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Modélisation dynamique et régulation des centrales solaires thermodynamiques linéaires à génération directe de vapeur / Dynamic modeling and control of line-focus concentrated solar plants using direct steam generationAurousseau, Antoine 27 April 2016 (has links)
Les Centrales Solaires Thermodynamiques à génération directe de vapeur utilisent la concentration optique du rayonnement solaire direct pour produire de la vapeur d'eau à haute pression et haute température. La vapeur d'eau est ensuite utilisée directement comme fluide de travail d'un cycle thermodynamique type Rankine, pour la propulsion d'un couple turbine-génératrice et assurer ainsi une production électrique. La conjonction de la variabilité naturelle de l'ensoleillement, qu'elle soit lente et déterministe (cycle jour/nuit, cycle saisonnier, dégradation des performances optiques), ou rapide et non déterministe (passages nuageux), et de la présence d'un écoulement diphasique eau/vapeur dans les tubes horizontaux, provoque un comportement fortement dynamique du système de génération de vapeur. Par ailleurs, les turbines à vapeur étant très sensibles aux fluctuations de la température d'admission de vapeur, il convient donc de réguler le plus efficacement possible la production de vapeur. Les temps de séjour de fluide dans les champs solaires linéaires pouvant être relativement longs, les stratégies de contrôle conventionnelles se révèlent moins adaptées et peu efficaces. L'objectif de ce travail est d'étudier, par la réalisation de modèles et de leur utilisation en simulation, le fonctionnement dynamique du système de génération de vapeur. Des modèles dynamiques de centrales linéaires de Fresnel et cylindro-parabolique sont réalisés, et des données expérimentales issues d'un prototype cylindro-parabolique sont utilisées pour la validation. Les modèles permettent ensuite l'étude de stratégies de régulation, permettant un contrôle de la vapeur sortant du champ solaire soumis à des transitoires. L'étude de l'utilisation de méthodes de prédiction de l'ensoleillement direct à court terme est abordée à la fin de ce travail, afin d'évaluer la possibilité d'intégrer ces méthodes dans les stratégies de régulation. / Direct steam generation concentrated solar power plants use the optical concentration of solar direct irradiation to generate high pressure and high temperature steam in the absorber tubes. Steam is used as the working fluid of a Rankine-type thermodynamic cycle for the propelling of a steam turbine and an electric generator. The conjunction of the natural transient condition of solar irradiation and the presence of a two-phase flow inside the absorber tubes leads to a strong dynamic behavior of the steam generation system. Moreover, steam turbines being very sensitive to inlet temperature transients, the control of steam generation has to be achieved with the best possible efficiency. Because of the large time constants of the flow in the solar field (among other reasons), basic control strategies are poorly efficient and not well suited. The aim of this thesis work is the study, through modeling and simulation, of the dynamic behavior of the steam generation system. Dynamic modeling of linear Fresnel and parabolic-trough solar plants is carried out, and experimental data from a parabolic-trough prototype are used for validation. The models are used for the study of advanced control strategies, for a better control of steam conditions at the solar field outlet, under irradiation transients. Short-term irradiation prediction methods are evaluated for a use in the control strategies.
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Performance Calculations and Optimization of a Fresnel Direct Steam Generation CSP Plant with Heat StorageSchlaifer, Perrine January 2013 (has links)
This master thesis deals with the performance calculations of a 9MW linear Fresnel CSP plant withdirect steam generation built by the Solar Division of the CNIM Company. The aim was to calculate theannual electricity production taking into account the weather conditions as well as some steam storage.At first, a steam accumulator model was developed with Excel, in order to estimate the pressureevolution in the tanks during the charging, storage and discharging processes. The data obtained withthis model was then integrated to the thermodynamic cycle model, programmed with Excel, whichcalculated the electrical power production knowing the thermal power available in the solar field. Theelectricity production calculations were made every 600 seconds during one year.To improve the results accuracy, the influence of the plant location slope was estimated, calculating theequivalent azimuth and elevation angles in a new spherical coordinates system. For an average slope of4.21° at the plant location, the annual thermal energy gain is 14.4% (with a gain up to 60% duringwinter days) and the annual electricity production is increased by 12.59%. The influence of frost on themirrors during cold and humid nights was also estimated with a simple model of the energy needed toheat up a constant layer of ice. Depending on the assumptions, the electricity production losses werebetween 1.27 and 2.84% of annual electricity production. The losses due to plant shutdowns set by theelectrical network manager RTE during the snowmelt months were also estimated. The annualelectricity production could decrease by 8.02 to 11.57 % because of the load management, dependingon the days during which the plant is shutdown.Finally, an economic optimisation was led with prices estimated by CNIM, which gave an optimal solarfield design with 31 lines and 5 steam accumulators. The payback time would then be 9.887 years.
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Techno-economic Analysis and Market Potential Study of Solar Heat in Industrial Processes : A Fresnel Direct Steam Generation case studyde Santos López, Guillermo January 2021 (has links)
The industrial sector not only has a big contribution to global emissions but also a low share of renewable energy for heat demand. Knowing that most of the energy consumption in industry is heat and that half of it is at medium-low temperature (below 400 ºC), it is a great market for the integration of solar thermal technologies. Following the criteria of high heat demand and low-temperature requirements, five promising industrial sectors and their processes have been analysed: food and beverage, paper and pulp, chemical, textile and mining. Steam generation at supply level has been considered one of the most promising systems considering its integration advantages and the potential of direct steam generation plants. The market potential study has been geographically determined performing an MCA; countries all over the world have been assessed considering their heat consumption in the promising sectors and other conditions that enhance the SHIP feasibility such as solar radiation levels, favourable energy policies, previous experience in SHIP plants, ease of doing business, etc. The price of natural gas has been also considered after selecting Europe as a suitable market. The potential heat demand that this technology could cover has been estimated considering limitations as the competitiveness with other renewable heat sources, the expected heat recovery potential for some sectors, the solar fraction of the region and roof space of the factories. The results show that the five countries with bigger potential are Germany, France, Netherlands, Italy, and Spain, while the sectors with the most suitable market are food and beverage, and chemical. A case study has been selected based on the previous conclusions: a Fresnel direct steam generation plant in Sevilla (Spain) characterized thanks to the data provided by the company Solatom. The plant has been modelled using the software TRNSYS, taking special consideration in the Fresnel performance, the dynamic steam drum behaviour and its influence on the start-up time of the plant. The results achieved through the techno-economic analysis show that parameters such as solar radiation, conventional fuel prices and EU ETS prices have a major impact on the economic indicators. A sensitivity analysis shows that locations with radiation levels above 1750 kWh/m2 have positive values for NPV, and above 2250 kWh/m2 the cost of generating solar heating (LCOH) is under European natural gas prices. In addition to this, fuel prices above 50 €/MWh, which are common for SMEs, results in payback periods under 10 years. Future trends depict favourable scenarios as current European policies are causing a rapid growth of the ETS. Therefore, solar heat in industrial processes can be a feasible alternative, or work as a complement, to conventional systems. Its deployment is driven by supportive policies, high radiation levels, costly fuels prices (such as the ones for SMEs) and the necessity of reducing GHG emissions and decrease the independence on fossil energies. / Industrisektorn har inte bara ett stort bidrag till globala utsläpp utan också en låg andel förnybar energi för värmebehov. Att veta att det mesta av energiförbrukningen i industrin är värme och att hälften av den är vid medelhög låg temperatur (under 400ºC), är det en fantastisk marknad för integration av solvärmeteknik. Enligt kriterierna för högt värmebehov och lågtemperaturkrav har fem lovande industrisektorer och deras processer analyserats: mat och dryck, papper och massa, kemikalier, textil och gruvdrift. Ånggenerering på leveransnivå har ansetts vara ett av de mest lovande systemen med tanke på dess integrationsfördelar och potentialen hos direkta ånggenereringsanläggningar. Marknadspotentialstudien har fastställts geografiskt med en MCA; länder över hela världen har bedömts med tanke på deras värmeförbrukning i de lovande sektorerna och andra förhållanden som förbättrar SHIP-genomförbarheten, såsom solstrålningsnivåer, gynnsam energipolitik, tidigare erfarenhet av SHIP-anläggningar, lätt att göra affärer etc. Priset på naturgas har också övervägs efter valet av Europa som en lämplig marknad. Det potentiella värmebehovet som denna teknik kan täcka har uppskattats med tanke på begränsningar som konkurrenskraft med andra förnybara värmekällor, den förväntade värmeåtervinningspotentialen för vissa sektorer, solfraktionen i regionen och fabrikernas takutrymme. Resultaten visar att de fem länderna med större potential är Tyskland, Frankrike, Nederländerna, Italien och Spanien, medan de sektorer som har den mest lämpliga marknaden är mat och dryck samt kemikalier. En fallstudie har valts utifrån de tidigare slutsatserna: en Fresnel-ångproduktionsanläggning i Sevilla (Spanien) som kännetecknas av uppgifterna från företaget. Anläggningen har modellerats med hjälp av programvaran TRNSYS, med särskild hänsyn till Fresnel-prestanda, det dynamiska ångtrummans beteende och dess inflytande på anläggningens starttid. De resultat som uppnåtts genom den tekno-ekonomiska analysen visar att parametrar som solstrålning, konventionella bränslepriser och EU: s ETS-priser har stor inverkan på de ekonomiska indikatorerna. En känslighetsanalys visar att platser med strålningsvärden över 1750 kWh/m2 har positiva värden för NPV och över 2250 kWh/m2 är kostnaden för att generera solvärme (LCOH) under europeiska naturgaspriser. Utöver detta leder bränslepriser över 50 €/MWh, som är vanliga för små och medelstora företag, till återbetalningsperioder under tio år. Framtida trender visar gynnsamma scenarier eftersom europeisk politik orsakar en snabb tillväxt på ETS. Därför kan solvärme i industriella processer vara ett genomförbart alternativ eller fungera som ett komplement till konventionella system. Dess utplacering drivs av stödjande politik, höga strålningsnivåer, dyra bränslepriser (som de för små och medelstora företag) och behovet av att minska växthusgasutsläppen och minska självständigheten för fossila energier.
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Carbon – based nanofluids and hybrid natural polymers for enhanced solar-driven evaporation of water: synthesis and characterizationMarchetti, Francesca 05 May 2020 (has links)
The scarcity of freshwater is becoming a global challenge worldwide due to limited resources availability and increasing demand both for manufacturing and household use. For this reason, there is an important need to develop efficient, economic and sustainable desalination technologies able to take advantage of unconventional sources of water (seawater, brackish groundwater and wastewater) in order to produce freshwater.
Sun is considered as the most promising abundant renewable (and free) energy source that can be employed in steam and vapor generation processes, which has a great importance in many applications such as: water desalination, domestic water heating, and power generation.
This doctoral dissertation presents a study on the efficiency of different carbon based systems - nanofluids and hybrid natural composites - for the improvement of direct-solar evaporation systems, for the production of freshwater. The two main goals of this work consist of: (i) the synthesis and characterization of stable carbon-based nanofluids in water and of re-usable, economical and ecological hybrid composite materials, and (ii) the comparison of such carbon-based systems applied to water evaporation, understanding mechanisms, advantages and limitations.
Carbon based materials (carbon black, graphene and multi-walled carbon nanotubes) were chosen because of their high sunlight absorption ability, unique thermal properties, as well as low cost and abundant availability. However, the hydrophobic character of such materials makes necessary to find efficient strategies to overcome this problem when dealing with water.
In this work, the suspension stability of graphene-based nanofluids in water - a key parameter for the application of nanofluids in any field - was effectively improved by combining physical (by RF Sputtering coating) or chemical (by NaClO-NaBr solution) graphene surface modification treatments, and the use of common additives (Triton X-114, SDBS and gum arabic) showing different stabilization mechanisms. The best strategy to obtain long-time graphene suspension stability in water (both deionized water and saline solution with 3.5 wt% NaCl) turned out to be the combination of the easy chemical treatment with the electro-steric stabilization effect of gum arabic.
In addition to nanofluids, a re-usable devices based on gum arabic cross-linked gelatin hydrogel were synthesized and characterized. Hydrophobic carbon-based materials were easily and uniformly embedded into the porous hydrogel matrix, thanks to the amphiphilic character of both gelatin and gum arabic. The effect of carbon-nanoparticles nature, morphology and concentration on the measured effective thermal conductivity of the composite material was studied and the thermal conductivity of the nanoparticles was evaluated applying several models based on the effective medium approach. The values obtained for the nanoparticles were far from the tabulated thermal conductivity values because of the combination of the composite features (such as nanoparticles concentration, Kapitza resistance) and the particles characteristics (such as aspect ratio, crystalline structure).
The performance of carbon-based nanofluids and hybrid hydrogels on direct-solar evaporation of water was tested and compared to that of carbon-wood bilayer composite (which presents both hydrophilic character and natural channels for water transportation) under solar simulator. The effect of surface temperature, light-to-heat conversion efficiency of carbon-based materials, heat losses, water transport through a porous medium and suspension stability (in the case of nanofluids) were investigated in order to understand the advantages and limitations of such systems.
All the tested systems were able to improve water evaporation rate and evaporation efficiency up to 70% and 82% under 1 sun and 2 suns respectively using a small amount of nanoparticles: the same amount of particles dispersed in nanofluid (0.01 wt%) was embedded into hydrogels or deposited onto wood. The high sunlight absorption ability of carbon-based nanoparticles appeared as a dominant parameter for the improvement of water evaporation rate. In fact, enhanced light absorption was directly related to a high photothermal conversion efficiency, which caused an improvement in the surface temperature, leading to a consequent enhancement in evaporation rate. It has been found that an adequate supply of water to the evaporation surface represents a fundamental parameter as well considering floating systems.
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Études expérimentales et numériques d'un micro-cogénérateur solaire : intégration à un bâtiment résidentiel / Experimental and numerical studies of a solar micro-cogenerator : integration into a residential buidlingMartinez, Simon 06 December 2018 (has links)
Ces travaux consistent en l’étude expérimentale et numérique des performances énergétiques d’un prototype de micro-cogénération solaire. L’installation, située sur le campus de l’Université de la Rochelle, fonctionne grâce au couplage d’un champ de capteur solaire cylindro-parabolique de 46,5 m² avec un moteur à vapeur à piston non lubrifié fonctionnant selon le cycle thermodynamique de Hirn. Le système de suivi solaire s’effectue selon deux axes et l’eau est directement évaporée au sein de l’absorbeur des capteurs cylindro-paraboliques. La génération d’électricité est assurée par une génératrice et la récupération des chaleurs fatales doit permettre d’assurer les besoins en chauffage et eau chaude sanitaire d’un bâtiment. La première partie de ces travaux présente les essais réalisés. L’objectif est de réaliser des essais complémentaires pour caractériser le concentrateur solaire, d’étudier les conditions de surchauffe de la vapeur, ainsi que le fonctionnement de l’installation complète en hiver. Ce travail a permis le développement de modèles pour le capteur cylindro-paraboliques, les essais en régime surchauffé ont montré la nécessité d’un appoint pour le fonctionnement d’une telle installation tandis que les essais avec moteur présentent des productions compatibles avec les consommations en électricité et chaleur d’un bâtiment résidentiel. La seconde partie concerne la modélisation des éléments constituant le micro-cogénérateur ainsi que l’intégration de cette installation au bâtiment à l’aide d’un logiciel de simulation thermique dynamique (TRNSYS©). Cette étude propose deux options d’intégration selon le positionnement de l’appoint de chaleur. Pour les deux configurations, des bilans hebdomadaires et annuels sont présentés permettant de discuter les avantages/inconvénients de chaque disposition. Il apparaît que le positionnement de l’appoint sur le circuit primaire permet de piloter la production électrique. L’ajout de l’appoint sur la distribution semble plus facilement réalisable mais empêche le contrôle de la production électrique. / This work consists of the experimental and numerical study of the energy performance of a prototype of solar micro-cogeneration. The facility, located on the campus of the University of La Rochelle, operates by coupling a 46.5 m² parabolic trough solar collector field with an oil-free piston steam engine operating according to the Hirn thermodynamic cycle. The solar tracking system is carried out in two axes and the water is evaporated directly into the absorber of the parabolic trough collectors. Electricity generation is provided by a generator and the recovery of fatal heat must make it possible to meet the heating and domestic hot water needs of a building. The first part of this work presents the tests performed. The objective is to carry out additional tests to characterize the solar concentrator, to study the conditions of steam overheating, as well as the operation of the complete installation in winter. This work has allowed the development of models for the parabolic trough sensor, the tests in overheated mode have shown the need for an extra charge for the operation of such an installation while the tests with motor present productions compatible with the electricity and heat consumption of a residential building. The second part concerns the modelling of the elements constituting the micro-cogenerator as well as the integration of this installation into the building using dynamic thermal simulation software (TRNSYS©). This study proposes two integration options depending on the positioning of the auxiliary heater. For both configurations, weekly and annual reviews are presented to discuss the advantages/disadvantages of each provision. It appears that the positioning of the auxiliary on the primary circuit makes it possible to control the electrical production. The addition of back-up boiler on the distribution seems more easily achievable but prevents the control of power generation.
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Étude expérimentale d'une installation de micro-cogénération solaire couplant un concentrateur cylindro-parabolique et un moteur à cycle de Hirn / Experimental study of a micro combined solar heat and power unit composed of a solar parabolic trough collector coupled to a Hirn cycle engineBouvier, Jean-Louis 02 December 2014 (has links)
L’objectif de cette thèse est d’étudier expérimentalement les performances énergétiques d'une installation de micro-cogénération solaire. Le prototype réalisé est constitué d'un concentrateur cylindro-parabolique associé à un moteur à vapeur fonctionnant suivant un cycle de Hirn (Rankine avec surchauffe). Les originalités de ce projet sont l’utilisation de l’énergie solaire, renouvelable et inépuisable mais intermittente, la génération directe de vapeur au sein d'un concentrateur de taille réduite (46,5 m²), le système de suivi solaire sur deux axes et le couplage à un moteur à piston non lubrifié. La première partie de l'étude porte sur le concentrateur seul. Son fonctionnement est étudié sur deux journées types (ensoleillée et nuageuse) et son rendement thermique est évalué. La dynamique du système est également abordée notamment par l'étude de sa réponse à des perturbations. Une régulation de type boucle ouverte a été mise en place et validée. La seconde partie concerne la caractérisation du moteur seul. Des essais ont été menés avec une puissance de source chaude stable puis variable. À partir des résultats obtenus, un modèle empirique est développé, puis exploité dans le cadre d'une étude paramétrique du moteur. Cette étude montre l'influence importante du ratio de pression et de la vitesse de rotation sur le rendement. Dans la dernière partie, les performances globales (rendement, puissances électrique et thermique produites) du micro-cogénérateur sont évaluées. Des essais à pression et à vitesse régulées sont présentés. A partir de cartographies de fonctionnement réalisées à l’aide d’un modèle empirique, une régulation basée sur l'utilisation d'un by-pass est alors mise en place, puis testée. / The objective of this thesis is the experimental study of the energy performances of a micro combined solar heat and power (micro-CHP) unit. The prototype is composed of a solar parabolic trough collector coupled to a Hirn (superheated Rankine) cycle engine. The originalities of this project are the use of solar energy which is renewable and inexhaustible but intermittent, the direct steam generation with a reduced size parabolic trough collector (46.5 m²), the two axis tracking system and the coupling with an oil-free reciprocating steam engine. The first part of this study is focussed on the solar collector. Thermal performances under sunny and cloudy conditions are presented and the thermal efficiency is evaluated. The system dynamic is also investigated through the characterization of the inertia as well as a study of its response to perturbations. Then a control strategy is set up and validated. The second part deals with the characterization of the engine. Tests have been performed with a stable and variable heat source power. From these tests, an empirical model has been developed and used in a parametrical study. This study shows the significant influence of the pressure ratio and of the rotational speed on the efficiency of the engine. In the last part, global performances (efficiency, output thermal and electrical powers) of the entire micro-CHP unit are evaluated. Tests with controlled pressure and speed are presented. From operating maps established from an empirical model, a control strategy based on the use of a by-pass is set up and tested.
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Efektivní provoz moderních jednotek EVO / Effective operation of up-to-date waste-to-energy unitsCafourková, Tereza January 2009 (has links)
The main content of this thesis is a suggestion of computing system for efficient energy manufacture. The introduction devotes to description of up-to-date waste-to-energy units (EVO), it concentrates on Incinerator of municipal wastes of TERMIZO a.s., specifically. In the main body of this work is the data analysis of factory journal that has been implemented, results have been used as mathematical model output value. These activities are necessary for computing system suggestion. Resulting optimization of batch wasting plan with maximum economic effect for entrepreneur is the main output of this work. Conclusion consists of environmental and economic evaluation of operation of up-to-date waste-to-energy units and offers another optimization posibility.
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Development and application of a multidomaindynamic model for direct steamgeneration solar power plantRousset, Anthony January 2017 (has links)
Nowadays, one of the solutions considered in order to face the issue of global warming and to move towards a carbon neutral society relies on the use of solar energy as a renewable and bountiful primary source. And, if photovoltaic technologies account for a large part in the solar energy market, recent years have witnessed the growth of non-concentrated and concentrated solar thermal technologies. Among them, concentrated solar power technology (CSP) which uses the optical concentration of direct solar irradiation to generate high pressure and high temperature steam in the absorber tubes of the plant, has become a promising approach reaching 4.9 GWe of installed capacity by the end of 2015 [1]. However, one of the main challenges faced by CSP technology concerns the variability of solar energy related for example to sunrise, sunset, passing clouds… In addition to that, when it comes to direct steam generation, the presence of a two-phase flow regime inside the absorber tubes leads to a strong dynamic behavior of the steam generation. It is consequently necessary to be able to simulate this dynamic behavior in order to better handle the design and operation of CSP plants. Such simulation tools can then be used for the implementation and the test of reliable control systems aimed at maintaining desired operating conditions in spite of changes in solar irradiation. In this context, the National Institute for Solar Energy (INES), part of the French Alternative Energies and Atomic Energy Commission (CEA) wishes to upgrade their dynamic simulation tool that would enable its teams to reproduce the behavior of a prototype based on the Fresnel solar field technology including direct steam generation which was built and commissioned at Cadarache, Aix-en-Provence. This Master thesis work takes place within this framework and aims at developing a multi-domain dynamic model of the aforementioned prototype. To do so, three models respectively in the thermalhydraulic, the optical and the control-command domains are built and combined using a co-simulation approach relying on an in-house simulation platform called PEGASE. More specifically the development of the following models has been addressed: a thermal-hydraulic model of the two-phase flow circulating inside the vaporizer field of the prototype and realized with the thermal-hydraulic code CATHARE [2] (Advanced ThermalHydraulic Code for Water Reactor Accidents) applied to solar thermal biphasic issues, an optical model of the receiver programmed using the Modelica language and the Dymola (Dynamic Modelling Laboratory) simulation software, control-command models (PID controller, control architecture…) adapted and built upon blocks taken from a modelling library included in the PEGASE platform. Each model was first developed and tested on a standalone basis. These models were then coupled using the PEGASE co-simulation platform. A sunny day was simulated using the multi-domain model and the controllability of the plant was analyzed. At this stage, the study focused on the steam separator level regulation. A thermal-hydraulic study also focused on potential instabilities in the vaporizer that can occur under certain circumstances of water temperature at vaporizer inlet and solar heat flux. This analysis was carried out with a CATHARE standalone model. Perspectives of the present work include a complete validation of the developed models from future experimental data and further developments should aim to extend the modelling scope of the numerical simulator towards a representation of all the hydraulic parts of the CSP prototype. Control schemes and regulation tools would have to be extended as well in order to move towards a more representative control architecture of the prototype. Particularly, the steam quality at vaporizer outlet is an important variable to regulate. Indeed, this parameter is usually kept between 60% and 80% [3]. It must be high enough to limit the power consumption of the recirculation pump but not too high in order to prevent absorber dry-out. / Solenergi, som är en förnybar och riklig primärkälla, är en av de lösningarna som anses kunna lösa problemet med global uppvärmning och bidrar i omvandlingen till ett kolneutralt samhälle. Andelen fotovoltaiska teknologier på energimarknaden är övervägande, men andelen koncentrerad och ickekoncentrerad solterminsteknik har ökat under de senaste åren. Bland solterminsteknikerna är koncentrerad solenergiteknik (CSP), som använder den optiska koncentrationen av direkt strålning för att generera högtrycks- och högtemperaturånga i anläggningens absorberarrör, ett lovande tillvägagångssätt som har nått 4.9 GWe installerad kapacitet i slutet av 2015 [1]. En av de största utmaningarna med CSP-tekniken är solenergins variation vid till exempel soluppgång, solnedgång och passerande moln, vilket beror på varierad tillgång av solljus. Det finns också utmaningar med direkt ånggenerering via tvåfasflödes regimer inuti absorberarrören eftersom det leder till ett starkt dynamiskt beteende vid ånggenereringen. Det är följaktligen nödvändigt att kunna simulera detta dynamiska beteende för att bättre hantera design och drift av CSP-anläggningar. Sådana simuleringsverktyg kan sedan användas för att genomföra tester för att erhålla tillförlitliga styrsystem som upprätthåller önskade driftsförhållanden trots förändringar i solstrålningen I detta sammanhang vill National Institute for Solar Energy (INES), som är en del av den franska alternativa energikommissionen och atomenergi kommissionen (CEA), förbättra dess dynamiskt simuleringsverktyg som skulle möjliggöra för sina team att reproducera beteendet hos en prototyp baserad på Fresnel solfältsteknik inklusive direkt ånggenerering som byggts och beställts vid Cadarache, Aix-enProvence. Denna masteruppsats sker inom ramen för detta och syftar till att utveckla en dynamisk modell med flera domäner av den ovan nämnda prototypen. Tre modeller i termisk-hydraulisk, optisk och kontrollkommando domäner har byggts och kombinerats med hjälp av en co-simuleringsmetod som bygger på en intern simuleringsplattform som heter PEGASE. Mer specifikt om utvecklingen av modellerna enligt nedan: En termisk-hydraulisk modell av tvåfasflöde som cirkulerar inuti förångarens fält på prototypen har realiserats med termisk-hydraulisk kod CATHARE [2] (Advanced Thermal-Hydraulic Code for Water Reactor Accidents) som appliceras på soltermisk bifasiska frågeställningar. En optisk modell av mottagaren har programmerats med hjälp av Modelica-språket och simuleringsprogrammet Dymola (Dynamic Modeling Laboratory). Modeller av kontrollkommandon (PID-kontroller, kontrollarkitektur ...) har byggts och anpassats i moduler som hämtats från modelleringsbibliotek som ingår i PEGASE-plattformen. Varje modell utvecklades och testades på fristående basis. Modellerna kopplades sedan samman i PEGASE-co-simuleringsplattformen. En solig dag simulerades därefter med en flerdomänmodell och styrningsförmågan av anläggningen analyserades. Vid detta stadium fokuserade studien på att reglera nivån av ångseparerande. En termisk-hydraulisk studie fokuserade sedan på potentiella instabiliteter i förångaren som kan uppstå under vissa omständigheter av vatteninloppstemperatur och solvärmeflöde. Denna analys genomfördes med en CATHARE fristående modell. Perspektiven för det aktuella arbetet omfattar en fullständig validering av de utvecklade modellerna med hjälp av framtida experimentella data. Vid en vidareutveckling bör inriktningen vara att utvidga modellernas omfattning av den numeriska simulatorn till att representera alla hydrauliska delar av CSP prototypen. Styrsystem och regleringsverktyg skulle också behöva förbättras för att få en mer representativ kontroll arkitektur av prototypen. I synnerhet är ångkvaliteten vid förångarens utlopp en viktig variabel att reglera. Faktum är att den här parametern vanligtvis hålls mellan 60% och 80% [3]. Det måste vara tillräckligt högt för att begränsa recirkulationspumpens elförbrukning men inte för hög för att förhindra att absorberen torkar ut.
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