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  • 301.
    Swarén, Mikael
    et al.
    Mittuniversitetet, Institutionen för hälsovetenskap.
    Danvind, Jonas
    Holmberg, Hans-Christer
    Mittuniversitetet, Institutionen för hälsovetenskap.
    Acceleration of the head during alpine skiing2012In: Science and skiing V / [ed] Erich Müller, Stefan Lindinger, Thomas Stöggl, Meyer & Meyer Sport , 2012, p. 443-451Chapter in book (Refereed)
  • 302.
    Swarén, Mikael
    et al.
    KTH, Strukturmekanik.
    Eriksson, Anders
    KTH, Strukturmekanik.
    Holmberg, H.-C.
    Swedish Winter Sports Research Center, MiUn.
    Treadmill simulation of olympic cross country ski track2012In: Proceedings of 2nd International Congress on Science and Nordic Skiing 2012, Vuokatti: ICSNS 2012 , 2012Conference paper (Refereed)
  • 303.
    Swarén, Mikael
    et al.
    Mittuniversitetet, Avdelningen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Avdelningen för hälsovetenskap.
    Eriksson, Anders
    Department of Mechanics, Royal Institute of Technology, Stockholm, Sweden.
    Repeated low impacts in alpine ski helmets2013In: Sports Technology, ISSN 1934-6182, E-ISSN 1934-6190, Vol. 6, no 1, p. 43-52Article in journal (Refereed)
    Abstract [en]

    Alpine ski race helmets are subjected to multiple impacts during a race caused by the skiers hitting the gates on their way down the course. This study investigated the difference between expanded polystyrene (EPS) and expanded polypropylene (EPP) cores in alpine ski race helmets when subjected to repetitive violence, caused by alpine slalom gates. A special test rig was developed where a rotating slalom pole impacted the helmets with a velocity of 13.3 m·s− 1. All helmets (six EPS and six EPP) were attached to a headform, monitored with a triaxial accelerometer at the center of mass. Each helmet sustained 1000 impacts and acceleration data were collected around every 200 impacts. No significant differences were observed between the first hit and after 1000 hits for either the EPS or the EPP helmets. However, the total group mean acceleration and mean peak acceleration were 15% and 16% higher, respectively, for the EPS series compared with the EPP series. Also, all EPS helmets showed cracked cores after 1000 impacts compared with 1 cracked EPP core. Findings suggest that EPP cores might be more suitable for absorbing multiple low impacts caused by alpine gates and that repeated violence is a relevant parameter to consider when constructing alpine ski race helmets.

  • 304.
    Swarén, Mikael
    et al.
    KTH, Strukturmekanik.
    Karlöf, L.
    Holmberg, Hans-Christer
    Eriksson, Anders
    KTH, Strukturmekanik.
    Validation of test setup to evaluate glide performance in skis2014In: Sports Technology, ISSN 1934-6182, E-ISSN 1934-6190, Vol. 7, no 1-2, p. 89-97Article in journal (Refereed)
    Abstract [en]

    Although today's ski waxing chemicals and micro-machining techniques of the ski base are highly sophisticated, objective procedures for testing and verification of the results have not yet been developed and evaluation is based on comparison of subjective experience. The purpose of the present study was thus to compare different setups for testing the glide of cross-country skis. Two differently waxed ski pairs were tested for glide inside a ski tunnel. Inertial measurement units (IMUs) were attached to each ski; instantaneous velocities monitored by three different speed-traps; the velocities during the acceleration phase determined by Doppler radar. Kinetic, potential and total energy, giving the energy dissipation, were calculated for four representative trials during the acceleration phase. No reliable data were obtained from the IMUs due to high drift. The mean maximal velocity for the two ski pairs were 6.97, s = 0.09 and 6.70, s = 0.09 m·s − 1, respectively. Higher differences between the skis were identified during the retardation phase compared to the acceleration phase. The mean difference between the velocities determined by the speed-trap and Doppler radar was 0.6, s = 1%, demonstrating that the latter provides accurate data for evaluation of gliding characteristics and performance. However, theoretical confirmation of the friction coefficient, on the basis of data provided by Doppler radar and energy calculations requires exact measurements of the inclination and topography of the track in question.

  • 305.
    Swarén, Mikael
    et al.
    KTH, Strukturmekanik.
    Therell, Mikael
    Swedish Winter Sports Research Center, MiUn.
    Eriksson, Anders
    KTH, Strukturmekanik.
    Holmberg, H.-C.
    Swedish Winter Sports Research Center, MiUn.
    Cross-country ski poles: Introduction of a shaft strength index2012In: Proceedings of the 2nd International Congress on Science and Nordic Skiing 2012, ICSNS , 2012Conference paper (Refereed)
  • 306.
    Swing Gustafsson, Moa
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalen University.
    The impact on the energy system of heating demands in buildings: A case study on district heating and electricity for heating in Falun, Sweden2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Energy efficiency measures in buildings are considered to have great potential in order to reduce total energy consumption, and thus contribute to a reduced environmental impact and a better climate. In Sweden, however, the energy performance requirements for buildings are formulated in terms of bought energy, i.e. as bought electricity and district heating (DH), which does not always reflect the environmental and climate impact from a broader perspective. Focusing on bought energy means that many choose an electricity-based heat pump solution in their building instead of DH, since heat pumps result in a smaller amount of bought energy compared to DH.

    The surrounding energy system of the buildings is affected by the choice of energy carriers used for heating. How the energy system is affected is studied in this thesis using two different methods. In the first part, primary energy consumption has been calculated for a simulated building with different heating solutions, representing different electricity and DH demands. In the second part, the impact on total consumption in the surrounding power and DH networks due to different market shares of electricity-based heating and DH has been studied. The second part also includes an analysis of the potential to produce electricity using combined heat and power (CHP) in different scenarios depending on the market share of DH. This part has been carried out as a case study for the Swedish municipality of Falun.

    The results show that the choice of energy carrier has a great influence on primary energy consumption. The resulting primary energy consumption does, however, to an even greater extent depend on the calculation method used. Which heating solution, and thus also which energy carrier, gets the lowest primary energy consumption varies in the different methods.

    The surrounding power and DH networks are also affected to a great extent by the choice of energy carrier. There is a huge potential to lower peak demand in the power grid by avoiding electricity-based heating. The potential to produce electricity using CHP is also increased with a larger market share for DH. In Falun, reduced electricity demand and increased electricity production using CHP make it possible to cover the peak power demand using only electricity production from CHP. In comparison, 10 % of the peak power demand was covered by electricity from CHP in 2015.

    The choice of energy carrier for heating in buildings affects the surrounding energy system to a high degree, and is therefore an important aspect to take into account in both local, national and global energy efficiency projects. 

  • 307.
    Swing Gustafsson, Moa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalen University.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Dotzauer, Erik
    Mälardalen University.
    Primary energy use in buildings in a Swedish perspective2016In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 130, p. 202-209Article in journal (Refereed)
    Abstract [en]

    The building sector accounts for a large part of the energy use in Europe and is a sector where the energy efficiency needs to improve in order to reach the EU energy and climate goals. The energy efficiency goal is set in terms of primary energy even though there are different opinions on how to calculate primary energy. When determining the primary energy use in a building several assumptions are made regarding allocation and the value of different energy sources. In order to analyze the difference in primary energy when different methods are used, this study use 16 combinations of different assumptions to calculate the primary energy use for three simulated heating and ventilations systems in a building. The system with the lowest primary energy use differs depending on the method used. Comparing a system with district heating and mechanical exhaust ventilation with a system with district heating, mechanical exhaust ventilation and exhaust air heat pump, the former has a 40% higher primary energy use in one scenario while the other has a 320% higher in another scenario. This illustrates the difficulty in determining which system makes the largest contribution to fulfilling the EU energy and climate goals.

  • 308.
    Swing Gustafsson, Moa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalen University.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Dotzauer, Erik
    Mälardalen University.
    Assessment of the potential for district heating to lower the peak electricity consumption in a medium size municipality in SwedenManuscript (preprint) (Other academic)
    Abstract [en]

    Sweden faces several challenges when more intermittent renewable power is integrated into the energy system. One of the challenges is to have enough electrical power available in periods with low production from intermittent sources. A solution to the problem could be to reduce the electricity peak demand and at the same time produce more electricity during peak hours. One way of doing this is to convert electricity based heating in buildings to district heating (DH) based on combined heat and power (CHP).

    The study analyzes how much a medium sized Swedish municipality can contribute to lower the electricity peak demand. This is done by quantifying the potential to reduce the peak demand for six different scenarios of the future heat market volume and heat market shares regarding electricity based heating and DH in 2050.

    The main finding is that electricity consumption will be reduced by 35-70 % during the peak hour (and 20-40 % on a yearly basis) for all the six scenarios studied compared with the current situation. If the aim is to lower the electricity peak demand in the future, the choice of heating system is more important than reducing the heat demand itself. For the scenario with a large share of DH, it is possible to cover the electricity peak demand in the municipality by using CHP.

  • 309.
    Swing Gustafsson, Moa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Life cycle cost of heat supply to areas with detached houses: a comparison of district heating and heat pumps from an energy system perspective2018In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 11, no 12, article id 3266Article in journal (Refereed)
    Abstract [en]

    There are different views on whether district heating (DH) or heat pumps (HPs) is or are the best heating solution in order to reach a 100% renewable energy system. This article investigates the economic perspective, by calculating and comparing the energy system life cycle cost (LCC) for the two solutions in areas with detached houses. The LCC is calculated using Monte Carlo simulation, where all input data is varied according to predefined probability distributions. In addition to the parameter variations, 16 different scenarios are evaluated regarding the main fuel for the DH, the percentage of combined heat and power (CHP), the DH temperature level, and the type of electrical backup power. Although HP is the case with the lowest LCC for most of the scenarios, there are alternatives for each scenario in which either HP or DH has the lowest LCC. In alternative scenarios with additional electricity transmission costs, and a marginal cost perspective regarding the CHP investment, DH has the lowest LCC overall, taking into account all scenarios. The study concludes that the decision based on energy system economy on whether DH should expand into areas with detached houses must take local conditions into consideration.

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  • 310.
    Swing Gustafsson, Moa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalen University.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Dotzauer, Erik
    Mälardalen University.
    Mapping of heat and electricity consumption in a medium size municipality in Sweden2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, p. 1434-1439Article in journal (Refereed)
    Abstract [en]

    The Nordic electricity system faces many challenges with an increased share of intermittent power from renewable sources. One such challenge is to have enough capacity installed to cover the peak demands. In Sweden these peaks appear during the winter since a lot of electricity is used for heating. In this paper a mapping of the heat and electricity consumption in a medium size municipality in Sweden is presented. The paper analyze the potential for a larger market share of district heating (DH) and how it can affect the electrical power balance in the case study. The current heat market (HM) and electricity consumption is presented and divided into different user categories. Heating in detached houses not connected to DH covers 25 % of the HM, and 30 % of the electricity consumption during the peak hours. Converting the detached houses not connected to DH in densely populated areas to DH could reduce the annual electricity consumption by 10 %, and the electricity consumption during the peak hours by 20 %.

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  • 311.
    Swing Gustafsson, Moa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Dotzauer, Erik
    Potential for district heating to lower peak electricity demand in a medium-size municipality in Sweden2018In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 186, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Sweden faces several challenges with more intermittent power in the energy system. One challenge is to have enough power available in periods with low intermittent production. A solution could be to reduce peak demand and at the same time produce more electricity during these hours. One way of doing this is to convert electricity-based heating in buildings to district heating based on combined heat and power. The study analyzes how much a Swedish municipality can contribute to lowering peak electricity demand. This is done by quantifying the potential to reduce the peak demand for six different scenarios of the future heat demand and heat market shares regarding two different energy carriers: electricity-based heating and district heating. The main finding is that there is a huge potential to decrease peak power demand by the choice of energy carrier for the buildings’ heating system. In order to lower electricity peak demand in the future, the choice of heating system is more important than reducing the heat demand itself. For the scenario with a large share of district heating, it is possible to cover the electricity peak demand in the municipality by using combined heat and power.

  • 312.
    Swing Gustafsson, Moa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Primary energy reduction in buildings: Case study on a residential building in Falun, Sweden2014In: Proceedings from the 14th International Symposium on District Heating and Cooling / [ed] Anna LAND, Swedish District Heating Association, 2014, p. 543-545Conference paper (Refereed)
    Abstract [en]

    Since a large share of the total European primary energy is consumed in the building sector, buildings have to become more energy efficient in order to reach the goals of the European energy efficiency directive. In Sweden, focus has been on lowering final energy consumption, not primary energy consumption. A relevant question today is whether a general understanding of the primary energy concept is needed to encourage selection of better energy efficiency measures from an environmental perspective. There are however uncertainties of how to calculate primary energy consumption since different primary energy factors (PEF) are used by different actors, especially for district heating (DH) and electricity (EL.).

    In this study total primary energy consumption was calculated for a residential building before and after several renovation measures were made. The major change after the renovation was that a large share of the DH was substituted by heat from an exhaust air heat pump and solar collectors. A range of commonly used PEFs were assessed.

    The evaluation showed that the energy efficiency measures reduced the total primary energy consumption for most combinations of PEFs. The most essential was how the DH was valued. A low PEF for DH in combination with most of the PEFs for electricity could even result in higher total primary energy consumption after the renovation.  

  • 313.
    Söderling, Linnea
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Minimering av resursanvändning för ett CIP-system: Undersökning med faktorförsök2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this degree project is to explore the possibility of reducing the use

    of resources in performing a so-called clean-in-place cleaning. The work answers

    questions about the possibilities that are available to streamline the process or to

    reduce media consumption by shortening rinse times in the cleaning process. The

    main method on which the work is based is factor attempts through trial planning.

    This is a method of structuring trials with several correlating factors. The factors

    that have been altered, with the goal of making resources use more efficient, are a

    reduction of the caustic temperature for cleaning, using different amounts of

    additives in the caustic solution and a shortened time for the last cold water rinse

    in the cleaning process. The analysis shows that approved results for cleaning are

    also obtained after changes have been made. A large part of the work has been

    focused on understanding the system's structure and function. Recycling waste

    water to a greater extent and using a lower caustic concentration could possibly

    allow to further reduce resource consumption.

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  • 314.
    Sömsk, Tony
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Investigate and develop a conceptual solution to eliminate excessive coupler parts wear-out: Mechanical Engineering Design and product development2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Dellner Couplers (now known as Dellner Train Connection System) is a manufacturer of couplers for passenger trains with their headquarters located in Vika, between Falun and Borlänge in Dalarna. For this thesis project Dellner had a wear problem of parts in the support and centering (SCD) device. This device is placed under the coupler, mounted to the pivot anchor in the rear and to the buffer tube in the center section, to support and center the coupler so that a coupling can be made without any manual work. When coupling has been made the SCD does not fill any function and wear issues occur due to hilltops and curves along the railroad which causes the coupler to move both vertically and horizontally. These movements cause the dampers to move in a linear fashion through the support damper holes in the front bracket and this leads to worn-out bushings/sleeves placed at the dampers. The problem is that the sleeves are worn-out after approximately four years while the normal maintenance interval is eight years.

    The project has investigated the wear problem to find the root cause and tried to investigate possible solutions in order to develop suitable concepts to solve the wear-out problem. The project is based on the product development process as given by Ulrich & Eppinger (2012) and the purpose and goal have been to apply this method to develop one or more concepts.

    After the analysis several ideas for different kinds of solutions were generated and some of these were picked for concept screening. For the concept screening eight possible concepts were included and presented as they possibly could act as the beginning of a new product or solution to solve the current problem with worn-out sleeves. Four concept ideas for an older type of bracket with an old interface, and four concept ideas for a newer bracket type with a new interface were presented.

    The conclusions are that the angular displacements between the axis of the damper (the strut) and the support damper holes are one root cause for the current problem as well as the movement of the dampers in the support damper holes. It is clear that this problem with worn-out sleeves is solvable within reasonable limits regarding time, complexity and economy. With more time, concept scoring followed by a final selection, final specifications and a detailed design would have been done and so are suggested as further work.

  • 315.
    Sörbom, Tobias
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Framtagning av automatiskt uraskningssystem2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Pellet boilers requires maintenance which includes removal of ash in the boiler, which customers have neither the time nor the will to perform manually. Therefore, the objective of this report has been to develop one or two concept proposals for an automatic ash removal system.The result consisted of two concepts to keep working with, both of which contains a screw con-veyor. Both solutions works in such a way that the screw transporter carries the ashes from the upper part of the boiler down to the ash box. The screws are driven by a motor with the help of shell wheels and shell screws.Why these two concepts became finalists was due to the fact that they both meet the tempera-ture requirement that the chimney has, removal of ash at least once a week, no change of the boiler design, manufacture on site and able to sell spare parts. However, these solutions are very expensive since the prices that were collected are for end users. There are opportunities to reduce costs so the requirement of the production costs is not exceeded, which is 1500 SEK.These conditions and requirements that were used as the basis for the selection of the concepthave been obtained through literature studies on, for example, pellets, ash, turbulator and chimney, as well as customer surveys and also internet search of existing automatic ash removal systems.

  • 316.
    Sörman, Erik
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Utveckling av en säker modell för statistisk processtyrning inom kabeltillverkning2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report covers the procedure for measuring cable samples. Cables will have been quality tested and one part of this quality testing is to measure insulation and sheath thickness. This is done by removing a sample from the cable which is measured in a cable measuring device. When the measurement is done the statistics are saved in a database. For different reasons unacceptable variations in these measurement statistics occur. This means that a cable can be within the given tolerances in reality, but appears to be outside those tolerances in the statistics because it is compared to the wrong template (article file) by the cable measuring device’s software.

    The purpose of this report is to develop a model guaranteeing that the measurement statistics within the cable measurement database are correct so that in future work with statistical process control can be carried out. Through interviews, observations and data collection the causes of the variations will be investigated.

    The report provides a proposed solution where, through a standardized work procedure, with motivated employees and a committed leadership, it gives the tools to work with statistical process control. This statistical process control provides a means to, among other things, decrease costs resulting from incorrectly sized cables.

  • 317.
    Tesfay Abraham, Bisrat
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Degradation Evaluation of Grid- Connected PV Modules at Högskolan Dalarna Borlänge, Sweden2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study has been carried out to evaluate the degradation of grid connected PV system modules installed at Högskolan Dalarna in Borlänge, Sweden. The system which has two arrays each containing 36 monocrystalline PV modules has been in operation since 1994. The modules from GPV of an average peak power 43.9W were tested for I-V curve characteristics under outdoor conditions using AMPROBE Solar 4000 I-V curve tracer with ±1% accuracy and AMBROBE Solar 4000 Sensor with accuracy of ±5%. Measured electrical parameters (short circuit current, open circuit voltage, and maximum power) were extrapolated to STC following Standards IEC 60904-1 for I-V curve measurement and IEC 60891 for temperature and solar irradiation corrections. Thus, values extrapolated to STC were compared with nominal values to calculate global power degradation.

    An average global power degradation showing a standard deviation of 1.6% is found as 11.9% while open circuit voltage and shot circuit current average degradations are 2.5% and 6.4% respectively. Calculated median degradation rate of 0.6% is also compared with a related study median degradation rate of 0.46% per year in similar weather conditions and estimated warranties of 80% of the nominal power after 20 years of operation provided in the 90s. Thus, all the tested modules have a median degradation of 2.5% higher than that of related study and they have shown higher performance as compared to estimated manufacturer’s warranty.

    Regarding degradation modes, visual inspection was carried out on each module, except light yellowing or browning in some modules, no visually visible defects or faults like cell crack, delamination, bubbles, hot spot, and rust in connection boxes were displayed. However, the calculated power degradation, depending on the I-V curves deviations found, is induced because of the possible causes by parasitic resistances, mismatch, ageing, and loss of transparency of encapsulant due to light browning.

  • 318. Thevenot, Henri
    et al.
    Simpson, Timothy
    Jiao, Roger
    Kenger, Patrick
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Product platforming for a global marketplace2008In: Journal of engineering design (Print), ISSN 0954-4828, E-ISSN 1466-1837, Vol. 19, no 6, p. 461-463Article in journal (Refereed)
  • 319.
    Thyr, Max
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Simulation Study of Bifacial PV Modules in Sweden2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    One argument against the usage of PV system is the low energy density. Another common

    argue is the bad possibility to match energy generation and the energy demand in time. A

    solution for these problems could be to use bifacial PV modules. A bifacial PV module can

    generate energy even from the rear side. With this technic more energy can be generated

    per area. In this thesis simulations with bifacial PV modules has been performed for three

    different locations in Sweden. Different tilts, mounting heights and azimuth angles have

    been simulated, all in combination of varying albedo. These cases simulated are Borlänge,

    Jukkasjärvi and Linköping. In Linköping there is a PhD project about bifacial PV modules

    going on. The test field used in that project has been simulated in this simulation study to

    later be compared with measured results.

    In this thesis the simulation tool Polysun was used. Polysun is a user friendly tool and with

    the latest update it’s possible to simulate bifacial PV modules. For all three cases a

    reference system has also been simulated using monofacial PV modules.

    The simulated result suggests that bifacial PV modules should be mounted with the same

    tilt as monofacial PV modules. The orientation should be towards south, the output

    becomes evident decreased if the bifacial PV modules are facing east-west compared to

    south.

    Polysun seems to only take ground reflected radiation into account when calculating the

    rear side energy output when simulations is performed with bifacial PV modules. When

    the albedo is 0 there won’t be an extra output from rear side for all mounting

    combinations. If the bifacial PV module is mounted 0m above ground, there won’t be any

    energy output from the rear side either. This are big limitations in the program.

    In Polysun the simplification is made that it’s the same albedo all year around. It’s not

    possible to do simulations with different albedos. In reality the natural albedo will change

    with the season, especially in Sweden. But those conditions are not possible to simulate. A

    good idea for bifacial modules would be to secure as high albedo as possible by paint or a

    bright canvas.

  • 320.
    Troitiño Malavasi, Bruno Matias
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Replacing Finned Copper withCorrugated Stainless Steel, forthe Heat Exchangers of a SolarCombisystem Store: Performance and EconomicEvaluation2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The importance of investigating cost reduction in materials and components for solar thermal systems is crucial at the present time. This work focuses on the influence of two different heat exchangers on the performance of a solar thermal system. Both heat exchangers studied are immersed helically coiled, one made with corrugated stainless steel tube, and the other made with finned copper tube with smooth inner surface.A test apparatus has been designed and a simple test procedure applied in order to study heat transfer characteristics and pressure drop of both coils. Thereafter, the resulting experimental data was used to perform a parameter identification of the heat exchangers, in order to obtain a TRNSYS model with its corresponding numerical expression. Also a representative small-scale combisystem model was designed in TRNSYS, in order to study the influence of both heat exchangers on the solar fraction of the system, when working at different flow rates.It has been found that the highest solar fraction is given by the corrugated stainless steel coil, when it works at the lowest flow rate (100 l/hr). For any higher flow rate, the studied copper coil presents a higher solar fraction. The advantageous low flow performance of stainless steel heat exchanger turns out to be beneficial for the particular case of solar thermal systems, where it is well known that low flow collector loops lead to enhanced store stratification, and consequently higher solar fractions.Finally, an optimization of the stainless steel heat exchanger length is carried out, according to economic figures. For the given combisystem model and boundary conditions, the optimum length value is found between 10 and 12 m.

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  • 321. Trygg, Louise
    et al.
    Björk, Curt
    Karlsson, Peter
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Djuric Ilic, Danica
    Heat collaboration for increased resource efficiency: A case study of a regional district heating system and a mine2016Conference paper (Other academic)
    Abstract [en]

    To rapidly develop sustainable energy systems is crucial for the whole society's transition towards sustainability. System efficiency and reduced climate impact are important parts of this. Swedish district heating systems are fairly well developed, mainly based on non-fossil fuels, and includes energy-efficient technologies (such as combined heat and power production and fuel gas condensation). Increased use of district heating is therefore considered as a way to increase energy-efficiency, to phase out fossil energy for heating purposes, and subsequently to a reduction of global CO2 emissions. 

    The aim of this paper is to study system impact of increased demand of district heating by analysing a collaboration on heat supply between the local energy supplier of Ludvika in Sweden and a nearby mine. The paper analyses economic potential, as well as the potential for more efficient operation of district heating production plants in the local district heating system. The heat demand in the mine is presently supplied from a small-scale biomass-fuelled heat-only boiler located near to the mine. The system consists of two biomass-fuelled heat-only boilers with fuel gas condensers. The consequences of connecting the heat demand of the mine with the municipal district heating system is analyzed using the cost optimization model MODEST. 

  • 322.
    Trygg, Louise
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ersson, Hans
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gradén, Mattias
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ragnarsson, Marit
    Rehme, Jakob
    Hinder och Drivkrafter: Projekt Branschvis Energieffektivisering2015Report (Other academic)
    Abstract [sv]

    Föreliggande rapport är en del av utvärdering av projektet BEE – Branschvis energieffektivisering.

    Projektet BEE – Branschvis Energieffektivisering

    Projektet genomfördes under 2013-2014 i Dalarna och Gävleborgs län. Projektägare var Länsstyrelsen Dalarna i samarbete med Gävle-Dala Energikontor. Projektet finansierades med medel från Energimyndigheten, Region Gävleborg och Länsstyrelsen Dalarna.

    Samarbete inleddes med små och medelstora industrier (SME) inom följande branscher: sågverk, teknikföretag, träindustrier, kött- och livsmedelsindustrier, alpina skidanläggningar, turisthotell, drivmedelsstationer och livsmedelsbutiker. För varje bransch har projektet anlitat en specialiserad energikonsult som hjälpt företagen med energikartläggningar och gett stöd för planering av åtgärder. 125 företag medverkade i projektet, varav 116 stycken gjorde en heltäckande energikartläggning. Sammanlagt togs mer än 1 750 förslag på åtgärder fram.

    I projektidén för BEE ingick även att engagera energi- och klimatrådgivarna i genomförandet, för att på så sätt bidra till kompetensutveckling. Syftet med projektet var att fokusera på energikartläggningar och genomförande av åtgärder. Själva energikartläggningarna har inte genomförts med finansiering av projektet, utan som en affärsmässig uppgörelse mellan företagen och vald energikonsult.

    Syftet med föreliggande rapport är att studera förutsättningar för en implementering av åtgärder för energieffektivisering som framkommit vid de genomförda energikartläggningarna från projekt BEE. Genom intervjuundersökningar och enkätstudier har drivkrafter och hinder studerats för energieffektivisering samt hur företagen arbetar med internt energieffektivisering. Som komplement till detta är även en analys gjord avseende ekonomiska förutsättning för energieffektivisering i de studerande branscherna (se appendix 1).

    De resultat som presenteras i denna rapport har gjorts med representanter från olika befattningar inom de analyserade industrierna. Alla har gett sin syn på hinder och drivkrafter för energieffektivisering samt hur det interna energieffektiviseringsarbetet fortgår inom deras organisation och hur det kan förbättras.

    Resultat från intervjuundersökningar och enkätstudier visar bl.a. att inom branscherna teknikföretag, kött- och livsmedelsindustrier, alpina skidanläggningar, drivmedelsstationer, turisthotell och livsmedelsbutiker är kostnadsbesparingar är en av de tre främsta gemensamma drivkraften, samt att brist på investeringskapital eller osäkerhet kring investeringsberäkning anges som ett av de främsta hindren för energieffektivisering. Inom branscherna sågverk och träföretag är beteende och attityder rankat som främsta hindret för energieffektivisering samt stöd från högsta ledningen den största drivkraften för att genomföra energieffektiviseringar.

    Resultat från studien visar också att projekt BEE bidragit med ytterligare kunskap om möjligheten att energieffektivisera, samt även att projektet har medfört ett mer aktivt energieffektiviseringsarbete inom den egna organisationen.

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  • 323.
    Tuccella, Simone
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Grid Connection of the Existing Off-grid PV system at Mavuno Secondary School in Tanzania2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The research investigated the grid connection of the existing off-grid PV system at Mavuno Secondary School in Tanzania. The national power grid reached the area during 2015; therefore the grid connection has been studied together with eventual increases of the PV array size. Such research provided a feasibility study in the unexplored topic of connecting stand-alone systems to the national grid once it becomes available.

    The first part of the study aimed to define the load consumptions of the school. On this regard, a measurement system has been set up. It also measured the values of battery state of charge and PV production. The second part involved the modelling and simulations of the system by means of the software HOMER. The existing system has been simulated showing a cost of energy of 0.42 $/kWh. The modelled results showed an overall similarity with the measured values, although some limitations of both measurement system and simulation tools were present. After that, the optimisations of the system regarding future scenarios have been performed. The investigation involved both PV stand-alone and grid connection configurations. Increased load cases and different grid scenarios have been considered. Depending on the load scenarios, the stand-alone system presented a cost of energy between 0.34 $/kWh and 0.55 $/kWh. Instead, depending on load and grid configurations, the grid connected system showed a cost of energy ranging from negative values to 170 $/kWh. The negative values were due to the higher incomes of the sellback compared to the system expenses.

  • 324.
    Turk, Suheyla
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Sustainable Neighbourhood Design in Jakobsgårdarna, Borlänge2019Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy efficient houses benefit communities not only to provide renewable energy shares and generating surplus electricity supporting local economic development. Also, residents in energy efficient houses have less energy usage that reduces household budget expenses. However, one of the obstacles of energy efficient technology installment of residential buildings is high investment cost, which can be solved with the usage of modular housing. In Europe, housing costs have a large share, especially for Sweden, housing expenses is a burden mostly for people who are at the risk of poverty. Also, high investment costs of energy efficient housing are combined with high construction prices leading a large share of budgets and effort to make houses affordable for low income groups. This study develops a scenario to find solutions for affordable housing problem in Sweden with a design proposal. The aim of this study is to investigate if there are ways of achieving socio-economic mix by the production of energy efficient affordable housing and urban gardening to develop a strategy for resource efficiency in Jakobsgårdarna. To achieve the aim, energy efficient affordable housing designed as modular units to achieve a local economic development. This study uses a design-based research method consisting of learning from background cases to transfer lesson learned in design phase of the sustainable neighborhood consisting of energy efficient technologies. Background cases were analyzed with literature review to define sustainable neighborhood, which was then used to develop a hypothesis. Findings of this thesis generates definition of sustainability tools consisting of a collaborative ownership; designing common kitchens; producing electricity and biogas from renewable energy sources; practicing urban agriculture; managing waste and storm and methods to cross subsidize energy efficient affordable housing production. The outcome of this research provides a sustainable neighborhood design proposal for Jacobsgårdarna, Borlänge.

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  • 325. Turk, Suheyla
    et al.
    Quintana, Samer
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Life-cycle analysis as an indicator for impact assessment in sustainable building certification system: the case of Swedish building market2018In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 153, p. 414-419Article in journal (Refereed)
    Abstract [en]

    This paper assesses the prevailing sustainable building certification systems in Sweden, based on a critical analysis of their characterization for human and environmental impacts through the integration of life-cycle analysis. The aim of this study is to compare sustainable building certifications systems in terms of their assessment categories. In the Swedish market, BREEAM SE, LEED, Green Buildings and Miljobyggnad are the most used building certifications. Therefore, their guidelines are reviewed to evaluate which of them has comprehensively included human health indicators. This research presents useful information for transforming existing and developing future sustainable building certification systems.

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  • 326. Udomsri, Seksan
    et al.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Martin, Andrew R.
    Martin, Viktoria
    Decentralized cooling in district heating network: system simulation and parametric study2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 92, p. 175-184Article in journal (Refereed)
    Abstract [en]

    This paper presents system simulation and parametric study of the demonstration system of decentralized cooling in district heating network. The monitoring results obtained from the demonstration were calibrated and used for parametric studies in order to find improved system design and control. This study concentrates on system simulation studies that aim to: reduce the electricity consumption, to improve the thermal COP's and capacity if possible; and to study how the system would perform with different boundary conditions such as climate and load. The internal pumps inside the thermally driven chiller (TDC) have been removed in the new version TDC and implemented in this study to increase the electrical COP. Results show that replacement of the fourth with the fifth generation TDC increases the system electrical COP from 2.64 to 5.27. The results obtained from parametric studies show that the electrical and thermal COP's, with new realistic boundary conditions, increased from 2.74 to 5.53 and 0.48 to 0.52, respectively for the 4th generation TDC and from 5.01 to 7.46 and 0.33 to 0.43, respectively for the 5th generation TDC. Additionally the delivered cold increased from 2320 to 8670 and 2080 to 7740 kWh for the 4th and 5th generation TDC's, respectively. (C) 2011 Elsevier Ltd. All rights reserved.

  • 327.
    Vangari, Divyanagalakshmi Haribabu
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fathima, Sumayya
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Design of Distributed Rooftop PV System to Minimize Power Cuts for an Indian Village2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    India is a developing country. The national energy production is not enough to fulfill the energy demands of the country. Moreover, there are many villages still needs to be electrified. Among the electrified villages, most of them receive only a few hours of electricity each day making it difficult for people residing there. India has excellent potential for the solar power receiving (4 to 7) kWh/m

    2. Therefore, Government of India sets an ambitious target to install 100 GW of solar capacity by 2022, 40 GW is from rooftop solar. The government is encouraging installation of rooftop PV systems by providing several financial incentives to set up rooftop PV system and policies to purchase the energy. However, the people living in rural areas are not capable of utilizing such financial incentives and understand the procedures due to lack of knowledge and financial ability. Thus, a suitable techno-economical model for grid-connected solar rooftop installations for an Indian village by a third-party investor and project developer is investigated in this thesis.

    The design of a grid-connected rooftop PV system with a battery is considered in this thesis. The sizing of PV system and battery are done based on the village annual day and night load demands. A 72 kW PV system consisting of 3 kW each on 24 roofs is considered to meet the village load demand. Two design methods are discussed for power evacuation from the 72 kW PV system, (1) Centralized design and (2) Decentralized design. In centralized design, all the 3 kW PV strings are connected in parallel to a central inverter, which is integrated with the three-phase grid. A central battery bank is installed and charged by an inverter fed by the utility supply. In decentralized design, the 3 kW PV sting on each roof is integrated to the nearby single phase line through a single phase inverter. The battery bank is equally distributed among the 24 houses, and each battery is charged by a single phase inverter fed by the utility supply.

    The techno-economic study of the two methods are performed, and the key technical and economic performance indices are compared. The assumptions are made wherever needed, and the uncertainties in the inputs data and methods and their impact on the results are discussed. A 10 % of uncertainties in the inputs data for simulations and other parameters are considered for evaluating the impact of PV system performance. The annual produced energy, specific production, and performance ratio for centralized design are 102 MWh, 1411 kWh/kW, and 0.73 respectively. The corresponding performance indices for decentralized design are 108 MWh, 1498 kWh/kW, and 0.77 respectively. The levelized cost of energy and payback period for the centralized design is 3.23 INR and 8 years whereas for decentralized design are 3.13 INR and 7 years for decentralized design by considering 50 % subsidy on the capital cost of the PV system. The payback period increases to 15 years for centralized design and 13 years for decentralized design without any capital subsidy. Therefore, capital subsidy makes the project more attractive to the project investor. The technical and economic performance of the 72 kW PV system with the decentralized design is better than the centralized design, without considering the impact of uncertainty. However, after considering both the positive and negative variation of uncertainty (± 10 %), it is difficult to comment on which design has the better results because both designs have nearly equal range of results.

    The underlying limitations of the study are highlighted, and their impact on the results are discussed. The main limitations are the accurate estimation of load profile and boundary conditions of the village (such as actual dimensions of the house, orientation, and tilt angle of the roofs) to perform the simulations.

    The relevant previous work is cited at appropriate places in the report.

  • 328.
    Vennerberg, Patrik
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Improvement of Routine Test Process of High Voltage Power Capacitors2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The capacitor test process at ABB Capacitors in Ludvika must be improved to meet future demands for high voltage products. To find a solution to how to improve the test process, an investigation was performed to establish which parts of the process are used and how they operate. Several parts which can improves the process were identified. One of them was selected to be improved in correlation with the subject, mechanical engineering. Four concepts were generated and decision matrixes were used to systematically select the best concept. By improving the process several benefits has been added to the process. More units are able to be tested and lead time is reduced. As the lead time is reduced the cost for each unit is reduced, workers will work less hours for the same amount of tested units, future work to further improve the process is also identified. The selected concept was concept 1, the sway stop concept. This concept is used to reduce the sway of the capacitors as they have entered the test facility, the box. By improving this part of the test process a time saving of 20 seconds per unit can be achieved, equivalent to 7% time reduction. This can be compared to an additional 1400 units each year.

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  • 329.
    Verma, Pankaj
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Water saving comparison study between innovative and conventional cleaning systems for CSP technologies2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
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  • 330.
    Vestlund, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Dalenbäck, Jan-Olof
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Movement and mechanical stresses in sealed, flat plate solar collectors2012In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 86, no 1, p. 339-350Article in journal (Refereed)
    Abstract [en]

    This article describes movements and mechanical stresses in sealed, gas-filled, flat plate solar collectors. The advantage of a sealed space between a collector absorber and glass cover is that it (i) eliminates the influence of humidity condensation and dust and (ii) it lowers the heat losses when the enclosed space is filled with a suitable gas at normal pressure. However as the solar collector temperature varies, volume and pressure changes cause movement and mechanical stresses. In this study, the finite element method was used to determine movements and mechanical stresses. Several geometries were analyzed and it was found that the stresses in the investigated collectors are a factor 2–4 below the critical stress levels. Furthermore, it was found to be possible to reduce the stresses and improve the factor of safety by (i) using a larger area and/or reducing the distance between the glass and the absorber and/or (ii) changing the length and width so the tubes are longer.

  • 331.
    Vestlund, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Dalenbäck, Jan-Olof
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Thermal and mechanical performance of sealed, gas-filled, flat plate solar collectors2012In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 86, no 1, p. 13-25Article in journal (Refereed)
    Abstract [en]

    The study includes calculations for both the thermal performance and the mechanical behaviour of a gas-filled, flat plate solar collector without external gas expansion, i.e., a collector with varying gas volume and gas pressure and movement in both cover glass and absorber. Classical theories for the thermal performance are combined with a finite-element method to investigate which factors have an impact from the mechanical stress point of view. This article describes major results for collectors with copper and aluminium absorbers combined with different inert gases. It is shown that a collector may be designed which uses less material than a standard collector but achieves at least the same thermal performance, by using a thinner collector and a thinner absorber and a suitable gas filling other than air. If copper is used in absorber and tubes, a 0.15 mm thick absorber together with a tube-to-tube distance of 103 mm results in the same performance as a 0.3 mm absorber with a 144 mm tube-to-tube distance, but the former will use 25% less material. The use of copper can be further reduced if the absorber is made of aluminium and the tubes are made of copper. The factor of safety for thick (>0.5 mm) aluminium absorbers is, however, not as large as it is for copper absorbers.

  • 332.
    Vestlund, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Dalenbäck, Jan-Olof
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Thermal losses in sealed, gas-filled flat plate solar collectors2007In: Solar World Congress, Peking, 2007, Vol. 1, p. 651-655Conference paper (Other academic)
    Abstract [en]

    A sealed space between absorber and cover glass makes it possible reducing the influence of humidity condensate and dust at the same time as the enclosed space can be filled with a suitable gas for lowering the losses. This paper is about the size of the losses in these collectors. A calculating model of a gas-filled flat plate solar collector was built in Matlab with standard heat transfer formulas. It showed that the total loss can be reduced up to 20% when changing to an inert gas. It is also possible using a much shorter distance and still achieve low losses at the same time as the mechanical stresses in the material is reduce.

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  • 333.
    Vestlund, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Dalenbäck, Jan-Olof
    Thermal performance of gas-filled flat plate solar collectors2009In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 83, no 6, p. 896-904Article in journal (Refereed)
    Abstract [en]

    A sealed space between absorber and cover glass in a flat plate solar collector makes it possible to reduce the influence of humidity condensate and dust at the same time as the enclosed space can be filled with a suitable gas for lowering the heat losses. This article describes the influence of different gases on the heat losses in a typical flat plate solar collector. A model of a gas-filled flat plate solar collector was built in Matlab with standard heat transfer formulas. The results show that the overall heat loss can be reduced by up to 20% when changing from air to an inert gas. It is further possible to reduce the distance between absorber and cover in order to reduce the mechanical stresses in the material with similar heat losses.

  • 334.
    Vidal Lorbada, Ricardo
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Design and implementation of a charge controller with buck converter topology for a Li-ion battery using the component LTC4015.2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report presents the process of design and implementation of a battery charger for a Li-ion battery. The development of this battery charger includes the component from Linear Technology LTC4015. This component integrates the functions of a battery charger configured as a buck (step-down) converter. This device must be integrated in a Printed Circuit Board with a specific design. Also, it must be configured using a microcontroller named Raspberry Pi, which also performs the measurements.

    The method of design is divided in two parts. One is focused on developing the printed circuit board, which includes the simulation of the device and the development of the PCB, and the second one is focused on developing the program used in the microcontroller to manage the operation of the LTC4015.

    The result is a charge controller device that can be used with different configurations with a buck converter topology. The different parts of the design process are the simulation, the design and the implementation. Each of these parts have a section of results in this report. The simulation section includes results obtained with LTSpice and the device LTC4020, which is a similar device to the LTC4015 but without the Maximum Power Point Tracking mode, which is not modelled in LTSpice.

    PV is the main power source considered to charge the battery, and is carefully studied in this project. The PV input is studied with LTSpice, first simulating the I-V curve of the schematic of the solar cell. Second, integrating a solar cell in the simulation of the LTC4015. Third, operating the device LTC4015 with a solar panel that is also characterized.

    The design section includes the electronic components used for the development of the board that integrates the charge controller, the LTC4015 in this case, based on the calculations performed for the requirements of the LTC4015. Finally, the implementation section includes the description of the board implemented but also the description of the configuration and measurement code.

    The conclusions presented in this report show that the LTC4015 is a battery buck charger with different functions that make it suitable to be used in different solar applications. Also, this report opens new future work lines, such as the full characterization of the board, the implementation of a test bench and the integration of the board in different applications for solar energy systems.

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  • 335.
    Vijay Vichare, Rohan
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Evaluation of Two Solar Heating and Cooling Systems2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The main purpose of this study is to compare a heat pump system with a SunCool collector system based on the key performance factors. SunCool collectors are sorption integrated solar thermal collectors which produce both heating and cooling. This analysis is carried out in TRNSYS software. The heat pump system is designed with the PV system and then it’s been simulated in TRNSYS for certain climate conditions. The SunCool collector system has been simulated in the existing TRNSED application by using the TRNSYS input file of the system. The parametric study has also been done to get the ideal size of the system and to check how the system works under different parametric conditions. The results of the simulations have been evaluated in terms of total electric consumption, solar fraction, self-consumption and total energy production. Both systems have been simulated for the location of Madrid, Spain. The same load data has been used in the simulation of these systems.

    A simulation study shows that the heat pump system provides 405 MWh of energy to DHW system per year and 351 MWh of energy to space heating and cooling system per year. The SunCool collector system provides 391 MWH and 101 MWh of energy to DHW and space cooling system respectively. The control system of SunCool collector system doesn’t provide energy to space heating. The heat pump system has a maximum load at night hence during the night it takes electricity from the grid and during the day it gives it back to the grid. Almost 80% of the total electricity load is provided by the grid.

    The comparison study of the simulation results shows that the PV+heat pump system provides the full amount of load while the SunCool collector system provides 97% of DHW load and 51% of cooling load with the same number of collectors. Even though the heat pump provides the full amount of load, the electricity consumption of the system is quite higher at 246 MWh per year although for SunCool collector system it’s just 20 MWh per year. Solar fraction of the SunCool collector system is 64% whereas for heat pump system it’s 17%. Hence to select the feasible option between heat pump system and SunCool collector system, an economic analysis must be done by considering the price of the collectors, feed-in tariff and price of the grid electricity.

  • 336.
    Vijayan, Veenaaishwarya
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Simulation Study for Optimal Inverter Sizing of Grid-Connected PV Systems in Swedish Locations2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In present scenario grid connected photovoltaic systems are widely deployed in towns and cities as they can contribute to better environment. They also have advantage of generating significant quality of energy near the consumption point by avoiding transmission and distribution losses. In any grid connected system one of the main components needed would be the inverter for delivering AC output to the grid. The key issue to have best output merely depends on the sizing of the component. Factors influencing the sizing of the components in the PV system are components technology, climatic aspects of placements of inverter installed and solar radiation distribution characteristics that, of which location and climatologically plays a major role. In places like Sweden and most parts of northern European countries, under sizing of the inverter in PV grid-connected systems is recommended. This is because solar radiation reaches seldom values around 1000 W/m2 which PV modules are rated for. There are also many cloudy days when the inverter would operate in 5-20% of the nominal range where inverter efficiencies are significantly lower than for higher radiation. Thus leading to cost efficient photovoltaic grid connected systems though there might be certain amount of energy losses in the system.

    Operating at higher or lower ranges reduces the efficiencies of inverters to some extend due to technical implications of the device. In this thesis, the optimal sizing factor of inverter will be studied, besides the energy yield, the cost and expected life time of the inverter shall also be taken into account. For more appropriate results three different locations that covers south, middle and north part of Sweden is taken into account. A life cycle analysis is also done based on system yield simulations, data from the literature and cost data provided by the government norms of Sweden.

    The thesis will also investigate on the effect on life time of the inverters data influences the results due to undersize compared to the PV array and how much the maxima smoothes out due the time resolution of the radiation. One hour average data might mislead as it averages out some of the peak radiation. Comparisons between hourly averages and minute wise global solar radiation is done and analyzed.

  • 337.
    Vijayaragavan, Krishna Prasad
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Feasibility of DC microgrids for rural electrification2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    DC system and DC microgrids are gaining popularity in recent times. This thesis suggests a method to state the workability of a DC based PV system using the softwares Simulink, PVsyst and HOMER. The aims of this project include suggesting a DC based architecture, finding out the performance ratio and a cost analysis. The advantages of the DC based system, the cost benefits associated with it and its performance will determine its feasibility.

     

    Not many softwares have the functionality to simulate DC based PV systems. PVsyst is considered as one of the most sought-out softwares for the simulation of PV systems. It can simulate a DC based PV system but has a lot of limitations when it comes to the architecture and voltage levels. Due to these factors, the results from softwares Simulink, Homer and PVsyst are used to calculate the performance ratio of the suggested DC system. 

     

    The simulation of the DC system involves modelling of a DC-DC converter. DC-DC converters are used in HVDC transmission and are being considered for small scale and medium scale microgrids. The DC-DC boost converter is coupled with a MPPT model in Simulink. P and O algorithm is chosen as the MPPT algorithm as it is simple and widely used. The Simulink model of PV array and MPPT based boost converter provides the power output at the needed voltage level of 350V. The input for the Simulink model is obtained from the results of HOMER. The inputs include solar irradiation data and cell temperature. The same input data is used for the simulations in HOMER and PVsyst. The performance ratio is obtained by combining the power output from Simulink with the other aspects of the system from PVsyst. The performance ratio is done only for the month of January due to the limitations in Simulink. The performance ratio is found out to be 65.5 %.

     

    The cost estimation is done for the distribution and power electronics aspects of the system. It is found out that the cost associated with the conductors will have an impact on the total cost

    only if the conductors used for distribution is more in length. The cost associated with the power converters will make a difference in total cost only if the system is within the range of 100kW. The study shows the workability of the PV based DC system based on the above mentioned aspects

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  • 338.
    Walusimbi Kizanyiro, Samuel
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Soiling Effects on Photovoltaic Modules, Modelling of Specific Cleaning Frequency Optimization for a 10 MW PV Power Plant inTororo, Uganda2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The accumulation of dust on the photovoltaic (PV) modules for the PV plant result in energy loss and therefore, there was a need to assess the impact of soiling on the PV modules since soiling losses are location specific. In this work, the approach of quantifying soiling loss experimentally which involved comparing the temperature corrected short circuit current values for the naturally soiled string to the frequently cleaned string had higher accuracy than the method of extracting soiling loss from the PV plant production data. This was due to the uncertainties associated with the plant production data.

    The average soiling loss values were determined experimentally and from the plant production data. The month of January 2018 was found to have the highest soling loss of 6 % and March 2018 had the lowest soiling loss was less than 1 %. The soiling for the month of January 2018 was used to determine an optimum cleaning interval which balances out with the revenue lost due to soiling and the cost of the cleaning event using the cleaning schedule model and the optimum interval was 21 days from the last date when the plant last cleaned. This optimum cleaning interval reduces the total cost per unit energy generated by the PV plant and therefore, the levelized cost of electricity. However, the optimum cleaning interval may vary depending on the cost of the cleaning event as well as the seasonal variations in the soiling loss and energy generated. The cleaning schedule model developed can be used to determine when the PV plant should be cleaned. However, this model should be used as a guideline since soiling loss highly depends on the climate of the area and it is always changing.

  • 339. Wang, Xinru
    et al.
    Xia, Liang
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Copertaro, Benedetta
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Pan, Song
    Wu, Jinshun
    A systematic review of recent air source heat pump (ASHP) systems assisted by solar thermal, photovoltaic and photovoltaic/thermal sources2020In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 146, p. 2472-2487Article in journal (Refereed)
  • 340. Wei, Yixuan
    et al.
    Xia, Liang
    Pan, Song
    Wu, Jinshun
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Han, Mengjie
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhang, Weiya
    Xie, Jingchao
    Li, Qingping
    Prediction of occupancy level and energy consumption in office building using blind system identification and neural networks2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 240, p. 276-294Article in journal (Refereed)
    Abstract [en]

    Occupancy behaviour plays an important role in energy consumption in buildings. Currently, the shallow understanding of occupancy has led to a considerable performance gap between predicted and measured energy use. This paper presents an approach to estimate the occupancy based on blind system identification (BSI), and a prediction model of electricity consumption by an air-conditioning system is developed and reported based on an artificial neural network with the BSI estimation of the number of occupants as an input. This starts from the identification of indoor CO2 dynamics derived from the mass-conservation law and venting levels. The unknown parameters, including the occupancy and model parameters, are estimated by using a frequentist maximum-likelihood algorithm and Bayesian estimation. The second phase is to establish the prediction model of the electricity consumption of the air-conditioning system by using a feed-forward neural network (FFNN) and extreme learning machine (ELM), as well as ensemble models. To analyse some aspects of the benchmark test for identifying the effect of structure parameters and input-selection alternatives, three studies are conducted on (1) the effect of predictor selection based on principal component analysis, (2) the effect of the estimated occupancy as the supplementary input, and (3) the effect of the neural network ensemble. The result shows that the occupancy number, as the input, is able to improve the accuracy in predicting energy consumption using a neural network model.

  • 341. Wei, Yixuan
    et al.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Shi, Yong
    Xia, Liang
    Pan, Song
    Wu, Jinshun
    Han, Mengjie
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhao, Xiaoyun
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    A review of data-driven approaches for prediction and classification of building energy consumption2018In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 82, no 1, p. 1027-1047Article in journal (Refereed)
    Abstract [en]

    A recent surge of interest in building energy consumption has generated a tremendous amount of energy data, which boosts the data-driven algorithms for broad application throughout the building industry. This article reviews the prevailing data-driven approaches used in building energy analysis under different archetypes and granularities, including those methods for prediction (artificial neural networks, support vector machines, statistical regression, decision tree and genetic algorithm) and those methods for classification (K-mean clustering, self-organizing map and hierarchy clustering). The review results demonstrate that the data-driven approaches have well addressed a large variety of building energy related applications, such as load forecasting and prediction, energy pattern profiling, regional energy-consumption mapping, benchmarking for building stocks, global retrofit strategies and guideline making etc. Significantly, this review refines a few key tasks for modification of the data-driven approaches in the context of application to building energy analysis. The conclusions drawn in this review could facilitate future micro-scale changes of energy use for a particular building through the appropriate retrofit and the inclusion of renewable energy technologies. It also paves an avenue to explore potential in macro-scale energy-reduction with consideration of customer demands. All these will be useful to establish a better long-term strategy for urban sustainability.

  • 342.
    Welander, Isak
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Development of modular attachment for coupler support and centering2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When a train is passing or coupling in a curve or slope on the track it is important that the train coupling can move freely side and height wise. It is also important that the train coupler stays in a centered position when uncoupled, for this purpose there is a support and centering module in Dellner Couplers train couplers. This module contains a part, the front bracket, which main task is to fasten two support dampers to the train couplers main damper. The task was to develop a front bracket that is applicable no matter what other modules that make up the individual train coupler and produce a basis for prototype manufacturing.

     

    This paper shows the entire development process in detail, it describes the methods used, how they were used and what conclusions were drawn from this. Performed calculations are also shown in the appendices.

     

    The result consists of a fully developed front bracket and a basis for prototype manufacturing. The basic concept behind the new front bracket is the same as for the current one but it contains some new solutions. The developed front bracket will not be applicable in all the possible combinations as the task implied, it seems to be impossible to develop such a bracket. Therefore the result also includes ideas for how other parts of the support and centering module should be developed in the future to create a solution that is applicable in all the possible cases. These solutions should be investigated in accordance with a proposed process for the future work.

  • 343.
    Weldemariam, Ashenafi
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Analyzing the Effect of Soiling on the Performance of a Photovoltaic System of Different Module Technologies in Kalkbult, South Africa2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The fact that most of the large scale solar PV plants are built in arid and semi-arid areas

    where land availability and solar radiation is high, it is expected the performance of the PV

    plants in such locations will be affected significantly due to high cell temperature as well as

    due to soiling. Therefore, it is essential to study how the different PV module technologies

    will perform in such geographical locations to ensure a consistent and reliable power

    delivery over the lifetime of the PV power plants.

    As soiling is strongly dependent on the climatic conditions of a particular location a test

    station, consisted of about 24 PV modules and a well-equipped weather station, was built

    within the fences of Scatec’s 75 MW Kalkbult solar PV plant in South Africa.

    This study was performed to a better understand the effect of soiling by comparing the

    relative power generation by the cleaned modules to the un-cleaned modules. Such

    knowledge can enable more quantitative evaluations of the cleaning strategies that are

    going to be implemented in bigger solar PV power plants.

    The data collected and recorded from the test station has been analyzed at IFE, Norway

    using a MatLab script written for this thesis project. This thesis work has been done at

    IFE, Norway in collaboration with Stellenbosch University in South Africa and Scatec

    Solar a Norwegian independent power producer company.

    Generally for the polycrystalline modules it is found that the average temperature

    corrected efficiency during the period of the experiment has been 15.00±0.08 % and for

    the thin film-CdTe with ARC is 11.52% and for the thin film without ARC is about

    11.13% with standard uncertainty of ±0.01 %.

    Besides, by comparing the initial relative average efficiency of the polycrystalline-Si

    modules when all the modules have been cleaned for the first time and the final relative

    efficiency; after the last cleaning schedule which is when all the reference modules E, F, G,

    and H have been cleaned for the last time it is found that poly3 performs 2 % and 3 %

    better than poly1 and poly16 respectively, poly13 performs 1 % better than poly15 as well

    as poly5 and poly12 performs 1 % and 2 % better than poly10 respectively. Besides, poly5

    and poly12 performs a 9 % and 11 % better than poly7. Furthermore, there is no change

    in performance between poly6 and poly9 as well as poly4 and poly15. However, the

    increase in performance of poly3 to poly1, poly13 to poly15 as well as poly5 and poly12 to

    poly10 is insignificant.

    In addition, it is found that TF22 perform 7% better than the reference un-cleaned module

    TF24 and similarly; TF21 performs 7% higher than TF23. Furthermore, modules with

    ARC glass (TF17, TF18, TF19, and TF20) shows that cleaning the modules with only

    distilled water (TF19) or dry-cleaned after cleaned with distilled water(TF20) decreases the

    performance of the modules by 5 % and 4 % comparing to its respective reference uncleanedmodules TF17 and TF18 respectively.

    Download full text (pdf)
    fulltext
  • 344.
    Wiklund, Joakim
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Produktutveckling av pressram för slangpress2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A frame for a crimping machine is developed primary to reduce the manufacturing cost of the frame. This is done by designing a component that uses another method of manufacturing, laser cutting, and multiple thinner components, in the tested cases it is 8 components. There are possibilities to use more or less components depending on situation. The shape of the original frame is kept since after testing it is the most efficient one. The tests with less material on the outermost plates lost stability and thereby got deformed too much in the most cases tested.

  • 345.
    Win, Kaung Myat
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Emissions from residential wood pellet boilers and stove characterized into start-up, steady operation and stop emissions2014In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, no 4, p. 2496-2505Article in journal (Refereed)
    Abstract [en]

    Gaseous and particulate emissions from three residential wood pellet boilers and a stove were characterized and quantified at start-up, steady (full, medium and low combustion power), and stop phases. The aim was to characterize the emissions during the different phases of boiler operation and to identify when the major part of the emissions occur to enable actions for emission reduction where the savings can be highest. The investigated emissions comprised carbon monoxide (CO), nitrogen oxide (NO), total organic carbon (TOC), and particulate matter (PM 2.5). In this study, particle emissions were characterized by both number and mass concentration. The emission characteristics at high combustion power were relatively similar for all tested devices while significant differences in CO and TOC were observed at lower combustion power. Highest CO and TOC emissions are produced by the bottom fed boiler at low combustion power. The accumulated start-up emissions of the tested devices varied in the ranges of 0.5−12 g CO, 0.1−0.7 g NO, 0.1−2 g TOC, 0.12−2.9 g PM2.5, and 2.4 × 1013 to 3.1 × 1014 particles PM2.5. The accumulated stop emissions varied in the ranges 4−15.5 g CO, 0.01−0.11 g NO, 0.02−1.6 g TOC, 0.1−1.3 g PM2.5, and 3.3 × 1013 to 1.4 × 1014 particles PM2.5. The bottom fed boiler B1 had higher start-up and stop emissions than the tested top fed boilers and more particle emissions were accumulated in start-up phase than in stop phases of boiler B1, B3, and stove S1. Number of particles emitted from residential wood pellet combustion is dominated by fine particles smaller than 1 μm and similar particle distribution both in number and mass were observed for the tested devices. The start-up phase generated higher accumulated particle mass than the stop phase.

  • 346.
    Win, Kaung Myat
    et al.
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Particles and gaseous emissions from realistic operation of residential wood pellet heating systems2012In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 59, p. 320-327Article in journal (Refereed)
    Abstract [en]

    Gaseous and particulate emissions from six residential wood pellet heating systems are determined at a realistic six day operation sequence. The study aims to investigate the total emissions from a realistic operation of the heating systems including start-up and stop phases. Five combined solar and pellet heating systems and one reference boiler without solar system with an integrated DHW preparation was tested in a laboratory at realistic operation conditions. The investigated emissions comprised carbon monoxide (CO), nitrogen oxide (NO), total organic carbon (TOC) and particulate matter (PM2.5). In this study, the emissions are presented as accumulated total emissions from the whole six days period and the emissions from start-up and stop phases are also presented separately to evaluate the influence of the emissions from these phases on the total emissions. Emission factors of the measured systems from the six day period are between 192 and 547 mg MJ1 for the CO emissions, between 61 and 95 mg MJ1 for the NO, between 6 and 45 mg MJ1 for the TOC, between 31 and 116 mg MJ1 for the particulate matter and between 2.1 × 1013 and 4 × 1013 for the number of particles. The emissions from the start-up and stop phases are significantly high for the CO (63–95 %) and the TOC (48–93 %). NO and particles emissions are shown to dominate during stationary operation. However, 30–40 % of the particle emissions arise from the start and stop periods. It is also shown that the average emissions of CO, TOC and particles under the realistic annual conditions were higher than the limit values of two eco labels.

  • 347. Wu, J.
    et al.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Shen, Jingchun
    University of Nottingham, Ningbo.
    Wu, Y.
    Connelly, K.
    Yang, T.
    Tang, L.
    Xiao, M.
    Xu, P.
    Wang, H.
    A review of thermal absorbers and their integration methods for the combined solar photovoltaic/thermal (PV/T) modules2017In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 75, p. 839-854Article in journal (Refereed)
    Abstract [en]

    Thermal absorbers and their integration methods are critical to solar photovoltaic/thermal (PV/T) modules. These two elements directly influence the cooling effort of PV layers and as a result, the related electrical/thermal/overall efficiency. This paper conducts a critical review on the essential thermal absorbers and their integration methods for the currently-available PV modules for the purpose of producing the combined PV/T modules. A brief overview of different PV/T technologies is initially summarized, including aspects of their structure, efficiencies, thermal governing expressions and their applications. Seven different types of thermal absorbers and four corresponding integration methods are subsequently discussed and summarized in terms of their advantages/disadvantages and the associated application for various PV/T modules. Compared to traditional thermal absorbers, such as sheet-and-tube structure, rectangular tunnel with or without fins/grooves and flat-plate tube, these four types, i.e. micro-channel heat pipe array/heat mat, extruded heat exchanger, roll-bond heat exchanger and cotton wick structure, are promising due to the significant enhancement in terms of efficiency, structure, weight, and cost etc. The appropriate or suitable integration method varies in different cases, i.e. the ethylene-vinyl acetate (EVA) based lamination method seems the best option for integration of PV layer with thermal absorber when compared with other conventional methods, such as direct contact, thermal adhesive and mechanical fixing. Finally, suggestions for further research topics are proposed from five aspects. The overall research results would provide useful information for the assistance of further development of solar PV/T modules with high feasibility for widespread application in energy supply even at district or city-level in the near future. © 2016 Elsevier Ltd.

  • 348. Wu, Yupeng
    et al.
    Parham, Mirzaei
    Zhang, Xingxing
    Fang, Wenbo
    Thermal and optical analysis of a passive heat recovery and storage system for building skin2016Conference paper (Refereed)
  • 349.
    Wäckelgård, Ewa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Svedung, Harald
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Optical characterization and modelling of paint top-coatings for low-emittance applications2016In: Infrared physics & technology, ISSN 1350-4495, E-ISSN 1879-0275, Vol. 78, p. 275-281Article in journal (Refereed)
    Abstract [en]

    The study reports on characterization of low-infrared-emittance paint top-coatings for interior building applications in which the thermal radiation becomes important in comparison with thermal conductance. The top-coating that consist of a binder with aluminium flakes has been optically characterized in the infrared wavelength range in order to determine single flake and binder emittance from reflectance measurements. The single flake emittance was found to be 0.12 for non-leafing cornflake. The absorption coefficient that determines the binder emittance as a function of binder thickness was 0.060 [μm]−2 and 0.085 [μm]−2 for Lumiflon and polyester respectively. These results were used as parameters in a simple model of the flake-binder top-coating to investigate how the emittance of the top-coating was influence by the two components and compared with a state-of-art low-emittance commercial paint. It was found from the modelling that replacing the polyester binder with Lumiflon reduces the infrared emittance (at room temperature) from 0.36 to 0.30. Increasing flake reflectance from 0.88 to 0.96 and at the same time reduce flake thickness from 2 to 1 μm gives an emittance of 0.20. However, the real samples prepared with Lumiflon showed a severe degradation caused by the flakes floating up closer to the surface which indicates a viscosity problem that needs to be solved for practical use. Thinner flakes with higher reflectance can be found if vacuum metallised pigments are used instead of ball-milled.

  • 350. Xiao, M
    et al.
    Tang, L
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Yu-Fat-Lun, I
    Li, G
    Analysis on cooling technologies of concentrated solar power system: a review2017Conference paper (Refereed)
    Abstract [en]

    The application of the Concentrated Solar Power (CSP) system has attracted an ever-increasing attention with the deepening worldwide energy crisis. Operating temperature is one of the most important factors for CSP system that affects the solar photoelectric conversion efficiency. Reasonable cooling method cannot only decrease the operative temperature, balance flare inhomogeneity, also should display the characteristics of convenient installation, low power consumption and high reliability. Based on a comprehensive literature review, this work conducted a thorough compilation on different cooling techniques of CSP system. It includes the commonly used air cooling and water cooling, also illustrates the promising ground coupled cooling, impinging jet cooling, liquid immersion cooling, microchannel cooling, heat pipe cooling and Phase Change Material systems etc. Besides, the advantages and disadvantages of different cooling technologies are briefly analysed. It is expected that this paper could provide guidance for development and optimization of cooling technologies in CSP system.

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