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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.
231

Wooden Photovoltaic Module Frames : Proof of Concept, Life Cycle Assessment and Cost Analysis

Singer, Tanyew January 2021 (has links)
To mitigate climate change and to achieve global carbon neutrality, the expansion of renewable energy sources is of paramount importance. In this context, photovoltaics (PV) are widely regarded as one of the most promising technologies to lead the transformation towards decarbonized energy systems. However, the manufacturing of PV systems is associated with initial greenhouse gas emissions linked to the procurement of PV components. Therefore, current research focuses on minimizing initial emissions to improve the overall environmental performance of PV systems. Since previous research suggests that conventional aluminum module frames contain a significant amount of embodied carbon, this study investigates a possible material substitution with wood as alternative frame material to lower the overall carbon footprint of PV modules.  To test the technical feasibility of PV modules with wooden frames, a proof of concept (POC) is conducted using wood types that exhibit necessary characteristics regarding their mechanical properties and durability. Guided by the finite element method and preliminary testing, a novel frame design is conceived, and PV modules with wooden frames are realized. The prototypes are put to extensive testing, in which the mechanical stability is examined, and weathering effects are investigated in an outdoor installation. Furthermore, a life cycle assessment (LCA) is carried out to quantify potential benefits of wooden compared to aluminum frames regarding their global warming potential and other environmental impact categories. Lastly, this study compares the economic performance of wooden PV module frames with aluminum frames and considers possible optimizations in the value chain of wooden frames. POC results show that PV modules with wooden frames - in line with industrial standards - are feasible, yet mechanical stability and durability vary depending on the type of wood and overall design. LCA results suggest that wooden frames exhibit invariably better environmental performance in all impact categories although a reduced module lifetime may impair the overall life cycle performance. In regard to cost efficiency, wooden frames are more costly than aluminum frames, yet financial incentives or subsidies may make low-carbon materials more competitive in the future. It can be concluded that wooden PV module frames may be a promising alternative to standard aluminum frames provided that the overall lifetime is identical. Thus, additional studies are required to analyze the long-term performance and to identify areas of application for modules with wooden frames, for instance in the building-integrated PV sector. Lastly, further research is needed to explore additional utilizations of wood in PV systems such as in ground and roof mounting structures.
232

Generating Product-Service Design Improvements from a Climate Impact and Energy Use Perspective Using Life Cycle Assessment : The Case of Vertical Access Equipment

Tirumalasetty, Vishnu Teja, Bäck, Max Olof Jonas January 2021 (has links)
Climate change is connected to several negative effects on local environments around the globe such as, longer, and more intense droughts, less freshwater supplies, ocean warming, sea level rise, polar ice melting, more intense storms, and rainfall (NASA, 2021).  These problems are mainly due to the increasing amount of carbon dioxide in the atmosphere as well as other greenhouse gases (GHG) which cause a similar or stronger climate change effect (WWF, 2021). Practically all climate researchers agree that climate change is caused by human activities (WWF, 2021), as such human activities will have to change to reduce their climate impact. One possible approach to achieve sustainable products is the concept of a circular economy (CE). The proponents of a circular economy describe it as an economic or industrial system which is restorative by its design (EMF, 2010). Currently there is a substantial body of knowledge on how LCA can be used to guide product design in a sustainable direction.  However, as of yet there are limited academic research focused on how environmental assessment can impact the design of Vertical Access Equipment (VAE) and of similar products. This thesis aims to support the VAE sector’s transition towards a CE. The objective of this study was to understand and provide improvement suggestions for the environmental performance and energy use of VAE. This Involved a case study where a LCA was conducted to establish a baseline of four VAE products, a construction hoist, a service lift, an industrial elevator, and a BMU. The results of the initial LCA varied greatly depending on the different products and their use case. Guided by the LCA results, semi-structured workshops were held to find feasible improvement suggestions whose impacts were investigated using LCA once more. Feasible and substantial improvements focusing on the products high impact areas were found for all products. For the construction hoist improvements regarding eliminating waste in the lifting work was most impactful, whilst the service lift required optimizing of maintenance and use of sensors to reduce the maintenance time. For the industrial elevator and the BMU, measures which focused on reducing virgin material extraction showed most promise, such as lifespan extension, remanufacturing, and use of recycled materials. / Mistra REES
233

Sustainable shrimp production chain in the Midwestern United States

Ahmad Al Eissa (8815262) 08 May 2020 (has links)
<p>With the increasing global population, providing sufficient food to meet the rising demand has become a great challenge to food-producing sectors. Aquaculture is one of the food sources which produces varieties of seafood. Shrimp is the most popular seafood in the US, and its production plays an important role in the aquaculture industry. However, shrimp farming causes various types of pollution to damage the environment and aquatic biodiversity, the associated impacts must be mitigated to ensure the sustainability of shrimp production. This study performed a life cycle assessment (LCA) on different shrimp production chains from cradle to the market in Midwestern US covering three farming systems and eight shrimp feed formulas. Midpoint environmental impacts including acidification potential (AP), eutrophication potential (EP) and global warming potential (GWP) were determined. Feed production was identified as the main contributor to the AP and GWP for both the intensive and semi-intensive production systems (SPS), regardless of the feed formula. While the environmental performance of feed production highly depended on the feed conversion ratio, feed ingredient was another determining factor in which animal protein sources, including poultry by-product meal and fishmeal, showed high contributions to the AP and GWP. However, plant proteins such as soybean, wheat, and corn gluten meals produced higher EP, therefore, substituting plant-based ingredients for animal-based ones in shrimp feeds did not all result in positive environmental consequences. Shrimp farming was the hotspot of all the three impacts, especially accounting for the highest EP. Among the three farming systems studied here, the SPS caused the highest environmental burdens due to the intensive uses of chemicals and fertilizers. On the contrary, the extensive farming was found to be the most sustainable system because no inputs of feeding and additional materials and energy are required for its operation. The LCA model developed in this study is expected to serve as US shrimp farmers’ decision-making guidelines to adapt farming practices with lower environmental footprint.<br><a></a></p>
234

Development of a methodology of Dynamic LCA applied to the buildings / Développement d’une méthodologie d’ACV dynamique appliquée aux bâtiments

Negishi, Koji 21 June 2019 (has links)
Le secteur du bâtiment est un acteur clé pour aider la France à atteindre ses objectifs de réduction en matière de consommation d’énergie et d’émissions de gaz à effet de serre (GES). L’analyse du cycle de vie (ACV) est la méthode la plus utilisée pour évaluer les impacts environnementaux d’un produit ou d’un système d’une manière systématique et holistique sur l’ensemble de son cycle de vie. Dans le secteur du bâtiment, la méthode ACV a été adaptée avec des outils appropriés, simplifiés, pour inciter les acteurs du bâtiment à évaluer la performance environnementale de leur produit. Cependant, la méthode ACV présente des limites dont une est le manque de notion de « temps », qui touche notamment trois points : (i) Manque de considération de l’évolution temporelle des systèmes, du système « bâtiment » dans notre cas, (ii) Non prise en compte du décalage temporel des activités et donc des émissions, and (iii) Non prise en compte du caractère dynamique des impacts environnementaux. Dans ce contexte, l’objectif de la thèse est de développer une méthodologie d’ACV dynamique appliquée au bâtiment, qui permet de prendre en compte ces trois aspects dynamiques, sur la base du projet ANR DyPLCA. L’application de la nouvelle méthode dynamique à un cas d’étude avec trois maisons individuelles accolées a permis d’obtenir des informations importantes sur le profil temporel des impacts. La même quantité des émissions de GES a un impact de changement climatique plus bas lorsque les émissions sont réparties sur une période longue. Les actions pour la réduction et l’adaptation doivent être décidées selon différents types de famille de produits de construction. Ainsi, il est nécessaire d’adapter les efforts de réduction d’impacts en fonction des substances chimiques. / The building sector is a key actor to meet the reduction targets in terms of energy consumption and greenhouse gases (GHG) emissions. Life Cycle Assessment (LCA) is the most used method for assessing the environmental impacts of a system. In the building sector, the LCA method was adapted with appropriate and simplified tools in order to encourage stakeholders to evaluate the environmental performance of their building products. However, LCA method has some limitations, one of which being the lack of “time dimension” that particularly concerns three points: (i) Lack of consideration of temporal evolution of the system under LCA study, “building system” in our case, (ii) Lack of consideration of temporal discrepancy of activities and associated emissions, (iii) Lack of consideration of dynamic characteristics of environmental impacts (stationary conditions, fixed time horizon, etc.). In this context, the primary objective of the thesis is to develop a dynamic LCA methodology applied to the building sector, on the basis of DyPLCA ANR project. The application of the new dynamic method to a case study with three attached single houses demonstrated that dynamic LCA provides important information on the temporal profile of impacts. The same amount of GHG emissions has a lower effect on temperature peaks when emissions are spread over a long period. The distinction is made between the various GHG, especially according to their lifetime. Instantaneous and cumulated effects (indicators) should be considered in a complete analysis. Actions for mitigation and adaptation need to be decided according to different types of construction product families. Besides, it is necessary to adapt the impact reduction efforts according to the chemical substances.
235

Socio-economic assessment of wood-based products from German bioeconomy regions:: a social life cycle assessment approach

Siebert, Anke 06 August 2019 (has links)
The effort on mitigating climate change has conjured up a vision of a bioeconomy. Therefore, industrial production has to turn away from fossil-based resources to bio-based ones. In Germany, the BioEconomy Cluster aims to establish a bioeconomy region that is based on non-food biomass, especially wood. The complexity of this transition raises doubts as to whether it necessarily leads to a better, more sustainable living in the regions. Currently, life cycle assessment tools are viewed as adequate to evaluate sustainability aspects associated to products. A method to analyse potential social effects of products is at an early stage. Therefore, this PhD thesis develops a social life cycle assessment approach to assess wood-based production systems in a bioeconomy region in Germany. A framework was formulated with major concepts and definitions applied. The goal and scope comprise to identify of social hotspots and opportunities of the foreground activities involved in a production system in a German bioeconomy region. The system boundary was defined as an area smaller than a country and major stakeholder categories were selected. In addition the organisations’ conduct was determined as the main unit of analysis. Based on the frameworks’ major elements a social indicator set with seven social indices (e.g. health & safety; participation) and 32 social indicators (e.g. accidents) was selected to make the inventories. Therefore, sustainability standards and sLCA case studies were screened and stakeholder interviews were conducted to set up a final set. Within this PhD thesis context-specific performance reference points (PRPs) were determined for the sLCIA phase. Compared with the organisations’ indicator values, they indicate a “relatively poor” or “relatively better” social performance (i.e. a social opportunity or hotspot). The PRPs considered the classification of economic sector of the assessed organisation and in some cases the size of the organisation as factors influencing the potential social effects. The framework provides major elements (i.e. a context-specific indicator set and characterisation approach) to assess relevant social effects associated with the organisations production activities involved in a products production. Therefore, the sLCA approach supports producer’s decision making which may mitigate negative social effects and accelerate positive ones.:Summary i Acknowledgements ii List of Publications vii List of Figures ix List of Tables xii List of Abbreviations xiii 1 Introduction 1 1.1 Bioeconomy and sustainability 1 1.2 The BioEconomy Cluster 2 2 Social Life Cycle Assessment, S-LCA 3 2.1 The history of sLCA 3 2.2 The UNEP-SETAC guidelines 4 2.3 Review on sLCA 5 2.3.1 Goal and scope definition 8 2.3.2 Social life cycle inventory 9 2.3.3 Characterisation 10 3 Research question and aim of the thesis 12 4 Social life cycle assessment: in pursuit of a framework for assessing wood-based products from bioeconomy regions in Germany 14 4.1 Abstract 14 4.2 Introduction 15 4.2.1 Germany’s wood-based bioeconomy 15 4.2.2 Social life cycle assessment 16 4.2.3 Goal and structure of the paper 17 4.3 Defining the goal and scope 17 4.3.1 Defining the goal—the purpose of the developed sLCA approach 17 4.3.2 Regional system boundaries 18 4.3.3 The production system 19 4.3.4 Stakeholder categories 19 4.3.5 Defining and using a functional unit 20 4.3.6 Activity variables—relating social effects to the product 21 4.3.7 Social indices and indicators 22 4.3.8 Developing context-specific social indices and indicators 23 4.3.9 Presenting the social effects to regional producers 24 4.4 Social life cycle inventory (sLCI) 25 4.4.1 SLCIs in global hotspot assessment studies 25 4.4.2 SLCIs in regional hotspot assessment studies 26 4.5 Social life cycle impact assessment (sLCIA) 27 4.5.1 Characterisation method: international PRPs 28 4.5.2 Characterisation method: national PRPs 28 4.5.3 Characterisation method: sector PRPs 29 4.5.4 Characterisation method: regional PRPs 29 4.6 An sLCA framework for regional bioeconomy chains 31 4.7 Summary and outlook 33 5 Social life cycle assessment indices and indicators to monitor the social implications of wood-based products 35 5.1 Abstract 35 5.2 Introduction 36 5.3 Materials and methods 38 5.3.1 Screening criteria 38 5.3.2 Overview of research steps 40 5.3.3 Screening of global sustainability standards 41 5.3.5 Screening of national sustainability and forest certification standards 43 5.3.6 Screening of sLCA case studies 43 5.3.8 Stakeholder interviews 44 5.3.9 Selection based on feasibility of implementation 46 5.4 Results and discussion 48 5.4.1 Index: health and safety 52 5.4.2 Index: adequate remuneration 52 5.4.3 Index: adequate working time 53 5.4.4 Index: employment 53 5.4.5 Index: knowledge capital 54 5.4.6 Index: equal opportunities 55 5.4.7 Index: participation 56 5.5 Outlook 56 5.6 Conclusion 57 6 How not to compare apples and oranges: Generate context-specific performance reference points for a social life cycle assessment model 59 6.1 Abstract 59 6.2 Introduction 60 6.2.1 Background 60 6.2.2 The RESPONSA framework 61 6.2.3 Goal of this work 64 6.3 Influence factors recognised in the context-specific characterisation approach for the German wood-based bioeconomy 65 6.3.1 Classification of the influential conditions 65 6.3.2 The geographical location 68 6.3.3 The economic sector 68 6.3.4 The size of the organisation 69 6.4 The scoring approach and data sources 69 6.4.1 The scoring approach 69 6.4.2 Data sources to determine PRPs 70 6.5 Characterisation approach for quantitative indicators 70 6.5.1 Characterisation of quantitative indicators (full data) 70 6.5.2 Characterisation of quantitative indicators (partial data) 71 6.6 Characterisation approach for qualitative indicators 73 6.6.1 Characterisation of qualitative indicators with binary answers on a sectoral level 73 6.6.2 Characterisation of qualitative indicators with ranked answers on a sectoral level 74 6.6.3 Characterisation of qualitative indicators on a sectoral and organisational size level 76 6.7 Exemplary case study 77 6.7.1 Classifying organisations in the product system 77 6.7.2 Determining the sLCIs 78 6.7.3 sLCIA step 78 6.7.4 Relating social effects to the product 81 6.7.5 Discussion of the results 83 6.8 Discussion and outlook 84 6.9 Conclusion 85 7 Discussion of the main results 87 7.1 Organisations as unit of analysis 87 7.2 A country as major system boundary 88 7.3 A context-specific indicator set 89 7.4 Impact assessment: Economic sector and organisational size PRPs 90 7.5 The interpretation of the results 92 7.6 Limitations of the approach 94 7.7 Use for the Cluster 95 7.8 Outlook 96 8 Conclusion 97 9 Use of RESPONSA – A REgional SPecific cONtext-ualised Social life cycle Assessment tool 100 9.1 The RESPONSA user interface 100 9.1.1 Inputs from the organisations 101 9.1.2 The calculation made by RESPONSA 102 9.1.3 Output for the organisation 103 References cv Appendix A cxiii Appendix B cxx Appendix C cxxiv CURRICULUM VITAE cxxviii Author contribution cxxx Eigenständigkeitserklärung cxxxiii Bibliographische Beschreibung cxxxiv
236

Koldioxidreducerad betong : Med betongens egenskaper bibehållna

Hermansson Ali, Aland January 2020 (has links)
This study will explore if, and if so how, a transition into a more sustainable and eco-friendly ordinary portland cement can be made, without damaging its fundamental strengths and properties. The core concept essence of this degree project focuses on a comparison between four central properties of fly ash in portland cement with those of ordinary portland cement: the chloride-induced penetration, alkali reactivity, frost resistance and strength. The study will attempt to describe what measures the concrete industry are taking on the path towards a non-fossil future, following a sort of a roadmap. The process of making concrete is a major contributor to CO2 emissions, and the process is energy-intensive. The changing climate is affecting every living thing on this planet in a negative way, and in the end, there will be devastating consequences for all the different sectors of society if we cannot change our ways of using natural resources. Because of its current carbon footprint, the construction industry has a long way to go before reaching its non-fossil vision. A literature study was carried out to determine if concrete’s current properties and solidity could be retained when making a non-fossil concrete, or at least a more eco-friendly one. The alternative admixture fly ash decreased the amount of water needed and reduced the amount of clinker particles used in making concrete. This leads to a decreased usage of fossil fuel in the production process, without actually affecting the actual life span of the concrete negatively. In fact, use of fly ash improves the concrete a longer life span. Another vital measurement that can be taken is to use the technique called CCS, which leads to a decreased amount of pollution in the production process. The Swedish construction industry is determined to reach their non fossil vision. There is a strong belief that a life without being dependent on fossil fuel is a better life, and this will hopefully lead to a global race towards achieving sustainability. The result of this study shows that the current development within the industry is eco-positive and will contribute towards a more sustainable future for the concrete industry.
237

Life Cycle Assessment of Portland Cement and Concrete Bridge : Concrete Bridge vs. Wooden Bridge

Mousavi, Marjan January 2013 (has links)
Today global warming mitigation, natural resource conservation and energy saving are some of the significant concerns of different industries, such as cement and concrete industries. For that reason, a streamlined life cycle assessment (LCA) model of one ton of a Portland cement, CEM I produced in Cementa AB’s Degerhamn plant, has been developed by using the LCA software KCL-ECO. LCA is a tool that identifies in which stages of a product’s life cycle the most environmental burdens occur. The environmental analysis was limited to identify total energy consumption and total carbon dioxide (CO2) emissions per ton of Portland cement. Results show that the most significant energy consumption and CO2 emissions are related to clinker kiln, due to the process of calcination of limestone and fuel combustion in the kiln. Of total CO2 emissions, 52 % and 46 % result from the calcination process and fuel combustion respectively.  One of the applications of CEM I is in construction of concrete bridges. Therefore an LCA model of a concrete bridge located north of Stockholm was developed in KCL-ECO. Environmental indicators calculated are: total CO2 emissions and energy consumption through the entire life cycle of the bridge. CO2 uptake or carbonation of the concrete during the service life of the product and end of life treatment is one of the advantages of concrete products. During the carbonation process, some of the total CO2 released from calcination will be absorbed into the concrete. Results indicate that production of raw materials and transports during the life cycle of the concrete bridge, are main contributors to total CO2 emissions. Among raw materials, cement production has the highest CO2 emissions. Energy consumption is mainly related to concrete and concrete products production. CO2 uptake during the use phase of the bridge is small compared to total CO2 emissions from calcination. Furthermore, the results show that different waste handling practises result in different CO2 uptake behaviours. The total CO2 uptake from crushing and storing of the demolished concrete (scenario 1) and landfilling of the demolished concrete (scenario 2) is 10 % and 5 % of the total CO2 emissions from calcination respectively.  Since comparison of different construction materials from an environmental point of view is always desirable, the LCA tool was used to compare the total energy consumption and the CO2 emissions from a concrete bridge and a wooden bridge. The functional unit was defined as 1 square meter of bridge surface area, since the bridges were of different sizes and shapes. In this comparison the total emissions and energy consumption were much higher for the concrete bridge than for the wooden bridge.  In order to show how different assumptions could affect the results, a virtual concrete bridge with the same shape and size as the wooden bridge was designed and compared with the wooden bridge. The functional unit selected for this case was one bridge. In this case the virtual concrete bridge requires less energy, while the wooden bridge emits less CO2 to the atmosphere. For the wooden bridge, CO2 in growing forests was included, which could be debated. Overall, a comparison of the environmental performance of the wooden bridge and the concrete bridges was more complex than initially expected and great care is recommended in choosing material and application. With concrete, the design (and quantity of material used) seems to be a very sensitive parameter and may result in much larger energy used and CO2 emissions than a wooden bridge. On the other hand, the virtual bridge comparison showed that concrete advantages such as higher durability and lower maintenance may be theoretically combined with a comparable energy and climate performance as a wooden alternative.
238

ASSESSMENT OF MACROALGAE HARVESTING FROM THE BALTIC SEA FROM AN ENERGY BALANCE PERSPECTIVE

Tatarchenko, Olena January 2011 (has links)
Energy balance of large-scale and small-scale scenarios of macroalgae harvesting for biogas production was assessed from the energy balance perspective. Evaluation was based on primary energy Input Output (IO) ratio where all primary energy inputs into the stages of the process life-cycle were summarized and divided by the final energy output from the system. Estimations were made for three cases of possible methane yield from macroalgae as well as for different scenarios of macroalgae co-digestion with other feedstock. Anaerobic digestion of macroalgae as a single substrate both on a small- and large-scale is energy efficient only in case when their methane potential is at the average or high level with the IO ratio of 0.47 and 0.32 correspondently. In general co-digestion with other substrates is more preferable with respect to process condition and energy balance. Large-scale scenario is more stable and efficient than small-scale with the lowest IO ratio for co-digestion with crops. This is explained by the fact that biogas plant operation is among the most energy demanding stages which on the small-scale requires about 65 % of the input energy when this number for large-scale plant does not exceed 28 %. Energy inputs into digestate handling, feedstock pre-treatment and biogas upgrading, that are next most energy consuming stages, is greatly affected by the assumptions made about amount of substrate, produced biogas and transportation distance. When considering the maximal distance between macroalgae harvesting point and biogas production site and to which at which the energy balance remains positive then digestate handling becomes the most energy demanding process stage.
239

A Life Cycle Sustainability Study of Perovskite Solar Cell Technologies

Zhang, Jingyi 23 May 2019 (has links)
No description available.
240

TECHNOLOGICAL AND ENVIRONMENTAL SUSTAINABILITY OF BATTERY-POWERED ELECTRIC VEHICLES

yang, fan 02 June 2020 (has links)
No description available.

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