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  • 1.
    Andersson, Tobias
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningsmiljön Virtuell produkt- och produktionsutveckling.
    Svensson, Daniel
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningsmiljön Virtuell produkt- och produktionsutveckling.
    Andersson Lassila, Andreas
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningsmiljön Virtuell produkt- och produktionsutveckling.
    Modelling and simulation of heat flow in indexable insert drilling2024Ingår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 131, nr 9-10, s. 5177-5192Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In machining, the heat generated during the process deforms the components and the final shape might not meet specified tolerances. There is therefore a need for a compensation strategy which requires knowledge of the workpiece temperature field and the associated thermal distortions. In this work, a methodology is presented for the determination of the heat load for indexable insert drilling of AISI 4140. Compared to previous research, this work has introduced a varying heat load. The heat load is extracted from thermo-mechanical finite element simulations for different nominal chip thicknesses and cutting speeds using the coupled Eulerian-Lagrangian formulation of an orthogonal turning process. The heat load is then transferred to a simplified 2D axisymmetric heat transfer model where the in-process temperature field in the workpiece is predicted. To verify the methodology, the predicted temperatures are compared to the experimentally measured temperatures for various feed rates. It is found that the model is capable of predicting the workpiece temperatures reasonably well. However, the methodology needs to be further explored to validate its applicability.

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  • 2.
    Carrera Artola, Iosu
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Mondragon Unibertsitatea.
    Lucena Garcerán, Alejandro
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. University of Málaga .
    Detection of Frazil Ice at Water Intakes at Träbena Power Station2014Självständigt arbete på grundnivå (kandidatexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Frazil ice is a phenomenon that takes place in cold regions when the water of rivers, lakes or oceans is cooled under 0ºC. Several times during winter, frazil ice can appear at river Ätran, where Träbena hydropower plant is held by the company Wetterstad Consulting AB. Frazil ice particles contained in the flowing water are extremely sticky and adhere to any object placed in the water. Trash racks are used by the power plant at the water intakes to prevent any strange object to go into the turbines. However, frazil ice particles stick to the trash racks creating an ice blockage that interrupts the water inflow. In this situation, the power plant has to stop the production even for several months, due to the lack of water that reaches the turbines. In order to solve this problem, the company has installed a heating system on the trash racks that prevent the adhesion of frazil ice particles. This system is manually operated, and it is turned on or off based on the experience and predictions of the company. This heating system is very power consuming and every time it is turned on unnecessarily the company loses money. An automatic frazil ice detection system that turns on the heating system when needed is to be created. For that, several options have been analysed, and finally a capacitor-based sensor has been developed as a solution. The sensor consist of two steel plates coated with semi-transparent polycarbonate submerged underwater parallel placed in the space between the trash racks’ bars, forming this way a parallel plate capacitor. The capacitance of a capacitor depends exclusively on its geometry and the dielectric material between the plates. Hence when the water temperature is low enough, frazil ice particles stick to the plates of the capacitor and its capacitance will vary indicating that the accretion of frazil ice may block the water inflow. This variation is registered and a signal is send to the heating system to start operating. This way, the heating system is completely automated; no human intervention is needed at all.

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    Detection of Frazil Ice at Water Intakes at Träbena Power Station
  • 3.
    Furulind, Johan
    et al.
    Högskolan i Skövde, Institutionen för teknik och samhälle.
    Berg, Johan
    Högskolan i Skövde, Institutionen för teknik och samhälle.
    Feasibility Study for a Wind Power Project in Sri Lanka: a Minor Field Study2008Självständigt arbete på grundnivå (kandidatexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    This report covers a feasibility study for a wind power project in Sri Lanka. Three potential sites for a wind farm are presented, out of which the Ambewela Cattle Farm is chosen as the most suitable. Limitations of a wind farm at the site, due to properties of the electrical grid and logistical issues, are examined and costs related to installing the wind farm are estimated. The maximum capacity of a wind farm is calculated to 45 MW. The payback period of the wind farm is calculated to 4.4 years. Environmental benefits of the wind farm are estimated in terms of avoided CO2-emissions, which are calculated to 76 000 metric tonnes per year. The study concludes that a wind power project at the chosen site should be technically and financially feasible, if a wind turbine that matches certain logistical criteria can be found.

     

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  • 4.
    Karabulut, Mehmet
    et al.
    Department of Electrical and Computer Engineering, Yildirim Beyazit University, Ankara, Turkey.
    Kusetogullari, Huseyin
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningsmiljön Informationsteknologi. Department of Computer Science, Blekinge Institute of Technology, Karlskrona, Sweden.
    Kivrak, Sinan
    Department of Electrical and Electronic Engineering, Yildirim Beyazit University, Ankara, Turkey.
    Outdoor Performance Assessment of New and Old Photovoltaic Panel Technologies Using a Designed Multi-Photovoltaic Panel Power Measurement System2020Ingår i: International Journal of Photoenergy (Online), ISSN 1110-662X, E-ISSN 1687-529X, Vol. 2020, s. 1-18, artikel-id 8866412Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a new multi-photovoltaic panel measurement and analysis system (PPMAS) developed for measurement of atmospheric parameters and generated power of photovoltaic (PV) panels. Designed system presented with an experimental study evaluates performance of four new and four 5-year-old PV panel technologies which are based on polycrystalline (Poly), monocrystalline (Mono), copper indium selenide (CIS), and cadmium telluride (CdTe) in real time, under same atmospheric conditions. The PPMAS system with the PV panels is installed in Yildirim Beyazit University, Ankara Province, in Turkey. The designed PPMAS consists of three different subsystems which are (1) photovoltaic panel measurement subsystem (PPMS), (2) meteorology measurement subsystem (MMS), and (3) data acquisition subsystem (DAS). PPMS is used to measure the power generation for PV panels. MMS involves different types of sensors, and it is designed to determine atmospheric conditions including wind speed, wind direction, outdoor temperature, humidity, ambient light, and panel temperatures. The measured values by PPMS and MMS are stored in a database using DAS subsystem. In order to improve the measurement accuracy, PPMS and MMS are calibrated. This study also focuses on outdoor testing performances of four new and four 5-year-old PV panels. Average monthly panel efficiencies are estimated as 8.46%, 8.11%, 5.65%, and 3.88% for new Mono, new Poly, new CIS, and new CdTe PV panels, respectively. Moreover, average monthly panel efficiencies of old panels are calculated as 8.22%, 7.85%, 5.35%, and 3.63% in the same order. Test results obtained from the experimental system are also statistically examined and discussed to analyze the performance of PV panels in terms of monthly panel efficiencie

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  • 5.
    Ladrón de Guevara Muñoz, M. Carmen
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Martín Márquez, Javier
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Mini-grid system study applied to a stand-alone house located in Málaga, Spain2015Självständigt arbete på grundnivå (kandidatexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    A study of an off-grid photovoltaic system for the electrification of a stand-alone single residential house in a rural area located in the city of Málaga, Spain, is presented. The load of an average family house is analysed keeping in mind the available solar energy at this location. A preliminary sizing of the system is carried out considering predefined values for the efficiency of the different technologies employed in the system: photovoltaic (PV) array, batteries as energy storages, inverters to convert the energy obtained from the sun, and diesel gensets to ensure supply under any circumstances. Later, precise brands of the available technologies in the market are selected, and the system is re-sized using the new parameters. The life cycle cost of the mini-grid (MG) system shows that the amortization of the system in 20 years for a stand-alone house is not possible. Although it is not confirmed that 20 years will be sufficient to make the system profitable, other aspects are considered and discussed in terms of their feasibility in Málaga.

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  • 6.
    Linder, Jonas
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Kyleffektivisering av en havsvattenanläggning: Havets Hus i Lysekil2016Självständigt arbete på grundnivå (kandidatexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Havets Hus i Lysekil bedriver en anläggning med ett flertal havsvattenakvarium som innehåller fiskar och havsdjur från svenska havsvatten. Till anläggningen tas det kontinuerligt in nytt havsvatten från Gullmarsfjorden, till några av akva-rierna kyls det inkommande havsvattnet med hjälp av en kylmaskin. I dagsläget är kylmaskinen luftkyld, vilket är ineffek-tivt. Havets Hus vill undersöka möjligheten att effektivisera kylprocessen genom att kyla maskinen mer effektivt, undersö-ka om det går att ta vara på värmeenergin som annars släpps ut i luften eller på något annat sätt göra kylprocessen mer effektiv.Sex alternativ för effektivare kylning har tagits fram. Det finns två inriktningar på alternativen, antingen att förbättra den befintliga installationen genom att till exempel kyla dess kondensor mer effektivt med hjälp utav havsvatten eller att installera nya maskiner. Det finns också ett kompletteringsalternativ som går att kombinera med alla de andra alternativen och går ut på att installera en värmeväxlare mellan ingående havsvatten som ska kylas och utgående havsvatten från de kylda akvarierna. Alternativet som ger störst ekonomisk sparpotential går ut på att installera två nya kylmaskiner. En som är dimensionerad efter Havets Hus varmvattenbehov och som tar värme från det inkommande havsvattnet och en som fyller upp det resterande kylbehovet. De nya maskinerna fyller det totala kylbehovet på Havets Hus, det vill säga både kylbehovet för det inkommande havsvattnet och för ventilationssystemet. Alternativet kan spara Havets Hus ca 184 000-199 000 kr/år och tillsammans med en värmeväxlare kan det spara ca 202 000-223 000 kr/år.

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  • 7.
    Liu, Yu
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningsmiljön Virtuell produkt- och produktionsutveckling.
    Syberfeldt, Anna
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningsmiljön Virtuell produkt- och produktionsutveckling.
    Strand, Mattias
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningsmiljön Virtuell produkt- och produktionsutveckling.
    Applying Life Cycle Assessment to Simulation-Based Decision Support: A Swedish Waste Collection Case Study2020Ingår i: Advances and New Trends in Environmental Informatics: ICT for Sustainable Solutions: Conference proceedings / [ed] Rüdiger Schaldach; Karl-Heinz Simon; Jens Weismüller; Volker Wohlgemuth, Cham: Springer, 2020, Vol. 1, s. 165-178Konferensbidrag (Refereegranskat)
    Abstract [en]

    A method of integrating life cycle assessment into a simulation-based decision support system has been developed to help decision-makers take environmental impact into account during daily operations. The method was demonstrated in a real-world case study involving eight different trucks, which were selected and maintained by the case company. The trucks used different fuels, namely diesel, biodiesel, vehicle gas, and electricity. Compared to conventional diesel trucks, those using biodiesel emitted 37% less greenhouse gas (GHG) emissions. Gas trucks reduced GHG emissions by a further 40%. Overall, electric trucks have the lowest emissions. This paper also addresses the development of the methodology for this study. In particular, comparisons are made regarding the selection of different functional units and system activity mapping. Ways of achieving more accurate conclusions in future studies are discussed. 

  • 8.
    Lorente Zamora, Joanes
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Sorarrain Aguirrezabala, Gorka
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Modelling and emulation of industrial electric, pneumatic and hydraulic system2018Självständigt arbete på grundnivå (kandidatexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In recent years, the University of Skövde (HiS) is carrying an advance research in Virtual Commissioning and Emulation. The main goal of the research is to test and verify the control logic of an industrial system virtually before implementing it in the real industry. Literature shows how higher modeling detail level is needed taking into account aspects such as geometry, kinematic, behavior and interfaces. That makes an interesting branch of research for the university and that is the reason why the university is focusing on creating models in component level, where a complete emulation data model is being expanded. The aim of this thesis is to develop a way of modelling electric, hydraulic and pneumatic connections in order to create independent models that can be connected between them for creating systems. Furthermore, an energetic analysis of the system has been done. In the first part of the thesis, a frame of reference and a literature review has been done in order to learn about the fields that the authors are going to work. After that, the simulation models of different electric, pneumatic and hydraulic components have been created with a method, inspired by the producer/consumer concept, which provides a generic solution that allows energy flow in different domains between components in a simple way. Then, different component simulation models have been connected in order to emulate more complex systems. Once the models are done, there have been some test in order to know if all perform as expected. Finally, a discussion of the failures which have been during the project have been done. The experiments done have shown that the proposed and then implemented system has fulfilled all the objectives, unlocking the next step of the emulation development.

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  • 9.
    Mendoza, Ana Isabel
    et al.
    KTH-Royal Institute of Technology, Fibre and Polymer Technology, Stockholm, Sweden.
    Moriana, Rosana
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. KTH-Royal Institute of Technology, Fibre and Polymer Technology, Stockholm / SLU-Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Hillborg, Henrik
    ABB-Corporate Research, Power Technology, Västerås, Sweden.
    Strömberg, Emma
    KTH-Royal Institute of Technology, Fibre and Polymer Technology, Stockholm, Sweden.
    Super-hydrophobic zinc oxide/silicone rubber nanocomposite surfaces2019Ingår i: Surfaces and Interfaces, ISSN 2468-0230, Vol. 14, s. 146-157Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study presents comparative assessments on hydrophilic and hydrophobic ZnO nanoparticles and their deposition methods on the surface hydrophobicity of silicone rubber (PDMS) and glass substrates. The influence on the surface hydrophobicity and wettability of all the variables regarding the deposition methodologies and the interaction of the nanoparticles with the substrates were within the scope of this study. The different surfaces created by spraying, dipping and drop-pipetting deposition methods were assessed by static contact angle measurements and contact angle hysteresis from advancing and receding angles, as well as by the calculation of the sliding angle and the surface energy parameters. An accurate methodology to determine the contact angle hysteresis was proposed to obtain repetitive and comparative results on all surfaces. All the measurements have been correlated with the morphology and topography of the different surfaces analysed by FE-SE microscopy. The spray-deposition of hydrophobic ZnO nanoparticles on PDMS resulted in super-hydrophobic surfaces, exhibiting hierarchical structures with micro-and nanometer features which, together with the low surface energy, promotes the Cassie-Baxter wetting behavior. This study provides the fundamental approach to select critically the most promising combination in terms of materials and deposition techniques to create silicone-based super-hydrophobic surfaces with potential to be applied in high voltage outdoor insulation applications.

  • 10.
    Olmeda Noguera, Eduardo
    et al.
    Högskolan i Skövde, Institutionen för teknik och samhälle.
    Andrés Cervera, Santiago
    Högskolan i Skövde, Institutionen för teknik och samhälle.
    Bioclimatic House: Evaluation of solutions to develop a selfsustainable dwelling in Nordic countries2012Självständigt arbete på grundnivå (kandidatexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In  European  countries  houses  represents  36  %  of  CO 2   emissions.  To  reduce  these  emissions Bioclimatic  housing  is  proposed.  A  series  of  solutions  are  studied  in  this  project  to  acquire  a  low energy consumption building. Viability studies and guidelines of bioclimatic houses are given for the realization of this house in the Nordic countries.  A study of insulating materials and composition of the enclosures of the bioclimatic house is carried out  complying  with  the  Swedish  norm.  To  achieve  the  building  envelope  criteria  of  high  insulation and passive house construction are followed. Calculations of thermal transmittance, considering the geographical situation of the house, in a Nordic country, like Sweden are performed. One  method  to  obtain  the  energy  demand  of  buildings  is  to  use  computer  software.  A  graphic interface called DesignBuilder v 3.01. This software is utilized to study the importance of insulation and orientation in relation to the energy demand in a bioclimatic house. In  accordance  with  the  bioclimatic  construction,  renewable  energy  sources  are  chosen  to  supply electricity to the dwelling. This is to reduce the environmental impact and the ecological footprint of the household. To achieve this, three different alternatives are chosen. In addition, another goal is to study economic viability and possible agreements with an energy company in order to sell excess of energy.  A final result of the study and evaluation of the three different systems to provide energy and passive house strategies is obtained. According to the economic aspect, the Bioclimatic house should have a passive house envelope, facing south and a system combining of windmill turbine, solar photovoltaic panels and geothermal energy. The construction of bioclimatic houses helps to reduce the anthropogenic CO 2  emissions. In addition, the construction of bioclimatic houses is one way to achieve an ecologically sustainable future.

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  • 11.
    Samuelsson, Lina N.
    et al.
    KTH Royal Institute of Technology.
    Bäbler, Matthaus U.
    KTH Royal Institute of Technology.
    Moriana, Rosana
    KTH Royal Institute of Technology.
    A single model-free rate expression describing both non-isothermal and isothermal pyrolysis of Norway Spruce2015Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 161, s. 59-67Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A strictly isoconversional rate expression has been derived for pyrolysis of biomass. This rate expression, derived from non-isothermal thermogravimetric experiments using heating rates 2-10 K/min, can successfully predict the conversion rates of experimental data at heating rates 1-100 K/min and quasiisothermal experiments at 539-650 K. The methodology used is based on an extension of the incremental integral method by Vyazovkin (2001). Being able to derive an intrinsic reaction rate expression from non-isothermal data, without any assumption regarding the chemical processes present, opens up for the possibility to model industrial pyrolysis reactors, with a variety of temperature profiles.

  • 12.
    Samuelsson, Lina Norberg
    et al.
    KTH Royal Institute of Technology.
    Moriana, Rosana
    KTH Royal Institute of Technology.
    Bäbler, Matthäus U.
    KTH Royal Institute of Technology.
    Ek, Monica
    KTH Royal Institute of Technology.
    Engvall, Klas
    KTH Royal Institute of Technology.
    Model-free rate expression for thermal decomposition processes: The case of microcrystalline cellulose pyrolysis2015Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 143, s. 438-447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We explore the possibility to derive a completely model-free rate expression using isoconversional methods. The Friedman differential method (Friedman, 1964) and the incremental integral method by Vyazovkin (2001) were both extended to allow for an estimation of not only the apparent activation energy but also the effective kinetic prefactor, defined as the product of the pre-exponential factor and the conversion function. Analyzing experimental thermogravimetric data for the pyrolytic decomposition of microcrystalline cellulose, measured at six different heating rates and three different initial sample masses (1.5-10 mg), revealed the presence of secondary char forming reactions and thermal lag, both increasing with increased sample mass. Conditioning of the temperature function enables extraction of more reliable prefactors and we found that the derived kinetic parameters show weak dependence on initial sample mass. Finally, by successful modeling of quasi-isothermal experimental curves, we show that the discrete rate expression estimated from linear heating rate experiments enables modeling of the thermal decomposition rate without any assumptions regarding the chemical process present. These findings can facilitate the design and optimization of industrial isothermal biomass fed reactors.

  • 13.
    Spiliotis, Evangelos
    et al.
    Forecasting and Strategy Unit, School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece.
    Petropoulos, Fotios
    School of Management, University of Bath, Bath, United Kingdom.
    Kourentzes, Nikolaos
    Lancaster University Management School, Department of Management Science, Lancaster, United Kingdom.
    Assimakopoulos, Vassilios
    Forecasting and Strategy Unit, School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece.
    Cross-temporal aggregation: Improving the forecast accuracy of hierarchical electricity consumption2020Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 261, artikel-id 114339Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Achieving high accuracy in energy consumption forecasting is critical for improving energy management and planning. However, this requires the selection of appropriate forecasting models, able to capture the individual characteristics of the series to be predicted, which is a task that involves a lot of system and region level, not only the model selection problem is expanded to multiple time series, but we also require aggregation consistency of the forecasts across levels. Although hierarchical forecasting, such as the bottom-up, the top-down, and the optimal reconciliation methods, can address the aggregation consistency concerns, it does not resolve the model selection uncertainty. To address this issue, we rely on Multiple Temporal Aggregation (MTA), which has been shown to mitigate the model selection problem for low-frequency time series. We propose a modification of the Multiple Aggregation Prediction Algorithm, a special implementation of MTA, for high-frequency time series to better handle the undesirable effect of seasonality shrinkage that MTA implies and combine it with conventional cross-sectional hierarchical forecasting. The impact of incorporating temporal aggregation in hierarchical forecasting is empirically assessed using a real data set from five bank branches. We show that the proposed MTA approach, combined with the optimal reconciliation method, demonstrates superior accuracy, aggregation consistency, and reliable automatic forecasting. 

  • 14.
    Torosian, Rojé
    et al.
    Högskolan i Skövde, Institutionen för teknik och samhälle.
    Elmehag, Elin
    Högskolan i Skövde, Institutionen för teknik och samhälle.
    Life Cycle Assessment of an Ocean Energy Power Plant: Evaluation and Analysis of the Energy Payback Time with Comparison Between Sweden and Tanzania2013Självständigt arbete på grundnivå (kandidatexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    I dagens samhälle är energi av essentiell vikt. Energi behövs för transport, elektricitet och uppvärmning. Fossila bränslen, som är en begränsad resurs, är idag den dominerande energikällan som används. Allteftersom indu-strier och konsumenter världen över använder mer energi för vardag blir det allt viktigare att belysa hur viktigt det är att minska på den globala efterfrågan på energi. Fossila bränslen behöver ersättas med förnyelsebara energikällor, såsom sol-, vind- och tidvattenkraft, för att samhället ska uppnå en hållbar utveckling.När en ny produkt utvecklas är det viktigt att analysera den potentiella miljöpåverkan, förslagsvis genom att genomföra en livscykelanalys, innan tillverkningen tar vid. Deep Green, som är en enhet som drivs med hjälp av tidvatten varefter elektricitet genereras, är en produkt som befinner sig i ett initialt skede av produktutveckling-en. I den här rapporten har en livscykelanalys sammanställts på hela produkten med syftet att uppnå en analys av hur olika val av material påverkar energianvändningen, koldioxidutsläppen och energiåterbetalningstiden. Komponenter har jämförts med varandra för att fastställa vilken komponent hos Deep Green som bidrar mest till energianvändningen och koldioxidutsläppen. Utöver en livscykelanalys, LCA, har en digital modell, skapad i ett Excel dokument, utvecklats för att underlätta beräkningar av energianvändning, koldioxidutsläpp och ener-giåterbetalningstid. Den digitala modellen, med namn ENCO©, erbjuder möjlighet för användaren att ändra och definiera materialval för varje enskild komponent för att således utvärdera den potentiella miljöpåverkan samt energiåterbetalningstiden. Deep Green består av 34 olika komponenter som alla ingår i den genomförda LCAn men en initial analys visar att bara tolv specifika komponenter bidrar störst till energianvändningen och koldioxidutsläppen. Fundamentet och vingstrukturen står för 78 % respektive 15 % för energianvändningen samtidigt som tio andra komponenter tillsammans utgör sex ytterligare procent. Resterande 27 komponenter delar på den sista procenten. Givet materialen som företaget Minesto har bistått med uppgår den totala ener-gianvändningen och koldioxidutsläppen för hela produkten till ungefär 4500 GJ respektive 342 ton. Fundamen-tet är den del av Deep Green som bidrar mest till den potentiella miljöpåverkan.Beroende på de definierade materialen för varje komponent varierar energiåterbetalningstiden mellan 220 och 260 dagar vilket betyder att en produktion av Deep Green vore lönsam. Dock har den genomförda LCAn flera begränsningar som borde beaktas innan ett sista beslut fattas.Den resulterande energiåterbetalningstiden, EP, bör användas försiktigt och presenteras ihop med system grän-serna då de påverkar energiåterbetalningstiden mycket. Den totala energianvändningen och koldioxidutsläppen beror starkt på val av hantering när produkten är uttjänt. Baserat på resultatet, rekommenderas att fundamen-tet lämnas på havsbotten i slutet på livscykeln för att få lägst energiåterbetalningstid.En undersökning om huruvida det är möjligt att placera hela produktionskedjan i ett utvecklingsland, såsom Tanzania, har också blivit genomfört jämsides med LCAn. De flesta råmaterial, som är nödvändiga för tillverk-ning av Deep Green, bryts i Tanzania. Det är dessutom möjligt att importera de material som inte finns tillgäng-liga lokalt i landet. Med Tanzania som land kommer energiåterbetalningstiden att bli högre jämfört med Sve-rige eller England eftersom fler komponenter behöver importeras som i sin tur genererar en ökning av transpor-ter.När Deep green är färdigutvecklad rekommenderas att en ny beräkning av energiåterbetalningstid och koldiox-idutsläpp göras. ENCO© kan med fördel användas till detta. Det rekommenderas även att distributionskablar och installation inkluderas.

    Ladda ner fulltext (pdf)
    Life Cycle Assessment of an Ocean Energy Power Plant
  • 15.
    Trapero, Juan R.
    et al.
    Universidad de Castilla-La Mancha, Departamento de Administracion de Empresas, Ciudad Real, Spain.
    Kourentzes, Nikolaos
    Lancaster University, Department of Management Science, United Kingdom.
    Martin, A.
    Universidad de Castilla-La Mancha, Departamento de Administracion de Empresas, Ciudad Real, Spain.
    Short-term solar irradiation forecasting based on Dynamic Harmonic Regression2015Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 84, s. 289-295Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solar power generation is a crucial research area for countries that have high dependency on fossil energy sources and is gaining prominence with the current shift to renewable sources of energy. In order to integrate the electricity generated by solar energy into the grid, solar irradiation must be reasonably well forecasted, where deviations of the forecasted value from the actual measured value involve significant costs. The present paper proposes a univariate Dynamic Harmonic Regression model set up in a State Space framework for short-term (1-24h) solar irradiation forecasting. Time series hourly aggregated as the Global Horizontal Irradiation and the Direct Normal Irradiation will be used to illustrate the proposed approach. This method provides a fast automatic identification and estimation procedure based on the frequency domain. Furthermore, the recursive algorithms applied offer adaptive predictions. The good forecasting performance is illustrated with solar irradiance measurements collected from ground-based weather stations located in Spain. The results show that the Dynamic Harmonic Regression achieves the lowest relative Root Mean Squared Error; about 30% and 47% for the Global and Direct irradiation components, respectively, for a forecast horizon of 24h ahead. 

  • 16.
    Wigblad, Rune
    Strömstad akademi.
    En spaning på internationell massproduktion av perovskite solceller2024Rapport (Övrigt vetenskapligt)
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