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Rohdin, Patrik. "Energy efficiency and ventilation in Swedish industries barriers, simulation and control strategy." Doctoral thesis, Linköpings universitet, Energisystem, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-15531.
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The energy issue is presently in focus worldwide. This is not only due to increasing environmental concern regarding energy related emissions, but also due to the trend of increasing energy prices. Energy usage in the industrial sector in Sweden today represents about one third of the national energy use. A substantial part of that is related to support processes such as heating, ventilation and cooling systems. These systems are important as they are related both to energy cost and indoor climate management as well as to the health of the occupants. The purpose of this thesis is to reach a more comprehensive view on industrial energy efficiency and indoor environment issues related to industrial ventilation. This has been studied in three themes where the first part addresses barriers to energy efficiency in Swedish industries, the second theme discuss simulation as decision support, and the third studies the variable air volume system in industrial facilities. In the first theme three different studies were made: the first studies non-energy intensive companies in Oskarshamn in Sweden, the second studies the energy intensive foundry industry and the third study was part of an evaluation of a large energy efficiency program called Project Highland. These studies had several findings in common, such as the importance of a strategic view on the energy issue and the presence of a person with real ambition with power over investment decisions related to energy issues at the company. The studies also show that several information related barriers are important for decision makers at the studied companies. This shows that information related barriers are one reason in why energy efficient equipment is not implemented. In the second theme the use of simulation in the form of Computational Fluid Dynamics (CFD) and Building Energy Simulation (BES) are used as decision support for industrial ventilation related studies at two different industries, one foundry is investigated and one dairy. BES has mainly been used to simulate energy and power related parameters while CFD was used to give a detailed description of the indoor and product environment. Together these methods can be used to better evaluate the energy, indoor and product environment and thus enable the implementation of more efficient heating, ventilation and air-conditioning systems. In the third theme the use of Variable Air Volume (VAV) systems was evaluated, and was found to be an efficient way to reduce energy use at the studied sites. At the studied foundry the VAV system is predicted to reduce space heating and electricity use by fans by about 30%, and in the dairy case by about 60% for space heating and 20% for electricity.
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Dowrani, Ali Akbar Gharooni. "Efficiency of air cooler coil defrost methods and the effect of these methods on the refrigeration cycle performance." Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316876.
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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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Rundblad, Mattias, and Nasim Walid. "Systemlösningar för ventilation på en förskola : Energi- samt ekonomiutvärdering för CAV- och VAV-ventilation för olika luftbehandlingsaggregat." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-36341.
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Energieffektiviseringar behövs för att klara klimatmålen. Syftet med detta arbete har därför varit att undersöka ventilationen i förskolebyggnaden Rymden i Eskilstuna kommun. Fokus i arbetet har legat på att göra en analys på energibesparingar där variabelt luftflöde, VAV-system och konstant luftflöde, CAV-system jämförs i tre olika scenarier. Metodiken för att lösa arbetets frågeställningar har varit genom informationsinsamling, beräkningsprogram, intervju samt platsbesök. Informationsinsamling har varit i form av vetenskapliga tidskrifter samt arbeten som behandlar det aktuella problemområdet. Olika programvaror har använts, dessa är MagiCAD, IDA ICE, Sektionsdata 4.21 samt Microsoft Excel. För ökad förståelse för den aktuella byggnaden har platsbesök gjorts på förskolebyggnaden samt en intervju med den projektöransvarige för ventilationen i förskolan. Resultatet visar att den mest energieffektiva systemlösningen är en roterande värmeväxlare med VAV-styrning i kombination med en korsströmsvärmeväxlare för köksavdelningen. VAV-styrning med en sådan systemlösning har en total årlig energianvändning på 20 684 kWh, medan CAV-systemet med samma systemlösning använder 30 900 kWh. Ekonomisk analys visar däremot att CAV-systemet med samma systemlösning är mest lönsam. Den totala livscykelkostnaden, LCC ligger på 2 386 857 kr för CAV-systemet vid en kalkyltid på 30 år, i jämförelse med 2 420 117 kr för VAV-systemet. För att VAV-systemet skall vara lönsam, visar känslighetsanalysen att kalkylräntan måste sjunka från 5 % till 2,56 % eller energiprisutvecklingen öka med 2,44 % årligen eller en sänkning av den årliga underhållskostnaden för VAV-styrning med 2 164 kr. Övrig känslighetsanalys visar att vid nederbörd då personer stannar inomhus är det fördel för VAV-systemet, då skillnaden i total LCC-kostnad sjunker med 1 758 kr. Vid 74 % av personnärvaro minskar LCC-skillnaden mellan systemen från 39 240 kr till 26 371 kr, alltså utgör detta även en fördel för VAV-systemet. Slutsatsen som dras för förskolebyggnaden Framtiden är att större energibesparingar kan göras med ett VAV-system, men ett CAV-system är bättre ur en ekonomisk synpunkt. Känslighetsanalysen visar dock att små förändringar behövs för att VAV-systemet skall bli ekonomiskt lönsamt. Andra faktorer som påverkar valet mellan VAV- och CAV-system är exempelvis en minskning av personnärvaron relativt till det dimensionerade. En sådan minskning utgör en fördel för VAV-systemet. Detta på grund av att med ett CAV-system överventileras byggnaden. Även högre specifik fläkteffekt har en stor betydelse i valet, då mer energiåtgång till fläktarna leder till större energibesparing för VAV-system. En högre temperaturverkningsgrad för luftbehandlingsaggregat medför däremot en fördel för CAV-system.This thesis work has been done in collaboration with Sweco Systems in Eskilstuna, Sweden. The purpose with this work is to investigate the ventilation in a preschool in Eskilstuna. The focus of the work is to analyze the potential energy savings of using a variable air volume system instead of a constant air volume system. An analysis is also made to investigate the economical profitability of three different scenarios. The method used to solve the problem formulation has been through gathering information, in form of scientific journals in the current problem area. Information has also been gathered through an interview and a site visit. Various software has been used in this thesis work for calculations, such as MagiCAD, IDA ICE, Sektionsdata 4.21 and Microsoft Excel. The result shows that the most energy efficient solution is a rotary heat exchanger with variable air volume control in combination with a cross-flow heat exchanger for the kitchen section. However, the most profitable solution from an economical point of view is the same system, but with constant air volume control. Sensitivity analysis shows that for a profitable variable air volume system, either the interest rate has to be lowered from 5 % to 2,56 %, the energy price needs to increase by 2,44 % yearly. Or maintenance cost for the variable air volume system needs to be lowered by 2 164 kr. The conclusion of this thesis work is that energy savings can be done with a variable air volume system. However from an economical point of view, the constant air volume is better than variable air volume for the investigated preschool. The sensitivity analysis shows that small changes are needed to make a variable air volume system profitable. The choice between the systems are influenced by certain factors. A decrease of the attendance than the dimensioned are an advantage for variable air volume systems. This is due to the fact that a constant air volume system ventilates more than needed. A higher specific fan power number are also of great importance in the choice, as more energy consumption by the fans leads to greater energy savings for variable air volume systems.
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Widström, Torun. "Enhanced Energy Efficiency and Preservation of Historic Buildings : Methods and Tools for Modeling." Licentiate thesis, KTH, Byggnadsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102544.
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As the environmental impacts of the energy usage of the world today becomes more and more evident, enhancement of energy performance of the already existing building stock becomes more urgent. Buildings belonging to the cultural heritage are often the ones that are most difficult to deal with in this context. The subject of this thesis is the use of building simulation of historic buildings. The task here is to identify and when necessary develop simulation tools and methods that are suitable for planning of retrofitting strategies in historic buildings, and to identify and analyze what demands such tools and methods would have to fulfill, in what contexts different simulation strategies are suitable, how the demands on the tools might be met and what results and how the results would facilitate the decision making process in the most optimal way. A powerful means to acquire such analyses is the use of whole-building simulation. In the case of historical buildings there are several aspects to take into consideration, determining the choice of simulation tool and method. This thesis includes Investigation of the variability of the demands on simulation tools and methods that the historic buildings pose, and its implication on complexity of the simulation process, and suggestion of a complexity index tool. Investigation of the whole-building simulation process and how it complies with the demands identified, and how the exergy concept can be used, exemplified by a case study. Identification of a need for a tool and method for a large amount of cases not easily covered by abundantly available tools and methods Suggestion of a tool and method to address these cases, and presentation of a case study where the suggested tool and method have been applied, with good agreement between the simulated and measured values. One important feature of the suggested tool is the Very Small Wall-part Method, that includes the assessment of especially damage prone points into the whole-building simulation model, otherwise unable to accommodate these points. Another is the damage risk assessment feature where a mould risk prediction tool is presented.QC20120920
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Vadambacheri, Manian Karthik. "Novel Methods to Improve the Energy Efficiency of Multi-core Synchronization Primitives." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511858440610247.
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Brugnera, Rosilene Regolão. "Potencial de economia de energia em edifícios de escritórios com estratégias de ventilação híbrida." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/102/102131/tde-30102014-152311/.
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Grandes fachadas envidraçadas têm se tornado comuns em edifícios de escritórios, desconsiderando elementos importantes como as janelas na redução do seu consumo energético, por meio da obtenção da iluminação e ventilação naturais. Dessa forma, o objetivo principal desta pesquisa é avaliar o potencial de economia de energia em edifícios de escritórios por meio da utilização de estratégias de ventilação híbrida, em duas regiões climáticas brasileiras distintas. O método consiste em medições com sensores para aferir dados de temperatura e umidade no momento em que são acionados os condicionadores de ar, a fim de obter a temperatura de setpoint. Tal resultado foi utilizado em simulações computacionais do desempenho térmico e da iluminação natural através dos programas EnergyPlus e Daysim respectivamente. Foi analisado um modelo de edifício de escritórios, com um sistema de iluminação eficiente (dimerizável) em que foram inseridas estratégias de ventilação híbrida, a fim de se obter a influência na economia de energia devido à redução do uso do condicionamento artificial de ar (nos períodos em que isso foi possível). Os resultados apresentaram uma redução no consumo do ar condicionado em torno dos 30%, enquanto que o impacto da ventilação híbrida no consumo de energia total do edifício apresentou-se na faixa dos 12%. Todavia, com a utilização de tais estratégias alcançou-se uma redução de até 84% do desconforto térmico nos ambientes. Como conclusão do trabalho tem-se que, utilizando-se um sistema de iluminação natural eficiente, o impacto da ventilação híbrida no potencial de economia de energia, dependendo do caso, pode não ser tão expressivo, ao passo que a redução no nível de desconforto térmico é bastante significativa.Large glazed facades have become common in office buildings and important elements, like windows to obtain natural lighting and ventilation to reduce their energy consumption have been ignored. This dissertation evaluates the potential of energy savings in office buildings through the use of hybrid ventilation strategies in two different Brazilian climatic regions. The method consists in measuring sensors for collecting humidity and temperature data at the time air conditioners are started so as to obtain the setpoint temperature. The results were used in computer simulations of both thermal performance and daylighting through EnergyPlus and Daysim software, respectively. A model of the office building, with efficient lighting (dimmable), was analyzed. Hybrid ventilation strategies were adopted for verifying the influence on energy savings due to a reduced use of artificial air conditioning (in periods in which it was possible). The results show a 30% reduction in the consumption of air conditioning and a 12% impact of hybrid ventilation on the total energy consumption of the building. However, such strategies caused an 84% reduction in the thermal discomfort in the environment. According to the results, the impact of hybrid ventilation on the potential energy savings by the use of efficient daylighting, in some cases, may not be so significant, whereas the reduction in the level of thermal discomfort is quite significant.
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Ertem-Müller, Senem [Verfasser]. "Numerical Efficiency of Implicit and Explicit Methods with Multigrid for Large Eddy Simulation in Complex Geometries / Senem Ertem-Müller." Aachen : Shaker, 2003. http://d-nb.info/1181602696/34.
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Mason, Kevin Richard. "Development of numerical schemes to improve the efficiency of CFD simulation of high speed viscous aerodynamic flows." Thesis, Swansea University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678434.
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Starke, Martin, Benjamin Beck, Denis Ritz, Frank Will, and Jürgen Weber. "Frequency based efficiency evaluation - from pattern recognition via backwards simulation to purposeful drive design." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71072.
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The efficiency of hydraulic drive systems in mobile machines is influenced by several factors, like the operators’ guidance, weather conditions, material respectively loading properties and primarily the working cycle. This leads to varying operation points, which have to be performed by the drive system. Regarding efficiency analysis, the usage of standardized working cycles gained through measurements or synthetically generated is state of the art. Thereby, only a small extract of the real usage profile is taken into account. This contribution deals with process pattern recognition (PPR) and frequency based efficiency evaluation to gain more precise information and conclusion for the drive design of mobile machines. By the example of an 18 t mobile excavator, the recognition system using Hidden – Markov - Models (HMM) and the efficiency evaluation process by means of backwards simulation of measured operation points will be described.
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Shi, Hongsen. "Building Energy Efficiency Improvement and Thermal Comfort Diagnosis." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555110595177379.
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Scullin, Michelle E. "Integrating Value Stream Mapping and Simulation." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd898.pdf.
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Carpenter, Nolan A. W. "A study of exergy destruction and methods improving second law efficiency in common production engines using a thorough analysis of engine simulation results." Birmingham, Ala. : University of Alabama at Birmingham, 2009. https://www.mhsl.uab.edu/dt/2009m/carpenter.pdf.
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Hauerhof, E. "The assessment of oil products tanker design methods and technologies to enhance the Energy Efficiency Design Index measure by means of computer simulation and trend analysis." Thesis, City, University of London, 2017. http://openaccess.city.ac.uk/17635/.
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The primary objective of this PhD research is to develop an advanced understanding of the necessary and realistic performance expectations from a full form medium size ship system by means of numerical computer modelling. This includes the minimisation of the harmful environmental signature by increasing its efficiency in compliance with the EEDI requirements while in search of how the EEDI methodology might be enhanced. The investigation has focused on a medium sized products tanker acting as a midpoint of the spectrum of ship sizes within the range of 20,000 – 60,000 DWT of this type. In order to solve such an extensive problem, in the first place, it was important to analyse the energy efficient technology market in a structured manner and then, to identify the most favourable fuel consumption reduction methods that can be associated with the examined ship type. Next, an integrated computer simulation model, involving linked engine, propeller and hull analysis programs, has been developed and calibrated with the model tests and sea trial data. The ship system has been analysed under diverse conditions including various propulsion systems, innovative machinery arrangements, efficiency enhancing hydrodynamic appendages as well as changing weather and load conditions. The evaluation of potential benefits associated with the deployment of innovative technology(s), operation profile(s) or their combination has been made by comparing the designated Energy Efficiency Indicators (EDI), namely, the propulsive efficiency, fuel oil consumption, exhaust emissions footprint and EEDI, respectively associated with the technical, fuel savings, environmental and legal perspectives. In addition, such a comprehensive analysis has also helped to detect a number of uncertainties in the current EEDI formulation while pointing out ways in which it can be improved.
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Sakellari, Dimitra. "Modelling the dynamics of domestic low-temperature heat pump heating systems for improved performance and thermal comfort : a systems approach." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-269.
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Baradar, Mohamadreza. "On the Efficiency and Accuracy of Simulation Methods for Optimal Power System Operation : Convex Optimization Models for Power System Analysis, Optimal Utilization of VSC-type DC Wind Farm Grids and FACTS Devices." Doctoral thesis, KTH, Elektriska energisystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166383.
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Recently, significant changes in electric power systems such as rapid developmentof smart grid and electricity market and integration of non-dispatchablesources have added more complexity to the Power Flow Scheduling (PFS) andPower Balancing (PB) models. For instance, non-dispatchable sources introducean increasing level of uncertainty in the electricity market and power system operation.One of the solutions for handling these uncertainties in the power systemoperation is the improvement of system flexibility through a more efficient operationof power systems. On the other hand, efficient operation can be achieved bywell capturing variable behavior of uncertain sources such as wind power sourceswhich in turn demands efficient and robust PFS/PB models. This way, a moreflexible system, capable of efficiently accommodating higher levels of wind powerchanges, can be achieved. All these factors increase a need for PFS/PB models suchas Power Flow (PF) and Optimal Power Flow (OPF) models which can addressthese new challenges in an efficient, reliable, and economic way while supportingthe power system operation and control. In this regard, various solution methodshave been developed for solving different forms of PF/OPF formulation. The difficultyof solving OPF problems increases significantly with increasing network sizeand complexity. One of these complexities is how to model advanced controllable devices such as HVDC grids and Flexible AC Transmission Systems (FACTS) devices.Accurate handling of these complexities has limited the use of OPF in manyreal-world applications mainly because of its associated computational challenges.The main reasons behind computational challenges are nonlinearity and especiallynon-convexity of constraints representing power system and its components. Inthis regard, OPF problems are classified into two main groups. In the first group,researchers adopt Nonlinear programming (NLP) approach to fully represent thenonlinearity of the power system for the sake of accuracy but with the cost of complexityin the model. Computational and theoretical challenges associated withNLP approaches are then used as a motivation towards developing a more simplifiedOPF model, leading to the second group of OPF models known as LinearProgramming (LP) based OPF models. LP approaches are fast, reliable, and especiallyconvex, and therefore guarantee a global optimum to the simplified OPFproblem. The problem of LP approach to OPF is that the LP solution of OPF may not even be a feasible solution of original nonlinear OPF at all. Another issueassociated with LP models is that complex power system devices such as HVDClinks are difficult to be incorporated. These limitations have restricted the applicationof LP approaches for many OPF problems. According to the mentionedadvantages and disadvantages of NLP and LP based OPF models, what we seeks isan OPF model which can have main advantages of both LP OPF models (Efficientnumerical solvers) and full AC OPF models (Results accuracy). In this thesis, wedevelop convex optimization problems which can be adopted as both PF and OPFmodels which are capable of catching the nonlinear nature of power systems asmuch as possible while can be solved by efficient solution methods such as InteriorPoint Methods (IPMs). These OPF models can incorporate HVDC links, windfarm Multi Terminal HVDC (MTDC) grids, and shunt FACTS devices.QC 20150521
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Podola, David. "Parametrická studie zařízení pro zpětné získávání tepla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230445.
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This diploma thesis deals with the impact of changes in operating and geometrical parameters of regenerative heat exchanger on the efficiency of decentralized ventilation units with heat recovery. Decentralized ventilation unit can be used for ventilation of family houses or smaller administration buildings. Output of this work is to determine the efficiency of a particular produced model of decentralized ventilation unit and overview of the possibilities increased efficiency of heat recovery of this units.
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Santesso, Caroline Antonelli. "Integração da ventilação híbrida e da iluminação natural em saletas comerciais na cidade de São Paulo: influência de parâmetros de projeto." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/102/102131/tde-23012017-112928/.
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Atualmente, os edifícios selados hermeticamente e com as chamadas \"peles de vidro\" estão presentes em diversos países, e possuem, como consequência, um elevado consumo de energia elétrica para conseguir manter o conforto ambiental dos usuários. Contudo, é possível se beneficiar de uma maior eficiência energética nesses espaços através da combinação de soluções ativas e passivas. Esse estudo tem como objetivo principal avaliar a influência de parâmetros de projetos, tais como o formato da sala, tamanho e orientação das aberturas na fachada, no consumo de energia e no conforto visual em saletas comerciais com ventilação híbrida e integração da iluminação natural com a artificial na cidade de São Paulo. As saletas comerciais analisadas possuem uma área média, diferentes formatos e diferentes aberturas em uma só fachada, representando a solução arquitetônica mais comum encontrada nesse tipo de edifício. Através de análise energética realizada por meio do programa EnergyPlus e da análise lumínica com o programa DIVA-for-Rhino, verificou-se que o formato da sala é essencial para a decisão de um percentual de área de abertura na fachada (PAF) que consuma menos energia. Os resultados mostraram que o uso da ventilação híbrida sempre representou uma economia, atingindo uma redução de até 51% do consumo do ar condicionado para resfriamento e até 26% do consumo de energia total, com os PAF´s de 40, 70 e 100%. Seria interessante considerar elementos de proteção solar que não diminuam a eficácia da ventilação e iluminação naturais nesses ambientes, para se aliar o baixo consumo de energia com menores riscos de ofuscamento. Desta forma, o trabalho auxilia a incorporação destas estrategias para uma maior economia de energia no desenvolvimento do projeto arquitetônico desta tipologia de edifício comercial.Nowadays, sealed airtight office buildings and so-called \"glass curtain wall\" are present in many countries, and have as a result a high consumption of electric energy to be able to maintain the environmental comfort of the users. However, the combination of passive and active strategies could improve the energy efficiency in these spaces. This study aims to evaluate the design parameters influence, such as rooms shape, the openings size and orientation, in the energy consumption and in the visual comfort in cellular offices with hybrid ventilation system and the integration of daylight and artificial lighting in São Paulo. The analyzed cellular offices have an average area, different shapes and different openings in one facade, representing the more common architectural characteristics found in this type of building in that context. Energy analyses in EnergyPlus and daylight studies using DIVA-for-Rhino were conducted. It was found that the rooms shape is essential for the determination of the window-to-wall-ratio (WWR) for reducing energy consumption. The results showed that the hybrid ventilation use always represented an economy, reaching reduction values up to 51% in the consumption of air conditioning for cooling and up to 26% in cellular offices total consumption, with a WWR of 40, 70 and 100%. It would be interesting to consider sun shading elements that do not reduce the effectiveness of natural ventilation and daylighting in these environments to combine low power consumption with a lower risk of glare. In this way, the work helps the incorporation of these strategies for save energy in the development of the architectural design of this type of commercial building.
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Costa, Herson Vargas da. "Estudo teórico da eficiência de uma usina termelétrica baseado em dados reais." Universidade do Vale do Rio dos Sinos, 2012. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3843.
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CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico
Neste trabalho, foi realizada a simulação do ciclo térmico da Usina Termoelétrica São Jerônimo – UTSJ. A Usina, muito antiga, possui caldeira do tipo grelha. Na mesma Usina foi instalada uma caldeira experimental de leito fluidizado, para funcionar em paralelo com a existente. O trabalho é iniciado com a modelagem de um ciclo de Rankine simples e segue evoluindo até se estabelecer a configuração mais adequada e representativa na tarefa de simular o modo de trabalho da Usina Termelétrica São Jerônimo – UTSJ. Desta forma, foram adotadas as considerações mais convencionais na prática de projeto de centrais termelétricas cujos sistemas térmicos baseiam-se no ciclo de Rankine. As simulações, que se caracterizam pela resolução simultânea das equações que modelam o ciclo e seus componentes, foram efetuadas através de programa IPSE-pro®. As simulações foram aplicadas para a obtenção dos resultados mais importantes na análise de sistemas térmicos, tais como rendimento térmico do ciclo, potência, vazões mássicas do sistema, calor trocado no gerador de vapor e no condensador, entre outros. Por fim, com objetivo de melhorar o rendimento térmico da planta, são apresentadas algumas alternativas ao sistema atual, tais como o aumento de eficiência da caldeira mediante substituição ou a adição de uma caldeira em paralelo à original.
In this work was made the simulation of the thermal cycle of São Jerônimo - UTSJ thermal power plant. The power plant, very old, has a grate boiler. In the same power plant was installed an experimental fluidized bed boiler, workingin parallel with the existing one. The work starts with the modeling of a simple Rankine cycle and evolves up to establish the most suitable and representative configuration to simulate the mode the work of São Jerônimo –UTSJ thermal power plant. Therefore, in this work it was adopted the more conventional considerations in the design practice for thermal power plants whose systems are based on the Rankine cycle. The simulations, which are characterized by the simultaneous solving of equations that model the cycle and its components, were made through the IPSE-pro® software. The simulations were applied to obtain the main results on the analysis of thermal systems such as, thermal efficiency of the cycle, power, system mass flow, heat exchanged in the steam generator and condenser, among others. Finally, in order to improve the thermal efficiency of the plant, some alternatives to the actual system were presented.
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Merabtine, Abdelatif. "Modélisation Bond Graphs en vue de l'Efficacité Énergétique du Bâtiment." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0121/document.
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L'objectif des travaux présentés dans ce mémoire concerne le développement d'un modèle global représentant le couplage de l'enveloppe du bâtiment avec les équipements énergétiques. Une approche systémique appelée les Bond Graphs, peu employée jusqu'ici dans la modélisation des systèmes thermiques, est utilisée. Le modèle global du bâtiment, regroupant sous le même environnement de simulation, les modèles de l'enveloppe du bâtiment, les apports solaires, les émetteurs de chauffage et de rafraîchissement et le système de ventilation, est développé pour reconstituer l'ensemble des articulations énergétiques entre l'enveloppe et les environnements intérieur et extérieur. A travers la modélisation d'un bâtiment multizone, le couplage systémique des modèles de l'enveloppe et des apports solaires est présenté. Par ailleurs, un système combinant un plancher chauffant et un plafond rafraîchissant est étudié à l'aide des modèles des émetteurs de chauffage et de rafraîchissement. Le renouvèlement d'air dans le bâtiment est également concerné par la modélisation Bond Graph. Enfin, des éléments de validation expérimentale sont présentés. Pour cela, la plateforme de tri-génération d'énergie ENERBAT est exploitée. L'objectif est d'étudier le couplage optimal enveloppe du bâtiment - équipements énergétiques pour lequel les modèles BG sont développés. Une étude paramétrique tenant compte des interactions entre les paramètres étudiés est menée sur un projet réel de rénovation. Finalement, une combinaison appropriée des paramètres étudiés a été retenue afin de réduire la consommation énergétique selon la réglementation thermique française (RT2012)Our works focus on the setting of reliable tools able to analyze the interaction between the building envelope and HVAC systems. The developed approach is based on Bond Graphs methodology, a graphical modeling language which is particularly suitable for energy exchanges. A numerical model gathering, under the same simulation environment, sub-models representing the building envelope, the solar gains, the floor heating, the chilled ceiling and the ventilation system, is developed in order to predict the energy interactions between these sub-systems. The multi-zone building model is developed in order to simulate and analyze the overall building thermal behavior. Then, the solar gains model is also included to predict the solar radiation exchanges in a way close to reality. The model of the heating and cooling system, combining the floor heating and the chilled ceiling, is developed in order to improve the thermal comfort of the building. Afterwards, the ventilation system is modeled in order to represent the air exchange inside the building. The experimental validation is carried out on the tri-generation unit integrated with a thermal solar system (platform ENERBAT). Furthermore, the parametrical study was realized in order to gain a better understanding according to the impact of some factors in the energy performance of the single-family building located in Meurthe-et-Moselle region (France). Optimization of several measures, such as insulation of the building envelope, type of glazing, building orientation and ventilation system, is performed to respond to the requirements of the French thermal standard (RT2012)
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Chou, Chin-Sung, and 周金松. "A Study on Natural Ventilation Efficiency of the Separate Opening Model with Screen by CFD Simulation." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/09600338494018788213.
Full textAbstract:
碩士淡江大學
建築學系
88
The design of opening on the envelope of building affects the indoor air quality closely. The inappropriate open will make the people who stay inside for a long time dizzy, headache, sleeping, not attentive, and work ineffectively. The research is to find out the design of open which complies with ventilation trend, i.e. “separate opening model” with above and below ventilative windows. The key points of the research are: 1.The natural ventilation of the thermal buoyancy produced by the heat source from human body in winter. 2.Study the affections of the position and size of opening, and the influence of the position of indoor heat source. 3.In order to consider about the biology environment outdoor, the research also include the affections of airflow through the window screen. The experiment of ventilation in the research adopts the CFD simulation which has been proofed to be reliable in the research of IAQ. The indicators of criticizing the indoor air environment for health are: the concentration of CO2, ACH value and PMV. The controlled causes include the relative position of separate openings, relationship between the size of above and below ventilative windows and the difference of ventilative ability between the people in work area and rest area. The content of the research contains confirming the range of research, analyzing and arranging the document, CFD simulation, analyzing the data and gaining researchful conclusion. The research gets these conclusions by CFD: 1. The ACH of the of separate opening model is more than 36% of it of trandional windows, and 28% of it of rotational windows, which can provide a good project for ventilative opening of bedroom in Taiwan climate. 2. In this research, it has show that the lower opening is more closing to the heat source, the ventilative effect is better. Therefore, in order to get the smallest distance, it is better to make the lower opening be parallel with the heat source (pollution source). 3. In this research, it gets the effect of controlling the ventilation of the thermal buoyancy by changing the distance of heat source. The results have show that as the effect propellent power of thermal buoyancy is worse, the rationality of the opening is more important. 4. Although CFD can not set up propesity of screens, according to some references, the coefficient of airflow through the screen isα; after the experiment, it comes out that α is equal to the amendatory factor of the Value of ACH. The indoor CO2 value can be get by ACH-CO2 regressive formula after getting ACH*.
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Botha, C. P. "Simulation of a building heating, ventilating and air-conditioning system." Diss., 2001. http://hdl.handle.net/2263/26002.
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Simulation is one of the oldest and also among the most important tools available to engineers. In the building Heating, Ventilating and Air-Conditioning (HVAC) community the availability and/or functionality of simulation tools is limited and it is difficult to determine whether the simulation models accurately represent reality. The purpose of this study was to accurately verify one such a simulation model and then to extend the study to two unique applications. Comprehensive structural, comfort and energy audits were performed to construct a suitable simulation model with the aid of the control simulation package: QUICK Control. The model was then verified against measured building data to ensure an accurate representation of the actual dynamic building response. For the first application various control retrofits were evaluated and the highest potential for energy saving was found. Thereafter the model was implemented to investigate the change in indoor air conditions due to failure of HVAC equipment. Heating, ventilating and air-conditioning in buildings consume a significant portion of the available electrical energy in South Africa. Of this energy up to 30% can be saved by improving the HVAC systems currently installed in the buildings. This could result in savings of up to R400 million. For the building used in this study it was found that up to 66% of the HVAC system’s electrical energy consumption could be saved with a payback period of only 9 months. These savings could be achieved by implementing a setback control strategy with an improved time management procedure. Predicting the impact of failing equipment is a difficult task because of the integrated dynamic effect every HVAC component has on the next. With the aid of a comprehensive integrated simulation model the implications of failing can be determined and necessary assessments and precautions can be taken. The results of this study showed that the air-conditioning system under investigation was approximately 100% over designed. Failure of up to 50% was allowable in the cooling equipment before any noticeable impact could be observed in the indoor climate. With further failure the required comfort conditions could not be sustained. Dissertation (MSc (Mechanical Engineering))--University of Pretoria, 2006.
Mechanical and Aeronautical Engineering
unrestricted
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Lin, Hong-Jun, and 林宏駿. "A Study of the Natural Ventilation Efficiency of different Windows in the Primary School Gymnasium by Numerical Simulation." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/95544196451208208482.
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碩士樹德科技大學
建築與室內設計研究所
104
Because of should be the future trend of energy scarcity, as well as the earth''s greenhouse effect caused by the global warming phenomenon, earth sustainable concept is basic and important topic, to sustainable development and effective energy saving as the premise, "ventilation" is a very critical issue, I in the school gymnasium to the ventilation type mining to natural ventilation and mechanical ventilation and mixed ventilation design. In this research, the computer simulation of fluid mechanics is used to study the effect of the indoor air flow field in the National Stadium. Refers to the domestic and foreign existing building natural ventilation design and computer simulation analysis of the related research done as the theoretical basis, in order to ensure the reliability and accuracy of the numerical simulation, the simulation of the actual situation of the space we measured data, measured with the Ministry of education sustainable campus local modification of the program, select the application to the school gymnasium transformation of natural ventilation technique. Data results are analyzed and compared with the CFD numerical simulation. The simulation results of the indoor air flow field and temperature field are analyzed by CFD numerical simulation, and the computer is used to analyze the indoor environment. Analysis and comparison of different ventilation types and specifications, and according to the results of this paper provide the reference and suggestion for the design and planning of the gymnasium in the future.
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Arndt, D. C. "Integrated dynamic simulation of large thermal systems." Thesis, 2001. http://hdl.handle.net/2263/26065.
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Studies concluded that more that 10% of all energy consumed in the world is expended by building air-conditioning systems. Energy efficiency in building and HVAC (Heating, Ventilating and Air-conditioning) design is therefore exceptionally important. A cost¬-effective way to improve the energy efficiency of a HV AC system, without compromising indoor comfort, is by implementing better control. System energy cost savings of up to 50% can be realised by optimising the system operating control strategies with direct payback periods of less than a year. However, when changing the operating strategy of a system it is often difficult to predict the resulting changes in system energy consumption and indoor comfort. To achieve these predictions, a dynamic simulation tool, which can efficiently and accurately simulate the building with the HV AC and control system in an integrated fashion, is required. Extensions to the integrated tool QUICKcontrol is therefore proposed to suite the needs of the energy service contractor. QUICKcontrol still has many shortcomings in the availability of component models for certain equipment commonly used in building systems today. New dynamic component models were therefore derived in this study. The accuracy and applicability of integrated building and natural ventilation modelling is illustrated in animal housing facilities. The predicted results obtained during this study were satisfactory to use these models with confidence in this type of building applications. The applicability of building, HV AC system and control simulations was illustrated in conference facilities. The results obtained show the value of integrated building and system simulation in the evaluation of energy cost saving inventions in commercial buildings. The mining and industrial sectors in South Africa consume about 40% of ESKOM's total electrical energy production. Mines alone use nearly 20% of the electricity provided by ESKOM. Ventilation and cooling (VC) systems are responsible for approximately 25% or R750 million of this energy. It will therefore be beneficial if the mines can be more energy clever in order to reduce their VC operating costs. The use of an extended integrated building and system simulation tool was therefore realised to investigate the potential for energy cost savings in mine VC applications. To extend QUICKcontrol for the simulation of other large thermal systems found in mining and industrial applications, new component models and simulations procedures were developed. Two case studies were performed with the extended tool to illustrate its applicability in thermal systems other than building systems. The potential for Demand Side Management (DSM) on a surface cooling plant and an underground clear water-pumping system was investigated. Satisfactory results were obtained during the two investigations to utilise this extended tool with confidence in practice. With more extensions to the tool it should be possible to investigate the potential for energy cost saving on any other thermal industrial applications.Thesis (PhD (Mechanical Engineering))--University of Pretoria, 2007.
Mechanical and Aeronautical Engineering
unrestricted
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wei-liang, Tseng, and 曾維良. "A Study on Atrium Natural Ventilation Efficiency of the Separate Open Model by CFD Simulation- Case study of Taipei city Hall Atrium." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/97230050605470955035.
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碩士淡江大學
建築學系
91
Taipei located in north part of Taiwan. It is subtropical climate with clear four seasons. The climate in architecture belongs to sub-heat & moist. The average relative humidity more than 80%. The first priority of architectural design in this area is to prevent moist, dew & ventilation. However, the current business building design seldom implement natural ventilation but with air conditioner. It exhaust natural resources of the earth gradually if solely depends on air conditioner. The air will deteriorate below to live standard swiftly when power failure. Taipei is the Capital of Taiwan. It goes without saying that the importance to politics, economic. The movement of Taipei influences the trend of other place in Taiwan. So, the Taipei City Hall not only the central nervous of public works of Taipei City but also demonstrate to society. On economic, reconstruction creates benefit of essence application. On the other hand, the benefit couldn’t be counted as a demonstration to society & environment. The Case study of Taipei City Hall Atrium. To analyze the factor of climate of Taipei including wind velocity, wind direction, temperature & humidity for the latest 10 years to obtain the months that suit natural ventilation. The natural ventilation based on temperature 21.52。C, wind velocity 3.0m/s. To use CFD Simulation to probe into the interrelation between opening mode and ventilate efficiency. We expect to find a better way of opening through the case study to provide reference for prospective designer & user. The Administration of Taipei City costs approximately $251,300 monthly on the ventilation in atrium. The cost to modify skylight of atrium about $3,466,050. That is to say, total reconstruction expense can be shared in 14 months.
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Liao, Ker-Hsun, and 廖克勳. "Applications of STAR-CD on Simulation of Flow Field Inside an Exhaust Chamber of a Scroll Compressor and the Ventilation Efficiency in ZPRL Building." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/40137558858079878928.
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碩士國立交通大學
機械工程系
88
This thesis utilizes a commercial code, SATR-CD, to simulate the flow field for two subjects. The first one is the flow field inside an exhaust chamber of a scroll compressor, the other is the ventilation flow inside a building of ZPRL (Zero Power Reactor at Lungtan). The computed results of the first part show that the refrigerant from discharge port enters the exhaust chamber, and the center of top cover becomes the high-pressure area due to the main flow direct impingement. After that, it flows out the chamber through the exhaust pipe. If a check valve is placed in the chamber, then, the main stream will directly impinge its top surface, resulting in a high pressure inside the check valve. The stream then flows out the check valve to the exhaust chamber. Not subjected to the flow impingement directly, the pressure of top cover becomes lower and its distribution more uniform. Finally, a successive flow variation history can be observed by an animation by using the transient flow simulation of STAR-CD. In the second part, the simulation results find that there exist many small vortices at corners in the building for its original design. After three additional experimental rooms are set up in the original building, the space of flow path is limited. Therefore, the re-circulation flows are occurred at the corners and wall surfaces along these additional experiment rooms. The velocities of flow are slightly decreased accordingly. The flow velocities in the third floor are found relatively small and its pressure distribution becomes more uniform. Comparing the results obtained from the four case studies, it can be concluded that the arrangement of space has a much greater influence on the flow structure than that of the total ventilation flow rate in the range of 5000 to 10000 cfm.
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Oucherfi, Myriam. "Contribution à l’étude de la ventilation transversale lors d’un incendie en tunnel routier." Thesis, 2009. http://www.theses.fr/2009LYO10037/document.
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L’objectif de cette thèse est de présenter des critères simples pour l’évaluation des performances d’une ventilation transversale. On définit l’efficacité et le rendement, calculés à partir du flux de déficit de densité créé par l’incendie. Après une étude préliminaire permettant de caler les modèles numériques, l’influence de différents paramètres sur ces valeurs a été évaluée. Dans un premier temps, l’étude a porté sur une seule trappe et a montré que le courant d’air dans le tunnel est le paramètre le plus important. A l’inverse, la forme de la trappe pour une surface donnée n’a que très peu d’importance, sauf dans des cas limites (fente sur toute la largeur du tunnel). L’étude d’un canton à huit trappes confirme l’importance du contrôle du courant d’air. Lorsqu’on diminue le nombre de trappes en conservant la même surface totale d’aspiration, cette sensibilité tend à disparaître, mais l’efficacité diminue. Enfin, l’étude de l’influence de l’encombrement montre une légère amélioration de l’efficacité, due à l’obstruction d’une partie de la section par des camions, qui bloquent les fumées au droit des trappesThe aim of this study is to present simple criteria to evaluate the performances of a transverse ventilation system. Efficiency and yield have been defined, based on the flux of density deficit createdby the fire. After a preliminary study of numerical models, the influence of different parameters on those criteria has been investigated. First, the study focused on the simplified case of a single damper. We showed that the air flow speed in the tunnel is the more important parameter. On the contrary, the shape of the damper has little influence on the efficency, except in unusual cases (slit on the whole width of the tunnel). Then, the study of a longer portion of the tunnel confirmed the prominence of the limitation of air flow speed. Comparison with a case with fewer dampers but the same total extraction section showed that this sensibility to air flow speed tends to disappear for larger dampers, but that the efficiency is lowered. Finally the study of the influence of heavy-goods-vehicules obstructing the tunnel reports better results, due to the fact that big objects tend to confine smokes
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Khatib, Akram Ghassan. "Evaluation of performance of an air handling unit using wireless monitoring system and modeling." Thesis, 2014. http://hdl.handle.net/1805/5943.
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Indiana University-Purdue University Indianapolis (IUPUI)Heating, ventilation, and air conditioning (HVAC) is the technology responsible to maintain temperature levels and air quality in buildings to certain standards. In a commercial setting, HVAC systems accounted for more than 50% of the total energy cost of the building in 2013 [13]. New control methods are always being worked on to improve the effectiveness and efficiency of the system. These control systems include model predictive control (MPC), evolutionary algorithm (EA), evolutionary programming (EP), and proportional-integral-derivative (PID) controllers. Such control tools are used on new HVAC system to ensure the ultimate efficiency and ensure the comfort of occupants. However, there is a need for a system that can monitor the energy performance of the HVAC system and ensure that it is operating in its optimal operation and controlled as expected. In this thesis, an air handling unit (AHU) of an HVAC system was modeled to analyze its performance using real data collected from an operating AHU using a wireless monitoring system. The purpose was to monitor the AHU's performance, analyze its key parameters to identify flaws, and evaluate the energy waste. This system will provide the maintenance personnel to key information to them to act for increasing energy efficiency. The mechanical model was experimentally validated first. Them a baseline operating condition was established. Finally, the system under extreme weather conditions was evaluated. The AHU's subsystem performance, the energy consumption and the potential wastes were monitored and quantified. The developed system was able to constantly monitor the system and report to the maintenance personnel the information they need. I can be used to identify energy savings opportunities due to controls malfunction. Implementation of this system will provide the system's key performance indicators, offer feedback for adjustment of control strategies, and identify the potential savings. To further verify the capabilities of the model, a case study was performed on an air handling unit on campus for a three month monitoring period. According to the mechanical model, a total of 63,455 kWh can be potentially saved on the unit by adjusting controls. In addition the mechanical model was able to identify other energy savings opportunities due to set point changes that may result in a total of 77,141 kWh.
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Barešová, Lenka. "Využití zážitkové pedagogiky a dramatické výchovy ve výuce zeměpisu na střední škole." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-310384.
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The main objective of the thesies is to compare a frontal teaching method and teaching by simulation. Two comparable groups of students were taught the same topic by the two methods. The topic was focused on an uneven world development. Following assumptions were set. Simulation is a more attractive teaching form, therefore it can help to raise the motivation of students. Frontal method is capable of transmitting more information. Simulation, however, can have bigger impact on students' values. The impact of simulation has a long-term impact in comparison to frontal teaching. These assumptions were confirmed by qualitative and quantitative methods.