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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.
41

Heat Flux Measurement using Infrared Thermography : The development and validation of a novel measurement method

Westergren, Erik January 2017 (has links)
No description available.
42

Biocarbon production from biomass based energy plant forapplication in high-value materials

Söderberg, David January 2019 (has links)
Natural graphite, a type of carbon, is used in most battery driven electronic devices around the world as it serves as the anode in Li-ion batteries. Since 67\% of global production of graphite originates from a single country the EU has classified it as a critical raw material with a high supply risk. If graphite can be produced locally from biomass not only would it potentially make batteries cheaper it could be a huge boon to the Swedish bio industry. In this thesis carbonization of pure lignin is done through hydrothermal carbonization and slow pyrolysis with peak temperature of 900\degree C. The type of carbon needed for these applications involves a high degree of crystallization and large surface areas and pore volumes. Analysis of the samples was done through X-Ray Diffraction, Raman spectroscopy, CHNO- and specific surface analysis. Results show a D/G ratio of 0.85, full width half maximum (FWHM) values of 7.7, which points toward a hard carbon with nano crystalline graphite present in the samples. SSA results show a Brunauer–Emmett–Teller (BET) surface area of around 350 $m^2/g$ and CHNO show a carbon content of about 90\%. The results are promising for use as an anode in hard carbon sodium-ion batteries or for $CO_2$ separation. Techno-economical analysis show that integrated biocarbon production in a bio-ethanol plant is a much more profitable solution than selling the lignin as biofuel or burning it for electricity production.
43

Solenergi i Tranemo : En utvärdering av solenergins potential i Tranemooch andra mindre kommuner.

Sjögren, Pontus, Wåhlin, Henrik January 2015 (has links)
Runt om i världen ökar produktionen av elektricitet från solenergi och Sverige är inget undantag. Här uppnår däremot solelens andel av totala elproduktionen mindre änen promille. I denna rapport har vi därför utvärderathur mycket potentiell takyta som finns att tillgå i Tranemo kommun. För att evaluera detta har det gjorts en fältstudie tillsammans med samarbetspartnern Tranemo kommun där företag och kommunala byggnader undersökts. Därifrån har takytors area, lutning och väderstreckdokumenterats för att med vår egenkonstruerade beräkningsmodell uträknalämpligheten för platsen. I beräkningsmodellen behövs endast treindataför att kunna räkna ut ett ungefärligt värdepå solinstrålningen mot en vinklad yta. Dessaär platsens koordinater samt ytans lutning och vädersträck. För ett mer precist värde är molnighetsgrad nödvändigt för platsen. Vi har dokumentera en yta på 116000m2för solceller vilketkan utgöra 7 % av det årligaelbehovet i Tranemo, men endast en mindre delpå 46000 m2användbar ytaanser vi idag vara lämpliga. Det finns dock mycket mer yta att tillgåeftersom siffrorna endast är baserade påkommunala byggnader och företag.Delämpligaytorna kan bidra med en elproduktion på 6,74 GWh, motsvarande 3 % av Tranemos årliga elanvändning. Som kontrast har Sverige i dagsläget också en potential på ungefär 3 %. Kommunens potential är följaktligen näramedelvärdet för landet, vilket skulle påvisa goda möjligheterför solenergi.
44

Modellering och analys av sekundärvärmesystemet på Iggesunds bruk / Modeling and analysis of the secondary heating system at Iggesunds bruk

Bergsten, Daniel January 2015 (has links)
Iggesund Paperboard AB är ett företag inom Holmenkoncernen med verksamhet i Iggesund och årligen produceras över 300 000 ton kartong. För att minska användningen av fossila bränslen har företaget investerat i en ny sodapanna vilket har skapat nya förutsättningar i fabrikens sekundärvärmesystem som tar hand om fabrikens spillvärme. I detta projekt har möjligheterna att minska vatten- och energianvändningen i fabriken analyserats genom att studera fabrikens sekundärvärmesystem. Utifrån ritningar samt information från fabrikens loggsystem skapades en simuleringsmodell med modellverktyget Extendsim. Detta för att analysera hur hetvattenbehovet i sekundärvärmesystemet kan täckas när hetvattenproduktionen minskar från stripperkolonnen. I modellen undersöktes även den ökade fjärrvärmepotentialen i filtratvatten från blekerier och hetvattenöverskott då blekerierna moderniseras i fabriken. Projektet är ett examensarbete i civilingenjörsprogrammet i energiteknik på Umeå universitet, och har utförts under hösten 2014. Resultatet visar att den minskade hetvattenproduktionen från kondensorer vid stripperkolonn kan kompenseras med ökad hetvattenproduktion från kokerikylare samt varmvatten från rökgasskrubber då ånga från stripperkolonn istället används till lutförvärmning. Det primära ångbehovet minskar med 23 900 ton per år då ånga från stripperkolonn används till lutförvärmning. Detta leder till 5,17 MSEK i minskade kostnader för företaget med ett ångpris på 216 SEK/ton, och gör en investering i regleringsutrustning lönsam med en återbetalningstid på 0,9 månader. Investeringarna i och med modernisering av blekerierna har en liten påverkan på den totala råvattenanvändningen i sekundärvärmesystemet, dock minskar vattenanvändningen i blekerierna vilket ökar möjligheterna att använda sekundärvärme till andra områden. När samtliga åtgärder i blekeriet är genomförda är fjärrvärmepotentialen i filtratvatten och hetvattenöverskott 21 MW och kan värma en fjärrvärmeprimär upp till 68 °C.
45

Optimization of a grid connected residential battery storage system in Sweden : Home Energy Management System Approach

Gomez, Fabrizio January 2018 (has links)
The market for energy production has experienced relevant changes to reach more sustainable characteristics, during the last two decades. In this context, residential photovoltaic (PV) system has gained popularity as a practical and profitable alternative to complement the electric supply from the grid. In the same line, the seasonal and variable nature of PV supply generates an interest in BESS-battery energy storage systems.The aim with this thesis is to investigate HEMS-home energy management system for a residential electricity production using PV and storage in Sweden. HEMS allows residential customer and producer to sell or buy energy to minimize the final electricity bill. The capacityof BESS and the scheduling are optimized by using a proposed algorithm. Results gained indicate that factors such as household electricity demand and allocation during the day, electricity price, and tariff scheme are the critical variables to consider in the design of the BESS system. Optimal battery capacities obtained are within the range of available battery market stock-sizes. However, several of the standard battery capacities of the leading manufacturers are oversized for this case. For Swedish context, a BESS installation cost below 270 €/kWh generates saving on the annual electricity bill of having BESS in comparison with not using BESS. In addition, the daily charge of EV, electric vehicle, was studied to see if a higher demand for household electricity could generate an optimal capacity and higher savings. / Marknaden för energiproduktionhar under de senaste två decenniernagenomgått förändringar för att bli mer hållbar. I detta sammanhang har solcell-system eller photovoltaic, PVför elproduktion i bostäder blivit ett praktiskt och lönsamt alternativ för att komplettera elförsörjning från elnätet. Solcellernas produktion är dock säsongsbetonadoch varierar även över dygnet varför system för lagring av el i batterier s.k. BESS blir intressant.Syftet med denna uppsatsär att undersöka HEMS, ett hushålls system för hantering avel-generering med solcelleroch batterilagring i Sverige. HEMS tillåter bostadskunder och producent att sälja ochköpa elför att minimera den slutliga elräkningen. Kapaciteten för BESSoch schemaläggning optimeras med hjälp av en föreslagen algoritm. De uppnådda resultaten tyder på att faktorer som efterfrågan på hushållsel och fördelning under dagen, elpriset och systemen för taxaär de kritiska variablernaatt beakta vid utformningen av BESS. Optimal batterikapacitet som uppnåtts ligger inom området för, på marknaden, tillgängliga batteristorlekar. Flera av de vanligaste batteriernas kapacitet,hos de ledande tillverkarna,är dock överdimensionerade. För svenska sammanhang genererar en BESS-installationskostnad under 270 € / kWh besparingar på den årliga elräkningen i jämförelse med att inte använda BESS. Som tillägg studerades daglig laddning av en elbil för att se om ett större elbehov kunde generera en mer optimal kapacitet och än större besparinga
46

Ökad matarvattentemperatur vid biopannan Smurfit Kappa Piteå : Increased feedwater temperature at biomass boiler Smurfit Kappa Piteå

Hedström, Anton January 2018 (has links)
Smurfit Kappa Piteå is the largest kraftliner producer in Europe. At the mill they have five different steam producers and one of those is the biomass boiler, which is a steam boiler producing overheated steam at 120 bar and 520C. The purpose of this report is to investigate the possibilities to increase the feedwater temperature from today’s 180C to 210C. The consequences on the system are depending on the temperature in the different process stages and the process temperatures are therefore calculated via a method named The NTU-method which is a suitable method to analyze the heat transfer within an object when the ingoing and outgoing temperature are unknown. The feedwater is preheated with a heat exchanger that is heating the feedwater from 130C to 180C using steam with a pressure of 11 Bar. To increase the temperature to the desired  the approach is to install a complementary feedwater heater that uses steam with a pressure of 27 Bar. The new heater is supposed to heat the feedwater from 180C to 210C while the old heater takes the temperature from 130C to 180C. If the old heat exchanger approaches its end of life span it may have to be replaced with a new one with the same design data. One way to fulfill the required heating is to install one feedwater heater that takes the temperature from 130C to 180C using steam with a pressure of 11 Bar and in the next step install the second feedwater heater that takes the temperature from 180C to 210C using steam with a pressure of 27 Bar. There are two alternatives to installation of complementing high pressure heat exchanger. First alternative A is to install the second feedwater heat exchanger between the economizer and the steam dome. Second alternative B is to install the second feedwater heat exchanger between the already existent heat exchanger and the economizer. The consequence of the installation B is an increased energy loss due to the combustion gases while the consequence of installation A does not involve any increase in energy losses. Therefore, alternative A is wiser. However, whatever alternative that is chosen problem will arise since the temperature margin between the steam dome’s saturation temperature and incoming feedwater temperature needs to be at least 25C. This means that the largest possible pre-warming between the boiler’s workload 50-110% is 21C which not do apply to the whole interval. So, as it seems, the utilization of a second feedwater heat exchanger is not applicable over the whole interval of workloads. The increased feedwater temperature come with other consequences on the system. The whole system will be changed due to the increased temperature and it will affect the details. Some of the pipes must be replaced with new ones that fulfills the restrictions accompanying higher process temperatures. The purpose of the increased feedwater temperature is to increase the mass flow steam to the turbine. From calculations and the extraction-steam-consumption graph the increasing net power outcome from the turbine will increase with about 7.5% due to the increasing feedwater temperature. This will make the turbine produce even more electric energy and generate a bigger income to the factory. The investment cost is in total approximately 25MSEK, including replacing the old feedwater heater with a new one and installing a second feedwater heater. With a payback time of eight years and a life span of ten years it is necessary to question the economic potential of the installation. It provides a hint of the potential of the project. However, one should know that all numbers in this report are estimated from rough calculations.
47

Climate change mitigation through CDM : bioenergy technology and energy efficiency in the steel industry

Wang, Chuan January 2005 (has links)
Climate change is one of the most significant challenges to sustainable development facing the international community. Increased attention has been given by industries and governments from both industrialized and developing countries to reduce greenhouse gas (GHG) emissions through the clean development mechanism (CDM), one of the Kyoto Protocol's (KP) flexible mechanisms. China is the biggest developing country in the world. The energy demands in China are increasing quickly with its rapid economic growth. However, low energy efficiency and coal-dominated energy make China the world's second largest CO2 emitter behind the United States. Sweden, an industrialized country with high-energy efficiency and a good renewable energy system, shows its leadership in international cooperation and competence on the climate change issues. Sweden has already declared its desire to contribute to making KP's CDM work and become an effective instrument in the work on international climate change mitigation. It is of great interest to investigate the possibilities and the potential of GHG emission reduction through CDM. The objective of the work, considering the mitigating greenhouse gases in a global perspective, is to study how to introduce CDM with technology transfer between Sweden and China. This study provides illustrative examples of opportunities and benefits as well as revealing the problems associated with this mechanism. Two research areas, i.e. bioenergy technology and energy efficiency in the steel industry, are studied in this thesis. Regarding bioenergy technology, with consideration of technology status and biomass resource differences between Sweden and China, this study explores the potential and benefits of implementing Swedish advanced bioenergy technologies in China. A case study further shows that it is possible to produce and utilize wood pellets in China by using Swedish technology under CDM. As for the energy efficiency in the steel industry, an optimization model was developed to simulate CO2 emissions. The modeling results show that CO2 could be reduced at a low cost by implementing CDM projects between Swedish and Chinese steel plants. / <p>Godkänd; 2005; 20070108 (haneit)</p>
48

Batterier i elnätet : Analys för användning vid driftstörning / Batteries in the electric grid : Analysis for usabilty during power outages

Malmqvist, Simon January 2018 (has links)
The energy consumption in Sweden has risen remarkably over the last 40 years and the society is more and more dependent on electricity to maintain socially important functions. Authorities, grid-owners and consumers are increasing their demands for a more secure energy delivery. Skellefteå Kraft is doing continuous investments in this area and its focus is to get the electric grid durable and weather resistant. It is, however, not possible to this is within the same year due to technical- and economic reasons which is why there ́s a need for an effective preventive maintenance solution. Batteries have seen a huge breakthrough thanks to the electric car and increasing demand to store renewable energy. Hopefully batteries are powerful enough to be a viable solution as backup power when a power failure occurs which is what this project have been investigating. This project consists of a literature study regarding the current battery technology that ́s in use today but also the future technologies that are under development and expects to be commercially available within the next 15 years. The project has also done a theoretical set-up to see if today ́s batteries are capable of providing enough power to a normal size house over at least 12 hours while they also are light enough to transport by one or two technicians. This set-up includes two different inverters and four battery alternatives that are compared to each other. The results show that it ́s theoretically possible to use smaller batteries to provide enough power when connected to each other to form a battery bank. It does however require between 20 to 32 batteries to reach enough capacity which also results in weights up to 700 kg and costs up to 500 000 SEK in total. Luckily experts ́ analysis and prognostics are positive and a potential investment in five years might be reasonable. A comparable battery bank in five years might cost 70 % less based on price reductions the past five years and new technology might even reduce weight and costs by 80 % in less than 15 years. If one wants to be prepared for a future investment a future project or degree project would be to do a small-scale prototype to evaluate the batteries real performance in the field.
49

Effektivisering genom rengöring av kylbatterier och avgasning av köldbäraren / Power reduction by clening the cooling coils and degassing of the coolant in stores

Ekeroth, Jesper January 2016 (has links)
No description available.
50

Energikartläggning av Benzeliusskolan : Med investeringskalkyl för installation av bergvärme

Johansson, Alexander January 2018 (has links)
This thesis includes an energy survey of a school in Luleå called Benzeliusskolan and was carried out on behalf of the municipality of Luleå. Benzeliusskolan is currently heated with electric radiators and the thesis contains an investment calculation for the installation of a geothermal heating system. Calculations have been made to determine Benzeliusskolans theoretical heat demand. A survey of current electricity usage for heating has also been carried out for cost comparisons.   The result of the thesis is following: • The theoretical heat demand for all buildings is 251 212 kWh per year. Transmission losses amount to 228 257 kWh and heat losses through infiltration amount to 34 646 kWh per year. The heat requirement for ventilation was calculated to 58 995 kWh. Heat input of 70 687 kWh takes place every year from internal heat and solar energy.   • Mapping current consumption resulted in that current usage is 257 952 kWh of electricity for heating and 12 684 kWh of electricity for tap water per year.   • The power requirement for all buildings, including waterborne heating batteries in all ventilation systems, was calculated to 146 kW.   • A proposal for a geothermal heating system with a main central in house B where heat pumps are placed and heat transport to the other buildings, houses A and C, takes place through isolated culverts. The cost has been estimated at approximately 2 200 000 SEK through quotes and standard costs. The cost includes geothermal heat pumps, waterborne heating batteries for ventilation systems, drilling, radiators, installation costs and culverts between the buildings. The cost is based on an internal rate of 2% and an expected life span of 20 years.   • The investment in a geothermal system results in a reduction in electricity consumption for heating and tap water of 68.8%, 186 275 kWh per year. The investment had resulted in a cost saving of approximately 113 000 SEK per year during the estimated 20-year life span of the heat pump. Break-even occurs after about 19 years and 7 months and the total savings after 20 years amount to 52 000 SEK.

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