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  • 1.
    Abdalla Mohamed Ahmed, Fayad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Energy Audit in Educational Buildings: Case study of Fridhemsskolan in Gävle2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The global share from buildings towards energy usage in residential and commercial buildings have been increasing constantly reaching between 20% to 40% in developed countries and has overtook the other major sectors: industrial and transportation. Energy demand reduction in the building sector is important for Sweden to achieve national energy aims for reduced energy use in the future.  For this reason, energy efficiency measures in buildings today is one of the main objective for energy policy towards 2020 goals.

     

    This project moves on the same path to find energy efficiency potential in Fridhemsskolan buildings in Gävle, Sweden by performing energy audit using IDA-ICE software to simulate energy performance for the buildings under study. In addition, measurements have been made on three of the school buildings named Hus 1, Hus 2 and Hus 3.

     

    The results include different energy efficiency retrofits on each building and economic analysis of these retrofits for each building individually and for the whole buildings together. The presented measures are reducing working hours of the ventilation system in Hus 2, change of CAV system with VAV system in (Hus 1 and Hus 2) and lights changing to LED, s efficient lights and building envelope improvement which includes walls and roof extra insulation and windows replacement.

     

    Replacement of the CAV system in Hus 1 and Hus 2 were not economically beneficial when considering their high cost compared to energy reduction that can be achieved by applying them. On the other hand, energy retrofits analysis showed that combination of the following energy efficiency measures is the most effective and profitable: extra insulation (walls and roof), windows replacement and lights change to LED in the three buildings. In addition to these measure is reducing running hours of the ventilation system in Hus 2.

     

    Implementation of the recommended energy efficiency measures will save 120, 737 kWh/ year of the district heating and 21, 962 kWh/year electricity consumption with capital investment of 417, 396 SEK and 98, 957 SEK/ year cost saving with payback period of 4.2 years. These figures represent 40.3% and 18.1% reduction in district heating and electricity energy use respectively.

     

    Since reducing working hours of ventilation system measure has no capital investment and have the highest figure of energy reduction it reduces payback period significantly. In case the amount of money saved by this measure doesn’t consider; payback period for the other measures which require capital investment will be 13.5 years and the energy saving in terms of cost will be 30, 874 SEK/ year. 

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  • 2.
    Abdalmunim, Rand
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Effektivisering av bygglovsprocessen gällande ändring av kulturhistoriskt värdefull bebyggelse: En fallstudie av ett miljonprogramsområde-Nya Nordostprojektet i Gävle2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En stor del av Sveriges bebyggelse har byggts mellan 1965 och 1974 eftersom det rådde stor bostadsbrist i Sverige. Regeringen beslutade att en miljon bostäder skulle uppföras under denna tid, det s.k. miljonprogrammet. Det byggdes bostäder i varierande former och storlekar för att bygga bort bostadsbristen. Storskaligheten och en stor grad av upprepning av identiska hus är kännetecken för miljonprogrammets bebyggelser. Nu är det dags att renovera dessa byggnader. I och med att dessa byggnader är av allmänt intresse då de speglar en del av Sveriges arkitekturhistoria ställer kommunerna vissa krav vid renovering av dem. Det kommunala företaget Gavlegårdarna i Gävle tar initiativ till att utveckla bygglovsprocessen för sådana bebyggelser. Detta görs för att reducera tiden för framställande av ett godkänt bygglov samt effektivisera och underlätta kommunikationen med kommunen under hela projektet. För att kunna bevara dessa byggnader i högsta möjliga mån har Gavlegårdarna utarbetat en effektiviseringsprocess genom att hyra in en extern bevarandeexpert för att fungera som en bro mellan företaget och kommunen samt för att kunna dela med sig av sina erfarenheter gällande bevarandet av det eventuella området. Dessutom har Gavlegårdarna låtit kommunen vara med från ett tidigt skede, d.v.s. redan från den första presentationen av förslaget. Därmed har kommunen fått vara med och medverka i förslaget, redan innan bygglovsansökan.

     

    Detta examensarbete tar upp konsekvenserna av de nya tillagda rutinerna och hur de har påverkat bygglovsansökningsprocessen för Nya Nordostprojektet. Genom att intervjua de inblandade aktörerna i det undersökta projektet har slutsatsen dragits att dessa rutiner har bidragit till att processen bedrivits mer effektivt jämfört med företagets tidigare projekt. Därutöver visar denna uppsats hur hyresgästerna har engagerat sig i det eventuella arbetet. Enkätundersökning har utförts för att kunna höra hyresgästernas åsikt.

     

    Det har visat sig att de nya rutinerna har effektiviserat tiden för bygglovsansöknings-processen. Tiden har förkortats jämförts med Gavlegårdarnas övriga projekt. Fördröjning i tid kostar företaget mer pengar. Dessutom har den förbättrade kommunikationen underlättat för båda parter att ta emot klagomål lättare och acceptera det. Det bidrar till att kommande problem kan lösas smidigare. Undersökningen har även visat att i projekt som Nya Nordost tas inte stor hänsyn till hyresgästernas åsikter, då byggherren redan är styrd från kommunen, vilket försvårar att flera kan vara med och välja. Ett annat resultat av denna undersökning var att de intervjuade personerna hade olika åsikter om bevarandet gällande Nordost. De flesta tyckte att Nordost ej var värt att bevara. Undersökningen visade även att hyresgästerna inte har engagerat sig lika mycket i bevarandet av gamla byggnader jämfört med att bo i ett modernare och nyrenoverat område.

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  • 3.
    Abeyrathna, Nuwan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. KTH.
    Design and Construction of a Supervisory Control and Data Acquisition System for full scale combustion test facility2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of major concerns in gas turbine industry is to reduce emissions.  Tow kind of approaches could be identified in the industry to reduce emissions, namely Primary Emission Reduction approach and Secondary Emission Reduction approach. The primary approach concerns emission prevention in combustion, while secondary approach is all about emission cleanup before releasing to the atmosphere.

    Combustion flame temperature highly influences on emissions specially NOx formation.  NOx emission is lower when the combustor operates close to lean flammability limit. Incorporating catalyst to combustor is one of methods to extend flammability limit.  Heat and Power Division at KTH-Royal Institute of Technology in Sweden has developed a test facility to test performances of catalyst in combustion.

    The combustion test facility available at Heat & Power Davison at KTH, consists of high pressure air compressor and air flow control system, air preheating unit and control system, fuel flow control system, combustor unit, and exhaust gas analyzer system. But lack of proper user interface to control and monitor the operation of the test facility through a computer work station was a major concern from experimenters.

    The purpose of the thesis work is to design and construction of supervisory control and data acquisition system for the full scale catalytic combustion test facility.  Labview 2012 is used as the main platform for implementing data acquisition and control system for the test facility. Thermocouples, pressure transducer signals, air flow meter signal are connected to Keithley 2701 data acquisition system and then connected to the computer. Fuel flow controllers are directly connected to the computer via serial port. Air flow control actuator signal is given through ADAM digital to analogue converter.

    Developed GUI is more convenient for users in terms of easy control of air flow, fuel flow and gas sampling probe systems, and monitoring of temperature, pressure measurements and exhaust gas species systems. And also GUI provides web interface to select correct conversion factor, and also to view live data recording. The developed GUI can be accessed through online to monitor the operation. 

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    EGI Thesis report_Nuwan Abeyrathna_Final
  • 4.
    Abeywardana, Asela Janaka
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Solar - Biomass hybrid system for process heat supply in medium scale hotels in Sri Lanka2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study aimed at evaluating and demonstrating the feasibility of using Concentrated Solar Thermal technology combined with biomass energy technology as a hybrid renewable energy system to supply the process heat requirements in small scale industries in Sri Lanka. Particularly, the focus was to apply the concept to the expanding hotel industry, for covering the thermal energy demand of a medium scale hotel.

    Solar modules utilize the rooftop area of the building to a valuable application. Linear Fresnel type of solar concentrator is selected considering the requirement of the application and the simplicity of fabrication and installation compared to other technologies. Subsequently, a wood-fired boiler is deployed as the steam generator as well as the balancing power source to recover the effects due to the seasonal variations in solar energy. Bioenergy, so far being the largest primary energy supply in the country, has a good potential for further growth in industrial applications like small hotels. 

    When a hotel with about 200-guests capacity and annual average occupancy of 65% is considered, the total annual CO2 saving is accounted as 207 tons compared with an entirely fossil fuel (diesel) fired boiler system. The annual operational cost saving is around $ 40,000 and the simple payback period is within 3-4 years. The proposed hybrid system can generate additional 26 employment opportunities in the proximity of the site location area.  

    This solar-biomass hybrid concept mitigates the weaknesses associated with these renewable technologies when employed separately. The system has been designed in such a way that the total heat demand of hot water and process steam supply is managed by renewable energy alone. It is thus a self-sustainable, non-conventional, renewable energy system. This concept can be stretched to other critical medium temperature applications like for example absorption refrigeration. The system is applicable to many other industries in the country where space requirement is available, solar irradiance is rich and a solid biomass supply is assured.    

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  • 5.
    Agebro, Andreas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Datormodellering av en värmelagrande betongväggs inverkan på det termiska klimatet i ett växthus2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report describes the building of a computer model that makes it possible to simulate the thermal climate in a greenhouse. The computer model is built on the physical theory of heat exchange that occur in a greenhouse, such as radiation and convective heat exchange. The model also includes the heat storage that is active in a greenhouse.

    The computer model is used to simulate the thermal climate in a greenhouse under three periods, winter, spring and summer. It also investigates which effect a concrete wall has on the thermal climate in a greenhouse. The purpose of putting a concrete wall in the greenhouse model is to investigate the possibility to store heat during the day and then use this heat when the temperature drops during the night.

    The result from the simulations shows that a concrete wall levels the big difference in temperature that normally occurs under a day in a greenhouse. It also shows that heat is stored in the concrete wall and during the night the wall temperature is higher than both the outdoor temperature and the greenhouse temperature. This makes the wall a source of heat during this time.

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  • 6.
    Aguirre Sánchez, Mikel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Air flow disturbance by moving objects at local exhaust ventilation2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The present thesis aims to study the effect of human movements on local exhaust ventilation.

    In its simplest terms, local exhaust ventilation is a system which has the function of extracting contaminated air situated close to the contaminant source, protecting a working person from exposure to hazardous substances by containing or capturing them locally, at the emission point. As an important security measure referred to terms of health, it is crucial for the healthiness of workers to control and prevent them from the exposure to vapour, mist, dust or other airborne contaminants. Additionally, to a lesser degree of significance, it can be stressed an expected increase in worker performance due to an improvement of the working conditions.

    There is an existing necessity for well-defined and appropriate methods to test the performance of local exhaust devices in order to reach standard efficiency values. The lack of an international standardization led to the realization of this study, which, ultimately, has the purpose of obtaining relevant results that can be utilized for future normalized test procedures.

    The study entails full scale experimental measurements that include air velocity measurements in 3 dimensions, a local exhaust ventilation device with circular hood and a flat flanged plate and a controlled generation of air turbulence through physical movements of a human-sized cylinder, simulating a walking person.

    The present study extends previous similar studies at the University of Gävle, where the controlled air turbulence was generated by a moving plate. After meaningful results obtained in that study, one of the considerations was to better simulate a walking person, by replacing the plate for a movable cylinder. The present study points at a larger similarity occurring with a cylinder than with a plate, as regards the air flow pattern produced by a real walking person.

    As in the previous study, the Percentage of Negative Velocities, PNV, has been used as the main measure of turbulence induced risk of contaminant spread. The PNV represents the fraction of the time when the flow is directed opposite to the suction air stream in front of the local exhaust hood. The obtained results conclude that the use of the cylinder as a moving object has been an improvement to simulate the effect of the movement of a human being on a relaxed walking pace.

    The present study was carried out in parallel with the thesis work by Leyre Catalán Ros, which complements this study by analyzing the effect of an added heated dummy, simulating a person seated in front of the local exhaust device.

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  • 7.
    Ahlund, Viktor
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energikartläggning av förskolan Smultronstället2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is an energy audit with recommended energy efficient solutions recommended made on a preschool in north Gävle. This preschool is administrated by Gavlefastigheter. In Sweden almost 40 % of Sweden’s energy supply goes to the housing and service sector. This means there is a lot of potential to save energy in this field. A good way to start saving energy in a building is to do an energy audit.This energy audit is made from blueprints of the building, real measurements, standard values, assumptions, and literature.The school has a calculated energy use of 1239 MWh per year; this is divided on ventilation, transmission losses and hot tap water. A calculation with energy efficient solutions makes a total of 612 MWh or 49, 4 % in saved energy. The energy efficient savings calculated are new windows, additional insulation and changed ventilation. To only change the ventilation made for an energy saving of 522 MWh which is 42, 1 % from the total energy use in the building. To change the ventilation to an FTX-system is the recommended change to be made.

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  • 8.
    Ahmed, Basem
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Investigation of energy retrofits of a multi-family building by using IDA Simulation Software2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Energy simulation in building sector was an important issue which can eliminate energy use and improve energy efficiency. The building, which is located at Ringvägen 18 in Ljusdal community in Sweden, was chosen to be the main mission of this research and it was one of eleven objects which were involved in EKG project. First step was to create the model and simulate it to reach heating value of 117 MWh which was reached by EKG project. After getting validation value, many renovations were implemented and the heating value was reduced by 58.7% and the heating demand by 55.2%. Improving of energy use through prefabrication gave reduction of heating value of 70.4% and heating demand of 65.8%

    The LCC part was important issue because it gave clear vision and judgment about the economic and investment issue. The acceptability of the investment decision was decided by 198 answers which were responsible to judge if the investments were good or not. There were 22 types of different renovation and every type included 9 cases which depended on interesting rate and energy price factors. The result was 198 answers which were divided to 100 answers as “YES” for good investment and 98 answers as “NO” for good investment.

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  • 9.
    Ahmed, Dolovan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Fadul, Mohammed Erik Jamal
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Utsläpp från svenska reningsverk till Östersjön: Granskning av Henriksdals reningsverk, Ryaverket, Sjölunda reningsverk, Kungssängsverket och Duvbackens reningsverk2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    From domestic and industrial waste water will have to be cleaned before it can be released into lakes and streams again. This purification takes place through various stages of treatment plants. Wastewater contains many substances that are harmful to the environment as well as human and animal health, so it is important that the purification that is done is done in an efficient and thoughtful manner. The steps that are common in Swedish cleaning plants are mechanical, biological and chemical purification. These purification steps ensure that larger particles do not come out to the open water, convert nitrogen into nitrogen through the activation process, and that by chemical treatment, the emission of phosphorus is reduced. All of these purification steps can be designed differently and vary from purification plants to purification plants. Therefore, the degree of purification and emissions can distinguish between different treatment plants. Because there are many factors involved in the processes at Swedish waste treatment plants, it is important to carry out annual audits to detect problems that can lead to environmental damage.If cleaning does not work, exercise can increase in lakes and seas, which causes people and animals to suffer. Bottom dead and acid deficiency are already a major problem for the Baltic Sea. In order to reduce the negative environmental effects, emissions of nutrients are drastically reduced. This concerns the release of nutrients from all countries around the Baltic Sea.This study focuses on nitrogen and phosphorus purification from 5 wastewater treatment plants, Henriksdal's purification plant (Stockholm), Ryaverket (Gothenburg), Sjölunda purification plant (Malmö), Kungssängsverket (Uppsala) and Duvbacken purification plant (Gävle). Information about its activities has been obtained through interviews and works own reports.The purification plants use different technical solutions, and all treatment plants meet today's requirements for purification. The biggest difference is the degree of nitrogen purification. All wastewater treatment plants have a history of changes in technical solutions to improve treatment. Cleaning wastewater from households and industries costs a lot of money for the treatment plants, so it's always a challenge for the wastewater treatment plants to clean the water in the best possible way without costing too much.It is expected that the cleaning requirements will be tightened and all treatment plants should continue to develop to increase efficiency. Current purification requirements are designed to suit the recipient's sensitivity. If the EU's idea of ​​the same degree of purification across the country is transformed into requirements, Duvbacken will need to significantly improve the nitrogen treatment at the waste water treatment plant.

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  • 10.
    Akander, Jan
    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.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Department of Management and Engineering, Division of Energy Systems, Linköping University.
    Assessing the Myths on Energy Efficiency When Retrofitting Multifamily Buildings in a Northern Region2017In: Sustainable High Rise Buildings in Urban Zones: Advantages, Challenges, and Global Case Studies / [ed] Ali Sayigh, Cham: Springer Publishing Company, 2017, 1, p. 139-161Chapter in book (Other academic)
    Abstract [en]

    In the light of EU’s requirements to achieve a major cut in energy use by 2050, Sweden has the same target. The built environment must by 2020 reduce energy use by 20 and 50 % by 2050. The size of the future building stock will naturally increase and regardless of how energy efficient future buildings will be, the energy performance of the old stock must be improved in order to reach those goals. In major renovation projects involving multifamily buildings in large residential areas in the cities, 50 % reduction can be achieved. This is cost-effective and profitable even if the rent is increased.

    Gävleborg is a sparse region in the North, with few cities. Multifamily buildings are generally much smaller than in large cities and owners are reluctant to impose changes that increase rents due to the housing situation in the region. In consequence, the Regional Council and the University of Gävle set out to assess the potential and feasibility of reducing energy use and carbon dioxide emissions in this region’s multifamily buildings. Eleven real buildings were investigated, each having various ownership forms, different technical attributes and heating sources. Energy audits and measurements were conducted to assess the condition of each building. Performances of the buildings and proposed improvements were simulated with building energy simulation programs, whilst life cycle cost analyses were conducted to study viability. Carbon dioxide emission (CO2) reductions were estimated for each improvement.

    Based on the results, a concluding discussion is made on whether or not some myths on energy use and retrofitting are true. The following is concluded: It is possible to reach a 50 % reduction, but it is not economical with the costs involved and with today’s energy prices and moderate price increase over time.

    Retrofitting or improvements made in the building’s services systems (HVAC) are more economical than actions taken to improve performance of building by constructions. HVAC improvements give about 20 % reduction in energy use. However, mechanical ventilation systems with heat recuperation are not economical, though these may or may not substantially reduce use of thermal energy.

    Solar energy is, despite the latitude of the region, economically viable—especially PV solar energy. Photovoltaic panels (PVs) are becoming viable—the combination of PVs and district heating is beneficial since saving electricity is more important than thermal energy in district-heated areas.

  • 11.
    Akander, Jan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Morberg, Åsa
    University of Gävle, Faculty of Education and Business Studies, Department of Educational sciences, Educational science.
    Sustainability of world heritage: who inherits the ownership of decorated farmhouses of Hälsingland?2017In: A Good Life for All: Essays on sustainability celebrating 60 years of making life better / [ed] Fagerström, Arne and Cunningham, Gary M., Mjölby: Atremi AB , 2017, 1, p. 139-161Chapter in book (Other academic)
    Abstract [en]

    This chapter discusses sustainability of Sweden’s most recent World Heritage (WH) site, the Decorated Farmhouses of Hälsingland. A general overview presents what WH is, why it is special and why it should be preserved for future generations. The views of WH farm owners on managing a WH site and how they feel about the task have been assessed. WH must be preserved for future generations and it is necessary for the farms to interact sustainably with their local communities. Most WH farms are privately owned and have been within the same family for centuries. Will this continue in the future or are there problems with succession?

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  • 12.
    Al hamdany, Yarub
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Simulering och energieffektivisering för en kontorsbyggnad iForsmark2018Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    The society changes rapidly and is heavily dependent on energy. The Energy usage in buildings account for about 40% of total Sweden's energy usage, where energy is used by buildings for electricity, cooling and heating. Therefore, energy is an important issue in today's society from an energy use approach to stop the global warming. In this work, a survey was carried out by an office building in Forsmark Kraftgrupp AB to find out about energy use and create a basis for energy-saving measures. The IDA ICE 4.7.1 program was used to simulate the building's energy use by creating a base model of the building. After that, the base model has been compared with different energy efficiency measures to check where the biggest and least energy saving potentials occur. The result shows that the total energy use in the office building is 198 125 kWh / year. The simulations show that energy efficiency measures could reduce energy use in the building by 81 962 kWh / year, which corresponds to 41.4% of the total energy use. Time control of ventilation systems gives the largest energy savings of 51, 2 kWh / m2, year.

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    examensarbete-11
  • 13.
    Alcheikh, Ahmad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Advantages and Challenges of Hemp Biodiesel Production: A comparison of Hemp vs. Other Crops Commonly used for biodiesel production2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Reducing reliance on a fossil fuel is a major challenge to many advanced and developing economies. This is due to the fact that fossil fuel, a finite resource, is depleting at a rapid rate with increasing demand. Additionally, the burning of fossil fuel is responsible for the current climate change, as a result of produced greenhouse gas emissions. Lastly, developing alternative renewable fuels improves energy security and decreases vulnerability of fuel supply. This thesis work explores the advantages and challenges of hemp biodiesel production. The aim of this research is to present a comprehenive evaluation of these advantages and disadvantages in the way of large-scale production of biodiesel produced from hemp oil. The thesis work relies on relavent research paper in the field and reports from the industry. Industrial hemp, a variant of the Cannabis Sativa plant (Cannabis Sativa Linn), is an important industrial and nutritional crop. Hemp seed oil can be used to produce biodiesel though the process of transesterification. Oil from hemp seeds presents a viable feedstock option for biodiesel production. Hemp provides a competitively high yield compared to similar crops. Biodiesel from hemp seed oil exhibits superior fuel quality with the exception of the kinetic viscosity and oxidation stability parameters, which can be improved with the introduction of chemical additives. Hemp remains a “niche” crop in the food supply chain, which makes it prohibitively expensive a primary feedstock in biodiesel production. Legal and perception challenges remain a major challenge in the way of wide-scale hemp biodiesel production. 

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    Master Thesis
  • 14.
    Almquist, Olivia
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Testrutin för dricksvattenfilter för upp till 50 P.E.: ett förslag på tillvägagångssätt2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is, with the laws regarding drinking water filter up to 50 P.E. as the basis, to create a routine for how the tests should be for the filters in a test-bed facility. How will a common test routine be designed for better assessment of drinking water filters today?

     

    The thesis is based a literature study in the form of both websites and legislations. The information have been retrieved from the websides of relevant companies such as, the National Food Agency (NFA) and similar organizations working on drinking water issues. While the legislations have been taken from, for example, National Public Investigation and/or likewise. Several of the references that are used have backing from several other sources which should mean that the information is reliable. The legislation is the starting point for a functioning Sweden which should mean that it is reliable.

     

    It has also been conducted a survey through email, where approximately 50 companies in the drinking water filter industry were asked what they think about various statements. The questions were based on an already developed proposals for a test routine that the author developed earlier. This method was chosen because it is difficult to get a clear picture of what the market is interested in examining without asking them.

     

    Water in its raw form H2O does not taste or smells anything. It can, however, change when it is in contact with other materials. This is because water is highly soluble and thus dissolves other substances. Therefore it is important that materials used in drinking water treatment should be safe where the consumer might otherwise ingest unhealthy substances through drinking water. Building and Planning Agency together with the National Food Administration and the Swedish Chemicals Agency will design a platform where stakeholders can easily find information regarding approved materials in contact with drinking water.

     

    There are approximately 1.2 million households in Sweden (both permanenta- and leisure accommodations) who receive their drinking water from private well. It is therefore the well owner's responsibility to make sure that the drinking water has a good quality. There is no legislation on the control of its own drinking water. The recommendation suggest sampling every three years on the well if it only supplies a household but every year if there are more than one household that are supplied. Approximately 1/5 of all drinking water is estimated to be unfit.

     

    There are many different types of filters and methods which can make it confusing and difficult for people to choose the right one. Some of those types are ion exchange, activated carbon, reverse osmosis, sand filters, air filters, cartridge filters, UV light and scale filter. The filters have different characteristics and work in different ways. According to WHO guidelines for safe drinking water. Many substances are not regulated with any limits as long as the WHO does not consider that the concentration of that substance will be sufficient enough to affect people negatively. Examples of these are pH, iron chloride, manganese and potassium. Although EU has a list of safe drinking water which NFA base their limits on.

     

    The proposed test routine became somewhat shorter and less strict than the routine as it was based on. It is reported in Appendix 2 together with the questionnaire sent out to businesses to find out what they thought about the proposal on the test routine. Drinking water filters should be tested in 32 weeks during which a power failure will be simulated. It is even recommended that the capability of the filter should be tested at high flow and no flow for a certain number of hours during each week.

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  • 15.
    Al-Mulla, Tiba
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Jämförelsestudier mellan olika typer av korslimmat träbjälklag:: Undersökning av konsekvenser vid ändring från betong- till korslimmat trä- bjälklag i ett flervåningshus2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Timber is one of the most common materials that had been use for a long time. The need for new buildings will affect the climate negatively, that is why it’s necessarily to find new ways to build quickly and sustainably. Cross-laminated timber (CLT) product came in the 1990- century. The material was developed to be used in high residential wood constructions buildings.

    The material considered to have good properties compared with other types of wood material, some of the studies showed the possibilities of building high residential with the CLT material. Such high rises buildings work best when CLT wood constructions combined with other materials, which called, Composite constructions.

    Case study preformed theoretically in Fullriggaren building in Alderholmen in Gävle city, the building have 14 floors and about 40 m high. With the purpose of trying to investigate the consequences that occur when the concrete floor slabs were replaces  with CLT wood floor slabs, taking into account the rules and standards for fire safety, acoustics, oscillations and vibrations. In order to achieve this and to determine the most suitable alternatives, the different types of CLT-wood floor slabs was compared.

    The building studied in its design and execution, and a simpler model created in Revit 2018. The challenge was that the building has a long span of maximum 10 m. The different types of CLT floor slabs which compared in the study was, CLT timber joist slaps, flat floor slab and CLT wood floor slabs in combination with steel hat beams and other beam steel types. Each type of floor slabs had its advantages and disadvantages, but the results and studies showed that timber and concrete composite floor slab combined with steel hat beams are the best possible options for the construction in Fullriggaren building, where the floor slab height is the shortest compared to other CLT wood floor types. With the chosen floor slab, the problem of vibration and oscillations will minimize. When using such a floor slab, the building height will increase, which means in this case, removing an entire floor from the building.

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    fulltext
  • 16.
    Alonso Lozano, Alvaro
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Coal gasification in entrained flow gasifiers simulation & comparison2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
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    Coal gasification
  • 17.
    Al-Saour Rafie, Mais
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Farhad, Tafan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Tillgänglighet och användbarhet i nybyggnation: En fallstudie - Bostadslägenheter på Gävle Strand Etapp2 - Gavlegårdarna2014Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Human beings are always considered to be the starting point for various construction projects; their needs and interests should always be the center of each successful design. At the same time, considerations should be given to activities and surrounding environment to ensure that buildings can be both accessible and usable.

    The accessibility and usability requirements for constructions were introduced in 1977 by the National Housing Board and have evolved since then. The requirements are still developing to achieve homes that are accessible and useable, especially for people with disabilities. They have also been tightened in particular concerning the design of new construction and alteration of buildings.

    Gavlegårdarna have, in 2012, built new residential apartments with high accessibility standards. The apartments in Gävle Strand, Stage 2 are located in an area next to the sea and offer new opportunities for a modern way of living. Considering the new residential area of Gävle Strand, this case study focuses on the accessibility standards concerning three categories of disabilities: limited mobility, limited vision and limited hearing. The case study examines three selected apartments with different living area. The purpose of the case study is to assess the accessibility and usability of the apartments. This is done through an inventory using a wheelchair, taking a walking tour while blindfolded and using a cane. Before the assessment of the apartments' requirements, an inventory list of respective apartments was prepared. The list is based on regulations, laws and recommendations from Building Regulations and Swedish Standard.

    The results of the case study categorize the apartments in two levels: normal- and high level accessibility. Spaces and details that are considered to have high accessibility have externally contrast markings including the entrances and stairways. Inside, the apartments are well planned for enhanced usability and there are spacious areas where a wheelchair can move without any difficulty.

    The conclusion shows that all apartments meet the requirements at normal level which is the minimum level of accessibility and usability. Despite the general assessment of the apartments’ well-planned design, the study finds flaws in the form of a cramped bathrooms and high thresholds to the balcony doors. Finally, in order to achieve high availability the case study presents improvements and measures that need to be changed to the presented deficiencies.

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    Tillgänglighet och användbarhet i nybyggnation
  • 18.
    Amarawardhana, Kumudu Nanditilaka
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Modeling of energy utilization of tourism industry to predict the future energy demand to showcase Sri Lanka - The ‘Miracle of Asia’2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Tourism industry in Sri Lanka shares a substantial amount of GDP (Gross Domestic Product) and predicts an immense expansion within a short time frame. Owing to its energy intensiveness and competitiveness, a scrutiny in the energy utilization and the related impact on the environment is crucial. Furthermore, trend towards ecotourism forces the requirement of foreseeing a green energy supply to meet the ever rising demand.   In this study, utilization of energy in the graded hotels in the country was modeled through LEAP (Long Range Energy Alternatives Planning System) software to predict the future energy demand. Monthly energy consumption data for three consecutive years for a sample of hotels covering classified and unclassified hotel establishments were used for modeling. Four scenarios were then analyzed based on the baseline scenario representing the country’s tourism industry profile of year 2010.  It is shown that the energy intensiveness of the tourism industry will be overwhelming unless the DSM (Demand Side Management) tools are properly amalgamated for mitigation. Further the results of the study revealed that the existing electricity generation plan does not accommodate fuel diversification and energy mix, and needs revisions to induct renewable sources for greening energy supply of the country. The study provides an insight in identifying socially acceptable policy scenarios in energy supply and use of the tourism industry.

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    Amarawardhana Kumudu EGI-2014-031MSC
  • 19.
    Ameen, Arman
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Efficient Cooling with multiple impinging jets: Obtaining boundary condition and verification for a CFD model2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Saving energy and optimizing industrial processes are major priorities for companies around the world. In this study the cooling process (with air) of large rollers are examined. The result of these examinations are used to create a computational fluid dynamic model. These examination consists of geometry, volume flows, velocities, velocity profiles, temperature and pressure. A complication in the measurements occurred due to the nonsymmetrical installation of the nozzles in the cooling setup. The results highlights how this nonsymmetrical installation affects the cooling. Multiple methods were used to carry out this work, and some additional side project were implemented. The results in this thesis is not enough to create a CFD model and further work have to be carried out in the future.

  • 20.
    Ameen, Arman
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energianalys och energieffektivisering av en förskola: Söderskolan (Slottets förskola) i Gävle, simulering utförd genom IDA ICE 4.612014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bostad- och servicesektorn står för 38 % av Sveriges totala energianvändning. Av det här står bostäder och lokaler för 90 % av energianvändningen och nästan 60 % av det går till att värma upp byggnaderna och till varmvatten. Därför är det viktig att börja titta på den här sektorn och se om det finns möjlighet att spara på energianvändningen. I den här studien har en kartläggning gjorts av en gammal skolbyggnad för att kunna skapa ett underlag för energieffektiviseringsåtgärder. Genom att använda simuleringsprogrammet IDA ICE 4.61 har man skapat en basmodell av byggnaden som då används som simuleringsbas. Basmodellen har jämförts med fjärrvärmekostnader för att kunna verifieras. Därefter har man lagt in energieffektiviserar och tittat på vilka besparingar man har kommit fram till. Resultatet av den här studien visade att i den här byggnaden så är den mest effektiva åtgärden isolering av taket till vinden.

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    Examensarbete_Arman
  • 21.
    Amiot, Victor
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Torung, Rikard
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Oliksidig krympning i betong2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Concrete is one of the most commonly used building materials in foundation construction. Concrete is highly resistant to external stresses and hence makes it a very useful material in many different situations. However, there are problems that can arise with the use of concrete. One of the more common is cracking. There are several reasons why this might occur, for example, external impact, creep and moist-related movements. The concrete slab is one of the elements that often encounter this problem. Since concrete slabs are frequently used as foundation, it is of great interest to find solutions for this matter. In order to do that, the causes are needed to be specified more clearly. This study investigated experimentally how a concrete slab reacts when differences in humidity exposing the top and bottom after curing period, and if this may contribute to sufficient deformation to cause cracking. Six specimens were made and observed where three where exposed to a moisture content of 100% on the bottom. The remaining three samples have been placed in dry conditions in order to make a comparison possible. A relative humidity of 25% was measured in the surrounding air. The experiment showed clear differences in deformation between the two situations. The samples exposed to differential humidity exhibited sufficient stresses to cause cracking seen from the moment that occurred in the concrete. This shows that different prevailing humidity on the top and bottom of a slab can create sufficient stress to cause cracking.

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    Oliksidig krympning i betong
  • 22.
    Amiri, Shahnaz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Economic and Environmental Benefits of CHP-based District Heating Systems in Sweden2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Future energy systems and thus the climate are affected by many factors, such as energy resources, energy demand, energy policy and the choice of energy technologies. Energy systems of the future are facing three main challenges; the steady growth of global energy demand, the energy resource depletion, as well as the increasing emissions of carbon dioxide (CO2) and other greenhouse gases and their impact on climate change. To meet the mentioned challenges with sustainability in mind, actions that increase energy efficiency and choosing an energy-efficient energy system which is cost efficient will be essential. Combined heat and power (CHP) plants and district heating and cooling could contribute greatly to increased system efficiency by using energy otherwise wasted.

    The aim of this study is to increase the understanding of how CHP-based district heating and cooling systems using different primary energy sources can contribute to more cost-efficient energy systems, which reduce global CO2 emissions, and to highlight the impact of some important parameters and measures on Swedish municipal district heating systems. An important assumption in this study is the estimation of CO2 emissions from electricity production, which is based on marginal electricity perspectives. In the short term, the marginal electricity is assumed to come from coal-fired condensing power plants while in the long term it consists of electricity produced by natural gas-fired combined cycle condensing power plants. This means that the local electricity production will replace the marginal electricity production. The underlying assumption is an ideal fully deregulated European electricity market where trade barriers are removed and there are no restrictions on transfer capacity.

    The results show that electricity generation in CHP plants, particularly in higher efficiency combined steam and gas turbine heat and power plants using natural gas, can reduce the global environmental impact of energy usage to a great extent. The results confirm, through the scenarios presented in this study, that waste as a fuel in CHP-based district heating systems is fully utilised since it has the lowest operational costs. The results also show how implementation of a biogas-based CHP plant in a biogas system contributes to an efficient system, as well as lowering both CO2 emissions and system costs. The results show that replacing electricity-driven (e.g. compression) cooling by heat-driven cooling using district heating (e.g. absorption chillers) in a CHP system is a cost-effective and climate friendly technology as electricity consumption is reduced while at the same time the electricity generation will be increased. The results of the study also show that there is potential to expand district heating systems to areas with lower heat density, with both environmental and economic benefits for the district heating companies.

    The results reveal that the operation of a studied CHP-based district heating system with an imposed emission limit is very sensitive to the way CO2 emissions are accounted, i.e., local CO2 emissions or emissions from marginal electricity production. The results show how the electricity production increases in the marginal case compared with the local one in order to reduce global CO2 emissions. The results also revealed that not only electricity and fuel prices but also policy instruments are important factors in promoting CHP-based district heating and cooling systems. The use of electricity certificates has a large influence for the introduction of biogas-based cogeneration. Another conclusion from the modelling is that present Swedish policy instruments are strong incentives for cogeneration with similar impact as applying external costs.

  • 23.
    Amiri, Shahnaz
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Henning, Dag
    Optensys Energianalys, Linköping, Sweden .
    Karlsson, Björn G.
    Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden .
    Simulation and introduction of a CHP plant in a Swedish biogas system2013In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 49, p. 242-249Article in journal (Refereed)
    Abstract [en]

    The objectives of this study are to present a model for biogas production systems to help achieve a more cost-effective system, and to analyse the conditions for connecting combined heat and power (CHP) plants to the biogas system. The European electricity market is assumed to be fully deregulated. The relation between connection of CHP. increased electricity and heat production, electricity prices, and electricity certificate trading is investigated. A cost-minimising linear programming model (MODEST) is used. MODEST has been applied to many energy systems, but this is the first time the model has been used for biogas production. The new model, which is the main result of this work, can be used for operational optimisation and evaluating economic consequences of future changes in the biogas system. The results from the case study and sensitivity analysis show that the model is reliable and can be used for strategic planning. The results show that implementation of a biogas-based CHP plant result in an electricity power production of approximately 39 GW h annually. Reduced system costs provide a profitability of 46 MSEK/year if electricity and heat prices increase by 100% and electricity certificate prices increase by 50%. CO2 emission reductions up to 32,000 ton/year can be achieved if generated electricity displaces coal-fired condensing power.

  • 24.
    Amiri, Shahnaz
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering.
    Possibilities and consequences of deregulation of the European electricity market for connection of heat sparse areas to district heating systems2010In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, no 7, p. 2401-2410Article in journal (Refereed)
    Abstract [en]

    The objective of the study is to analyse the conditions for connection of residential buildings in heat sparse areas to district heating systems in order to increase electricity production in municipal combined heat and power plants. The European electricity market has been assumed to be fully deregulated. The relation between connection of heat sparse areas, increased electricity and heat production as well as electricity prices, fuel prices and emissions rights is investigated. The results of the study show that there is potential to expand the district heating market to areas with lower heat concentrations in the cities of Gavle, Sandviken and Borlange in Sweden, with both economic and environmental benefits. The expansion provides a substantial heat demand of approximately 181 GWh/year, which results in an electricity power production of approximately 43 GWh/year. Since the detached and stand-alone houses in the studied heat sparse areas have been heated either by oil boiler or by direct electricity, connection to district heating also provides a substantial reduction in emissions of CO(2). The largest reductions in CO(2) emissions are found to be 211 ktonnes/year assuming coal-fired condensing power as marginal electricity production. Connection of heat sparse areas to district heating decrease the system costs and provide a profitability by approximately 22 million EURO/year for the studied municipalities if the price of electricity is at a European level, i.e. 110 EURO/MWh. Sensitivity analysis shows, among other things, that a strong relation exists between the price of electricity and the profitability of connecting heat sparse areas to district heating systems.

  • 25.
    Amiri, Shahnaz
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Weinberger, Gottfried
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Increased cogeneration of renewable electricity through energy cooperation in a Swedish district heating system - A case study2018In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 116, p. 866-877Article in journal (Refereed)
    Abstract [en]

    The present study of the district heating (DH) system in the city of Kisa, Sweden, shows how, through energy cooperation with a nearby sawmill and paper mill, a local energy company contributes to energy-efficient DH and cost-effective utilization of a new biofuel combined heat and power (CHP) plant. Cases of stand-alone and integrated energy systems are optimized with the linear program MODEST. The European power market is assumed to be fully deregulated. The results show clear advantages for the energy company to cooperate with these industries to produce heat for DH and process steam for industry. The cooperating industries gain advantages from heat and/or biofuel by-product supply as well. The opening to use a biofuel CHP plant for combined heat supply results in cogenerated electricity of almost 29 GWh/a with an increased biofuel use of 13 GWh/a, zero fuel oil use and CO2 emission reductions of 25,800 tons CO2/a with coal-condensing power plant on the margin and biofuel as limited resource. The total system cost decreases by −2.18 MEUR/a through extended cooperation and renewable electricity sales. The sensitivity analysis shows that the profitability of investing in a biofuel CHP plant increases with higher electricity and electricity certificate prices.

  • 26.
    Amunarriz Ollokiegi, Endika
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Electric heated windows: thermal comfort and energy use aspects2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
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    FINAL REPORT
  • 27.
    Anastasopoulou, Kyriaki
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Creation of a Low Energy Building with the help of Energy Simulation2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this Thesis Project, the creation of a Low Energy building was examined in order to investigate how complex was to select the suitable parameters and systems of the dwelling, aiming to achieve the lowest possible energy consumption in one year period. All the technologies implemented into the system intended to be as energy efficient and profitable as possible. Another objective of this study was also to present the potential of the system to produce a part of the consumed energy, through renewable energy sources, approaching by this way also the standards of a Zero Energy Building. Firstly, the floor plan of the 150 m2 detached house, was drawn in the designing program AutoCAD. In continuation, this 2D floor plan was imported into the simulation program as well as all the initial input data so as for the Base model of the building to be created For the analysis of the building, the Simulation Program IDA ICE 4.7 was used. Gradually, alternations and adjustments were made into the Base model. Different models were created planning to analyze their results and conclude to the proper solution. All the simulations run for one year time period in order to present the total energy usage, system’s losses and demands in each case. In addition, as for the current study, the location of the construction was Athens, all building’s characteristics were chosen to comply with the Greek Regulation for Low Energy Buildings. Finally, through the procedure followed after having accomplished a series of simulations, the final annually energy demands managed to be within the required limits.

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    fulltext
  • 28.
    Andersen, Niklas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Wind Turbine End of Life: Characterisation of Waste Material2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wind power is growing fast all over the world, and in Sweden alone thousands of turbines has been installed the last few decades. Although the number of decommissioned turbines so far is very low, the rapid installation rate indicates that a similar rapid decommissioning rate is to be expected shortly. If the waste material from these turbines is not handled sustainably the whole concept of wind power as a clean energy alternative is challenged.

    This study aims to present an accurate estimate of the amounts of waste material that will be generated from wind turbines in Sweden during the coming decades, allowing the waste management industry to plan for this and by extension prevent unnecessary energy losses through imperfect waste treatment. It should also present helpful information on how problematic waste can be reduced or avoided.

    VindStat’s annual report, presenting installation date and other relevant data for most installed turbines in Sweden, has been used as the base for the calculations. Information on material composition in different types and sizes of wind turbines has been extracted from various life cycle assessments, and by using the available parameters in the data base each turbine has been assigned a specific amount of steel, iron, copper, aluminum, blade material and electronics. An average life time of 20 years has been assumed, based on prior research and comparison with empiric data, and the material of each turbine is therefore seen as generated waste 20 years after installation date.

    To calculate the amount of waste material from replacing faulty components, empiric data over replacement rates in further developed markets has been combined with a prognosis over future development of installed wind capacity in Sweden based on a method described by prior research. As no sufficient way to predict how the future second hand market for turbines and components has been found, three different possible scenarios have been investigated to see how this may affect waste amounts.

    The results show that annual waste will grow slowly at about 12 % increase per year until around 2026, and then the average increase is 41 % per year until 2034. By then, annual waste amounts are estimated to have reached 237 600 tonne steel and iron (16 % of currently recycled amounts), 2 300 tonne aluminium (4 %), 3 300 tonne copper (5 %), 343 tonne electronics (<1 %) and 28 100 tonne blade material. There is no industrial scale recycling method for commonly used blade materials, and a high strength steel developed by Sandvik is proposed as a fully recyclable material to consider for further research. A well-functioning second hand market is shown to possibly have a major impact on waste amounts, at least in postponing it until better recycling systems are in place.

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    Wind turbines end-of-life - Characterisation of Waste Material
  • 29.
    Andersen, Niklas
    et al.
    Energi Funktion Komfort Skandinavien AB, Nacka, Sweden.
    Eriksson, Ola
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Hillman, Karl
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Wallhagen, Marita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Wind turbines’ end-of-life: Quantification and characterisation of future waste materials on a national level2016In: Energies, E-ISSN 1996-1073, Vol. 9, no 12, article id 999Article in journal (Refereed)
    Abstract [en]

    Globally, wind power is growing fast and in Sweden alone more than 3000 turbines have been installed since the mid-1990s. Although the number of decommissioned turbines so far is few, the high installation rate suggests that a similarly high decommissioning rate can be expected at some point in the future. If the waste material from these turbines is not handled sustainably the whole concept of wind power as a clean energy alternative is challenged. This study presents a generally applicable method and quantification based on statistics of the waste amounts from wind turbines in Sweden. The expected annual mean growth is 12% until 2026, followed by a mean increase of 41% until 2034. By then, annual waste amounts are estimated to 240,000 tonnes steel and iron (16% of currently recycled materials), 2300 tonnes aluminium (4%), 3300 tonnes copper (5%), 340 tonnes electronics (<1%) and 28,000 tonnes blade materials (barely recycled today). Three studied scenarios suggest that a well-functioning market for re-use may postpone the effects of these waste amounts until improved recycling systems are in place.

  • 30.
    Andersson, Christine
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Linderdahl, Sofia
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Ett förslag till arbetsmiljöplan för underhållsarbete inom bygg: en förenkling av rutiner för arbetsmiljöarbetet2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    According to the Swedish Work Environment Authority (Arbetsmiljöverket), accidents among construction workers occur twice as often as other workers. In 2015 the construction industry had over three thousand work accidents resulting in sick leave, which corresponded to eleven percent of Swedens total reported work accidents with sick leave. Considering what a worker in the building and construction industry expose themselves to in their daily work, it is obvious that focus must be towards safety.

    This study has been carried out on the building department for maintenance work at BillerudKorsnäs Gävle Bruk. At the company, there is a need for improving the establishment of safety and health plans within the existing working environment work. The aim and objective of the study is to create a draft template for the safety and health plan that is user friendly and includes the 13 works with special risks according to AFS 1999:3. Hopefully the template will contribute to a simplification of existing procedures in the construction working environment planning, lead to increased safety on site and fewer work accidents.

    To receive a better understanding of the viewpoint of BillerudKorsnäs Gävle Bruks construction workers regarding working environment and risks on site, semi-structured interviews were conducted and together with statistics on accidents and incidents, served as the studies results. In addition, a literature review has been conducted to provide an overview of previous studies in the field.

    The importance in carrying out risk assessments has been confirmed through interviews and becomes more evident as the conditions in the daily construction work varies in large proportion. Every work situation and risk is unique, therefore a risk assessment can not only consist of the 13 works with special risks. The interviews have confirmed the need for a simplification and improvement in the process of establishing a safety and health plan. A template for the safety and health plan should include how the work environment shall be conducted such as general information about the work and a risk assessment.

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    Examensarbete 2016 Sofia och Christine
  • 31.
    Andersson, Daniel
    et al.
    Radarbolaget.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Ottoson, Patrik
    Radarbolaget.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Radar Images of Leaks in Building Elements2015In: Energy Procedia, ISSN 1876-6102, Vol. 78, p. 1726-1731Article in journal (Refereed)
    Abstract [en]

    Through leakage in the building envelope there is a penetration of air, water vapor and particles. The degree of leakage of air can be quantified by existing methods. However, the location of adventitious openings is often not known. In order to overcome the limitations in existing methods, a non-contact and non-destructive method based on ultra-wide bandwidth radar technology is suggested. A test-bed is designed that can measure with different polarization to be able to detect flaws in different directions. Initial measurements shows promising results for further development of the method of using radar images to find leaks in building elements.

  • 32.
    Andersson, David
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Olsson, Philip
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Hur kan en skola med högre energianvändning än det svenska genomsnittet energieffektiviseras?: Energikartläggning2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The European Union as a whole is one of the largest energy users and has one of the world's largest greenhouse gas emissions. To reduce global warming, targets have been set to ensure that the average temperature on the earth does not increase more than 2 degrees since the pre-industrial time. Nearly 40% of Sweden's total energy use comes from the building and services sector which in context with that the 2020 targets approaching contributes to the increased need of higher energy efficiency of buildings. Energy audits is a tool for determining what has the greatest potential for saving energy before efficiency measures occurs.

    The thesis includes an energy audit of Trödje primary and middle school, administered by Gavlefastigheter. The study was performed using IDA Indoor Climate and Energy simulation tool. IDA ICE was used to modulate the existing building where all data for the school was included. The vision of the thesis is to investigate how much energy which is possible to save through energy saving measures and which action that is most effective.

    The potential energy saving in the school is high, the school uses 42.6 kWh/m2year more than the average for Gavlefastigheter schools, which corresponds to 21 %. The results show that the complexity of the school and the reconstruction, also called the paviljong, are a major factor in the high energy consumption. The school's energy use has a potential to decrease by 17 %, which did not correspond to the 25 % target set for the work. The work shows that the greatest savings potential exists through the exchange of windows and heat exchangers in the ventilation system, but also that the measures that are assumed to give the greatest savings are not always the most effective.

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  • 33.
    Andersson, Erik
    et al.
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden .
    Barthel, Stephan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering. Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden.
    Memory carriers and stewardship of metropolitan landscapes2016In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 70, p. 606-614Article in journal (Refereed)
    Abstract [en]

    History matters, and can be an active and dynamic component in the present. We explore social-ecological memory as way to diagnose and engage with urban green space performance and resilience. Rapidly changing cities pose a threat and a challenge to the continuity that has helped to support biodiversity and ecological functions by upholding similar or only slowly changing adaptive cycles over time. Continuity is perpetuated through memory carriers, slowly changing variables and features that retain or make available information on how different situations have been dealt with before. Ecological memory carriers comprise memory banks, spatial connections and mobile link species. These can be supported by social memory carriers, represented by collectively created social features like habits, oral tradition, rules-in-use and artifacts, as well as media and external sources. Loss or lack of memory can be diagnoses by the absence or disconnect between memory carriers, as will be illustrated by several typical situations. Drawing on a set of example situations, we present an outline for a look-up table approach that connects ecological memory carriers to the social memory carriers that support them and use these connections to set diagnoses and indicate potential remedies. The inclusion of memory carriers in planning and management considerations may facilitate preservation of feedbacks and disturbance regimes as well as species and habitats, and the cultural values and meanings that go with them.

  • 34.
    Andersson, Harald
    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.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Energy-Saving Measures in a Classroom Using Low Pressure Drop Ceiling Supply Device: A Field Study2016In: 2016 ASHRAE Winter Conference Papers, ASHRAE, 2016Conference paper (Refereed)
    Abstract [en]

    Between 1990 and 2006 the energy use by ventilation systems in Swedish schools doubled. This is explained by high airflows in schools because of the high occupant density. Studies show that 87% of Swedish schools use constant air volume (CAV), and it is estimated that a change to variable air volume (VAV) could save 0.12-0.33 TWh (4.1*10(12) - 1.1*10(13) Btu) per year. Therefore the aim of this study is to investigate whether it is possible to replace displacement ventilation (DV) with mixing ventilation (MV) to create a comfortable indoor climate in a typical classroom and at the same time decrease the energy use by using VAV and Low Pressure Drop Ceiling Supply Device (LPDCSD). The study used two LPDCSDs which consist of circular channels with 190/228 round jets placed in an interlocking pattern, with a horizontal one/two-way-direction. The field study was carried out in a school which is intended to be extensively renovated. The school currently has DV and CAV. The study was carried out by installing MV with LPDCSD in one of the typical classrooms. Several different air-flow rates were investigated using tracer-gas technology to measure the local mean age of the air in the occupied zone. Simultaneously, thermal comfort and vertical temperature gradients were measured in the room. The results show nearly uniform distribution of the local mean age of air in the occupied zone, even in the cases of relatively low air-flow rates. Since the mixing of air is more or less the same in the entire occupied zone VAV can be used to reduce air-flow rate based on the desired CO2-level. Because of the number of students in each classroom and the fact that changes in air-flow rates have no significant effect on the degree of mixing, it is possible to reduce the air-flow rates for extended periods of time. Finally, since the LPDCSD has a lower pressure-drop than the currently used supply devices and it is possible to use VAV to lower the airflows in cases with reduced heat loads, it is possible to significantly reduce the energy usage in the school while maintaining the IAQ, increasing the thermal comfort and the available floor area of the occupied zone.

  • 35.
    Andersson, Harald
    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.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Experimental and numerical investigations of a new ventilation supply device based on confluent jets2018In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 137, p. 18-33Article in journal (Refereed)
    Abstract [en]

    In developed countries, heating, ventilation, air conditioning (HVAC) systems account for more than 10% of national energy use. The primary function of a HVAC system is to create proper indoor environment. A number of ventilation strategies have been developed to minimize HVAC systems’ energy use whilst still maintaining a good indoor environment. Among these strategies are confluent jet ventilation and variable air volume. In this study, an air supply device with a novel nozzle design that uses both of the above-mentioned strategies was investigated both experimentally and numerically at three different airflow rates. The results from the numerical investigation using the SST k - ω turbulence model regarding velocities and flow patterns are validated by experimental data carried out by Laser Doppler Anemometry. The results from both studies show that the flow pattern and velocity in each nozzle is directly dependent on the total airflow rate. However, the flow pattern does not vary between the three different airflow rates. The numerical investigation shows that velocity profiles for each nozzle have the same pattern regardless of the airflow rate, but the magnitude of the velocity profile increases as the airflow increases. Thus, a supply device of this kind could be used for variable air volume and produce confluent jets for the airflow rates investigated.

  • 36.
    Andersson, Kristina
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Biology.
    Danielsson, Anna
    Faculty of Education, University of Cambridge.
    Gullberg, Annica
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Biology.
    Hussénius, Anita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Chemistry.
    Acting for change: Challenging teachers through theatre, interventions and research2011Conference paper (Refereed)
  • 37.
    Andersson, Kristina
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Biology.
    Danielsson, Anna
    Institutionen för pedagogik, didaktik och utbildningsstudier, Uppsala universitet.
    Gullberg, Annica
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Biology.
    Hussénius, Anita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Chemistry.
    Chasing borderlands - pre-service teachers' meeting with different cultures in their education2012Conference paper (Refereed)
  • 38.
    Andersson, Kristina
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Biology.
    Gullberg, Annica
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Biology.
    Hussénius, Anita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Scantlebury, Kathryn
    Department of Chemistry and Biochemistry, University of Delaware, USA.
    "We do science, we don't do gender!" Challenging science teaching education: Gender awareness in contructing knowledge of science and science teaching2015In: Feminist Pedagogy in Higher Education : Critical Theory and Practice / [ed] T. P. Light, J. Nicolas & R. Bondy, Waterloo, ON, Canada: Wilfrid Laurier University Press , 2015Chapter in book (Refereed)
  • 39.
    Andersson, Maria
    et al.
    Department of Psychology, University of Gothenburg, Göteborg, Sweden .
    Eriksson, Ola
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    von Borgstede, Chris
    Department of Psychology, University of Gothenburg, Göteborg, Sweden .
    The Effects of Environmental Management Systems on Source Separation in the Work and Home Settings2012In: Sustainability, E-ISSN 2071-1050, Vol. 4, no 6, p. 1292-1308Article in journal (Refereed)
    Abstract [en]

    Measures that challenge the generation of waste are needed to address the global problem of the increasing volumes of waste that are generated in both private homes and workplaces. Source separation at the workplace is commonly implemented by environmental management systems (EMS). In the present study, the relationship between source separation at work and at home was investigated. A questionnaire that maps psychological and behavioural predictors of source separation was distributed to employees at different workplaces. The results show that respondents with awareness of EMS report higher levels of source separation at work, stronger environmental concern, personal and social norms, and perceive source separation to be less difficult. Furthermore, the results support the notion that after the adoption of EMS at the workplace, source separation at work spills over into source separation in the household. The potential implications for environmental management systems are discussed.

  • 40.
    Andersson, Martin
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Berge, Nils
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Energi- och miljökonsekvenser vid energieffektivisering av belysning och installation av solceller på Nacka Forum i Stockholm2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The use of energy is increasing worldwide and due to the threat of global warming more and more discussions are made about how the consumption could be reduced and at the same time more sustainable solutions is requested.Buildings consume 40 % of the total global energy where most of it comes from fossil fuels. To reduce the impact of the environment the EU (European Union) has set several goals for that where one is reducing its CO2-emission with 20 % compared to 2008 by the year 2020. One way to do so is from using more efficient technology. This work was made to reduce Nacka Forums electricity bills and that after it had been requested of their owner Unibail-Rodamco. The authors have only looked for solution in areas which the property owners are responsible for like services areas and public spaces. Ideas for reducing their energy use were obtained through studying literature. That study also showed that shopping malls use a lot of energy, especially electricity which mostly is consumed by the building’s lighting. Something that is becoming increasingly more common on buildings is solar cells. Solar cells do not only cut the electricity costs but also decreases the demand on fossil fuels. The shopping mall seemed to have good conditions for such an installation so an investigation was made to see if that could be useful. A plant with a power of 100 kWp was calculated to need 920 m2 roof surface and would yearly produce 93 534 kWh which the authors conclude that it would be a good investment and also highlights that an even bigger plant should be considered. After observing the lights two new solutions were proposed where LED-lamps was considered to be the best source for replacement. Just changing all the light sources would cut the electricity costs a lot but since the existing luminaires was considered to be at the end of their technical lifetime the best solution would therefore be to change both luminaires and light sources. Such solution would decrease the energy use with 544,4 MWh/year and has a payback period of 3,3 years. That energy saving would decrease the CO2-emission with 218 ton/year.This work shows that regardless of which solution that is chosen both of them would decrease the energy use and CO2-emission with 50 %.One of the stores in the shopping mall was using a lot of light which caused problem with the thermal comfort. Despite that, the store does not exceed the limit of 50 W/m2 that is set from the property owner. Such low requirements might hinder any efforts to reduce the energy use and also contribute to unnecessary heat.

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  • 41.
    Andersson, Niklas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Energieffektivisering av byggnad med enkla medel: en fallstudie på Hofors mödravårdscentral2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the central parts of Hofors a healthcenter is located which is included in Hoforshus AB's building stock, the building itself is divided into a main building and a smaller one in which the child health center and maternity care is located. The buildings are connected by a corridor substantially glazed. Now they are interested in maping the building's energyusage as this is relatively high, in addition, the users of the building had been dissatisfied with the indoor climate in both summer and winter. Because of the healtcare activities the owners were most interested in finding solutions that would not interfere with it.

    The study conducted has had a primary focus on the building envelope and above all on the glazed corridor’s impact on the rest of the building. One can assume that the high proportion of glass in this part of the building affects the indoor climate negatively keeping in mind the low U-value of the glass and the solar heat load, this gives during the summer when heat gain is not desired. A literature study to investigate how people perceive the climate as well as how to make a reliable simulation model of a building has been completed. The study resulted in an understanding of how the indoor climate is perceived and quantified, and also in an understanding of what is important in the collection of data for the simulation model.

    Keeping in mind how data should be collected according to the literature reviwe- have as much data as possible measured through surveys and own observations, blueprints have been studied and their validity has been investigated by measuring the building, blower door has been performed and temperature- and relative humidityloggning. Instantaneous values of the FTX system was made to calculate its efficiency. Linear thermal bridges have been investigated by finite element method in the program COMSOL Multiphysics 3.5. For validation of the simulated model the results of it were compared with the acutal measured energyconsumption of the building. The simulations were performed in BV2.

    The results of the study show, as expected, the glazed corridor’s negative impact on the building's indoor climate. Temperature was logged between 160412-160509 highest temperature was 30 ° C and minimum 15 ° C, which is more widespread than in other areas where the temperature was logged. The simulations that were performed on the glazed corridor shows that it consumes between 5000-5500 kWh on the area of 13.5 m2. Finally the study resulted in recommendations for the building that includes additional insulation of the attic, replacement of a smaller wall section, lowering the temperature by 1 ° C, as well as some maintenance measures to improve the indoor climate. The measures are believed to be possible to implement without significant interference with the health care acitivities. In addition the proposed measures seem profitable according to the pay of method.

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  • 42.
    Andersson, Robin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energibalansberäkning för flerbostadshus: projekterad energianvändning jämfört med beräknad energianvändning med uppmätta värden för Gävle Strand Etapp 12011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The estimated amount of energy that a building consumes during one year indicates whether it contributes to a sustainable society or not. The communal company, AB Gavlegårdarna , that rents out apartments, works not only with designing proposals for solutions for the future housing , they also work with improving their stock when it comes to energy consumption. The multi-family buildings of Gävle Strand Phase 1 were completed in 2008 with a population of twelve buildings that are shaped in four ways.

     

    During the planning phase a consultant was hired to calculate the how much energy these buildings would have to purchase and came up with an energy use of 92 kWh/m2,year. Gavlegårdarna’s own calculations are based on the actual values obtained for each apartment and in September 2009 and they showed a mean value for the whole stock, which was 114 kWh/m2,year.

     

    AB Gavlegårdarna want to find a solution to the problem and reduce the extra cost that Gävle Strand Phase 1 has given rise through increased use of energy. They want to perform precise calculations on each building's energy use. The problem can be formulated as follows:

    How much influence does the malfunction of a heat exchanger in a balanced ventilation system have on the total energy consumption in apartment buildings? Can a house among the various geometrically designed houses of a stock be considered to be representative when calculating the energy use of the stock as a whole?

    The report deals with a number of U-value and area calculations, ventilation and air leakage assessments, domestic hot water use and energy user behavior of the residents, to work out how much a simulated building uses in terms of specific energy, with unit kWh/m2,year. An building simulation program called BV2 2010was utilized.

    The results show that the majority of the buildings located in Gävle Strand Phase 1 have higher energy consumption than the consultant's basic case. This is due to several factors but the main causes of the high residential energy use is the low temperature efficiency in the FTX-system heat exchanger, the residents’ behavior and in some cases relatively high usage of hot water.

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  • 43.
    Angele, Kristian
    et al.
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Högström, Carl-Maikel
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Odemark, Ylva
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Henriksson, Mats
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Tinoco, Hernan
    Forsmarks Kraftgrupp AB, Östhammar, Sweden.
    Lindqvist, Hans
    Forsmarks Kraftgrupp AB, Östhammar, Sweden.
    Hemström, Bengt
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Flow Mixing Inside a Control-Rod Guide Tube: Part 2—Experimental Tests and CFD-Simulations2010In: 18th International Conference on Nuclear Engineering: Volume 4, Parts A and B, 2010, p. 655-663Conference paper (Refereed)
    Abstract [en]

    Alarge number of control rod cracks were detected during therefuelling outage of the twin reactors Oskarshamn 3 and Forsmark3 in the fall of 2008. The extensive damage investigationfinally lead to the restart of both reactors at theend of 2008 under the condition that further studies wouldbe conducted in order to clarify all remaining matters. Also,all control rods were inserted 14% in order to locatethe welding region of the control rod stem away fromthe thermal mixing region of the flow. Unfortunately, this measureled to new cracks a few months later due toa combination of surface finish of the new stems andthe changed flow conditions after the partial insertion of thecontrol rods. The experimental evidence reported here shows an increasein the extension of the mixing region and in theintensity of the thermal fluctuations. As a part of thecomplementary work associated with the restart of the reactors, andto verify the CFD simulations, experimental work of the flowin the annular region formed by the guide tube andcontrol rod stem was carried out. Two full-scale setups weredeveloped, one in a Plexiglass model at atmospheric conditions (inorder to be able to visualize the mixing process) andone in a steel model to allow for a highertemperature difference and heating of the control rod guide tube.The experimental results corroborate the general information obtained through CFDsimulations, namely that the mixing region between the cold crud-removalflow and warm by-pass flow is perturbed by flow structurescoming from above. The process is characterized by low frequent,high amplitude temperature fluctuations. The process is basically hydrodynamic, causedby the downward transport of flow structures originated at theupper bypass inlets. The damping thermal effects through buoyancy isof secondary importance, as also the scaling analysis shows, howevera slight damping of the temperature fluctuations can be seendue to natural convection due to a pre-heating of thecold crud-removal flow. The comparison between numerical and experimental resultsshows a rather good agreement, indicating that experiments with plantconditions are not necessary since, through the existing scaling lawsand CFD-calculations, the obtained results may be extrapolated to plantconditions. The problem of conjugate heat transfer has not yetbeen addressed experimentally since complex and difficult measurements of theheat transfer have to be carried out. This type ofmeasurements constitutes one of the main challenges to be dealtwith in the future work.

  • 44.
    Angele, Kristian
    et al.
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Odemark, Ylva
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Hemström, Bengt
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Högström, Carl-Maikel
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Henriksson, Mats
    Vattenfall Research & Development AB, Älvkarleby, Sweden.
    Tinoco, Hernan
    Forsmarks Kraftgrupp AB, Östhammar, Sweden.
    Lindqvist, Hans
    Forsmarks Kraftgrupp AB, Östhammar, Sweden.
    Flow mixing inside a control-rod guide tube: Experimental tests and CFD simulations2011In: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 241, no 12, p. 4803-4812Article in journal (Refereed)
  • 45.
    Antoniou, Nestoras
    et al.
    Department of Civil and Environmental Engineering, University of Cyprus, Nicosia, Cyprus; Department of the Built Environment, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Montazeri, Hamid
    Department of the Built Environment, Eindhoven University of Technology, Eindhoven, The Netherlands; Department of Civil Engineering, KU Leuven, Leuven, Belgium.
    Wigö, Hans
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Neophytou, Marina
    Department of Civil and Environmental Engineering, University of Cyprus, Nicosia, Cyprus.
    Blocken, Bert
    Department of the Built Environment, Eindhoven University of Technology, Eindhoven, The Netherlands; Department of Civil Engineering, KU Leuven, Leuven, Belgium.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    CFD and wind-tunnel analysis of outdoor ventilation in a real compact heterogeneous urban area: evaluation using “air delay”2017In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 126, p. 355-372Article in journal (Refereed)
    Abstract [en]

    Outdoor urban ventilation in a real complex urban area is investigated by introducing a new ventilation indicator – the "air delay". Computational Fluid Dynamics (CFD) simulations are performed using the 3D steady Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches. The up-to-date literature shows the lack of detailed evaluations of the two approaches for real compact urban areas. This study further presents a systematic evaluation of steady RANS and LES for the assessment of the ventilation conditions in a dense district in Nicosia, Cyprus. The ventilation conditions within the urban area are investigated by calculating the distribution of the age of air. To better assess the outdoor ventilation, a new indicator, the "air delay" is introduced as the difference between the local mean age of air at an urban area and that in an empty domain with the same computational settings, allowing the comparison of the results in different parts of the domain, without impact of the boundary conditions. CFD results are validated using wind-tunnel measurements of mean wind speed and turbulence intensity performed for the same urban area. The results show that LES can accurately predict the mean wind speed and turbulence intensity with the average deviations of about 6% and 14%, respectively, from the wind-tunnel measurements while for the steady RANS, these are 8% and 31%, respectively. The steady RANS simulations overestimate the local mean air delay. The deviation between the two approaches is 52% at pedestrian level (2 m).

  • 46.
    Apell, Oscar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energikartläggning av Fridhemsskolan 16:22014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Increased energy consumption in the world has created an increased supply of various fuels, especially fossil fuels. The Swedish government has set up various energy targets for 2020. To reach these goals it’s important to increase the energy efficiency in local buildings such as schools. This work illustrates the breakdown between energy supply and energy losses over the school. It also shows various suggestions to reduce the energy usage. The results shows that energy losses from transmission is definitely the greatest. Significant savings can be made by replacing windows, add insulation and install motion sensor lightning. If the proposed savings would be made, the energy consumption of the school could decrease by approximately 165MWh/year. This represent an annual saving of about 123600 SEK.

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  • 47.
    Arcos Usero, Lucía
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Analysis and improvements of outdoor hot benches in Gävle2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Five exterior hot benches have been installed in Gävle, in Kyrkogatan street by the company Gävle Energi with the aim of achieving the wellnes of people that sit on them. This system uses the residual heat from the district heating, representing consequently a non-polluting system. However, the temperature desired on the surface, 35°C is not always achieved before different exterior conditions. For this reason, Gävle Energi is interested in carrying out a study about enhancements that could be made in the system in order to take them into account for future projects of this kind of technology.

     

    The aim of this project is analysing if it would be possible to achieve the requirements established by Gävle Energi, changing with this objective all the necessary system parameters of the current system such as diameter of the pipes, materials, number of turns... These requirements consist of working with a supply temperature of 40, 45 and 50°C when the exterior conditions are 0, -5 and -10°C respectively, accomplishing always 35°C on the surface. Moreover, in case that it was not possible, providing the company with the characteristics of the system that would make the system as efficient as possible, specifying for different exterior temperatures the mass flow, pressure drop, velocity and needed power.

     

    The study has been developed by different simulations with the software COMSOL, whose use requires a high knowledge on heat transfer. After several simulations, it has been checked that it is not possible to accomplish the requirements established by the company. However, a new more efficient design has been designed because the supply temperatures of the system to accomplish an average temperature of around 35°C on the surface have been minimised. For that, several changes have been carried out. The number of pipes turns have been increased from 12 to 17, their total diameter from 20mm to 30mm and the distance between the centres of the pipes from 5.5cm to 4cm. The 2mm of outer plastic thickness of the pipes has been replaced by copper and the height of the pipes has been moved 2cm upwards.

     

    With all these changes, the final length of the pipes inner the stones has a value of 40.6m and the supply temperatures reach 46, 47 and 49°C for the 0,-5 and -10°C exterior conditions respectively. Apart from the supply temperatures for the study cases, the ones necessary to accomplish always the temperature desired on the surface for other exterior temperatures have been provided together with the amount of power necessary, velocity flow, volumetric flow and pressure drop for all the different cases. These values would allow the company to work always at the optimum point as well as to design the heat pump for the system.

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    Thesis project Lucía Arcos
  • 48.
    Arghand, Taha
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Human subjective response to combined radiant and convective cooling by chilled ceiling combined with localized chilled beam2015Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The aim of the present research is to identify human subjective response (health and comfort) to the micro-thermal environment established by integration of individually controlled localized chilled beam and chilled ceiling (LCBCC) system and to compare its performance with the performance of mixing ventilation combined with chilled ceiling (CCMV).Experiments were carried out in mock-up of an office (4.1 m × 4.0 m × 3.1 m, L× W× H) with one person under two summer temperature conditions (26 °C and 28 °C). To mimic direct solar radiation in the room, five radiative panels on the wall together with electrical sheets on the half of the floor were used. The test room was set-up with two desks, as two workstations, and one laptop on each table. The main workstation (WS1) was located close to the simulated window. The second work station (WS2) was placed in the opposite side of the room. The room was equipped with two types of ventilating and cooling systems.  The first system consisted of a localized active chilled beam (LCB) unit together with chilled ceiling (CC) panels. The LCB was installed above the WS1 to create micro-environment around the occupant sitting at the desk. The supply flow rate from the LCB could be adjusted by the occupant within the range of 10 L/s to 13 L/s by means of a desk-mounted knob. The integration of mixing ventilation (MV) system and chilled ceiling panels was the second ventilating and cooling strategy. Twenty- four subjects (12 female and 12 male) were exposed to different indoor environment established by two cooling systems. Each experiment session lasted 120 min and consisted of 30 min acclimatization period and 90 min exposure period. The performance of the systems was identified and compared by physical measurements of the generated environment and the response of the human subjects.

    The study showed that perceived air quality (PAQ), overall thermal sensation (OTS) acceptability and local thermal sensation (LTS) acceptability clearly improved inside the micro-environment by using LCBCC system. Moreover, at the main workstation, OTS and LTS votes were close to “neutral” thermal sensation (ASHRAE seven point scale) when LCBCC system was used. However, OTS and LTS votes increased to the “slightly warm” side of the scale by applying CCMV system which implied the better cooling performance of the LCBCC system. Acceptability of work environment apparently increased under the room condition generated by LCBCC system.

    In agreement with human subjective study, the results from physical measurements and thermal manikin study showed that uniform thermal condition was generated all over the room. Air and operative temperature distribution was almost uniform with no difference higher than 1 °C between the measured locations in the room. Thus, both LCBCC and CCMV systems performed equally well outside of the micro-environment region. The use of the chilled ceiling had impact on the airflow interaction in the room and changed the airflow pattern. It can be concluded that the combination of convective and radiative systems can be considered as an efficient strategy to generate acceptable thermal condition in rooms.

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  • 49.
    Arghand, Taha
    et al.
    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.
    Awbi, Hazim
    School of Construction Management and Engineering, University of Reading, United Kingdom.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Larsson, Ulf
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Linden, Elisabet
    University of Gävle, Faculty of Engineering and Sustainable Development, BMG laboratory.
    An experimental investigation of the flow and comfort parameters for under-floor, confluent jets and mixing ventilation systems in an open-plan office2015In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 92, p. 48-60Article in journal (Refereed)
    Abstract [en]

    There is a new trend to convert the workplaces from individual office rooms to open offices for motivating money saving and better communication. With such a shift the ability of existing ventilation systems in meeting the new requirements is a challenging question for researchers. The available options could have an impact on workers' health in terms of providing acceptable levels of thermalcomfort and indoor air quality. Thus, this experimental investigation focuses on the performances of three different air distribution systems in an open-plan office space. The investigated systems were: mixing ventilation with ceiling-mounted inlets, confluent jets ventilation and underfloor air distribution with straight and curved vanes. Although this represents a small part of our more extensiveexperimental investigation, the results show that all the purposed stratified ventilation systems (CJV and UFAD) were more or less behaving as mixing systems with some tendency for displacement effects. Nevertheless, it is known that the mixing systems have a stable flow pattern but has the disadvantage of mixing contaminated air with the fresh supplied air which may produce lower performance and in worst cases occupants' illness. For the open-plan office we studied here, it will be shown that the new systems are capable of performing better than the conventional mixing systems. As expected, the higher air exchange efficiency in combination with lower local mean age of air for corner-mounted CJV and floor-mounted UFAD grills systems indicates that these systems are suitable for open-plan offices and are to be favored over conventional mixing systems.

  • 50.
    Arizcun Zúñiga, Paula María
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Ram pump hydraulic air test. Pressure conditions and flow measurements: Experimental research and case study2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study consists of the development of a ram pump, which will allow the pumping of water without the need of external energy sources. It is considered an analysis of interest since, once it is finished; it can be applied in reality improving and facilitating different activities related to agriculture and health.

    Previous studies have been made related to the ram pump; however, in this case, it is intended to understand the system that has been built in the laboratory in order to find the best combination of parameters that will lead to obtain the highest possible efficiency. 

    The study will be carried out by studying scientific literature and by experimenting in the laboratory. Encompassing the experimental and literary field, it is expected to understand perfectly the advantages and disadvantages of the ram pump in order to determine if it is worth it to install in certain places.

    After the study, the most favourable parameters for the operation of the Bruzaholms Bruk pump have been obtained. It has been found that the use of a longer drive pipe favours the operation of the system, as it is possible to obtain a higher efficiency, although it must be taken into account that the mentioned length needs to be controlled, as it could reduce the working rhythm of the pump. It has also been seen that the pump gives better results if the impulse valve is completely opened. Finally, it has been proven that, as long as the height difference between the two tanks is enough, increasing the height of the water source will favour the operation of the system.

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