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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.
31

Strategier för implementering av cirkulär ekonomi i byggbranschen

Bergdoff, Philip January 2022 (has links)
The construction and real estate industry is one of Sweden's largest consumers of energy andraw materials. According to figures from Boverket, the building industry was responsible for21% of Sweden's total greenhouse gas emissions in 2019. If Sweden is to fulfil its commitmentsunder the Paris Agreement and at the same time achieve the climate goals for the 2030 Agenda,resourceefficient measures are required immediately. The transition to circular economy can bea vital step in this necessary change. In circular economy, it is crucial to eliminate waste andpollutants which can be achieved by increasing efficiency and maintaining products andmaterials in a circular cycle. The aim of this study is to examine which strategies can be applied to implementing circulareconomy in the construction industry and what opportunities and obstacles they entail. I havealso investigated whether life-cycle assessment can be an effective tool for this implementation.To answer these questions, interviews have been carried through with researchers and businessrepresentatives who have extensive knowledge of sustainable construction and who arecommitted to finding solutions to combat climate change in the construction industry. Anextensive literature study has also been performed. The results indicate that there are several opportunities and sought-after measures with thecircular economy concept, of which the most significant one is its potential to increase resourceefficiency and thereby generate climate benefits. Strategies for the implementation of CEinclude methods such as circular procurement, design for deconstruction, material passports,upcycling and reversible building design. New smart business models can also generate newrevenues and create more employment opportunities. Challenges highlighted in the study are above all lack of financial incentives. For instance, inmost cases, it is at present more profitable to buy virgin than secondary materials. The lack ofspace for intermediate storage of materials to be reused is also a challenge. There is often a lackof knowledge with suppliers and customers. In addition, there are several legal issues regardingthe division of responsibilities and finally the need of more efficient policy instruments.
32

Simulation of steam gasification in a fluidized bed reactor with energy self-sufficient condition

Suwatthikul, A., Limprachaya, S., Kittisupakorn, P., Mujtaba, Iqbal M. 06 March 2017 (has links)
Yes / The biomass gasification process is widely accepted as a popular technology to produce fuel for the application in gas turbines and Organic Rankine Cycle (ORC). Chemical reactions of this process can be separated into three reaction zones: pyrolysis, combustion, and reduction. In this study, sensitivity analysis with respect to three input parameters (gasification temperature, equivalence ratio, and steam-to-biomass ratio) has been carried out to achieve energy self-sufficient conditions in a steam gasification process under the criteria that the carbon conversion efficiency must be more than 70%, and carbon dioxide gas is lower than 20%. Simulation models of the steam gasification process have been carried out by ASPEN Plus and validated with both experimental data and simulation results from Nikoo & Mahinpey (2008). Gasification temperature of 911 °C, equivalence ratio of 0.18, and a steam-to-biomass ratio of 1.78, are considered as an optimal operation point to achieve energy self-sufficient condition. This operating point gives the maximum of carbon conversion efficiency at 91.03%, and carbon dioxide gas at 15.18 volumetric percentages. In this study, life cycle assessment (LCA) is included to compare the environmental performance of conventional and energy self-sufficient gasification for steam biomass gasification. / Financing of this research was supported by the Thailand Research Fund (TRF) under Grant Number PHD57I0054 and the Institutional Research Grant by the Thailand Research Fund (TRF) under Grant Number IRG 5780014 and Chulalongkorn University, Contact No. RES_57_411_21_076.
33

Factors Impeding the Advancement of Straw Bale As a Feasible and Sustainable Construction Building Material in North America

McIntosh, Sean P. 20 September 2011 (has links)
No description available.
34

Life Cycle Assessment of Lightweight Electric Motorbikes : Case Study - RIDECAKE / Livscykelbedömning av lätta elektriska motorcyklar : Fallstudie - Ridecake

Englert, Savitri Visvanathan January 2023 (has links)
The electric vehicle segments of companies have broadened, and their sales have increased in the past decade. The electric motorcycle sector is growing fast, with improved technology on electric powertrains, increased ranges, charging speeds, and infrastructure. Parallel to the increased sales, the electric battery sector is advancing rapidly, thereby lowering the environmental impacts of these vehicles. The competitive adventure sports sector also benefits from using electric powertrains with their incredible power-to-weight ratio and instant torque. The benefits of using electric vehicles over conventional ones can be seen during the use phase, with zero tailpipe emissions and clean, silent riding.   However, with the expansion of the electric motorcycle sector rolling out new technologies and models, there are uncertainties about whether the overall lifecycle has reduced impacts on the environment. Finding and improving the most sustainable model(s) or solution(s) implies scrutinizing the effects of these motorcycles on the environment, which is the goal of CAKE 0 Emission AB, a Swedish lightweight electric motorbike manufacturer.   The current project will assess the potential environmental impacts of Kalk&, an off-road electric motorcycle model certified for on-road use, designed, and manufactured by CAKE 0 Emission AB. For this purpose, Attributional Life Cycle Assessment was chosen as the method to study the impact of one whole motorbike over a lifetime of 500 battery charging cycles, used by a hypothetical example user in Stockholm, Sweden. The potential environmental impacts are focused on 12 categories using the ReCiPe Midpoint (H) method.   As expected from an electric vehicle, the results show that the impacts mainly stem from the manufacturing phase of the motorbike. The hotspots in the manufacturing phase arise from producing the battery, the electric motor, and the electrical components like lights, the charger, and cables. The materials used for construction that have a high share of impact are Copper and Aluminium. Another environmental hotspot is the casting manufacturing process. Within the vehicle use phase, the impact of using solar energy in Sweden for charging the batteries is not immediately intuitive and has shown to be higher than the Swedish electricity board mix; the results argue that the choice of electricity is vital in reducing emissions. Transporting the vehicle overseas by ship instead of by flight decreases emissions by about 82% to 97% within the various impact categories.   A sensitivity scenario was created for a hypothetical user in Barcelona, Spain, to better understand the influence of the selected lifetime and user behavior on the impacts. The results indicate that using an additional battery and thereby increasing the lifetime of the vehicle shows a 34% decrease in emissions per km driven within the lifetime of the motorcycle. Lastly, it is recommended whenever possible to source the numerous components of the vehicle closer to the assembly unit to reduce the transportation impacts incurred from transoceanic freight. / Företagens elfordonssegment har breddats och deras försäljning har ökat under det senaste decenniet. Den elektriska motorcykelsektorn växer snabbt, med förbättrad teknik på elektriska drivlinor, ökade räckvidder, laddningshastigheter och infrastruktur. Parallellt med den ökade försäljningen går elbatterisektorn snabbt framåt, vilket minskar miljöpåverkan från dessa fordon. Den konkurrensutsatta äventyrssportsektorn drar också nytta av att använda elektriska drivlinor med deras otroliga kraft-till-vikt-förhållande och omedelbara vridmoment. Fördelarna med att använda elfordon framför konventionella kan ses under användningsfasen, med noll avgasutsläpp och ren, tyst körning.  Men med expansionen av elmotorcykelsektorn som rullar ut nya tekniker och modeller, finns det osäkerheter om huruvida den övergripande livscykeln har minskat miljöpåverkan. Att hitta och förbättra de mest hållbara modellerna eller lösningarna innebär att man granskar dessa motorcyklars effekter på miljön, vilket är målet för CAKE 0 Emission AB, en svensk lättviktstillverkare av elmotorcykel.  Det aktuella projektet kommer att bedöma de potentiella miljöeffekterna av Kalk&, en terrängmodell av elektrisk motorcykel certifierad för användning på väg, designad och tillverkad av CAKE 0 Emission AB. För detta ändamål valdes Attributional Life Cycle Assessment som metoden för att studera effekten av en hel motorcykel under en livstid på 500 batteriladdningscykler, som används av en hypotetisk exempelanvändare i Stockholm, Sverige. Den potentiella miljöpåverkan är fokuserad på 12 kategorier med hjälp av metoden ReCiPe Midpoint (H).  Som förväntat av ett elfordon visar resultaten att effekterna huvudsakligen härrör från motorcykelns tillverkningsfas. Hotspots i tillverkningsfasen uppstår från att producera batteriet, elmotorn och de elektriska komponenterna som lampor, laddare och kablar. De material som används för konstruktion som har en hög andel av påverkan är koppar och aluminium. En annan miljömässig hotspot är tillverkningsprocessen för gjutning. Inom fordonsanvändningsfasen är effekten av att använda solenergi i Sverige för att ladda batterierna inte direkt intuitiv och har visat sig vara högre än den svenska elkortsmixen; resultaten talar för att valet av el är avgörande för att minska utsläppen. Att transportera fordonet utomlands med fartyg istället för med flyg minskar utsläppen med cirka 82% till 97% inom de olika påverkanskategorierna.  Ett känslighetsscenario skapades för en hypotetisk användare i Barcelona, Spanien, för att bättre förstå inverkan av den valda livslängden och användarbeteendet på effekterna. Resultaten indikerar att användning av ett extra batteri och därmed ökad livslängd på fordonet visar en 34% minskning av utsläppen per körd km under motorcykelns livslängd. Slutligen rekommenderas det när det är möjligt att köpa de många komponenterna i fordonet närmare monteringsenheten för att minska transportpåverkan från transoceanisk frakt.  Note: The abstract has been translated to Swedish from English using Google Translate
35

Textilproduktionens miljöpåverkan : en studie om koldioxidavtryck, vatten- ochenergianvändning mellan två hemtextil produkter i bomull från olika länder / The environmental impact of textile production : a study on carbon footprint, water andenergy use between two home textile products in cotton from different countries

Tran, Jenny, Nguyen, Linda January 2022 (has links)
Textil- och klädindustrin är identifierad som en av dem största bidragande faktorerna som frigör växthusgaser över hela världen. Produktionen har en lång och komplex försörjningskedja vilket redan från råvaruutvinning släpper ut enorma mängder växthusgaser. Den här kandidatuppsatsen går igenom hela försörjningskedjan för hemtextilsektorn vad gäller olika processer från fiber till färdiga produkter och deras miljöpåverkan. Den undersöker miljöpåverkan från olika stadier i textilprodukters livscykel från vaggan till graven. Uppsatsen belyser också konceptet och principerna för mätning av koldioxidavtryck, vatten och energianvändning för hemtextilprodukter, metoder för att mäta det och dess tillämpning i textilförsörjningskedjan. I produktens livscykelanalys beräknas avtrycket från resursutvinning (vagga) till fabriksporten (grind), i de faserna inkluderas försörjning av fiber, trim och förpackning, textilbearbetning, transporter i produktion, lagring och förpackning, samt distribution. Syftet med arbetet är att beräkna koldioxidavtryck, vatten- och energianvändning och jämföra mellan två påslakanset i 100% bomull tillverkade i två olika länder. Studien ämnar ge en bättre förståelse kring koldioxidutsläppen och miljöpåverkan som dessa produkter frigör under produktion. För att senare kunna jämföras, analyseras och föreslå eventuella förbättringar för att minska produktionens utsläpp. / The textile and clothing industry has been identified as one of the biggest contributing factors to greenhouse gas emissions worldwide. Production has a long and complex supply chain, which already emits enormous amounts of greenhouse gases from raw material extraction. This bachelor's thesis goes through the entire supply chain for the home textile sector in terms of various processes from fiber to finished products and their environmental impact. It examines the environmental impact from different stages in the life cycle of textile products from the cradle to the grave. The thesis also highlights the concept and principles for measuring carbon footprint, water and energy use for home textile products, methods for measuring it and its application in the textile supply chain. The product life cycle analysis calculates the footprint from resource extraction (cradle) to the factory gate (gate), in which phases supply of fiber, trim and packaging, textile processing, transport in production, storage and packaging, and distribution are included. The purpose of the work is to calculate the carbon footprint, water and energy use and compare between two duvet cover sets in 100% cotton made in two different countries. The study aims to provide a better understanding of the carbon dioxide emissions and environmental impact that these products release during production. In order to later be able to compare, analyze and suggest possible improvements to reduce production emissions.
36

Strategic Life-Cycle Modeling and Simulation for Sustainable Product Innovation

Ny, Henrik January 2009 (has links)
Many specific methods and tools have been developed to deal with sustainability problems. However, without a unifying theory it is unclear how these relate to each other and how they can be used strategically. A Framework for Strategic Sustainable Development (FSSD) is being developed to cover this need for clarity and structure. It includes backcasting from a principled definition of sustainability as a key feature. The aim of this thesis is to study how this framework can guide the use and improvement of detailed methods and tools, in particular to support sustainable product innovation (SPI). First, a new strategic life-cycle management approach is presented, in which the selection of aspects to be considered are not based on typical down-stream impact categories, but on identified major violations of sustainability principles. Ideas of how this approach can inform various specific methods and tools are also presented, as a basis for an integrated “toolbox” for SPI. As part of such, a new “template” approach for sustainable product development (TSPD) is developed through a sustainability assessment case study of TVs. That study indicates that this approach can create a quick and strategically relevant overview of critical sustainability aspects of a product, as well as facilitate communication between top management, product developers and external stakeholders. Based on such an assessment, it is sometimes necessary to go deeper into details, including the use of specific engineering methods and tools. To facilitate a coordinated assessment of sustainability aspects and technical aspects, an introductory procedure for sustainability-driven design optimization is suggested trough a water jet cutting case study. Equally important, to get a breakthrough for SPI, it is essential to integrate sustainability aspects into the overall decision-making process at different levels in companies. An approach to assessing sustainability integration in strategic decision systems is therefore also developed through a case study involving several companies. Finally, the integration between the FSSD and general systems modeling and simulation (SMS) is discussed and tested in another water jet cutting case study. It is shown feasible to start with the FSSD to create lists of critical flows and practices, ideas of long term solutions and visions, and a first rough idea about prioritized early investments. After that, SMS can be applied to study the interrelationships between the listed items, in order to create more robust and refined analyses of the problems at hand, possible solutions and investment paths, while constantly coupling back to the sustainability principles and guidelines of the FSSD. This research shows that the combination of the FSSD with detailed methods and tools cohesively provides decision-makers with both a robust overview and, when needed, a more coordinated and effective detailed support. To utilize its full potential, this approach should now be integrated into decision processes, software and manuals for SPI.
37

Model upravljanja uticajima procesa proizvodnje podnih obloga na životnu sredinu primenom metode ocenjivanja životnog ciklusa (LCA) / Model for management of environmental impacts from flooring's production processes by the application of life cycle assessment (LCA)

Vještica Sunčica 15 April 2014 (has links)
<p>U disertaciji je predložen opšti model za upravljanje uticajima na životnu sredinu u okviru proizvodnih procesa proizvodnje podnih obloga, zasnovan na metodi ocenjivanja životnog ciklusa proizvoda i procesa. Model je sistematično predstavljen kroz opis osnovnih delova - modela inventara životnog ciklusa i modela za ocenjivanje uticaja životnog ciklusa. Disertacija sadrži i detaljan opis podloga na kojima je model razvijen. Verifikacija razvijenog modela je sprovedena kroz tri studije slučaja.</p> / <p>The dissertation proposes a general model for managing environmental impacts within the manufacturing process of flooring coverings, based on the method of life cycle assessment of products and processes. The model is systematically present by describing the main parts - the life cycle inventory model and a model for the life cycle impact assessment. Dissertation contains a detailed description of the background bases on which the model is developed. Verification of the model is carried out through three case studies.</p>
38

Improving microalgae biofuel production : an engineering management approach

Mathew, Domoyi Castro January 2014 (has links)
The use of microalgae culture to convert CO2 from power plant flue gases into biomass that are readily converted into biofuels offers a new frame of opportunities to enhance, compliment or replace fossil-fuel-use. Apart from being renewable, microalgae also have the capacity to utilise materials from a variety of wastewater and the ability to yield both liquid and gaseous biofuels. However, the processes of cultivation, incorporation of a production system for power plant waste flue gas use, algae harvesting, and oil extraction from the biomass have many challenges. Using SimaPro software, Life cycle Assessment (LCA) of the challenges limiting the microalgae (Chlorella vulgaris) biofuel production process was performed to study algae-based pathway for producing biofuels. Attention was paid to material use, energy consumed and the environmental burdens associated with the production processes. The goal was to determine the weak spots within the production system and identify changes in particular data-set that can lead to and lower material use, energy consumption and lower environmental impacts than the baseline microalgae biofuel production system. The analysis considered a hypothetical transesterification and Anaerobic Digestion (AD) transformation of algae-to- biofuel process. Life cycle Inventory (LCI) characterisation results of the baseline biodiesel (BD) transesterification scenario indicates that heating to get the biomass to 90% DWB accounts for 64% of the total input energy, while electrical energy and fertilizer obligations represents 19% and 16% respectively. Also, Life Cycle Impact Assessment (LCIA) results of the baseline BD production scenario show high proportional contribution of electricity and heat energy obligations for most impact categories considered relative to other resources. This is attributed to the concentration/drying requirement of algae biomass in order to ease downstream processes of lipid extraction and subsequent transesterification of extracted lipids into BD. Thus, four prospective alternative production scenarios were successfully characterised to evaluate the extent of their impact scenarios on the production system with regards to lowering material use, lower energy consumption and lower environmental burdens than the standard algae biofuel production system. A 55.3% reduction in mineral use obligation was evaluated as the most significant impact reduction due to the integration of 100% recycling of production harvest water for the AD production system. Recycling also saw water demand reduced from 3726 kg (freshwater).kgBD- 1 to 591kg (freshwater).kgBD- 1 after accounting for evaporative losses/biomass drying for the BD transesterification production process. Also, the use of wastewater/sea water as alternative growth media for the BD production system, indicated potential savings of: 4.2 MJ (11.8%) in electricity/heat obligation, 10.7% reductions for climate change impact, and 87% offset in mineral use requirement relative to the baseline production system. Likewise, LCIA characterisation comparison results comparing the baseline production scenarios with that of a set-up with co-product economic allocation consideration show very interesting outcomes. Indicating -12 MJ surplus (-33%) reductions for fossil fuels resource use impact category, 52.7% impact reductions for mineral use impact and 56.6% reductions for land use impact categories relative to the baseline BD production process model. These results show the importance of allocation consideration to LCA as a decision support tool. Overall, process improvements that are needed to optimise economic viability also improve the life cycle environmental impacts or sustainability of the production systems. Results obtained have been observed to agree reasonably with Monte Carlo sensitivity analysis, with the production scenario proposing the exploitation of wastewater/sea water to culture algae biomass offering the best result outcome. This study may have implications for additional resources such as production facility and its construction process, feedstock processing logistics and transport infrastructure which are excluded. Future LCA study will require extensive consideration of these additional resources such as: facility size and its construction, better engineering data for water transfer, combined heat and power plant efficiency estimates and the fate of long-term emissions such as organic nitrogen in the AD digestate. Conclusions were drawn and suggestions proffered for further study.
39

Consideration of life cycle energy use and greenhouse gas emissions for improved road infrastructure planning

Miliutenko, Sofiia January 2016 (has links)
Global warming is one of the biggest challenges of our society. The road transport sector is responsible for a big share of Greenhouse Gas (GHG) emissions, which are considered to be the dominant cause of global warming. Although most of those emissions are associated with traffic operation, road infrastructure should not be ignored, as it involves high consumption of energy and materials during a long lifetime. The aim of my research was to contribute to improved road infrastructure planning by developing methods and models to include a life cycle perspective. In order to reach the aim, GHG emissions and energy use at different life cycle stages of road infrastructure were assessed in three case studies using Life Cycle Assessment (LCA). These case studies were also used for development of methodology for LCA of road infrastructure. I have also investigated the coupling of LCA with Geographic Information Systems (GIS) and the possibility to integrate LCA into Environmental Impact Assessment (EIA) and Strategic Environmental Assessment (SEA). The results of the first case study indicated that operation of the tunnel (mainly, lighting and ventilation) has the largest contribution in terms of energy use and GHG emissions throughout its life cycle. The second case study identified the main hotspots and compared two methods for asphalt recycling and asphalt reuse. The results of the third case study indicated that due to the dominant contribution of traffic to the total impact of the road transport system, the difference in road length plays a major role in choice of road alternatives during early planning of road infrastructure. However, infrastructure should not be neglected, especially in the case of similar lengths of road alternatives, for roads with low volumes of traffic or when they include bridges or tunnels. This thesis contributed in terms of foreground and background data collection for further LCA studies of road infrastructure. Preliminary Bill of Quantities (BOQ) was identified and used as a source for site-specific data collection. A new approach was developed and tested for using geological data in a GIS environment as a data source on earthworks for LCA. Moreover, this thesis demonstrated three possible ways for integrating LCA in early stages of road infrastructure planning. / <p>QC 20160329</p>
40

Posuzování vlivu na životní prostředí při konstrukci výrobních strojů z pohledu emise vybraných skleníkových plynů / Assesment of the Environmental Impact in the Design of Production Machines in Terms of Greenhouse Gas Emissions of Selected

Krbalová, Maria Unknown Date (has links)
The presented doctoral thesis is focused on environmental impact assessment of basic engineering materials used in a production machine construction. Ecological profile of the machine itself develops already in the phase of its design. It is not only about the choice of future machine parameters and materials that it is built from, but also about technologies used for its manufacture and operation conditions of the finished machine (consumption of energy and service fluids). The thesis occupies in detail with environmental impact analysis of the production machine design from the viewpoint of material production that mentioned machine consists of. The output from the performed analysis is methodology for evaluating of machine design from the viewpoint of greenhouse gas emissions. Created methodology enables evaluating of machine ecological profile and its possible adjustments even during pre-production stage. In the first part of the thesis the analysis of current legislation in the field of fighting against climate changes, reducing of products energy consumption and increasing of production machines energy efficiency is presented. Also in this part of the thesis description of methods that were used to achieve thesis goals is stated. Furthermore analysis of production machine as a system of structural components that fulfil the certain functions and description of used basic engineering materials are presented. The second part of the thesis is devoted to environmental impact analysis of the production machine design process. There the design process and environmental impact of machine design are described. This is followed by description of production machine life cycle and detailed analysis of undesirable substances emissions emitted during pre-production phases of machine life cycle (i.e. during the raw materials extraction and materials production). From this analysis the particular constituents’ pre-production phases which are sources of undesirable substances emissions (e.g. greenhouse gas emissions) were derived. The thesis also includes analysis of these constituents’ life cycles and description of electric power generation as a basic constituent of any phase of product life cycle. In this part of the thesis calculations of particular fuel type’s amounts that is required to produce 1 MWh of electric power and carbon dioxide amount produced during electric power generation are presented. The third part of the thesis contains created models of manufacturing processes of basic engineering materials and calculations of related emissions of selected greenhouse gases. The practical output from this part of the thesis is methodology that enables environmental impact assessment of machine design from the viewpoint of engineering materials used in its construction.

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