• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 128
  • 12
  • 12
  • 7
  • 6
  • 6
  • 4
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 196
  • 196
  • 62
  • 48
  • 47
  • 38
  • 36
  • 28
  • 27
  • 26
  • 26
  • 25
  • 25
  • 24
  • 23
  • 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.
41

Assessment of business opportunities forutilities in distributed battery storage forhousehold consumers in Germany

GUSTAFSSON, OSCAR, Maiorana, Johanna January 2016 (has links)
The German initiative Energiewende aims to decrease their dependence on nuclear andfossil-based energy, and to increase the share of variable renewable energy sources (V-RES).This transformation calls for new technical solutions that can meet future stakeholderneeds. Distributed battery storage (DBS), which can be used as a complement to theunreliable V-RES, is such a solution.In this thesis, the possibilities for incorporating DBS into the German energy market werefirst analyzed. This was followed by calculations of the economic potential for DBS, and lastlya possible business model for Vattenfall associated with the identified businessopportunities was developed. The assessment shows big opportunities of incorporating DBSinto the future energy system since it can increase the reliability and stability of thedecentralized generation of V-RES. DBS will also be the cheapest solution for an averagehousehold 2030, making the technology a profitable solution. A suitable business model hasalso been identified for Vattenfall, which focuses on the activities of leasing the DBS-units toprosumers and utilizing excess capacity for ancillary services to TSO’s and DSO’s. Theancillary services that can be utilized include frequency regulation and peak shaving.Theoretically the thesis contributes with knowledge about the increasing possibilities of DBSbecoming a large part of the future German power system. The thesis will also be a practicaltool for utilities on how to adapt their business offering with regards to the new market.
42

System Simulation of Thermal Energy Storage involved Energy Transfer model in Utilizing Waste heat in District Heating system Application

Garay Rosas, Ludwin January 2015 (has links)
Nowadays continuous increase of energy consumption increases the importance of replacing fossil fuels with renewable energy sources so the CO2 emissions can be reduced. To use the energy in a more efficient way is also favorable for this purpose. Thermal Energy Storage (TES) is a technology that can make use of waste heat, which means that it can help energy systems to reduce the CO2 emissions and improve the overall efficiency. In this technology an appropriate material is chosen to store the thermal energy so it can be stored for later use. The energy can be stored as sensible heat and latent heat. To achieve a high energy storage density it is convenient to use latent heat based TES. The materials used in this kind of storage system are called Phase Change Materials (PCM) and it is its ability of absorbing and releasing thermal energy during the phase change process that becomes very useful. In this thesis a simulation model for a system of thermal energy transportation has been developed. The background comes from district heating systems ability of using surplus heat from industrials and large scale power plants. The idea is to implement transportation of heat by trucks closer to the demand instead of distributing heat through very long pipes. The heat is then charged into containers that are integrated with PCM and heat exchangers. A mathematical model has been created in Matlab to simulate the system dynamics of the logistics of the thermal energy transport system. The model considers three main parameters: percentage content of PCM in the containers, annual heat demand and transport distance. How the system is affected when these three parameters varies is important to visualize. The simulation model is very useful for investigation of the economic and environmental capability of the proposed thermal energy transportation system. Simulations for different scenarios show some expected results. But there are also some findings that are more interesting, for instance how the variation of content of PCM gives irregular variation of how many truck the system requires, and its impact on the economic aspect. Results also show that cost for transporting the heat per unit of thermal energy can be much high for a small demands compared to larger demands.
43

Trimming of a ground source heat pump system in Saltsjöbaden

Garnier, Michel January 2014 (has links)
The real performance of ground source heat pumps systems are not precisely highlighted in most cases, especially when it comes to installations older than the contractors guarantee period of 5 years. This project analyses measured data, constructs durability diagrams and establishes an energy balance of a whole heating system located in Saltsjöbaden. The system, composed of 3 heat pumps with a total heating power of 270kW and an oil burner, is used to deliver comfort heat through radiators and ventilation as well as tap warm water production. The installation was originally designed with two oil burners now used as an auxiliary heat supplier. Two heat pumps were installed in 1999 and a third unit was added in 2009. However, the oil consumption has been higher than expected. An experiment with controlled oil burner operation confirmed the need of implementing a control strategy. Some weaknesses in the system are pointed out.
44

Energy services for high performance buildings and building clusters - towards better energy quality management in the urban built environment

Marmoux, Pierre-Benoît January 2012 (has links)
With an increasing awareness of energy consumption and CO 2emission in the population, several initiatives to reduce CO2emissions have been presented all around the world. The main part of these initiatives is a reduction of the energy consumption for existing buildings, while the others concern the building of eco-districts with low-energy infrastructures and even zero-energy infrastructures. In this idea of reducing the energy consumption and of developing new clean areas, this master thesis will deal with the high energy quality services for new urban districts. In the scope of this master thesis project, the new concept of sustainable cities and of clusters of buildings will be approached in order to clearly understand the future challenges that the world’s population is going to face during this century. Indeed, due to the current alarming environmental crisis, the need to reduce human impacts on the environment is growing more and more and is becoming inescapable. We will present a way to react to the current situation and to counteract it thanks to new clean technologies and to new analysis approaches, like the exergy concept. Through this report, we are going to analyze the concepts of sustainable cities and clusters of buildings as systems, and focus on their energy aspects in order to set indoor climate parameters and energy supply parameters to ensure high energy quality services supplies to high performance buildings. Thanks to the approach of the exergy concept, passive and active systems such as nocturnal ventilation or floor heating and cooling systems have been highlighted in order to realize the ‘energy saving’ opportunities that our close environment offers. This work will be summarized in a methodology that will present a way to optimize the energy use of all services aspects in a building and the environmental friendly characteristics of the energy resources mix, which will supply the buildings’ low energy demands.
45

Techno-economic Assessment of Wind Energy to Supply the Demand of Electricity for a Residential Community in Ethiopia

Yebi, Adamu January 2011 (has links)
The electricity sector is a major source of carbon dioxide emission that contributes to the global climate change. Over the past decade wind energy has steadily emerged as a potential source for low carbon energy source which are grown through time. As wind power generation increases around the world, there is increasing interest in adding intermittent power to the electricity grid and to design an off-grid wind energy system. The goal of the current thesis is to investigate techno-economically viable wind energy system that supplies electricity and Heat for a given residential community in Ethiopia. To ease the optimization process, HOMER software is used to identify the potential wind area and optimize cost effective wind energy system.
46

Framgångsfaktorer och fallgropar vid utveckling av energisystem i nya stadsdelar : En fallstudie på Ebbepark i Linköping / Success factors and difficulties in the development of energy systems in new districts : A case study at Ebbepark in Linköping

Martinsson, Lovisa, Schill, Sofia January 2021 (has links)
Två tredjedelar av världens växthusgasutsläpp kommer från energianvändning varpå de klimatutmaningar som världen står inför till stor del är en energirelaterad utmaning. Sverige har som mål att uppnå 50% effektivare energianvändning till 2030 jämfört med 2005. Eftersom bostads- och servicesektorn står för 40% av landets totala energianvändning behöver sektorn genomföra förändringar för att målen ska kunna uppnås. Även byggsektorn blir berörd och där finns behov av att gå ifrån traditionella metoder. Nuvarande projekt behöver utvärderas för att kunna dra lärdomar till kommande projekt. Kommuniceras inte lärdomar vidare finns risk att misstag återupprepas.  Sankt Kors, ett kommunalt fastighetsbolag med fokus på kontorsverksamhet, är drivande i utvecklingen av stadsdelen Ebbepark i Linköping. Stadsdelen ska vara energisnål med fokus på innovation för att energieffektivisera energianvändningen. Denna studie bidrar till att, genom utvärdering av energisystemet i Ebbepark, identifiera framgångsfaktorer och fallgropar som kan beaktas vid kommande utformning av energisystem i nya stadsdelar. Utvärdering har gjorts i förhållande till funktion, miljömässig hållbarhet och socioteknisk utformning. Studiens kartläggning av energisystemet och undersökning av dess framväxt visat att det finns flertalet såväl tekniska som sociala aspekter som påverkar utformningen av energisystem. Det är därför av hög relevans att applicera ett sociotekniskt perspektiv.  Kartläggning av Ebbeparks energisystem visade att det tekniska systemet inkluderar flöden för att tillgodose byggnadens energibehov vilka i fallet är fjärrvärme, fjärrkyla, el från kraftnätet, el från solceller samt värme och kyla från geolager. Det sociala systemet inkluderar bland annat projektledning, beslutsfattare, driftpersonal och användare. Med andra ord både de som utvecklar systemet liksom de som i slutändan brukar det. Sociala systemet inkluderar genom dessa grupper också kommunikation, dokumentation och icke-tekniska artefakter.  Utvärdering av energisystemet och dess framväxt visar på flera fallspecifika faktorer som bidrar till att uppnå funktion och miljömässig hållbarhet, men att systemets utformning och därmed användning kan vara suboptimerat och därmed till viss del inte uppfylla socioteknisk utformning. Främst konstateras fallspecifika fallgropar gälla driftöverlämning och infasning för systemet vilka varit korta i förhållande till systemets komplexitet och omfattning. Vidare konstateras problem kring hur kunskap integreras i verksamheten, resursåtgång vid framtagande av dokument samt relevans av dokument också bli fallgropar. Fallspecifika framgångsfaktorer rör främst de tekniska komponenterna där komponenterna kan ses som framgångsfaktorer i sig men där kombinationen och helheten bidrar till att både minskad klimatpåverkan, flexibilitet, energieffektivisering och energiprestandamål uppnås.  Flera av de framgångsfaktorer och fallgropar som identifierats för Ebbepark anses inte vara generaliserbara eftersom varje stadsdel har sina unika förutsättningar. De framgångsfaktorer som identifierats kan konstateras främst röra den tekniska delen av energisystemet medan fallgroparna rör den sociala delen. Det tycks generellt finnas ett större fokus på optimering av det tekniska systemet än det sociotekniska. / Two thirds of the world ́s green gas emissions emerge from energy use, whereupon the climate challenges facing the world are largely an energy related challenge. Sweden aims to achieve a 50% more efficient energy use by 2030 compared with 2005. Since the housing and service sector accounts for 40 % of Sweden’s total energy use, the sector needs to implement changes in order to achieve the goals. The building sector is also a relevant part and it needs to change its’ traditional methods. Evaluation of current projects enables for lessons to be learned which can be used in future projects. If lessons are not communicated to future projects, there is a risk that mistakes will be repeated.  Sankt Kors, a municipal real estate company with a focus on office operations, is a driving force in the development of the Ebbepark district in Linköping. The district will be energy-efficient with focus on innovation to make energy use more efficient. This study helps to, through evaluation of the energy system in Ebbepark, identify success factors and difficulties that can be considered in the future design of energy systems in new districts. Evaluation has been made in relation to function, environmental sustainability and sociotechnical design. By mapping the energy system and examining its emergence, the study has shown that there are several technical and social aspects that affect the design of energy systems. It is therefore of high relevance to apply a socio-technical perspective.  Mapping of the energy system shows that the technical system includes flows intended to meet the building's energy needs, which in the case of Ebbepark means district heating, district cooling, electricity from the power grid, electricity from solar cells and heating and cooling from geoenergy storage. The social system includes, among others, project management, decisionmakers, operating staff and users. In other words, both those who develop the system as well as those who ultimately use it. Through these groups, the social system also includes communication, documentation and non- technical artifacts.  Evaluation of the energy system and its emergence shows several case specific factors that contribute to achieve function and environmental sustainability, but that the design of the system and thus its use, may be sub optimized and therefore partially not achieve sociotechnical design. Identified case specific difficulties mainly regard operational handover and technical adjustment. Technical adjustment and learning period of the system has been too short in relation to the system's complexity and scope. Furthermore, problems regard how knowledge is integrated into the business, resource consumption when bringing forth documents and the relevance of documents. Case specific success factors mainly concern the technical components where the components can be seen as sucessfactors themselves, but that the combination of the technologies and the system as a hole contributes to both reduced climate impact, flexibility, energy efficiency and achieving energy performance.  Several of the success factors and difficulties identified for Ebbepark are not generalizable because of each districts’ unique conditions. The success factors mainly concern the technical part of system while the difficulties concern the social part. In general, there seems to be a greater focus on optimizing the technical system rather than the sociotechnical one.
47

Holistic and integrated energy system optimization in reducing diesel dependence of Canadian remote Arctic communities

Quitoras, Marvin Rhey D. 17 September 2020 (has links)
This dissertation demonstrates novel holistic approaches on how to link policy, clean energy innovations, and robust energy modeling techniques to help build more resilient and cost-effective energy systems for the Canadian Arctic region and remote communities in general. In spite of the diversity among Arctic jurisdictions, various energy issues and challenges are shared pan-territorially in the North. For instance, 53 out of 80 remote communities in the Northern territories rely exclusively on diesel-based infrastructures to generate electricity, with heating oil as their primary source of heat. This critical dependence on fossil fuels exposes the Indigenous peoples and other Canadians living in the North to high energy costs and environmental vulnerabilities which is exacerbated by the local and global catastrophic effects of climate change in the Arctic. Aside from being strong point sources of greenhouse gases and other airborne pollutants, this reliance on carbon-intensive sources of energy elevates risk of oils spills during fuel transport and storage. Further, conventional transportation mode via ice roads is now increasingly unreliable because of the rising Arctic temperatures which is twice the global average rate. As a result, most fuels are being transported by small planes which contribute to high energy costs and fuel poverty rates, or via boats which also increases the risk of oil spills in the Arctic waters. Methodologically, this thesis presents a multi-domain perspective on how to accelerate energy transitions among Northern remote communities. In particular, a multi-objective optimization energy model was developed in order to capture complex trade-offs in designing integrated electrical and thermal energy systems. In comparison with traditional single-objective optimization approach, this technique offers diversity of solutions to represent multiple energy solution philosophies from various stakeholders and practitioners in the North. A case study in the Northernmost community of the Northwest Territories demonstrates the applicability of this framework - from modeling a range of energy solutions (supply and demand side aspects) to exploring insights and recommendations while taking into account uncertainties. Overall, this dissertation makes a set of contributions, including: (i) Development of a robust energy modeling framework that integrates complex trade-offs and multiple overlapping uncertainties in designing energy systems for the Arctic and remote communities in general; (ii) Extension of previous Arctic studies - where focused has solely been on the electricity sector - by integrating heating technology options in the proposed modeling framework in conjunction with methods on obtaining `high performance' buildings in the North; (iii) Overall energy system performance evaluation when integrating heat and electricity sectors, as well as the role of battery storage systems and diesel generator on facilitating variable renewable energy generation among isolated communities; (iv) Formulation of a community-scale energy trilemma index model which helps design policies that are accelerating (or hindering) energy transitions among remote communities by assessing quantitatively challenges relating to energy security, affordability, and environmental sustainability; (v) Synthesized holistic insights and recommendations on how to create opportunities for Indigenous peoples-led energy projects while discussing interwoven links between energy system operations, relationship building and stakeholders engagement, policy design, and research (energy modeling and analysis). Collectively, the new methods and recommendations demonstrated herein offer evidence-based decision making and innovative solutions for policy makers, utility companies, Indigenous peoples, and other stakeholders in the Arctic and beyond. / Graduate
48

Economic Analysis of Sustainable Spatial Allocation of Energy Systems: A Theoretical Examination and an Agent-Based Model of Renewable Energy Systems

Lauf, Thomas 25 August 2017 (has links)
The question how a least-cost spatial allocation of sustainable electricity infrastructure may look like using different decision-making procedures (markets, different kinds of land-use and grid regulations) has not yet been analysed explicitly. We measure the sustainability of emerging energy landscapes providing power from renewable energy sources (RES) by an overall welfare function also comprising all kinds of space-related disutilities, i.e. spatial externalities - be they site-specific or related to the distance to a residential area (consumer centre). The presented agent-based model (ABM) concept aims at assessing different policy scenarios to govern the land-use for energetic purposes under the constraint of ensuring the electricity supply for a virtual landscape with RES. To derive optimal spatial allocation an agent-based modelling approach is implemented, which includes a virtual landscape, three settlements as demand centres and profit-oriented producers of renewable power. For the design of the electricity grid and the calculation of grid-related reinforcement costs a load-flow model is applied, being also able to map grid externalities during the RES expansion in space. The model allows RES producers to choose profit-maximising cells for plant installations until the given demand for power of the virtual landscape is met. Different policy scenarios allocate particular costs to agents (e.g. grid reinforcement costs, spatial externalities) or restrict the land-use with respect to ecological or social restraints. Furthermore, consumer centres have the possibility to follow own particular regional strategies, to increase their individual benefit. The overall efficiency of allocation (total cost level) as well as the distributional fairness (regional net costs) are evaluated for the policy scenarios and the regional strategies.
49

The Operational Strategy Optimization of Distributed Energy System Based on MATLAB : A case study in Northeast China / Optimering av driftsstrategi för distribuerade energisystem baserat på MATLAB : En fallstudie i nordöstra Kina

Han, Yujun January 2023 (has links)
China is the largest energy consumer worldwide, with a fast-growing rate. But the energy and environmental problems brought by its unbalanced energy structure and low energy efficiency restrict the sustainable development of China. The Distributed Energy System (DES) is one of the internationally recognized solutions to the problems. To enhance the implementation of the DES under China’s scenario, the thesis develops computational models for the Combined Cooling, Heat, and Power (CCHP) and Separated Cooling, Heat, and Power (SCHP) systems for a Micro Energy Grid in northeast China using MATLAB. The objective is to minimize the overall expenditure, energy use, and carbon emission equivalents. The results show that the CCHP system reduces 18.62% of the overall expenditure and 35.02% of the carbon emission equivalents than the SCHP system. The CCHP system has a promising prospect in China with better Greenhouse Gas emissions reduction and economic performance. / Kina är världens största energikonsument, med en snabb tillväxttakt. Men de energi- och miljöproblem som orsakas av den obalanserade energistrukturen och den låga energieffektiviteten begränsar Kinas hållbara utveckling. Distribuerade energisystem (DES) är en av de internationellt erkända lösningarna på dessa problem. För att förbättra implementeringen av DES enligt Kinas scenario utvecklar avhandlingen beräkningsmodeller för kombinerad kylning, värme och kraft (CCHP) och separerad kylning, värme och kraft (SCHP) för ett mikroenerginät i nordöstra Kina med hjälp av MATLAB. Målet är att minimera de totala kostnaderna, energianvändningen och koldioxidutsläppen. Resultaten visar att CCHP-systemet minskar de totala utgifterna med 18,62 % och koldioxidutsläppen med 35,02 % jämfört med SCHP-systemet. CCHP-systemet har lovande utsikter i Kina med bättre minskning av växthusgasutsläpp och ekonomisk prestanda.
50

CO-LOCATION OF WIND AND SOLAR POWER IN SOUTHERN SWEDEN

Dragasis, Michail Iakovos January 2023 (has links)
This paper examines the possibility of adding a photovoltaic(PV) power station to an already planned wind park in terms of profitability. At this time, southern Sweden’s grid is facing a number of challenges and is hurting economic development. Hybrid parks have showed to be able to tackle some of those challenges. This study has used a two-scaled methodology to analyse which solar PV size is the optimal to be co-located to the wind park of 24MW[Office1] . The results show that the 21MW size is the ideal one. In addition, to complement the findings, an analysis has been conducted to determine which battery size would be the optimal size to be added to the hybrid system. The results showed that a 1MW/1MWh battery storage would be the ideal size, however, it is possible that a 5MW/MWh battery storage might produce better results if peak shaving is included. All the scenarios in this study have been analysed in terms of IRR.

Page generated in 0.0602 seconds