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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.
1

Construction of prefabricated concrete buildings : A comparative attributional LCA / Konstruktion av prefabricerade betongbyggnader : En jämförande LCA

Wingårdh, Ludvig January 2021 (has links)
This master thesis investigated the influence of prefabrication rate of buildings on the embodied environmental impacts. Through a comparative attributional LCA four different Swedish buildings were investigated to explore the influence of PR on the environmental impacts in the categories Cumulative Energy Demand, Global Warming Potential, Water Consumption, Fossil Resource Scarcity, and Mineral Resource Scarcity. The reference buildings had prefabricated rates of 14, 26, 38 and 91%. The results indicate that a higher prefabricated rate (PR) can lead to a lower impact in these categories to some extent; mainly due to a lower amount of total concrete material per square meter, dependent on the construction method used. The most influential materials in the comparison where cement and steel. An initial improvement of several impacts was seen when the PR of concrete buildings increased from 14% to 38%, with one reason being increased material efficiency of concrete. When further increasing PR, it is not certain that impacts necessarily continue to improve, as no clear difference was shown between the buildings with PR of 91% and 38%. This seems to point towards that any clear relationship between PR and the chosen impact categories breaks down or flattens out for higher prefabricated rates, and that the most beneficial solution often could be a semi-prefabricated construction method. This is concurrent with previous results in the current body of literature on LCA of construction and prefabricated rates. Instead, for additional reduction of environmental impacts after this point, other factors such as material choice and could become increasingly important. Additionally, the question of which impact category to prioritize arises. / Denna masteruppsats undersöker betydelsen av andelen prefabricerad betong i byggnader och dess påverkan på den inbyggda miljöpåverkan. En jämförande bokförings-LCA gjordes av fyra svenska referensbyggnader för att undersöka prefabrikationsgradens inverkan i fem kategorier av miljöpåverkan: kumulativ energiförbrukning, global uppvärmning, vattenförbrukning, och förbrukning av minerala och fossila naturresurser. Referensbyggnaderna hade prefabricerade andelar av 14, 26, 38 och 91%. Resultaten indikerar att en högre grad av prefabricering kan leda till en lägre påverkan i de undersökta kategorierna i viss mån, inte minst på grund av en lägre total förbrukning av betong per kvadratmeter BTA, beroende på vilken konstruktionsmetod som används. De mest betydelsefulla råmaterialen fanns vara cement och stål. En initial förbättring i flertalet kategorier syntes när prefabrikationsgraden ökade från 14 till 38%, mycket tack vare den lägre betongförbrukningen. När prefabrikationsgraden steg ytterligare till 91% syntes ingen tydlig förbättring, och det kan inte anses klarlagt att en högre prefabrikationsgrad nödvändigtvis har lägre miljöpåverkan. Detta indikerar att den mest fördelaktiga lösningen ofta kan vara en semi-prefabricerad lösning, vilket överensstämmer med resultaten i tidigare studier på området. För ytterligare reducering av miljöpåverkan efter en viss grad av prefabricering framstår andra faktorer såsom materialval som allt viktigare.
2

Avaliação consequencial do ciclo de vida: discussão e aplicação comparativa com a abordagem atribucional / Consequential life cycle assessment: discussion and comparative application with the attributional approach

Michelle Tereza Scachetti 28 April 2016 (has links)
A Avaliação do Ciclo de Vida é uma das principais técnicas de avaliação ambiental de bens e serviços e pode ser classificada em duas abordagens: atribucional e consequencial. A atribucional, caracterizada pelo uso de dados médios de ICV e de alocação de coprodutos, tem como objetivo a avaliação dos impactos ambientais de um produto do berço ao túmulo, em um sistema estático. A ACV consequencial consiste na avaliação das consequências ambientais em um sistema dinâmico, orientado por mudanças. Esta abordagem vem sendo intensamente discutida na literatura internacional, porém, no Brasil ainda se trata de um tema pouco explorado. O presente trabalho visa aprofundar a discussão entre as duas abordagens da ACV. Para isso, utilizaram-se os seguintes procedimentos metodológicos: revisão da literatura e aplicação das abordagens ao biocombustível etanol hidratado de cana-de-açúcar. Os resultados apontam que a ACV atribucional apresentou maiores cargas ambientais em todas as categorias de impacto, com principalmente nas categorias de Ecotoxicidade Aquática, Ecotoxicidade Terrestre e Depleção Abiótica. Isto se deve à subtração das cargas ambientais referentes aos produtos evitados, considerados na análise devido à expansão do sistema realizada na abordagem consequencial com a finalidade de evitar a alocação que, por sua vez, foi utilizada na abordagem atribucional. Notou-se que, em teoria, a principal diferença entre as abordagens da ACV consiste em seus distintos alinhamentos quanto à aplicação pretendida, sendo a atribucional voltada ao conhecimento dos impactos ambientais do ciclo de vida de um produto e identificação de pontos críticos no sistema, e a abordagem consequencial voltada à identificação das consequências ambientais geradas por uma mudança no sistema de produto investigado. Na prática, entretanto, foram encontradas algumas limitações que comprometeram a operacionalização do estudo consequencial, distanciando-a do seu propósito teórico. Dentre estas limitações merecem destaque: o grande número de simplificações intrínsecas ao método aplicado e a falta de transparência quanto à base de dados de background utilizada. Notou-se que a operacionalização da ACV consequencial é bastante complexa, pois despende muito tempo e recursos, principalmente na coleta e validação de informações de mercado. Portanto, reforça-se a necessidade de esforços no sentido do desenvolvimento de métodos menos subjetivos e mais sistemáticos para a abordagem consequencial além de diretrizes mais esclarecedoras explicitando as diferenças quanto ao conteúdo, contextos e formas de aplicação das abordagens atribucional e consequencial da ACV e indicando em quais situações elas podem ser complementares. / Life Cycle Assessment is one of the most used tool to asses environmental impact of goods and services. It can be classified into two approaches: attributional and consequential.Attributional LCA, characterized by the use of average data ICV and coproducts allocation is aimed at assessing the environmental impacts of a product from the cradle to the grave, in a static system. The consequential LCA is the evaluation of the environmental consequences in a dynamic system driven by changes. Both approaches have been intensively discussed in the literature in recent years, but in Brazil it is still a little discussed and explored topic. Thus, this study aims to deepen the discussion between the two LCA approaches. For this, the following methodological procedures are used: literature review and application of the approaches on hydrated bioethanol from sugarcane. The results show that the attributional LCA has higher environmental burdens in all impact categories, with greater difference with consequential in the categories of aquatic and terrestrial ecotoxicity and abiotic depletion. This is due to the subtraction of environmental charges related to avoided products, considered at the time of system expansion in consequential approach, which did not occur in attributional (where co- products were treated by means of allocation). The main differences between the approaches reflect their different alignments on the intended application, the attributional approach is mostly focused on the knowledge of the environmental impacts of the life cycle of a product and identification of improvement points to the system, while the consequential approach aims to verify potential environmental consequences generated by the change in product system investigated. In practice, however, it was observed that the consequential LCA results should be interpreted with great caution due to the fact that the application has brought a large number of limitations, such as: great number of simplifications of the method applied, consideration of standard assumptions when the lack of information for the collection of data and lack of transparency as to the basis of background data used. Moreover, its implementation is still quite complex, requiring much time and resources to collect data and market information. Therefore, we reinforce what has already been established through the literature review: efforts are needed towards the development of less subjective methods and more systematic for consequential approach as well as more enlightening guidelines explaining the differences in the content, context and application forms of attributional and consequential LCA approaches.
3

Avaliação consequencial do ciclo de vida: discussão e aplicação comparativa com a abordagem atribucional / Consequential life cycle assessment: discussion and comparative application with the attributional approach

Scachetti, Michelle Tereza 28 April 2016 (has links)
A Avaliação do Ciclo de Vida é uma das principais técnicas de avaliação ambiental de bens e serviços e pode ser classificada em duas abordagens: atribucional e consequencial. A atribucional, caracterizada pelo uso de dados médios de ICV e de alocação de coprodutos, tem como objetivo a avaliação dos impactos ambientais de um produto do berço ao túmulo, em um sistema estático. A ACV consequencial consiste na avaliação das consequências ambientais em um sistema dinâmico, orientado por mudanças. Esta abordagem vem sendo intensamente discutida na literatura internacional, porém, no Brasil ainda se trata de um tema pouco explorado. O presente trabalho visa aprofundar a discussão entre as duas abordagens da ACV. Para isso, utilizaram-se os seguintes procedimentos metodológicos: revisão da literatura e aplicação das abordagens ao biocombustível etanol hidratado de cana-de-açúcar. Os resultados apontam que a ACV atribucional apresentou maiores cargas ambientais em todas as categorias de impacto, com principalmente nas categorias de Ecotoxicidade Aquática, Ecotoxicidade Terrestre e Depleção Abiótica. Isto se deve à subtração das cargas ambientais referentes aos produtos evitados, considerados na análise devido à expansão do sistema realizada na abordagem consequencial com a finalidade de evitar a alocação que, por sua vez, foi utilizada na abordagem atribucional. Notou-se que, em teoria, a principal diferença entre as abordagens da ACV consiste em seus distintos alinhamentos quanto à aplicação pretendida, sendo a atribucional voltada ao conhecimento dos impactos ambientais do ciclo de vida de um produto e identificação de pontos críticos no sistema, e a abordagem consequencial voltada à identificação das consequências ambientais geradas por uma mudança no sistema de produto investigado. Na prática, entretanto, foram encontradas algumas limitações que comprometeram a operacionalização do estudo consequencial, distanciando-a do seu propósito teórico. Dentre estas limitações merecem destaque: o grande número de simplificações intrínsecas ao método aplicado e a falta de transparência quanto à base de dados de background utilizada. Notou-se que a operacionalização da ACV consequencial é bastante complexa, pois despende muito tempo e recursos, principalmente na coleta e validação de informações de mercado. Portanto, reforça-se a necessidade de esforços no sentido do desenvolvimento de métodos menos subjetivos e mais sistemáticos para a abordagem consequencial além de diretrizes mais esclarecedoras explicitando as diferenças quanto ao conteúdo, contextos e formas de aplicação das abordagens atribucional e consequencial da ACV e indicando em quais situações elas podem ser complementares. / Life Cycle Assessment is one of the most used tool to asses environmental impact of goods and services. It can be classified into two approaches: attributional and consequential.Attributional LCA, characterized by the use of average data ICV and coproducts allocation is aimed at assessing the environmental impacts of a product from the cradle to the grave, in a static system. The consequential LCA is the evaluation of the environmental consequences in a dynamic system driven by changes. Both approaches have been intensively discussed in the literature in recent years, but in Brazil it is still a little discussed and explored topic. Thus, this study aims to deepen the discussion between the two LCA approaches. For this, the following methodological procedures are used: literature review and application of the approaches on hydrated bioethanol from sugarcane. The results show that the attributional LCA has higher environmental burdens in all impact categories, with greater difference with consequential in the categories of aquatic and terrestrial ecotoxicity and abiotic depletion. This is due to the subtraction of environmental charges related to avoided products, considered at the time of system expansion in consequential approach, which did not occur in attributional (where co- products were treated by means of allocation). The main differences between the approaches reflect their different alignments on the intended application, the attributional approach is mostly focused on the knowledge of the environmental impacts of the life cycle of a product and identification of improvement points to the system, while the consequential approach aims to verify potential environmental consequences generated by the change in product system investigated. In practice, however, it was observed that the consequential LCA results should be interpreted with great caution due to the fact that the application has brought a large number of limitations, such as: great number of simplifications of the method applied, consideration of standard assumptions when the lack of information for the collection of data and lack of transparency as to the basis of background data used. Moreover, its implementation is still quite complex, requiring much time and resources to collect data and market information. Therefore, we reinforce what has already been established through the literature review: efforts are needed towards the development of less subjective methods and more systematic for consequential approach as well as more enlightening guidelines explaining the differences in the content, context and application forms of attributional and consequential LCA approaches.
4

Transition of non-production facilities towards carbon-neutrality A Case Study- Volvo CE’s Customer Center

Aliahmad, Abdulhamid, Mohan, Aisiri January 2020 (has links)
Research on historical developments that lead to the establishment of global organizations for climate change has shown that the phenomenon of surface temperature is not a new topic of focus. Increased policy restrictions, brand image, fear of resource scarcity, growing market trends towards sustainability and consumer awareness are among the several external factors that have influenced the growing research in corporate transition towards carbon neutrality. The main aim of this study is to understand through data accounting of major material and energy carrier changes, how a non-production facility could transition to become a carbon-neutral facility. Therefore, an exploratory case study has been performed and conducted at Volvo CE Customer center in Eskilstuna, Sweden, with two objectives: i) to identify and quantify the customer center current footprint by mapping the main contributors to greenhouse gases emissions, and ii) to recommend specific & general measures that can mitigate the carbon footprint of the facility. Three research questions related to the facility’s current carbon footprint, measures implemented so far, and the best applied assessment method, have guided us throughout the study. The methodology has been framed to give a theoretical underpinning for understanding the project from a holistic perspective. The split of the methodology has been constructed in line with the theoretical framework that gave the foundation to the needed theories to be taken into account i.e. GHG protocol, which is the tool that has been adopted by the study to attain the desired aim, including the three scopes under the protocol which were also defined accordingly. ‘Scope 1’ has been taken into account and is a representation of direct emissions, ‘Scope 2 represents the indirect emissions, and ‘Scope 3’ (according to the GHG protocol) takes into account the rest of the indirect emissions arranged into 15 categories, from which applicable to our study were 4 categories (1, 3, 4 and 6). The results showed that during the base year (2019) the highest user within Scope 1 was diesel, followed by HVO, and under Scope 2, The results from Scope 1 and 2, together with the results of Scope 3 category, were analyzed using the attributional LCA approach recommended by the GHG protocol to calculate their contribution to the customer centers’ total carbon footprint. It was found that Scope 1 stands for 128.52 t CO₂-eq while Scope 2 stands only for 1.16 t CO₂-eq and finally Scope 3 stands for most of the emissions with 3719 t CO₂-eq. It has been found that in 2019, the customer center has saved 101.05 tonnes of GHG by implementing measures, such as switching from using Diesel to HVO and switching from the mixed electricity to the renewable ones, according to the attributional perspective presented in the GHG protocol. However, different results were found when these values were discussed and analyzed from the consequential perspective, since this perspective analyses the effects of the implemented measures on the global emission level. This concluded that implementation of conservation and efficiency measures must take priority before switching to higher priced renewables. Thus, the resulting carbon neutrality will be consequentially safer. The recommendations stated in this study also follows the same principle “Conserve before investing”. Suggestions and recommendations outlined in the study for future implementation approach carbon neutrality as a strategy and not a burden, helping the customer neutral achieve the goal in an Environment, Economic and Socially sustainable manner.
5

Analyse de cycle de vie de la production bovine : exploration de pratiques et de changements de système pour réduire les impacts environnementaux / Life cycle assessment of cattle production : exploring practices and system changes to reduce environmental impacts

Nguyen, Thi Tuyet Hanh 21 December 2012 (has links)
Cette thèse porte sur l’étude des impacts environnementaux de systèmes de production de bovins. Le premier objectif était d’analyser et de comparer les impacts environnementaux de systèmes de production de viande et de lait par analyse de cycle de vie (ACV) attributionnelle. Les effets de pratiques d’atténuation de ces impacts ont été évalués pour les systèmes de production de viande. Le second objectif était un développement méthodologique afin d’explorer les conséquences possibles d’une préférence accrue pour un lait produit à base d’herbe, par ACV conséquentielle. Dans un système de production de viande par le troupeau allaitant, le méthane entérique a été le principal contributeur à l’impact changement climatique, et la production de l’herbe a été la principale contributrice aux autres impacts (demande énergétique cumulée, eutrophisation, acidification, occupation du sol). L’atelier naisseur (vaches allaitantes et leurs veaux, génisses) a contribué de manière majeure aux impacts du système allaitant dans son ensemble. La pratique d’atténuation la plus efficace pour le système a été la diminution de l’âge au vêlage de 3 à 2 ans. L’utilisation de lipides riches en acides gras oméga-3 dans le régime a très peu affecté les impacts du système. L’application simultanée de plusieurs pratiques d’atténuation compatibles entre elles réduit sensiblement les impacts. L’application de pratiques telles que la réduction du gaspillage d’herbe, l’engraissement des génisses non utilisées pour le renouvellement et la diminution de l’âge au vêlage réduisent l’occupation du sol. Un usage alternatif des terres libérées tel que la plantation de forêt pour séquestrer du carbone dans la biomasse semble prometteur. L’étude de systèmes de production de lait a été centrée sur les comparaisons de systèmes à base d’herbe ou d’ensilage de maïs, d’une race spécialisée (Holstein) ou mixte (Normande) et sur l’effet du niveau de production laitière par ACV attributionnelle. Quelle que soit la méthode d’attribution des impacts aux co-produits, les impacts par kg de lait ont été plus faibles pour les systèmes à base d’ensilage de maïs et pour les Holstein, sauf pour l’eutrophisation. L’accroissement de la production de lait par vache grâce à une consommation d’énergie accrue et au vêlage à 2 ans a permis de réduire les impacts du lait et de son co-produit viande. Les conséquences de la conversion d’une exploitation laitière utilisant beaucoup de maïs ensilage vers une exploitation utilisant de l’herbe comme unique source de fourrage pour répondre à une demande de lait produit à base d’herbe en France ont été évaluées par ACV conséquentielle. Cette conversion entraîne des changements notables de l’utilisation des sols en dehors de l’exploitation, et donc un fort accroissement des impacts du système dans son ensemble et du lait produit. / This thesis addresses the environmental impacts of cattle production systems. The first objective of this thesis was to analyse and compare the environmental impacts of suckler-beef and dairy production systems using attributional life cycle assessment (ALCA). Subsequently, the effects of mitigation practices for suckler-beef production systems were assessed. The second objective addressed methodology development by exploring possible consequences due to an increase in preference for grass-based milk using consequential LCA (CLCA).For a suckler-beef production system, enteric methane fermentation was the main contributor to the climate change impact, and grassland production contributed most to other impacts (cumulative energy demand, eutrophication, acidification and land occupation). The suckler cow-calf herd substantially contributed to the impacts of the suckler-beef system. The most effective mitigation practice for the suckler-beef production system was decreasing calving age from 3 to 2 years. The use of lipids rich in omega-3 fatty acids in ruminant diets did not substantially affect the impacts of the suckler-beef production system. Simultaneous application of several compatible practices can substantially mitigate the impacts of the suckler-beef production system. The application of certain practices (e.g. reducing ungrazed grass losses, fattening heifers not used for replacement and reducing calving age) reduced land occupation. Alternative uses for the “released land”, e.g. the introduction of forest to sequester C into biomass, seems promising. For dairy production systems, the assessment focused on a grass-based vs. maize-silage-based system, dual-purpose breed (Normande) vs. specialised breed (Holstein) and the effect of increasing milk yield per cow, using the ALCA approach. Independent of co-product handling methods, the impacts per kg of milk were lower with the maize-silage-based system and with Holstein cows (except for eutrophication). Increasing milk yield per cow by increasing feed energy intake and applying more intensive management (first calving at 2 years) decreased the impacts of milk and its beef co-product. The consequences of converting a maize-silage-based to a grass-based dairy farm in France to meet the increased domestic preference for grass-based milk were assessed using the CLCA approach. This farm conversion caused land-use change outside the dairy farm and thus substantially increased the impacts of the whole production system and the milk it produced.

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