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  • 1.
    Abrahamsson, Curt Johan David
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Pérez-Loya, Jesús José
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Fregelius, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Evestedt, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bladh, Johan
    Lundin, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Magnetic thrust bearing for a 10 MW hydropower generator with a Kaplan turbine2018Conference paper (Refereed)
  • 2.
    Abrahamsson, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Bachofner Gran, Clara
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    de Afonseca, Ana
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Eriksson, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Kalla, Christelle
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Lindqvist, Sandra
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Livscykelanalys av förbrukningsvaror: En studie för minskad klimatpåverkan inom Landstinget i Uppsala län2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Landstinget i Uppsala län (LUL) presenterade år 2014 ett miljöprogram med målet att minskasin klimatpåverkan inom bland annat transport, energi och förbrukningsmaterial. Syftet meddenna studie var att undersöka möjligheten för LUL att minska sina utsläpp av växthusgasergenom att välja mer miljövänliga varianter av två välanvända förbrukningsvaror inom vården:operationsset och tvättlappar. Detta utfördes genom att tillämpa metoden livscykelanalys(LCA), där tre varianter av operationsset, två sorters tvättlappar samt ett jämförbartavtorkningspapper följdes ”från vaggan till graven”.Studiens resultat skulle besvara frågan om vilken produkt inom de två användningsområdenasom avgav minst växthusgaser i form av koldioxid, metan samt lustgas under en livscykel, föratt uppfylla samma funktion inom avdelningarna operation samt geriatrik. Resultatet skullepresenteras i enheten koldioxidekvivalenter (eCO2). Dessutom identifieradesförbrukningsvarorna som medförde de minsta årsförbrukningskostnaderna för LUL.Operationsseten som undersöktes bestod av polylaktid (PLA), polypropen (PP) samt viskos.Avtorkningspappret bestod av pappersmassa och tvättlapparna bestod bland annat av viskossamt skumplast. Studien avgränsades till att inkludera växthusgasutsläpp från tillverkning avråmaterial, tillverkning av förpackningsmaterial, transporter samt förbränning.Efter utförd LCA kunde det observeras att en årsförbrukning av operationssetet i PLA släppteut minst växthusgaser med cirka 11 100 kg eCO2 per år, operationssetet i PP släppte ut mestmed 25 100 kg eCO2 per år och operationssetet i viskos bidrog med 20 300 kg eCO2 per år. Enårsförbrukning av avtorkningspappret bidrog med minst växthusgasutsläpp med 67,1 kg eCO2per år, medan tvättlappen i viskos släppte ut 134 kg eCO2 per år och tvättlappen i skumplastbidrog med det största utsläppsvärdet på 1 150 kg eCO2 per år.En årsförbrukning av båda operationsseten i PLA och PP kostade cirka 127 000 kr medansamma mängd av operationssetet i viskos ungefär kostade 125 000 kr. Avtorkningspappretkostade 4 790 kr för en årsförbrukning, tvättlappen i viskos kostade 21 000 kr och tvättlappeni skumplast kostade 19 800 kr.Resultatet från denna studie tydde på att LUL skulle kunna minska sin klimatpåverkan frånförbrukningsmaterial genom att upphandla operationssetet i PLA samt avtorkningspappretistället för de alternativen som används i dagsläget. Det finns en osäkerhet i resultatet då flertaletantaganden gjordes i brist på tillgänglig information. Resultatet anses dock ge en rimlig bild avmiljöpåverkan från produkterna då de minst klimatpåverkande förbrukningsvarorna till stor delutgjordes av förnyelsebart material.

  • 3.
    Achour, Nemer
    Sveriges lantbruksuniversitet.
    Evaluating energy efficiency and emissions of charred biomass used as a fuel for household cooking in rural Kenya2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In sub-Saharan Africa a large share of the energy use utilize biomass as a fuel. In some

    countries more than 90 percent of the energy use is biomass. This energy is primarily used for

    cooking, heating and drying. Cooking food on an open fire or using a traditional stove will

    combust the firewood inefficiently and leads to pollution in the form of particulate matter,

    carbon monoxide and other hazardous pollutants. Indoor pollution has serious health effects

    and especially women and children are affected by this since they spend more time in the

    kitchens compared to men.

    More efficient combustion would lead to less harmful pollution to women and children in

    these rural areas. There are different kinds of stoves on the market and one of them is the

    gasifier stove which allows the biomass to go through pyrolysis in a separate step before

    complete combustion. If the charred biomass is harvested before complete combustion it can

    be saved for later use. This stove will result in cleaner and more energy efficient combustion

    compared to the traditional 3-stone-fire.

    The aim of this study has been to evaluate the charred biomass harvested from this gasifier

    stove in terms of energy use efficiency, emissions and cooking time. The charred biomass was

    compared to conventional charcoal bought at the local market. The charred biomass

    investigated is charred Grevillea prunings from the

    Grevillea Robusta tree, charred coconut

    husks (

    Cocos nucifera) and charred maize cobs (Zea mays). They were tested by cooking a

    meal consisting of two dishes at five different households for different kinds of charred

    biomass and conventional charcoal as a reference.

    Using charred Grevillea prunings gives an energy saving up to 31 percent while charred

    coconut husks gives up to 11 percent energy saved compared to the 3-stone-fire. Charred

    maize cobs was only up to 2 percent more energy efficient than conventional charcoal due to

    its low energy density and fast burning rate. In most cases there was no significant difference

    between the emissions of the different charred fuel types. Only charred maize cobs resulted in

    significantly higher emissions than the other fuels. Household B deviated from the others

    households and had higher emissions. In conclusion the different types of charred biomass are

    good fuels for cooking. Charred maize cobs are less valuable since they require a higher rate

    of refilling of fuel during cooking and do not result in better energy use efficiency compared

    to conventional charcoal.

    There were no significant differences between the different types of charred biomass and

    conventional charcoal in emissions except for a few cases where charred maize cobs had a

    slightly higher level of emission compared to the others. CO

    2- levels were so low that there

    was no risk of harmful concentrations in any way. PM

    2.5-emissions levels were safe, but the

    CO-emissions levels for charred maize cobs were close to levels were symptoms might show.

  • 4.
    Adolfsson, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Characterization of combinatorial Cu2ZnSnS4 thin films2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The kesterite Cu2ZnSnS4 (CZTS) is considered as a possible absorber layer in future photovoltaic (PV) applications. The abundance of its constituent elements along with the material being non-toxic and having a direct band gap of around 1.5 eV make it an attractive material for solar cell applications. So far, cells with an efficiency of 12.6 % have been achieved. The limiting factor is the finished cells' open circuit voltage (VOC) deficit which has been attributed to structural defects in the material. Problems with sustaining a sulfur-enriched atmosphere during the annealing step of material production have been observed, and are thought to be partially responsible for the high density of structural defects. Elemental sulfur is commonly used for inducing a sulfur-enriched atmosphere in the anneal. In this study, four combinatorial and polycrystalline CZTS thin films were prepared and annealed in different conditions with regards to time, sulfur source and amount. The samples were characterized using energy dispersive-, Raman- and photoluminescence spectroscopy. The effect of the anneal on the different composition regions were analyzed and secondary phases were identified. Introducing CuS as the sulfur source during the anneal reduced the decomposition of the CZTS phase, and lowered the density of the defect complex [ZnCu + CuZn], while enlarging the single phase region. Strictly and highly Sn-rich compositions of CZTS was observed to yield both high cation order and photoluminescence intensity, and a link between the two parameters was observed.

  • 5.
    Ahlberg, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Georges, Elza
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Norlén, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    The potential of hemp buildings in different climates: A comparison between a common passive house and the hempcrete building system2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this bachelor thesis was to study the potential of hemp buildings in different climates. The report examines and models two different energy efficient building concepts – the more common passive house and the environmental friendly hempcrete building system. These two buildings thermal performances were then simulated and compared in different climates followed by a brief discussion about their economic and environmental impact.

    The simulation was performed with the energy calculating program VIP-energy v 2.1.1 with the two models located in Kiruna, Sundsvall, Malmo, Berlin and Rome to represent the different climates. Simulations for different wall sizes and a sensitivity analysis of some significant parameters were also made.

    The hempcrete building system showed to have a thermal performance similar to that of passive houses in more southern climates. In the north of Sweden however the hempcrete building required up to 20 % more energy than the passive house to maintain comfortable indoor temperatures. This deficit could be compensated for with hemp fibre insulation to augment the building envelope and U-value. Furthermore the hygrothermal material properties that were not included in the simulation can be expected to have a significant positive impact on hemp buildings relative thermal performance.

    With a passive house thermal performance, a healthy indoor environment and an economically viable and environmental friendly production process hemp building demonstrated great potential in all the fields studied.

  • 6.
    Ahlvin, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Arriaga, Yasmine
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Bauman, Elise
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Berglund, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Magnusson, Clara
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Wiklund, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Energiomställning Gotland: Alternativ för att nå ett förnybart energisystem2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Sammanfattning

    Syftet med denna studie är att i åtta scenarier konkretisera hur Gotland skulle kunna ställa om till en förnybar energiförsörjning. Detta ska visa vägen för hela Sveriges omställning till förnybar energi 2040. Studien ska tjäna som en första orientering av vad fortsatt forskning kan inriktas på. Metoden var främst litteraturstudie samt modellering och beräkningar utifrån representativa exempel. Bedöm- ning av alternativ gjordes utifrån de övergripande kriterierna hållbarhet, resurseffektivitet och realis- tisk potential. Som begränsning utgick studien från åtta scenarion med olika förutsättningar och olika fokus. Tidsramen var fram till 2030.

    Scenario 1 - Transport: I scenario 1 var fokus att göra transportsektorn förnybar. Biogas och el från vind- kraft ansågs vara de energikällor som bäst ersätter de fossila bränslena. Import av biodiesel bedömdes även nödvändig, framför allt till tung transport. Utmaningen ligger främst i den omfattande omställ- ningen som krävs av fordonsflottan.

    Scenario 2 - Industri: I scenario 2 fokuserades endast på industrins omställning till förnybar energi. Framför allt cementproducenten Cementa använder en stor andel av Gotlands energi. Alternativet med störst potential, och som bör prioriteras för fortsatta studier, ansågs vara att att elektrifiera Ce- menta.

    Scenario 3 - Bioenergi: I scenario 3 skulle bioenergi användas för att ersätta fossila bränslen, samtidigt som Gotland var självförsörjande på livsmedel. Industrin bortsågs ifrån. De två intressena visade sig vara förenliga.

    Scenario 4, 5 och 6 - Reglering: Scenario 4, 5 och 6 fokuserar alla på olika typer av energilagring och reglering. Detta är nödvändigt i ett energisystem som till stor del bygger på vindkraft och solenergi. Batteriparker, tryckluft, pumpkraft och vätgas studerades som möjliga lagringsmetoder. Främst bat- terier i kombination med vätgas ansågs ha potential på Gotland. Fortsatt breda studier krävs dock.

    Scenario 7 - Ingen kabel: Idag finns en kabel mellan Gotland och fastlandet för import och export av elektricitet. I scenario 7 kan den kabeln inte användas. Stor utbyggnad av vindkraften krävs då, spe- ciellt havsbaserad. För att lättare reglera energin föreslogs att Gotland delas in i mindre system.

    Scenario 8 - Energiplan 2020: Region Gotland har satt upp mål för energisystemet år 2020 i Energiplan 2020. I scenario 8 studerades hur energisystemet skulle kunna se ut om målen uppfylldes. Stora för- ändringar från dagens energisystem skulle krävas.

    Slutsatsen av studien var att fortsatta studier främst ska riktas mot möjliga lagringstekniker, indu- strins energiförsörjning samt samhällets inställning till en energiomställning. Lagringstekniker är en förutsättning för den storskaliga utbyggnad av vindkraft som är nödvändig och som finns potential för. Grundläggande för att nå ett förnybart energisystem är hela samhällets delaktighet. Att kartlägga allmänhetens drivkrafter och motsättningar är därför viktigt.

  • 7.
    Aldahan, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Svensson Grape, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Beräkning av kostnader för lågaktiv kärnavfallshantering2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The surtax in Sweden, which exclusively applies for nuclear power plants, in conjunction with low electricity prices, has forced Swedish nuclear power plants to minimize their expenses.

    At Oskarshamn power plant, estimation of cost, associated with low-level nuclear waste management has been conducted several years ago, but with lacking knowledge about how the calculations were performed. Therefore, the purpose of this project was to establish an independent cost estimation for compactible and non-compactible, low level and medium level nuclear waste. Cost estimates for free released low-level nuclear waste was also performed.

    By analyzing average economic figures from year 2014-2015 and visits on-site, an excel-based calculation template was accomplished. During the on-site studies, several visits to the low-level nuclear waste management facilities at Oskarshamn power plant were made, in order to get an overview of how the handling process works.

    By following the staff around, it was possible to estimate some of the time durations for the different parts in the handling process for compactible lowlevel nuclear waste, that were used in the calculations.

    The price for compactible low-level nuclear waste was calculated to 6,72 - 6,97 kr/kg, depending on the activity level. The non-compactible low-level nuclear waste price was found to vary between 4 – 48 kr/kg.

    The large fluctuations are due to different activity levels and associated additional costs in handling, measuring, final deposition etc.

    For both compactible and non-compactible nuclear waste, the storage cost is a factor that dominates the total cost and that could be minimized. Based on the analysis presented in this work, the cost can be decreased by reducing the storage time and/or store the nuclear waste in a more space efficient way.

    The cost estimate for free released material is low (5,94 – 8,74 kr/kg), which concludes that Oskarshamn power plant may profit from free releasing as much material as possible, due to the fact that it is highly profitable to recycle metals.

  • 8.
    Alenius, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Analys och vidareutveckling av marknadsstyrd effekttariff inom eldistribution: En fallstudie av Sandviken Energi Elnät AB:s effekttariff2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis evaluates the incentives of a newly implemented market controlled network tariff by analyzing consumption data and constructing a time-differentiated debiting model. The tariff was implemented by Sandviken Energi Elnät AB and the thesis evaluates its customers consumption data compared to data provided by Sundsvall Elnät AB. The differences in data is evaluated by statistical tests of Students t-test, Bayesian t-test and χ2-test with the result that no statistically significant change in user pattern can be found and thus an elucidation of the incentives must be made in the form of a hourly time-differentiated debating model. The thesis also evaluates the cost incentives of the model compared to spot prices where it is shown that the tariff model can benefit much from the spot prices hourly incentives in its hourly time-differentiated model. Five time-differentiated models were constructed and presented where three uses a color coding scheme. The conclusion is that a color coded time-differentiated tariff should give the costumers clear and cost-effective incentives.

  • 9. Alev, Ullar
    et al.
    Eskola, Lari
    Arumägi, Endrik
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Arts, Department of Art History.
    Jokisalo, Juha
    Donarelli, Anna
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Arts, Department of Art History.
    Siren, Kai
    Broström, Tor
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Arts, Department of Art History.
    Kalamees, Tango
    Renovation alternatives to improve energy performance of historic rural houses in the Baltic Sea region2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 77, p. 58-66Article in journal (Refereed)
    Abstract [en]

    This paper analyses renovation alternatives to improve energy performance of historic rural houses in three countries (Estonia, Finland, Sweden) in the Baltic Sea region (cold climate). The study was conducted by a combination of field measurements and simulations. Indoor climate, typical houses and structures as well as the current condition and need for renovation were determined by field measurements. Based on field measurements, indoor climate and energy simulation models were validated and used to calculate energy use for different renovation measures. Energy renovation packages were calculated for different scenarios (minimal influence on the appearance of the house, improvement of thermal comfort, improvement of building service systems) for different energy saving levels. The analysis showed that the improvement of building service systems and the energy source holds the largest energy saving potential. The building envelope of old rural houses needs improvement also due to high thermal transmittance and air leakage. The insulation of the external wall has the largest single energy saving potential of the building's envelope. The results show how energy savings depend on energy saving targets, typology of the building, thermal transmittance of original structures, and building service systems. (C) 2014 Elsevier B.V. All rights reserved.

  • 10. Alexandrou, E.
    et al.
    Katsaros, M.
    Aravantinos, D.
    Axarli, K.
    Chatzidimitriou, A.
    Gotoudis, A.
    Theodosiou, Th.
    Tsikaloudaki, K.
    Technical guidelines for energy efficiency interventions in buildings constructed before 1955 in Greece2018In: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, p. 294-301Conference paper (Refereed)
  • 11.
    Alfimov, Vasily
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Accelerator Mass Spectrometry of 36Cl and 129I: Analytical Aspects and Applications2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Two long-lived halogen radionuclides (36Cl, T1/2 = 301 kyr, and 129I, T1/2 = 15.7 Myr) have been studied by means of Accelerator Mass Spectrometry (AMS) at the Uppsala Tandem Laboratory.

    The 36Cl measurements in natural samples using a medium-sized tandem accelerator (~1 MeV/amu) have been considered. A gas-filled magnetic spectrometer (GFM) was proposed for the separation of 36Cl from its isobar, 36S. Semi-empirical Monte-Carlo ion optical calculations were conducted to define optimal conditions for separating 36Cl and 36S. A 180° GFM was constructed and installed at the dedicated AMS beam line.

    129I has been measured in waters from the Arctic and North Atlantic Oceans. Most of the 129I currently present in the Earth's surface environment can be traced back to liquid and gaseous releases from the nuclear reprocessing facilities at Sellafield (UK) and La Hague (France). The anthropogenic 129I inventory in the central Arctic Ocean was found to increase proportionally to the integrated 129I releases from these reprocessing facilities. The interaction and origin of water masses in the region have been clearly distinguished with the help of 129I labeling. Predictions based on a compartment model calculation showed that the Atlantic Ocean and deep Arctic Ocean are the major sinks for the reprocessed 129I.

    The variability in 129I concentration measured in seawater along a transect from the Baltic Sea to the North Atlantic suggests strong enrichment in the Skagerrak–Kattegat basin. The 129I inventory in the Baltic and Bothnian Seas is equal to ~0.3% of the total liquid releases from the reprocessing facilities.

    A lake sediment core sampled in northeastern Ireland was analyzed for 129I to study the history of the Sellafield releases, in particular the nuclear accident of 1957. High 129I concentration was observed corresponding to 1990 and later, while no indication of the accident was found.

    The results of this thesis research clearly demonstrate the uniqueness and future potential of

    129I as a tracer of processes in both marine and continental archives.

    List of papers
    1. Computer simulation of ion-beam optics in a gas-filled magnetic spectrometer
    Open this publication in new window or tab >>Computer simulation of ion-beam optics in a gas-filled magnetic spectrometer
    2004 (English)In: Nucl. Instrum. Methods Phys. Res. Sect. B, Vol. 223-224, p. 180-184Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92484 (URN)
    Available from: 2004-12-20 Created: 2004-12-20 Last updated: 2009-03-26Bibliographically approved
    2. Anthropogenic 129I in seawater along a transect from the Norwegian Coastal Current to the North Pole
    Open this publication in new window or tab >>Anthropogenic 129I in seawater along a transect from the Norwegian Coastal Current to the North Pole
    2004 (English)In: Mar. Pollut. Bull., Vol. 49, p. 1097-1104Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92485 (URN)
    Available from: 2004-12-20 Created: 2004-12-20 Last updated: 2009-03-26Bibliographically approved
    3. Tracing water masses with 129I in the western Nordic Seas in early spring 2002
    Open this publication in new window or tab >>Tracing water masses with 129I in the western Nordic Seas in early spring 2002
    2004 (English)In: Geophys. Res. Lett., Vol. 31, p. L19305 1-4Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92486 (URN)
    Available from: 2004-12-20 Created: 2004-12-20 Last updated: 2009-03-26Bibliographically approved
    4. Concentrations of 129I along a transect from the North Atlantic to the Baltic Sea
    Open this publication in new window or tab >>Concentrations of 129I along a transect from the North Atlantic to the Baltic Sea
    Show others...
    2004 (English)In: Nucl. Instrum. Methods Phys. Res. Sect. B, Vol. 223-224, p. 446-450Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92487 (URN)
    Available from: 2004-12-20 Created: 2004-12-20 Last updated: 2009-03-26Bibliographically approved
    5. 129I in the Arctic and Nordic Seas: numerical model approach and prognoses
    Open this publication in new window or tab >>129I in the Arctic and Nordic Seas: numerical model approach and prognoses
    (English)Manuscript (Other (popular science, discussion, etc.))
    Identifiers
    urn:nbn:se:uu:diva-92488 (URN)
    Available from: 2004-12-20 Created: 2004-12-20 Last updated: 2010-01-14Bibliographically approved
    6. A retrospective search for evidence of the 1957 Windscale fire in NE Ireland using 129I
    Open this publication in new window or tab >>A retrospective search for evidence of the 1957 Windscale fire in NE Ireland using 129I
    Show others...
    2005 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 39, no 9, p. 2927-2935Article in journal (Refereed) Published
    Abstract [en]

    The accident at Windscale in October 1957 resulted in the release to the atmosphere of a large quantity of radioactivity. The presented work is a retrospective search for evidence of contamination from the accident in the northeastern region of Ireland. A lake yielding a high-resolution sedimentary record was identified near the northeast coast of Ireland. This site was used to reconstruct the history of radionuclide input to the region, based on the analysis of a set of cores extracted from the lake. A chronology for sediment accumulation within the lake was established using radioisotopic dating techniques (including 270Pb). High-resolution gamma and alpha spectrometry techniques were used to quantify concentrations of 137Cs, 239,240Pu and 241Am, all of which were released during the accident. The primary radioactive component of the release was 131I (T1/2 = 8 days), but this short-lived isotope has long since decayed. However, 129I (T1/2 = 1.57 x 10(7) years) was also released during the accident, and in a known ratio to 131I. Recent advances in accelerator mass spectrometry now make it feasible to measure 129I at ultra-trace level and thereby retrospectively reconstruct 131I deposition. Clearly resolved concentration profiles for 137Cs, 239,240Pu and 241Am in the lake cores reflect known historical fallout trends. The data suggest that any contamination from the Windscale fire that might have reached this catchment has been overwritten by input from the testing of nuclear weapons in the atmosphere. A time-series for 129I in lake sediment shows that concentrations in recent sediments are approximately 10 times greater than concentrations recorded in strata corresponding to the period of maximum fallout of other radionuclides from atmospheric testing of nuclear weapons (1964). These recent increases in 129I are attributed to increased emissions from the nuclear industry. The study yields no evidence of any enhancement in radioisotope concentrations, over and above global fallout, in strata dated to 1957, and we conclude that contamination from the Windscale fire had negligible impact on the northeastern region of Ireland.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-92489 (URN)
    Available from: 2004-12-20 Created: 2004-12-20 Last updated: 2017-12-14Bibliographically approved
  • 12.
    Alsterlund, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Effektiva återkopplingsverktyg för elanvändning: En studie som syftar till att identifiera utvecklingsmöjligheter för att uppnå ett mer hållbart energisystem år 20302015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Feedback tools support electricity users within the Swedish residential sector to increase their knowledge of electricity and the electricity market as well as to become more aware of their electricity consumption, which in turn encourages a reduction and an increased flexibility of electricity use. The primary aim of this study is to identify and analyse how existing feedback tools can be improved, to ensure that they contribute efficiently to the achievement of the EU objectives congruent with a more sustainable energy system in 2030, emphasizing: greenhouse gas reduction, increased energy efficiency and an increased share of renewable energy. In order to reach the primary aim of this study, existing feedback tools have been identified and mapped and interviews with feedback tools providers have been conducted. The study is limited to three research areas: the practical functions of feedback tools, available technology and the use of feedback tools.

    The use of more efficient feedback tools will provide an increased success rate for energy management, which includes both behavioural changes and energy efficiency. According to the results from the interviews conducted for this study, an increased use and user frequency is important to utilise the energy management potential. Efficient feedback tools can be achieved by developing existing tool functions. The desired development aims to reduce the effort required of the user, promote immediate and continuous feedback and to increase usability. However, the study shows that in order to achieve maximum effect, adaptions to specific needs of the users have to be made. An increased efficiency may also be achieved with additional features to allow more flexible consumption and encourage further energy efficiency measures.

    The technical aspect is important in order to implement more efficient feedback tools. Existing techniques for data collection should be developed in order to reduce the effort required of the user, enhance the quality and resolution of the data and finally prevent technology limitations, hence enabling feedback tools to be used by all users.

  • 13.
    Amanda, Holmkvist
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics, Byggteknik.
    Inverkan av torktemperatur vid vattenmättning av bruk och betong: Bestämmning av vattenmättnadsgrad och hydraulisk konduktivitet2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, there is uncertainty about how much the results differ when drying concrete

    at 20, 50 and 105 °C prior to saturation of concrete in order to determine the

    degree of saturation and hydraulic conductivity. Micro-cracks occur when concrete is

    dried at higher temperatures and causes increased hydraulic conductivity. Further, the

    concrete is believed not to be completely saturated if not all the physically bound

    water, so called free water, has been dried out prior to saturation.

    This thesis compares the effect of three different drying temperatures on the

    possibility to saturate concrete with water. The work was conducted at Vattenfall’s

    concrete laboratory in Älvkarleby. The three drying temperatures were +20 °C

    (room temperature), 50 °C and +105 °C. The objective was to determine if

    differences on the degree of saturation and hydraulic conductivity were non-existent

    or negligible. Vacuum saturation after drying at 105 °C is considered to be complete.

    The results after drying at 20 °C and 50 °C were compared to those after drying at

    105 °C. The results of the tests indicate that the concrete should be dried at +105°C

    prior to saturation with water. Then the risk of frost damage to concrete in hydro

    power structures can be assessed.

    How determination of the hydraulic conductivity is affected by the drying

    temperature gave more vague and dubious results. All specimens showed a maximum

    hydraulic conductivity after drying at 50 °C, not after 105 °C as expected. It was

    believed that the hydraulic conductivity theoretically would increase because of

    (more) micro-cracks when being dried at 105 °C. Results from the concrete with vct

    1.0 gave results that indicated that the specimens had been damaged by method 1. To

    sum up, the results of the tests indicate that further studies on the effects of drying

    temperatures should be made.

  • 14.
    Ammon, Anton
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Comparing the benefits of energy saving measures with seasonal solar thermal heat storage2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis compares the effects of energy saving measures with Active Solar Energy

    Storage (ASES) on a property owned by Stena Fastigheter. The building is located in

    Lövgärdet in Gothenburg and was a part of the Million Homes Program. It was built in 1967, has 9 floors, a heated basement and is heated by district heating. The thermal envelope of the building consists of the walls, doors, windows, roof/attic and the basement.

     

    ASES is a system consisting of solar panels on the roof of a building connected to the heating system. The solar energy that cannot be used immediately is stored in a ground storage unit for when it is needed. ASES can also be supplemented by geothermal heating by drilling boreholes into the ground and, via a Ground Source Heat Pump (GSHP), using the heat in the underlying rock.

     

    The ASES and GSHP system combined were compared to energy saving measure on the thermal envelope in terms of reducing the need for purchased energy and increasing profitability. The energy saving measures were: changing the 2-pane windows to 3-pane windows (either by adding a window pane or changing to a 3-pane window), insulating the façade, insulating the attic, insulating and draining the basement, changing doors, replacing the heat exchanger with a more efficient one, and improving ventilation system. The new system, called FTX, reuses the heat from the exhaust air to save energy.

     

    The results of the thesis show that it is difficult to make energy saving measures profitable. Of the measures evaluated, draining and insulating the basement is extremely cost effective, with a payback time of less than two years. Other profitable measures are insulating the walls (renovation costs of the wall excluded) and insulating the attic, but with a much longer payback time. The ASES and GSHP system are profitable and greatly reduced the need for purchased energy, but require a long payback time. The sum of all energy saving measures does not reduce the need for purchased energy as much, or as cheaply, as ASES, which reduced the energy usage by 62 %.

     

    Due to limited solar panel area ASES cannot supply enough heat to cover the heat demand of the studied building. ASES is therefore believed to be better suited for the buildings that surround the evaluated building. The surrounding buildings have fewer storeys, larger roof area where solar panels can be mounted, and open areas better suited for the ground storage. The potential to implement the ASES system for buildings like these from the Million Homes Program should be evaluated further.

  • 15. Andersson, Agnes
    Battery energy storage systems in Sweden: A national market analysis and a case study of Behrn sport arena2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The renewable energy sources increase the volatility on theelectricity market. To manage the quick variations battery energystorage systems (BESS), together with other storing solutions, willbe required in the future. Depending on which level in the grid thebattery is placed, it can serve different purposes. In this report amarket analysis is conducted, which examine the performance ofbattery storages installed in Sweden. Further on, a simulation, withPV-panels and a battery, was performed at Behrn Arena in Örebro.

    From the market analysis it was shown that the majority of therespondents had used, or will use, their battery for peak shaving.This function is particularly meaningful for customers with a powertariff, which is the case for Behrn Arena. The simulated systemdecreased their yearly cost due to the power tariff with 70 000 SEKand the total electricity bill decreased with 155 000 SEK.

    For the batteries to be more profitable in the future, the batteryprice needs to decrease or the number of revenue streams need toincrease. One revenue with great potential is frequency regulation,which has proven its efficiency in other countries.

  • 16. Andersson, Elinda
    Vidareutveckling av metod för bedömning av miljöpåverkan i samhällsekonomiska analyser vid investeringar i det svenska elstamnätet2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Svenska kraftnät, which is the authority responsible for the Swedish national grid, performs cost-benefit analysis (CBA) to assess which of different investment projects that are of greatest benefit to society. The environmental impacts are also estimated during this analysis. In this paper, a tool for estimating the environmental impacts during the lifetime of a grid component has been developed with the purpose of enabling a more complete environmental evaluation. A life cycle assessment was performed to develop the tool. The impact categories that have been studied are climate change (kg CO2-eq), freshwater eutrophication (kg P-eq), particulate matter formation (kg PM10-eq) and terrestrial acidification (kg SO2-eq). To be able to compare the environmental effects with other costs and benefits in the CBA a monetary valuation of the impact categories has been established. The result of this paper indicates that the AC-overhead line is the technology that contributes with the lowest environmental impact during the life cycle. This result, however, is obtained when analyzing different technical alternatives with the same preconditions, which rarely is the case in real projects. The result can therefore differ between different investment projects. The tool enables an assessment of the environmental impacts of different investment projects in the Swedish national grid, and is therefore an important part of the cost-benefit analysis to determine which alternative is best suited. 

  • 17.
    Andersson, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics.
    Småskalig elproduktion i urban miljö: Fallstudie av elproducerande system på ett handelscentrum2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates if a system for small scale electricity production located in anurban environment can be profitable. The work has been divided up into two parts,one extensive literature study and one case study. The purpose of the literature studywas to investigate the area, resulting in a choice of which technology to be studied indepth in a case study.In the case study a system containing small scale wind turbines and photovoltaicsmounted on Gränby Centrums roof was examined. From data containing wind power,wind direction and total irradiation, possible production from a system weresimulated. Three products of each technology were examined in the simulations.From the simulated production an economic analysis was carried out, this toinvestigate if a system is profitable. The two alternatives that showed the besteconomic result formed the optimal system.The economic analysis showed that none of the investigated alternatives whereprofitable, this because the capital costs exceeded the revenues. The revenues fromthe wind turbines were low because of the poor wind conditions in an urbanenvironment and the revenues from the photovolatics were low because of the lowelectricity price.

  • 18.
    Andersson, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Wengberg, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Utvärdering av konsekvenserna för nätanslutning av vindkraftparker i Sverige vid införandet av nätkoden Requirements for Generators2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Grid codes are becoming more demanding on power generating units due to the factthat the complexity of the power grid is increasing. The penetration of wind powerhas grown over the last years and it is clear that wind farms need to be addressedwith the same type of grid codes as conventional generation units. There is howeveran undeniable difference between the technology in conventional synchronousgeneration units, and the asynchronous generation units in wind farms.

    This thesis has reviewed the current grid code in Sweden and compared it to the newcode proposed by ENTSO-E, “the Requirements for Generators”, in the aspect ofwind farms with an installed power of 30 MW or more. The comparison has beencomplemented by an analysis of how wind farms of two different technologies(Doubly fed induction generators and full power converters) can meet therequirements and technical proposals have been given on how to be able to meetcompliance with the new grid codes.

    The Requirements for Generators contains many non-exhaustive and optionalrequirements, because of this it has been difficult to, at this stage, exactly point outthe technical impact on the grid connection of future wind farms in Sweden. For manyof the requirements in the Requirements for Generators there is no equivalent in theSwedish Grid Code (SvK FS2005:2) but counterparts can thus be found in existingpractices and therefor does not imply any major differences for the industry.

    The requirements of frequency regulation, synthetic inertia and reactive powercapability are the main components of the RfG which will require additional softwareand hardware installations for future wind farms in Sweden.

  • 19.
    Andersson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Bergenstråle, Terese
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Andersson Cada, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Fastlund, Martina
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Johansson, David
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Sigvant, Jonathan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Avfallsmängder: En studie om varför den genererande vikten avfall skiljer sig ifrån den förväntade vikten inom distrikt C i Uppsala kommun2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I detta projekt har en undersökning gjorts om varför den teoretiskt beräknade vikten avfall skiljer sig från den vikt som faktiskt samlats in. Det har gjorts på uppdrag av Uppsala Vatten och Avfall AB med fokus på distrikt C i Uppsala kommun. Projektet har grundat sig i att besvara Uppsala Vattens hypotes om att verksamhetsavfall (så som avfall från restauranger, tobaksaffärer och äldreboenden) väger mer än avfall från villor och flerbostadshus, samt verifiera om genereringstakten [kg/hushåll och vecka] som beräkningarna baserats på stämmer. Analysen gjordes utifrån tillhandahållna körlistor från Uppsala Vatten. För att undersöka Uppsala Vattens hypotes beräknades avfallsdensiteter utifrån de erhållna genereringstakterna av avfall för villor och flerbostadshus. Medelvärden för avfallsdensiteter uträknade från den totala kärlvolymen beräknades för villor, flerbostadshus samt verksamheter till 0.0475 [kg/l], 0.224 [kg/l], respektive 0.408 [kg/l]. Resultaten visade en stark indikation på att verksamhetsavfall väger mer än hushållsavfall och därmed stämmer troligtvis Uppsala Vattens hypotes. Resultatet från körlistorna bekräftade dock inte hypotesen fullständigt då det finns en osäkerhet i datan vilket genom metoden som används för beräkningar av avfallsdensiet gör att resultatet inte kan ses som ett direkt bevis. Verifieringen av genereringstakten har inte kunnat genomföras p.g.a att datan som analyserats i projetet inte hade den karaktär eller omfattning som behövdes. För att möjliggöra detta hade det behövs fler körlistor samt körlistor(ordlista Appendix A) med enbart verksamheter. Avslutande rekommendationer är att utforma en specialanpassad körlista som endast hämtar avfall från verksamheter, flerbostadshus eller villor för att direkt avfärda eller bekräfta Uppsala Vattens hypotes och dess genereringstakt från plockanalyserna.

  • 20.
    Andersson, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Bernström, Vendela
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Törnqvist, Joacim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Hosting Capacity of a Low-Voltage Grid: Development of a Simplified Model to be used in future Solar Roadmaps2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this bachelor thesis is to assess whether it is possible to create a simplified model that estimates the hosting capacity of a low-voltage grid. The Simplified model is compared with a more elaborate model created by the Built Environment Energy Systems Group (BEESG) at Uppsala University. The Simplified model takes three easily obtainable variables into account. The model created by BEESG allows us to observe both the amount of photovoltaic (PV) power that is installed as well as the voltages in each bus in a grid. The hosting capacity is found by gradually increasing the amount of PV power installed in a low-voltage grid until overvoltage is reached. Simulations with BEESG’s model are done for a week in July when the PV generation has its peak and the load is generally low. The Simplified model is created using linear regression with the calculated values from the BEESG’s model as a reference. The report shows that the Simplified model will give an estimation of the low-voltage grid’s hosting capacity that is comparable to the value calculated with BEESG’s model. The results show that it is rarely the low-voltage grid that restricts the installation of PV facilities and that a high self-consumption is advantageous regarding to the grids hosting capacity.

  • 21.
    Andersson, Viktoria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Elbilar på Lidingö: Påverkan på det regionala elnätet2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis aims towards increasing the understanding of how the growing number of electric cars is going to affect the regional power grid of Stockholm. The results are meant to aid in long term planning of maintenance and development of the regional power grid. Three possible scenarios are presented for the development of electric cars on Lidingo until the year 2040. The number of electric cars, maximum load and load profiles are calculated and analyzed for each scenario. Possible measures of value for the DSO Ellevio are then presented.

    By the year 2040 it is likely that at least one fourth of cars are electric. The maximum power loads from the charging of electric cars will coincide with already existing power peaks during early evening. Loads from charging of electric car will cause a significant contribution to the loads of the regional power grid. If international, national and local climate goals are to be fulfilled the loads would be even larger, though that scenario is deemed unlikely. It is concluded that extensive measures in the regional power grid of Lidingo are needed in order to handle the new maximum loads. It is suggested that Ellevio should start planning for upgrading components, install energy storages and work for load shifting in order to handle the higher loads.

  • 22.
    Apelfröjd, Senad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bülow, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Kjellin, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Eriksson, Sandra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Laboratory verification of system for grid connection of a 12 kW variable speed wind turbine with a permanent magnet synchronous generator2012In: EWEA 2012 Annual Event, Copenhagen, Denmark, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    In this paper the first laboratory tests of the gridconnection system, connected to a resistiveload, for a vertical axis wind turbine (VAWT)with a permanent magnet generator arepresented. The system is based on a taptransformertopology with a voltage sourceinverter and an LCL-filter. The use of a taptransformer topology eliminates the need for aDC-DC converter to handle the variations inDC voltage. The harmonic content of thecurrents from experiments and simulationsperformed in Simulink using different taps onthe transformer are presented. The simulatedcurrents, fed to the resistive load, have a totalharmonic distortion (THD) of 0.5% to 0.9% forthe different taps. The experimental systemhas a current THD ranging from 1.8% to 2.8%.The difference is expected to be due tounbalances, delays and dead times in theexperimental set-up as the major THDcontribution is from harmonic orders below 11.The results show that an LCL filter can bedesigned to meet the demands on powerquality for grid connection of the system withall the taps of the tap transformer inaccordance with IEEE 519-1992.

  • 23.
    Apelfröjd, Senad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Eriksson, Sandra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bernhoff, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    A Review of Research on Large Scale Modern Vertical Axis Wind Turbines at Uppsala University2016In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 9, no 7, article id 570Article, review/survey (Refereed)
    Abstract [en]

    This paper presents a review of over a decade of research on Vertical Axis Wind Turbines (VAWTs) conducted at Uppsala University. The paper presents, among others, an overview of the 200 kW VAWT located in Falkenberg, Sweden, as well as a description of the work done on the 12 kW prototype VAWT in Marsta, Sweden. Several key aspects have been tested and successfully demonstrated at our two experimental research sites. The effort of the VAWT research has been aimed at developing a robust large scale VAWT technology based on an electrical control system with a direct driven energy converter. This approach allows for a simplification where most or all of the control of the turbines can be managed by the electrical converter system, reducing investment cost and need for maintenance. The concept features an H-rotor that is omnidirectional in regards to wind direction, meaning that it can extract energy from all wind directions without the need for a yaw system. The turbine is connected to a direct driven permanent magnet synchronous generator (PMSG), located at ground level, that is specifically developed to control and extract power from the turbine. The research is ongoing and aims for a multi-megawatt VAWT in the near future.

  • 24.
    Appelstål, Sophia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Teknisk utvärdering av befintliga och potentiella teknologier för automatisk frekvensreglering i det svenska elnätet2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The increasing amount of renewable energy in the power system have led to new challenges to balance supply and demand in the electric grid. To maintain the balance in the power system the system operator can activate power reserves to restore the balance at a frequency deviation. Today these reserves consist exclusively of hydropower in Sweden. With more volatile power generation new types of technologies to provide these reserves are desirable.

    The aim of this master thesis is to investigate the technical potential for using wind power, demand response and energy storage for automatic frequency control in the Swedish power system. The thesis examines the performance of the different technologies to see if they meet the technical requirements for delivering reserves set by the TSO. Moreover, the available capacity from the technologies throughout the year are estimated.

    The results show that all three technologies potentially could be used for frequency control. However, the technical requirements are not always fulfilled. In order to enable new technologies to provide power reserves some of the requirements needs to be modernized. Generally, demand response proved to have the largest available capacity for frequency control today. The study shows that demand response from industries and electric heated households could potentially provide all automatic frequency control. Modern wind turbines can be used for frequency control and for down regulation of the frequency the potential is considerable. Energy storages are not yet widely used in Sweden but with reduced costs they can play an important role in regulating the frequency in the future.  

  • 25.
    Arding, Karin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    In de Betou, Siri
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Making grid capacity available through heat pump control2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this report the problem of constructing a bus depot with electrical buses despite the lack of grid capacity, was analyzed. A potential solution is investigated, namely smart control of heat pumps in industries. The possibility of allocating grid capacity to the bus depot by reducing power consumption in heat pumps during peak hours, is taken into consideration. The maximum amount of released capacity in an industrial area is calculated through the controlling of heat pumps. This investigation was made through simulations with a simplified building energy model (lumped capacity model) which was applied to a reference building.

    After mapping the area Boländerna and the geothermal wells located there, IKEA Uppsala was chosen as the reference building, since a third of the total number of wells were found in that area. To take the whole capacity of Boländerna into account, the model was scaled up to estimate the total, possible reduction of power. The bus depot requires 6 MW nighttime and 4 MW daytime, the total amount of electrical power that could be withdrawn, if all heat pumps were on maximum heat, in the chosen area were 0.75 MW and by controlling the heat pumps during an optimized level, the amount of 142 kW could be made available to the electric grid. 142 kW is not enough cover the need for the bus depot but it could supply the need for a slow charger to one of the buses and is therefore a possible sub-solution to the larger problem.

  • 26. Arfvidsson, J.
    et al.
    Bjelke-Holtermann, B.
    Mattsson, J.
    Status determination and risk assessment of measures in historic buildings2018In: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, p. 345-353Conference paper (Refereed)
  • 27. Artigas, D.
    et al.
    O’Brien, S.
    Aijazi, A.
    An unfair reputation: The energy performance of mid-century metal-and-glass curtain walls2018In: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, p. 391-400Conference paper (Refereed)
  • 28.
    Arumägi, Endrik
    et al.
    Chair of Building Physics and Architecture, Tallinn University of Technology, Estonia.
    Kalamees, Targo
    Chair of Building Physics and Architecture, Tallinn University of Technology, Estonia.
    Broström, Tor
    Gotland University, School of Culture, Energy and Environment.
    Indoor climate in a naturally ventilated unheated medieval church in Harju-Risti, Estonia2010In: 10th REHVA World congress Clima 2010: Sustainable Energy Use in Buildings, 2010Conference paper (Refereed)
    Abstract [en]

    Indoor climate in a naturally ventilated unheated medieval church was analysed to determine if the conditions existing suit for three medieval wooden sculptures forming the Calvary group that were decorated the church until 1958. The values of temperature and RH were measured with data loggers at 1-h intervals inside and outside the church. Ventilation measurements were performed using a passive tracer gas technique. The current study shows that there is a considerable risk in bringing back the medieval sculptures forming the Calvary group to the Harju-Risti Church without creating conditions for indoor temperature and humidity regulation. To start risk assessment it is required to maintain a RH level that prevents the risk of mould growth, reduce fluctuations of air RH annually and in the short term period, avoid of too high and too low humidity levels in church that could cause flaking, peeling and cracking of wooden sculptures.

  • 29.
    Arvidsson, Mari
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Analys av mellanspänningsnätet i centrala delar av Västerås stad2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The dependency of continuous electricity supply is high in the Swedish society today, at the same time no one is willing to pay for a too costly or over dimensioned power distribution system. The owners of the distribution systems are the ones responsible for this balance act of maintaining a high quality of electricity delivery to customers at a reasonable cost.

    In this master thesis a limited part of the primary distribution system (10 kV), owned by Mälarenergi Elnät AB and located in the city centre of Västerås, was chosen for a deeper analysis of its reliability. Its ability to handle outages of system components (N-1 and N-2 contingency analysis) was investigated to find out potential weak spots and parts of the grid that showed signs of being overdimensioned.

    The results of the performed simulations showed that in 74 % of the studied N-1 contingencies cases, consisting of outages of a bus bar in a distribution substation, the system could handle this without causing outages in other parts of the grid. For the N-2 contingencies 61 % passed the test. It was also found that one of the two included high voltage substations could alone supply the investigated part of the grid. Some cables and transformers were found to be more or less unnecessary, whereas other components proved to be overloaded in several situations.

  • 30.
    Asai, Ryoko
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Designing "Open Education": How does the ICT-based system function as a new medium of participation for sustainability?2013In: The possibilities of ethical ICT, Kolding: University of Southern Denmark , 2013, p. 33-36Conference paper (Refereed)
    Abstract [en]

    Information and communication technology (ICT) has developed and deployed rapidly since 1980’s. Until now ICT has been considered as one of the most important infrastructures in living in the present globalized society. Along with diffusion of personal computers and highly leveraging information on the web, the way of learning has been changing gradually. Hundreds universities, institutes and companies constructs and releases the “open education” platform based on ICT, for example iTunes U, TakingITGlobal and so on. These open education platforms are basically open for everyone who wants to learn by using contents on the website for free in so far as they can access the Internet. And the movement toward the construction and use of ICT-based education platform is supported by international organizations, such as the Centre for Educational Research and Innovation (CERI) in OECD and UNESCO’s project “the Virtual University and e-learning”.

  • 31.
    Axelius, Torun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Hellström, Josefine
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Integration of sustainable management in retail: A case study of The Lobby - AMF Fastigheter2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The increasing environmental problems have today become global and changes are dras-tically needed in all levels of society. Customers’ buying behaviour can play a big partand it is possible to both contribute to a more sustainable world and add economic valueto a business, but new sustainable business models are needed. In this research projectThe Lobby, a new innovative marketplace owned by AMF Fastigheter, has been usedas a case study to find the key areas in retail business where change is most important.Furthermore, a life cycle assessment has been conducted to see where in a T-shirt’s lifecycle the most CO2equivalents are released and what the difference between a T-shirtbought at a physical store and e-commerce is. This research project has found that themost important area to focus on if sustainability is to be integrated successfully in aretail business is the company management. The commitment and attitude the companymanagement mediates to their employees is crucial for success. For The Lobby it is alsoimportant to evaluate which retailers they choose to approve due to the fact that its in-directly affecting their sustainability. The Lobby should also try to be more transparentand informative. By promoting their sustainability actions they can attract both cus-tomers and future retailers. But the research and knowledge in the field of influencingand changing customers’ behaviour is still limited and more research is needed.

  • 32.
    Axelius, Torun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Hellström, Josefine
    Torpner, Jessie
    Trinh, Yvonne
    von Greyerz, Karin
    Office Recycling: Analys utifrån Triple Bottom Line2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Office Recycling Sverige AB efterfrågade en hållbarhetsrapport som kan användasinom företaget men även mot kunderna. I studien analyserades processer i företagetför att undersöka och kunna optimera verksamheten där resultatet sedan kan användassom underlag till en hållbarhetsrapport. Som metod valdes Triple Bottom Line därekonomiska, miljömässiga och sociala aspekter ingår. Alla undersökningar sompresenteras i rapporten utfördes enligt denna modell.I studien undersöktes hur utformningen av en hållbarhetsrapport utförs samt hurimplementering av Triple Bottom Line sker i företagets verksamhet. Undersökningarutfördes dessutom på företaget i helhet vilket innefattar företagets verksamhet,transporter inom företaget, produkten Miljörör och certifieringar. Studien har givitkunskap om företagets struktur och vilka områden som behöver optimeras ochförbättras i framtiden.Ett flödesschema över företagets processer skapades för att bättre förståkommunikationen inom Office Recycling men även hur det ser ut mot kunderna. Deresultat som har erhållits är att kommunikationen inom företaget är bristfällig enligtenkätundersökningen som skickades ut till servicepersonalen. Enkäten gav ävenresultat om arbetsmiljön där servicepersonalen anser att arbetet är stressigt och tungt.Office Recycling är märkta med Bra Miljöval för företagets val av biogas somdrivmedel i transporterna vid hämtning av verksamhetsavfall. Företaget är ävencertifierad med Fossilfritt Sverige och ISO-standarderna inom kvalité och miljö, ISO9001 respektive ISO 14001.Office Recycling har fått en utökning av kunder vilket bidrar till investeringen i tvånya servicebilar. Servicebilarna måste placeras på ett optimalt sätt för att underlättaarbetsbördan hos servicepersonalen, därför har tre förslag tagits fram som har utgåttfrån ekonomiska, sociala och miljömässiga aspekter. Resultatet är att förslag två ärdet mest optimala av de tre förslagen.

  • 33.
    Ayob, Mohd Nasir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Castellucci, Valeria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Abrahamsson, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Svensson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Waters, Rafael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Control Strategy for a Tidal Compensation System for Wave Energy Converter Device2018Conference paper (Refereed)
  • 34.
    Ayob, Mohd Nasir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. Univ Malaysia Perlis, Sch Mechatron Engn, Arau 02600, Perlis, Malaysia.
    Castellucci, Valeria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Waters, Rafael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Wave energy potential and 1-50 TWh scenarios for the Nordic synchronous grid2017In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 101, p. 462-466Article in journal (Refereed)
    Abstract [en]

    This study estimates the wave energy potential along the coasts of the Nordic countries with the Nordicsynchronous grid as a chosen boundary. A model for wave farm allocation was developed and applied to achieve annual energy production targets of 1 TWh, 3 TWh, 10 TWh and 50 TWh. The study is based on 10 years of data, from 2005 to 2014, from the European Center for Medium-Range Weather Forecasts. Data from a total of 728 coordinate points along the Nordic countries, with a 0.125° x 0.125° spatial resolution, were considered. An algorithm was developed to generate the scenarios, to estimate the installed capacity of wave farms at different locations along the coasts, and to measure the physical space required by the farms. This analysis of the four energy target scenarios resulted in a required installed capacity of 337 MW, 1.02 GW, 3.42 GW and 17.09 GW, covering a stretch of the total coast of 0.4, 1.2, 3.8 and 18.9% respectively. The total annual wave energy resource for the Nordic countries is determined at 590 TWh, most of which is available along the Norwegian coast.

  • 35.
    Ayotte, John
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control.
    Dynamic positioning of a semi-submersible, multi-turbine wind power platform2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As a growing market for offshore wind power has created a niche for deep-water installations, offshore floating wind solutions have become more and more viable as a renewable energy source. This technology is currently in development and as with many new technologies, many traditional design methods are found lacking. In the multi-turbine platform design investigated, turbine units are placed closely together to conserve material use and reduce cost, however with such tightly spaced turbines; wake interaction poses a threat to the productivity and the lifespan of the installation. In order to fully capitalize on the substantial increase in available wind energy far at sea, it is important that these floating parks operate in an optimal way. The platform investigated in this report sports 3, 6MW turbines which must be positioned such that wake interference is minimized; the platform must always bear a windward heading. 

    Maneuvering ocean going vessels has been practiced using automated dynamic positioning systems in the gas and oil industry for over 50 years, often employing submerged thrusters as a source of propulsion. These systems are mostly diesel powered and require extra operational maintenance, which would otherwise increase the cost and complexity of a floating wind farm. In this paper, it is suggested that the wind turbines themselves may be used to provide the thrust needed to correct the platform heading, thus eliminating the practical need for submerged thrusters. By controlling the blade pitch of the wind turbines, a turning moment (torque) can be exerted on the platform to correct heading (yaw) relative wind direction. Using the Hexicon H3-18MW platform as a starting point; hydrodynamic, aerodynamic and electromechanical properties of the system are explored, modeled and attempts at model predictive control are made. Preliminary results show that it is possible to control the H3’s position (in yaw) relative the wind using this novel method.

  • 36.
    Balksten, Kristin
    et al.
    Gotland University, School of Culture, Energy and Environment.
    Broström, Tor
    Gotland University, School of Culture, Energy and Environment.
    Myrin, Malin
    Tyréns AB.
    Thelin, Carl
    Tyréns AB.
    Kettunen, Rebeca
    Gotland Museum.
    Mebus, Ulrika
    Gotland Museum.
    Increased use of ruins through secured masonry and comfortable climate2010In: Proceedings of the 7th International Conference on Science and Technology in Archaeology and Conservation, Petra, Jordan, 2010Conference paper (Other academic)
    Abstract [en]

    This paper presents a unique scientific research project, funded by the KK-foundation in Sweden together with several companies participating in the project. A primary goal is to find methods to examine and take care of open masonry constructions thereby enabling an increased use of them in a safe and comfortable way without diminishing their cultural values. A second goal is to establish a long-term cooperation/network of researchers, conservators, engineers, antiquarians and craftsmen that can keep and develop the knowledge. The project takes place in year 2010 and 2011. This paper presents a model of cooperation as well as the ongoing experiment and expected results. The project is divided into three major parts:1) Description and assessment of historic masonry as load bearing structures. 2) Assessment of stone and mortar in old masonry and finding the methods to secure and preserve them. 3) The climate in the ruin with respect to comfort and preservation. The goals for the different parts of this research project are to find the best possible solutions of how to: a) Evaluate the construction of complex masonry structures to enable new additions that are appropriate with respect to statics. b) Find efficient methods to evaluate and conserve the status of the materials (stone, mortar) and walls in old masonry to grant safe accessibility. c) Create a comfortable climate in an open masonry structure without closing it. These three research areas all focus on the historic masonry which at the same time forms the climate shell, the bearer of plaster and the historical setting to the activities that are to take place in the ruin.

  • 37.
    Balksten, Kristin
    et al.
    Gotland University, School of Culture, Energy and Environment.
    Steenari, Britt-Marie
    Department of Chemical and Biological Engineering, Environmental Inorganic Chemistry, Chalmers University of Technology, Gothenburg, Sweden.
    The influence of particle size and structure in hydrated lime on the properties of the lime putty and lime mortar2010In: International journal of architectural heritage, ISSN 1558-3058, Vol. 4, no 2, p. 86-101Article in journal (Other academic)
    Abstract [en]

    In this work, scanning electron microscopy (SEM) analysis of lime slaked in different ways and analysis of thin section of lime putty and mortar specimens by light microscopy was combined with practical tests and field studies to evaluate the impact of the slaking technique on the properties of the lime putty as well as the structure of the fresh and carbonated mortar. The lime slaking methods studied were wet slaking and earth slaking, giving lime putties with very different consistency and workability. The aim of this work was to use microscopy techniques to explain these differences in properties and to investigate if it is possible to use these analytical methods to recognize the lime-slaking technique used in a historical lime mortar. The results obtained by SEM show significant differences in structure between the lime putties. The earth-slaked lime consists of relatively large particles that are packed in a porous system compared with the wet-slaked lime with very small particles closely packed in a dense structure. After storing, the wet-slaked lime gives a putty that has a dense and clearly defined stratified structure, whereas the earth-slaked lime is porous and has no stratification.

  • 38. Banfill, P.F.G.
    Hygrothermal properties of NHL mortars2018In: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, p. 71-79Conference paper (Refereed)
  • 39.
    Barrios Rivero, Matías
    Karlsruhe Institute of Technology (KIT), Institute of Applied Geosciences (AGW).
    EVALUATION OF AN AQUIFER THERMAL ENERGY STORAGE (ATES) SYSTEM FOR THE CITY HOSPITAL IN KARLSRUHE (GERMANY)2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The objective of the present study is to evaluate the economic, technical and environmental feasibility of an Aquifer Thermal Energy Storage (ATES) system combined with groundwater heat pumps (GWHP) for providing space cooling and heating for the future surgery building at the city hospital in Karlsruhe. The base case system used as reference for comparison is a system similar to the one currently supplying space cooling from a GWHP system and space heating by the local district-heating network. In addition, two alternative systems were included in the analysis, an Absorption Chiller (AbC) and a Desiccative Evaporative Cooling (DEC) system, both fed from the district-heating network. The study shows that the ATES system combined with a GWHP system is the most environmentally and economically attractive system for the planned facility. The results for the AbC system and the DEC systems show a negative net present value, meaning that this alternative is economically unfeasible. Furthermore, the AbC system and the DEC system do not provide any environmental advantage, showing an annual increase in CO2 emissions compared to the base case. A similar system like the one already providing cooling to some of the facilities would have several advantages over these two alternatives. However, it cannot compete with the ATES system together with GWHP, which apart from providing cooling at slightly higher efficiencies than the base case also delivers heating at high efficiencies. Therefore, it offers great potential savings and also provides an annual reduction in green house gas emissions. Concerning the technical feasibility of the four studied systems, no obstacle or significant barrier could be identified yet.

  • 40.
    Bartusch, Cajsa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Alvehag, Karin
    KTH Royal Institute of Technology.
    Further exploring the potential of residential demand response programs in electricity distribution2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 125, p. 39-59Article in journal (Refereed)
    Abstract [en]

    Smart grids play a key role in realizing climate ambitions. Boosting consumption flexibility is an essential measure in bringing the potential gains of smart grids to fruition. The collective scientific understanding of demand response programs argues that time-of-use tariffs have proven its merits. The findings upon which this conclusion rests are, however, primarily derived from studies covering energy-based time-of-use rates over fairly short periods of time. Hence, this empirical study set out with the intention of estimating the extent of response to a demand-based time-of-use electricity distribution tariff among Swedish single-family homes in the long term. The results show that six years after the implementation households still respond to the price signals of the tariff by cutting demand in peak hours and shifting electricity consumption from peak to off-peak hours. Studies conducted in the Nordic countries commonly include only homeowners and so another aim of the study was to explore the potential of demand response programs among households living in apartment buildings. The demand-based tariff proved to bring about similar, but not as marked, effects in rental apartments, whereas there are virtually no corresponding evidences of demand response in condominium apartments.

  • 41.
    Bartusch, Cajsa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Stikvoort, Britt
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Psychology.
    Residential demand response in the long run: Assessing the effects of a time-of-use power tariff 20 years after implementing it2018In: Behave 2018: Book of Abstracts / [ed] Hackenfort, Markus; Carabias-Hütter, Vicente; Hartmann, Cathérine; Janser, Marcel;: Schwarz, Natalie; Stücheli-Herlach, Peter, Zürich, 2018, p. 30-31Conference paper (Refereed)
  • 42.
    Bastholm, Caroline
    Högskolan Dalarna, Energiteknik.
    A user guide to simple monitoring and sustainable operation of PV-diesel hybrid systems: Handbook for system users and operators2015Report (Other (popular science, discussion, etc.))
    Abstract [en]

    This report contains a suggestion for a simple monitoring and evaluation guideline for PV-diesel hybrid systems. It offers system users a way to better understand if their system is operated in a way that will make it last for a long time. It also gives suggestions on how to act if there are signs of unfavourable use or failure. The application of the guide requires little technical equipment, but daily manual measurements. For the most part, it can be managed by pen and paper, by people with no earlier experience of power systems.The guide is structured and expressed in a way that targets PV-diesel hybrid system users with no, or limited, earlier experience of power engineering. It is less detailed in terms of motivations for certain choices and limitations, but rich in details concerning calculations, evaluation procedures and maintenance routines. A more scientific description of the guide can be found in a related journal article.

  • 43.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thermal modelling of a passively cooled inverter for wave power2015In: IET Renewable Power Generation, ISSN 1752-1416, E-ISSN 1752-1424, Vol. 9, no 4, p. 389-395Article in journal (Refereed)
    Abstract [en]

    Owing to very costly maintenance operations, the reliability of electrical systems for offshore renewable energy is a major issue to make electricity production economical. Therefore proper thermal management is essential in order to avoid the components from being damaged by excessive temperature increase. Both analytic and computational fluid dynamics (CFD) models were implemented to assess the temperature increase in the inverter installed in a submerged substation and during working conditions. It was shown that this inverter could transmit a total power of up to about 35 kW. This limit is dependent on a certain distance between the modules and a perfect thermal contact with the hull. The influence of several of such parameters as well as the efficiency of passive cooling were studied.

  • 44.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thermal Rating of a Submerged Substation for Wave Power2016In: IEEE Transactions on Sustainable Energy, ISSN 1949-3029, E-ISSN 1949-3037, Vol. 7, no 1, p. 436-445Article in journal (Refereed)
    Abstract [en]

    The costs of offshore maintenance operations put high reliability-requirements on offshore equipment for ocean energy, especially on submerged ones. Thermal management is thus essential in the design of the prototypes of a marine substation, developed at Uppsala University, for grid interface of wave power parks. The cooling system itself should be efficient as well as reliable. Therefore, the feasibility of a completely passive cooling strategy was evaluated. The studied substation includes various power components, which dissipate heat and are installed in one pressurized vessel. Thermal cross-coupling was investigated with 3-D submodels and a thermal network model. An electric circuit was coupled to determine the rated power of the substation. The results depend mainly on the dc-voltage, the seawater temperature, and the thermal contact between the components and the hull.

  • 45.
    Bee, Elena
    et al.
    Univ Trento, Dept Civil Environm & Mech Engn, Trento, Italy.
    Prada, Alessandro
    Univ Trento, Dept Civil Environm & Mech Engn, Trento, Italy.
    Baggio, Paolo
    Univ Trento, Dept Civil Environm & Mech Engn, Trento, Italy.
    Psimopoulos, Emmanouil
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Dalarna Univ, Energy Technol, Borlange, Sweden.
    Air-source heat pump and photovoltaic systems for residential heating and cooling: Potential of self-consumption in different European climates2019In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 12, no 3, p. 453-463Article in journal (Refereed)
    Abstract [en]

    Renewable sources will play a key role in meeting the EU targets for 2030. The combined use of an aerothermal source through a heat pump and a solar source with a photovoltaic (PV) system is one feasible and promising technology for the heating and cooling of residential spaces. In this study, a detailed model of a single-family house with an air-source heat pump and a PV system is developed with the TRNSYS simulation software. Yearly simulations are run for two types of buildings and nine European climates, for both heating and cooling (where needed), in order to have an overview of the system behaviour, which is deeply influenced by the climate. The storage system (electrical and thermal) is also investigated, by means of multiple simulation scenarios, with and without the battery and with different water storage sizes. The numerical results provide an overview of the performance of the considered heating and cooling system, as well as the balance of the electrical energy exchange between the grid, the building, and the PV array.

  • 46.
    Bender, Anke
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Francisco, Francisco G. A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Sundberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    A Review of Methods and Models for Environmental Monitoring of Marine Renewable Energy2017In: Proceedings of the 12th European Wave and Tidal Energy Conference, EWTEC , 2017Conference paper (Refereed)
    Abstract [en]

    A continued expansion of the marine renewable energy sector will result in an increased demand in monitoring the natural marine environment. This may be due to a basic scientific interest but is foremost linked to the requirement of pre- and post-construction studies in relation to environmental impact assessments and consenting processes for marine renewable energy projects. With focus on wave and tidal power, but without attempting to provide a comprehensive list, we review methods, technologies and other scientific tools used for monitoring and predicting possible impacts from marine energy installations, on both population and behavioural levels. This includes traditional methods such as fishing gear, like nets and cages, modern technologies such as platforms with multi parameter equipment and the use of deterministic models. This paper is intended to serve as an overview for technology developers as well as authorities, regulators and decision makers with interests in general techniques, and naturally for scientists and consultants commonly being executors of studies and monitoring programs. By giving relevant and up to date references this paper may also be useful for finding more detailed information on study methods and variants. Finally, we give recommendations on where development of technologies is needed in order to face future requirements.

  • 47.
    Bennich, Amelie
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Improving energy security for individual households during outages: A simulation study for households in Sweden2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this study, it was investigated how individual households could manage security of supply during an outage by installing a local energy system that could operate independently from the electricity grid. By installing local renewable off-grid energy systems, households could guarantee an uninterrupted supply of energy even during an outage on the electricity grid, while also increasing their energy autonomy during normal circumstances. The results showed that managing an outage during summer was fairly easy. Due to high electricity production, a small energy storage was enough to manage an outage during summer. However, managing an outage during winter was more critical. During winter, the systems needed to be almost fully reliant on the energy storage. This significantly increased the cost of these systems. Due to the high cost for the energy systems today, it was not considered a feasible solution to improve energy security at a national level. However, at a local level, this was considered to have the potential to improve energy security. First, it could to be of interest for people who already have installed solar panels, who could add a battery and thereby be able to manage an outage during summer. Second, it could be of interest for people who are more exposed to outages or have a low trust in the system to work properly. Lastly, this could be of interest for actors for whom backup energy is important, for instance for the industry.

  • 48.
    Berg, Josefin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Modelling Nitrogen Flows in Peri-urban Vegetable Field Plots in Nanjing, China2005Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Many parts of China are going through a rapid development and urbanization resulting in various environmental impairities. The Yangtze Delta Region surface water bodies are affected by eutrophication, partly caused by diffuse losses from agriculture. In this study, nitrogen, and to some extent also phosphorus, flows and losses from two plots in an intensively cultivated vegetable field in a peri-urban area of Nanjing, with a high input of organic fertilizer, were analysed by the use of the field-scale simulation model GLEAMS. The GLEAMS model was parameterized and calibrated against measurements of soil water and nitrogen content in two plots. A scenario with a reduced input of nitrogen was then simulated.

    The resemblance between simulated and measured water content in the different soil layers was quite poor. The simulated inorganic nitrogen content in the soil was significantly lower than the measured during great parts of the simulation period. This could be due to an inappropriate simulation of the mineralization of organic N under these conditions, or an underestimated decomposition rate of manure. It is also possible that the poor water simulations contributed to the underestimated inorganic N content in the soil. There were similar results for the two plots, except for an unexplained 20% increase in leaching and erosion losses of N in Plot B. For simulation of scenarios to find best management practices, the model parameterization should be further refined.

  • 49.
    Berggren, Björn
    et al.
    Lund University.
    Widén, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Karlsson, Björn
    Mälardalen University.
    Wall, Maria
    Lund University.
    Evaluation and optimization of a Swedish Net ZEB - Using load matching and grid interaction indicators2012In: Proceedings of the First Building Simulation and Optimization Conference, Loughborough, UK, September 10-11, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    Net Zero Energy Buildings, Net ZEBs, is one of many necessary measures for climate change mitigation as they may reduce the energy consumption in the building sector. The Net ZEB interacts with a grid infrastructure. It is therefore important to consider the interaction with the grid in the design phase.

    This paper reports an evaluation of a proposed designof a Net ZEB in the south of Sweden evaluating load matching and grid interaction using simulated datasets with hourly resolution. The aim was to find a design with as high load matching and as low grid interaction as possible.

    The results show difficulties of achieving a high load matching between the building load and on-site generation, due to the Nordic climate and the relatively low loads during daytime, when the availability of solar energy is high. The building is likely to accomplish the goal of a Net ZEB balance. If higher flexibility is sought, a larger energy storage should be considered.

  • 50.
    Berglund, Mårten
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Green growth? A consumption perspective on Swedish environmental impact trends using input–output analysis2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Consumption-based environmental impact trends for the Swedish economy have been generated and analysed in order to determine their levels compared to official production-based data, and to determine whether or not the Swedish economy has decoupled growth in domestic final demand from worldwide environmental impact. Three energy resources (oil, coal and gas use, as well as their aggregate fossil fuel use) and seven emissions (CO2, CH4, N2O, SO2, NOx, CO and NMVOC, as well as the aggregate CO2 equivalents) were studied.

    An augmented single-regional input–output model has been deployed, with world average energy and emission intensities used for products produced abroad. A new method for updating input–output tables for years missing official input–output tables, was also developed. For each of the resources and the emissions, two time series were generated based on two different revisions of Swedish national accounts data, one for the period 1993–2003, the other for the period 2000–2005. The analysis uses a recently revised time series of environmental data from the Swedish environmental accounts, as well as recently published global environmental data from the IEA and from the EDGAR emissions database (all data from 2010 or later). An index decomposition analysis was also performed to detect the various components of the time series.

    For fossil fuels consumption-based data don't differ much from production-based data in total. For the greenhouse gases there is a clear increase (CO2eq emissions increase approximately 20 % from 1993–2005, mainly driven by an increase in CH4 emissions), resulting from increased emissions abroad due to the increased demand for imported products. This suggests Sweden has not decoupled economic growth from increasing greenhouse gas emissions – contrary to what the slightly decreasing official production-based UNFCCC data say. For the precursor gases (SO2, NOx, CO and NMVOC), emissions are generally decreasing, with the exception of SO2 and NOx which increase in the second time series. For all emissions studied, consumption-based data lie at much higher levels than the official production-based UNFCCC data.

    However, further research is needed regarding the resolution of the data of the energy use and the emissions generated abroad by the Swedish domestic final demand. Also, extension of the time series and of the environmental parameters to such things as material use is needed to find out with more certainty to what extent Swedish growth has been sustainable or not.

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  • asciidoc
  • rtf