A 1-D dynamic simulation model of a new cooling system for the upcoming Gripen E aircraft has been developed in the Modelica-based tool Dymola in order to examine the cooling performance. These types of low-dimensioned simulation models, which generally are described by ordinary differential equations or differential-algebraic equations, are often used to describe entire fluid systems. These equations are easier to solve than partial differential equations, which are used in 2-D and 3-D simulation models. Some approximations and assumptions of the physical system have to be made when developing this type of 1-D dynamic simulation model. The impact from these approximations and assumptions can be examined with an uncertainty analysis in order to increase the understanding of the simulation results. Most uncertainty analysis methods are not practically feasible when analyzing large 1-D dynamic simulation models with many uncertainties, implying the importance to simplify these methods in order to make them practically feasible. This study was aimed at finding a method that is easy to realize with low computational expense and engineering workload. The evaluated simulation model consists of several sub-models that are linked together. These sub-models run much faster when simulated as standalone models, compared to running the total simulation model as a whole. It has been found that this feature of the sub-models can be utilized in an interval-based uncertainty analysis where the uncertainty parameter settings that give the minimum and maximum simulation model response can be derived. The number of simulations needed of the total simulation model, in order to perform an uncertainty analysis, is thereby significantly reduced. The interval-based method has been found to be enough for most simulations since the control software in the simulation model controls the liquid cooling temperature to a specific reference value. The control system might be able to keep this reference value, even for the worst case uncertainty combinations, implying no need to further analyze these simulations with a more refined uncertainty propagation, such as a probabilistic propagation approach, where different uncertainty combinations are examined. While the interval-based uncertainty analysis method lacks probability information it can still increase the understanding of the simulation results. It is also computationally inexpensive and does not rely on an accurate and time-consuming characterization of the probability distribution of the uncertainties. Uncertainties from all sub-models in the evaluated simulation model have not been included in the uncertainty analysis made in this thesis. These neglected sub-model uncertainties can be included using the interval-based method, as a future work. Also, a method for combining the interval-based method with aleatory uncertainties is proposed in the end of this thesis and can be examined.

Simulators for power plants can be used for many different purposes, like training for operators or for adjusting control systems, where the main objective is to perform a realistic behaviour for different operating conditions of the power plant. Due to an increased amount of variable energy sources in the power system, the role of the operators has become more important. It can therefore be very valuable for the operators to try different operating conditions like island operation. The aim of this thesis is to model the power system of a general combined-cycle power plant simulator. The model should contain certain components and have a realistic behaviour but on the same time be simple enough to perform simulations in real time. The main requirements are to simulate cold start, normal operation, trip of generator, a controlled change-over to island operation and then resynchronisation. The modelling and simulations are executed in the modelling software Dymola, version 6.1. The interface for the simulator is built in the program LabView, but that is beyond the scope of this thesis. The results show a reasonable performance of the power system with most of the objectives fulfilled. The simulator is able to perform a start-up, normal load changes, trip of a generator, change-over to island operation as well as resynchronisation of the power plant to the external power grid. However, the results from the changing-over to island operation, as well as large load losses during island operation, show an unreasonable behaviour of the system regarding the voltage magnitude at that point. This is probably due to limitations in calculation capacity of Dymola, and the problem has been left to further improvements due to lack of time. There has also been a problem during the development of a variable speed regulated induction motor and it has not been possible to make it work due to lack of enough knowledge about how Dymola is performing the calculations. Also this problem has been left to further improvements due to lack of time.

L'introduction des énergies renouvelables intermittentes, la mise en place d'une réglementation thermique qui baisse les besoins de chauffage d'un facteur 5 à 10, entraîne une re-conception des moyens de chauffage intégrant efficacité énergétique et effacement d'équipements domestiques lors des heures de pointe. Cette thèse comporte l'étude et la conception d'une PAC intégrant un stockage thermique par chaleur latente dans son condenseur. Ce stock permettra un effacement d'au moins deux heures. Les besoins d'une maison basse consommation (BBC) ont été évalués ainsi que la quantité de chaleur à stocker afin d'assurer cet effacement. Une étude sur le phénomène de changement de phase et les MCP a été menée afin de sélectionner un matériau adapté à cette application. Le phénomène de changement de phase a été modélisé en régime dynamique. Quatre matériaux candidats ont été sélectionnés et analysés par colorimétrie différentielle (DSC) avec ajustement par méthode inverse. Plusieurs structures de l'échangeur stockeur ont été proposées, simulées et optimisées et deux ont été choisies et réalisées. Les deux échangeurs réalisés ont été testés seuls et intégrés dans un système de PAC. La dernière génération a donné des résultats très encourageants pour le développement d'une PAC à stockage efficace. Finalement, l'apport de stockage a été évalué en termes d'efficacité énergétique et d'émissions de CO2. Cette PAC présente une amélioration potentielle du COP saisonnier de 20 à 30 % comparativement à des PAC air/eau et air/air du fait de la gestion intelligente du stockage/déstockage d'énergie en faisant fonctionner la PAC pendant les heures les plus favorables de la journée et en évitant les cycles courts de fonctionnement correspondant aux besoins thermiques faibles. / The introduction of intermittent renewable energies, the implementation of a thermal regulation, which decreases heating needs of a factor between 5 and 10, causes a redesign of heating systems integrating energy efficiency and the cut-off of domestic equipments during peak hours. This thesis involves the study and design of a heat pump incorporating a latent thermal storage in its condenser. This storage will allow a cut-off during at least two hours. The heating needs of a low-energy consumption house (BBC) have been estimated as well as the heat amount to be stored so as to ensure such a cut-off. A study on the phase-change phenomenon and the PCM has been carried out in order to select suitable materials for this application. A dynamic model of the phase change was also developed. Four candidate materials were selected and analyzed by tuned Differential Scaning Calorimetry (DSC) with adjustment by the inverse method. Several storing-exchanger structures have been proposed, simulated, and optimized; two of them have been realized. Both heat exchangers have been tested alone and then integrated into a heat pump system. The final generation gave very promising results for the development of an efficient heat pump with storage. Finally, the heat storage effect has been evaluated in terms of energy efficiency and CO2 emissions. This heat pump presents potential improvement of the seasonal COP between 20% and 30% compared to air-to-water and air-to-air heat pumps because of the smart monitoring of the energy storage/delivery due to the heat pump operation during the most favorable hours of the day and by avoiding short cycles operation corresponding to low heating needs.

A simulation model for an automatic gearbox with primary retarder has been constructedand implemented, in this thesis. Together with other modelled vehicle components, thismodel could for example be used for fuel consumption estimation or optimizing vehicleparameters.The mechanical components and the control system inside the automatic gearbox weremodelled separately and then assembled into the nal gearbox model, using the objectorientedprogramming language Modelica. Modelica ensures that each individual componentcan be reused in other models.The gearbox model was validated through a number of test cycles designed to capturedierent vehicle behaviours. The test cycles were recreated in the simulation environmentand the simulation results could be compared to a real vehicle performing the same tests.Validation showed that the model succeeded in its goal, that the implemented model isreproducing similar behaviour as the real gearbox. With gear shifts taking place in aboutthe same situations and converter locking/unlocking occurring the same time in the simulationsas in the real vehicle testing. / I det här examensarbetet har en simuleringsmodell för en automatisk växellåda med primär retarder utvecklats och implementerats. Tillsammans med andra modeller från fordonoch drivlina skulle denna simuleringsmodell kunna användas för att uppskatta ett fordonsbränsleförbrukning eller till att optimera olika fordonsparametrar.De olika mekaniska komponenterna samt kontrollsystemet i växellådan modellerades separat.Dessa modeller kunde sedan sammanfogas för att bygga den slutliga växellådsmodellen.Alla modeller implementerades i det objektorienterade programmeringsspråket Modelica,som tillåter en stor återanvändningsbarhet till vardera enskild komponent.Den implementerade modellen verierades genom ett antal provcykler, utformade för attfånga olika beteenden hos växellådan. Dessa cykler har återskapats i simuleringsmiljön ochmed det kunde resultat från simuleringar jämföras mot data från ett verkligt fordon somutförde samma prov.Från verieringen har slutsatsen dragits att modellen uppfyllde målen med projektet. Målen var, att den slutliga simuleringsmodellen visar ett liknande beteende som en växellåda i ett verkligen fordon. Växlingar och låsning/upplåsning hos momentomvandlareninträande vid ungefär samma situationer i simuleringarna som i provningen med det verkligafordonet.

Le fonctionnement de la pile à combustible (PAC) de type PEM (à membrane polymère) est encore soumis à de nombreuses incertitudes, aux natures différentes, qui affectent ses performances électriques, sa fiabilité et sa durée de vie. L'objectif général de cette thèse est de proposer une méthode d'aide à l'évaluation de la fiabilité des PAC par la simulation ; la fiabilité étant vue ici comme la garantie d’accéder à un niveau de performance électrique donné dans les différentes conditions d’usage envisagées pour la PAC. La démarche proposée s’appuie sur un couplage physico-fiabiliste où la complexité des phénomènes physiques présents dans la pile est prise en compte par une modélisation de connaissance, dynamique, symbolique et acausale, développée dans l’environnement Modelica - Dymola. La modélisation retenue, monodimensionnelle, non isotherme inclut une représentation diphasique des écoulements fluidiques pour mieux retranscrire la complexité des échanges d’eau dans le coeur de la pile PEM. La modélisation permet aussi d’intégrer des incertitudes sur certains de ses paramètres physiques et semi-empiriques (classés en trois catégories : opératoires, intrinsèques et semi-empiriques) puis d’entreprendre, par des tirages de Monte-Carlo, la modélisation probabiliste des conséquences des incertitudes injectées sur la performance d’une PAC. Il est ainsi possible, par la suite, d’estimer la fiabilité d’une PAC par le calcul de la probabilité que la performance électrique reste supérieure à un seuil minimal à définir en fonction de l’application. Une analyse physico-fiabiliste détaillée a été menée en introduisant à titre d’exemple une incertitude sur la valeur de la porosité de la couche de diffusion cathodique d’une PAC de type PEM (coefficients de variation retenus : 1%, 5% et 10%). L’étude des conséquences de cette incertitude sur la tension et l’impédance d’une PAC a été menée en réalisant un plan d’expériences numériques et en mettant en oeuvre différents outils d’analyse statistique : graphes des effets, analyses de la variance, graphes des coefficients de variation des distributions en entrée et sortie du modèle déterministe. Dans cet exemple d’analyse et dans les conditions d’usages considérées, le taux de fiabilité prévisionnel (probabilité pour que la cellule de pile fournisse un minimum de tension de 0.68V) a été estimé à 91% avec un coefficient de variation d’entrée à 10%. / The Proton Exchange Membrane Fuel Cell (PEMFC) operation is subject to inherent uncertainty in various material, design and control parameters, which leads to performance variability and impacts the cell reliability. Some inaccuracies in the building process of the fuel cell (in the realization of the cell components and also during the assembly of the complete fuel cell stack), some fluctuations in the controls of the operating parameters (e.g. cell and gas temperatures, gas pressures, flows and relative humidity rates) affect the electrical performance of the cell (i.e. cell voltage) as well as its reliability and durability. For a given application, the selections of the different materials used in the various components of the electrochemical cell, the choices in the cell design (geometrical characteristics / sizes of the cell components) correspond to tradeoffs between maximal electrical performances, minimal fuel consumption, high lifespan and reliability targets, and minimal costs.In this PhD thesis, a novel method is proposed to help evaluating the reliability of a PEMFC stack. The aim is to guarantee a target level of electrical performance that can be considered as sufficient to meet any application requirements. The approach is based on the close coupling between physical modeling and statistical analysis of reliability. The complexity of the physical phenomena involved in the fuel cell is taken into account through the development of a dynamical, symbolic, acausal modeling tool including physical and semi-empirical parameters as well. The proposed knowledge PEMFC model is one-dimensional, non-isothermal and it includes a two-phase fluidic flow representation (each reactant is considered as a mix of gases and liquid water) in order to better take into account the complexity of the water management in the cell. The modeling is implemented using the MODELICA language and the DYMOLA software; one of the advantages of this simulation tool is that it allows an effective connection between multi-physical modeling and statistical treatments. In this perspective, the modeling is done with the aim of having as much relevant physical parameters as possible (classified in our work as operating, intrinsic, and semi-empirical parameters). The different effects of these parameters on the PEMFC electrical behavior can be observed and the performance sensitivity can be determined by considering some statistical distributions of input parameters, which is a step towards reliability analysis.A detailed physical and reliability analysis is conducted by introducing (as an example) an uncertainty rate in the porosity value of the cathodic Gas Diffusion Layer (coefficients of variance equal to 1%, 5% and 10%). The study of the uncertainty consequences on the cell voltage and electrical impedance is done through a design of numerical experiments and with the use of various statistical analysis tools, namely: graphs of the average effects, statistical sensitivity analyses (ANOVAs), graphs displaying the coefficients of variances linked with the statistical distributions observed in the inputs and outputs of the deterministic model. In this example of analysis and in the considered cell operating conditions, the provisional reliability rate (probability that the cell voltage is higher than 0.68V) is estimated to 91% with an input coefficient of variance equal to 10%.

Les enjeux énergétiques et environnementaux liés au réchauffement climatique amènent à généraliser la sobriété énergétique des bâtiments neufs ainsi que la production locale d’énergie à l’horizon 2020. Ce travail de thèse se concentre sur le secteur de la maison individuelle qui représente près de la moitié des logements neufs construits en France pour un volume d’environ 200000 unités par an.Le contexte de la maison individuelle à énergie positive 100 % solaire consiste à rechercher les compromis entre le niveau de performance du bâti qui détermine les besoins en énergie et la capacité des équipements à valoriser l’énergie solaire pour d’une part subvenir aux besoins en chaleur pour assurer le chauffage et la production d’eau chaude sanitaire, et d’autre part produire l’électricité nécessaire à l’éclairage et aux autres usages spécifiques (matériels électroménager, vidéo, etc.). Après un examen des différents concepts de bâtiments à énergie positive, une analyse a été menée pour identifier les solutions techniques de systèmes solaires combinés capables de fournir le double service de production d’eau chaude et de chauffage. Un modèle détaillé a été développé dans l’environnement Dymola et vérifié par inter-comparaison de modèles à l’échelle des composants. Un algorithme de contrôle original a été mis au point pour maximiser la performance globale du système.Une première étude paramétrique a montré que ce système est capable dans certaines conditions de couvrir près de 80 % des besoins en chaleur de la maison étudiée. Néanmoins, son dimensionnement demeure complexe et la recherche de compromis entre la sobriété de la maison et le dimensionnement des systèmes solaires thermiques et photovoltaïques doit s’appuyer sur un algorithme d’optimisation multi-objectifs adapté.Un chapitre est donc consacré à l’élaboration d’un algorithme d’optimisation multi- objectifs qui s’appuie sur la méthode des colonies d’abeilles virtuelles. Cette approche s’est avérée particulièrement pertinente vis à vis du problème (paramètres discrets, continus et qualitatifs) à caractère multiobjectifs(maximiser la valorisation du solaire thermique pour le chauffage d’une part et pour la production d’eau chaude d’autre part, minimiser la consommation d’énergie conventionnelle) et sous contrainte car seules les solutions à bilan d’énergie positif sur l’année seront retenues. L’algorithme d’optimisation développé ici a été confronté à une série de problèmes classiques et a démontré sa capacité à construire l’ensemble des solutions avec un nombre relativement faible d’évaluations du modèle.Le dernier chapitre présente deux applications de conception de maisons à énergie positive. La première se situe en région bordelaise alors que la seconde est située à proximité de Strasbourg. Ces deux conditions climatiques permettent de mettre en évidence la capacité de l’algorithme d’optimisation à proposer un éventail de solutions optimales présentant des compromis différents en termes de performance du bâti et de dimensionnement des équipements solaires. Enfin, un outil d’aide à la décision permet d’explorer les fronts optimaux pour dégager les solutions à retenir. / With energy-related and environmental climate change challenges, energy sobriety and local energy production are yet to become a mainstream practice for new buildings construction by 2020. This works focuses on single-family houses which in France represent half of new buildings constructions with 200000 new units new units each year. Near zero energy single-family houses with 100 % solar energy consists on compromising between performance of building envelope which defines energy needs and the ability for equipments to value free solar energy. Hence solar energy must be able to cover space heating and domestic hot waterdemands but also provide enough energy for lightning and other specific uses such as domestic appliances.After a literature review of near zero energy house concepts, an analysis was undertaken to providea clear view of solar combi-systems technical solutions with the ability to provide enough energyfor both needs : space heating and domestic hot water. Using Dymola environment a detailed modelwas developed and its consistency was checked by inter-comparison at component scale. An innovative control algorithm has been worked out to maximize the solar system’s global performance. Afirst parametric study has shown that the system was able to cover close to 80 % of house heat requirement. However sizing of a solar combi-system is a complex task and requires to find compromises between building sobriety, solar thermal energy efficiency, and photovoltaics solar energy sizing. Because of the problem’s complexity, a decision aid tool with an appropriate multi-criteria optimizationalgorithm is required.To that end a chapter is dedicated to the development of a multi-criteria optimization algorithm based on artificial bee colony behavior. This approach has proved to be quite effective to solve the problem and to handle continuous, discrete and qualitative decision variables. Chosen solution was constrained to have a positive energy balance and must maximize solar space heating and domestic fraction in a view to reduce total energy consumption. A validation process has also been set up and the developed optimization algorithm has proved its ability to solve standard problems with a fairlyshort number of evaluations. Adopted methodology was illustrated by two applications of the design phase of a near zero energydetached house. First one is located at Bordeaux an second one in Strasbourg. Selected climate conditions emphasize the ability of the proposed approach to identify a wide range of optimal solutions showing differences within the building’s performance as well as the solar system sizing. Lastly a decision aid tool allows to explore optimal front in a convenient way to shape adapted solutions.

Models have become an indispensable tool within most industrial sectors and are used to reduce costs, enhance the performance of a system etc. The computer support within modelling is extensive, whereof the programming language Modelica is eminent, especially for multi-domain models. Dymola, a commercial program, is built on Modelica and is foremost used for simulation purposes, but many applications for which models are useful are not supported by Dymola. Instead other tools, e.g. Matlab, could be used to exploit the full potential of a model, which means that it first would be needed to be translated. This master's thesis examines one of the possible ways to accomplish this. Specifically the possibility to translate Modelica-models via an XML file, generated by Dymola, is examined. The structure and content of this file is explored, and based thereupon a software is implemented in Python, which successfully translates the models constituting the base for this thesis. Specifically the method was developed on a model of a sub-system of Saab 39 Gripen air-plane. Besides porting models between different languages, it is of great interest to determine how well a model describes the system on which it is based. Hence a new method for model validation is developed using the Matlab Fault Diagnosis Toolbox, which also determines the Matlab syntax of the Modelica translation. The novelty with the developed method, compared to traditional model validation methods, is that it is equation based. It is meant to point out specifically which equations are poorly fitted to validation data. On a simple example model the method was successfully used to isolate a poorly fitted equation. This is accomplished by introducing faults to the equations and generating residuals, based on sets of over-determined equations. As a measure of the modelling error the estimation error of the simulated residuals is used, which are weighted together depending on the fault properties of the residuals.

Engineering aircraft systems is a complex task. Therefore models and computer simulations are needed to test functions and behaviors of non existing systems, reduce testing time and cost, reduce the risk involved and to detect problems early which reduce the amount of implementation errors. At the section Vehicle Simulation and Thermal Analysis at Saab Aeronautics in Linköping every basic aircraft system is designed and simulated, for example the fuel system. Currently 2-dimensional rectangular blocks are used in the simulation model to represent the fuel tanks. However, this is too simplistic to allow a more detailed analysis. The model needs to be extended with a more complex description of the tank geometry in order to get a more accurate model. This report explains the different steps in the developed methodology for combining 3-dimensional geometry models of any fuel tank created in CATIA with dynamic simulation of the fuel system in Dymola. The new 3-dimensional representation of the tank in Dymola should be able to calculate fuel surface location during simulation of a maneuvering aircraft.  The first step of the methodology is to create a solid model of the fuel contents in the tank. Then the area of validity for the model has to be specified, in this step all possible orientations of the fuel acceleration vector within the area of validity is generated. All these orientations are used in the automated volume analysis in CATIA. For each orientation CATIA splits the fuel body in a specified number of volumes and records the volume, the location of the fuel surface and the location of the center of gravity. This recorded data is then approximated with the use of radial basis functions implemented in MATLAB. In MATLAB a surrogate model is created which are then implemented in Dymola. In this way any fuel surface location and center of gravity can be calculated in an efficient way based on the orientation of the fuel acceleration vector and the amount of fuel. The new 3-dimensional tank model is simulated in Dymola and the results are compared with measures from the model in CATIA and with the results from the simulation of the old 2-dimensional tank model. The results shows that the 3-dimensional tank gives a better approximation of reality and that there is a big improvement compared with the 2-dimensional tank model. The downside is that it takes approximately 24 hours to develop this model. / Att utveckla ett nytt flygplanssystem är en väldigt komplicerad arbetsuppgift. Därför används modeller och simuleringar för att testa icke befintliga system, minska utvecklingstiden och kostnaderna, begränsa riskerna samt upptäcka problem tidigt och på så sätt minska andelen implementerade fel. Vid sektionen Vehicle Simulation and Thermal Analysis på Saab Aeronautics i Linköping designas och simuleras varje grundflygplanssystem, ett av dessa system är bränslesystemet. För närvarande används 2-dimensionella rätblock i simuleringsmodellen för att representera bränsletankarna, vilket är en väldigt grov approximation. För att kunna utföra mer detaljerade analyser behöver modellerna utökas med en bättre geometrisk beskrivning av bränsletankarna. Denna rapport går igenom de olika stegen i den framtagna metodiken för att kombinera 3- dimensionella tankmodeller skapade i CATIA med dynamisk simulering av bränslesystemet i Dymola. Den nya 3-dimensionella representationen av en tank i Dymola bör kunna beräkna bränsleytans läge under en simulering av ett manövrerande flygplan. Första steget i metodiken är att skapa en solid modell av bränslet som finns i tanken. Därefter specificeras modellens giltighetsområde och alla tänkbara riktningar hos accelerationsvektorn som påverkar bränslet genereras, dessa används sedan i den automatiserade volymanalysen i CATIA.  För varje riktning delar CATIA upp bränslemodellen i ett bestämt antal delar och registrerar volymen, bränsleytans läge samt tyngdpunktens position för varje del. Med hjälp av radiala basfunktioner som har implementerats i MATLAB approximeras dessa data och en surrogatmodell tas fram, denna implementeras sedan i Dymola. På så sätt kan bränsleytans och tyngdpunktens läge beräknas på ett effektivt sätt, baserat på riktningen hos bränslets accelerationsvektor samt mängden bränsle i tanken. Den nya 3-dimensionella tankmodellen simuleras i Dymola och resultaten jämförs med mätningar utförda i CATIA samt med resultaten från den gamla simuleringsmodellen. Resultaten visar att den 3-dimensionella tankmodellen ger en mycket bättre representation av verkligheten och att det är en stor förbättring jämfört med den 2-dimensionella representationen. Nackdelen är att det tar ungefär 24 timmar att få fram denna 3-dimensionella representation.

This thesis covers the modelling of a Heat Recovery Steam Generator (HRSG) in a Combined Cycle Power Plant(CCPP). This kind of power plant has become more and more utilized because of its high efficiency and low emissions. The HRSG plays a central role in the generation of steam using the exhaust heat from the gas turbine. The purpose of the thesis was to develop efficient dynamic models for the physical components in the HRSG using the modelling and simulation software Dymola. The models are then to be used for simulations of a complete CCPP.The main application is to use the complete model to introduce various disturbances and study their consequences inthe different components in the CCPP by analyzing the simulation results. The thesis is a part of an ongoingdevelopment process for the dynamic simulation capabilities offered by the Solution department at SIT AB. First, there is a theoretical explanation of the CCPP components and control system included in the scope of this thesis. Then the development method is described and the top-down approach that was used is explained. The structure and equations used are reported for each of the developed models and a functional description is given. Inorder to ensure that the HRSG model would function in a complete CCPP model, adaptations were made and tuning was performed on the existing surrounding component models in the CCPP. Static verifications of the models are performed by comparison to Siemens in-house software for static calculations. Dynamic verification was partially done, but work remains to guarantee the validity in a wide operating range. As a result of this thesis efficient models for the drum boiler and its control system have been developed. An operational model of a complete CCPP has been built. This was done integrating the developed models during the work with this thesis together with adaptations of already developed models. Steady state for the CCPP model is achieved during simulation and various disturbances can then be introduced and studied. Simulation time for a typical test case is longer than the time limit that has been set, mainly because of the gas turbine model. When using linear functions to approximate the gas turbine start-up curves instead, the simulation finishes within the set simulation time limit of 5 minutes for a typical test case.

No description available.