Global ETD Search

11	Life cycle assessment and life cycle cost analysis of a single-family house Petrovic, Bojana January 2021 (has links) The building industry is responsible for 35% of final energy use and 38% of CO2 emissions at a global level. The European Union aims to reduce CO2 emissions in the building industry by up to 90% by the year 2050. Therefore, it is important to consider the environmental impacts buildings have. The purpose of this thesis was to investigate the environmental impacts and costs of a single-family house in Sweden. In the study, the life cycle assessment (LCA) and the life cycle cost (LCC) methods have been used by following the “cradle to grave” life cycle perspective. This study shows a significant reduction of global warming potential (GWP), primary energy (PE) use and costs when the lifespan of the house is shifted from 50 to 100 years. The findings illustrate a total decrease in LCA outcome, of GWP to 27% and PE to 18%. Considering the total LCC outcome, when the discount rate increases from 3% to 5% and then 7%, the total costs decrease significantly (60%, 85% to 95%). The embodied carbon, PE use and costs from the production stage/construction stage are significantly reduced, while the maintenance/replacement stage displays the opposite trend. Operational energy use, water consumption and end-of-life, however, remain largely unchanged. Furthermore, the findings emphasize the importance of using wood-based building materials due to its lower carbon-intensive manufacturing process compared to non-wood choices. The results of the LCA and LCC were systematically studied and are presented visually. Low carbon and cost-effective materials and installations have to be identified in the early stage of a building design so that the appropriate investment choices can be made that will reduce a building’s total environmental and economic impact in the long run. Findings from this thesis provide a greater understanding of the environmental and economic impacts that are relevant for decision-makers when building single-family houses. / Byggbranschen svarar för 35% av den slutliga energianvändningen och 38 % av koldioxidutsläppen på global nivå. Europeiska unionen strävar efter att minska koldioxidutsläppen i byggnadsindustrin med upp till 90% fram till 2050. Därför är det viktigt att beakta byggnaders miljöpåverkan. Syftet med denna avhandling var att undersöka miljöpåverkan och kostnader för ett enfamiljshus i Sverige. I studien har livscykelbedömningen (LCA) och livscykelkostnadsmetoderna (LCC) använts genom att tillämpa livscykelperspektivet ”vagga till grav”. Studien visar en stor minskning av global uppvärmningspotential (GWP), användning av primärenergi (PE) och kostnader vid växling från 50 till 100 års husets livslängd. Resultaten visar en årlig minskning med 27% för utsläpp av växthusgaser och med 18% för användningen av primärenergi. Med tanke på det totala LCC-utfallet, när diskonteringsräntan ökar från 3%, 5% till 7%, minskar de totala kostnaderna avsevärt (60%, 85% till 95%). Det noteras att klimatavtrycket, primärenergianvändningen och kostnaderna från produktionssteget/konstruktionssteget minskar avsevärt, medan underhålls- / utbytessteget visar den motsatta trenden när man byter från 50 till 100 års livslängd. Den operativa energianvändningen, vattenförbrukningen och avfallshanteringen är fortfarande nästan samma när man ändrar livslängden. Vidare betonar resultaten vikten av att använda träbaserade byggmaterial på grund av lägre klimatpåverkan från tillverkningsprocessen jämfört med alternativen. LCA- och LCC-resultaten studerades systematiskt och redovisades visuellt. De koldioxidsnåla och kostnadseffektiva materialen och installationerna måste identifieras i ett tidigt skede av en byggnadskonstruktion genom att välja lämpliga investeringsval som kommer att minska de totala miljö och ekonomiska effekterna på lång sikt. Resultaten från denna avhandling ger ökad förståelse för miljömässiga och ekonomiska konsekvenser som är relevanta för beslutsfattare vid byggnation av ett enfamiljshus. Building carbon-dioxide equivalent emissions global warming potential primary energy use life cycle assessment life cycle cost Byggnad koldioxidekvivalenta utsläpp global uppvärmningspotential pri-märenergianvändning livscykelbedömning livscykelkostnad Energy Systems Energisystem
12	En studie om konstruktörer kan minska klimatpåverkan av koldioxid från betong via kravspecifikation / A study about if construction designers can reduce the climate impact of carbon dioxide from concrete through specifications Staffansson, Frida January 2019 (has links) Syfte: Byggindustrin kommer framförallt att påverkas av hållbarhetsutvecklingens framfart. FN har satt hållbarhetsmål presenterade i Agenda 2030 och för att möta dessa mål måste hållbarhet stå i fokus för både yrkesverksamma och intressenter. Betong är ett material som består av ballast, vatten och cement som hårdnar över tiden och används världen över inom byggindustrin. År 2014 uppskattades betongproduktionen stå för hela fem procent av alla antropogena koldioxidutsläpp. Syftet med studien är att undersöka miljöpåverkan från olika betongkvaliteter mätt i koldioxidekvivalenter och använda resultatet för att påvisa om konstruktörer kan göra någon skillnad via sina kravspecifikationer på betong. Metod: En litteraturstudie genomfördes inledningsvis för att säkerställa studiens relevans samt skapa kunskap kring området. LCA och dokumentanalys av EPD möjliggjorde jämförelse av klimatpåverkan och data kunde sammanställas. Resultat: Sammanställd och jämförd data från LCA och dokumentanalys tyder på att konstruktörer kan minska klimatpåverkan genom att föreskriva högre vct och lägre exponeringsklass. Detta möjliggör att en större andel cement kan bytas ut mot tillsatsmaterial. Litteraturstudie tyder på att konstruktörens arbete för att minska klimatpåverkan från betong kan direkt kopplas till mål 13 i Agenda 2030. Mål 13 verkar bland annat för att Sverige inte skall ha några nettoutsläpp av växthusgaser 2045. Konsekvenser: Om konstruktörer i den mån det är möjligt föreskriver högre vct och lägre exponeringsklasser tyder studien på att de kan minska klimatpåverkan från betong. Att föreskriva högre vct och lägre exponeringsklasser är dock inte alltid möjligt med hänsyn till hållfasthet och omgivning. Studien bidrar till att skapa förståelse för hur stora skillnader gällande klimatpåverkan som kan uppstå beroende på betongkvalitet. Begränsningar: Betong erhåller många egenskaper och en uppsjö av parametrar som påverkar dessa egenskaper. Genom att avgränsa studien och bortse från en del parametrar finns risk för orättvisa resultat. Data som används är publicerad data samt data som betongleverantören vill tillge vilket ger ett bristande verklighetsperspektiv. Majoriteten av betongkvaliteterna som analyserades är av en klimatförbättrad betong och har därmed en lägre klimatpåverkan än vad som vanligen används på plats om inte krav finns. På grund av omgivning och andra förhållanden är det inte alltid möjligt för konstruktören att föreskriva högre vct och lägre exponeringsklass. Studiens fokus ligger på klimatpåverkan vilket begränsar möjligheten att koppla resultatet till flera miljömål. / Purpose: The construction industry will be fundamentally impacted by sustainable development progression. The United Nations have set goals outlined in the 2030 Agenda for sustainable development. To meet this desired progression, these goals must stand in focus for construction professionals and industry stakeholders. Concrete is a composite material made from aggregates, fluids and cement which hardens over time and is widely used in the construction industry. In 2014 it was estimated to account for more than five percent of all anthropogenic carbon dioxide emissions. The purpose of this study is to investigate the climate impact of various concrete mixtures measured as carbon dioxide equivalents and use this to inform whether construction designers can make a difference through the specifications of concrete mixtures. Method: A literature review was conducted to ensure relevance of the study and establish a knowledge base regarding the subject. LCA and a document analysis of EPDs made it possible to compare climate impacts and data could be compiled. Findings: Data from LCA and document analysis indicates that construction designers can reduce the climate impact through their specifications by subscribing higher w/c ratios and lower exposure classes. This enable a bigger amount of the cement to be traded by additives. A literature study indicates that reducing the climate impact of concrete can directly be related to goal 13 in Agenda 2030. In Sweden, goal 13 is to reach no net emissions of greenhouse gases by 2045. Implications: If construction designers specify higher w/c ratio and lower exposure classes, they can reduce the climate impact from concrete. To specify higher w/c ratio and lower exposure class is not always possible depending on the structural requirements. The study adds to an understanding of the climate impact depending on concrete mixtures. Limitations: Concrete obtains many characteristics which is affected by multiple parameters. Limiting the study data and ignoring some parameters increases the risk of deceptive results. Publicly available concrete certifications and data from concrete professionals is combined in this study. Most of the concrete mixtures selected for analysis are climate friendly types and therefore the results would differ if regular concrete was used. Because of structural requirements and other conditions, it is not always possible for the construction designer to specify higher w/c ratio and lower exposure class. This study focuses on climate impacts which limits the possibility to make connections to multiple sustainable development goals. Life Cycle Assessment LCA Environmental Product Declaration EPD Sustainable Development Goals 2030 environmental impact carbon dioxide equivalent concrete quality w/c ratio exposure class cement cement type Life Cycle Assessment LCA Environmental Product Declaration EPD Agenda 2030 klimatpåverkan koldioxidekvivalenter betongkvalitet vct exponeringsklass cement cementtyp Construction Management Byggproduktion
13	Characterization of Fiber Orientation and Weld Line Effects in Reinforced Plastics with Reduced CO2eq Emissions Tolf, Anders, Johannesson, Markus January 2022 (has links) With increasing emphasis and regulations on the environmental footprint in industries, the integration of reduced carbon dioxide equivalent (CO2eq) plastic materials is desirable. Fiber-reinforced plastic materials mechanical properties differ with varying fiber orientations. Similarly, the welding line phenomenon, commonly present in more complex injection molded parts, decreases the mechanical performance. This thesis aims to experimentally investigate tensile behavior on reduced CO2eq reinforced plastics in different fiber orientations and weld line configurations. Ten materials with reduced CO2eq are investigated, the types of materials are as follows: PA6 (Polyamide6), PP (Polypropylene), and PA6/PP blend materials. Both short fiber-reinforced polymers (SFRP) and long fiber-reinforced polymers (LFRP) are investigated. The screening resulted in three selected materials for further investigation: one recycled PA6, one bio-based PA6/PP, and one alternative PP. The further investigation involves tensile testing in the five directions and three weld line configurations with non-standardized geometry specimens punched out from an injection molded plate with controlled fiber orientation. Two types of uniform fiber orientation plates are manufactured for the testing conditions, one with holes for weld line testing and one without for testing of orientation. The evaluated fiber orientations are 0° (fibers parallel to load direction), 22.5°, 45°, 67.5°, and 90° (fibers transverse to load direction). The weld line configuration consists of three consecutive holes with 96.5, 146.5, and 196.5 mm distances from the gating system. Three weld line test specimens are generated from each plate, they are denoted W1, W2, and W3 from their respective distance from the gating system, with W1 being closest to the gate. Optical microscopy of fiber orientation and failure modes for the test specimens are performed to investigate and validate the testing conditions. Varying fiber orientation was found to greatly affect the stress-strain behavior in all four materials investigated. The tensile strength was reduced from longitudinal to transverse fiber orientation, with the most significant reduction near flow direction. High variations were present for the brittle materials supposedly from their weakness to stress concentrations. Strain tended to increase from the lowest at 0° to the maximum at 45°, from which it again decreased to a mid-value at 90° for all materials. The weld line strength reduced significantly for the brittle materials, whereas the ductile materials experienced a much smaller reduction. The three weld line cases failed at similar stresses, while having different stiffness. Fiber-reinforced plastics GFRP Experimental Uniaxial tensile test Uniform fiber orientation plate Tensile strength Fiber orientation Weld line Fracture analysis Microscopy Textile, Rubber and Polymeric Materials Textil-, gummi- och polymermaterial Applied Mechanics Teknisk mekanik Composite Science and Engineering Kompositmaterial och -teknik Other Materials Engineering Annan materialteknik
14	Analysis of a novel thermoelectric generator in the built environment Lozano, Adolfo 05 October 2011 (has links) This study centered on a novel thermoelectric generator (TEG) integrated into the built environment. Designed by Watts Thermoelectric LLC, the TEG is essentially a novel assembly of thermoelectric modules whose required temperature differential is supplied by hot and cold streams of water flowing through the TEG. Per its recommended operating conditions, the TEG nominally generates 83 Watts of electrical power. In its default configuration in the built environment, solar-thermal energy serves as the TEG’s hot stream source and geothermal energy serves as its cold stream source. Two systems-level, thermodynamic analyses were performed, which were based on the TEG’s upcoming characterization testing, scheduled to occur later in 2011 in Detroit, Michigan. The first analysis considered the TEG coupled with a solar collector system. A numerical model of the coupled system was constructed in order to estimate the system’s annual energetic performance. It was determined numerically that over the course of a sample year, the solar collector system could deliver 39.73 megawatt-hours (MWh) of thermal energy to the TEG. The TEG converted that thermal energy into a net of 266.5 kilowatt-hours of electricity in that year. The second analysis focused on the TEG itself during operation with the purpose of providing a preliminary thermodynamic characterization of the TEG. Using experimental data, this analysis found the TEG’s operating efficiency to be 1.72%. Next, the annual emissions that would be avoided by implementing the zero-emission TEG were considered. The emission factor of Michigan’s electric grid, RFCM, was calculated to be 0.830 tons of carbon dioxide-equivalent (CO2e) per MWh, and with the TEG’s annual energy output, it was concluded that 0.221 tons CO2e would be avoided each year with the TEG. It is important to note that the TEG can be linearly scaled up by including additional modules. Thus, these benefits can be multiplied through the incorporation of more TEG units. Finally, the levelized cost of electricity (LCOE) of the TEG integrated into the built environment with the solar-thermal hot source and passive ground-based cold source was considered. The LCOE of the system was estimated to be approximately $8,404/MWh, which is substantially greater than current generation technologies. Note that this calculation was based on one particular configuration with a particular and narrow set of assumptions, and is not intended to be a general conclusion about TEG systems overall. It was concluded that while solar-thermal energy systems can sustain the TEG, they are capital-intensive and therefore not economically suitable for the TEG given the assumptions of this analysis. In the end, because of the large costs associated with the solar-thermal system, waste heat recovery is proposed as a potentially more cost-effective provider of the TEG’s hot stream source. / text Thermoelectric generator TEG Novel thermoelectric generator Thermoelectrics Thermoelectric effect Thermoelectric modules Thermoelectric device Patent application Hot stream source Cold stream source EIA EERE Systems-level analysis Energy balance Control volume analysis Thermodynamic analysis Insolation data Insolation incident on a panel Incident insolation Extraterrestrial insolation NREL Ambient temperature data NOAA Renewable energy sources Energy generation technology Electricity generation technology Thermal energy Coupled system Emissions Greenhouse gas GHG Emissions analysis Zero-emission Emissions avoided Emission factor EF Reliability First Corporation RFC Built environment Integrated into the built environment Solar-thermal energy Solar collector system Photovoltaic thermal PVT panel Thermal storage tank Geothermal energy Geothermal heat pump GHP Ground source heat pump GSHP Numerical analysis Numerical model MATLAB Finite-difference Euler explicit Electric grid Annual energetic performance Annual electricity generation Operating efficiency System efficiency Thermodynamic characterization Economic analysis Levelized cost of energy LCOE Waste heat recovery Carbon dioxide equivalent CO2e Capital costs Installed costs Operating and maintenance costs

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