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  • 1.
    Abd Alrahman, Chadi
    Högskolan Dalarna, Akademin Industri och samhälle, Elektroteknik.
    Evaluation of a PVT Air Collector2015Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Hybrid Photovoltaic Thermal (PVT) collectors are an emerging technology that

    combines PV and solar thermal systems in a single solar collector producing heat and

    electricity simultaneously. The focus of this thesis work is to evaluate the performance of

    unglazed open loop PVT air system integrated on a garage roof in Borlänge. As it is

    thought to have a significant potential for preheating ventilation of the building and

    improving the PV modules electrical efficiency. The performance evaluation is important

    to optimize the cooling strategy of the collector in order to enhance its electrical efficiency

    and maximize the production of thermal energy. The evaluation process involves

    monitoring the electrical and thermal energies for a certain period of time and investigating

    the cooling effect on the performance through controlling the air mass flow provided by a

    variable speed fan connected to the collector by an air distribution duct. The distribution

    duct transfers the heated outlet air from the collector to inside the building.

    The PVT air collector consists of 34 Solibro CIGS type PV modules (115 Wp for each

    module) which are roof integrated and have replaced the traditional roof material. The

    collector is oriented toward the south-west with a tilt of 29 ᵒ. The collector consists of 17

    parallel air ducts formed between the PV modules and the insulated roof surface. Each air

    duct has a depth of 0.05 m, length of 2.38 m and width of 2.38 m. The air ducts are

    connected to each other through holes. The monitoring system is based on using T-type

    thermocouples to measure the relevant temperatures, air sensor to measure the air mass

    flow. These parameters are needed to calculate the thermal energy. The monitoring system

    contains also voltage dividers to measure the PV modules voltage and shunt resistance to

    measure the PV current, and AC energy meters which are needed to calculate the

    produced electrical energy. All signals recorded from the thermocouples, voltage dividers

    and shunt resistances are connected to data loggers. The strategy of cooling in this work

    was based on switching the fan on, only when the difference between the air duct

    temperature (under the middle of top of PV column) and the room temperature becomes

    higher than 5 °C. This strategy was effective in term of avoiding high electrical

    consumption by the fan, and it is recommended for further development. The temperature

    difference of 5 °C is the minimum value to compensate the heat losses in the collecting

    duct and distribution duct.

    The PVT air collector has an area of (Ac=32 m2), and air mass flow of 0.002 kg/s m2.

    The nominal output power of the collector is 4 kWppv (34 CIGS modules with 115

    Wppvfor each module). The collector produces thermal output energy of 6.88 kWth/day

    (0.21 kWth/m2 day) and an electrical output energy of 13.46 kWhel/day (0.42 kWhel/m2

    day) with cooling case. The PVT air collector has a daily thermal energy yield of 1.72

    kWhth/kWppv, and a daily PV electrical energy yield of 3.36 kWhel /kWppv. The fan energy

    requirement in this case was 0.18 kWh/day which is very small compared to the electrical

    energy generated by the PV collector. The obtained thermal efficiency was 8 % which is

    small compared to the results reported in literature for PVT air collectors. The small

    thermal efficiency was due to small operating air mass flow. Therefore, the study suggests

    increasing the air mass flow by a factor of 25. The electrical efficiency was fluctuating

    around 14 %, which is higher than the theoretical efficiency of the PV modules, and this

    discrepancy was due to the poor method of recording the solar irradiance in the location.

    Due to shading effect, it was better to use more than one pyranometer.

  • 2.
    Abdi, Faisa
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Farah, Muse
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Energieffektivisering av Limatvätten AB: Värmeåtervinning från manglar2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Energieffektivisering är intressant för alla industrier, eftersom det handlar om minskning av både energianvändning och kostnad. Syftet med detta examensarbete är att analysera potentiell energiåtervinning av spillvärme från en mangel vid Limatvätten AB.

    Limatvätten AB är en stor och modern tvätterianläggning. Limatvätten tvättar åt främst hotell- och restaurangkunder. Limatvätten AB har egna textilier som hyrs ut till hotell, konferenser m.m. Största kunderna finns i Sälenfjällen och Siljansregionen.

    Då inga processdata fanns tillgängliga för detta arbete krävdes mätningar för att få basinformationen. Utifrån mätningar beräknas mängden av energi som kan återvinnas.

    Systemförslag för värmeåtervinning ges även i rapporten. Aquavent är en värmeväxlare som använder ventilationsvärme från manglar. Vattnet som värms upp i aquavent leds in i tvättrören, vilket leder till minskning av ångförbrukning i tvättprocesser. Temperaturförändring är beroende av värmeväxlarens verkningsgrad, ju högre temperaturförändring det är desto mer mängd av energiåtervinning fås.

    Efter identifiering av problemet kartlades tidsplan, lämpliga instrument samt intressanta parametrar. Fukthalten, temperaturen och dynamiska trycket har mätts. Formlerna som beskrivs i teoriavsnittet har använts till de flesta beräkningarna med hjälp av Excel.

    Av resultatet framkommer att maximala energibesparingen blir 184 MWh/år om all överskottsvärme från manglarna återanvänds. Utifrån resultatet blir den totala besparingspotentialen på 57 000 SEK/år. Ytterligare kompletterande mätningar och analyser behövs för att få tillräckligt bra beslutsunderlag. Men detta arbete tyder på att ytterligare analys är intressant. Resultaten visar det att finns potential att använda överskottsvärme från Limatvättens manglar. Förutom besparingen av energin så minskas också klimatpåverkan eftersom överskottsenergin återanvänds igen som annars skulle försvinna ut i atmosfären. Om två av manglarna kopplas med ett värmeåtervinningssystem, resulterar det en dubblering på besparingspotentialen.

    För att få ett mera noggrant resultat kunde man logga en längre tid för mätningarna för att se förändring kring de mätande storheterna t.ex. genom att installera mätare som loggar till en dag eller till med en vecka. Övervakning och tolererande givare behövs dock.

  • 3.
    Abrahamsson, Jonas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lindqvist, Jakob
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Nedsmutsade värmesystems påverkan på energisystemet: Effektivisering vid användning av rengöringsmetoder2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Nedsmutsning av värmesystem är ett icke välkänt problem som kan få stora ekonomiska konsekvenser. På grund av mineraler och lågt pH-värde i systemet uppkommer kalkavlagringar och korrosion som kan täppa igen systemet och kan skada komponenter. Detta kommer resultera i en ökad energianvändning för användare och en högre tillförd energi från fjärrvärmeproducenten. Syftet med arbetet är att studera olika metoder för rengöring av värmesystem och om det är lönsamt med rengöring av värmesystem. Rengöringens effekt på fjärrvärmebehovet och hur det påverkar växthusgasutsläppet och primärenergianvändningen. Samt undersöka om underhåll av värmesystemet ger mindre energianvändning än att bygga om klimatskalet. Tidigare studier inom området undersöktes och relevant data samlades in efter samtal med intressanta företag som arbetar med rengöring av värmesystem. Rengöring av värmesystemen jämfördes med olika åtgärdspaket som ombyggnad av klimatskalet och värmeåtervinning av ventilation. Rengöring av värmesystemet med en effektivisering på 10 % gav ett minskat fjärrvärmebehov på 1,63 GWh per år samt ett minskat utsläpp på 177 ton CO2e per år. Det minskade fjärrvärmebehovet gav en minskad primärenergianvändning med 113 750 kWh per år. Installation av rengöringssystem kan ge Tunabyggen en besparing på 759 200 kr per år för hela Tjärna Ängar. Slutsatsen med arbetet är att rengöring förlänger värmesystems livslängd men kan inte ersätta ombyggnation av klimatskalet när det gäller minskad energianvändning.

  • 4.
    Abreu Saraiva Freitas, Iuri
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Indoor climate: A comparison of residential units in Tjärna Ängar, Borlänge before and after retrofitting2018Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This study try to understand which aspects were fundamental to indoor climate and how to obtain them in order to provide the best possible experience in the thermal comfort of individuals. Thus, arose the studies of Fanger, which was the seed for a new era of discoveries in the area and founded the knowledge our society have today in this globally used standards and norms. Referring to these fundamental aspects of the indoor comfort, data collection was taken in situ to show in details what was happening. This study was executed in order to demonstrate the differences between the data previous and after a process of retrofitting in dwellings built in the 60s and 70s of the century past, in the district of Tjärna Ängar, Borlänge, Sweden. The comparative results using criteria such as Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD), Draft Rate (DR), air velocity, Mean Radiant Temperature (MRT), Relative Humidity (RH) and air temperature, showed an improvement in 6 of the 8 parameters analyzed. Confirming the expectation that through the retrofitting the residents will be more satisfied, obtain better quality of indoor climate comfort and also increase occupied area in these dwellings.

  • 5.
    Ahamed, Anees
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Accelerated Aging of First-surface Enhanced Aluminum Solar Reflectors under Damp Heat Conditions2016Självständigt arbete på avancerad nivå (masterexamen), 25 poäng / 37,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Solar reflectors are one of the main components of concentrating solar power systems. With new products being developed, durability studies become a necessity for assessing the feasibility of commercial application. In this project, accelerated aging of three types of first-surface enhanced aluminum reflectors and one type of second-surface silvered thick glass mirror under damp heat conditions is studied. The project is conducted at the Plataforma Solar de Almería (PSA), in collaboration with German Aerospace Center (DLR), and Center for Energy, Environment and Technology (CIEMAT), Spain.

     

    The study is centered on analyzing the effect of soiling on degradation of reflectors. In addition to conventional methods, space resolved specular reflectometry is utilized for comparative purpose. Damp heat test conditions are simulated in a climatic test chamber. Test is conducted with reference to International Electrotechnical Commission standard IEC 62108 10.7a: damp heat test guidelines. The reflector samples are artificially soiled with natural and synthetic test sands of varying composition. Reflector performance is assessed based on the reduction in monochromatic specular reflectance.

     

    From the tests, a comparative assessment of the candidate reflectors is obtained. Aluminum samples suffered higher degradation than silvered glass mirrors. Aluminum reflectors with polymer top coat permanently retained soil residue. It is observed that presence of chlorides and organic components caused corrosion on all the types of reflectors tested. Surface roughening is the reason for performance deterioration in most of the cases. By comparing different reflectance measurement methods, the significance of total area of the measurement spot in the measurement procedures could be highlighted. It is suggested that for studies involving artificial soiling, the grain size of sand is to be factored in.

  • 6.
    Ahmadi Moghadam, Parham
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Steel Sheet Applications and Integrated Heat Management2016Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Increasing energy use has caused many environmental problems including global warming. Energy use is growing rapidly in developing countries and surprisingly a remarkable portion of it is associated with consumed energy to keep the temperature comfortable inside the buildings. Therefore, identifying renewable technologies for cooling and heating is essential. This study introduced applications of steel sheets integrated into the buildings to save energy based on existing technologies. In addition, the proposed application was found to have a considerable chance of market success.

    Also, satisfying energy needs for space heating and cooling in a single room by using one of the selected applications in different Köppen climate classes was investigated to estimate which climates have a proper potential for benefiting from the application. This study included three independent parts and the results related to each part have been used in the next part.

    The first part recognizes six different technologies through literature review including Cool Roof, Solar Chimney, Steel Cladding of Building, Night Radiative Cooling, Elastomer Metal Absorber, and Solar Distillation. The second part evaluated the application of different technologies by gathering the experts’ ideas via performing a Delphi method. The results showed that the Solar Chimney has a proper chance for the market.

    The third part simulated both a solar chimney and a solar chimney with evaporation which were connected to a single well insulated room with a considerable thermal mass. The combination was simulated as a system to estimate the possibility of satisfying cooling needs and heating needs in different climate classes. A Trombe-wall was selected as a sample design for the Solar Chimney and was simulated in different climates. The results implied that the solar chimney had the capability of reducing the cooling needs more than 25% in all of the studied locations and 100% in some locations with dry or temperate climate such as Mashhad, Madrid, and Istanbul. It was also observed that the heating needs were satisfied more than 50% in all of the studied locations, even for the continental climate such as Stockholm and 100% in most locations with a dry climate. Therefore, the Solar Chimney reduces energy use, saves environment resources, and it is a cost effective application. Furthermore, it saves the equipment costs in many locations. All the results mentioned above make the solar chimney a very practical and attractive tool for a wide range of climates.

  • 7.
    Aishwarya, Veena Aishwarya
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Effects of Soling on the Solar Radiation Sensors for Indian Climatic Conditions2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The satisfaction and elation that accompany the successful completion of any task

    would be incomplete without the mention of the people who have made it possible. It is a great

    privilege to express my gratitude and respect to all those who have guided me and inspired me

    during the period of the project work.

    First and foremost, I express my sincere gratitude to my University professor

    Fiedler Frank, Program Coordinator, Dalarna University, Borlange, Sweden who encouraged

    and permitted me to have my project in the second semester itself.

    I owe a lot to my supervisor Rönnelid Mats, Associate Professor of Energy and

    Environmental Technology, Dalarna University, Borlange, Sweden for his valuable

    suggestions, constructive criticism and encouragement for the project.

    I deem it to be a great privilege in thanking my external supervisor Dr.Richard

    Meyer, Founder and Managing Director (Suntrace GmbH) and Marko Schwandt, Advisor, Solar

    Expert en Suntrace GmbH for giving an opportunity to work under him. Their guidance,

    academic freedom and co-operation have helped me in completing my project.

    My heartfelt thanks to Dr. S. Gomathinayagam, Director General, NIWE and Dr.G.Giridhar,

    Deputy Director General & Head, SRRA department, NIWE for providing me the necessary

    facilities for the completion of my masters project. I am indebted to Dr.Indradip Mitra,Senior

    Technical Advisor at GIZ GmbH and Kaushal Chhatbar, Project Manager, Project

    Development at Suntrace GmbH , for their valuable suggestions and support.

    I also pay my sincere regards to the staffs of SRRA department for their support

    during the period of my project. I owe a lot to my family, who always motivated me and brought

    me to this level. Finally I submit my obeisance to THE ALMIGHTY for constantly supporting

    me and blessing me with the necessary strength to carry out this research.

  • 8.
    Alayan, Sophia
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Design of a PV-Diesel Hybrid System with Unreliable Grid Connection in Lebanon2016Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis is a study on integration of photovoltaic generators into an existing diesel-unreliable grid connected system at the Lebanese village of Khiam. The main goal of implementing PV-diesel hybrid system is to reduce diesel consumption and the import of fossil fuel used in electricity power supply. Before designing the system, it is necessary to create a load profile for 120 households and pre-design the size of the PV generator, the capacity of storage system and inverter type/size selection. The load profile data is based on the average of monthly energy consumption gathered from Khiam village households.

    Detailed simulations and financial analysis are performed with HOMER to compare different systems and their viability. The simulations include four different designs starting from the existing system, diesel generator with unreliable grid, followed by PV generator and unreliable grid, PV and diesel generator and ended with the complete hybrid system. Once the Hybrid system is determined a detailed design is done to optimize the lowest cost PV-diesel hybrid system. The final simulated PV-diesel hybrid system is suggested with a PV capacity of 270 kWp, existing diesel capacity with 200 kVA, an inverter output of 115 kW and battery bank nominal capacity is 1872 kWh. The system renewable fraction is 53% and the project life cycle is 25 years. The PV-diesel hybrid system is projected to produce electricity at a cost of 0.12 USD/kWh. This cost is significantly lower than the 0.26 USD/kWh paid to the diesel operator, as well as lower than 0.13 USD/kWh paid to the utility grid.

    In addition, and according to the given information from the owner, an estimated diesel consumption of 104000 ltr/year, the simulation result shows diesel consumption at 40000 ltr/year. The reduced carbon dioxide production by 65%, from 776 to 272 tons per year, provides further justification for the PV installation in a commercial PV-diesel hybrid system.

  • 9.
    Alfadel, Usama
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Analysing the Peak Shaving Effect and the Increase in SelfConsumption and Self Sufficiencyof Battery Storage When Coupledto a Single Family House2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The aims of the study were to investigate the increase in self-consumption and self-sufficiency and the peak shaving effect of batteries when added to a PV system dimensioned to supply the electric demand of a low energy house built in Sweden. The simulated batteries were Li-ion and the study had a 15-minutes temporal resolution. The study took only the technical aspect of batteries into account and disregarded the economic aspect. A data set of measurements from two near-zero-energy houses built by the Research Institute of Sweden (RISE) was used as inputs. The first house provided measured load profile for an automated load and measured PV production from its 3.6 kW

    p system, the second house provided a load profile for a normal human interactive load. The measured PV production from the 3.6 kWp PV system was compared to the PV production from a simulated 3.6 kWp system taken from PVsyst and System Advisor Model (SAM) and by using different weather data profiles for the simulations. The global irradiance values from the used weather profile data were compared to demonstrate the difference in its values and its effect on the simulated PV production. This comparison between the measured PV production and the simulated one was done because most of the PV simulation software does not take measured PV production as input but they simulate their own PV production based on their built-in weather data; including the software used in this study SAM. The first house with the automated load had an annual energy consumption of Ca. 3600 kWh / Year. The second house with its human interactive load had an annual energy consumption of Ca. 6000 kWh / Year. The load profile was taken as a whole and then divided to different types; heat pump, ventilation and remaining load which represents house hold services. The effect of the input load profile types and its temporal resolution was clarified; this effect came in consistency to what was concluded from the literature review. Different simulations were done varying battery sizes, voltage level, coupling method, dispatch algorithm and other parameter. Three different dispatch algorithms were used for the simulations; two are designed for peak shaving and are built-in tools in SAM while the third algorithm is called Target Zero and designed for maximizing self-consumption and self-sufficiency, it was found in a reference so it was executed in MS Excel. Each of the algorithms used was found to affect both the peaks and the self-consumption and self-sufficiency of the system after adding the batteries compared to before, one as a major effect and the other as a byproduct effect. The peak shaving results varied by varying the batteries and the dispatch algorithm used, for the peak shaving algorithms from SAM, a general decrease in peaks value was reached. For the Target Zero algorithm which optimizes on self-consumption and self-sufficiency, a decrease in the number of the peaks was reached. Both decreases happened by increasing battery sizes. For the self-consumption and self-sufficiency effect, an increase happened with its highest value for 7.2 kWh batteries and by using the three different algorithms. The effect of the load type was also demonstrated by comparing the simulations results for the heat pumps from both houses since both heat pumps were found to have the highest effect on the results. The study was concluded by emphasizing the added values of batteries when coupled to a behind-the-meter PV system. The study could have been more precise and added more information to this field if it had a 1 minute temporal resolution simulations, but patching one minute temporal resolution load profile takes a long time. Working with one minute load profile requires one minute weather profile for the PV simulation which is normally only commercial. Also, having a weather station installed at the house to measure the solar irradiance to be used in the simulation instead of using different weather profiles would have added more accuracy to this paper.

  • 10.
    Alhamwi, MHD Mouaz
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Evaluating the Economic Feasibility for utilizing PV Power Optimizers in Large-scale PV Plants for The Cases of Soiling, Mismatching, and Degradation2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The solar PV modules are influenced by a variety of loss mechanisms by which the energy yield is affected. A PV system is the sum of individual PV modules which should ideally operate similarly, however, inhomogeneous soiling, mismatching, and degradation, which are the main focus in this study, lead to dissimilarities in PV modules operating behavior and thus, lead to losses which will be assessed intensively in terms of energy yield.

    The dissimilarities in PV modules are referred to the ambient conditions or the PV modules

    characteristics which result in different modules’ maximum power point (MPP) and thus, different currents generated by each PV modules which cause the mismatching. However, the weakest PV module current governs the string current, and the weakest string voltage governs the voltage.

    Power optimizers are electronic devices connected to the PV modules which adjust the voltages of the PV modules in order to obtain the same current as the weakest module and thus, extract

    the modules’ MPP. Hence, the overall performance of the PV plant is enhanced. On the other hand, the power optimizers add additional cost to the plant’s investment cost and thus, the extra energy yield achieved by utilizing the power optimizers must be sufficient to compensate the additional cost of the power optimizers. This is assessed by designing three systems, a reference system with SMA inverters, a system utilizes Tigo power optimizers and SMA inverters, and a system utilizes SolarEdge power optimizers and inverters. The study considers four different locations which are Borlänge, Madrid, Abu Dhabi, and New Delhi.

    An Excel model is created and validated to emulate the inhomogeneous soiling and to evaluate the economic feasibility of the power optimiz

    ers. The model’s inputs are obtained from PVsyst and the precipitation data is obtained from Meteoblue and SMHI database.

    The economic model is based on the relation between Levelized Cost of Electricity (LCOE) which will be used to derive the discount rate. Graphs representing the discounted payback period as a function of the feed-in tariff for different discount rates is created in order to obtain the discounted payback period.

    The amount of extra energy yielded by the Tigo and the SolarEdge systems is dependent on the soiling accumulated on the PV modules. Relative to the reference system, 6.5 % annual energy gain by the systems utilizing the power optimizers in soiling conditions, up to 2.1 % in the degradation conditions, and up to 9.7 % annual energy gain at 10 % mismatching rate. The extra energy yield is dependent on the location, however, the Tigo and the SolarEdge systems have yielded more energy than the reference system in all cases except one case when the mismatch losses is set to zero.

    The precipitation pattern is very influential, and a scare precipitation leads to a reduction in the energy yield, in this case, the Tigo and the SolarEdge systems overall performance is enhanced and the extra energy gain becomes greater.

    The Tigo system yield slightly more energy than the SolarEdge system in most cases,

    however, during the plant’s lifetime, the SolarEdge system could become more efficient than the Tigo system which is referred to the system’s sizing ratio. The degradation of the system or the soiling accumulation decreases the irradiation and thus, a slightly oversized PV array become suitable and deliver an optimal power to the inverters.

    The SolarEdge system is feasible in all scenarios in terms of LCOE and discounted payback period, although its slightly lower performance relative to the Tigo system, this is referred to its low initial cost in comparison to the other systems. The Tigo system is mostly infeasible although it yields more energy than the reference and the SolarEdge systems, this is referred

    iii

    to its relatively high initial cost. However, feed-

    in tariffs higher than 20 € cent / kWh make

    all systems payback within less than 10 years.

    The results have overall uncertainty within ± 6.5 % including PVsyst, Excel model, and the

    precipitation uncertainties. The uncertainty in the degradation and the mismatching

    calculations is limited to PVsyst uncertainty which is ± 5 %. The uncertainties in LCOE in

    the location of New Delhi, since it is the worst-case scenario, are 5.1 % and 4 % for the

    reference and the systems utilizing power optimizers, respectively.

    Consequently, accommodating the uncertainties to the benefits gained by utilizing power

    optimizers indicates that the energy gain would oscillate in the range of 6 % - 6.9 % for the

    soiling calculations, 2 % - 2.2 % for the degradation simulations, and 9.2 % - 10.2 % for the

    mismatching simulations at 10 % mismatchrate.

  • 11.
    Al-Hashimi, Mazin
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Modelling Installation Cost for Rooftop PV Systems2015Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The cost of installation of photovoltaic (PV) systems is a substantial fraction of the total cost of the project and the same is increasing with reducing cost of PV modules. This study essentially deals with the cost of installation of rooftop PV systems and presents a cost model for it, based on data collected for more than 700 projects of different capacities, roof types, circumstances, and locations in Sweden. The presented cost model shall give reasonably accurate estimations about the costs associated with the main elements of the process of rooftop PV systems installation, such as labour, shipping, equipment, travel, and accommodation, for different situations as a function of few important variables such as system capacity, roof type, distance to the installation location, etc. The weighted share of cost of the different elements of the cost model out of the total cost of installation was determined. Several relationships between different elements and variables were examined to find relationships that can help to better understand the process of installation and to develop the cost model. The variations in time required per unit system capacity have been examined for several processes of rooftop PV systems installation, to investigate about potential for reduction in the time and thus the cost due to economies of scale.

  • 12.
    Alkhado, Luqman
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Boussaa, Youcef
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Heat transfer tests on EPS material and massive timber wall component2018Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Timber walls are known to be an energy efficient component in the building envelope.

    These building elements are essential in the passive design and have been pointed out to

    their ability to regulate the indoor climate and reduce energy demand. Heat transfer

    measurements of thermal transmittance value of Iso-timber wall component have been

    performed with the climate chamber at three temperature differences. The influence of

    temperature variations on the thermal conduction of the wall were investigated. The

    temperature on the warm side was kept at room temperature 20 °C while the cold side

    temperature was decreased from 0 C to -20 C during the tests. As the temperature

    difference is increased, the thermal transmittance value of the timber wall component

    decreased slightly due to decrease in the thermal conductivity value. The effect of density

    and porosity on the thermal conductivity may be related to the presence of air voids and

    cell boundaries inside the timber wall. Results have showed that the U-value of the timber

    wall component decreases at higher temperature differences which indicates the higher

    degree of insulation of the timber wall component.

  • 13.
    Almsalati, Hussam
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Life cycle assessment of villas made by Fiskarhedenvillan, comparison between wood and brick facade2018Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Awareness of climate change has resulted in enormous challenges for developed and

    developing countries. The frightening truth about our environmental situation has led to

    investigations of the causes of these changes and to obstruct these sources gradually but

    quickly. The alarming increase of average temperature of the earth has caused much worry

    around the world. Gas emissions in the atmosphere greatly affect the environment, where

    CO

    2 emissions is one of the most serious factors contributing to the global warming

    potential. As the building sector emits 40% of global energy use and one-third of global

    greenhouse gas emissions, engineers must be educated to choose the best materials that

    lead to reducing CO

    2 emissions. This means selecting materials that have less negative

    impact on the environment and are more “environmentally friendly”.

    This study shows how much CO

    2e emissions are released into the atmosphere from a

    wooden structure villa that consists of two stories, a storage and a garage, with a total area

    of 229.6m2. The results of this case will be compared to a second case, where the external

    wooden siding is replaced with brick veneer. This result of this comparison provides us

    with a guideline in for how the selected materials impact the environment, illuminating the

    importance in choosing the right materials according to their CO

    2e emission levels. In this

    way, the building sector can actively work to reduce the environmental impact.

    To achieve these goals, this study performed via life cycle assessment LCA methodology

    by using the One-Click LCA program. LCA is identified as a technique to assess the

    environmental impact and resources used through a product’s life cycle. This study utilized

    the LCA methodology (cradle to grave), which means starting from the extraction of raw

    materials, to product production, manufacturing, product usage and its end of life. The

    study lifespan was estimated to be 50 years.

    The results of the study verify that the wooden villa is more environmentally friendly than

    the villa made of brick, where carbon dioxide equivalent emission can be reduced to more

    than half by utilizing wood. Implementing the life cycle assessment study to any building

    aids in making the decision to choose the right materials for building according to CO

    2e

    emission. And in this way, the environmental impact caused by the building sector will be

    greatly reduced.

  • 14.
    Almsalati, Hussam
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Life cycle assessment of villasmade by Fiskarhedenvillan, comparison between wood and brick facade2018Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Awareness of climate change has resulted in enormous challenges for developed and developing countries. The frightening truth about our environmental situation has led to investigations of the causes of these changes and to obstruct these sources gradually but quickly. The alarming increase of average temperature of the earth has caused much worry around the world. Gas emissions in the atmosphere greatly affect the environment, where CO2 emissions is one of the most serious factors contributing to the global warming potential. As the building sector emits 40% of global energy use and one-third of global greenhouse gas emissions, engineers must be educated to choose the best materials that lead to reducing CO2 emissions. This means selecting materials that have less negative impact on the environment and are more “environmentally friendly”.

    This study shows how much CO2e emissions are released into the atmosphere from a wooden structure villa that consists of two stories, a storage and a garage, with a total area of 229.6m2. The results of this case will be compared to a second case, where the external wooden siding is replaced with brick veneer. This result of this comparison provides us with a guideline in for how the selected materials impact the environment, illuminating the importance in choosing the right materials according to their CO2e emission levels. In this way, the building sector can actively work to reduce the environmental impact.

    To achieve these goals, this study performed via life cycle assessment LCA methodology by using the One-Click LCA program. LCA is identified as a technique to assess the environmental impact and resources used through a product’s life cycle. This study utilized the LCA methodology (cradle to grave), which means starting from the extraction of raw materials, to product production, manufacturing, product usage and its end of life. The study lifespan was estimated to be 50 years.

    The results of the study verify that the wooden villa is more environmentally friendly than the villa made of brick, where carbon dioxide equivalent emission can be reduced to more than half by utilizing wood. Implementing the life cycle assessment study to any building aids in making the decision to choose the right materials for building according to CO2e emission. And in this way, the environmental impact caused by the building sector will be greatly reduced.

  • 15.
    Al-Samahiji, Alexander
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Incorporating Solar Energy Into an Aluminium Smelter’s Energy Mix: A study using Aluminium Bahrain2017Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis was aimed at studying the possibility of integrating solar energy in to an existing aluminium smelter in the Kingdom of Bahrain owned by Aluminium Bahrain (ALBA). The smelter was powered by its own in-house natural gas fed power plants. ALBA was chosen as the subject of the study for of two reasons. Firstly, the power station at ALBA was similar in technology to those powering the national grid. Secondly, the nominal power of ALBA was not dissimilar to that of the national grid. This meant that the techniques and technologies investigated were useful in the context of the national grid as well. A literature review was initially conducted to better understand how the current aluminium smelters work, what the possibilities were for introducing solar energy and what has been done previously. The study used publically available information to deduce the energy consumption of the ALBA smelter on an annual basis. For the year 2011 this was found to be in the order of 15.2TWh when ALBA had 2,249MW of nominal plant capacity installed and had consumed about 132MMBCF of natural gas. With the planned pot-line 6 expansion an additional 1,792MW capacity would be added with the corresponding additional gas use and increased energy output. The completion of pot-line 6, scheduled for Q1 2019, would also make ALBA the world’s largest single-site aluminium smelter.  This energy demand information was then used with PVSyst and System Advisor Model simulation software. The aim was to determine what photovoltaic (PV) and concentrated solar power (CSP) energy plants capable of meeting ALBA’s needs would be in terms of power, energy outputs and land usage. Although powering a modern aluminium smelter is possible with today’s solar technology, the area of land required would be very large. It was deduced that using PV fixed tilt arrays, a PV plant of 9.2GWp would be required to deliver the annual energy requirements of ALBA covering a theoretical land area of some 200km2. Utilising CSP plants of central tower and concentric heliostat design would need about 358km2 whereas parabolic trough collector technology would need about 240km2. However a CSP plant utilising linear Fresnel collectors would need about 105km2 of land area. These contiguous land areas are not available in the Kingdom of Bahrain and so alternatives would have to be studied for locating such plants. Another issue would be to find a robust and reliable storage technology to power the plant during the evenings and other times of low solar resource.  It was found that the existing roof areas of ALBA’s pot-lines and cast house would be sufficient to house a PV plant of 6.5MWp utilising standard 250Wp PV modules. This would be larger than the largest plant currently installed in the country which stands at 5MWp developed by Bapco. The plant would produce some 9.7GWh of energy per average year and could be utilised by ALBA. Alternatively, the PV plant could be connected directly to the national grid and thus provide another source of income to ALBA whilst helping in the national drive for harnessing renewable energy. It should be noted that there are more suitable roof areas available at ALBA meaning that the PV plant size could be larger and if more powerful modules are used, the nominal plant capacity would also be increased delivering more annual energy. Due mainly to time constraints, it was not possible to investigate some areas that were highlighted during the course of the study. These included plant costs, energy storage options, modelling and simulating CSP derived heat injection into gas power turbines, water usage requirements and mitigation techniques and the technologies for maintaining the collectors clean and reflective in the harsh desert climate of the country. These are all areas for further work.

  • 16.
    Alzén, Axel
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Effektivisering av en produktionsprocess: Analys och förbättringsförslag till en verkstadsindustri2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Isakssons AB tillverkar specialdesignade produkter och effektiva lösningar inom rostfritt, byggplåt och miljöteknik. För tillfället befinner sig företaget i en expansionsfas, vilket ställer större krav på företagets produktion. För att klara av utvecklingen som Isakssons genomgår så har de valt att utföra en ombyggnation av sina lokaler, och dessa måste anpassas för produktionen för att möjliggöra vidare expansion av verksamheten.  Syftet med denna studie är att ge förbättringsförslag till en effektivare produktionsprocess hos ett tillverkande företag med varierande produkter. För att skapa förståelse för produktionsprocessen har flödesscheman, processkartläggningar och tidsstudier utförts. Genom utförandet av en nulägesanalys har förbättringsmöjligheter identifierats, och förändringar har föreslagits utifrån dessa.  Resultatet av frekvensstudierna visar att operatörerna lägger mycket tid på arbete som inte är direkt relaterat till tillverkning av produkter, dvs icke värdeskapande aktiviteter. Genom att skapa flera arbetsstationer för tillverkning samt införa visuella hjälpmedel på arbetsplatsen så kan dessa aktiviteter minskas. Dessutom har förflyttningar av flera av verkstadens maskiner och lager utförts, för att skapa ett enklare flöde genom lokalen.

  • 17.
    Andersson, Carolin
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Från oljehydraulik till vattenhydraulik: Utveckling av ett portabelt hydraulikaggregat2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Rapporten beskriver arbetet bakom utvecklingen av ett portabelt vattenhydrauliksystem som ska användas till att öppna och stänga en dammlucka om det ordinarie hydrauliksystemet som används till detta är ur funktion. Syftet var att uppnå samma prestanda som ett portabelt oljehydrauliksystem vilket också gick att åstadkomma med undantaget att olja inte gick att undvika helt.

    Arbetet utfördes i samarbete med företaget Mobin Hydraulic AB som utvecklar hydrauliska system för att öppna och stänga dammluckor. Mobin är specialiserade på vattenhydraulik som är ett mer miljövänligt alternativ i jämförelse med oljehydraulik. Eftersom ett intresse också fanns på marknaden där miljövänliga lösningar efterfrågades allt mer var det portabla vattenhydrauliksystemet av intresse för både Mobin och för marknaden.

    Problematiken i arbetet kretsade kring hur flödet skulle styras och vilken pump och hydraulmotor som kunde användas i systemet. Komponenterna skulle vara anpassade för vatten och harmoniera med en förbestämd bensinmotor samtidigt som önskad prestanda levererades.

    Genom att studera hydraulik och vattnets egenskaper och påverkan på det hydrauliska systemet i kombination med att ta del av Mobins erfarenheter skapades en bild över systemets uppbyggnad och vilka komponenter som önskades.

    Utifrån en komponentsökning, utförda beräkningar och genom en konceptutformning gjordes ett konceptval där de valda komponenterna, komponenternas dimensioner och placeringar i systemet framgick. Till följd av den begränsade tillgången på komponenter inom vattenhydrauliken användes växellådor för att få ut rätt varvtal och moment. En av växellådorna innehöll olja och därför gick det inte att undvika oljeanvändningen helt.

  • 18.
    Andersson, David
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Effektiviserad balresthantering2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Arctic Paper Grycksbo är ett företag som tillverkar papper med inköpt pappersmassa. Denna pappersmassa anländer till företaget i form av massabalar, inslagna i ett så kallat omslagspapper som även det går att använda för att tillverka papper. Skador på balar till följd av transport och hantering gör att användbar pappersmassa avlägsnas från balen och hamnar på marken. Papperet plockas upp och placeras i en återvinningscontainer av de som arbetar på massamottagningen. Containern ska sedan tömmas och återvinnas.

    Då den nuvarande återvinningsrutinen visat sig behöva ekonomisk och ekologisk förbättring, så finns ett behov av att antingen förbättra metoden/rutinen för att återvinna papperet, eller att förhindra att balresterna lossnar. Syftet med arbetet är att ta reda på vilka möjligheter som finns till förbättring.

    Kartläggning och beräkningar av återvinningspotentialer och kostnader för nuvarande sättet att ta hand om balresterna har därför tagits fram. Dessa ligger till grund för vart störst förbättringspotential finns och baserat på denna så har olika konceptförslag tagits fram.

    Med hjälp av resultatet från kartläggningen har ett nytt sätt att hantera återvinningen av papperet tagits fram i samråd med tekniker på företaget. Den nya metoden möjliggör ett sätt att förenkla den nuvarande rutinen och minska kostnaderna samt underlätta för de involverade.

  • 19.
    Andersson, Grober
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Framdrivningssystem för Articulated Funiculator i SL deep station: Framtagning och urval av koncept2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Det här examensarbetet har genomförts i samarbete med Tyréns i projektet Articulated Funiculator som utvecklar framtidens vertikala transportsystem som i det här fallet är tänkt att användas i SL deep station i Stockholm.Syftet med det här arbetet är att är att ta fram framdrivningskoncept för Articulated Funiculator och genom konceptval sortera ut det optimala för SL deep station. För att nå syftet har studier företagits av litteratur samt rapporter som följts av workshops och kundundersökningar. Sedan har en parvis jämförelse gjorts, QFD, konceptgenerering och ett tvåstegs konceptval genomförts.Resultat är att det optimala framdrivningssystemet för SL deep station i Stockholm är ett system med linjärmotorer som är monterade mellan spåren.

  • 20.
    Andersson, Martin
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Konceptutvärdering av gjutformshantering: Utformning och dimensionering av entresolplan enligt eurocode2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Vid ABB Components i Ludvika tillverkas genomföringar till transformatorer. Under tillverkningen av dessa genomföringar används ett antal gjutformar. Gjutformarna lagras på ett entresolplan uppbyggt av ett antal pelare och balkar. Mängden gjutformar ökar och har lett till att nuvarande sätt att hantera och lagra dessa gjutformar på ej fungerar ur ett personsäkerhet- och effektivitetsperspektiv. ABB har fått två koncept på hur dessa problem kan lösas. Ett koncept som använder sig av ett kulgov. Det andra är ifrån ELE Engineering AB som föreslår att ett skensystem monteras i undersidan av entresolplanet vilket skapar plats för 60st nya gjutformar. Detta arbete syftar till att utreda hur entresolplanet påverkas av ELEs förslag, hur det ska förstärkas samt att utreda vilket av koncepten som är att föredra.

    Genom olika simuleringar föreslås att entresolplanet förstärks med 21st nya sekundärbalkar och 5st pelare för att klara den belastning som gjutformarna ger upphov till. Den harmoniserade standarden EN-1090 har legat till grund för hur dessa pelare och sekundärbalkar som föreslås ska utformas och infästas. Som lösning rekommenderas ELEs koncept baserat på en konceptjämförelse trots brist på tillräckligt information kring kulgolvet.

  • 21.
    Arguello, Nicolay
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Iñiguez, Enric
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Renewable Energy Emergency Microgrid Optimization in Ludvika2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the community of Ludvika, a Renewable Energy Emergency Microgrid (REEM) has been defined to provide back-up power during crisis situations. An Energy Storage System (ESS) was designed to support the main loads of the Microgrid in the first working hours. Additionally, the ESS will start-up the hydro power station, which will replace the power supply from the battery after the set-up period. However, the necessity of understanding the operation of the major components, such as the photovoltaic (PV) system and the ESS, of the REEM in normal conditions is imperative.

    This study analyses a variety of scenarios to evaluate how the renewable energy of an isolated system can be managed. Alternatives for increasing self-consumption of PV power and reduce feed-in power in the REEM are investigated. All the solutions consider the complete system design and an additional economic analysis for supporting the decision-making. The results show that selling the energy to the grid is the best economic solution, followed by the distribution of energy. However, the difference of 0.5 % in the total net present cost (TNPC) makes the distribution system, including the ESS, an option to be considered. In the upcoming years, changes on the amount of energy produced by the PV system or increasing the battery capacity usage in normal operation can become more feasible.

  • 22.
    Argårds, Andreas
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Kartläggning av ytjämnheten efter kallvalsning för olika kallvalsade kvalitéer samt trimvalsningens påverkan på ytjämnheten2010Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Syftet med detta arbete är att kartlägga ytjämnheten på stålbanden efter kallvalsning samt hur den erhålla ytjämnheten påverkas av trimvalsningen. Detta för att undersöka om det är möjligt att minska ner användandet av någon valsyta i Tandemverket vid SSAB Borlänge. Genom att mäta ytjämnheten på stålband av olika kallvalsade kvalitéer efter kallvalsning och trimvalsning, mäta ytråheten på texturerade valsar före och efter användning samt genomföra test med nya ytkombinationer har ett antal resultat genererats. Två test där Docol 200 band som skulle levereras med bandyta 23 valsades med en grövre yta i Tandem (valsyta 48 istället för 34) än vad som är brukligt och sedan trimvalsades med ordinarie valsyta visade att det är möjligt att klara kraven på Ra-värde för bandyta 23 även på band som kallvalsats med en grövre valsyta än i vanliga fall. Dock är det inte säkerställt att kraven för yta 23 alltid kan uppnås på band kallvalsade med grövre valsyta. Trimvalsning med valsyta 57 i den kontinuerliga glödgningslinjen har ingen betydande påverkan på ytjämnheten för Docol 600 & 800 DP, dock påverkar den ytan för Docol 200 eftersom att dessa band har mindre spridning i Ra-värde efter trimvalsning jämfört med innan. Trimvalsning med valsyta 57 höjer toppantalet på bandens yta. Band av en högre hållfasthetsklass får lägre Ra-värde jämfört mot mjukare stålsorter. Band med stor tjockleksreduktion i Tandem får lägre Ra-värde, detta gäller speciellt Docol 200 där trenden är tydligast. Ra-värdet på de texturerade valsarna i Tandem sjunker mycket i början när de används, test har visat att redan under kalibreringen kan Ra-värdet minska med 0,8 µm – 1,3 µm.

  • 23.
    Ashraf, Ali Junaid
    Högskolan Dalarna, Akademin Industri och samhälle, Elektroteknik.
    DC Motor Speed Control via Fuzzy / Pole Placement / PI Controller2010Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This report presents a new way of control engineering. Dc motor speed controlled by three controllers PID, pole placement and Fuzzy controller and discusses the advantages and disadvantages of each controller for different conditions under loaded and unloaded scenarios using software Matlab. The brushless series wound Dc motor is very popular in industrial application and control systems because of the high torque density, high efficiency and small size. First suitable equations are developed for DC motor. PID controller is developed and tuned in order to get faster step response. The simulation results of PID controller provide very good results and the controller is further tuned in order to decrease its overshoot error which is common in PID controllers. Further it is purposed that in industrial environment these controllers are better than others controllers as PID controllers are easy to tuned and cheap. Pole placement controller is the best example of control engineering. An addition of integrator reduced the noise disturbances in pole placement controller and this makes it a good choice for industrial applications. The fuzzy controller is introduce with a DC chopper to make the DC motor speed control smooth and almost no steady state error is observed. Another advantage is achieved in fuzzy controller that the simulations of three different controllers are compared and concluded from the results that Fuzzy controller outperforms to PID controller in terms of steady state error and smooth step response. While Pole placement controller have no comparison in terms of controls because designer can change the step response according to nature of control systems, so this controller provide wide range of control over a system. Poles location change the step response in a sense that if poles are near to origin then step response of motor is fast. Finally a GUI of these three controllers are developed which allow the user to select any controller and change its parameters according to the situation.

  • 24.
    Awda, Fadi
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Omkonstruktion av luftkylning för enfasreaktor2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Uppgiften för detta examensarbete var att undersöka överslag för tre reaktorenheter på grund av fukt och smuts som förts in i reaktorn genom kylsystemet. Syftet var att ta fram en lösning som ger reaktorn möjlighet att vara aktiv utan att påverkas av den mängd fukt och smuts som finns i omgivningen.

    Företaget hade inte resurser att ta fram en lösning på kort tid så både tid och kostnad en stor faktor i uppgiften. De krav som kunden har är att samtliga detaljer ska monteras på plats och att det inte påverkar hallarna där reaktorerna idag befinner sig. För att ta fram lösningar behövde reaktorns funktioner brytas ner i enklare delar, sedan valdes koncept som antingen påverkar miljön runtomkring eller konstruktionen av reaktorn.

    Den säkerhet kunden vill ha är att kylning ska vara minst lika effektiv i den nya lösningen och att vi åtgärdat det som orsakat haveriet, vilket var en blandning av smuts och fukt. Valen av lösningar blev; en lösning att lägga in övervakningsutrustning i reaktorn för temperaturövervakning, dessutom valdes en ny konstruktion för att dra om kylningens luftflöde och därmed undvika att fukt bildas inne i reaktorn och risk för överslag.

  • 25.
    Aylott, Benjamin
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Techno-Economic Evaluation of Distributed Generation within a Community Smart Grid with Demand Side Response Using HOMER2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In this study the distributed generation of renewable energy, primarily photovoltaic power, and consumption of energy within a geographically dispersed smart grid or ‘virtual micro grid’ is simulated using a model based around the HOMER Pro software with the aim of gaining insight into the economic and environmental performance of the system under different assumptions about the configurations of the generators and the presence of low carbon technologies such as heat pumps and electric vehicles. Demand side response for the purpose of reducing carbon emissions was also investigated as part of this.

    As well as simulating the system within HOMER, the study involved constructing a representative load profile for 200 domestic consumers and other loads using existing data, implementing a model for demand side response, using a range of detailed technical and environmental data to configure the HOMER model, and creating custom plotting tools. These features were connected in a data analysis pipeline written in Python included as part of the submission.

    The study found that to improve the environmental and economic performance of the system increasing the amount of renewable generation should be prioritized over other measures, such as demand side response. PV was the easiest to add due to lower upfront costs (compared to battery storage systems and mid-scale wind turbines) and lower financial and regulatory overheads. Carbon emissions were found to be minimized for around 3.5kW of PV per household in this scenario. Including a single mid-scale wind turbine was found to have the potential to greatly increase renewable penetration, and reduce carbon emissions and the cost of energy due to the complementary nature of PV and Wind power production. Battery storage at low penetrations was found to have little impact, but can make a large impact at high penetration but at significant financial expense.

    A range of battery products was also investigated for their suitability for use within the project and future schemes and were evaluated by locating them in the Renewable Fraction/LCOE plane.

    The inclusion of low carbon technologies such as heat pumps and electric vehicles was found to have some negative impact on the performance where only PV is present in the smart grid with little evidence that it can make better use of the renewable power due to poor matching with the available PV generation.

  • 26.
    Azizoğlu, Yağız
    Högskolan Dalarna, Akademin Industri och samhälle, Materialteknik. Luleå University of Technology.
    Modeling of Cold Pilgering of Tubes2017Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Cold pilgering is a challenging tube forming process in terms of modeling due to the complexity in kinematic of tools, friction condition and material behavior. The process development has mostly been based on simple formulas and costly full-scale tryouts. The aim in this study is to develop validated Finite element models of cold pilgering to increase the understanding of influence of the process parameters on the produced tubes.

    In the course of this thesis, three-dimensional mechanical and thermo-mechanical Finite element models of cold pilgering were developed. The commercial code MSC.Marc was used in the simulations. General 3D models are needed to be able to capture asymmetric deformation in cold pilgering. It was found that tool deflections together with elastic deformation of roll dies have considerable influence on the rolling force. Furthermore, the strain rate and temperature effects on the response of the material and thereby on the rolling force were evaluated.

  • 27.
    Azizoğlu, Yağız
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Materialteknik. Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Gärdsback, Mattias
    Sandvik Materials Technology, R&D, Sandviken..
    Sjöberg, Bengt
    Sandvik Materials Technology, R&D, Sandviken..
    Lindgren, Lars-Erik
    Luleå University of Technology.
    Finite element analysis of cold pilgering using elastic roll dies2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    A finite element model of cold pilgering with elastic roll dies have been developed and used to investigate the influence of roll die deformation on the material flow, contact region, roll separating force and tube dimensions. Full scale experiments were performed to validate the contact surface and tube dimensions. The results show that the influence of roll die flattening is not significant on the contact length. However, elastic deformation of roll die has strong influence on both the wall thickness reduction and roll separating force. Thus it is recommended to consider elasticity of roll dies when forces and tube dimensions are estimated.

  • 28.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    ClimateWell TDC with District Heat2010Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The PolySMART demonstration system SP1b has been modeled in TRNSYS and calibrated against monitored data. The system is an example of distributed cooling with centralized CHP, where the driving heat is delivered via the district heating network. The system pre-cools the cooling water for the head office of Borlänge municipality, for which the main cooling is supplied by a 200 kW compression chiller. The SP1b system thus provides pre-cooling. It consists of ClimateWell TDC with nominal capacity of 10 kW together with a dry cooler for recooling and heat exchangers in the cooling and driving circuits. The cooling system is only operated from 06:00 to 17:00 during working days, and the cooling season is generally from mid May to mid September. The nominal operating conditions of the main chiller are 12/15°C.

    The main aims of this simulation study were to: reduce the electricity consumption, and if possible to improve the thermal COP and capacity at the same time; and to study how the system would perform with different boundary conditions such as climate and load.

    The calibration of the system model was made in three stages: estimation of parameters based on manufacturer data and dimensions of the system; calibration of each circuit (pipes and heat exchangers) separately using steady state point; and finally calibration of the complete model in terms of thermal and electrical energy as well as running times, for a five day time series of data with one minute average data values. All the performance figures were with 3% of the measured values apart from the running time for the driving circuit that was 4% different. However, the performance figures for this base case system for the complete cooling season of mid-May to midSeptember were significantly better than those for the monitoring data. This was attributed to long periods when the monitored system was not in operation and due to a control parameter that hindered cold delivery at certain times. 

  • 29.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    European resarch school on large scale solar thermal - SHINE2014Ingår i: Solar District Heating 2014, Hamburg, Germany, 2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The Solar HeatIntegration NEtwork (SHINE) is a European research school in which 13 PhDstudents in solar thermal technologies are funded by the EU Marie-Curie program.It has five PhD course modules as well as workshops and seminars dedicated to PhDstudents both within the project as well as outside of it. The SHINE researchactivities focus on large solar heating systems and new applications: ondistrict heating, industrial processes and new storage systems. The scope ofthis paper is on systems for district heating for which there are five PhDstudents, three at universities and two at companies. The PhD students allstarted during the early part of 2014 and their initial work has concentratedon literature studies and on setting up models and data collection to be usedfor validation purposes. The PhD students will complete their studies in2017-18.

  • 30.
    Bales, Chris
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Andersen, M.
    Bava, F.
    Louvet, Y.
    Peréz de la Mora, N.
    Sotnikov, A.
    Shantia, A.
    SHINE Doctoral School: Results from six PhD studies on large scale solar thermal2016Ingår i: 4th International Solar District Heating Conference, 2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The Solar Heat Integration NEtwork (SHINE) is a European research school in which 13 PhD students in solar thermal technologies are funded by the EU Marie-Curie program. It has five PhD course modules as well as workshops and seminars dedicated to PhD students both within the project as well as outside of it. The SHINE research activities focus on large solar heating systems and new applications: on district heating, industrial processes and new storage systems. The scope of this paper is on systems for district heating for which there are six PhD students, five at universities and one at a company. The initial work concentrated on literature studies and on setting up initial models and measurement setups to be used for validation purposes. The measurements have been used for validating simulation models, including those used for extending the capabilities of the planning tool Polysun to simulate smaller district heating systems. Some results of these studies are presented in the paper. The PhD students will complete their studies in 2017-18.

  • 31.
    Bales, Chris
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Gustafsson, Marcus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Chiara, Dipasquale
    Roberto, Fedrizzi
    Alessandro, Bellini
    Matteo, D’Antoni
    Fabian, Ochs
    Georgios, Dermentzis
    Sarah, Birchall
    D2.1c Simulation Results of Reference Buildings2014Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report is the third part of the deliverable D2.1, where the other two parts report on the energy consumption in the building stock in Europe based on the available energy statistics (D2.1a) and the energy policies related to buildings (D2.1b).The aim of this report is to give complementary information about the heating and cooling demands of residential and office buildings based on simulations, so that the many gaps in the energy statistics can be filled and the statistics can be critically evaluated. The methodology results in a complete and consistent overview of the heating and cooling demands in residential and office buildings for seven different climate regions covering the whole of the EU and six different periods of construction, covering pre-1945 to post 2000. In addition, the data for the residential building stock is split into single family houses, small and large multifamily houses, while for offices the results are given for low and high rise offices with 6 or 12 office units per floor.The simulation models have been benchmarked (calibrated) against the energy statistics for each of the seven climate regions based on the aggregated data for the whole residential building stock and then for the office building stock in that climate region (in D2.1a). The methodology derives the aggregated average using weighted averages of data split into periods of construction and typology for both energy statistics and simulation results. The weighting is done based on heated and cooled floor area. As nearly all of the energy statistics are given in terms of consumption, while simulation results were calculated as demand, the demand data were converted to consumption data. One fixed conversion factor was used for heating (average efficiency 0.8) and one for cooling (average EER 2.5). Since the calculated demands strongly depend on the imposed heating or cooling set temperatures, this simulation parameter was varied so that the aggregated simulation result was the same as that for the consumption derived from the energy statistics. The calibrated models were then used to derive the average heating and cooling consumptions of the building stock in the seven climate regions.The methodology has a number of uncertainties, both in terms of the energy statistics as well as in terms of the simplifications and assumptions in the simulation models. During the calibration process a number of inconsistencies have been detected for individual countries and climate regions between simulation results and energy use from statistic data. The mismatches are analytically assessed, showing improvements necessary both in terms of statistic data necessary for reliable energy estimations and data to be gathered in order to guarantee consistent simulations outcomes.Beside the building stock survey completion and statistic data quality assessment, the work is also the basis for the definition of suitable Energy Renovation Packages and Products within the iNSPiRe project. The simulation results will be used to identify which building typologies, periods of construction and climate region have the largest potential for impact on the European scenario. Such information will be used within the iNSPiRe project to define reference Target buildings, as virtual demonstration cases to prove the potential improvements and impacts following the renovation process of a given share of the European building stock.

  • 32.
    Bales, Chris
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lorenz, Klaus
    Application of Polysun in Teaching Courses in Sweden and in the PhD Program SHINE2016Ingår i: SIGES Internationale Konferenz zur Simulation gebäudetechnischer Energiesysteme, 2016, s. 90-95Konferensbidrag (Övrigt vetenskapligt)
  • 33.
    Bales, Chris
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Nielsen, Christian
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Peréz de la Mora, Nicolás
    Sotnikov, Artem
    Louvet, Yoann
    Bava, Federico
    Shantia, Alireza
    Lennermo, Gunnar
    Seven Phd Studies on Solar District Heat2014Ingår i: EuroSun 2014 / ISES Conference Proceedings (2014), ISES , 2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The Solar Heat Integration NEtwork (SHINE) is a European research school in which 13 PhD students in solar thermal technologies are funded by the EU Marie-Curie program. It has five PhD course modules as well as workshops and seminars dedicated to PhD students both within the project as well as outside of it. The SHINE research activities focus on large solar heating systems and new applications: on district heating, industrial processes and new storage systems. The scope of this paper is on systems for district heating for which there are six PhD students, three at universities and two at companies. In addition there is a seventh PhD in a Swedish national research school focused on energy efficiency within district heating networks (Reesbe). The initial work has concentrated on literature studies and on setting up initial models and measurement setups to be used for validation purposes. Some results of these studies are presented in the paper. The PhD students will complete their studies in 2017-18.

  • 34.
    Bastholm, Caroline
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Fiedler, Frank
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Techno-economic study of the impact of blackouts on the viability of connecting an off-grid PV-diesel hybrid system in Tanzania to the national power grid2018Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 171, nr 1, s. 647-658Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    National electrification plans for many countries with a low level of electrification promote the implementation of centralized and decentralized electrification in parallel. This paper explores different ways of utilizing an established off-grid PV-diesel hybrid system when the national grid becomes available. This is a rather unique starting point within the otherwise well-explored area of rural electrification. With particular focus on the impact of blackouts in the national grid, we evaluate the economic viability of some alternatives: to continue to use the off-grid micro-grid, to connect the existing micro-grid with or without battery backup to the national grid, or to use the national grid only. Our simulation results in HOMER demonstrate that with a grid without blackouts, there are few benefits to maintain the existing system. Low grid-connection fees, low tariffs and low revenues from selling excess electricity to the grid contribute to this result despite the fact that the system does not carry any investment costs. With a grid with blackouts, it is beneficial to maintain the system. The extent of blackouts and the load on the system determine which system configuration is most feasible. The results make clear the importance of taking blackouts in the national grid into consideration when possible system configurations are being evaluated. This is rarely quantified in studies comparing different electrification alternatives, but deserves more attention.

  • 35.
    Blackman, Corey
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. Mälardalens högskola.
    Evaluation of a thermally driven heat pump for solar heating and cooling applications2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Exploiting solar energy technology for both heating and cooling purposes has the potential of meeting an appreciable portion of the energy demand in buildings throughout the year. By developing an integrated, multi-purpose solar energy system, that can operate all twelve months of the year, a high utilisation factor can be achieved which translates to more economical systems. However, there are still some techno-economic barriers to the general commercialisation and market penetration of such technologies. These are associated with high system and installation costs, significant system complexity, and lack of knowledge of system implementation and expected performance. A sorption heat pump module that can be integrated directly into a solar thermal collector has thus been developed in order to tackle the aforementioned market barriers. This has been designed for the development of cost-effective pre-engineered solar energy system kits that can provide both heating and cooling.

    This thesis summarises the characterisation studies of the operation of individual sorption modules, sorption module integrated solar collectors and a full solar heating and cooling system employing sorption module integrated collectors. Key performance indicators for the individual sorption modules showed cooling delivery for 6 hours at an average power of 40 W and a temperature lift of 21°C. Upon integration of the sorption modules into a solar collector, measured solar radiation energy to cooling energy conversion efficiencies (solar cooling COP) were between 0.10 and 0.25 with average cooling powers between 90 and 200 W/m2 collector aperture area. Further investigations of the sorption module integrated collectors implementation in a full solar heating and cooling system yielded electrical cooling COP ranging from 1.7 to 12.6 with an average of 10.6 for the test period.

    Additionally, simulations were performed to determine system energy and cost saving potential for various system sizes over a full year of operation for a 140 m2 single-family dwelling located in Madrid, Spain. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a solar heating and cooling installation employing 20m2 of sorption integrated collectors.

  • 36.
    Blackman, Corey
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Experimental Evaluation and Concept Demonstration of a Novel Modular Gas-Driven Sorption Heat Pump2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHPs) exhibit possibilities in the reduction of energy use and environmental impact of heating systems that utilise natural gas. By utilising renewable thermal energy from the environment, that is, air, ground or water sources, significant reduction of primary energy use can be achieved. However, high cost, low coefficient of performance (COP) and large volume per unit thermal power produced have limited the proliferation of GDSHPs. In this work, exploiting the benefits of reversible chemical reactions in sorption systems, with no internal moving parts, noise, vibration and maintenance-free reactor design, two novel modular prototype sorption components were developed and evaluated experimentally. They were designed to operate as part of an intermittent cycle GDSHP to deliver heat directly to a load or to a stratified hot water store. Prototype 1 was an ammonia-salt basic sorption unit while prototype 2 was an ammonia-salt resorption unit both employing proprietary composite sorbent materials. Test results showed that the prototype 2 reactor produced a specific heating capacity of 46 W/litre at a temperature lift of 50°C yielding a COP of 1.38. Prototype 1 demonstrated higher heating capacity of 73 W/litre at a temperature lift of 70°C but exhibited lower COP of 1.10. Given its higher COP but lower temperature lift, prototype 2 could be employed in a GDSHP designed for moderate heating demands or where a ground source heat exchanger is employed as the low temperature heat source. In the case where a higher temperature lift is required, for example, for an air-source GDSHP unit then the prototype 1 design would be more applicable.

  • 37.
    Blackman, Corey
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Study of Optimal Sizing for Residential Sorption Heat Pump System2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water (DHW) production in residential applications. In this study a bivalent system was considered, characterised by the integration of a novel modular sorption heat pump component and a condensing boiler. The modular heat pump component, or sorption module (SM), has been developed in two types: Type A and Type B, either of which could be integrated into a bivalent GDSHP system. The Type A sorption module had a functioning principle based on a solid chemisorption cycle, while Type B operates under a resorption cycle. To investigate the applicability of each SM type, a bivalent GDSHP system with a Type A SM (GDSHPA) and one with a Type B SM (GDSHPB) were evaluated. Simulations of year-round space heating loads for two single family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) for each GDSHP system calculated. The impact of the ratio of the design heating capacity of the SM compared to the peak heating capacity of the bivalent GDSHP was studied. Results show that SGCOP was not significantly affected for SM design heating capacity ratios greater than 66% of the peak GDSHPA design capacity in Minnesota, and 21% for GDSHPB. In New York, the ratios were 55% and 35% for GDSHPA and GDSHPB respectively.

  • 38.
    Blackman, Corey
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Test Platform and Methodology for Model Parameter Identification of Sorption Heat Pump Modules2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sorption heat pumps are employed in various heat-driven cooling and heat pumping applications. These heat pumps may be driven by solar energy, natural gas, biogas, geothermal energy or waste heat. Given that a plethora of heat sources and sorption materials can be exploited for different applications, various sorption heat pump modules have been developed. The sorption modules are pre-engineered sorption components for increased ease of sorption system development, improved cost effectiveness and reduced system complexity for various applications. However, in the design of sorption modules, component and system modelling and simulation are useful in the process of determining the optimal candidate of several possible sorption working couples for a given application. A test platform has been developed and a test methodology devised for the rapid characterisation of the transient behaviour of the sorption modules. The testing apparatus was used to derive various model parameters to be used for validation of a dynamic sorption module component model. The test method was analogous to that employed for dynamic testing and performance modelling of electrochemical accumulators (i.e. electric batteries) given the similarities between them and sorption modules (also known as thermochemical accumulators). The model parameter identification was based on various heating and cooling power performance parameters as a function of state of charge (SoC) of the sorption modules. A 7-step procedure was used to characterise the performance of the sorption modules based on experimental data. A reference performance for charge and discharge of the sorption modules was measured followed by several measurements at ‘off-reference’ conditions. Performance curves for ‘off-reference’ conditions were then correlated to reference conditions to generate performance curves that describe the transient cooling and heating power delivery of the sorption module at any point within the test range. Results showed that the discharge performance of the sorption modules could be predicted within a reasonable margin of error with a test run sequence of 39 cycles.

  • 39.
    Blackman, Corey
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. Mälardalen University.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Experimental evaluation of a novel absorption heat pump module for solar cooling applications2015Ingår i: Science and Technology for the Built Environment, ISSN 2374-4731, Vol. 21, nr 3, s. 323-331Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Given the environmental benefits of utilizing free thermal energy sources, such as waste heat and solar energy for cooling purposes, many developments have come about in thermally driven cooling. However, there are still some barriers to the general commercialization and market penetration of such technologies that are associated with system and installation costs, complexity, and maintenance. In efforts to overcome these limitations, a novel absorption heat pump module has been developed and tested. The module comprises a fully encapsulated sorption tube containing hygroscopic salt sorbent and water as a refrigerant, sealed under vacuum, and within which there are no moving parts. The absorption module consists of two main components, one that alternately functions as an absorber or generator and other that alternates between the roles of evaporator and condenser. The module therefore operates cyclically between a cooling delivery phase and a regeneration phase. Each module has a significant energy storage capacity with cooling delivery phases ranging from 6-10 h in length with temperature lifts between 16 degrees C and 25 degrees C. The modules are optimized for integration directly into a solar thermal collector, for roof or facade installation, for daytime regeneration and night-time cooling delivery. Collector integrated modules would be completely modular maintenance-free absorption heat pumps with similar installation requirements to standard solar thermal collectors. This article describes the test method and performance characteristics of the individual absorption modules.

  • 40.
    Blackman, Corey
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. Mälardalen University.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Hallström, Olof
    Mälardalen University.
    Demonstration of Solar Heating and Cooling System using Sorption Integrated Solar Thermal Collectors2014Ingår i: EuroSun 2014 / ISES Conference Proceedings (2014), ISES , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Producing cost-competitive small and medium-sized solar cooling systems is currently a significant challenge. Due to system complexity, extensive engineering, design and equipment costs; the installation costs of solar thermal cooling systems are prohibitively high. In efforts to overcome these limitations, a novel sorption heat pump module has been developed and directly integrated into a solar thermal collector. The module comprises a fully encapsulated sorption tube containing hygroscopic salt sorbent and water as a refrigerant, sealed under vacuum with no moving parts. A 5.6m2 aperture area outdoor laboratory-scale system of sorption module integrated solar collectors was installed in Stockholm, Sweden and evaluated under constant re-cooling and chilled fluid return temperatures in order to assess collector performance. Measured average solar cooling COP was 0.19 with average cooling powers between 120 and 200 Wm-2 collector aperture area. It was observed that average collector cooling power is constant at daily insolation levels above 3.6 kWhm-2 with the cooling energy produced being proportional to solar insolation. For full evaluation of an integrated sorption collector solar heating and cooling system, under the umbrella of a European Union project for technological innovation, a 180 m2 large-scale demonstration system has been installed in Karlstad, Sweden. Results from the installation commissioned in summer 2014 with non-optimised control strategies showed average electrical COP of 10.6 and average cooling powers between 140 and 250 Wm-2 collector aperture area. Optimisation of control strategies, heat transfer fluid flows through the collectors and electrical COP will be carried out in autumn 2014.

  • 41.
    Blackman, Corey
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Thorin, Eva
    Techno-economic evaluation of solar-assisted heating and cooling systems with sorption module integrated solar collectors2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 70, s. 409-417Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Currently the use of solar energy for heating and cooling isn't widespread. In order to reduce primary energy consumption in the built environment along with improving the thermal performance of the current building stock, retrofit solutions are required to utilise renewable energy. Using solar energy to reduce primary energy consumption is seen as a possible solution. With the precipitous fall in the prices of crystalline solar photovoltaic modules, utilising this technology to reduce electrical energy consumption for cooling is an attractive solution. Recently, a sorption module integrated collector has been developed in order to improve cost-effectiveness and simplify solar thermal heating and cooling systems. A techno-economic analysis has been performed to evaluate solar photovoltaic cooling and solar thermal cooling systems for residential renewable energy retrofit. The analysis is based on potential energy and cost savings according to simulated heating and cooling loads under climatic conditions of Madrid, Spain. Simplified models were used to determine heating and cooling demands and the solar energy contribution to heating and cooling loads. Additionally, given the sorption collector's unique capacity to store solar energy thermally and provide cooling at night an analysis has been carried out to identify the combined benefit of solar-assisted heating and cooling via photovoltaics during the day and solar sorption at night. For system sizes between 5m(2) and 20m(2) solar fractions between 16% and 64% could be achieved which translated to annual energy cost savings between (sic)153 to (sic)615. (C) 2015 The Authors. Published by Elsevier Ltd.

  • 42.
    Blackman, Corey
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. SaltX Technology, Hägersten, Stockholm; Mälardalen University.
    Gluesenkamp, Kyle R.
    Malhotra, Mini
    Yang, Zhiyao
    Study of optimal sizing for residential sorption heat pump system2019Ingår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 150, nr 5, s. 421-432Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water production in residential applications. This study considered a bivalent heating system consisting of a sorption heat pump and a condensing boiler, and focuses on the optimal heating capacity of each of these components relative to each other. Two bivalent systems were considered: one based on a solid chemisorption cycle (GDSHPA), and one based on a resorption cycle (GDSHPB). Simulations of year-round space heating loads for two single family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) calculated. The sorption heat pump’s design heating capacity as a fraction of the bivalent system’s total heating capacity was varied from 0 to 100%. Results show that SGCOP was effectively constant for sorption heat pump design capacity greater than 41% of the peak bivalent GDSHPA design capacity in Minnesota, and 32% for GDSHPB. In New York, these values were 42% and 34% for GDSHPA and GDSHPB respectively. Payback period was also evaluated based on postulated sorption heat pump component costs. The fastest payback was achieved with sorption heat pump design capacity between 22–44%.

  • 43.
    Brandsma, Age
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Performance Evaluation for a Solar Assisted Air Conditioning System in Taipei2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This report shows the study performed at Taipei National University of Technology in Taipei to evaluate the performance of a solar air conditioning system. The performance is evaluated under Taiwan climate conditions. The research is performed under summer weather conditions. No influence is done on these conditions. A solar air conditioning system currently available on the market is used. No changes are made to the system.

    The work to be done is divided into different phases in order to guide the process. First, a literature research is done to find similar research done on this topic and to gain a basic understanding of the topic. Then several measurement plans are made to investigate different parts of the system.. Measurements are done. It is tried to developing a computer model in order to be able to simulate the system performance.

    The overall objective was to gain knowledge about a solar assisted air-conditioning system and develop a model to simulate the system. Initially a list of research questions was made in order to quantify ‘gaining knowledge’ about the system. The plan was to answer them by using measurement data and creating a model to perform simulations. There are measurements done in this report, however due to too many ‘unknowns’* it is difficult to draw conclusions from them. A lot of research questions are still open and they are also not included in this report. It is also not succeeded to make a working model of a solar assisted air conditioner.

    It is succeeded in making a model to predict the performance of the evaporator. This model is currently within 11% accurate.

  • 44.
    Cano Garcia, Jose
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Damp Heat Degradation of CIGS Solar Modules2017Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Due to the short period that some photovoltaic technologies have taken part on the solar energy market, it is crucial to evaluate the long term stability of solar cells belonging to those technologies in order to ensure a minimum lifetime of their performance. Accelerated degradation tests are thus carried out to achieve such goals.

    The present study analyzes the encapsulation effects on co-evaporated manufactured Copper Indium Gallium Selenide (CIGS) solar cells under damp heat conditions, consisting in 85 °C and 85 % relative humidity, during an approximated period of 1000 hours. The experimental procedure has been carried out at Solliance Solar Research facilities.

    Since the encapsulation packages play a critical role as a protection to achieve long term stability of the solar cells and modules, several packaging structures and materials has been taken into study. Thus, eighteen types of mini modules were manufactured including different combinations of encapsulants, front sheet foils, thin film protective barriers and CIGS cells from different manufacturers. The design of these mini modules and the manufacturing process to obtain them is also presented in this work. Various characterization techniques were carried out in order to acquire the required information about the solar cells and encapsulants performance along the damp heat degradation process.

    The results exposed that encapsulation packages including thin film barriers between the encapsulant and the front sheet foil allowed a longer solar cell lifetime due to their remarkable protection against moisture ingress. Moreover, the degradation of the molybdenum layer included in the CIGS cells was found as principal cause of efficiency decrement and end of performance of solar cells protected by regular encapsulant and front sheet foils. Some other findings in relation with the evaluated components are shown along the present study.

  • 45. Cantos-Soto, María Elena
    et al.
    Fernández-García, Aránzazu
    Matteudi, Maud
    Rönnelid, Mats
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Martínez-Arcos, Lucía
    Solar Reflectors Degradation Caused by Simulated Solar Radiation2012Ingår i: Solar PACES 2012, 2012Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The feasibility of concentrating solar power (CSP) technologies strongly depends on the material used toachieve a suitable solar reflector. A very relevant issue nowadays is to find a cost-effective reflector materialwith appropriate optical properties, able to resist the environmental stress and, therefore, extending itslifetime. This research work is focused on evaluating the thick silvered-glass reflector’s degradation causedby solar radiation onto different solar reflector samples, exposed to both experimental settings, simulatedsunlight under accelerated conditions and solar radiation at real outdoor conditions. The experiments havebeen performed in the optical characterization and durability of solar reflectors laboratory at the PlataformaSolar de Almeria (PSA). Three different chambers were used to reproduce the entire or specifics ranges ofthe solar radiation spectrum. Samples from 6 different manufacturers were placed inside of every sunlightchamber during 2000 hours. The outdoor exposure in the PSA precincts lasted for 4000 hours.

  • 46. Cao, x
    et al.
    Yuan, Y
    Xiang, B
    Sun, L
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Numerical investigation on optimal number of longitudinal fins in horizontal annular phase change unit at different wall temperatures2018Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 158, s. 384-392Artikel i tidskrift (Refereegranskat)
  • 47.
    Ceron, Ermanno
    et al.
    Technical University of Denmark.
    Olsson, Mikael
    Högskolan Dalarna, Akademin Industri och samhälle, Materialteknik.
    Bay, Niels
    Technical University of Denmark.
    Lubricant film breakdown and material pick-up in sheet forming of advanced high strength steels and stainless steels when using environmental friendly lubricants2014Ingår i: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 966-967, s. 219-227Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increasing focus on environmental issues in industrial production has urged sheet metal stamping companies to look for new tribo-systems in order to substitute hazardous lubricants such as chlorinated paraffin oils. The efficiency of chlorinated paraffin is due to the fact that the lubricant reacts chemically with the tool and workpiece material forming thin films, which adhere strongly to the surfaces and reduce the tendency to metal-metal contact and material pick-up. Production tests of new, environmentally benign tribo-systems are, however, costly and laboratory tests are preferred as a preliminary simulative method to investigate alternative tribo-systems. The present paper presents a case study where an industrial process, consisting of deep drawing with two subsequent re-drawings, was selected and four potential new tribo-systems were tested including different workpiece materials, i.e. AHSSs and stainless steels. The performance of the tribo-systems was analyzed in the laboratory by means of a newly developed simulative test as well as in an industrial production process. The results obtained show a good agreement between the laboratory test and the industrial production process regarding the tribological performance, i.e. tendency to material pick-up and galling, of the evaluated tribo-systems. Moreover the SEM analysis shows that different workpiece materials result in different types of material pick-up.

  • 48. Chen, X
    et al.
    Su, Y
    Aydin, D
    Bai, H
    Jarimi, H
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Raffat, S
    Experimental investigation of a polymer hollow fibre integrated liquid desiccant dehumidification system with aqueous potassium formate solution2018Ingår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 142Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hollow fibres have been studied as the substitute for metallic materials due to the advantages such as light weight, corrosion resistant and low cost in heat and mass transfer applications. A novel polymer hollow fibre liquid desiccant dehumidification system, in which a cross-flow hollow fibre module (fibre inside diameter=1.4mm) serves as the dehumidifier, is presented in this paper. This novel hollow fibre integrated liquid desiccant dehumidification system can be used in an air conditioning system to provide a comfortable indoor environment for hot and humid area. Compared with other conventional liquid desiccant dehumidifier, the polymer hollow fibre has a very small diameter which leads to significantly increased surface area. Moreover, the porous feature of the hollow fibre module can help to eliminate any liquid desiccant droplets carryover into the process air. As a less corrosive and more environmental friendly working fluid, aqueous potassium formate (KCOOH) solution has been selected. The dehumidification performance of the proposed system were analysed experimentally under the conditions of incoming air temperature in the range of 30°C to 45°C. The variations of dehumidification sensible and latent effectiveness, moisture removal rates were studied by varying the incoming air velocity from 0.65 m/s to 4.5m/s. With the various values of incoming air relative humidity in the range of 55% to 75% and the solution concentrations between 36% and 62%, the experimental obtained latent effectiveness are in the range of 0.25 to 0.43 and the sensible effectiveness are in the range of 0.31 to 0.52, which is in a satisfactory agreement with the empirical correlation of effectiveness-NTU in the literature.

  • 49. Chen, X.
    et al.
    Su, Y.
    Aydin, D.
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Ding, Y.
    Reay, D.
    Law, R.
    Riffat, S.
    Experimental investigations of polymer hollow fibre integrated evaporative cooling system with the fibre bundles in a spindle shape2017Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 154, s. 166-174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Due to the advantages of light weight, corrosion resistant and low cost, hollow fibres have been studied as the substitute for metallic materials. A novel hollow fibre integrated evaporative cooling system, in which the hollow fibre module constitutes as the humidifier and the evaporative cooler, is proposed. This novel hollow fibre integrated evaporative cooling system will provide a comfortable indoor environment for hot and dry area. Moreover, the water vapour can permeate through the hollow fibre effectively, and the liquid water droplets will be prevented from mixing with the processed air. In order to avoid the flow channelling or shielding of adjacent fibres, the fibres inside each bundle were made into a spindle shape to allow maximum contact between the air stream and the fibre. The cooling performances of the proposed novel polymer hollow fibre integrated evaporative cooling system were experimentally investigated under the incoming air temperature in the range of 26 °C to 32 °C and relative humidity of 25%–35%. The effects of air velocities on the cooling effectiveness, heat and mass transfer coefficients, specific water consumption and pressure drop across the polymer hollow fibre module were analysed. Two sets of experimentally derived non-dimensional heat and mass transfer correlations were summarized, which could be favourable for the future design of polymer hollow fibre integrated evaporative cooling system.

  • 50.
    Cubillas Camou, Elsa
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Performance Analysis on Photovoltaic Plant in Norway2018Självständigt arbete på avancerad nivå (masterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The purpose of this study is to analyze the performance of the biggest PV system located in Oslo, Norway. The PV system has a capacity of 130 kW, it started operations in 2014 and it is located on the rooftop of a nursing house managed by the municipality. The analysis was done by making four different comparisons that lead to have a more detailed overview. The comparisons were from the energy production from different years, months and days; the performance ratio from different subsystems; the modeled energy output vs the actual energy output and lastly a relative degradation from different subsystems.

    The thesis was conducted in Kjeller, Norway at the Institute for Energy Technology facilities. Data was collected from two different monitoring systems, the first was from an onsite weather station and the second was from the energy production monitoring system. After collecting all the data, the production comparison from different years, days and months was performed. A performance ratio analysis was done in order to know how well the PV system was performing. The software HelioScope was used to simulate a model of the PV system and the results of the simulation were compared to the real energy output. A degradation analysis without irradiance data proposed by the National Renewable Energy Laboratory was implemented to compare the degradation rate between different subsystems.

    The production analysis comparison within subsystems demonstrates that some identical subsystems produce more energy than others. For the performance ratio analysis, the results showed that the PV system has a good performance ratio despite of the shading some PV modules receive. The simulation of the model in HelioScope showed some discrepancies for the winter months while for summer months it was more accurate. Finally, the degradation analysis was not possible to demonstrate actual results, but the methodology was implemented.

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