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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Energy Management in Large scale Solar Buildings : The Closed Greenhouse Concept

Vadiee, Amir January 2013 (has links)
Sustainability has been at the centre of global attention for decades. One of the most challenging areas toward sustainability is the agricultural sector. Here, the commercial greenhouse is one of the most effective cultivation methods with a yield per cultivated area up to 10 times higher than for open land farming. However, this improvement comes with a higher energy demand. Therefore, the significance of energy conservation and management in the commercial greenhouse has been emphasized to enable cost efficient crop production. This Doctoral Thesis presents an assessment of energy pathways for improved greenhouse performance by reducing the direct energy inputs and by conserving energy throughout the system. A reference theoretical model for analyzing the energy performance of a greenhouse has been developed using TRNSYS. This model is verified using real data from a conventional greenhouse in Stockholm (Ulriksdal). With this, a number of energy saving opportunities (e.g. double glazing) were assessed one by one with regards to the impact on the annual heating, cooling and electricity demand. Later, a multidimensional energy saving method, the “Closed Greenhouse”, was introduced. The closed greenhouse is an innovative concept with a combination of many energy saving opportunities. In the ideal closed greenhouse configuration, there are no ventilation windows, and the excess heat, in both sensible and latent forms, needs to be stored using a seasonal thermal energy storage. A short term (daily) storage can be used to eliminate the daily mismatch in the heating and cooling demand as well as handling the hourly fluctuations in the demand. The key conclusion form this work is that the innovative concept “closed greenhouse” can be cost-effective, independent of fossil fuel and technically feasible regardless of climate condition. For the Nordic climate case of Sweden, more than 800 GWh can be saved annually, by converting all conventional greenhouses into this concept. Climate change mitigation will follow, as a key impact towards sustainability. In more detail, the results show that the annual heating demand in an ideal closed greenhouse can be reduced to 60 kWhm-2 as compared to 300 kWhm-2 in the conventional greenhouse. However, by considering semi-closed or partly closed greenhouse concepts, practical implementation appears advantageous. The required external energy input for heating purpose can still be reduced by 25% to 75% depending on the fraction of closed area. The payback period time for the investment in a closed greenhouse varies between 5 and 8 years depending on the thermal energy storage design conditions. Thus, the closed greenhouse concept has the potential to be cost effective. Following these results, energy management pathways have been examined based on the proposed thermo-economic assessment. From this, it is clear that the main differences between the suggested scenarios are the type of energy source, as well as the cooling and dehumidification strategies judged feasible, and that these are very much dependent on the climatic conditions Finally, by proposing the “solar blind” concept as an active system, the surplus solar radiation can be absorbed by PVT panels and stored in thermal energy storage for supplying a portion of the greenhouse heating demand. In this concept, the annual external energy input for heating purpose in a commercial closed greenhouse with solar blind is reduced by 80%, down to 62 kWhm-2 (per unit of greenhouse area), as compared to a conventional configuration. Also the annual total useful heat gain and electricity generation, per unit of greenhouse area, by the solar blind in this concept is around 20 kWhm-2 and 80 kWhm-2, respectively. The generated electricity can be used for supplying the greenhouse power demand for artificial lighting and other devices. Typically, the electricity demand for a commercial greenhouse is about 170 kWhm-2. Here, the effect of “shading” on the crop yield is not considered, and would have to be carefully assessed in each case. / Hållbarhet har legat i fokus under decennier. En av de mest utmanande områdena är jordbrukssektorn, där. kommersiella växthus är ett av de mest effektiva odlingsalternativen med en avkastning per odlad yta upp till 10 gånger högre än för jordbruk på friland. Dock kommer denna förbättring med ett högre energibehov. Därför är energieffektivisering i kommersiella växthus viktig för att möjliggöra kostnadseffektiv odling. Denna doktorsavhandling presenterar en utvärdering av olika energiscenarios för förbättring av växthusens prestanda genom att minska extern energitillförsel och spara energi genom i systemet som helhet. För studien har en teoretisk modell för analys av energiprestanda i ett växthus utvecklats med hjälp av TRNSYS. Denna modell har verifierats med hjälp av verkliga data från ett konventionellt växthus i Stockholm (Ulriksdal). Med denna modell har ett antal energibesparingsåtgärder (som dubbelglas) bedömts med hänsyn till de totala värme-, kyl-och elbehoven. En flerdimensionell metod för energibesparing, det s.k. "slutna växthuset", introduceras. Det slutna växthuset är ett innovativt koncept som är en kombination av flera energibesparingsmöjligheter. I den ideala slutna växthuskonfigurationen finns det inga ventilationsfönster och värmeöverskott, både sensibel och latent, lagras i ett energilager för senare användning. Daglig lagring kan användas för att eliminera den dagliga obalansen i värme-och kylbehovet. Ett säsongslager introduceras för att möjliggöra användandet av sommarvärme för uppvärmning vintertid. Den viktigaste slutsatsen från detta arbete är att ett sådant innovativt koncept, det "slutna växthuset" kan vara kostnadseffektiv, oberoende av fossila bränslen och tekniskt genomförbart oavsett klimatförhållanden. För det svenska klimatet kan mer än 800 GWh sparas årligen, genom att konvertera alla vanliga växthus till detta koncept. Det årliga värmebehovet i ett idealiskt slutet växthus kan reduceras till 60 kWhm-2 jämfört med 300 kWhm-2 i ett konventionellt växthus. Energibesparingen kommer även att minska miljöpåverkan. Även ett delvis slutet växthus, där en del av ytan är slutet, eller där viss kontrollerad ventilation medges, minskar energibehovet samtidigt som praktiska fördelar har kunnat påvisas. Ett delvis slutet växthus kan minska energibehovet för uppvärmning med mellan 25% och 75% beroende på andelen sluten yta. En framräknad återbetalningstid för investeringen i ett slutet växthus varierar mellan 5 och 8 år beroende på design av energilagringssystemet. Sålunda har det slutna växthuskonceptet potential att vara kostnadseffektiv. Mot bakgrund av dessa lovande resultat har sedan scenarios för energy management analyserats med hänsyn till termo-ekonomiska faktorer. Från detta är det tydligt att de viktigaste skillnaderna mellan de föreslagna scenarierna är den typ av energikälla, samt kyl- och avfuktningsstrategier som används, och dessa val är mycket beroende av klimatförhållandena. Slutligen, föreslås ett nytt koncept, en s.k. "solpersienn", vilket är ett aktivt system där överskottet av solstrålningen absorberas av PVT-paneler och lagras i termiskenergilager för att tillföra en del av växthuseffekten värmebehov. I detta koncept minskar den årliga externa energitillförseln för uppvärmning i ett slutet växthus med 80%, ner till 62 kWhm-2. Den totala värme- och elproduktionen, med konceptet "solpersienn" blir cirka 20 kWhm-2 respektive 80 kWhm-2. Elproduktion kan användas för artificiell belysning och annan elektrisk utrustning i växthuset. / <p>QC 20130910</p>
122

Optimisation des engins de pêche en terme d'économie de carburant / Optimization of fishing gear in terms of fuel consumption

Khaled, Ramez 30 April 2012 (has links)
L'industrie de la pêche est confrontée à plusieurs contraintes comme l'augmentation du prix du carburant et la diminution des stocks de poisson. Pour améliorer la rentabilité, nous avons fait l'optimisation des chaluts de pêche (pélagique et de fond) afin d'augmenter leurs efficacités énergétiques. Deux facteurs principaux ont été utilisés : la traînée du chalut et sa surface balayée. Notre travail porte sur l'optimisation du plan du chalut par modification du nombre de mailles des pièces du filet et par changement de la longueur des câbles. Nous avons développé une méthode de recherche successive appelée SOT et nous l'avons comparée à une méthode de recherche aléatoire dans le cas d'un chalut pélagique avec un gain net de 54%. La SOT a été utilisée pour optimiser le plan des pièces du filet d'un chalut de fond. Une amélioration du gain énergétique de 38% a été obtenue, ainsi qu'une réduction de 45 jours de pêche. Par souci de risque de baisse de capturabilité, nous avons développé une fonction objectif qui dépend de la distribution de poisson. Trois fonctions de même densité surfacique ont été testées. L'amélioration de l'efficacité énergétique calculée par la méthode SOT sur un chalut de fond est respectivement de 52%, 16% et 32% selon les trois distributions. Avec la méthode SRT (méthode de raffinement séquentiel), nous obtenons des réductions de 56%, 30% et 39% pour les trois distributions. Finalement nous avons adapté la méthode SOT pour optimiser les longueurs des câbles du chalut. Nous obtenons dans un cas une amélioration de l'efficacité énergétique de 49%. L'utilité de ce travail devrait être étendue hors de la pêche comme l'écologie en général. / Nowadays, fishing industry is facing several constraints such as increased fuel prices and declining fish stocks. In this work, we perform optimization of fishing trawls (pelagic and bottom) in order to improve their energy efficiencies. Two main factors were used: the trawl drag and its mouth swept area. Our work focuses on optimizing trawl design by altering mesh numbers and changing cable length. We have developed a method called SOT and compared it to a random search method in the pelagic trawl case with a net energy gain of 54%. The SOT was used in design optimization of bottom trawl panels. Improved energy gain of 38% was obtained and a reduction of 45 total number of fishing days. In order to bypass catchability reduction, we developed an objective function which depends on fish distribution. Three functions with same bottom surface density were tested. Improving energy efficiency calculated by the SOT method on a bottom trawl is respectively 52%, 16% and 32% for the three distributions. With the SRT method (sequential refinement), we obtain reductions of 56%, 30% and 39% for the three aforementioned distributions. Finally we adapted the SOT method to optimize trawl cable lengths. In one case, we obtain energy efficiency improved by 49%. The usefulness of this work should be extended beyond fishery to ecology in general.
123

Kategorisering och energikartläggning av flerbostadshus byggda 1945 eller tidigare : En analys av energieffektiviseringspotentialen hos historiska byggnader i Vasastaden, Linköping / Categorizing and energy audit of apartment buildings constructed 1945 or earlier : An analysis of energy saving potential in historic buidlings in Vasastaden, Linköping

Wahlgren, Johannes, Kraft, Billy January 2019 (has links)
With the increased energy usage and its affect on the environment the European Union (EU) has issued climate and environment goals which will oversee countries energy saving potential. These goals focus on several areas including the energy usage within buildings. The purpose of this thesis is to categorize and analyze the energy saving potential for buildings constructed 1945 or earlier. The building stock in focus consists of 73 apartment buildings in Vasastaden, Linköping. The buildings were all chosen with Boverket’s database within building characteristics GRIPEN. The method consisted of stocktaking via location visits, categorizing and performing simulations on the buildings. The fictive buildings were based on the categorized building stock. They were modelled and simulated with the help of IDA Indoor Climate and Energy (IDA ICE). With the results of the energy usage a greater understanding of energy saving potential was obtained. The result of the categorization displayed that typical buildings in Vasastaden are buildings out of brick, fully detached (no adjoining walls), specifically with 3 floors. The fictive buildings have an calculated energy usage of 102-144 kWh/m2,year and have an energy saving potential within ranges of 17-41% compared to the building regulations set by Boverket (BBR). The building stock obtained an calculated energy usage of 804-3 515 MWh/m2,year. GRIPEN displayed several inaccuracies compared with the collected data from the location visits which proves that more frequent updates in databases such as GRIPEN are of high significance.
124

Análise da resposta da demanda e da geração distribuída fotovoltaica como recursos para o planejamento energético. / Analysis of demand response and photovoltaic distributed generation as resources for energy planning.

Viana, Matheus Sabino 04 October 2018 (has links)
Este estudo analisa a Resposta da Demanda (DR da sigla em inglês para Demand Response) e a Geração Distribuída Fotovoltaica (GDFV), visando o desenvolvimento de uma abordagem para modelá-las como recursos para o planejamento energético. A metodologia inclui o uso de uma prática típica de preço de energia no varejo como a Tarifa pelo Horário de Uso (THU) para DR de consumidores residenciais e o sistema de compensação de energia elétrica (net metering) para a microgeração distribuída provida por sistemas Fotovoltaicos (FV) do tipo rooftop. A metodologia proposta foi aplicada a um estudo de caso com diferentes níveis de DR e/ou GDFV, baseado no IEEE 8500-Node Test Feeder, com uma subestação de distribuição e 1177 consumidores em baixa tensão, utilizando-se o Open Distribution System Simulator (OpenDSS) para a solução do fluxo de potência e a obtenção de dados de demanda, consumo de energia, perdas e tensões. Os níveis mais elevados de DR e GDFV, em dia útil, em um grupo de Consumidores Residenciais Responsivos (CRR) cuja carga representa 26,6% da carga total do circuito de teste, resultaram em 6,3% de redução na demanda de ponta da subestação, 9,6% de redução no consumo diário de energia da subestação e 13,3% de redução nas perdas diárias de energia nas linhas e transformadores, comparando-se com o caso base com a tarifa convencional, sem DR e GDFV, e mantendo-se o consumo diário de energia dos CRR. Uma análise de sensibilidade foi realizada por meio de variações aleatórias nas curvas de carga dos consumidores e, nos cenários aplicáveis, na irradiância no plano inclinado e na temperatura dos conjuntos FV, respeitando uma distribuição normal. O estudo de caso foi complementado com a avaliação das variações na conta de energia de amostras de CRR, cujas maiores reduções, comparando-se com o caso base, foram 36,3% com os níveis mais elevados de DR e GDFV e 37,6% com os níveis mais elevados de GDFV e sem DR, indicando uma situação na qual mudanças regulatórias seriam necessárias para estimular DR e GD simultaneamente, como no caso da THU opcional chamada de tarifa branca no Brasil. A quantificação do potencial de DR e GDFV pode indicar tendências para o planejamento energético, contribuir para planos de eficiência energética e possibilitar a implementação de sistemas modernos e sustentáveis nos quais os consumidores possam participar de forma mais ativa. / This study analyses the Demand Response (DR) and Photovoltaic Distributed Generation (PVDG) for developing an approach to model them as resources for energy planning. The methodology includes the use of a typical retail pricing practice such as the Time-of-Use Tariff (TOU) for residential consumers\' DR and net metering for distributed micro-generation provided by rooftop Photovoltaic (PV) systems. The proposed methodology was applied to a case study with different levels of DR and/or PVDG, based on the IEEE 8500-Node Test Feeder, with a distribution substation and 1177 low-voltage consumers, using the Open Distribution System Simulator (OpenDSS) to obtain the power flow solution and demand, energy consumption, losses and voltages data. The highest levels of DR and PVDG on weekday in a group of Responsive Residential Consumers (RRC) whose load represents 26.6% of the total load in the test circuit resulted in 6.3% reduction in the substation peak demand, 9.6% reduction in the substation daily energy consumption and 13.3% reduction in the daily energy losses in lines and transformers, compared to the base case with flat tariff, without DR and PVDG, and maintaining the daily energy consumption of RRC. A sensitivity analysis was performed using random variations in load curves and, in the applicable scenarios, in plane-of-array irradiance and PV array temperature curves, using a normal distribution. The case study was complemented with the analysis of energy bill variations of samples of RRC, whose greatest reductions compared to the base case were 36.3% with the highest levels of DR and PVDG and 37.6% with the highest level of PVDG and without DR, indicating a situation in which regulatory changes would be necessary to stimulate DR simultaneously with PVDG, such as in the case of the optional TOU called white tariff in Brazil. The quantification of DR and PVDG potential can show trends to energy planning, contributes to energy efficiency plans and enables the implementation of modern and sustainable systems in which end users can participate more actively.
125

Economia de energia elétrica em ambientes inteligentes baseada no reconhecimento de atividades do usuário

Lima, Wesllen Sousa 05 March 2015 (has links)
Submitted by Kamila Costa (kamilavasconceloscosta@gmail.com) on 2015-06-11T20:40:36Z No. of bitstreams: 1 Dissertação-Wesllen S Lima.pdf: 2617450 bytes, checksum: 12694bdd075a47f1778193c5500476be (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-15T18:09:11Z (GMT) No. of bitstreams: 1 Dissertação-Wesllen S Lima.pdf: 2617450 bytes, checksum: 12694bdd075a47f1778193c5500476be (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-15T18:10:18Z (GMT) No. of bitstreams: 1 Dissertação-Wesllen S Lima.pdf: 2617450 bytes, checksum: 12694bdd075a47f1778193c5500476be (MD5) / Made available in DSpace on 2015-06-15T18:10:18Z (GMT). No. of bitstreams: 1 Dissertação-Wesllen S Lima.pdf: 2617450 bytes, checksum: 12694bdd075a47f1778193c5500476be (MD5) Previous issue date: 2015-03-05 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In recent years, power consumption has gradually increased in all sectors, especially in residential areas. This increase is mainly due to the emergence of new electrical appliances, for this reason, several solutions have been proposed by government and industry in order to minimize the energy consumption in homes. Among the proposed approaches, people's awareness, use of renewable energy sources and the creation of intelligent devices are highlighted . In addition, the use of Information and Communication Technologies (ICTs) in smart environments has been seen as an interesting alternative to deal with this problem. The idea is that the residences are instrumented with sensors and actuators in order to monitor people activities and, thereby, manage the power consumption based on their habits. In this context, this work proposes and validates a method to save energy through user activities in an intelligent environment using artificial intelligence techniques. The goal is to identify the devices related to user activities and make recommendations during their execution, avoiding waste. The proposed method, called AAEC (Activity-Appliance-Energy Consumption), is able to analyze a set of data collected from sensors available in the environment, after it recognizes user activities and recommends actions aimed at cost containment. Tests on a real database shown that the proposed method is able to save up to 35% of electricity. In general, the inclusion of AAEC method was a good solution to help people save energy without effort on individual behavior changes, contributing to the conscious use of energy and to the development of a sustainable society. / Nos últimos anos, o consumo de energia elétrica tem aumentado gradativamente em todos os setores, especialmente em ambientes residenciais. Esse aumento ocorre, principalmente, devido ao surgimento de novos aparelhos elétricos. Por este motivo, várias soluções têm sido propostas pelo governo e pela indústria na tentativa de minimizar o consumo de energia elétrica em residências. Dentre as abordagens propostas, destacam-se a conscientização das pessoas, uso de fontes de energia renováveis e a criação de aparelhos inteligentes. Além disso, o uso de Tecnologias da Informação e Comunicação (TICs) em ambientes inteligentes tem sido visto como uma alternativa interessante para lidar com este problema. A ideia é que as residências sejam instrumentadas com sensores e atuadores com objetivo de monitorar as atividades das pessoas e, por meio disso, gerenciar o consumo de energia elétrica com base nos seus hábitos. Nesse contexto, este trabalho propõe e valida um método capaz de economizar energia com base nas atividades dos usuários em um ambiente inteligente utilizando técnicas de inteligência artificial. O objetivo é identificar os aparelhos relacionados às atividades dos usuários e fazer recomendações ao longo da execução dessas atividades, evitando tais desperdícios. O método proposto, denominado de AAEC (Activity-Appliance-Energy Consumption), é capaz de analisar um conjunto de dados coletados pelos sensores disponíveis no ambiente, reconhecer automaticamente as atividades dos usuários e recomendar ações que visam a contenção de gastos. Testes feitos com uma base de dados real mostram que o método proposto é capaz de economizar até 35% de energia elétrica. De maneira geral, a inclusão do método AAEC se mostrou uma boa solução para auxiliar as pessoas a poupar energia sem que haja esforço na mudança de comportamento do indivíduo, contribuindo para o uso consciente de energia e no desenvolvimento de uma sociedade sustentável.
126

Análise da resposta da demanda e da geração distribuída fotovoltaica como recursos para o planejamento energético. / Analysis of demand response and photovoltaic distributed generation as resources for energy planning.

Matheus Sabino Viana 04 October 2018 (has links)
Este estudo analisa a Resposta da Demanda (DR da sigla em inglês para Demand Response) e a Geração Distribuída Fotovoltaica (GDFV), visando o desenvolvimento de uma abordagem para modelá-las como recursos para o planejamento energético. A metodologia inclui o uso de uma prática típica de preço de energia no varejo como a Tarifa pelo Horário de Uso (THU) para DR de consumidores residenciais e o sistema de compensação de energia elétrica (net metering) para a microgeração distribuída provida por sistemas Fotovoltaicos (FV) do tipo rooftop. A metodologia proposta foi aplicada a um estudo de caso com diferentes níveis de DR e/ou GDFV, baseado no IEEE 8500-Node Test Feeder, com uma subestação de distribuição e 1177 consumidores em baixa tensão, utilizando-se o Open Distribution System Simulator (OpenDSS) para a solução do fluxo de potência e a obtenção de dados de demanda, consumo de energia, perdas e tensões. Os níveis mais elevados de DR e GDFV, em dia útil, em um grupo de Consumidores Residenciais Responsivos (CRR) cuja carga representa 26,6% da carga total do circuito de teste, resultaram em 6,3% de redução na demanda de ponta da subestação, 9,6% de redução no consumo diário de energia da subestação e 13,3% de redução nas perdas diárias de energia nas linhas e transformadores, comparando-se com o caso base com a tarifa convencional, sem DR e GDFV, e mantendo-se o consumo diário de energia dos CRR. Uma análise de sensibilidade foi realizada por meio de variações aleatórias nas curvas de carga dos consumidores e, nos cenários aplicáveis, na irradiância no plano inclinado e na temperatura dos conjuntos FV, respeitando uma distribuição normal. O estudo de caso foi complementado com a avaliação das variações na conta de energia de amostras de CRR, cujas maiores reduções, comparando-se com o caso base, foram 36,3% com os níveis mais elevados de DR e GDFV e 37,6% com os níveis mais elevados de GDFV e sem DR, indicando uma situação na qual mudanças regulatórias seriam necessárias para estimular DR e GD simultaneamente, como no caso da THU opcional chamada de tarifa branca no Brasil. A quantificação do potencial de DR e GDFV pode indicar tendências para o planejamento energético, contribuir para planos de eficiência energética e possibilitar a implementação de sistemas modernos e sustentáveis nos quais os consumidores possam participar de forma mais ativa. / This study analyses the Demand Response (DR) and Photovoltaic Distributed Generation (PVDG) for developing an approach to model them as resources for energy planning. The methodology includes the use of a typical retail pricing practice such as the Time-of-Use Tariff (TOU) for residential consumers\' DR and net metering for distributed micro-generation provided by rooftop Photovoltaic (PV) systems. The proposed methodology was applied to a case study with different levels of DR and/or PVDG, based on the IEEE 8500-Node Test Feeder, with a distribution substation and 1177 low-voltage consumers, using the Open Distribution System Simulator (OpenDSS) to obtain the power flow solution and demand, energy consumption, losses and voltages data. The highest levels of DR and PVDG on weekday in a group of Responsive Residential Consumers (RRC) whose load represents 26.6% of the total load in the test circuit resulted in 6.3% reduction in the substation peak demand, 9.6% reduction in the substation daily energy consumption and 13.3% reduction in the daily energy losses in lines and transformers, compared to the base case with flat tariff, without DR and PVDG, and maintaining the daily energy consumption of RRC. A sensitivity analysis was performed using random variations in load curves and, in the applicable scenarios, in plane-of-array irradiance and PV array temperature curves, using a normal distribution. The case study was complemented with the analysis of energy bill variations of samples of RRC, whose greatest reductions compared to the base case were 36.3% with the highest levels of DR and PVDG and 37.6% with the highest level of PVDG and without DR, indicating a situation in which regulatory changes would be necessary to stimulate DR simultaneously with PVDG, such as in the case of the optional TOU called white tariff in Brazil. The quantification of DR and PVDG potential can show trends to energy planning, contributes to energy efficiency plans and enables the implementation of modern and sustainable systems in which end users can participate more actively.
127

Adapter les modèles de chauffage et climatisation des bâtiments en puissance à l'échelle du quartier / Adapting buildings heating and cooling power need models at the district scale

Frayssinet, Loïc 26 October 2018 (has links)
Les modèles énergétiques des bâtiments à l’échelle du quartier sont généralement simplifiés pour faire face au manque de données et pour réduire le coût de calcul. Cependant, l’impact de ces simplifications sur la validité des modèles n’est pas systématiquement analysée, en particulier lorsqu’on s’intéresse à la courbe de charge. Pour combler ce manque, une méthodologie permettant de quantifier la validité des simplifications, notamment vis-à-vis de la courbe de charge, est proposée. Cette méthodologie est appliquée aux simplifications couramment utilisée pour les modèles thermiques d’enveloppe de bâtiments grâce à une plateforme numérique développée dans le cadre de cette thèse. Cette plateforme permet de générer et simuler automatiquement des modèles énergétiques de bâtiments, avec différents niveaux de détails, à partir de données issues de systèmes d’information géographique. La parallélisation des simulations énergétiques des bâtiments est utilisée à l’échelle du quartier, afin de tirer avantage de la structure du modèle global et de réduire les temps de calculs. La définition d’indicateurs spécifiques selon l’objectif de simulation apparait clairement comme l’étape essentielle lorsque l’on s’intéresse à la courbe de charge. Les résultats indiquent que la puissance est plus sensible aux simplifications que la consommation annuelle d’énergie. Les différents effets induits sont quantifiés et analysés physiquement. La capacité de l’échelle du quartier à atténuer les impacts des simplifications et d’intégrer les données statistiques est démontrée. La quantification des impacts des simplifications permet de guider l’adaptation des modèles vis-à-vis des objectifs de simulation et vis-à-vis des contraintes techniques. Cette contribution a pour objectif d’améliorer la performance des simulations énergétiques à l’échelle de la ville, et de favoriser leur développement, afin de répondre aux enjeux futurs. / District-scale building energy models are generally simplified to cope with a lack of data and to reduce computational cost. However, the impacts of these simplifications on model accuracy are not systematically studied, particularly when considering power demand. The present manuscript introduces a methodology to determine the suitability of any simplifications, notably those at the district scale, and considering the power demand. This methodology was applied to usual simplifications of the building envelope model thanks to a specific platform developed in the frame of this thesis. This platform enables automatically generating and simulating building energy models with different modelling levels of detail from geographical information systems. The parallelisation of the building energy simulations was notably implemented at the district scale in order to benefit from the model structure and to efficiently reduce the computational duration. The definition of indicators related to specific simulation objectives appears to be a necessary step when focusing on power demand. The results show a higher sensitivity to simplifications of the power demand than the annual energy consumption. These effects are quantified and physically analysed. The district-scale ability to attenuate the impacts of simplifications and to integrate statistical sources of data were demonstrated. The resulting quantification of the impacts of the simplifications made it possible to guide the adaptations of models to the simulation objectives and to the technical constraints. Such contribution aims to increase the efficiency and to favour the development of city-scale energy simulations, which are particularly needed to cope with future challenges.
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Alternativa isoleringsmaterial : Aerogel inom sjöfarten / Alternative Insulation Materials : Aerogel in shipping

Johansson, Daniel January 2019 (has links)
Detta arbete handlar om att med en teoretisk modell kunna beräkna fram de olika mängder värmeförluster som vissa isoleringsmaterial släpper igenom.  Syftet med detta arbete är att undersöka om ett specifikt isoleringsmaterial som vanligtvis inte används inom sjöfarten har möjligheten att sänka energin som försvinner igenom isoleringsmaterialen. De metoder som användes är en teoretisk modell som byggdes för att  kunna använda de olika isoleringsmaterialens värmekonduktivitet för sedan kunna beräkna de teoretiska värmeförlusterna. Resultatet visar att aerogel skulle vara lämpligt för användning inom sjöfarten tack vara sina egenskaper och isoleringsförmåga som är mycket bättre än mineralull. / This work is about using a theoretical model to calculate the various amounts of thermal losses that some insulation materials release. The purpose of this work is to investigate whether a specific insulation material that has not been properly tested in shipping has the potential to lower energy that passes through the insulation materials. The methods used are that a theoretical model was built to use the thermal conductivity of different insulation materials in order to calculate the theoretical heat losses. The result shows that aerogel would be suitable for use in shipping thanks to its properties and insulation ability, which is much better than mineral wool.
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Exploring the strategies to implement a sustainable energy program in Hong Kong Public Hospitals

Ting, Terry 01 January 2017 (has links)
Healthcare is one of the most energy-intensive industries because of its 24 hour-a-day and 7-days-a-week operation model. Climate change, due to environmental pollution, has increased the incidence of respiratory disease, cardiovascular disease, and cancer, which further overload the financial burden of our healthcare system. The National Health Service Sustainable Development Unit suggested that a sustainable healthcare sector also requires using their resources in an efficient and responsible way. Hong Kong public hospitals are facing this problem along with high energy expenditure. The purpose of this qualitative, multiple site case study was to explore strategies for Hong Kong's public hospital leaders to develop and implement a sustainable program to reduce energy consumption. A purposive sample consisted of five local public hospital leaders that had successfully implemented a sustainable energy at their hospitals and received the 2014 Certificate of Merit of The Hong Kong Awards for Environmental Excellence. Semistructured interviews and document reviews were the data analysis methods for this study. The findings from the data analysis suggested that five major themes arose from the data: (a) external and internal driving forces, (b) leadership, (c) governance, (d) building a sustainable culture, and (e) performance measures. The recommendations of this study may lead to improving the use of energy in an efficient and responsible manner at the local public hospitals, reducing the hospital energy consumption cost, and reducing the disease incidences caused by environmental pollution.
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Illumination properties and energy savings of a solar fiber optic lighting system balanced by artificial lights

Lingfors, David January 2013 (has links)
A solar fiber optic lighting system, SP3 from the Swedish company Parans Solar Lighting AB, has been installed in a study area/corridor test site. A collector is tracking the sun during daytime, focusing the direct sun irradiance via Fresnel lenses into optical fibers, which guide the solar light into the building. The illumination properties of the system have been characterized. The energy saving due to reduced need of artificial lighting have been calculated and methods for balancing the artificial lights in the test site have been evaluated. The illumination at the test site using solar light was at least as high as when using the artificial lights and even higher at very clear days. The luminous flux output (500 lm) was somewhat lower than specified by the manufacturer (550 lm) at 100 000 lx direct sun illuminance. The output at 130 000 lx was high 767±33 lm the sunlight coupling efficiency 23 %. However, for a 20 m SP3 system the luminous flux output (400 lm) at 100 000 lx was higher than specified (350 lm). The SP3 system of Parans provides high quality solar light. It has a fuller spectrum close to the spectrum of the sun compared to the fluorescent lights at the test site. The correlated color temperature of the system was 5800±300 K and the color rendering index 84.9±0.5. The lighting energy saved due to decreased need for artificial light was estimated to 19 % in Uppsala which has 1790 annual sun hours. The savings in Italy, which has 3400 sun hours, is 46 %. Additional saving, especially in warmer countries can be obtained due to decreased need for cooling in the building as the solar luminaires provide negligible heat to the indoor air. Economical saving could also be realized by improved well-being of the occupants spending time under the solar luminaires. Three ways of balancing the artificial light due to sunshine fluctuations have been investigated. The global horizontal irradiance could not be used as a control signal for balancing the artificial lights but a pyranometer attached to the SP3 sun tracking collector was usable. Also the signal from an indoor luxmeter sensor could be used for balancing the light. However the signal from the light sensor which makes the SP3 collector to track the sun is probably the most cost effective method as it would serve two purposes; tracking the sun and balancing the artificial lights.

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