaken to able to re-commission the system and achieve grid connection. Approval for the grid connection was then sought and granted from the University’s facility management. As part of the approval process the electrical design and specifications were developed. The inverters and components required to undertake the rewiring of the array were then purchased. In addition to this, the dual axis tracking system was re-commissioned and tested, and where necessary repairs were made to improve its performance and reliability. Work was also carried out on the PV receivers to improve their electrical cabling insulation. Once this was achieved the entire DC side of the array was re-wired and grid connected through two singles phase string inverters. Commissioning, testing and collection of data from the array was then carried out, the details of which are discussed in the results section of this report. This project was ultimately successful and the PV STCS is now exporting electricity to the grid. The maximum power output of the system achieved so far is roughly 3kW, but once the system operation has been optimised, including thoroughly cleaning the parabolic trough mirrors, the system performance is expected to increase to at least 5kW in the future. It should also be noted that a number of figures and tables have been removed, as noted in Appendix P, as it was not possible to obtain copyright permission to reproduce them in this Thesis. The headings with references have been left in place to enable readers to find the images themselves if additional illustration of important concepts is required.

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Feng, Zhenzhou. "Design, build and testing of a concentrating solar dish system." Thesis, Feng, Zhenzhou (2017) Design, build and testing of a concentrating solar dish system. Honours thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/40399/.

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This study describes the retrofitting of an old satellite dish as a concentrating solar dish system and investigates the factors that influence its performance concerning power generation. The satellite dish retrofit is viable for future development. The scheme of the project is divided into modelling, simulation, and optimisation. Modelling and simulation for the retrofitted satellite dish have been carried out by using System Advisor Model (SAM) and Franco’s program. According to the simulation results generated by SAM, the target dish can collect a maximum power of 2.987 MWh in January and a minimum power of 0.967 MWh in June. In this thesis, the effects on the system performance of several factors are studied, with factors including solar radiation resources, size of the dish, reflector material, focal point diameter, and cavity receiver thermal losses. Additionally, the theoretical design and analysis for a beta-type Stirling engine that integrates the retrofitted dish are provided as well. The performance of the engine can be enhanced by adopting the appropriate number of heater and cooler tubes to reduce the pumping losses in the regenerator and using more effective fluid. According to the simulation results that were generated by Franco’s program, the optimised peak power of the Stirling engine reaches almost 2.7kW and operates with a thermal efficiency of 43% at an engine speed of 64 Hz. A generator can be connected to keep the Stirling engine running at a constant speed once it reaches its maximum power. The retrofitted system can be used to power a water pump for irrigation purpose.

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Weatherwax, Trent. "Integrated mining and preconcentration systems for nickel sulfide ores." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/238.

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As part of a strategic research initiative at UBC to design and evaluate integrated underground mining and mineral processing systems, work has been done to determine how to utilize the coarse rejects of pre-concentration in the underground environment. An amenability study for nine orebodies from four of Xstrata Nickel’s Ontario operations evaluated both processing and waste disposal methods. Metallurgically the orebodies showed amenability to dense media separation and conductivity sorting. The dense media results showed high mass rejections and high metal recoveries for all nine orebodies. Conductivity sorter results were not as consistent, but still showed good results. Dense media rejects were examined to determine the applicability of their use in rockfills and composite minefills. The geotechnical properties indicated that the rejects would provide a competent material for minefills. The mix designs were examined for both strength and rheological properties and showed that fills utilizing rejects were comparable to fills currently used by industry. Composite fills containing rejects had significantly lower void ratios, decreasing cement requirements for a given strength requirement. Conceptual designs for pre-concentration systems based on the metallurgical, reject characterization, and mix design were developed for each of the four mines in the study. The designs took into consideration the current mining plans.

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Conte, Jeffrey E. "Analysis of a Fresnel concentrating spectral divider for a photovoltaic system." Virtual Press, 1987. http://liblink.bsu.edu/uhtbin/catkey/494976.

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To improve photovoltaic system efficiencies, concentrating spectral dividers are used to separate solar light, and to focus each spectral portion onto photovoltaic cells of matching spectral response. In this investigation, an optical analysis is developed to study the feasibility for use of a Fresnel half-lens as a concentrating spectral divider. To facilitate the analysis, an existing curved-base linear Fresnel lens ray-trace model has been modified and expanded. Solar limb-darkening has been incorporated into the theory by means of a digitized sun model. The lens model allows for variation of lens geometrical characteristics. Transmission losses due to Fresnel reflection and bulk absorption are taken into account. The distribution of the concentrated solar flux in the lens image plane is modeled such that spectral regions may be examined separately. Concentration ratio profiles are used to derive and evaluate a quantity of spectral separation.A computer program has been used to generate data, based on the theoretical model, for example lenses. The spectral separation, transmission and concentration properties for each example lens have been systematically studied with respect to lens geometry. The effects of solar limb-darkening are determined by comparison with the data from a model that assumes a uniform solar source. Results of the study are discussed in detail.Ball State UniversityMuncie, IN 47306

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Adkins, Deborah Anne. "Experimental and numerical modelling of mid-concentration photovoltaic concentrator systems." Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594866.

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For photovoltaics to achieve wide-scale implementation it is essential that their cost is reduced while maintaining or exceeding the present level of solar to electrical conversion performance. Concentrating solar energy onto a photovoltaic cell allows a reduction in the output electricity cost, if the cost of the concentrator is less than that of the displaced photovoltaic materials. Photovoltaic cell efficiency is shown to decrease with increasing temperature, causing the photovoltaic cells to exhibit both short-term (efficiency loss) and long term (irreversible damage) degradation due to excessive temperatures. Hence the analysis of thermal management is an important issue in photovoltaic power generating systems for both one-sun (lx) and concentrated applications. This thesis presents an experimental and numerical study of solar cell temperature in a midconcentration silicon photovoltaic concentrator (CPV), with a geometric concentration ratio of 42X. Experimental and computational fluid dynamic (CFO) modelling of heat transfer in six designs of CPV device is carried out. A detailed experimental study was designed and carried out in order to investigate the temperature and initial boundary conditions of the two initial CPV prototypes, with a without passive cooling arrangements, operating under standard test conditions (STC) in conjunction with the effect of environmental variables, namely the irradiance incident on the plane-of-array of the CPV module, the local wind speed and the ambient temperature on the operating temperatures of the CPV prototypes. The operating temperature is shown to depend strongly on the irradiance, less so on the wind speed and is found to be insensitive to short term fluctuations in ambient temperature. Temperature profiles of the CPV prototypes were measured experimentally with thermocouples placed both internally and externally along the enclosure and walls aJong the length of each CPV module. To investigate the performance of the CPV devices under a fixed set of repeatable environmental conditions, a solar simulator was designed and built to facilitate indoor testing at a range of illumination levels (0 to 1000W 1m2) and environmental conditions. Reviewing the results it was found that the spectrum and uniformity of irradiance source incident the plane of a single module (1 x 0.lm) is of great importance. The solar simulator was also found to artificially increase the module operating temperature, with greater temperatures recorded during indoor testing. Wind speed and direction measurements were taken in order to establish the module convective heat transfer coefficient (CHTC) which was determined to relatively insensitive to wind direction and to be a power law function of the mean wind speed. In the second phase of the work, three dimensional numerical studies of the photovoltaic concentrator prototypes were developed using ANSYS Fluent Computational Fluid Dynamic (CFD) software to solve the mass, momentum and energy transfer governing equations. The simulations provided thermal and dynamic maps of the fluid flow and the heat transfer between the cell and the passive cooling systems. The results show that a maximum of seven radial fins (CPV design 3) of 27mm height, 3.3mm thickness with a 4 degree taper can be effectively used to reduce the solar cell temperature, from 97.8"C with no cooling fins to 67.7"C with seven fins, measured at nominal operating cell temperature (NOCT) conditions. In addition. to validate the model. experimental measurements of temperature and flow characteristics are compared with experimental data. Numerical results of the CPV operating temperature are shown to have a strong correlation with experimental data with a maximum 0.3% deviation from experimental data for prototype one and a maximum 1.5% deviation from experimental data for prototype two. Simulation models are shown to be important design tools for predicting a photovoltaic concentrator's experimental and real world performance. Informed design decision making and optimisation is a significant goal of this work.

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Hatcher, M. G. "COMAS development for concentration probing of gas phase discharge systems." Thesis, Swansea University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637245.

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The work presented in this thesis describes the further development of the pump-probe laser spectroscopic technique known as Concentration-Modulated Absorption Spectroscopy (COMAS), concentrating on its use as an analytical tool for the investigation of various atomic systems. The systems analysed here include a direct current glow discharge with a lithium cathode, and a neon hollow cathode discharge lamp. The COMAS method necessitates the use of a Lock-In Amplifier (LIA) for signal derivation and output measurement. A substantial feature of the work presented here is concerned with the way in which COMAS signals are affected by phasing effects, and Chapter 2 concentrates on the relationship between COMAS signal generation and LIA measurement of that signal. Meaningful, quantitative analysis using COMAS generally requires the use of an accompanying absorbance measurement of the sample in question, and the development of COMAS has in fact been limited by the quality of such absorbance measurements. This problem is addressed in Chapter 3, which describes the investigation of two novel absorption techniques with a view to future use in conjunction with COMAS. With the theoretical and experimental basis to COMAS fully described in Chapter 4, the technique is subsequently used to probe the distribution of sputtered Li atoms in d.c. glow discharge for a variety of conditions. The results allow determination of the first experimentally derived values of thermalisation cross-sections in the gas phase, and provide valuable data for glow discharge modelling. In the final three chapters, the COMAS technique is significantly extended to incorporate analysis of dynamic 3-level systems. This development is approached theoretically in Chapter 6, and shows that certain extra parameters which affect COMAS signals require determination. The 3-level theoretical treatment is tested experimentally in Chapters 7 and 8 by investigation of a neon hollow cathode discharge, with the atomic neon electronic scheme providing an analogous 3-level system. The phase behaviour of the cw COMAS neon signals is briefly investigated in Chapter 8a.

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Chow, Simon Ka Ming. "Integration of High Efficiency Solar Cells on Carriers for Concentrating System Applications." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19932.

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High efficiency multi-junction (MJ) solar cells were packaged onto receiver systems. The efficiency change of concentrator cells under continuous high intensity illumination was done. Also, assessment of the receiver design on the overall performance of a Fresnel-type concentration system was investigated. We present on receiver designs including simulation results of their three-dimensional thermal operation and experimental results of tested packaged receivers to understand their efficiency in real world operation. Thermal measurements from solar simulators were obtained and used to calibrate the model in simulations. The best tested efficiency of 36.5% is obtained on a sample A receiver under 260 suns concentration by the XT-30 solar simulator and the corresponding cell operating temperature is ~30.5°C. The optimum copper thickness of a 5 cm by 5 cm simulated alumina receiver design was determined to be 6 mm and the corresponding cell temperature under 1000 suns concentration is ~36°C during operation.

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Lynn, Michael David. "The development and distribution of heavy mineral concentrations in alluvial systems." Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1005549.

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The objective of this review is to summarise the characteristics, significance and evolution of heavy minerals and their accumulations, and to identify the key controls on the development and distribution of heavy mineral concentrations in alluvial systems. These controls can be broadly classified as tectonic setting, geomorphic setting and grain-scale concentrating processes, each of which is discussed. Based on this review, exploration models are developed which are designed to indicate favourable localities for the accumulation of heavy minerals, and trends likely to be exhibited within these accumulations. The models are structured from the broadest scale of target selection, down to the local scale of sample site selection. The major conclusion of this work is that an understanding of process geomorphology is required to develop genetic models of placer development, including a detailed evaluation of climatic fluctuations throughout the Caenozoic. Palaeoplacers such as the Witwatersrand goldfield, are inferred to have formed under similar circumstances of tectonic setting as genetically comparable Caenozoic placers such as those of Otago, New Zealand. The means of preservation of such major basins is however poorly understood.

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Wu, Yuechen, and Raymond K. Kostuk. "Two-junction holographic spectrum-splitting microconcentrating photovoltaic system." SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 2017. http://hdl.handle.net/10150/623284.

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Spectrum-splitting is a multijunction photovoltaic technology that can effectively improve the conversion efficiency and reduce the cost of photovoltaic systems. Microscale PV design integrates a group of microconcentrating photovoltaic (CPV) systems into an array. It retains the benefits of CPV and obtains other benefits such as a compact form, improved heat rejection capacity, and more versatile PV cell interconnect configurations. We describe the design and performance of a two-junction holographic spectrum-splitting micro-CPV system that uses GaAs wide bandgap and silicon narrow bandgap PV cells. The performance of the system is simulated with a nonsequential raytracing model and compared to the performance of the highest efficiency PV cell used in the micro-CPVarray. The results show that the proposed system reaches the conversion efficiency of 31.98% with a quantum concentration ratio of 14.41x on the GaAs cell and 0.75x on the silicon cell when illuminated with the direct AM1.5 spectrum. This system obtains an improvement over the best bandgap PV cell of 20.05%, and has an acceptance angle of +/- 6 deg allowing for tolerant tracking. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)

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Cikalo, Maria Gillian. "Separation and quantification of weakly-absorbing and low-concentration analytes by capillary electrophoresis." Thesis, University of York, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321675.

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Sarmah, Nabin. "Design and performance evaluation of a low concentrating line-axis dielectric photovoltaic system." Thesis, Heriot-Watt University, 2012. http://hdl.handle.net/10399/2656.

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This thesis presents a detailed investigation of the design optimisation and performance analysis of a dielectric concentrator for building façade integration at high latitudes (>55°). Considering the seasonal variation of the sun’s position at these latitudes, a concentrating photovoltaic (CPV) system with stationary concentrators of large acceptance angle and low concentration ratio is a suitable alternative to conventional flat plate photovoltaic (PV) modules. A well designed dielectric asymmetric compound parabolic concentrator (ACPC) is a suitable choice to achieve optimum range of acceptance angles and concentration ratio for building façade integration in the Edinburgh and higher latitudes. A theoretical study of the optical performance shows that a truncated dielectric ACPC with acceptance half-angles of 0o and 55o (termed as DiACPC-55) is the optimum design, when compared to the dielectric ACPC designs with acceptance half angles of (0o and 66o) and (0o and 77o) in Edinburgh and higher latitudes. An increase in the range of acceptance angles is achieved by truncating the concentrator profile. Ray tracing simulations show the DiACPC-55 exhibits the widest range of acceptance angles compared to the other designs. The maximum optical efficiency of the DiACPC-55 is found to be 83%. In addition it is found to have a better intensity distribution at the receiver and a higher total annual energy collection, compared to the other designs. Thermal modelling of a CPV system with the DiACPC-55 concentrator shows that the solar cell and rear plate temperature can reach up to 41.6oC for 1000 W/m2 irradiance, when operating with an average ambient temperature of 10oC. The maximum power ratio of the CPV module (fabricated using the DiACPC-55 concentrator) to a similar non-concentrating counterpart is found to be 2.32, when characterised in an indoor controlled environment using a solar simulator. An average electrical conversion efficiency of 9.5% is measured for the entire range of acceptance angles. The optical loss analysis shows that incident light can escape from the parabolic sides and concentrator-encapsulation interface. The outdoor characterisation of the CPV module with the DiACPC-55 concentrator shows that a maximum power ratio of 2.22 can be achieved on a sunny day. In comparison, a maximum power ratio of 1.9 is observed on a rainy day. These results reveal that the designed dielectric concentrator is capable of collecting 68% of the diffuse radiation. The maximum electrical conversion efficiency of the CPV module in outdoor condition is found to be 9.4%. Module degradation due to the delamination of the solar cell is observed in the long term investigation study, which reduces the module efficiency to 8.6% on a clear sunny day. The fabricated CPV system with the DiACPC-55 concentrator is found to be £190.3/m2 cheaper than similar sized conventional glass-glass laminated modules. Therefore the cost of the CPV module is found to be £0.53/Wp cheaper than the conventional glass-glass laminated modules for building facade integration at high latitudes.

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Dissertations / Theses on the topic 'Concentrating systems'

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