• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 82
  • 39
  • 10
  • 8
  • 6
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 172
  • 172
  • 58
  • 29
  • 28
  • 16
  • 16
  • 16
  • 15
  • 15
  • 15
  • 14
  • 14
  • 14
  • 13
  • 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.
101

Formes urbaines et durabilité du système de transports. : Une application par les coûts de la mobilité urbaine des ménages sur l’agglomération Lyonnaise / Urban forms and sustainability of transport system. : An application to household urban mobility costs within Lyon city

Vanco, Florian 14 April 2011 (has links)
L'objectif de cette thèse est de faire ressortir et d'analyser les facteurs liés à l'organisation spatiale de la population et des activités susceptibles de produire une mobilité plus durable. Sur la base du constat que le système de transports n'est pas durable, nous effectuons une approche par les coûts de la mobilité à partir de trois indicateurs représentatifs de la durabilité de la mobilité des ménages : les coûts annuels de la mobilité urbaine des ménages, le taux d'effort annuel consacré par les ménages pour leurs dépenses de transports et leurs émissions annuelles de CO2. Le lien entre forme urbaine et mobilité n'est pas simple. Il s'agit d'un lien de réciprocité complexe à définir. Les travaux montrent que trois dimensions de l'environnement local jouent au final sur la mobilité des ménages : la densité, la diversité et l'accessibilité. La démarche consiste à confronter les facteurs supposés explicatifs des indicateurs de durabilité de la mobilité des ménages et de déterminer quelle est la part expliquée par la forme urbaine. Sur le périmètre élargi de l'enquête ménages de Lyon (2006), notre approche par les coûts de la mobilité des ménages permet une approche des inégalités sur le plan financier. Par ailleurs, une simulation sur l'évolution des prix du carburant montre que les classes moyennes seront de plus en plus concernées par l'augmentation continue des prix du pétrole à l'avenir. Afin de déterminer la part des coûts de la mobilité expliquée par la forme urbaine, nous bâtissons des modèles explicatifs au niveau du ménage en y intégrant des variables de forme urbaine et variables socio-économique du ménage. L'analyse met aussi en évidence l'influence des pôles secondaires sur la vulnérabilité des ménages et les coûts de la mobilité. Les modèles par type de ménages montrent enfin que les effets de la forme urbaine sont différenciés suivant les types de ménage. Il est également intéressant de mesurer les économies générées par des changements marginaux de forme urbaine. Nous bâtissons pour cela des modèles économétriques à un niveau plus agrégé permettant le calcul de coefficients d'élasticité. En outre nous pouvons estimer en termes économiques les gains espérés suite à des changements de forme urbaine. / The aim of this thesis is to highlight and analyze the factors related to the spatial organization of the population and the economic activities which may produce a more sustainable mobility. By considering that the transport system is not sustainable, we measure mobility costs thanks to three indicators which represent the sustainability of household mobility: the annual costs of household urban mobility, the annual effort rate devoted by households to their transportation expenditures and the annual CO2 emissions. The link between urban form and mobility is not straightforward. Actually, it is a complex reciprocal link to be defined. The literature shows that three dimensions of local environment finally influence household mobility: density, diversity and accessibility. The method consists on confronting the factors alleged to explain the indicators of the sustainability of household mobility and on determining which part is explained by urban form. On the enlarged perimeter of the household travel survey of Lyon (2006), our approach based on household mobility costs enables, moreover, an approach to financial inequalities and introducing the notion of household vulnerability facing their transportation costs. In order to determine the share of mobility costs explained by urban form, we build some explanatory models, at the household level, by integrating urban form and socio-economic household variables. Especially the analysis focuses on the influence of secondary urban poles on the household vulnerability and mobility costs. Some explanatory models by household types show also that the effects of urban form are differentiated according to household categories. It is also interesting to measure the savings generated by marginal changes of urban form. To do that, we build some econometric models in a more aggregated level which allows computing elasticity coefficients. Thus, we can estimate, in economic terms, the expected savings that are triggered by urban form changes.
102

Analýza schém podpory obnovitelných zdrojů energií v EU: Může být EKOlogické i EKOnomické? / Analysis of the renewable energy support schemes in the EU: Can be an ECOlogical also an ECOnomical?

Andoková, Senta January 2015 (has links)
The study compares FIT (Feed-in tariff) and RPS (Renewable Portfolio Standard) as the two most commonly used support schemes for renewable energy sources (RES) in the EU. It examines a relationship of an Environmental Kuznets Curve (EKC) and by a practical experiment for public lighting in Prague the study proposes an ecological functioning of electricity grids in the EU with CO2 emissions reduction effect. The main contribution lies in the recency and originality of the econometric analysis and practical experiment. FIT and RPS analysis demonstrates that both schemes affect demand for electricity and increase its price. The econometric model was tested for 28 EU countries for 1990-2013. The results say that the EU is currently located on the downslope of the inverted U-shaped EKC with a turning point, after which the dependence begins to grow. Nevertheless, for the most of observations the turning point is too far to be a source of concern. Practical experiment has shown that installation of energy saving devices for electricity grids in the EU can bring satisfactory results in reducing CO2 emissions independently of state aid. More efficient use of existing energy sources, however, should rather serve as a complement to conventional support, phasing out with the development of RES technologies....
103

Design of Ultra High Performance Fibre Reinforced Concrete Bridges : A Comparative Study to Conventional Concrete Bridges

Eriksson, Viktor January 2019 (has links)
The use of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) in the construction industry started in the 1990s and has since then been used for bridges all over the world. The mechanical properties and the dense matrix result in lower material usage and superior durability compared to conventional concrete, but the implementation of UHPFRC in the Swedish industry has been delayed. The most evident explanation, based on interview with industry representatives, as to why UHPFRC is not commonly used in Sweden are due to the lack of standards and knowledge. UHPFRC also has a high cement content and the cement industry contributes with high carbon dioxide (CO2) emissions to the total CO2 emissions in the world. This MSc Thesis looks into if a UHPFRC bridge is a feasible alternative to a conventional reinforced concrete structure bridge from design and material usage perspectives, regarding reduction of CO2 emissions. The project’s overall goal is to increase the knowledge in Sweden about the material, regarding the production, mechanical properties and behaviour of UHPFRC, and the design, regarding the difference in design between UHPFRC and conventional concrete bridges. To examine the material, a UHPFRC mixture with short straight steel fibres was developed. Specimens were tested to see how the different fibre contents affect the mechanical properties and which fibre content that is most favourable. Three different fibre contents were tested: 1.5%, 2.0% and 2.5% of the total volume of the mixture. The tested and evaluated mechanical properties were workability, flexural strength, tensile strength, fracture energy, compressive strength and modulus of elasticity. This study does not contain tests of durability of UHPFRC, however trough the literature review it was investigated to what extent the fibres affect the durability. It was concluded that an increase in fibre content results in improved mechanical properties, except for workability and in some cases when using a fibre content of 2.5%. The increase in the mechanical properties is due to the increased cracking resistance and the bond strength between the fibres and the matrix. The decrease in the mechanical properties, e.g. characteristic tensile strength and compressive strength of cylinders, for 2.5% in fibre content can be due to uneven fibre distribution and higher amount of air in the specimens which result in less strength. It was concluded that 2.0% in fibre content is most favourable. It was possible to conclude that the degradation of the fibres takes a long time, however not to what extent the fibres will affect the durability. To evaluate if UHPFRC is a viable economical and environmental alternative to regular concrete bridges, three cases of bridge design are considered. Two cases with UHPFRC (different thickness) and one case with conventional concrete. Up to 2017 only technical guidelines and recommendations for design with UHPFRC existed, but in 2017 the first approved standards in the world were published. The French national standards cover material (NF P18-470, 2016) and design (NF P18-710, 2016) and were used for the design process. The material usage regarding the amount of reinforced UHPFRC/concrete and steel reinforcement as well as the amount of CO2 emissions from the production of cement and steel (fibre and steel reinforcement) used for the bridges in the mid-span and at the support were investigated. The design process was also evaluated. It was concluded that the UHPFRC bridge with an optimized thickness was 47% lighter than the conventional concrete bridge, but the amount of CO2 emissions was still higher (e.g. 23% from the support). To be able to determine if a UHPFRC bridge is a feasible alternative to a conventional concrete bridge, with regards to the reduction of CO2 emissions, the CO2 emissions have to be observed in a wider perspective than only from the production of cement and steel, e.g. fewer transports and longer lifetime. / Användningen av ultrahögpresterande fiberbetong (UHPFRC) i anläggningsindustrin började på 1990-talet och har sedan dess använts till broar i hela världen. De mekaniska egenskaperna och den täta UHPFRC matrisen resulterar i lägre materialanvändning och bättre beständighet i jämförelse med konventionell betong, men användningen av UHPFRC har inte slagit igenom i den svenska industrin. De största förklaringarna till varför UHPFRC sällan används i Sverige är för att det inte har funnits kunskap och standarder. UHPFRC har också en hög cementhalt och cementindustrin bidrar med höga koldioxid (CO2) utsläpp till de totala CO2 utsläppen i världen. Den här masteruppsatsen skrevs för att undersöka om en UHPFRC bro är ett möjligt alternativ till en konventionell betongbro ur dimensionering- och materialanvändningssynpunkt med avseende på reduktion av CO2 utsläpp. Projektets övergripande mål är att öka kunskapen om materialet, med avseende på tillverkningen, de mekaniska egenskaperna och beteendet av UHPFRC, och dimensionering, med avseende på skillnaden i dimensionering mellan UHPFRC broar och konventionella betongbroar. I materialdelen utvecklades ett UHPFRC recept med korta raka stålfibrer. Provkroppar testades för att se hur olika fiberinnehåll påverkade de mekaniska egenskaperna och vilket fiberinnehåll som var mest gynnsamt. Tre olika fiberinnehåll testades: 1.5%, 2.0% och 2.5% av total volym av blandningen. De mekaniska egenskaperna som testades och utvärderades var bearbetbarheten, böjhållfasthet, draghållfasthet, fraktur energi, tryckhållfasthet och elasticitetsmodul. Beständigheten av UHPFRC testades aldrig men i vilken omfattning fibrerna påverkar beständigheten undersöktes i den litteraturstudie som skrevs inför testerna och tillverkningen av UHPFRC. Det konstaterades att en ökning i fiberinnehåll resulterade i en ökning av de mekaniska egenskaperna, förutom för bearbetbarheten och i vissa fall när ett fiberinnehåll av 2.5% användes. Ökningen av de mekaniska egenskaperna berodde på det ökande sprickmotståndet och bindningsstyrka mellan fibrerna och matrisen. Minskningen av de mekaniska egenskaperna, till exempel den karakteristiska drag- och tryckhållfastheten, när ett fiberinnehåll på 2.5% i cylindrar användes kan bero på ojämn fiberfördelning och större mängd luft i provkropparna vilket resulterar i lägre hållfasthet. Det konstaterades att ett fiberinnehåll på 2.0% var det mest gynnsamma. Det kunde inte konstateras i vilken omfattning fibrerna påverkar beständigheten men det kunde konstateras att nedbrytningen av fibrerna tar lång tid. I dimensioneringsdelen utformades tre slakarmerade balkbroöverbyggnader, i två fall var överbyggnaden med UHPFRC (olika tjocklekar) och i ett fall var den med konventionell betong. Fram till 2017 fanns det bara tekniska riktlinjer och rekommendationer för UHPFRC men 2017 publicerades de första godkända standarderna i världen. De franska nationella standarderna täcker material (NF P18-470, 2016) och dimensionering (NF P18-710, 2016) och användes vid dimensioneringen. Materialanvändningen med avseende på mängd armerad UHPFRC/betong och slakarmering och mängd CO2 utsläpp från produktionen av cement och stål (fibrer och slakarmering) som användes till broarna i mittenspannet och vid stöden undersöktes. Även dimensioneringsprocessen utvärderades. Det konstaterades att UHPFRC bron med optimerad tjocklek var 47% lättare än betongbron men mängden CO2 utsläpp var fortfarande högre (till exempel 23% högre från stödet). Det konstaterades att om det ska vara möjligt att fastställa att en UHPFRC bro är ett möjligt alternativ till en konventionell betongbro, med avseende på reduktion av CO2 utsläpp, måste CO2 utsläppen ses från ett bredare perspektiv än från bara produktion av cement och stål, till exempel mindre transporter och längre livslängd.
104

Desenvolvimento e aplicação de um modelo para o Pollution Routing Problem. / Developing and implementing a model for a Pollution Routing Problem.

Paschoal, Anderson Oliveira de Ornelas 27 April 2015 (has links)
O transporte rodoviário é uma das atividades econômicas do homem que mais contribuem para a emissão de Gases de Efeito Estufa (GEE) na atmosfera. Sabe-se que a emissão de CO2 está diretamente vinculada ao consumo de combustível. Por isso, é possível encontrar uma série de trabalhos que objetivam diminuir as emissões por meio da redução do consumo de combustível dos veículos. A otimização de rotas é uma importante ferramenta para essa redução e, consequentemente, possibilita minimizar as emissões dos veículos. Esta pesquisa tem como objetivo aplicar em uma empresa líder na distribuição de revistas no país o PRP, que é um modelo de minimização do consumo de combustível/emissão de GEE por meio de ajustes das variáveis como velocidade média, quantidade de carga transportada, distância percorrida e inclinações das vias. Como a maioria das metodologias de estimativa de combustível existentes na literatura não considera a inclinação das vias nos seus cálculos, neste trabalho foi necessário desenvolver uma metodologia para incluí-la no modelo. Testes foram efetuados com variações nas janelas de tempo, e o modelo mostrou-se sensível a cada uma das variáveis analisadas, gerando economias em 100% das rotas estudadas. / Road transport is one of the biggest contributors of Greenhouse Gases emissions of all humans economic activities. It is known that CO2 emissions are directly related to fuel consumption, so that is why it is possible to find a series of studies that aims to reduce emissions by reducing vehicles fuel consumption. Route optimization is an important tool for reducing fuel consumption and hence emissions. This research aims to implement the PRP model in a leading company in the country, which is a model that minimizes fuel consumption/GHG emissions through adjustments of variables such as average speed, pay load, distance traveled and slopes of the road. Most existing fuel estimation methodologies found in the literature does not consider the slope of the roads in their calculations. So in this research it was necessary to develop a methodology to include it in the model. Tests were performed with variations in the time windows and the model was sensitive to each of the variables analyzed, generating savings on 100% of the studied routes.
105

Incentivos e tributos: promovendo veículos menos poluentes e a economia de combustível / Incentives and taxes: promoting cleaner vehicles and fuel economy

Kurokawa, Régis Toshimitsu 08 August 2018 (has links)
O setor de transporte automotivo é um dos principais responsáveis pelas emissões de gases nocivos à saúde ou causadores do efeito estufa. Existem inúmeras propostas econômicas para a redução destas emissões, que se dividem basicamente entre regulamentação de emissões e impostos sobre combustível ou veículos. Apresentaremos neste trabalho um esquema de feebate, uma alternativa baseada num mercado de carbono em que um carro que tem emissões de poluentes abaixo de certo nível ganha um subsídio para sua compra, enquanto que outro que apresenta emissões acima paga um imposto. Este esquema é projetado para que no fim, contabilizados o imposto pago e o subsídio oferecido, faça com que o governo não tenha receita, nem despesas com este. Para mostrar sua eficácia, faremos simulações com base em estimações do mercado de automóveis brasileiro do período de 2008 a 2012 usando um modelo de escolhas discretas através de um logit multinomial aninhado, e faremos análises de bem estar. / The automotive transport sector is one of the main responsible for emissions of harmful gases and greenhouse gases. There are numerous economics proposals for reducing these emissions, which are basically divided between emission regulations and taxes on fuel or vehicles. We will present in this work a feebate scheme, an alternative based on a carbon market in which a car that has emissions of pollutants below a certain level gains a subsidy for its purchase, while another that presents emissions above a level pays a tax. This scheme is designed so that at the end, counting the tax paid and the subsidy offered, make the government have no revenue, nor expenses with it. To show its effectiveness, we will make simulations of this scheme based on estimates of the Brazilian auto market from 2008 to 2012 using a discrete choice model with a nested multinomial logit, and we will analise social welfare changes.
106

Comparação termodinâmica e ambiental (emissões de CO2) das rotas de produção e utilização de combustíveis veiculares derivados de petróleo e gás natural, biocombustíveis, hidrogênio e eletricidade (veículos elétricos). / Thermodynamics and environmental comparison (CO2 emissions) of production and end use routes of vehicle fuels, derived from petroleum, natural gas, biofuels, hydrogen and electricity (electric vehicles).

Flórez-Orrego, Daniel Alexander 21 February 2014 (has links)
O setor de transporte é um exemplo de atividade econômica que depende fundamentalmente das cadeias produtivas do petróleo, gás natural e biocombustíveis para sua operação, além de ser um dos principais consumidores da energia primária do país. Portanto, qualquer melhoria nos processos de produção e uso final dos combustíveis veiculares, repercute favoravelmente tanto na utilização dos recursos energéticos e o desempenho do setor, quanto no impacto ambiental e na economia nacional. Nesse sentido, faz-se necessário o desenvolvimento de uma metodologia que permita avaliar as diferentes rotas de produção e uso final, para determinar as principais fontes de degradação da energia e quantificar o impacto ambiental por meio de uma ferramenta apropriada. Uma valiosa ferramenta é a análise exergética ampliada, a qual provê uma oportunidade de quantificar os requerimentos exergéticos totais e não renováveis e as eficiências globais e, desse modo, perseguir e priorizar o uso daquelas fontes de energia mais favoráveis e amigáveis com o meio ambiente. A exergoeconomia, que visa à distribuição racional dos custos exergéticos entre os diversos produtos de uma mesma planta, usa a quantidade de exergia de cada produto como base para a distribuição da exergia despendida no respectivo processo. Desta forma, neste trabalho se apresenta uma análise comparativa sobre as rotas de produção e uso final dos combustíveis derivados do petróleo e o gás natural (inclusive o hidrogênio produzido da reforma a vapor), etanol, biodiesel, além da análise da geração e distribuição da eletricidade na matriz elétrica brasileira. Propõe-se o uso dos custos exergéticos unitários renováveis e não renováveis e as emissões de CO2 como indicadores para avaliar a intensidade exergética renovável e não renovável, o impacto ambiental e o desempenho termodinâmico no uso final. Este procedimento permite hierarquizar os diferentes processos de conversão de energia na produção e uso final de combustíveis veiculares, a fim de determinar as melhores opções para o setor de transporte. / Transportation sector is an example of economic activity that fundamentally depends on the supply chains of oil, natural gas and biofuels for its operation, as well as being a major consumer of primary energy in the country. Therefore, any improvement that could be achieved in the vehicle fuels production and end use processes, favorably affects both the use of energy resources and industry performance, as well as the environmental impact and the national economy. Accordingly, it is necessary to develop a methodology based on a suitable tool to evaluate the different routes of fuel production and end use, so that the main sources of energy degradation and the environmental impact can be determined and quantified. A valuable tool that serves that purpose is the extended exergy analysis, which provides an opportunity to quantify the total and non-renewable exergy requirements and overall efficiencies, and thereby pursue and prioritize the use of the most environmentally friendly sources of energy. Exergoeconomy, which attempts to rationally distribute the exergy cost among the several products of a single plant, uses the amount of exergy of each product as the basis for the distribution of exergy expended in the respective process. Thus, this work presents a comparative analysis of the production routes and end use of vehicles fuels derived from petroleum and natural gas (including hydrogen produced from methane steam reforming), ethanol, biodiesel, besides of the analysis of generation and distribution of electricity in the Brazilian electricity mix. Moreover, the renewable and non-renewable unit exergy costs and CO2 emissions are proposed as indicators, able to assess the renewable and non-renewable specific exergy consumption, the environmental impact and the thermodynamic performance of transportation sector. This procedure allows to hierarchize the exergy conversion processes in the production and end use of transportation fuels, in order to determine the best options for the transportation sector.
107

Vulnerabilidade da matéria orgânica do solo ao aumento de temperatura / Vulnerability of soil organic matter to temperature increase

Lisboa, Carolina Cardoso 29 August 2008 (has links)
Durante o processo de decomposição da matéria orgânica do solo (MOS) ocorre a formação de gases do efeito estufa (GEE) que são liberados para a atmosfera contribuindo para o aquecimento global. Acredita-se que este aquecimento global possa retroagir na taxa de decomposição da MOS potencializando a liberação de carbono (C) do solo. A MOS está distribuída em frações com sensibilidades diferentes à temperatura. Pesquisas anteriores sugerem que a fração de C mais velha e mais recalcitrante é menos sensível à temperatura (C-recalcitrante). Além disso, alguns mecanismos de proteção física, química e bioquímica podem agir para reduzir a sensibilidade da MOS ao aumento de temperatura. Possíveis modificações na estrutura da comunidade microbiológica, provocadas pelo aumento de temperatura, podem interferir no processo de decomposição da MOS através de alterações nos seus mecanismos de proteção. A mudança do uso da terra é um dos principais responsáveis pela emissão dos GEE no Brasil. A substituição da vegetação original (floresta) por pastagem promove uma modificação no sinal 13C do C do solo, dando um indício sobre a origem do C liberado na forma de CO2. Com o objetivo de avaliar a vulnerabilidade da MOS ao aumento de temperatura foram realizadas incubações de solos, oriundos de floresta e pastagens, em duas temperaturas 25 e 35 ºC. Avaliou-se a sensibilidade dos compartimentos C-lábil e C-recalcitrante da MOS à temperatura e, como as possíveis alterações nos mecanismos de proteção da MOS podem contribuir com a liberação de CO2 à atmosfera. / Soil organic matter (SOM) decomposition emits greenhouse gases to the atmosphere and this may contribute to global warming. Global warming can promote a positive feedback on SOM decomposition rate and it can increase soil C losses. The SOM has different pools with inherent temperature sensitivity. Some researches suggest that resistant soil C is less sensitive to temperature increase. Moreover, there are some physical, chemical and biochemical mechanisms that protect SOM against decomposition. The global warming may change the soil microbial structure and it can modify SOM decomposition. In Brazil, the greenhouse gas emissions are basically driven by the land use change. The substitution of native vegetation (forest) to pasture changes soil C signature - 13C and this fact enable us to study the source of soil C emissions. The objective of this study was to evaluate the SOM vulnerability to temperature increased. Forest and pastures soil samples were incubated under 25 and 35 ºC. The labile-C versus resistant-C temperature sensitivity was evaluated and the SOM protection mechanisms were studied to understand how they can protect SOM against decomposition.
108

Exploitation et réhabilitation de bâtiments tertiaires : une démarche énergétique d'amélioration environnementale

Valderrama Ulloa, Claudia 13 November 2013 (has links)
Le secteur du bâtiment est l’un secteur des plus énergivore, sa consommation énergétique importante découle d’une part de la dégradation des matériaux propre à leur vieillissement et d’autre part, au manque d’un cadre réglementaire énergétique plus strict accompagnant la conception. Enfin cette consommation énergétique est due à la présence des usagers. Ceci est d’autant plus vrai pour le secteur tertiaire au travers leurs activités, leurs comportements et leur degré d’appartenance que les usagers donnent à ces types de bâtiments. En effet, même si tout le monde les utilise, personne ne se sent responsable de leur maintenance. Le travail présenté ici met en avant la relation entre la consommation énergétique dans les campus universitaires et le comportement des usagers. Les résultats sont analysés dans un contexte climatique comparable (paramètre clé les Degrés Jours Unifiés - DJU), avec indicateurs d’évaluation partageables (ce qui ont été judicieusement choisis à partir d’une comparaison entre différents systèmes d’évaluation) et traduit dans une méthodologie d’évaluation (basée sur les méthodes multicritères). Celle-ci tient compte de la multiplicité d’usages, d’usagers et d’attentes énergétiques, environnementales et de confort présents dans ce type de secteur tertiaire. L’objectif principal de cette étude a été d’élaborer une démarche d’amélioration environnementale et énergétique pour l’exploitation des bâtiments tertiaires, pour aller vers la réhabilitation thermique et énergétique, en considérant d’une part, la satisfaction des usagers et d’autre part les performances énergétiques et environnementales améliorées des bâtiments analysés. Ce mémoire de thèse est construit autour la logique suivante : une mise en situation des problématiques énergétiques internationales et nationales (France et du Chili). Un focus sur l’énergie dans le secteur tertiaire, permet de s’imprégner des différents dispositifs mis en place pour atteindre l’objectif de réduction de la consommation d’énergie et des émissions de CO2. Une grille de comparaison qui va nous permettre de réaliser les analyses de consommations énergétiques à différentes périodes de l’année avec un seul paramètre climatologique le DJU, est mise en avant. Ensuite les différents campus et sites universitaires sur lesquels nous appuyons la réflexion sont présentés. Dans ceux-ci, nous analysons à différentes échelles spatio-temporelles et avec différents types d’analyses qualitatives et quantitatives, les variables discriminantes qui seront essentielles pour parvenir à une amélioration énergétique au fil du temps. Par la suite, une ligne de base de critères et indicateurs qui vont nous permettre d’évaluer avec la même échelle d’évaluation, la performance énergétique et environnementale des bâtiments dans leur état actuel est crée. Pour, ensuite, les comparer dans un état optimisé lorsque les améliorations énergétiques ont été mises en place. Enfin nous proposons une méthodologie d’évaluation et d’amélioration environnementale pour l’exploitation des bâtiments tertiaires qui va mettre en relation de façon originale les besoins énergétiques, environnementaux, économiques et de confort des gestionnaires et des usagers universitaires. Une modélisation thermique de solutions de réhabilitation et un modèle économique, assez simple, sont proposés pour illustrer l’application de la méthodologie. / The buildings sector is one of the largest energy consuming sectors, its high energy consumption stems to construction materials degradation on the one hand and to the lack of a stricter regulatory context in design step on the other hand. Finally, this energy consumption is due to the presence of users. This is especially true for the service sector through its activities, its behavior and the sense of belonging of users to this type of buildings. Even if everyone uses them, nobody feels responsible for their maintenance.The work presented here highlights the relationship between energy consumption in university campuses and user’s behavior. The results are analyzed in a comparable climatic context (the key parameter Unified Degree Days - UDD) with sharable assessment indicators (which have been carefully selected from a comparison between different assessment systems). Then, the results are translated into an evaluation methodology (based on multicriterio analysis). The methodology takes into account the multiplicity of uses, users and energy resources, environment and comfort requirements expected in this service sector.This study aims to develop an environmental and energy improvement approach for the operation of tertiary buildings, to move towards a thermal and energy rehabilitation, considering on the one hand, user satisfaction and on the other hand the energy and environmental improved performance of the studied buildings.This manuscript of thesis is built around the following logic: an overview of national and international energy issues (France and Chile). A specific reference to energy in the tertiary sector emphasizes the different mechanisms put in place to achieve the reduction target of energy consumption and CO2 emissions. A comparison grid is built to analyze energy consumptions at different times of the year with a single climate parameter: the DDU (Unified Degree Days). Then, the different campuses and universities supported by the reflection are presented. In these study cases, we analyzed at different spatio-temporal scales and with different types of qualitative and quantitative analysis, the discrimination of critical variables to achieve energy improvements over time. Subsequently, a baseline of criteria and indicators is developed to evaluate the energy and environmental performance of buildings in their current state with the same rating scale. Then energy improvements are implemented to compare them in an optimized state. Finally, we propose an evaluation methodology and environmental improvements for the operation of tertiary buildings which will bring together in an original way the energy, environmental, economic and comfort managers and users universities needs. Thermal modeling solutions and economic rehabilitation rather simple model are provided to illustrate the application of the methodology. / El sector de la construcción es uno de los sectores que más energía consume, este consumo se debe en parte a la degradación de sus materiales, propia al paso del tiempo, a la falta de un marco legal energético más estricto que regule su diseño-concepción y por otra a la presencia de sus usuarios. Este fenómeno se vuelve más recurrente en el sector terciario debido a sus actividades, sus comportamientos y el grado de pertenencia que los usuarios le dan a este tipo de edificios. De hecho, si es cierto que todo el mundo los puede utilizar, no todos se sienten responsables de su cuidado.El trabajo que aquí se ha desarrollado presenta la relación entre el consumo energético de los campus universitarios y el comportamiento de sus usuarios. Los resultados se han analizado bajo un contexto climático comparable (parámetro clave los Grados Días Unificados - GDU), indicadores de evaluación adaptables (que han sido cuidadosamente seleccionados a partir de una comparación entre distintos sistemas de evaluación - certificaciones) y que se han traducido a través de una metodología de evaluación (basada en métodos de multicriterio). Esta metodología considera la multiplicidad de usos, de usuarios y de requerimientos energéticos, medioambientales y de confort presentes en este tipo de sector terciario.El objetivo principal de este estudio ha sido desarrollar una metodología de mejora energética y medioambiental para la operación de edificios terciarios, que permitirá además de considerar una rehabilitación térmica y energética, teniendo en cuenta, por una parte, la satisfacción de los usuarios y por otra el desempeño energético y medioambiental mejorado de los edificios analizados.La memoria de la tesis ha sido construida bajo la siguiente lógica: la presentación de las problemáticas energéticas internacionales y nacionales (de Francia y de Chile). Una visión de la energía en el sector terciario, permite ahondar sobre los diferentes mecanismos establecidos para lograr el objetivo de reducir el consumo energético y las emisiones de CO2. Un sistema de comparación nos permite analizar el consumo energético en diferentes periodos del año, a través de un único parámetro climático, el GDU. A continuación se presentan los diferentes campus y sitios universitarios en los que nos apoyamos para el análisis. En ellos, analizamos a diferentes escalas espacio-temporales y con diferentes tipos de análisis cualitativos y cuantitativos, las variables discriminantes que serán fundamentales para lograr la mejora de la eficiencia energética a través del tiempo. Posteriormente, construimos una línea de base de criterios e indicadores que nos permitirá evaluar a través de una misma escala de evaluación, el desempeño energético y medioambiental de los edificios en su estado actual, para luego compararlos en un estado óptimo cuando diferentes mejoras energéticas se han implementado. Por último, proponemos una metodología de evaluación y de mejoras energéticas para la operación de edificios terciarios, dicha metodología relaciona de manera original las necesidades energéticas, medioambientales, económicas y de confort de gestores y de usuarios universitarios. Finalmente, proponemos para ilustrar la aplicación de la metodología, un modelo térmico de soluciones de rehabilitación y un modelo económico simplificados.
109

Essays on Consumers' Willingness-to-Pay for Energy Efficiency: Empirical Evidence for the German Automobile Market

Pleshcheva, Vlada 21 January 2019 (has links)
Diese Dissertation quantifiziert die Zahlungsbereitschaft (ZB) der Konsumenten für die Verbesserung des Kraftstoffverbrauchs von Personenkraftwagen (PKW) und untersucht die Faktoren, die den unterschiedlichen Verbraucherbewertungen dieser Verbesserungen zugrunde liegen. Die Arbeit besteht aus drei eigenständigen Aufsätze, deren wissenschaftlichen Beiträge sowohl im inhaltlichen als auch im methodischen Bereich liegen. Auf der methodischen Seite nutzt die Arbeit verschiedene Datentypen und statistische Verfahren, um die ZB-Werte zu ermitteln. Inhaltlich werden in der Arbeit die Auswirkungen verschiedener Faktoren untersucht, von denen einige in der Literatur noch nicht oder nur teilweise im Zusammenhang mit der ZB für Kraftstoffeffizienz erforscht wurden. Der erste Aufsatz untersucht die Auswirkungen von Kraftstoffpreisen auf den Marktwert der Kraftstoffeffizienz. Dabei wird zwischen Änderungen im Budget für die Nutzung eines Autos mit niedrigerem Kraftstoffverbrauch und Änderungen im Budget für dessen Kauf unterschieden. Anhand offenbarter Präferenzdaten in Form aggregierter Marktdaten wird analysiert, wie sich die Unterschiede in den Fahrzeugattributen im Preis widerspiegeln und wie Änderungen der Kraftstoffpreise die ZB für den Kraftstoffeffizienz beeinflussen. Die Untersuchung im zweiten Aufsatz basiert ebenfalls auf offenbarten Präferenzdaten, aber auf individueller Ebene. Diese Art von Daten ermöglicht es, die individuelle Bewertung der Kraftstoffeffizienz zu ermitteln und die Heterogenität der Verbraucher bezüglich ihrer Zahlungsbereitschaft mit beobachteten verbraucher- und transaktionsspezifischen Merkmalen in Beziehung zu setzen. Der dritte Aufsatz quantifiziert die Unterschiede in den Präferenzen der Verbraucher für identische Verbesserungen des Kraftstoffverbrauchs sowie der CO2-Emissionen mit Hilfe von wahlbasierten Conjoint-Experimenten. Die Rolle der individuellen Merkmale in der ZB von Verbrauchern wird zusätzlich untersucht. / The present thesis quantifies the consumers' willingness-to-pay (WTP) for improvements in fuel efficiency of passenger cars with gasoline and diesel engines at the German automobile market and explores factors related to consumers' differences in the valuation of these improvements. The thesis consists of three self-contained essays with the contributions in both the conceptual and the methodological domain. Methodologically, the thesis exploits various data types and statistical techniques to elicit the WTP values, whereas conceptually, it considers the effects of various determinants, some of which have not yet or only partially been studied in the literature on the consumer valuation of fuel efficiency. The first essay investigates the effects of fuel prices on the market value of fuel economy while distinguishing between changes in the budget for driving a car with better fuel economy and changes in capital investments in better car quality. Revealed preference data, in the form of aggregate market data on vehicle prices and attributes for diesel and gasoline cars, are used to analyze how the differences in attributes of cars are reflected in their prices and to explore co-movements of the vehicle price sensitivity to fuel economy with changes in fuel prices. The investigation in the second essay is also based on revealed preference data, but from the observed car purchase transactions at the individual level. This type of data allows to recover the individual valuation of fuel efficiency and to relate the recovered heterogeneity in consumers' WTP for a reduction in fuel costs to the observed consumer- and purchase-related characteristics. The third essay quantifies the differences in consumers' preferences for identical improvements in FC and CO2 emissions using stated preference data. The role of individual characteristics in the consumers' WTP for these environmentally important attributes is additionally studied.
110

Quantificação dos impactos econômicos e ambientais decorrentes do estado de conservação das rodovias brasileiras / Quantifying of the economic and environmental impacts deriving from Brazilian\'s highways state of conservation

Bartholomeu, Daniela Bacchi 21 November 2006 (has links)
Devido à importância do modal rodoviário para a economia brasileira no que diz respeito à sua participação na matriz de transporte de cargas, à elevada participação no consumo de combustíveis fósseis (óleo diesel) e nas emissões de CO2, esta Tese avaliou se rodovias em melhores estados de conservação implicam benefícios econômicos e ambientais. Os benefícios econômicos disseram respeito à avaliação dos seguintes parâmetros: consumo de combustível, tempo de viagem e gasto com manutenção do veículo. Já os benefícios ambientais referiram-se às reduções das externalidades negativas resultantes da diminuição nas emissões de CO2. Foram realizadas coletas de dados primários relacionados ao desempenho observado em caminhões em rodovias com diferentes condições de infra-estrutura. Nesse sentido, foram conduzidos dois conjuntos de experimentos, envolvendo rotas e tipos diferentes de caminhões, aos quais foram acoplados computadores de bordo para auxiliar na coleta dos dados. O primeiro conjunto de experimentos envolveu quatro rotas, as quais foram percorridas por um caminhão Volvo FH12, fabricado em 2004. Num total de 48 viagens, foram observados o consumo de combustível, e o perfil das velocidades em cada trajeto. Os resultados indicaram a existência de benefícios econômicos e ambientais para as rotas em melhor estado de conservação. No segundo conjunto de experimentos, foram selecionadas duas rotas em diferentes estados de conservação., nas quais dois caminhões de fabricantes distintos (Scania R124-420 e MB 1944S) realizaram um total de 40 viagens. Nesses experimentos, também foram comparados os resultados observados em cada tipo de veículo, tendo sido possível concluir que o tipo de tecnologia apenas impactou no consumo de combustível. Finalmente, os dados dos dois conjuntos de experimentos foram agregados, a fim de estimar valores mais próximos à realidade, já que na prática, há diversos tipos de modelos e fabricantes de caminhão. Ainda assim, os resultados obtidos confirmam a existência de benefícios econômicos e ambientais resultantes de viagens em rotas com melhor infra-estrutura: há um aumento na eficiência energética em rotas melhores, implicando menor consumo de combustível e menores níveis de emissão de CO2. A análise estatística dos resultados sugeriu que, em geral, os dados relacionados ao consumo de combustível eram significativos ao nível de significância de 5%, rejeitando a hipótese nula de que o consumo médio das rotas em piores estados de conservação é estatisticamente igual ao consumo médio observado em rotas com melhores condições. Portanto, tratou-se de indicação em favor da hipótese alternativa, de que o consumo médio observado em rotas piores é maior do que aquele em rotas melhores. / Due to importance of the road transportation for the Brazilian economy related to its participation in the matrix of load transport, to its high participation in the fossil fuels consumption (diesel) and in the CO2 emissions, this study evaluated if highways in better state of conservation imply in economic and environmental benefits. The economic benefits were related to the evaluation of the following parameters: fuel consumption, duration of the trip and expenses on vehicle maintenance. The environmental benefits related to the CO2 emissions reduction. It was collected primary data related to the performance observed in trucks on highways with different infrastructure conditions. In this aspect, it was carried out two sets of experiments, involving different routes and types of trucks, to which cutting edge computers were connect to assist the collection of the data. The first set of experiments involved four routes covered by a Volvo FH12 truck, manufactured in 2004. In a total of 48 trips, the fuel consumption, and the velocity profile in each passage were observed. The results showed the existence of economic and environmental benefits in the routes with better conservation. In the second set of experiments, two routes in different states of conservation were selected, in which two trucks from distinct manufacturers (Scania R124-420 and MB 1944S) performed a total of 40 trips. In these experiments, the results observed in each type of vehicle were compared, which allowed to conclude that the type of technology only impacted on the fuel consumption. Finally, the data of the two sets of experiments were aggregated, in order to approximate the values to the reality, once in reality there are several types of truck models and manufacturers. Still, the results confirm the existence of economic and environmental benefits deriving from trips in routes with better infrastructure: there is a gain in energy efficiency, resulting in less fuel consumption and lower levels of CO2 emissions. The statistical analysis of the results suggested that, in general, the data related to the fuel consumption were significant to the level of significance of 5%, rejecting the null hypothesis that the average fuel consumption in the routes in worse states of conservation is statistically equal to that observed in routes in better condition. Therefore, it is indicated that the alternative hypothesis is significant that the observed average consumption in worse routes is bigger than that observed in better routes.

Page generated in 0.0627 seconds