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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.
1

Quantifying the energy consumption of the water use cycle

Trujillo, Iliana Cardenes January 2017 (has links)
The management and delivery of water and wastewater consume significant amounts of energy, mostly in the form of electricity. With increasing populations, climate change, water quality issues and increasing energy prices, it is more important than ever to understand energy consumption patterns. Energy usually represents the largest operational cost in water utilities around the world, yet there is limited work aiming to quantify the specific relationship between water and its associated energy, and understand its implications for future decision-making. This thesis presents variousmethodological approachesto quantify and understand energy use in water infrastructure systems, as well as how to incorporate them in decision-making processes. The main hypotheses are as follows: firstly, a detailed understanding of the use of energy in water infrastructure systems can facilitate more efficient and sustainable water infrastructure systems and, secondly, that incorporating energy into planning for water and wastewater resources can help understand the impacts of decisions and establish trade-offs between actions. To test these hypotheses, the thesis presents an analytical approach to various areas. Firstly, it identifies, maps and quantifies the energy consumption patterns within a water infrastructure system. This is then used to identify inefficiencies and areas of potential energy saving. Secondly, it incorporates detailed energy costs into short and long-term water resources management and planning. Thirdly, it evaluates trade-offs between energy costs and changing effluent quality regulations in wastewater resources. The Thames River basin, in the south-east of England, is used as a case study to illustrate the approach. The results demonstrate that a systematic approach to the quantification of energy use in a water infrastructure system can identify areas of inefficiencies that can be used to make decisions with regards to infrastructure planning. For example, water systems have significant geo-spatial variations in energy consumption patterns that can be addressed specifically to reduce negative trade-offs. The results also show that incorporating detailed energy information into long-term water resources planning can alter the choices made in water supply options, by providing more complete information. Furthermore, methodologically, they show how several methodological approaches can be used to support more complete decision-making in water utilities to reduce short and long-term costs. In this particular case study, the results show that there are important differences in energy consumption by region, and significant differences in the seasonal and energy patterns of water infrastructure systems. For example, water treatment was shown to be the largest consumer of energy within the whole system, compared with pumping or wastewater treatment; but wastewater treatment energy consumption was shown to be the fastest growing over time due to changes in water quality regulatory frameworks. The results show that more stringent effluent standards could result in at least a doubling of electricity consumption and an increase of between 1.29 and 2.30 additional million tonnes of CO2 a year from treating wastewater in large works in the UK. These are projected to continue to increase if the decarbonisation of the electricity grid does not occur fast enough. Finally, the thesis also shows that daily energy consumption can be reduced by up to 18% by optimally routing water through a water network. optimization of water networks, and that a change in discount rates could change the daily operating costs by 19%, that in turn leads to a resulting different set of optimal investment options in a water supply network.
2

Thermal comfort study on a renovated residential apartment in Tjärna Ängar, Borlänge

Mnla Ali, Tammam January 2021 (has links)
The Swedish government in the 1960th initiated “The Million Program” to build million residentialunits to cover the housing shortage between 1965 to 1975. Tjärna Ängar neighborhood in Borlängemunicipality was built during the million-program period, where these residential units became old,and the indoor environment is uncomfortable for the residents.Recently, there have been extensive energy-efficient renovations to improving the energyefficiency,indoor air quality, and thermal comfort of these buildings. The renovation project, withcooperation between Dalarna University and the local housing company (Stora Tunabyggen)started in 2015 by renovating three buildings in the Tjärna Ängar neighborhood.This study was conducted at one of these three retrofitting buildings (Kornstigen 25) to investigatethe thermal comfort in the building following energy retrofit. The assessment of the thermalcomfort in this study is based on Fanger's model with the use of predicted mean vote (PMV) andpredicted percentage of dissatisfied (PPD) to assess the obtained measurements.An online questionnaire survey with building occupants was conducted to give a betterunderstanding of the current situation of the retrofitting building before and after the renovationregarding thermal comfort. Based on the measurement, the thermal sensation of the occupants isslightly cool according to the standard’s sensation scale during the period of the measurement. Anonline questionnaire survey assures that the occupants were feeling slightly cool during someperiods of the day inside the apartments.
3

Advancement of direct drive generator systems for offshore renewable energy production

Burchell, Joseph William January 2018 (has links)
As machine topologies and technologies mature, the fundamental function of the device is honed. Direct drive machines have the potential to launch the renewable energy sector into a new era of large scale, reliable, offshore power generation. With advancements in new technologies, such as superconductivity, the reduction of generator mass due to incorporation of machine and device structures, the continued advancements in component and system reliability; direct drive generators have the ability to outsize geared wind systems and simplify submerged linear and rotary power generation. The research held within this thesis will focus on improving direct drive power take off systems for offshore renewable energy power generation by splitting the area into four parts. The first part will discuss the various methods of energy extraction within the offshore and marine environment. The future of the sector will be discussed, and a forecast of technological advancement and existing reliability issues will be provided based on current data. The second part will focus on drive trains and direct drive generators, assessing the current topologies and suggesting alternatives that may thrive in a variety of large and small offshore renewable machines. The third part investigates the application of novel linear bearings in direct drive systems for offshore and submerged operation. A brief study of the loads found in wave applications will be presented and the testing of several polymer bearing materials will be outlined. The final part will discuss the potential benefits of flooding the airgap of a direct drive generator with sea water for marine applications. Results will be presented from two linear test rigs and the marinisation of devices will conclude the report.
4

Retrofitting the domestic built environment : investigating household perspectives towards energy efficiency technologies and behaviour

Pelenur, Marcos January 2014 (has links)
Retrofitting the UK domestic built environment presents an excellent opportunity to improve its energy performance. However, retrofitting homes is a complex challenge conflated by multiple factors. Due to this complexity, a shortfall exists between the full potential and realised adoption of energy efficiency measures in the UK, a phenomenon termed the ‘Energy Efficiency Gap’. While a number of technical or economic factors may help explain this gap, difficult to quantify factors, such as social motivations, barriers, and viewpoints towards energy are also significant and often under-emphasised in public policy. As such, in order to improve the understanding of the Energy Efficiency Gap and the uptake of future retrofit initiatives, this research adopted a socio-technical approach that considered social and technical retrofit factors together. Specifically, this research collected data from interviews, questionnaires, and a Q Study in the cities of Manchester and Cardiff, alongside a questionnaire that measured energy efficiency technology and behaviour preferences. An original contribution to knowledge was using the data to empirically identify motivations and barriers to adopting energy efficient technologies, as well as identifying household viewpoints towards energy use and linking them to retrofit technology and energy efficiency behaviour preferences. As a result of this research, specific policy recommendations are presented to help promote energy efficiency retrofits in the UK. This research was carried out as part of the Engineering & Physical Science Research Council and Sustainable Urban Environment research programme, “Re-Engineering the City 2020-2050 Urban Foresight and Transition Management (RETROFIT 2050)”.
5

Jaderná energie v České republice / Nuclear energy in the Czech Republic

Bosáková, Lenka January 2008 (has links)
This thesis deals with the topic of nuclear energy. The Czech Republic is currently a net electricity exporter however this status will probably change in next few years because of growing electricity consumption and decommissioning of obsolete coal-fired power plants. Moreover, contemporary government declared that it won't approve any construction of new reactors stressing the importance of renewable sources of energy (in spite of their limited potential in the Czech Republic). The goal of this thesis is to answer the question whether nuclear energy can compete with other sources of energy and whether is it possible to satisfy growing electricity consumption under the conditions of the Czech Republic by any other source of electricity besides nuclear energy taking into account environmental aspects.
6

Energetické využití biomasy - kontroverzní environmentální téma / Energetic utilisation of biomass - controversial environmental topic

Zumrová, Kateřina January 2015 (has links)
The thesis is focused on energetic utilisation of biomass. It was used a qualitative research and document analysis of articles. The first part deals with the theoretical framework, therefore definitions and possibilities of biomass utilisation. The second part contains methodology, follows research and its evaluation. The first aim of this thesis is to summarize the utilisation of biomass as renewable energy and to distinguish positive and negative impacts of the utilisation of this source and evaluate its economic efficiency. There are several possibilities of utilisation of biomass, but it is necessary to select the suitable process and its utilisation. Based on the large number of examples from life it can be stated that it is economically efficient. The second aim is to identify main misconceptions related to utilisation of biomass. The main misconception is comparing the utilisation of solar energy, which has not left positive attitude of people to renewable energy, with utilisation of biomass. There are few examples of comparing photovoltaic with utilisation of biomass on the same level. In regard of the basic principles of utilisation of biomass, those two sources cannot be compared at all, they are not similar. Another misconception is apprehension of appropriation of land used for growing energy...
7

Energetika v EU: současné trendy / Energetics in the EU: Present Trends

Procházková, Lenka January 2009 (has links)
The first chapter of the diploma thesis describes Energy policy of the European Union, especially its development, present state and its goals. This chapter also contains information about development of the single energy market. The second part of the thesis analyses oil and natural gas import dependence of the whole European Union and its Member States as well. It shows its rate and also the structure of suppliers, moreover, it describes total production, consumption and reserves of these fosil fuels. The third chapter outlines the ways how to reduce the import dependence. The last part familiarises readers with the main initiatives of the European Union in the field of environmental protection.
8

Saggi sull'energia e lo sviluppo in Africa subsahariana: l'accesso all'energia, il cambiamento climatico e il Nexus / ESSAYS ON ENERGY AND DEVELOPMENT IN SUB-SAHARAN AFRICA. ENERGY ACCESS, CLIMATE CHANGE, AND THE NEXUS / Essays on Energy and Development in sub-Saharan Africa: Energy access, climate change, and the Nexus

FALCHETTA, GIACOMO 20 July 2021 (has links)
La seguente Tesi di Dottorato si articola in cinque saggi che esaminano alcuni importanti aspetti legati all'energia in Africa subsahariana, e in particolare all'interazione tra lo sviluppo socio-economico e le sue implicazioni per l'ambiente a livello regionale e globale. I saggi sono introdotti da un capitolo di avvicinamento generale ai temi trattati. Questo capitolo prepara il lettore offrendo un riassunto delle principali sfide legate all'energia nel contesto subsariano e formulando le domande di ricerca e gli strumenti sui quali si basa la tesi stessa. Le principali implicazioni di ciascuno dei saggi, sia per la ricerca che per i decisori politici, vengono poi presentate in un capitolo di discussione finale. Il primo saggio esamina la problematica dell’accesso all'energia, e in particolare all'elettricità. Viene illustrato il ruolo dei dati satellitari e dell'analisi statistica dei dati geospaziali nel migliorare la comprensione della situazione dell'accesso all'elettricità in Africa subsahariana. Il saggio include un'analisi delle disuguaglianze che caratterizzano la qualità dell'accesso all'elettricità nella regione. Il risultato principale è che, dopo decenni, la disuguaglianza nell'accesso all'energia sta iniziando a diminuire. Essa rimane però prominente, in particolare per quanto riguarda la quantità di energia consumata. Viene stimato che gli sforzi di elettrificazione tra il 2020 e il 2030 debbano triplicare il loro passo per raggiungere l'obiettivo di sviluppo sostenibile SDG 7.1.1. Il secondo saggio consiste di una piattaforma di valutazione della domanda energetica bottom-up spazialmente esplicita per stimare il fabbisogno energetico tra le comunità in cui l'accesso all'elettricità è attualmente carente, come identificato con la metodologia introdotta nel primo saggio. La valutazione non si limita al fabbisogno energetico residenziale, ma include un resoconto dettagliato, basato sugli usi finali, del fabbisogno energetico di scuole, strutture sanitarie, pompaggio dell'acqua per l'irrigazione, lavorazione delle colture e microimprese, i principali motori dello sviluppo rurale. Viene condotto uno studio nazionale per il Kenya per dimostrare l'importanza di considerare molteplici fonti di domanda oltre al residenziale quando l'obiettivo è sviluppare una strategia di elettrificazione che supperisca veramente alla povertà energetica. Si dimostra poi che esiste un notevole potenziale di crescita della produttività e della redditività rurale grazie all'apporto di energia elettrica. In molte aree, questi profitti locali potrebbero ripagare gli investimenti nelle infrastrutture di elettrificazione in pochi anni. Il terzo saggio analizza un aspetto specifico dell'interazione tra pianificazione dell'accesso all'elettricità, domanda di energia residenziale e adattamento ai cambiamenti climatici. Vengono combinati dati e scenari climatici, satellitari e demografici per produrre una stima globale spazialmente esplicita della domanda di circolazione e condizionamento dell’aria non soddisfatta a causa della mancanza di accesso all'elettricità. Sulla base di modelli integrati di elettrificazione climatica-energetica e geospaziale, risulta che in Africa sub-sahariana, l'hotspot globale della povertà energetica, tenere conto del fabbisogno di circolazione e condizionamento dell’aria locale stimato (in aggiunta agli obiettivi di consumo residenziale di base) determini una riduzione sostanziale della quota di sistemi standalone come l'opzione di elettrificazione meno costosa entro il 2030, e un importante aumento della capacità di generazione di elettricità e dei requisiti di investimento. Tali risultati suggeriscono la necessità di una maggiore considerazione delle esigenze di adattamento climatico nella pianificazione dei sistemi energetici dei paesi in via di sviluppo e nella valutazione del trade-off tra l'espansione della rete elettrica centrale e sistemi decentralizzati per raggiungere un’elettrificazione universale. La pianificazione dell'elettrificazione deve essere tecnicamente efficiente, ma deve anche considerare l'ambiente politico-economico in cui gli investimenti vengono canalizzati. Il quarto saggio valuta il ruolo della governance e della qualità regolatoria nel quadro di modellazione dell'accesso all'energia elettrica. In particolare, si introduce un indice di governance dell'accesso all'elettricità basato su più indicatori che viene poi implementato nel modello di elettrificazione IMAGE-TIMER. L’effetto dell’indice viene modellato attraverso il suo effetto modificatore sui tassi di sconto privati (una misura del rischio e della disponibilità ad accettare costi futuri rispetto ai costi attuali). I risultati mostrano che la governance e la qualità regolatoria nell'accesso all'elettricità hanno un impatto significativo sul mix tecnologico ottimale e sui flussi di investimenti privati per raggiungere l'elettrificazione universale in Africa subsahariana. In particolare, un ambiente rischioso scoraggia l’investimento da parte dei fornitori privati di soluzioni di accesso decentralizzato all'energia, con il rischio di lasciare molti senza elettricità anche oltre il 2030. Il quinto e ultimo saggio analizza il settore energetico africano da un punto di vista ‘Nexus’. Il saggio valuta l'affidabilità del sistema energetico nei sistemi energetici dominati dall'energia idroelettrica (come in molti paesi dell'Africa centrale e orientale) e del ruolo che i cambiamenti climatici e gli eventi estremi possono esercitare su di esso. Il lavoro combina analisi qualitative e quantitative per (i) proporre un solido framework per evidenziare le interdipendenze tra energia idroelettrica, disponibilità di acqua e cambiamento climatico, (ii) analizzare sistematicamente lo stato dell'arte sugli impatti previsti dei cambiamenti climatici su l'energia idroelettrica nell'Africa subsahariana e (iii) fornire evidenza empirica sui trend passati e sulle traiettorie di sviluppo futuro del settore. I risultati suggeriscono che il cambiamento climatico influenzerà l'affidabilità e la sicurezza della fornitura elettrica attraverso diversi canali. Ad esempio, molti dei principali bacini idrologici sono stati caratterizzati da una diminuzione del livello idrico nel corso del ventesimo secolo. Si evidenzia come tuttavia una diversificazione del mix di generazione elettrico sia finora stata promossa solo in un numero limitato di paesi. Si suggerisce infine che l'integrazione delle fonti rinnovabili variabili con l'energia idroelettrica possa aumentare la resilienza del sistema. / This dissertation is a collection of five essays examining some important energy-related aspects at the interplay of sub-Saharan Africa (SSA)’s development and its interactions with the regional and global environment. The essays are introduced by a general overview chapter – highlighting the core energy-related challenges of SSA and the scope of this work. The main implications of the essays, both for research and for policymakers, are then considered in the final discussion chapter. The first essay focuses on access to modern energy, and chiefly on electricity. I illustrate the role of satellite data and the statistical analysis of geospatial data in improving the understanding of the electricity access situation in sub-Saharan Africa. The essay includes an analysis of inequality characterising the electricity access quality in the region. The main finding is that after decades, energy access inequality is beginning to decline but it remains prominent in particular as far as the quantity consumed is concerned. I find that electrification efforts between 2020 and 2030 must triplicate their pace to meet Sustainable Development Goal 7.1.1. The second essay develops a spatially-explicit bottom-up energy demand assessment platform to estimate the energy needs among communities where access to electricity is currently lacking, as identified with the methodology introduced in the first essay. The assessment is not restricted to residential energy needs, but it includes a detailed, appliance-based account of power needs for schools, healthcare facilities, water pumping for irrigation, crop processing, and micro enterprises, the key drivers of rural development. I carry out a country-study for Kenya to show the importance of considering multiple demand sources beyond residential when the aim is developing an electrification strategy which truly overcomes energy poverty. I also show that there is considerable potential for rural productivity and profitability growth thanks to the input of electric energy. In many areas, these local profits might pay back the electrification infrastructure investment in only few years. The third essay analyses a specific aspect at the interplay between electricity access planning, household energy demand and climate change adaptation. I combine climate, satellite, and demographic data and scenarios to produce a global spatially-explicit estimate of unmet ACC demand due to the lack of electricity access. Based on integrated climate-energy and geospatial electrification modelling, I find that in sub-Saharan Africa, the global hotspot of energy poverty, accounting for the estimated local ACC needs on top of baseline residential consumption targets determines a substantial reduction in the share of decentralised systems as the least-cost electrification option by 2030, and a major ramp-up in the power generation capacity and investment requirements. My results call for a greater consideration of climate adaptation needs in the planning of energy systems of developing countries and in evaluating the trade-off between the central power grid expansion and decentralised systems to achieve universal electrification. Electrification planning must be techno-economically efficient, but it must also consider the political-economic environment where investment needs to be channelled. The fourth essay evaluates the role of governance and regulatory quality in the electricity access modelling framework. In particular, I introduce an Electricity Access Governance Index based on multiple indicators implement it into the PBL’s IMAGE-TIMER electrification model through its modifier effect on private discount rates (a measure of risk and willingness to accept future costs vis-à-vis present costs). The results show that governance and regulatory quality in electricity access have a significant impact on the optimal technological mix and the private investment flows for reaching universal electrification in sub-Saharan Africa. In particular, risky environment crowd out private providers of decentralised energy access solutions with the risk of leaving many without electricity even after 2030. The fifth and final essay takes a nexus perspective in the analysis of the African power sector. It deals with the reliability of the energy system in hydropower-dominated power systems (such as in many countries in Central and East Africa) and the role that climate change and extreme events can exert on it. The essay combines qualitative and quantitative analysis to (i) propose a robust framework to highlight the interdependencies between hydropower, water availability, and climate change, (ii) systematically review the state-of-the art literature on the projected impacts of climate change on hydropower in sub-Saharan Africa, and (iii) provide supporting evidence on past trends and current pathways of power mix diversification, drought incidence, and climate change projections. I find that climate change can affect supply reliability and security in multiple ways. For instance, several major river basins have been drying throughout the twentieth century. Nonetheless, I highlight that diversification has hitherto only been promoted in a limited number of countries. I suggest how integrating variable renewables and hydropower can increase system resilience.
9

Potencialidade energética e o perfil socioeconômico do estado de Alagoas. / Potentiality energy and the profile socioeconomic of the state of Alagoas.

Omena Neto, Alcides José de 29 October 2007 (has links)
In the function of the current society, the energy is an variable of total importance. It does not have much that to think about growth and development, without this matrix is inserted. That the taken routes only need to be reviewed, and certain incorporated concepts already to the effective system, and, that, until then, seen as untouchable, they urgently need a to formulate how much its technician-scientific action. This process of appropriation of materials of the nature for the production of goods and services in order to take care of the necessities of the society, some concepts of civilities seem to have been forgotten, and the search for the full comfort leads to the man to interact of incoherent form, in view of the exhaustion of the reserves of natural resources, establishing, thus, the degradation in such a way of the ecological environment as the social environment. This way operands, is that it is studied as form to quantify and to characterize the actions human beings in main its input the energy, comparing the direct relation enters of energy and the economic and social development; to analyze the energy in the World, Brazil and the State of Alagoas, to see the producing relation versus energy consumer, the energy matrices, to also compare the economic development with the production of energy and with regard to its consumption. To take to the field of the academic quarrel the questioning of the production and the consumption of electric energy, alternatives you renewed and of low ecological impact. To quantify how much it is produced, how much it is consumed. To characterize who produces and who consumes, and, the one that level. Measurer, and form economically and accounting, the ambient and social impacts of the production and the consumption, here it is the question. / Na função da sociedade atual, a energia é uma variável de total importância. Não há muito que pensar em crescimento e desenvolvimento, sem que esta matriz esteja inserida. Só que os rumos tomados precisam ser revistos, e certos conceitos já incorporados ao sistema vigente, e, que, até então, vistos como intocáveis, necessitam urgentemente de uma reformulação quanto a sua ação técnico-científica. É durante o presente processo de apropriação de materiais da natureza para a produção de bens e serviços a fim de atender as necessidades da sociedade, que alguns conceitos de civilidades parecem ter sidos esquecidos, e a busca pelo conforto pleno leva ao homem interagir de forma incoerente na natureza, tendo em vista a exaustão das reservas de recursos naturais, estabelecendo, assim, o atual quadro de degradação tanto do meio ambiente ecológico como o meio ambiente social. Busca-se em forma de estudo uma formatação mais próxima da realidade do mundo atual, como forma de quantificar e qualificar as ações humanas no seu insumo principal a energia, comparando a relação direta entre a energia e o desenvolvimento econômico e social; analisar a energia no Mundo, no Brasil e no Estado de Alagoas, ver a relação produtor versus consumidor de energia, as matrizes energéticas, comparar o desenvolvimento econômico com a produção de energia e também com relação ao seu consumo. Levar ao campo da discussão acadêmica o questionamento da produção e do consumo de energia elétrica, alternativas renováveis e de baixo impacto ecológico. Quantificar o quanto se produz, o quanto se consome. Qualificar quem produz e quem consome. Medir de forma econômica e contabil, os impactos ambientais e sociais da produção e do consumo, eis a questão.
10

The impact of 100kWh free electricity on meeting the energy needs of poor urban households

Lourens, Karin 02 1900 (has links)
Energy poverty is a major obstacle to human development. Energy services supply the benefits that “trigger” wider social and economic changes and create the conditions for improving social equality and economic growth. The South African government has scaled up electricity access to its poor population to such an extent that 85% of the country’s population had access to electricity in 2017. Nevertheless, access to electricity is not the same as the ability to use it, as the poor find the price of electricity unaffordable. The government therefore embarked on a programme to provide households’ that they consider ‘indigent’ or ‘poor’ 50kWh of free energy. This is criticized by many as not being enough to sufficiently satisfy household energy needs. Even the generous supply of 100kWh electricity provided by the City of Tshwane and the City of Johannesburg municipalities is considered to be insufficient. This study investigates the impact of the 100kWh free basic electricity subsidy on the energy use of the urban poor in the township of Soshanguve in the City of Tshwane municipality. It focuses on whether the 100kWh is enough to meet these household’s’ energy needs. The finding of the study is that the 100kWh FBE is enough to meet these households’ needs for lighting, some cooking and appliance use, but not for space and water heating. / Development Studies / M.A. (Development Studies)

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