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  • 1.
    Al-Doori, Mustafa
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Synergisystem inom NCC2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis, a study has been carried out in conjunction with NCC Construction AB in Umeå. The study is about a working environment reporting system called Synergi. The purpose of this study is to make the system known and useful among staff who work with and for NCC, and to explore the problems and weaknesses that should be addressed. The goal of the study is to find improvement opportunities to facilitate system use. This helps the system to be useful, which in turn will reduce incidents by registering and systematizing all incidents, accidents and observations. The results of the interviews show, that in addition to the benefits, there are drawbacks and weaknesses in the system that should be addressed. Examples of these drawbacks and weaknesses are that the system is not known among NCC staff, and certain structural and functional problems. Once the case registration has been started, the cace can not be saved to be finished later. Some fields are unimportant or can be presented in a better way, and that access to cases that were reported are complicated. Suggestions for improvement recommendations are introductory lectures. They should be given until all staff begin to know and apply the system. In addition, structural and functional problems should be addressed, such as access to the cases that were reported will be easier to find by putting quick link to the home page. Status bar at the case registration is irrelevant. The field to the notification to the social insurance and AFA should be changed to a checklist choice, instead of the current form. It is also recommended that the case registration should be transfered to a person who will be responsible for Synergis case registreirng. It helps officials in the workplace to save time.

  • 2.
    Birkelöf, Lena Catharina
    Umeå University, Faculty of Social Sciences, Department of Economics.
    Exploring differences in expenditure for the functionally impaired: neighborhood interaction and the federal structure2010In: The annals of regional science, ISSN 0570-1864, E-ISSN 1432-0592, Vol. 44, no 1, p. 185-204Article in journal (Refereed)
    Abstract [en]

    The purpose of this paper is to study the determinants of the differences in expenditure on services for functionally impaired individuals among municipalities in Sweden. Expenditure per capita differs greatly across municipalities, even when accounting for the nature of the service. A spatial autoregressive model is used to test whether the decisions on the expenditure level in a neighboring municipality affect the municipality’s own expenditure. The results show that a positive spatial interaction exists among neighbors. However, when controlling for level differences among counties the spatial interaction coefficient becomes negative although not significantly determined. Therefore, the positive interaction first found can be interpreted either as a result of differences in the way county councils diagnose individuals or due to interaction or mimicking among the neighbors belonging to the same county council.

  • 3.
    Cheng, Xiaogang
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China; School of Electrical Engineering and Computer Science, Royal Institute of Technology, Stockholm, Sweden.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi'an, China.
    Liu, Guoqing
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    A total bounded variation approach to low visibility estimation on expressways2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 2, article id 392Article in journal (Refereed)
    Abstract [en]

    Low visibility on expressways caused by heavy fog and haze is a main reason for traffic accidents. Real-time estimation of atmospheric visibility is an effective way to reduce traffic accident rates. With the development of computer technology, estimating atmospheric visibility via computer vision becomes a research focus. However, the estimation accuracy should be enhanced since fog and haze are complex and time-varying. In this paper, a total bounded variation (TBV) approach to estimate low visibility (less than 300 m) is introduced. Surveillance images of fog and haze are processed as blurred images (pseudo-blurred images), while the surveillance images at selected road points on sunny days are handled as clear images, when considering fog and haze as noise superimposed on the clear images. By combining image spectrum and TBV, the features of foggy and hazy images can be extracted. The extraction results are compared with features of images on sunny days. Firstly, the low visibility surveillance images can be filtered out according to spectrum features of foggy and hazy images. For foggy and hazy images with visibility less than 300 m, the high-frequency coefficient ratio of Fourier (discrete cosine) transform is less than 20%, while the low-frequency coefficient ratio is between 100% and 120%. Secondly, the relationship between TBV and real visibility is established based on machine learning and piecewise stationary time series analysis. The established piecewise function can be used for visibility estimation. Finally, the visibility estimation approach proposed is validated based on real surveillance video data. The validation results are compared with the results of image contrast model. Besides, the big video data are collected from the Tongqi expressway, Jiangsu, China. A total of 1,782,000 frames were used and the relative errors of the approach proposed are less than 10%.

  • 4.
    Danielski, Itai
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande, Östersund.
    Nair, Gireesh
    The Department of Ecotechnology and Sustainable Building Engineering, Mid Sweden University, SE-831 25 Östersund, Sweden.
    Fröling, Morgan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande, Östersund.
    Heated atrium in multi-storey apartment buildings: a design for better energy efficiency and social interactions2013In: Passivhus Norden 2013: Papers and Posters, Lågan , 2013, p. 76-87Conference paper (Other academic)
    Abstract [en]

    The shape factor of a building expresses the ratio between the building’s thermal envelope area and its volume, or alternatively to its useful floor area. Buildings with lower shape factors will have lower heat losses through the thermal envelope and lower specific final energy demand. The shape factor of building could be reduced by a compact building shape design, and by increasing the volume of the building. However, the requirement for indoor natural light put a limit on the size of the building and therefore may limit the value of the shape factor. One possible solution to address this aspect is designing building with a heated atrium.

    An atrium is a large enclosed space within a building, and may have a glazed roof. In a multi-story apartment building an atrium has the potential to increase the social interaction between the residents and, with the right design, at the same time reduce the heating demand of the building due to lower building shape factor. However, the use of atrium in residential buildings in Nordic countries has not yet gained popularity.

    In this paper the impact of the heated atrium building with cylindrical shape design on the specific final energy is investigated by comparing such building design to conventional design buildings with similar floor area. The Nydalahuset project, in city Umeå in the north of Sweden, which is a multistory residential building with a heated atrium, is used as a case study to investigate the affect of the atrium on the social interaction among the building occupants.

    The results show that heated atrium building with cylindrical shape design is a better energy efficient design than the conventional buildings. Such buildings in cold climate could help to reduce the heat losses through the thermal envelope and facilitate to achieve the passive house criteria. Moreover, the Nydalahuset project suggests that the atrium design could improve the social interaction of occupants in residential buildings.

  • 5.
    Edvardsson, Berit
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Stenberg, Berndt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Bergdahl, Jan
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Eriksson, Nils
    Umeå University, Faculty of Social Sciences, Department of Sociology.
    Linden, G
    Widman, L
    The medical and social prognosis of Sick Building Syndrome: a follow-up study focusing on female patients2005In: Indoor air 2005: proceedings of the 10th international conference on indoor air quality and climate, vols 1-5 / [ed] Yang, X; Zhao, B; Zhao, R, Beijing: Tsinghua university press , 2005, p. 3706-3710Conference paper (Refereed)
    Abstract [en]

    A follow-up questionnaire focusing medical and social status, actions taken and personality traits was sent to 239 patients with Sick Building Syndrome (SBS) registered at the University Hospital in Umea, Sweden. The response rate was 79 percent. As females constituted 92 percent of the respondents all statistical analyses were restricted to women. Almost half of the respondents had been exposed to environments with visible water damages. Fatigue, irritated eyes and facial erythema were the most common symptoms. Nearly half of the patients claimed that the symptoms were more or less unchanged after 7 years or more. Twenty-five percent of the patients were on the sick-list and twenty percent drew disability pension due to SBS-symptoms at follow-up. Symptoms were often aggravated in different situations in everyday life. No important deviations concerning personality factors were found. The results support that early and comprehensive measures for rehabilitation are essential for these patients.

  • 6.
    Emil, Rönnmark
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energikartläggning av Kopparhuset i Skellefteå2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 7.
    Glas, Bo
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Stenberg, Berndt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Sunesson, Anna-Lena
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Comparison of three adsorbents for diffusive sampling of airborne volatile organic compounds in office environments2005In: Indoor air 2005: proceedings of the 10th international conference on indoor air quality and climate, vols 1-5 / [ed] Yang, X; Zhao, B; Zhao, R, Beijing: Tsinghua university press , 2005, p. 2713-2717Conference paper (Refereed)
    Abstract [en]

    Volatile organic compounds were personally sampled by people classified as cases (people having certain SBS symptoms) and controls, i.e. people not fulfilling the criteria's for cases. The aim of the study was to find out which adsorbent that gave the best separation between SBS cases and controls based on their chemical exposure of VOCs. The statistical method used was partial least squares discriminant analysis (PLS-DA). The adsorbents compared were Carbopack B, Chromosorb 106 and Tenax TA. The study included 30 office workers wearing diffusive samplers during one working week. The samplers were analysed with thermal desorption-GC-MS, and each chromatographic peak was included in the data evaluation. Tenax TA gave the best separation between cases and controls with a Q(2) = 0.434 and R(2)Y = 0.873 for three components. Analyses of samples taken with Carbopack B and Chromosorb 106 showed no ability to discriminate between the two classes.

  • 8.
    Gustavsson, Leif
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Implementering av energieffektiviseringsåtgärder i befintlig bebyggelse: Report prepared for the Swedish Energy Agency2010Report (Other (popular science, discussion, etc.))
    Abstract [en]

    There is great potential to improve energy efficiency in existing Swedish residential buildings. However, the successful implementation of efficiency measures depends on economical and technical factors, as well as on the attitudes and perceptions of the relevant actors. A better understanding of their attitudes and perceptions may influence the design of suitable policy measures that increase the adoption of energy efficiency measures. In this context, we conducted mail-in surveys completed by owners of detached houses, chairmen of co-operative housing associations (bostadsrättsförening) and municipality energy advisers in Sweden. We also interviewed window sellers/installers in Jämtland.

    Results show that it was important for the majority of homeowners to reduce their household energy use, with most undertaking no-cost measures (e.g., switching off lights). However, 70–90% of the responding homeowners had no intention of adopting building envelope measures over the next 10 years. The main reason for non-adoption was that homeowners were satisfied with the physical condition and thermal performance of their existing building envelope components. Homeowners who thought their energy cost was high were more likely to adopt an investment measure compared to those who thought their energy cost was low. Investment costs and annual energy cost savings were the most important factors in adoption of energy efficient building envelope measures. Therefore, economic incentives may induce homeowners to adopt energy efficiency investment measures. However, a large percentage (64%) of homeowners was unaware of the existence of government support for reducing household energy use. Information campaigns announcing the availability of economic incentives and the cost advantages of energy efficiency measures may be helpful in the adoption decision.

    Homeowners‘ considered interpersonal sources, builders, installers and energy advisers as important sources of information for their adoption of energy efficiency measures. Though a large percentage of respondents considered energy advisers as an important source of information, only 14% of homeowners had contacted an energy adviser in the past. Our findings suggest that the energy advice service is important for homeowners, but more efforts are needed to increase homeowners‘ awareness of and satisfaction with such services. The majority of municipal energy advisers were of the opinion that more training in technical aspects of energy issues and increased financial support could improve their performance.

    Installers and material suppliers are important actors in homeowners‘ adoption of energy efficiency measures. For example, approximately 53% of responding homeowners to a survey in Jämtland/Västernorrland stated that the window seller/installer from whom they had bought windows had recommended a particular type of window, and 97% had installed the windows that were recommended. The window sellers/installers in Jämtland prefer a window that is ―reasonably‖ energy efficient. They believe that windows with a U-value of 1.2 W/m2K are good and there is no reason to further improve the energy efficiency. The majority did not recommend windows with U-value <1.2 W/m2K. They were concerned about the condensation issues and high prices of such windows. This may influence the diffusion of very energy efficient windows in Swedish detached houses.

    About 80-95% of chairmen in co-operative housing associations who responded to our survey had no intention of adopting building envelope measures over the next 10 years. They were satisfied with the existing building envelope components, which may be one of the reasons for this lack of intention. As in the case of owners of detached houses, economic factors, like annual energy cost savings and investment costs, guide the implementation of energy efficiency investment measures in co-operative housing associations. However, about 66% of the responding chairmen did not consider financial constraint as a barrier to implementing investment intensive energy efficiency measures. For 54% of the respondents limited in-house competency to evaluate the benefits of energy efficiency measures was the main barrier.

    The majority of owners of detached houses (80%) and chairmen of co-operative housing associations (70%) perceived that economic policy instruments, such as investment subsidies and tax deductions, would encourage them to implement energy efficiency measures. Other policy instruments, especially information instruments, were perceived as less effective. Among various information policies, increasing the frequency of meter reading received the highest approval with 38% of homeowners, whereas approximately 41% of housing association chairmen thought that individual metering of heating and hot water use could be effective. Approximately 30% of homeowners and housing association chairmen thought that energy declaration was effective.

  • 9.
    Jansson, Madeleine
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Identifiering och sanering av byggmaterialet asbest2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Each year, the number of deaths caused by the cancerous substance asbestos increases, even though it was banned in Sweden in 1982. The risk of exposure from materials containing asbestos to the workers in the building trade continues to be high. The most exposed categories are demolition and repair workers. The amount of asbestos still remaining in Swedish buildings is estimated to be around 400 000 tons, which continues to put the construction workers at risk. In addition to the remaining asbestos, there is an ongoing generational renewal in the building trade. The older generation with experience and knowledge on the substance is being replaced with a new and enthusiastic generation whose knowledge on dangerous substance of asbestos is lacking.

     

    Sweden was the first country in the world to ban asbestos. At present, there are laws and regulations on how asbestos should be correctly handled and disposed of. To be able decontaminate buildings of asbestos commercially, the personnel must have completed specific educational programs. An asbestos decontamination consist of several advanced stages and is a time consuming process. There are strict demands on equipment, barriers and waste management in order to avoid exposure to asbestos. The dispersal of asbestos dust would affect surrounding categories of workers.

     

    Despite the laws and regulations, there are still inadequacies in the handling of asbestos. To investigate the scope of the deficiencies, current asbestos decontamination procedures at Läroverket 1 in Umeå will be observed and compared to the theoretical decontamination procedure.

     

    The decontamination procedure performed at Läroverket 1 was meticulously and correctly performed according to the theory. It required extensive equipment, knowledge and carefulness to avoid dispersing asbestos dust to surrounding areas and personnel categories. No deficiencies of note could be identified during the decontamination procedure, but there are other other parts of the asbestos handling which could be improved. The investigations which were undertaken to prove the existence of asbestos were insufficient. Places which contained asbestos were missed altogether, and places which were deemed to not contain asbestos during testing were subsequently found to contain asbestos. This is a large deficiency which can not be allowed, since the investigation before decontamination is crucial to ensure that no workers are exposed to asbestos during construction. The methods used for decontamination are obsolete, which is true for large parts of Sweden. In comparison to e.g. UK, where research efforts have resulted in better decontamination procedures, the levels of exposure to asbestos dust are significantly higher in Sweden. The choice of decontamination method is something that needs to be seriously considered in order to improve the working environment for decontamination crews and other personnel categories.

     

    The personnel performed the decontamination according to applicable Swedish law and regulation, but the investigations performed to determine areas containing asbestos and choice of decontamination methods are inadequate. To remedy this, higher demands must be placed on the safe working environment of the personnel. 

  • 10.
    Lindgren, Emil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Studie om BREEAM, Miljöbyggnad, Svanenmärkning och GreenBuildning2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This essay will examine four different certifications regarding environmental aspects in the building industry in the Swedish context. The bachelor essay has been made in collaboration with MAF Arkitektkontor AB. The company is active within building technique, interior design and projection. The aim of this essay is to educate the reader about Greenbuilding, Miljöbyggnad, BREEAM and Svanen. The methods of survey for each certification system will be explained more in detail. The process of certification, the costs and the different grading systems are some of the factors that will influence the choice of certification system. The results will be based on the theory of the different certification systems. There are considerable differences between each system. The extent and the demands of each system are some aspects that have been taken into consideration. BREEAM and Svanenmärkning are two comprehensive systems that require high demands on all levels in the building process. In the planning phase there are a lot of demands that need to be fulfilled in order to achieve the goal of certification. A technique well adapted makes it easier for the architect to create good possibilities for the future building. To achieve a certificated building there are a lot for tools to simplify the works of those involved in the project. BIM is one of the tools that can be to a huge advantage within the building industry. ArchiCAD from Graphisoft is the program used by MAF. The broadness of the program makes it possible to achieve a lot of the demands. In several of the systems the materials chosen are essential and, thus need to be documented from start. There are different material data bases available on the market that help to choose the right material for each building.

  • 11.
    Lindqvist Franklin, Carl
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Klimatkalkyl av bjälklag2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is written as the concluding part of the program Bachelor of Science in Building Engineering.

     

    The report details the climate impact of three different types of floor structures in the form of carbon dioxide. A concrete slab, a light weight floor structure and a timber floor cassette. The floor structures build-up and the various constituent materials are studied and then designed with the goal to provide as low of a carbon footprint as possible. The climate impact is calculated based only on the production and extraction of the materials to the respective floors.

     

    A central part of this work was to study how the climate impact of a concrete slab changes depending on the thickness of the slab. This due to how the reinforcement relates to the slab thickness. The calculations show that the concrete slabs should be designed as thin as possible to provide the lowest carbon footprint. Finally the calculated climate impact of each floor structure is compared to each other, which shows that the light weight floor structure has the lowest impact on the environment.

     

    The construction industry are most of the time focused on being as effective as possible and do things as always done. This means that new methods of construction are only rarely realized.

     

    Altogether the three floor structures have different advantages and disadvantages. The conclusion from the work is that with more studies that compare various materials, as well as actual results from buildings where new methods proves profitable while sustainable for the future the construction industry will change.

  • 12.
    Lodmark, Manne
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effekter av nära-nollenergikravet för projektering av flerbostadshus2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to steer development towards more energy efficient buildings, the EU parliament have ruled that all buildings produced after the 1st of January 2021 should be classified as near-zero energy houses. This objective is expected to come as stricter energy performance requirements in 2020, and the companies that design the buildings are now facing a change. This study has been made on behalf of Sweco Architects AB in Umeå with the purpose to evaluate what the effects of the EU directive has on one of their designed multi-family houses. Furthermore, the purpose is to give a broader view on what effects the coming energy performance regulations have on other multi-family houses in Umeå. The aim of the report is to obtain a primary energy number, calculated with regard to the forthcoming changes, as well as to study how much a multi-family house’s primary energy number is affected by the forthcoming energy requirements. Furthermore, the aim is to investigate how the primary energy number is affected by the regulations regarding sources heat production of buildings. A reference building is calculated in the energy calculating software BV2 in order to compare energy use and average heat transfer coefficient to the current as well as the future energy performance requirements for near-zero energy houses. After that, studies are made to see how the primary energy number is affected by the changes taking effect 2020. After calculations in BV2 , a primary energy number of 71.7 kWh/m2 per year was established along with an average heat transfer coefficient of 0.288 W/m2K. These pass and fulfill the current as well as the forthcoming requirement levels, and therefore the reference building is well put-up against the regulations that take effect in 2020. Several simulations of a multi-family house with a primary energy number of 85 kWh/m2 per year were calculated on the basis of future values for primary energy factor and geographical adjustment factor. In all cases the primary energy number decreased with about 12 %. As the forthcoming requirement level reduces with about 9 %, it could be concluded that if a multi-family house in Umeå with central heating fulfills the current regulations, it will fulfill the forthcoming ones as well. However, the regulations will be tougher for electricity-heated buildings followed by buildings that obtain their heating from biofuels, gas or oil.

  • 13.
    Mahapatra, Krushna
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Energy advice service as a policy instrument to promote energy efficiency in residential sector: perception of end-users and service providers2011In: SB11, World Sustainable Building Conference, Helsinki, Finland. October 18-21, 2011, 2011Conference paper (Refereed)
  • 14.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Östersund.
    Mahapatra, Krushna
    Mittuniversitetet, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Östersund.
    Adoption of energy efficiency measures in Swedish detatched houses2009In: International Scientific Conference on Energy systems with IT,  March 11-12, in connection with 'Energitiget 2009', Stockholm, Sweden, 2009Conference paper (Refereed)
    Abstract [en]

    The paper focuses on Swedish homeowners’ need for and perceptions about adopting building envelop energy efficiency measures such as improved windows and attic and wall insulation. The results of a questionnaire surveying 3000 randomly selected homeowners during the summer of 2008 revealed that about 70-90% of the respondents had no intention of implementing such a measure over the next 10 years. The main reasons for non-adoption were that homeowners were satisfied with the physical condition, thermal performance, and aesthetics of their existing installations. A greater proportion of respondents perceived that improving attic insulation has more advantages than other measures, but windows were more likely to be installed than attic insulation was to be improved. Respondents gave high priority to economic factors in deciding on an energy efficiency measure, while environmental aspects were given lower priority. Hence, economic incentives could be useful in promoting the adoption of building envelope energy efficiency measures. Interpersonal sources, construction companies/installers, and energy advisers were important sources of information for homeowners as they planned to install energy efficiency measures.

  • 15.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Mahapatra, Krushna
    Linnéuniversitetet, Växjö.
    Gustavsson, Leif
    Linnéuniversitetet, Växjö.
    Implementation of energy efficient windows in Swedish single-family houses2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 89, no 1, p. 329-338Article in journal (Refereed)
    Abstract [en]

    A questionnaire survey of 1010 homeowners in Jämtland and Västernorrland, which are two counties in central Sweden, was conducted to understand the factors influencing their decision to install energy-efficient windows. We complemented this survey with an interview of 12 window sellers/installers in the county Jämtland. The annual energy cost reduction, age, and condition of the windows were the most important reasons for the window replacement decision. Approximately 80% of the respondents replaced their windows with energy-efficient windows with U-value of 1.2 W/m2 K. Condensation problems, perceived higher prices, and lack of awareness about windows with lower U-values were important reasons for non-adoption of more energy-efficient windows. Window sellers/installers have a strong influence on homeowners’ window selection that was indicated by the 97% of homeowners who bought the windows that were recommended to them. Sellers/installers revealed that they did not recommend windows with U-value of less than 1.2 W/m2 K because they thought that investing in such windows was not economical and because windows with U-value less than 1.2 W/m2 K could cause water condensation on the external surface of window pane.

  • 16.
    Ohlsson, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ekblad, Alf
    Örebro universitet.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nyström, Robin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Stable carbon isotope labelled carbon dioxide as tracer gas for air change rate measurement in a ventilated single zone2017In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 115, p. 173-181Article in journal (Refereed)
    Abstract [en]

    Carbon dioxide (CO2) has often been used as tracer gas for measurement of the air change rate l (h1 ) in buildings. In such measurements, a correction is required for the presence of indoor CO2, which commonly consists of atmospheric CO2 mixed with human respired CO2. Here, 13C isotope-labelled CO2 was employed as tracer gas, and cavity ring-down spectroscopy (CRDS) was used for simultaneous measurement of the two isotope analogues 12CO2 and 13CO2. This enabled the simultaneous measurement of the 13CO2 tracer gas, with correction for background 13CO2, and the concentration of indoor CO2, allowing for presence of occupants. The background correction procedure assumes that the isotope delta of the background indoor CO2 equals dB ¼ 19‰, based on the prior information that the carbon isotope ratio RB ¼ 13C/12C of all carbon in the bio-geosphere of earth is in the interval 0.010900 < RB < 0.011237. Evidence supported that l could be accurately measured, using the new 13CO2 tracer method, even when the background 13CO2 concentration varied during the measurement time interval, or when the actual dB value differed from the assumed value. The measurement uncertainty for l was estimated at 3%. Uncertainty in l due to uncertainty in RB, uRB(l), was estimated to increase with a decreasing amount of 13CO2 tracer. This indicated that at least 4 ppm tracer must be used, in order to obtain uRB(l)/l < 2%. The temporal resolution of the l measurement was 1.25/l h.

  • 17.
    Pettersson, Patrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Dimensionering och studie av stommar i limträ, stål och betong med avseende på kostnad och miljöpåverkan2014Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis includes a project whose purpose is to design alternative frameworks in steel andconcrete of an existing barn in glulam. These options were then compared in terms of costand environmental impact.The author argues that today there are several different options for frameworks, in terms ofboth materials and design, and it can make the choice of framework difficult. The work is notintended to determine which material is best, but rather to present the differences betweenthe materials. Then it's up to the person who reads to determine if one finds anenvironmental efficient material best or if you favor less cost.In the report's results section the results from all the alternative designs are presented, whichhas later been used to compare the frames. Environmental impacts were established using alifecycle assessment, where Tyréns AB has developed a set of rules for structures. The projectwas delimited to only generate environmental impact outcomes in terms of carbon dioxideemissions from fossil fuel use and the cost to the material without regard to the attachments.The result for the price was done by contacting different suppliers of each material.The results from the project indicate that framework with tension rods are more favorableamong the options put forward in this report. Of the alternatives, it was found that theconcrete and glulam were fairly similar with regard to material cost and that glulam was mostsuitable in terms of environmental impact during production.

  • 18. Ramírez-Villegas, Ricardo
    et al.
    Eriksson, Ola
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Life Cycle Assessment of Building Renovation Measures – Trade-off between Building Materials and Energy2019In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 3, article id 344Article in journal (Refereed)
    Abstract [en]

    The scope of this study is to assess how different energy efficient renovation strategies affect the environmental impacts of a multi-family house in a Nordic climate within district heating systems. The European Union has set ambitious targets to reduce energy use and greenhouse gas emissions by the year 2030. There is special attention on reducing the life cycle emissions in the buildings sector. However, the focus has often been on new buildings, although existing buildings represent great potential within the building stock in Europe. In this study, four different renovation scenarios were analyzed with the commercially available life cycle assessment software that follows the European Committee for Standardization (CEN) standard. This study covers all life cycle steps from the cradle to the grave for a residential building in Borlänge, Sweden, where renewable energy dominates. The four scenarios included reduced indoor temperature, improved thermal properties of building material components and heat recovery for the ventilation system. One finding is that changing installations gives an environmental impact comparable to renovations that include both ventilation and building facilities. In addition, the life cycle steps that have the greatest environmental impact in all scenarios are the operational energy use and the building and installation processes. Renovation measures had a major impact on energy use due to the cold climate and low solar irradiation in the heating season. An interesting aspect, however, is that the building materials and the construction processes gave a significant amount of environmental impact.

  • 19.
    Rocha, Luis E C
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Structural evolution of the Brazilian airport network2009In: Journal of Statistical Mechanics: Theory and Experiment, ISSN 1742-5468, E-ISSN 1742-5468, p. 04020-Article in journal (Refereed)
    Abstract [en]

    The aviation sector is profitable, but sensitive to economic fluctuations, geopolitical constraints and governmental regulations. As for other means of transportation, the relation between origin and destination results in a complex map of routes, which can be complemented with information associated with the routes themselves, for instance, frequency, traffic load and distance. The theory of networks provides a natural framework for investigating the dynamics on the resulting structure. Here, we investigate the structure and evolution of the Brazilian airport network (BAN) as regards several quantities: routes, connections, passengers and cargo. Some structural features are in accordance with previous results for other airport networks. The analysis of the evolution of the BAN shows that its structure is dynamic, with changes in the relative relevance of some airports and routes. The results indicate that the connections converge to specific routes. The network shrinks at the route level but grows in number of passengers and amount of cargo, which more than doubled during the period studied.

  • 20. Ruud, Svein
    et al.
    Östman, Leif
    Orädd, Philip
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy savings for a wood based modular pre-fabricated facade refurbishment system compared to other measures2016In: Sustainable built environment Tallinn and Helsinki Conference SBE16: build green and renovate deep, 2016, p. 768-778Conference paper (Refereed)
    Abstract [en]

    There is a need to focus on energy efficiency for the existing buildings, especially buildings erected before the energy crises in the seventies, as these buildings provide a massive potential for improvements in energy performance. The facades of these buildings are also facing an increased need for a face-lift. There are a large number of such facades in all these countries. One problem is that these buildings must be refurbished at low costs and with limited disturbance to the users/tenants. In this study we have investigated the energy efficiency of a modular pre-fabricated facade refurbishment system based on wood and compared it to two existing systems for on-site mounting of additional insulation. These existing alternatives require a lot of on-site works. Hence prefabricated solutions would, of course, offer advantages. There have been several attempts to develop such solutions in recent years but so far none of them have provided an acceptable solution. This approach is based on an alternative with small scale prefab elements with a simple assembly process. The energy analyses concentrate on thermal bridges and U-values, relating it to the total energy performance and compared to the current situation and comparable refurbishment methods. We have mainly focused on the wall structures but as a comparison also other energy saving measures has been investigated shortly. For the very common reference building the pre-fabricated solution is the third most effective energy measure. We have also conducted a study of the energy efficiency regulations in different Nordic countries in order to see what the current legal framework is, and tried to sort out how far it is possible to improve energy efficiency by means of improving the U-value of the exterior walls. The outcome is a verification of the energy efficiency of the chosen prefab structure as a solution for refurbishment. The advantages are to be found in the dry production process combined with a simple and fast assembly on site. Similarly, there are advantages in the reduced number of thermal bridges and in the potential for the use of recyclable materials. Another advantage is that it has an integrated air tightness that is mounted on the outside of the existing wall. This is part of a larger research project aiming at cost efficient and sustainable solutions for refurbishment of facades in a Nordic context. In the larger research project, we have also conducted a cost-benefit analyses and studied moisture conditions in order to see how far this solution might be feasible. The ultimate aim is to test a product and compare the findings from demo projects in the three countries Norway, Sweden and Finland.

  • 21.
    Ström, Kristina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Livscykelanalysen som metod mot ökad miljöhänsyn och hushållning av energi och material: En fallstudie med utvärdering av verktyg anpassade för LCA på byggnader2014Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    The method of analyzing environmental impacts and resource use from a lifecycle perspective is growing in popularity as a method giving the opportunity to lessen negative impact on the environment and depletion of natural resources through comparative analysis. The report focuses on comparing tools available for lifecycle analysis of buildings and building materials as well as the method of LCA in general. A field study is made through analyzing a building with the aid of LCA and according to ISO 14040, and this brings further clarity as to how the method is used. The results show advantages and disadvantages of current LCA tools for buildings as well as pros and cons of the method of LCA itself. The results of the field study indicate the risk that LCA can be used and interpreted subjectively as well as the risk of setting too low data quality. Results also highlight the absence of some important features linked to environmental concern and sustainable resource management. However, if LCA is used in an objective and scientific manner it might be a key to using proper resource management in terms of lessening negative impacts on the environment and depletion of natural resources and some suggstions are made as to how to change the standards of the method.

  • 22.
    Vesterberg, Jimmy
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Andersson, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Achieved Energy and Climate Goals in Project Ålidhem: An Evaluation of a Refurbishment of 21 Swedish multifamily Buildings2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 132, p. 51-56Article in journal (Refereed)
    Abstract [en]

    In Umeå, situated in the north part of Sweden, the largest refurbishment project undertaken by the public housing company in Umeå was completed in 2014. The project had ambitious goals to decrease the bought energy use for domestic hot water, building electricity and space heating, by 50 %. In order to achieve this, a variety of energy conservation measures were implemented in 21 multifamily buildings during the four-year project. This paper describes the used evaluation approaches and the achieved energy and climate goals. Finally, it offers some reflections that are hoped to be useful in similar projects. 

  • 23.
    Westberg, Johanna
    et al.
    Umeå University.
    Holmström, Lars
    Akademiska hus Region Norr.
    Redin, Lisa
    Umeå University.
    Rebuilding and a conscious and courageous leadership reduced energy consumption more than 80 percent2014In: Sustainable Buildings. Results: Conference proceedings. Volume 6, Madrid: GBCE , 2014Conference paper (Refereed)
    Abstract [en]

    Akademiska Hus AB has the ambition to halve the energy cost from the year 2000 to 2025. Between 2006 and 2010 the Natural Science Building was renovated completely, and a new presence- and pressure controlled air treatment system was installed. The results show that the investments reduced the heat energy consumption with about 80 percent and the building electricity consumption with about 85 percent. Akademiska Hus AB Region North, had in 2010 built the most energy efficient office building in the region, and still the building is one of the most energy efficient buildings in Umeå. The conclusion of the project is that it is possible with quite easy and also viable investments build more energy efficient than the building Code and the building industry in common requires. A strategic work, ambitious objectives and a conscious and courageous leadership seems to be just as important.

1 - 23 of 23
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