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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.

Energy consumption and thermal comfort: An assessment of the relevance of modelling tools and an analysis of the key causing factors of difference

EMELIEN, Timothée January 2014 (has links)
No description available.

Vindkraftpark på Öland : En förstudie omelproduktion och lönsamhet / Wind Power Plant on Öland : A feasibility study of electricity production and profitability

Giesecke, Oskar, Karlsson, Rikard January 2014 (has links)
För att öppna dörren till mer vindkraft i Sverige, krävs förstudier för områdesspecifika vindkraftparker. Detta projekt har som syfte att beräkna vilken elproduktion som kan förväntas hos en fiktiv vindkraftspark placerad på mellersta Öland. Därutöver görs en ekonomisk analys, vilken ska uppskatta parkens ekonomiska intäkt för den förväntade produktionen. Intäkter fås främst ur försäljning av elenergi på den nordiska elbörsen samt certifikatmarknaden. Om vindkraftsparken består av 3 vindturbiner med märkeffekten 3.3 MW och medelvindhastigheten stämmer överens med mätdata, förväntas parken ge en årlig elproduktion av 29,6 GWh. I den ekonomiska analysen har två fall resulterat till en minimal och en maximal ekonomisk intäkt. Det lägsta fallet visas ge en total intäkt av 291 Mkr. Det högsta fallet beräknades till 398 Mkr. Dessutom har fasta investeringskostnader och räntekostnader beräknats till 230 Mkr. Detta betyder att Vindkraftparken kommer få en vinst mellan 218 Mkr och 111 Mkr, exklusive kostander från nätförluster, drift och underhåll.

Development of a forest biomass supply model for a demonstration cogeneration project in Chile

Martínez Saperas, Verónica January 2010 (has links)
Although there is a great forest biomass potential in Chile and bioenergy could become a relevant energy industry in the country, its development has been prevented mainly by the lack of proper business models that can fit into the Chilean reality. Chilean forestry sector is characterized by small-scale ownership, a situation that requires the implementation of associative business models to provide a reliable supply for a cogeneration plant. Currently, small owners of biomass resources are not interested in developing bioenergy projects since they do not have enough feedstock to make a profitable project by their own. On the other hand, industries and project developers are not attracted to develop such projects because they do not have a secure and reliable long-term biomass supply. This is a vicious circle hard to break just leaving the market act by itself. The present project presents the development of a supply chain model for a small demonstration CHP plant located in Chiloé Island. The idea of this 2MWel installation is to promote these types of projects, that can provide heat and power to processing industries located nearby the biomass resource and replace conventional fuels currently used. According to calculations made, the amount of feedstock needed is available in a short distance from the energy demand point, which was ratified by a field trip made to the chosen plant site. The proposed business model to supply the plant was a cooperative model, based on the formation of a forest-owner cooperation. This model was chosen in order to empower small owners and provide them the appropriate management and technical tools to improve their income and quality of life by developing a sustainable and profitable business. There are several successful international experiences with this type of business model and also there are some small initiatives in the country that can be taken as a starting point for a novel industry in the energy sector. Since the Chilean energy matrix is strongly dominated by imported fossil fuels, it is only logical that the country should follow the path of developing its renewable energy sources and biomass is one of the most promising alternatives currently technically and economically feasible.

Guidelines of how to instrument, measure and evaluate refrigeration systems in supermarkets

Gimenez Gavarrell, Pau January 2011 (has links)
No description available.

Future Energy Supply, Simulations with Limited Resources

Benichou, Léo January 2011 (has links)
Many different organizations publish energy scenarios, from International Energy Agencyto oilproducers, but also independent academic institutions or experts. Each of these scenarios presentsome particularities. They may also reflect the interests of the institutions producing them. Ifpolicy makers are to safely rely on some scenarios for planning and analysis, there is clear needfor awareness rising regarding energy scenarios and, more generally, the future energy constraint. The Shift Project think tank addresses energy and climate change constraints in the modern world.The double degree thesis work presented in this report is the result of a five month internshipwith the Shift Project. The work was dedicated to, on the one hand, the implementation of an onlineinformation platform gathering long term historical data and energy scenarios and, on the otherhand, the development of an analytical framework for energy scenarios. These tools bring a betterunderstanding of published scenarios first by providing a unique overview of the whole ‘scenariolandscape’ allowing making comparison on relative scales and questioning their credibility. Theobjective is to increase transparency around the assumptions and meaning of the scenarios. Thetools produced will help decision makers by providing transparent material and operative filters inthe wide information base of energy scenarios. Ultimately, they help highlight the keyissuesinfluencing the global energy agenda.

Analysis of simultaneous cooling and heating in supermarket refrigeration systems

Marigny, Johan January 2011 (has links)
In this master thesis project, conventional supermarket refrigeration systems using R404A are compared with refrigeration system solutions using natural refrigerants such as carbon dioxide and ammonia. This systems analysis considers the behavior of those systems in floating condensing and heat recovery mode. System heating and cooling COP have been calculated by using computer simulation with the calculation software EES (Engineering Equation Solver). The impact of important parameters such as sub-cooling, external superheating and compressor discharge was also determined through the computer models.The estimation of the system annual energy consumptions shows that systems using natural refrigerant can compete with systems using artificial refrigerant by using heat recovery system such as heat pump cascade, heat pump cascade for sub-cooling, fixed pressure system and de-superheater. If the indirect emission of systems using natural refrigerant and artificial refrigerant is approximately similar, the direct emission for carbon dioxide systems and ammonia systems can be estimated to be 10000 times less important than R404A systems.Multi-unit refrigeration systems have also been studied in this project; it appears that in theory COP improvement of 10% is possible if the condensing temperature of each unit is controlled adequatelly. / B

Potential for biogas production fromslaughter houses residues in Bolivia : Systematic approach and solutions to problems related to biogas production at psychrophilic temperature

Tesfaye Tefera, Tadious January 2011 (has links)
Residues from slaughter houses offer an abundant resource in Bolivia. The residues can beused for biogas production with biofertilizer as a bi-product. These resources are, however,currently not being used. Instead, they are released in water systems, implying heavycontamination, e.g., on the Lake Titicaca in western Bolivia. Severe environmental effects areobserved in the lake and connected water systems. The residues from slaughter houses are animportant part of the problem. If the contamination continues, important environmental values willbe lost. Information around the resource is scarce, since no extensive inventory has been carried out. It isestimated that officially registered slaughter houses in the four major cities of Bolivia aloneproduce over 75 tons of organic residues per day. This flow of residues has increased since theworld market for animal fodder based on blood dropped significantly. In addition, there is littleexperience of biogas production in cold environments at that altitude, almost4000 meters over sea level. Production of biogas from waste is one of the most common methods to generate energy and at thesame time best waste reduction methods. Biogas production can be practiced favoring one theextremities, that is, either for the purpose of energy production or waste reduction. In this thesis, the focus is on waste reduction, that is the slaughter houseresidues. Nevertheless, the ultimate outcome is always to reduce as much waste as possible and, atthe same time, generate profitable energy. There are many technological and financial challenges that have to be addressed to see the completerealization of the biogas concept. Therefore, this master thesis focus on producing biogas fromresidues of slaughter houses in the greater area around Lake Titicaca and studies whichtechnological issues have to be solved. Furthermore, analyzing how the biogas segment can befurther developed in Bolivia according to the appropriate technology selection is alsoinvestigated.

Effekten av en ökad andelsolceller på Linköpingslokalnät : En konsekvensanalys av Linköpings solelsmålgenom identifiering av kritiska områden medhänsyn till svaga nät och troliga adopters

Edvardsson, Astrid, Lundkvist, Nils January 2021 (has links)
Antalet installerade solcellsanläggningar i Sverige har ökat exponentiellt de senaste åren och iLinköping har kommunen antagit ett solelprogram som innebär att lokalproducerad solkraftska stå för fem respektive 20 procent av kommunens totala elanvändning år 2025 och 2040.Linköpings solelprogram förväntas leda till ökade installationer av solcellsanläggningar både iform av solkraftsparker och decentraliserade solpaneler som installeras på byggnader. Dennastudie fokuserar på utmaningarna som följer av decentraliserad solelsproduktion.Syftet med studien är att undersöka vilka fastighetsägare som har drivkrafter, hinder ochegenskaper som kan användas för att identifiera geografiska områden där installationen avsolpaneler på byggnader förväntas bli hög i framtiden. Genom att kombinera dessa parametrarmed identifiering av svaga elnät utvecklas metoden områdessegmentering, för att identifieraområden i elnätet med potentiellt stora utmaningar kopplade till ökad andel solceller. Vidareanvändes områdessegmentering för att ta fram ett fallstudieområde i Tekniska verken iLinköping AB:s lågspänningsnät. Fallstudieområdet användes sedan för att jämföra trenätåtgärder: nätförstärkning, energilagring och curtailment. Åtgärderna kan hantera deutmaningar som uppstår på grund av solelens intermittenta och dyngsvarierande karaktär ochanalyserades utifrån nyttjandegrad av energi och ekonomisk lönsamhet.Resultatet visade att småhusägare är den enda typ av fastighetsägare vars parametrar kanidentifieras för att tillämpas i områdessegmentering. De viktigaste parametrarna är relateradetill goda ekonomiska förutsättningar eftersom de ekonomiska hindren visats vara viktiga attöverkomma. Dessutom är även parametrar kopplade till fysiska förutsättningar, samt antaletgrannar som installerat solpaneler, viktiga faktorer för småhusägare i beslutsprocessen attsjälva installera. Gällande åtgärderna har nätförstärkning högst nyttjandegrad av energi,medan curtailment har lägst nyttjandegrad men också den lägsta årliga kostnaden. Batterilagermåste överdimensioneras effektmässigt för att närma sig samma nyttjandegrad somnätförstärkning och är i dagsläget inte ett ekonomiskt försvarbart alternativ. Däremotförväntas batteripriserna fortsatt sjunka och lönsamheten ökar troligtvis om batterilagringkombineras med andra elnätstjänster. Slutsatsen är att i nuläget antas nätförstärkningfortfarande vara den bästa åtgärden som Tekniska verken i Linköping AB kan vidta menalternativa lösningar blir mer och mer konkurrenskraftiga. Ytterligare utvärderingar avbatterilagring eller annan typ av energilagring i kombination med curtailment rekommenderasdärför eftersom det sannolikt kommer bli lönsamt inom en överskådlig framtid. / The number of installed photovoltaic systems in Sweden has increased exponentially in recentyears and in Linköping the municipality has adopted a solar program, Solelprogrammet, whichmeans that locally produced solar power will account for five and 20 percent of themunicipality's total electricity use in 2025 and 2040. Linköping's solar program is expected tolead to increased installations of photovoltaic systems in the form of both large solar powerplants and decentralized solar panels installed on buildings. This study focuses on thechallenges posed by decentralized solar power production.The purpose of the study is to investigate which property owners that have driving forces,barriers and characteristics that can be used to identify geographical areas where the potentialfor large installations of solar panels on buildings is high. By combining these three types ofparameters with the identification of weak electricity grids, a method was developed to identifyareas in the electricity network with potentially major challenges linked to an increasedproportion of solar cells. Furthermore, this method was used to identify a case study area inTekniska verken in Linköping AB's low voltage grid. The case study area was then used tocompare three grid solutions: network reinforcement, energy storage and curtailment. Themeasures can handle the challenges that arise due to the sun's intermittent and diurnal natureand were analyzed based on the degree of utilization of energy and economic profitability.The results showed that single-family homeowners are the only type of property owner whoseparameters can be identified for application in the developed method. The most importantparameters are related to good economic conditions as the economic barriers have been shownto be important to overcome. In addition, parameters linked to physical conditions, as well asthe number of neighbors who have installed solar panels, are important factors for homeownersin the decision-making process to install themselves. Regarding the solutions, gridreinforcement has the highest degree of utilization of energy, while curtailment has the lowestdegree of utilization but also the lowest annual cost. Battery storage must be oversized interms of power to approach the same utilization rate as grid reinforcement and is currentlynot an economically feasible alternative. On the other hand, battery prices are expected tocontinuously fall, and the profitability is likely to increase if battery storage is combined withother grid services. The conclusion is that at present, network reinforcement is still assumedto be the best measure that Tekniska verken i Linköping AB can take, but alternative solutionsare becoming more and more competitive. Further evaluations of battery storage or other typesof energy storage in combination with curtailment are therefore recommended as it is likely tobe profitable in the foreseeable future.

A new energy model for the Lakshadweep islands : Change from a diesel-based model to a hybrid model with renewable energy systems considering the ecological fragility of the islands

Alcoverro Colom, Pau January 2019 (has links)
No description available.

Evaluating the onshore wind power potential of Gotland using the New European Wind Atlas

Arteaga Ossa, Andres January 2021 (has links)
The island of Gotland has played an important role in the history of wind energy in Sweden since the very beginning. In the past decade, the island reached the maximum intermittent wind power capacity that the local grid and the current connection to the mainland can safely manage without compromising the security of supply. There were plans to install a new submarine cable, but they were finally cancelled. Nevertheless, the Swedish Government has decided to start a pilot project to make Gotland the spearhead of the energy transition. Most likely, this means that a new wind power expansion will have to take place on the island. In that context, the present study aims to estimate the onshore wind power potential of Gotland based on the New European Wind Atlas released in 2019. The starting assumption is that the potential of the island is limited to the areas appointed of national interest for wind energy by the Swedish Energy Agency. Then, the wind power potential is estimated under three technological scenarios ranging from the wind turbines operating on the island to the wind turbines recently launched on the global market. The results show that Gotland has the potential to annually produce between 2.2 TWh and 2.7 TWh of additional energy from the available wind depending on the technology used. Comparisons with real production records showed that the wind speed time series from the wind atlas proved to be useful to accurately reproduce the production patterns of real wind turbines on the island when values were aggregated at a daily or higher time scale. Additionally, mean wind speed at 100 m and the parameters of the Weibull functions fitted to the wind speed distributions were mapped for the whole island. Mean wind speeds obtained from the New European Wind Atlas for the areas of national interest on Gotland were compared to the respective values from the Swedish Wind Atlas. It was found that the latter gives systematically higher values with an average difference of 0.4 m/s within the sample.

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