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  • 1.
    aala, elsafei
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Numerical study of flow development in the near and intermediate field of a free round jet2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
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  • 2.
    Abd Nikooie Pour, Mina
    et al.
    Linköpings universitet.
    Algergawy, Alsayed
    University Jena, Germany.
    Amardeilh, Florence
    Elzeard.co, Paris, France.
    Amini, Reihaneh
    Data Semantics (DaSe) Laboratory, Kansas State University, United States.
    Fallatah, Omaima
    Information School, University Of Sheffield, Sheffield, United Kingdom.
    Faria, Daniel
    Faculdade De Cîencias, Universidade De Lisboa, Lasige, Portugal.
    Fundulaki, Irini
    Institute Of Computer Science-FORTH, Heraklion, Greece.
    Harrow, Ian
    Pistoia Alliance Inc., United States.
    Hertling, Sven
    University Of Mannheim, Germany.
    Hitzler, Pascal
    Data Semantics (DaSe) Laboratory, Kansas State University, United States.
    Huschka, Martin
    Fraunhofer Institute For High-Speed Dynamics, EMI, Germany.
    Ibanescu, Liliana
    AgroParisTech, Umr MIA-Paris/INRAE, France.
    Jiménez-Ruiz, Ernesto
    University Of London, City, United Kingdom; Department Of Informatics, University Of Oslo, Norway.
    Karam, Naouel
    Fraunhofer Fokus, Berlin, Germany; Institute For Applied Informatics (InfAI), University Of Leipzig, Germany.
    Laadhar, Amir
    Department Of Computer Science, Aalborg University, Denmark.
    Lambrix, Patrick
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköpings universitet.
    Li, Huanyu
    Linköpings universitet.
    Li, Ying
    Linköpings universitet.
    Michel, Franck
    University Ĉote d'Azur, CNRS, Inria, France.
    Nasr, Engy
    University Of Freiburg, Freiburg Galaxy Team, Germany.
    Paulheim, Heiko
    University Of Mannheim, Germany.
    Pesquita, Catia
    Faculdade De Cîencias, Universidade De Lisboa, Lasige, Portugal.
    Portisch, Jan
    University Of Mannheim, Germany.
    Roussey, Catherine
    Inrae Centre Clermont-ARA, Laboratoire Tscf, France.
    Saveta, Tzanina
    Institute Of Computer Science-FORTH, Heraklion, Greece.
    Shvaiko, Pavel
    Trentino Digitale SpA, Trento, Italy.
    Splendiani, Andrea
    Pistoia Alliance Inc., United States.
    Trojahn, Cássia
    Irit and Université Toulouse II, Toulouse, France.
    Vatascinová, Jana
    Prague University Of Economics And Business, Czech Republic.
    Yaman, Beyza
    Adapt Centre, Dublin City University, Ireland.
    Zamazal, Ondrej
    Prague University Of Economics And Business, Czech Republic.
    Zhou, Lu
    Data Semantics (DaSe) Laboratory, Kansas State University, United States.
    Results of the Ontology Alignment Evaluation Initiative 20212021In: Proceedings of the 16th International Workshop on Ontology Matching co-located with the 20th International Semantic Web Conference (ISWC 2021), Virtual conference, October 25, 2021 / [ed] Shvaiko P., Euzenat J., Jimenez-Ruiz E., Jimenez-Ruiz E., Hassanzadeh O., Trojahn C., CEUR-WS.org , 2021, p. 62-108Conference paper (Refereed)
    Abstract [en]

    The Ontology Alignment Evaluation Initiative (OAEI) aims at comparing ontology matching systems on precisely defined test cases. These test cases can be based on ontologies of different levels of complexity and use different evaluation modalities (e.g., blind evaluation, open evaluation, or consensus).The OAEI 2021 campaign offered 13 tracks and was attended by 21 participants.This paper is an overall presentation of that campaign. 

  • 3.
    Abd Nikooie Pour, Mina
    et al.
    Linköping University.
    Li, Huanyu
    Linköping University.
    Armiento, Rickard
    Linköping University.
    Lambrix, Patrick
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköping University.
    A First Step Towards a Tool for Extending Ontologies2021In: Proceedings of the Sixth International Workshop on the Visualization and Interaction for Ontologies and Linked Data: co-located with the 20th International Semantic Web Conference (ISWC 2021) / [ed] Patrick Lambrix, Catia Pesquita, Vitalis Wiens, CEUR Workshop proceedings , 2021, p. 1-12Conference paper (Refereed)
    Abstract [en]

    Ontologies have been proposed as a means towards making data FAIR (Findable, Accessible, Interoperable, Reusable). This has attracted much interest in several communities and ontologies are being developed. However, to obtain good results when using ontologies in semantically-enabled applications, the ontologies need to be of high quality. One of the quality aspects is that the ontologies should be as complete as possible. In this paper we propose a first version of a tool that supports users in extending ontologies using a phrase-based approach.  To demonstrate the usefulness of our proposed tool, we exemplify the use by extending the Materials Design Ontology.

  • 4.
    Abdul Hakim, Faisal
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Said, Shazad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    En studie av småhusentreprenader: Varför går det fel?2021Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study was to investigate the single-family home construction industry and what problems arise. Furthermore, it was intended that this study would give the public a better idea of why conflicts arise between customers and contractors and how home suppliers work to counteract these problems.

    To achieve the purpose and get answers to the research questions, we used a qualitative research method in the form of semi-structured interviews. The reason why this interview technique was applied was to give respondents the freedom to talk openly about their experiences and views. The respondents interviewed were four representatives of house suppliers, three clients, a building inspector and an inspection manager.

    The results of the interviews showed that there was a common opinion among clients and house suppliers on certain issues, but then there were also opinions that differed. The study showed that customers experience the construction of detached houses as a slow and energy-intensive process. The problems that are common in detached house contracts are that there is a difference in language and knowledge between the involved parties. This results in a lack of communication which in turn can lead to various conflicts.

    Home suppliers are aware of the problems that exist in the industry and work continuously to develop solutions. One such solution is to place great emphasis on documentation and contracts because they are the ones that are legally binding. The conclusion of this study was that good communication results in fewer misunderstandings and conflicts. Conflicts, on the other hand, cannot be completely avoided, but will always arise due to human factors. 

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  • 5.
    Abellán Guallarte, Alejandro
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Energy analysis between traditional hot water circulation system and an innovative pipe-in-pipe system2022Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    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.

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  • 6.
    Abolghasemi Moghaddam, Saman
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    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 credits / 15 HE creditsStudent thesis
    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.

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  • 7.
    Abu Sulaiman, Iyad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Ibrahim, Miran
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Framställning av dränerande bärlager från bergtäkt2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Bearing layers are used in road and building constructions as underlying soil layers to provide stability and support to the top layer that takes up the load. A normal bearing layer contains different amounts of materials such as stone, gravel, and filler. That mixture of materials contains a large amount of filler to give the product tightness and stability. Draining bearing layers usually contain less filler than ordinary bearing layers, because their purpose is to improve the drainage properties and reduce the risk of damage due to water collection.This thesis work took place at NCC's quarries in Sälgsjö and Hammarby. At NCC's rock quarry, there already is a standard bearing layer with a grain size of 0/32 and a filler content of approximately 4–5%. In this degree project, a production process has been created to obtain a drain bearing layer where the filler content is reduced to approximately 2–3%. The requirement for a draining carrier layer is 2–3% filler content and this requirement has been followed in this production process. The draining bearing layer has been produced based on a standard product with the same grain size.There are practical limitations in how the operations work and what capabilities are required. Moisture in the material has also been a limitation. In this project, work is done with freshly crushed material, which has a relatively low moisture content (1–2%). A vibration-free screen like the function of the harp has been designed and built. Then the standard product was run through the harp at different gradients and the new product was analyzed in the lab to see what filler content was achieved. A simulation test was performed using a FEM design program called Digiroad at Chalmers University of Technology in Gothenburg.The results demonstrate that the utilization of the developed models of harp screens reduces the proportion of filler in the material. Additionally, the conducted harp screen analyses confirm that the designed harp screens are effective in transforming a standard bearing layer into a draining bearing layer, which helps to prevent water accumulation under roads or buildings and thus reduces the risk of damage and problems. The efficient production process for producing draining bearing layers can be of great importance to ensure a sustainable and safe infrastructure.

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  • 8.
    Abushaqfa, Omar
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Bakero, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Materials brandförmåga för mellanväggar2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays, architects, designers and engineers pay a lot of attention to fire safety in buildings.Due to the high number of accidents, fire safety in construction is becoming increasinglyimportant.In order to use more fire-resistant material in the structure, attention was paid to the propertiesof the materials used. The material has begun to be evaluated for standard resistance and somestandard tests have been developed. Based on how long the material did not show anysignificant damage, these materials were evaluated and graded. This classification can beaccessed from Eurocodes (Svensk trä,2022).Timber was used in construction even before history was written. Since the ancient civilization,wood has been an important building material.Wood exhibits great resistance to fire due to its self-insulating property.When wood burns, it first chars to a certain depth. Then the outer charred layer acts as a barrierand suppresses the fire. This fire-extinguishing property in itself is the wood's self-insulatingproperty. (Swedish wood, 2021).Fire exposure usually occurs according to the standard fire curve that describes a fullydeveloped fire as defined in EN 1363-1. Building parts must withstand fire for a certain time,for example 60 minutes. With wooden constructions, it is possible to achieve high fire resistancewith the help of insulating material (EI). (Swedish wood, 2021).In the first part of the thesis, the properties of wood as a building material are discussed. INthe next part discusses the fire classes Br0, Br1, Br2 and Br3 for buildings. After that, the readercan learn about how a building can be divided into sections depending on its fire rating. Amaterial investigation will be done to be able to see the fire properties of certain materials thatwe will add to or remove from the wall such as extra plasterboard or insulation material withoutchanging the thickness of the wall to make them more fireproof and to be able to last longerwithout the fire spreads to the other spaces with the help of better material ability. (Swedishwood, 2021).This work also presents the theory behind wall fire sectioning in terms of materials and thevarious fire engineering solutions with some examples of calculations relating to the fireresistance of the materials, with references to the instructions in SS-EN 1995-1-2:2004/AC:2010. Finally, the results are analyzed and compared with different materials. Usingthe results of reactions of different types of materials and insulation, the fire resistance ofwooden walls can be discussed in more detail.Results show that gypsum boards combined with stone wool is the best choice of material forcreating fireproof partition walls. The results of our calculations show that double gypsumboards on each side with a thickness of 15 mm combined with stone wool with a thickness of95 mm provides fire resistance up to 109 minutes. Compared to a partition wall with a gypsumboard on each side without insulation, fire resistance is up to 48 minutes. This has beenemphasized with a study where the fire resistance has been investigated for walls, they havefound that double gypsum board combined with stone wool with the right conditions providesfire resistance up to 142 minutes. However, it is crucial for fire resistance to work that theinstallation is carried out correctly. All resulting screws must be placed correctly, there must beno holes on the gypsum boards and the number of gypsum boards and insulation thicknesstogether with the correct assembly provides better fire protection. This is based on the resultsthat have been obtained from articles, calculation during this work and from interviews withthe companies that work with requirements, manufacture and installation of fireproof partitionwalls. 

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  • 9.
    Afzali Gorouh, Hossein
    et al.
    Shahid Bahonar University of Kerman, Iran.
    Salmanzadeh, Mazyar
    Shahid Bahonar University of Kerman, Iran.
    Nasseriyan, Pouriya
    Shahid Bahonar University of Kerman, Iran.
    Hayati, Abolfazl
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cabral, Diogo
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Gomes, João
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Karlsson, Björn
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Thermal modelling and experimental evaluation of a novel concentrating photovoltaic thermal collector (CPVT) with parabolic concentrator2022In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 181, p. 535-553Article in journal (Refereed)
    Abstract [en]

    In the present study, a zero-dimensional thermal model has been developed to analyze a novel low concentration photovoltaic-thermal (CPVT) collector. The model has been developed by driving heat transfer and energy balance equations for each part of the collector and then solving all the equations simultaneously. Moreover, a Monte-Carlo ray-tracing software has been used for optical stimulations of the parabolic trough solar collector. The novel CPVT collector has been experimentally tested at Gävle University (Sweden) and the model has been validated against the experimental results. The primary energy saving equivalent to the thermal-electrical power cogeneration of the CPVT collector has been determined. The effect of glass cover removal, heat transfer fluid (HTF) inlet temperature and mass flow rate on the collector performance has been investigated. The optimum HTF mass flow rates of the collector for maximum electrical yield and overall primary energy saving were determined under specified operating conditions by considering the pump consumption. The effect of mean fluid temperature on the thermal and electrical efficiencies has been studied and the characteristic equation of the thermal efficiency has been obtained. The thermal and electrical peak efficiencies of the collector have been found to be 69.6% and 6.1%, respectively.

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  • 10.
    Ahmad, Afaq
    et al.
    Department of Civil Engineering, University of Engineering and Technology, Taxila, Rawalpindi 46600, Pakistan.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Alajarmeh, Omar
    Centre for Future Materials (CFM), School of Civil Engineering and Surveying, University of Southern Queensland, Toowoomba 4350, Australia.
    Chairman, Nida
    Department of Civil and Architectural Engineering, University of Westminster, London W1B 2HW, UK.
    Yaqub, Muhammad
    Department of Civil Engineering, University of Engineering and Technology, Taxila 47080, Pakistan.
    Investigation of Circular Hollow Concrete Columns Reinforced with GFRP Bars and Spirals2023In: Buildings, E-ISSN 2075-5309, Vol. 13, no 4, article id 1056Article in journal (Refereed)
    Abstract [en]

    Glass fiber-reinforced polymer (GFRP) reinforcements are useful alternatives to traditional steel bars in concrete structures, particularly in vertical structural elements such as columns, as they are less prone to corrosion, and impart increasing strength and endurance of buildings. There is limited research on the finite element analysis (FEA) of the structural behavior of hollow glass fiber-reinforced polymer reinforced concrete (GFRPRC) columns. The hollow portion can be used for the service duct and for reducing the self-weight of the members. Numerical analysis of the compressive response of circular hollow concrete columns reinforced with GFRP bars and spirals is performed in this study. This article aims to investigate the axial behavior of hollow GFRP concrete columns and compare it with that of solid steel reinforced concrete (RC) columns as well as hollow steel RC columns. The Abaqus software is used to construct finite element models. After calibration of modeling using an experimental test result as a control model, a parametric study is conducted. The columns with the same geometry, loading, and boundary conditions are analyzed in the parametric study. It is resulted that the hollow GFRP concrete columns provide a greater confinement effect than the solid steel RC columns. The average variation in the ultimate axial load-carrying capacities of the experimental results, from that of the FEA values, is noted to be only 3.87%, while the average difference in the corresponding deformations is 7.08%. Moreover, the hollow GFRP concrete columns possess greater axial load and deformation capacities compared with the solid steel RC columns.

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  • 11.
    Ahmed, Ali Mohamed
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Rashid, Obaidullah
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Optimering av flervåningsbyggnadsstruktur genom att ersätta bärande väggar med pelare och balkar2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I takt med att den globala befolkningen fortsätter att växa, ökar efterfrågan på nya bostadsbyggnader avsevärt. Samtidigt har behovet av bostäder och byggande vuxit över hela världenunder de senaste decennierna, vilket har lett till en ökad efterfrågan på byggmaterial. Betong ärdet viktigaste byggmaterialet för flervåningsbyggnader pga. sin hållfasthet, men det bidrarbetydligt till utsläppen av växthusgaser. För att minska koldioxidavtrycket och främja hållbarhet är det avgörande att minimera materialanvändning med moderna byggmetoder.Syftet med denna studie är att optimera flervåningsbyggnadsstrukturer genom att ersättabärande väggar med pelare och balkar. Studien använder en referensbyggnad belägen iSandvikens kommun och verktyget StruSoft FEM-Design. Studien genomförs i två steg.I steg 1 utförs modellering, design och analys av referensbyggnaden med bärande väggar(byggnad 1). I steg 2 genomförs en förändring av byggnadsstrukturen genom att ersätta debärande väggarna med pelare och balkar av armerad betong (byggnad 2). Samma procedurersom i steg 1 upprepas för den omkonstruerade strukturen. Resultaten jämförs medreferensbyggnaden med hänsyn till utnyttjandegrad, deformation, spänningar, reaktioner, viktoch stabilitet.Ersättningen av bärande väggar med bärande pelare och balkar av armerad betong har variteffektiv. Båda strukturerna uppfyller de nödvändiga kraven. Baserat på resultaten ärdeformationen 9 mm för byggnad 1 och 7 mm för byggnad 2, vilket indikerar att skillnaden ideformation mellan de två strukturerna inte är signifikant.Byggnad 1 har en maximal utnyttjandegrad på 87%, medan byggnad 2 har en högre maximalutnyttjandegrad på 99%. Detta innebär att byggnad 2 kan utnyttjas i större utsträckning änbyggnad 1. Reaktionskrafterna är 563,6 respektive 476,4 kN i båda byggnaderna, vilketindikerar att reaktionskrafterna i byggnad 2 är 15% lägre än i byggnad 1. Båda strukturerna ärstabila, men det finns en skillnad i byggnadernas totala vikt. Vikterna på byggnaderna är 4169respektive 3 143 ton. Resultatet indikerar att byggnadens totala vikt minskar med ca 25% vidanvändning av betongpelare och betongbalkar.

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  • 12.
    Ahmed Waqas, Hafiz
    et al.
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Sahil, Mehran
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Poshad Khan, Adil
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Ejaz, Ali
    National University of Science and Technology, Risalpur 23200, Pakistan.
    Shafique, Taimoor
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Tariq, Zain
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Ahmad, Sajeel
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Onuralp Özkılıç, Yasin
    Necmettin Erbakan University, Konya, Turkey.
    Performance Prediction of Hybrid Bamboo-Reinforced Concrete Beams Using Gene Expression Programming for Sustainable Construction2023In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 16, no 20, article id 6788Article in journal (Refereed)
    Abstract [en]

    The building and construction industry’s demand for steel reinforcement bars has increased with the rapid growth and development in the world. However, steel production contributes to harmful waste and emissions that cause environmental pollution and climate change-related problems. In light of sustainable construction practices, bamboo, a readily accessible and ecofriendly building material, is suggested as a viable replacement for steel rebars. Its cost-effectiveness, environmental sustainability, and considerable tensile strength make it a promising option. In this research, hybrid beams underwent analysis through the use of thoroughly validated finite element models (FEMs), wherein the replacement of steel rebars with bamboo was explored as an alternative reinforcement material. The standard-size beams were subjected to three-point loading using FEMs to study parameters such as the load–deflection response, energy absorption, maximum capacity, and failure patterns. Then, gene expression programming was integrated to aid in developing a more straightforward equation for predicting the flexural strength of bamboo-reinforced concrete beams. The results of this study support the conclusion that the replacement of a portion of flexural steel with bamboo in reinforced concrete beams does not have a detrimental impact on the overall load-bearing capacity and energy absorption of the structure. Furthermore, it may offer a cost-effective and feasible alternative. 

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  • 13.
    Aksoylu, Ceyhun
    et al.
    Konya Technical University, Konya 42250, Turkey.
    Özkılıç, Yasin Onuralp
    Necmettin Erbakan University, Konya, Turkey.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Yıldızel, Sadık Alper
    Karamanoglu Mehmetbey University, Karaman, Turkey.
    Hakeem, Ibrahim Y.
    Najran University, Najran, Saudi Arabia.
    Özdöner, Nebi
    Necmettin Erbakan University, Konya 42000, Turkey.
    Başaran, Boğaçhan
    Amasya University, Amasya 05100, Turkey.
    Karalar, Memduh
    Zonguldak Bulent Ecevit University, Zonguldak, Turkey.
    Application of waste ceramic powder as a cement replacement in reinforced concrete beams toward sustainable usage in construction2023In: Case Studies in Construction Materials, E-ISSN 2214-5095, Vol. 19, article id e02444Article in journal (Refereed)
    Abstract [en]

    The main purpose of this study was to investigate the flexural behavior of reinforced concrete beams (RCBs) containing waste ceramic powder (CP) as partial replacement of cement. For this purpose, flexural tests were carried out using various amounts of mixing ratios. By determining the amount of CP utilized in the optimum ratios, it was aimed both to make predictions for design engineers and to show its beneficial effect on the environment by recycling the waste material. For this purpose, twelve specimens were produced and verified to monitor the flexural behavior. The longitudinal reinforcements percentage (0.77%, 1.21%, and 1.74%) and CP percentage (0%, 10%, 20%, and 30%) were chosen as the parameters. CP could be effectively used up to 10% of cement as a replacement material. Increasing the CP percentage by more than 10% could considerably reduce the load-carrying capacity, ductility, and stiffness of RCBs, specifically when the longitudinal reinforcements percentage was high. In other words, as CP increased from 0% to 30%, the load-carrying capacity decreased between 0.4% and 27.5% compared with RCBs with the longitudinal tension reinforcements of 2ϕ8 without CP. However, reductions of 5.5–39.8% and 2.15–39.5% in the load-carrying capacity occurred respectively compared with RCBs with the longitudinal tension reinforcements of 2ϕ10 and 2ϕ12 without CP. The achieved longitudinal reinforcements percentage was close to the balanced ratio, while more than 10% CP cannot be used without any precautions for mixtures.

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  • 14.
    Alaneme, George U
    et al.
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria; Department of Civil Engineering, Kampala International University, Kampala, Uganda.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Ibe Iro, Uzoma
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria.
    Ganasen, Nakkeeran
    Department of Civil Engineering, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, 603203, India.
    Otu, Obeten N
    Department of Civil Engineering, University of Cross River State, Calabar, Nigeria.
    Udeala, Richard C
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria.
    Ifebude, Blessing O
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria.
    Onwusereaka, Emmanuel A
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria.
    Numerical Analysis and Parametric Study on Multiple Degrees-of-Freedom Frames2023In: Civil Engineering Journal, ISSN 2676-6957, Vol. 9, no 7, p. 1709-1736Article in journal (Refereed)
    Abstract [en]

    The design of multiple degrees-of-freedom frames is critical in civil engineering, as these structures are commonly used in various applications such as buildings, bridges, and industrial structures. In this study, a six-degrees-of-freedom beam-column element stiffness matrix was formulated by superposition of beam and truss elements stiffness matrices and was adapted to statically analyze indeterminate frame structures. The development of a numerical model for the frame structures was achieved using the finite element method in the current study. Also, the investigation of the effects of various parameters such as frame geometries, material properties, and loading conditions was conducted on the internal forces developed in the frame structures. Three different parametric study cases that presented the frame structures with varying geometries and loading conditions were analyzed utilizing this matrix approach for the sake of emphasis and to evaluate the flexibility and adequacy of this formula to analyze the indeterminate frames using the MATLAB software. The analysis method comprised the derivation of the system displacements employing the relationships between the stiffness matrix and fixed end forces as the force vector and taking the attained displacements, which would be transformed to the local coordinates to obtain the member forces. The computed results from the element stiffness matrix approach were further statistically compared with the results achieved from the finite element software (SAP2000) applying the analysis of variance (ANOVA). The statistical results showed a P-value > 0.05, which indicated a good correlation between the compared results and adequate performance for the derived beam-column element matrix formula method. 

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  • 15.
    Al-Asadi, Bashar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Energikartläggning av Montessoriskolan2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy use is rising continuously every year. This is due to economic growth andincreased population. The construction sector consumed 40% of total energy use inSweden. Reducing energy needs in the construction sector is important for Swedento achieve energy goals for reduced energy use in the future. Therefore, energy efficiency measures in buildings today are one of the main goals of energy policytowards 2020 targets.To identify current energy use for a building, an energy mapping is first step. Theenergy survey is carried out at Gefle Montessori School in Gavle. The buildingconsists of ground floor and basement floor. The school building was built in thesixties, which makes their energy use interesting. The school building's energymapping based on energy calculations, collection data and energy simulations.There are various energy efficiency measures that can be implemented if energyefficiency measures are profitable.I have this work descriptions various measures for energy efficiency in Gefle Montessori School. With the help of software IDA ICE, the basic model was created forthe school building and collection data is put into IDA ICE which was simulatedfor one year. The total electricity use of the school building was approximately 85 032 kWh/year, while the district heating was 325 227kWh /year. The result showed a largereduction in energy use, which can be carried out various energy efficiencymeasures in the school building such a change of windows, replacement of lightingand additions insulation on exterior walls. According to results, heat losses via windows were large 88 634 kWh /year and improvements on the windows can be a wayto reduce energy losses. By making a calculation after improvements, reduce heatlosses to 61 991 kWh /year. To add more insulation to the outer wall to reduce heat loss. With additional insulation, energy consumption is reduced to 395 699 kWh /year.LED installation for every space in the building is a way to reduce energy use andLED lighting provide good efficiency than current lighting. Switching to LEDs reduces energy consumption to 405 983 kWh /year.viiiThe results of the study showed that the school building can reduce their energyuse by 10 % using all measures. Economic aspects have been taken into accountthat show the same between energy saving and economic profit.

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  • 16.
    Alasadi, Rasha
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Matsson, Sofie
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Kvartersnära insamling av hushållsavfall: - Ett förslag till bostadsbolaget Ljusdalshem2020Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Every year household waste is incorrectly sorted, which contributes to a lot of material goes to incineration instead of recycling. By expanding the sorting of household waste, the cycle can be linked, and the material can be used as a new resource. Despite the directive and the existing laws, the amount of waste continues to increase. A new regulation has been prepared to remedy this and will enter into force in 2025, where all residential properties will have neighborhood close sorting. 

    The purpose of the study is to help the housing company Ljusdalshem develop a proposal for neighborhood-wide collection in the area Gärdeåsen, which is located in Ljusdal municipality. The Gärdeåsen area is built under the million programs. The area has only two fractions with the collection of combustible and cardboard. In order to carry out this work, a qualitative method has been used with the help of a literature study and semi-structured interviews. Two previous projects have been studied to include important aspects of the proposal. The projects that have been studied are Nordost and Andersberg, which have implemented neighborhood-wide collection of the housing company Gavlegårdarna in Gävle. The projects differ in design and were therefore of interest to study in order to gather important aspects to consider when forming the proposal for neighborhood-wide collection for the housing company Ljusdalshem.

     

    The result presents a proposal to Ljusdalshem for implementation of neighborhood-wide collection in the Gärdeåsen area. What the authors came up with was to build four new recycling rooms, with collection for newspapers, packaging, waste and food waste. New recycling rooms have been proposed because the existing buildings are worn, and renovation would be extensive. There are important aspects to consider when building neighborhood-wide collection. An important aspect to prevent odors is to remove food and residual waste from the recycling room, therefore the four recycling rooms should be supplemented with underground containers for food and residual waste. In order to obtain an effective result of the sorting of household waste, behavioral changes are of great importance in the proposal, as there is a lack of knowledge in areas with a mixed cultural background. Ljusdalshem should work with informative measures. This means that knowledge is promoted, and the sorting of household waste can increase. The physical design is also important for increasing the sorting. Lighting, large windows and light walls are measures that promote the feeling of security in the recycling room.

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    Kvartersnära
  • 17.
    Albeman, William
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Lif, Emma
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Hur kan en gammal industribyggnad med kulturhistoriskt värde göras om till bostäder?: En fallstudie av lokstallarna i Bollnäs2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In Sweden there is a shortage of housing whilst old, abandoned industrial buildingstake up space on desirable land. These buildings generally do not live up to today’s standards regarding comfort and energy efficiency and are therefore not used today. If these buildings were to be renovated into housing, they could help remedy the housing shortage. However, many of these buildings are protected from distortion by law which makes renovation and remodeling difficult. The purpose of this work has been to provide solutions for how an old industrialbuilding with cultural-historical values can be remodeled into housing. The solutions consist of floor plans and drawings modeled in Autodesk Revit. The possibilities and difficulties with this kind of project as well as solutions to expected problems are also presented in the report. This work was executed as a case study on one of the old locomotive depots in Bollnäs. Since the building for this project is an old locomotive depot, it is positioned close to the railroad. Noise and ground pollution are therefore important to consider and demand certain measures, for example retaining walls, noise barriers and excavation of polluted soil. An energy simulation of the building was made using BV2 to determine the energy usage of the building. The walls, roof and slab were additionally insulated for the purpose of meeting the demands of energy efficiency and comfort defined by BBR 29. The insulation had to be internally constructed in order to avoid distortion of the facade. Additionally, all windows and doors had to be made energy efficient while remaining aesthetically preserved. Internal insulation is generally problematic due to problems with moisture. The solution to this problem was to insulate the walls with polyurethane foam and the slab with cellular plastic. In order to make the building energy efficient, the building should be heated using district heating in combination with photovoltaic panels. This building is well suited for solar panels due to the large, black metal sheet roof and shadow free placement. The study shows the complexity of refurbishing this type of building. The renovation is extensive, and the floor plans are characterized by compromises. It is possible to renovate the building without distorting it. A better alternative would be to use the building for other functions such as a store, restaurant or bar. 

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  • 18.
    Albuquerque, Daniel P.
    et al.
    Universidade de Lisboa.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Linden, P. F.
    University of Cambridge.
    Carrilho da Graça, Guilherme
    Universidade de Lisboa.
    Experimental and numerical investigation of pumping ventilation on the leeward side of a cubic building2020In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 179, article id 106897Article in journal (Refereed)
    Abstract [en]

    Unstable interaction between shear layers that form in the wake of an isolated building exposed to wind can drive natural pumping ventilation in windward and leeward facing rooms with two or more horizontally separated openings. This paper presents an experimental and numerical study of pumping ventilation in a three-story cubic building with two leeward openings in its middle floor. Reduced-scaled measurements were performed in the University of Gävle atmospheric-boundary-layer wind tunnel. The ventilation mechanism was investigated using smoke visualization, hot wire anemometry and particle image velocimetry. Effective ventilation rates were obtained using a tracer gas decay method. Experimental results confirmed that pumping ventilation is a 3D oscillatory unstable phenomenon with periodic behavior over several oscillation cycles. Measured flowrates show a linear relation between the effective ventilation rate and window separation. The numerical simulations used two turbulence modeling approaches: unsteady Reynolds-averaged Navier-Stokes (URANS) and large eddy simulation (LES). Both URANS and LES could predict vortex shedding frequency with an error below 5%. LES showed a good agreement with the measured ventilation rates, with an error below 10%, while URANS underestimated ventilation rates by at least 40%. The ventilation efficiency, obtained by LES, ranged between 0.60 and 0.75 (for the case with larger window separation). The results show that LES may be a suitable simulation approach for pumping ventilation. In contrast, URANS cannot simulate pumping ventilation.

  • 19.
    Albuquerque, Daniel
    et al.
    Universidade de Lisboa, Portugal.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Linden, Paul
    University of Cambridge, UK.
    da Graca, Guilherme Carrilho
    Universidade de Lisboa, Portugal.
    LES simulation of oscillating natural ventilation driven by vortex shedding in isolated buildings2020In: Proceedings of Building Simulation 2019: 16th Conference of IBPSA / [ed] Corrado et al., IBPSA , 2020, p. 644-649, article id 11456Conference paper (Refereed)
    Abstract [en]

    A recently published study presented a new type of natural ventilation (NV) flow, named pumping ventilation. The oscilatory mechanism of vortex shedding that occurs at the wake region of an isolated building drives this new type of ventilation in rooms with two (or more) openings facing the leeward or windward side of an isolated building. This paper presents a validated Large Eddy Simulation (LES) study of oscillating/pumping NV in an isolated building using three different separations (s') between its two windows. LES is validated using an experimental database from measurements performed at the University of Gavle boundary layer wind tunnel (WT). The measurements use a cubic model with 0.45m side representing a three-story building at a 1/20 scale that allows the use of bottom-hung windows. LES results show a good agreement with the measured non-dimensional ventilation rates. A dimensionless analysis shows the dominant frequencies of the pumping flow, are close to the Strouhal frequency.

  • 20.
    Alcoverro Colom, Pau
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    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 credits / 15 HE creditsStudent thesis
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    A new energy model for the Lakshadweep islands
  • 21.
    Alhajjaj, Eman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Sanchez, Marvin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Effektivisering av byggprocessen med hjälp av lean: En fallstudie på ett företag med prefabricerat byggande2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The increasing housing shortage occurring in society has for a long time created a great need to build housing quickly and cost-effectively. This has led to more and more industrialization of its building process, where housing is manufactured in modular form in the factory. With industrial processes, companies can give freedom to workers to take responsibility for the process in which they participate, and thus contribute with improvements and standardization in the process. One concept that is very suitable for this is The Toyota Production system (TPS), also called Lean production. Today, there are studies where Lean has been combined with the building process. The purpose of this study is to investigate and study whether the building process for prefabricated houses can be streamlined using the Lean method and, if so, how. As an efficiency improvement is sought in this study, questions about the basic principles of Lean will be involved.

    A qualitative data collection is done, which is based on an interview study. The questions for these interviews have been formulated with the help of literature contained within the subject. The interview questions are structured by being open where the respondent is given the opportunity to speak freely and in detail about the topic.

    Two companies were selected for this study. One company is a Stockholm stationed company that deals with prefabricated construction. These do not use the Lean working method as standard in their work. The other company is a company that also deals with prefabricated construction on a larger scale and that they use the Lean working method throughout their organization.

    The theory behind the study is the actual implementation of Lean in an existing building process that does not use the working method. By introducing Lean's basic principles into a company that does not use it today, this study will describe what elements can be applied from Lean's perspective.

    Finally, improvement measures, based on Lean's principles, are being introduced to improve and streamline the construction process of prefabricated construction at the particular company where the study was conducted.

    The aim of the study is to describe and analyze the construction process for industrial companies, the obstacles that arise in the process and how can Lean streamline the construction process from the 14 principles.

    Key-word: Efficiency, Lean, Prefabricated, Modular house, Construction, Construction process, Elimination, The Toyota Way, Lean principle

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    Effektivisering av byggprocessen med hjälp av Lean
  • 22.
    Ali, Ali Talib
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Resilient cooling technologies: Simulation study to determine the cooling capacity in old residentialbuildings located in mid-Sweden2022Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Long-term changes in the climate conditions have increased the need foradequate thermal comfort systems. These alternations influence extremeevents, which their intensity and frequency have increased over the past years.Moreover, this study focuses on space cooling and parameters that the systemshould have to be considered as resilient. Literature study was done to presentthe concept of resilience as well as the different methods used to provide spacecooling. In addition, the cooling systems suggested in this study, which aredistrict cooling and absorption cooling, were presented and explained.Furthermore, the study focuses on cooling demand in a group of residentialbuildings based on different thermal characteristics, which were implementedbased on building regulations from late 1960s to early 1980s. The buildingthermal properties were used as input to obtain their cooling demand by usingbuilding energy simulation tool. Based on the acquired results, an evaluationhas been made for the cooling demand of those buildings. Further analysispresented a correlation between the cooling demand and thermal properties ofthe buildings and aided in the determination of the required cooling capacity.The selection of the capacities was based on the resilience criterion as the systemhas to be able to provide adequate performance and safety for the occupantsduring extreme events. Furthermore, an assessment was done to compare thesuggested system based on their capacities and the primary energy use.

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    Fulltext99
  • 23.
    Ali, Remen
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Issa, Yaser
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Återanvändning av byggnadsmaterial: En fallstudie om Andersberg förskola i Gävle2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This work is about recycling of building materials. The aim of this work is to find out which building materials and equipment could be reused after the deconstruction of the Andersbergsgården preschool in Gävle, and to examine the profitability of these building materials and equipment if it is to be selectively demolished, stored and then reused.Both theory and conclusion were formulated through a literature study at the beginning of the work and contact with the involved companies. Research shows that 95% of building materials can be recycled. This percentage can be achieved if the building does not contain hazardous substances in the construction or it´s in bad condition.The study highlights some of the barriers to the wider use of reused materials. Examples of this are the verification of guarantees and qualities of the materials. It has been shown that the cost of traditional demolition generally is higher than the cost of selective demolition. What can be stored and reused are doors because these are in good condition.In the end, the conclusion is that all building materials in the Andersbergsgården preschool, with the exception of concrete and insulation, can be recycled. The reasons for this are that the concrete has had moisture problems and the insulation is too old to be recycled

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  • 24.
    Ali, Sabir
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    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 credits / 30 HE creditsStudent thesis
    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.

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  • 25.
    Ali, Shara
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Khatibi, Farida
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Påbyggnad av våningsplan ovanför befintligt höghus: En fallstudie inom förtätning av storstäder2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Throughout Sweden, the cities expand due to increased population. The expansion causes housing shortage and the need for larger infrastructure especially in larger cities where the ground surface is more limited and restricted. These circumstances cause a dilemma as to whether the establishment of new infrastructure or new residential apartments should be prioritized, basically the establishment of new infrastructure vs. the establishment of new residential apartments.  

    A suggestion of a solution for this case is vertical building extension implying to build above an existing building without any utilization of the ground surface being required or needed. The empty space above an existing building, whether it is a high rise building or a single-family house, is being turned to advantage for expansion of the floor area. 

    This concept is an alternative to horizontal building extension. Unlike vertical building extension, it requires utilization of the ground surface and is therefore not suitable for this case.

    This thesis constitutes a case study covering the projecting phase in the building process of vertical building extension of storeys on existing high-rise buildings located in large cities such as Stockholm. Vertical building extension is presented as a solution for densification of large cities. There are several subjects which are investigated in the projecting phase. Architecture, urban planning, geotechnics, building construction and sustainability are a few of the subjects and these are specifically investigated in this case study. 

    The aim with this paper is through the mentioned investigation, to clarify why vertical building extension could be a solution for urban circumstances like housing shortage.

    This case study is based on qualitative research. Collection of scientific information has been done through both literature research and online research. 

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  • 26.
    Aljaberi, Saif
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Majeed, Aram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Energisimulering i modulhus: Fallstudie för uppskattning av energiprestanda och därefter energieffektivisera enligt passivhusstandaren2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    The Building sector is today an important sector in our society, which means that more people move from the urban area to the big cities, which in turn increases building production. The building and service sector is the largest energy waste in Sweden and internationally, which is about 40% of Sweden's total energy use and 60% of that energy goes to heating. The EU Directive Energy Performance of Buildings Directive (EPBD), implemented the concept of near zero-energy houses, which comes into full force in 2020, which means that all newly-built buildings must be energy-efficient with better energy performance than todays buildings. This is in connection with the need of houses/buildings and rental costs continuing to increase. For this reason, Ljusbo Hyreshus AB has invented a solution that includes both climatesmart rental apartments and cheap rental costs, which has attracted more than 20 communes (kommuner in Sweden) to offer land for these apartments. The purpose of this thesis is to find out the energy performance of one of Ljusbo Hyreshus AB's prototype module houses. Furthermore, improvement proposals would be developed to make the module house more energy efficient. The prototype house consisted of a single-storey modularhouse that stay in Söderhamn, which has been chosen in this thesis for further investigations. The house had a total area of 45 m2 and consisted of 3 rooms and kitchen. In this case study, the energy performance has been developed using analysis methods in the form of hand calculations and the energy signature method. Subsequently, the result of the analysis would be validated and would form the basis for later identification of various energy efficiency measures that contributed to the reduction of energy performance in the house and thereby achieved the passive house standard. The result shows that the modularhouse does not fullfil BBR's requirements at present, because the house misses important components which is important for energy performance. For this reason, improvement proposals, specifically regarding the climate shell, on energy efficiency measures have been developed in this report. With the help of these energy efficiency measures, which mainly consist of additional insulation and energy-efficient windows and with an energy-efficient ventilation system with heat recovery (FTX) and an installed air-water heat pump, the passive house standard has been possible to achieve. Future measures, such as the installation of solar cells, have also been examined in the report. This is due to converting the building from a passive house to a plus energy house.

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    Energisimulering i modulhus
  • 27.
    Al-sabti, Merna
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Lönsamhet och affärsmodell för en biogasanläggning som drivs av lantbrukare2019Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Biogas production has environmental and social advantages for farmers, the target group of this study, but there are obstacles. Profitability issues can be resolved by, for example, applying business models. The purpose of the study was to investigate which business model can be applied by an agricultural biogas plant and to analyze the profitability of the company through assessment of key figures and DuPont models. An agricultural biogas plant was selected and various studies on the profitability and business models of agricultural biogas plants were used as a basis for comparing the example plant with previous research. Interviews were conducted with a partner in the biogas company. In order to determine the profitability of the company, calculations of key figures and DuPont models were carried out for the years 2017 and 2018. The study identified various success factors for the company, regarding collaboration, entrepreneurial characteristics, long-term perspective and the relationship to the market. The results show that even if the company has lacked a structured business model, their work is following recommendations given by published business models. The analysis shows that the company has good profitability, but profitability is difficult to evaluate on the long term, since data for several years were not available in the yearly report of the company. The conclusions from the present study are that the company is profitable, however, profitability risks are present, which demonstrate that the company cannot lower its prices due to competition, and they require knowledge about costs to maintain or increase profit over time. The present study proposes that the company utilizes a formal business model, which needs to include financial analysis for long-term and maintained profitability. The business model of the company could be used as a source of inspiration to other farmers, as long as it will be expanded to include financial analysis.

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    fulltext
  • 28.
    Al-Sabti, Rita
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Fransson, Josefin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Missfärgat dricksvatten i Sandvikens kommun: En studie med avseende på järn och mangan2021Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Drinking water is a cornerstone to a prosperous society. The quality of drinking water is affected by the type of raw-water sources and how drinking water treatment is carried out in a drinking water treatment plant. If the quality of the drinking water deteriorates, it may indicate that the drinking water treatment is not optimal or that the quality of raw-water sources has changed.The municipality of Sandviken in Sweden has had recurring problems with brown and black discolorations of the drinking water. Brown and black discolorations can be caused by oxidation of iron and manganese in the drinking water distribution system. The oxidation of manganese leads to the formation of manganese dioxide that can accelerate the corrosion processes of cast iron pipes. The Swedish Food Agency has set a limit value for the concentration of iron and manganese in drinking water to prevent the formation of precipitates in the drinking water distribution system. The aim of the study is to investigate whether the discolorations are due to high levels of iron and manganese in the drinking water. Water samples were collected to practically and statistically analyse the concentrations of iron, manganese and the formation of manganese dioxide. The statistical analysis showed that the levels of manganese were at their highest closest to the drinking water treatment plant. No other statistical correlations have been established. The analysis of manganese showed that 20 out of 31 water samples were above the limit value. The limit value for manganese was already exceeded at the drinking water treatment plant. The analysis of iron showed that 2 out of 24 water samples were above the limit value. Results also showed the presence of manganese-oxidizing microorganisms in the drinking water distribution system. Manganese is emitted from the drinking water plant and favors microorganisms as well as increases the formation of manganese dioxide, which may cause corrosion on cast iron pipes. Thus, the composition of the drinking water can affect or accelerate corrosion in the drinking water distribution system.Theoretically, the discolorations that have been experienced by the users may be due to a high concentration of manganese. However, it cannot be excluded that discolorations may be caused by other factors as the result did not provide a statistical relationship between discoloration and the concentration of iron and manganese. Further studies are required to determine all the causes behind discoloured drinking water. The problem of the concentrations of manganese should be solved, whether or not it is the main cause of the water discoloration. The concentrations of iron and manganese are likely to increase in the raw water due to climate change. If the drinking water plant continues to mix surface and groundwater, the problem can be solved by installing a static mixer and introducing a separation step for iron and manganese. When choosing a biological separation method, microorganisms from the drinking water distribution system can be used.

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    Missfärgat dricksvatten i Sandvikens kommun
  • 29.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    El Tayara, Khaled
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Energy Performance Evaluation of Historical Building2022In: Buildings, E-ISSN 2075-5309, Vol. 12, no 10, article id 1667Article in journal (Refereed)
    Abstract [en]

    Retrofitting measures in old buildings aimed at reducing energy usage have become important procedures meant to counteract the effects of climate change and greenhouse gas emissions. The aim of this study is to evaluate energy usage, thermal comfort, and CO2 emissions of an old building by changing parameters such as building orientation, shading systems, location, low energy film application, and alternative energy supply in the form of a geothermal heat pump. When evaluating the buildings in terms of geographical location with or without applying the low energy film, the results show that the city of Gävle in Sweden requires the most heating energy, 150.3 kWh/m2∙year (B0) compared to Jakarta (L0), which requires 23.8 kWh/m2∙year. When examining the thermal comfort, cases B4 and L4 demonstrate the best results in their respective categories (B0–B4 are cases without low energy film and L0–L4 are cases with applied low energy film). The results for the CO2 emissions levels for B0–B4 and L0–L4 indicate that B4 has the highest value, 400 kg CO2 eq/year higher than B0, and L1 has the lowest value, 731 kg CO2 eq/year lower than B0. The economic feasibility study illustrates that the installation of a geothermal heat pump with at least a coefficient of performance of 4.0 leads to a shorter payback period than solely applying LEF.

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  • 30.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Elousa Ansa, Ibai
    Assessment of Thermal Comfort and Indoor Air Quality in Library Group Study Rooms2023In: Buildings, E-ISSN 2075-5309, Vol. 13, no 5, article id 1145Article in journal (Refereed)
    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.

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  • 31.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Reducing energy usage in multi-family housing2019In: 2019 9th International Conference on Future Environment and Energy 9–11 January 2019, Osaka, Japan, Institute of Physics Publishing (IOPP), 2019, Vol. 257, article id 012030Conference paper (Refereed)
    Abstract [en]

    The energy usage in residential sector have been around 22% of the total energy use in the world and increasing due to the population growth and higher living standards. The energy sources for this are made up primarily of non-renewable energy resources which generates a large amount of global greenhouse gases. A lot of countries have implemented various regulations and rules to reduce the energy usage in buildings and promoting the use of renewable energy technologies. This paper presents a parametric study of a typical multi-family building in its pre-design stage. The climate location used is Sweden (Gothenburg) and Japan (Osaka). The aim of the study is to compare various configurations and to examine how they affect the energy use. The most interesting configurations are the use of heat pump and solar cells. Other configurations that are examined are infiltration levels, pressure coefficients, wind impact, ventilation with heat recovery, ventilation scheduling, building orientation and finally changing U-values in the building material. Results of this study show that the energy saving, by utilizing a heat pump and solar panels, can reduce the total energy use by 34.9% for Gothenburg and 32% for Osaka. The results also show that the difference in total energy use between the two cities reduce substantially (3% difference) when utilizing a heat pump in combination with solar panels.

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  • 32.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Karimipanah, Taghi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Numerical investigation of indoor thermal comfort and air quality for an office equipped with corner impinging jet ventilation2023In: Advances in Building Energy Research, ISSN 1751-2549, E-ISSN 1756-2201, Vol. 17, no 5, p. 578-604Article in journal (Refereed)
    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.

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  • 33.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Larsson, Ulf
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Karimipanah, Taghi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Experimental Investigation of Ventilation Performance of Different Air Distribution Systems in an Office Environment: Heating Mode2019In: Energies, E-ISSN 1996-1073, Vol. 12, no 10, article id 1835Article in journal (Refereed)
    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.

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  • 34.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Larsson, Ulf
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Karimipanah, Taghi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Experimental investigation of ventilation performance of different air distribution systems in an office environment – cooling mode2019In: Energies, E-ISSN 1996-1073, Vol. 12, no 7, article id 1354Article in journal (Refereed)
    Abstract [en]

    The performance of a newly designed corner impinging jet air distribution method with an equilateral triangle cross section was evaluated experimentally and compared to that of two more traditional methods (mixing and displacement ventilation). At nine evenly chosen positions with four standard vertical points, air velocity, turbulence intensity, temperature, and tracer gas decay measurements were conducted for all systems. The results show that the new method behaves as a displacement ventilation system, with high air change effectiveness and stratified flow pattern and temperature field. Both local air change effectiveness and air exchange effectiveness of the corner impinging jet showed high quality and promising results, which is a good indicator of ventilation effectiveness. The results also indicate that there is a possibility to slightly lower the airflow rates for the new air distribution system, while still meeting the requirements for thermal comfort and indoor air quality, thereby reducing fan energy usage. The draught rate was also lower for corner impinging jet compared to the other tested air distribution methods. The findings of this research show that the corner impinging jet method can be used for office ventilation.

  • 35.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Larsson, Ulf
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Yamasawa, Haruna
    Kyushu University, Fukuoka, Japan.
    Kobayashi, Tomohiro
    Osaka University, Osaka, Japan.
    Numerical investigation of the flow behavior of an isothermal corner impinging jet for building ventilation2022In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 223, article id 109486Article in journal (Refereed)
    Abstract [en]

    The corner impinging jet concept has been proposed as a new air distribution system for use in office environments. The present paper reports the mean flow field behavior of an isothermal corner-based turbulent impinging jet in a room. A detailed experimental study is carried out to validate the numerical simulations, and the predictions are performed using three turbulence models. RNG k−ε model was chosen for this study. This study investigates the influence different configuration parameters such as jet discharge height, diffuser geometry (shape and size) and supply airflow rate have on the flow field. The results show that the diffuser geometries used in this study had in general a minor effect on the velocity developments along the centerline of the floor, maximum velocity decay and jet spreading rate except for some specific cases. When evaluating the triangle geometry cases, the results show that all the cases with volume flow <20 L/s are able to meet Boverket's building regulations velocity requirement both for summer and winter. The applicability evaluation show that the results can be considered for room sizes between ≈25 and 100 m2. In addition, the wall confinement effect (90° vs. 180°) is having a significant impact on the maximum velocity decay for corner impinging jet ventilation. In the regression analysis the results shows that the distance along the diagonal centerline of the room has the most impact on the evaluation of maximum velocity decay and jet spreading rate.

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  • 36.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Yamasawa, Haruna
    Osaka University, Japan..
    Kobayashi, Tomohiro
    Osaka University, Japan..
    Karimipanah, Taghi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Energy saving, indoor thermal comfort and indoor air quality evaluation of an office environment using corner impinging jet ventilation2023In: Developments in the Built Environment, ISSN 2666-1659, Vol. 15, article id 100179Article in journal (Refereed)
    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.

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  • 37.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Choonya, Gasper
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Experimental Evaluation of the Ventilation Effectiveness of Corner Stratum Ventilation in an Office Environment2019In: Buildings, E-ISSN 2075-5309, Vol. 9, no 7, article id 169Article in journal (Refereed)
    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.

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  • 38.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Mattsson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    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 Climate2023In: Buildings, E-ISSN 2075-5309, Vol. 13, no 1, article id 156Article in journal (Refereed)
    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.

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  • 39.
    Ameen, Arman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Yamasawa, Haruna
    Kyushu University, Fukuoka, Japan..
    Kobayashi, Tomohiro
    Osaka University, Osaka, Japan..
    Numerical Evaluation of the Flow Field of An Isothermal Dual-Corner Impinging Jet for Building Ventilation2022In: Buildings, E-ISSN 2075-5309, Vol. 12, no 10, article id 1767Article in journal (Refereed)
    Abstract [en]

    The corner impinging jet ventilation is a new air distribution system for use in office environments. This study reports the mean flow field behavior of dual isothermal corner-placed inlets based on an impinging jet in a square-shaped room with the size of 7.2 m × 7.2 m. A detailed numerical study is carried out to evaluate the influence the different configuration parameters, such as the inlet placement, same side or opposite side, and supply airflow rate, have on the flow field. The results show that the highest velocity peak for all cases is obtained at x = 0.5 m and the lowest at x = 3.5 m. The velocity profiles development remains similar when increasing the flow rate. For the zone evaluation, the results show that Case 1 and 2 (V = 20 L/s) meet the requirement of not exceeding 0.15 m/s during the heating season in the occupied zone according the BBR standard both for same-side and opposite-side configurations. For Case 4, the optimal placement of the inlets is opposite to each other when V = 30 L/s for the BBR requirements. Case 1, 2, 3, 4, 5, and 7 all meet the requirement of not exceeding 0.25 m/s during the cooling season both for the same-side and opposite-side configurations. For Case 8, the optimal placement of the inlets is opposite to each other when V = 50 L/s.

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  • 40.
    Andersson, Emelie
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Aziz, Shniar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    En jämförelse mellan gröna-, metall- och gråa tak för ett oisolerat parkeringshus utifrån dess olika temperaturer och dagvattenhantering2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Since climate change increases and changes constantly, it contributes to higher average temperatures, ice melting and has a great impact on our ecosystem. This will then lead to a warmer climate, which means increased precipitation and milder winters. One of the reasons to climate change is urbanization, meaning people moving to the cities. To succeed in changing the climate, international cooperation and common goals are required. At the northern part of Brynäs, in the municipality of Gävle, work is currently in progress around the area where the factory of Läkerol was once standing. The area continues to be rebuilt and the outcome will eventually be called Godisfabriken. There, amongst other, a car park will be built for the newly built homes. The aim of this study is to compare metal roofs, grey concrete roofs and green roofs within the two aspects of stormwater management and temperature. Then analyse which alternative of these three roofs would be most advantageous for the car park of Godisfabriken.

     

    The focused roofs are green, metal and concrete. A green roof is when it's completely or partly covered by a layer of vegetation and metal roofs are different sheet roofs with steel and aluminium-zinc. Grey roofs are made of concrete which works as both floor and ceiling. A building's roof affects which air temperature the surroundings has with its slope, vegetation and surrounding buildings. Another problem with urbanization and a warmer climate is stormwater management, which means rain and melted snow from roofs, parking areas and other hard surfaces.

     

    The method includes a literature study and calculations. The literature study gave research on temperature for all roofs as well as stormwater management for green roofs. Calculations were made for stormwater management and temperature with its flow, absorption, reflectance and heat transfer.

     

    The literature study and the calculations showed that green roofs have a high SRI value of 80 while the remaining roof is at around 40. The higher SRI, the lower surface temperatures on the material. This is proven in both methods when green roofs according to the literature study received a maximum surface temperature of 38 °C and 48 °C. According to the literature study green roofs can preserve more than 50 % of the rainwater. They also had a water flow rate of 1.97 l/s, which is less than half of what the metal roof got in the calculations. Since green roofs had both low air and surface temperatures, as well as longer drainage times and most absorbed water, green roofs are a more suitable choice than metal and grey concrete.

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  • 41.
    Andersson, Erik
    et al.
    Stockholm Resilience Centre, Stockholm University; North-West University, Potchefstroom, South Africa.
    Grimm, Nancy B
    Arizona State University, Tempe, AZ, USA.
    Lewis, Joshua A
    Tulane University, New Orleans, LA, USA.
    Redman, Charles L
    Arizona State University, Tempe, AZ, USA.
    Barthel, Stephan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science. Stockholm Resilience Centre, Stockholm University.
    Colding, Johan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science. The Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Stockholm.
    Elmqvist, Thomas
    Urban climate resilience through hybrid infrastructure2022In: Current Opinion in Environmental Sustainability, ISSN 1877-3435, E-ISSN 1877-3443, Vol. 55, article id 101158Article in journal (Refereed)
    Abstract [en]

    Urban infrastructure will require transformative changes to adapt to changing disturbance patterns. We ask what new opportunities hybrid infrastructure—built environments coupled with landscape-scale biophysical structures and processes—offer for building different layers of resilience critical for dealing with increased variation in the frequency, magnitude and different phases of climate-related disturbances. With its more diverse components and different internal logics, hybrid infrastructure opens up alternative and additive ways of building resilience for and through critical infrastructure, by providing a wider range of functions and responses. Second, hybrid infrastructure points toward greater opportunities for ongoing (re)design at the landscape level, where structure and function can be constantly renegotiated and recombined.

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  • 42.
    Andersson, Hanna
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    Ahonen-Jonnarth, Ulla
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    Holmgren, Mattias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Marsh, John E.
    University of Central Lancashire, UK; Luleå University of Technology.
    Wallhagen, Marita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Bökman, Fredrik
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    What influences people’s tradeoff decisions between CO2 emissions and travel time? An experiment with anchors and normative messages2021In: Frontiers in Psychology, E-ISSN 1664-1078, Vol. 12, article id 702398Article in journal (Refereed)
    Abstract [en]

    One of the today’s greatest challenges is to adjust our behavior so that we can avoid a major climate disaster. To do so, we must make sacrifices for the sake of the environment. The study reported here investigates how anchors (extrinsic motivational-free information) and normative messages (extrinsic motivational information) influence people’s tradeoffs between travel time and carbon dioxide (CO2) emissions in the context of car travel and whether any interactions with environmental concern (an intrinsic motivational factor) can be observed. In this study, people received either a CO2, health or no normative message together with either a high anchor, a low anchor, or no anchor. People that received both a high anchor and a CO2 emission normative message were willing to travel for a longer time than those that only received a high anchor. If a low anchor was presented, no differences in willingness to travel for a longer time were found between the three different conditions of normative message groups, i.e., CO2 normative message, health normative message, or no normative message. People with higher concern for the environment were found to be willing to travel for a longer time than those with lower concern for the environment. Further, this effect was strongest when a high anchor was presented. These results suggest that anchors and normative messages are among the many factors that can influence people’s tradeoffs between CO2 emission and travel time, and that various factors may have to be combined to increase their influence over pro-environmental behavior and decisions.

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  • 43.
    Andersson, Hanna
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    Bökman, Fredrik
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    Wallhagen, Marita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Holmgren, Mattias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Sörqvist, Patrik
    University of Gävle, Faculty of Education and Business Studies, Department of Business and Economic Studies.
    Ahonen-Jonnarth, Ulla
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    Anchoring effect in judgments of objective fact and subjective preference2021In: Food Quality and Preference, ISSN 0950-3293, E-ISSN 1873-6343, Vol. 88, article id 104102Article in journal (Refereed)
    Abstract [en]

    The way by which various sources of external information interact in their effects on judgment is rarely investigated. Here, we report two experiments that examine how two sources of external information—an anchor (a reference price) and an eco-label—influence judgments of an objective fact (product price) and a subjective preference (willingness-to-pay for the product). Participants’ price judgments were drawn in the direction of the anchor point, whereas the eco-label resulted in higher judgments of objective fact (Experiment 1) but did not influence subjective preference (Experiment 2). Interestingly, the eco-label seemed to strengthen the effect of the high anchor in judgments of objective fact. Further, participants with higher environmental concern answered a higher price on the subjective preference questions when they received a high anchor, as well as a lower price when they received a low anchor in comparison to the low environmental concern group. This study demonstrates that various external information sources can strengthen each other’s effects on consumer belief about products, while the effects are weaker for consumers’ preferences. The implications of the results for decision making are discussed.

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  • 44.
    Andersson, Hanna
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    Holmgren, Mattias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Sörqvist, Patrik
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Threadgold, Emma
    Beaman, Philip
    Ball, Linden
    Marsh, John E.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    The Negative Footprint Illusion is Exacerbated by the Numerosity of Environment-Friendly Additions: Unveiling the Underpinning Mechanisms2023In: Journal of Cognitive Psychology, ISSN 2044-5911, E-ISSN 2044-592XArticle in journal (Refereed)
  • 45.
    Andersson, Harald
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    An Investigation Concerning Optimal Design of Confluent Jet Ventilation with Variable Air VolumeManuscript (preprint) (Other academic)
  • 46.
    Andersson, Harald
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Numerical and experimental study of confluent jets supply device with variable airflow2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In recent years, application of confluent jets for design of ventilation supply devices has been studied. Similarly, numerus studies have been made on the potential and application of variable air volume (VAV) in order to reduce the energy demand of ventilation systems. This study investigates the combination of supply devices based on confluent jets and VAV, both in terms of the nearfield flow behavior of the device and the impact on thermal comfort, indoor air quality and energy efficiency on a classroom-level space when the airflow rate is varied.

    The method used in this study is an experimental field study where the confluent jets-based supply devices were compared to the previously installed displacement ventilation. The field study evaluated the energy efficiency, thermal comfort and indoor air quality of the two systems. In the case of the confluent jets supply devices, airflow rate was varied in order to see what impact the variation had on the performance of the system for each airflow rate. Furthermore, the confluent jets supply devices were investigated both experimentally and numerically in a well insulated test room to get high resolution data on the particular flow characteristics for this type of supply device when the airflow rate is varied. The results from the field study show nearly uniform distribution of the local mean age of air in the occupied zone, even in the cases of relatively low airflow rates. The airflow rates have no significant effect on the degree of mixing. The thermal comfort in the classroom was increased when the airflow rate was adapted to the heat load compared to the displacement system. The results lead to the conclusion that the combination of supply devices based on confluent jets can reduce energy usage in the school while maintaining indoor air quality and increasing the thermal comfort in the occupied zone.

    The results from the experimental and numerical study show that the flow pattern and velocity in each nozzle is directly dependent on the total airflow rate. However, the flow pattern does not vary between the three different airflow rates. The numerical investigation shows that velocity profiles for each nozzle have the same pattern regardless of the airflow rate, but the magnitude of the velocity profile increases as the airflow increases. Thus, a supply device of this kind could be used for variable air volume and produce confluent jets for different airflow rates.

    The results from both studies show that the airflow rate does not affect the distribution of the airflow on both near-field and room level. The distribution of air is nearly uniform in the case of the near-field results and the room-level measurement shows a completely uniform degree of mixing and air quality in the occupied zone for each airflow rate. This means that there is potential for combining these two schemes for designing air distribution systems with high energy efficiency and high thermal comfort and indoor air quality.

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  • 47.
    Andersson, Harald
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Optimization of confluent jets ventilation with variable airflow2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In recent years, applications of confluent jets for design of ventilation supply devices have been widely studied. Similarly, numerous studies have been made on the potential and application of variable air volume (VAV) in order to reduce the energy demand of ventilation systems. This study investigates the combination of confluent jets ventilation (CJV) and VAV, both in terms of the near-field flow behavior of the device and the impact on thermal comfort, indoor air quality and energy efficiency in conference room and classroom environments when the airflow rate is varied. For the investigation of CJV with VAV in a classroom environment two experimental studies were performed. One was a field study in a school classroom with a constant supply temperature and four cases with varying heat loads and airflow rates. The other took place in a laboratory environment with five cases, all with varying heat loads, supply temperatures and airflow rates. The two experimental studies measured mean age of air, air speeds and temperatures in the occupied zone. Both studies showed that CJV had higher energy efficiency and indoor air quality than conventional mixing ventilation. The main effects of lower supply temperatures were higher velocities in the occupied zone as well as lower temperatures due to higher energy efficiency . CJV produces mixing ventilation conditions at lower airflow rates (<4.2 ACH) and non-uniform conditions at higher airflow rates. The thermal comfort was similar to that of conventional mixing ventilation and had very small temperature gradients compared to displacement ventilation. For the investigation of CJV with VAV in a conference room environment three combined experimental and numerical studies were performed. One focused on the jet velocity profiles from the CJV supply device, the results of which were used as boundary conditions for the two other studies. The second study measured the conditions in the confluent jet development area and the occupied zone experimentally for six cases with different supply temperatures, airflow rates and nozzle matrix configurations. The results were used for validating the numerical model which was used in the last paper. The final paper was a parametric numerical study which used the response surface method to investigate the impact of four design variables: heat load, number of nozzles, airflow rate and supply temperature on energy efficiency, indoor air quality and thermal comfort. The results show that indoor air quality is increased with higher airflow rates. The energy efficiency has a negative correlation to the heat load but a positive correlation to the airflow rate which results in relatively stable heat removal effectiveness of 110% as heat load is increased and the VAV system compensates with higher airflow rates. The results also show that in a VAV system which aims at providing  uniform temperatures in the occupied zone, the thermal comfort is mostly dependent on a combination of the CLO value and the range of the airflow rates. At low CLO values the range of the airflow rate needs to be increased to create a satisfactory thermal climate.

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  • 48.
    Andersson, Harald
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköpings universitet.
    A numerical and experimental investigation of a confluent jets ventilation supply device in a conference room2022In: Energies, E-ISSN 1996-1073, Vol. 15, no 5, article id 1630Article in journal (Refereed)
    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.

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  • 49.
    Andersson, Harald
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköping Universitet.
    An Investigation Concerning Optimal Design of Confluent Jets Ventilation with Variable Air Volume2024In: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044Article in journal (Refereed)
    Abstract [en]

    This  parametric study aims to predict the  performance of confluent jets ventilation (CJV) with variable air  volume (VAV) from four  CJV  design parameters. A  combination of  computational fluid dynamics (CFD), and response surface method (RSM) has  been used to  predict the  energy efficiency, thermal comfort and  IAQ  for  the  four  expected vital  design variables, i.e.,  heat load (XH),  number of  nozzles (XN),  airflow rate  (XQ) and  supply temperature (XTS).  The  RSM was  used to  generate a  quad-ratic  equation for  the  response variables exhaust temperature (TE),  sup-ply  temperature (TP),  PMV, DR, eT and  ACE. The  RSM  shows that  the  TE, TP and PMV were independent of the number of nozzles. The proposed equations were used to  generate setpoints optimized for  thermal com-fort  (PMV) for  summer, spring and  winter cases with different CLO  fac-tors  and  different TS under a  scenario where the  heat load varied between 10-30W/m2.  TE was  used as  setpoint to  regulate the  airflow rate  to  keep the  PMV values close to  zero. The  results show that  by adapting the TS to the CLO factor both thermal comfort and the energy efficiency can  be  improved. Further energy reduction can  be  gained by downregulating the airflow rate to keep the TP at a fixed setpoint when the  heat load is  decreased. This  means that  a  CJV  can  effectively be combined with VAV  to  improve environmental performance with good thermal comfort (-0.5<PMV <0.5,  DR <20%), above average IAQ (ACE = 106%) and  with a  higher heat removal efficiency (eT = 110%) than conventional mixing ventilation

  • 50.
    Andersson, Harald
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Kabanshi, Alan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköpings universitet.
    On the ventilation performance of low momentum confluent jets supply device in a classroom2020In: Energies, E-ISSN 1996-1073, Vol. 13, no 20, article id 5415Article in journal (Refereed)
    Abstract [en]

    The performance of three different confluent jets ventilation (CJV) supply devices was evaluated in a classroom environment concerning thermal comfort, indoor air quality (IAQ) and energy efficiency. The CJV supply devices have the acronyms: high-momentum confluent jets (HMCJ), low-momentum confluent jets (LMCJ) and low-momentum confluent jets modified by varying airflow direction (LMCJ-M). A mixing ventilation (MV) slot jet (SJ) supply device was used as a benchmark. Comparisons were made with identical set-up conditions in five cases with different supply temperatures (TS) (16–18 °C), airflow rates (2.2–6.3 ACH) and heat loads (17–47 W/m2). Performances were evaluated based on DR (draft rating), PMV (predicted mean vote), ACE (air change effectiveness) and heat removal effectiveness (HRE). The results show that CJV had higher HRE and IAQ than MV and LMCJ/LMCJ-M had higher ACE than HMCJ. The main effects of lower Ts were higher velocities, DR (HMCJ particularly) and HRE in the occupied zone as well as lower temperatures and PMV-values. HMCJ and LMCJ produce MV conditions at lower airflow rates (<4.2 ACH) and non-uniform conditions at higher airflow rates. LMCJ-M had 7% higher HRE than the other CJV supply devices and produced non-uniform conditions at lower airflow rates (<3.3 ACH). The non-uniform conditions resulted in LMCJ-M having the highest energy efficiency of all devices.

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