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  • 1.
    Andersen, Martin
    et al.
    Dalarna University, School of Information and Engineering, Energy Technology. Chalmers University of Technology, Gothenburg.
    Bales, Chris
    Dalarna University, School of Information and Engineering, Energy Technology.
    Dalenbäck, Jan-Olof
    Chalmers University of Technology, Gothenburg.
    Heat distribution concepts for small solar district heating systems – Techno-economic study for low line heat densities2022In: Energy Conversion and Management: X, ISSN 2590-1745, Vol. 15, article id 100243Article in journal (Refereed)
    Abstract [en]

    The high operating temperatures in today’s district heating networks combined with the low energy demand of new buildings lead to high relative network heat losses. New networks featuring lower operating temperatures have reduced relative heat losses while enabling an increase in the use of solar heat. The primary aim of this study was to determine if a particular district heating system can be made more effective with respect to heat losses and useful solar energy, by considering different distribution concepts and load densities. A small solar assisted district heating system with a novel hybrid distribution system has been modelled based on a real case study. This model serves as a basis for two other models where the distribution system and heating network operating temperature is changed. A secondary aim of the study was to determine the economic implications of making these changes, by using costs estimates to calculate the contribution of essential system components to total system cost. Results indicate that a novel distribution concept with lower network temperatures and central domestic hot water preparation is most energy efficient in a sparse network with a heat density of 0.2 MWh/m∙a and a performance ratio of 66%, while a conventional district heating system performs worst and has a performance ratio of less than 58% at the same heat density. In an extremely sparse network with heat density of 0.05 MWh/m∙a, the performance ratio is 41% and 30% for these systems, respectively. A simple economic analysis indicates that the novel distribution concept is also best from an economic point of view, reducing the initial investment cost by 1/3 compared to the conventional concept, which is the most costly. However, more detailed calculations are needed to conclude on this.

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  • 2.
    Andersson, Adam
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Berggren, Pontus
    Dalarna University, School of Technology and Business Studies, Construction.
    Utvärdering av träbjälklag i ett äldre flerbostadshus med avseende på stegljud och nedböjning: Mätningar och möjliga åtgärder och åtgärdsförslag2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    New buildings will only maginally contribute to future quantity of residential housing. Therefor new knowledge of past building technics are required, to asses which action propsals are suitable when interventions are considered. Objective. This study aims to evaluate lightweight timber joist floors in a multi-story residential building from 1903, with regard to footfall noise and deflection. Method. Data has been collected with a survey and through measurements of footfall noise and deflection. The purpose of the survey is to evaluate the residentals subjective perception of footfall noise and deflection. Footfall noise has been measured with a tapping machine in accordance with Swedish Standards. The deflection has been measured with Leica NA2 paired with a parallel-plate micrometer, GFS1, for precise leveling assessment. Results. The survey shows that the residents don’t experience any issues with regard to footfall noise and deflection. The measurements show a L’nT,w+CI,50-2500 level of 55 dB and an average deflection of 0.320 mm/kN. Conclusion. Footfall noise- and deflection levels satisfy today’s requirements according to Swedish Standards and therefor the results doesn’t motivate any action proposals or interventions.

  • 3.
    Andersson, Daniel
    et al.
    Dalarna University, School of Information and Engineering.
    Warnerfjord, Alexander
    Dalarna University, School of Information and Engineering.
    Påbyggnad med förstärkningstomme i befintlig byggnad: Konstruktionsval för invändig förstärkningsstomme av trä2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The different counties in Sweden have been reporting about the increasing housingshortage in the country for a long time. To counteract this shortage, 60 000- 70 000residences need to be produced yearly in Sweden till 2029. In the 60s-70s Swedenalso faced big challenges with housing shortage due the urbanization from thecountryside of Sweden to the cities. The result was to build on a large scale in aIndustry-like ways and the consequences of this was that green areas around thecities were exploited to make room for new residential areas. To not repeat thehistory again an alternative option could be to densify the already built urbanenvironment with for example building extensions.In an already existing urban environment, there are many different types ofbuilding, this also means that there are many different types of extensions. Thepurpose of the work is to: for a reference house located in the central area of Falun,find an alternative way for a building extension in wood where the already existingbuilding is not added by any load from the extension. Another purpose with thework is therefore to contribute with knowledge around the subject, buildingextensions in wood.The building that has been the starting point of this work is located in the centralarena of Falun and was built in the late 60s. The building extension that the projectcame up with is of “light construction” and the reinforcement frame in massivewood technique with columns and beams. The reason why to use a real referenceobject is to give the work a real construction to relate to when analyzing thepossible placing of the columns. The dimensioning of the building extension andthe reinforcement frame is done with manual calculations that are based on theapplicable rules in Sweden, Eurocode and EKS. The building has also beenmodeled in Revit to give an illustration on the building extension with thereinforcement frame but also the building in its entirety after the buildingextension.The result of the reinforcement frame is in many ways similar to a “trä8”-system.Columns and beams take the vertical load and the existing buildings system ofjoist, walls and stairwells in concrete contribute to the frame stability. Throughanalyzing the drawing of the existing building, the placement of the columns hasbeen done according to different parameters. The beams that are placed on top ofthe columns have then been controlled for the current spans with the current loadsfrom the manual calculations of the building extension. The result and theconclusions that can be done from this work is that the construction's critical partis the beams placed on the columns and not the columns itself. The dimensions ofthe beams are crucial for how many floors that are possible to build on thecolumns that are placed. Also, the weight of the building extension has an impactin the quantity of the columns and therefor longest spans for the beams

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  • 4.
    Andersson, Julia
    et al.
    Dalarna University, School of Information and Engineering.
    Liedström, Matilda
    Dalarna University, School of Information and Engineering.
    Effekten av olika logistiklösningar: En studie kring fördelar och nackdelar med tredjepartslogistik och inbärning till ett projekt i Dalarna2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Within the construction industry the advantages of looking at the logistics todifferent projects has been acknowledged during the past couple of years.This study has been written in collaboration with Skanska Sverige AB. Thepurpose of the study is to, in different ways, examine what advantages anddisadvantages there are in using the logistics solutions terminalization (also knownto be a part of Third Party Logistics) and inside delivery to a specific project inDalarna, Sweden. This project is a remodeling project of a school with studentsfrom six to sixteen years old. Within the school area new parts of the school isbuilt while students are located in the yet existent buildings. This infer thatstudents move around the construction sites daily. The study also involves thirdparty people and how these people feel about the large transports connected to theproject. The inside delivery utility is then discussed based on the securityexperience within and around the construction site along with the economic andecological perspective of the service.The methods used in this study are interviews with three people of the projectmanagement, one person that works with logistics at the company, the headmasterof the younger students, skilled workers and third party people. Furthermore afield study is done that includes measurements and observations. As a close,calculations are done to determine if a economical profitability could be possibleby using inside delivery.Results from the study show how the logistics solutions terminalization and insidedelivery is looked at within Skanska today. Here, the advantages anddisadvantages with the different services are displayed from the perspectives of thepeople who were interviewed. The results from the measurements from the fieldstudy presents how many third party people that move adjacent to the two activeconstruction sites when the school day begins. The calculations show that it iseconomically beneficial to use inside delivery after the end of the workday whileused with terminalization.Conclusions of the study indicate that there are no overall solutions regarding howthe logistics must be used in different projects. If there is a possibility to use terminalization in the area where the project is situated, this, along with insidedelivery, is a good alternative for the project.

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  • 5.
    Bergkvist, Johanna
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Strandberg, Linda
    Dalarna University, School of Technology and Business Studies, Construction.
    En pedagogisk byggnad för hållbar utveckling: Utformning av en programhandling för ett kretsloppshus med fokus på social och ekologisk hållbarhet2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to establish a functional program for an eco-cycle building where people can be

    reached with knowledge of sustainable development. The background to this is that the municipality of

    Borlänge approved a plan program with the vision of creating a new, climate neutral district and thereby

    become a precursor for sustainable construction in the region. For instance, the functional program is meant

    to investigate the background and the prerequisites that existed. In the municipality’s plan program, the

    building is described to have an educational function for the district and for Borlänge; a place which focuses

    on practical demonstrations and education for students and residents in recycling issues for energy, water

    and waste/material in a comprehensible and compelling way. The eco-cycle building is planned to be

    established near the new school, with classes from 6 to 9, to make a cooperation possible.

    Requests from the municipality is that the eco-cycle building can work like a hub in the new district, but

    also become a new place of interest and put Borlänge on the map for sustainable construction. Sustainable

    construction includes resource management, minimized energy use and renewable energy sources, but also

    that resources like energy, waste and water circulate in an eco-cycle. Theory has been obtained from

    literature focusing on how we should build our houses and cities if we want to join and create a sustainable

    society.

    Part of the purpose of this thesis was to explore how to disseminate information on environmental and

    circular issues in an educational way. The theoretical part of the thesis is therefore focusing on selected parts

    of education obtained from previous research in children and youth learning for sustainable development,

    since studies show that it is important that children learn about these issues early in life. Education for

    Sustainable Development is an important prerequisite for achieving the sustainability goals set by the UN

    until 2030. Upcoming generations must learn a sustainable way of life right from the start while the existing

    population must drastically change their lifestyle.

    In order to gather empiricism, interviews were held with people who have been involved in the planning

    work with the new district. It turned out that there were former driving spirits who introduced the idea of the

    eco-cycle building, but that it doesn’t currently are the major priority in the ongoing work with the new

    school and housing.

    Engaging the users at an early stage provides better conditions for achieving a result that is effective and

    satisfying for all parties. The theory of design dialogues has therefore been studied to demonstrate the

    importance of a good dialogue to quickly identify needs and develop ideas in design work.

    The result of the thesis, the functional program, can be seen as a draft on conceptual level with features and

    expressions that can be applied to a building of this kind, and an inspiration for continued work. In the

    functional program, our interpretations form how the eco-cycle building would meet the requests and

    functions that’s been requested in the plan program, in order to benefit as much as possible in the

    municipality's future work with the building.

    Conclusions are that there are no precursors of the eco-cycle building as a concept. Despite a large number

    of sources of inspiration from various aspects, no example was found that combines all the aspects we have

    the ambition to develop for this building. The eco-cycle building as a concept could play an important role

    for how to handle sustainable issues in a district or in a whole city. However, further work is required to

    investigate how the building should be run and managed, as well as more extensive studies of which

    technical solutions to apply. Further work is also required to optimize the building for the future location,

    and the size of the building that are appropriate. There is a great interest in the building from various

    participants in Borlänge, but to implement the idea of the eco-cycle building, one or more people need to

    embrace the project with the commitment that previously existed in the organization.

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  • 6.
    Berglund, Gustaf
    et al.
    Dalarna University, School of Information and Engineering.
    Johnsson, Axel
    Dalarna University, School of Information and Engineering.
    Takstolslösningar i garagebyggnader med inredd vind.: Undvika pelare i garageutrymmen2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study focuses on possible roof truss solutions in garages with furnished attics. The text writers, on behalf of AB Karl Hedin whose customers' wishes have sometimes been difficult to achieve. This is because large spans are needed to create as large an area in the attic as possible. Customers also request the garage area to be completely open, namely. Without the carrying aid of, for example, pillars or partitions. There are many ways to erect conceivable rafters for garages with furnished attic, problems are added when the spans become too large. The problems are based on both material use, construction solutions and dimensions. To design a rafter at present time, the construction of construction requirements, loads and calculation models is controlled depending on the desired span of the rafters, as well as the area of use in the attic space. With the help of, among other things, literature study, calculations and analyses, proposals have been discussed on construction parts, materials and development opportunities for the rafters in question. Based on the chosen range, different solutions have been reviewed to achieve the best possible result. The calculations have shown that a collaborative support leg wall is a good method that extends the span up to 2m on a building. Steel carrying line has also proven to be a good construction solution that extends the span of the floor beams. With the chosen dimension of steel beam in this study, the depth of the building must be considered to meet the construction requirements regarding torque force and deflection. The properties of the materials and the intended methods for solving the problem of large spans have since been compared against each other to determine which method is best suited for the intended purpose. The material properties chosen for the comparison are the materials that the roof truss manufacturer currently has access to, which was a limitation for this study.

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  • 7. Birchall, Sarah
    et al.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Wallis, Ian
    Dipasquale, Chiara
    Bellini, Alessandro
    Fedrizzi, Roberto
    Survery and simulation of energy use in the European building stock2016Conference paper (Refereed)
    Abstract [en]

    the work towards increased energy efficiency. In order to plan and perform effective energy renovation of the buildings, it is necessary to have adequate information on the current status of the buildings in terms of architectural features and energy needs. Unfortunately, the official statistics do not include all of the needed information for the whole building stock.

     

    This paper aims to fill the gaps in the statistics by gathering data from studies, projects and national energy agencies, and by calibrating TRNSYS models against the existing data to complete missing energy demand data, for countries with similar climate, through simulation. The survey was limited to residential and office buildings in the EU member states (before July 2013). This work was carried out as part of the EU FP7 project iNSPiRe.

     

    The building stock survey revealed over 70% of the residential and office floor area is concentrated in the six most populated countries. The total energy consumption in the residential sector is 14 times that of the office sector. In the residential sector, single family houses represent 60% of the heated floor area, albeit with different share in the different countries, indicating that retrofit solutions cannot be focused only on multi-family houses.

     

    The simulation results indicate that residential buildings in central and southern European countries are not always heated to 20 °C, but are kept at a lower temperature during at least part of the day. Improving the energy performance of these houses through renovation could allow the occupants to increase the room temperature and improve their thermal comfort, even though the potential for energy savings would then be reduced.

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  • 8.
    Blomqvist, Stina
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Helgesson, Robin
    Dalarna University, School of Technology and Business Studies, Construction.
    Framtagning av yttervägg för småhus: En analys med hänsyn till kommande energikrav2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today is the specific requirements for the building’s energy use in new buildnings. These requirements come under the EU directive to be tightened firmly to the year 2020. This work was the basis of an interpretation of the coming energy requirements, 2020 requirements, designing a new energy-efficient exterior wall construction. This has been done with Fiskarhedenvillan and the construction has been valued in terms of material cost, assembly and the square meter price.

    By calculations and fact finding, demonstrated how energy in small houses could be reduced by replacing the insulating material to a material with lower heat conductivity. The method was to interpret the coming energy requirements and analyze Fiskarhedenvillan current wall construction. Next, search for information and facts about various insulation materials and then design a new proposal on the exterior wall construction.

    The outer wall construction is a crucial factor for the building envelope energy efficiency. Because Fiskarhedenvillan chosen to focus only on the outer wall, this work is delimited to that part of the building envelope.

    An important conclusion of this work is that the 2020 objectives can be met by improving the exterior wall construction and that it is possible to make a design that meets the requirements in entire Sweden

  • 9.
    Brinkebäck, Eric
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Jönsson, Johan
    Dalarna University, School of Technology and Business Studies, Construction.
    Fallstudie av moderna timmerhus: Kvalitetskontroll av nybyggda timmerhus mot FST:s kvalitetsnormer och BBR:s kommande energihushållningskrav2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A study has been conducted to investigate how log houses will meet the new requirements regarding U-value and specific energy use with primary energy factor as a basis, which will be put into use in 2017. In the study, two houses have been investigated. Both houses were constructed with 200 mm thick logs without any additional isolation. Both houses have geothermal heating systems. The study found that the new requirements will be rough against timber house constructions with geothermal or electricity as a heating system, since a primary energy figure of 1.6 will be multiplied by the total energy consumption when heated by electricity.

  • 10. Chai, Jiale
    et al.
    Huang, Pei
    City University of Hong Kong.
    Sun, Yongjun
    Climate change impact on energy balance of net-zero energy buildings in typical climate regions of China2019In: E3S Web of Conferences, E-ISSN 2267-1242, Vol. 111, article id 04004Article in journal (Refereed)
  • 11. Chai, Jiale
    et al.
    Huang, Pei
    City University of Hong Kong.
    Sun, Yongjun
    Investigations of climate change impacts on net-zero energy building lifecycle performance in typical Chinese climate regions2019In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 185, p. 176-189Article in journal (Refereed)
    Abstract [en]

    Net-zero energy building (NZEB) is widely considered as a promising solution to the current energy problem. The existing NZEBs are designed using the historical weather data (e.g. typical meteorological year-TMY). Nevertheless, due to climate change, the actual weather data during a NZEB’s lifecycle may differ considerably from the historical weather data. Consequently, the designed NZEBs using the historical weather data may not achieve the desired performances in their lifecycles. Therefore, this study investigates the climate change impacts on NZEB lifecycle performance (i.e., energy balance, thermal comfort and grid interaction) in different climate regions, and also evaluates different measures' effectiveness in mitigating the associated impacts of climate change. In the study, the multi-year future weather data in different Chinese climate regions are firstly generated using the morphing method. Then, using the generated future weather data, the lifecycle performances of the NZEBs, designed using the TMY data, are assessed. Next, to mitigate the climate change impacts, different measures are adopted and their effectiveness is evaluated. The study results can improve understanding of the climate change impacts on NZEB lifecycle performance in different climate regions. They can also help select proper measures to mitigate the climate change impacts in the associated climate regions.

  • 12. Chai, Jiale
    et al.
    Huang, Pei
    City University of Hong Kong.
    Sun, Yongjun
    Life-cycle analysis of nearly zero energy buildings under uncertainty and degradation impacts for performance improvements2019In: Energy Procedia, ISSN 1876-6102, Vol. 158, p. 2762-2767Article in journal (Refereed)
    Abstract [en]

    Sizing the nZEB systems properly is crucial for nZEBs to achieve the desired performances. The energy demand prediction uncertainties and the components’ degradation are two major factors affecting the nZEB systems sizing. The energy demand prediction has been studied by many researchers, but the impacts of degradation are still neglected in most studies. Neglecting degradation may lead to a system design that can perform as expected only in the beginning several years. This paper, therefore, proposes an uncertainty-based life-cycle performance analysis (LCPA) method to study the impacts of degradation on the nZEBs longitudinal performance. Based on the LCPA method, this study also proposes a two-stage method to enhance the nZEB system sizing. The study can enhance the designers’ understanding of the components’ degradation impacts. Case studies show that an nZEB might not achieve zero energy targets after years due to degradation. The proposed two-stage design method can effectively mitigate this problem.

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  • 13.
    Dellfjord, Veronica
    Dalarna University, School of Technology and Business Studies, Construction.
    Kunskap hos privatpersoner om fukt på kallvind2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    It is common that homeowners are recommended to add an insulation layer on the attic to lower building heating energy, however many do not realize the problem with complementary insulation compared to what the building and the building shell is adapted for. The lack of knowledge of the homeowners, can result in that they accidentally fill the longitudinal ventilation slits on the cold roof that is there to maintain the natural ventilation and prevent air from drying out any moisture.

    The aim is to find thus out:

    • How much knowledge do the homeowners have about the risk of moisture problems in the cold roof, and how to prevent future moisture damage in the best way, depending on the design of the roof?

    • Is there a risk of moisture problems for the objects studied, based on moisture measurements and high moisture content?

    The method chosen for the study was semi-structured interviews, containing sixteen questions, with homeowners and measurements of relative humidity of air and wood and the moisture content in the wood. The study was limited to the spring of 2016 and to four homeowners.

    It turned out to differ little among the interviewers on how much knowledge they had about moisture in cold roofs and how much knowledge they possess today. Some had enough knowledge to prevent moisture damage while others needed more information. Several felt that the insurance company is where they have to acquire information from, preferably in the form of a leaflet with short questions, sent out annually.

    The measurements proved to give good results with little risk of moisture damage to the cold roofs. There were no high moisture content in neither truss nor inside roof.

  • 14. Eriksson, Anna-Maria
    Energieffektivisering av klimatskal med hänsyn till kulturhistorisk värdering: Fallstudier av tre befintliga småhus från 1900-talet ur bevarandesynpunkt2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Increasingly stringent legal requirements make it difficult to energy efficiency in existing buildings without changing their appearance.

    The purpose of the study is to investigate how much energy, for three existing single-family homes built in the 1900s, which is achievable by improving the building envelope, ie, ceilings, walls, floors, windows and doors, without distorting the building's appearance and while maintaining their cultural values.

    The work consisted of a pilot study where three buildings were identified, a research stage where information about the buildings were developed and an inference stage where energy saving measures proposed were developed and evaluated. Buildings that were good representatives of their time and style sought. Buildings from the 1910s, 1930s and 1970s, was located. Since it was done case studies, interviews and surveys. To investigate the building envelope was conducted U-value calculations and energy calculations of the existing building commitment and buildings based on the proposed policy proposals.

    None of the buildings reached after the proposed action down to the passive house requirement 59 kWh/year/m2 Atemp or BBR requirement 110 kWh/year/m2 Atemp for a building-specific energy consumption. The maximum possible energy efficiency for the three buildings erected during the 1900s, which is achievable without corrupting the buildings' appearance while preserving their cultural values is 13.0 kWh/year/m2 Atemp, 49.7 kWh/year/m2 Atemp respectively 64.8 kWh/year/m2 Atemp.

    Conclusions of the work is that buildings from the 1910's can be addressed by isolating the windows, put one extra door on the inside of the front door and additional insulation in sloping roof. Buildings from the 1930s can be addressed by isolating windows with insulating glass on the inside of the windows and doors with an extra door on the inside of the front door. Buildings from the 1970s can fix the windows by changing them into energy windows, no action on the floor but the facade insulated externally with vacuum insulation. The building from the 1970s fared best in the comparison because it was the authentic condition from the beginning, which meant that the improvement was greater than for example the building from the 1910s that was already rebuilt before action was proposed.

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  • 15.
    Eriksson, Karolina
    Dalarna University, School of Information and Engineering.
    Energieffektivisering av en oisolerad torpargrund: En jämförelse mellan en Hasopor/skumglasgrund och två uteluftsventilerade grundkonstruktioner2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The majority of the about 400 000 small houses in Sweden that were built before 1930 have a mull bench or a crawl-space foundation as a basic structure, often completely or partially uninsulated with low energy performance as a result. In this thesis, a case study investigates which best-practice solutions there are to make an older crawl-space foundation more energy efficient and how a Hasopor/foam glassfoundation stands up to these solutions.

    The results shows that the Hasopor/foam glass foundation stands well up against the two competitors; two outdoor-air ventilated foundations that are modified in different ways. Construction 2 corresponds to the conventional standard solution and construction 3 an alternative interpretation of this. The Hasopor/foam glass is equivalent to construction 2 in terms of energy performance for a crawl-space foundation with similar conditions to the case study when the surface is larger than50m2. Based on these conditions, the U-value is in line with the target value as specified by BBR for renovation of existing ground foundations/floors. However, these target values must always be set against the requirement of caution and the ban on tampering which are also specified in the BBR. All of the investigated ground foundations can be introduced with regard to these requirements.

    The impact of the cold bridges on the Hasopor/foam glass foundation is an uncertain factor that needs further investigation. Likewise, the thickness of the Hasopor layer has a significant impact on the U-value. Furthermore, the thesis shows that a transition from an uninsulated crawl-space foundation to one of the investigated foundations can lead to an energy saving in the order of 80-90% of current energy loss from the ground foundation. 

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  • 16.
    Fiedler, Frank
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Persson, Jannika
    Dalarna University, School of Technology and Business Studies, Construction.
    Gustavsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Kovacs, Peter
    RISE.
    Hemlin, Olleper
    RISE.
    Ollas, Patrik
    RISE.
    Thuvander, Liane
    Chalmers Tekniska Högskolan.
    Femenías, Paula
    Chalmers Tekniska Högskolan.
    Lundin, Michelle
    Chalmers Tekniska Högskolan.
    Larsson, David
    Solkompaniet.
    Miljontak Delprojekt 2: Sammanfattning av litteratursammanställning2018Report (Other academic)
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  • 17. Gao, D. -C
    et al.
    Sun, Y.
    Zhang, Xingxing
    Dalarna University, School of Information and Engineering, Energy Technology.
    Huang, Pei
    Dalarna University, School of Information and Engineering, Energy Technology.
    Zhang, Yelin
    A GA-based NZEB-cluster planning and design optimization method for mitigating grid overvoltage risk2022In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 243, article id 123051Article in journal (Refereed)
    Abstract [en]

    Net-zero energy buildings (NZEBs) are considered as a promising method to mitigating the energy problems. Due to the intermittent characteristics of renewable energy (e.g., solar energy), NZEBs need to frequently exchange energy with the grid, which imposes severe negative impacts on the grid especially the overvoltage risk. Both planning and design are essential for reducing NZEB connected grid overvoltage, but most existing studies isolated the efforts from planning to design, thereby failing to achieve the best cumulative result. More importantly, existing studies oversimplified overvoltage quantification by using aggregated power interactions to represent overvoltage risk, which cannot consider the complex voltage influences among grid nodes. Due to the isolated efforts and the quantification oversimplification, existing studies can hardly achieve overvoltage risk minimization. Therefore, this study proposes a novel GA (genetic algorithm)-based method in which the key planning and design parameters are optimized sequentially for mitigating the overvoltage risk. Meanwhile, distribution network model has been adopted to precisely quantify the grid overvoltage. The study results show that the proposed method is highly effective in reducing NZEB cluster connected grid overvoltage risk. The proposed method can be used in practice for improving NZEB cluster planning and system design as grid interaction is considered. © 2021 Elsevier Ltd

  • 18.
    Garman, Ian
    et al.
    Dalarna University, School of Information and Engineering, Construction. Univ Gävle.
    Mattsson, Magnus
    Univ Gävle.
    Myhren, Jonn Are
    Dalarna University, School of Information and Engineering, Construction.
    Persson, Tomas
    Dalarna University, School of Information and Engineering, Energy Technology.
    Demand control and constant flow ventilation compared in an exhaust ventilated bedroom in a cold-climate single-family house2023In: Intelligent Buildings International, ISSN 1750-8975, E-ISSN 1756-6932Article in journal (Refereed)
    Abstract [en]

    A convertible, zoned ventilation system was field-tested in a modern, airtight Swedish home when occupied either by an experimental team or by a family. Indoor air quality in the master bedroom was monitored under four ventilation strategies. Relative to constant air volume strategies (CAV), demand-controlled ventilation (DCV) that was responding to CO2 concentration extracted more air when people were present, but less in total over 24 h. This elevated the indoor air humidity, beneficial in climates with dry winter air. Multiple monitors within the bedroom indicated that vertical CO2 stratification occurred routinely, presumably due to low mixing of supply air from a wall-mounted diffuse vent, spreading the air radially over the wall. This seemingly improved air quality in the breathing zone under local (ceiling) extract ventilation but worsened it during more typical, centralised extract ventilation, where air escapes the room via an inner doorway. The local extract arrangement thus seemed to yield both improved ventilation efficiency and reduced contaminant spread to other rooms. The noted air quality variations within the room highlight the importance of sensor placement in demand-control ventilated spaces, even in small rooms such as bedrooms.

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  • 19.
    Garman, Ian
    et al.
    Dalarna University, School of Information and Engineering, Construction.
    Mattsson, Magnus
    Persson, Tomas
    Dalarna University, School of Information and Engineering, Energy Technology.
    Ventilation alone fails to prevent overheating in a Nordic home field study2022In: 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022, Kuopio, 12 June 2022 through 16 June 2022, International Society of Indoor Air Quality and Climate , 2022Conference paper (Refereed)
    Abstract [en]

    A field study conducted in a modern Nordic single-family house with high airtightness and insulation levels, attempted to control summer indoor overheating using night-time cooling strategies. Exhaust air flow rates were manually scheduled by the researchers (based on weather forecasts), analogous to what an engaged occupant - or a predictive system - might do. Air temperatures at a nearby meteorological station peaked at 30 °C during 6 days in June that saw only 44 hours below 18 °C. Temperatures recorded indoors at the test house reached 32 °C, due also to very large solar gains, and never fell below 26 °C over 8 continuous days. It appears that under extended heat conditions that are exceptional now, but foreseen to become more frequent, some modern Nordic homes cannot be temperature controlled by ambient ventilation alone. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.

  • 20.
    Goldheim Jämthagen, Fredrik
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Reyier, Marcus
    Dalarna University, School of Technology and Business Studies, Construction.
    Behovsstyrning av ett småhus: Behovsstyrning av värme, ventilation, belysning och dess påverkan på energianvändningen i ett småhus2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    All people use some kind of energy to live. A disadvantage of this is that it has a

    impact on the climate, because energy consumption is greater than the Earth is

    capable of. Sweden has set a goal that energy use should be 20% more

    effective by year 2020. Boverket’s building rules have several instruments where

    energy use is greatly affected. Among other things, the energy performance is

    measured in primary energy. BBR provides guidelines for air turnover and flows.

    These affect the use of heating energy in a building. The rules makes a

    possibility of reducing flow and turnover when no need exists. In order to effect

    the use of energy in a building, demand control of energy systems can be used.

    The indoor climate can then be affected depending on whether people are in the

    room or not. The purpose of the study is to investigate differences in purchased

    energy between demand controlled and no demand controlled indoor climate. In

    order to assume a single-family house, the study was based on Dalarnas villa. It

    is a modern two-story house with large windows. The house is built between

    Borlänge and Falun. Demand control of a single house is a relatively unexplored

    area. RISE performs a study at the time of writing. They investigate the

    possibility of demand control ventilation in homes. In order to enable efficient

    demand control, several sensors and set points are required, as well as a

    control system that enables communication between the sensors. The test

    object was used to calculate energy use with different grade of demand control.

    The calculations were performed in three different ways to verify the result.

    These three were: hand calculation, TMF energi 7.11 and IDA ICE. The different

    ways consider different parameters and data. With IDA ICE, a theoretical model

    was built and several simulations were performed. The results of the calculations

    differ relatively slight between the different calculations. What all the calculations

    indicate is that there is a possibility for reducing energy use with demand

    control. When lighting, heating and ventilation are controlled, a reduction of 26 %

    (exclude hot water and equipment electricity) in energy consumption can be

    achieved by using demand control. This is due to the fact that heat loss is

    effectively reduced with less airflow and lower indoor temperature when no

    person is present in the room. The possibility of demand control in this small

    house is seen to be good, but in order to have an efficient demand control, a

    well-adjusted control system is required.

  • 21.
    Gustafsson, Elina
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Persson, Jannika
    Dalarna University, School of Technology and Business Studies, Construction.
    Miljövänliga material i villakonstruktion: En jämförande studie av fyra olika vägg- och vindsbjälklagsförslag gällande miljö och hälsa, med fuktanalys och U-värdesberäkningar.2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Environmental awareness today is larger than ever, and continues to expand. The increasing knowledge has led to a rising demand of using environmental friendly materials and the interest of building and living in a way that is good for the health and environment has grown with it. The small house manufacturer Fiskarhedenvillan, has noticed this demand and that is why this study has been done.

    The purpose of this study is to investigate what opportunities there is to replace one or some of the chosen materials from Fiskarhedenvillans construction to materials that fulfills higher demands at being environment- and healthfriendly. The U-value of the suggestions should be equivalent or improved. The most important aspect otherwise was to investigate how well the new suggestions manage moisture impact. The suggested materials have been windbarrier board, insulation, waterproofing, vapour barrier, tape and interior lining.

    The study was performed by a thorough investigation of the materials that could be of interest. This was done by searching for relevant information through databases, reports, manufacturers homepages and from other construction related books and internet sources. The moisture simulations and U-value calculations were done in the simulation program WUFI pro 5.3. A survey was sent out to Fiskarhedenvillans agents to investigate the housing markets interest in changing to environmental-friendly materials.

    The investigations resulted in four functional suggestions on external wall construction with loft floor, which was chosen based on the purposes. The results show that all constructions successfully handled the moisture exposure, except the wallconstruction with cellulose based insulationboards, where the relative humidity during the whole year stays at such high levels that risk of mould- and moisturedamage is existing. The result of the U-value calculations shows that the suggestions have similar U-value to Fiskarhedenvillans current constructions. However, the proposal with hempinsulation had to be extended 10cm in order to meet this requirement. For the loft floor with hempinsulation it was accepted that the U-value was somewhat lesser than the others. The result from the survey shows that more than half of the agents have experienced a demand from potential customers to change materials to more environment-friendly.

    The most important conclusion is that it is possible to change materials in a house and maintain its construction capacity while managing the impact of moisture as well. Since customers appear willing to pay more for changing materials, we believe that it would not be a problem for Fiskarhedenvillan to establish at least one construction possibility with environmental-friendly materials.

  • 22.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH, Strömnings- och klimatteknik.
    Energy Efficient Renovation Strategies for Swedish and Other European Residential and Office Buildings2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The high energy use in the European building stock is attributable to the large share of old buildings with poor energy performance. Energy renovation of buildings is therefore vital in the work towards energy efficiency and reduced environmental impact in the EU. Yet, the strategies and energy system implications of this work have not been made clear, and the rate of building renovation is currently very low.

    The aim of this thesis is to investigate the economic and environmental aspects of energy renovation strategies, with two main objectives:

    • Renovation of Swedish district heated multi-family houses, including life-cycle cost and environmental analysis and impact on the local energy system;

    • Renovation of European residential and office buildings, including life-cycle cost and environmental analysis and influence of climatic conditions.

    Buildings typical for the respective regions and the period of construction 1945-1970 were simulated, in order to determine the feasibility and energy saving potential of energy renovation measures in European climates. A variety of systems for heating, cooling and ventilation were studied, as well as solar energy systems, with focus on heat pumps, district heating, low-temperature heating systems and air heat recovery.

    Compared to normal building renovation, energy renovation can often reduce the life-cycle costs and environmental impact. In renovation of typical European office buildings, as well as Southern European multi-family houses, more ambitious renovation levels can also be more profitable.

    Exhaust air heat pumps can be cost-effective complements in district heated multi-family houses, while ventilation with heat recovery is more expensive but also more likely to reduce the primary energy use. From a system perspective, simple exhaust ventilation can reduce the primary energy use in the district-heating plant as much as an exhaust air heat pump, due to the lower electricity use.

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  • 23.
    Gustafsson, Marcus
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Poppi, Stefano
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fedrizzi, Roberto
    Dipasquale, Chiara
    Bellini, Alessandro
    Ochs, Fabian
    Univeristy of Innsbruck.
    Dermentzis, Georgios
    Univeristy of Innsbruck.
    Performance of Studied Systemic Renovation Packages – Office Buildings2016Report (Other academic)
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  • 24.
    Hahne, Felix
    et al.
    Dalarna University, School of Information and Engineering.
    Blank, Filip
    Dalarna University, School of Information and Engineering.
    Bärande innerväggar av KL-trä, armerad betong och oarmerad betong i flerbostadshus: Jämförelse av koldioxidutsläpp och kostnader för lägenhetsavskiljande samt icke lägenhetsavskiljande väggar2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study presents a comparison between CLT and various kinds of concrete (reinforced/unreinforced and cast in place versus prefabricated) as wall material in building constructions. The purpose is to analyse their respective environmental impact and cost efficiency. Despite an initially higher cost per square meter CLT has a considerably lower environmental impact, which entails a net profit for the environment compared to the concrete walls. Among the concrete options, walls without rebar and cast in place exhibits a balance between lower costs and CO2eemissions. This study highlights the need of standardized, trustworthy data of the environmental impact in the construction industry to support sustainable decisions. It points to the potential in further research which intends to reduce both cost and environmental impact for CLT, to further promote its use in the construction industry. The study thus offers important insights for driving a more sustainable and economically profitable construction industry.

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  • 25.
    Han, Mengjie
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    May, Ross
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wang, Xinru
    Pan, Song
    Da, Yan
    Jin, Yuan
    A novel reinforcement learning method for improving occupant comfort via window opening and closing2020In: Sustainable cities and society, ISSN 2210-6707, Vol. 61, article id 102247Article in journal (Refereed)
    Abstract [en]

    An occupant's window opening and closing behaviour can significantly influence the level of comfort in the indoor environment. Such behaviour is, however, complex to predict and control conventionally. This paper, therefore, proposes a novel reinforcement learning (RL) method for the advanced control of window opening and closing. The RL control aims at optimising the time point for window opening/closing through observing and learning from the environment. The theory of model-free RL control is developed with the objective of improving occupant comfort, which is applied to historical field measurement data taken from an office building in Beijing. Preliminary testing of RL control is conducted by evaluating the control method’s actions. The results show that the RL control strategy improves thermal and indoor air quality by more than 90 % when compared with the actual historically observed occupant data. This methodology establishes a prototype for optimally controlling window opening and closing behaviour. It can be further extended by including more environmental parameters and more objectives such as energy consumption. The model-free characteristic of RL avoids the disadvantage of implementing inaccurate or complex models for the environment, thereby enabling a great potential in the application of intelligent control for buildings.

  • 26.
    Han, Mengjie
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    May, Ross
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wang, Xinru
    Pan, Song
    Yan, Da
    Jin, Yuan
    A novel reinforcement learning method for improving occupant comfort via window opening and closingManuscript (preprint) (Other academic)
  • 27.
    Han, Mengjie
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    May, Ross
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wang, Xinru
    Pan, Song
    Yan, Da
    Jin, Yuan
    Xu, Liguo
    A review of reinforcement learning methodologies for controlling occupant comfort in buildings2019In: Sustainable cities and society, ISSN 2210-6707, Vol. 51, article id 101748Article in journal (Refereed)
  • 28.
    Hansols, August
    et al.
    Dalarna University, School of Information and Engineering.
    Hagström, Fredrik
    Dalarna University, School of Information and Engineering.
    Återbruk av konstruktionsvirke till KL-trä: Vilka faktorer kan påverka producenterna att inte återanvända material inom produktion av KL-trä?2023Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    Korslimmat trä är sammansättning av virke som limmats ihop med varandra åt olika håll för att öka hållfastheten. KL-trä används vid tillverkning av småhus, flerfamiljshus, ridhus och andra större lokaler. Att arbeta med trä är idag ett aktuellt ämne då det är ett miljövänligare val än att till exempel använda sig utav betong. Syftet med studien är att undersöka om producenterna kan använda sig av återbrukat material vid tillverkningen av KL-träelement. Utifrån intervjuer samt litteraturstudier kunde följande slutsatser utläsas:

    • Produktion av KL-trä med återbrukat material inte stödjs på grund avföljande saker:

    o Nya standarder behöver arbetas fram

    o Producenter måste kunna lämna garanti på produkt

    o Slutkundens säkerhet måste beaktas

    • Återbrukat material kan användas i de lager som ej utgör huvudbärriktning med nästan lika gott resultat som jungfrulig råvara.

    • Potential finns att minska användningen av jungfrulig råvara med upp till 30% genom att använda återbrukat material i de lager som ej utgör huvudbärriktning.

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  • 29. Hedman, Åsa
    et al.
    Rehman, Hassam U.
    Gabaldón, Andrea
    Bisello, Adriano
    Albert-Seifried, Vicky
    Zhang, Xingxing
    Dalarna University, School of Information and Engineering, Energy Technology.
    Guarino, Francesco
    Grynning, Steinar
    Eicker, Ursula
    Reda, Francesco
    IEA EBC Annex83 Positive Energy Districts2021In: Buildings, E-ISSN 2075-5309, Vol. 11, no 3Article in journal (Refereed)
    Abstract [en]

    At a global level, the need for energy efficiency and an increased share of renewable energy sources is evident, as is the crucial role of cities due to the rapid urbanization rate. As a consequence of this, the research work related to Positive Energy Districts (PED) has accelerated in recent years. A common shared definition, as well as technological approaches or methodological issues related to PEDs are still unclear in this development and a global scientific discussion is needed. The International Energy Agency’s Energy in Buildings and Communities Programme (IEA EBC) Annex 83 is the main platform for this international scientific debate and research. This paper describes the challenges of PEDs and the issues that are open for discussions and how the Annex 83 is planned and organized to facilitate this and to actively steer the development of PEDs major leaps forward. The main topics of discussion in the PED context are the role and importance of definitions of PEDs, virtual and geographical boundaries in PEDs, the role of different stakeholders, evaluation approaches, and the learnings of realized PED projects.

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  • 30.
    Hernandez Velasco, Marco
    Dalarna University, School of Information and Engineering, Energy Technology.
    Enabling Year-Round Cultivation in the Nordics-Agrivoltaics and Adaptive LED Lighting Control of Daily Light Integral2021In: Agriculture, E-ISSN 2077-0472, Vol. 11, no 12, p. 1255-1255Article in journal (Refereed)
    Abstract [en]

    High efficacy LED lamps combined with adaptive lighting control and greenhouse integrated photovoltaics (PV) could enable the concept of year-round cultivation. This concept can be especially useful for increasing the production in the Nordic countries of crops like herbaceous perennials, forest seedlings, and other potted plants not native of the region, which are grown more than one season in this harsh climate. Meteorological satellite data of this region was analyzed in a parametric study to evaluate the potential of these technologies. The generated maps showed monthly average temperatures fluctuating from −20 °C to 20 °C throughout the year. The natural photoperiod and light intensity also changed drastically, resulting in monthly average daily light integral (DLI) levels ranging from 45–50 mol·m−2·d−1 in summer and contrasting with 0–5 mol·m−2·d−1 during winter. To compensate, growth room cultivation that is independent of outdoor conditions could be used in winter. Depending on the efficacy of the lamps, the electricity required for sole-source lighting at an intensity of 300 µmol·m−2·s−1 for 16 h would be between 1.4 and 2.4 kWh·m−2·d−1. Greenhouses with supplementary lighting could help start the cultivation earlier in spring and extend it further into autumn. The energy required for lighting highly depends on several factors such as the natural light transmittance, the light threshold settings, and the lighting control protocol, resulting in electric demands between 0.6 and 2.4 kWh·m−2·d−1. Integrating PV on the roof or wall structures of the greenhouse could offset some of this electricity, with specific energy yields ranging from 400 to 1120 kWh·kW−1·yr−1 depending on the region and system design.

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  • 31.
    Hersvall, Jacob
    Dalarna University, School of Technology and Business Studies, Construction.
    Tillämpning av Tekla Structura lDesigner: Enstudie med fokus på integration med Tekla Structural Designer som dimensioneringsverktyg2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, several 3D-Cad programs are used based on BIM application where detailed designs can be modeled to produce construction documents and manufacturing drawings around the engineering offices in Sweden. However, many of these programs are not compatible with 3D design and analysis software, but unnecessary work is required to draw a model several times to make the necessary calculations. The purpose of this degree project was to focus on the compatibility between Tekla Structural Designer and Tekla Structures, which also explored the ease of use of Tekla Structural Designer. The implementation was divided into two case studies, with the first focusing on the compatibility of a finished project model created in Tekla Structures as well as a separate model made in Tekla Structural Designer. In the second case study, the user-friendliness of the program was investigated in which the report describes how the user can utilize the most common features of the program. Based on case studies, they resulted in the compatibility between Tekla Structures and Tekla Structural Designer in both directions, although there are some limitations. An important conclusion from the work is that a model should preferably be projected with regard to being analytically correct before exporting from Tekla Structures. This in order to reduce hand laying at a later stage when the construction is to be analyzed. The application of Tekla Structural designs could lead to a more efficient working methodology within the projects. It could also lead to a closer relationship between projectors and those who perform the calculation when the projectors modeling models also have to think that the model should be analytically correct and be able to determine how elements etc. should be attached fixed or pinned. Furthermore, the program is considered useful in both modeling and analysis of a construction. Integration with several BIM software such as Autodesk Revit means that the application can be applied in several different projects

  • 32.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Augenbroe, Godfried
    Huang, Gongsheng
    Sun, Yongjun
    Investigation of maximum cooling loss in a piping network using Bayesian Markov Chain Monte Carlo method2019In: Journal of Building Performance Simulation, Taylor & Francis, ISSN 1940-1493, E-ISSN 1940-1507, Vol. 12, no 2, p. 117-132Article in journal (Refereed)
  • 33.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Huang, Gongsheng
    City University of Hong Kong.
    Building Automation for Energy Efficiency2019In: Handbook of Energy Efficiency in Buildings: A Life Cycle Approach / [ed] Umberto Desideri, Francesco Asdrubali, United Kingdom: Butterworth-Heinemann, 2019, 1, p. 627-649Chapter in book (Refereed)
    Abstract [en]

    In this chapter, the authors introduce current building energy management system (BEMS) from its development, current structure and main components, communications and standards, main functions and benefits, as well as future development trends. The information in this chapter can guide the readers in the direction of understanding, operation, and design of BEMS

  • 34.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Huang, Gongsheng
    Investigation of maximum cooling loss uncertainty in piping network using Bayesian Markov Chain Monte Carlo method2017In: Energy Procedia, ISSN 1876-6102, Vol. 143, p. 258-263Article in journal (Refereed)
    Abstract [en]

    Heating, Ventilation, and air-conditioning (HVAC) systems have been widely equipped in modern buildings to provide thermal comfort and acceptable indoor air quality, and always represent the largest primary energy end-use. As reported by many researchers, the cooling loss is prevalent in HVAC systems during cooling transmission from cooling sources (chillers) to cooling end-users (conditioning zones), and in some cases, it may even account for as high as 55% of the system total heat flow. At the design stage of an HVAC system, incomplete understanding of the cooling loss may lead to improper sizing of the HVAC system, which may result in additional energy consumption/economic cost (if oversized) or cause insufficient thermal comfort problems (if undersized). Therefore, the cooling loss in a typical HVAC system is significant, and it should be considered in the HVAC system sizing. For HVAC system sizing or retrofit, although there are many studies in the uncertainty in predicting the building peak cooling load, the uncertainty associated with the maximum cooling loss of the HVAC systems are still neglected. Therefore, this study proposes a study to investigate the uncertainty associated with the key parameters in predicting the maximum cooling loss in the HVAC systems using the Bayesian Markov Chain Monte Carlo method. The prior information of the uncertainty together with the available in-situ data is integrated to infer more informative posterior description of the uncertainty. The studied uncertain parameters can either be used for retrofit analysis or be used for prediction of the HVAC system performance. Details of the proposed methodology are illustrated by applying it to a real HVAC system.

  • 35.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Huang, Gongsheng
    Augenbroe, Godfried
    Sizing heating, ventilating, and air-conditioning systems under uncertainty in both load-demand and capacity-supply side from a life-cycle aspect2017In: Science and Technology for the Built Environment, ISSN 2374-4731, E-ISSN 2374-474X, Vol. 23, no 2, p. 367-381Article in journal (Refereed)
  • 36.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Huang, Gongsheng
    Augenbroe, Godfried
    Li, Shan
    Optimal configuration of multiple-chiller plants under cooling load uncertainty for different climate effects and building types2018In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 158, p. 684-697Article in journal (Refereed)
    Abstract [en]

    Configuring the number and size of chillers in a multiple-chiller plant properly is an efficient way to improve the plant energy efficiency. At the design stage, the optimal configuration can be achieved through matching the capacity to load as closely as possible across the full-load profile. However, in spite of the fact that current literature offers practical recommendations, a systematic method to optimize the configuration of multiple-chiller plants is lacking. Due to the lack of accurate information at the design stage and only limited knowledge of the eventual realization it is hard to predict the building’s cooling load. Moreover, there is no operational data to predict the system performance. Both explain the existence of uncertainty in the HVAC plant design process. This paper, therefore, proposes a strategy to optimize the configuration of multiple-chiller plants, which takes account of the load side uncertainty as well as the COP uncertainty and selects the optimal configuration through a life-cycle analysis. Both the load side uncertainty and the COP uncertainty are quantified using statistical distributions. To facilitate applications, the distributions of the cooling load profile of different types of buildings under different weather conditions are investigated and are classified into four categories, and the optimal configuration schemes under each type of cooling load distribution are analyzed and summarized in a tabulated form.

  • 37.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Huang, Gongsheng
    Sun, Yongjun
    A robust design of nearly zero energy building systems considering performance degradation and maintenance2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 163, p. 905-919Article in journal (Refereed)
    Abstract [en]

    Nearly zero energy buildings (nZEBs) are considered as a promising solution to mitigate the energy and environmental problems. A proper sizing of the nZEB systems (e.g. HVAC systems, PV panels, wind turbines and batteries) is essential for achieving the desirable level of thermal comfort, energy balance and grid dependence. Parameter uncertainty, component degradation and maintenance are three crucial factors affecting the nZEB system performances and should be systematically considered in system sizing. Until now, there are some uncertainty-based design methods been developed, but most of the existing studies neglect component degradation and maintenance. Due to the complex impacts of degradation and maintenance, proper sizing of nZEB systems considering multiple criteria (i.e. thermal comfort, energy balance and grid dependence) is still a great challenge. This paper, therefore, proposes a robust design method of nZEB systems using genetic algorithm (GA) which takes into account the parameter uncertainty, component degradation and maintenance. The nZEB life-cycle cost is used as the fitness function, and the user’ performance requirements on thermal comfort, energy balance and grid dependence are defined as three constraints. This study can help improve the designers’ understanding of the impacts of uncertainty, degradation, and maintenance on the nZEB life-cycle performances. The proposed method is effective in minimizing the nZEB life-cycle cost through designing the robust optimal nZEB systems sizes and planning the optimal maintenance scheme, meanwhile satisfying the user specified constraints on thermal comfort, energy balance, and grid dependence during the whole service life.

  • 38.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Huang, Gongsheng
    Sun, Yongjun
    Uncertainty-based life-cycle analysis of near-zero energy buildings for performance improvements2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 213, p. 486-498Article in journal (Refereed)
    Abstract [en]

    Near-zero energy buildings (nZEBs) are considered as an effective solution to mitigating CO2 emissions and reducing the energy usage in the building sector. A proper sizing of the nZEB systems (e.g. HVAC systems, energy supply systems, energy storage systems, etc.) is essential for achieving the desired annual energy balance, thermal comfort, and grid independence. Two significant factors affecting the sizing of nZEB systems are the uncertainties confronted by the building usage condition and weather condition, and the degradation effects in nZEB system components. The former factor has been studied by many researchers; however, the impact of degradation is still neglected in most studies. Degradation is prevalent in energy components of nZEB and inevitably leads to the deterioration of nZEB life-cycle performance. As a result, neglecting the degradation effects may lead to a system design which can only achieve the desired performance at the beginning several years. This paper, therefore, proposes a life-cycle performance analysis (LCPA) method for investigating the impact of degradation on the longitudinal performance of the nZEBs. The method not only integrates the uncertainties in predicting building thermal load and weather condition, but also considers the degradation in the nZEB systems. Based on the proposed LCPA method, a two-stage method is proposed to improve the sizing of the nZEB systems. The study can improve the designers’ understanding of the components’ degradation impacts and the proposed method is effective in the life-cycle performance analysis and improvements of nZEBs. It is the first time that the impacts of degradation and uncertainties on nZEB LCP are analysed. Case studies show that an nZEB might not fulfil its definition at all after some years due to component degradation, while the proposed two-stage design method can effectively alleviate this problem.

  • 39.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Huang, Gongsheng
    Wang, Yu
    HVAC system design under peak load prediction uncertainty using multiple-criterion decision making technique2015In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 91, p. 26-36Article in journal (Refereed)
    Abstract [en]

    Heating, ventilation and air-conditioning (HVAC) systems are widely equipped in modern buildings to provide indoor thermal comfort and guarantee indoor air quality. In a conventional design, the components of an HVAC system are sized according to a deterministic peak load, predicted according to typical weather condition, building physics and internal load. It has been shown by many studies that this prediction is associated with uncertainties since building physical parameters cannot be accurately set and the weather and the internal load used in the design may be different from the real situation after use. Therefore, uncertainty cannot be neglected in order to properly size a HVAC system. In this paper, a prototype of HVAC system design under uncertainty is proposed, which is able to take uncertainty directly in the design, and most importantly it can assess the performance of a design at the design stage in term of multiple performance indices and the customers’ requirements and preferences, i.e. the new design method falls in the framework of multiple criteria decision making. Case studies are used to illustrate the design procedure, and the result is compared with that of a conventional design method.

  • 40.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Sun, Yongjun
    A clustering based grouping method of nearly zero energy buildings for performance improvements2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 235, p. 43-55Article in journal (Refereed)
    Abstract [en]

    Collaborations among nearly zero energy buildings (nZEBs) (e.g. renewable energy sharing) can improve nZEBs’ performance at the community level. To enable such collaborations, the nZEBs need to be properly grouped. Grouping nZEBs with similar energy characteristics merely brings limited benefits due to limited collaboration existed, while grouping nZEBs with diverse energy characteristics can bring more benefits. In the planning of nZEB communities, due to the large diversity of energy characteristics and computation complexity, proper grouping that maximizes the collaboration benefits is difficult, and such a grouping method is still lacking. Therefore, this paper proposes a clustering based grouping method to improve nZEB performance. Using the field data, the grouping method first identifies the representative energy characteristics by advanced clustering algorithms. Then, it searches the optimal grouping alternative of these representative profiles that has the optimal performance. For validation, the proposed grouping method is compared with two cases (the nZEBs are either not grouped or randomly grouped) in aspects of economic costs and grid interaction. The study results demonstrate that the proposed method can effectively improve nZEBs’ performances at the community level. The propose method can provide the decision makers a means to group nZEBs, which maximize the collaboration benefits and thus assists the planning of nZEB communities.

  • 41.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Sun, Yongjun
    A collaborative demand control of nearly zero energy buildings in response to dynamic pricing for performance improvements at cluster level2019In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 174, p. 911-921Article in journal (Refereed)
    Abstract [en]

    Collaborations (e.g. renewable energy sharing) among nearly zero energy buildings can improve performances at cluster level. Demand response control is helpful to enable such collaborations. Existing studies have developed some dynamic pricing demand response control methods to reduce the nearly zero energy building cluster’ electricity bills and eliminate the power grid's undesirable peaks. However, in these controls the collaborations among buildings are not allowed/enabled, since each building interacts with the grid and there is no direct interaction among buildings. Meanwhile, for performance optimizations at building cluster level, the computation costs of these non-collaborative controls are excessively high especially as a number of buildings considered. Therefore, this study proposes a collaborative demand response of nearly zero energy buildings in response to dynamic pricing for cluster-level performance improvements. Considering the building cluster as one ‘lumped’ building, in which the renewable generations, energy demands and battery capacities of individual buildings are aggregated, the collaborative control first identifies the optimal performance at cluster level in response to the dynamic pricing. Then, based on the identified optimal performance, the proposed control coordinates individual buildings' operations using non-linear programming, thereby realizing the collaborations. For validation, the proposed collaborative demand response control is compared with a game-theory based non-collaborative demand response control. The developed control effectively reduces the cluster-level peak energy exchanges and electricity bills by 18% and 45.2%, respectively, with significant computational load reduction. This study will provide the decision makers a computation-efficient demand response control of nearly zero energy buildings which enables full collaborations and thus helps improve the performances.

  • 42.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Sun, Yongjun
    A robust control of nZEBs for performance optimization at cluster level under demand prediction uncertainty2019In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 134, p. 215-227Article in journal (Refereed)
    Abstract [en]

    Collaborations among nZEBs (e.g. renewable energy sharing and battery sharing) can improve the nZEBs' performance at the cluster level. To enable such collaborations, existing studies have developed many demand response control methods to control the operation of nZEB systems. Unfortunately, due to lack of consideration of demand prediction uncertainty, most of the demand response control methods fail to achieve the desired performance. A few methods have considered the impacts of uncertainty, but they merely perform simple and limited collaborations among nZEBs, and thus they cannot achieve the optimal performance at the cluster level. This paper, therefore, proposes a nZEB control method that enables full collaborations among nZEBs and takes account of the demand prediction uncertainty. The proposed robust control method first analyzes the demand prediction uncertainty, next optimizes the nZEB cluster operation under uncertainty, and then coordinates single nZEB's operation using the cluster operational parameters. The performance of the robust control has been studied and compared with a deterministic control. Case studies show that the robust control can effectively increase the cluster load matching and reduce the grid interaction with the demand prediction uncertainty existed. The proposed method can achieve robust performance improvements for the nZEB cluster in practice particularly as uncertainty exists.

  • 43.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Wang, Yu
    Huang, Gongsheng
    Augenbroe, Godfried
    Investigation of the ageing effect on chiller plant maximum cooling capacity using Bayesian Markov Chain Monte Carlo method2016In: Journal of Building Performance Simulation, Taylor & Francis, ISSN 1940-1493, E-ISSN 1940-1507, Vol. 9, no 5, p. 529-541Article in journal (Refereed)
  • 44.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Wang, Yu
    Sun, Yongjun
    Huang, Gongshend
    Review of uncertainty-based design methods of central air-conditioning systems and future research trends2019In: Science and Technology for the Built Environment, ISSN 2374-4731, E-ISSN 2374-474X, Vol. 25, no 7, p. 819-835Article in journal (Refereed)
  • 45.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Wu, Hunjun
    Huang, Gongsheng
    Sun, Yongjun
    A top-down control method of nZEBs for performance optimization at nZEB-cluster-level2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 159, p. 891-904Article in journal (Refereed)
    Abstract [en]

    Nearly zero energy buildings (NZEBs) are considered as a promising solution to the mitigation of the energy problems. A proper control of the energy system operation of the nZEB cluster is essential for improving load matching, reducing grid interaction and reducing energy bills. Existing studies have developed many demand response control methods to adjust the operation of energy systems to improve performances. Most of these studies focus on optimizing performances at individual-nZEB-level while neglecting collaborations (e.g. energy sharing and battery sharing) between nZEBs. Only a few studies consider the collaborations and optimize the system operation at nZEB-cluster-level, yet they cannot take full advantage of nZEB collaborations as optimization is conducted in a bottom-up manner lacking global coordination. This paper, therefore, proposes a top-down control method of nZEBs for optimizing performances at the cluster level. The top-down control method first considers the nZEB cluster as ‘one’ and optimizes its energy system operation using the genetic algorithm (GA), and then it coordinates the operation of every single nZEB inside the cluster using non-linear programming (NLP). The top-down control enables collaborations among nZEBs by coordinating single nZEB's operations. Such collaborations can bring significant performance improvements in different aspects. For instance, in aspect of economic cost, the collaborations can reduce the high-priced energy imports from the grid by sharing the surplus renewable energy with nZEBs which have insufficient energy generations. The proposed top-down control has been compared with a traditional non-collaborative control. The study results show that the top-down control is effective in improving performances at cluster level.

  • 46. Hussain, Syed Asad
    et al.
    Wang, Lan
    Huang, Pei
    Dalarna University, School of Information and Engineering, Energy Technology.
    Sadiq, Rehan
    Hewage, Kasun
    Dissimilarity-driven ensemble model-based real-time optimization for control of building HVAC systems2022In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 52, article id 104376Article in journal (Refereed)
    Abstract [en]

    Model-based real-time optimization (MRTO) is proven as an effective tool that can capture the complex dynamics of heating, ventilation, and air conditioning (HVAC) systems and improve its energy performance. Despite the energy benefits offered by MRTO, these approaches are rarely implemented in actual buildings. This is due to the reason that these approaches are very difficult to implement because they require the synthesis of a reliable and accurate performance model of the system. The reliability of decision-making with MRTO is directly related to the accuracy of these performance models. In addition, the model has to be computationally efficient for practical implementation. The development of such a model requires the most effort and is a major challenge in the implementation of MRTO. Several HVAC performance models are already available in the literature, and these can be classified as semiphysical models and data-driven models. The semiphysical models are generalized models with simplification assumptions that can provide consistent performance, however, with reduced accuracy. Contrastingly, the data-driven models can offer better accuracy; however, they lack robustness in terms of operational ranges. These factors affect the energy performance of MRTO, and an improper parametrized model could result in performance that is even worse than the conventional fixed setpoint or rule-based approaches. A dissimilarity-driven ensemble model-based real-time optimization (DEMRTO) approach is presented in this study that incorporates a dissimilarity-driven ensemble model in the framework of real-time optimization. The dissimilarity-driven ensemble model combines semiphysical models and data-driven models in a systematic manner to use one's strengths to address others' weaknesses, rather than developing a new form of a model. The performance of the proposed integrated approach was examined using case studies over three weather seasons in Hong Kong. The results showed as compared to the fixed setpoint approach the DEMRTO approach can provide significant energy savings up to 11.085% setpoint, and around 2.785% reduction in energy use as compared with the conventional MRTO approach. It was demonstrated that the proposed approach can capture diversity in load conditions and provide consistency in model prediction to improve reliability in decision-making with real-time optimization.

  • 47.
    Istiqamah, Istiqamah
    et al.
    Dalarna University, School of Information and Engineering.
    Shahraki, Sina Soleimani
    Dalarna University, School of Information and Engineering.
    Comparative Life CycleAssessment of Two Single Family Dwellings2022Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study compared the Global Warming Potential (GWP) impact of two single-family dwellings situated in Halmstad and Norrköping. The aim of this thesis work is to investigate how building materials types, material quantities, and geographical boundaries affect the Life Cycle Assessment (LCA) results. This study focuses on climate declaration (A1-A5) LCA stages and was conducted in collaboration with Fiskarhedenvillan.

    The study uses a comparative LCA of various building components and materials. One Click LCA student license was used to calculate the CO2e emissions from the GWP impact category.

    The study found that the building in Halmstad generated 6,3% lower CO2e emissions compared to the building in Norrköping. The reason mainly was affected by the use of roofing materials. The building in Halmstad used reinforced bitumen while the building in Norrköping used concrete tile roofing. The study investigates that reinforced bitumen generates lower emissions in A1-A4 stages compared to concrete.

    The geographical boundaries affect the A4 stage. The building in Halmstad generated higher CO2e emissions compared to the building in Norrköping as it has long distances to the building materials suppliers. The research verifies that the A1-A3 stages considerably generate most of the emissions (70-80%) compared to A4 and A5. The A5 stage results remain the same per meter square of both dwellings considering the use of generic data from One Click LCA.

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  • 48.
    Janols, Henrik
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Wik, Tina
    Dalarna University, School of Technology and Business Studies, Construction.
    Nulägesanalys av passivhusbyggande i Sverige 20102012Report (Other academic)
    Abstract [sv]

    Byggsektorn slukar årligen ca 40 % av Sveriges totala energiförbrukning. Nya normer kräver energieffektivare bostäder. Normerna idag fokuserar enbart på driftkostnader och tar inte alls hänsyn till energiförbrukningen och koldioxidavtrycket som själva byggprocessen alstrar. Med höga driftvärden blir energiförbrukningen i byggskedet en liten procent men för passivhus, och ännu högre grad för plusenergihus, som förbrukar ytterst lite energi, blir tillverkningsenergin den avgörande miljöbelastningen. Ny teknik för att uppnå de nya kraven finns i viss utsträckning, men kännedom och kunskap om dem saknas då de fått otillräcklig spridning. En del tekniska lösningar befinner sig fortfarande i en utvecklingsprocess och är inte färdigutvecklade för en större produktion. Ambitionen med denna nulägesanalys och därtill lika inventeringsarbete har varit att fånga in de lösningar och tester som gjorts och ta del av utvärderingarna så att vi kan dra nytta utav dessa i vårt arbete. Denna sammanställning grundar sig på muntlig information vi tagit del av under studiebesöken, ritningar, beskrivningar, protokoll samt rapporter vi samlat in.

    Syfte

    Syftet med vår resa till nedanstående objekt var att ta reda på hur flerfamiljshus med passivhus standard är byggda. Vilka stomval har gjorts och av vilken anledning. Vi ville också ta reda på hur man klarat av täthetskraven i de olika projekten samt hur detta mätts. I många fall verkar det som om utformning och arkitektur glöms bort när man ska bygga passivhus som om passivhuskravet vore så betungande att god utformning inte är förening med det. Därför ville vi också bedöma byggnaderna från arkitektoniska aspekter då dessa är av stor vikt för en bra miljö.

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    fulltext
  • 49. Jin, Yuan
    et al.
    Yan, Da
    Zhang, Xingxing
    Dalarna University, School of Information and Engineering, Energy Technology.
    An, Jingjing
    Han, Mengjie
    Dalarna University, School of Information and Engineering, Microdata Analysis.
    A data-driven model predictive control for lighting system based on historical occupancy in an office building: Methodology development2021In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 14, p. 219-235Article in journal (Refereed)
  • 50.
    Johansson, Daniel
    Dalarna University, School of Technology and Business Studies, Construction.
    Jämförelse mellan energiberäkning med TMF Energi och IDA ICE -fallstudie för ett småhus2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For each newly produced house, an energy calculation will be made in the production state and after the building has started to be used, a measurement will form the basis for the energy declaration. This is done to make demands on the energy consumption of the house, in order to reach the targets by 2020 and 2050. There are many different methods for calculating energy consumption. In this report, two energy calculation programs will be compared and look at how the energy usage responds to the solar radiation in the different methods. A hand calculation will be made to validate if the energy usage level is reasonable. The two programs are TMF Energy and IDA Indoor Climate and Energy (IDA ICE). The calculations are made on a standard house from the house supplier Fiskarhedenvillan. The method is based on having the same conditions and inputs in the different methods, so that the results can be compared and see how they differ from one another. The house will be placed differently to see how the orientation affects the energy consumption. The results for the simulations are close to each other and the hand calculation differs from the programs. Even if solar factors change in the different computer programs, results can be matched to form a pattern. The same patterns can be seen in the hand calculation, but with a greater deviation.

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