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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.

Prospective of Tidal Energy

Patel, Keval January 2019 (has links)
No description available.

The impact of shadowing in photovoltaic systems and how to minimize it : An analysis with the PVsyst Software

Batista, Rúben January 2018 (has links)
No description available.

Analysis of Hybrid Offshore Floating Wind and Marine Power

kollappillai Murugan, Sai Varun January 2018 (has links)
Wind energy is a major part of renewable energy production. With fossil fuel depletion and climate change at the cusp, it is an absolute need to implement or evolve the current source or utilization of renewable energy. The wind has been dominating the onshore for many decades and offshore wind turbines are available at shallow depths.  To extract more wind energy source deep sea location is recommended. Also, in deep seas, ocean current energy is utilized very sparsely compared to the dominating wind and solar energy. So far no hybrid offshore horizontal axis and ocean current system are in existence. Based on the depth of the sea water the offshore floating structure is classified. Usually, for any floating structure stability is an apprehension. In an offshore floating structure, the damping with respect to the thrust force exerted on the wind turbine will affect the life of the wind turbine. During high wind speed, the angle of inclination would go up to about 4 degrees. The time required for the floating structure to come to rest may also be high. We present an analysis based on an existing floating structure which is a ballast stabilized the floating structure. In this paper, we add an additional submerged turbine and do a 2D analysis on the floating structure to find out whether the structure’s oscillation is well damped or not. We also discuss whether the weight of the submerged will influence the stability or by changing the radius of blades of the submerged turbine will affect the damping.

Energieffektivisering av fjärrvärme- och fjärrkylanätet på campus i Umeå : Energy efficiency of the district heating and cooling systems on campus in Umeå

Bäcklund, Johannes January 2018 (has links)
Detta examensarbete utfördes på uppdrag av Akademiska Hus som äger och förvaltar fastigheterna på campus i Umeå. Projektet bestod av att utifrån en övergripande bild på det interna fjärrvärme- och fjärrkylanätet på campus, ta fram alternativa utformningar på systemet i syfte om att göra det mer energieffektivt. Systemets interna fjärrvärme- och fjärrkylanät VP100 och KB100 växlar över värme och kyla från Umeå Energi som sedan distribueras vidare till fjärrvärme- och fjärrkylacentraler på campus. Några av centralerna har egenproduktion där returledningen från KB100 går till en värmepump som producerar både värme och kyla. Producerad värme används till att förvärma returledningen från uppvärmningssystemen från de byggnader som hör till respektive central. När behovet av värme är tillräckligt stort är systemet, tack vare värmepumparna, självförsörjande gällande kyla. Produktion sker alltså endast under de perioder då det finns behov i uppvärmningssystemen. Det leder till att systemet tvingas köpa både värme och kyla samtidigt under sommaren då behovet av kyla i stort sett är konstant under året. Två alternativa utformningar till det befintliga systemet har undersökts. Det första fallet har som syfte att reducera värmeförlusterna i VP100. Det andra fallet byggdes vidare på det första fallet med syftet att utvidga arbetsområdet för värme- och kylproduktionen i värmepumparna. Resultatet visar att det finns potential att mer än halvera värmeförlusterna i det befintliga VP100 och att produktionen av värme och kyla skulle kunna öka med 10 % respektive 6 %. Totalt skulle systemet kunna spara drygt 1,3 miljoner kWh per år genom en kombination av de två alternativa utformningarna. För att däremot få energibalans i systemet där det aldrig behöver köpas både värme och kyla samtidigt bör andra effektiviseringsåtgärder övervägas.

Lågtempererade uppvärmningssystem och dess potential i nybyggda och energieffektiva kontorshus : En studie i att använda returtemperatur från befintlig bebyggelse till uppvärmning

Gustafsson, Johan January 2018 (has links)
This master thesis examine how a low temperature radiator systemcan be implemented in a new built office and what effects this will have on the return temperature. One point in the system was logged and data was collected. A model was then developed in VIP-Energy to determine the heating demand for an office building which were compared to the supply. A cost analysis was also performed on different types of low temperature radiator systems. These were compared to a conventional radiator system with a supply temperature of 55°C and a return temperature of 45°C. A cost analysis was also done on whether to build energy efficient or not. The study shows a strong correlation between the heat demand and the time of day. The demand is low during office hours and high during nights and weekends with a peak demand of 70 kW. The low demand is due to the high amount of process energy an office uses. The point in the system can supply the heat demand during almost every hour of the year. For the few hours where there is a mismatch between supplied heat and demand, a shunt solution can supply the return water with primary heat. If the heat demand is scaled up with ten or twenty identical houses the point will be unable to supply enough power to cover the heat demand for more hours a year. The most cost-effective radiator system is Purmo Belize with a supply temperature of 40°C and a return temperature of 30°C. Purmo Belize has built in fans that can improve the heat supply to the room with up to 80 %. Compared to a conventional radiator the payback time is 9 years, with a return on investment of 12,8 percent and a net present value of 151 762 kr. A 40/30°C-system will lower the return temperature in the measured point with 0,4°C. For the whole system this means a reduced temperature of 0,00003°C if the total flow is 50 m3/s and the average return temperature is 50°C. From a strictly economic point of view, an extra energy efficient house will be beneficial if the extra cost is up to 5 000 000 kr or around 700 kr/m2 with a depreciation time of 25 years.

Simris lokala energisystem

Berkan, Yaroslav January 2018 (has links)
No description available.

Självförsörjande småskaliga ’off-grid’ nät, baserade på sol- och vindkraft i kombination med pumpkraftverk / Small scale selfsustained “off grid” systems based on solar and wind power combined with pumped hydro energy storage

olof, eriksson January 2018 (has links)
No description available.

Design av solcellsanläggning för strömförsörjning för Falkenbergs nya bibliotek

Sami Kasim, Ayvar January 2018 (has links)
Every life on the earth is addicted of the sun. The sun is clean and free energy source. In Sweden there is a long term goal for the global energy system with 100% renewable energy. To achieve this goal we need more efforts in a form of including solar cells. Solar cells has existed a long time on the markets, but in the recent years it has been more interesting in the world and it is mainly because the price has gone down, the quality has been better, the efficiency has been higher. Nowadays people are more interested to do something that is environmentally friendly and profitable. Because of the solar cells are applying good on the roofs and facades so the property companies have been more interested to place solar cells on their buildings. My project is about potential electricity generation for photovoltaic systems at the new library roof that will be built in Falkenberg. In my work I explain what a solar cell is, how it works, how many types are there and what kind of it is the most common, how solar systems work, how it is installed, what it takes to install solar cells, and what it provides for power. After I have tested different angles as solar modules are directed against, comparisons and calculations, the results of the design have shown that the roof of the library has good opportunities for mounting solar cells installations. The best angle was 27◦ to the south with azimuth 185◦. The conclusion of the work is that it is profitable to invest solar systems at the library's roofs. Repayment time is long but it is worth it, in this way Falkenberg’s government also makes an effort for the environment.

Application of a mathematical approach in modeling wind time series : A general survey of the Langevin method

Jalaei, Fatemeh January 2015 (has links)
Today, the great importance and benefits of renewable energies as a source of endless energy is obvious for all. Wind is recognized as one of the most stable and safest type of energy, due to ease of access as well as applying modern technical and scientific methods in order to its extraction. In this regard, much effort has been done in the developed societies to obtain knowledge besides getting access to new techniques in the exploitation of this unlimited wealth. Apart from the new aspects of the proposed research in wind area, the extraction operation requires specialists to advanced techniques and scientific research. The development of societies and their increasing necessity to energy resources have increased the importance of safe and clean renewable energy. This study investigates a technique to specify the power performance of the wind turbine directly from measured data which fluctuate with high frequency. This project is a review of a dynamical method for the specification of wind turbines' power curves. Considering the power output of a wind turbine in this study, the basic concept is to divide its dynamics into two components; a deterministic(relaxation) and a stochastic(noise) functions which are equivalent to the wind turbines' real behavior itself and the exterior wind turbulence. It specifically presents a procedure to estimate the reaction of the wind turbine as a machine to the wind speed dynamically. In this method, reconstruction of the coefficients from the measured data and extraction of the specification of the power output have been done. The main focus of this technique is on differential equations which are recognized as Langevin equations. As the consequence, it is shown; with this method we will be able to percept the conversion dynamics of wind turbines and get the power curves' results with high precision. The results demonstrate that power performance's specification is accurately reconstructed from the measured data by the quick estimation of the coefficients from data. Furthermore, the high accuracy and fast estimation of the power curves would be considered as preferences in this method.

Miljökrav på solceller : En utredning om koldioxidutsläpp från kristallina kiselsolceller / Environmental requirements on PV : A study on carbon dioxide emissions from crystalline silicon PV

Vanky, Kristin January 2018 (has links)
This master thesis is an investigation of environmental sustainability of photovoltaic (PV) modules. The purpose is to examine how purchasers of PV systems could put requirements on the modules so that their life-cycle carbon dioxide emissions reduces in the most effective way. The purpose is also to survey environmental third-party certifications for solar modules. Only mono- and multicrystalline silicon modules are considered. In the first part of the thesis, the carbon dioxide emissions from the manufacturing and transportation of different modules are calculated. Furthermore, the solar electricity production is simulated in the software PV syst. Modules with different peak power capacity, origins and manufactured with different techniques are compared. In part two, recycling techniques and regulations for management of end-of-life-modules are investigated. The number of end-of-life modules based on Solkompaniet Sverige AB´s historical installations are estimated and out of these, their potential economic value, based on two different recycling scenarios, is calculated. According to the results, monocrystalline modules cause higher emissions than equivalent multi-crystalline from the same manufacturer. Modules with the same peak power and silicon but with different origins and silicon manufactured with different technologies, produce about the same amount of electricity, but show a large variation in carbon dioxide emissions, mainly due the electricity consumption and the characteristics of the electrical mix used in the manufacturing process. The modules’ operating time in addition to pre requisite conditions for mounting are crucial for thee missions per produced kWh electricity, contrary the transports have very little effect on the total emissions. Carbon dioxide emissions could be reduced through re-usage of elements from recycled end-of lifemodules, particularly aluminum and silicon, but economic factors hinder this today, mainly due to too few end-of-life modules. Silveris the most expensive element in a module. The value of end-of-lifemodules will decrease by decreasing silver content, but overall increase due to increased waste volumes. The future economic value of end-of-life modules is hard to estimate, but could be crucial for the possibility to take advantage of the environmental benefit from treatment of end-of-life modules. In order to reduce carbon dioxide emissions from solar modules, requirements should be directed towards the module manufacturing process. This thesis emphasizes pre requisites expected to give lower emissions, hence modules that are more likely to cause lower environmental impact than others. To be able to develop specific requirements, more transparent and reliable energy consumption data is necessary. It exists very few, and no Swedish environmental certifications specifically designed for solar modules. The ranking list Solar Scorecard is not a certification but seems to be the most used in order to demonstrate manufacturers' environmental performances.

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