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Manshaei, Leila. "Modelling of Photovoltaic power plantsin SIMPOW." Thesis, KTH, Elektriska energisystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121150.
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This master thesis project represents an improved model of a grid connected three phase, singlestage PV system implemented in SIMPOW program. The proposal model consists of a PVgenerator employing a PWM converter in order to interface the AC network. The main objectiveof the project is to introduce the main components of the represented model as well as therequired controller schemes. In order to achieve the accurate performance of the PV system withrespect to the integration grid, both AC and DC side network are equipped with controllerfacilities, optimizing the system operation. The control facilities, implemented on the DC side,are mainly focusing on regulation of the output DC voltage of the generator depending on therequirements of the system. The newly proposal MPPT model represents an improvedoptimization strategy for the DC voltage extraction corresponding to various environmentalconditions. The AC side controllers are designed considering the PV system dynamiccontribution on the grid as well as its participation in reactive power provision to the network. Tostudy the accuracy of the dynamic operation of the system, several case studies have beenperformed on AC and DC side. The results of those studies have been discussed considering theirsimulation diagrams.
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Schweizer, Christian. "Modelling photovoltaic systems in urban environments." Thesis, De Montfort University, 2000. http://hdl.handle.net/2086/4822.
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Gow, John A. "Modelling, simulation and control of photovoltaic converter systems." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6871.
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The thesis follows the development of an advanced solar photovoltaic power conversion system from first principles. It is divided into five parts. The first section shows the development of a circuit-based simulation model of a photovoltaic (PV) cell within the 'SABER' simulator environment. Although simulation models for photovoltaic cells are available these are usually application specific, mathematically intensive and not suited to the development of power electronics. The model derived within the thesis is a circuit-based model that makes use of a series of current/voltage data sets taken from an actual cell in order to define the relationships between the cell double-exponential model parameters and the environmental parameters of temperature and irradiance. Resulting expressions define a 'black box' model, and the power electronics designer may simply specify values of temperature and irradiance to the model, and the simulated electrical connections to the cell provide the appropriate I/V characteristic. The second section deals with the development of a simulation model of an advanced PVaware DC-DC converter system. This differs from the conventional in that by using an embedded maximum power tracking system within a conventional linear feedback control arrangement it addresses the problem of loads which may not require the level of power available at the maximum power point, but is also able to drive loads which consistently require a maximum power feed such as a grid-coupled inverter. The third section details a low-power implementation of the above system in hardware. This shows the viability of the new, fast embedded maximum power tracking system and also the advantages of the system in terms of speed and response time over conventional systems. The fourth section builds upon the simulation model developed in the second section by adding an inverter allowing AC loads (including a utility) to be driven. The complete system is simulated and a set of results obtained showing that the system is a usable one. The final section describes the construction and analysis of a complete system in hardware (c. 500W) and identifies the suitability of the system to appropriate applications.
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Wang, Yimin. "Modelling physical location based factors of photovoltaic viability." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6367/.
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The aim of this thesis is to model physical location based factors of photovoltaic (PV) viability, including geographical location, dominated climate factors, urban terrain shading and PV panel technologies. We analyze ground measurements from thirteen UK Met Office British weather stations, and ten further weather stations in the US operated by National Solar Radiation Data Base for evidence of climatic effects on annual and seasonal solar radiation over the last 40 years. The impact of the North Atlantic Oscillation on winter solar radiation in the British Isles is explored. We evaluate the accuracies of four solar radiation models - the PVGIS model, UKCP09 model, Liu and Jordan model and Page model - against ground measurements from these thirteen UK Met Office British weather stations. A three-dimensional (3D) SOlar RAdiation Model (SORAM) is presented for evaluating the potential direct and diffuse solar radiation aggregated at a point location in an urban area. By using ray-tracing algorithm, SORAM is capable of taking into account terrain shading. We also present a mobile application that has the same aim as SORAM. However, instead of using a 3D city map, the embedded shading detection algorithm is based on image processing. An analytical model of externally-coated, rectangular and cylindrical luminescent solar concentrators (LSCs) have been developed. These LSCs are able to estimate the residual intensity as a function of wavelength, concentration of luminescent dye and device dimension.
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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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Czekala, Piotr. "Modelling of molecules on surfaces and thin-film photovoltaic absorbers." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/16755/.
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In this thesis a range of phenomena related to molecular adsorption on silicon surfaces is investigated. The majority of the studies are performed in response to experimental results, where, using newly developed methods within the framework of density functional theory, we aim to elucidate some of the underlying physics as well as test the performance of the chosen methodology. The studies cover a range of subjects such as molecularly mediated pinning of surface geometry, single molecular adsorptions, molecule migration via exited states and finally an analysis of coverage dependent adsorption phenomena, where interactions between molecules are mediated by the surface or enacted via dipole interactions. The main molecules of our simulations were water, ethylene, acetylene, and benzene, as well as halogenated hydrocarbons. We studied processes at two different surfaces, the Si(111)-7 x 7 surface, and the Si(100)-c(4 x 2) surface. Finally we simulated and characterized one type of grain boundary observed experimentally for a set of photovoltaic absorbers (CuInSe_{2}) and kesterite and stannite(Cu_{2}ZnSnSe_{4} or Cu_{2}ZnSnS_{4}) in order to resolve the open question of how these grain boundaries influence efficiencies of the photovoltaic device.
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Aseeri, Ahmed. "Modelling and simulation of fuel cell/photovoltaic hybrid power system." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/8280.
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Due to an ever increasing demand for power consumption and a rising public awareness of the impact on the environment, renewable energy based on Hybrid Power Systems (HPS) (e.g. fuel cell, wind or solar) to supply electricity has attracted a growing research interest. Photovoltaic (PV) power generation systems are among the most promising renewable energy technology solutions. Fuel Cell (FC), on the other hand, is emission-free and quieter than hydrocarbon fuel-powered engines. It saves fuel and is cleaner for the environment. Such systems can generate electricity from clean sources to power loads located in inaccessible or remote areas.
The aim of this thesis is to investigate the potential for utilising an FC/PV hybrid power system to provide power for a water pump, which supply an elevated water tank (6,500 litres/day consumption) to a small community located in a remote area. The HPS consists of a photovoltaic solar panel, a 1.2 KW Nexa Proton Exchange Membrane Fuel Cell (PEMFC), a Lead acid battery bank, a bidirectional DC/DC converter, one directional DC/DC converter and a water pump. The thesis will commence with a literature review, giving an overview of energy demand and future trend, describing the different HPS configurations and giving some examples of similar projects carried out by other researchers and organisations. A system component description is also covered. The thesis will then move on to describing the HPS simulation model development using Matlab/Simulink simulation environment, concluding with the test cases used to validate the model based on the 1.2 KW Nexa PEMFC and PV panels.
In the case study, the system utilizes photovoltaic (PV) as the primary power generator, PEMFC as the secondary back-up power generator and a battery bank (to store any excess power) as power storage device. The advantage of the proposed system is that, in addition to being environmentally friendly, it also has lower maintenance costs, noise and carbon footprint. Two main scenarios were explored to validate the hybrid system performance, at two different geographical and environmental conditions.
The first case is based in Saudi Arabia, where it is hot and sunny for most of the year. This scenario permits higher utilization of the power generated from the PV cells and reduces the dependence on power produced by the fuel cell. The second case scenario is based in the UK, where it is cold and cloudy for most of the year. The Sunlight here is at minimum, leading to higher dependence on the fuel cells for the system operation.
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Black, Jonathan Paul. "Mathematical modelling of electronic contact mechanisms in silicon photovoltaic cells." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:ff671215-5f05-4ef0-a876-3f474a8450c9.
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In screen-printed silicon-crystalline solar cells, the contact resistance of a thin interfacial glass layer between the silicon and the silver electrode plays a limiting role for electron transport. The motivation of this project is to gain increased understanding of the transport mechanisms of the electrons across this layer, which can be exploited to provide higher performance crystalline silicon solar cells. Our methodology throughout is to formulate and analyse mathematical models for the electron transport, based on the drift diffusion equations. In the first chapter we outline the problem and provide a summary of relevant theory. In Chapter 2 we formulate a one-dimensional model for electron transport across the glass layer, that we solve both numerically and by employing asymptotic techniques. Chapter 3 extends the model presented in Chapter 2 to two dimensions. To solve the two-dimensional model numerically we devise and validate a new spectral method. The short circuiting of current through thinner regions of the glass layer enables us to find limiting asymptotic expressions for the average current density for two different canonical glass layer profiles. In Chapter 4 we include quantum mechanical effects into the one-dimensional model outlined in Chapter 2 and find that they have a negligible effect on the contact resistance of the glass layer. We model the boundary effects present at the silicon emitter-glass interface in Chapter 5. Finally, in Chapter 6 we summarise our key results, suggest possible future work, and outline the implications of our work to crystalline silicon solar cell manufacturers.
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Bisconti, Raffaella. "Optical modelling and optimisation of Spheral Solar'T'M Cells." Thesis, Northumbria University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245206.
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Wu, Xiaofeng. "Fast spatially-resolved electrical modelling and quantitative characterisation of photovoltaic devices." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/18018.
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An efficient and flexible modelling and simulation toolset for solving spatially-resolved models of photovoltaic (PV) devices is developed, and its application towards a quantitative description of localised electrical behaviour is given. A method for the extraction of local electrical device parameters is developed as a complementary approach to the conventional characterisation techniques based on lumped models to meet the emerging demands of quantitative spatially-resolved characterisation in the PV community. It allows better understanding of the effects of inhomogeneities on performance of PV devices. The simulation tool is named PV-Oriented Nodal Analysis (PVONA). This is achieved by integrating a specifically designed sparse data structure and a graphics processing unit (GPU)-based parallel conjugate gradient algorithm into a PV-oriented numerical solver. It allows more efficient high-resolution spatially-resolved modelling and simulations of PV devices than conventional approaches based on SPICE (Simulation Program with Integrated Circuit Emphasis) tools in terms of computation time and memory usage. In tests, mega-sub-cell level test cases failed in the latest LTSpice version (v4.22) and a PSpice version (v16.6) on desktop PCs with mainstream hardware due to a memory shortage. PVONA efficiently managed to solve the models. Moreover, it required up to only 5% of the time comparing the two SPICE counterparts. This allows the investigation of inhomogeneities and fault mechanisms in PV devices with high resolution on common computing platforms. The PVONA-based spatially-resolved modelling and simulation is used in various purposes. As an example, it is utilised to evaluate the impacts of nonuniform illumination profiles in a concentrator PV unit. A joint optical and electrical modelling framework is presented. Simulation results suggest that uncertainties introduced during the manufacturing and assembly of the optical components can significantly affect the performance of the system in terms of local voltage and current distribution and global current-voltage characteristics. Significant series resistance and shunt resistance effects are found to be caused by non-uniformity irradiance profiles and design parameters of PV cells. The potential of utilising PVONA as a quality assessment tool for system design is discussed. To achieve quantitative characterisation, the PVONA toolset is then used for developing a 2-D iterative method for the extraction of local electrical parameters of spatially-resolved models of thin-film devices. The method employs PVONA to implement 2-D fitting to reproduce the lateral variations in electroluminescence (EL) images, and to match the dark current-voltage characteristic simultaneously to compensate the calibration factor in EL characterisations. It managed to separate the lateral resistance from the overall series resistance effects. The method is verified by simulations. Experimental results show that pixellation of EL images can be achieved. Effects of local shunts are accurately reproduced by a fitting algorithm. The outcomes of this thesis provide valuable tools that can be used as a complementary means of performance evaluation of PV devices. After proper optimisation, these tools can be used to assist various analysis tasks during the whole lifecycle of PV products.
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Syres, Karen Louise. "Molecular adsorption on TiO2 surfaces : modelling potential biomedical and photovoltaic devices." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/molecular-adsorption-on-tio2-surfaces-modelling-potential-biomedical-and-photovoltaic-devices(14c1f1a6-7650-43e2-b8cc-9c9e102f6923).html.
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This thesis describes molecular adsorption on single crystal anatase (101) and rutile (110) TiO2 surfaces and TiO2 nanoparticles using photoemission and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. DFT calculations were carried out in order to complement the experimental data. The adsorption of dopamine and pyrocatechol on single crystal TiO2 surfaces was investigated with photoemission and NEXAFS and indicates the molecules adsorb in a bidentate mode following deprotonation of the hydroxyl groups. NEXAFS analysis of pyrocatechol adsorption on the rutile (110) and anatase (101) TiO2 surfaces shows the plane of the aromatic ring to be oriented at 23˚±8˚ and 27˚±6˚ from the surface normal, respectively. Dopamine adsorbed on the anatase TiO2 (101) surface was found to adsorb with the plane of the ring approximately normal to the surface. Adsorption of pyrocatechol and dopamine on anatase TiO2 (101) gave rise to a feature below the main pi* peak, not observed when pyrocatechol was adsorbed on rutile TiO2 (110). This feature was replicated in DFT calculations of both dopamine and pyrocatechol adsorbed on an anatase TiO2 cluster, but was not present in calculations of the free molecules. The new states are found to be located on the TiO2 surface, which may allow direct charge-transfer from the molecule to the surface. Simulated NEXAFS spectra from the cluster showed good agreement with the experimental data in the pi* region for the molecule-anatase TiO2 (101) system. The rutile experimental data showed good agreement with calculations of the free molecule in terms of the pi* peak separation. Charge-transfer studies of pyrocatechol adsorbed on the rutile TiO2 (110) surface indicate that charge-transfer could be occurring from the LUMO, LUMO+1 and LUMO+2 in the pyrocatechol molecule. The charge transfer time for this system was found to be < 9.0 ± 2.0 fs. XPS results for functionalised TiO2 nanoparticles show that dopamine (DA) molecules adsorb intact and bond through both oxygen atoms. The attachment of PEG (polyethylene glycol) and Pluronic was investigated. PEGme-DA (terminated with methyl) and DA-PEG-DA showed attachment to the nanoparticles occurs through one end of the chain. DA-Pluronic-DA may attach through both DA molecules but this could not be proved conclusively. Adsorption of malonic acid on rutile TiO2 (110) showed that the molecule degraded under the synchrotron beam and formed acetate and/or formate. It was found that dipping this surface into a ruthenium di-2,2'-bipyridyl-4,4'-dicarboxylic acid diisocyanate-dye solution in air appeared to displace the adsorbed species, replacing them with the dye.
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Zarmai, Musa Tanko. "Modelling of solder interconnection's performance in photovoltaic modules for reliability prediction." Thesis, University of Wolverhampton, 2016. http://hdl.handle.net/2436/617782.
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Standard crystalline silicon photovoltaic (PV) modules are designed to continuously convert solar energy into electricity for 25 years. However, the continual generation of electricity by the PV modules throughout their designed service life has been a concern. The key challenge has been the untimely fatigue failure of solder interconnections of solar cells in the modules due to accelerated thermo-mechanical degradation. The goal of this research is to provide adequate information for proper design of solar cell solder joint against fatigue failure through the study of cyclic thermo-mechanical stresses and strains in the joint. This is carried-out through finite element analysis (FEA) using ANSYS software to develop the solar cell assembly geometric models followed by simulations. Appropriate material constitutive model for solder alloy is employed to predict number of cycles to failure of solder joint, hence predicting its fatigue life. The results obtained from this study indicate that intermetallic compound thickness (TIMC); solder joint thickness (TSJ) and width (WSJ) have significant impacts on fatigue life of solder joint. The impacts of TIMC and TSJ are such that as the thicknesses increases solder joint fatigue life decreases. Conversely, as solder joint width (WSJ) increases, fatigue life increases. Furthermore, optimization of the joint is carried-out towards thermo-mechanical reliability improvement. Analysis of results shows the design with optimal parameter setting to be: TIMC -2.5μm, TSJ -20μm and WSJ -1000μm. In addition, the optimized model has 16,264 cycles to failure which is 18.82% more than the expected 13,688 cycles to failure of a PV module designed to last for 25 years.
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Sokolov, Michael. "Small-signal modelling of maximum power point tracking for photovoltaic systems." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/39348.
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In grid connected photovoltaic (PV) generation systems, inverters are used to convert the generated DC voltage to an AC voltage. An additional dc-dc converter is usually connected between the PV source and the inverter for Maximum Power Point Tracking (MPPT). An iterative MPPT algorithm searches for the optimum operating point of PV cells to maximise the output power under various atmospheric conditions. It is desirable to be able to represent the dynamics of the changing PV power yield within stability studies of the AC network. Unfortunately MPPT algorithms tend to be nonlinear and/or time-varying and cannot be easily combined with linear models of other system elements. In this work a new MPPT technique is developed in order to enable linear analysis of the PV system over reasonable time scales. The new MPPT method is based on interpolation and an emulated-load control technique. Numerical analysis and simulations are employed to develop and refine the MPPT. The small-signal modelling of the MPPT technique exploits the fact that the emulated-load control technique can be linearised and that short periods of interpolation can be neglected. A small-signal PV system model for variable irradiation conditions was developed. The PV system includes a PV module, a dc-dc boost converter, the proposed controller and a variety of possible loads. The new model was verified by component-level time-domain simulations. Be cause measured signals in PV systems contain noise, it is important to assess the impact of that noise on the MPPT and design an algorithm that operates effectively in pr esence of noise. For performance assessment of the new MPPT techniques, the efficiencies of various MPPT techniques in presence of noise were compared. This comparison showed superiority of the interpolation MPPT and led to conclusions about effective use of existing MPPT methods. The new MPPT method was also experimentally tested.
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Ebrahim, Mila. "Performance Evaluation of a Photovoltaic/Thermal (PVT) Collector with Numerical Modelling." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302122.
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In Photovoltaic/Thermal (PVT) technology, both PV and solar thermal technology are integrated in the same module for simultaneous electricity and heat production. Research has shown that there are multiple benefits from integrating PVT collectors with a ground source heat pump (GSHP) system, since it allows for seasonal storage of thermal energy over the year. Furthermore, it leads to reduced operating temperatures for the PVT collectors which can increase efficiency and lifetime. The aim of this study is to present the electric and thermal performance of a PVT collector developed by Solhybrid i Småland AB, for different environmental and fluid inlet conditions that can occur when PVT collectors are connected to a GSHP system. Furthermore, the performance of this PVT design is evaluated with ASHRAE (Standard 93-2003), to allow for comparison with other PVT collector designs, with values on the overall heat loss coefficient (UL) and heat removal factor (FR). The modelling tool used for the study is the software COMSOL Multiphysics, which uses the finite element method to solve the partial differential equations in heat transfer and fluid flow problems. Based on the performance curves, the thermal and electrical efficiency of the collector is approximately 48.0-53.4% and 19.0-19.2% respectively at a reduced temperature of zero and irradiance levels of 800-1000 W/m2 for the mass flow rate of 0.026 kg/sm2 which was determined as most suitable to increase thermal performance. Furthermore, these results resulted in a heat removal factor (FR) and overall heat loss coefficient (UL) of 0.56-0.62 and 53.4-53.5 W/m2 K respectively. The results on the performance of the PVT collector in different weather conditions shows that the inlet water temperature can significantly affect operating time and the amount of thermal energy that can be extracted during the year, especially if the collector operates in a colder climate like Sweden. To assess the accuracy of the created model, future work includes experimental testing of the studied PVT collector.En panel med kombinerad teknik av både solceller och termisk solfångare (PVT) kan producera både elektricitet och värme samtidigt. Forskning har visat att det kan finnas flera fördelar med att integrera PVT-paneler med ett bergvärmesystem, eftersom det mjliggör lagring av termisk energi över året. Dessutom leder ett sådant system till lägre drifttemperaturer som kan öka PVT-panelens effektivitet och livslängd. Syftet med studien är att presentera den elektriska och termiska prestandan av en PVT-panel utvecklat av Solhybrid i Småland AB för olika driftförhållanden som kan uppstå på grund av olika väderförhållanden och inlopps-temperaturer när panelerna är kopplade till ett bergvärmesystem. Vidare utvärderas prestandan för denna panel med ASHRAEmetoden (standard 93-2003), för att möjliggöra jämförelse med andra PVT-paneler. Modelleringsverktyget som använts i studien är mjukvaran COMSOL Multiphysics, som använder finita elementmetoden för att lösa partiella differentialekvationer i värmeöverförings-och flödesproblem. Baserat på prestandakurvorna som presenteras i resultatet, är den termiska och elektriska verkningsgraden approximativt 48.0-53.4% respektive 19.0-19.2% för en reducerad temperatur med värdet noll, en solstrålning mellan 800-1000 W/m2, för en massflödeshastighet på 0.026 kg/sm2 som beslutades som den mest lämpliga för att öka den termiska prestandan. Resultaten resulterade i en värmeavledningsfaktor (FR) och total värmeförlustkoefficient (UL) på 0.56-0.62 respektive 53.4-53.5 W/m2 K. Resultaten på PVT-panelens prestanda under olika väderförhållanden visar att vattnets inloppstemperatur kan påverka drifttiden och mängden termisk energi som kan extraheras under året avsevärt, speciellt i nordiskt klimat. För att bedöma korrektheten i resultaten och den skapade modellen rekommenderas experimentell testning av den studerade PVT-panelen.
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Martin, C. M. "Modelling the Effect of the Interface Morphology in Organic-Inorganic Photovoltaic Devices." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504434.
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Braun, Felix Maximilian. "Modelling of light-trapping structures and their application in organic photovoltaic devices." Thesis, University College London (University of London), 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437362.
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Brivio, Federico. "Atomistic modelling of perovskite solar cells." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.698992.
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This thesis focuses on the study of hybrid perovskites properties for the purposes of photovoltaic applications. During the almost four years PhD project that has lead to this thesis the record photovoltaic efficiency for this technology has in- creased from 10.9% to 22.1%. Such a significant pace of development can be com- pared with few other materials. It is for this reason that hybrid perovsites have at- tracted impressive research efforts. We approached the study of such unique ma- terials using computational ab-initio techniques, and in particular Density Func- tional Theory. We considered different materials, but most of the attention was concentrated on MAPI (CH 3 NH 3 PbI 3 ). The results are divided in three chapters, each exploring a different material prop- erty. The first chapter reports the electronic structure of the material bulk, sur- faces, and other electronic-related properties such as the rotation barrier for the organic component and the Berry phase polarization. The second chapter focuses on the vibrational properties primary employing the harmonic approximation but also extends to the quasi-harmonic approximation. The outcome of these calculations permitted us to calculate theoretical IR and Ra- man spectra which are in good agreement with different experimental measure- ments. The quasi-harmonic approximation was used to calculate temperature dependent properties, such as the Grüneisen parameter, the thermal dependence of heat capacity and the thermal volumetric expansion. The third and last chapter reviews the thermodynamic properties of binary halide compounds. The cobination of ab-initio calculations with the generalised quasi- chemical approximation has allowed to study the stability of mixed composition perovskites. The results certified a set of stable structures that could stand at the base of observed phenomena of photo-degradation of hybrid perovskite based devices. All three chapters have been written to understand the chemical and physical behaviour of hybrid perovskites and to extended and contribute to the under- standing of experimental work.
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Lam, King-hang. "Techniques for dynamic modelling of BIPV in supporting system design and BEMS." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39558460.
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Quintana, Samer. "Building integrated photovoltaic (BIPV) modelling for a demo site in Ludvika based on building information modelling (BIM) platform." Thesis, Högskolan Dalarna, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-29078.
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This thesis aims to design and simulate a building integrated photovoltaic (BIPV) system for three demo buildings in Ludvika, Sweden, which is part of the Energy- Matching’s project under the European H2020 research scheme. A literature review was firstly conducted in the area of energy scenarios, engineering tools, methodologies and the workflows in design and building energy modelling. Then, this thesis developed the three-dimensional (3D) building models of the demo site, based on the Revit – a building information modelling (BIM) tool. Next, the PVSITES tool was considered as the main approach to simulate and optimize the BIPV system. Results on the energy output of the dedicated BIPV system, as well as financial costs, were finally obtained. It was found that the optimal location for the BIPV system was on the three buildings south and east faced roofs, with a total area of approximately 800 meters squared (m2) and a yearly irradiance potential between 1020 kilowatts hours per meter squared (kWh/m2) and 925 kWh/m2 respectively. The simulation showed that this BIPV system of 615 m2 with a power of 36 kilowatts-peak (kWp) could yield a maximum of 29,000 kilowatts hours per year (kWh), a 5% of the total yearly energy demand of the building and over the summer, this percentage increases considerably. With the estimated standards costs, the BIPV system have a 12 years payback period and 61% investment ratio over a 20 years period, concluding that a BIPV system on the Ludvika demo building is a feasible project, in terms of energy potential and as well as economically. This thesis also concludes that performing the BIPV simulation on the BIM platform is both reliable and flexible, and also has the potential to be reused, refined and scaled up.
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Gabr, Ahmed. "Modelling and Characterization of Down-Conversion and Down-Shifting Processes for Photovoltaic Applications." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35048.
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Down-conversion (DC) and down-shifting (DS) layers are optical layers mounted on the top surface of a solar cell that can potentially increase the solar cell efficiency. The effect of DC and DS layers to enhance the performance of single-junction solar cells has been studied by means of simulation and experimental work. In this thesis a model is developed to study the effects of DC and DS layers by modifying the incident spectrum. The effect of the layers on ideal cells as well as commercial grade silicon and CIGS solar cells that are modeled in a device simulator is examined.
Silicon nanocrystals (Si-nC) embedded in a silicon dioxide matrix to act as a DS layer were fabricated and characterized at McMaster University as part of this project. The measured optical properties as well as the photoluminescence measurements are used as input parameters to the optical model. The enhancement due to the Si-nC when coupled to silicon and CIGS solar cells is explored. Beside the DC and DS effects, there is also disturbance to the surface reflections due to the addition of a new layer to the top surface and is referred to as antireflection coating (ARC) effect. For the simulated silicon solar cell under the standard AM1.5G spectrum (1000W/m2), a maximum increase in Jsc of 8.4% is achieved for a perfect DS layer as compared to a reference cell, where 7.2% is due to ARC effect and only 1.2% is due to DS effect. On the other hand, there is an increase in Jsc of 19.5% for the CIGS solar cell when coupled to a perfect DS layer. The DS effect is dominant with 18%, while the ARC effect contributes only 1.5% to the total Jsc enhancement.
Accurately characterizing DS layers coupled to solar cell requires knowledge of optical properties of the complete structure. Internal quantum efficiency is an important tool for characterizing DS systems, nevertheless, it is rarely reported. In addition, the ARC effect is not experimentally decoupled from the DS effect. In this work, a straightforward method for calculating the active layer contribution that minimizes error by subtracting optically-modeled electrode absorption from experimentally measured total absorption.
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Fialho, Luís André Pereira. "Photovoltaic generation with energy storage integrated into the electric grid: modelling, simulation and experimentation." Doctoral thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/25361.
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Esta tese apresenta o trabalho e resultados da investigação desenvolvida sobre conversão fotovoltaica com armazenamento de energia integrado em rede elétrica. Começa por apresentar a modelação, simulação e validação da conversão fotovoltaica e inversores com injeção para a rede. Descreve também seguidamente o processo de conceção, construção, comissionamento e desenvolvimento experimental das infraestruturas hoje existentes na Cátedra Energias Renováveis da Universidade de Évora, no que diz respeito às duas microgrids desenvolvidas no âmbito do projeto europeu PVCROPS. Estas microgrids são compostas, de forma geral, por um elemento de produção fotovoltaica, um elemento de armazenamento de energia, uma ligação à rede e um sistema de controlo e datalogging. Relativamente ao armazenamento de energia, esta tese aborda e caracteriza ainda as duas tecnologias instaladas: a bateria de iões de lítio e a bateria de fluxo redox de vanádio. Estas microgrids servem assim para implementação e validação de uma estratégia de gestão de energia tendo como objetivo a maximização do autoconsumo, cujos conteúdos são apresentados no capítulo 4. Depois das conclusões, no último capítulo, apontam-se ainda as linhas de investigação futuras de maior potencial, na sequência do trabalho desenvolvido e apresentado nesta tese; Photovoltaic generation with energy storage integrated into the electric grid: Modelling, simulation and experimentation
Abstract:
This thesis presents the work and results of the research developed on photovoltaic conversion with energy storage integrated into the electric grid. It begins by presenting the modeling, simulation and validation of the photovoltaic conversion and inverters with injection into the electric grid. It also describes the process of design, construction, commissioning and experimental development of the existing infrastructures in the Renewable Energies Chair of the University of Évora, with respect to the two microgrids developed under the European project PVCROPS. These microgrids are generally composed by a photovoltaic production element, an energy storage element, a grid connection and a control and datalogging system. Regarding energy storage, this thesis also discusses and characterizes the two installed technologies: the lithium-ion battery and the redox-flow vanadium battery. These microgrids thus serve to implement and validate an energy management strategy with the objective of maximizing self-consumption, the contents of which are presented in Chapter 4. Following the conclusions, in the last chapter are pointed the future research lines of greater potential, following the work developed and presented in this thesis.
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Vanden, Eynde Nicholas. "Modelling of a stand alone photovoltaic system with dedicated hybrid battery energy storage system." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/11932.
Full textAbstract:
Includes abstract.Includes bibliographical references.
The purpose of this thesis project was to model and simulate a stand-alone photovoltaic (PV) plant that utilized the maximum power point tracking (MPPT) technique and included a hybrid battery energy storage system (BESS). The model consisted of five main components namely; the photovoltaic module, maximum power point tracking technique, hybrid battery energy storage system, controller and load.
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Young, Clinton. "Analysis and optimisation through mathematical modelling: Muresk farm photovoltaic reverse osmosis water treatment plant." Thesis, Young, Clinton (2020) Analysis and optimisation through mathematical modelling: Muresk farm photovoltaic reverse osmosis water treatment plant. Honours thesis, Murdoch University, 2020. https://researchrepository.murdoch.edu.au/id/eprint/57216/.
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Photovoltaic reverse osmosis water treatment units can be deployed into remote regions to provide remote communities with a clean water source without the need for on site electricity supply to operate. Optimisation of these units has the potential to maximise the output of purified water and to improve the overall effectiveness of the PVRO unit once it has been deployed. The aim of this project is to develop a mathematical model for the optimisation of the Muresk PVRO unit. This is achieved using a local monitoring system that can log the operational data of the PVRO unit and utilising this data to validate and tune a Microsoft Excel based mathematical model of the Muresk PVRO unit.
In this project an ESP32 microcontroller running an Arduino program was used to log the electrical and water flow data from the PVRO unit to a ThingSpeak IOT portal and a local SD card. A mathematical model of the Muresk PVRO system was developed, and two months of data were compared with the data from the monitoring unit to tune and validate the model. With the model tuned the mathematical model was used to investigate optimising the PVRO output by adjusting the tilt angle of the solar array. By increasing the array tilt from 30 degrees to 45-degrees the daily minimum output improved by 9% with a marginal loss of 1% to the annual water output. This increases the suitability of the unit to applications where a consistent output of clean water is more desired than just maximising the annual output.
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Chiodetti, Matthieu. "Bifacial PV plants: performance model development and optimization of their configuration." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172516.
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Bifacial solar modules can absorb and convert solar irradiance to current on both their front side and back side. Several elements affects the bifacial yield, especially the ground albedo around the system or the installation configuration. In this document, investigations carried out at EDF R&D facilities regarding the use of bifacial modules in large scale PV farm are presented. Tests on the outdoor facilities were conducted to validate and improve a bifacial stand model developed under a Dymola/Modelica environement. Furthermore, a global optimization method was implemented to determine the optimal configuration of a large bifacial plant with modules facing south. Investigations showed the importance of a new albedo model to accurately evaluate the irradiance received on the rear side. The new model shows a relative error on the rear irradiance under 5% when compared with experimental data. Techno-economical optimization of a bifacial plant was conducted at different locations and for different ground albedo. The results shows that the gain on the specific production can vary between 7.2 and 14.2% for a bifacial plant when compared with a monofacial plant. Bifacial plants are expected to become more profitable than monofacial plants in some of the cases tested when their module cost will reach 68 c€/Wp.
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Lam, King-hang, and 林勁恆. "Techniques for dynamic modelling of BIPV in supporting system design and BEMS." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39558460.
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Hofmann, Martin [Verfasser]. "Analysis and improvement of irradiance modelling algorithms for the simulation of photovoltaic systems / Martin Hofmann." Hannover : Gottfried Wilhelm Leibniz Universität, 2019. http://d-nb.info/1196809119/34.
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Lammert, Gustav [Verfasser]. "Modelling, Control and Stability Analysis of Photovoltaic Systems in Power System Dynamic Studies / Gustav Lammert." Kassel : Kassel University Press, 2019. http://d-nb.info/1196034125/34.
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Boreland, Matt School of Electrical Engineering UNSW. "Laser Crystallisation of Silicon for Photovoltaic Applications using Copper Vapour Lasers." Awarded by:University of New South Wales. School of Electrical Engineering, 1999. http://handle.unsw.edu.au/1959.4/17190.
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Thin film silicon on low temperature glass substrates is currently seen as the best path toreduce the $/W cost of photovoltaic (PV) modules. However, producing thin film polysilicon, on glass, is an ongoing research challenge. Laser crystallisation of a-Si is one of the possible methods. Typically excimer (XMR) lasers are used for laser crystallisation. This thesis introduces the copper vapour laser (CVL) as a viable alternative for thin film photovoltaic applications. The CVL, like the XMR, is a high powered, pulsed laser. However, the CVL has higher pulse rates (4-20kHz), better beam quality and a visible wavelength output (578 & 511nm). Preliminary experiments, using 600K-heated silicon-on-quartz samples, confirmed that CVL crystallisation can produce area weighted average grain size of 0.1-0.15??m, which is comparable to results reported for XMR??? s. Importantly, the CVL results used thicker films (1??m), which is more applicable to thin photovoltaic devices that need 1-10??m of silicon to be viable. The CVL??? s longer wavelength and therefore longer penetration depth (1/alpha) are proffered as the main reason for this result. Extensive laser-thermal modelling highlighted further opportunities specific to CVL crystallisation. Through-the-glass doublesided irradiation was shown in simulations to reduce thermal gradients, which would enhance crystal growth. The simulations also produced deeper melts at lower surface temperatures, reducing the thermal stress on the sample. Subsequent experiments, using silicon-on-glass, confirmed the benefit of through-the-glass doublesided irradiation by maintaining grain sizes without the usual need for substrate heating. Furthermore, Raman analysis showed that doublesided crystallisation achieved full depth crystallisation, unlike single side irradiation which produced partial crystallisation. A new mode of crystallisation, stepwise crystallisation, was also postulated whereby a series of CVL pulses could be used to incrementally increase the crystallisation depth into the silicon. Simulations confirmed the theoretical basis of the concept, with HeNe Raman spectroscopy and analysis of surface grain sizes providing indirect experimental support. The CVL??? s ability to crystallise thicker films more directly applicable to photovoltaic devices secures its viability as an alternative laser for photovoltaic applications. The through-the-glass doublesided irradiation and the stepwise crystallisation provide additional potential for increased process flexibility over XMR???s.
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Marzooghi, Hesamoddin. "Modelling and Stability Assessment of Future Grid Scenarios." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15408.
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With the increased penetration of intermittent renewable energy sources (RESs) in future grids (FGs), balancing between supply and demand will become more dependent on demand response (DR) and energy storage. So far, FG feasibility studies, especially those claiming a long-term view, typically do not model the electrical network and/or the effect of DR. Thus, in this thesis, we first present a simulation platform for performance and stability assessment of FG scenarios. The platform considers market simulation, load flow calculation and stability assessment together. Using the platform, we illustrate how displacing conventional generators with RESs, especially inverter-based and intermittent RESs, could have significant impacts on performance and stability of FGs, confirming the importance of stability assessment for FG feasibility studies. Second, to carry out accurate stability analysis of FG scenarios, we need a representation of the aggregate demand including the effect of emerging demand-side technologies (distributed generation (DG), DR and storage). In this research, we propose generic demand models including the aggregated impact of price-responsive users equipped with emerging demand-side technologies (prosumers). The proposed models capture essential behaviour of the prosumers without giving lots of detail which is costly in repeated use for applications such as scenario comparisons. So, such models demand some simplifications, just as conventional generic load modelling did. The proposed frameworks are based on the unit commitment (UC) problem aiming to minimise the system cost. The conventional demand model in the associated optimisation formulations are augmented by including the aggregated influences of prosumers equipped with rooftop photovoltaics (PV)-battery systems. It is noted that as the frameworks are generic, they are capable of easy integration of other demand-side technologies as well. The developed frameworks are intended specifically for modelling net demand by including the impact of prosumers in FG scenario studies. Nevertheless, they do not assume any particular market structure. As such, they are not suitable for modelling of existing electricity markets, but rather their aim are to capture the behaviour of future electricity markets provided a suitable market structure is adopted. Finally, the impact of prosumers on performance and voltage stability of the Australian National Electricity Market (NEM) is studied with the increased penetration of RESs in the grid. We have considered different penetrations of RESs, and assessed the influence of different penetrations of prosumers on the balancing, loadability and voltage stability of the NEM.
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Vika, Håvard Breisnes. "Modelling of Photovoltaic Modules with Battery Energy Storage in Simulink/Matlab : With in-situ measurement comparisons." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26128.
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The use of renewable energy sources is increasing and will play an important role in the future power systems. The unpredictable and fluctuating nature of solar power leads to a need for energy storage as the prevalence increases.A five parameter model of PV modules has been implemented in Simulink/Matlab. The parameters of the model are determined by an approximation method using data sheet values. Inputs to the model include light intensity and ambient temperature. The outputs are any measurements of interests as well as power, cell temperature and voltage. Effects of varying the model parameters are demonstrated. A maximum power point tracking algorithm is used to keep the voltage at the maximum power point at all times.A battery model based on discharge curve fitting is implemented. The model is based on a fundamental battery cell which can be modified to construct many different module configurations. Power smoothing algorithms which average the input over a set time, are used to provide a power reference to the battery system.The PV model power output is compared to in-situ measurements by giving the model inputs of measured irradiance profile and ambient temperature. Measurements of two different days, one with little variation in irradiance and one with a lot of variation, are used to shed light on different effects. The difference between the output of the simulation and the measured values is very small, in the range of a few percent, especially when there is little variation in irradiance. Large peaks in difference are probably caused by the maximum power point tracking not being able to follow rapidly changing conditions.The approximation used in the modelling of cell temperature deviates significantly from the measured cell temperature. This is confirmed as one of the largest causes of deviance by running simulations with actual measured cell temperature.Power smoothing efficiency is demonstrated with different battery module sizes. Changing the power smoothing algorithm parameters to suit the battery capacity is shown to be effective in providing as good smoothing as possible within battery constraints.
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Zacharopoulos, Aggelos. "Optical design modelling and experimental characterisation of line-axis concentrators for solar photovoltaic and thermal applications." Thesis, University of Ulster, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342344.
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Adeleke, Adedayo Kelvin. "Web-based GIS modelling of building-integrated solar photovoltaic system for the City of Cape Town." Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29181.
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Population increase in African cities have made it hard to reduce their ecological footprint and attain self-sustainability. This made the United Nations to put forward the seventeen sustainable development goals. Three of these goals centre on provision of clean energy and reduction of reliance on fossil fuels. It is therefore important for cities in Africa to chart a path of attaining sustainability. Consequently, the city of Cape Town is leading the drive for a greener city and self-sustainability in energy. Solar energy, which is regarded as a clean and renewable source of energy, makes it possible to generate electricity by using photovoltaics technology. However, the problem of creating awareness as to the potentials of building-integrated solar photovoltaic system persists. The study is aimed at using remote sensing and Geographic Information Systems (GIS) techniques in creating awareness about the potentials of building rooftops for solar photovoltaics installations in an urban setting. In achieving this, Light Detection and Ranging (LiDAR) data and aerial imagery are sourced from City of Cape Town municipality to serve as the primary data input. Four phases of analysis are involved: (1) extraction of whole building roof outline and its roof planes, using the integration of LiDAR-derived products and aerial imagery, in order to determine the surface area of the roof planes. This is achieved by developing a unique two-in-one, object-based classification rulesets; (2) estimating and validating the global solar radiation incidence on each roof plane, using a LiDAR-derived elevation model in a python script utilizing the GRASS script library; (3) evaluating the solar photovoltaic potential of each roof plane, using inputs from two previous phases to create a solar photovoltaic potential database; and (4) deploying the solution online to create awareness, by utilizing JavaScript and Hypertext Mark-up Language (HTML) to implement a map mashup, which incorporates tile map and table services. This results in a web-based solution, which can be queried to retrieve information about the solar photovoltaic potential of a building roof. From the results generated and the system developed, it becomes possible to remotely and sufficiently evaluate buildings in the city for solar photovoltaic potentials, designs and installations. Thereby reducing reliance on the fossil fuel generated electricity and improving the self-sustainability of the city.
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Clemente, Andres. "Design and modelling of a photovoltaic driven fan solar air heater for drying woodchip in Scotland." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/4417.
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In the wood fuel supply chain, the water contained in the product determines one aspect of the quality of the wood. It is necessary to reduce the moisture content (MC) of the wood in order to reduce transport and storing costs and also to increase the heating value of the wood. In this thesis a solar thermal application has been developed to dry woodchips using exclusively solar energy. The novel solar woodchip dryer comprises a small woodchip dryer and a solar air thermal system (SATS) to increase the temperature of the drying air. The particularity of this woodchip dryer is that the input air flow is governed by a photovoltaic driven fan. Based on the experimental results obtained, the woodchip dryer and the SATS thermal performance were modelled and a simulation tool for predicting the dried woodchip production during a period of time has been developed. Two small capacity dryers, a thin and a thick layer dryer, have been designed and built to dry woodchip based on the flow capacity of the SATS. The drying performances are studied for both configurations comparing the drying times, drying rates and efficiencies at different test conditions. The drying curves obtained from each test are modelled as a function of key parameters, temperature and velocity employing the Page model equation. Based on the experimental results, a drying model has been successfully developed to predict the MC when the woodchip dryer operates within a range of drying conditions. A quantitative and qualitative analysis of the SATS thermal performance has been conducted employing various solar air collector configurations under Scottish weather conditions. The pneumatic characteristics of the solar dryer including the dryer are determining for the analysis of the system performance. Because of the PV driven fan electrical characteristics, the SATS presents a unique operation regime in which air flow depends exclusively on solar radiation. Thus the SATS thermal performance has been successfully modelled as a function of irradiance. The study necessarily includes the effect of environmental factors such as wind and cloudiness in the transient regime. The potential of using a solar woodchip dryer has been assessed based on the results obtained from modelling the dryer and the SATS together. The feasibility and employability of using the solar dryer for drying woodchips is discussed considering the productivity, the energy savings, costs and integration.
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OJO, SAHEED OLALEKAN. "Thermo-visco-elastic modelling of photovoltaic laminates: Advanced shear-lag theory and model order reduction techniques." Doctoral thesis, Politecnico di Torino, 2016. http://hdl.handle.net/11583/2650003.
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During lamination, residual thermo-mechanical stresses are induced in the encapsulated solar cells composing photovoltaic (PV) modules. Depending on the material and geometrical configuration of the layers of the laminate, this residual stress field can be beneficial since it may lead to a compressive stress state in Silicon and therefore crack closure effects in the presence of cracks, with a recovery of electrical conductivity in cracked solar cells. It is therefore important to investigate the distribution of thermo-mechanical stresses within the PV laminate with a view to optimizing the coupling between the electrical response and elastic deformation in the operation of PV modules. A promising approach proposed in the present thesis regards the prediction of residual stresses in composite laminates by using a shear-lag theory to model the epoxy-vinil-acetate polymeric layers, accounting for their thermo-visco-elastic response. Moreover, it will be shown that thermomechanical formulations for stress analysis of a PV laminate lead to a system of higher order ordinary differential equations or partial differential equations in which the exact solutions may be impossible to be determined in closed form and hence numerical schemes become desirable. However, the computational cost associated with the implementation of the numerical scheme may be significantly expensive. Therefore, a method to reduce the computational complexity is expected to be very important. To this aim, Model Order Reduction (MOR) techniques are applied hierarchically, first to the thermal system of a PV module in service, and then extended to coupled thermo-mechanical problems. A combination of proper orthogonal decomposition (POD) and discrete empirical interpolation method (DEIM) with a modified formulation is proposed for the first-order thermal equations of photovoltaic system during service and a new coupled second-order Krylov based formulation is developed for model order reduction of the coupled thermo-mechanical model of the photovoltaic module. The results of these reduction schemes show a huge computational gain in the reduced system solutions and a high accuracy of the reduced system outputs.
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Mehranfar, Shayan. "Finite Element Modelling and On-Site Measurements for Roof Mounted Photovoltaic Solar Panels under High Wind Load." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31748.
Full textAbstract:
The application of dynamic wind load on photovoltaic (PV) solar systems mounted on
flat roofs influenced their structural behavior significantly. It is implied that when the PV solar system is exposed to extreme weather characteristics such as low temperatures, these might influence the load distribution along each layer of the solar panel, which is composed by multiple layers of different materials. Therefore, the high record of weather characteristics as one scenario in addition to the field experiment were designed to describe parametric structural behavior of PV solar system help to increase the precision of study. According to the mentioned procedures different parameters of weather characteristics measured with instrumentation at the site of PV panel installation at the University of Ottawa
where the low temperature equal to -24.3° C and wind speed of 11.8 recorded. The
mechanical and thermal properties of full-scale specimen and load application that computed based on weather record for every two minutes of January and February from northern side of specimen, introduced to FEM software SAP 2000. Moreover, the support structure and connection used to assemble real specimen considered in modeling with respect to average temperature equal to -7° C that caused to simulate 36 different cases to compare with simultaneous experiment designed to measured strain within same period. The second investigation involved instrumenting a full-scale PV solar panel specimen with 13 half-bridge strain gauges on both surfaces of the PV solar panel, which were used to measure strain values in longitudinal and transversal directions of solar panel and also on the
top and bottom edges of the same panel. According to an equivalent uniform Young’s modulus numerically determined for the five layers of the PV solar panel, and with respect to the Hook’s law, the stresses were found to be equal to 50 Mpa for strain gauges at the mid area of PV solar panel,. This value was used to calibrate boundary conditions of the FE model namely the Fix-Equal and the Pin-Equal conditions along the edges of the solar panel and along the mounting frame.
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Chong, Benjamin Vui Ping. "Modelling and controlling of integrated photovoltaic-module and converter systems for partial shading operation using artificial intelligence." Thesis, University of Leeds, 2010. http://etheses.whiterose.ac.uk/11321/.
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The thesis has three main themes: analysis and optimal design of Cuk DC-DC converters; integration of Cuk DC-DC converters with photovoltaic (PV) modules to improve operation during partial shading; and an artificial intelligence model for the PV module, permitting an accurate maximum power point (MPP) tracking in the integrated system. The major contribution of the thesis is the control of an integrated photovoltaic module and DC-DC converter configuration for obtaining maximum power generation under non-uniform solar illumination. In place of bypass diodes, the proposed scheme embeds bidirectional Cuk DC-DC converters within the serially connected PV modules. A novel control scheme for the converters has been developed to adjust their duty ratios, enabling all the PV modules to operate at the MPPs corresponding to individual lighting conditions. A detailed analysis of a step-down Cuk converter has been carried out leading to four transfer functions of the converter in two modes, namely variable input - constant output voltage, and variable output - constant input voltage. The response to switch duty ratio variation is shown to exhibit a non-minimum phase feature. A novel scheme for selecting the circuit components is developed using the criteria of suppressing input current and output voltage ripple percentages at a steady state, and minimising the time integral of squared transient response errors. The designed converter has been tested in simulation and in practice, and has been shown to exhibit improved responses in both operating modes. A Neuro-Fuzzy network has been applied in modelling the characteristics of a PV module. Particle-Swarm-Optimisation (PSO) has been employed for the first time as the training algorithm, with which the tuning speed has been improved. The resulting model has optimum compactness and interpretability and can predict the MPPs of individual PV modules in real time. Experimental data have confirmed its improved accuracy. The tuned Neuro-Fuzzy model has been applied to a practical PV power generation system for MPP control. The results have shown an average error of 1.35% compared with the maximum extractable power of the panel used. The errors obtained, on average, are also about four times less than those using the genetic-algorithm-based model proposed in a previous research. All the techniques have been incorporated in a complete simulation system consisting of three PV panels, one boost and two bidirectional Cuk DC-DC converters. This has been compared under the same weather conditions as the conventional approach using bypass diodes. The results have shown that the new system can generate 32% more power.
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Noori, Keian. "Energy-level alignment at organic and hybrid organic-inorganic photovoltaic interfaces." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:d1b2a4e9-a5d6-4843-b172-6d83dea8a6cb.
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Organic and hybrid organic-inorganic photovoltaic (PV) devices have the potential to provide low-cost, large scale renewable energy. Despite the tremendous progress that has been made in this field, device efficiencies remain low. This low efficiency can be partly attributed to the low open-circuit voltages (Voc) generated by organic and hybrid organic-inorganic PV devices. The Voc is critically determined by the energy-level alignment at the interface between the materials forming the device. In this thesis we use first-principles methods to explore the energy-level alignment at the interfaces between the conjugated polymer poly(3-hexylthiophene) (P3HT) and three electron acceptors, zinc oxide (ZnO), gallium arsenide (GaAs) and graphene. We find that Voc reported in the literature for ZnO/P3HT devices is significantly lower than the theoretical maximum and that the interfacial electrostatic dipole plays an important role in the physics underlying the charge transfer at the heterojunction. We note significant charge transfer from the polymer to the semiconductor at GaAs/P3HT interfaces, and use this result to help interpret experimental data. Our findings support the conclusion that charge transferred from P3HT to GaAs nanowires can passivate the surface defect states of the latter and, as a result, account for the observed decrease in photoluminescence lifetimes. Finally, we explore the energy-level alignment at the graphene/P3HT interface and find that Voc reported for experimental devices is in line with the theoretical maximum. The effect of functionalised graphene is also examined, leading to the suggestion that functionalisation might have important consequences for device optimisation.
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Yasin, Aysar Mahmoud Masoud. "Distributed Generation Systems Based on Hybrid Wind/Photovoltaic/Fuel Cell Structures." Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/995.
Full textAbstract:
The distributed generation (DG) today attracts a large interest due to an even increasing demand of energy and the growth of awareness about the impact of conventional energy sources on the environment.
Photovoltaic (PV) and wind power are two of the most promising renewable energy technologies. Fuel cell (FC) systems also show enormous potential in future DG applications, due to a fast technology development, high efficiency, environment friendliness and modularity. Hybrid systems encompassing wind, photovoltaic and FC generators are today revised as a viable solution to overcome the inner unreliability of renewable energy sources.
The modelling and control of a hybrid wind/PV/FC DG system is addressed in this dissertation. Dynamic models for the main system components, namely: wind and PV energy generators, fuel cell, electrolyser, power electronic interfaces, battery, hydrogen storage tank, gas compressor, are developed and verified by experimental tests and simulation studies.
Five different architectures of stand-alone hybrid power systems are considered, exploiting connections through DC and AC buses. Each configuration is managed through a specific control methodology. Based on suitable dynamic models, the five proposed stand-alone hybrid energy system configurations have been simulated using the MATLAB/Simulink/SimPowSysTM software environment.
A comparison among those configurations has been performed on the basis of purposely developed performance indexes. According to obtained results the high voltage DC bus (HVDC) configuration reaches the best score among the five configurations.
A Fuzzy logic based management of a stand-alone hybrid generator based on high voltage DC bus configuration has been developed to dynamically optimize the power flows among the different energy sources. The performances of the proposed strategy are evaluated by simulation in different operating conditions. The results confirm the effectiveness of the proposed strategy.
A further goal of the thesis has been the development of a probabilistic approach to size step-up transformers for grid-connected wind farms. This approach is mainly based on the evaluation of the Loss of Produced Power Probability index (LPPP); the costs of the wind farm equipments are also taken into consideration.
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Lodi, Chiara. "Modelling the energy dynamics of ventilated photovoltaic facades using stochastic differential equations in a monitored Test Reference Environment." Doctoral thesis, Universitat de Lleida, 2012. http://hdl.handle.net/10803/84167.
Full textAbstract:
L'objectiu general d'aquest treball és contribuir a l'avaluació de la transferència de l'energia en règim dinàmic de sistemes Fotovoltaics de doble pell Integrats en Edificis (EIFV) amb ventilació forçada sota condicions climàtiques exteriors reals.
Per tant, un dels objectius d'aquest treball de recerca va consistir a recol.lectar dades experimentals sota condicions externes reals amb el “Test Reference Environment” (TRE) al Parc Científic i Tecnològic Agroalimentari de Lleida (PCiTAL). Es va dur a terme una llarga campanya de mesures on es van realitzar diversos experiments, amb diferents inclinacions i règims de ventilació.
Un altre objectiu va ser estimar paràmetres físics desconeguts mitjançant l'ús de models d'identificació. Per aconseguir aquest objectiu, diversos models de caixa grisa estocàstics es van desenvolupar.
Finalment, a partir de l'experiència adquirida durant el treball experimental, d'anàlisi i de modelatge, s'ha proposat la definició d'un entorn de prova “Test Reference Environment” estandarditzat per a les aplicacions de EIFV de doble pell.El objetivo general de este trabajo es contribuir a la evaluación de la transferencia de la energía en régimen dinámico de sistemas de doble piel FotoVoltaicos Integrados en Edificios (EIFV) con ventilación forzada bajo condiciones climáticas exteriores reales. Por lo tanto, uno de los objetivos de este trabajo de investigación consistió en recolectar datos experimentales bajo condiciones externas reales con el “Test Reference Environment” (TRE) en el Parque Científico y Tecnológico Agroalimentario de Lleida (PCiTAL). Se llevó a cabo una larga campaña de medidas donde se realizaron varios experimentos, con diferentes inclinaciones y regímenes de ventilación. Otro objetivo fue estimar parámetros físicos desconocidos mediante el uso de modelos de identificación. Para lograr este objetivo, varios modelos de caja gris estocásticos se desarrollaron. Por último, a partir de la experiencia adquirida durante el trabajo experimental, de análisis y de modelación, se ha propuesto la definición de un entorno de prueba “Test Reference Environment” estandarizado para las aplicaciones de EIFV de doble piel.
The general aim of this work is to contribute to the energy dynamics assessment of mechanically ventilated double skin Building Integrated PhotoVoltaic (BIPV) systems under real outdoor weather conditions. Therefore, one of the objectives of this research work has consisted in collecting experimental data under real outdoor conditions in the Test Reference Environment (TRE) at the Lleida Agri-food Science and Technology Park (PCiTal). An extensive monitoring campaign has been carried out and several experiments, at different inclinations and ventilation regimes, have been performed. Another goal was to estimate unknown physical parameters by using identification models. To achieve this goal, several stochastic grey-box models have been developed. Finally, from the experience gained during the experimental, analysis and modelling work, the definition of a standardized set-up for a Test Reference Environment for double skin applications of BIPV has been proposed.
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Ramadan, Khaled Mohamed. "Modelling and Experimental Characterization of Photovoltaic/Thermal Systems for Cooling and Heating of Buildings in different climate conditions." Doctoral thesis, Universitat Rovira i Virgili, 2021. http://hdl.handle.net/10803/670914.
Full textAbstract:
La integración de sistemas de fotovoltaicos/térmicos (PV/T) y un eficiente aire acondicionado en los edificios permite el
suministro de calefacción, refrigeración y electricidad con una reducción de las emisiones de efecto invernadero. Las
configuraciones de integración de: a) sistemas fotovoltaicos (PV) con enfriadores eléctricos refrigerados por aire y
sistemas de bombas de calor aire-agua; b) sistemas fotovoltaicos/térmicos (PV/T) basados en aire con sistemas de
bomba de calor aire-agua; y c) Los sistemas fotovoltaicos/térmicos de baja concentración (LCPV/T) con enfriadores de
compresión y absorción tienen un gran potencial para aumentar la proporción de electricidad fotovoltaica in situ.
La flexibilidad de incorporar energía LCPV/T para la red bidireccional de baja temperatura en distritos urbanos reduce
las pérdidas térmicas y proporciona edificios de productores y consumidores (prosumidores). En comparación con la
configuración típica del enfriador de compresión integrado fotovoltaico, la configuración propuesta de LCPV/T junto
con los enfriadores de compresión y absorción reduce el período de recuperación en un 10-40% en el edificio de cajas
en El Cairo. Sustituir la conexión a la red de agua del campus por el uso de bomba de calor reversible reduce en un
15-30% el coste operativo de refrigeración y calefacción en el edificio de cajas en España.The integration of photovoltaic/thermal (PV/T) and efficient air conditioning systems into buildings allows the provision of heating, cooling and electricity with a reduction in greenhouse emissions. The integration configurations of: a) photovoltaic (PV) systems with air-cooled electric chillers and air-to-water heat pump (HP) systems; b) air-based PV/T systems with air-to-water HP systems; c) Low concentrated photovoltaic/thermal systems (LCPV/T) with compression and absorption chillers; and d) LCPV/T coupled with water-to-water HP have a great potential in boosting the share of onsite PV-electricity. The flexibility of incorporating LCPV/T energy for the bidirectional low temperature network in urban districts reduces thermal losses and provides producer and consumer (prosumer) buildings. In comparison to the typical configuration of PV integrated compression chiller, the proposed configuration of LCPV/T coupled with the compression and absorption chillers reduces the payback period by 10-40% in the case building in Cairo. Substituting the connection to the campus water network with the use of reversible
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Sahli, Mehdi. "Simulation and modelling of thermal and mechanical behaviour of silicon photovoltaic panels under nominal and real-time conditions." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAD036.
Full textAbstract:
Le travail présenté dans cette thèse porte sur le développement d’un modèle multi-physique numérique, destiné à étudier le comportement optique, électrique et thermique d’un module photovoltaïque. Le comportement optique a été évalué en utilisant des chaines de Markov. Le comportement électrique est obtenu pour les panneaux en Silicium à l’aide d’une méthode d’optimisation numérique. Le comportement thermique est développé en 1D sur l’épaisseur du module, et le modèle multi-physique a été faiblement couplé sous MATLAB. Le comportement sous des conditions nominales d’opération a été validé en utilisant les données déclarées par les constructeurs. Ce modèle a été utilisé pour effectuer une étude paramétrique sur l’effet des irradiances solaires en régime permanent. Le modèle a été validé pour des conditions d’utilisations réelles en comparant avec des mesures expérimentales de température et de puissance électrique. Une étude thermomécanique en 2D sous ABAQUS/CAE et se basant sur le modèle multi-physique a été effectué en conditions nominales d’opération, ainsi qu’en cycle de fatigue selon la norme 61215 pour prédire les contraintes qui sont imposées sur le panneau dans les deux cas mentionnés précédemmentThe work presented in this thesis deals with the development of a numerical multi-physics model, designed to study the optical, electrical and thermal behaviour of a photovoltaic module. The optical behaviour was evaluated using stochastic modelling based on Markov chains, whereas the electrical behaviour was drawn specifically for Silicon based photovoltaic panels using numerical optimization methods. The thermal behaviour was developed in 1D over the thickness of the module, and the multi-physics module was weakly coupled in MATLAB. The behaviour of commercial panels under nominal operation conditions was validated using data declared by the manufacturers. This model was used to perform a parametric study on the effect of solar irradiances in steady state. It was also validated for real use conditions by comparing it to experimental temperature and electrical power output. A thermomechanical study in 2D in ABAQUS/CAE based in the multi-physics model was carried out in nominal operating conditions, as well as in fatigue thermal cycling according to the IEC 61215 Standard to predict the stresses that are imposed on the panel
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Malm, Ulf. "Modelling and Degradation Characteristics of Thin-film CIGS Solar Cells." Doctoral thesis, Uppsala University, Solid State Electronics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9291.
Full textAbstract:
Thin-film solar cells based around the absorber material CuIn1-xGaxSe2 (CIGS) are studied with respect to their stability characteristics, and different ways of modelling device operation are investigated. Two ways of modelling spatial inhomogeneities are detailed, one fully numerical and one hybrid model. In the numerical model, thin-film solar cells with randomized parameter variations are simulated showing how the voltage decreases with increasing material inhomogeneities.
With the hybrid model, an analytical model for the p-n junction action is used as a boundary condition to a numerical model of the steady state electrical conduction in the front contact layers. This also allows for input of inhomogeneous material parameters, but on a macroscopic scale. The simpler approach, compared to the numerical model, enables simulations of complete cells. Effects of material inhomogeneities, shunt defects and grid geometry are simulated.
The stability of CIGS solar cells with varying absorber thickness, varying buffer layer material and CIGS from two different deposition systems are subjected to damp heat treatment. During this accelerated ageing test the cells are monitored using characterization methods including J-V, QE, C-V and J(V)T. The degradation studies show that the typical VOC decrease experienced by CIGS cells subjected to damp heat is most likely an effect in the bulk of the absorber material.
When cells encapsulated with EVA are subjected to the same damp heat treatment, the effect on the voltage is considerably reduced. In this situation the EVA is saturated with moisture, representing a worst case scenario for a module in operation. Consequently, real-life modules will not suffer extensively from the VOC degradation effect, common in unprotected CIGS devices.
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Odeh, Ibrahim Khalil. "Modelling, field data analysis and economics of photovoltaic water pumps and the prospects for integrating desalination using reverse osmosis." Thesis, University of Ulster, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419108.
Full text
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Mesbahi, Abdessamad. "Deterministic and Stochastic Economic Modeling of Hybrid Power Supply System with Photovoltaic Generators." Master's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/42555.
Full textAbstract:
Relevance of research. Due to the rapid deployment of the non-dispatchable (intermittent) generation sources in the smart grid, such as integration of the photovoltaic power plants and wind turbines in the distribution systems; this caused a problem of the uncertainty increase of simulation results for decision-making for power supply systems, these uncertainties of power systems are getting more and more notice. At the same time, the classical power systems models cannot give accurate simulation results. Wherein; it became necessary to define new models to represent the specific parameters of power system. wherein; this research reveals to the benefits of using probabilistic mathematical approaches to define and calculate the specific economic parameters, as well as the technical parameters for power supply system with the integration renewable energy generators, which are characterising by randomness and uncertainty due to the high penetration to the renewables. Monte Carlo Method, and Point Estimation Method are used to handle the uncertainties of renewable energy resources. The standard functions to represent the stochastic parameters of the model are analyzed with the use of three-point estimation technique for the distribution functions of their probable values. A synthetic skewed probability density function was analytically constructed basing on the standard normal distribution, which is suitable for analytic representation of the predicted and/or statistical random sampling of the uncertain model parameters of energy system with renewables, and analytical expressions were obtained to compute the moments of proposed synthetic probability function.
Relationship of work with scientific programs, plans, themes. is to demonstrate the possibility of describing the input parameters of the simulation Deterministic and Stochastic Modeling by probability Density Functions by the use of three-point approximation techniques and to obtain analytical expressions for the characteristics of such distributions, suitable for non-iterative (as opposed to Monte Carlo Method) probabilistic method applications, namely the Point Estimation Method.
Purpose and tasks of the research. Increasing the simulation accuracy results for estimation economic and technical parameters characterising photovoltaic power plant based on based on the life cycle model; as well as development of different algorithms based on deterministic and stochastic modeling of power system with non-dispatchable sources and minimize the computation time.
Object of research. Processes of determining the estimated technical and economic parameters characterising a photovoltaic power plant located in Ukraine basing on stochastic modeling.
Subject of research. Use of the Monte Carlo Method and Point Estimation Method to estimate the various economic and technical information characteristic of alternative power plants in order to obtain accurate simulation results.
Practical value of the results. Practical techniques of the three-point approximation are used to construct the probability density function of the model uncertain (stochastic) parameter, which dominantly influences the modeling result: an event occurrence probability, the result attainability, whatsoever. This technique is an effective tool for the practical evaluating of an uncertain value of a technological or economic factor of material and/or economic object, and widely used for overall Levelized Energy Cost (LCOE – LEC) which is directly or indirectly engaged into analytic representation of the power systel model. Usually, the model of a kind is designed to solve technical and/or economic problem by means of Deterministic and Stochastic Modeling.
Scientific novelty of the obtained results is the development of algorithms and mathematical solutions using a probabilistic approach basing Point Estimation Method instead of Monte Carlo Melthod to obtain more accurate estimation simulation results, as well as to obtain computational results in less time for useful decision-making in alternative power plant projects.
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Schön, Gustav. "NUMERICAL MODELLING OF A NOVEL PVT COLLECTOR AT CELL RESOLUTION." Thesis, KTH, Energiteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-212731.
Full textAbstract:
Solar photovoltaic-thermal (PVT) modules produce heat and power via a heat exchanger attached to the rear of the PV cells. The novel PVT collector in this study is previously untested and therefore its behaviour and thermo-electric performance due to fluid channel configuration and in various climate and operating conditions are unknown. Moreover, the working fluid flowing through the heat exchanger cause a temperature gradient across the module such that a cell near the inlet and a cell near the outlet may have significant temperature differences. PV cells are sensitive to temperature; however the most common way to simulate power output from a PVT is to use the average temperature and ignore the gradient. In this study, a single diode PV model is incorporated into a commercial thermal solver to co-simulate the thermal and electrical output of a novel PVT module design with cell level resolution. The PVT system is modelled in steady state under various wind speeds, inlet temperatures, ambient temperatures, flow rates, irradiation, convection coefficients from coolant and back of the module and two different fluid channel configurations. The results show that of the controllable variables, the inlet temperature has the highest influence of the total power output and that a parallel flow of the fluid channel configuration is preferable. The difference between the cell resolution and the module resolution simulations do not motivate the use of a higher resolution numerical simulation.En kombinerad solcellspanel och solvärmefångare (PVT) producerar värme och elenergi på samma yta genom att en värmeväxlare upptar värmen från baksidan av solcellspanelen. Den PVT som berörs i denna studien är nyutvecklad och har aldrig tidigare testats, vilket medför att data för hur den beter sig samt dess termo-elektiska prestanda saknas för olika driftförhållanden samt flödeskonfigurationer. Vidare ger mediet som flödar genom värmeväxlaren upphov till en temperaturgradient, vilken kan innebära en påtaglig skillnad i temperatur mellan solcellerna i solcellspanelen vid mediets in- respektive utlopp. Trots solcellers temperaturkänslighet, så sker simulering i allmänhet med avseende på panelens medeltemperatur istället för att hänsyn tas till denna temperaturgradient. I den här studien implementeras en så kallad ”single diode”-modell i en kommersiell numerisk mjukvara termiska beräkningar för att samsimulera termiskt och elektriskt effektuttag ur den nyutvecklade PVT-designen. Designen modelleras statiskt under givna variationer av vindhastighet, inloppstemperatur, omgivande temperatur, flödeshastighet, solinstrålning och konvektionskoefficienter för mediet samt baksidan av modulen. Resultaten visar att kontrollerbara variabler som inloppstemperatur har högst inverkan på den totala effekten samt att en parallell flödeskonfiguration lämpar sig bäst. Studien visar också att skillnaden mellan simulering på cellnivå och modulnivå inte motiverar en numerisk beräkningsmetod med upplösning satt till solcellsnivå.
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Mockus, Modestas. "Autonominės saulės energijos sistemos modeliavimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120202_135157-77748.
Full textAbstract:
Energetikos sistemos decentralizacija yra neišvengiamai susijusi su šiuolaikinės energetikos sistemos perėjimu prie tvarios ir ilgalaikės alternatyvos – atsinaujinantys energijos šaltiniai. Viena didžiausių perspektyvų – saulės energetika. Šiame darbe atlikta literatūros analizė apie fotovoltines sistemas ir jų komponentus. Remiantis vidutinio Lietuvos gyventojo elektros vartojimo įpročiais, atiktas modeliavimas sistemos, kuri tenkintų vidutinius poreikius. Optimizuojant elektros energijos vartojimą ir sistemos komponentus stebėta kaip tai veikia energijos suvartojimą, perteklinės energijos efektyvesnį panaudojimą, akumuliatorių darbo režimą. Įvertintas sistemos veikimas mažiausio ir didžiausio saulės spinduliuotės lygio Lietuvoje sąlygomis.Decentralization of today‘s energy system is inevitability related to conversion to sustainable power system. Solar energy has the most potential to partially replace finite energy sources used today. A research on solar power systems and main components of the autonomous system was made in this paper. Autonomous photovoltaic system modelling was conducted. System size was chosen with reference to middle class user electric power consumption habbits in Lithuania. Consumption optimization and system load optimization were done and effects on consuption rate, excess electricity output and operating mode of batteries were observed and analysed. Optimized system‘s operation during the lowest and highest solar radiation conditions in Lithuania were evaluated.
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Trapani, Kim. "FLEXIBLE FLOATING THIN FILM PHOTOVOLTAIC (PV) ARRAY CONCEPT FOR MARINE AND LACUSTRINE ENVIRONMENTS." Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2199.
Full textAbstract:
The focus of the research is on the development of the concept of floating flexible thin film arrays for renewable electricity generation, in marine and lacustrine application areas. This research was motivated by reliability issues from wave energy converters which are prone to large loads due to the environment which they are exposed in; a flexible system would not need to withstand these loads but simply yield to them. The solid state power take off is an advantage of photovoltaic (PV) technology which removes failure risks associated with mechanical machinery, and also potential environmental hazards such as hydraulic oil spillage. The novelty of this technology requires some development before it could even be considered feasible for large scale installation. Techno-economics are a big issue in electricity developments and need to be scoped in order to ensure that they would be cost-competitive in the market and with other technologies.
Other more technical issues relate to the change in expected electrical yield due to the modulation of the PV array according to the waves and the electrical performance of the PVs when in wet conditions. Results from numerical modelling of the modulating arrays show that there is not expected variation in electrical yield at central latitudes (slightly positive), although at higher latitudes there could be considerable depreciation. With regards to the electrical performance a notable improvement was measured due to the cooling effect, slight decrease in performance was also estimated due to water absorption (of ~ 1.4%) within the panels. Overall results from both economic and technical analysis show the feasibility of the concept and that it is a possibility for future commercialisation.
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Tatsiankou, Viktar. "Instrumentation Development for Site-Specific Prediction of Spectral Effects on Concentrated Photovoltaic System Performance." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31222.
Full textAbstract:
The description of a novel device to measure the spectral direct normal irradiance is presented. The solar spectral irradiance meter (SSIM) was designed at the University of Ottawa
as a cost-effective alternative to a prohibitively expensive field spectroradiometer (FSR). The latter measures highly-varying and location-dependent solar spectrum, which is essential for accurate characterization of a concentrating photovoltaic system’s performance. The SSIM measures solar spectral irradiance in several narrow wavelength bands with a combination of photodiodes with integrated interference filters. This device performs spectral measurements at a fraction of the cost of a FSR, but additional post-processing is required to deduce the
solar spectrum. The model was developed to take the SSIM’s inputs and reconstruct the
solar spectrum in 280–4000 nm range. It resolves major atmospheric processes, such as air mass changes, Rayleigh scattering, aerosol extinction, ozone and water vapour absorptions.
The SSIM was installed at the University of Ottawa’s CPV testing facility in September,
2013. The device gathered six months of data from October, 2013 to March, 2014.
The mean difference between the SSIM and the Eppley pyrheliometer was within ±1.5%
for cloudless periods in October, 2013. However, interference filter degradation and condensation negatively affected the performance of the SSIM. Future design changes will improve the longterm reliability of the next generation SSIMs.
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Sultani, Jasim Farhood. "Modelling, design and implementation of D-Q control in single-phase grid-connected inverters for photovoltaic systems used in domestic dwellings." Thesis, De Montfort University, 2013. http://hdl.handle.net/2086/9631.
Full textAbstract:
This thesis focuses on the single-phase voltage-source inverter for use in photovoltaic (PV) electricity generating systems in both stand-alone and grid-tied applications. In many cases, developments in single-phase PV systems have followed developments in three-phase systems. Time-variant systems are more difficult to control than time-invariant systems. Nevertheless, by using suitable transformation techniques, time-variant systems can often be modelled as time-invariant systems. After the transformation, the control signals that are usually time-variant (often varying sinusoidally in time) become time-invariant at the fundamental frequency, and are hence much easier to deal with. With this approach, synchronous rotating frame control techniques have been previously proposed for high performance three-phase inverter applications. The transformation theory cannot be applied directly in single-phase systems without modification, and the d-q components would not be time-invariant in situations where harmonics, resonances or unbalance is present. Single-phase inverter controller designs based on the use of a synchronous rotating reference frame have been proposed, but such designs do not always perform as well as expected. This thesis aims to improve single-phase voltage-source inverters. The main objective is to address, in terms of cost, efficiency, power management and power quality, the problems found with single-phase designs based on a synchronous rotating frame single-phase inverter controller. Consequently, this thesis focuses on a novel controller approach in order to obtain a more reliable and flexible single-phase inverter. As the first step, this thesis investigates the single-phase inverter switching gate-drive algorithms and develops a form of space-vector pulse-width-modulation (SVPWM) in order to reduce total harmonic distortion. The results of the new SVPWM algorithm demonstrate its superior performance when compared with sinusoidal pulse-width-modulation (SPWM) which is often used with single-phase inverters. The second step, which is further reviewed and presented in this thesis, is the modelling of the single-phase inverter control based on the synchronous rotating frame. A mathematical analysis is conducted to determine the mechanism of the coupling that exists between the voltage phase and amplitude terms, and a new transformation strategy is proposed based on using the voltage phase as a reference at the Park transformation stages, and the current phase as a reference for the current at the transformation stages. The line-frequency components of the feedback signals are transformed to time-invariant components, thus eliminating the ripple and reducing the computational burden associated with the controller stage. Consequently, the inverter feedback controller stage is designed so that the coupling terms are decoupled within the controller itself. The effectiveness of the techniques proposed in this thesis are demonstrated by simulation using the MATLAB/SIMULINK environment. The proposed technique was also investigated through a practical implementation of the control system using a Digital Signal Processor (DSP) and a single-phase inverter. This practical system was tested up to 1 kW only (limited by the available inverter hardware). Nevertheless, the correlation between the simulation and the practical results is high and this gives confidence that the developed mechanism will allow the 2.5kW goal to be achieved. Practical test cases illustrate the effectiveness of the models. In addition, the comparisons between experimental and simulation results permit the system's behaviour and performance to be accurately evaluated. With the development of the new controller, small-scale single-phase renewable energy systems will become more useful in the field of power quality management through their ability to separately control the phase and amplitude of the output voltage. Consequently, incorporation of this type of generator within the national electrical distribution network, as distributed generators (DG) at low-voltage level, can assist with power quality management at the consumer side of the grid. In addition, such a generator can also operate in stand-alone mode if the grid becomes unavailable. The third step in this thesis investigates small-scale single-phase renewable energy systems operating as decentralized distributed generators within a local network. This operation is achieved by controlling the inverter side using the quantities measured at the common coupling point between the grid and the inverter, without requiring other extensive communications. Thus, the small-scale single-phase renewable energy distributed generator systems will contain only a local controller at each installation.
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Kozlowski, Fryderyk. "Numerical simulation and optimisation of organic light emitting diodes and photovoltaic cells." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1134592504212-65990.
Full textAbstract:
A numerical model and results for the quantitative simulation of multilayer organic light emitting diode (OLED) and organic solar cell (OSC) are presented. In the model, effects like bipolar charge carrier drift and diffusion with field-dependent mobilities, trapping, dopants, indirect and direct bimolecular recombination, singlet Frenkel exciton diffusion, normal decay and quenching effects are taken into account. For an adequate description of multilayer devices with energetic barriers at interfaces between two adjacent organic layers, thermally assisted charge carrier hopping through the interface, interface recombination, and formation of interface charge transfer (CT) states have been introduced in the model. For the simulation of OSC, the generation of carrier pairs in the mixed layer or at the interface is additionally implemented. The light absorption profile is calculated from optical simulations and used as an input for the electrical simulation. The model is based on three elements: the Poisson equation, the rate equations for charge carriers and the rate equations for singlet Frenkel excitons. These equations are simultaeously solved by spatial and temporal discretisation using the appropriate boundary conditions and electrical parameters. The solution is found when a steady state is reached, as indicated by a constant value of current density. The simulation provides a detailed look into the distribution of electric field and concentration of free and trapped carriers at a particular applied voltage. For organic light emitting diodes, the numerical model helps to analyze the problems of different structures and provides deeper insight into the relevant physical mechanisms involved in device operation. Moreover, it is possible to identify technological problems for certain sets of devices. For instance, we could show that ? in contrast to literature reports - the contact between Alq3 and LiF/Al did not show ohmic behaviour for the series of devices. The role of an additional organic blocking layer between HTL and EML was presented. The explanation for the higher creation efficiency for singlet excitons in the three-layer structure is found in the separation of free holes and electrons accumulating close to the internal interface 1-Naphdata/Alq3. The numerical calculation has demonstrated the importance of controlled doping of the organic materials, which is a way to obtain efficient light emitting diodes with low operating voltage. The experimental results has been reproduced by numerical simulation for a series of OLEDs with different thicknesses of the hole transport layer and emitting layer and for doped emitting layers. The advantages and drawbacks of solar cells based on flat heterojunctions and bulk heterojunctions are analyzed. From the simulations, it can be understood why bulk-heterojunctions typically yield higher photocurrents while flat heterojunctions typically feature higher fill factors. In p-i-n ?structures, p and n are doped wide gap materials and i is a photoactive donor-acceptor blend layer using, e.g,. zinc phthalocyanine as a donor and C60 as an acceptor component. It is found that by introducing trap states, the simulation is able to reproduce the linear dependence of short circuit currents on the light intensity. The apparent light-induced shunt resistance often observed in organic solar cells can also be explained by losses due to trapping and indirect recombination of photogenerated carriers, which we consider a crucial point of our work. However, these two effects, the linear scaling of the photocurrent with light intensity and the apparent photoshunt, could also be reproduced when field-dependent geminate recombination is assumed to play a dominant role. First results that show a temperature independent short circuit photocurrent favour the model based on trap-mediated indirect recombination.