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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.
271

Urban form and sustainability : Comparison between low-rise “garden cities” and  high-rise “compact cities” of suburban areas

Vlassopoulou, Efstathia January 2019 (has links)
Urbanization and climate change are two of the most important issues of our days. Many attempts have been made to define the most sustainable way to organise cities in order to cope with the increased population, while simultaneously being climate friendly, socially acceptable and economically viable. This master thesis focuses on the comparison of the sustainability performance of two particular theoretically planned urban forms, located in the suburban area of Stockholm – a “compact city”-like neighborhood and a “garden-city”-like neighbourhood. It was decided that the focus would be on the carbon footprint of the representative residences of each urban form, with the help of Life Cycle Assessment (LCA); and that overall sustainability criteria for neighbourhoods would after wards be assessed, having a certification system forsustainable neighbourhoods (CityLab for districts, in particular) as a framework for a – mostly theoreticalassessment. After the exploring of the differences in the sustainability performance(environmental and social) of the two assessed urban forms, a discussion is made concerning the relationship between urban form and sustainability and conditions under which the most sustainable urban form could be achieved. The results of the analysis highlight that the concept “one size fits all” cannot conform to urban planning decisions, since cities should be able to adjust to the needs of each generation.
272

MQL versus Dry Machining - a Comparative Analysis in a Turning Process using LCA / MQL eller torrskärning -­ en jämförande studie för en svarvningsprocess med hjälp av LCA

Shams, Shadi January 2018 (has links)
During the last decades the challenge of sustainability has become more urgent and environmental impacts of different processes in manufacturing industry have received more attention. Life cycle assessment (LCA) has become an important and useful tool to evaluate the environmental impact of products and processes. In this study the environmental impact of two cooling techniques in a turning process has been evaluated using LCA. Turning is used for shaping metal parts by removing material. The compared cooling techniques in this study are dry cutting and Minimum Quantity Lubrication (MQL). The inputs and output in each technique are considered in form of material flows and energy consumption as well as waste flows. The Ecoinvent database has been used in order to quantify, evaluate and compare the environmental impacts of the two cooling techniques. Environmental impact categories considered in this study are Carbon footprint (CO2 kg equivalent), Cumulative Energy Demand (CED), Total eco-cost in Euro and ReCiPe. ReCiPe is a method used to evaluate multiple environmental impact categories and it covers impact categories related to human health, ecotoxicity and material depletion. Calculations and analysis of the results show that MQL has significantly lower environmental impact compared to dry cutting whereas energy consumption is the main contributor in the considered environmental impact categories. / Under de senaste åren har hållbar utveckling blivit mer relevant och miljöpåverkan av olika tillverkningsprocesser i industrin har således fått mer uppmärksamhet. Livscykelanalys (LCA) har blivit ett viktigt och användbart verktyg för att analysera och utvärdera miljöpåverkan av produkter och processer. I det här examensarbetet har miljöpåverkan av två olika kylmetoder vid svarvning utvärderats med hjälp av livscykelanalys (LCA). Svarvning används för att forma metalldelar. De jämförda kylmetoderna är torrskärning (dry cutting) utan kylvätska och minimalsmörjning (Minimum Quantity Lubrication - MQL) där en liten mängd smörjmedel används. Tillfört material, energiförbrukning och avfall vid varje kylmetod har betraktats. Ecoinvent-databasen har använts för att kvantifiera, utvärdera och jämföra miljöpåverkan av de två kylmetoderna. Miljöpåverkanskategorierna som behandlas i denna studie är koldioxidavtryck (CO2 kg ekvivalent), kumulativt energibehov (CED), totala miljökostnader i Euro och ReCiPe. ReCiPe är en metod som används för att utvärdera flera olika miljöpåverkanskategorier inkluderande människors hälsa, miljögifter och förbrukning av naturresurser. Beräkningarna och analysresultaten visar att MQL har betydligt lägre miljöpåverkan än torrskärning och att energiförbrukningen är den mest avgörande faktorn.
273

Comparative Life Cycle Assessment of Jeans : A case study performed at Nudie Jeans

Åslund Hedman, Emma January 2018 (has links)
Within the jeans production industry, large quantities of cotton, water and chemicals are consumed on a daily basis resulting in environmental issues decentralized around the world. An increased awareness about these environmental issues amongst companies, organizations and the consumers have initiated for environmental aspects to be considered within the jeans production processes. One such initiative is the introducing of CSR management into the business operations and strategy. In order to see how well the environmental targets and performance succeed with capturing the existing environmental issues more information about the specific products is required. This thesis was conducted to evaluate and compare the environmental impacts of three jeans manufactured by Nudie Jeans from a life cycle perspective and to evaluate the environmental focus at Nudie Jeans. Accordingly the main purpose has been to evaluate the environmental performance of jeans at Nudie Jeans. The main purpose have been divided into the two sub- targets: To find out which of the three styles of jeans: Lean Dean Lost Legend, Tilted Tor Dry Royal Embo and Grim Tim Conjunctions, manufactured at Nudie Jeans, that has the best environmental performance and why. To find out how well the prioritized environmental sustainability targets and measures represent their potential environmental impact. The evaluation is based on nine main environmental aspects, assessed to be relevant and of interest for the given case. The LCA has been performed according to the methodology and guidance presented in the ISO 14040-standard to ensure a methodological structure with high credibility. The studied products are the three styles of jeans: Lean Dean Lost Legend, Tilted Tor Dry Royal Embo and Grim Tim Conjunctions. The main difference between the products can be found in what companies and in which countries the life cycle phases: cotton cultivation, fabric manufacturing and jeans production are conducted. The results of the study show that Grim Tim Conjunctions and Tilted Tor Dry Royal Embo have the best environmental performance and the worst environmental performance can be found in Lean Dean Lost Legend. The results are mainly caused by two main process contributors, the energy sources used for electricity and heating and the substances used in the dyeing, laundry and finishing processes. A sensitivity analysis on the results gathered from the LCA shows that Nudie Jeans is to the largest extent focusing on the right environmental aspects. The focus on organic cotton cultivation and the promoting of repairs are highly reflecting the environmental importance within the subject, however, the measures and targets regarding energy usage could be improved to better represent its environmental importance.
274

Life Cycle Management as framework for successful Life Cycle Assessment implementation in the commercial vehicle industry

Burul, Dora January 2018 (has links)
The transport industry is in the middle of a conceptual shift driven by delivering the targets set by the Paris Agreement. Proactive heavy-duty vehicle companies seek to further gather knowledge in a structured way on environmental impacts of its products and services. The method to be implemented is Life Cycle Assessment (LCA). For implementation of LCA certain organisational and operational factors pre-requirements need to be addressed. The study takes key factors of Life Cycle Management (LCM) as a framework for assessing the readiness of Scania CV AB to implement LCA. Said key factors of LCM are analysed through company-based case study observations and literature review. The results indicate the company is in the process of introducing majority of the key factors of LCM. The case study tested the possibilities of the company for LCA, and attempted second phase of LCA, Life Cycle Inventory (LCI). The greatest challenge to LCA is low availability and format of data for LCA. However, the case study deeply tested the data limits and offers good insight in actions to be taken.
275

Integration of LCA into the building design process

Jerome, Adeline January 2019 (has links)
The required estimation of performances of a building cannot be limited to its energy efficiency anymore. Environmental issues are rising concerns into national policies. However, information about construction products is still segmented into several distinct databases: the construction company gathered data for its design process into private pricing databases while environmental declarations from manufacturers are available in a public database. The interconnection of the different information about the same product is difficult because of the difference of data formatting and representation. The objective of this project was to provide first tools to facilitate this interconnection between the design process of the company and environmental data, considering incoming requirements from the new thermal regulation of 2020. This led to the creation of a SQL environmental database, based on environmental declarations, more adapted for statistical analysis than a document-based database. Specific data management functions were also developed to homogenise unit representation and to spot product performances for the purpose of multi-criteria analysis of products Finally, an estimation of the distinctiveness of products through a selection of key words was tested. The comparison of lists of words provided good performances for their classification into a limited number of lots. But it is not sufficient to identify items that can be related to the same construction product. So further works is needed into the creation of a semantic metric model of construction vocabulary.
276

Methodology for the Life Cycle Assessment of a Car-sharing Service

Guyon, Olivier January 2017 (has links)
Nowadays, circular economy is becoming more relevant in society. In the context of the automotive industry, we no longer simply work on emissions emitted during the vehicle use phase but rather on the environmental impacts induced during all phases of the vehicle's life cycle (manufacturing, logistics, use, maintenance and end of life). For this purpose, many automakers, including the Group PSA, use life cycle assessment (LCA) to determine these environmental impacts. Also, the economy of sharing is gradually established and follows innovative uses of the car. New mobility systems emerge and compete with the classical system of sales of vehicles. These new uses of the automobile mainly take the form of car-sharing. In the future, it will become essential to evaluate these services from an environmental point of view.Some studies of the use of car-sharing already demonstrate important consequences such as reductions in the number of vehicles and in the number of kilometers traveled but also an increase in the use of other means of transport. However, to my knowledge, there is no LCA-based method to quantify the environmental benefit of the use of a car-sharing service in relation to the use of vehicles for exclusive use by the owner but also which would eco-design these services and the vehicles intended for these services.As part of this six-month project, a LCA approach was implemented to a PSA B2C (business-to-consumers) car-sharing service called “Emov” with a fleet of 500 Citroën C-Zero electric vehicles. The goal was to compare the use of Emov in Madrid, Spain with the urban use of a private Internal Combustion Engine (ICE) vehicle and a battery electric vehicle for one user characterized by its frequency, its average time and its average distance of use over a defined period. Thanks to a modeling of the service on the LCA software Gabi and by controlling over the input parameters related to the Emov service and the parameters related to the user's use of the service (variable parameters), it was therefore possible to show the influence of these parameters on the final results. Furthermore, it was possible to show also in which scenario it was more environmentally beneficial to use the service rather than a private vehicle. For the study, six impact indicators were chosen: the potentials for global warming, photochemical oxidation, air acidification, water eutrophication, resource depletion and primary energy demand.Using Emov’s big data to inform the service parameters and then varying the service user's usage parameters, it was possible to conclude that whatever the user's urban mobility needs, it is more beneficial to use the service than a private ICE vehicle for five of the six impact indicators. Only the acidification potential indicator (SO2 equivalent) is worse when using the service, which can be explained by the manufacture of the batteries of the Emov vehicles.
277

Sustainability Assessment Of Wind Energy For Buildings

Noori, Mehdi 01 January 2013 (has links)
Due to increasing concerns for global climate change, onshore and offshore wind energy technologies have stimulated a tremendous interest worldwide, and are considered as a viable solution to mitigate the environmental impacts related to electricity generation. Although wind energy technologies have been considered as one of the cleanest energy sources, they have a wide range of direct and indirect environmental impacts when the whole supply chain is considered. This study aims to quantify the direct and indirect environmental impacts of onshore and offshore wind power technologies by tracing all of the economy-wide supply chain requirements. To accomplish this goal, we developed a comprehensive hybrid life cycle assessment (LCA) model in which process-based LCA model is combined with the economic input-output (EIO) analysis. The analysis results show that on average, concrete and steel and their supply chains are responsible for 37% and 24% of carbon footprint, consequently. On average, offshore wind turbines produce 48% less greenhouse gas emissions per kWh produced electricity than onshore wind turbines. For the onshore wind turbines, concrete, aggregates, and crushed stone approximately consume 95% of total water in this construction phase. On the other hand, concrete, lead, copper, and aggregate are responsible for around 90% of total water for the offshore wind turbines. It is also found that the more capacity the wind turbine has, the less environmental impact the wind turbine generates per kWh electricity. Moreover, based on the economic and environmental impacts of studied wind turbines and also three more nonrenewable energy sources, this study develops a decision making framework to understand the best energy source mix for a building in the state of Florida. This framework accounts for the uncertainty in the input material by deploying a Monte Carlo iii simulation approach. The results of decision making framework show that natural gas is a better option among nonrenewable sources. On the other hand, V90-3.0 MW offshore wind turbine is the best source of energy among renewable energy sources for a building. The findings of this research are critical for policy makers to understand the direct and indirect environmental impacts of different onshore and offshore wind energy systems. Also this study furnishes the decision maker with a range of possible energy mixes based on different economic and environmental weights.
278

Life Cycle Assessment of Absolicon solar thermal collector field for district heating in Härnösand / Livscykelanalys av Absolicon solfångarfält för fjärrvärme i Härnösand

Ariyakhajorn, Ohm January 2023 (has links)
Global energy consumption has been increasing continuously every year. Many energy sources are utilized. Conventional fossil fuels are not sustainable, and their environmental impacts are more apparent than ever before. For heating purposes, most of the heat still comes from combustion of both non-renewable and renewable energy sources. According to IEA (2019), only 10% of heat supply in industrial sectors and buildings comes from renewable sources. Hence, 40% of the carbon emission in the energy sector comes from heat. Therefore, shifting from non-renewable to renewable energy sources is essential in reducing the environmental impact from heat production. Sweden has a long tradition of solar thermal in district heating for cities. Therefore, this study tried to look at the application of solar thermal energy for heat production to supply the District Heating (DH) system and compare its environmental performance to other types of energy sources. The system that was examined in this study is the solar thermal collector field from Absolicon in Härnösand. A Life Cycle Assessment (LCA) was conducted to evaluate the life cycle environmental impacts of this solar collector field. The assessment was done by collecting primary data provided by Absolicon and its suppliers and secondary data from the literatures. The results showed that Absolicon solar thermal collector field generated less overall environmental impacts than conventional energy sources in heat production. Moreover, the result for carbon footprint of the solar collector is 4.4 kg CO2/MWh, which is at least 3-4 times less lifetime emissions when compared to other solar energy technologies. / Den globala energiförbrukningen har ökat kontinuerligt varje år. Många energikällor används. Konventionella fossila bränslen är inte hållbara och deras miljöpåverkan är mer påtaglig än någonsin tidigare. För uppvärmningsändamål kommer det mesta av värmen fortfarande från förbränning av både icke-förnybara och förnybara energikällor. Enligt IEA (2019) kommer endast 10 % av värmeförsörjningen i industrisektorer och byggnader från förnybara källor. Därför kommer 40 % av koldioxidutsläppen i energisektorn från värme. Därför är en övergång från icke-förnybara till förnybara energikällor väsentligt för att minska miljöpåverkan från värmeproduktion. Sverige har en lång tradition av solvärme inom fjärrvärme för städer. Därför försökte denna studie titta på tillämpningen av solvärmeenergi för värmeproduktion för att försörja fjärrvärmesystemet (DH) och jämföra dess miljöprestanda med andra typer av energikällor. Systemet som undersöktes i denna studie är solfångarfältet från Absolicon i Härnösand. En livscykelanalys (LCA) genomfördes för att utvärdera livscykelns miljöpåverkan av detta solfångarfält. Bedömningen gjordes genom att samla in primärdata från Absolicon och dess leverantörer och sekundärdata från litteraturen. Resultaten visade att Absolicon solfångarfält genererade mindre total miljöpåverkan än konventionella energikällor vid värmeproduktion. Dessutom är resultatet för solfångarens koldioxidavtryck 4,4E kg CO2/MWhvilket är minst 3-4 gånger mindre livstidsutsläpp jämfört med andra solenergitekniker.
279

Site Characterization, Sustainability Evaluation and Life Cycle Emissions Assessment of Underground Coal Gasification

Hyder, Zeshan 10 October 2012 (has links)
Underground Coal Gasification (UCG), although not a new concept, is now attracting considerable global attention as a viable process to provide a "clean" and economic fuel from coal. Climate change legislation and the declining position of coal reserves (i.e., deeper and thinner seams) in many parts of the world are promoting and fueling the UCG renaissance. This research presents an analysis of operational parameters of UCG technology to determine their significance and to evaluate the effective range of values for proper control of the process. The study indicates that cavity pressures, gas and water flow rates, development of linkage between wells, and continuous monitoring are the most important operating parameters. A protocol for the selection of suitable sites for UCG projects is presented in this study. The site selection criteria are developed based on successes and failures of previous experiments and pilot studies. The criteria take into account the site characteristics, coal quality parameters, hydrology of the area, availability of infrastructure and regulatory and environmental restrictions on sites. These criteria highlight the merits and demerits of the selected parameters, their importance in site selection and their economic and environmental potentials. Based on the site selection criteria, a GIS model is developed to assist in selecting suitable sites for gasification in any given area of interest. This GIS model can be used as a decision support tool as well since it helps in establishing the tradeoff levels between factors, ranking and scaling of factors, and, most importantly, evaluating inherent risks associated with each decision set. The potential of UCG to conform to different frameworks defined to assess the capability and potential of any project that merits the label, "sustainable," has been evaluated. It has been established that UCG can integrate economic activity with ecosystem integrity, respect for the rights of future generations to the use of resources and the attainment of sustainable and equitable social and economic benefits. The important aspects of UCG that need to be considered for its sustainable development are highlighted. In addition, the environmental benefits of UCG have been evaluated in terms of its potential for reduction in greenhouse gas (GHG) emissions. The findings indicate that UCG significantly reduces GHG emissions compared to other competitive coal exploiting technologies. A model to compute the life cycle greenhouse emissions of UCG has been developed, and it reveals that UCG has distinctive advantages in terms of GHG emissions over other technologies and competes favorably with the latest power generation technologies. In addition to GHG emissions, the environmental impacts of these technologies based on various impact assessment indicators are assessed to determine the position of UCG in the technology mix. It is clear from the analysis that UCG has prominent environmental advantages and has the potential to develop and utilize coal resources in an environmentally friendly and economically sound manner. / Ph. D.
280

Towards Sustainable Construction: Life Cycle Assessment of Railway Bridges

Du, Guangli January 2012 (has links)
Since last few decades, the increased pressure from the environmental issues of natural resource depletion, global warming and air pollution have posed a great challenge worldwide. Among all the industrial fields, bridge infrastructures and their belonged construction sector contribute to a wide range of energy and raw materials consumptions, which is responsible for the most significant pollutions. However, current bridges are mainly designed by the criterion of economic, technique, and safety standards, while their correlated environmental burdens have unfortunately rarely been considered. The life cycle assessment (LCA) method has been verified as a systematic tool, which enables the fully assessment and complete comparison for the environmental impact among different bridge options through a life cycle manner. The study presented in this thesis is focused on railway bridges, as the LCA implementation is under great expectations to set a new design criterion, to optimize the structural design towards the environmental sustainability, and to assist the decision-making among design proposals. This thesis consists of two parts: an extended summary and three appended papers. Part one gives an overview introduction that serves as a supplementary description for this research work. It outlines the background theory, current development status, the LCA implementation into the railway bridges, as well as the developed excel-based LCA tool. Part two, includes three appended papers which provides a more detailed theoretical review of the current literatures and knowledge associated with bridge LCA, by highlighting the great challenging issues. A systematic flowchart is presented both in Paper I and Paper II for how to model and assess the bridge life cycle, together by coping with the structural components and associated emissions. This flowchart is further illustrated on a case study of the Banafjäl Bridge in Sweden, which has been extensively analyzed by two LCA methods: CML 2001 method and streamlined quantitative approach. The obtained results can be contributed as an analytical reference for other similar bridges. Based on the theoretical review and analytical results from case studies, it has been found that the environmental profile of a bridge is dominated by the selected structural type, which affects the life cycle scenarios holistically and thus further influences the environmental performance. However, the environmental profile of the structure is though very case specific; one cannot draw a general conclusion for a certain type of bridge without performing the LCA study. The case study has found that the impact of material manufacture phase is mostly identified significant among the whole life cycle. The availability of the inventory data and project information are appeared as the major problem in the bridge LCA study. Moreover, lack of standardized guideline, criteria and input information is another key issue. A criterion is needed to illustrate what are the qualified limits of a bridge to fulfill the environmental requirements. Therefore, the development of LCA for railway bridges still needs further collaborative efforts from government, industry and research institutes. / QC 20120227

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