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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.
51

Evaluation of Energy Saving Measures in Ice Rinks

Zhang, Zhongyuan January 2013 (has links)
No description available.
52

Promising thermo-chemical conversion pathways for perennial crops

Tovar-Garza, Alejandro January 2013 (has links)
No description available.
53

Systemintegration av solcellsel och värmeåtervinning från spillvatten i flerbostadshus : Modellering av Evertherm SEW i kombination med solceller i tre svenska städer / Integrated system of photovoltaic electricity and heat extraction from wastewater in multi-family buildnings : Model of Evertherm SEW in combination with photovoltaic cells in three Swedish cities

Klippmark, Joel, Eriksson Sjögren, Ella January 2022 (has links)
För att minska samhällens påverkan på klimatet finns ett antal mål och strategier såväl på global som nationell nivå. En av dessa är Agenda 2030 där Mål 7: hållbar energi för alla bland annat syftar till att öka takten för energieffektiviseringar. En viktig sektor för energieffektiviseringar är byggnads- och bostadssektorn, då denna i dag står för 35 % av det globala energibehovet. För att minska energianvändningen och/eller inköpt energi i byggnader finns ett flertal möjliga åtgärder så som tilläggsisolering, uppgradering av värmeväxlare och installation av värmepump. En effektiviseringsåtgärd som tidigare inte varit vidare uppmärksammad men som kommer spela en stor roll för att nå effektiviseringsmål är värmeåtervinning från byggnaders spillvatten. Det finns olika tekniker för att ta vara på denna, i detta arbete undersöks tekniken Evertherm SEW som består av värmeväxlare, tankar och en värmepump och som tar vara på restvärmen. Då implementering av en värmepump leder till att behovet av inköpt el ökar undersöks även solceller, som kan reducera detta behov. I examensarbetet skapas en modell som undersöker de möjliga energi- och kostnadsbesparingar som erhålls vid implementation av solceller, Evertherm SEW samt dessa kombinerade i en systemlösning i tre svenska städer. Hur energipriser påverkar lönsamheten och vilken inverkan en storskalig implementering av Systemlösningen skulle ha på Sveriges el- och fjärrvärmesektor undersöks också. Resultaten visar att det geografiska läget för de tre systemen spelar roll då energi- och kostnadsbesparingarna varierar till följd av de lokala förutsättningar. För Solcellssystemet återfinns störst potential i Malmö till följd av hög solinstrålning och höga elpriser, medan lägst potential återfinns i Umeå. När Evertherm SEW studeras framgår att de höga elpriserna i Malmö i kombination med låga fjärrvärmepriser leder till att detta är staden med lägst potential för en implementering. I stället återfinns störst potential i Stockholm med liknande potential även i Umeå. Eftersom Systemlösningen är en sammankoppling av Solcellssystemet och Evertherm SEW är potentialen större i Malmö för denna än för ett fristående Evertherm SEW system, men fortfarande lägst då de tre städerna jämförs. Jämförs de tre olika systemen med varandra framgår det att Systemlösningen genererar de största årliga besparingarna, följt av Evertherm SEW och därefter Solcellssystemet. För återbetalningstiderna har Solcellssystemet de kortaste, följt av Systemlösningen och sedan Evertherm SEW. Lönsamheten för Evertherm SEW och Systemlösningen ökar, enligt resultatet, då det genomsnittliga fjärrvärmepriset ligger närmre eller är högre än det genomsnittliga elpriset som använts i beräkningarna. De genomförda modelleringarna visar också på att en storskalig implementering av Systemlösningen i Sverige skulle medföra ett reducerat årligt nettobehov av såväl fjärrvärme som el. Detta leder till att koldioxidutsläppen från el- och värmeproduktion i el- och fjärrvärmenäten kommer att minska på årsbasis. Studeras i stället påverkan på månadsbasis kommer elbehovet under vinterhalvåret öka medan överskottsel från solcellerna i Systemlösningen under sommarhalvåret skickas ut på nätet. Utifån resultaten rekommenderas den tekniska möjligheten att implementera Systemlösningen undersökas vidare då denna visar på förbättrad lönsamhet och minskat årligt behov av inköpt el och värme. / There are several strategies and goals in place to reduce societies impact on the climate, on a national level as well as a global. One of these goals is Agenda 2030 where Goal 7: Sustainable energy for all among others aims to increase the rate of implemented energy efficiency measures. One important sector for these measures is the building and housing sector, since this sector accounts for 35% of the global energy demand. There are several available measures to reduce the energy usage in buildings, such as additional insulation, upgraded heat exchangers and installation of heat pumps. One energy efficiency measure that has not previously been widely used, but that will play a part in reaching the energy efficiency targets, is heat recycling from the buildings wastewater flows. There are multiple technologies that try to harness this heat source, and one of these is examined in this master thesis. This technology is called Evertherm SEW and uses a system solution consisting of heat exchangers, buffer tanks and a heat pump to recycle the heat from the wastewater. Since the implementation of a heat pump increases electricity usage, the ability for photovoltaic (PV) cells to compensate for this is also being examined.  Through constructed models, the thesis examines the possible energy and cost savings obtained when implementing PV cells, Evertherm SEW and these combined in a system solution in three Swedish cities. How energy prices affect profitability and what impact a large-scale implementation of the system implementation would have on Sweden's electricity and district heating sector is also examined.  The results show that the geographical location of the three systems have an impact on the energy and cost savings which vary as a result of the local conditions. For the PV system, the greatest potential for implementation is found in Malmö due to high solar radiation and high electricity prices, while the lowest potential is found in Umeå. When Evertherm SEW is studied, it appears that the high electricity prices in Malmö in combination with low district heating prices lead to this being the city with the lowest potential for implementation. Instead, the greatest potential is found in Stockholm with similar potential in Umeå as well. Since the system implementation is an interconnection of the PV system and Evertherm SEW, the potential is greater in Malmö for the system implementation than for an independent Evertherm SEW system. Despite this, Malmö still has the lowest potential when all three cities are compared. If the three different systems are compared with each other, it appears that the System implementation generates the largest annual savings, followed by Evertherm SEW and then the PV system. For payback times, the PV system has the shortest, followed by the System implementation and then Evertherm SEW. Profitability for Evertherm SEW and the System implementation increases, according to the result, when the average district heating price is closer to or higher than the average electricity price used in the calculations. The constructed models also shows that a large-scale implementation of the System implementation in Sweden would lead to a reduced annual net demand for both district heating and electricity. This means that carbon dioxide emissions from electricity and heat production will be reduced on an annual basis. If the impact is studied on a monthly basis instead, the need for electricity will increase during the winter, while surplus electricity generated from the PV-system during the summer will be sent out on the grid.  Based on the results, it is recommended that the technical feasibility of the System implementation is investigated further as it is shown to improve profitability and reduce annual need for purchased electricity and heat.
54

The Efficiency of PV Modules: Expectations vs. Reality : A study of the Degradation of Solar Panels in Sweden

Forssblad, Julia, Lisper, Linnea, Stålnacke, Olivia, Tonell, Vera January 2022 (has links)
Solar energy is one of the fastest growing green energy sources worldwide today. Thepioneer modules in Sweden have been in use for quite some time. The aim of the reporthas been to examine how PV modules in Sweden have degraded a few years into theirlife cycle. This was accomplished using data from PV modules installed no later than2014. Data was collected from different arrays across the three regions set in the report,the southern, middle, and northern regions to examine how the efficiency changesdepending on location, size, and panel type. The efficiency over time was calculated usingthe solar energy received by the panels divided by the actual produced energy. The reportfound that the degradation of the panels was negative but a lot slower than what isexpected in warmer climates. This is thought to be due to the mild weather in the northernclimate and will result in the panels gaining a longer life cycle. The report did not find anydifference between rooftop modules and ground mounted modules, nor was there adifference between the monocrystalline and polycrystalline modules.
55

Energy efficient solutions within a manufacturing facility : Solutions​​ and suggestions to develop the energy efficiency at Wavin

Hermodsson, Fredrik, Ekstrand, Erik, Frostvik, Anna, Levin, Moa January 2022 (has links)
This bachelor's thesis examines four scenarios related to energy efficiency at the Wavin manufacturing facility in Eskilstuna, Sweden. The four scenarios are: (i) keeping the current production processes, (ii) replacing the electric boilers with biofuel boilers, (iii) installing solar cells and (iv) installing biofuel boilers and solar cells. Results show that the most favorable solution is to install biofuel boilers combined with 2500 m2 (462.5 kWp) solar cells, which yields total savings of 72 MSEK over a 25 year period compared to the current factory set up. Moreover, the results were more sensitive to fluctuations in electricity prices compared to biofuel prices, which indicate that the proposed solution makes the factory less dependent on fluctuating electricity prices.
56

Sustainable Energy Use in Agriculture : A Case Study of a Swedish Farm

Holmgren, Klara, Larsson, Ida, Mårlid, Tilde, Vangeli, Marius January 2022 (has links)
The aim of this study is to find possibilities for a more sustainable energy consumption inSwedish agriculture with Rådde Gård as a case farm. The study assesses the current situationand evaluates possible future measures that could help Rådde Gård become more sustainable.To find effective measures, a model of the energy system is constructed in MATLAB whichsimulates different scenarios.The study is delimited to the direct energy usage in the on-farm processes at Rådde Gård.Indirect energy usage as a result of off-farm processes and transportation is not included.The three main energy sources used at Rådde Gård was shown to be wooden pellets forheating, diesel for engines in vehicles and equipment, and electricity used for lighting, airconditioning, among other things.The total annual energy consumption at Rådde Gård was estimated at 443.1 MWh, of which115.2 MWh diesel, 184.7 MWh electricity, and 143.2 MWh wooden pellets. The fossil part of theenergy consumption at the farm is due to combustion engines in vehicles and equipment, andgenerates 31.5 tonnes of CO2 emissions annually. Two measures were suggested to remedythis. A fuel change to HVO or a change of engines from combustion to electric. At Rådde Gård,a fuel change to HVO would result in a reduction of CO2 emissions to 8.5 tonne per year. Since,electrification of agricultural vehicles is still in early stages, technologically, HVO could be seenas a transition step between fossil use and electrification.Other suggested measures were related to a change of heating system. Either by electrificationthrough an installation of an air-water heat pump, or through a biochar pyrolysis boiler which,although it generates less heat than conventional boilers, coproduces both heat and biochar.These two heating systems can also be combined.The study also found that roof-top solar panels could be an important future aspect of anelectrification of agriculture. For example, since harvesting and grain drying consumes muchenergy during the summer, the seasonal variation of solar production could be utilized.A sensitivity analysis was also performed which indicated that sensitive parameters were to alarger extent related to current electricity consumption and solar electricity production than tothe efficiencies of engines, boilers, and a heat pump.
57

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.
58

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.
59

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.
60

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

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

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