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Dissertations / Theses on the topic 'Energy modeling and simulation'

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Published: 4 June 2025
Last updated: 23 June 2025

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1

Johari, Fatemeh. "Urban building energy modeling : A systematic evaluation of modeling and simulation approaches." Licentiate thesis, Uppsala universitet, Byggteknik och byggd miljö, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-428021.

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Urban energy system planning can play a pivotal role in the transition of urban areas towards energy efficiency and carbon neutrality. With the building sector being one of the main components of the urban energy system, there is a great opportunity for improving energy efficiency in cities if the spatio-temporal patterns of energy use in the building sector are accurately identified. A bottom-up engineering energy model of buildings, known as urban building energy model (UBEM), is an analytical tool for modeling buildings on city-levels and evaluating scenarios for an energy-efficient built environment, not only on the building-level but also on the district and city-level. Methods for developing an UBEM vary, yet, the majority of existing models use the same approach to incorporating already established building energy simulation software into the main core of the model. Due to difficulties in accessing building-specific information on the one hand, and the computational cost of UBEMs on the other hand, simplified building modeling is the most common method to make the modeling procedure more efficient. This thesis contributes to the state-of-the-art and advancement of the field of urban building energy modeling by analyzing the capabilities of conventional building simulation tools to handle an UBEM and suggesting modeling guidelines on the zoning configuration and levels of detail of the building models. According to the results from this thesis, it is concluded that with 16% relative difference from the annual measurements, EnergyPlus is the most suitable software that can handle large-scale building energy models efficiently. The results also show that on the individual building-level, a simplified single-zone model results in 6% mean absolute percentage deviation (MAPD) from a detailed multi-zone model. This thesis proposes that on the aggregated levels, simplified building models could contribute to the development of a fast but still accurate UBEM.
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Simonsson, Johan. "Towards efficient modeling and simulation of district energy systems." Licentiate thesis, Luleå tekniska universitet, Signaler och system, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-83242.

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Dynamic simulation of district energy systems has an increased importance in the transition towards renewable energy sources, lower temperature district heating grids and waste heat recovery from industrial plants and data centers. However, a city-scale, automatically generated and updated simulator that can be used for the whole lifecycle of the plant remains a distant vision. Physics based models are often used for planning and validation, but the complexity is too high to use the models for optimization and automatic control, or for longer time spans. In this thesis, the experiences and challenges from previous district heating simulation projects using a co-simulation approach are summarized, with corresponding research gaps and proposed research directions. Two of the identified shortcomings are investigated in more detail in the thesis:  First, a robust and computationally efficient method for prediction of the heat load for buildings is proposed. A deterministic dynamic model is used to predict the space heating load, and a latent variable model using Fourier basis functions predicts the heat load used for e.g. hot tap water and ventilation. The prediction model validity is shown on a multi-dwelling building located in Luleå, Sweden.  Second, a probabilistic model based on Gaussian Processes is used to simulate the temperature dynamics of a district heating pipe. The model is trained and validated against a state-of-the-art physics based pipe model. It is shown that the model both replicates the behavior of the reference model, and that it can account for uncertainty of the inputs. By employing a kernel exploiting the underlying physics, many shortcomings of Gaussian Process models can be mitigated.  The results suggest that a mix of physics based and probabilistic methods can be one way forward towards a digital twin of a city-scale district energy system. Natural extensions to the published papers would be to research how the methods can be applied to a larger scale district energy system.
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Bånkestad, Maria. "Modeling, Simulation and Dynamic control of a Wave Energy Converter." Thesis, KTH, Numerisk analys, NA, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-134104.

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The energy in ocean waves is a renewable energy resource not yet fully exploited. Research in converting ocean energy to useful electricity has been ongoing for about 40 years, but no one has so far succeed to do it at sufficiently low cost. CorPower Ocean has developed a method, which in theory can achieve this. It uses a light buoy and a control strategy called Phase Control. The purpose of this thesis is to develop a mathematical model of this method - using LinearWave Theory to derive the hydrodynamic forces - and from the simulated results analyze the energy output of the method. In the process we create a program that will help realizing and improving the method further. The model is implemented and simulated in the simulation program Simulink. On the basis of the simulated results, we can concludes that the CorPower Ocean method is promising. The outcome shows that the energy output increases - up to five times- compared to conventional methods.<br>Vågenergi är en förnyelsebar energikälla som ännu inte utnyttjas fullt ut. Forskning inom konvertering av vågenergi till användbar elektricitet har pågått i cirka 40 år, men ingen har hittills lyckas att göra det tillräckligt kostnadseffektivt. CorPower Ocean har utvecklat en metod, som i teorin kan uppnå detta. De använder en lätt boj och en kontrollstrategi kallad Phase Control. Syftet med detta examensarbete är att utveckla en matematisk modell av metoden -genom att använda Linear Wave Theory för att härleda de hydrodynamiska krafterna -och från de simulerade resultaten analysera energiutbytet. Under arbetets gång skapades också ett simuleringsprogram som hjälpmedel till att realisera och förbättra metoden. Modellen implementeras och simuleras i programmet Simulink. Utifrån de simulerade resultaten kan vi dra slutsatsen att CorPower Oceans metod är lovande. Resultatet visar att energiutbytet ökar -upp till fem gånger - jämfört med konventionella metoder.
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Chitas, Dimosthenis. "Modeling and Simulation of a Small-Scale Polygeneration Energy System." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175830.

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The polygeneration is an innovative and sustainable solution which has become an attractive concept. The simultaneous production of electricity, heating and cooling including hot and cold water respectively in autonomous smaller energy systems can manage a more flexible and environmentally friendly system. Furthermore distributed generation and micro scale polygeneration systems can perform the increase of the utilized renewable energy sources in the power generation. The aforementioned energy systems can consist of several power generation units however the low emission levels, the low investment costs and the fuel flexibility of microturbines are some of the reasons that the study of the microturbines in polygeneration systems is a crucial necessity. In this study, an autonomous small-scale polygeneration energy system is investigated and each component is analyzed. The components of the system are a microturbine, a heat recovery boiler, a heat storage system and an absorption chiller. The purpose of this work is the development of a dynamic model in Matlab/Simulink and the simulation of this system, aiming to define the reliability of the model and understand better the behavior of such a system. Special focus is given to the model of the microturbine due to the complexity and the control methods of this system. The dynamic model is mainly based on thermodynamic equations and the control systems of the microturbine on previous research works. The system has as a first priority the electricity supply while thermal load is supplied depending on the electric demand. The thermal load is supplied by hot water due to the heat recovery which takes place at the heat recovery boiler from the flue gases of the microturbine. Additionally the design of the system is investigated and an operational strategy is defined in order to ensure the efficient operation of the system. For this reason, after creating the load curves for a specific load, two different cases are simulated and a discussion is done about the simulation results and the future work.
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Saadon, Syamimi. "Modeling and simulation of a ventilated building integrated photovoltaic/thermal (BIPV/T) envelope." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0049.

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La demande d'énergie consommée par les habitants a connu une croissance significative au cours des 30 dernières années. Par conséquent, des actions sont menées en vue de développement des énergies renouvelables et en particulier de l'énergie solaire. De nombreuses solutions technologiques ont ensuite été proposées, telles que les capteurs solaires PV/T dont l'objectif est d'améliorer la performance des panneaux PV en récupérant l’énergie thermique qu’ils dissipent à l’aide d’un fluide caloporteur. Les recherches en vue de l'amélioration des productivités thermiques et électriques de ces composants ont conduit à l'intégration progressive à l’enveloppe des bâtiments afin d'améliorer leur surface de captation d’énergie solaire. Face à la problématique énergétique, les solutions envisagées dans le domaine du bâtiment s’orientent sur un mix énergétique favorisant la production locale ainsi que l’autoconsommation. Concernant l’électricité, les systèmes photovoltaïques intégrés au bâtiment (BIPV) représentent l’une des rares technologies capables de produire de l’électricité localement et sans émettre de gaz à effet de serre. Cependant, le niveau de température auquel fonctionnent ces composants et en particulier les composants cristallins, influence sensiblement leur efficacité ainsi que leur durée de vie. Ceci est donc d’autant plus vrai en configuration d’intégration. Ces deux constats mettent en lumière l’importance du refroidissement passif par convection naturelle de ces modules. Ce travail porte sur la simulation numérique d'une façade PV partiellement transparente et ventilée, conçu pour le rafraichissement en été (par convection naturelle) et pour la récupération de chaleur en hiver (par ventilation mécanique). Pour les deux configurations, l'air dans la cavité est chauffé par la transmission du rayonnement solaire à travers des surfaces vitrées, et par les échanges convectif et radiatif. Le système est simulé à l'aide d'un modèle multi-physique réduit adapté à une grande échelle dans des conditions réelles d'exploitation et développé pour l'environnement logiciel TRNSYS. La validation du modèle est ensuite présentée en utilisant des données expérimentales du projet RESSOURCES (ANR-PREBAT 2007). Cette étape a conduit, dans le troisième chapitre du calcul des besoins de chauffage et de refroidissement d'un bâtiment et l'évaluation de l'impact des variations climatiques sur les performances du système. Les résultats ont permis enfin d'effectuer une analyse énergétique et exergo-économique<br>The demand of energy consumed by human kind has been growing significantly over the past 30 years. Therefore, various actions are taken for the development of renewable energy and in particular solar energy. Many technological solutions have then been proposed, such as solar PV/T collectors whose objective is to improve the PV panels performance by recovering the heat lost with a heat removal fluid. The research for the improvement of the thermal and electrical productivities of these components has led to the gradual integration of the solar components into building in order to improve their absorbing area. Among technologies capable to produce electricity locally without con-tributing to greenhouse gas (GHG) releases is building integrated PV systems (BIPV). However, when exposed to intense solar radiation, the temperature of PV modules increases significantly, leading to a reduction in efficiency so that only about 14% of the incident radiation is converted into electrical energy. The high temperature also decreases the life of the modules, thereby making passive cooling of the PV components through natural convection a desirable and cost-effective means of overcoming both difficulties. A numerical model of heat transfer and fluid flow characteristics of natural convection of air is therefore undertaken so as to provide reliable information for the design of BIPV. A simplified numerical model is used to model the PVT collector so as to gain an understanding of the complex processes involved in cooling of integrated photovoltaic arrays in double-skin building surfaces. This work addresses the numerical simulation of a semi-transparent, ventilated PV façade designed for cooling in summer (by natural convection) and for heat recovery in winter (by mechanical ventilation). For both configurations, air in the cavity between the two building skins (photovoltaic façade and the primary building wall) is heated by transmission through transparent glazed sections, and by convective and radiative exchange. The system is simulated with the aid of a reduced-order multi-physics model adapted to a full scale arrangement operating under real conditions and developed for the TRNSYS software environment. Validation of the model and the subsequent simulation of a building-coupled system are then presented, which were undertaken using experimental data from the RESSOURCES project (ANR-PREBAT 2007). This step led, in the third chapter to the calculation of the heating and cooling needs of a simulated building and the investigation of impact of climatic variations on the system performance. The results have permitted finally to perform the exergy and exergoeconomic analysis
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6

Djafarzadeh, Roxana. "Modeling and simulation of cellular metabolism and energy production by mitochondria." Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/26890.

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It is the intent of this thesis to investigate and develop a simulation model for metabolic pathways in the cells, namely, Glycolysis and Krebs cycle, using the DEVS formalism and the CD++ tool, then to further improve it to complete virtual mitochondrion. The hierarchical nature of DEVS makes it ideal for describing naturally hierarchical systems as the Cell, while its discrete-event approach improves performance due to the asynchronous nature of the events occurring in the cell. Simultaneously, as DEVS is a timed-based modeling approach, timing of the chemical reactions can be adequately represented. The models were developed using the CD++ toolkit, a modeling tool for simulation of complex physical systems that can be used to simulate a variety of models. CD++ server permits the execution and visualization of the results with sophisticated and easy-to-use Graphical User Interfaces. A precise and easy to use simulation environment for biological models of glycolysis and Krebs cycle was created, and the results presented show the potential of this approach.
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7

Zhang, Hanlu. "Modeling, simulation, and optimization of miniature tribo-electret kinetic energy harvesters." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC100.

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La récupération d'énergie dans l'environnement ambiant est une bonne solution d'alimentation durable et complémentaire dans certains produits électroniques grand public, réseaux de capteurs distribués sans fil, dispositifs portables ou implantables, systèmes "Internet of Things" avec beaucoup de nœuds, etc. par rapport aux batteries. Les mouvements et les vibrations sont des sources d’énergie les plus disponibles à cet effet. Les dispositifs collectant de l’énergie cinétique à petite échelle sont appelés récupérateurs d'énergie cinétique (RECs). Les RECs avec électrets (E-RECs) sont un type de RECs électrostatiques qui utilisent des électrets (diélectriques avec charges quasi permanentes) comme source de tension de polarisation, et qui peuvent générer de l'électricité grâce à l'effet d'induction électrostatique lorsque la la capacitance des E-RECs varie du fait des mouvements/vibrations. Cette thèse vise à étudier les caractéristiques de sortie transitoires des E-RECs à la fois par des simulations théoriques et des mesures expérimentales, et à optimiser l’efficacité et la puissance de sortie des E-RECs par charge triboélectrique et par d'autres méthodes adaptées à leurs caractéristiques de sortie, qui sont essentielles pour améliorer la performance des E-RECs par mouvements/vibrations.Tout d'abord, les caractéristiques de sortie à amplitude variable d'un E-REC en mode contact-séparation (CS) dans des cycles de travail transitoires sont examinées via les résultats de la simulation basés sur un modèle de circuit équivalent détaillé. Ces caractéristiques de sortie à amplitude variable sont attribuées au décalage du cycle de transfert de charge par rapport au cycle de mouvement d'excitation. Les influences de la condition initiale et de la résistance de charge sur la variation des pics de tension de sortie d'un tribo-électret REC (TE-REC) en mode CS réalisé avec un film électret en polytétrafluoroéthylène (PTFE) one été étudiées en détail et vérifiées à la fois par simulations et expériences.Deuxièmement, une méthode d'optimisation du temps de contact est utilisée pour améliorer la puissance de sortie et l'efficacité du TE-REC en mode CS avec une résistance de charge de 100 MΩ. L'énergie convertie théorique maximale par cycle de travail du TE-REC est analysée. Nous avons aussi étudié les influences de plusieurs facteurs défavorables qui généralement réduiraient la conversion d'énergie par cycle de travail du TE-REC. L’optimisation de l'intervalle d'air maximal et la méthode tribo-charge sont également utilisées pour améliorer la puissance moyenne sortie du TE- REC avec une surface de 4 cm × 4 cm, de ~ 150 μW à ~ 503 μW.Troisièmement, une méthode innovante et facile a été développée pour charger le film polymère électret en éthylène propylène fluoré (FEP) par pelage de ruban adhésif, sans utiliser de source de haute tension électrique. La distribution du potentiel de la surface du film de FEP est fortement modifiée après plusieurs pelages au ruban adhésif. Par conséquence, la tension et le courant de sortie des TE-REC fabriqués avec le film FEP traités sont beaucoup améliorés. Pour un TE-REC flexible d’une surface de 64 cm2 soufflé par du vent, une amélioration évidente d'environ 692% de la puissance de sortie, correspondant 2,5 μW à environ 19,8 μW, a été obtenue par cette méthode<br>Harvesting energy from the ambient environment is a good sustainable and complementary power supply solution in some consumer electronics, distributed wireless sensor networks, wearable or implantable devices, "Internet of Things" systems with lots of nodes, etc. in comparison with batteries. The ubiquitous kinetic energy in various motions and vibrations is one of the most available energy sources for such a purpose. The electret kinetic energy harvesters (E-KEHs) is one type of electrostatic kinetic energy harvesters using electrets (dielectrics with quasi-permanent charges) as the biasing voltage source, which can generate electricity based on the electrostatic induction effect when the capacitance of the E-KEHs is changed by the motions/vibrations. This thesis aims to investigate the transitory output characteristics of E-KEHs by both theoretical simulations and experimental measurements and to optimize the efficiency and output power of E-KEHs by tribo-charging and other methods adapted to their output characteristics, which are significant to improving the performance of E-KEHs.Firstly, the amplitude-variable output characteristics of a contact-separation (CS) mode E-KEH in transitory working cycles are investigated via the simulation results based on a detailed equivalent circuit model. These amplitude-variable output characteristics are attributed to the lag of the charge-transfer cycle behind the excitation motion cycle. The influences of both the initial condition and the load resistance on the variation in the output voltage peaks of a tribo-electret KEH (TE-KEH) are studied in detail and verified by both simulated and experimental data of a CS mode TE-KEH made with polytetrafluoroethylene (PTFE) electret film.Secondly, based on the analysis of the amplitude-variable output characteristics, a contact time optimization method is used to improve the output power and efficiency of the CS mode TE-KEH with a large load resistance of 100 MΩ. The theoretical maximum output energy per working cycle of the TE-KEH is analyzed. Several usually unfavorable factors that would reduce the practical output energy per working cycle of the TE-KEH are discussed. The maximum air gap optimization and the tribo-charging methods are also used together to further improve the average output power of the 4 cm × 4 cm sized TE-KEH from ~150 μW to ~503 μW.Thirdly, an innovative and facile tape-peeling tribo-charging method is developed to charge the fluorinated ethylene propylene (FEP) polymer film to make electrets without using any high voltage source. The surface potential distribution of the FEP film is apparently changed after several tape-peeling tribo-charging treatments. Consequently, the output voltage and current of TE-KEHs made with the FEP film are greatly improved. For a 64 cm2 sized flexible TE-KEH to harvest kinetic energy from wind, an apparent ~692% improvement in the output power from ~2.5 μW to ~19.8 μW was obtained by the tape-peeling charging method
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8

Yurkovich, Benjamin J. "Electrothermal Battery Pack Modeling and Simulation." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281632214.

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9

Gebben, Florian. "Modeling and Simulation of Solar Energy Harvesting Systems with Artificial Neural Networks." Thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-29626.

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Simulations are a good method for the verification of the correct operation of solar-powered sensor nodes over the desired lifetime. They do, however, require accurate models to capture the influences of the loads and solar energy harvesting system. Artificial neural networks promise a simplification and acceleration of the modeling process in comparison to state-of-the-art modeling methods. This work focuses on the influence of the modeling process's different configurations on the accuracy of the model. It was found that certain parameters, such as the network's number of neurons and layers, heavily influence the outcome, and that these factors need to be determined individually for each modeled harvesting system. But having found a good configuration for the neural network, the model can predict the supercapacitor's charge depending on the solar current fairly accurately. This is also true in comparison to the reference models in this work. Nonetheless, the results also show a crucial need for improvements regarding the acquisition and composition of the neural network's training set.
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Calance, Marius Alexandru. "Energy Losses Study on District Cooling Pipes : Steady-state Modeling and Simulation." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-18490.

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Distributionsförluster är en viktig faktor i fjärrenergisystem. Genom att optimera förluster i sådana system, kan både ekonomiska och miljömässiga aspekter uppfyllas. Tyvärr finns det ringa information om rörförluster i fjärrkylasystem. Föreliggande studie fokuserar på förluster i ett fjärrkylanät genom att både använda ett R-nätverk och FEM simuleringsmodeller. Ett R-nätverksmodell bestående av termiska konduktanser har utvecklats genom analytiska ekvationer och simuleringar med FEM har utfört för validering av modellen. Därefter har ett fjärrkylanätverk som konstrueras i Gävle, analyserats. Undersökningen omfattar 15 olika rördiametrar i tre utföranden (dubbelrör med två symmetriska och en osymmetrisk värmeisolering) och i tre förläggningsdjup (0,8; 2 och 4 meter) för en säsong om 7 månader (April t o m Oktober). Särskilt utreds ökningen av temperaturen hos framledningsmediet, där matningsrören förlagts i en å mitt i staden om en sträcka av 1 km. Den maximala förlusten under säsongen, bland alla rörkonfigurationer, motsvarar 2 % av den totala levererade energin. Slutligen konstateras att kombinationen av isolerad framledningsrör och oisolerade returrör verkar som en gångbar investering, ekonomiskt och tekniskt, men kan inte användas i hela nätet eftersom stora delar har redan byggts med oisolerade plaströr. R-nätverksmodellen, som visades vara effektiv och pålitlig i undersökningen, kan som beräkningsverktyg, framförallt för dimensionering och för att uppskatta energiförluster.<br>Distribution losses are a very important factor in district energy systems. By optimizing the losses in such a system, both economical and environmental aspects can be fulfilled. Unfortunately, there is few information regarding losses for district cooling systems. This study focuses on losses in district cooling networks by using both R-network and FEM simulation models. A R-network model composed of thermal conductances has been developed through analytical equations and simulations have been performed for validation. Afterwards, an in-progress construction project of a district cooling network from the city of Gävle, Sweden, is analyzed. The assessment consists of 15 pipe diameters in three configurations (two symmetric cases and one asymmetric), at three ground laying depths (0.8, 2 and 4 meters) for a duration of 7 months (April to October). A particular case in which the main distribution pipes from and to the plant are submerged in the city’s river for a distance of 1 km is investigated in order to estimate the temperature increase of the supply water. A maximum cooling loss below 2% of the total delivered energy during the season for any network configuration resulted from the calculation. Finally, the mixed pipes array seems to be a feasible investment both economically and technically but it cannot be used for the entire network spread since a part of the network has been already built with the non-insulated plastic pipes. The R-network model proved to be effective and reliable in the analysis which provides confidence that it can serve as a solid foundation for a calculation tool - primarily for design purposes and also for estimating energy loss.
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Wu, Yin. "Power Distribution System Modeling and Simulation of an Alternative Energy Testbed Vehicle." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1289960977.

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CAMMARANO, SILVIA. "Daylighting design for energy saving in a building global energy simulation context." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2603987.

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A key factor to substantially reduce the energy consumption for electric lighting consists in a more widespread exploitation of daylight, associated with the use of the most energy efficient lighting technologies, including LEDs or electric lighting controls. At the same time daylight harvesting in indoor spaces can influence the global energy performance of a building also in terms of heating and cooling loads. For this reason, it’s always necessary to account for the balance between daylighting benefits and energy requirements. Furthermore the increasing awareness of the potential benefits of daylight has resulted in an increased need for objective information and data on the impact that different design solutions, in terms of architectural features, can have on the daylighting condition and energy demand of a space. Within this frame the research activity has been focusing on three main aspects: − Analyzing limits and potentials of the current daylighting design practice and proposing synthetic information and tools to be used by the design team during the earliest design stage to predict the daylight condition within a space. − Analyzing the effect of a proper daylighting design approach on energy requirements for electric lighting, associating with the use of efficient lighting technologies and control systems. − Assessing the influence of energy demand for electric lighting on the global energy performance. The methodology that was adopted relies on dynamic simulations carried out with Daysim and EnergyPlus used in synergy to perform a parametric study to assess the indoor daylighting conditions and the energy performance of rooms with different architectural features. Within the first phase the database of results of the lighting analysis was used to assess the sensitivity of new metrics which have been proposed by the scientific community as predictors of the dynamic variation of daylight. Furthermore it was analyzed how indoor daylight can be influenced by room’s architectural features. Than the energy demand for electric lighting for all simulated case studies have been analyzed so as to examine the influence of a proper daylighting design in presence of different lighting control systems. Finally results related to the amount of daylight available in a space were compared with annual energy demand for lighting, heating and cooling to highlight the influence of a proper daylighting design on the global energy performance.
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Kyriakodis, Georgios-Evrystheas. "Development of a coupled simulation tool for urban building energy demand, district energy systems and microclimate modeling." Thesis, La Rochelle, 2020. http://www.theses.fr/2020LAROS028.

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Ce travail de thèse aborde les liens complexes entre les processus physiques urbains, par le développement de modèles couplés pour tenir compte simultanément de la demande énergétique des bâtiments, les systèmes énergétiques individuels ou de quartier, et du microclimat urbain. L'échelle spatiale correspond aux quartiers urbains explicités géométriquement, et l’échelle temporelle est annuelle. Différentes stratégies de couplage ont été évaluées, pour leur capacité de représentation des effets thermiques, et des phénomènes couplés. Les schémas de couplages synchrones sont efficaces pour les interactions dynamiques entre bâtiments et microclimat. Néanmoins, ce couplage est sensible aux propriétés thermiques du bâtiment. La simplification de la canopée urbaine à un nœud de calcul entraîne une variation significative de la demande énergétique. Par ailleurs, le modèle développé a été utilisé pour évaluer les performances thermiques d'un quartier de La Rochelle. Le remplacement des climatiseurs individuels par un réseau urbain de froid élimine la contribution anthropique des bâtiments, et améliore le confort thermique extérieur, agissant comme une stratégie d'atténuation locale d’îlot de chaleur. Cependant, il entraîne une pénalité énergétique due aux pertes par le sol du réseau urbain. Cette pénalité énergétique est amplifiée lorsqu'une stratégie d'atténuation passive (matériaux froids) est mise en œuvre simultanément<br>This PhD work investigates the complex links between urban physical processes, through the development of coupled simulation platforms to account simultaneously for building energy demand, individual or district energy systems, and urban microclimate. The spatial and temporal scales correspond to urban neighborhoods under explicit geometries, and annual simulations respectively. Several coupling strategies have been evaluated, regarding thermal efficiency indicators, and the determination of the diversity of coupled phenomena. The synchronous coupling schemes can effectively assess the dynamical interactions between buildings and the local microclimate. Nevertheless, the coupling variable is sensitive to the thermal properties of the building. The simplification of the urban canopy layer to a single-node description reveals significant variability in building energy demand. Besides, the developed model has been employed to assess the thermal performance of an urban neighborhood in La Rochelle. The transition from local energy systems to the district energy network eliminates anthropogenic heat from buildings, and improves the outdoor thermal comfort conditions, acting as a local heat island mitigation strategy. However, it is associated with an energy penalty due to the ground losses of the piping circuit. This energy penalty is amplified when a passive mitigation strategy (cool materials) is implemented concurrently
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Heiple, Shem C. "Using Building Energy Simulation and Geospatial Modeling Techniques in Determine High Resolution Building Sector Energy Consumption Profiles." PDXScholar, 2007. https://pdxscholar.library.pdx.edu/open_access_etds/3399.

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A technique is presented for estimating hourly and seasonal energy consumption profiles in the building sector at spatial scales down to the individual taxlot or parcel. The method combines annual building energy simulations for cityspecific prototypical buildings and commonly available geospatial data in a Geographical Information System (GIS) framework. Hourly results can be extracted for any day and exported as a raster output at spatial scales as fine as an individual parcel (
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15

Liotsios, Kyriakos. "3D-Modeling and Energy Simulation of a Single Family House in Southern Greece." Thesis, KTH, Byggvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91394.

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Energy usage deriving from human activities is increasing day by day acting against the quality of the environment and the sustainable use of natural resources. The major impact of these actions is reflected on the quality of daily life. In order to face the challenge of preserving an acceptable balance between human needs and environmental status, the combination of proper design and energy simulation of buildings is the key towards smarter and more sustainable solutions. Solutions that covers a respectable percentage of the current domestic energy needs without further environmental foot printing. In the scope of this project, an existing single-family house in Southern Greece (Heraklion, Crete) is modeled using Revit ® Architecture software and then is simulated with IES® VE (plug-in) in order to give the level of energy intensity. The energy model used is fully harmonized with the new rules set by the "National Regulation for Energy Performance of Buildings - (K.En.A.K)" as it was put in force from October 2010 and onwards, and fully complies with the European Standards (EN ISO) published for the various tasks of building`s thermal performance. The structure and contents presented in this report are in full compliance with the technical directives [31, 32, 33] published by the Technical Chamber of Greece, in favour of the complex task of "Energy Certification of Buildings". The most significant capabilities of sophisticated software tools, like Revit® Architecture, IES® VE, Polysun® and PVsyst®, in favour of sustainable building design and simulation are shown throughout the whole report. Moreover, their valuable contribution is highly acknowledged by the engineers encountered with the task of studying the energy performance of existing or newly constructed buildings in Greece and issuing, the mandatory by law, "Energy Performance Certificates".
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Swedenborg, Samuel. "Modeling and Simulation of Cooling System for Fuel Cell Vehicle." Thesis, Uppsala universitet, Elektricitetslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-326070.

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This report is the result of a master’s thesis project which covers the cooling system in Volvo Cars’ fuel cell test vehicle. The purpose is to investigate if the existing cooling system in the fuel cell test vehicle works with the current fuel cell system of the vehicle, in terms of sufficient heat rejection and thus sustaining acceptable temperature levels for the fuel cell system. The project also aims to investigate if it is possible to implement a more powerful fuel cell system in the vehicle and keep the existing cooling system, with only a few necessary modifications. If improvements in the cooling system are needed, the goal is to suggest improvements on how a suitable cooling system can be accomplished. This was carried out by modeling the cooling system in the simulation software GT-Suite. Then both steady state and transient simulations were performed. It was found that the cooling system is capable of providing sufficient heat rejection for the current fuel cell system, even at demanding driving conditions up to ambient temperatures of at least 45°C. Further, for the more powerful fuel cell system the cooling system can only sustain sufficient heat rejection for less demanding driving conditions, hence it was concluded that improvements were needed. The following improvements are suggested: Increase air mass flow rate through the radiator, increase pump performance and remove the heat exchanger in the cooling system. If these improvements were combined it was found that the cooling system could sustain sufficient heat rejection, for the more powerful fuel cell system, up to the ambient temperature of 32°C.
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COSTA, MARIA LAURA MARTINS. "MODELING AND SIMULATION OF ENERGY TRANSFER IN SATURATED POROUS MEDIA VIA MIXTURE THEORY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1991. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19763@1.

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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO<br>FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO<br>O objetivo principal deste trabalho foi apresentar um modelo matemático que permitisse uma descrição local do processo de transferência de energia num escoamento saturado através de um meio poroso rígido. Este modelo teve como base o ponto de vista da Teoria de Misturas. Neste contexto, fluido e sólido (o meio poro) foram tratados como constituintes contínuos de uma mistura binária, coexistindo superpostos em todo o volume da mistura. Um importante aspecto levado em conta no presente trabalho foi permitir que os constituintes fluido e sólido possuíssem seus próprios campos de temperatura, de tal que a hipótese de equilíbrio térmico não foi suposta a priori. Problemas envolvendo convecção livre e forçada foram simulados numericamente. A transferência de calor por convecção forçada num canal poroso limitado por duas placas planas isotérmicas foi considerado em três casos diferentes. No primeiro, foram consideradas quatro condições de contorno na direção x. No segundo, a ausência de condição de contorno para o constituinte fluido na saída do canal, levou à utilização de um esquema iterativo, a única condição de contorno prescrita na direção x foi a temperatura do constituinte fluido na entrada do canal. Um trocador de calor de leito poroso num arranjo em contra-corrente também foi considerado. O trocador consistia de dois canais porosos, separados por uma parede impermeável sem resistência térmica. A convecção natural numa cavidade porosa foi também simulada, sendo considerado o efeito de alguns parâmetros adimensionais. Linhas de corrente e isotermas (para os dois constituintes) foram plotadas em alguns casos representativos.<br>The main of tis work was to present a mathematical model, suitable for a local description of energy transfer process in a saturated flow thorough a rigid porous medium. This model was constructed based upon the Theory of Mixtures viewopoint. In this context, fluid and solid (the porous medium) were treated as continuous constituents of a binary mixture, coexisting supperposed in the whole volume of the mixture. One important aspect focused on the present work was that fluid and solid constituents were allowed to hav their own temperature fields, so that no thermal equilibrium between them was supposed a priori. Forced and free convection problems were numerically simulated. The forced convection heat transfer in a porous channel bounded by two isothermal flat plates was considered in three different cases.In the first one, four boundary conditions on x-direction were considered. In the second case, the absence of boundary condition for the fluid constituent at the channels exit, led to the utilization of an iterative procedure. Finally, in the third case, in which an iterative algorithm was presented, the fluid constituent inlet temparature was the only boundary condition prescribed on x-direction. A packed-bed heat exchanger in counter-flow arrangement was alo considered. The heat exchanger consisted of two porous channels, separated by impermeable wall without thermal resistence. The natural convection flow in a porous cavity was also simulated. The effect of some dimensionless parameters was considered. Stream lines and isotherms (for both constituents) were plotted for some representative cases.
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Mead, Alex Robert. "Hardware-in-the-Loop Modeling and Simulation Methods for Daylight Systems in Buildings." Thesis, University of California, Berkeley, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10283149.

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<p> This dissertation introduces hardware-in-the-loop modeling and simulation techniques to the daylighting community, with specific application to complex fenestration systems. No such application of this class of techniques, optimally combining mathematical-modeling and physical-modeling experimentation, is known to the author previously in the literature. </p><p> Daylighting systems in buildings have a large impact on both the energy usage of a building as well as the occupant experience within a space. As such, a renewed interest has been placed on designing and constructing buildings with an emphasis on daylighting in recent times as part of the "green movement.'' </p><p> Within daylighting systems, a specific subclass of building envelope is receiving much attention: complex fenestration systems (CFSs). CFSs are unique as compared to regular fenestration systems (e.g. glazing) in the regard that they allow for non-specular transmission of daylight into a space. This non-specular nature can be leveraged by designers to "optimize'' the times of the day and the days of the year that daylight enters a space. Examples of CFSs include: Venetian blinds, woven fabric shades, and prismatic window coatings. In order to leverage the non-specular transmission properties of CFSs, however, engineering analysis techniques capable of faithfully representing the physics of these systems are needed. </p><p> Traditionally, the analysis techniques available to the daylighting community fall broadly into three classes: simplified techniques, mathematical-modeling and simulation, and physical-modeling and experimentation. Simplified techniques use "rules-of-thumb'' heuristics to provide insights for simple daylighting systems. Mathematical-modeling and simulation use complex numerical models to provide more detailed insights into system performance. Finally, physical-models can be instrumented and excited using artificial and natural light sources to provide performance insight into a daylighting system. Each class of techniques, broadly speaking however, has advantages and disadvantages with respect to the cost of execution (e.g. money, time, expertise) and the fidelity of the provided insight into the performance of the daylighting system. This varying tradeoff of cost and insight between the techniques determines which techniques are employed for which projects. </p><p> Daylighting systems with CFS components, however, when considered for simulation with respect to these traditional technique classes, defy high fidelity analysis. Simplified techniques are clearly not applicable. Mathematical-models must have great complexity in order to capture the non-specular transmission accurately, which greatly limit their applicability. This leaves physical modeling, the most costly, as the preferred method for CFS. While mathematical-modeling and simulation methods do exist, they are in general costly and and still approximations of the underlying CFS behavior. Meaning in fact, measurements of CFSs are currently the only practical method to capture the behavior of CFSs. Traditional measurements of CFSs transmission and reflection properties are conducted using an instrument called a goniophotometer and produce a measurement in the form of a Bidirectional Scatter Distribution Function (BSDF) based on the Klems Basis. This measurement must be executed for each possible state of the CFS, hence only a subset of the possible behaviors can be captured for CFSs with continuously varying configurations. In the current era of rapid prototyping (e.g. 3D printing) and automated control of buildings including daylighting systems, a new analysis technique is needed which can faithfully represent these CFSs which are being designed and constructed at an increasing rate. </p><p> Hardware-in-the-loop modeling and simulation is a perfect fit to the current need of analyzing daylighting systems with CFSs. In the proposed hardware-in-the-loop modeling and simulation approach of this dissertation, physical-models of real CFSs are excited using either natural or artificial light. The exiting luminance distribution from these CFSs is measured and used as inputs to a Radiance mathematical-model of the interior of the space, which is proposed to be lit by the CFS containing daylighting system. Hence, the components of the total daylighting and building system which are not mathematically-modeled well, the CFS, are physically excited and measured, while the components which are modeled properly, namely the interior building space, are mathematically-modeled. In order to excite and measure CFSs behavior, a novel parallel goniophotometer, referred to as the CUBE 2.0, is developed in this dissertation. The CUBE 2.0 measures the input illuminance distribution and the output luminance distribution with respect to a CFS under test. Further, the process is fully automated allowing for deployable experiments on proposed building sites, as well as in laboratory based experiments. </p><p> In this dissertation, three CFSs, two commercially available and one novel&mdash;Twitchell's Textilene 80 Black, Twitchell's Shade View Ebony, and Translucent Concrete Panels (TCP)&mdash;are simulated on the CUBE 2.0 system for daylong deployments at one minute time steps. These CFSs are assumed to be placed in the glazing space within the Reference Office Radiance model, for which horizontal illuminance on a work plane of 0.8 m height is calculated for each time step. While Shade View Ebony and TCPs are unmeasured CFSs with respect to BSDF, Textilene 80 Black has been previously measured. As such a validation of the CUBE 2.0 using the goniophotometer measured BSDF is presented, with measurement errors of the horizontal illuminance between +3% and -10%. These error levels are considered to be valid within experimental daylighting investigations. Non-validated results are also presented in full for both Shade View Ebony as well as TCP. </p><p> Concluding remarks and future directions for HWiL simulation close the dissertation.</p><p>
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Adane, Tigist Fetene. "Mapping Energy Usage in Casting Process for Cylinder Head Production : Using System Dynamic Modeling and Simulation." Thesis, KTH, Industriell produktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122459.

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Daily life of our societies is strongly linked with the usage of natural resources. However, the vital resources of our planet especially energy is a limited resource. The energy consumption in the manufacturing industry is increasing and becoming noticeable; moreover it is being consumed in ways that can’t be sustained. There is great concern about minimizing the consumption of energy usage in the manufacturing industry and sustaining the natural carrying capacity of the ecosystem as well. This is one of the important challenges in today’s industrial world. This research work looks into one of the energy intensive manufacturing processes i.e. the casting process in automotive industry. Here the casting process for cylinder head manufacturing at one of the manufacturing plant in Europe is studied for identifying the most energy intensive steps namely melting, holding and pouring. Parameters that influence these steps and the relationships for energy consumption and dissipation have also been identified through extensive literature survey. By applying system dynamics modeling and simulation approach the interaction between each parameter in the overall process is analyzed in regard to energy consumption. By varying values of the parameters that have the highest impact in the process, the breakthrough opportunities that might dramatically reduce energy consumption during melting and holding have been explored, and potentially energy-saving areas based on the findings have also been identified. The output from this research work enables the company to identify potential avenues to optimize energy usage in the production and hence sustain its manufacturing.
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20

Dhayal, Vandana Sultan Singh. "Exploring Simscape™ Modeling for Piezoelectric Sensor Based Energy Harvester." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc984261/.

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This work presents an investigation of a piezoelectric sensor based energy harvesting system, which collects energy from the surrounding environment. Increasing costs and scarcity of fossil fuels is a great concern today for supplying power to electronic devices. Furthermore, generating electricity by ordinary methods is a complicated process. Disposal of chemical batteries and cables is polluting the nature every day. Due to these reasons, research on energy harvesting from renewable resources has become mandatory in order to achieve improved methods and strategies of generating and storing electricity. Many low power devices being used in everyday life can be powered by harvesting energy from natural energy resources. Power overhead and power energy efficiency is of prime concern in electronic circuits. In this work, an energy harvester is modeled and simulated in Simscape™ for the functional analysis and comparison of achieved outcomes with previous work. Results demonstrate that the harvester produces power in the 0 μW to 100 μW range, which is an adequate amount to provide supply to low power devices. Power efficiency calculations also demonstrate that the implemented harvester is capable of generating and storing power for low power pervasive applications.
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21

Widström, Torun. "Enhanced Energy Efficiency and Preservation of Historic Buildings : Methods and Tools for Modeling." Licentiate thesis, KTH, Byggnadsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102544.

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As the environmental impacts of the energy usage of the world today becomes more and more evident, enhancement of energy performance of the already existing building stock becomes more urgent. Buildings belonging to the cultural heritage are often the ones that are most difficult to deal with in this context. The subject of this thesis is the use of building simulation of historic buildings. The task here is to identify and when necessary develop simulation tools and methods that are suitable for planning of retrofitting strategies in historic buildings, and to identify and analyze what demands such tools and methods would have to fulfill, in what contexts different simulation strategies are suitable, how the demands on the tools might be met and what results and how the results would facilitate the decision making process in the most optimal way. A powerful means to acquire such analyses is the use of whole-building simulation. In the case of historical buildings there are several aspects to take into consideration, determining the choice of simulation tool and method. This thesis includes Investigation of the variability of the demands on simulation tools and methods that the historic buildings pose, and its implication on complexity of the simulation process, and suggestion of a complexity index tool. Investigation of the whole-building simulation process and how it complies with the demands identified, and how the exergy concept can be used, exemplified by a case study. Identification of a need for a tool and method for a large amount of cases not easily covered by abundantly available tools and methods Suggestion of a tool and method to address these cases, and presentation of a case study where the suggested tool and method have been applied, with good agreement between the simulated and measured values. One important feature of the suggested tool is the Very Small Wall-part Method, that includes the assessment of especially damage prone points into the whole-building simulation model, otherwise unable to accommodate these points. Another is the damage risk assessment feature where a mould risk prediction tool is presented.<br><p>QC20120920</p>
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Fu, Chenglong. "Automation of Building Energy Performance Simulation with IDA ICE." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-284528.

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Buildings play a central role for livability and carbon footprint of urban areas. Ambitious energy saving and emission reduction targets created a need for a new generation of decisionsupport methods and tools that allow for detailed analysis of urban energy on a large scale. Urban building energy modeling (UBEM) that has emerged recently is an efficient approach to assess energy performance of multiple buildings and system effects from urban energy interventions. However, the further upscale of UBEMs is significantly limited due to the lack of automation for building energy performance (BEP) simulations required for such models in large amounts. This thesis aimed to explore challenges for automation of BEP simulations, and to develop a prototype tool that would serve as a middleware between UBEM and BEP simulation engine, focusing on the IDA ICE simulation software. The result of this thesis is icepy — a tool for automation of BEP simulations in IDA ICE. It uses IDA ICE API and Lisp scripting to provide interaction between UBEM process and IDA ICE in order to generate initial simulation model (IDM), execute simulation and manage results in an automated way. Being implemented as a Python package, it allows to modify multiple IDMs or export simulation results with a few lines of code. The developed tool has been tested and validated for the case building in Minneberg, Stockholm. The automation capabilities provided by icepy has allowed to perform sensitivity analysis for building design parameters as was demonstrated for the window-to-wall ratio (WWR) and three various algorithms for window distribution. The resulting tool has limited functionality as it addressed building envelopes which is only one component of building simulation. However, it has proved to be an efficient approach to automate simulation process and has shown a good potential for further development of such tools.<br>Byggnader spelar en central roll för urbana områdens levbarhet och koldioxidavtryck. Ambitiösa mål för energibesparing och utsläppsminskning har skapat ett behov av en ny generation beslutsstödmetoder och verktyg som möjliggör detaljerad analys av städers energianvändning i stor skala. Urban byggnadsenergimodellering (UBEM) har nyligen utvecklats och är ett effektivt tillvägagångssätt för att bedöma energiprestanda för flera byggnader och systemeffekter för olika energiåtgärder inom den urban miljön. Den ytterligare uppskalningen av UBEM är dock begränsad på grund av bristen på automation av simulering som är inriktade på byggnadsenergiprestanda (BEP), vilket krävs för att hantera stora byggnadsbestånd. Det här examensarbetet syftar till att utforska utmaningar med automatisering av BEP-simuleringar och att utveckla en prototyp som ska fungera som en mellanprogramvara mellan UBEM och BEP-simuleringsmotorer, med fokus på IDA ICE(som är en simuleringsprogramvara). Resultatet av examensarbetet är icepy, som är ett verktyg för att automatisera BEP-simuleringar i IDA-ICE. Icepy använder IDA ICE API och Lispskript för att tillhandahålla interaktion mellan UBEM-processen och IDA ICE för att generera en initial simuleringsmodell (IDM), utför själva simuleringen och slutligen hanterar resultatet på ett automatiserat sätt. Genom att icepy implementeras som ett Pythonpaket kan den modifiera flera IDM:er och även exportera simuleringsresultat med några få kodrader. Området Minneberg i Stockholm har använts i en fallstudie för att validera och testa verktyget. Automatiseringsfunktionerna i icepy har möjliggjort känslighetsanalyser för olika byggnadsdesignparametrar, exempelvis studerades påverkan av olika värden på förhållandet mellan fönster och väggar genom användning av tre olika algoritmer för fönsterdistributioner. Det utvecklade verktyget har begränsningar i funktionalitet framförallt på grund av att enbart byggnadens ytterskal studerades i byggnadsenergisimuleringarna. Verktyget har dock visat sig vara ett effektivt tillvägagångssätt för att automatisera simuleringsprocesser, vilket visar på en god potential att också vidareutveckla dessa verktyg.
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23

Patwardhan, Parag Vilas. "Modeling the elastic and plastic response of single crystals and polycrystalline aggregates." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1616.

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Understanding the elastic-plastic response of polycrystalline materials is an extremely difficult task. A polycrystalline material consists of a large number of crystals having different orientations. On its own, each crystal would deform in a specific manner. However, when it is part of a polycrystalline aggregate, the crystal has to ensure compatibility with the aggregate, which causes the response of the crystal to change. Knowing the response of a crystal enables us to view the change in orientation of the crystal when subjected to external macroscopic forces. This ability is useful in predicting the evolution of texture in a material. In addition, by predicting the response of a crystal that is part of a polycrystalline aggregate, we are able to determine the free energy of each crystal. This is useful in studying phenomena like grain growth and diffusion of atoms across high energy grain boundaries. This dissertation starts out by presenting an overview of the elastic and plastic response of single crystals. An attempt is made to incorporate a hardening law which can describe the hardening of slip systems for all FCC materials. The most commonly used theories for relating the response of single crystals to that of polycrystalline aggregates are the Taylor model and the Sachs model. A new theory is presented which attempts to encompass the Taylor as well as the Sachs Model for polycrystalline materials. All of the above features are incorporated into the software program "Crystals".
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Gkiala, Fikari Stamatia. "Modeling and Simulation of an Autonomous Hybrid Power System." Thesis, Uppsala universitet, Fasta tillståndets fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-267767.

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In this report, the modeling process and operation of an autonomous hybrid power system is studied. It is built based on a hypothetical case study of electrification of a remote village of 100 inhabitants in Kenya. The power demand is estimated and the costs of equipment components are specified after extensive research, so that the techno-economical design of the system can be carried out. The microgrid consists of photovoltaics, wind turbine, batteries, diesel genset, basic loads and water pumping and purification load. The system is modeled and simulated in terms of power management and its operation as well as the performance of the dispatch strategy is assessed. Problems like the management of extra power or tackling the deficit of power in the system are addressed. The model represents reliably the behavior of the microgrid and several improving actions are suggested.
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25

Kodieh, Alaa. "Poro-elastic numerical modeling of internal erosion : development of an energy-based approach." Thesis, Nantes, 2020. http://www.theses.fr/2020NANT4041.

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La majeure partie des instabilités observées sur les ouvrages hydrauliques en terre est due aux mécanismes d’érosion interne. Parmi ces mécanismes, la suffusion est un processus volumique qui combine le détachement, le transport et l’éventuelle filtration d’une partie des grains transportés. Dans la littérature, la cinétique de ce processus a été peu étudiée, contrairement à son initiation. Ce travail de thèse a pour objectif d’étudier le développement de la suffusion pour lequel une nouvelle loi de comportement est proposée à partir de l’approche énergétique. Cette loi utilise deux paramètres qui caractérisent la fin du processus de suffusion et un paramètre qui gouverne la vitesse de son développement. Cette loi est validée grâce à des essais expérimentaux existants et est comparée à deux autres lois issues de la littérature. Les principaux avantages de la loi basée sur l’énergie sont de limiter la masse érodée cumulée à une valeur maximale et d’utiliser des paramètres mesurables expérimentalement. Pour modéliser ce phénomène, un modèle thermoporo- élastique est développé dans le cadre de la théorie des mixtures. Le sol saturé et érodable est représenté par un mélange à deux phases et quatre espèces. La solution aux équations de champs est obtenue numériquement par la méthode des éléments finis. Les capacités du modèle sont présentées à l’échelle de l’échantillon et à l’échelle d’un modèle physique de digue. La simulation numérique de ce modèle physique montre des résultats prometteurs, en particulier pour l’ordre de grandeur de la masse érodée cumulée ainsi que la distribution spatiale des particules fines. Cette étude ouvre d’intéressantes perspectives de recherche sur la simulation d’ouvrages à partir de paramètres mesurés en laboratoire<br>Internal erosion processes are responsible for the majority of instabilities within hydraulic earth structures. Among these processes, suffusion is the volumetric process gathering detachment, transport and possibly filtration of some transported particles. In literature, the suffusion kinetics has been little tackled, unlike its initiation. This study deals with suffusion kinetics for which a new relationship inspired from the energy approach is proposed. This relationship uses two parameters that characterize the end of the suffusion process and one parameter that governs its development. This relationship is validated against existing experimental results and is compared with two other relationships inspired from the literature. The main advantages of the energy-based law are to limit the cumulative eroded mass with a cap value and to use experimentally measurable parameters. To model this phenomenon, a thermo-poro-elastic model is developed within the mixture theory framework. The saturated erodible soil is represented by a two-phase four-species mixture. Solution to the governing equations is obtained numerically using the finite element approach. Finally, the capabilities of the model are presented at both the sample scale and the scale of a physical model of dike. The numerical simulation of the dike model shows promising results, particularly for the magnitude of the cumulative eroded mass and the spatial distribution of fine particles. This study opens the way to further research opportunities concerning the simulation of earth structures based on laboratory measured parameters
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Roberts, E. C. "Energy simulation of climatic wind tunnel plant." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/7250.

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The Climatic Wind Tunnel (CWT) is a facility used by the motor industry to test vehicles under climatic extremes without the need for expensive overseas test programs. This work focuses on the application of computer simulation to the Heating Ventilation and Air Conditioning (HVAC) plant that makes up a CWT facility. The objective being to reduce its operational costs through the identification of energy saving operational strategies. When in operation the CWT has a peak power consumption of 3MW. The implementation of any measures that would reduce this peak load would give rise to considerable savings in the operating costs of the facility. Computer simulation is an accepted technique for the study of systems operating under varying load conditions. Simulation allows rapid analysis of different strategies for operating plant and the effectiveness of achieving the desired effect without compromising the buildings performance. Models for the components of the CWT have been developed and coded in Neutral Model Format. These models have then been linked together in a modular simulation environment to give a model of the complete plant. The CWT plant naturally decomposesin to four major subsystems these being the test chamber, the soakroom, air make-up and refrigeration system. Models of all the primary and secondary HVAC plant are described as is how they constitute the systems that make up the CWT. Validation tests for individual components as well as for the systems have been carried out. To illustrate the potential of the application of computer simulation into finding improved modes of operation that would reduce the energy consumption of the facility, four studies have been carried out. The studies involve the possibility of scheduling the operation of condenser fans as a function of refrigeration load and outside ambient temperature, methods for the pre-test conditioning of a vehicle, a reduction in the secondary refrigerant flow temperature and an increase in the thickness of the insulated panels from which the facility is constructed. The studies carried out showed that there was potential for moderate energy savings to be made in the operation of the facility and that extended simulation runs would allow for the in-depth assessment of a large range of possible modes of plant operation in order to identify the areas where the greatest savings are possible.
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Yao, Min. "Computed radiography system modeling, simulation and optimization." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0128/document.

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Depuis plus d’un siècle, la radiographie sur film est utilisée pour le contrôle non destructif (CND) de pièces industrielles. Avec l’introduction de méthodes numériques dans le domaine médical, la communauté du CND industriel a commencé à considérer également les techniques numériques alternatives au film. La radiographie numérique (en anglais Computed radiography -CR) utilisant les écrans photostimulables (en anglais imaging plate -IP) est une voie intéressante à la fois du point de vue coût et facilité d’implémentation. Le détecteur (IP) utilisé se rapproche du film car il est flexible et réutilisable. L’exposition de l’IP aux rayons X génère une image latente qui est ensuite lue et numérisée grâce à un système de balayage optique par laser. A basse énergie, les performances du système CR sont bonnes ce qui explique son utilisation importante dans le domaine médical. A haute énergie par contre, les performances du système CR se dégradent à la fois à cause de la mauvaise absorption de l’IP mais également de la présence de rayonnement diffusé par la pièce qui, étant d’énergie plus faible, est préférentiellement absorbée par l’IP. Les normes internationales préconisent l’utilisation d’écrans métalliques pour améliorer la réponse des systèmes CR à haute énergie. Néanmoins, la nature et l’épaisseur de ces écrans n’est pas clairement définie et la gamme des configurations possibles est large. La simulation est un outil utile pour prévoir les performances d’une expérience et déterminer les meilleures conditions opératoires. Les méthodes Monte Carlo sont communément admises comme étant les plus précises pour simuler les phénomènes de transport de rayonnement, et ainsi comprendre les phénomènes physiques en jeu. Cependant, le caractère probabiliste de ces méthodes implique des temps de calcul importants, voire prohibitifs pour des géométries complexes. Les méthodes déterministes au contraire, peuvent prendre en compte des géométries complexes avec des temps de calcul raisonnables, mais l’estimation du rayonnement diffusé est plus difficile. Dans ce travail de thèse, nous avons tout d’abord mené une étude de simulation Monte Carlo afin de comprendre le fonctionnement des IP avec écrans métalliques à haute énergie pour le contrôle de pièces de forte épaisseur. Nous avons notamment suivi le trajet des photons X mais également des électrons. Quelques comparaisons expérimentales ont pu être menées à l’ESRF (European Synchrotron Radiation Facility). Puis nous avons proposé une approche de simulation hybride, qui combine l'utilisation de codes déterministe et Monte Carlo pour simuler l'imagerie d'objets de forme complexe. Cette approche prend en compte la dégradation introduite par la diffusion des rayons X et la fluorescence dans l'IP ainsi que la diffusion des photons optiques dans l'IP. Les résultats de différentes configurations de simulation ont été comparés<br>For over a century, film-based radiography has been used as a nondestructive testing technique for industrial inspections. With the advent of digital techniques in the medical domain, the NDT community is also considering alternative digital techniques. Computed Radiography (CR) is a cost-efficient and easy-to-implement replacement technique because it uses equipment very similar to film radiography. This technology uses flexible and reusable imaging plates (IP) as a detector to generate a latent image during x-ray exposure. With an optical scanning system, the latent image can be readout and digitized resulting in a direct digital image. CR is widely used in the medical field since it provides good performance at low energies. For industrial inspection, CR application is limited by its poor response to high energy radiation and the presence of scattering phenomena. To completely replace film radiography by such a system, its performance still needs to be improved by either finding more appropriate IPs or by optimizing operating conditions. Guidelines have been addressed in international standards to ensure a good image quality supplied by CR system, where metallic screens are recommended for the case of using high energy sources. However, the type and thickness of such a screen are not clearly defined and a large panel of possible configurations does exist. Simulation is a very useful tool to predict experimental outcomes and determine the optimal operating conditions. The Monte Carlo (MC) methods are widely accepted as the most accurate method to simulate radiation transport problems. It can give insight about physical phenomena, but due to its random nature, a large amount of computational time is required, especially for simulations involving complex geometries. Deterministic methods, on the other hand, can handle easily complex geometry, and are quite efficient. However, the estimation of scattering effects is more difficult with deterministic methods. In this thesis work, we have started with a Monte Carlo simulation study in order to investigate the physical phenomena involved in IP and in metallic screens at high energies. In particular we have studied separately the behavior of X-ray photons and electrons. Some experimental comparisons have been carried out at the European Synchrotron Radiation Facility. Then, we have proposed a hybrid simulation approach, combining the use of deterministic and Monte Carlo code, for simulating the imaging of complex shapes objects. This approach takes into account degradation introduced by X-ray scattering and fluorescence inside IP, as well as optical photons scattering during readout process. Different simulation configurations have been compared
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Brinsfield, Jason. "Modeling and Simulation of Parallel D-STATCOMs with Full-Wave Rectifiers." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1209.

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In recent years, both a significant increase in electrical demand and a large influx of intermittent renewable energy sources have put a considerable stress on the nation’s electrical grid. Conventional power flow control techniques such as capacitor banks and tap-changing transformers are incapable of adequately handling the rapid fluctuations in power supply and demand that today’s grid experiences. Flexible AC Transmission System (FACTS) controllers are a practical way to compensate for such rapid power fluctuations. One type of shunt FACTS controller is the Static Synchronous Compensator (STATCOM), which uses fully controllable switches to source or sink reactive power to a point on the grid, thus reducing voltage fluctuations due to load changes. The purpose of this thesis is to model and simulate the operation of two Distribution STATCOMs (D-STATCOMs) operating on the same point on the grid. These D-STATCOMs also utilize parallel full-wave rectifiers that directly connect the ac grid to the dc capacitor of the D-STATCOMs. Parameters such as power loss, reaction time, stability, and THD are measured for several test scenarios. Results from this thesis show that two D-STATCOMs operating on the same point can be stable and effective under a wide range of conditions. This thesis also concludes that the inclusion of parallel rectifiers with the D-STATCOMs results in no performance improvement of the D-STATCOMs.
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29

Ramallo-Gonzalez, Alfonso Pablo. "Modelling, simulation and optimisation of low-energy buildings." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/14005.

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Basher, Mohamed Abul. "Modeling, simulation and numerical analysis of transient characteristics of unregulated power system networks." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26441.

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Design and operations of electrical distribution-transmission networks are analyzed mathematically, implemented numerically and validated by simulation. A dynamic model of a three node network with capacitors, inductors, load current controllers and regulators is proposed and cast in a general model of differential state-space equations in canonical form. The model is implemented via a Runge-Kutta algorithm. Realistic values of distribution systems are chosen as input and validated interactively so as to avoid instabilities and maintain reasonable characteristics. Typically cases are analyzed and the behavior of state variable is represented graphically. The software used and mode of representation aim at providing a robust environment to help power managers in their daily control of load balancing. The analysis also opens directions for the design of power distribution network.
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31

Gupta, Yashank. "Magnus Based Airborne Wind Energy Systems." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT094/document.

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Le siècle dernier a été le siècle de la révolution technologique. Les combustibles fossiles ont alimenté cette révolution technologique. Les défis auxquels notre société est confrontée, que ce soit le changement climatique ou la situation énergétique mondiale ou l’épuisement des réserves de combustibles fossiles, sont les défis les plus graves auxquels sont confrontés toutes les générations. L'énergie renouvelable est considérée comme la clé des problèmes énergétiques de notre société. De nombreuses technologies innovantes se font concurrence pour alimenter la prochaine révolution énergétique. Sources d'énergies renouvelables telles que l'énergie solaire, l'énergie éolienne, la biomasse, l'hydroélectricité, l'énergie géothermique, etc. Presque tous sont saisonniers, et sont donc des sources d'énergie discontinues et non uniformes. Ils ont également une limitation en termes de choix des sites de production et, en général, nécessitent de grandes étendues de terre pour les plantes, ce qui conduit à une faible densité de puissance par unité de surface.Néanmoins, l'énergie éolienne et solaire a beaucoup attiré l'attention au cours des dernières décennies. Cependant, pour que le monde passe complètement des énergies fossiles et de l’énergie nucléaire à l’énergie éolienne et solaire, il est nécessaire de développer de nouveaux types de systèmes capables de générer de l’énergie à moindre coût avec moins de contraintes de sélection de sites.Dans la quête de la source d'énergie pérenne. Notre société se tourne vers la communauté scientifique pour des solutions innovantes. Cette thèse est une étape vers la recherche de solutions innovantes à nos problèmes énergétiques. Les systèmes d'énergie éolienne à haute altitude (HAWE) ou plus communément appelés systèmes éoliens aéroportés (AWES) sont considérés comme la réponse aux besoins énergétiques des générations futures. L'énergie éolienne aéroportée (AWE) est un concept innovant visant à utiliser l'énergie des courants de vent à haute altitude, car les courants de vent à haute altitude sont presque uniformes dans le monde entier et AWES peut pratiquement être installé partout dans le monde. De plus, les systèmes AWE proposés nécessitent moins de matériau de structure. Ils devraient donc être beaucoup moins chers que toute autre source d’énergie disponible. AWE est donc une perspective prometteuse dans cette quête pour trouver une solution à nos problèmes énergétiques.Dans ce travail, la faisabilité des systèmes d'énergie éolienne aéroportés basés sur Magnus est explorée. Le travail présente en détail un bref historique des systèmes d'énergie éolienne aéroportés et des concepts de base nécessaires pour développer une compréhension de la technologie AWE. Il examine en détail les systèmes aéroportés basés sur Magnus et donne une perspective historique sur les machines basées sur l’effet Magnus. Il présente en détail les propriétés aérodynamiques de l’effet Magnus et présente un modèle aérodynamique pour ces systèmes. Puisque la modélisation est un aspect important de toute technologie. Ce travail présente un modèle détaillé des systèmes AWE basés sur Magnus ainsi que les algorithmes de contrôle nécessaires au fonctionnement de tels systèmes. Les courbes de puissance sont des outils couramment utilisés pour analyser les systèmes d'énergie éolienne. Ce travail présente une approche pour la conception de courbes de puissance pour les systèmes AWE afin d'analyser les capacités de production d'énergie des systèmes d'énergie éolienne aéroportés<br>Last century has been the century of the technology revolution. Fossil fuels have fueled this technology revolution. The challenges faced by our society be it the climate change or the world energy situation or the depletion of fossil fuel reserves are the most grievous challenges faced by any generation. Renewable energy is believed to be the key to energy problems of our society. There are many innovative technologies competing against each other to fuel the next energy revolution. Renewables sources of energies such as solar, wind, biomass, hydropower, geothermal etc. Though promising but due to the high economic cost and limited application they are yet to prove their mass scale applicability. Almost all of them are seasonal, hence, are discontinuous and non-uniform sources of energy. They also have a limitation in terms of choice of plant sites, and generally, require large tracts of land for plants which lead to low power density per unit area.Nonetheless, Wind and Solar energy have attracted a lot of attention in the last few decades. However, for the world to fully shift from fossil fuels and nuclear energy to Wind and Solar power, it is necessary to develop new kind of systems which can generate continuous power at a lower cost with fewer site selection constraints.In the quest to find the perennial clean source of energy. Our society is looking towards the scientific community for innovative solutions. This thesis is one such step towards finding innovative solutions to our energy problems. High altitude wind energy systems (HAWE) or more commonly known as Airborne wind energy systems (AWES) are believed to be the answer to the energy needs of the future generations. Airborne wind energy (AWE) is an innovative concept aiming at utilizing the energy of the high altitude wind currents, as high altitude wind currents are almost uniform across the globe, and AWES can be practically set-up anywhere around the world. Also, the proposed AWE systems require less structural material. Thus, they are expected to be much cheaper than any other available energy source. Therefore, AWE is a promising prospect in this quest to find a solution to our energy problems.In this work, the feasibility of Magnus-based airborne wind energy systems is explored. The work presents in detail a brief history of Airborne wind energy systems and the basic concepts needed to develop an understanding about the AWE technology. It discusses in detail Magnus-based airborne systems and gives a historical perspective on the Magnus-effect based machines. It discusses in detail the aerodynamical properties of the Magnus effect and presents an aerodynamic model for such systems. Since modeling is an important aspect of any technology. This work presents a detailed model of the Magnus-based AWE systems along with the control algorithms required for the operation of such systems. A common tool used to analyze wind-based energy systems is power curves. This work presents an approach to design power curves for AWE systems in order to analyze the power producing capabilities of Airborne wind energy systems
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32

Cao, Jun Verfasser], Christoph van [Akademischer Betreuer] [Treeck, and Vladimir [Akademischer Betreuer] Bazjanac. "Simmodel transformation middleware for modelica-based building energy modeling and simulation / Jun Cao ; Christoph Alban van Treeck, Vladimir Bazjanac." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1169754953/34.

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Cao, Jun [Verfasser], Christoph van [Akademischer Betreuer] Treeck, and Vladimir [Akademischer Betreuer] Bazjanac. "Simmodel transformation middleware for modelica-based building energy modeling and simulation / Jun Cao ; Christoph Alban van Treeck, Vladimir Bazjanac." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1169754953/34.

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34

Lynch, Matthew Earl. "Modeling, simulation, and rational design of porous solid oxide fuel cell cathodes." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45852.

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This thesis details research performed in modeling, simulation, and rational design of porous SOFC cathodes via development, extension, and use of the key tools to aid in the fundamental understanding and engineering design of cathode materials. Phenomenological modeling of triple phase boundary (TPB) reactions and surface transport on La₁₋ₓSrₓMnO₃ (LSM) was conducted, providing insight into the role of the bulk versus surface oxygen reduction pathway and the role of sheet resistance in thin-film patterned electrode measurements. In response to observation of sheet resistance deactivation, a modeling study was conducted to design thin-film patterned electrodes with respect to sheet resistance. Additionally, this thesis outlines the application of phenomenological chemical kinetics to describe and explain the performance and stability enhancements resulting from surface modification of La₁₋ₓSrₓCo₁₋yFeyO₃₋delta (LSCF) with a conformal LSM coating. The analysis was performed in close coordination with electrochemical experiments and transmission electron microscopy. Finally, the thesis describes conformal modeling of porous cathode microstructures using chemical kinetics and transport models. A novel application of conservative point defect ensembles was developed to allow simulations with complicated chemical surface kinetics to be efficiently coupled with bulk transport within the porous structure. The finite element method was employed to simulate electrochemical response conformal to sintered porous ceramic structures using actual 3D microstructural reconstructions obtained using x-ray microtomography. Mesh refinement, linear, and nonlinear reaction rate kinetics were employed to study the bulk versus surface oxygen reduction pathways and the effect of near-TPB nanostructure.
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35

Müller, Torsten. "Low Energy Ion Beam Synthesis of Si Nanocrystals for Nonvolatile Memories - Modeling and Process Simulations." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1134730784953-24537.

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Metal-Oxide-Silicon Field-Effect-Transistors with a layer of electrically isolated Si nanocrystals (NCs) embedded in the gate oxide are known to improve conventional floating gate flash memories. Data retention, program and erase speeds as well as the memory operation voltages can be substantially improved due to the discrete charge storage in the isolated Si NCs. Using ion beam synthesis, Si NCs can be fabricated along with standard CMOS processing. The optimization of the location and size of ion beam synthesized Si NCs requires a deeper understanding of the mechanisms involved, which determine (i) the built-up of Si supersaturation by high-fluence ion implantation and (ii) NC formation by phase separation. For that aim, process simulations have been conducted that address both aspects on a fundamental level and, on the other hand, are able to avoid tedious experiments. The built-up of a Si supersaturation by high-fluence ion implantation were studied using dynamic binary collision calculations with TRIDYN and have lead to a prediction of Si excess depth profiles in thin gate oxides of a remarkable quality. These simulations include in a natural manner high fluence implantation effects as target erosion by sputtering, target swelling and ion beam mixing. The second stage of ion beam synthesis is modeled with the help of a tailored kinetic Monte Carlo code that combines a detailed kinetic description of phase separation on atomic level with the required degree of abstraction that is necessary to span the timescales involved. Large ensembles of Si NCs were simulated reaching the late stages of NC formation and dissolution at simulation sizes that allowed a direct comparison with experimental studies, e.g. with electron energy loss resolved TEM investigations. These comparisons reveal a nice degree of agreement, e.g. in terms of predicted and observed precipitate morphologies for different ion fluences. However, they also point clearly onto impact of additional external influences as, e.g., the oxidation of implanted Si by absorbed humidity, which was identified with the help of these process simulations. Moreover, these simulations are utilized as a general tool to identify optimum processing regimes for a tailored Si NC formation for NC memories. It is shown that key properties for NC memories as the tunneling distance from the transistor channel to the Si NCs, the NC morphology, size and density can be adjusted accurately despite of the involved degree of self-organization. Furthermore, possible lateral electron tunneling between neighboring Si NCs is evaluated on the basis of the performed kinetic Monte Carlo simulations.
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36

Sielemann, Michael [Verfasser], and Gerhard [Akademischer Betreuer] Schmitz. "Device-oriented modeling and simulation in aircraft energy systems design / Michael Sielemann. Betreuer: Gerhard Schmitz." Hamburg-Harburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2013. http://d-nb.info/1048574148/34.

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Sielemann, Michael Verfasser], and Gerhard [Akademischer Betreuer] [Schmitz. "Device-oriented modeling and simulation in aircraft energy systems design / Michael Sielemann. Betreuer: Gerhard Schmitz." Hamburg-Harburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2013. http://nbn-resolving.de/urn:nbn:de:gbv:830-tubdok-12083.

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38

Bowlin, Oscar E. "Modeling and simulation of the free electron laser and railgun on an electric Naval surface platform." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Mar%5FBowlin.pdf.

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39

Xie, Tian. "Multi-zone modeling of Thermal Comfort and Energy Consumption of a hospital ward : a summer case study." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-7160.

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Hospital is of interest when consider its especial function. Because of the obviously different between the normal residential buildings, the requirement of hospitals’ indoor climate strictly differs from other buildings. The author starts this report by briefly stating the building construction currently. Surrounded the topic of thermal comfort and energy consumption, many suggestion and options came out in this report to develop a better condition. Firstly, the introduction of the hospital buildings requires the background of the hospital object and the purpose to this report will be stated. Secondly, the simulation tool and how to use this tool simulate our real case are introduced. Then, the summer case is investigated by this tool after the model is proved to be validated. Finally, the improvement of establishing a better indoor environment is raised and the results of improvement and conclusion can be found. The final result will show the optimal solution that discovered by this study after compared different alternatives carefully.
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40

Zhang, YuQi. "ADVANCED SYNCHRONOUS MACHINE MODELING." UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/118.

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The synchronous machine is one of the critical components of electric power systems. Modeling of synchronous machines is essential for power systems analyses. Electric machines are often interfaced with power electronic components. This work presents an advanced synchronous machine modeling, which emphasis on the modeling and simulation of systems that contain a mixture of synchronous machines and power electronic components. Such systems can be found in electric drive systems, dc power systems, renewable energy, and conventional synchronous machine excitation. Numerous models and formulations have been used to study synchronous machines in different applications. Herein, a unified derivation of the various model formulations, which support direct interface to external circuitry in a variety of scenarios, is presented. Selection of the formulation with the most suitable interface for the simulation scenario has better accuracy, fewer time steps, and less run time. Brushless excitation systems are widely used for synchronous machines. As a critical part of the system, rotating rectifiers have a significant impact on the system behavior. This work presents a numerical average-value model (AVM) for rotating rectifiers in brushless excitation systems, where the essential numerical functions are extracted from the detailed simulations and vary depending on the loading conditions. The proposed AVM can provide accurate simulations in both transient and steady states with fewer time steps and less run time compared with detailed models of such systems and that the proposed AVM can be combined with AVM models of other rectifiers in the system to reduce the overall computational cost. Furthermore, this work proposes an alternative formulation of numerical AVMs of machine-rectifier systems, which makes direct use of the natural dynamic impedance of the rectifier without introducing low-frequency approximations or algebraic loops. By using this formulation, a direct interface of the AVM is achieved with inductive circuitry on both the ac and dc sides allowing traditional voltage-in, current-out formulations of the circuitry on these sides to be used with the proposed formulation directly. This numerical AVM formulation is validated against an experimentally validated detailed model and compared with previous AVM formulations. It is demonstrated that the proposed AVM formulation accurately predicts the system's low-frequency behavior during both steady and transient states, including in cases where previous AVM formulations cannot predict accurate results. Both run times and numbers of time steps needed by the proposed AVM formulation are comparable to those of existing AVM formulations and significantly decreased compared with the detailed model.
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41

Rossi, Gianmarco. "modeling of proton exchange membrane water electrolyzer for green hydrogen production from solar energy." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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Hydrogen is considered one of the means by which to store energy coming from renewable and intermittent power sources. With the growing capacity of renewable energy sources, a storage system is required to not waste energy. PEM electrolysis provides a sustainable solution for the production of hydrogen and is well suited to couple with energy sources such as solar and wind. This work reports the development of simulation software to estimate the performance of a proton exchange membrane electrolyzer working at atmospheric or low pressure conditions connected to a solar energy source. The electrolyzer is defined from a validated reference semi-empirical model, which allows for simulating the electrochemical, thermal and H2 output flow behaviours with enough precision for engineering applications. An algorithm for a fitting procedure to characterize commercial products, and functions for power modulation have been implemented. A series of simulations have been carried on, starting from real photovoltaic data of input power, and the output values have been discussed, with particular attention to output flow rate, thermal behaviour and the cooling demand in order to preserve the operation of the electrolyzer.
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42

MacQueen, John. "The modelling and simulation of energy management control systems." Thesis, University of Strathclyde, 1997. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21355.

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This thesis is concerned with improving the integrity and applicability of building energy management systems(BEMS) simulation tools. The present work attempts to overcome certain inadequacies of contemporary simulation applications with respect to environmental control systems, by developing novel building control systems modelling schemes. These schemes are then integrated within a state-of-the-art simulation environment so that they can be employed in practice. After reviewing the existing techniques and various approaches to control systems design and appraisal,a taxonomy of building control system entities grouped in terms of logical, temporal and spatial element, is presented. This taxonomy is subsequently used to identify the models, algorithms, and features comprising a comprehensive modelling environment. Schemes for improving system integrity and applicability are presented based upon a simulation approach which treats the building fabric and associated plant sy stems as an integrated dynamic system. These schemes facilitate the modelling of advanced BEMS control structure and strategies, including: - hierarchical (systems level and zone-level) control systems; - single input, single output (SISO) and multiple input, multiple output (MIMO) systems; - advanced BEMS controller algorithms; - simulated-assisted control strategies based on advanced simulation time-step control techniques. The installation of the developed schemes within a whole building simulation environment, ESP-r, is also presented. Issues related to verification of the developed schemes are subsequently discussed. Users of control system simulation programs are identified and categorised. Typical applications of the new control modelling features are demonstrated in terms of these user groups. The applications are based on both research and consultancy projects. Finally, the future work required to increase the applicability and accuracy of building control simulation tools is elaborated in terms of the required integration with other technical subsystems and related computer-aided design tools.
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SASSONE, ALESSANDRO. "Integration-aware Modeling, Simulation and Design Techniques for Smart Electronic Systems." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2597354.

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Smart electronic systems represent a vast category of energy-autonomous and ubiquitously connected systems that incorporate analog, digital and MEMS components, combined with various kinds of sensors, actuators, energy storage devices and power sources. Smart systems generally find applications in the worldwide market for “Monitoring & Control” products and solutions, hence they are used in a broad range of sectors, including automotive, healthcare, Internet of Things, ICT, safety and security, and aerospace. In order to support such wide variety of application scenarios, smart systems integrate a multitude of functionalities, technologies, and materials. The design of smart systems is therefore a complex and major multidisciplinary challenge, as it goes beyond the design of the individual components and subsystems. New design and simulation methodologies are fundamental for exploring the design space in order to find the most efficient trade-off between performance and involved resources, and for evaluating and validating system behavior taking into account the interactions between closely coupled components of different nature. Current system level design methods must indeed accurately manage increasing system complexity and interaction effects between the environment and the system and among the components. Nevertheless, the involved components are usually described using different languages, relying on different models of computation, and need to be jointly simulated at various abstraction levels. This dissertation aims at bridging this gap focusing on novel integration-aware solutions for different aspects of a smart system: the design of digital subsystems and components, the modeling of batteries, and the power estimation of smart systems at system level of design abstraction. Although the design flow of digital components is well consolidated and highly standardized (e.g., commercial, fully automated synthesis & optimization tools, technology libraries, etc.), additional integration-aware design constraints arise due to the interaction of components of different technological domains and to the harsh environment where smart systems typically operate. This work presents a methodology for addressing these new constraints, thus enhancing the design of digital components. As a partial fulfillment of such constraints results in a global degradation of performance, the proposed methodology focuses on the effects rather than the physical sources of the constraints. This allows to move from the typical RTL to a system level of abstraction, i.e., SystemC TLM, obtaining a faster validation of the performance of digital subsystems. Energy efficiency is becoming increasingly important for self-powered smart electronic systems, as the amount of energy they can gather from the environment or accumulate in storage devices cannot be considered constant over time. Power supplies have therefore a very heterogeneous nature: depending on the application, more than one type of power source (e.g., photovoltaic cells, thermoelectric or piezoelectric energy generators) and storage device (e.g., rechargeable and non-rechargeable batteries, supercapacitors, and fuel cells) could be hosted onto the system. As a matter of fact, no single power source could provide the desired level of energy density, power density, current, and voltage to the system for all possible workloads. Batteries are being significantly used in smart electronic systems due to the their increased energy capacity, improved production process, and lower cost over the last years. However, a battery is an electrochemical device that involves complicated chemical reactions resulting in many non-idealities of its behavior. Therefore, a smart system designer has to characterize these non-idealities in order to accurately model how the battery delivers power to the system. This dissertation introduces a systematic methodology for the automatic construction of battery models from datasheet information, thus avoiding costly and time-consuming measurements of battery characteristics. This methodology allows generating models for several battery charge and discharge characteristics with tunable accuracy according to the amount of the available manufacturers’ data, and without any limitation in battery chemistry, materials, form factor, and size. Finally, this work introduces a modeling and simulation framework for the system level estimation of power end energy flows in smart systems. Current simulationor model-based design approaches do not target a smart system as a whole, but rather single domains (digital, analog, power devices, etc.), and make use of proprietary tools and pre-characterized models having fixed abstraction level and fixed semantics. The proposed methodology uses principles borrowed from the system level functional simulation of digital systems and extends them for simulating the behavior of subsystems whose functionality is to generate, convert, or store energy (e.g., power sources, voltage regulators, energy storage devices, etc.). This has been done at system level using standard open-source tools such as SystemC AMS and IP-XACT, which allow to explicitly represent current and voltage similarly to digital logic signals. The implemented approach facilitates virtual prototyping, architecture exploration, and integration validation, with high flexibility and modularity.
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44

Ezeanya, Emeka K. "System Advisor Model (SAM) Simulation Modeling of a Concentrating Solar Thermal Power Plant with Comparison to Actual Performance Data." Thesis, University of Louisiana at Lafayette, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10642898.

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<p> This thesis focused on the modeling and simulation of a 50 kW Concentrating Solar Power (CSP) plant, which is located in Crowley, Louisiana. The model was developed using System Advisor Model (SAM), which is software created by the National Renewable Energy Laboratory (NREL) for modeling and analyzing different renewable energy systems. The objective of this thesis is to develop a predictive model (using SAM) that will characterize the performance of the power plant and, thus, aid the analysis and evaluation of the plant&rsquo;s performance. The power plant is a research facility of the Solar Thermal Applied Research and Testing (START) Lab. This facility is focused on the development and deployment of renewable energy systems, exploring solar power options in Louisiana, and providing insight into solar power development across different locations. The power plant uses water as its Heat Transfer Fluid (HTF). Part of the design constraint for the model is the low temperature requirement for the power cycle (88 &deg;C&ndash;116 &deg;C). Because the basic ORC model of SAM does not support this low temperature range, a custom power cycle was modeled using the user-defined power cycle option of SAM. Other characteristics and controls of the plant were also properly defined. The model was validated by comparing its predictions with the actual plant data. This comparison showed a good correlation between the predicted results and the actual plant data. The validated model was then used to perform parametric analyses across different locations. The analyses showed that by operating the power plant at the optimal combination of solar multiple and hours of storage, we can achieve about 70% reduction in the cost of electrical energy, which is, indeed, a significant cost reduction.</p><p>
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Avon, Michael A. "Fluid Flow Through Carbon Nanotubes: A New Modeling and Simulation Approach." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1248615375.

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46

Sladkov, Andrey. "Numerical modeling of magnetic reconnection in laser-induced high energy density plasmas." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS376.

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Cette thèse est une étude numérique de la reconnexion magnétique dans les plasmas sans collision à l’aide d’un code cinétique. On peut étudier le processus de reconnexion magnétique lors d'expérience pour lesquels le plasma est créé par interaction d’un laser de puissance sur une cible solide. Durant cette thèse, nous avons inclus dans le code HECKLE les éléments permettant de rendre ces simulations plus réalistes pour les conditions lasers: les effets du tenseur complet des électrons ainsi que l’expansion super-Alfvénique du plasma. Nous avons ainsi mis en évidence le rôle du tenseur de pression pour réduire l’efficacité de la reconnexion, ainsi que les effets de température du plasma la rendant plus impulsionnelle<br>This thesis is a numerical study of the magnetic reconnection in collisionless plasmas using a kinetic code. We can study the magnetic reconnection process during experiments for which the plasma is created by interaction of a power laser on a solid target. During this thesis, we included in the HECKLE code the elements allowing to make these simulations more realistic for the laser conditions: the effects of the electron six-component pressure tensor as well as the super-Alfvénic expansion of the plasma. We have thus highlighted the role of the pressure tensor to reduce the efficiency of the reconnection, as well as the plasma temperature effects making it more impulsive
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47

Sanaboyina, Ram Mohan. "Test Plan for Real-Time Modeling & Simulation of Single Pole Switching Relays." ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/td/2215.

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A real-time simulator (RTS) with digital and analog input/output modules is used to conduct hardware-in-the-loop simulations to evaluate performance of power system equipment such as protective relays by exposing the equipment to the simulated realistic operating conditions. This work investigates the use of RTS to test relays with single-pole-switching (SPS) feature. Single-pole switching can cause misoperations due to fault arc during reclosing of the breakers. Through this investigation, a test procedure appropriate for the testing SPS relays has been developed. The test procedure includes power system modeling for real time simulation, relay test setup, and test plan. HYPERSIM real-time simulator was used to model an actual power system. Transmission lines, three-winding transformers, and induction motor were modeled with actual parameters. Models for fault arc in HYPERSIM real time simulator were developed. Test set-up for evaluating relay performance and wiring drawings for connecting relay in closed-loop to the simulator were developed.
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48

Zhao, Fei. "Agent-based modeling of commercial building stocks for energy policy and demand response analysis." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43704.

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Managing a sustainable built environment with a large number of buildings rests on the ability to assess and improve the performance of the building stock over time. Building stock models are cornerstones to the assessment of the combined impact of energy-related building interventions across different spatial and temporal scales. However, such models, particularly those accounting for both physical formulation and social behaviors of the underlying buildings, are still in their infancy. This research strives to more thoroughly examine how buildings perform aggregately in energy usage by focusing on how to tackled three major technical challenges: (1) quantifying building energy performance in an objective and scalable manner, (2) mapping building stock model space to real-world data space, and (3) quantifying and evaluating energy intervention behaviors of a building stock. This thesis hypothesizes that a new paradigm of aggregation of large-scale building stocks can lead to (1) an accurate and efficient intervention analysis model and (2) a functionally comprehensive decision support tool for building stock energy intervention analysis. Specifically, this thesis presents three methodologies. To address the first challenge, this thesis develops a normative building physical energy model that can rapidly estimate single building energy performance with respect to its design and operational characteristics. To address the second challenge, the thesis proposes a statistical procedure using regression and Markov chain Monte Carlo (MCMC) sampling techniques that inverse-estimate building parameters based on building stock energy consumption survey data. The outcomes of this statistical procedure validate the approach of using prototypical buildings for two types of intervention analysis: energy retrofit and demand response. These two cases are implemented in an agent-based modeling and simulation (ABMS) framework to tackle the third challenge. This thesis research contributes to the body of knowledge pertaining to building energy modeling beyond the single building scale. The proposed framework can be used by energy policy makers and utilities for the evaluation of energy retrofit incentives and demand-response program economics.
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Amin, Majdi Talal. "Dynamic Modeling and Verification of an Energy-Efficient Greenhouse With an Aquaponic System Using TRNSYS." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1450432214.

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50

Raddum, Alexander. "Transient Performance of Siemens SGT-750 and SGT-800 : Modeling and Simulations of Industrial Gas Turbines on Island Grids." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-171648.

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Distributed energy production in the form of renewable energy sources are expected to increase in the coming years, a consequence of this is instability of the power grids due to the stochastic nature and lack of inertia of renewable energy sources. In addition, small and local, so called island grids, are on the rise and these system may present an even higher sensitivity to frequency fluctuations. In these applications gas turbines are an attractive option owing to the quick start capabilities, flexible fuel options and reliable operation. The aim of this thesis is to evaluate the transient capabilities of the Siemens SGT-750 double shaft and SGT-800 single shaft industrial gas turbines in island grid settings, through simulations of substantial load increases in varying ambient settings. Furthermore the possibility of using hydrogen fuel as a renewable option to the standard natural gas will be evaluated. This thesis provides a model of a simple island grid for load sharing between two or three turbines. The model was tuned to real life test data for the two gas turbines considered. In order to evaluate the capabilities of the turbines simulations were run in cold (-30 oC), hot (30 oC) and ISO (15 oC) conditions, evaluating the maximum instant load increase capabilities. Case studies were also run on island grids containing two or three turbines in order to determine the frequency response in case of an event. Case A regarded a scenario in which two turbines ran on 50% of rated power and one tripped, case B regarded three turbines working on 33% of rated power and one tripped out. Lastly, the maximum load increase cases with hydrogen fuel mixes (25, 50, 75 and 100% hydrogen by volume) were considered. The results suggest that the SGT-750 and SGT-800 gas turbines are capable of handling scenarios on reasonably dimensioned power systems, with both machines capable of recovering instant load increases of over 50% of the rated power. The findings shows thats hort periods (&lt;10 s.) of allowed overfiring temperatures are necessary for the transient performance for the most extreme scenarios of high ambient temperatures and large loadincreases (around 50% of rated power). Furthermore an empirical κ-parameter, related to inertia and operational stability is discussed in order to compare GT load increase capability. The relevance of inertia and dynamic response is discussed and conceptually simulated to highlight the their role in gas turbine transient response. The hydrogen simulations, aside from the 75% case, showed little difference from natural gas in transient scenarios. The 75% hydrogen fuel consisting of high amounts ofinert gas however, rendered the turbine unable to withstand substantial load increases. The hydrogen simulation results are suggested to be accounted for by the rather simple combustion system and the energy densities of the gases.
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