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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

A GIS-Based Simulation Method for Regional Food Potential and Demand

Bao, Keyu, Padsala, Rushikesh, Coors, Volker, Thrän, Daniela, Schröter, Bastian 05 May 2023 (has links)
A quantitative assessment of food-water-energy interactions is important to assess pathways and scenarios towards a holistically sustainable regional development. While a range of tools and methods exist that assess energetic demands and potentials on a regional scale, the same is not true for assessments of regional food demand and potential. This work introduces a new food simulation workflow to address local food potential and demand at the regional level, by extending an existing regional energy-water simulation platform. The goal of this work is to develop a GIS-based bottom-up approach to simulate regional food demand that can be linked to similarly GIS-based workflows assessing regional water demands and energetic demands and potentials. This allows us to study food-water-energy issues on a local scale. For this, a CityGML land use data model is extended with a feed and animal potential raster map as well as a soil type map to serve as the main inputs. The workflow simulates: (1) the vegetal and animal product food potentials by taking climate, crop type, soil type, organic farming, and food waste parameters into account; (2) the food demand of vegetal and animal products influenced by population change, body weight, age, human development index, and other indicators. The method is tested and validated in three German counties with various land use coverages. The results show that restricting land used exclusively for energy crop production is the most effective way to increase annual food production potential. Climate change by 2050 is expected to result in annual biomass yield changes between −4% and 2% depending on the region. The amount of animal product consumption is expected to rise by 16% by 2050, while 4% fewer vegetal products are excepted to be consumed.
32

Energiprisstrukturens inverkan på val av energieffektiviseringsåtgärder : En analys av trender inom el- och fjärrvärmeprissättning och dess inverkan på effektiviseringsåtgärder i bostadsbeståndet

Wallenbert, Henrik January 2017 (has links)
The purpose of this examination is to see how energy efficiency measures affect peak loads in multifamily buildings. In addition, how much of an energy share warm water has in peak loads. The Swedish building sector represents 40 % of all energy used. The thesis was restricted to multifamily buildings, which is dominated by district heating. The most common energy measures to save peak cost and reduce peak loads that are focus in this thesis work, e.g. changing windows, isolate walls and attics but also lowering indoor temperature. It was assumed in the thesis that the cost of peak loads will increase in the future and therefore the choice of energy efficiency measures is important. The calculations to determine the effectiveness of the energy measures where done by using hourly temperature data from the year 2014 in combination with, known investment costs for each energy measure. The only measures that went with profit over a 40-year period was the attics isolation and lower indoor temperature. The highest peak load savings in heating was the change of windows and wall isolation, but the investment cost was too high to gain a profit. The conclusion is that the best energy efficiency measures are attic isolation and lower indoor temperature because of its low investment cost and quick payback time, but also effective at lowering peak load by reducing the temperature difference between outdoor and indoor temperature in multifamily buildings. The analysis of warm water energy's share of the peak loads varied much between the 15 given multifamily buildings, where a base load and a peak load where compared. The result was between 10-50 % were the difference between the buildings warm water energy share off the peak loads. It where concluded that a standard value of 20 % would give much inaccuracy in determining the warm water share. It is therefore, suggested to use this method to determine the warm water share of the hourly peak load. / I detta arbete har syftet varit att hitta de vanligaste energieffektiviseringsåtgärderna som görs idag i det svenska bostadsbeståndet. Energieffektiviseringsåtgärderna påverkar effekttoppar i flerbostadshus och har undersökts. Om det antas att energiprisstrukturen går mot en mer effektbaserad taxa kan åtgärderna få större påverkan på energipriset i framtiden. I arbetet har varmvattnets andel av timeffekttoppar undersökts, med stöd av energianvändningsdata från 15 anonymiserade flerbostadshus med fjärrvärme. Energianvändningen i bostadsbeståndet står för ca 40 % av Sveriges energianvändning. Det ställs då krav på de lågenergihus som byggs idag och vid renovering av hus att möta Sveriges som såväl EU 2020 målet att minska energianvändningen i bostäder genom att implementera energieffektiviseringsåtgärder. De vanligaste energieffektiviseringsåtgärderna i flerbostadshus har varit isolering av väggar och vind, installation av energiglas och frånluftssystem med värmeåtervinning. En sänkt inomhus temperatur har även medtagits. För fastighetsägare av flerbostadshus, där energianvändning för uppvärmning och varmvatten domineras av fjärrvärme är prisutvecklingen viktig. Om i framtiden ett antagande görs att el och fjärrvärmepriset övergår från en energibaserad taxa kr/kWh till en mer effektbaserad taxa kr/kW där kunden betalar för de högsta effekttopparna under ett år. I denna studie redovisas det när effekttoppar uppstår och vilka energieffektiviseringsåtgärder som påverkar effekttopparna i flerbostadshus. De högsta effekttopparna uppstår oftast under vinterårstiden då uppvärmningsbehovet är störst. I ett framtaget typbostadshus där de valda energiåtgärderna beräknades, det visade sig att energiglas minskar effektbehovet och effektpriset mest, därefter väggisolering med mineralull. Emellertid ger energiglas och väggisolerings åtgärderna ger förluster i lönsamhetsberäkningen. Det skiljer sig från tilläggsisolering med mineralull av vinden och sänkt inomhus temperatur som har en investerings vinst över en 40 års period. I beräkningarna användes temperaturdata från år 2012 både på typhuset innan och efter implementerad åtgärd.En viktig parameter vid minskning av uppvärmningsbehovet är U-värdet. Tilläggsisolering av vind samt sänkt temperatur är de åtgärder som rekommenderas då båda påverkar effektbehovet och ger en lönsam investering. Åtgärd vid fönster och väggar minskar dock uppvärmningsbehovet mest men ger en olönsam ekonomisk investering. Varmvattenandelen av den högsta timeffekttoppen över året togs fram genom att jämföra baslasten och effekttoppen under dagen då effektbehovet är som högst. Resultatet visade att varmvattenandelen av effekttoppen tycks variera mellan ca 10- 50 %. Varmvattenandelen av effekttoppen varierar stort och därför föreslås användningen av metoden i detta examensarbete istället för ett schablonvärde på 20 % vid undersökning av varmvattenandelen av timeffekttoppen.
33

Environmental Sustainability of Wastewater Treatment Plants Integrated with Resource Recovery: The Impact of Context and Scale

Cornejo, Pablo K. 16 September 2015 (has links)
There is an urgent need for wastewater treatment plants (WWTPs) to adapt to a rise in water and energy demands, prolonged periods of drought, climate variability, and resource scarcity. As population increases, minimizing the carbon and energy footprints of wastewater treatment, while properly managing nutrients is crucial to improving the sustainability WWTPs. Integrated resource recovery can mitigate the environmental impact of wastewater treatment systems; however, the mitigation potential depends on various factors such as treatment technology, resource recovery strategy, and system size. Amidst these challenges, this research seeks to investigate the environmental sustainability of wastewater treatment plants (WWTPs) integrating resource recovery (e.g., water reuse, energy recovery and nutrient recycling) in different contexts (developing versus developed world) and at different scales (household, community, and city). The over-arching hypothesis guiding this research is that: Context and scale impact the environmental sustainability of WWTPs integrated with resource recovery. Three major research tasks were designed to contribute to a greater understanding of the environmental sustainability of resource recovery integrated with wastewater treatment systems. They include a framework development task (Chapter 2), scale assessment task (Chapter 3), and context assessment task (Chapter 4). The framework development task includes a critical review of literature and models used to design a framework to assess the environmental sustainability of wastewater treatment and integrated resource recovery strategies. Most studies used life cycle assessment (LCA) to assess these systems. LCA is a quantitative tool, which estimates the environmental impact of a system over its lifetime. Based on this review, a comprehensive system boundary was selected to assess the life cycle impacts of collection, treatment, and distribution over the construction and operation and maintenance life stages. Additionally, resource recovery offsets associated with water reuse, energy recovery, and nutrient recycling are considered. The framework’s life cycle inventory includes material production and delivery, equipment operation, energy production, sludge disposal, direct greenhouse gas (GHG) emissions, and nutrients discharged to the environment. Process-based LCA is used to evaluate major environmental impact categories, including global impacts (e.g., carbon footprint, embodied energy) and local impacts (e.g., eutrophication potential). This is followed by an interpretation of results using sensitivity or uncertainty analysis. The scale assessment task investigates how scale impacts the environmental sustainability of three wastewater treatment systems integrated with resource recovery in a U.S. context. Household, community, and city scale systems using mechanized technologies applicable to a developed world setting were investigated. The household system was found to have the highest environmental impacts due high electricity usage for treatment and distribution, methane emissions from the septic tank, and high nutrient discharges. Consequently, the life cycle impacts of passive nutrient reduction systems with low energy usage at the household level merit further investigation. The community scale system highlights trade-offs between global impacts (e.g., embodied energy and carbon footprint) and local impacts (e.g., eutrophication potential) where low nutrient pollution can be achieved at the cost of a high embodied energy and carbon footprint. The city scale system had the lowest global impacts due to economies of scale and the benefits of integrating all three forms of resource recovery: Energy recovery, water reuse, and nutrient recycling. Integrating these three strategies at the city scale led to a 49% energy offset, which mitigates the carbon footprint associated with water reuse. The context assessment task investigates how context impacts the environmental sustainability of selected community scale systems in both Bolivia and the United States. In this task, rural developing world and urban developed world wastewater management solutions with resource recovery strategies are compared. Less mechanized treatment technologies used in rural Bolivia were found to have a lower carbon footprint and embodied energy than highly mechanized technologies used in urban United States. However, the U.S. community system had a lower eutrophication potential than the Bolivia systems, highlighting trade-offs between global and local impacts. Furthermore, collection and direct methane emissions had more important energy and carbon implications in Bolivia, whereas treatment electricity was dominant for the U.S. community system. Water reuse offsets of embodied energy and carbon footprint were higher for the U.S community system, because high quality potable water is replaced instead of river water. In contrast, water reuse offsets of eutrophication potential were high for the Bolivia systems, highlighting the importance of matching treatment level to end-use application. One of the Bolivia systems benefits from the integration of water, energy, and nutrient recovery leading to beneficial offsets of both global and local impacts. This research can potentially lead to transformative thinking on the appropriate scale of WWTPs with integrated resource recovery, while highlighting that context lead to changes in the dominant contributors to environmental impact, appropriate technologies, and mitigation strategies.
34

Urban Green Infrastructure: Modelling and Implications to Environmental Sustainability

January 2016 (has links)
abstract: The combination of rapid urban growth and climate change places stringent constraints on multisector sustainability of cities. Green infrastructure provides a great potential for mitigating anthropogenic-induced urban environmental problems; nevertheless, studies at city and regional scales are inhibited by the deficiency in modelling the complex transport coupled water and energy inside urban canopies. This dissertation is devoted to incorporating hydrological processes and urban green infrastructure into an integrated atmosphere-urban modelling system, with the goal to improve the reliability and predictability of existing numerical tools. Based on the enhanced numerical tool, the effects of urban green infrastructure on environmental sustainability of cities are examined. Findings indicate that the deployment of green roofs will cool the urban environment in daytime and warm it at night, via evapotranspiration and soil insulation. At the annual scale, green roofs are effective in decreasing building energy demands for both summer cooling and winter heating. For cities in arid and semiarid environments, an optimal trade-off between water and energy resources can be achieved via innovative design of smart urban irrigation schemes, enabled by meticulous analysis of the water-energy nexus. Using water-saving plants alleviates water shortage induced by population growth, but comes at the price of an exacerbated urban thermal environment. Realizing the potential water buffering capacity of urban green infrastructure is crucial for the long-term water sustainability and subsequently multisector sustainability of cities. Environmental performance of urban green infrastructure is determined by land-atmosphere interactions, geographic and meteorological conditions, and hence it is recommended that analysis should be conducted on a city-by-city basis before actual implementation of green infrastructure. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016
35

Building a Water-Energy Nexus Modelling Tool for New York City : Development of a NYC WaterMARKAL model

Segerström, Rebecka January 2011 (has links)
Increasing demands for energy and water from a growing urban population challenges resource availability and infrastructure capacity in cities worldwide. Planning for infrastructure systems development to meet growing demands has traditionally been done separately, not regarding that these systems are in many aspects interlinked. New York City has well developed systems for supplying these basic needs, but they are among the oldest in the country and may not suffice the needs of a growing population. Meanwhile, ambitious city-planning documents recognize opportunities for holistic planning focused on resource efficiency and long-term sustainability. This thesis aims to develop a foundation for quantitative modelling of how water and energy consumption may be affected by political decisions in New York City. The MARKAL (MARKet ALlocation) framework, commonly used to model long-term energy systems developments, is expanded to include the NYC’s water system. Relevant water system technologies are quantified with economic parameters, energy input and greenhouse gas emissions to give an as realistic as possible description of the entire water system. When combined with the existing MARKAL-model over NYC's energy system, the test runs of the model clearly shows impacts on energy consumption from water system regulations. These preliminary results are not applicable to support urban policy-making at this stage. However, with further development of the model as well as improvements in data quality it is perceived that this integrated water-energy model has the potential to become a powerful decision support tool for joint planning of water and energy systems developments in New York City. This Master thesis has been conducted in collaboration with the Energy Policy and Technology Analysis Group of the Sustainable Energy Technologies Department at Brookhaven National Laboratory, U.S.A.
36

Urban Living Labs som medel för samverkan och deltagande i mat-vatten-energi nexus : En fallstudie av CRUNCH Rosendal / Urban Living Labs as a means of collaboration and participation in the food-water-energy nexus : A case study of CRUNCH Rosendal

Gabrielsson, Louise January 2022 (has links)
Världens befolkning och städer växer. I takt med detta ökar efterfrågan på tillgångar av mat, energi och vatten och det finns efterfrågan på tillvägagångssätt som tar hänsyn till både synergier och konflikter mellan dessa. Ett projekt som syftade till att skapa kunskap inom dessa samband genom att använda så kallade Urban Living Labs, ULLs, var det transnationella projektet CRUNCH. Urban Living Labs kan beskrivas som en slags samling tillvägagångssätt som betonar experimentella tillvägagångssätt och en hög nivå av deltagande och samskapande. Men ULLs har visat sig kunna se mycket olika ut och den här studien är ett bidrag till den växande empirin inom ämnet. Studien analyserade hur en av de deltagande städerna inom CRUNCH arbetat med samverkan och samskapande och vilka hinder och möjligheter ULL har som tillvägagångssätt för deltagande, samverkan och samskapande. Detta gjordes genom en kvalitativ fallstudie av Uppsalas ULL Rosendal och analyserades genom teorier om deltagande och kollaborativ governance. Studien fann att deltagandet var smalt och främst skedde genom konsultation och information. De främsta möjligheterna till samarbete verkade vara de inledande villkoren och ett ömsesidigt beroende mellan parterna för att få finansiering till att utveckla sina idéer. De främsta hindren verkade finnas i en obalans i resurser vad gäller finansiering och möjligheter att delta. Men det kanske allra främsta hindret var dock en bristande delad förståelse av begreppet ULL. Begreppet sattes snarare som en ”stämpel” på projekt som redan fanns utan att tillföra dem något extra i form av deltagande eller samverkan. / The world's population and cities are growing. As the demand for food, energy and water resources increases there is a demand for approaches that consider both synergies and conflicts between them. One project that aimed to create knowledge in this nexus by using something called Urban Living Labs, ULLs, was the transnational project CRUNCH. Urban Living Labs can be described as a collection of approaches that emphasizes experimental approaches and a high level of participation and co-creation. But ULLs have been shown to take a variety of different forms and this study is a contribution to the growing empirical evidence in the subject. The study analysed how one of the participating cities within CRUNCH worked with collaboration and co-creation and what obstacles and opportunities ULL has as an approach for participation, collaboration, and co-creation. This was done through a qualitative case study of Uppsala's ULL Rosendal and analysed through theories of participation and collaborative governance. The study found that participation was narrow and mainly took place through consultation and information. The main opportunities for cooperation seemed to be the initial starting conditions and an interdependence between the partners to get funding to develop their ideas. The main obstacles seemed to be resource imbalances in terms of funding and means to participate. But perhaps the main obstacle was a lack of shared understanding of the main concept of ULL. The term was rather applied as a label on projects that already existed, without adding anything extra to them in terms of participation or collaboration.
37

Mathematical and Molecular Modeling of Ammonia Electrolysis with Experimental Validation

Estejab, Ali 14 June 2018 (has links)
No description available.
38

Water Supply Infrastructure Modeling and Control under Extreme Drought and/or Limited Power Availability

January 2019 (has links)
abstract: The phrase water-energy nexus is commonly used to describe the inherent and critical interdependencies between the electric power system and the water supply systems (WSS). The key interdependencies between the two systems are the power plant’s requirement of water for the cooling cycle and the water system’s need of electricity for pumping for water supply. While previous work has considered the dependency of WSS on the electrical power, this work incorporates into an optimization-simulation framework, consideration of the impact of short and long-term limited availability of water and/or electrical energy. This research focuses on the water supply system (WSS) facet of the multi-faceted optimization and control mechanism developed for an integrated water – energy nexus system under U.S. National Science Foundation (NSF) project 029013-0010 CRISP Type 2 – Resilient cyber-enabled electric energy and water infrastructures modeling and control under extreme mega drought scenarios. A water supply system (WSS) conveys water from sources (such as lakes, rivers, dams etc.) to the treatment plants and then to users via the water distribution systems (WDS) and/or water supply canal systems (WSCS). Optimization-simulation methodologies are developed for the real-time operation of water supply systems (WSS) under critical conditions of limited electrical energy and/or water availability due to emergencies such as extreme drought conditions, electric grid failure, and other severe conditions including natural and manmade disasters. The coupling between WSS and the power system was done through alternatively exchanging data between the power system and WSS simulations via a program control overlay developed in python. A new methodology for WDS infrastructural-operational resilience (IOR) computation was developed as a part of this research to assess the real-time performance of the WDS under emergency conditions. The methodology combines operational resilience and component level infrastructural robustness to provide a comprehensive performance assessment tool. The optimization-simulation and resilience computation methodologies developed were tested for both hypothetical and real example WDS and WSCS, with results depicting improved resilience for operations of the WSS under normal and emergency conditions. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2019
39

Podnikatelský záměr / Business project

Došek, Ladislav January 2008 (has links)
My business project is focused on foundation of a company using renewable resources to produce energy. I will compare individual variants of manufacturing energy using renewable resources and I will decide, which alternate I use for realization of my projekt.
40

Tepelné čerpadlo v trivalentním systému vytápění / Heat pump in multivalent heating system

Šedý, Martin January 2008 (has links)
Thesis deals with the usage of energy from recoverable resources. Theoretical part of thesis includes the description of the utilisation of heating pumps, solar radiation and biomass. The real status of the implementation is described in the second part of the thesis. Last part of the thesis contains the energy and economy valuation of real implementation.

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