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  • 251.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Keus van de Poll, Marijke
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Wigö, Hans
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Ljung, Robert
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Sörqvist, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi. Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University, Sweden.
    The effect of heat stress on writing performance in a classroom2014Inngår i: Indoor Air 2014 - 13th International Conference on Indoor Air Quality and Climate, 2014, s. 183-188Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Studies have shown that heat stress impairs performance. This depends on the mental loading capacity of the task performed and the exposure time. This is a study of a common task in schools and offices: writing task. It also analyses the occupants’ perceived thermal comfort. The experiment was done in two heat conditions: 20 and 25 centigrade. The between participant design was used. ScriptLog was used to perform the writing task, while questionnaires and a Sudoku task were paper based tasks. The results show that the predicted mean vote (PMV) between conditions was significant (p<0.02) and participants perceived the 20 º C condition to be draughty. They however preferred a little more air movements in both conditions. Writing performance only showed a significant difference (p = 0.03) on deleted characters but the other variables considered did not show any significant differences but showed a strong tendency that with a long exposure time it would eventually be impaired.  This shows that writing despite being a complex task is not a high mental loading task and is not quickly impaired by heat stress.

  • 252.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Liu, Shichao
    University of California, Berkeley, USA.
    Schiavon, Stefano
    University of California, Berkeley, USA.
    Potential adaptive behaviour to counteract thermal discomfort in spaces with displacement ventilation or underfloor air distribution systems2016Inngår i: Proceedings of the 14th international conference of Indoor Air Quality and Climate, Ghent, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Building occupants behave in various adaptive ways to restore thermal comfort when in a state of thermal discomfort. These adaptive actions affect building energy use and indoor environmental quality. This paper reports part of a draft risk study, here we focus on potential adaptive behaviour to counteract discomfort in rooms with displacement ventilation (DV) and underfloor air distribution (UFAD) systems. The most likely adaptive behaviours to be taken are: adjust clothing, open/close windows, adjust thermostat and change workstation. No conclusive relationship was found on whether these behaviours are influenced by overall or ankle thermal sensation. Females stated more frequently than males that they would open/close windows, while more males expressed the intention to use heaters and complain to building managers.

  • 253.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Entrainment and its Implications on Microclimate Ventilation Systems: Scaling the Velocity and Temperature Field of a Round Free Jet2019Inngår i: Indoor Air, ISSN 0905-6947, E-ISSN 1600-0668, Vol. 29, nr 2, s. 331-346Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Research on microclimate ventilation systems, which mostly involve free jets, point to delivery of better ventilation in breathing zones. While the literature is comprehensive, the influence of contaminant entrainment in jet flows and its implications on the delivery of supplied air is not fully addressed. This paper present and discuss entrainment characteristics of a jet issued from a round nozzle (0.05 m diameter), in relation to ventilation, by exploring the velocity and temperature fields of the jet flow. The results show a trend suggesting that increasing the Reynolds number (Re) reduces ambient entrainment. As shown herein, about 30% concentration of ambient air entrained into the bulk jet flow at Re 2541 while Re 9233 had about 13% and 19% for Re = 6537/12026 at downstream distance of 8 diameters (40 cm). The study discusses that “moderate to high” Re may be ideal to reduce contaminant entrainment, but this is limited by delivery distance and possibly the risk of occupant discomfort. Incorporating the entrainment mixing factor (the ratio of room contaminants entrained into a jet flow) in performance measurements is proposed and further studies are recommended to verify results herein and test whether this is general to other nozzle configurations.

  • 254.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Wigö, Hans
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Measurement of Entrainment into an Axisymmetric Jet using Temperature as a Tracer: A Pilot Study2018Inngår i: Excellent Indoor Climate and High Performing Ventilation / [ed] Risto Kosonen, Mervi Ahola and Jarkko Narvanne, 2018, s. 397-402Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The current extended abstract is a pilot study of an ongoing experimental and theoretical investigation of ambient entrainment of room air into an axisymmetric free jet using temperature as a tracer. The project aims to investigate, by revisiting the concepts and fundamentals of axisymmetric free Jets and entrainment in ventilation applications, particularly focusing on how to optimize performance of low mixing air distribution systems and to test methods of measuring entrainment in such systems. The study aims to explore a scalar field method using temperature as a tracer to estimate entrainment in axisymmetric free Jets. The results obtained show jet characteristics that slightly differ from what is reported in velocity field measurements and other scalar field studies. Thus, a call is made herein for further investigations to understand entrainment and appropriate methods to determine jet characteristics and its mixing effect. Additionally, more studies are needed to verify whether earlier results are representative of entrainment conditions for low mixing ventilation systems whose operation mode depend on near-filed characteristics of jets.

  • 255.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Center for the Built Environment, University of California, Berkeley, Berkeley CA, USA.
    Wigö, Hans
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Experimental Evaluation of Intermittent Air Jet Ventilation Strategy: Cooling effect and the associated energy saving2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The potential to reduce building energy demand is high especially on building services like ventilation and air conditioning. This potential lies in identifying ventilation strategies that can provide both the required indoor climate and lower the energy use. One of the strategies is optimizing elevated air movements to enhance human convective and evaporative cooling which, as shown in literature, results in reduced energy use on cooling. This paper evaluates the cooling potential and the resulting energy saving of a novel air supply system called intermittent air jet strategy (IAJS). As shown in this study, IAJS with velocities of 0.4 m/s at the breathing height provides a cooling effect equivalent to reducing the ambient temperature in a mixing ventilation system by up to 1.5 oC to achieve a neutral sensation. This translates to a 13% reduction on the cooling demand. The strategy is also shown to have an energy saving potential of up to 50% on the supply fan. 

  • 256.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Center for the Built Environment, University of California, Berkeley, Berkeley CA, USA.
    Wigö, Hans
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Keus van de Poll, Marijke
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Ljung, Robert
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Sörqvist, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    The influence of heat, air jet cooling and noise on performance in classrooms2015Inngår i: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 14, nr 3, s. 321-332Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The quality of indoor environments influences satisfaction, health, and work performance of the occupants. Additional understanding of the theoretical and practical value of individual indoor parameters in relation to health and performance aids indoor climate designers to obtain desired outcomes. This also results in expenditure savings and increased revenue: health care and improved productivity. Here, we report two experiments that investigated how heat, cooling strategy and background noise influence performance in a full-scale classroom mockup setting. The results show that heat and background noise are detrimental to logic-based tasks and to writing, whilst cooling manipulations can protect performance. Implications for indoor environment design are discussed.

  • 257.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Wigö, Hans
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Ljung, Robert
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Sorqvist, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi. Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University, Sweden.
    Perception of intermittent air velocities in classrooms2014Inngår i: Indoor Air 2014 - 13th International Conference on Indoor Air Quality and Climate, 2014, s. 189-191Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Classrooms normally host a large number of people and the heat generated provides a challenge cool. Traditional cooling methods by increased low temperature supply airflow rate or use of heat sinks are expensive and mostly inefficient. The strategy of controlled air movements in the occupied zone may prove cheaper and desirable. This research investigates recirculation of room air to provide intermittent velocity cooling in classrooms. The objective of this experiment was to assess how occupants perceive the recirculated intermittent air velocity conditions in classrooms and when the variations should be introduced in the room for optimal results. This was done with a between participant design, accessing how they perceived indoor air quality (IAQ) and the thermal comfort in two velocity conditions: constant low air velocity condition (< 0.15 m/s) and intermittent air velocity condition (0.4 m/s). As shown here; intermittent air velocity has a positive effect on the perceived thermal comfort (p < 0.04) and perception of air quality: less draughty and improved humid perception. The participants perceived the conditions with intermittent velocity to give comfortable feelings and better air quality.  The variations also showed better performance if they were provided at the start of occupancy as opposed to during or after a temperature build up. This strategy can be used in environments where it is rather uneconomical to provide cooling like spaces hosting a group of people: movie theatres, auditoriums, classrooms and perhaps in restaurants.

  • 258.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Wigö, Hans
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Ljung, Robert
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Sörqvist, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Experimental evaluation of an intermittent air supply system – Part 2: Occupant perception of thermal climate2016Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 108, s. 99-109Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A newly proposed intermittent air jet strategy (IAJS) provides satisfactory indoor climate while promising a substantial energy saving potential, as shown in technical (objective) measurements. The strategy creates non-uniform airflow and non-isothermal conditions critical for sedentary operations at elevated temperatures. The current study explored human perception of thermal environment under an IAJS. Assessment of thermal sensation, thermal comfort, and thermal acceptability were collected based on responses from 36 participants. Participants sat in a classroom setup and performed sedentary work. Their clothing had an insulation of 0.51 clo (T-shirt on upper body). Participants were exposed to homogeneous (v < 0.15 m/s) and nonhomogeneous (0.4 m/s < v < 0.8 m/s) velocity conditions across three temperature conditions: 22.5 °C, 25.5 °C and 28.5 °C. The participants found air speeds to be undesirable at lower temperatures, but reported an improved thermal sensation, comfort and acceptability at higher temperatures. As shown here, IAJS generated neutral operable conditions between 24.8 °C and 27.8 °C, within an air speed range of 0.4 m/s to 0.8 m/s. Additionally, air movements induced thermal alliethesia resulting in improved comfort and acceptance of the thermal climate even at lower air speeds in warm temperature conditions. Hence, the current study supports the energy saving potential with IAJS in view of the human perception of the indoor environment.

  • 259.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Center for the Built Environment, University of California, Berkeley, USA.
    Wigö, Hans
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Experimental evaluation of an intermittent air supply system: Part 1: Thermal comfort and ventilation efficiency2016Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 95, s. 240-250, artikkel-id 4263Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Spaces with high occupancy density e.g.; classrooms, auditoriums and restaurants, provide challenges to ventilate at a lower energy use due to elevated temperatures. To meet occupants’ thermal comfort requirements traditional systems use a lot of energy. Alternative ventilation strategies that optimize high air movements in the occupied zone allow human activities at elevated temperatures while attaining improve occupants’ perception and acceptance of the indoor climate at a low energy use. This paper presents an experimental evaluation of a novel ventilation strategy for high occupancy spaces that provides fresh air and thermal comfort in the sitting zone through a controlled intermittent air jet system. The strategy uses ceiling mounted high momentum air jet diffusers (AJD) made from ventilation duct fitted with nozzles that generate confluent jets. The jets coalesce into a single two-dimensional jet which is directed downwards in the sitting zone. This paper presents an experimental evaluation/analysis of the proposed system with regard to ventilation efficiency and thermal comfort measurements in a classroom mockup. Results show that the system qualifies to be used as a primary ventilation system and has local air change index > 1 inside the jet, and a ventilation efficiency > 50%. The system also provides better thermal climate than mixing and displacement ventilation at elevated temperatures.

  • 260.
    Kabanshi, Alan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Yang, Bin
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Sörqvist, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Occupants’ perception of air movements and air quality in a simulated classroom with an intermittent air supply system2019Inngår i: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 28, nr 1, s. 63-76Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The study reported herein builds on occupant response to an intermittent air jet strategy (IAJS), which creates periodic airflow and non-isothermal conditions in the occupied zone.  Previous research has highlighted the benefits of IAJS on thermal climate and supports energy saving potential in view of human thermal perception of the indoor environment. In this study, the goal was to explore occupant acceptability of air movements and perceived indoor air quality, and to determine a way of assessing acceptable air movement conditions under IAJS. Thirty-six participants were exposed to twelve conditions: three room air temperatures (nominal: 22.5, 25.5 and 28.5 oC), each with varied air speeds (nominal: <0.15 m/s under mixing ventilation (MV), and 0.4, 0.6 and 0.8 m/s under IAJS) measured at the breathing height (1.1 m). The results show that participants preferred low air movements at lower temperatures and high air movements at higher temperatures. A model to predict percentage satisfied with intermittent air movements was developed, and predicts that about 87% of the occupants within a thermal sensation range of slightly cool (-0.5) to slightly warm (+0.5), in compliance with ASHRAE standard 55, will find intermittent air movements acceptable between 23.7 oC and 29.1 oC within a velocity range of 0.4 – 0.8 m/s.  IAJS also improved participants’ perception of air quality in conditions deemed poor under MV. The findings support the potential of IAJS as a primary ventilation system in high occupant spaces such as classrooms. 

  • 261.
    Kahandagamage, Gayan Asanka
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik. Royal Institute of Technology.
    Theoretical and Practical analysis of the effect of charge air temperature and humidity in the combustion process of diesel engines at Heladhanavi Power Plant, Puttalam, Sri Lanka2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Heladhanavi 100MW Diesel Power Plant in Puttalam, Sri Lanka comprises of six 18V 46 Wartsila turbocharged air cooled engines. Fuel consumption of the engines varies with the ambient conditions. It has been seen in hotter days fuel consumption is higher comparatively to cooler days.

    This study was conducted as per the requirement to find out the reasons behind this variation of the fuel consumption and to quantify the effects on the efficiency with respect to the charge air properties in relation to temperature and humidity.

    In this study the effect of charge air temperature was analyzed performing two sets of experiments. A combustion analysis experiment (experiment 1) was performed to monitor what happens inside the combustion chamber during day and night times. This is to investigate the cause of efficiency variation and why and how it happens. Simultaneously a fuel consumption test was performed using the direct method with the fuel flow meter and energy dispatch readings taking in to the consideration. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion.

    A flue gas analysis test (experiment 2) was performed to determine the efficiency variation in day and night times through the indirect method. Along with this analysis the direct method was followed up to calculate fuel consumption to compare the results from the both tests. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion.

    For all the tests and analysis DG 02 at approximately Rhs: 55,000 was selected to conduct the measurements as 48,000 rhs major overhaul was completed recently. All the components in the fuel system such as pumping elements and injectors are in good condition. The cylinder head, liner and piston overhaul was also have been carried out. The experiments were planned so the lots other factors are not affecting the combustion efficiency during the process to isolate the ambient conditions.

    The experiments were also carried out during day and night times on the same day to minimize other factors such as fuel quality affecting the equations. Always the LHV of the incoming fuel was obtained for calculations to avoid further mistakes.

    The results are elaborated along with findings from the past studies in the Literature review.

    It was confirmed the fuel consumption is positively affected by the charge air temperature while the efficiency is negatively affected. From the literature review it was found out the humidity in charge air affects positively on the fuel consumption while efficiency is negatively affected. The charge air temperature affects the ignition delay period so that the peak pressure and then the combustion efficiency. The efficiency improvement is further confirmed by the flue gas analysis experiment as the loss in the flue gas reduces in night time comparatively to the day time.

    At Heladhanavi temperature and humidity in charged air behaves in completely opposite manner in day and night times. During day time temperature is high while humidity is low. For the night time case its vise versa. Finally it can be concluded that under the prevailing ambient conditions at the Heladhanavi Power Plant, Puttalam, Sri Lanka, the effect of charge air temperature is more prominent than the effect of humidity in the combustion process for the Wartsila 18 V 46 diesel engines, as a result the efficiency improves during the night time comparatively to the day time.

    Therefore, proper cleaning and maintaining of the charge air coolers are the most important factor to maintain the charge air temperature and relative humidity inside charge air receiver at a lowest value. Therefore to attain the best electrical efficiency and the fuel consumption for a certain fuel batch.

  • 262.
    Kamaldeen, Mohammed Rizwan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik. Royal Institute of KTH, Sweden.
    Sustainable Energy Source for Water Pumping at Puttalam Salt Limited2014Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The cost of grid based electrical and diesel sea water pumping to salt fields is one of the major cost components out of the total production cost in Puttalam Salt Limited, situated in northern part of Sri Lanka. In order to explore ways and means to improve the energy efficiency and alternative resources to meet the energy requirement a feasibility study was conducted using power system simulation software, (HOMER) and also detailed technical, environmental and financial tools.

     

     This research study is conducted to evaluate the performances and applicability and propose the most suitable sustainable renewable energy source and methodology for water pumping to salt fields instead of currently utilized grid based and fossil fueled energy supply.

     

    Preliminary results obtained by simulation software shows that direct wind mill pumping and solar PV water pumping was found to be unfeasible due to its limited pumping capacity and high investment cost. More over solar PV does not seems much feasible due to its high cost of energy (0.234 US $/kWh) compared to wind powered rivals in this type of applications.

     

    Based on comparisons of the analysis it is seen that the wind/ grid combined configuration of 04 units of AOC15/50 model (50kW manufactured by AOC Renewable Energy - Canada) wind turbine units with 150kw inverter seems to be a logical supplement for water pumping energy requirement than using grid based electricity which costs 0.201 US $/ kWh. The solution in this research affords an attractive 60% annual average renewable fraction as well as an approximate 215.8 tCO2(eq) of annual Carbon Footprint saving. Also it assures a moderate Discounted Payback Period of 6 years and 5months with a 15% of Internal Rate of Return.   

  • 263.
    Karimipanah, Taghi
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik. Faculty of Engineering and Sustainable Development.
    Environmental analysis of cars1988Rapport (Annet vitenskapelig)
  • 264.
    Karimipanah, Taghi
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Larsson, Ulf
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Investigation of flow pattern for a confluent-jets system on a workbench of an industrial space2014Inngår i: Indoor Air 2014: 13th International Conference on Indoor Air Quality and Climate, 2014, s. 192-199Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A new air supply terminal based on confluent jets was installed on a workbench, in vicinity of a CNC machine, of an industrial space. The flow pattern and temperature field was carried out by CFD calculations and infrared camera imaging technique. A main goal of this technique is to save energy therefore the jet should distribute the air where it is desired. This is possible because the confluent jets system uses the benefits of both mixing (high momentum for better spreading of the air jet) and displacement (cleaner air in occupied zone). The results show that thermal comfort and air quality analysis relies on consistent facts and is in good agreements with the existed standards. It was shown that the supply terminal is able to spread the fresh air to the needed work area. This is an advantage of the high momentum air distribution system used in this investigation.

  • 265.
    Karimipanah, Taghi
    et al.
    Department of Thermo- and Fluid Dynamics, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Olsson, Erik
    Department of Thermo- and Fluid Dynamics, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Calculation of three-dimensional boundary layers on rotor blades using integral methods1993Inngår i: Journal of turbomachinery, Vol. 115, nr 2, s. 342-353Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The important effects of rotation and compressibility on rotor blade boundary layers are theoretically investigated. The calculations are based on the momentum integral method and results from calculations of a transonic compressor rotor are presented. Influence of rotation is shown by comparing the incompressible rotating flow with the stationary one. Influence of compressibility is shown by comparing the compressible rotating flow with the incompressible rotating one. Two computer codes for three-dimensional laminar and turbulent boundary layers, originally developed by SSPA Maritime Consulting AB, have been further developed by introducing rotation and compressibility terms into the boundary layer equations. The effect of rotation and compressibility on the transition have been studied. The Coriolis and centrifugal forces that contribute to the development of the boundary layers and influence its behavior generate crosswise flow inside the blade boundary layers, the magnitude of which depends upon the angular velocity of the rotor and the rotor geometry. The calculations show the influence of rotation and compressibility on the boundary layer parameters. Momentum thickness and shape factor increase with increasing rotation and decrease when compressible flow is taken into account. For skin friction such effects have inverse influences. The different boundary layer parameters behave similarly on the suction and pressure sides with the exception of the crossflow angle, the crosswise momentum thickness, and the skin friction factor. The codes use a nearly orthogonal streamline coordinate system, which is fixed to the blade surface and rotates with the blade.

  • 266.
    Karlberg, Anna
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Swedish hydropower: A literature study about Swedish hydropower, environmental impact and EU: s Water Framework Directive 2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    In Sweden, EU: s Water Framework Directive led to an investigation that started in April 2012 by the Swedish government, called Vattenverksamhetsutredningen freely translated to "Water Activities Survey", with the purpose to investigate the Environmental Code’s rules concerning water activities and water plants. The survey is divided into 3 reports, two sub-reports and a final report. One of the sub-report is focused on Swedish hydropower and the investigators found that many hydropower plants have old permits. One suggestion in the survey was to reconsider old permits so they would become consistence with today’s Environmental Code. There have been discussions regarding whether Sweden will lose much of its electricity production from hydropower as an outcome if the survey’s suggestions becomes reality.

    The aim with this literature study is to investigate how the EU: s Water Framework Directive and the Water Activities Survey will affect Swedish hydropower and if there will be a decrease in electricity production as an outcome if the suggestions made in the survey becomes reality.

    The results in this literature study shows that there will probably be a decrease in production for Swedish hydropower, but with how much is hard to say because the Swedish government has not yet decided what they will do with the suggested actions in the Water Activities Survey. A comparison is done with Sweden’s import and export statistics between the years 2001-2014 with a predicted loss of 13 TWh per year, which is a number taken from a survey made by Vattenfall. A comparison with a loss of half of 13 TWh per year is also done. Between the years 2001 and 2014 Sweden imported electricity 6 out of 14 years and exported electricity 8 out of 14 years. If adding the predicted loss of 13 TWh per year to the import and export statistics, Sweden would have had to import electricity 12 years and export 2 years. If adding a loss of 6.5 TWh per year Sweden would have had to import electricity 8 years and export 6 years.

    The conclusions is that Sweden will have to import a lot more electricity if only looking at import and export statistic if the loss of electricity is between 6.5-13 TWh per year.

  • 267.
    Karls, Anna-Lena
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Höglund, Linda
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Effektiv Planering enligt Lean Production: En fallstudie på Sandvik Mining and Construction2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Due to a constantly increasing competitive pressure it is of great importance to constantly strive for improvements in order to gain competitive advantages. Lean Production is a concept that has been introduced with the aim to minimize waste and increase profitability. The purpose of this report is therefore to investigate how to perform effective planning according to the principles of Lean Production, in companys with customer exclusive products, through a case study at Sandvik Mining and Construction (SMC), and to investigate how SMC kan improve their planning of drifting rods at the production unit in Sandviken.

    The study started by creating a theoretical framework, to describe the subject planning and planning based on Lean Production. This frame work constituted the base for the case study which took place at Sandvik Mining and Construction, and also for the model and planning tool that has been introduced.

    The result of the study is partly a general model with factors that contribute to a more effective planning. These factors has beed identifed as SMED, which focuses on reducing set up times and in the end to facilitate the planning. With the assistance of the Pareto rule the amount of items can be grouped together and by that simplify production planning. By using the EOQ, optimized order quantities can be calculated, and thereby simplify for production planning. Even the degree of customer order management is something that affects how the planning can be managed as a high degree of customer order management can simplify for the decision making regarding wich product should be produced, however the time through production can increase. Sequensing is another method that simplifies the planning, as an already predetermined production order shall be produced. The most essential factor is however the motivation of the employees, as this forms the base to able other changes and implement them. Altogether these factors are closely connected to each other and working actively with these can contribute with a simplified planning procedure.

    From without this a tool has been presented in order to simplify the planning of drifting rods at Sandvik Mining and Construction. Through this tool SMC can create a smoother flow through production, a smoother work load, a smoother machine load in the different assembly lines, and in the end reduced adjustment times within the forging press.

  • 268.
    Karlsson, Anna
    et al.
    Luleå Tekniska Universitet.
    Bengtsson, Lars
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Industriell ekonomi. Högskolan i Gävle, Centrum för logistik och innovativ produktion.
    The Managerial Challenge of Setting Goals Conducive to Individual Ambidexterity2017Inngår i: 18th International CINet Conference: Digitalization and innovation: designing the organization of the future, 2017Konferansepaper (Fagfellevurdert)
  • 269. Karlsson, Björn
    et al.
    Lundström, Lukas
    Eriksson, Ola
    Energivärdering av byggnader: Analys av regelstyrd energi- och miljövärdering av byggnader2016Rapport (Annet vitenskapelig)
  • 270.
    Karlsson, Helene
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö.
    Jacobsson, Emma
    Högskolan i Gävle, Akademin för teknik och miljö.
    Nordgren, Thomas
    Högskolan i Gävle, Akademin för teknik och miljö.
    Lean inom sjukvåren: Effektivisering av patientflöde2010Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 271.
    Karlsson, Johan
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Byman, Erik
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Hur påverkar kulturella skillnader mellan Sverige och Kina organisationens arbetssätt?: En fallstudie på Sandvik AB2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    It is important that organizations today focus on continuous improvements in order to face the growing competition in the world. A company needs a corporate culture that supports and encourages the employees to be creative and innovative in their work. This is necessary for the company if they are striving towards continuous learning and development within their organization.

    The main purpose of this paper is to investigate how the culture differences between Sweden and China affect Sandvik AB. We will also study how the company manages continuous improvements and what consequences culture differences have on their work.

    Our paper is a single case study at Sandvik AB in Sweden and China. We have visited Sandvik in Sandviken to conduct a series of interviews with employees of different position within the company and with dissimilar work tasks. We have chosen this procedure to get different angles from the respondents and to acquire depth in our research. After the company visit in Sandviken we had appointments with personal at Sandvik in Beijing, Langfang and Shanghai. These employees also had different position and work tasks within the company.

    After finished study, we can make the conclusion that there exist several culture differences between Sweden and China. Most of these differences can be connected to the national culture. Sandvik where founded in Sweden and therefore they have a Swedish corporate culture. Today the company is a multinational corporation that operates business at the Chinese market and thereby in the Chinese national culture. Because of this situation, we think that it is important that Sandvik finds a balance between the corporate and national culture.

    Today, a new China is emerging. The country has one of the fastest growing economies in the world, this having and will continue to have consequences on Sandvik AB: s organization. In China 20 million students are graduated from the university today and this result in harder competition on the labour market. When more people getting an education, particularly in China, price on knowledge will decrease. The consequence of this will be that the demand of creativity and innovative thinking is rising, especially in Sweden where the labour cost is significantly higher.

  • 272.
    Karlsson, Olle
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Utmattningsanalys av svetsförband på pendelarm tillhörande Eco Logs skördare 590D: jämförelse mellan tre utvärderingsmetoder2012Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Eco Log AB i Söderhamn är en tillverkare av skogsmaskiner. De tillverkar både skotare och skördare. På deras skördare sitter fyra pendelarmar som ersätter hjulupphängningen på fordonet. Dessa motverkar att fordonet lutar vid körning i sluttningar. Varje pendelarm drivs av en hydraulkolv som justerar nivelleringen.

    Då inga beräkningar med avseende på utmattning och livslängd genomförts sedan en omkonstruktion av pendelarmarna är det nödvändigt att analysera och utvärdera pendelarmarna. Syftet med examensarbetet är att analysera ett antal, maximalt tre, av pendelarmens svetsfogar med avsikt på utmattning. Jämförelse mellan de tre olika utvärderingsmetoderna Effective notch stress, Nominell spänning och Hot spot kommer genomföras. På begäran av Eco Log redovisas ej några värden på beräknade livslängder och spänningar utan endast en jämförelse mellan de olika metoderna redovisas där Nominella spännings-metoden används som referensvärde.

    En inledande spänningsanalys på en pendelarm på deras största skördare, Eco Log 590D, genomfördes. Denna analys, där endast en förenklad pendelarm användes, visade att det mest belastade svetsförbandet befann sig i nivå med infästningen av lagret i ytterlådans konstruktion. Detta svetsförband analyserades sedan vidare med avseende på utmattning. De mer noggranna utmattningsanalyserna baserades på tre olika utvärderingsmetoder för spänningar, Hot spot-, Effective notch stress- och Nominella spännings-metoden. Hot spot-metoden inkluderar membranspänningar och böjspänningar för det utvalda svetsförbandet. Effective notch stress inkluderar mebramspänningar, böjspänningar och den olinjära spänningstoppen för att kunna analysera spänningskoncentrationer i svetsrot eller tå. Nominella spänningar inkluderar normalspänningar.

    Genom att modellera det utvalda svetsförbandet med dessa tre metoder erhölls information om den maximala spänningsvidden. Denna spänningsvidd applicerades sedan i en arbetsgång för utmattningsberäkningar där en livslängd beräknades fram. Denna livslängd blev för Nominella och Effective notch-metoden blev densamma och för Hot spot-metoden blev den dubbelt så lång.

    Denna beräkningsgång baseras på International Institute of Welding.Denna beräknade livslängd var betydligt mindre än vad Eco Log hade förväntat sig. Dock är osäkerheten vid beräkningar och test med avseende på utmattning stor och därav borde även provning genomföras för att säkerställa livslängden.

  • 273.
    Karlsson, Thomas
    et al.
    Högskolan i Gävle, Akademin för hälsa och arbetsliv, Avdelningen för arbets- och folkhälsovetenskap, CBF. Högskolan i Gävle, Centrum för belastningsskadeforskning.
    Wijk, Katarina
    Högskolan i Gävle, Akademin för hälsa och arbetsliv, Avdelningen för arbets- och folkhälsovetenskap, CBF. Högskolan i Gävle, Centrum för belastningsskadeforskning.
    Bänziger, Tanja
    Högskolan i Gävle, Akademin för hälsa och arbetsliv, Avdelningen för arbets- och folkhälsovetenskap, CBF. Högskolan i Gävle, Centrum för belastningsskadeforskning.
    A description of work environment management in succesful companies2011Inngår i: Wellbeing and Innovations Through Ergonomics: Proceedings of NES2011, September 18-21, 2011, Oulu, Finland / [ed] Juha Lindfors, Merja Savolainen & Seppo Väyrynen, Nordic Ergonomics Society , 2011, s. 460-465Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A good work environment can support companies' competitiveness, but many managers mostly associate ergonomics with occupational health and safety. In the process of managing the work environment and creating a good working environment, company managers have a central role. This article investigated managers' own descriptions of the work environment management (WEM). The study group consisted of successful companies (n=142) in a county of Sweden. The managers' descriptions were categorised into nine categories. The most frequently described category was “PhysicalFactors at work”, followed by “Manuals and Standardisation”, and “EmployeeInvolvement and Interaction”.

  • 274.
    Kauppi, Kalle
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Krafter på rörsystem vid transient flöde: En jämförelse mellan RELAP5 och Fluent2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    At Forsmarks Kraftgrupp AB (FKA) forces on pipe systems due to transient flow are frequently calculated as a step to verify their structural integrity. In nuclear industries these forces are often calculated with a one dimensional thermal-hydraulic analysis-code called RELAP5. When calculations regarding more complex geometries are needed, the three dimensional code Fluent is often used. This code is highly time consuming and requires large computational power.

    This projects aim is to compare calculations of pressure, flow and forces carried out by RELAP5 and Fluent for an arbitrary pipe section during transient flow conditions. This has been accomplished by constructing a simple geometry for which a transient flow is simulated in both programs. Forces have been calculated via pressure difference over the pipe section and also by use of differentiated mass flow. In Fluent k-ω SST and VLES turbulence models have been used and also two different numerical schemes in order to investigate their influence on the results.

    The results show that forces calculated with RELAP5 and Fluent are in parity. Small differences in mass flow and pressure appear when comparing between the codes. This probably stem from different handling of losses in RELAP5 and Fluent. The differences have no effect on forces calculated since the differentiated mass flow and pressure difference used are equivalent for both codes. 

  • 275.
    Kayumba, Epimaque
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Design of a Battery Charging System Using a Micro-Hydro Power for Rwandan Rural Area Electrification2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 276.
    Kekonius, Henrik
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Martinsson, Gustaf
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Framgångsfaktorer för arbete med funktionsöverskridande processer: En fallstudie vid Ericsson AB2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    A product often consists for the most part of purchased materials and to reduce the total cost of production, therefore, companies often focus on reducing their purchase prices. Pushing supplier prices in this way is a popular way to improve the company's short-term profits.

    Ericsson negotiates annually with its suppliers to reduce their purchase prices, which is considered to reduce purchasing costs and thus the production costs. This is achieved by the sourcing function in a process known as the VPA process. The VPA process requires information from the local supply functions, which, however, has no documented approach for these activities. The purpose of this study is, therefore, to create a support processes to sourcing VPA process. We have also from a theoretical approach critically reviewed the existing process.

    What we found is that Ericsson's approach could be sub optimized, focusing on achieving internal goals within the function creates obstacles for other functions. Often, if not always, each function focuses on its own goals and do not have a holistic view on organizational performance. This means that the organization as a whole may suffer when instead of optimizing process output, local optimization leads to total sub optimization.

    To prevent sub optimization, functions needs to create an understanding of the other functions goals, communication between the functions are therefore of critical nature. However, this is not enough, to reduce the focus on goals within functions and instead focus on process goals requires that senior management will create this opportunity.

  • 277.
    Khosravi Bakhtiari, Hossein
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Construction, Gavlefastigheter Company, Gävle, Sweden.
    Akander, Jan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Evaluation of Thermal Comfort in a Historic Building Refurbished to an Office Building with Modernized HVAC Systems2019Inngår i: Advances in Building Energy Research, ISSN 1751-2549, E-ISSN 1756-2201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Envelopes with low thermal performance are common characteristics in European historic buildings, causing higher energy demand and insufficient thermal comfort. This paper presents the results of a study on indoor environmental quality (IEQ), with special focus on thermal comfort, in the historic City Hall of Gävle, Sweden, now used as an office building. There are two modern heat recovery ventilation systems with displacement ventilation supply devices. The district heating network heats the building via pre-heat supply air and radiators. Summer cooling comes from electric heat pump ejecting heat into the exhaust ventilation air. A building management system (BMS) controls the heating, ventilation and air-conditioning (HVAC) equipment. The methodology included on-site measurements, BMS data logging and evaluating the occupants’ perception of a summer and a winter period indoor environment using a standardized questionnaire. In conclusion, indoor environmental quality in this historic building is unsatisfactory. Stuffy air, too high, too low and varying room temperatures, lighting problems and noise are constant issues. Although it is equipped with modern ventilation systems, there are still possibilities for improving thermal comfort by improved control strategies, since upgrading the building’s envelope is not allowed according to the Swedish Building Regulations in historic buildings with heritage value.

  • 278.
    Kobayashi, T
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Sakara, K
    Yamanaka, T
    Kotani, H
    Sandberg, Mats
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Wind driven flow through openings: analysis of the stream tube2006Inngår i: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 4, nr 4, s. 323-336Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wind approaching a building provided with openings on the windward and leeward sides has a choice, either it flows through the openings or flows around and above the building. This choice gives rise to a dominant stream tube containing the fluid flowing through the openings. In this paper the stream tube is analysed based on wind tunnel measurements and CFD simulation. A house model with dimensions 120 mm (Width)×120 mm (Height)×180 mm (Length) was provided with rectangular openings of equal size located opposite each other. The end walls were thin giving rise to a sharp edged opening. The size of the openings expressed as the porosity (opening area divided by the façade area) was 1.3 %, 5.2 %, 11.6 %, 20.7 % and 46.5 %. In the wind tunnel, velocity including velocity fluctuations and pressure were measured along the centre line through the openings. In the CFD prediction it was possible to visualize the stream tube by the method of “flying particles”. This made it possible to explore the change in shape of the stream tube and to calculate the cross-sections of the stream tube at different positions and to know the total pressure distribution within the stream tube cross section. Finally, the discharge coefficient based on stream tube analysis was compared to that from a conventional chamber method.

  • 279.
    Kobayashi, Tomo
    et al.
    Department of Architectural Engineering, Osaka University, Division of Global Architecture, Osaka, Japan.
    Sagara, Kazunobu
    Department of Architectural Engineering, Osaka University, Division of Global Architecture, Osaka, Japan.
    Yamanaka, Toshio
    Department of Architectural Engineering, Osaka University, Division of Global Architecture, Osaka, Japan.
    Kotani, Hisahi
    Department of Architectural Engineering, Osaka University, Division of Global Architecture, Osaka, Japan.
    Sandberg, Mats
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Power transportation inside stream tube of cross-ventilated simple shaped model and pitched roof house2009Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 44, nr 7, s. 1440-1451Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ultimate goal of this work is to establish a prediction method based on Power Balance Model for prediction of flow rate through cross-ventilated building. For the establishment of Power Balance Model, the lost power across stream tube sections must be determined in advance. However, the loss of power in the stream tube was not well studied by other researchers but this concerned critical step forms the focus of the present CFD study in which transported power in stream tubes formed at two selected models: (i) a suspended rectangular model, and (ii) a pitched roof single-storey house model standing on a flat ground surface, was documented. For the development of a new method applying to predict the lost power, decrease of the transported power across the stream tubes through both types of models will finally be shown in this paper.

  • 280.
    Kobayashi, Tomohiro
    et al.
    Department of Architecture, School of Engineering, Osaka City University, Japan.
    Sugita, Kazuki
    Department of Architecture, School of Engineering, Osaka City University, Japan.
    Umemiya, Noriko
    Department of Architecture, School of Engineering, Osaka City University, Japan.
    Kishimoto, Takashi
    Kyoto Institute, Kinden Corporation, Japan.
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Numerical investigation and accuracy verification of indoor environment for an impinging jet ventilated room using computational fluid dynamics2017Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 115, s. 251-268Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The impinging jet ventilation (IJV) system has been proposed as an air distribution strategy to provide a better thermal environment with a medium supply momentum than displacement ventilation (DV) system. However, no simplified prediction method that is practically applicable has been established to date. The ultimate goal of this study is to establish a calculation model to predict the vertical temperature profile in an IJV system. The authors aim to propose a one-dimensional model, where the room is divided into several control volumes. To perform this, the turbulent thermal diffusion between control volumes needs to be well understood. Therefore, a knowledge about the effect of each design factor such as the supply air velocity on the turbulent thermal diffusivity needs to be acquired through a parametric study. Computational Fluid Dynamics (CFD) is effective for this purpose. As a first step, the accuracy of CFD simulations is verified by conducting a full-scale experiment. The velocity profiles inside the impinging jet and the indoor temperatures are measured and compared with the CFD results. It is shown that the shear-stress transport k-ω model has a sufficient accuracy to analyse the target room, and an appropriate grid layout is established as well. The convection-radiation coupling CFD prediction where the external temperature is used as a boundary condition is adopted as the best method for the numerical study in this research. Finally, a parametric study on the supply air velocity is performed based on this setting and its effect on the thermal stratification is presented. 

  • 281.
    Kovac, Senad
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Holmgren, Mikael
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Analysis of internal communication: case study Sandvik SMT Market Service2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Large scale companies have massive information flows in their administrative

    departments. This often creates problems when there is a lack of communication both

    internally and with internal partners such as sales units.

    Sandvik SMT Market Service (SBMS) is no exception in this case. They got big

    problems with their communication with the sales units especially when it concerns the

    mail traffic and routing of information. Today SBMS have three regional mailboxes

    where the SU’s (Sales Unit) send their mails depending on which region they belong to.

    This structure does not function as intended and creates an overload which leads to long

    response times.

    Therefore the market service manager Jonas Hofvenstam wanted us to investigate this

    problem area with the possibility of segmenting the mailboxes including a tagging system

    and to perform a review of the sales tools portal in order to shorten the response times

    and decrease the mail traffic.

    The outcome of this paper was suggestions/proposals regarding how to structure the

    common mailboxes, illustration of a tagging system for the mails and suggestions of how

    to improve the sales tools portal. We also made recommendations on how to take these

    suggestions into action including step by step instructions to make it easier when

    performing an implementation.

  • 282.
    KUBWIMANA, Valens
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Evaluating sustainability of electricity access in Rwanda (2009 to 2013)2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sustainable energy supplies have been a key to economic development and the transition from agricultural economies to modern industrial and service-oriented societies. Energy as essential to improved social and economic welfare is a key for reducing poverty and raising living standards. However, still 1.2 billion people have no access to electricity [1] and providing sustainable energy access to these people is a real challenge. How Rwanda is performing in terms of providing sustainable electricity to its rural people? This thesis evaluates the relative performance of Rwanda from 2009 to 2013 in providing sustainable electricity access. The evaluation of sustainability of electricity access situation was undertaken using Principal Components Analysis technique (PCA) whereby a theoretical framework defining sustainability of electricity was constructed and a set of indicators has been selected basing on analytical soundness, measurability and ability to describe electricity sustainability phenomenon and also basing on the availability of data to define and determine the sustainability. The study shows that the sustainability for electricity access in Rwanda has been improved for the evaluated period of time (2009-2013). The results conclude that the sustainability of electricity access situation has gone up and this is due to the introduction of many programs that have been instigated and Government commitment to improve the electrification rate. Some strategies, commitments and laws such as electricity law, National energy policy and national energy strategic plan; economic development and Poverty Reduction Strategy as well as Renewable Energy Feed In –Tariffs and electricity access roll-out program that were executed in these period seems to be instrumental in achieving better performance in terms of electricity sustainability.

  • 283.
    Kumara, Thanura Padma
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Analysis of floating type water wheel for pico hydro systems in Sri Lanka 2014Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sri Lanka is an island in the Indian Ocean and water is freely available around the island. Most of the people from rural areas are farmers and they cultivate in large areas. But they do not have electricity for pumping water to their agricultural. Normally channels are used to convey water into land but most of the time agricultural lands are situated at higher positions than the channels which make it difficult to transport water. The kinematic energy of water flow in those channels could be converted into useful energy, which in turn could be used for pumping water to higher elevations. For this purpose a simple method such as water wheel could be easily employed to generate electricity.

    This study mainly focused on to carry out a feasible study based on the existing details of water wheel with related accessories and improves the overall working efficiency while developing a new system or modification of the present system and transfer the technology to the rural community.

    A theoretical analysis of the water wheel was done based on 6 blades straight type wheel. The performance testing of water wheels in open channel were carry out for three types of blades and two different numbers of blades( 6 and 12).Based on the results It shows that 5% deviation between theoretical and experimental values of power and 36% deviation between theoretical and experimental values of R.P.M.

    Also results obtained by testing of water wheels showed that experimental results of 12 blades water wheels were more powerful compared with 6 blades water wheels. It is approximately 2.5-3 times factor.

    Based on this results calculations were carried out for 6 blade water wheel and predictions were done for a twelve wheel inclined blade wheel type considering the factors that affect the performance of the wheel. According to the test results, the average power output of the 12 blade curved type water wheel was 9.5 W. Solid works software was used to carry out the simulation to determine the stability and properties of blade.

    According to analysis, floating type water wheel was found to be economical for rural areas because the cost of building a plant is US$ 340 and it is cheaper than other methods.

  • 284. Kärrman, Erik
    et al.
    Sörelius, Helene
    Eriksson, Ola
    Tegelberg, Linda
    Hantering av slam och organiska restprodukter i Gästrikeregionen: Förstudie2013Rapport (Annet vitenskapelig)
  • 285.
    Lajas, Sandra
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Viability of the electricity production comparing photovoltaic and wind power in three markets.2012Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    To carry out the implementation of some type of renewable energy must do a viability study because the weather conditions at all sites are not the same and therefore the profitability of these technologies would not be good.

    In case of this project, it is taken into account two of the most important technologies which results are very good around of the world. They are photovoltaic and wind power energy.

    It will be analysed both kind of energy production from how to produce energy with photovoltaic system and with wind power till how much energy is produced by both ways in one year and whether is this ways to produce electricity is profitable in relation of the investment costs, maintenance, etc...

  • 286.
    Lakemond, Nicolette
    et al.
    Linköpings universitet.
    Bengtsson, Lars
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Industriell ekonomi. Högskolan i Gävle, Centrum för logistik och innovativ produktion.
    Laursen, Keld
    Copenhagen Business School.
    Tell, Fredrik
    Uppsala universitet.
    Knowledge integration across boundaries in open innovation2015Konferansepaper (Fagfellevurdert)
  • 287.
    Lane, Anna-Lena
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. RISE Research Institutes of Sweden.
    Boork, Magdalena
    RISE Research Institutes of Sweden.
    Thollander, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Barriers, driving forces and non-energy benefits for battery storage in photovoltaic (PV) systems in modern agriculture2019Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 18, artikkel-id 3568Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Battery storage has been highlighted as one way to increase the share of renewables in energy systems. The use of local battery storage is also beneficial when reducing power variations in the grid, thereby contributing to more robust and cost-effective energy systems. The purpose of this paper is to investigate barriers, drivers and non-energy benefits (NEB) for investments in battery storage in photovoltaic systems (PV) in the context of farmers with PV systems in Sweden. The study is based on a questionnaire about barriers, driving forces and NEB for investment in battery storage connected to PV. The questionnaire was sent to farmers in Sweden who already have photovoltaics installed and about 100 persons answered, a response rate of 59%. The major barriers found are related to the technical and economic risks of investing in battery storage. One of the main conclusions is that the highest-ranked driver, i.e., to use a larger part of the produced electricity oneself, turns out to be the highest priority for the grid-owner seeking to reduce the need for extensive investments in the grid. The primary NEBs found were the possibility of becoming independent from grid electricity.

  • 288.
    Lane, Anna-Lena
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. SP Technical Research Institute of Sweden.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Gustavsson, Thorbjörn
    SP Technical Research Institute of Sweden.
    ByggaE – Method for Quality Assurance of Energy Efficient Buildings2017Inngår i: International Journal of Energy Production and Management, ISSN 2056-3272, E-ISSN 2056-3280, Vol. 2, nr 2, s. 133-139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Policies for energy efficiency requirements in buildings have become more stringent according to EU2020 goals. Despite policy regulations, requirements for energy efficiency are not met in many new buildings. Some of the reasons for this energy performance gap are related to the building process. The aim with this paper is to describe a purposed method for quality assurance of sustainable buildings according to energy efficiency. The proposed method is called ByggaE, where ‘Bygga’ is the Swedish word for ‘build’ and E is the first letter in ‘energy efficient’. It is a tool intended to lower the energy performance gap related to the building process by guiding the client and providers through the process to fulfill goals. The essence of ByggaE is the formulation of requirements by the client and the working process of identifying, handling and following up critical constructions and key issues. This working process involves all participants in the building project by using appropriate quality guidelines and checklists for documentation, communication and verification. ByggaE is a step forward ensuring that the building fulfills the defined functions and that conscious decisions are taken when goals have to be changed during the building project. The next steps are to ensure the usefulness of the method in practice by more testing and to spread knowledge about the method.

  • 289.
    Larsson, Erik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Småskalig kraftvärmeproduktion för ett medelstort svenskt industriföretag: Potentialen för konventionell Rankinecykel2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Utsläppen av växthusgaser måste minska snabbt under de kommande åren. Sveriges mål är att uppnå nettonollutsläpp till år 2045. Industrisektorn spelar en avgörande roll i omställningsarbetet genom att minska sitt energibehov och fasa ut sin användning av fossila bränslen, teknikutvecklingen måste gå mot mer klimatsmarta och hållbara produkter och produktionsmetoder. Omställningen kommer att kräva ett mer robust och tillförlitligt energisystem där dagens centraliserade system kompletteras med mindre decentraliserade produktionsanläggningar så att effekt- och energibehov kan tillgodoses i alla lägen. Att producera el och värme närmare användaren bidrar till minskade överföringsförluster. Småskalig kraftvärmeproduktion (CHP) baserad på biobränslen eller restvärmeresurser kan vara en del av lösningen för att minska utsläppen av växthusgaser.

    Syftet med det här examensarbetet är att undersöka möjligheten för ett medelstort svenskt industriföretag att producera sitt eget basbehov av värme och el med hjälp av den konventionella Rankinecykeln. Samt att undersöka hur produktionskostnaderna av el och värme förändras beroende på anläggningens storlek.

    Arbetet har bestått av datainsamling från olika tillverkare av turbiner och pannor, en beräkningsmodell skapades i Excel där anläggningar av olika storlek har jämförts vid olika driftscenarion. Ekonomiska kalkyler har gjorts med hjälp av Pay-off metoden och Nuvärdesmetoden.

    Resultatet visar att produktionskostnaderna för anläggningar med turbiner i storleksordningen 10 – 100 kWel ligger på en relativt jämn nivå och betydligt lägre än priserna på köpt el och fjärrvärme. Den ekonomiska bedömningen visar generellt på positiva resultat med korta pay-offtider och positiva nuvärden.

    En jämförelse av anläggningarna visar att elverkningsgraden är låg och att totalverkningsgraden i vissa fall blir lägre än för företagets befintliga värmeleverantör. Detta visar att trots att det ur ett ekonomiskt perspektiv kan vara en lönsam investering kan det ur ett systemperspektiv vara ett sämre alternativ då en lägre verkningsgrad leder till en ökad primärenergianvändning.

    Det är många parametrar som påverkar en CHP-anläggnings prestanda och ekonomiska lönsamhet, men en av de viktigaste är drifttiden. Att ha en kontinuerlig drift under större delen av året har stor påverkan på anläggningens ekonomiska prestanda. Anläggningens låga elverkningsgrad gör också att största besparingen hamnar på värmeproduktionen vilket gör att anläggningen bör dimensioneras så att den ersätter så stor del som möjligt av företagets värmebehov.

  • 290.
    Larsson, Henrik
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Eldblom, Lars
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Utveckling av blästeranläggning för bladfjädrar: till Trainparts SWeden AB i Bollnäs2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Abrasive blasting is a large field and a process that has long existed in mechanical manufacturing. The unpredictable nature of the process makes its research in most cases not theoretically calculated. Instead experiments are used to verify various parameters in the design. In this work, no detailed experiments could be performed due. to time and resource constraints. Trainparts Sweden AB in Bollnäs reconditions and manufactures leaf springs for rail vehicles, and they want to investigate the introduction of abrasive blasting in their production line. The aim is to investigate what kind of abrasive blasting equipment that fit the company's production line. The goal is to develop a concept proposal on a abrasive blasting machine for own manufacturing or facilitating an investment of a market existing machine.

     

    To come up with a concept proposal a simple working model were developed and was followed during the work on the thesis. Market research on existing abrasive blasting machines and literature studies in the affected areas was conducted as the basis for the work. Thereafter a comparison with respect to cost, efficiency and application of the different parameters in the abrasive blasting process was made.

     

    The result of this work is a wheel blasting machine with four wheels; this is what gives the best results for the products.

     

    Our conclusion is that a wheel blasting machine is the best option from a manufacturing standpoint but because of high purchase price and low production volumes, it may be appropriate to look at other approaches.

  • 291.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Attraktivitet är en färskvara2009Inngår i: Dagens juridik, nr 2 febArtikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 292.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik, fysik och matematik.
    Chefen kan vara en friskfaktor2005Inngår i: Hälsa i staten, Vol. 3, s. 11-Artikkel i tidsskrift (Annet vitenskapelig)
  • 293.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    CSR - papperstiger eller riktig tiger?2009Inngår i: CSR i praktiken, nr 2 AprArtikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 294.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    En attraktiv arbetsplats - en uthållig konkurrensfaktor2008Inngår i: Dagens Juridik, nr 18 FebArtikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 295.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    En hälsofrämjande verksamhetsstyrning2008Inngår i: Dagens Juridik, nr 31 OktArtikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 296.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    En systematisk metod för att skapa attraktiva arbetsplatser2009Inngår i: Dagens Juridik, nr 9 MarArtikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 297.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Healthy and Effective Leadership in Organisations2010 (oppl. 1)Bok (Annet vitenskapelig)
  • 298.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik, fysik och matematik.
    Hälsofrämjande verksamhetsstyrning - från statistik till strategi2007Inngår i: Kundorienterat : Nyhetsbrev från institutet för kvalitetsutveckling, ISSN 0284-9305, nr 1Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 299.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Leadership for Quality, Effectiveness and Health in Organisations2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Leadership, quality, effectiveness and health are important factors in the achievement of organisational success. Three questions are addressed to study these elements:

    1. How do leadership values relate to leadership behaviours, quality methodologies and health in organisations?

    2. How do leadership behaviours relate to effectiveness and health in organisations?

    3. How can leadership tools be designed and used to promote health in organisations?

    The research is based on five studies from three research projects. This research is reported in five papers. Study I concerned eight organisations in the middle of Sweden; the focus was on leadership values and behaviours. Study II concerned three successful organisations that received the award, ‘Sweden’s number one workplace’. Focus in this study was mainly on leadership behaviours. Study III combined results from Studies I and II with a focus on successful leadership behaviours. Study IV concerned the eight organisations in Study I. A leadership tool in the form of a Plan-Do-Study-Act (PDSA) model was developed and evaluated. Study V was of two organisations in Sweden; the focus in that work was on the use of a leadership tool control chart designed to give managers statistically valid early warning signals about health in their organisations. Theory X and Y together with the three-dimensional leadership behaviour theory were used to assess leadership values and behaviours. The theory surrounding PDSA and control charts were used to develop leadership tools. The dimension of health is defined from a salutogenic humanistic perspective; which emphasizes individual well-being. The dimension of quality is defined as the ability to satisfy or exceed needs and expectations. Effectiveness is defined as the extent to which externally and internally defined objectives are fulfilled.

    Both qualitative and quantitative research methods were used. Interviews, seminars with employees, collection of human resource and effectiveness figures, and questionnaires completed by managers and subordinates were used to collect data.

    Managers with more Theory Y-oriented leadership values were rated by subordinates as high concerning quality methodologies and leadership behaviour dimensions. The subordinates of these managers tended to be healthier.

    Two of the studies identified common groups of leadership behaviours in effective and healthy organisations: strategy and vision, communication and information, authority and responsibility, learning culture, worker conversations, plainness and simplicity, humanity and trust, walking around and reflective personal leadership.

    These leadership behaviours fit into a leadership profile where all three of the dimensions of structure, relation and change are present. Of the three, the relation dimension is strongest and concluded to be a universal dimension.

    The developed PDSA model seems to be a leadership tool that influences both leadership values and behaviour, particularly in the area of relation-oriented leadership behaviours. An early warning system built on CUSUM- and Shewhartcharts concerning the health indicators of self-assessed general health and new sickcases per employee was also found to be a powerful and usable leadership tool.

    For future research, the explorative research findings can be quantitatively tested using representative and preferably cross-national data, with a longitudinal design.

  • 300.
    Larsson, Johan
    Mittuniversitetet, Institutionen för teknik, fysik och matematik.
    Ledarskap för hälsa och lönsamhet2005Inngår i: Kvalitetsmagasinet : tidningen för kvalitets- och verksamhetsutveckling, ISSN 1104-1579, s. 22-24Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Hur kan ledare arbeta för att stödja utvecklingen för en hållbar hälsa hos alla medarbetare i organisationen? Delegering av ansvar och befogenheter, insikten att alla människor är olika samt målet att ha kul på jobbet är några faktorer som bidragit till ett framgångsrikt ledarskap på Roxtec International.

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