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  • 151.
    Pathirathna, Kuruppulage Asela Buddhika
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Gas Turbine Thermodynamic and Performance Analysis Methods Using Available Catalog Data2013Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The overall performance of an open gas turbine can be judged with the knowledge of the main design parameters, but this is quite challenging due to the limited data available from the manufacturer. The turbine manufacturers usually provide data about the turbine interface. However, the data (or information) required to analyze the thermodynamic quality of the gas turbine remains hidden. A theoretical model was developed to evaluate the thermodynamic performance of an open gas turbine (with one combustor) by using available catalog data. Realistic values (from experience) were assumed for the compressor polytropic efficiency, mechanical efficiency, electrical efficiency and pressure drops of the gas turbine. The Engineering Equation Solver (EES) tool has been used for implementing the theoretical model. The published catalog data from the manufacturers is kept as main inputs for the modeled program. The model calculates (or predicts) values for the unknowns i.e. temperature, isentropic and polytropic efficiencies of the individual components (inside the gas turbine), power output and some emission related parameters. The developed program is aimed to be used in the learning lab at the KTH energy department while being a part of the CompEdu learning platform. This program should provide students a possibility to fully analyze the performance of the open gas turbine cycle while judging consistency of gas turbine cycle data sets and completing incomplete gas turbine datasets.

  • 152.
    Peiris, Ambagaha Pathirage Thanushka Sandaruwan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Feasibility Study of Production of Bio Methane from Bio Wastes in Sri Lanka and Develop Cost Model for the Production Process2016Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Generation of wastes as a result of expanding economic activities and change life styles of people is on the increase from recent times in Sri Lanka, especially in urban areas. The government authorities, both national and provincial, have no firm plans to manage the generation of wastes as well as safe disposal of unavoidable wastes. The wastes composition of the country is fortunately rich of biodegradable substances and it is a good indication that these wastes could be utilized in anaerobic digestion systems for the generation of biogas. Sri Lanka has over four decade’s history of using anaerobic digestion (AD) with a little expansion to deal the situation of high level of wastes being accumulated in most of the cities. Further, AD technology is not developed to the same scale as of the western countries due to various reasons related to technological know-how, economic, social and cultural practices together with misconceptions with regard to the economic benefits that could be derived from AD. This research work mainly focused on two objectives, namely to evaluate the feasibility of production of biomethane under Sri Lankan context and to develop a cost model for the production process, i.e. investor decision tool for the biomethane projects. During the study, it was considered that the overall process from input feedstock to a biogas plant to produce cleaned and upgraded biogas (biomethane), has over 95% of CH 4 . It was also considered two main end products based on purified biogas (biomethane) such as bottled biomethane and generation of electricity from combustion of biomethane on a generator coupled to an internal combustion engine or a gas turbine. Revenues of the project are made by said one product or both products. There were number of algorithms or logics made for quantifying capital cost (CAPEX) and operational expenses (OPEX) of a considered project. After estimating the revenue of such a project, net present value, internal rate of return and simple payback period for own investment were calculated (a calculation guide for those indicators provided). Those indicators are used as guides to select a successful project. It was important that co-digestion of various substrates (mainly municipal solid wastes) were considered during the development of a model.

  • 153.
    Pekkala, Ossian
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Integrated heat exchanger for shower cabins: Legal issues, cost efficiency, designing a prototype2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The global energy usage have been growing and is expected to grow in the forthcoming years. The negative effects of increased energy use are greatly depending on the type of base raw materials required for converting the energy and the negative consequences those have on the environment. From the energy used, fossil fuels stands for the largest part. Excess use of fossil fuels have been shown to have considerable negative effects on the environment, including, but not limited to global warming.

    Renewable energy is today the world’s fastest growing energy source limiting the negative consequences of growing energy use. The commercial and residential buildings stands together for about 40 % of the total energy usage.

    Residential buildings alone stands for 20 % of the total world delivered energy consumption by end-use sector. In EU the average residential energy use amounts to 25 % and for individual countries like Sweden and Finland it is 21 %.

    The EU energy efficiency directive from year 2012 sets a target to save 20 % of the unions primary energy usage by year 2020 compared to the year 1990. The EU countries also agreed in October 2014 on a new energy efficiency target of at least 27 % by the year 2030. To reach this goal, improved energy efficiency are required in all sectors.

    Finland’s energy efficiency law for buildings from 2013 greatly reduces the minimum energy usage allowed for new buildings. Finland is also preparing for a new law that would by 2020 require all new buildings to be zero or close to zero energy buildings. This is defined by the Ministry of the Environment as buildings that have very high energy efficiency, where the already greatly reduced energy demand is satisfied extensively by renewable energy.

    As part of the goal to greatly increase buildings energy efficiency, this work focus on heat exchangers for showers. The purpose of this project is to investigate how two different heat exchangers works for shower cabins. This is done by testing a system where the heat exchangers are linked together. The system works by transferring heat from the drainage water and the moist air to the incoming colder drinking water before the cold water is heated in the mixerto desired shower temperature. The measurements are taken for different simulated shower situations. The Heat exchangers efficiency are calculated and the energy savings are examined with annual energy savings. The payback time shows that the system is not currently viable. The efficiency need to be improved, the main issue being the constituent materials heat transfer attributes between cold and hot water. The results are discussed and it is concluded that the system would be viable with improved heat exchanger efficiency and adequate shower use, which depends on the user and the amount of people using the shower. The main issue with increased heat transfer efficiency is the greater risk of contamination between the incoming cold drinking water and the outgoing dirty drainage water.

  • 154.
    Perera, Sam Prasanna Kurukulasuriya
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Kachchakaduge, Sumith Ruwan Dharmasiri
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    SMART VAR Generator to Manage Grid Voltage Stability issue of Low Frequency Switching Photovoltaic Inverters2015Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Solar power, clean and abundant, is considered as a vital contributor in the effort of transforming world energy-mix to pollution-free and natural-regenerative sources.   The solar micro inverters have gained greater visibility during the past several years due to their higher efficiency, greater performances, longer life expectancy and many other benefits. But, integrating small scale [<15kW] renewable energy sources, especially the low frequency switching solar inverters to the low voltage distribution grid has its own challenges due to their inability to generate reactive power to maintain the static voltage stability of the grid.

    Higher level of solar penetration has identified as a potential cause of low voltage grid instability due to lack of reactive power feeding and their tendency to keep on increasing the voltage higher than grid at the point of common connection [PCC] in order to inject the current to the grid. The studies and experience in voltage stability issues has resulted in introducing many new grid regulations to manage the grid voltage stability throughout the world.

    The new regulation, VDE-AR-N-4105-2011 is a German grid regulation standard specifically focuses on the low voltage grid connected power generators. This regulation has addressed the reactive power requirements in terms of power factor and supply management to maintain the grid static voltage variation less than 3% at the PCC, when connecting any type of distributed power generators to the low voltage network.

    This report discuss about the voltage stability issues related to low frequency switching inverters and present a solution to comply with low voltage grid regulation - VDE-AR-N-4105-2011; a SmartVar Generator concept, theory, design and functionality.

  • 155. Persson, Tobias
    et al.
    Blom, Angelika
    Schnürer, Anna
    Atterwall, Annika
    Hellström, Daniel
    Kreuger, Emma
    Jönsson, Hanna
    Sárvári Horváth, Ilona
    Lantz, Mikael
    Eriksson, Ola
    Mårtensson, Per
    Hebrand, Sofie
    Söderström, Yvonne
    Davidsson, Åsa
    Nordberg, Åke
    Sammanställning av svensk forskning och utveckling inom biogasområdet under 20132014Report (Other academic)
  • 156.
    Rafart, Jordi
    University of Gävle, Department of Technology and Built Environment.
    Improving of the heat transfer from a moulding block in an industrial oven2008Student paper second term, 20 points / 30 hpStudent thesis
    Abstract [en]

    This thesis presents a study of the cooling process of a solid block performed by a turbulent air flow channel. The study focuses on the turbulent flow and its influence in the heat transfer of the block.

    The first part of the thesis is an analysis of the different turbulent model and their adaptation on the necessities of this study. Once the turbulent model has been confirmed it makes a study of the behavior of the cooling process by CFD (Computational Fluid Dynamics), and an analysis of the numerical accuracy of this computational study.

    When the procedure of the study of the cooling process is defined it proposes some different variations in the initial solution to improve this process. The study concentrates in variations of the turbulence and the geometry of the studied block.

    Finally, the different improving are discussed analyzing parameters as the heat transfer, pressure drop, time consuming or energy consuming.

  • 157.
    Ragulis, Paulius
    et al.
    Microwave Laboratory of Center for Physical Sciences andTechnology, Vilnius, Lithuania.
    Ängskog, Per
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Simniškis, Rimantas
    Microwave Laboratory of Center for Physical Sciences andTechnology, Vilnius, Lithuania.
    Vallhagen, Bengt
    Saab Aeronautics, Linköping, Sweden.
    Bäckström, Mats
    Saab Aeronautics, Linköping, Sweden.
    Kancleris, Žilvinas
    Shielding Effectiveness of Modern Energy-Saving Glasses and Windows2017In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 65, no 8, p. 4250-4258Article in journal (Refereed)
    Abstract [en]

    Thin metal coatings on glass are widely used in modern windows to improve their thermal properties. However, while there are some available papers on the properties of microwave propagation through commercial metallized windows glass below 6 GHz there seems to be a lack of papers regarding metallized multi-glazed windows at higher frequencies. Such data are of the great importance when designing modern microwave communication systems working in urban environments. In this paper, the shielding effectiveness of modern energy-saving glasses and windows were investigated at microwave frequencies from 1 GHz to 20 GHz. Wide measurement range together with proposed fast calculation procedure based on the matrix multiplication method, allowed us to elucidate the reasons responsible for the extremes in dependencies of shielding effectiveness on frequency. It was also shown that by comparing measured and calculated results, the conductivity of the thin metallic layer used in modern energy-saving windows can be determined. During the study, we found that attenuation of microwave radiation passing through modern windows can be as high as 60 dB.

  • 158.
    Rajapakshe, Chinthana
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. Royal Institute of Technology.
    HEAT STORAGE APPLICATION IN ELECTRIC MOTOR COOLING SYSTEM: SMOKE VENTILATION MOTORS2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 159.
    Rask, Kristoffer
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Värmeåtervinning ur spillvatten: En utredning av möjligheterna med spillvattenvärmeväxlare2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report is to investigate the possibilities with drain water heat recovery (DWHR) in residential buildings. Information and relevant theory has been collected and summarized in this report. Calculations have been done for given scenarios to evaluate profits. DWHR heat exchangers use simple technology and have long life-time. The heat exchanger is connected to outgoing drainage pipe and incoming cold-water supply so countercurrent flow is accomplished. This makes it possible to increase the temperature of the incoming cold-water and thereby decrease the amount of energy used to heat water. There are mainly two types of models on the markets, vertically and horizontally heat exchangers. DWHR can be cost-effective if installed during new constructions or renovation, otherwise installation costs can be quite expensive. An installation of a DWHR-unit means no increasing risks of bacteria growth (legionella). Approximately 20 % of the energy used to heat hot-water can be counted as internal heat gain, with a DWHR heat exchanger the amount increases which will result in less energy consumed in the room heating system. More development of existing models is required to reduce the prices and spread information. A big advantage with DWHR is that the energy need for heating water is quite constant during the whole year compared to other demands, for example room-heating. Results from calculations in this report show that a reduction of 43 % of the heating demand for hot-water could be made in a normal family house and 17 % reduction could be made in a residential building with fifty apartments.

  • 160.
    Rundström, Daniel
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Investigation of flow and heat transfer of an impinging jet in a cross-flow for cooling of a heated cube2006In: Journal of Electronic Packaging, ISSN 1043-7398, E-ISSN 1528-9044, Vol. 128, no 2, p. 150-156Article in journal (Refereed)
    Abstract [en]

    The current trends toward the greater functionality of electronic devices are resulting in a steady increase in the amount of heat dissipated from electronic components. Forced channel flow is frequently used to remove heat at the walls of the channel where a PCB with a few high heat dissipating components is located. The overall cooling strategy thus must not only match the overall power dissipation load, but also address the requirements of the "hot" components. In order to cool the thermal load with forced channel flow, excessive flow rates will be required. The objective of this study is to investigate if targeted cooling systems, i.e., an impinging jet in combination with a low velocity channel flow, can improve the thermal performance of the system. The steady-state three-dimensional (3-D) model is developed with the Reynolds-Stress-Model (RSM) as a turbulence model. The geometrical case is a channel with a heated cube in the middle of the base plate and two inlets, one horizontal channel flow, and one vertical impinging jet. The numerical model is validated against experimental data obtained from three well-known cases, two cases with an impinging jet on a flat heated plate, and one case with a heated cube in a single channel flow. The effects of the jet Re and jet to-cross-flow velocity ratio are investigated. The airflow pattern around the cube and the surface temperature of the cube as well as the mean values and local distributions of the heat transfer coefficient are presented.

  • 161.
    Sadik, Zidar
    University of Gävle, Department of Technology and Built Environment.
    Samkörning mellan värmepumpar och fjärrvärme: Bostadsrättsföreningen Bogården2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This diploma work covers an investigation over the heat - and hot water systems of the

    tenant-owner's association, Bogården. The heat - and hot water needs of Bogården are

    satisfied by both district heating as well as three heat pumps. Implemented investigation

    shows that the heat pumps are not used in a profitable way. Apart from that, the reserve

    possibilities are small. There is also a risk of the growth of Legionella bacterium in the

    hot water system.

    Since the heat pumps are already installed, HSB-Gävleborg (responsible for Bogården)

    has a wish to investigate possible proposed actions for optimization of existing plant.

    After completed investigation, a new proposed action is presented. The new proposed

    action goes on intercepting the hot water production and using the heat pumps to only

    heat production during the heating season. Why the hot water production should be

    intercepted, is just in order to eliminate the risk of Legionella. Besides, the new proposal

    is going to bring about a reserve of 1,534,000 SEK during a twenty-year period. This is

    approximately twice as much as what the existing plant may bring during the same

    period.

    During the work's review, it also has been established that heat - and hot water systems

    are error regulated. Since the diploma work does not cover that piece it is instead

    informed as proposals subject to further investigation.

  • 162.
    Saizar Zubeldia, Xabier
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Vila Montagut, Gerard
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Analysis of the Solarus C-PVT solar collector and design of a new prototype: Market review and Production process guideline2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Finding cleaner and sustainable energy resources is one of the most important concerns for the development of humanity. Solar energy is taking an essential role in this matter as the production cost of solar collectors is decreasing and more solar installations are being set up every year throughout the world. One way of reducing the cost of solar panels is by using concentrators that are cheaper than the costly photovoltaic cells and can increase their output. Solarus AB designed a Photovoltaic Thermal (PVT) hybrid collector that uses this principle and which is a variation of the Maximum Reflector Collector (MaReCo) design and is a Compound Parabolic Collector (CPC).

    This thesis has two main objectives. The first one is to design variations of the actual Solarus’ design and some alternative MaReCo designs and pure parabola designs. These designs include new solar cell cuts which are based on 4 busbar solar cells. In this way a future in-depth analysis may be carried out by comparing different receiver designs and collector boxes. The second goal is to investigate the current electrical and thermal performance of the collectors from Solarus AB which are installed in the Hus 45 of HiG. The appropriate data of the installation has been obtained using simulations and specific software, and it has been analysed with Microsoft Excel®.

    Concerning the new designs of the receivers and boxes, everything has been prepared for the future construction of the prototypes. All the measurements and their adjustments have been taken into account to define the size of the components and the process of building has been set up. Moreover, some future work has been planned in order to move forward the project.

    Regarding the analysis of the HiG installation, both electrical and thermal performance have resulted to be significantly lower compared with their estimated simulation, being their real output around 60 % of the estimated one. In the thermal part, the losses in the pipeline result to be more than a third part of the produced heat. In the electrical part, the production varies a lot between different collectors due to some of them do not work properly, consequence of poor condition of the solar panels (broken cells, dirt, shading, etc.).

  • 163.
    Salehi, Farshid
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    The Study and Practical Application of Sustainable and Energy Efficient Design and Technology for HVAC and Centralised Solar Hot Water Systems in the Al Zeina Development, Abu Dhabi, United Arab Emirates2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 164.
    Sanchez, Javier
    University of Gävle, Department of Technology and Built Environment.
    Analysis of a new district heating line: Evaluation of heat losses and hydraulic facilities2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The aim of the project is to analyze the enlargement of the district heating line located in Gävle, evaluating the hydraulic facilities and calculating the heat losses with different insulation thicknesses to choose the best insulation thickness for the pipes. To choose the best thickness, different insulation thicknesses have been evaluated calculating the heat losses for each insulation thickness. To manage the heat losses problem, the pipe length has been divided into three

    stretches, underground pipe, sea pipe and air pipe. These three stretches have different boundary conditions, and each stretch has been calculated separately. The best thermal solution is choosing the insulation of 0.5m of thickness, but the best thermal solution is not the best solution for this project due to the elevated cost of this thickness in one of the stretches of the line. The pipe crossing the seahas to be on the bottom and to keep the pipe on the bottom concrete is going to be added. The quantity of concrete needed depends on the floatability of the pipe and specifically depends on the insulation thickness. The insulation is a porous material and its density is very small, therefore it has a high floatability. The final

    selection is a multi-thickness insulation, with different insulation thicknesses in the different stretches, 0.6m of thickness in the underground and air pipe and 0.3m of thickness in the sea pipe. With this configuration the heat losses are quite close to the optimum case. The purpose in the hydraulic study has been quantifying the start pressure in the new line to fulfil the energy demand in the worst point of the line. With 320kPa at the start of line, the pressure in the worst point is enough to fulfil the nowadays

    demand, 3MW, and in the future when this line will be enlarged and the demand increased to 20MW, the pressure at the start of the line to ensure the requested pressure of 250kPa in the worst point should reach more than 380kPa. Having such pressure is not recommended to avoid the pressure hammer and to build a new pumping station after the sea pipe is recommended.

  • 165.
    Sandén, Björn A.
    et al.
    Göteborgs miljövetenskapliga centrum (GMV) ; Institutionen för energi och miljö, Miljösystemanalys.
    Jonasson, Karl
    Göteborgs miljövetenskapliga centrum (GMV) ; Institutionen för energi och miljö, Miljösystemanalys.
    Competition and co-evolution among contenders: The development of alternative transport fuels in Sweden 1974-20042005In: 4th European Meeting on Applied Evolutionary Economics (EMAEE), 2005Conference paper (Other academic)
    Abstract [en]

    Building on previous research, we further develop a theoretical framework for transition analysis. In particular, we are interested in the forces that guide the direction of change. We differentiate between exogenous and endogenous change where the latter can be described by the cumulative build-up of stocks and structures, which create path dependence, within a socio-technical system. Using this theoretical framework we discuss the relationship between different emerging technological alternatives to an incumbent technology, their competition and co-evolution, and their roles as bridges and dead-ends in a transition process. We then describe and analyse an early period of an ongoing transition in the road transport sector: the history of alternative transport fuels in Sweden 1974 to 2004.

  • 166.
    Sandén, Björn A.
    et al.
    Institutionen för energi och miljö, Miljösystemanalys, Chalmers tekniska högskola, Göteborg; Göteborgs miljövetenskapliga centrum (GMV).
    Jonasson, Karl
    Institutionen för energi och miljö, Miljösystemanalys, Chalmers tekniska högskola, Göteborg; Göteborgs miljövetenskapliga centrum (GMV).
    Variety Creation, Growth and Selection Dynamics in the Early Phases of a Technological Transition: The Development of Alternative Transport Fuels in Sweden 1974-20042005Report (Other academic)
  • 167.
    Sandén, Björn A.
    et al.
    Göteborgs miljövetenskapliga centrum (GMV) ; Institutionen för energi och miljö, Miljösystemanalys, Chalmers tekniska högskola, Göteborg.
    Jonasson, Karl
    Göteborgs miljövetenskapliga centrum (GMV) ; Institutionen för energi och miljö, Miljösystemanalys, Chalmers tekniska högskola, Göteborg.
    Karlström, Magnus
    Göteborgs miljövetenskapliga centrum (GMV) ; Institutionen för energi och miljö, Miljösystemanalys, Chalmers tekniska högskola, Göteborg.
    Tillman, Anne-Marie
    Göteborgs miljövetenskapliga centrum (GMV) ; Institutionen för energi och miljö, Miljösystemanalys, Chalmers tekniska högskola, Göteborg.
    LCA of Emerging Technologies: A Methodological Framework2005In: LCM 2005 - Innovation by Life Cycle Management, LCM 2005 - Innovation by Life Cycle Management , 2005, Vol. 1, p. 37-41Conference paper (Other academic)
  • 168.
    Schober, Benjamin
    University of Gävle, Faculty of Engineering and Sustainable Development.
    Membrane Stratified Solar Ponds2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project deals with the potential of membrane stratified solar ponds which consist of two water layers, where one is a salt solution here, and a separating translucent membrane. An experimental pond was set up to study the thermal behaviour of such collector systems. The input is mainly solar radiation, sometimes when the ambient temperatures are higher than the pond temperatures also heat from the environment is transferred into the pond.

    The measured temperatures of the pond, the ambient temperature, the global radiation and wind speed were the basis data for thermal calculations which showed that the pond was working well as a solar collector and thermal storage system all in one. Heat was not extracted from the pond however, only the losses to the environment were studied.

    It was found out that the pond temperatures were higher than the ambient temperature over the whole measurement period of 12 days, and insulation and pollution problems as well as future prospects and suggestions for further studies are discussed at the end of this paper.

  • 169.
    Schumm, Robert
    et al.
    University of Gävle, Department of Technology and Built Environment.
    Maier, Christoph
    University of Gävle, Department of Technology and Built Environment.
    Alternatives to the replacement of an electrical heating system2008Independent thesis Advanced level (degree of Magister), 10 points / 15 hpStudent thesis
    Abstract [en]

    The aim of this master thesis project is to make an energy survey for a group

    of apartments and suggestions to change the heating system from electricity to a more

    efficient one. There are in total 73 flats in 21 buildings. All flats are separated in several

    houses from two to five flats in one building. There are two different kinds of flats. One

    with three rooms in one floor, in the following referred to as ‘flat A’ and the other one

    with four rooms in two floors, in the following referred to as ‘flat B’. [1]

    In the area there are also two buildings for the commonalty. In these buildings there are a

    shelter and several common rooms like a storage and a laundry. In our work these two

    buildings are not included because they are used by everyone inside the community and

    we could not obtain exact values for the used electricity and the water consumption. So

    our work is specialised only on the residential houses.

    The first part of this thesis contains the energy balance for the different kinds of flats to

    see how much energy they consume for heating and hot tap water. To get theses values

    we have to analyse the total energy flow into one flat and compare it with the energy

    which is used because of transmission losses, ventilation losses, hot tap water, electricity

    for the household and natural ventilation and infiltration.

    The total energy consumption for flat A is about 19000 kWh per year and in flat B about

    23200 kWh per year. But the electricity which is used and has to be bought is about

    15600 kWh per year in flat A flat and 17600 kWh in flat B. The rest of the energy is from

    so called free heat caused by solar radiation and internal heat generation. [1]

    These numbers for the electricity need in one year create annual costs of about

    20000 SEK in flat A and 22500 SEK in flat B. To reduce these costs it is necessary to

    know where this energy goes and for what it is used.

    The important parts of the energy balance for this thesis are the transmission losses, the

    losses caused by natural ventilation and infiltration and the used energy for hot tap water.

    The losses caused by mechanical ventilation have also a significant value, but they would

    only affect the new heating system if the ventilation system would be connected to the

    new system. And the electricity used in the household for electrical devices can only be

    changed by the consumer himself. The part which is affecting the energy costs for the

    transmission and natural ventilation losses and the hot tap water sums up to 9240 kWh per

    year in flat A and flat B. This causes costs of about 10000 SEK per year.

    To reduce these costs it is necessary to change the actual heating system. In the following

    we analyse the saving potentials with a change to an air-water heat pump or with a

    connection to the local district heating network.

    The costs which can be saved with the installation of a heat pump sum up to about

    7000 SEK per year. The installation costs are about 100000 SEK to 125000 SEK

    depending on the different proposed models. If you consider that the existing electrical

    boiler has to be changed anyway in the next years the investment costs for the

    combination with a heat pump decreases. The payback time is then between 9½ and

    13½ years. With assumed increasing electricity prices of 5 % each year the payback time

    decreases to 8½ to 11 years.

    With a connection of each flat to the local district heating network the energy costs for

    heating and hot tap water decreases to 3200 SEK per year. Although the price per kWh for

    district heating is much lower than for electricity the costs are not decreasing a lot

    because of a high annual fixed fee of 7100 SEK. The saved money per year sums up to

    300 SEK and 1000 SEK depending on the electricity contract. The payback time for this

    alternative is between 50 and up to 160 years.

    An alternative to the exchange of the heating and hot water system is to change the actual

    heat exchanger of the ventilation system. With this measure the energy consumption can

    be reduced with less investment costs. The investment costs for a new heat exchanger are

    about 35000 SEK, including a new exhaust hood from the kitchen outwards to reduce the

    contamination of the filters in the heat exchanger. [1]

    The payback time ranges from 13 years in flat A to 21 years in flat B.

  • 170.
    Serra Ramon, Lourdes
    et al.
    University of Gävle, Department of Technology and Built Environment. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Montañes Asenjo, Alba
    University of Gävle, Department of Technology and Built Environment.
    District heating to replace an electrical installation2009Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    This project has been developed at the company Gavlegardarna. The companyowns a large part of the buildings of Gävle and two of them are the objective ofthe project. Gavlegardana is highly concerned about the environment; for thisreason, they cooperate on the subject with the energy management from theirtechnical department.

    Gävle is one of the Swedish cities where the DH (district heating) network isdistributed, arriving to most of the dwellings, industries and commercialbuildings. As DH uses environmentally friendly sources of energy,Gavlegardana is introducing it in its buildings.

    Electrical radiators and boilers were installed in the buildings when the price ofelectricity was more affordable than nowadays. The price of the electricity canbe considered 1,23 SEK/kWh while the DH price is 0,45 SEK/kWh.

    Consequently, this is another reason why the objective of the company at thepresent time is to replace electrical space heating systems by means of districtheating.

    The energy balance of the buildings is analysed in order to study their currentenergy situation. This entails the consideration of heat gains and lossesinvolved. The heat gains of the building are the heat from solar radiation whicharrives at the building trough the windows, the heat internally generated (bypersons, lighting and other devices) and the heat supplied. The heat losses are composed by the transmission trough walls and windows, the infiltrations, the heat used for hot tap water and the ventilation losses.

    An important part of the work required to calculate the energy balance hasconsisted of the collection and organization of all the data (areas, types ofmaterial, electrical devices, lighting, number of employees, opening hours...).This data comes from the drawings of the buildings provided by the companyand from the information gathered during the visits to the installation. In addition, the ventilation flows were measured in-situ using the tools provided by Theorells.

    Gavle Energi, the DH distributor company, has been contacted in order to fixthe cost and other details related to the district heating connection. The heatexchanger models, selected from Palmat System AB, are TP20 for Building Aand TP10 for Building B. TP20 provides 100 kW of heating and 0,4 l/s of hot tap water and TP10 provides 50 kW and 0,31 l/s respectively. The capital cost is 187500 SEK which includes the heat exchangers and the connection cost.

    As the secondary circuit is not currently installed because the existing system iscomposed by electrical radiators, the installation of the piping network in thebuilding has been designed. The radiators’ power is calculated taking intoaccount the need of heat in each room which is estimated as the transmissionlosses. This need of heat calculated is higher than the energy currently supplied which means that the thermal comfort is not achieved in all the rooms of the buildings.

    In spite of using more energy for space heating, the change of heat sourceentails a lower energy cost per year. The selected radiators are from Epeconand the investment cost (including the installation) is 203671 SEK. The brand of the selected pipes is Broson and the investment cost of the total piping system is 66000 SEK.

    The initial investment of the new installation is 457171 SEK, considering the DHconnection, heat exchangers, radiators and pipes. If the initial investment istotally paid in cash by the company the payback will be fulfilled in 6 years. Incase of borrowing the money from the bank (considering an interest rate of 5%), two possibilities can be considered: paying back the money in annual rates over 15 years or 30 years of maturity. The paybacks are 11 and 8 years respectively.

    After designing the DH piping system in the buildings, estimating the total costs of the investment and studying the project’s feasibility by suggesting different payment options, some possible energy savings are recommended.

     

    The first of the options refers to the transmission losses trough the windowswhose values’ are considerably high. Using a glass with a lower U-value, theselosses can decrease until 66% (with triple glass windows). Consequently, thepower required for space heating can also be reduced until 26%.

    Regarding the ventilation, rotating heat exchangers are currently used, whichentails the problem of smells mixture detected by the users of the buildings. By changing them with flat-plate heat exchangers, the problem is solved and the efficiency is increased from 66% to 85%. The new heat exchanger cost is340387 SEK and it has a payback of 10 years.

  • 171.
    Serrano Trullén, Javier
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energy Saving in Domestic Induction Heating Appliances: A High Efficiency Oriented Design of Inductors2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 172.
    Shimeles, Surafel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Thermo-economic Analysis of Retrofitting an Existing Coal-Fired Power Plant with Solar Heat2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At a time when global environmental change is posing a growing challenge to the world’s economy and creating uncertainties to livelihood of its inhabitants, Coal thermal power plants are under pressure to meet stringent environmental regulations into achieving worldwide set millennial goals for mitigating the effect of emission gases on the atmosphere. Owing to its abundance, it is unlikely to see the use of coal completely missing from the global energy mix within the next hundred years to come. While innovative emission reduction technologies are evolving for the better, trendy technological solutions which require reintegration of these coal plants with alternative greener fuels are growing at the moment.

    Among these solutions, the following paper investigates possible means for repowering a coal steam power plant with indirect solar heating solutions to boost its annual outputs. Two widely deployable solar thermal technologies, parabolic trough and Central tower receiver systems, are introduced at different locations in the steam plant to heat working fluid thereby enhancing the thermodynamic quality of steam being generated. Potential annual energy output was estimated using commercially available TRNSYS software upon mass and heat balance to every component of solar and steam plant. The annual energy outputs are weighed against their plant erecting and running costs to evaluate the economic vitality of the proposed repowering options.

    The results show that parabolic trough heating method could serve as the most cost effective method generating electricity at competitive prices than solar only powered SEGS plants. While cost may be acceptable in the unit of energy sense, the scale of implementation has been proven to be technically limited. 

  • 173.
    Ssembatya, Martin
    University of Gävle, Faculty of Engineering and Sustainable Development.
    PERFORMANCE EVALUATION OF A SOLAR   COOLING SYSTEM IN UAE – RAS AL KHAIMAH BY BOTH EXPERIMENT AND SIMULATION2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In United Arab Emirates (UAE), a huge proportion of electrical energy consumed in buildings is used to run air conditioning equipments. This is because UAE’s climate is characterized by very high ambient temperatures and high humidity, especially during summer periods. There is need to promote air conditioning systems that are run by renewable energy based power because of the environment threats and energy security negative issues associated with conventional fossil fuel – energy powered systems. The huge buildings’ cooling loads occur during periods of high solar insolation; this creates a huge potential of using solar powered cooling systems for air conditioning applications. However, the solar air conditioning systems still face a number of challenges in UAE which include; the availability of cheap electricity from fossil fuel resources and lack of government incentives to promote renewable energy resources. In order to understand the potential of applying solar cooling systems for air conditioning applications versus conventional systems, there was a need to experimentally and/or theoretically evaluate the performance of pilot solar cooling systems in UAE.     

    In this project, the performance of a 10 TR solar cooling system in Ras Al Khaimah (RAK) Emirate of UAE was evaluated by both experiment and theoretical simulation. TRNSYS, a transient – systems simulation software that was developed by Solar Energy Laboratory – University of Winsconsin, was used for the purpose of the theoretical simulations of the system. The solar cooling absorption equipment used for this study is an R&D system that was developed by CSEM – uae in RAK for the purpose of assessing the potential of applying solar cooling systems in UAE. The solar cooling system is based on absorption chilling technology run by hot water produced by a field of evacuated tube solar collectors.

    Experimental results were compared with TRNSYS – theoretical simulations results and areas of possible improvements in the solar cooling system were recommended. Results of the study show that the solar cooling system runs with a COP in the range of 0.60 – 0.80, with an average COP of 0.70. It was also observed that the inlet cooling and hot water temperatures to the absorption chiller have a huge impact on the performance of the solar cooling system. A need to isolate the absorption chiller hot water circuit from the hot water stratified tank by incorporation of a heat exchanger between the chiller and the stratified tank was also identified. This will help to improve the degree of stratification during the operation of the solar cooling system. Theoretical performance evaluation of the system using a typical TMY2 weather data shows that the system can meet its cooling requirement for at least eight (8) months of the year. In conclusion, this study has indicated that solar cooling for air conditioning application in UAE has a huge potential. However, further research is necessary to enable improvement of the performance of solar cooling systems and to assess the possibility of commercialization of such systems.

  • 174.
    Stojanovic, Bojan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Hallberg, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Akander, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building engineering.
    A steady state thermal duct model derived by fin-theory approach and applied on an unglazed solar collector2010In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 84, no 10, p. 1838-1851Article in journal (Refereed)
    Abstract [en]

    This paper presents the thermal modelling of an unglazed solar collector (USC) flat panel, with the aim of producing a detailed yet swift thermal steady-state model. The model is analytical, one-dimensional (ID) and derived by a fin-theory approach. It represents the thermal performance of an arbitrary duct with applied boundary conditions equal to those of a flat panel collector. The derived model is meant to be used for efficient optimisation and design of USC flat panels (or similar applications), as well as detailed thermal analysis of temperature fields and heat transfer distributions/variations at steady-state conditions; without requiring a large amount of computational power and time. Detailed surface temperatures are necessary features for durability studies of the surface coating, hence the effect of coating degradation on USC and system performance. The model accuracy and proficiency has been benchmarked against a detailed three-dimensional Finite Difference Model (3D FDM) and two simpler ID analytical models. Results from the benchmarking test show that the fin-theory model has excellent capabilities of calculating energy performances and fluid temperature profiles, as well as detailed material temperature fields and heat transfer distributions/variations (at steady-state conditions), while still being suitable for component analysis in junction to system simulations as the model is analytical. The accuracy of the model is high in comparison to the 3D FDM (the prime benchmark), as long as the fin-theory assumption prevails (no 'or negligible' temperature gradient in the fin perpendicularly to the fin length). Comparison with the other models also shows that when the USC duct material has a high thermal conductivity, the cross-sectional material temperature adopts an isothermal state (for the assessed USC duct geometry), which makes the ID isothermal model valid. When the USC duct material has a low thermal conductivity, the heat transfer course of events adopts a 1D heat flow that reassembles the conditions of the 1D simple model (for the assessed USC duct geometry); ID heat flow through the top and bottom fins/sheets as the duct wall reassembles a state of adiabatic condition.

  • 175.
    Sumner, Jonathon
    et al.
    École de technologie supérieure, Department of Mechanical Engineering.
    Garcia, Bibiana
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Bechmann, Andreas
    Risø National Laboratory / Technical University of Denmark.
    Prospathopoulos, John
    Masson, Christian
    École de technologie supérieure, Department of Mechanical Engineering.
    Cabezon, Daniel
    Sanz Rodrigo, Javier
    Odemark, Ylva
    Sørensen, Niels
    Risø DTU, Wind energy departmernt.
    Politis, Evangelos
    Chaviaropoulos, Panagiotis
    RANS simulations of Bolund2011In: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Article in journal (Refereed)
  • 176. Sundberg, Johan
    et al.
    Bisaillon, Mattias
    Haraldsson, Mårten
    Norrman Eriksson, Ola
    Systemstudie avfall i Göteborg: Delprojekt i Termisk och biologisk avfallsbehandling i ett systemperspektiv2010Report (Other academic)
  • 177. Sundberg, Johan
    et al.
    Bisaillon, Mattias
    Haraldsson, Mårten
    Norrman Eriksson, Ola
    Sahlin, Jenny
    Nilsson, Karolina
    Systemstudie avfall - sammanfattning: Sammanfattning av huvudresultat från projektet "Termisk och biologisk avfallsbehandling i ett systemperspektiv"2010Report (Other academic)
    Abstract [en]

    The report ”Waste treatment in a systems perspective - Summary report” summarizes the main results from the studies made within the research project “Thermal and biological treatment in a systems perspective”. The aim of the project is to develop tools and methodologies for systems analysis of waste management. The tools are used to evaluate waste treatment technologies for both household waste and commercial waste in a systems perspective. The focus is set to the municipal/regional waste and district heating system. However, to generate a full system analysis it is also important to consider effects that occur in the systems environment, such as the transport sector, the electricity production system, the agricultural sector etc.

    The report describes the benefits of using systems models for waste management planning by illustrating interesting results from the case studies made within the framework of the project. The report also presents the outcome from the whole project on an aggregated level as well as how the results and models have been used in different spin off projects.

    More thorough descriptions of models, methodologies and results are given in the reports for the two case studies, mainly. These reports presents two different case studies for municipal/regional waste management systems and are published by Waste Refinery, ”A systems study of the waste management system in Gothenburg” and “A systems study of the waste management system in Borås”. 

    The models and methodology developed in the research project has been used in several "spin-off projects". Some of the main results of these studies will be presented in this report, together with references to more extensive descriptions.

    We can conclude, after these three years of research, that the results from the system studies have been used for the practical waste management planning in both Borås and Gothenburg. The models and the results from the two case studies have also been used by other waste management systems in Sweden as well as for national waste management studies. The project has been presented internationally for researchers and practitioners where it has contributed with modelling knowledge and results presenting the effectiveness of integrated waste management combined with district heating systems. The results concerning options for reducing greenhouse gases have also reached the political arena in the EU, e.g. through ISWA to the Copenhagen meeting (COP15).

  • 178.
    Sundkvist, Åsa
    et al.
    Miljöstrategisk analys – fms, Institutionen för Samhällsplanering och miljö, KTH, Stockholm.
    Eriksson, Ola
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Glaumann, Mauritz
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Bergman, Sara
    Kemi & Miljö, Stockholm.
    Finnveden, Göran
    Miljöstrategisk analys – fms, Institutionen för Samhällsplanering och miljö, KTH, Stockholm.
    Stenbeck, Sten
    Kemi & Miljö, Stockholm.
    Wintzell, Helene
    Kemi & Miljö, Stockholm.
    Miljöklassning av byggnader: Inventering av metoder och intressenters behov2006Report (Other academic)
    Abstract [en]

    Denna rapport innehåller resultatet av projektets inledningsfas, kapitel 2 är en genomgång av politiska och andra mål för hållbar utveckling inom området byggnader med syfte att sätta miljöklassningssystemet i ett sammanhang, kapitel 3 är en redovisning av hur inledningsfasen genomförts, kapitel 4 innehåller resultatet av intervjuer med företag inom bygg och fastighetsbranschen om deras inställning till ett miljöklassningsystem samt intervjuer med aktörer som potentiellt kan skapa incitament för att företag och fastighetsägare ska ansluta sig till miljöklassningssystemet, kapitel 5 behandlar översiktligt genomgången av befintliga metoder för miljöbedömning av byggnader, kapitel 6 redovisar utgångspunkter för det fortsatta arbetet med ett miljöklassningsystem, kapitel 7 innehåller diskussion och slutsatser. Befintliga metoder för miljöbedömning av byggnader redovisas som informationsblad i bilaga 7 (svenska) och bilaga 10 (utländska).

  • 179.
    Sundqvist, Jan-Olov
    et al.
    IVL Svenska miljöinstitutet, Stockholm.
    Baky, Andras
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Björklund, Anna
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Carlsson, Magnus
    Institutionen för ekonomi, Sveriges lantbruksuniversitet, Uppsala.
    Eriksson, Ola
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Frost, Björn
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Granath, Jessica
    IVL Svenska miljöinstitutet, Stockholm.
    Thyselius, Lennart
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Systemanalys av energiutnyttjande från avfall - utvärdering av energi, miljö och ekonomi: Fallstudie - Stockholm1999Report (Other academic)
    Abstract [sv]

    I en systemanalys har energimässiga, miljömässiga och ekonomiska konsekvenser av olika system förhantering av kommunalt avfall i Stockholm studerats. I systemanalysen har olika kombinationer avförbränning, materialåtervinning av utsorterad plast och kartong, och biologisk behandling (rötning) avutsorterat lättnedbrytbart organiskt avfall studerats och även jämförts med deponering. I studien har endatormodell baserad på livscykelanalysmetodik (ORWARE) använts. Följande parametrar har använts för att utvärdera olika lösningar: förbrukning av energiråvaror, växthuseffekt, försurning, övergödning, bildning avmarknära ozon, tungmetallflöden, företagsekonomi och samhällsekonomi (samhällsekonomi innebär enhopviktning av företagsekonomi och miljöekonomi).

    Studien visar att minskad deponering till förmån för ett ökat utnyttjande av energi och material i avfall ärpositivt från såväl miljömässig och energimässig synpunkt som samhällsekonomisk synpunkt. Detta beror framför allt på att valet av behandlingsmetod har en påverkan utanför avfallssystemet på framställning avfjärrvärme, elektricitet, fordonsbränsle, plast, kartong och gödselmedel. Denna slutsats innebär att deponeringav energiinnehållande avfall ska undvikas i största möjliga utsträckning, p.g.a. det låga energi- och materialutnyttjandet och den miljöpåverkan som erhålls vid deponering.

    Förbränning bör utgöra en bas i Stockholms avfallssystem. Det är också gynnsamt ur mångaenergimässiga, miljömässiga och ekonomiska aspekter att ta emot avfall från en vidare region – i synnerhet avfall som annars skulle deponeras. Då avfallet väl är insamlat har även längre regionala transporter liten betydelse, under förutsättning att transporterna genomförs på ett effektivt sätt.

    Vid jämförelse mellan materialåtervinning och förbränning, samt mellan biologisk behandling och förbränning, har inga entydiga slutsatser kunnat dras vad gäller miljöpåverkan. Det finns fördelar och nackdelar med alla metoder.

    • Materialåtervinning av plast är samhällsekonomiskt jämförbar med förbränning och ger mindre miljöpåverkan och lägre energiförbrukning – detta under förutsättning att den återvunna plasten ersätter jungfrulig plast.
    • Materialåtervinning av kartong är samhällsekonomiskt och energimässigt jämförbar med förbränning, men har både miljömässiga fördelar och miljömässiga nackdelar.
    • Rötning av lättnedbrytbart organiskt avfall ger en högre samhällsekonomisk kostnad än förbränning ochhar både fördelar och nackdelar vad gäller miljöpåverkan. Det energimässiga resultatet beror på hur rötgasen används.
  • 180.
    Sundqvist, Jan-Olov
    et al.
    IVL Svenska miljöinstitutet, Stockholm.
    Baky, Andras
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Björklund, Anna
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Carlsson, Magnus
    Institutionen för ekonomi, Sveriges lantbruksuniversitet, Uppsala.
    Eriksson, Ola
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Frost, Björn
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Granath, Jessica
    IVL Svenska miljöinstitutet, Stockholm.
    Thyselius, Lennart
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Systemanalys av energiutnyttjande från avfall - utvärdering av energi, miljö och ekonomi: Fallstudie - Uppsala1999Report (Other academic)
    Abstract [sv]

    I en systemanalys har energimässiga, miljömässiga och ekonomiska konsekvenser av olika system för hantering av kommunalt avfall i Uppsala studerats. I systemanalysen har olika kombinationer av förbränning, materialåtervinning av utsorterad plast och kartong, och biologisk behandling (rötning och kompostering) av utsorterat lättnedbrytbart organisktavfall studerats och även jämförts med deponering. I studien har en datormodell baserad på livscykelanalysmetodik (ORWARE) använts. Följande parametrar har använts för att utvärdera olika lösningar: förbrukning av energiråvaror, växthuseffekt, försurning, övergödning, bildning av marknära ozon, tungmetallflöden, företagsekonomi och samhällsekonomi (samhällsekonomi innebär en hopviktning av företagsekonomi och miljöekonomi).

    Studien visar att minskad deponering till förmån för ett ökat utnyttjande av energi och material i avfall är positivt från såväl miljömässig och energimässig synpunkt som samhällsekonomisk synpunkt. Detta beror framför allt på att valet av behandlingsmetod har en påverkan utanför avfallssystemet på framställning av fjärrvärme, elektricitet, fordonsbränsle, plast, kartong och gödselmedel. Denna slutsats innebär att deponering av energiinnehållande avfall ska undvikas i största möjliga utsträckning, p.g.a. det låga energi- och materialutnyttjandet och den miljöpåverkan som erhålls vid deponering. Förbränning bör utgöra en bas i Uppsalas avfallssystem. Det är också gynnsamt ur många energimässiga, miljömässiga och ekonomiska aspekter att ta emot avfall från en vidare region – i synnerhet avfall som annars skulle deponeras. Då avfallet väl är insamlat har även längre regionala transporter liten betydelse, under förutsättning att transporterna genomförs på ett effektiv sätt.

    Vid jämförelse mellan materialåtervinning och förbränning, samt mellan biologisk behandling och förbränning, har inga entydiga slutsatser kunnat dras vad gäller miljöpåverkan. Det finns fördelar och nackdelar med alla metoder.

    • Materialåtervinning av plast är samhällsekonomiskt jämförbar med förbränning och ger mindre miljöpåverkan och lägre energiförbrukning – detta under förutsättning att den återvunna plasten ersätter jungfrulig plast.
    • Materialåtervinning av kartong är samhällsekonomiskt och energimässigt jämförbar med förbränning, men har både miljömässiga fördelar och miljömässiga nackdelar.
    • Rötning av lättnedbrytbart organiskt avfall ger en högre samhällsekonomisk kostnad än förbränning och har både fördelar och nackdelar vad gäller miljöpåverkan. Det energimässiga resultatet beror det på hur rötgasen används.
    • Kompostering av lättnedbrytbart organiskt avfall är samhällsekonomiskt jämförbar med rötning, men ger högre energiförbrukning och större miljöpåverkan.
  • 181.
    Sundqvist, Jan-Olov
    et al.
    IVL Svenska miljöinstitutet, Stockholm.
    Baky, Andras
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Björklund, Anna
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Carlsson, Magnus
    Institutionen för ekonomi, Sveriges lantbruksuniversitet, Uppsala.
    Eriksson, Ola
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Frost, Björn
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Granath, Jessica
    IVL Svenska miljöinstitutet, Stockholm.
    Thyselius, Lennart
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Systemanalys av energiutnyttjande från avfall - utvärdering av energi, miljö och ekonomi: Fallstudie - Älvdalen1999Report (Other academic)
    Abstract [sv]

    I en systemanalys har energimässiga, miljömässiga och ekonomiska konsekvenser av olika system för hantering av kommunalt avfall i Älvdalen studerats. I systemanalysen har olika kombinationer av förbränning, materialåtervinning av utsorterad plast och kartong, och biologisk behandling (rötning och kompostering) av utsorterat lättnedbrytbart organiskt avfall studerats och även jämförts med deponering. I studien har en datormodell baserad på livscykelanalysmetodik (ORWARE) använts. Följande parametrar har använts för att utvärdera olika lösningar: förbrukning av energiråvaror, växthuseffekt, försurning, övergödning, bildning av marknära ozon, tungmetallflöden, företagsekonomi och samhällsekonomi (samhällsekonomi innebär en hopviktning av företagsekonomi och miljöekonomi).

    Studien visar att minskad deponering till förmån för ett ökat utnyttjande av energi och material i avfall är positivt från såväl miljömässig och energimässig synpunkt som samhällsekonomisk synpunkt. Detta beror framför allt på att valet av behandlingsmetod har en påverkan utanför avfallssystemet på framställning av fjärrvärme, elektricitet, fordonsbränsle, plast, kartong och gödselmedel. Denna slutsats innebär att deponering av energiinnehållande avfall ska undvikas i största möjliga utsträckning, p.g.a. det låga energi- och materialutnyttjandet och den miljöpåverkan som erhålls vid deponering. Förbränning bör utgöra en bas för Älvdalens avfallssystem. Detta gäller även om avfallet måste transporteras till en annan region för behandling – i synnerhet om avfallet annars skulle deponeras. Då avfallet väl är insamlat har även längre regionala transporter liten betydelse, under förutsättning att transporterna genomförs på ett effektiv sätt.

    Vid jämförelse mellan materialåtervinning och förbränning, samt mellan biologisk behandling och förbränning, har inga entydiga slutsatser kunnat dras vad gäller miljöpåverkan. Det finns fördelar och nackdelar med alla metoder.

    • Materialåtervinning av plast är samhällsekonomiskt jämförbar med förbränning och ger mindre miljöpåverkan och lägre energiförbrukning – detta under förutsättning att den återvunna plasten ersätter jungfrulig plast.
    • Materialåtervinning av kartong är samhällsekonomiskt och energimässigt jämförbar med förbränning, men har både miljömässiga fördelar och miljömässiga nackdelar.
    • Rötning av lättnedbrytbart organiskt avfall ger en högre samhällsekonomisk kostnad än förbränning och har både fördelar och nackdelar vad gäller miljöpåverkan.
    • Kompostering av lättnedbrytbart organiskt avfall är samhällsekonomiskt jämförbar med rötning, men ger högre energiförbrukning och större miljöpåverkan.
  • 182.
    Sundqvist, Jan-Olov
    et al.
    IVL Svenska miljöinstitutet, Stockholm.
    Baky, Andras
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Björklund, Anna
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Carlsson, Marcus
    Institutionen för ekonomi, Sveriges lantbruksuniversitet, Uppsala.
    Eriksson, Ola
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Frostell, Björn
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Granath, Jessica
    IVL Svenska miljöinstitutet, Stockholm.
    Thyselius, Lennart
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Systemanalys av energiutnyttjande från avfall - utvärdering av energi, miljö och ekonomi: Översiktsrapport1999 (ed. 1)Book (Other academic)
    Abstract [sv]

    I en systemanalys har energimässiga, miljömässiga och ekonomiska konsekvenser av olika system för hantering avkommunalt avfall studerats. I systemanalysen har olika kombinationer av förbränning, materialåtervinning av utsorteradplast och kartong, och biologisk behandling (rötning och kompostering) av utsorterat lättnedbrytbart organiskt avfallstuderats och även jämförts med deponering. 1 studien har en datormodell baserad på livscykelanalysmetodik (ORWARE)använts. Tre olika kommuner har studerats: Uppsala, Stockholm och Älvdalen. Följande parametrar har använts för attutvärdera olika lösningar: förbrukning av energiråvaror, växthuseffekt, försurning, övergödning, bildning av marknäraozon, tungmetallflöden, företagsekonomi och samhällsekonomi (samhällsekonomi innebär en hopviktning avföretagsekonomi och miljöekonomi).

    Studien visar att minskad deponering till förmån för ett ökat utnyttjande av energi och material i avfall är positivt frånsåväl miljömässig och energimässig synpunkt som samhällsekonomisk synpunkt. Detta beror framfor allt på att valet avbehandlingsmetod har en påverkan utanför avfallssystemet på framställning av fjärrvärme, elektricitet, fordonsbränsle,plast, kartong och gödselmedel. Denna slutsats innebär att deponering av energiinnehållande avfall ska undvikas i störstamöjliga utsträckning, p.g.a. det låga energi- och materialutnyttjandet och den miljöpåverkan som erhålls vid deponering.

    Förbränning bör utgöra en bas i avfallssystemet för vardera av de tre kommunerna, även om avfallet måste transporterastill en regional anläggning. Då avfallet väl är insamlat har även längre regionala transporter liten betydelse, underförutsättning att transporterna genomfors på ett effektiv sätt.

    Vid jämförelse mellan materialåtervinning och förbränning, samt mellan biologisk behandling och förbränning, har ingaentydiga slutsatser kunnat dras vad gäller miljöpåverkan. Det finns fördelar och nackdelar med alla metoder.

    • Materialåtervinning av plast är samhällsekonomiskt jämförbar med förbränning och ger mindre miljöpåverkan ochlägre energiförbrukning - detta under förutsättning att den återvunna plasten ersätter jungfrulig plast.
    • Materialåtervinning av kartong är samhällsekonomiskt och energimässigt jämförbar med förbränning, men har bådemiljömässiga fördelar och miljömässiga nackdelar.
    • Rötning av lättnedbrytbart organiskt avfall ger en högre samhällsekonomisk kostnad än förbränning och har bådefördelar och nackdelar vad gäller miljöpåverkan. Det energimässiga resultatet beror det på hur rötgasen används.
    • Kompostering av lättnedbrytbart organiskt avfall är samhällsekonomiskt jämförbar med rötning, men ger högreenergiförbrukning och större miljöpåverkan.
  • 183.
    Sundqvist, Jan-Olov
    et al.
    IVL Svenska miljöinstitutet, Stockholm.
    Baky, Andras
    Institutet för jordbruks- och miljöteknik (JTI), Uppsala.
    Carlsson, Magnus
    IVL Svenska miljöinstitutet, Stockholm.
    Eriksson, Ola
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Hur skall hushållsavfallet tas om hand?: Utvärdering av olika behandlingsmetoder2002Report (Other academic)
    Abstract [sv]

    I en systemanalys har konsekvenser rörande energiförbrukning, miljöpåverkan och ekonomi studerats förolika system för hantering av kommunalt avfall. I systemanalysen har olika kombinationer av förbränning, deponering, materialåtervinning av utsorterad plast och kartong, och biologisk behandling (rötning ochkompostering) av utsorterat lättnedbrytbart organiskt avfall studerats. I studien har en datormodell baserad på livscykelanalysmetodik (ORWARE) använts. Studien baseras på en modellkommun. I en känslighetsanalys har inverkan av olika kommunspecifika parametrar och anläggningsspecifika parametrar studerats. Det slutliga resultatet bedöms täcka ett mycket stort antal kommuntyper. Följande parametrar har använts för attutvärdera olika lösningar: förbrukning av energiråvaror, växthuseffekt, försurning, övergödning, bildning av marknära ozon, tungmetallflöden, företagsekonomi (i livscykelperspektiv) och samhällsekonomi (samhällsekonomi innebär en viktning av företagsekonomi och miljöekonomi) - i grundfallet räknashushållens arbete inte in i den samhällsekonomiska kalkylen. Vi har kommit fram till följande slutsatser.

    Deponering bör i allmänhet undvikas för avfall som kan förbrännas, rötas, komposteras eller materialåtervinnas.

    Möjlighet till förbränning av avfall bör alltid finnas. Detta gäller även om avfallet måste transporteras till en regional anläggning. Eftersom det inte går att uppnå 100 % återvinningsgrader för exempelvis plast,kartong och returpapper, kommer det alltid att finnas en viss mängd brännbart avfall som måste tas omhand vid sidan av materialåtervinningssystemen och eventuella system för biologisk behandling.

    Materialåtervinning, rötning och förbränning bör inte ses som konkurrerande metoder, utan mer somkompletterande metoder. Det är svårt att dra entydiga slutsatser om vilken metod som är ”bäst”. Det finns fördelar och nackdelar med alla metoder. I systemperspektivet för en hel kommun ger materialåtervinning eller rötning mycket små skillnader mot förbränning. Kompostering (sträng kompostering) av lättnedbrytbart avfall har nästan inga miljömässiga fördelar gentemot förbränning eller gentemot rötning.

    Om man räknar in hushållens arbete i den samhällsekonomiska kalkylen blir materialåtervinning samhällsekonomiskt dyrare än förbränning. Förbränning, rötning och kompostering kräver ungefär lika mycket arbete av hushållen och skillnaderna mellan dessa påverkas mycket lite av om hushållens arbete räknas in.

    Transporter av avfall, sedan det väl är insamlat, är av begränsad betydelse vad gäller miljöpåverkan, energiförbrukning och kostnader, under förutsättning att transporterna genomförs på ett effektivt sätt. Hushållens transporter (med personbil) kan påverka både resultatet (i ogynnsam riktning för källsortering).

    Olika insamlingssystem påverkar det totala resultatet i mycket liten utsträckning beträffande miljöpåverkan och energiförbrukning. En förtätning av återvinningsstationer från områdesnära till återvinningsgårdar som är mer kvartersnära ger ingen avgörande påverkan på miljöpåverkan eller samhällsekonomi (exklusive hushållens arbete) men leder till mindre arbete för hushållen.

  • 184.
    Sylva, Kappina Kasturige Kamani
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. OUSL.
    Modeling and Optimization of Energy Utilization of Air Ventilation System of an Auditorium2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Maintaining IAQ (Internal Air Quality) and thermal comfort of occupants in buildings have been a challenge to overcome satisfying the two ends: criteria for sustainability and cost effectiveness. Although there was a movement for mechanical ventilation systems in the recent past, in addition to the cost involved, they are found to not deliver the desired air quality, lead to social consequences such as sick building syndrome, contribute to environmental consequences related to ozone-depleting substances with increasing energy consumption, generate noise and having difficulties in cleaning and maintaining. These consequences compelled research on natural ventilation systems, which were used in ancient buildings. Although it has been found that natural ventilation of buildings can become a substantial architectural design tool that leads to “breathing architecture,” fluctuations in indoor temperature and air quality makes depending entirely on natural ventilation less effective. The combination of natural and mechanical ventilation, the hybrid ventilation or mixed-mode ventilation, systems utilizes advantages and eliminates drawbacks from both mechanical and entirely dependent natural ventilation systems. Hybrid ventilation systems, which have been utilized in historical buildings, with less investment cost and reduction of energy usage have been found to be a solution to provide acceptable standards of IAQ and thermal comfort through natural air circulation in buildings. This research study was carried out to verify the effectiveness of a hybrid ventilation system in an auditorium built around 60 years back for its effectiveness as a provider of thermal comfort to its occupants. Computational Fluid Dynamic (CFD) modeling was carried out on a Finite Element (FE) model owing to its capability of offering a wide range of flexible analytical solutions, lower realization time and comparative cost effectiveness to experimental methods of modeling. This verification of the system has revealed that hybrid ventilation systems could provide effective thermal comfort in buildings designed specifically to allow circulation of air through the system. The results of the study were in agreement with measured data and the expected flow of air through the building when the thermal load due to metabolism of occupants was not included in the analysis. In addition, the expected results complied with similar studies on natural/hybrid ventilation systems. With the addition of the thermal load, as a uniform heat flux from the flow of the auditorium, it was observed that the conditioning of the air throughout the space was better than the without thermal load scenario. In the case modeling people as cylinders, with a convective heat flux, it was observed that the air flow direction changes and the seating level of the auditorium do not get sufficient air flow to maintain a comfortable air quality.  Ineffective simulation of the inlet louver was assumed to be the primary reason for this scenario and other reasons such as the seating arrangement modeling too could have effects on the result. As conclusions of the study it was found that the whole building system properties have to be selected, as the control component to produce operating commands, to circulate air through the building in accordance with the air flow: both velocity and patterns, required to maintain thermal comfort of all occupants. Air inflow could be through windows as acquisition components to collect indoor and outdoor climatic parameters and air outflow could be mechanically controlled through exhausted fans turning on or off as the operating component in the system. The result of the study ensures the method of solutions through CFD to be utilized to provide effective and less costly path to verify systems such as natural or hybrid air flow systems through buildings.  The whole system studied could be applied with suitable contextual modifications to any new location, with similar cost effective modeling, to produce less fuel consuming building systems leading to sustainability of built environment. 

  • 185.
    Thomas, Alsmyr
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Injustering och optimering av värmesystem i befintlig fastighet2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 186. Thygesen, Richard
    et al.
    Eriksson, Ola
    Gustafsson, Mattias
    Karlsson, Björn
    Nära noll-energi-byggnaders energianvändning: Analys av solel, energieffektivisering och val av uppvärmingsform genom simuleringar av byggnader och energisystem2017Report (Other academic)
    Abstract [en]

    The EU Directive on Energy Performance of Buildings states that it is up to the individual Member States to define and implement the concept of nearly zero-energy buildings (NZEB). Given the revised Directive on Energy Performance of Buildings, the National Board of Housing, Building and Planning (Boverket) has developed more stringent energy requirements active from January 1st, 2013 (BBR 2012). These requirements determine the maximum levels of energy which may be used for heating, comfort cooling, hot tap water and building electricity. Non elec-trically heated buildings may have a factor 1.6 times higher specific energy usage than electrically heated buildings, resulting in a building with heat pump can be erected significantly less energy efficient than a building heated by district heating. Solar energy (power or heat) and the heat that a heat pump takes from the sur-roundings used directly in the building count as energy efficiency. In the Board's proposed regulations there is no description of how solar electricity will be han-dled. This gives rise to problems in building planning phase.

    In this report, focus has been set on using simulations of energy consumption in buildings to illustrate the problem of the definition of nearly zero-energy build-ings. The following impact assessments have been carried out:

    1. Highlight the problem of how the HVAC system affect the specific energy use of buildings using different heating systems (geothermal heat pump and dis-trict heating)
    2. Highlight how the BBR and NNEB definitions affects renovations in terms of specific energy use and evaluate the measures that are most profitable for the property owner.
    3. Highlight how the requirements of the NNEB definition affects the chosen heating systems in new buildings within the district heating area.

    The findings based on the simulations are as follows:

    The National Board of Housing, Building and Planning 's proposed near-zero en-ergy building definition enhances the ability to build systems combinations with geothermal heat pump and solar systems that provide buildings with low primary energy numbers. The primary energy number for a building heated by district heating is affected marginally by the installation of a solar energy system. Even relatively small solar system sizes provide the bulk of the reduction of primary energy number for all system combinations.

    In the Board's regulatory proposals there are no mandatory requirements regard-ing renovation, thus they are not ruling regarding renovations.

    The NNEB definition or regulation proposal for Chapter 9 of the Building Regula-tions makes it possible for new buildings to receive very low primary energy num-bers if equipped with geothermal heat pump. If the system design is introduced in buildings within the district heating area, it may lead to an increase in global car-bon dioxide emissions unless the CO2 emissions from electricity are moderate as for Nordic mix.

  • 187.
    Vachaparambil, Kurian Jory
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Karimipanah, Taghi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Comparative Numerical Study of the Indoor Climate for Mixing and Confluent Jet Ventilation Systems in an Open-plan Office2018In: Proceedings of the 4th international Conference on Building Energy & Environment, Melbourne: Conference On Building Energy & Environment - COBEE2018, Melbourne Australia , 2018, p. 73-78Conference paper (Refereed)
  • 188.
    Vestling, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Barriärer och drivkrafter för effektiviseringsamt förutsättningar vid spillvärmeåtervinning: En fallstudie av Tegera Arena2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Fokus på energianvändning är idag stort då forskare konstaterar att antalet naturkatastrofer som indirekt härrör från den globala energikonsumtionen ökar. Sverige står idag för 0,5 % av den totala energianvändningen globalt. Dock ligger Sverige och Europa i toppen vad det gäller energianvändning per capita. Den slutliga elenergi användningen 2015 var 30 % av den totala slutliga energianvändningen, till dessa slutanvändare hör ishallar, så som Tegera arena, som använder genomsnittlig 1000MWh/år köpt energi.

    Tegera arena förknippas troligtvis först och främst med Leksands IF hockeylag. Men utöver ishockey används arenan för andra evenemang och har en verksamhetstid under den större delen av året. Arenans energibehov är idag något större i jämförelse med genomsnittet för andra arenor med samma publikkapacitet och detta har uppmärksammats av föreningen.

    Ett samarbete mellan Leksands IF och det lokala fjärrvärmebolaget Dala Energi eftersöks. Detta utifrån den spillvärmeåtervinning från arenan som skulle kunna vara intressant för både föreningen, som internvärme, och energibolaget, i form av tillskottsenergi till fjärrvärmenätet. Detta kommer att undersökas med hjälp av andrahandsdata från både energibolaget och från föreningen. Genom analyser av dessa data kommer bottom-up och top-down-metod att användas. Resultatet av denna metod kommer sedan att jämföras med den totala verkliga användningen och sedan diskutera eventuella avvikelser. Även kommer intervjuer att göras för att studera vilka de främsta motsättningar och drivkrafter som föreligger hos föreningen för energieffektiviseringar.

    Resultatet från fallstudien visar att nära en tredjedel spillvärmeenergi används idag för det interna värmesystemet. Dock finns det ytterligare energi att använda internt. Detta utan att öka energiinnehållet med värmepump. Resultatet visar även att ekonomi är den största barriären men tillika drivkraft. Dessa två är inte ovanliga bland andra branscher, visar undersökningar. Annan drivkraft som föreningen anser vara betydande är fungerande installationer, då det idag finns förkommer problem med nuvarande tank för varmvattenackumulation.

    För utökad återvinning av spillvärme ges fyra förslag för det interna värmesystemet samt två stycken för den extern distribution. Att installera nya ackumulatortankar anges som högsta prioritet vid utökad återvinning vilket skulle ge en beräknad besparing på 90 kkr/år. Vid extern distribution föreslås det att leverera den lågtempererade spillvärmeenergin till annan närliggande varmvattenanvändare med höga laster. Detta i förstahand utan att använda sig av värmepump och istället använda spillvärmen till förvärmning.

  • 189.
    Vicente Pina, Alejandro
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Analysis and consumption troubleshooting in a heat pump2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    One of the European Union priorities is the promotion of electricity generated from renewable energy sources. This is due to reasons of security and diversification of energy supply, environmental protection, reducing external dependence of the European Union (EU) in its energy supply and economic and social cohesion.

    The members of the EU as a whole, constitute the major world power in what concerns the development and application of renewable energy. The Maastricht Treaty assigned the EU's objectives of promoting sustainable growth respecting the environment. Meanwhile the Treaty of Amsterdam incorporated the principle of sustainable development in the objectives of the EU.

    The price support system for renewable energy currently prevailing in the EU is the system Renewable Energy Feed-in Tariffs (REFIT). The geothermal energy is considered as one of these renewable energies, so, it gets benefits from this system.

    In the concrete case of Sweden, almost 40% of the energy used is represented by the residential and services sector. So, to maximize the usage of renewable energy in these sectors is a priority for the country. In this way, low enthalpy geothermal energy is the easiest way of using geothermal energy in residential buildings.

    In this project it is studied a block of flats in N. Kungsgatan 37-43 (Gävle), whose heating and tap hot water system are handled by a geothermal heat pump combined with district heating. The system has been analysed because the consumption of electricity was higher than expected and this is a problem when the energy saving is the objective.

    For the analysis, different elements of the installation have been checked to verify if they are working correctly. For example, if the temperature sensors are giving properly information to the controlling system and the effectiveness of heat exchangers is the correct. The whole installation has also been carefully inspected with a thermal camera to check possible liquid or heat leakages in the machines room.

    Finally, after study the heat pump, the conclusion is that the problem is in the geothermal part of the heat pump, because the probes are not able to supply the required heat to the system. This is due to the geothermal installation was designed for another heat pump which was installed in the building some years ago. However, when the new installation was done in 2010, the geothermal installation was not changed for the new heat pump installation.

  • 190.
    Viguer Torres, Luis
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Fatas Perez, Borja
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Computer simulations of temperature and flow field in industrial spaces using confluent jets air supply method2012Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ventilation systems are closely connected to indoor environment. In industrial spaces it has a major impact due to air quality and thermal comfort requirements, which leads into health and economy improvements.

    Confluent jets ventilation system has been assess in Söderhamn Eriksson, a machinery company located in Mariannelund, Sweden, since it has been proved as the best ventilation performance. Moreover this system is worthy for both heating and cooling purposes, although just heating case will be developed in this thesis.

    By means of modelling software such as Gambit and Airpak, the company’s case could have been analyzed via Computational Fluid Dynamics (CFD) software, i.e. Fluent. The analyzed models were accepted after a thorough study of meshing parameters, bearing in mind computational limitations.

    Every temperature data gathered from simulation results has been verified with infrared camera figures taken at the company, thus contributing to reach reliable conclusions. As it is inferred from previous papers and empiric theory, the flow field observed is also justified. Then, thermal comfort and air quality analysis relies on consistent facts.

    It has been found that current ventilation at the company is slightly misadjusted, since supplied air’s temperature and velocity are slightly off point. Therefore, it is recommended to reduce these values to reach better working environment.

  • 191.
    VILAFRANCA MANGUÁN, ANA
    University of Gävle, Department of Technology and Built Environment. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Convesion of industrial compression cooling to absorption cooling in an integrated district heating and cooling system2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CHP plant was built. It is awarded with the electricity certificate system.

    The study investigates the possibility for converting some of the compression cooling to absorption cooling and then analyzes the effects of the district heating system through MODEST optimizations. The effects of the analysis are studied in a system composed by the district heating system in Södertälje and cooling system in Astra Zeneca. In the current system the district heating production is from boiler and compression system supplies cooling to Astra Zeneca. The future system includes a CHP plant for the heating production, and compression system is converted to absorption system in Astra Zeneca. Four effects are analyzed in the system: optimal distribution of the district heating production with the plants available, saving fuel, environmental impact and total cost. The environmental impact has been analyzed considering the marginal electricity from coal condensing plants. The total cost is divided in two parts: production cost, in which district heating cost, purchase of electricity and Emissions Trading cost are included, and investment costs. The progressive changes are introduced in the system as four different scenarios.

    The introduction of the absorption machines in the system with the current district heating production increases the total cost due to the low electricity price in Sweden. The introduction of the CHP plant in the district heating production supposes a profit of the production cost with compression system due to the high income of the electricity produced that is sold to the grid; it profit increases when compression is replaced by absorption system. The fuel used in the production of the future system decreases and also the emissions. Then, the future system becomes an opportunity from an environmental and economical point of view. At higher purchase electricity prices predicted in the open electricity market for an immediately future, the future system will become more economically advantageous.

     

     

  • 192.
    Wanasinghe, Buddhika Hasantha
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Steam driven boiler feed pumps for Lakvijaya Power Station, Sri Lanka2017Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Energy saving in coal power plants is a popular topic in present days with the global energy crisis. Internal electricity demand or auxiliary power consumption is an energy portion related with equipment supportive to the main equipment, which is unavoidable but with a proper investigation, some amount of this energy can be saved either by introducing thermally efficient auxiliary equipment or improving efficiencies of available equipment.

    Out of the various auxiliary equipment, the driving motor of boiler feed pump is the largest power consumer of internal electricity demand in 3x300 MW sub-critical Lakvijaya Power Station in Sri Lanka. So it is obvious that prime movers of feed pumps could be contributed for a large percentage of the losses. So it was decided to find out how to minimize the losses related to Boiler Feed Pump (BFP) system using small steam turbine to drive the BFP.

    The widely used alternatives for the BFP drivers are condensing type and back pressure type steam turbines. Eleven (11) different configurations of Condensing type, back pressure type and also extraction back pressure type turbines were considered and software programs for each configuration were implemented using Engineering Equation Solver (EES) software. The considered configurations are different to each other by inlet steam thermodynamic parameters, steam flow rate, exhaust thermodynamic steam parameters and intermediate extraction parameters etc.

    Thermodynamic analysis ended up with interesting solutions while all the configurations are giving improved efficiencies than existing electrical motor driven mode. But some of them had not improved their net output and hence there were no gain in net generator power output although the efficiencies are higher. Out of other configurations with improved net output and efficiency, the case with back pressure turbine arranged parallel to the HP turbine had the highest net output gain with better improvement in efficiency without changing the input power to the boiler. Considering the CO2 , SOx and NOx emissions, it was cleared that power plant with suggested BFP modes will give more clean energy than existing power plant.

    Considering the partial loads behavior it was observed that power plant with Back pressure turbine, steam extracted from HP turbines inlet for prime movers of boiler feed pumps is more thermodynamically economical than existing power plant.

    Annual financial saving with BFP configurations with positive net output gain and zero boiler input gain were calculated and it will be in between 0.46 and 2.72 UDS million / Year.

  • 193.
    Wang, Chengju
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Energy use and energy saving in buildings and asthma, allergy and sick building syndrome (SBS): a literature review2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy use in buildings is an important contribution to global CO2 emissions and contributes to global warming. In recent years, there has been concern about creating energy efficiency buildings, green buildings and healthy buildings but this development needs guidance by multidisciplinary scientists and experts. Since energy saving can influence the indoor environment in different ways, epidemiological research is needed in different climate zones to evaluate the health consequences of making the buildings more energy efficient. Epidemiological studies and modelling studies are available on health effects and indoor effects of energy conversation, improved thermal insulation, increased air tightness and creating green buildings. The health-related literature on this issue was reviewed, by searching scientific articles in the medical Database PubMed and in the general database Web of Science as well as Nature database. In this literature review, 53 relevant peer reviewed articles on health effects of energy use and energy saving were found. Most of the studies had investigated residential buildings. One main conclusion from the review is that combined energy efficiency improvements in buildings can be associated with improvement of general health, such as less asthma, allergies, sick building syndrome (SBS) symptoms, respiratory symptoms, and reduced cold-related and heat-related mortality. Moreover, combined energy efficiency improvements can improve indoor air quality, increase productivity and satisfaction and reduce work leave and school absence. Effective heating of buildings can reduce respiratory symptoms and reduce work leave and school absence. However, some potential health problems can occur if increased energy efficiency will reduce ventilation flow. Energy saving by increasing air tightness or reducing ventilation is associated with impaired indoor air quality and negative health effects. In contrast, improved ventilation may reduce SBS, respiratory symptoms and increase indoor air quality. Installation of mechanical ventilation can solve the negative effects of making the building construction in dwellings more air tight. In future research, more studies are needed on health impacts of single energy efficiency improvement methods. Existing studies have mostly used a combination of improvement methods. In addition, modelling software programs should more often be used, since they can take into account effects of different energy efficiency improvement methods on indoor air quality in different types of buildings and in different climates.

  • 194.
    Weerathunga, Lahiru
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. Open University, Sri Lanka.
    ANALYSIS FOR AN ECONOMICALLY SUITABLE COAL TO PUTTALAM COAL POWER STATION TO RUN THE PLANT IN FULL LOAD CAPACITY2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Sri Lanka is an island at the Indian Ocean with 65234 km2 and it has a power demand of 2000 MW. The hydro power was the main power source before year 2000, after maximum usage of hydro power Sri Lanka installed fossil fuel power plant to achieve the demand. Then the electricity price gradually increased due to higher increment of fuel price. As the solution for this higher price of electricity the government has to go to new profitable power source the coal power. Finally year 2011 Puttalam coal power plant 300 MW x 1 was installed with the hope of providing the low cost reliable energy supply to Sri Lanka and it will be extended to 300MW x 3 plan in year 2015. Therefore the puttalam coal power plant is the key power plant to the Sri Lankan power generation and it is expected to have the maximum output (base load) to the Power demand of Sri Lanka.

    Sri Lanka is a tropical country and it has two different weather seasons as rainy season and dry season. The puttalam power plant situated at Kalpitiya peninsula and it has normally dry weather condition, Months of April, October November and December have heavy rain condition (Meteorological Department, Sri Lanka, 2012). The puttalam coal power plant may not achieve full load because of high moisture content at rainy season. So this Thesis carried out to find the capability to achieve the full load with available plant, plant capacity by using different coal qualities. Then find the economical benefits and effect on the environment with the recommended coal for different seasons and also design a storage plan to coal storage at existing coal yard.

    Based on the historical data and the Meteorological department rain fall data and by doing a technical analysis the recommended coal type was selected and the capability of plant equipment capacity to the recommended coal to achieve the full load was analyzed. Then the coal storage plan was designed according to annual requirement of the different recommended coal and economical benefit was analyzed by considering last year cost for generated power and the generation cost, if recommended coal is used for last year. Finally flue gas analysis was carried out for the recommended coal to find the effect on the environment.

    The recommended coal for rainy season is with the heating value of 6600 kcal/kg and for dry season it is 6300 kcal/kg. The capacities of main boiler and other plant equipments are capable for the recommended coal to achieve the full load of the plant. Then the design of the coal storage plan was given under figure 4.2 and table 4.1. It was calculated that a profit of 3.932 million US$ can be achieved by using the recommended  coal for the last year and also when compared with the changing price of oil and coal it will be more profitable for the future. Because the oil price increases very rapidly and the increase in coal price is very low compared to the oil price. Finally the SOx and NOx emissions from recommended coal were analyzed and it was within the environmental limits because of the high quality emission reduction plant equipments.

  • 195.
    Xie, Tian
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Multi-zone modeling of Thermal Comfort and Energy Consumption of a hospital ward: a summer case study2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Hospital is of interest when consider its especial function. Because of the obviously different between the normal residential buildings, the requirement of hospitals’ indoor climate strictly differs from other buildings.

    The author starts this report by briefly stating the building construction currently. Surrounded the topic of thermal comfort and energy consumption, many suggestion and options came out in this report to develop a better condition.

    Firstly, the introduction of the hospital buildings requires the background of the hospital object and the purpose to this report will be stated.

    Secondly, the simulation tool and how to use this tool simulate our real case are introduced.

    Then, the summer case is investigated by this tool after the model is proved to be validated.

    Finally, the improvement of establishing a better indoor environment is raised and the results of improvement and conclusion can be found. The final result will show the optimal solution that discovered by this study after compared different alternatives carefully.

  • 196.
    Yin, Shi
    et al.
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
    Li, Yuguo
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Lam, Kitming
    Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China.
    The effect of building spacing on near-field temporal evolution of triple building plumes2017In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 122, p. 35-49Article in journal (Refereed)
    Abstract [en]

    Building plume is important for ventilation and pollutants dispersion along and above buildings in an urban canopy layer. This study fundamentally explores the merging process and temporal penetration of triple uniformly distributed starting building plumes, with a focus of the spacing effect on near-field flow dynamics. Instantaneous velocity and vorticity distributions, penetrating velocities, and stream-wise penetrated heights are quantitatively examined using 2-D particle image velocimetry (PIV) measurements at spacing ratios S/W (building spacing/building width) of 0.2, 0.5, and 1.0. We identified a four-stage merging progress and captured three main spacing-induced merging features. A compact layout at S/W = 0.2 introduces a strong upward channel flow. The wall flows beside the channel tend to draw together first and the unstable channel flow determines the flow pattern transition. In contrast, wider layouts at S/W = 0.5 and 1.0 exhibit intensive downward flow. The wall flows tend to exhibit self-merging initially and the downstream natural swaying motion dominates the merged pattern variations. Merging effect and buoyancy force jointly determine the temporal penetrating velocities. Temporal series of maximum axial velocities above the middle source fits into a power law profile at S/W = 0.2 but a linear function of time at S/W = 0.5 and 1.0. The normalized penetrated heights at S/W = 1.0 are notably faster than in the other two cases before the normalized time is at 3.00 probably because the weaker entrainment and interaction with neighbors lead to less energy and momentum dissipation, quicker self-merging, and faster penetration.

  • 197.
    Zana, Tahsin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energimässig jämföelse med investeringskalkyl av två förskolor2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    This thesis includes an energy survey of the Herrgården pre-school, which has a modern heating- and ventilation system, and a comparison with Östers pre-school which has an older system. An energy survey of Östers pre-school has already been done by a group of three students and all the calculations and values have been collected from that survey. As of today, both pre-schools are heated thru district heating. It will be much easier to make smart and feasible energy-saving-measures by first conducting the energy survey.

    Herrgården pre-school in Gävle houses 81 children, therteen teachers, one cleaner and one cook. It was finished in the middle of 2009 and the staff has been very pleased with the in-door climate. In the energy balance added heat was calculated as district heat, solar radiation body heat and heat from lighting and other appliances. As lost heat- transmission, tap water heating, heating of ventilating air and excess ventilation was taken in to account.

    At Öster pre-school there are 66 children, twelve teachers and two economists. The pre-school was built in 1973. Gävlefastigheter which administrates both buildings are planning to change the ventilation system at Östers since it has been inferior and the staff has been experiencing bad in-door climate.

    The purpose of this thesis is to conduct a survey of how to economically reduce the energy consumption and to establish a good in-door climate like the Herrgården pre-school. The methods used have been to make a few visits on site to collect data.

    After finishing the survey it was shown that one could save 76,23 MWh/year if Öster has the same U-values as Herrgården for its´ roofs, floors walls and windows and a ventilation heat exchanger with 70% efficiency. However, none of these approximate calculations of installations at Östers pre-school turned out to be financially feasible.

     

  • 198.
    Ängskog, Per
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics. Department of Electromagnetic Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Bäckström, Mats
    Department of Electromagnetic Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Samuelsson, Carl
    Saab Aeronautics, Linköping, Sweden.
    Kangashaka Vallhagen, Bengt
    Saab Aeronautics, Linköping, Sweden.
    Shielding Effectiveness and HPM Vulnerability of Energy-Saving Windows and Window Panes2019In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 61, no 3, p. 870-877Article in journal (Refereed)
    Abstract [en]

    In this paper, we report results from shielding effectiveness measurements on energy-saving windows and individual, coated window panes of different generations, as well as results from high-power microwave irradiation on single panes. Shielding effectiveness was measured with two complementary methods: first, with near isotropic irradiation in nested reverberation chambers, and the other with irradiation at normal incidence in a semianechoic chamber. The measurements show that the construction of the energy conserving windows has a clear impact on how well they attenuate radio frequency signals. The more modern the window or pane, the higher is the shielding effectiveness. The high-power irradiation on coated panes showed that depending on the type of coating, hotspots can build up causing the coating to crack and, hence, deteriorate the shielding effectiveness. These results may serve as guidance when reviewing high-altitude electromagnetic pulse (EMP), high-power microwave, or intentional electromagnetic interference protection of critical infrastructures, and provide assistance in the work with reduction of compromising emanations.

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