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1
Bousnane, Kafiha. "Real-time power system dynamic simulation." Thesis, Durham University, 1990. http://etheses.dur.ac.uk/6623/.
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The present day digital computing resources are overburdened by the amount of calculation necessary for power system dynamic simulation. Although the hardware has improved significantly, the expansion of the interconnected systems, and the requirement for more detailed models with frequent solutions have increased the need for simulating these systems in real time. To achieve this, more effort has been devoted to developing and improving the application of numerical methods and computational techniques such as sparsity-directed approaches and network decomposition to power system dynamic studies. This project is a modest contribution towards solving this problem. It consists of applying a very efficient sparsity technique to the power system dynamic simulator under a wide range of events. The method used was first developed by Zollenkopf (^117) Following the structure of the linear equations related to power system dynamic simulator models, the original algorithm which was conceived for scalar calculation has been modified to use sets of 2 * 2 sub-matrices for both the dynamic and algebraic equations. The realisation of real-time simulators also requires the simplification of the power system models and the adoption of a few assumptions such as neglecting short time constants. Most of the network components are simulated. The generating units include synchronous generators and their local controllers, and the simulated network is composed of transmission lines and transformers with tap-changing and phase-shifting, non-linear static loads, shunt compensators and simplified protection. The simulator is capable of handling some of the severe events which occur in power systems such as islanding, island re-synchronisation and generator start-up and shut-down. To avoid the stiffness problem and ensure the numerical stability of the system at long time steps at a reasonable accuracy, the implicit trapezoidal rule is used for discretising the dynamic equations. The algebraisation of differential equations requires an iterative process. Also the non-linear network models are generally better solved by the Newton-Raphson iterative method which has an efficient quadratic rate of convergence. This has favoured the adoption of the simultaneous technique over the classical partitioned method. In this case the algebraised differential equations and the non-linear static equations are solved as one set of algebraic equations. Another way of speeding-up centralised simulators is the adoption of distributed techniques. In this case the simulated networks are subdivided into areas which are computed by a multi-task machine (Perkin Elmer PE3230). A coordinating subprogram is necessary to synchronise and control the computation of the different areas, and perform the overall solution of the system. In addition to this decomposed algorithm the developed technique is also implemented in the parallel simulator running on the Array Processor FPS 5205 attached to a Perkin Elmer PE 3230 minicomputer, and a centralised version run on the host computer. Testing these simulators on three networks under a range of events would allow for the assessment of the algorithm and the selection of the best candidate hardware structure to be used as a dedicated machine to support the dynamic simulator. The results obtained from this dynamic simulator are very impressive. Great speed-up is realised, stable solutions under very severe events are obtained showing the robustness of the system, and accurate long-term results are obtained. Therefore, the present simulator provides a realistic test bed to the Energy Management System. It can also be used for other purposes such as operator training.
2
McDonald, Christopher Ernest. "Framework for a visual energy use system." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1892.
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Botha, Cornelis Petrus. "Simulation of the human energy system / Cornelis Petrus Botha." Thesis, North-West University, 2002. http://hdl.handle.net/10394/9623.
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Preface -
Biotechnology is generally accepted to be the next economical wave of the future. In order to attain
the many benefits associated with this growing industry simulation modelling techniques have to be
implemented successfully. One of the simulations that ne' ed to be performed is that of the human
energy system.
Pharmaceutical companies are currently pouring vast amounts of capital into research regarding
simulation of bodily processes. Their aim is to develop cures, treatments, medication, etc. for major
diseases. These diseases include epidemics like diabetes, cancer, cardiovascular diseases, obesity,
stress, hypertension, etc. One of the most important driving forces behind these diseases is poor
blood sugar control.
The blood glucose system is one of the major subsystems of the complete human energy system. In
this study a simulation model and procedure for simulating blood glucose response due to various
external influences on the human body is presented.
The study is presented in two parts. The first is the development of a novel concept for quantifying
glucose energy flow into, within and out of the human energy system. The new quantification unit
is called ets (equivalent teaspoons sugar). The second part of the study is the implementation of the
ets concept in order to develop the simulation model.
Development of the ets concept -
In the first part of the study the ets concept, used for predicting glycaemic response, is developed
and presented.
The two current methods for predicting glycaemic response due to ingestion of food are discussed,
namely carbohydrate counting and the glycaemic index. Furthermore, it is shown that it is currently
incorrectly assumed that 100% of the chemical energy contained in food is available to the human
energy system after consumption. The ets concept is derived to provide a better measure of
available energy from food.
In order to verify the ets concept, two links with ets are investigated. These are the links with
insulin response prediction as well as with endurance energy expenditure. It is shown that with both
these links linear relationships provide a good approximation of empirical data. It is also shown that
individualised characterisation of different people is only dependent on a single measurable variable
for each link.
Lastly, two novel applications of the ets concept are considered. The first is a new method to use the
ets values associated with food and energy expenditure in order to calculate both short-acting and
long-acting insulin dosages for Type 1 diabetics. The second application entails a new
quantification method for describing the effects of stress and illness in terms of ets.
Development of the blood glucose simulation model -
The second part of the study presents a literature study regarding human physiology, the
development for the blood glucose simulation model as well as a verification study of the
simulation model.
Firstly, a brief overview is given for the need and motivation behind simulation is given. A
discussion on the implementation of the techniques for construction of the model is also shown. The
procedure for solving the model is then outlined.
During the literature study regarding human physiology two detailed schematic layouts are
presented and discussed. The first layout involves the complex flow pathways of energy through the
human energy system. The second layout presents a detailed discussion on the control system
involved with the glucose energy pathway.
Following the literature review the model for predicting glycaemic response is proposed. The
design of the component models used for the simulations of the internal processes are developed in
detail as well as the control strategies implemented for the control system of the simulation model.
Lastly, the simulation model is applied for glycaemic response prediction of actual test subjects and
the quality of the predictions are evaluated. The verification of the model and the procedure is
performed by comparing simulated results to measured data. Two evaluations were considered,
namely long-term and short-term trials. The quality of both are determined according to certain
evaluation criteria and it is found that the model is more than 70% accurate for long-term
simulations and more than 80% accurate for short-term simulations.
Conclusion -
In conclusion, it is shown that simplified simulation of the human energy system is not only
possible but also relatively accurate. However, in order to accomplish the simulations a simple
quantification method is required and this is provided by the ets concept developed in the first part
of this study. Some recommendations are also made for future research regarding both the ets
concept and the simulation model.
Finally, as an initial endeavour the simulation model and the ets concept proposed in this study may
provide the necessary edge for groundbreaking biotechnological discoveries.PhD (Mechanical Engineering) North-West University, Potchefstroom Campus, 2003
4
Williams, S. K. "Power system optimisation and stability studies using real-time simulation." Thesis, University of Bath, 1986. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370667.
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Weingarten, Leopold. "Physical Hybrid Model : Measurement - Experiment - Simulation." Thesis, Uppsala universitet, Fasta tillståndets fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-176412.
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A method has been developed, Physical Hybrid Model, to investigate the physical large scale electrical effects of a Battery Energy Storage System (BESS) on a distribution grid by scaling the response from a small size Research Development and Demonstration (RD&D) platform. In order to realize the model the control system of an existing RD&D platform was refurbished and stability of components ensured. The Physical Hybrid Model proceeds as follows: Data from a distribution grid are collected. A BESS cycle curve is produced based on analyzed measurements. Required BESS power and capacity in investigated grid is scaled down by factor k to that of the physical test installation of the RD&D platform. The scaled BESS cycle is sent as input to control of the battery cycling of the RD&D platform. The response from the RD&D platform is scaled – up, and used in simulation of the distribution grid to find the impact of a BESS. The model was successfully implemented on a regional distribution grid in southern Sweden.
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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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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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Garay, Rosas Ludwin. "System Simulation of Thermal Energy Storage involved Energy Transfer model in Utilizing Waste heat in District Heating system Application." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161726.
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Nowadays continuous increase of energy consumption increases the importance of replacing fossil fuels with renewable energy sources so the CO2 emissions can be reduced. To use the energy in a more efficient way is also favorable for this purpose. Thermal Energy Storage (TES) is a technology that can make use of waste heat, which means that it can help energy systems to reduce the CO2 emissions and improve the overall efficiency. In this technology an appropriate material is chosen to store the thermal energy so it can be stored for later use. The energy can be stored as sensible heat and latent heat. To achieve a high energy storage density it is convenient to use latent heat based TES. The materials used in this kind of storage system are called Phase Change Materials (PCM) and it is its ability of absorbing and releasing thermal energy during the phase change process that becomes very useful. In this thesis a simulation model for a system of thermal energy transportation has been developed. The background comes from district heating systems ability of using surplus heat from industrials and large scale power plants. The idea is to implement transportation of heat by trucks closer to the demand instead of distributing heat through very long pipes. The heat is then charged into containers that are integrated with PCM and heat exchangers. A mathematical model has been created in Matlab to simulate the system dynamics of the logistics of the thermal energy transport system. The model considers three main parameters: percentage content of PCM in the containers, annual heat demand and transport distance. How the system is affected when these three parameters varies is important to visualize. The simulation model is very useful for investigation of the economic and environmental capability of the proposed thermal energy transportation system. Simulations for different scenarios show some expected results. But there are also some findings that are more interesting, for instance how the variation of content of PCM gives irregular variation of how many truck the system requires, and its impact on the economic aspect. Results also show that cost for transporting the heat per unit of thermal energy can be much high for a small demands compared to larger demands.
9
Bouwer, Werner. "Designing a dynamic thermal and energy system simulation scheme for cross industry applications / W. Bouwer." Thesis, North-West University, 2004. http://hdl.handle.net/10394/592.
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The South African economy, which is largely based on heavy industry such as minerals
extraction and processing, is by nature very energy intensive. Based on the abundance of coal
resources, electricity in South Africa remains amongst the cheapest in the world. Whilst the
low electricity price has contributed towards a competitive position, it has also meant that our
existing electricity supply is often taken for granted. The economic and environmental
benefits of energy efficiency have been well documented. Worldwide, nations are beginning
to face up to the challenge of sustainable energy - in other words to alter the way that energy
is utilised so that social, environmental and economic aims of sustainable development are
supported.
South Africa as a developing nation recognises the need for energy efficiency, as it is the most
cost effective way of meeting the demands of sustainable development. South Africa, with its
unique economic, environmental and social challenges, stands to benefit the most from
implementing energy efficiency practices. The Energy Efficiency Strategy for South Africa
takes its mandate from the South African White Paper on Energy Policy. It is the first
consolidated governmental effort geared towards energy efficiency practices throughout
South Africa. The strategy allows for the immediate implementation of low-cost and no-cost
interventions, as well as those higher-cost measures with short payback periods. An initial
target has been set for an across sector energy efficiency improvement of 12% by 2014.
Thermal and energy system simulation is globally recognised as one of the most effective and
powerful tools to improve overall energy efficiency. However, because of the usual extreme
mathematical nature of most simulation algorithms, coupled with the historically academic
environment in which most simulation software is developed, valid perceptions exist that
system simulation is too time consuming and cumbersome. It is also commonly known that
system simulation is only effective in the hands of highly skilled operators, which are
specialists in their prospective fields. Through previous work done in the field, and the design
of a dynamic thermal and energy system simulation scheme for cross industry applications, it
was shown that system simulation has evolved to such an extent that these perceptions are not
valid any more.
The South African mining and commercial building industries are two of the major
consumers of electricity within South Africa. By improving energy efficiency practices within
the building and mining industry, large savings can be realised. An extensive investigation of
the literature showed that no general suitable computer simulation software for cross industry
mining and building thermal and energy system simulation could be found. Because the
heating, ventilation and air conditioning (HVAC) of buildings, closely relate to the ventilation
and cooling systems of mines, valuable knowledge from this field was used to identify the
requirements and specifications for the design of a new single cross industry dynamic
integrated thermal and energy system simulation tool.
VISUALQEC was designed and implemented to comply with the needs and requirements
identified. A new explicit system component model and explicit system simulation engine,
combined with a new improved simulation of mass flow through a system procedure,
suggested a marked improvement on overall simulation stability, efficiency and speed. The
commercial usability of the new simulation tool was verified for building applications by
doing an extensive building energy savings audit. The new simulation tool was further
verified by simulating the ventilation and cooling (VC) and underground pumping system of a
typical South African gold mine. Initial results proved satisfactory but, more case studies to
further verify the accuracy of the implemented cross industry thermal and energy system
simulation tool are needed. Because of the stable nature of the new VISUALQEC simulation
engine, the power of the simulation process can be further extended to the mathematical
optimisation of various system variables.
In conclusion, this study highlighted the need for new simulation procedures and system
designs for the successful implementation and creation of a single dynamic thermal and
energy system simulation tool for cross industry applications. South Africa should take full
advantage of the power of thermal and energy system simulation towards creating a more
energy efficient society.Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.
10
Van, Heerden Eugene. "Integrated simulation of building thermal performance, HVAC system and control." Thesis, University of Pretoria, 1997. http://hdl.handle.net/2263/37304.
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Practicing engineers need an integrated building, HVAC and control simulation tool for optimum
HVAC design and retrofit. Various tools are available to the researchers, but these are not appropriate
for the consulting engineer. To provide the engineer with a tool which can be used for
typical HVAC projects, new models for building, HVAC and control simulation are introduced and
integrated in a user-friendly, quick-to-use tool.
The new thermal model for buildings is based on a transfer matrix description of the heat transfer
through the building shell. It makes provision for the various heat flow paths that make up the
overall heat flow through the building structure.
The model has been extensively verified with one hundred and three case studies. These case
studies were conducted on a variety of buildings, ranging from a 4m2 bathroom, to a 7755 m2
factory building. Eight of the case studies were conducted independently in the Negev Desert in
Israel.
The thermal model is also used in a program that was custom-made for the AGREMENT Board
(certification board for the thermal performance of new low-cost housing projects). Extensions to
the standard tool were introduced to predict the potential for condensation on the various surfaces.
Standard user patterns were incorporated in the program so that all the buildings are evaluated on
the same basis.
In the second part of this study the implementation of integrated simulation is discussed. A solution
algorithm, based on the Tarjan depth first-search algorithm, was implemented. This ensures
that the minimum number of variables are identified. A quasi-Newton solution algorithm is used
to solve the resultant simultaneous equations.
Various extensions to the HVAC and control models and simulation originally suggested by Rousseau
[1] were implemented. Firstly, the steady-state models were extended by using a simplified
time-constant approach to emulate the dynamic response of the equipment. Secondly, a C02 model
for the building zone was implemented. Thirdly, the partload performance of particular equipment
was implemented.
Further extensions to the simulation tool were implemented so that energy management strategies
could be simulated. A detailed discussion of the implications of the energy management systems
was given and the benefits of using these strategies were clearly illustrated, in this study.
Finally, the simulation tool was verified by three case studies. The buildings used for the verification
ranged from a five-storeyed office and laboratory building, to a domestic dwelling. The energy
consumption and the dynamics of the HVAC systems could be predicted sufficiently accurately to
warrant the use of the tool for future building retrofit studiesThesis (PhD)--University of Pretoria, 1997.
gm2014
Mechanical and Aeronautical Engineering
unrestricted
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Zhang, Taoju. "Energy simulation for improved ventilation system in a collection of Swedish multi-family houses." Thesis, Högskolan i Gävle, Energisystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-24282.
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Building sector takes a large part of Swedish domestic energy use. Swedish government had set goal that required energy consumption should decrease by 20% in year 2020 compared to 1995. Public house companies will play an important role in the process. The work studies a typical Swedish Multi-family dwelling, built in 1960s and belonging to Älvkarlebyhus AB. These buildings were given enhanced air tightness in recent years which yielded a good result. This work focuses on improving the old ventilation system and decreasing energy consumption. Building energy simulation tool IDA ICE was used to model the object building and to examine the effectiveness of the new system. The tested energy efficiency measures include upgraded ventilation system with heat exchanger, and the installation of demand control (DCV) to the ventilation. Both energy, environmental and economic aspects are considered in the study. The result showed the total energy demand decreased 35% with renovation. Total investment for all buildings correspond to 5 760 000 SEK. New system could save 237 872 SEK/year and payback time will be 24 years.
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RODRIGUES, ADRIANO DA COSTA. "SIMULATION OF A HYBRID ENERGY GENERATION SYSTEM BASED ON SOLAR ENERGY, ETHANOL REFORMING AND HYDROGEN STORAGE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35601@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Neste trabalho é realizada a simulação de um sistema híbrido de geração de energia para pequenas comunidades, através de um simulador do sistema integrado de fornecimento de energia elétrica para consumidores sem acesso à rede de distribuição de energia elétrica desenvolvido para este fim. O simulador foi desenvolvido em Excel e Visual Basic for Applications (VBA). O sistema inicial consiste basicamente de uma unidade de células a combustível, baterias, um reformador de etanol para produção de hidrogênio, compressor, cilindros de armazenamento e painéis fotovoltaicos. A simulação foi desenvolvida aumentando-se gradativamente a quantidade dos componentes do sistema para atender à demanda de vários consumidores SIGFI45, até o limite do sistema, visando a diminuição do custo total de instalação por kWh para cada consumidor. Posteriormente foram avaliadas as características de cada equipamento (reformador de hidrogênio, célula a combustível do tipo PEM, painéis fotovoltaicos, banco de baterias de chumbo-ácido, inversor de frequência, compressor de hidrogênio) e a ampliação do sistema para atender a mais usuários. Foram analisados diferentes cenários, de acordo com o aumento do número de usuários do sistema e a demanda de energia resultante. Como resultado, a simulação do sistema ampliado atendeu a um maior número de consumidores, satisfazendo a demanda de pequenas comunidades com um custo menor para a produção de energia do que no caso com o sistema inicial.
In this current work it is realized the simulation of a hybrid energy generation system for small communities, through a simulation program of the integrated system of energy supply for offgrid costumers developed for this purpose. The simulator was developed in Excel and Visual Basic for Applications (VBA). The starting system consists of a unit of fuel cells, lead-acid batteries, ethanol reformer to produce hydrogen, compressor, storage cylinders and photovoltaic panels. The simulation was developed adding a new component when it was necessary to supply the demand of more than one customer SIGFI45, up to the limit of the system, aiming at reducing the installation cost per kWh for each consumer. Subsequently, the characteristics of each equipment (hydrogen reformer, PEM fuel cell, photovoltaic panels, battery bank, inverter, hydrogen compressor) were evaluated and the system was expanded to supply more users. Different scenarios were analyzed in accordance with the increase in the number of users of the system and the resulting energy demand. As a result, the optimization of the system has supplied a greater number of customers and it can supply energy for small communities with a lower cost for energy production than the original system.
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Liyanage, Damitha P. "Simulation, design and testing of a microprocessor controlled photovoltaic water pumping system." Thesis, University of Reading, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386751.
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Boyle, Patrick. "Energy Performance Simulation of Different Ventilation Systems in Sweden and Corresponding Compliance in the LEED Residential Rating System." Thesis, Högskolan Dalarna, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:du-34516.
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The importance of energy efficiency in the operation of the built environment is becoming increasingly important. Energy use in the building sector has exceeded both transportation and industry, while within buildings heating, ventilation, and air conditioning has the greatest share. In light of the recent pandemic forcing governments to issue quarantines and stay-at-home orders people are spending even more time indoors, this further emphasizes the importance of proper ventilation and the impacts on energy use. The purpose of this research was to perform a case study of a low environmental impact demonstration house to compare the energy performance of various ventilation strategies. The ventilation strategies varied by overall airflow rate, control strategy, and the presence of heat recovery. Performance was evaluated by establishing a model in IDA ICE, an equation-based modeling tool for the simulation of indoor thermal climate and energy use. The results showed energy savings due to demand-control with a reduction of 12.5%. Results also showed similar savings with a heat recovery system, indicating that any savings in heat loss due to heat recovery is at the expense of increased auxiliary energy. In this particular case, the benefit of upgrading to a heat recovery system from simple demand control set up is not readily apparent. Results also demonstrated trends and possible complications useful to future research plans that aim to measure real world ventilation performance, including how differences in the number and location of sensors impact the efficacy of the demand-controlled systems. A secondary aim was to observe how a newly constructed, low environmental impact home built in Sweden performs according the residential LEED energy budget. The results demonstrated that constructing a house using low impact materials with low embodied energy does not have to negatively impact energy performance, scoring extremely well in the Energy and Atmosphere category of a widely used sustainable building rating system.
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Dib, Ghady. "Thermodynamic simulation of compressed air energy storage systems." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI092.
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Le développement des énergies renouvelables pose la question du stockage de l’énergie électrique. L’utilisation du stockage par air comprimé semble une solution prometteuse dans le domaine du stockage d'énergie : elle se caractérise par une grande fiabilité, un faible impact environnemental et une remarquable densité énergétique stockée (kWh/m3). Jusqu’à présent, l'air comprimé a été utilisé dans de nombreux domaines comme vecteur d’énergie pour stocker différentes formes d'énergies (transport routier, poste pneumatique, plongée sous-marine). Néanmoins, actuellement de nombreux chercheurs se concentrent sur le développement de stockage d'énergie par air comprimé (CAES) à petite échelle couplé à une application de bâtiment en se basant sur les travaux développés pour les multiples systèmes de CAES à grande échelle installés dans le monde. Un modèle numérique global du système de stockage par air comprimé à petite échelle, couplé à un modèle de bâtiment et à des modules d’énergie renouvelable a été développé dans le but de modéliser différents compresseurs/détendeurs et structures d’installation développés par plusieurs startups (LightSail Energy et Enairys Powertech) et chercheurs. Les compresseurs et détendeurs adiabatiques ont d’abord été sélectionnés pour étudier le système de trigénération de stockage d'énergie par air comprimé adiabatique avancé (AA-CAES) couplé au bâtiment et aux réseaux avec les différents scénarios décrits ci-dessus. Les compresseurs et détendeurs quasi-isothermes développés par LightSail Energy et Enairys Powertech ont été modélisés pour chaque phase de la compression et de la détente. Ces modèles analytiques ont permis une meilleure compréhension du fonctionnement principal de ces technologies et d'avoir l’ordre de grandeur de différents paramètres physiques. Les systèmes I-CAES et AA-CAES sont comparés d'un point de vue financier en se référant à une analyse du marché des systèmes de production/utilisation de l'air comprimé. Trois prototypes différents ont été étudiés: deux systèmes AA-CAES (idéal et virtuel (basés sur des unités commerciales trouvées sur le marché de l'air comprimé)) et un système I-CAES (basé sur le prototype LightSail Energy CAES)In the context of developing renewable energies, storing energy improves energy efficiency and promotes the insertion of intermittent renewable energies. It consists of accumulating energy for later use in a place that may be the same or different from the place of production. Converting electrical energy to high-pressure air seems a promising solution in the energy storage field: it is characterized by a high reliability, low environmental impact and a remarkable stored energy density (kWh/m3). Currently, many researchers are focusing on developing small scale of the compressed air energy storage system (CAES) coupled to a building applications based on the work done for multiple large scale CAES systems installed in the world. A global numerical model of trigeneration CAES system coupled to a building model and renewable energy modules was developed in order to analyze the CAES system behavior responding to electrical, hot and cold energy building demand. Different energy scenarios (autonomous and connected to the grid modes), geographical locations and building typologies were proposed and analyzed. The CAES numerical model development is based on solving energy and heat transfer equations for each system component (compressor/expander, heat exchanger, high pressure air reservoir, thermal water storage tank). Adiabatic compressor and expander were firstly selected to investigate the trigeneration advanced adiabatic compressed air energy system (AA-CAES) coupled to the building and to grids with the different scenarios described above. Similar to adiabatic components, quasi-isothermal compressor and expander developed by LightSail Energy and Enairys Powertech were also analyzed by solving the energy and heat transfer equations for each phase of the compression and expansion processes. These analytical models allowed us to have a better understanding of these technologies operations and to have several orders of magnitudes of different physical parameters. I-CAES and AA-CAES were also compared from a financial point of view based on compressed air market analysis. Three different prototypes were studied: Two AA-CAES systems (ideal and virtual (some of which are based on commercial units found in the compressed air market)) and one I-CAES system (based on LightSail Energy CAES prototype)
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Sarban, Singh Ranjit Singh. "A design scheme of energy management, control, optimisation system for hybrid solar-wind and battery energy storages system." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/13788.
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Hybrid renewable energy system was introduced to improve the individual renewable energy power system’s productivity and operation-ability. This circumstance has led towards an extensive technological study and analysis on the hybrid renewable energy system. The extensive technological study is conducted using many different approaches, but in this research the linear programming, artificial intelligence and smart grid approaches are studied. This thesis proposed a complete hardware system development, implementation and construction of real-time DC Hybrid Renewable Energy System for solar-wind-battery energy source integrated with grid network support. The proposed real-time DC HRES hardware system adopts the hybrid renewable energy system concept which is composed of solar photovoltaic, wind energy system, battery energy storage system and grid network support. The real-time DC HRES hardware system research work is divided into three stages. Stage 1 involves modelling and simulation of the proposed system using MATLAB Simulink/Stateflow software. During this stage, system’s methodological design and development is emphasised. The obtained results are considered as fundamental finding to design, develop, integrate, implement and construct the real-time DC HRES hardware system. Stage II is designing and developing the electronic circuits for the real-time DC HRES hardware system using PROTEUS software. Real time simulation is performed on the electronic circuits to study and analyse the circuit’s behaviour. This stage also involves embedded software application development for the microcontroller PIC16F877A. Thus, continuous dynamic decision-making algorithm is developed and incorporated into microcontroller PIC16F877A. Next, electronic circuits and continuous dynamic decision-making algorithm are integrated with the microcontroller PIC16F877A as a real-time DC HRES hardware system to perform real time simulation. The real-time DC HRES hardware system simulation results are studied, analysed and compared with the results obtained in Stage 1. Any indifference between the obtained results in Stage 1 and Stage 2 are analysed and necessary changes are made. Stage 3 involves integrating, implementation and construction of real-time DC HRES. The continuous dynamic decision-making algorithm is also incorporated into the real microcontroller PCI16F877A development board. Real-time DC HRES’s experimental results have successfully demonstrated the system’s ability to perform supervision, coordination, management and control of all the available energy sources with lease dependency on the grid network. The obtained results demonstrated the energy management and optimisation of the available energy sources as primary power source deliver.
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Saiju, Rajesh [Verfasser]. "Hybrid Power System Modelling - Simulation and Energy Management Unit Development / Rajesh Saiju." Kassel : Universitätsbibliothek Kassel, 2008. http://d-nb.info/1000014738/34.
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McCulley, Matthew C. "Design, simulation, and preliminary testing of a 20 ampere energy management system." Thesis, Monterey, California: Naval Postgraduate School, 2015. http://hdl.handle.net/10945/45902.
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Approved for public release; distribution is unlimitedThe Department of the Navy is determined to find ways to increase the energy security of shore facilities. This is critical to ensure that facilities can meet fleet needs during a national crisis. An Energy Management System (EMS) using power electronics could be an important piece of this puzzle. In this thesis, a 20-ampere (A)-rated EMS module is designed and constructed that can be used for demonstrations and field testing. The prototype is used to conduct preliminary testing of the EMS over-current trip circuit. This thesis discusses the analog and digital redesigns that are needed to overcome the electromagnetic interference from the switching currents of the power modules that leak into the control circuitry. Finally, a Simulink model is designed to simulate the expected output from the H-bridge portion of the EMS. This model is tested and verified using measurements from the actual EMS prototype in the laboratory.
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McCartney, Shauna. "The simulation and control of a grid-connected wind energy conversion system." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4680.
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With the rising cost of petroleum, concerns about exhausting the fossil fuels we depend on for energy, and the subsequent impacts that the burning of these types of fuels have on the environment, countries around the world are paying close attention to the development of renewable types of energy. Consequently, researchers have been trying to develop ways to take advantage of different types of clean and renewable energy sources. Wind energy production, in particular, has been growing at an increasingly rapid rate, and will continue to do so in the future. In fact, it has become an integral part in supplying our future energy needs, making further advancements in the field exceedingly critical. A 2 MW wind energy conversion system (WECS) is presented and has been simulated via the dynamic simulation software Simulink. This WECS consists of a 2 MW permanent magnet synchronous generator connected to the transmission grid through a power conversion scheme. The topology of this converter system consists of a passive AC/DC rectifier as well as a PWM DC/AC IGBT inverter, used to interface the DC link with the grid. The inverter has an integrated current control system for power factor correction to improve output power stability. The described WECS enhances grid-side tolerance by buffering wind power disturbances demonstrated by its capability to isolate the grid from wind speed fluctuations. It also optimizes wind energy capture through harmonic filtering, enhancing output power quality. These findings have the potential to lead to further advancements including the capability for island operation and integration to a smart grid.ID: 029050708; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.E.E.)--University of Central Florida, 2010.; Includes bibliographical references (p. 66-70).
M.S.E.E.
Masters
Department of Electrical Engineering and Computer Science
Engineering and Computer Science
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El-Samadony, Yasser Abdel Fattah. "Simulation of liquid desiccant regeneration for an energy efficient air conditioning system." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441236.
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Li, Dingyi. "Real-time simulation of shipboard power system and energy storage device management." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/17857.
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Master of ScienceDepartment of Electrical and Computer Engineering
Noel Schulz
Many situations can cause a fault on a shipboard power system, especially in naval battleships. Batteries and ultra-capacitors are simulated to be backup energy storage devices (ESDs) to power the shipboard power system when an outage or damage occurs. Because ESDs have advantages such as guaranteed load leveling, good transient operation, and energy recovery during braking operation, they are commonly used for electrical ship applications. To fulfill these requirements, an energy management subsystem (EMS) with a specific control algorithm must connect ESDs to the dc link of the motor drive system. In this research, the real-time simulation of shipboard power system (SPS), bidirectional DC-DC converter, EMS, and ESDs are designed, implemented, and controlled on OPAL-RT system to test SPS survivability and ESD performance in various speed operations.
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Dießel, Dominic, Garth Bryans, Louis Verdegem, and Hubertus Murrenhoff. "System Analysis for Hydrostatic Transmission for Wave Energy Applications - Simulation and Validation." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200580.
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Wave Energy Converters (WEC) are used to transform energy stored in ocean waves into electrical energy. One type of WECs consists of buoyant bodies. To extract energy from their motion, hydraulic cylinders can be used to generate hydraulic power. For conversion into electric power various systems have been analysed in literature. However, the focus was put on efficiency and rigorous analyses of the system behaviour are still missing. In this paper an exemplary system consisting of two hydraulic cylinders, switchable check valves, accumulators and three motor-generator sets is analysed with help of simulation and measurement. This exemplary system is called WavePOD and was installed at the Institute for Fluid Power Drives and Controls (IFAS) of RWTH Aachen University together with Aquamarine Power and Bosch Rexroth for testing. In this paper the data collected during various test phases is used for system analysis and for validating the simulation. The simulation model is presented. The system’s response to various switching operations is investigated. Comparing the simulation with measurements validates the system`s dynamic model.
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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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Jose, Panangat James. "Simulation Validation with Real Measurements of an Intelligent Home Energy Management System." Thesis, Högskolan Dalarna, Energiteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:du-37214.
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This thesis's main objective is to conduct a comparison study between measured values and simulated results of a demonstrator, of the intelligent home energy management (iHEM) project. The comparison helps to validate the simulation. TRNSYS software is used for the design. In this study, only the thermal energy side of the project is considered. In which system-level (both domestic hot water (DHW), space heating (SH)) and component level (solar collector, gas boiler) are considered as the parameters to compare. An attempt is made to optimize both system-level and component-level simulation outputs with measured values by adopting measured boundary conditions as simulation inputs.During the comparison, the DHW loop simulation design is modified. The measured data were given as input files for simulation, replacing the estimated values used before. This is done to optimize the simulation output with measured data. In the space heating loop (SH), the simulated building model’s parameters were changed to optimize the SH demand. After the system-level validation and optimization, the component level comparison is carried out. For this, the simulation output of solar thermal collectors and gas boiler are compared with measured values. The solar collector loop in the simulation is modified to optimize the simulated results. The seasonal and yearly efficiencies of the collector have been calculated. Solar supply fraction and gas boiler supply fraction is also determined. For the comparison, graphs are plotted for three different weeks, representing the spring, summer, and winter months of 2018.The final optimized simulation output of DHW demand is 7% less than the measured value. Even after optimizing the Space heating loop (SH), the simulated building demand is 17% more heat than the demonstrator building. The simulation's solar collector output is optimized close to the measured values. The simulated gas boiler produces 19% more than the demonstrator system to meet excess SH demand in the simulation (including losses). The overall yearly collector efficiency calculated for measured and simulated values are 58% and 50%, respectively. The estimated solar collector supply fraction and gas bo
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Cabra, Henry. "Design, Simulation, Prototype, and Testing of a Notched Blade Energy Generation System." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/4992.
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This dissertation addresses the design, simulation, prototype, and test of a new energy generation system, which transforms rotational motion into electricity by the use of an innovative turbine-generator. The system is divided in two assembled subsystems that interact to finally transform kinetic energy into electricity. The first subsystem is a miniaturized notched impulse turbine system, and the second one is a millimeter permanent magnet generator (PMG) assembled into the turbine.
The conversion of biomechanical energy to electric energy, using clean and free energy produced by a living organism, is being increasingly researched [1]-[11]. These are all viable options, but advantages and disadvantages of each type of energy conversions should be evaluated individually to determine key factors such as efficiency as an energy harvesting method, the implementation cost, size, and the final applications where they will be used.
Through this dissertation, a new option of green energy conversion is made available; focusing on the use of turbines to extract energy from microfluidics, with diverse application in biomedical, military/aerospace, and home areas. These systems have the potential of converting mechanical movement energy, and hydraulic energy into electric energy that may be sufficient for self-powering nano/micro devices and nano/micro systems. A flow, with constant pressure, a magnetic generator, and a novel impulse turbine design are combined to form a self-contained miniaturized generator system. The turbine consists of two main parts: a bearingless rotor and the enclosure or casing; while the miniaturized magnetic generator is a permanent magnet brushless machine, consisting of permanent magnets in a ring configuration and radial coils. A permanent pressure, from microfluidic pressure system, is the force used to move the blades. This rotational motion of the turbine is transformed into electricity using magnetic induction, formed by permanent magnets on the rotor and nine coils fixed in the holder of the turbine. The electricity is generated when the magnetic field rotates and moves past the conductor, which induces a current according to Faraday's Law [1-3]. The system has potential uses not only in medical equipment, but in automotive applications, home appliances, and aquatic and ventilation systems.
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Cordeiro, Roberto. "Energy Storage System for Wind-Diesel Power System in Remote Locations." Thesis, Högskolan i Gävle, Energisystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-22534.
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The aim of this thesis is to show how much fuel can be saved in a power system based in diesel generators with integrated wind turbine (WDPS – Wind Diesel Power System) when a storage system is integrated. Diesel generator is still the most used power system for remote locations where the conventional grid doesn’t reach and its integration with wind turbine is seen as a natural combination to reduce diesel consumption. However, the wind intermittency brings some challenges that might prevent the necessary diesel savings to the level that justifies the integration with wind turbine. The introduction of a storage system can leverage the wind energy that would otherwise be wasted and use it during periods of high demand.The thesis starts by describing the characteristics of energy storage systems (ESS) and introducing the major ESS technologies: Flywheel, Pumped Hydro, Compressed Air and the four main battery technologies, Lead Acid, Nickel-Based, Lithium-ion and Sodium-Sulphur. The aim of this step it to obtain and compile major ESS parameters to frame then into a chart that will be used as a comparison tool.In the next step, wind-diesel power systems are described and the concept of Wind Penetration is introduced. The ratio between the wind capacity and diesel capacity determines if the wind penetration is low, medium and high and this level has a direct relation to the WDPS complexity. This step also introduces important concepts pertaining to grid load and how they are affected by the wind penetration.Next step shows the development of models for low, medium and high penetration WDPS with and without integrated ESS. Simulations are executed based on these models in order to determine the diesel consumption for each of them. The simulations are done by using reMIND tool.The final step is a comparative study where the most appropriated ESS technology is chosen based on adequacy to the system, system size and location. Once the technology is chosen, the ESS economic viability is determine based on the diesel savings obtained in the previous step.Since this is a general demonstration, no specific data about wind variation and consumer demand was used. The wind variation, which is used as the input for the wind turbine (WT), was obtained from a typical Weibull Distribution which is the kind of distribution that most approximate a wind pattern for long term data collection. The wind variation over time was then randomly generated from this distribution. The consumer load variation is based on a typical residential load curves. Although the load curve was generated randomly, its shape was maintained in conformity with the typical curves.This thesis has demonstrated that ESS integrated to WDPS can actually bring a reasonable reduction in diesel utilization. Even with a wind pattern with a low mean speed (5.31 m/s), the savings obtained was around of 17%.Among all ESS technologies studied, only Battery Energy Storage System (BESS) showed to be a viable technology for a small capacity WDPS. Among the four BESS technologies studied, Lead-Acid presents the highest diesel savings with the lower initial investment and shorter payback time.O objetivo dessa tese é determinar quanto combustível pode ser economizado quando se integra um sistema de armazenamento de energia (ESS na sigla em Inglês) a um sistema gerador baseado em gerador diesel integrado com turbina eólica (WDPS na sigla em Inglês). Geradores à diesel são largamente utilizados em áreas remotas onde a rede de distribuição de eletricidade não chega, e a integração de geradores à diesel com turbinas eólicas se tornou a combinação usual visando a economia de combustível. No entanto, a intermitência do vento cria alguns desafios que podem inclusive tornar essa integração inviável economicamente. A introdução de ESS à esse sistema visa o aproveitamento da energia que seria desperdiçada para usá-la em periodos de alta demanda.A tese começa descrevendo as características de ESS e suas principais tecnologias: Flyweel, hidroelétrica de bombeamento, ar-comprimido e as quatro principais tecnologias de bateria, Chumbo-Ácido, Níquel, Íon de Lítio e Sódio-Sulfúrico. O objetivo dessa etapa é obter os principais parâmetros de ESS e apresentá-los numa planilha para referência futura.Na etapa seguinte, geradores à diesel são descritos e é introduzido o conceito de Penetração do Vento. A razão entre a capacidade eólica e a capacidade do gerador diesel determina se a penetração é baixa, média ou alta, e esse nível tem uma relação direta com a complexidade do WDPS. Nessa etapa também são introduzidos importantes conceitos sobre demanda numa rede de distribuição de eletricidade e como esta é afetada pela penetração do vento.A etapa seguinte apresenta a modelagem de WDPS com baixa, média e alta penetração, incluindo a integração com ESS. Sobre esses modelos são então executadas simulações buscando determinar o consumo de diesel de cada um. As simulações são feitas usando a ferramenta reMIND.A última etapa é um estudo comparativo para determinar qual tecnologia de ESS é a mais apropriada para WDPS, levando-se em conta sua localização geográfica e capacidade. Uma vez que a escolha tenha sido feita, a viabilidade econômica do ESS é calculada baseado na ecomonia de combustível obtida na etepa anterior.Como esta tese apresenta uma demonstração, não foram utilizados dados reais de variação do vento nem de consumo. A variação do vento foi obtida de uma distribuição Weibull típica, que é a distribuição que mais se aproxima da característica do vento coletada em logo prazo. A variação do vento no tempo foi gerada aleatoriamente baseada nessa distribuição. A curva de consumo é baseada em curvas de consumo residenciais típicas. Embora a curva de consumo tenha sido gerada aleatoriamente, o seu formato foi mantido em conformidade com as curvas típicas.Essa tese demonstrou que ESS integrado à WDPS pode trazer uma economia razoável. Mesmo usando uma distribuição de vento com baixo valor médio (5.3 m/s), a economia obtida foi de 17%.Dentre as tecnologias de ESS pesquisadas, apenas o sistema de armazenamento com bateria (BESS na sigla em Inglês) se mostrou viável para um WDPS com pequena capacidade. Dentre as quatro tecnologias de BESS pesquisadas, Chumbo-Ácido foi a que apresentou a maior economia de diesel com o menor investimento inicial e com o menor tempo de retorno do investimento.
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Rautenbach, John White. "Article: Reducing the electricity cost of a three-pipe water pumping system : a case study using software / White Rautenbach." Thesis, North-West University, 2004. http://hdl.handle.net/10394/74.
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Efficient control is often the most cost-effective option to improve on the running cost
of a Three-Pipe Water Pumping System. However, the effect of changing the control
strategy (i.e. on energy consumption) is usually difficult to predict. To obtain this
information more easily, a new simulation tool, QUICKcontrol, was developed. This
new tool was used to investigate the energy cost savings potential in a Three-Pipe
Water Pumping System. The influence of pump scheduling, dam level set points,
control parameters and different combinations thereof was investigated. The
simulation models were firstly verified with measurements obtained from the existing
system to confirm their accuracy for realistic control retrofit simulations. With the aid
of the integrated simulation tool it was possible to predict savings of R 195'000 per year with an average 3.8 MW of load shifted.Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.
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Tahan, Niloofar. "Energy assessment of a cold store by dynamic simulation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
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Nowadays, the world of construction underwent a major revolution. Buildings are responsible for more than 40% of global energy consumption. Awareness of the energy performance of the building and its operation are critical steps toward sustainable development. To design a sustainable building, the total energy requirements of the building should be kept to a minimum. None of this is possible without proper building architectural design. As a result, to achieve the building with desired quality and standard, all aspects should be taken into practice at all stages of design and construction.
Energy consumption is assessed using different methods to precast a behavior of a building’s energy consumption. Many factors should be considered while designing an energy-efficient building. Therefore, computer simulation is used to simulation processes.
In this project, DesignBuilder has been used to design and simulate the performance of the cold store. In the design phase, building materials for each structural part of this cold store are defined in the software. Also, by defining two different insulators (PIR/PUR Polyurethane), there is a possibility to compare them, and it can be concluded that PIR Polyurethane has a better performance than PUR Polyurethane.
In addition, by defining various parameters such as lighting, the number of people and the time of their presence, and definition of HVAC system, the simulation can be performed. We concluded that to have the desired temperature, a heating system should also be designed for winter, therefore a heating system is defined and its schedule adjusted for the seasons when the zone air temperature becomes less than 5 °C.
Finally, by defining all the parameters and systems, the simulation was performed for a period of one year. As a result, the amount of annual energy required is calculated. By comparing the results obtained by two different insulation, we conclude that PIR Polyurethane insulation has a better result.
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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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Henchman, Richard Humfry. "Simulation studies of the structure and energetics of a host-guest system." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302351.
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ZHANG, YAOYUN. "Building energy system simulation : A case study renovation of an apartment located in Gävle Sweden." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-18847.
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Maggiore, Pierpaolo. "Energy retrofit of an office building in Stockholm: energy performance analysis of the cooling system." Thesis, KTH, Installations- och energisystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190960.
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The increasing attention towards energy efficiency issues has triggered an important process involving the renovation of existing buildings and, at the same time, the creation of recognized certifications assuring the quality of the projects. In line with this trend, the Sweco headquarters, an office building characterized by 24700 m2 of floor area and located in Stockholm, was totally retrofitted in 2012 and obtained the Gold rating after being assessed with the Miljöbyggnad certification procedure. The HVAC system was a key element of the retrofit project since one of the final aims was to combine high indoor environment standards with efficient system performances. However, even if the quality of the design is certified, it is possible that, under real operating conditions, complex systems behave differently from the expectations and adjustments are necessary to correct the emerged gap. To achieve this goal, it is essential to identify the points of weakness of the system by carrying out an energy performance analysis, which is the core of this project. In fact, after providing an overview of the building and the retrofit, this work focuses on the analysis of the cooling system installed in the Sweco building and proves the importance of adopting a step-by-step approach to the problem. Therefore, an increasing level of detail characterizes each step of the analysis, whose final aim is to highlight potential aspects to be improved and create a baseline to test possible solutions.SIRen
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Alghamdi, Jamal Khaled. "CFD Simulation Methodology for Ground-Coupled Ventilation System." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35736.
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In the past two decades, a growing interest in alternative energy resources as a
replacement to the non-renewable resources used now days. These alternatives include
geothermal energy which can be used to generate power and reduce the demands on
energy used to heat and cool buildings. Ground-coupled ventilation system is one of the
many applications of the geothermal energy that have a lot of attention in the early 80â s
and 90â s but all designs of the system where based on single case situations. On the other
hand, computational fluid dynamics tools are used to simulate heat and fluid flow in any
real life situation. They start to develop rapidly with the fast development of computers
and processors. These tools provide a great opportunity to simulate and predict the
outcome of most problems with minimum loss and better way to develop new designs.
By using these CFD tools in GCV systems designing procedure, energy can be conserved
and designs going to be improved.
The main objective of this study is to find and develop a CFD modeling strategy
for GCV systems. To accomplish this objective, a case study must be selected, a proper
CFD tool chosen, modeling and meshing method determined, and finally running
simulations and analyzing results. All factors that affect the performance of GCV should
be taken under consideration in that process such as soil, backfill, and pipes thermal
properties. Multiple methods of simulation were proposed and compared to determine the
best modeling approach.Master of Science
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PRADERE, GUILLAUME LOUIS. "PERFORMANCE SIMULATION OF A THERMOELECTRIC PLANT PREHEATING DIESEL ENGINE SYSTEM VIA SOLAR ENERGY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=31824@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Este trabalho tem por objetivo principal a avaliação de desempenho de um sistema piloto de preaquecimento dos motores da central termelétrica Gera Maranhão, via energia solar térmica, em Miranda do Norte, Maranhão, através de uma simulação numérica. Cinco subsistemas independentes, cada um responsável pelo preaquecimento de um motor Wartsila 20V32 de 8,73 MW, foram construídos, somando um total de 500 coletores solares instalados e uma superfície de captação solar total de 1000 metros quadrados. Uma estação meteorológica com sensores de radiação solar global, difusa, direta e temperatura ambiente foi posicionada do lado dos sistemas para medir as condições ambientais na região. A simulação do desempenho do sistema solar foi efetuada ao longo de um ano com dados de radiação solar da estação meteorológica de Buriticupu, no Maranhão, dados que mais se aproximam dos dados disponíveis de Miranda do Norte. Correlações para transformar a radiação global medida numa superfície horizontal para uma superfície inclinada foram selecionadas após uma revisão bibliográfica dentre as disponíveis na literatura. Diferentes cenários de controle do acionamento das bombas de água foram comparados a fim de determinar a melhor configuração de operação. A influência da temperatura de preaquecimento dos motores no desempenho do sistema solar foi avaliada também. Os resultados da simulação foram comparados com os resultados obtidos via o método F-CHART. Uma participação média anual da energia solar de 11,5 por cento foi encontrada para o preaquecimento dos motores levando a uma redução de 24693 kg/ano de óleo combustível usado na caldeira do sistema de preaquecimento dos motores da usina termelétrica.
The present work has as main objective the performance evaluation of a pilot system for preheating the engines of Gera Maranhão power plant, in Miranda do Norte, state of Maranhão, via thermal solar energy using a numerical simulation. Five independent subsystems, each one responsible for the preheating of a Wartsila 20V32 internal combustion engine of 8.73 MW, were installed. These systems amount five hundred solar collectors, with a total solar collecting area of 1000 square meters. A meteorological station with sensors for global, diffusive and beam solar radiation, as well as ambient temperature recorders, was placed by the side of the system in mode to measure ambient condition in the area. The simulation of the solar system performance was processed over a year with data of solar radiation for a meteorological station of Buriticupu, state of Maranhão, Brazil. Correlations to transform the global radiation measured on a horizontal plane to a sloped plane were selected, following a selection from a literature review. For the control of the water pumps, different scenarios were compared in order to determine the best operational configuration. The influence of engine preheating temperature in the performance of the solar system was also evaluated. Simulation results were compared with results obtained with the F-CHART method. An annual average solar energy contribution of 11.5 percent was found for the preheating of the engines. This resulted in a reduction of 24693 kg per year of fuel oil used in the boiler of the traditional preheating system of the power plant.
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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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Rau, de Almeida Callou Gustavo. "Energy consumption and execution time estimation of embedded system applications." Universidade Federal de Pernambuco, 2009. https://repositorio.ufpe.br/handle/123456789/1877.
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Previous issue date: 2009Nos últimos anos, a redução do consumo de energia das aplicações dos sistemas embarcados tem recebido uma grande atenção da comunidade científica, visto que, como o tempo de resposta e o baixo consumo de energia são requisitos conflitantes, esses estudos tornam-se altamente necessários. Nesse contexto, é proposta uma metodologia aplicada nas fases iniciais de projeto para dar suporte às decisões relativas ao consumo de energia e ao desempenho das aplicações desses dispositivos embarcados. Al´em disso, esse trabalho propõe modelos temporizados de eventos discretos que são avaliados através de uma metodologia de simulção estocástica com o objetivo de representar diferentes cenários dos sistemas com facilidade. Dessa forma, para cada cenário ´e preciso decidir o n´umero máximo de simulações e o tamanho de cada rodada da simulação, onde ambos os fatores podem impactar no desempenho para se obter tais estimativas. Essa metodologia considera também, um modelo intermediário que representa a descrição do comportamento do sistema e, é através desse modelo que cenários são analisados. Esse modelo intermediário ´e baseado em redes de Petri coloridas temporizadas que permitem não somente a anáise do software, mas também fornece suporte a um conjunto de métodos bem estabelecidos para verificações de propriedades. É nesse contexto que o software, ALUPAS, responsável por estimar o consumo de energia e o tempo de execução dos sistemas embarcados é apresentado. Por fim, um caso de estudo real, assim como tamb´em, exemplos customizados são apresentados com a finalidade de mostrar a aplicabilidade desse trabalho, onde usuários não especializados não precisam interagir diretamente com o formalismo de redes de Petri.
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Klöckl, Bernd. "Impacts of energy storage on power systems with stochastic generation." Konstanz Hartung-Gorre, 2007. http://d-nb.info/987143360/04.
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Chen, Tianyu. "Simulation of the thermal and electrical performance of a novel PVT-PCM system." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49210/.
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This study provides an insight into the fundamentals of PV performance enhancement under different environmental conditions. The study also presents a new concept of PCM integrated PVT system which has a better performance from both electrical and thermal perspectives. The study employs both analytical and computational techniques to investigate the PV performance under the effect of different parameters such as wind speed, solar radiation level, ambient temperature and additional cooling condition. A parametric analysis of the PCM is also carried out under different solar radiation level, water inlet temperature and flow speed. Additional analysis regarding to the effects of PCM’s thermal physical properties against its thermal performance is also presented. A validation analysis is carried out prior to the parametric analysis to ascertain the reliability of the CFD models used, the prediction result of the CFD model is compared with analytical calculations as well as data from literature. The study found that the active water cooling is the best solution which can provide guaranteed performance enhancement regardless effects of ambient conditions. The novel PVT-PCM system is found to have a noticeable electrical performance enhancement over conventional PV panel as well as having the ability to store a significant amount of thermal energy. It is found that the PVT-PCM system has much lower PV cell temperature (maximum temperature reduction of 36.5°C and 38.3°C respectively) compared to conventional PV systems when used in both Nottingham and Shanghai area, hence provide up to 5.4kWh (5.7kWh in Shanghai) more energy per unit module. The stored thermal energy could be utilized to provide moderate heating to air and/or water. The air preheated by PVT-PCM system could satisfy space heating requirement during April to October in Nottingham without any additional energy consumption. On the other hand, the preheated water could reduce boiler heating energy from up to 20% and 41% respectively for Nottingham and Shanghai climate. The overall performance benefits of the proposed PVT-PCM system could be greater if used in hotter climates. Finally, a cost analysis was carried to prove the whole system is financially feasible for use in both climates of Nottingham and Shanghai with a discounted payback period of 10.67 and 12.83 years respectively.
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Widha, Kusumaningdyah. "A Simulation-Based Design and Evaluation Framework for Energy Product-Service System in Liberalized Electricity Markets." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263755.
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京都大学新制・課程博士
博士(エネルギー科学)
甲第23294号
エネ博第419号
京都大学大学院エネルギー科学研究科エネルギー社会・環境科学専攻
(主査)教授 手塚 哲央, 教授 宇根﨑 博信, 准教授 MCLELLAN Benjamin
学位規則第4条第1項該当
Doctor of Energy Science
Kyoto University
DFAM
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Frisk, Malin. "Simulation and Optimization of a Hybrid Renewable Energy System for application on a Cuban farm." Thesis, Uppsala universitet, Fasta tillståndets fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-317876.
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This paper presents an analysis of the feasibility of utilizing a hybrid renewable energy system to supply the energy demand of a milk and meat farm in Cuba. The study performs simulation and optimization to obtain a system design of a hybrid renewable energy system for application on the farm Desembarco del Granma in the Villa Clara province in the central part of Cuba, for three different cases of biomass availability. The energy resources considered are solar PV, biogas, and wind. A field study is carried out to evaluate the energy load and the biomass resource available for biogas production of the farm Desembarco del Granma, and the feasibility of biogas electrification is evaluated for the three different scenarios of biomass availability. The field study methodology includes semi structured interviews and participant observation for information collection. The farm Desembrero del Granma is estimated to have a scaled annual average electrical load of 264 kWh/day with peak load 26.34 kW, while the scaled annual average deferrable load of the farm was estimated to be 76 kWh/day with a peak load 16 kW. The thermal load was find to consist primarily of energy for water heating and cooking. The thermal demand for cooking was estimate to be 4.5 kWh per day, while the thermal load for water heating was not estimated. The thermal energy need for water heating is assumed to be provided for by solar thermal energy, and is not included in the energy system models of this study. For the modeling, the thermal demand for cooking is assumed to be provided by combustion of biogas. System simulation and optimization in regard to energy efficiency, economic viability and environmental impact is carried out by applying the Hybrid Optimization Model for Electric Renewables (HOMER) simulation and optimization software tool. For two of the biomass scenarios, the optimized energy systems received in HOMER were identical; hence only two biomass scenarios were analyzed. The first one represents the current biomass collected and the biogas production capacity of the farm (including the one not yet utilized), and the second one represents the amount of biomass available if the animals would be gathered in the same place all of the time. A PV-wind hybrid energy system with 100 kW PV installed capacity, 30 kW wind power installed capacity consisting of 10 wind turbines of the size 3 kW, a battery bank of 100 batteries (83.4 Ah/24 V), and a 100 kW inverter is considered the most feasible solution for the current biomass scenario. For the increased biomass scenario, a PV-biogas hybrid energy system configuration of 5 kW PV installed capacity, a 60 kW biogas generator, and an inverter of the size 10 kW is considered the most feasible option. Biogas electrification is shown to not be economically feasible for the current biomass scenario during the conditions modeled in this study, but for the increased biomass scenario biogas electrification was shown to be a feasible option. If the farm would build more biodigestors, biogas electrification could thereby be effective from a financial point of view.
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Baumann, Lars. "Improved system models for building-integrated hybrid renewable energy systems with advanced storage : a combined experimental and simulation approach." Thesis, De Montfort University, 2015. http://hdl.handle.net/2086/11103.
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The domestic sector will play an important role in the decarbonisation and decentralisation of the energy sector in the future. Installation numbers of building-integrated small-scale energy systems such as photovoltaics (PV), wind turbines and micro-combined heat and power (CHP) have significantly increased. However, the power output of PV and wind turbines is inherently linked to weather conditions; thus, the injected power into the public grid can be highly intermittent. With the increasing share of renewable energy at all voltage levels challenges arise in terms of power stability and quality. To overcome the volatility of such energy sources, storage technologies can be applied to temporarily decouple power generation from power consumption. Two emerging storage technologies which can be applied at residential level are hydrogen systems and vanadium-redox-flow-batteries (VRFB). In addition, the building-integrated energy sources and storage system can be combined to form a hybrid renewable energy system (HRES) to manage the energy flow more efficiently. The main focus of this thesis is to investigate the dynamic performance of two emerging energy storage technologies, a hydrogen loop composed of alkaline electrolyser, gas storage and proton exchange membrane (PEM) fuel cell, and a VRFB. In addition, the application of building-integrated HRES at customer level to increase the self-consumption of the onsite generated electricity and to lower the grid interaction of the building has been analysed. The first part deals with the development of a research test-bed known as the Hybrid Renewable Energy Park (HREP). The HREP is a residential-scale distributed energy system that comprises photovoltaic, wind turbine, CHP, lead acid batteries, PEM fuel cell, alkaline electrolyser and VRFB. In addition, it is equipped with programmable electronic loads to emulate different energy consumption patterns and a charging point for electric vehicles. Because of its modular structure different combinations of energy systems can be investigated and it can be easily extended. A unified communication channel based on the local operating network (LON) has been established to coordinate and control the HREP. Information from the energy systems is gathered with a temporal resolution of one second. Integration issues encountered during the integration process have been addressed. The second part presents an experimental methodology to assess the steady state and dynamic performance of the electrolyser, the fuel cell and the VRFB. Operational constrains such as minimum input/output power or start-up times were extracted from the experiments. The response of the energy systems to single and multiple dynamic events was analysed, too. The results show that there are temporal limits for each energy system, which affect its response to a sudden load change or the ability to follow a load profile. Obstacles arise in terms of temporal delays mainly caused by the distributed communication system and should be considered when operating or simulating a HRES at system level. The third part shows how improved system models of each component can be developed using the findings from the experiments. System models presented in the literature have the shortcoming that operational aspects are not adequately addressed. For example, it is commonly assumed that energy systems at system level can respond to load variations almost instantaneously. Thus, component models were developed in an integrated manner to combine theoretical and operational aspects. A generic model layout was defined containing several subsystems, which enables an easy implementation into an overall simulation model in MATLAB®/Simulink®. Experimental methods were explained to extract the new parameters of the semi-empirical models and discrete operational aspects were modelled using Stateflow®, a graphical tool to formulate statechart diagrams. All system models were validated using measured data from the experimental analysis. The results show a low mean-absolute-percentage-error (<3%). Furthermore, an advanced energy management strategy has been developed to coordinate and to control the energy systems by combining three mechanisms; statechart diagrams, double exponential smoothing and frequency decoupling. The last part deals with the evaluation, operation and control of HRES in the light of the improved system models and the energy management strategy. Various simulated case studies were defined to assess a building-integrated HRES on an annual basis. Results show that the overall performance of the hydrogen loop can be improved by limiting the operational window and by reducing the dynamic operation. The capability to capture the waste heat from the electrolyser to supply hot water to the residence as a means of increasing the overall system efficiency was also determined. Finally, the energy management strategy was demonstrated by real-time experiments with the HREP and the dynamic performance of the combined operation has been evaluated. The presented results of the detailed experimental study to characterise the hydrogen loop and the VRFB as well as the developed system models revealed valuable information about their dynamic operation at system level. These findings have relevance to the future application and for simulation studies of building-integrated HRES. There are still integration aspects which need to be addressed in the future to overcome the proprietary problem of the control systems. The innovations in the HREP provide an advanced platform for future investigations such as electric-vehicles as decentralised mobile storage and the development of more advanced control approaches.
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Chandler, Shawn Aaron. "Global Time-Independent Agent-Based Simulation for Transactive Energy System Dispatch and Schedule Forecasting." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2212.
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Electricity service providers (ESP) worldwide have increased their interest in the use of electrical distribution, transmission, generation, storage, and responsive load resources as integrated systems. Referred to commonly as "smart grid," their interest is driven by widespread goals to improve the operations, management and control of large-scale power systems. In this thesis I provide research into a novel agent-based simulation (ABS) approach for exploring smart grid system (SGS) dispatch, schedule forecasting and resource coordination. I model an electrical grid and its assets as an adaptive ABS, assigning an agent construct to every SGS resource including demand response, energy storage, and distributed generation assets. Importantly, real time is represented as an environment variable within the simulation, such that each resource is characterized temporally by multiple agents that reside in different times. The simulation contains at least as many agents per resource as there are time intervals being investigated. These agents may communicate with each other during the simulation, but only agents assigned to represent the same unique resource may exchange information between time periods. Thus, confined within each time interval, each resource agent may also interact with other resource agents. As with any agent-based model, the agents may also interact with the environment, in this case, containing forecasted environment, load and price information specific to each time interval. The resulting model is a time-independent global approach capable of: (1) capturing time-variant local grid conditions and distribution grid load balancing constraints; (2) capturing time-variant resource availability and price constraints, and finally, (3) simulating efficient unit-commitment real-time dispatches and schedule forecasts considering time-variant forecasted transactive market prices. This thesis details the need for such a system, discusses the form of the ABS, and analyzes the predictive behavior of the model through a critical lens by applying the resulting proof-of-concept simulation to a set of comprehensive validation scenarios. The resulting analysis demonstrates ABS as an effective tool for real-time dispatch and SGS schedule forecasting as applied to research, short-term economic operations planning and transactive systems alike. The model is shown to converge on economic opportunities regardless of the price or load-forecast shape and to correctly perform least-cost dispatch and schedule forecasting functionality.
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Shayesteh, Ebrahim. "Efficient Simulation Methods of Large Power Systems with High Penetration of Renewable Energy Resources : Theory and Applications." Doctoral thesis, KTH, Elektriska energisystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-158946.
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Electrical energy is one of the most common forms of energy these days. Consequently, electric power system is an indispensable part of any society. However, due to the deregulation of electricity markets and the growth in the share of power generation by uncontrollable renewable energies such as wind and solar, power system simulations are more challenging than earlier. Thus, new techniques for simplifying these simulations are needed. One important example of such simplification techniques is the power system reduction. Power system reduction can be used at least for four different purposes: a) Simplifying the power system simulations, b) Reducing the computational complexity, c) Compensating the data unavailability, and d) Reducing the existing uncertainty. Due to such reasons, power system reduction is an important and necessary subject, but a challenging task to do. Power system reduction is even more essential when system operators are facing very large-scale power systems and when the renewable energy resources like hydro, wind, and solar have a high share in power generation. This thesis focuses on the topic of large-scale power system reduction with high penetration of renewable energy resources and tries to pursue the following goals: • The thesis first reviews the different methods which can be used for simplifying the power system studies, including the power system reduction. A comparison among three important simplification techniques is also performed to reveal which simplification results in less error and more simulation time decrement. • Secondly, different steps and methods for power system reduction, including network aggregation and generation aggregation, are introduced, described and discussed. • Some improvements regarding the subject of power system reduction, i.e. on both network aggregation and generation aggregation, are developed. • Finally, power system reduction is applied to some power system problems and the results of these applications are evaluated. A general conclusion is that using power system simplification techniques and specially the system reduction can provides many important advantages in studying large-scale power systems with high share of renewable energy generations. In most of applications, not only the power system reduction highly reduces the complexity of the power system study under consideration, but it also results in small errors. Therefore, it can be used as an efficient method for dealing with current bulk power systems with huge amounts of renewable and distributed generations.The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively. QC 20150116
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Zhu, Nanhao. "Simulation and optimization of energy consumption in wireless sensor networks." Phd thesis, Ecole Centrale de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-01002108.
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Les grandes évolutions de la technique de systèmes embarqués au cours des dernières années ont permis avec succès la combinaison de la détection, le traitement des données, et diverses technologies de communication sans fil tout en un nœud. Les réseaux de capteurs sans fil (WSN) qui se composent d'un grand nombre de ces nœuds ont attiré l'attention du monde entier sur les établissements scolaires et les communautés industrielles, puisque leurs applications sont très répandues dans des domaines tels que la surveillance de l'environnement, le domaine militaire, le suivi des événements et la détection des catastrophes. En raison de la dépendance sur la batterie, la consommation d'énergie des réseaux de capteurs a toujours été la préoccupation la plus importante. Dans cet article, une méthode mixte est utilisée pour l'évaluation précise de l'énergie sur les réseaux de capteurs, ce qui inclut la conception d'un environnement de SystemC simulation base au niveau du système et au niveau des transactions pour l'exploration de l'énergie, et la construction d'une plate-forme de mesure d'énergie pour les mesures de nœud banc d'essai dans le monde réel pour calibrer et valider à la fois le modèle de simulation énergétique de nœud et le modèle de fonctionnement. La consommation d'énergie élaborée de plusieurs différents réseaux basés sur la plate-forme de nœud sont étudiées et comparées dans différents types de scénarios, et puis des stratégies globales d'économie d'énergie sont également données après chaque scénario pour les développeurs et les chercheurs qui se concentrent sur la conception des réseaux de capteurs efficacité énergétique. Un cadre de l'optimisation basée sur un algorithme génétique est conçu et mis en œuvre à l'aide de MATLAB pour les réseaux de capteurs conscients de l'énergie. En raison de la propriété de recherche global des algorithmes génétiques, le cadre de l'optimisation peut automatiquement et intelligemment régler des centaines de solutions possibles pour trouver le compromis le plus approprié entre la consommation d'énergie et d'autres indicateurs de performance. Haute efficacité et la fiabilité du cadre de la recherche des solutions de compromis entre l'énergie de nœud, la perte de paquets réseau et la latence ont été prouvés par réglage paramètres de l'algorithme CSMA / CA de unslotted (le mode non-beacon de IEEE 802.15.4) dans notre simulation basé sur SystemC via une fonction de coût de la somme pondérée. En outre, le cadre est également disponible pour la tâche d'optimisation basée sur multi-scénarios et multi-objectif par l'étude d'une application médicale typique sur le corps humain.
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Wong, Kin-chuen, and 黃健全. "Optimization of building cooling system based on genetic algorithms and thermal energy storage." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B45701416.
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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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Elgendy, Youssef Ahmed Mohammad. "Improved multiple loop simulation method applied to a proposed dish ericsson solar thermal power system." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/17785.
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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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Roper, Daniel. "Energy based control system designs for underactuated robot fish propulsion." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1560.
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In nature, through millions of years of evolution, fish and cetaceans have developed fast efficient and highly manoeuvrable methods of marine propulsion. A recent explosion in demand for sub sea robotics, for conducting tasks such as sub sea exploration and survey has left developers desiring to capture some of the novel mechanisms evolved by fish and cetaceans to increase the efficiency of speed and manoeuvrability of sub sea robots. Research has revealed that interactions with vortices and other unsteady fluid effects play a significant role in the efficiency of fish and cetaceans. However attempts to duplicate this with robotic fish have been limited by the difficulty of predicting or sensing such uncertain fluid effects. This study aims to develop a gait generation method for a robotic fish with a degree of passivity which could allow the body to dynamically interact with and potentially synchronise with vortices within the flow without the need to actually sense them. In this study this is achieved through the development of a novel energy based gait generation tactic, where the gait of the robotic fish is determined through regulation of the state energy rather than absolute state position. Rather than treating fluid interactions as undesirable disturbances and `fighting' them to maintain a rigid geometric defined gait, energy based control allows the disturbances to the system generated by vortices in the surrounding flow to contribute to the energy of the system and hence the dynamic motion. Three different energy controllers are presented within this thesis, a deadbeat energy controller equivalent to an analytically optimised model predictive controller, a $H_\infty$ disturbance rejecting controller with a novel gradient decent optimisation and finally a error feedback controller with a novel alternative error metric. The controllers were tested on a robotic fish simulation platform developed within this project. The simulation platform consisted of the solution of a series of ordinary differential equations for solid body dynamics coupled with a finite element incompressible fluid dynamic simulation of the surrounding flow. results demonstrated the effectiveness of the energy based control approach and illustrate the importance of choice of controller in performance.
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Asim, Muhammad. "Simulation of solar powered absorption cooling system for buildings in Pakistan." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/simulation-of-solar-powered-absorption-cooling-system-for-buildings-in-pakistan(9f1a4400-fd4c-4ece-876f-98bb1aed5404).html.
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This research investigates the potential of a solar powered cooling system for single family houses in Pakistan. The system comprises water heating evacuated tube solar collectors, a hot water storage tank, and an absorption chiller. A literature review was carried out covering: • Energy situation, climate, and renewable energy potential in Pakistan; • Energy and thermal comfort in buildings, particularly for hot climates; • Solar collectors and solar cooling systems, particularly for hot climates; • Dynamic thermal simulation and weather data for solar energy systems and buildings. It was found that Pakistan is short of energy and that there is a great need to cool buildings. Renewable energy cooling systems are, therefore, of interest. The system described above was selected, as it was found that solar energy is abundant in Pakistan when cooling is required; thermal systems can be more economical than photovoltaics for hot climates and suitable components (collectors, absorption chillers, etc.) are commercially available. The TRNSYS dynamic thermal simulation program was selected as the main research tool, as it has been tested for solar energy and building applications by many researchers and suitable experimental facilities were not available. A simple typical building in Pakistan with a solar cooling system was simulated. Optimum values for key parameters were found by repeated simulations. It was concluded that the system would be able to provide cooling when required without an auxiliary heat source, and that an evacuated tube collector with a gross area of 12 m2, a collector flow rate of 165 kg/h, and a storage tank volume of 2 m3 would provide satisfactory performance for a 3.52 kW absorption chiller integrated with 42m3 single room. The results were in good agreement with published results from other researchers. Sensitivity analysis was carried out for the collector area, collector flow rate and storage tank size. It was found that varying the collector area had the largest effect on system performance, followed by varying the storage tank volume. Varying the collector flow rate had the smallest effect. It is recommended that solar cooling systems should be considered for Pakistan, and that further research should be carried out into reducing building cooling loads, using surplus heat for other loads, improving the performance of the proposed solar cooling system, and comparing it with other systems such as photovoltaics.