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  • 1.
    Abad, Marta
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    WORK WITH AGENDA 21 IN EUROPEAN CITIES.: A case of study: the waste's management in Barcelona and Gävle2008Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sweden is a long-term world reference country in terms of sustainable development. On the other hand, Barcelona has recently made great efforts in order to improve and to make society aware of the importance of environmental issues. Hence, it would be interesting to investigate if these efforts had succeeded in the waste’s management in Barcelona compared to other leading European cities, and particularly to the case of Gävle.

    In this work, the operation of the management of the urban solid wastes of the two cities is explained.

    First, the objectives marked by Agenda 21 of each locality are exposed. Next, a theoretical perspective about management, generation of wastes and types of waste treatment is provided. In the following chapter, the results of the generation of wastes, selective collection and the treatments of the wastes are shown for both the cases of Barcelona and Gävle until the 2006.

    Finally, the two cities are compared and the results obtained in the management of the wastes are discussed.

    The conclusion in this study is that Barcelona has improved noticeable in terms of environmentally safe management of the wastes. This has happened thanks to the efforts of the city council and of the citizens.

    But It is still necessary to make a major effort by the inhabitants of Barcelona.

    Fulltekst (pdf)
    FULLTEXT01
  • 2.
    Abellán Guallarte, Alejandro
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Energy analysis between traditional hot water circulation system and an innovative pipe-in-pipe system2022Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    We are at a time when energy efficiency and the reduction in the use of non-renewable energy is an important objective in all aspects and will continue to be so, therefore it is necessary to try to reduce energy and heat losses in the systems used in homes and, in particular, in the domestic hot water (DHW) system. This study aims to find out the advantages and disadvantages of an innovative pipe-in-pipe (PIP) system for DHW circulation with respect to the conventional system of two separate pipes. Previous studies have shown that DHW circulation is indeed an important point of energy losses in the home and that it is possible to reduce these losses by using the innovative system under study. The properties and coefficients defining the heat transfer system have been obtained for both the traditional and innovative systems by using empirical equations and iterative processes, indicating a 32% reduction in heat losses in favour of the pipe-in-pipe system. However, this result has been obtained in a kind of case study, using some simplifying assumptions, needed to accomplish to work within limited time. So the result could vary if a somewhat different system is studied, which is why it is necessary to carry out further studies and research on this subject in order optimize DHW systems in buildings.

    Fulltekst (pdf)
    fulltext
  • 3.
    Abeywardana, Asela Janaka
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Solar - Biomass hybrid system for process heat supply in medium scale hotels in Sri Lanka2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    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.    

    Fulltekst (pdf)
    SEE_KTH_HIG_AJA1
  • 4.
    Abolghasemi Moghaddam, Saman
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap.
    The effects of low-emissivity window films on thermal comfort and energy performance of a historic stone building in cold climate: computer simulations with "IDA ICE"2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Low-emissivity (low-E) window films are designed to improve the energy performance of windows and prevent indoor overheating by solar radiation. These films can be applied to different types of glazing units without the need for changing the whole window. This characteristic offers the possibility to improve the energy performance of the window of old and historic buildings for which preservation regulations say windows should remain more or less unchanged. This research aims to figure out to what extent a low-E window film can improve thermal comfort and energy performance of an old three-storey historic stone building in the cold climate of Mid-Sweden. In this research, first, with help of the simulation software “IDA ICE”, the entire building was modelled without window films in a one-year simulation. Second step was to add the low-E window films (3M Thinsulate Climate Control 75 (CC75)) to all the windows and repeat the simulation. Comparison between the results of the two cases revealed an improvement in energy use reduction as well as the thermal comfort when applying the films. For the application of the window films, a cost analysis using payback method was carried out which showed a long- time payback period. Although an investment with a long-time payback period is considered as a disadvantage, for historic buildings with very strict retrofit regulations specially when it comes to the building’s facades, application of the low-emissivity window films for better energy performance and thermal comfort is among the recommendable measures, but not necessarily the best.

    Fulltekst (pdf)
    fulltext
  • 5.
    Agbauduta, Stephen Ogba
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    SPATIAL MCDA FOR FINDING SUITABLE AREAS FOR HOUSING CONSTRUCTION2013Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Demand for residential houses in urban areas has become a major problem facing town planners today. With the high increase in urbanization due to the increase in population, residential houses are becoming more difficult to find. Planners aim at developing new ideas to combat the high increase in the demand for residential buildings. In recent times, different methods of analysis have been introduced that will help planners select best locations to erect residential houses.

    A Geographic information system (GIS) is one of the tools for analyzing and storing a great deal of information. Over the years, GIS technology has been introduced into planning and the result has been of great help to urban planners in planning sustainable environment for residents. This research aims at using GIS technology and multi-criteria decision analysis (MCDA) to determine possible locations to build residential houses and analyzing different methods of selecting suitability areas within the study area. An MCDA map was produced from the combination of different factors and constraint which include elevation, orientation of the building (direction), the soil type and land use type. Proximity analysis was also done to find out how infrastructures (existing roads, shopping malls and health care enter) are close to the study area. Results show that the southern, eastern, and a part of western side of the study area is better to build residential houses than other areas.

    Three different methods (visual interpretation method, seeding method and neighborhood method) where used to find out which method produces the most suitable locations within the study area. In order to calculate the suitability areas and suitability values, the sum of pixel values were calculated for each method. The visual interpretation method servers as a standard method of deciding the suitability area covers 15,375 m² and has the highest suitability values of about 500 pixels. The seeding method was used as an automatic method for selecting the suitability area; result shows that the suitability area covers 17,421 m² and has the highest suitability value of about 1200 pixels. The neighborhood method was calculated using two different statistics (mean statistics and majority statistics). The mean statistics covers an area of 12,439 m² while the majority statistics covers an area of 14,332 m². From analysis carried out, the seeding method is preferred for selecting suitability areas than the visual interpretation method and the neighborhood method but the visual interpretation method covers more suitability area than the seeding method and neighborhood method.

    Fulltekst (pdf)
    Agbauduta Ogba
  • 6.
    Aguirre Sánchez, Mikel
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Air flow disturbance by moving objects at local exhaust ventilation2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    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.

    Fulltekst (pdf)
    fulltext
  • 7.
    Ahlund, Viktor
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Energikartläggning av förskolan Smultronstället2015Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta är ett examenarbete på grundnivå, 15 högskolepoäng. Examensarbetet är en energikartläggning med rekommenderade energieffektiviseringsåtgärder. Energikartläggningen är baserad på ett verkligt objekt vilket är en förskola i norra Gävle. Denna skola förvaltas av Gavlefastigheter.I Sverige går cirka 40 % av energianvändningen till bostäder och service. Därför finns det stora mängder energi att spara inom denna sektor. Ett bra sätt att utreda på vart energin går i en byggnad är att göra en energikartläggning.Energikartläggningen är utförd utifrån ritningar, verkliga mätningar, schablonvärden, antaganden och litteratur.Skolan har en beräknad energianvändning på 1239 MWh per år, detta är uppdelat på ventilation, transmissionsförluster och tappvarmvatten. Efter 3 beräknade effektiviseringsåtgärder blir energibesparingen sammanlagt 612 MWh detta är 49,4 %. De åtgärder som är beräknade är tilläggsisolering, byte av ventilation och byte av fönster. Att enbart byta till FTX-ventilation sparar 522 MWh detta är en besparing på 42,1 % av den totala energianvändningen och den rekommenderade åtgärden.

    Fulltekst (pdf)
    fulltext
  • 8.
    Ahmed, Basem
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Investigation of energy retrofits of a multi-family building by using IDA Simulation Software2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    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.

    Fulltekst (pdf)
    fulltext med korrigerad TOC
  • 9.
    Akander, Jan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Moshfegh, Bahram
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Department of Management and Engineering, Division of Energy Systems, Linköping University.
    Assessing the Myths on Energy Efficiency When Retrofitting Multifamily Buildings in a Northern Region2017Inngår i: Sustainable High Rise Buildings in Urban Zones: Advantages, Challenges, and Global Case Studies / [ed] Ali Sayigh, Cham: Springer Publishing Company, 2017, 1, s. 139-161Kapittel i bok, del av antologi (Annet vitenskapelig)
    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.

  • 10.
    Al hamdany, Yarub
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Simulering och energieffektivisering för en kontorsbyggnad iForsmark2018Independent thesis Basic level (university diploma), 180 hpOppgave
    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.

    Fulltekst (pdf)
    examensarbete-11
  • 11.
    Alasadi, Rasha
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Matsson, Sofie
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap.
    Kvartersnära insamling av hushållsavfall: - Ett förslag till bostadsbolaget Ljusdalshem2020Independent thesis Basic level (degree of Bachelor), 180 hpOppgave
    Abstract [sv]

    Sammanfattning

    Varje år sorteras hushållsavfall felaktigt, vilket leder till att mycket av materialet går till förbränning istället för återvinning. Genom att utöka källsorteringen av hushållsavfall kan materialet återvinnas och cirkuleras i ett kretslopp. Trots de lagar och förordningar som finns vad gäller insamling av hushållsavfall, fortsätter mängden avfall att öka. En ny förordning har tagits fram av Regeringen för att motverka detta. Den nya förordningen som träder i kraft år 2025 innebär att alla bostadsfastigheter ska ha kvartersnära insamling. 

     

    Syftet med studien är att hjälpa bostadsbolaget Ljusdalshem med att ta fram ett förslag om kvartersnära insamling i området Gärdeåsen, som ligger i Ljusdal kommun. Området Gärdeåsen är byggt under miljonprogrammet. Området har enbart två fraktioner med insamling av brännbart och kartong. För att kunna genomföra detta arbete har en kvalitativ metod använts med hjälp av en litteraturstudie, flerfallstudie och semistrukturerade intervjuer. Två tidigare projekt har studerats för att få med viktiga aspekter i förslaget. De projekt som har studerats är Nordost och Andersberg, som har implementerat kvartersnära insamling av bostadsbolaget Gavlegårdarna i Gävle. Projekten skiljer sig i utformning och var därför av intresse att studera för att ta in viktiga aspekter när förslaget om kvartersnära insamling formas till bostadsbolaget Ljusdalshem. 

     

    Resultatet presenterar ett förslag till Ljusdalshem för implementering av kvartersnära insamling i området Gärdeåsen. Det som författarna kom fram till i denna studie var att bygga fyra nya återvinningsrum, med insamling för tidningar, förpackningar. Nya återvinningsrum har föreslagits med anledning av att de befintliga byggnaderna är slitna och renovering skulle bli omfattande. Det finns viktiga aspekter att se över när kvartersnära insamling byggs. En viktig aspekt för att förhindra lukt är att plocka ut mat-och restavfall från återvinningsrummet, därför bör de fyra återvinningsrum kompletteras med underjordsbehållare för mat-och restavfall. För att få ett effektivt resultat av sorteringen av hushållsavfall har beteendeförändringar hos de som bor i området en stor betydelse i förslaget, eftersom det finns en kunskapsbrist i områden med blandad kulturell mångfald. Ljusdalshem bör arbeta med informativa åtgärder. Detta gör att kunskap främjas och sorteringen av hushållsavfall kan öka. Den fysiska utformningen är också viktig för att öka sorteringen. Belysning, stora fönster och ljusa väggar, är åtgärder som främjar trygghetskänslan i återvinningsrummet för de boende. 

    Fulltekst (pdf)
    Kvartersnära
  • 12.
    Alcheikh, Ahmad
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    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 poäng / 15 hpOppgave
    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. 

    Download (pdf)
    Master Thesis
  • 13.
    Alcoverro Colom, Pau
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    A new energy model for the Lakshadweep islands: Change from a diesel-based model to a hybrid model with renewable energy systems considering the ecological fragility of the islands2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    A new energy model for the Lakshadweep islands
  • 14.
    Ali, Fadi
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Samhällsbyggnad, GIS.
    Urban classification by pixel and object-based approaches for very high resolution imagery2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Recently, there is a tremendous amount of high resolution imagery that wasn’t available years ago, mainly because of the advancement of the technology in capturing such images. Most of the very high resolution (VHR) imagery comes in three bands only the red, green and blue (RGB), whereas, the importance of using such imagery in remote sensing studies has been only considered lately, despite that, there are no enough studies examining the usefulness of these imagery in urban applications. This research proposes a method to investigate high resolution imagery to analyse an urban area using UAV imagery for land use and land cover classification. Remote sensing imagery comes in various characteristics and format from different sources, most commonly from satellite and airborne platforms. Recently, unmanned aerial vehicles (UAVs) have become a very good potential source to collect geographic data with new unique properties, most important asset is the VHR of spatiotemporal data structure. UAV systems are as a promising technology that will advance not only remote sensing but GIScience as well. UAVs imagery has been gaining popularity in the last decade for various remote sensing and GIS applications in general, and particularly in image analysis and classification. One of the concerns of UAV imagery is finding an optimal approach to classify UAV imagery which is usually hard to define, because many variables are involved in the process such as the properties of the image source and purpose of the classification. The main objective of this research is evaluating land use / land cover (LULC) classification for urban areas, whereas the data of the study area consists of VHR imagery of RGB bands collected by a basic, off-shelf and simple UAV. LULC classification was conducted by pixel and object-based approaches, where supervised algorithms were used for both approaches to classify the image. In pixel-based image analysis, three different algorithms were used to create a final classified map, where one algorithm was used in the object-based image analysis. The study also tested the effectiveness of object-based approach instead of pixel-based in order to minimize the difficulty in classifying mixed pixels in VHR imagery, while identifying all possible classes in the scene and maintain the high accuracy. Both approaches were applied to a UAV image with three spectral bands (red, green and blue), in addition to a DEM layer that was added later to the image as ancillary data. Previous studies of comparing pixel-based and object-based classification approaches claims that object-based had produced better results of classes for VHR imagery. Meanwhile several trade-offs are being made when selecting a classification approach that varies from different perspectives and factors such as time cost, trial and error, and subjectivity.

          Classification based on pixels was approached in this study through supervised learning algorithms, where the classification process included all necessary steps such as selecting representative training samples and creating a spectral signature file. The process in object-based classification included segmenting the UAV’s imagery and creating class rules by using feature extraction. In addition, the incorporation of hue, saturation and intensity (IHS) colour domain and Principle Component Analysis (PCA) layers were tested to evaluate the ability of such method to produce better results of classes for simple UAVs imagery. These UAVs are usually equipped with only RGB colour sensors, where combining more derived colour bands such as IHS has been proven useful in prior studies for object-based image analysis (OBIA) of UAV’s imagery, however, incorporating the IHS domain and PCA layers in this research did not provide much better classes. For the pixel-based classification approach, it was found that Maximum Likelihood algorithm performs better for VHR of UAV imagery than the other two algorithms, the Minimum Distance and Mahalanobis Distance. The difference in the overall accuracy for all algorithms in the pixel-based approach was obvious, where the values for Maximum Likelihood, Minimum Distance and Mahalanobis Distance were respectively as 86%, 80% and 76%. The Average Precision (AP) measure was calculated to compare between the pixel and object-based approaches, the result was higher in the object-based approach when applied for the buildings class, the AP measure for object-based classification was 0.9621 and 0.9152 for pixel-based classification. The results revealed that pixel-based classification is still effective and can be applicable for UAV imagery, however, the object-based classification that was done by the Nearest Neighbour algorithm has produced more appealing classes with higher accuracy. Also, it was concluded that OBIA has more power for extracting geographic information and easier integration within the GIS, whereas the result of this research is estimated to be applicable for classifying UAV’s imagery used for LULC applications.

    Fulltekst (pdf)
    fulltext
  • 15.
    Ali, Sabir
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Building Information Modelling for Energy Analysis and Environmental Assessment: The comparison of LEED and Miljöbyggnad for two school buildings in Gävle, Sweden2022Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The building sector is one of the largest energy consumers and there are global efforts toward sustainable and energy-efficient new buildings and existing buildings retrofit. The application of Building Information Modelling (BIM) in environmental assessment was practiced and studied following the increasing number of projects adopting the BIM workflows and pursuing green building certifications. The interest of this thesis is to study the use of different Building Information Modelling tools used globally for energy and environmental assessment to examine their practical benefits and challenges. Case studies of two primary school buildings that achieved the Swedish Miljöbyggnad system were used to compare what could have been achieved with Leadership in Energy and Environmental Design (LEED) categories of energy and atmosphere and indoor environmental quality to what has been achieved in similar Miljöbyggnad areas. A review and summary of energy and atmosphere and indoor environmental categories in the LEED version 4 user’s guide is presented to evaluate the case study potential score in them.

    The early adoption of modeling in the evaluation from the conceptual design is the best approach to achieve better performance. It will improve the way of working and result in a more efficient and sustainable building.

    The Building Information Modelling software can be used directly in assessment using the integrated modules within the popular authoring tools such as Revit’s lighting and Insight the cloud base service or by transferring the model data to a stand-alone tool like IDA-ICE. The energy plug-ins of the authoring tools such as Revit are still lacking full control over the analytical model and the limited input options.

    The identified and discussed advantages of Building Information Modelling implementation are collaboration, accuracy, time, and cost saving. Data exchange issues, knowledge, and the differences in assessment tools were discussed as implementation barriers.

    Although the full comparison of certification systems is difficult, the comparison between the potential LEED score and achieved Miljöbyggnad rating showed some differences and similarities in the rating systems. The comparison requires rearranging the rating system indicators into unified categories. The framework that compares the scope, structure, content, and aggregation, would give a meaningful comparison. The way that the LEED and Miljöbyggnad are rewarding the indicators and the aggregation of aspects towards the final rating is totally different.

    Fulltekst (pdf)
    fulltext
  • 16.
    Almquist, Olivia
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Testrutin för dricksvattenfilter för upp till 50 P.E.: ett förslag på tillvägagångssätt2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med rapporten är att med lagstiftningen kring dricksvattenfilter upp till 50 p.e. som grund kunna skapa en rutin för hur tester ska gå till för filtren i en testbäddsanläggning. Hur ska en gemensam testrutin vara utformad för bäst bedömning av dricksvattenfilter idag?

     

    Rapporten är en litteraturstudie i form av både hemsidor och lagstiftning. Informationen från hemsidorna har hämtats från relevanta företag i form av exempelvis Livsmedelsverket och liknande organisationer som arbetar med dricksvattenfrågor. Medan den lagstiftade informationen har hämtats från exempelvis Statens Offentliga Utredning och liknande. Flera av referenserna som är använda har uppbackning från flera andra källor vilket bör betyda att informationen är pålitlig. Lagstiftningen är utgångspunkten för ett fungerande Sverige vilket också bör betyda att den är tillförlitlig.

     

    Det har även gjorts en enkätundersökning via mail där cirka 50 företag inom dricksvattenfilter branschen tillfrågats vad dessa tycker om olika påståenden. Frågorna baserades på ett redan framtaget förslag till en testrutin som författaren tagit fram tidigare. Metoden valdes på grund av att det är svårt att få en klar bild av vad marknaden är intresserad av att undersöka utan att fråga dem.

     

    Vatten i sin råa form H2O varken smakar eller luktar något. Det kan dock förändras när det kommer i kontakt med andra material. Detta på grund av att vatten är lättlösligt och på så sätt löser ut andra ämnen. Därför är det viktigt att det är säkra material som används vid dricksvattenhantering då konsumenten annars kan få i sig ohälsosamma ämnen via dricksvattnet. Boverket tillsammans med Livsmedelsverket samt Kemikalieinspektionen ska konstruera en plattform där berörda parter lätt ska hitta information angående godkända material i kontakt med dricksvatten.

     

    Det är cirka 1,2 miljoner hushåll i Sverige (både permanenta- och fritidsboenden) som får sitt dricksvatten från egen brunn. Det ligger på brunnsägarens egna ansvar att dricksvattnet har en bra kvalitet. Det finns ingen lagstiftning kring kontroll av eget dricksvatten. Rekomendationen lyder provtagning vart tredje år om brunnen endast försörjer ett hushåll men varje år om det är fler hushåll än så. Cirka 1/5 av allt dricksvatten beräknas vara otjänligt.

     

    Det finns många olika typer av filter och metoder vilket kan göra det förvirrande och svårt för personer att välja rätt. Några olika typer är Jonbytarfilter, Aktivt kol, Omvänd osmos, sandfilter, Luftfilter, Patronfilter, UV-ljus och kalkfilter. Filtren har olika egenskaper och arbetar på olika sätt. Enligt WHOs riktlinjer för tjänligt dricksvatten är många ämnen med utan gränsvärden då WHO inte anser att koncentrationerna kommer upp i sådan mängd att det påverkar människan negativt.  Exempel på dessa är pH, järn, klorid, mangan och kalium. Även EU har en lista för tjänligt dricksvatten vilken Livsmedelsverket baserar sina gränsvärden på.

     

    Den föreslagna testrutinen blev något kortare samt snällare än rutinen som den grundade sig på. Den redovisas i Bilaga 2 tillsammans med enkäten som skickades ut till företagen för att få veta vad de tyckte om förslaget på testrutinen. Dricksvattenfiltren ska testas i 32 veckor då bland annat funktionen under och efter ett strömavbrott ska testas. Även hur filtret klarar reningen vid högt flöde samt inget flöde under ett visst antal timmar respektive veckor. 

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    fulltext
  • 17.
    Alonso, Laura
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Assessment of waste and biofuel resources for district heating in the region of Gävle in Sweden2008Independent thesis Advanced level (degree of Magister), 10 poäng / 15 hpOppgave
    Abstract [en]

    Fuel availability and security of supply are two of the most important factors in the well functioning of a company like Gävle Energi. Another important factor is the price of the fuels used. The transportation cost plays also an important role when purchasing fuels from different sources. Currently the fuels used in Gävle Energi are mainly woody biofuels, but waste and peat could also be used in the future.

    The aim of this thesis is to provide an overview of the different available biofuels in the region of Gävle. The fuels considered in the study are:

    - Bark

    - Forest Residues

    - Wood waste

    - Pellets and Briquettes

    - Garbage/waste materials

    - Peat

    The research is focused on the physical properties of the fuels, their price and transportation cost, environmental and legislation issues and the availability in the region of Gävle. A 10-year perspective is defined for an estimated availability of the different fuels in te region.

    Fulltekst (pdf)
    FULLTEXT01
  • 18.
    Alonso Lozano, Alvaro
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Coal gasification in entrained flow gasifiers simulation & comparison2012Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    Coal gasification
  • 19.
    Alvarez Sarró, Jesús
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Assessing the Integration of Sustainable Aviation Fuels (SAFs): Balancing Environmental Impact, Economic Viability, and Aircraft Performance in the Aviation Industry2024Independent thesis Advanced level (degree of Master (One Year)), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    This thesis examines the role of Sustainable Aviation Fuels (SAFs) in advancing the sustainability goals of the aviation industry, focusing on their environmental impacts, economic feasibility, and compatibility with existing aircraft performance. The research primarily involves a comprehensive literature review and analysis of existing studies to evaluate the potential of SAFs to reduce carbon emissions significantly—up to 80% relative to conventional jet fuels depending on the feedstock and processing methods used.

    The economic analysis reveals that while SAFs are currently more costly than traditional fuels, regulatory incentives and technological advancements could decrease these costs, making SAFs more competitive. Performance-wise, SAFs are shown to be viable "drop-in" options, requiring minimal modifications to aircraft or fuel infrastructure, thus facilitating easier adoption across the industry.

    The study concludes that despite the challenges, SAFs are indispensable for the aviation sector’s transition towards net-zero emissions. It emphasizes the need for enhanced collaboration among governments, industry stakeholders, and researchers to scale production and integrate SAFs into the global fuel mix effectively.

    Fulltekst (pdf)
    fulltext
  • 20.
    Ameen, Arman
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    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 poäng / 15 hpOppgave
    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.

    Fulltekst (pdf)
    Examensarbete_Arman
  • 21.
    Ameen, Arman
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Experimental and numerical study of corner impinging jet ventilation for an office environment2024Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    An effective ventilation system is an important component of a building’s service infrastructure. It serves the dual purpose of creating a comfortable and healthy indoor environment for occupants, thereby enhancing their well-being and productivity. However, the ventilation system is also a part of the building that uses a high amount of energy.

    The main objective of this study is to evaluate a novel implementation of the impinging jet ventilation system by placing the supply inlet at the corners of the space or room, rather than in the traditional mid-wall section. The focus of this study is to test and evaluate corner impinging jet ventilation in a medium-sized office environment within a building that requires moderate amount of heating and cooling.

    In the first part of this study (summer condition), the system is evaluated in an experimental environment, where it is compared against other systems such as displacement ventilation and mixing ventilation. The evaluated parameters indicates that corner impinging ventilation system performs better than mixing ventilation but show similar results to displacement ventilation in terms of airchange effectiveness. This experimental setup was also tested in winter condition and the results showed that the system was most effective during summertime compared to wintertime. In wintertime the results for the air change effectiveness were similar to those of a mixing system.

    In the second part, numerical simulations were utilized to delve deeper into the behaviour of the corner impinging jet ventilation system close to the floor surface. A numerical model was created and validated against experimental measurements. In this part, the spreading of the air jet across the room floor was examined, and its relation to various parameters such as inlet velocity, inlet shape and discharge height. Results indicated that diffuser geometries have almost no impact on velocity profile along the floor's centreline, jet spreading rate and maximum velocity decay. The results also showed a high degree of flexibility for the room size, between 25-100 m2 for which the results were applicable. The results also concluded that there was a noticeable confinement effect present and that the jet was able to travel far into the room.

    In the third part numerical simulations was used for validating and to create a model for an office room containing two office workstations. The office room was evaluated in terms of local thermal comfort, close to the sitting area. In addition, the indoor air quality was also examined. The results showed that corner impinging ventilation system performed better than conventional mixing ventilation system, especially when evaluating the indoor air quality in terms of mean age of air. This evaluation also took into account both outdoor summer and winter conditions, as well as different inlet surface areas. Different locations for the workstations were also evaluated with good results, except for placing the work-stations close to the inlets. Due to the system’s effectiveness of providing fresh air to the occupants, further analysis was made to try and reduce the air flowrate but keep the same indoor air quality level as an equivalent fully mixing ventilation system. By using this method, the study was able to demonstrate reduction in the energy use by reducing the air flowrate of the supply inlet. The study showed a possible reduction of the energy use by 7-9 % for outdoor temperatures ranging between -15 °C to 25 °C.

    Fulltekst (pdf)
    fulltext
    Download (jpg)
    presentationsbild
  • 22.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Elousa Ansa, Ibai
    Assessment of Thermal Comfort and Indoor Air Quality in Library Group Study Rooms2023Inngår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 5, artikkel-id 1145Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Human performance and health are among the most relevant topics in the modern society, especially at young ages, when academic performance is indispensable. Thus, as humans spend most of their lifetime inside a building, thermal comfort and indoor air quality are an essential aspect of a room. The aim of the current study is to numerically evaluate the main thermal comfort parameters such as PMV and PPD as well as indoor air quality, i.e., CO2 concentration, in library group study rooms at the University of Gävle in Sweden. Rotroninc Measurement Solutions CL11 sensors were utilized for temperature measurements. Simulation models were created and validated based of building data as well as temperature measurements. Several simulations were conducted throughout a year, covering different periods. The results show that even though the ventilation system, with only temperature control, works as intended for maintaining the thermal comfort, the CO2 concentration rises above 1000 ppm when more than one student occupy the rooms, which is not recommended by different thermal comfort ruling institutions. Consequently, a modification to the ventilation system control is recommended, changing it from temperature control to CO2 and temperature control.

    Fulltekst (pdf)
    fulltext
  • 23.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Karimipanah, Taghi
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Numerical investigation of indoor thermal comfort and air quality for an office equipped with corner impinging jet ventilation2023Inngår i: Advances in Building Energy Research, ISSN 1751-2549, E-ISSN 1756-2201, Vol. 17, nr 5, s. 578-604Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigates the feasibility of using only corner impinging jet ventilation (CIJV) for heating and cooling a medium-sized office space with two occupants while maintaining adequate indoor thermal comfort and air quality compared to traditional mixing ventilation systems. This study examines what impact various outdoor temperatures, ranging from −15°C to 25°C, have on an office environment in terms of indoor thermal comfort and air quality. Three different workspace positions were evaluated. The results show that the CIJV system meets the ASHRAE thermal comfort standards for all three positions. In terms of indoor air quality, CIJV performs better than traditional mixing systems, with improved mean age of air and ACE values. This study concludes that CIJV can be used both close and far away from the supply inlets and still provide adequate indoor thermal comfort and air quality during both cooling and heating season.

    Fulltekst (pdf)
    fulltext
  • 24.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Larsson, Ulf
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Karimipanah, Taghi
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Experimental Investigation of Ventilation Performance of Different Air Distribution Systems in an Office Environment: Heating Mode2019Inngår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 10, artikkel-id 1835Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A vital requirement for all-air ventilation systems are their functionality to operate both in cooling and heating mode. This article experimentally investigates two newly designed air distribution systems, corner impinging jet (CIJV) and hybrid displacement ventilation (HDV) in comparison against a mixing type air distribution system. These three different systems are examined and compared to one another to evaluate their performance based on local thermal comfort and ventilation effectiveness when operating in heating mode. The evaluated test room is an office environment with two workstations. One of the office walls, which has three windows, faces a cold climate chamber. The results show that CIJV and HDV perform similar to a mixing ventilation in terms of ventilation effectiveness close to the workstations. As for local thermal comfort evaluation, the results show a small advantage for CIJV in the occupied zone. Comparing C2-CIJV to C2-CMV the average draught rate (DR) in the occupied zone is 0.3% for C2-CIJV and 5.3% for C2-CMV with the highest difference reaching as high as 10% at the height of 1.7 m. The results indicate that these systems can perform as well as mixing ventilation when used in offices that require moderate heating. The results also show that downdraught from the windows greatly impacts on the overall airflow and temperature pattern in the room.

    Fulltekst (pdf)
    fulltext
  • 25.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Yamasawa, Haruna
    Osaka University, Japan..
    Kobayashi, Tomohiro
    Osaka University, Japan..
    Karimipanah, Taghi
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Energy saving, indoor thermal comfort and indoor air quality evaluation of an office environment using corner impinging jet ventilation2023Inngår i: Developments in the Built Environment, ISSN 2666-1659, Vol. 15, artikkel-id 100179Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The performance of a corner based impinging jet ventilation system (CIJV) in an office environment was evaluated numerically. The evaluation was done both in terms of the local thermal comfort and the local indoor air quality. Three different inlet configurations were tested for a range of outdoor temperatures that included both winter and summer conditions. In terms of indoor air quality, the results showed that CIJV performed better than a traditional mixing system. The study also revealed that CIJV creates a stronger temperature stratification in summertime compared to wintertime. When evaluating the energy saving potential the results showed a possible reduction of 7% for the ventilation flowrate when the outdoor temperatures were between -15 °C and -5 °C, 8 % when the outdoor temperatures were between 0 °C and 10 °C and 9 % when the outdoor temperatures were between 15 °C and 25 °C.

    Fulltekst (pdf)
    fulltext
  • 26.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Choonya, Gasper
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Experimental Evaluation of the Ventilation Effectiveness of Corner Stratum Ventilation in an Office Environment2019Inngår i: Buildings, E-ISSN 2075-5309, Vol. 9, nr 7, artikkel-id 169Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An experimental study was conducted in a room resembling an office in a laboratory environment. The study involved investigating the ability of corner-placed stratum ventilation in order to evaluate the ventilation’s effectiveness and local thermal comfort. At fixed positions, the air temperature, air velocity, turbulence intensity, and tracer gas decay measurements were carried out. The results show that corner-placed stratum ventilation behaves very similar to a mixing ventilation system when considering air change effectiveness. The performance of the system was better at lower supply air flow rates for heat removal effectiveness. For the heating cases, the draught rates were all very low, with the maximum measured value of 12%. However, for the cooling cases, the maximum draught rate was 20% and occurred at ankle level in the middle of the room.

    Fulltekst (pdf)
    fulltext
  • 27.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Mattsson, Magnus
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Boström, Hanna
    Lindelöw, Hanna
    Assessment of Thermal Comfort and Air Quality in Office Rooms of a Historic Building: A Case Study in Springtime in Continental Climate2023Inngår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 1, artikkel-id 156Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the most important aspects of working in an office environment is ensuring that the space has optimal thermal comfort and an indoor environment. The aim of this research is to investigate the thermal comfort and indoor climate in three office rooms located at one of the campus buildings at the University of Gävle, Sweden. The evaluated period is in the month of April during springtime. During this period, parameters such as temperature, relative humidity, CO2, supply air flow rate, and room air velocities are measured on site. The results of the measurement show that the indoor temperature is on average lower in the rooms facing north, at 21–23.5 °C, compared to the rooms facing south, which reach high temperatures during sunny days, up to 26 °C. The results also show that the ventilation air supply rate is lower than the requirement for offices in two of the office rooms. The ACH rate is also low, at ≈ 1 h−1 for all the rooms, compared to the required levels of 2–4 h−1. The CO2 levels are within the recommended values; on average, the highest is in one of the south-facing rooms, with 768 ppm, and the maximum measured value is also in the same room, with 1273 ppm for a short period of time.

    Fulltekst (pdf)
    fulltext
  • 28.
    Amiri, Shahnaz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energiteknik. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Economic and Environmental Benefits of CHP-based District Heating Systems in Sweden2013Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

  • 29.
    Amiri, Shahnaz
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energiteknik. 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 system2013Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 49, s. 242-249Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 30.
    Amiri, Shahnaz
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Weinberger, Gottfried
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Increased cogeneration of renewable electricity through energy cooperation in a Swedish district heating system - A case study2018Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 116, s. 866-877Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 31.
    Amunarriz Ollokiegi, Endika
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Electric heated windows: thermal comfort and energy use aspects2013Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    FINAL REPORT
  • 32.
    Andersen, Niklas
    et al.
    Energi Funktion Komfort Skandinavien AB, Nacka, Sweden.
    Eriksson, Ola
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöteknik.
    Hillman, Karl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöteknik.
    Wallhagen, Marita
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöteknik.
    Wind turbines’ end-of-life: Quantification and characterisation of future waste materials on a national level2016Inngår i: Energies, E-ISSN 1996-1073, Vol. 9, nr 12, artikkel-id 999Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 33.
    Andersson, David
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Olsson, Philip
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Hur kan en skola med högre energianvändning än det svenska genomsnittet energieffektiviseras?: Energikartläggning2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Europeiska unionen som helhet är en av de största energianvändarna och har en av världens största utsläpp av växthusgaser. För att minska globala uppvärmningen har mål sats upp för att medeltemperaturen på jorden inte ska öka mer än 2 grader sen förindustrielltid. Närmare 40 % av Sveriges totala energianvändning kommer från bostads- och servicesektorn detta i samband med att 2020-målen närmar sig bidrar till att energieffektiviseringar i byggnader blir allt mer essentiellt. Energikartläggningar är ett verktyg för att bestämma vad som har stört energibesparingspotential innan effektiviseringsåtgärder sker.

    Examensarbetet inkluderar en energikartläggning av Trödje skola som förvaltas av Gavlefastigheter. Arbetet är utfört med simuleringsverktyget IDA Indoor Climate and Energy. IDA ICE användes för att modulera den befintliga byggnaden där all data för skolan inkluderades. Rapportens vision är att undersöka hur mycket energi som är möjlig att spara genom energibesparingsåtgärder samt vilken åtgärd som är effektivast.

    Energibesparingspotentialen i skolan är hög, skolan använder 42,6 kWh/m2år mer än genomsnittet för Gavlefastigheters skolor vilket motsvarar 21 %. Resultaten visar att skolans komplexitet samt att påbyggnationen även kallad paviljongen är en stor faktor till att energianvändningen är hög. Skolans energianvändning har en potential att minska med 17 % vilket inte motsvarade det uppsatta 25 % - målet med arbetet. Arbetet visar att störst besparingspotential finns via byte av fönster och värmeväxlare i ventilationssystemet men även att de åtgärder som antas ge störst besparing inte alltid är effektivast.

    Fulltekst (pdf)
    fulltext
  • 34.
    Andersson, Harald
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Moshfegh, Bahram
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Linköpings universitet.
    A numerical and experimental investigation of a confluent jets ventilation supply device in a conference room2022Inngår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 5, artikkel-id 1630Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, confluent jets ventilation (CJV) supply devices with three different nozzle arrays (1 × 19, 2 × 19, 3 × 19) were investigated both numerically and experimentally at two different airflow and supply air temperature set-ups. The performance of the CJV supply devices was investigated concerning thermal comfort, indoor air quality (IAQ), and heat removal effectiveness in a conference room environment. A comparison between the experimental and numerical results showed that the v2−f model had the best agreement out of the investigated turbulence models. The numerical results showed that the size of the array had a great impact both on near-field development and on the conditions in the occupied zone. A larger array with multiple rows and a lower momentum conserved the inlet temperature and the mean age of the air better than a single-row array with a higher momentum. A larger array with multiple rows had a higher IAQ and a greater heat removal effectiveness in the occupied zone because the larger array conserved the mean age of air better and the buoyancy driven flow was slightly better at removing the heat. Because of the lower inlet velocities, they also had lower velocities at ankle level, which decreased the risk of draft and thermal discomfort.

    Fulltekst (pdf)
    fulltext
  • 35.
    Andersson, Harald
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Moshfegh, Bahram
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Energy-Saving Measures in a Classroom Using Low Pressure Drop Ceiling Supply Device: A Field Study2016Inngår i: 2016 ASHRAE Winter Conference Papers, ASHRAE, 2016Konferansepaper (Fagfellevurdert)
    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.

  • 36.
    Andersson, Kjell
    et al.
    School for Forest Management, Faculty of Forest Sciences, Swedish University of Agriculture.
    Angelstam, Per
    School for Forest Management, Faculty of Forest Sciences, Swedish University of Agriculture / Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences.
    Brandt, S. Anders
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för datavetenskap och samhällsbyggnad, Samhällsbyggnad.
    Axelsson, Robert
    County Administrative Board Västmanland.
    Bax, Gerhard
    Limited GIS skills hamper spatial planning for green infrastructures in Sweden2022Inngår i: Geografiska Notiser, ISSN 0016-724X, Vol. 80, nr 1, s. 16-35Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    The term green infrastructure captures the need to conserve biodiversity and to sustain landscapes’ different ecosystem services. Maintaining green infrastructures through protected areas, management and landscape restoration requires knowledge in geography, spatial data about biophysical, anthropogenic and immaterial values, spatial comprehensive planning, and thus geographical information systems (GIS). To understand land use planning practices and planning education regarding GIS in Sweden we interviewed 43 planners and reviewed 20 planning education programmes. All planners used GIS to look at data but did not carry out spatial analyses of land covers. BSc programmes included more GIS than MSc programmes but very few taught analyses for spatial planning. As key spatial planning actors, municipalities’ barriers and bridges for improved GIS use for collaborative learning about green infrastructures are discussed. A concluding section presents examples of how GIS can support spatial planning for green infrastructures.

    Fulltekst (pdf)
    Limited-GIS-skills-hamper-spatial-planning
  • 37.
    Andersson, Maria
    et al.
    Department of Psychology, University of Gothenburg, Göteborg, Sweden .
    Eriksson, Ola
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Teknisk miljövetenskap.
    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 Settings2012Inngår i: Sustainability, E-ISSN 2071-1050, Vol. 4, nr 6, s. 1292-1308Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 38.
    Andersson, Martin
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Berge, Nils
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Energi- och miljökonsekvenser vid energieffektivisering av belysning och installation av solceller på Nacka Forum i Stockholm2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Energianvändningen ökar världen över och på grund av hotet om en global uppvärmning diskuteras det alltmer hur användandet skall minskas samtidigt som fler hållbara energikällor efterfrågas. Bostad- och service sektorn står för ca 40 % den totala energianvändningen i världen där energin främst kommer från fossila källor.För att minska miljöpåverkan har EU satt upp klimatmål som bland annat innebär att energianvändandet ska minskas med 20 % till 2020 räknat från år 2008. En viktig del för att uppnå detta mål är genom energieffektiviseringar.Syftet med denna fallstudie var att finna lösningar för vilket Nacka Forums elkostnader kunde sänkas. Arbetet begränsade sig till de utrymmen som Unibail-Rodamco själva ansvarar över såsom servicegångar och allmänna utrymmen i gallerian. Genom en litteraturstudie erhölls idéer om tänkbara energieffektiviseringsåtgärder som lämpar sig för denna typ av byggnad. Där framgick också att köpcentrum använder över lag mycket energi och framförallt elenergi där belysning är en av de större lasterna.Ett allt mer förekommande inslag hos fastigheter idag är solceller som både bidrar till minskade elkostnader samtidigt som efterfrågan på fossilenergi minskar. Då gallerian tillsynes verkade ha goda förutsättningar undersöktes möjligheterna till om detta var något att rekommendera. En anläggning på 100 kWp med en takyta på 921 m2 beräknades ge en energibesparing på 93 534 kWh/år och författarna konstaterar att detta vore en bra lösning samt att en än större toppeffekt bör undersökas.Delar av byggnaden upplevdes vara överbelyst och mätningar av belysstyrkan utförde i dessa områden. Resultatet visade vid de flesta mätpunkterna att så var fallet och det föreslogs att reglera belysningen efter dagsljuset.Vid inventering av den befintliga belysningen togs förslag på en energieffektivare lösning fram där LED-belysning ansågs som det bästa alternativet. Byte av endast ljuskällorna skulle i teorin göra en bra besparing men då de befintliga armaturerna ansågs vara i slutet av sin tekniska livslängd skulle ett byte av dessa även behöva göras inom de kommande åren. Därför förslås här ett byte av både armaturer och ljuskällor vilket skulle ge en energibesparing på 544,4 MWh/år och en återbetalningstid på 3,3 år. Denna energibesparing minskar även potentiellt de globala koldioxidutsläppen med 218 ton/år. Oavsett förslag så minskas både energianvändningen och miljöpåverkan med minst 50 %.Belysningen i en butik undersöktes och det konstaterades att de effektkrav på belysning som i nuläget ställs på butikerna är för låga. Trots att butiken hade stora problem med den termiska komforten till följd av just detta underskreds de satta 50 W/m2 med marginal. Det för lågt satta kravet hämmar här energieffektiviseringar och bidrar även med onödigt värmetillskott.

    Fulltekst (pdf)
    fulltext
  • 39.
    Antón, Raúl
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för energi- och maskinteknik. Royal Institute of Technology, Stockholm, Sweden; TECHUN, University of Navarra, San Sebastián, Spain.
    Jonsson, Hans
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för energi- och maskinteknik. Royal Institute of Technology, Stockholm, Sweden.
    Moshfegh, Bahram
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för energi- och maskinteknik.
    Detailed CFD modelling of EMC screen for radio base stations: A conjugate heat transfer problem2007Inngår i: International Journal of Heat Exchangers, ISSN 1524-5608, Vol. 8, nr 1, s. 95-116Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objective of this paper is to perform an experimental as well as CFD investigations of the conjugate heat transfer problem in a sub-rack slot model. A steady-state three-dimensional detailed model, which serves as the most accurate representation of the model, was used in order to evaluate the details of the airflow paths and temperature field. A general model that covers a considerable range of velocities, screen porosities and heat fluxes was validated experimentally by wind tunnel measurements. The result shows that the RNG k-ε model used with correct y+ and mesh strategy accurately predicts the temperature field. The average temperature deviation at several locations is less than 4% compared to experimental data. The influence of the velocity, screen porosity, heat flux and presence of the EMC screen on the PCB temperature field is commented. © 2007 R.T. Edwards, Inc.

  • 40.
    Arana, Eneko
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Energy improvement options for a small-scale brewery: a literature study2022Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    In the age of technology and development in which we live nowadays, it is inevitable to realise that this so-called progress is translated into pollution, damage to the environment and abuse of energy and fossil fuels. The companies and factories that produce the goods we need, use a lot of energy and pollute in massive ways, posing dilemmas such as how to make these companies more energetically and environmentally efficient, with the aim of decreasing the emissions and energy use. This literature review proposes a compilation and update of suggestions made to microbreweries after undergoing an energy audit, in an attempt to make these companies more energy-efficient, competitive, economical and sustainable. The information has been obtained by searching peer-reviewed articles in different databases and re-arranged in this article into sections on energy efficiency measures, waste treatment options and environmental impact. Several studies have been carried out on improving efficiency and trying to decrease the environmental impact of beer production processes. The main issues found during the process are energy efficiency and the generated wastewater. Both problems could be solved either by using an internal boiler that would generate less waste, applying renewable energies or by treating the residues in bioreactors, a field that needs further study. The choice of packaging material will be influenced by customer preferences and material recycling, being glass bottles and aluminium cans the most popular choices. 

    Fulltekst (pdf)
    fulltext
  • 41.
    Aranaga Decori, Pierre Ander
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap.
    Implementation of energy recovery and storage systems in cranes in the Port of Gävle2020Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Container traffic in seaports around the world in constantly increasing, with energy costs being a significant part of the total costs. The container terminal (CT) of the Port of Gävle, the largest in the east coast of Sweden, is not an exception to this. With traffic growing annually, a new terminal will be opened in the following years, adding three more ship-to-shore (STS) cranes to the two existing ones, and six electric rubber tyred gantry (eRTG) cranes. Therefore, it is highly important to strengthen energy efficiency measures, reducing the energy consumption and the costs associated with it. This is why the aim of this report is to analyse whether implementing energy storage systems in the cranes of the container terminal Port of Gävle can contribute to reduce electricity costs by recovering energy when braking lowering containers, and by shaving power peaks. After a literature review of current energy recovery and storage options, this work presents three solutions: two alternatives for the current situation with two ship-to-shore (STS) cranes, and a third solution to be implemented in the three future STS cranes to be installed, which can also be beneficial for any other crane in the terminal. According to the made calculations, the three alternatives can reduce considerable energy consumption, and they are highly profitable. However, those solutions are a preliminary study and more work needs to be done to determine the exact profitability and technical system details. This work has been done in collaboration with the Port of Gävle and Yilport, the company operating the container terminal.

    Fulltekst (pdf)
    Implementation of energy recovery and storage systems in cranes in the Port of Gävle
  • 42.
    Archakis, Viktor
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    The Design of a Passive House2018Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    About 25 % of the total buildings in the European Union have been categorized as ”old buildings”. Followed the recent strickt rules for carbon emissions reduction, each house has to approximetely cut 20 % of CO2 by 2020. Countries like England, have taken the issue very seriously and planning to reduce the carbon emissions by 30 % until the end of 2020 and by an extra 80 % by 2050 (Francis Moran, 2014). The aim of the report is to present how a traditional house can be retroffited into a passive house and also to identify the key points that every passive house should have. For the purpose of the project an avtual house, based in Gävle, was provided and all the simulations are based on actual data. The initial design of the house which was used for the simulation and the 3D design, was provided by the house owner. The building was built in 1953, information regarding the current insulation of the house was provided by the owner as well. For the simulations and the 3D design a software know as IDA ICE was used, license and access to the software were given by the University of Gävle. The report simulates the current house and compares the results with two possible scenarios that are reducing the energy demand of the house. Furthermore, the possible ways and tools that could be used to reduce the energy demand of the house and cost estimation for the retrofitting is available in the paper.The first simulations were occured on the actual house, the first retrofitting package introduces new simulations based on new insulation materials, like wood and cement, that are placed mainly on the roof and on the outer walls. Also, the thickness have changed, thus the new insulations are thicker.Moreover, the second and final retrofitting package, introduces an HVAC system, which is a standard system. The aim is to achieve further energy demand reductions and prove that simple and basic changes can improve the quality of living and reduce CO2 emissions.After the completition of the first analysis, a reduction equal to 60 % and after the addition of the HVAC a further 20 % reduction achieved.

    Fulltekst (pdf)
    fulltext
  • 43.
    Arcos Usero, Lucía
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Analysis and improvements of outdoor hot benches in Gävle2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    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.

    Fulltekst (pdf)
    Thesis project Lucía Arcos
  • 44.
    Arfan, Muhammad
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Utilization of local bioresources for transport fuels - System analysis for decision support2023Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis presents a comprehensive system analysis of the utilization of biowaste and forest industry residues to produce transportation fuels. It explores various aspects such as the constraints to the production system’s value chain development, the utilization of the geographical proximity of biofuel technology innovation system components, environmental impacts, and economic costs. The primary goal is to establish a knowledge base that can aid regional policymakers and decision-makers in formulating informed policies for the efficient management of local bioresources for transport fuel production. By addressing these aspects, the study seeks to contribute to the wider discourse on efficient local bioresource management and transition to a low-carbon economy. The focused bioresources in this thesis are municipal biowaste and forest industry residues (i.e., sawdust, black liquor, crude tall oil, and fiber waste of the pulp and paper industry). The study focuses on three systems: i) biowaste to biogas for transport, ii) biowaste and sawdust to hydrogen, and iii) forest industry residues to liquid biofuels for transport.

    The biofuel policy instruments in Sweden have proven to be effective in introducing alternative transport fuels, particularly in big cities or urban areas. The results of the biowaste to biogas value chain analysis show that development in the Gävleborg region is stagnated throughout the value chain compared to the national average. This stagnation is mainly attributed to local geodemographic factors. The identified obstacles to development include a lack of regional political agreement regarding the use of biogas as a viable transport fuel, insufficient connectivity and communication among the various regional actors and stakeholders, and a limited understanding among stakeholders of the potential and socio-economic impacts of biogas. 

    The environmental and economic assessment of hydrogen production from biowaste and sawdust is performed from a life cycle perspective, using SimaPro LCA software and CML-IA, 2001 impact assessment method. Economic analysis includes capital and operational expenditures and monetization cost of life cycle environmental impacts. The results show that hydrogen production from biowaste has a higher global warming, photochemical oxidant, and freshwater eutrophication potential than sawdust. Biowaste conversion to hydrogen performs far better in ozone depletion, terrestrial ecotoxicity, abiotic depletion-fossil, abiotic depletion, human toxicity, and freshwater ecotoxicity potential. The fossil energy inputs in biogas and pyrolysis oil reforming, emissions from the digestate treatment, storage, and utilization as bio-fertilizer are the main contributing processes to the overall environmental impacts of biowaste and sawdust conversion to hydrogen. 

    The sensitivity analysis of the LCA results indicates that feedstock to biogas/pyrolysis oil yield ratio and the type of energy source for the reforming process can significantly influence the results, particularly climate change, abiotic depletion, and human toxicity. 

    The life cycle cost (LCC) analysis reveals that the production of hydrogen from biowaste exhibits a lower cost compared to sawdust. This significant cost reduction in the biowaste case can be attributed to lower variable operating expenses (OPEX), primarily due to the price of the biowaste itself. Whereas, in the sawdust case, the feedstock contributes the highest percentage (54%) to the system's OPEX, indicating that variable OPEX is highly sensitive to sawdust prices. Additionally, the capital investment required for the biowaste case was 50% lower, which further contributes to the lower overall LCC compared to the sawdust case.

    The results of forest industry residues to liquid biofuel technology development and the utilization of system components in geographical proximity indicate that geographical proximity can significantly influence the system’s structural growth, trajectory, and development pace. An adapted version of the technological innovation system (TIS) framework was operationalized with the lens of geographical proximity utilization of the system components to the technology development and diffusion. The method of data acquisition involved document analysis and interviews with subsystem actors. The study found that the development of the system is hampered by competition between technologies and low utilization of geographical proximity of the system components, which was partly attributed to a lack of network among subsystem actors and with the national TIS structure. 

    Bioresources in Gävleborg are present in substantial amounts, particularly biowaste from agriculture, the food industry, and households, as well as biomass from the forest industry, which have the potential to be utilized for transport fuel production. However, the evolution of their utilization to power transportation in Gävleborg has been delayed in comparison to several other regions in Sweden. In the case of the technology development of forest industry residue-based transport fuels, the utilization of geographical proximity of artefacts and institutions has played a crucial role. Significant strides have been accomplished in diverse technology domains. However, these advancements have faced obstacles, partially due to the rivalry among system actors aiming to secure a competitive edge in acquiring both knowledge and capital resources and the underutilization of the geographical proximity of actors and industry networks. 

    Based on these research findings, recommendations are provided to support policy and strategy aiming to enhance the utilization of local bioresources for transportation fuels sustainably and cost-effectively with increased local benefits. For example, the study recommends addressing the identified local political, communication, and networking issues, along with integrating regional geodemographic conditions into national biofuel policies and measures. By addressing identified challenges, the Gävleborg region can overcome the stagnation in bioresource to transportation fuel technological systems development and leverage its significant potential.

    This thesis adds valuable insights to the sustainability transition literature about the environment, economy, and the geography of innovation processes. The findings highlight the need for policy interventions to foster collaboration, coordination, and knowledge sharing among stakeholders, as well as support for the development and commercialization of emerging technologies, including forest-based transport fuel technologies. The analysis of cost and environmental impacts of bioresource utilization for hydrogen production provides insights into the potential trade-offs and benefits of different feedstocks and impact categories. The study provides important input for policy and strategy development towards a more sustainable and cost-effective use of local bioresources for transport fuel production in Gävleborg. This study can also serve as a valuable reference for researchers, policymakers, and stakeholders interested in the sustainable utilization of renewable resources for biofuel production, contributing to the advancement of knowledge in this critical area.

    Fulltekst (pdf)
    fulltext
  • 45.
    Arfan, Muhammad
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Eriksson, Ola
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Wang, Zhao
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Soam, Shveta
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Life cycle assessment and life cycle costing of hydrogen production from biowaste and biomass in Sweden2023Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 291, artikkel-id 117262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, an environmental and economic assessment of hydrogen production from biowaste and biomass is performed from a life cycle perspective, with a high degree of primary life cycle inventory data on materials, energy, and investment flows. Using SimaPro LCA software and CML-IA, 2001 impact assessment method, ten environmental impact categories are analyzed for environmental analysis. Economic analysis includes capital and operational expenditures and monetization cost of life cycle environmental impacts. The hydrogen production from biowaste has a high climate impact, photochemical oxidant, and freshwater eutrophication than biomass while it performs far better in ozone depletion, terrestrial ecotoxicity, abiotic depletion-fossil, abiotic depletion, human toxicity, and freshwater ecotoxicity. The sensitivity analysis of LCA results indicates that feedstock to biogas/pyrolysis-oil yields ratio and the type of energy source for the reforming process can significantly influence the results, particularly climate change, abiotic depletion, and human toxicity. The life cycle cost (LCC) of 1 kg hydrogen production has been accounted as 0.45–2.76 € with biowaste and 0.54–3.31 € with biomass over the plant's lifetime of 20 years. From the environmental impacts of climate change, photochemical oxidant, and freshwater eutrophication hydrogen production from biomass is a better option than biowaste while from other included impact categories and LCC perspectives it’s biowaste. This research contributes to bioresources to hydrogen literature with some new findings that can be generalized in Europe and even globally as it is in line with and endorse existing theoretical and simulation software-based studies.

    Fulltekst (pdf)
    fulltext
  • 46.
    Arfan, Muhammad
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Hillman, Karl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    The geography of technological innovation systems - The case of forest-based biofuels in a Swedish region2024Inngår i: Innovation and Green Development, E-ISSN 2949-7531, Vol. 3, nr 2, artikkel-id 100122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Geographical proximity exerts a substantial influence on structural evolution, developmental trajectory, and pace of sociotechnical system growth. This study explores this aspect within the context of the development of forest biomass-based biofuel technology, employing a Technological Innovation System (TIS) framework with the lens of geographical proximity utilization of system components. The research employed a combination of document analysis and interviews with key system stakeholders as data collection methods. The analysis reveals that the close geographical proximity of the system components and technologies, encompassing both technical aspects and sectors, did not result in synergetic effects, in contrast to prior TIS research findings. Rather than fostering collaboration, it has engendered a competitive dynamic, partially driven by actors vying for knowledge leads and funding from both regional and national agencies. Consequently, the potential benefits of geographical proximity of system components remain largely untapped. In light of these results, this study offers practical recommendations for exploiting untapped opportunities, advocating for more strategic use of geographical proximity to foster system technology development and enhance its role in national TIS development. This case study enriches sustainability transition literature by providing valuable insights into the role of geographical proximity in innovation processes.

    Fulltekst (pdf)
    fulltext
  • 47.
    Arfan, Muhammad
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Wang, Zhao
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Soam, Shveta
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Eriksson, Ola
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Biogas as a transport fuel—a system analysis of value chain development in a Swedish context2021Inngår i: Sustainability, E-ISSN 2071-1050, Vol. 13, nr 8, artikkel-id 4560Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biofuels policy instruments are important in the development and diffusion of biogas as a transport fuel in Sweden. Their effectiveness with links to geodemographic conditions has not been analysed systematically in studying biogas development in a less urbanised regions, with high potential and primitive gas infrastructure. One such region identified is Gävleborg in Sweden. By using value chain statistics, interviews with related actors, and studying biofuels policy instruments and implications for biogas development, it is found that the policy measures have not been as effective in the region as in the rest of Sweden due to different geodemographic characteristics of the region, which has resulted in impeded biogas development. In addition to factors found in previous studies, the less-developed biogas value chain in this region can be attributed particularly to undefined rules of the game, which is lack of consensus on trade-off of resources and services, unnecessary competition among several fuel alternatives, as well as the ambiguity of municipalities’ prioritization, and regional cultural differences. To strengthen the regional biogas sector, system actors need a strategy to eliminate blocking effects of identified local factors, and national policy instruments should provide mechanisms to process geographical conditions in regulatory, economic support, and market formation.

    Fulltekst (pdf)
    fulltext
  • 48.
    Argume, A.
    et al.
    Universidad Privada de Tacna, Peru.
    Coaguila, R.
    Universidad Católica de Santa María, Peru.
    Yanyachi, P. R.
    Universidad Nacional San Agustin de Arequipa, Peru.
    Chilo, José
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektroteknik, matematik och naturvetenskap, Elektronik.
    NOAA Image Data Acquisition to Determine Soil Moisture in Arequipa - Perú2021Inngår i: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 68, nr 8, s. 1933-1936Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In recent years, irrigations have been built on dry areas in Majes-Arequipa. Over time, the irrigations water forms moist areas in lower areas, which can have positive or negative consequences. Therefore, it is important to know in advance where the water from the new irrigation will appear. The limited availability of real-time satellite image data is still a hindrance to some applications. Data from environmental satellites NOAA (National Oceanic and Atmospheric Administration) are available fee and license free. In order to receive data, users must obtain necessary equipment. In this work we present a satellite data acquisition system with an RTL SDR receiver, two 137-138 Mhz designed antennas, Orbitron, SDRSharp, WXTolmag and MatLab software. We have designed two antennas, a Turnstile Crossed dipole antenna with Balun and a quadrifilar helicoidal antenna. The antennas parameter measurements show very good correspondence with those obtained by simulation. The RTL SDR RTL2832U receiver, combined with our antennas and software, forms the system for recording, decoding, editing and displaying Automatic Picture Transmission (APT) signals. The results show that the satellite image receptions are sufficiently clear and descriptive for further analysis.

  • 49.
    Arnaiz Remiro, Lierni
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Modelling and assessment of energy performance with IDA ICE for a 1960's Mid-Sweden multi-family apartment block house2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    The present thesis has been carried out during the spring of 2017 on behalf of Gavlegårdarna AB. This is a public housing company in Gävle (Sweden) which is a large energy consumer, over 200 million SEK per year, and has the ambitious goal of reduce its energy consumption by 20 % between 2009 and 2020. Many multi-family apartment blocks were built during the "million programme" in the 60’s and 70’s when thermal comfort was the priority and not the energy saving. Nevertheless, this perspective has changed and old buildings from that time have been retrofitted lately, but there are many left still. In fact, one of these buildings will be retrofitted in the near future so a valid model is needed to study the energy saving measures to be taken. The aim of this thesis is to get through a calibration process to obtain a reliable and valid model in the building simulation program IDA ICE 4.7.1. Once this has been achieved it will be possible to carry out the building’s energy performance assessment. IDA ICE has shown some limitations in terms of thermal bridges which has accounted for almost 15 % of total transmission heat losses. For this reason, it is important to make a detailed evaluation of certain joints between elements for which heat losses are abundant. COMSOL Multiphysics® finite element software has been used to calculate these transmittances and then use them as input to IDA ICE to carry out the simulation.

    Through an evidence-based methodology, although with some sources of uncertainty, such as, occupants’ behaviour and air infiltration, a valid model has been obtained getting almost the same energy use for space heating than actual consumption with an error of 4% (Once the standard value of 4 kWh/m2 for the estimation of energy use in apartments' airing has been added). The following two values have been introduced to IDA ICE: household electricity and the energy required for heating the measured volume of tap water from 5 °C to 55 °C. Assuming a 16 % of heat losses in the domestic hot water circuit, which means that part of the heat coming from hot water heats up the building. This results in a lower energy supply for heating than the demanded value from IDA ICE. Main heat losses have been through transmission and infiltration or openings. Windows account 11.4 % of the building's envelope, thus the losses through the windows has supposed more than 50 % of the total transmission losses. Regarding thermal comfort, the simulation shows an average Predicted Percentage of Dissatisfied (PPD) of 12 % in the worst apartment. However, the actual value could be considerably lower since the act of airing the apartments has not been taken into account in the simulation as well as the strong sun's irradiation in summer which can be avoided by windows shading. So, it could be considered an acceptable level of discomfort. To meet the National Board of Housing Building and Planning, (Boverket) requirements for new or rehabilitated buildings, several measures should be taken to improve the average thermal transmittance and reduce the specific energy use. Among the energy saving measures it might be interesting replace the windows to 3 pane glazing, improve the ventilation system to heat recovery unit, seal the joints and intersections where thermal bridges might be or add more insulation in the building’s envelope.

    Fulltekst (pdf)
    fulltext
  • 50.
    Arnal Estelles, Paloma
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Hand drying in public places: Paper towel vs warm air blower, which is best from an energy and environmental point of view.2023Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    fulltext
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