• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 87
  • 39
  • 10
  • 9
  • 6
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 178
  • 178
  • 62
  • 32
  • 28
  • 17
  • 17
  • 16
  • 16
  • 15
  • 15
  • 15
  • 14
  • 14
  • 14
  • 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.
131

Comparação termodinâmica e ambiental (emissões de CO2) das rotas de produção e utilização de combustíveis veiculares derivados de petróleo e gás natural, biocombustíveis, hidrogênio e eletricidade (veículos elétricos). / Thermodynamics and environmental comparison (CO2 emissions) of production and end use routes of vehicle fuels, derived from petroleum, natural gas, biofuels, hydrogen and electricity (electric vehicles).

Daniel Alexander Flórez-Orrego 21 February 2014 (has links)
O setor de transporte é um exemplo de atividade econômica que depende fundamentalmente das cadeias produtivas do petróleo, gás natural e biocombustíveis para sua operação, além de ser um dos principais consumidores da energia primária do país. Portanto, qualquer melhoria nos processos de produção e uso final dos combustíveis veiculares, repercute favoravelmente tanto na utilização dos recursos energéticos e o desempenho do setor, quanto no impacto ambiental e na economia nacional. Nesse sentido, faz-se necessário o desenvolvimento de uma metodologia que permita avaliar as diferentes rotas de produção e uso final, para determinar as principais fontes de degradação da energia e quantificar o impacto ambiental por meio de uma ferramenta apropriada. Uma valiosa ferramenta é a análise exergética ampliada, a qual provê uma oportunidade de quantificar os requerimentos exergéticos totais e não renováveis e as eficiências globais e, desse modo, perseguir e priorizar o uso daquelas fontes de energia mais favoráveis e amigáveis com o meio ambiente. A exergoeconomia, que visa à distribuição racional dos custos exergéticos entre os diversos produtos de uma mesma planta, usa a quantidade de exergia de cada produto como base para a distribuição da exergia despendida no respectivo processo. Desta forma, neste trabalho se apresenta uma análise comparativa sobre as rotas de produção e uso final dos combustíveis derivados do petróleo e o gás natural (inclusive o hidrogênio produzido da reforma a vapor), etanol, biodiesel, além da análise da geração e distribuição da eletricidade na matriz elétrica brasileira. Propõe-se o uso dos custos exergéticos unitários renováveis e não renováveis e as emissões de CO2 como indicadores para avaliar a intensidade exergética renovável e não renovável, o impacto ambiental e o desempenho termodinâmico no uso final. Este procedimento permite hierarquizar os diferentes processos de conversão de energia na produção e uso final de combustíveis veiculares, a fim de determinar as melhores opções para o setor de transporte. / Transportation sector is an example of economic activity that fundamentally depends on the supply chains of oil, natural gas and biofuels for its operation, as well as being a major consumer of primary energy in the country. Therefore, any improvement that could be achieved in the vehicle fuels production and end use processes, favorably affects both the use of energy resources and industry performance, as well as the environmental impact and the national economy. Accordingly, it is necessary to develop a methodology based on a suitable tool to evaluate the different routes of fuel production and end use, so that the main sources of energy degradation and the environmental impact can be determined and quantified. A valuable tool that serves that purpose is the extended exergy analysis, which provides an opportunity to quantify the total and non-renewable exergy requirements and overall efficiencies, and thereby pursue and prioritize the use of the most environmentally friendly sources of energy. Exergoeconomy, which attempts to rationally distribute the exergy cost among the several products of a single plant, uses the amount of exergy of each product as the basis for the distribution of exergy expended in the respective process. Thus, this work presents a comparative analysis of the production routes and end use of vehicles fuels derived from petroleum and natural gas (including hydrogen produced from methane steam reforming), ethanol, biodiesel, besides of the analysis of generation and distribution of electricity in the Brazilian electricity mix. Moreover, the renewable and non-renewable unit exergy costs and CO2 emissions are proposed as indicators, able to assess the renewable and non-renewable specific exergy consumption, the environmental impact and the thermodynamic performance of transportation sector. This procedure allows to hierarchize the exergy conversion processes in the production and end use of transportation fuels, in order to determine the best options for the transportation sector.
132

Control for transient response of turbocharged engines

Cieslar, Dariusz January 2013 (has links)
The concepts of engine downsizing and down-speeding offer reductions in CO2 emissions from passenger cars. These reductions are achieved by reducing pumping and friction losses at part-load operation. Conventionally, rated torque and power for downsized units are recovered by means of turbocharging. The transient response of such engines is, however, affected by the static and dynamic characteristics of the turbo-machinery. Recent advances in engine simulation and control tools have been employed for the purpose of the research reported in this thesis to identify and verify possible air-path enhancements. A systematic method for evaluating various turbocharger assistance concepts is proposed and discussed in this thesis. To ensure a fair comparison of selected candidate systems, an easily reconfigurable controller providing a close-to-optimal operation, while satisfying physical limits, is formulated. This controller is based on the Model Predictive Control framework and uses a linearised mean value model to optimise the predicted behaviour of the engine. Initially, the controller was applied to a 1D simulation model of a conventional light-duty Diesel engine, for which the desired closed-loop features were verified. This procedure was subsequently applied to various air-path enhancement systems. In this thesis, a turbocharger electric assistance and various concepts based on compressed gas injection were considered. The capability of these systems to improve engine response during third gear tip-in manoeuvre was quantified. This investigation was also complemented with a parametric study of how effectively each of the considered methods used its available resources. As a result, injecting compressed gas into the exhaust manifold was identified as an effective method, which to date has attracted limited attention from engine research community. The effectiveness of the exhaust manifold assistance was experimentally verified on a light-duty Diesel engine. The sensitivity of the improvements to compressed gas supply parameters was also investigated. This led to the development of the BREES system: a low component count, compressed gas based system for reducing turbo-lag. It was shown that during braking manoeuvres a tank can be charged to the level sufficient for a subsequent boost assistance event. Such a functionality was implemented with a very limited set of additional components and only minor changes to the standard engine control.
133

Druhá generace biopaliv v reálném světě / The second generation of biofuels in the real world

Skalický, Michal January 2009 (has links)
The diploma thesis deals with the problematics of biofuels as a renewable source of energy in transportation, which has recently gotten under social spotlight. The theoretical part is focused on an explanation of basic terminology, historical development and especially reasons for the need to replace current fosil fuels with respect to an increasing volume of CO2 and shortening oil reserves. The practical part compares characteristics, use, pros and cons of the biofuels of the first and second generation and tries to estimate benefits of the biofuels of the second generation in both economic and environmental area.
134

Manejo da palha, adubação nitrogenada potássica e uso de inoculante em soca de cana-de-açúcar / Management of harvest residue, nitrogen, potassium and use of inoculants in ratoon sugarcane

Vale, Diego Wyllyam do 21 February 2013 (has links)
A colheita de cana-de-açúcar, sem despalha a fogo, vem crescendo no Brasil. Nesse sistema de cultivo, existem muitas dúvidas em relação ao manejo da palha, e das quantidades de nitrogênio e potássio a serem utilizadas. Objetivou-se avaliar o manejo da palha, adubação nitrogenada, potássica e uso do inoculante em área comercial de cana-de-açúcar. Para isso, instalou-se experimento na região de Piracicaba - SP, num Latossolo Vermelho Amarelo Distrófico, cultivado com a variedade de cana-de-açúcar CTC 9, em delineamento de blocos casualizados em esquema fatorial incompleto 3x6x4, totalizando 153 parcelas, sendo três manejos da palha-MP (distribuição da palha da cana em toda área-MPT, retirada da palha apenas nas linhas da cana-de-açúcar-MPRL e enleiramento da palha a cada duas linhas-MP2:1), seis doses de N (aplicação de 0, 60, 120 e 180 kg ha-1 de N, aplicação na linha da cana de solução contendo cinco espécies de bactérias fixadoras de nitrogênio na ausência de adubação nitrogenada e aplicação na linha da cana de solução contendo cinco espécies de bactérias fixadoras de nitrogênio mais 30 kg ha-1 de N mineral), quatro doses de K (0, 50, 100 e 150 kg de K2O ha-1) e três repetições. As variáveis analisadas ao longo das duas socas foram: análises químicas do solo, emissão de CO2, diagnose foliar, avaliações biológicas e tecnológicas e produção de colmos da cana-de-açúcar. A aplicação de nitrogênio e potássio afetou a fertilidade do solo, teor foliar de N, açúcar teórico recuperável e crescimento da cana-de-açúcar. A aplicação de 80 kg ha-1 de K2O é suficiente para apresentar alta produtividade da primeira (87 t ha-1) e da segunda soca de cana-deaçúcar (141 t ha-1) e não houve resposta a aplicação de nitrogênio mineral. A aplicação de inoculante não aumentou a produtividade da cana-de-açúcar. O MPRL se mostrou como o mais promissor em relação ao crescimento e produtividade da cana-de-açúcar. O MPRL apresentou maior emissão de carbono se comparado ao MP2:1 na 2a soca. Na 1ª soca, no MPT, MPRL e MP2:1, a emissão de CO2 foi de 1,7; 2,0 e 1,7 ?mol m-2 s-1, a temperatura foi de 21,7; 21,7; 21,2 ºC e a umidade foi de 11,1; 6,6 e 9,5%, respectivamente. Na 2ª soca, no MPT, MPRL e MP2:1, o CO2 foi de 1,8; 2,1 e 1,6 ?mol m-2 s-1, a temperatura foi de 21,4; 22,9; 22,4 ºC e a umidade foi de 16,9; 12,3 e 11,5%, respectivamente. A emissão de CO2 aumentou com o crescimento das plantas de cana-de-açúcar e oscilou de 6 a 12,4 ?mol m-2. / The harvesting of sugarcane, straw removal without fire, is growing in Brazil. In this culture system, there are many questions about the management of residue, and the amounts of nitrogen and potassium to be used. This study aimed to evaluate the straw management sugarcane, nitrogen, potassium and use of inoculants in commercial sugarcane. For this experiment was installed in Piracicaba - SP, in the Oxissol cultivated with the variety of sugarcane CTC 9, in a randomized block design in a incomplete factorial 3x6x4, totaling 153 plots, three management of stubble-MP (distribution of sugarcane trash in every area-MPT, removal of straw only rows of sugarcane MPRL and windrowing straw every two lines-MP2:1) six doses of N (application of 0, 60, 120 and 180 kg ha-1 of N, applied in line with the cane solution containing five species of nitrogen-fixing bacteria in the absence of nitrogen fertilizer application on line and cane solution containing five species of nitrogen-fixing bacteria plus 30 kg ha-1 of mineral N), four doses of K (0, 50 , 100 and 150 kg ha-1 of K2O) and three replications. The variables analyzed along the two years were: soil chemical analysis, CO2 emission, foliar diagnosis, biological and technological evaluations and straw yield of sugarcane. The application of nitrogen and potassium affect soil fertility, leaf N content, theoretical recoverable sugar and growth of sugarcane. The application of 80 kg ha-1 of K2O is sufficient to present the first high productivity (87 t ha-1) and second ratoon sugarcane (141 t ha-1) and there was no response from the application nitrogen mineral. The inoculant application did not increase productivity of sugarcane. The MPRL proved as the most promising in relation to growth and productivity of sugarcane. The MPRL had lower moisture and higher carbon footprint compared to MPT and MP2:1. In the 1st ratoon, the MPT, MPRL and MP2:1, the emission of CO2 was 1.7, 2.0 and 1.7 ?mol m-2 s-1, the temperature was 21.7, 21.7; 21.2 ºC and humidity was 11.1, 6.6 and 9.5%, respectively. In the 2nd ratoon in MPT, MPRL and MP2:1 first, the CO2 was 1.8, 2.1 and 1.6 ?mol m-2 s-1, the temperature was 21.4, 22.9; 22, 4 ºC and the humidity was 16.9, 12.3 and 11.5%, respectively. The emission of CO2 increased with the growth of plants sugarcane and oscillated 6 to 12.4 ?mol m-2 s-1.
135

Elektromobilität im Saarland: Ein Ideen- und Umsetzungskonzept

Hinkeldein, Daniel, Hunsicker, Frank, Knie, Andreas 14 January 2020 (has links)
Der Verkehrssektor ist einer der Hauptverursacher von CO2-Emissionen. Der motorisierte Individualverkehr (MIV) zeichnet für den höchsten Anteil daran verantwortlich. Die Nutzung eines Autos ist jedoch für viele unverzichtbar. Die Kosten für den eigenen Pkw steigen seit Jahren. Kostenfreie und verfügbare Parkplätze sind knapp und der Berufsverkehr fließt oft nur stockend. Angebote des öffentlichen Verkehrs können nicht in jedem Fall die alltäglichen Mobilitätsbedürfnisse befriedigen. Die Elektromobilität wird von Industrie, Regierungen und auch potenziellen Nutzern als chancenreiche Alternative gesehen, um fossile Brennstoffe im Verkehrssektor langfristig abzulösen. Allerdings zeigt sich mehr und mehr, dass deren kurzfristige, flächendeckende Einführung nur mit einer Integration in den öffentlichen Verkehr (ÖV) gelingen kann. Niedrige Reichweiten, lange Ladedauern sowie hohe Anschaffungskosten der Fahrzeuge erfordern derart neue Mobilitätskonzepte. Vor diesem Hintergrund gewinnen Miet- und Sharing- Modelle v.a. in größeren Städten an Bedeutung. Sie sichern automobile Mobilität, ohne dass Nutzer dazu einen eigenen Pkw anschaffen oder auch dann Kosten tragen müssen, wenn sie ihn gar nicht nutzen. Deshalb soll der Betrieb einer elektromobilen Fahrzeugflotte zur spontanen Nutzung im Saarland aufgenommen werden. Verschiedene Formen des Flottenbetriebs (z.B. standortgebundenes Carsharing, Spontanmiete, Pendlerflotte) sollen auf ihre Praxistauglichkeit getestet werden. Zielsetzung des saarländischen Ministeriums für Umwelt, Energie und Verkehr ist die technische und wirtschaftliche Einbindung von Elektrofahrzeugflotten in den ÖV unter Einsatz moderner Informations- und Kommunikationstechnologie. Dabei geht es einerseits um die Schaffung einer effizienten Energie- und Elektromobilitätsinfrastruktur unter vollständiger Nutzung regionaler regenerativer Energien, andererseits um Organisation und Betrieb mittels marktwirtschaftlicher Steuerungsmechanismen. Die Integrationsansätze orientieren sich konsequent an privaten und gewerblichen Nutzerinteressen und den Anforderungen der Stadtverträglichkeit. Damit soll die Voraussetzung zur Realisierung eines innovativen und leistungsstarken, effizient ergänzten öffentlichen Verkehrssystems geschaffen werden. / Within the context of climate change, transport can be a dilemma. On the one hand, the transport sector is one of the main sources of CO2 emissions, with motorised private transport being responsible for the largest share. On the other hand, to many users the car as a mode of transport is irreplaceable. Using cars has become more and more expensive in recent years, while slow rush hour traffic and the spatial expansion of priced parking have aggravated the situation for car drivers rather than tied them to more sustainable transport modes. Inflexible structures of classic public transport have not been able to accommodate certain transport needs. Therefore, industry, government and potential users alike rest their hopes for a sustainable transport sector on electric mobility (electric cars, motor-cycles, scooters and bikes). At the moment, however, it is becoming increasingly clear that a wide-spread use of electric cars can only succeed in combination with public transport. Low ranges, long loading times and high prices of electric cars need a new kind of mobility. This explains why rental and sharing schemes are gaining popularity, particularly in larger cities: They preserve automobile mobility while avoiding the costs of buying and keeping a car. That is why the Saarland, one of the westernmost German Länder, will integrate a number of electric cars into its public transport system. Different kinds of integration (e.g. carsharing stations, spontaneous use and use for commuters) will be tested as to their usability in everyday practice. Modern information and communications technologies will assist with fully integrating electric vehicles into public transport, i.e. technically as well as economically. The project is headed by the Saarlandian Ministry for the Environment, Energy and Transport, whose aims are twofold: First, to create an efficient infrastructure for electric vehicles based on regional renewable energies. And second, to integrate market mechanisms into the project. Therefore, the rental system will be based on efficiency, customer demand and criteria for a sustainable integration of the vehicles into cities. This will pave the way for an innovative, convenient, efficient and multi-modal public transport system.
136

Advanced Modelling and Energy Efficiency Prediction for Road Vehicles

Nordström, Erik January 2020 (has links)
This thesis presents a first real world case-study of road transport operations that use the COVER format, in which the driver and the vehicle are regarded as separate entities. This format enables a complex representation of the transport operation that potentially better describe reality compared to the conventional representation used in today’s certification tools. The representation of operations treated in this thesis is called Operating Cycles and has been used to fully describe three representative transport missions from a case-study truck. Stochastically generated operating cycles have been used to create a large data set and thus prevent overfitting of specific cycles. The Operating Cycle-representation allowed for fair comparison between vehicle designs and ultimately manifested a vehicle composition that reduced the fuel consumption by nearly 10% for the same kind of transport operations.
137

Analysis on copper, lead and tin removal in steel scrap sorting : Technologies involved, environmental considerations and economic aspects

Cavaliere, Giada January 2023 (has links)
With the urgency of cutting down CO2 emissions to reach climate neutrality by 2050, decarbonization of the steel industry is on the European Commission's agenda. Steelmaking accounts for 10 % of anthropogenic CO2 emissions and it is one of the most challenging sectors to decarbonize. A solution that could support this progressive shift is to put more trust into the electric arc furnace (EAF) process, which relies on steel scrap as the main feedstock, but currently it is only responsible for 40% of the EU steelmaking. The almost remaining percentage is taken by the blast furnace route. Multiple European blast furnaces are currently closing due to low demands, high competition on imports and extremely high energy prices for production due to the Russian invasion of Ukraine situation. This particular moment could the proper time for increasing the employment of the EAF process. Moreover, the latter could help to improve resource efficiency and circularity of steel scrap thanks to the usage of higher shares of it, creating a “closed loop” for the steel industry. The reality of using more steel scrap is not actually very far from where we are, however, this will not be easy to reach. In fact, to ensure that the steel scrap is recycled "infinite" times it must contain very low quantities of impurities, such as copper (Cu}, tin (Sn) and lead (Pb}. Most of the times, this does not happen. Thus scrap is diluted with virgin iron to disperse those unwanted elements. This practice leads to a gradual decline of steel scrap quality, which is not in accordance with what it has just stated above. To worsen this situation even more, forecast is predicting increasing quantities of Cu that will accumulate into the steel scrap streams, due to the expected rising electric vehicles production. The aim of the following thesis work is to set a model to design a potential sorting solution to provide a higher copper (the most annoying cause of concern) removal rate in steel scrap, considering the economic and environmental implications of its implementation in the industry. Nonetheless, the presence of even lead and tin will also be taken into account. Results showcases that it is possible to get better impurities removal compared to what it has been done in many EU steel scrapyards, with ballistic separation as an additional refining separation step. Moreover, it is also an economically convenient and easy implementable solution that would assure higher quality steel scrap downstream of the process and that would also bring substantial economic and environmental benefits. / Med det brådskande att minska CO2-utsläppen för att nå klimatneutralitet till 2050, står avkarbonisering av stålindustrin på EU-kommissionens agenda. Ståltillverkning står för 10 % av antropogena koldioxidutsläpp och det är en av de mest utmanande sektorerna att ta bort koldioxid. En lösning som skulle kunna stödja denna progressiva förändring är att sätta mer förtroende till den elektriska ljusbågsugnsprocessen (EAF), som är beroende av stålskrot som huvudråvara, men för närvarande är den bara ansvarig för 40 % av ståltillverkningen i EU. Den nästan återstående andelen tas av masugnsvägen. Flera europeiska masugnar stängs för närvarande på grund av låga krav, hög konkurrens på import och extremt höga energipriser för produktion på grund av den ryska invasionen av Ukraina. Just detta ögonblickkan vara fördelaktigt för att öka sysselsättningen av EAF-processen. Dessutom skulle det senare kunna bidra till att förbättra resurseffektiviteten och cirkulariteten för stålskrot tack vare användningen av högre andelar av det, vilket skapar en "sluten slinga" för stålindustrin. Verkligheten med att använda mer stålskrot är faktiskt inte särskilt långt ifrån där vi är, men detta kommer inte att vara lätt att nå. Faktum är att för att säkerställa att stålskrotet återvinns "oändliga" gånger måste det innehålla mycket små mängder föroreningar, såsom koppar (Cu), tenn (Sn) och bly (Pb). Oftast händer detta inte. Således späds skrot med jungfruligt järn för att skingra dessa oönskade element. Denna praxis leder till en gradvis försämring av stålskrotskvaliteten, vilket inte är i enlighet med vad den nyss har angett ovan. För att förvärra denna situation ännu mer, förutspår prognosen ökande mängder Cu som kommer att ackumuleras i stålskrotströmmarna, på grund av den förväntade ökande produktionen av elfordon. Syftet med följande examensarbete är att sätta en modell för att designa en potentiell sorteringslösning för att ge en högre kopparavskiljningshastighet (den mest irriterande orsaken till oro) i stålskrot, med tanke på de ekonomiska och miljömässiga konsekvenserna av dess implementering i industrin. Icke desto mindre kommer förekomsten av jämnt bly och tenn också att beaktas. Resultaten visar att det är möjligt att få bättre bortförsel av föroreningar jämfört med vad man har gjort på många stålskrotvarv i EU, med ballistisk separering som ett extra raffineringssteg. Dessutom är det också en ekonomiskt bekväm och lätt implementerbar lösning som skulle säkerställa högre kvalitet stålskrot nedströms om processen och som också skulle ge betydande ekonomiska och miljömässiga fördelar.
138

Obstacles and Opportunities forReusing Material in theConstruction and Real Estate Industry : A study towards an upscaled reuse implementation to achieve net zero emission at Akademiska Hus / Hinder och Möjligheter för att Implementera Återbruk i Byggbranschen : En studie med syftet att öka återbruksimplementeringen för att uppnå nettonollutsläpp på Akademiska Hus

Chaba, Kristina, Mridha, Natasha January 2022 (has links)
The construction- and real estate industry can be held accountable for major pollution and is responsible for 20% of the total emissions of greenhouse gasses in Sweden. To reduce their emissions and contribute to a sustainable future, actors in the industry work effectively to transition from a linear economy to a circular one. This includes the circularity of construction materials used in buildings and facilities. Reuse of construction materials is becoming more common and is discussed throughout the industry as an effective way of decreasing waste and CO2 emissions from the industry. However, the industry has been facing difficulties implementing new and effective ways to reuse construction materials. In this study, obstacles to implementing reuse as well as development opportunities have been evaluated. The study aims to identify the main obstacles for an upscaled reuse, their causes and effects as well as give suggestions on development opportunities to facilitate the reuse of construction materials. Primarily, a literature review was conducted to create an understanding of reuse today and to identify the main obstacles and development opportunities as well as creating a basis for the qualitative research. Thereafter, empirical data was collected through semi-structured interviews with different actors and specialists within reuse. Finally, the collected data from the literature review and the interviews was divided into key areas and compared, resulting in a list of main obstacles and suggestions for development opportunities for each key area. The ten barriers that were found are (1) Habits and Attitudes, (2) Knowledge and Lack of a Holistic Approach, (3) Tools and Systems, (4) Cost, Revenue and Time, (5) Supply and Demand, (6) Logistics, (7) Lack of Sustainability Procurements and Incentives, (8) Laws and Regulations, (9) Quality Assurance and (10) Technical Obstacles. The results reveal that many of the obstacles and development opportunities identified in the literature study align with the respondents’ answers in the qualitative study. Furthermore, a reuse potential is identified, but it requires internal as well as external adjustments within the construction and real estate industry. Examples of these external adjustments is increased flexibility in the laws and regulations set by external authorities and putting more demands on contractors and subcontractors to adapt their work procedures according to circularity. Recommendations gathered for construction and real estate companies are to set general guidelines and goals for reuse within the organization. Furthermore, actors within the industry should work on spreading knowledge to initiate circular thoughts from the start of a project. They should also create awareness of the value of reusing and disseminate knowledge about reuse within the organization, to partners in the industry and to the end customers. To facilitate future reuse implementation, companies should work on designing for disassembly (DfD) and use more standardized and general measures when designing. Companies should also work on digitalization to create tools and systems that streamline their work and use BIM to predict future supply assets and store information about construction materials. / Bygg- och fastighetsbranschen ansvarar för en stor andel föroreningar och står idag för 20% av det totala utsläppet av växthusgaser i Sverige. För att minska på sitt utsläpp och bidra till en hållbar framtid arbetar aktörer i branschen effektivt med övergå från en linjär ekonomi till en cirkulär. Detta inkluderar cirkularitet av bygg- och konstruktionsmaterial som används i byggnader och anläggningar. Återbruk av byggmaterial blir allt vanligare och diskuteras ur hela branschen som ett effektivt sätt att minska avfall och CO2-utsläpp från industrin. Branschen har dock upplevt svårigheter att implementera nya och effektiva metoder för återbruk av byggmaterial. I denna studie har såväl hinder som utvecklingsmöjligheter för återbruk av byggmaterial utvärderats. Studien syftar till att identifiera huvudsakliga hinder, deras orsaker och effekter samt ge förslag på utvecklingsmöjligheter för att underlätta återbruk av byggmaterial. I första hand gjordes en litteraturgenomgång för att skapa förståelse för återbruk idag, identifiera de främsta hindren och utvecklings möjligheterna samt skapa en grund för den kvalitativa studien. Därefter samlades empiri in genom semistrukturerade intervjuer med olika aktörer och specialister inom återbruk. Slutligen delades den insamlade datan från litteraturgenomgången liksom intervjuerna in i nyckelområden för att jämföras. Detta resulterade i en lista bestående av huvudsakliga hinder samt förslag på utvecklingsmöjligheter för respektive nyckelområde. De tio barriärerna som hittades är (1) Vanor och Attityder, (2) Brist på Kunskap & ett Gemensamt synsätt , (3) Verktyg & System, (4) Kostnad, Intäkter och Tid, (5) Utbud & Efterfrågan, (6) Logistik, (7) Brist på cirkulära upphandlingar, (8) Lagar och Regler, (9) Kvalitetssäkring och (10) Tekniska Hinder. Resultatet visar att många hinder och utvecklingsmöjligheter som identifierats i litteratstudien överensstämmer med respondenternas svar från den kvalitativa studien. Vidare påvisar resultatet att en återbrukspotential existerar, men detta kräver interna samt externa anpassningar inom byggbranschen. Exempel på externa anpassningar är ökad flexibilitet i lagar och regler som ställs av externa myndigheter och en förhöjd kravsättning på entreprenörer för en anpassning till cirkulärt arbete. Rekommendationer för bygg- och fastighetsbranschen är att sätta allmänna riktlinjer och mål för återanvändning inom organisationen. Vidare bör aktörer inom branschen arbeta med kunskapsspridning för att öka det cirkulära tänkandet redan under projekteringsfasen. De bör även arbeta för att skapa medvetenhet om värdet av att återbruka och sprida kunskap om återbruk inom organisationen, till samarbetspartners i branschen och slutkunder. För att underlätta framtida återbruksimplementering bör företag arbeta med DfD (Design for Disassembly) och använda standardiserade och generella mått vid projektering. Företag bör också arbeta med digitalisering och skapa verktyg och system som effektiviserar arbetet. Likaså är BIM ett hjälpmedel för att förutsäga framtida leveranstillgångar och lagrar information om byggmaterial.
139

FEASIBILITY ANALYSIS OF THE DRIVE TRAIN ELECTRIFICATION FOR A RESCUE BOAT

Andruetto, Claudia January 2019 (has links)
Progressing constraints on green house gas emissions lead to a sustainability trend,which greatly a↵ects the transport sector. Nowadays, companies show increasing interest indeveloping sustainable solutions.This thesis has been started thanks to a project given by Sj¨or¨addningss¨allskapet, themost relevant association that performs sea rescue operations in Swedish waters.Sj¨or¨addningss¨allskapet would like to explore the possibility of making their rescue boat fleetentirely carbon-free, hence more sustainable.What may provide a suitable solution is an electric drive train with hybrid energy storage,composed by a battery pack and a fuel cell stack. The research question is whether it wouldbe feasible to combine fuel cell stacks and battery packs to provide power to a fast smallboat.From a sketch of a rescue boat, the drive train design for such boat is studied in itsintegrity, from the water jet pump to the battery and fuel cell systems.The required power has been calculated empirically, using data from online tests on waterjet boats. Di↵erent tests have been considered, resulting in a mean power curve and a meanconsumption curve and allowing comparison between the hybrid electric drive train withan internal combustion engine drive train.Three profiles of speed, power and consumption have been assumed for the calculation ofthe required energy and hence rate the energy storage system. A design has been proposedin terms of fuel cell capacity and battery capacity.The propulsion unit, composed by the electric machine and water jet, has been studied,focusing on di↵erent electric drive technologies. Few conclusions on both the weight andsustainability requirements are discussed.A sustainability analysis is carried out in terms of CO2 emissions, through a life cycleassessment accounting for the environmental impact of the system during the whole lifecycle, from cradle to grave. / Ökande begränsningar för utsläpp av växthusgaser leder till en hållbarhetsutveckling, vilket påverkar transportsektorn kraftigt. Nuförtiden visar företag ett ökande intresse för att utveckla hållbara lösningar.‌Denna avhandling har startats tack vare ett projekt som ges av Sjöräddningssällskapet, den viktigaste föreningen som utför havsräddningsinsatser i svenska vatten.Sjöräddningssällskapet vill undersöka möjligheten att göra deras räddningsbåtflotta helt emissionfri, och därmed mer hållbar.Det som kan ge en lämplig lösning är ett elektriskt drivsystem med hybrid energilagring, sammansatt av ett batteripaket och en bränslecell-stapel. Forskningsfrågan är om det skulle vara möjligt att kombinera bränslecellstaplar och batteripaket för att driva en snabb liten båt.Från en skiss av en räddningsbåt studeras designen för en sådan båt i dess integritet, från vattenstrålpumpen till batteri och bränslecellsystem.Den erforderliga kraften har beräknats empiriskt med hjälp av data från onlinetest av vattenstrålbåtar. Olika tester har beaktats, vilket resulterar i en genomsnittlig e↵ektkurva och en genomsnittlig förbrukningskurva och möjliggör en jämförelse mellan det hybridelektriska drivsystemet med ett förbränningsmotordrivsystem.Tre profiler av hastighet, e↵ekt och förbrukning har antagits för beräkning av den erforderliga energin och därmed för energilagringssystemet. En design har föreslagits vad gäller bränslecellkapacitet och batterikapacitet.Framdrivningsenheten, sammansatt av den elektriska maskinen och vattenstrålen, har studerats med fokus på olika elektriska drivtekniker. Några slutsatser om både vikten och hållbarhetskraven diskuteras.En hållbarhetsanalys utförs med avseende på koldioxidutsläpp genom en livscykelbedömningsom redovisar systemets miljöpåverkan under hela livscykeln, från vagga till grav.
140

Carbon emission allocation of Ro-Pax ferry transport and the application for ferry companies / Fördelning av koldioxidutsläpp för Ro-Pax-färjetransporter och tillämpning för färjerederier

Xu, Qiutong January 2023 (has links)
The EU has set up the target of cutting GHG emissions by at least 55% by 2030 and becoming climateneutral by 2050. Accordingly, the IMO has launched initiatives to reduce CO2 emissions per transportwork by at least 40% by 2030, however the CO2 emissions generated from the ferry operations arecontinuously increasing. Although the research focussing on carbon emission reduction technology isgrowing as well, the emission allocation, the prerequisite for emission measuring and reporting as wellas evaluating emission reduction effects, is still an area that hasn’t been explored in depth especiallyfor the ferry industry. This study explores and evaluates the way of allocating CO2 emissions betweenthe passenger and freight for Ro-Pax ferry. Firstly, the emission allocation methods from differentsectors and modes of transportation have been reviewed, revised and developed into the allocationmethods suitable for Ro-Pax transport. Afterwards, the case study of ferry companies with part or all ofthe routes in the Baltic Sea has been carried out to compare and evaluate the performance of differentemission allocation methods. The study suggests that the weight allocation method has the tendencyto assign large amounts of carbon emissions to the freight, while the passenger accounts for moreemissions when applying area, volume and alternative production methods. Furthermore, the practiceshows that foot passengers could contribute to CO2 emission reduction by choosing ferry travel insteadof the airplane, and the car passengers could generate less CO2 emission by sharing the car withothers. The study provides valuable insights for decision makers, standard setters and ferry companies,and could be the solid groundwork for further research on carbon emission allocation for other transportmodes or deeper exploration of a specific allocation method. / EU har satt upp målet att begränsa ökningen av växthusgasutsläpp till 2030 och IMO har lanseratinitiativ för att leda minskningen av växthusgasutsläpp, men de växthusgasutsläpp som genereras frånfärjetrafiken ökar kontinuerligt. Även om forskningen som fokuserar på teknik och åtgärder för attminska utsläppen av växthusgaser också växer, är utsläppsallokering, grunden för utsläppsminskning,fortfarande ett område som inte har utforskats på djupet, särskilt inte för färjeindustrin. I denna studieundersöks en lämplig metod för att fördela växthusgasutsläpp mellan passagerare och gods för Ro-Pax-färjor. För det första har utsläppsallokeringsmetoder från olika sektorer och transportsätt granskats,reviderats och utvecklats till allokeringsmetoder som är lämpliga för Ro-Pax-transporter. Därefter haren fallstudie av färjerederier med en del av eller alla rutter i Östersjön genomförts för att jämföra ochutvärdera prestandan hos olika utsläppsallokeringsmetoder. Studien visar att viktfördelningsmetodenhar en tendens att tilldela stora mängder koldioxidutsläpp till frakten, medan passagerarna står för merutsläpp när man tillämpar yta, volym och alternativa produktionsmetoder. Dessutom visar praxis attfotpassagerare kan bidra till minskade växthusgasutsläpp genom att välja färja istället för flygplan, ochbilpassagerare kan generera mindre växthusgasutsläpp genom att dela bilen med andra. Studien gervärdefulla insikter för beslutsfattare, standardsättare och färjerederier, och kan utgöra en solid grundför vidare forskning om fördelning av växthusgasutsläpp för andra transportsätt eller djupare utforskningav en specifik fördelningsmetod.

Page generated in 0.0813 seconds