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  • 51.
    Mahapatra, Krushna
    et al.
    Mid Sweden University, Östersund, Sweden.
    Nair, Gireesh
    Mid Sweden University, Östersund, Sweden.
    Gustavsson, Leif
    Mid Sweden University, Östersund, Sweden ; Linnaeus University, Växjö, Sweden.
    Energy advice service as perceived by Swedish homeowners2011Inngår i: International Journal of Consumer Studies, ISSN 1470-6423, E-ISSN 1470-6431, Vol. 35, nr 1, s. 104-111Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    External actors can influence potential adopters to adopt energy efficiency measures. In Sweden municipality energy advisers are one such actor group who provides energy advice and information to the end users. The success of energy advice service for improvement of energy efficiency of detached houses depends on homeowners' perception towards it. In this context, we conducted a national survey of about 3000 owners of detached houses through stratified random sampling method in the summer of 2008. We found that majority of owners of detached houses consider energy advisers as an important source of information. Furthermore, many homeowners who contacted energy advisers for advice had implemented the suggestions. However, only a few homeowners had contacted an energy adviser. Our findings suggest that it is beneficial to continue the energy advice service, but more efforts are needed to increase homeowners' awareness of and satisfaction with such services.

  • 52.
    Mahapatra, Krushna
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Perceptional and soicio-economic factors in adoption of low energy houses2009Inngår i: International Scientific Conference on Energy systems with IT, March 11-12, in connection with 'Energitiget 2009', Stockholm, Sweden., 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Diffusion of low energy houses reduces greenhouse emission from residential sector. However, adoption of such houses depends on the perception of the potential buyers. In this paper we have analyzed Swedish homeowners’ perception of low energy houses. Data was collected in 2008 from a mail-in questionnaire survey of about 3000 owners of detached houses. Results showed that about 39% of respondents, especially young, educated or whose household income was high, would consider buying a low energy house. Majority of the respondents agreed that a low energy house in comparison to a conventional house has lower operating energy cost, but higher investment cost. Majority thought that low energy houses do not have lower resale value, lower aesthetic appearance, or greater operational difficulty.

  • 53.
    Mahapatra, Krushna
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Policy instruments to promote energy efficiency in the building sector: Indian and Swedish experiences2008Inngår i: 14th Annual International Sustainable Development Research Conference, 2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Energy efficiency measures in buildings are widely regarded as cost effective options to mitigate climate change. However, policy instruments are needed to improve the diffusion of such measures. The policy mix may be country-specific. Here, we compare and contrast the various policy instruments designed to enhance energy efficiency in the building sector in India and Sweden. The objective is to explore if the experiences of Sweden that have promoted energy efficiency in buildings for decades could be useful for India, where energy demand is forecasted to strongly increase. India and Sweden are very different, for example, in terms of development, size, priorities, population, and climatic conditions. In Sweden, policy initiatives to reduce energy use in buildings date back to the 1970s and the government is committed to significantly reduce energy use in buildings. In India, the interest in energy efficiency improvements in buildings is a recent phenomenon. The country introduced an energy conservation building code in 2007. This analysis shows that policy instruments are more prevalent in Sweden than in India where regulatory instruments are particularly lacking. Hence, Swedish buildings are more energy efficient than those in India. The Swedish experience could be useful for devising programs and implementing policy instruments to improve energy efficiency of Indian buildings.

  • 54.
    Mahapatra, Krushna
    et al.
    Ecotechnology, Mid Sweden University, SE-83125 Östersund, Sweden.
    Nair, Gireesh
    Ecotechnology, Mid Sweden University, SE-83125 Östersund, Sweden.
    Gustavsson, Leif
    Ecotechnology, Mid Sweden University, Östersund, Sweden and Linnaeus University, Växjö, Sweden.
    Swedish energy advisers' perceptions regarding and suggestions for fulfilling homeowner expectations2011Inngår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 39, nr 7, Special Issue, s. 4264-4273Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Municipality energy advice services were re-introduced in Sweden in 1998 as a way of advising end-users, mainly owners of detached houses, on energy issues. In this paper, we investigate Swedish energy advisers' perceptions of homeowners' awareness of the energy advice service and their perceived ability to fulfil homeowners' expectations. Our study is based on a mail-in questionnaire survey conducted in 2009 and distributed to municipality energy advisers in all municipalities in Sweden. About 66% of the energy advisers responded. The results show that 43% of the energy advisers thought that fewer than 50% of the homeowners were aware of the service and that mass media advertisements and presentations at different organisations could improve homeowner awareness. Energy adviser attitudes, job satisfaction, and the perception that the advisers possessed up-to-date and good knowledge and sufficient financial resources to execute their duties had a significant influence on their perceived ability to fulfil homeowner expectations. Increased training in technical aspects of energy measures and increased financial support were the two measures most widely suggested as a means to improve energy advisers' performance.

  • 55.
    Mahapatra, Krushna
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    The role of energy advisers on adoption of energy measures in detached houses2009Inngår i: International Scientific Conference on Energy systems with IT,  11-12 March, in connection with the ‘Energitinget 2009’, Stockholm, Sweden, 2009Konferansepaper (Fagfellevurdert)
  • 56.
    Melin, Mikael
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Konserveringsmetoder mot korrosion på vattensidan av hetvatten pannor: Preservation methods against corrosion at the waterside of hot water boilers2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Rapporten redovisar en utredning av konserveringsmetoder för vattensidan under stilleståndsperioder av ett värmeverk bestående av fem hetvattenpannor med ett gemensamt ångnät. Syftet var att utvärdera olika metoder för att motverka korrosion då pannorna inte är i drift. Konserveringsmetoderna som utreddes och jämfördes internt var konservering med en kvävgaskudde, ångkudde, torrläggning och en kemisk lösning. Att utreda metoderna innebar att uppskatta dess kostnad ekonomiskt genom att beräkna en årskostnad. För att besvara hur effektivt deras skydd mot korrosion är användes litteraturens referenser och teoretiska samband för att uppskatta syrehalten i matarvattnet. För att kunna göra en realistisk jämförelse mellan metoderna har den avgivna effekten för värmeverkets pannor under driftåret 2016 använts som en grund för beräkningarna. Årskostnaderna från konserveringsmetoderna är från 2016 års driftdata av värmeverket. En kvävgaskudde med en renhet av 99,999 % kan resultera i en syrehalt av 9,6 ppb för matarvattnet och har en total årskostnad av 77 300 SEK. En ångkudde har potentialen att bevara vattnet i princip syrefritt och har en total årskostnad av 809 000 SEK med en extern elpanna för ångproduktion. Att torrlägga pannorna är bara möjligt under vissa perioder av året dock skulle en total årskostnad av eldriften för att hålla pannorna torra motsvara en kostnad av 17 500 SEK. Metoden med en kemisk lösning hade en totalårskostnad av 1 640 000 SEK. Baserat på tillgänglig information och utförda antaganden är slutsatsen att värmeverket ifråga rekommenderas att upphöra med en kemisk konserveringsmetod och övergå till en kvävgaskudde som konserveringsmetod mot korrosion då pannorna inte är i drift.

  • 57. Moilanen, Antero
    et al.
    Lehtinen, Jere
    Kurkela, Minna
    Muhola, Mirja
    Tuomi, Sanna
    Carlsson, Per
    Öhman, Marcus
    Güell, Berta Matas
    Sandquist, Judit
    Lundgren, Joakim
    Andersson, Jim
    Umeki, Kentaro
    Ma, Charlie
    Kurkela, Esa
    Wiinikka, Henrik
    Wang, Liang
    Backman, Rainer
    Biomass gasification fundamentals to support the development of BTL in forest industry2015Rapport (Annet vitenskapelig)
  • 58.
    Mähler, Viktor
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Förstudie för en vindkraftpark på Malmölandet i Norrköping: En undersökning av förutsättningarna för en vindkraftpark på ett sen tidigare planerat område2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This is a feasibility study that examines various aspects of building a wind farm on Malmön in Norrköping. The feasibility study deals with interests of conflict, park design, electrical connections, production calculation, financial calculations and operating- and timetable.

    The report is divided into two distinct parts. First a theoretical part, which deals with conflicting interests, park design and electrical connections. Second a part with simulations dealing with production calculations, and financial calculations.

    Opposing interests are mapped so that problem areas can be found, and help put focus on the right places at a future environmental impact assessment (EIA). There are a number of areas where planners have to assess on an EIA, this thesis point on the most important areas. There are a few areas of national interest and the Natura 2000 protection. Part of the area of the planned park is also within Norrköping Airport area of influence and an assessment must be made by the civil aviation authority (CAA) to determine if a wind farm on the location would affect the air traffic and if so, what part of the location would be affected. Furthermore, there is the area of a flight route for birds as well as an area that is a common livelihood for birds. These should be examined to see if wind power in the area can become a problem for these birds.

    A production calculation has been implemented in the program WindPRO. This feasibility study has dealt with three different park designs with the wind turbine, Vestas V-126 3.3MW, which is the largest low wind turbine we found. Based on wind data, data for wind turbines, distance between turbines and other data we can do a calculation of how much energy the wind farm produces annually. Calculations were also made In WindPRO regarding sound levels and shadow creation. This is so that the wind farm will be designed so target values for noise and shadows are met. All park designs in this project has been designed so that the sound and shadow benchmarks for buildings nearby are met.

    Based on production estimates, an economic calculation been carried out. The different park designs have between 7 and 11 wind turbines with an annual energy production of between 58 and 91 GWh per year. The wind turbines have been estimated to cost approximately 25 Mkr each, plus about 10 % of turbine cost for foundations, roads, power lines and other similar expenses. One calculation was made for the case the electric connection could be done directly to some of the industries in the location, for this simulation the cost over the wind mill was about 15 %. Under all these conditions, the project should be financially sustainable, with a payback period of about 6-11 years and a return of investment of 1-7 %.

  • 59.
    Mäkelä, Mikko
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Division of Biomass Technology and Chemistry, SE- 90183 Umeå, Sweden.
    Edler, Jenny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Geladi, Paul
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Low-temperature drying of industrial biosludge with simulated secondary heat2017Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 116, s. 792-798Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Drying is an energy-intensive unit operation and future sludge dryers should be able to take advantage of the secondary energy of industrial environments. This work reports the use of a pilot cyclone for drying biosludge at low temperatures and simulating the use of secondary waste heat. The pilot-scale experiments were performed according to an experimental design and the results interpreted using principal components and multiple linear regression. The dry solids content of processed sludge increased from 9 to 19-68% during the experiments with a predicted energy consumption of <1.7 kWh kri H2O. However, the combined energy consumption was 80-230% higher indicating that the efficiency of sludge drying was governed by the availability of secondary heat. Drying sludge to solid contents sustainable for fossil fuel replacement at pulp and paper mills could be performed with secondary heat at a temperature of 70 degrees C, a pilot-scale feeding capacity of 170 kg h(-1) and a corresponding energy consumption of 1.0 kWh kg(-1) H2O. The results suggest that the use cyclones could be an efficient option for future sludge drying at pulp and paper mills.

  • 60.
    Nair, Gireesh
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande, Östersund.
    Fostering community based social marketing for energy efficiency improvements in the residential sector2013Inngår i: International Conference on Applied Energy 2013, 2013Konferansepaper (Fagfellevurdert)
  • 61.
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Implementation of energy efficiency measures in Swedish single-family houses2012Annet (Annet vitenskapelig)
  • 62.
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Waste minimization circle in aluminium utensil manufacturing units2002Annet (Annet (populærvitenskap, debatt, mm))
  • 63.
    Nair, Gireesh
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Allard, Ingrid
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Åstrand, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Building professionals' views on energy efficiency compliance requirements2017Inngår i: 11th Nordic Symposium on Building Physics, NSB 2017 / [ed] Geving S., Time B., Elsevier, 2017, Vol. 132, s. 988-993Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In Sweden, the national building code (BBR) stipulates the specific energy use as an indicator to verify whether a newbuilding is complying with its design-phase energy performance values. However, previous studies have shown that there may belarge differences between the calculated specific energy and the actual monitored energy use. The differences are attributed tovarious reasons including the actual energy behaviour of the occupants as compared to the standard values used in thesimulations. This may lead to disputes between the client and the contractor on the responsibility of meeting the energyrequirements.In this study an adapted version of Delphi methodology was used to understand the building professionals’ view on variousindicators used to verify building energy performance. The study showed that professionals are concerned with the use of specificenergy as an indicator in the building procurement process as they do not have control over the occupants’ energy behaviour.Majority of the professionals expressed a large confidence in the average U-value of the building, component U-values and thespecific heat loss figure by the Swedish center for zero-energy buildings as indicators of building energy performance.

  • 64.
    Nair, Gireesh
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Azizi, Shoaib
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    A management perspective on energy efficient renovations in Swedish multi-family buildings2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 132, s. 994-999Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sweden has around 2.5 million dwellings in multi-family buildings, which constitute about 55% of the total dwelling units. The multi-family building ownership in Sweden can be categorized into municipal, private and co-operative ownership. Approximately 40% of apartments in multi-family buildings belong to municipal housing companies, while the rest is equally shared by private companies and co-operative housing associations. These organizations have different priorities, limitations and concerns related to energy renovations. Accordingly, in this sector the decisions to invest in energy efficiency improvement depends to a large extent on the type of ownership.

    In this study we analyzed the perspectives of different types of building ownership on energy efficient renovation. The analysis is based on detailed interviews of 4 senior managers representing the multi-family buildings under different ownership categories. Along with this we also interviewed a municipality energy adviser. All the interviewees are based in in North Sweden. The drivers to facilitate the rate of adoption of energy renovation in such buildings are discussed.

  • 65.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Carlman, Inga
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Organizational perspectives on adoption of energy efficiency measures in Swedish multi-storey apartment buildings2012Inngår i: MILEN International Conference, 22-23 November, Oslo., 2012Konferansepaper (Annet vitenskapelig)
  • 66.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling. Östersund.
    Diddi, Saurabh
    Bureau of Energy Efficiency, New Delhi, India .
    Partial risk guarantee fund for ESCO business: an innovative support system for energy efficiency business2012Inngår i: ECEEE Summer study, European Council for an Energy Efficient Economy (ECEEE), 2012Konferansepaper (Fagfellevurdert)
  • 67.
    Nair, Gireesh
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Eklund, Erik
    “Energy visualization” as a tool to influence the energy use in a municipality kitchen2019Inngår i: eceee 2019 Summer Study on energy efficiency: Is efficient sufficient?, 3–8 June, Presqu’île de Giens, Hyères, France, European Council for an Energy Efficient Economy (ECEEE), 2019, s. 13-18Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In Sweden, municipalities’ own and operate the kitchens that cook food for pre-schools, schools and the elderly care facilities. There are 68 kitchens in the municipality of Umeå and providing feedback to the kitchen staff on energy use could facilitate them to reduce the energy use in these facilities. Accordingly, an “energy visualization” project was initiated in one of the kitchen: Nordstjärnan, which is a newly built kitchen equipped with separate meters for appliances that continuously record the energy use.

    For the “energy visualization” project, a visualization design software called “Siemens Control Point” is used. The software is integrated with the existing steering and control system and connected to almost all sensors/meters in the building.The electricity use data from the kitchen was collected for 5 months prior to installation of the “energy visualization” project to establish a base line for the energy use. The average electricity use is referred in this paper as “Electricity budget”, which is calculated for each kitchen appliance that has an electricity meter.

    A trial was started in the kitchen from December 2018 onwards, wherein a display unit was designed to project the electricity use of the kitchen. The display unit, which is a large television screen, has different “slides”. For example, one of the slide is modelled to energy labelling. The energy labelling in the display has a rating from A+++ to D, which is calculated continuously based on the daily electricity use and the electricity budget. If the kitchen uses more electricity than budgeted then the rating will drop, and if the electricity use is less than the budget then the rating will increase. Furthermore, depending upon the energy performance of the kitchen the visualization screens also display “smileys” which are used as injunctive norms.

  • 68.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Barriers to implement energy efficiency investment measures in Swedish co-operative apartment buildings2011Inngår i: World Renewable Energy Congress 2011, Linköping, Sweden, May 8-11, 2011Konferansepaper (Fagfellevurdert)
  • 69. Nair, Gireesh
    et al.
    Gustavsson, Leif
    Mahapatra, Krushna
    Factors influencing energy efficiency investments in existing Swedish residential buildings2010Inngår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 38, nr 6, s. 2956-2963Artikkel i tidsskrift (Fagfellevurdert)
  • 70. Nair, Gireesh
    et al.
    Gustavsson, Leif
    Mahapatra, Krushna
    Owners perception on the adoption of building envelope energy efficiency measures in Swedish detached houses2010Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, nr 7, s. 2411-2419Artikkel i tidsskrift (Fagfellevurdert)
  • 71.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Programme of activities: Will it break the ice for residential sector CDM projects?2008Inngår i: 14th Annual international sustainable development research conference, New Delhi, India, 2008Konferansepaper (Annet vitenskapelig)
  • 72.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Hemström, Kerstin
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Role of sellers/installers in the diffusion of energy efficient windows in Swedish detached houses2010Inngår i: SB10: Sustainable Community, 2010Konferansepaper (Fagfellevurdert)
  • 73.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Östersund.
    Mahapatra, Krushna
    Mittuniversitetet, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Östersund.
    Adoption of energy efficiency measures in Swedish detatched houses2009Inngår i: International Scientific Conference on Energy systems with IT,  March 11-12, in connection with 'Energitiget 2009', Stockholm, Sweden, 2009Konferansepaper (Fagfellevurdert)
    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.

  • 74.
    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 houses2012Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 89, nr 1, s. 329-338Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 75.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Influence of external actors in Swedish homeowners’ adoption of energy efficient windows2011Inngår i: World Renewable Energy Congress, 2011, Linköping, Sweden, May 8-11, 2011Konferansepaper (Fagfellevurdert)
  • 76.
    Nair, Gireesh
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Policy instruments to promote building energy efficiency from an end-user point of view2011Inngår i: ECEEE Summer study, Belambra Presqu'île de Giens, France, 6–11 June, European Council for an Energy Efficient Economy (ECEEE), 2011Konferansepaper (Fagfellevurdert)
  • 77.
    Nitze, Florian
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik. Department of Chemical and Biological Engineering, Chalmers University of Technology, Sweden.
    Sandström, Robin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Barzegar, Hamid Reza
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Hu, Guangzhi
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Mazurkiewicz, Marta
    Malolepszy, Artur
    Stobinski, Leszek
    Wågberg, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Direct support mixture painting, using Pd(0) organo-metallic compounds - an easy and environmentally sound approach to combine decoration and electrode preparation for fuel cells2014Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 2, nr 48, s. 20973-20979Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An inventive, fast and straight-forward approach for the direct preparation of fuel cell electrodes has been developed and tested. Our approach avoids long catalyst preparation and post-synthesis treatment. It reduces the use of chemicals and thereby concomitantly lowers the environmental impact and improves cost efficiency. It combines decoration of the support by palladium nanoparticles with electrode preparation through a simple one-step ink-painting and annealing process. Composites have been investigated by high resolution transmission electron microscopy, scanning electron microscopy, and Xray diffraction. Crystalline particles are well-attached and well-distributed on the support. Particles are of few nanometers in size and spherical for decorated Vulcan whereas they are larger and irregularly shaped for decorated helical carbon nanofibers (HCNFs). Electrodes with a metal loading of 0.8 mg cm(-2) have been tested in a direct formic acid fuel cell. Both the Vulcan and the HCNF electrodes show a similar and high power output of up to 120 mW mg(-1). They also show similar performances in deactivation experiments conducted at 200 mA cm(-2) even when using only high purity grade formic acid. After deactivation the electrodes show no structural damage, making them superior to most commercial catalysts. The electrodes can be completely regenerated to initial activity by simple treatment with water. The easy regeneration process indicates that CO-adsorption on the fuel cell anode catalyst is not the main poisoning mechanism responsible for electrode degeneration.

  • 78.
    Näslund, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energianalys av bergvärmeanläggning: Vid Akademiska Hus Norr AB2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Arbetet bestod i att utföra en energianalys av en bergvärmeanläggning åt uppdragsgivaren Akademiska Hus Norr AB vid Umeå universitets campus. Det var känt att värmepumpen var av för stor effekt för de två borrhål den var inkopplad emot, dock var det oklart hur mycket för stor och hur mycket energi som borrhålen överbelastades med. Metoden som användes vid energianalysen var prof. Bo Nordells ”handdimensionering” av bergvärme samt NIBEs dimensioneringskrav på köldbärartemperaturer. Bergvärmeanläggningen består av 2 borrhål på 100 respektive 120 m som belastas av en 10 kW värmepump. Vid dagens driftning av anläggningen skulle temperaturen på köldbäraren in till värmepumpen gå ned under -8°C vilket värmepumpen inte klarar. Resultatet blev att vid kontinuerlig värmeåterföring till borrhålen behövdes 2,5 kW värmeeffekt för att säkra en långsiktig drift. Tillsattes energin sommartid, vilket skulle kunna vara t.ex. solpaneler måste 22 kW tillsättas under perioden maj-september för att klara NIBEs dimensioneringskrav. Borrades ett nytt borrhål skulle detta behöva ha djupet 145 m för att klara kraven. Dock finns stor risk att laminär strömning uppstår under uppvärmningssäsong vilket gör att rekommendationen blir att vid åtgärd se resultaten som något av ett minimum och ta till en säkerhetsmarginal.

  • 79.
    Näsström, Emelie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Vindkraft-Drift under nordiskt klimat2016Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Vindkraft har blivit en allt viktigare del av svensk elproduktion i arbetet med att minska användningen av fossila bränslen. För att veta vilka platser som är lämpade för vindbruk har vindkarteringar tagits fram. Dessa innehåller ett flertal platser i norra Sverige med gynnsamma vindlägen. Ett problem med att etablera vindkraft på de norra breddgraderna är kylan. Då temperaturen är kring och under 0°C tenderar det att bildas is på rotorbladen. Detta medför att vindkraftverken stoppas med ekonomiska förluster som följd. Predikteringsmöjligheter av isbildning är därför ett önskvärt verktyg då det skulle ge vindkraftsägarna bättre möjligheter att planera produktion och försäljning av el. Målet med detta arbete var att ta fram ramverk för en prognosmodell för isbildning.

    Under arbetet genomfördes dels en förstudie som beskriver när atmosfärisk isbildning sker samt en analys av olika meteorologiska parametrar med betydelse för isbildning. De parametrar som analyserades var temperatur, vindriktning, vindhastighet, relativ luftfuktighet och nederbörd. Vid alla analyser studerades både hur värdena generellt har varit under mätperioden samt hur de har varit då det har rapporterats islarm, detta för att kunna se eventuella skillnader. Analyserna genomfördes enskilt för varje parameter samt genom att de olika parametrarna ställdes emot varandra för att se om det fanns något samband mellan olika parametrar. Utöver detta genomfördes även analyser för sex enskilda isperioder, det vill säga mätperioder där givare indikerat islarm. Dessa perioder användes även för beräkningar av ekonomiska förluster på grund av is.

    Arbetet har visat att atmosfärisk isbildning i stor grad beror på temperatur, relativ luftfuktighet, antal vattendroppar i luften samt storleken på vattendropparna. De två sista parametrarna är dock mycket komplicerade att kvantifiera och mäta. En generell approximation säger att atmosfärisk isbildning sker då temperaturen är under 0°C samtidigt som den relativa luftfuktigheten är 95 % eller högre. Men att prediktera isbildning genom att enbart studera dessa parametrar är inte helt korrekt då det är svårt att mäta den relativa luftfuktigheten vid låga temperaturer. Att studera vindriktningen kan också vara ett sätt att prediktera isbildning. I Sverige sker atmosfärisk isbildning främst vid sydöstlig vindriktning, förutsatt att den relativa luftfuktigheten är hög, och det är framförallt vid temperaturer mellan -5-0°C som de svåra isbildningarna uppträder. En annan parameter som kan studeras för att prediktera isbildning är nederbörd. Då det är nederbörd vid lägre temperaturer finns en risk att rotorbladen blir nedisade. Analyserna av vindhastigheten visade att denna parameter inte hade lika stor betydelse som de övriga parametrarna. Även om den inte har betydelse för att atmosfärisk isbildning ska inträffa har den betydelse för hastigheten på istillväxten.    

    Poängteras bör att mätdata inte uteslutande har varit parkdata och består därför av en viss osäkerhet. För att kunna ta fram mer kvalitativa prognosverktyg för att prediktera isbildning bör längre mätperioder användas i analyserna. En annan viktig åtgärd för att kunna förfina analyserna är att installera givare som ger korrekta värden i de vindparker som ska analyseras.  

    Under arbetet har det konstaterats att nedisning kan medföra stora ekonomiska förluster för ägarna. Detta motiverar definitivt en fortsättning på arbetet med att ta fram kvalitativa verktyg för att förutse och i ett tidigt skede detektera isbildning. En effektiv hantering av isproblematiken ökar lönsamheten, minskar slitage samt ger en mer effektiv planering av underhåll.

  • 80. Olofsson, Thomas
    et al.
    Nair, Gireesh
    Azizi, Shoaib
    Enkät om renovering och energieffektivisering2018Inngår i: Energi & Miljö, nr 1Artikkel, omtale (Annet (populærvitenskap, debatt, mm))
  • 81.
    Olsson, Jonas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Strategier för energieffektiv ombyggnation och drift av Sundsvalls sjukhus2019Independent thesis Advanced level (professional degree), 300 hpOppgave
    Abstract [en]

    Sundsvall hospital has many facilities that are heated by electrical air heating and the exhaust air is ventilated through so called exhaust windows. This leads to high air flows and temperature gradients in the rooms. In connection with renovations of building component M09 at the hospital the heat system is replaced with waterborne radiator heating, new supply air devices are installed and the external walls are reinsulated. This thesis aims to investigate how the exhaust windows is affected by lowered air flows and an alternative heating system and how optimal operations is achieved and also what should be prioritized in future renovations.

    In this thesis two identical rooms, one with the old electrical air heating and the other with waterborne radiators, was investigated. Air temperature, surface temperature and heating power was measured in both rooms with different air flows and heating losses was calculated. IDA ICE is a software for simulations of energy and indoor climate where the measured values was compared with the simulated in IDA ICE to verify a simulation model. IDA ICE was then used to calculate yearly energy use and thermal comfort for different operations and reinsulation thicknesses for both heating systems. 

    The results show that the energy use is mainly affected by the air flow in the room and not as much the heating system or thickness of reinsulation. The thermal comfort is improved with radiator-heating and thicker reinsulation increases the number of hours the room is too hot but the overall thermal comfort is better. The life cycle cost can be lowered with a thinner reinsulation in the room with radiator heating but not in the room with electrical air heating.

  • 82. Penya, Yoseba K.
    et al.
    Nieves, Juan Carlos
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Espinoza, Angelina
    Borges, Cruz E.
    Peña, Aitor
    Ortega, Mariano
    Distributed Semantic Architecture for Smart Grids2012Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 5, nr 11, s. 4824-4843Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The smart grid revolution demands a huge effort in redesigning and enhancing current power networks, as well as integrating emerging scenarios such as distributed generation, renewable energies or the electric vehicle. This novel situation will cause a huge flood of data that can only be handled, processed and exploited in real-time with the help of cutting-edge ICT (Information and Communication Technologies). We present here a new architecture that, contrary to the previous centralised and static model, distributes the intelligence all over the grid by means of individual intelligent nodes controlling a number of electric assets. The nodes own a profile of the standard smart grid ontology stored in the knowledge base with the inferred information about their environment in RDF triples. Since the system does not have a central registry or a service directory, the connectivity emerges from the view of the world semantically encoded by each individual intelligent node (i.e., profile + inferred information). We have described a use-case both with and without real-time requirements to illustrate and validate this novel approach.

  • 83.
    Persson, Erica
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energieffektiviserande åtgärder för befintlig kontorsfastighet på Umestans företagspark: Energy-efficiency measures for existing office building at Umestans Business Park2016Independent thesis Advanced level (professional degree), 300 hpOppgave
    Abstract [en]

    The work was conducted in the spring of 2016 on behalf of the ÅF Industry in Umeå. This project aimed to provide proposals on energy-saving measures for house 2 at Umestans Business Park based on the total specific purchased energy for 2015. Also for the 3rd floor in the same house suggestions on energy-saving measures were given. This was done with regard to the expected electricity use during 2016. Finally, an investigation on the possibility to classify the floors using of business-electricity was done.Initially was a literature study of today's classification system for buildings done. The focus was to see whether there is a possibility or not to classify leased office space. Both Swedish and international classification systems have been evaluated during the project.All the systems in the building were investigated and the total specific energy could be mapped. All the systems in the building were investigated and the total specific energy could be mapped. Based on the results of the operational-electricity that were emerged during the mapping of house 2, and based on the values of the electricity meter 83353 the business-electricity for floor 3 could be determined. Also for this area a mapping was made to see which areas the business-electricity went to.The results of the mapping of the building showed that the average energy consumption for the total specific purchased energy was 141,1 kWh/m2 per year. Of these districts heating stands for 63%. Of the total share of district heating 81% went to the radiators, this suggests that the building has large transmission losses. The inventory shows that the building's has a low use of electricity. This indicates that the technical systems were well installed with well-adapted operating times. The energy-saving measures that were found to reduce the building's losses were in the areas of windows, ventilation and solar shading. Energy-saving measures for the energy supplied were found in pumps, cooling and lighting.The result of floor 3 shows that the average use of business-electricity is at 36,36 kWh / m2 per year. Of these, 50% goes to lighting.From the results floor 3 could be classified to a Class B using the report "Energy performance of buildings - Energy Classification". To achieve a better classification requires change in the lightning on floor 3 as well as an analysis of any thinkable behavior change among the employees.

  • 84.
    Qu, Zhechao
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Ghorbani, Ramin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Valiev, Damir
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Schmidt, Florian M
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Calibration-free scanned wavelength modulation spectroscopy – application to H2O and temperature sensing in flames2015Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 23, nr 12, s. 16492-16499Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A calibration-free scanned wavelength modulation spectroscopy scheme requiring minimal laser characterization is presented. Species concentration and temperature are retrieved simultaneously from a single fit to a group of 2f/1f-WMS lineshapes acquired in one laser scan. The fitting algorithm includes a novel method to obtain the phase shift between laser intensity and wavelength modulation, and allows for a wavelengthdependent modulation amplitude. The scheme is demonstrated by detection of H2O concentration and temperature in atmospheric, premixed CH4/air flat flames using a sensor operating near 1.4 μm. The detection sensitivity for H2O at 2000 K was 4 × 10−5 cm−1 Hz-1/2, and temperature was determined with a precision of 10 K and absolute accuracy of ~50 K. A parametric study of the dependence of H2O and temperature on distance to the burner and total fuel mass flow rate shows good agreement with 1D simulations.

  • 85. Ramirez-Villegas, Ricardo
    et al.
    Eriksson, Ola
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Combined Environmental and Economic Assessment of Energy Efficiency Measures in a Multi-Dwelling Building2019Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 13, s. 1-13, artikkel-id 2484Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study is to assess how different renovation scenarios affect the environmental and economic impacts of a multi-dwelling building in a Nordic climate, how these aspects are correlated and how different energy carriers affect different environmental impact categories. In order to reduce greenhouse gas emissions, the European Union has set an agenda in order to reduce energy use in buildings. New buildings on the European market have a low replacement rate, which makes building renovation an important factor for achieving the European Union goals. In this study, eight renovation strategies were analyzed following the European Committee for Standardization standards for life cycle assessment and life cycle costs of buildings. This study covers all life cycle steps from cradle to grave. The renovation scenarios include combinations of photovoltaics, geothermal heat pumps, heat recovery ventilation and improved building envelopes. Results show that, depending on the energy carrier, reductions in global warming potential can be achieved at the expense of an increased nuclear waste disposal. It also shows that for the investigated renovation strategies in Sweden there is no correlation between the economic and the environmental performance of the building. Changing energy carriers in Sweden in order to reduce greenhouse gas emissions can be a good alternative, but it makes the system more dependent on nuclear power.

  • 86.
    Rebbling, Anders
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Fagerström, Jonathan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Steinvall, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Carlborg, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Öhman, Marcus
    Energy Engineering, Division of Energy Science, Department of Engineering Sciences & Mathematics, Luleå University of Technology.
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Reduction of Alkali Release by Two Fuel Additives at Different Bed Temperatures during Grate Combustion of Woody Biomass2019Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, nr 11, s. 11041-11048Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of small- and medium-scale combustion of biomass for energy utilization is expected to grow in the coming decades. To meet standards and legislation regarding particle emissions and to reduce corrosion and deposit formation, it is crucial to reduce the release of alkali species from the fuel. This can be achieved by capturing the volatile alkali in the residual bottom ash as more thermally stable compounds. In this work, we investigate the combination of primary measures, i.e., process parameters and fuel additives, for reduction of the release of K and Na from the fuel bed during fixed bed combustion. In addition, the influence of these combined measures on fine particle emissions was explored. The results showed a clear influence of the process parameters, herein bed temperature, and that a significant reduction of the alkali release and PM1 emissions can be achieved by correct settings. Furthermore, the application of additives (kaolin and diammonium sulfate) reduced both K and Na release even further. The observed effects on the release behavior was mainly explained by the formation of KAlSiO4 and K2SO4 during addition of kaolin and diammonium sulfate, respectively. This work therefore emphasizes the importance of good control over the fuel bed conditions, especially temperature, when these additives are applied. To reduce the potential deactivation (for kaolinite) and melting (for K2SO4), the control of bed temperature is vital. Thus, it was concluded that the release of volatile alkali species and related fine particle emissions in small- and medium-scale biomass heat and power plants using wood fuels could be significantly reduced by a correct combination of controlling the combustion parameters and the use of fuel additives.

  • 87.
    Rossing, Jonas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Solvärme i småskaligt fjärrvärmenät: Förutsättningar och möjligheter för Umeå Energi2011Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Satsningar på förnyelsebar energiproduktion är en viktig del i strävan efter ett mer hållbart samhälle. Att ta till vara på energin i solinstrålningen är både miljövänligt och relativt enkelt. Syftet med detta arbete har varit att undersöka möjligheterna att integrera solenergi i Umeå Energis mindre fjärrvärmenät i Hörnefors.

    De alternativ som har studerats är två olika anslutningsmöjligheter av solfångaranläggningar till fjärrvärmenätet. Med det första anslutningsalternativet, som kallas primäranslutning, kan en solfångaranläggning leverera värme direkt ut på fjärrvärmenätets primärledning, vilket gör att solvärmen blir tillgänglig för alla abonnenter på nätet. Med det andra alternativet, som kallas sekundäranslutning, kan en solfångaranläggning endast leverera värme till en abonnent, i detta fall ett badhus.

    Förutom de olika anslutningsalternativen har också olika typer av solfångare undersökts. Detta innefattar en plan solfångare, en vakuumrörsolfångare, en hybridsolfångare, samt en poolsolfångare.

    Resultaten visade att upp till 20 % av fjärvärmenätets totala behov kunde ersättas med solvärme vid primäranslutning och runt 0,7 % vid sekundäranslutning. Dock är inget av alternativen i dagsläget ekonomiskt lönsamt. Det alternativ som var närmast att uppnå lönsamhet var den sekundäranslutna poolsolfångaranläggningen. Med det alternativet erhölls en nuvärdeskvot på 0,43. De andra alternativen låg mellan 0,11 och 0,22.

  • 88.
    Sandra, Schusser
    et al.
    Department of Forest Economics, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Jaraite, Jurate
    Umeå universitet, Samhällsvetenskapliga fakulteten, Centrum för miljö- och naturresursekonomi (CERE). Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Nationalekonomi.
    Explaining the interplay of three markets: green certificates, carbon emissions and electricity2018Inngår i: Energy Economics, ISSN 0140-9883, E-ISSN 1873-6181, Vol. 71, s. 1-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The European Union's Emissions Trading System (EU ETS) and the Swedish-Norwegian Tradable Green Certificate System (Swedish-Norwegian TGC system) are two market-based instruments that have the overlapping goals to mitigate greenhouse gas (GHG) emissions by shifting economies to cleaner energy sources. Understanding the price signals and interactions of these two newly created markets is essential for all decision makers – regulators and direct market participants – who aim to reach the predefined policy goals in the most efficient manner. The interaction between these policy instruments has been widely examined from the theoretical perspective. This research contributes to the literature by empirically examining the interplay between the prices of three markets: (1) the price of tradable green certificates (TGC) in the Swedish-Norwegian TGC system, (2) the price of carbon in the EU ETS and (3) the price of electricity in the Nord Pool. We use a multivariate vector-autoregressive (VAR) approach to take into account the endogenous relationships between these prices. Our empirical results do not support the theoretical considerations that the impacts of carbon prices on TGC prices and hence on renewable electricity production are negative. Contrary, we find that, to date, increases in carbon prices positively affect TGC prices in the short run.

  • 89.
    Sandström, Robin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Innovations in nanomaterials for proton exchange membrane fuel cells2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Hydrogen technologies are rapidly receiving increased attention as it offers a renewable energy alternative to the current petroleum-based fuel infrastructure, considering that continued large-scale use of such fossil fuels will lead to disastrous impacts on our environment. The proton exchange membrane fuel cell should play a significant role in a hydrogen economy since it enables convenient and direct conversion of hydrogen into electricity, thus allowing the use of hydrogen in applications particularly suited for the transportation industry. To fully realize this, multiple engineering challenges as well as development of advanced nanomaterials must however be addressed.

    In this thesis, we present discoveries of new innovative nanomaterials for proton exchange membrane fuel cells by targeting the entire membrane electrode assembly. Conceptually, we first propose new fabrication techniques of gas diffusion electrodes based on helical carbon nanofibers, where an enhanced three-phase boundary was noted in particular for hierarchical structures. The cathode catalyst, responsible for facilitating the sluggish oxygen reduction reaction, was further improved by the synthesis of platinum-based nanoparticles with an incorporated secondary metal (iron, yttrium and cobalt). Here, both solvothermal and high-temperature microwave syntheses were employed. Catalytic activities were improved compared to pure platinum and could be attributed to favorably shifted oxygen adsorption energies as a result of successful incorporation of the non-precious metal. As best exemplified by platinum-iron nanoparticles, the oxygen reduction reaction was highly sensitive to both metal composition and the type of crystal structure. Finally, a proton exchange membrane based on fluorine and sulfonic acid functionalized graphene oxide was prepared and tested in hydrogen fuel cell conditions, showing improvements such as lowered hydrogen permeation and better structural stability. Consequently, we have demonstrated that there is room for improvement of multiple components, suggesting that more powerful fuel cells can likely be anticipated in the future.

  • 90.
    Sandström, Robin
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Annamalai, Alagappan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Boulanger, Nicolas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Ekspong, Joakim
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Talyzin, Aleksandr V.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Mühlbacher, Inge
    Wågberg, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Evaluation of Fluorine and Sulfonic Acid Co-functionalized Graphene Oxide Membranes in Hydrogen Proton Exchange Membrane Fuel Cell Conditions2019Inngår i: Sustainable Energy & Fuels, ISSN 2398-4902, Vol. 3, nr 7, s. 1790-1798Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of graphene oxide (GO) based membranes consisting of self-assembled flakes with a lamellar structure represents an intriguing strategy to spatially separate reactants while facilitating proton transport in proton exchange membranes (PEM). Here we chemically modify GO to evaluate the role of fluorine and sulfonic acid groups on the performance of H2/O2 based PEM fuel cells. Mild fluorination is achieved by the presence of hydrogen fluoride during oxidation and subsequent sulfonation resulted in fluorine and SO3- co-functionalized GO. Membrane electrode assembly performance in low temperature and moderate humidity conditions suggested that both functional groups contribute to reduced H2 crossover compared to appropriate reference membranes. Moreover, fluorine groups promoted an enhanced hydrolytic stability while contributing to prevent structural degradation after constant potential experiments whereas sulfonic acid demonstrated a stabilizing effect by preserving proton conductivity.

  • 91. Sarmad, Shokat
    et al.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Ji, Xiaoyan
    Carbon Dioxide Capture with Ionic Liquids and Deep Eutectic Solvents: A New Generation of Sorbents2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 2, s. 324-352Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High cost and high energy penalty for CO2 uptake from flue gases are important obstacles in large-scale industrial applications, and developing efficient technology for CO2 capture from technical and economic points is crucial. Ionic liquids (ILs) show the potential for CO2 separation owing to their inherent advantages, and have been proposed as alternatives to overcome the drawbacks of conventional sorbents. Chemical modification of ILs to improve their performance in CO2 absorption has received more attention. Deep eutectic solvents (DESs) as a new generation of ILs are considered as more economical alternatives to cope with the deficiencies of high cost and high viscosity of conventional ILs. This Review discusses the potential of functionalized ILs and DESs as CO2 sorbents. Incorporation of CO2 -philic functional groups, such as amine, in cation and/or anion moiety of ILs can promot their absorption capacity. In general, the functionalization of the anion part of ILs is more effective than the cation part. DESs represent favorable solvent properties and are capable of capturing CO2 , but the research work is scarce and undeveloped compared to the studies conducted on ILs. It is possible to develop novel DESs with promising absorption capacity. However, more investigation needs to be carried out on the mechanism of CO2 sorption of DESs to clarify how these novel sorbents can be adjusted and fine-tuned to be best tailored as optimized media for CO2 capture.

  • 92.
    Selling, Oscar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Jämförelse av uppvärmningssystem för samfällighetsförening: En ekonomisk och miljömässig analys2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    I detta arbete har olika uppvärmningssystem för en samfällighetsförening jämförts ekonomiskt och miljömässigt. Den ekonomiska jämförelsen har gjorts ur ett livscykelkostnadsperspektiv mellan fjärrvärme och olika lösningar med värmepumpar. De miljömässiga aspekterna jämfördes genom att undersöka utsläppen under drift utifrån synsätten ursprungsmärkt el och medelel samt genom primärenergianvändningen. 

    Arbetet är utfört på uppdrag av Vargskinnets samfällighetsförening i Mariedal, Umeå. Samfällighetsföreningen består av 128 st kedjehus som idag får sin uppvärmning från fjärrvärme.

    För arbetet har två stycken alternativ med värmepumpar jämförts med uppvärmning av enbart fjärrvärme. Ena alternativet bestod av fem bergvärmepumpar på totalt 400 kW som stod för baslasten av uppvärmingen och fjärrvärme användes som spetslast samt för att värma varmvatten. Det andra alternativet bestod av tio bergvärmepumpar och en total effekt på 800 kW där pumparna användes som baslast för uppvärming samt varmvattenberedning och el användes som spetslast när värmepumparna inte räckte till.

    Alternativen jämfördes ekonomiskt genom beräkna LCC (Life Cycle Cost) för alla alternativ. Resultaten visade att alternativet med tio värmepumpar var det mest lönsamma alternativet som gav en besparing på ca. 7,3 milj kr. Även miljömässigt visade sig lösningarna med bergvärmepumpar vara bra då de gav reducerade utsläpp jämfört med enbart fjärrvärme. Jämförelse av primärenergianvändningen gav inga konkreta resultat vad som var bäst. Det beror på hur primärenergi för vissa bränsle som t.ex. avfall och restprodukter tas i beaktning för vilket alternativ som är bäst.

  • 93. Sepman, Alexey
    et al.
    Ögren, Yngve
    Qu, Zhechao
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Wiinikka, Henrik
    Schmidt, Florian M.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Umeå University.
    Real-time in situ multi-parameter TDLAS sensing in the reactor core of an entrained-flow biomass gasifier2017Inngår i: Proceedings of the Combustion Institute, ISSN 1540-7489, E-ISSN 1873-2704, Vol. 36, nr 3, s. 4541-4548Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tunable diode laser absorption spectroscopy (TDLAS) was used to measure several important process parameters at two different locations inside the reactor of an atmospheric, air-blown 0.1 MWth biomass gasifier. Direct TDLAS at 2298 nm was employed for carbon monoxide (CO) and water vapor (H2O), calibration-free scanned wavelength modulation spectroscopy at 1398 nm for H2O and gas temperature, and direct TDLAS at 770 nm for gaseous elemental potassium, K(g), under optically thick conditions. These constitute the first in situ measurements of K(g) and temperature in a reactor core and in biomass gasification, respectively. In addition, soot volume fractions were determined at all TDLAS wavelengths, and employing fixed-wavelength laser extinction at 639 nm. Issues concerning the determination of the actual optical path length, as well as temperature and species non-uniformities along the line-of-sight are addressed. During a 2-day measurement campaign, peat and stem wood powder were first combusted at an air equivalence ratio (lambda) of 1.2 and then gasified at lambdas of 0.7, 0.6, 0.5, 0.4 and 0.35. Compared to uncorrected thermocouple measurements in the gas stream, actual average temperatures in the reactor core were significantly higher. The CO concentrations at the lower optical access port were comparable to those obtained by gas chromatography at the exhaust. In gasification mode, similar H2O values were obtained by the two different TDLAS instruments. The measured K(g) concentrations were compared to equilibrium calculations. Overall, the reaction time was found to be faster for peat than for stem wood. All sensors showed good performance even in the presence of high soot concentrations, and real-time detection was useful in resolving fast, transient behaviors, such as changes in stoichiometry. Practical implications of in-situ TDLAS monitoring on the understanding and control of gasification processes are discussed.

  • 94.
    Shukla, Shashi Kant
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Nikjoo, Dariush
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Is basicity the sole criterion for attaining high carbon dioxide capture in deep-eutectic solvents?2020Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A critical analysis of the role of Hammett basicity (H−) and aqueous basicity (pKa) in CO2 uptake in deep-eutectic solvents (DESs) suggests that neither H− nor pKa correlates with the CO2 w/w% capacity in the studied DESs. Instead, strong “synergistic interactions” between donor and acceptor moieties satisfactorily relate to the w/w% of CO2 in DESs.

  • 95.
    Simonsen, Ingeborg
    et al.
    SINTEF Building and Infrastructure.
    Murphy, Mark
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Bakken, Bjørn H.
    SINTEF Energy Research.
    Kristjansdottir, Torhildur F
    SINTEF Building and Infrastructure.
    Early-phase energy supply planning2014Inngår i: Utopia revisited: towards a carbon-neutral neighbourhood at Brøset / [ed] Eli Støa, Stig Larssæther, Annemie Wyckmans, Bergen, Norway: Fagbokforlaget, 2014, s. 305-327Kapittel i bok, del av antologi (Fagfellevurdert)
  • 96.
    Strandberg, Anna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Fuel conversion and ash formation interactions: a thermochemical study on lignocellulosic biomass2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biomass is considered to be CO2 neutral, and to be able to reduce the dependency on fossil fuels the need for expanded and sustainable biomass feedstock is increasing. Ash-related problems are some of the most important aspects of this increasing use of new biomass assortments in thermal energy conversion systems. An improved basic understanding of fuel conversion, ash formation, ash transformation and ash interactions with the converting fuel is therefore important.

    In the present thesis, the main objective was to provide new knowledge on thermochemical fuel conversion, specifically on how ash formation interacts with fuel conversion for lignocellulosic biomasses. The main methods used were experimental characterization of decomposition behavior and analysis of morphology and elemental composition of samples, using different appliances, analytical methods and fuels. Multivariate data analysis was successfully used on thermogravimetric data for prediction of compositional data and fuel properties.

    New, detailed explanations of structural changes in char morphology and ash properties during conversion were provided including descriptions of the influences of ash formation on fuel conversion rates under different conditions. The influences were found different depending on both particle size and ash composition. One implication of these findings is that for fuels with low temperature melting ash, the diffusion barrier formed causes difficulties for typical thermogravimetric experiments aiming at determination of reactivity in the kinetically controlled regime. This is recommended to carefully consider for future studies. On a single pellet level, char encapsulation was not found to dominate and limit gas transport and conversion for any of the fuels tested. In practical applications, however, the situation may be different with thick ash layers accumulating on a fuel bed surface. Another important finding was the extensive formation of cracks and internal cavities during combustion of pellets, providing new insights in the fundamentals of fuel conversion.

    Clean woody fuels, rich in calcium, formed a porous ash layer with no sign of limiting char conversion rates. The phase chemical transformations involving carbonate and oxide formation from poplar pellets was studied in detail. For grassy fuels, on the other hand, low melting point silicates are expected to form. The physical properties of K-Ca-silicates from silicon rich straw fuels were also characterized, providing new insights on ash formation on micrometer scale resolution; at high temperature, the silicate melt formed bubbles on the surface that partially covered the char, while for lower temperature a more rigid net structure was formed.

  • 97.
    Svedin, Claes
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Umeå Universitet.
    An energy balance analysis for current and future production of paper at Mondi Dynäs paper mill: A development project of current and future scenarios for the steam and condensate network with proposals for enhanced utilization of energy2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Mondi Dynäs is a pulp and paper producer in the north of Sweden close to the town Kramfors. Last year Mondi Dynäs produced 231,404 tons of Kraft paper. In order to increase their production to 300,000 tons of paper per year this study was done in order to investigate how the increased biomass flow would affect the generation of steam along with the steam and condensate balance. This study started with a mapping of the current steam and condensate balance for one winter period January – Mars and one summer period July – September 2015. The resulting balance is used as reference period for the development of the future steam and condensate scenario where Mondi Dynäs will achieve the targeted production of 300,000 tons of paper per year.

    The future model shows that the future production of paper will give an abundance of biomass since the generation of steam will be more than sufficient. For the winter period the venting of steam over roof could be derived to 11.9 tons per hour and 34.4 tons per hour during the summer period. This can be compared to the current situation where the winter period gave an average steam blow out of 8.7 tons per hour and for the summer period 13.1 tons per hour. To utilize the accumulated energy from these energy streams, three different scenarios was studied.

    The first scenario were a future installation of a backpressure turbine along with a condensing turbine section. The new turbine would be attached to the highest pressure level at 65.5 bar and have a backpressure exhaust at 20 bar which will give a power of 7.6 MWe.

    The second scenario included the implementation of a new condensing turbine with the current system design for the steam network and boilers. This turbine would be attached to the 3.5 bar network and give the electricity power of 1.9 MWe.

    The third scenario included the installation of a new bark dryer. This would give Mondi Dynäs the possibility to sell bark to an external actor on the energy market. From derived figures in the future scenario model it would be possible to sell 108,144 MWh of bark while running the bark boiler.

    Mondi Dynäs AB is recommended to add a new condensing turbine to their steam network. The new turbine would be able to produce 1.9 MWe and need a cooling water flow of 190 tons of water per hour. Derived figures for the investment shows a NPV of 0.6 MEUR and the IRR value of 31 %

  • 98.
    Törnroth, Jonatan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Beräkningsmodell för osymmetrisk last och produktion i lågspänningsnätet2015Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Produktion i lågspänningsnätet ökar kraftigt, bara under år 2014 dubblerades antalet nätanslutna solcellsanläggningar i Sverige. Utvecklingen ser ut att hålla i sig och då dessa anläggningar ofta är små är det troligt att flera ansluts genom en enfasigt ansluten växelriktare.

    Ett symmetriskt trefassystem består av tre fasspänningarna med samma amplitud, frekvens och förskjutna 120˚ från varandra. Laster och produktionsenheter som inte är trefasigt nätanslutna ger upphov till ett osymmetriskt driftfall. Detta arbete syftar till att undersöka hur spänningen påverkas av osymmetriska laster och produktionsenheter i Vattenfalls lågspänningsnät. Målet med arbetet är att skapa ett beräkningsverktyg som kan användas av Vattenfall Eldistribution för att undersöka hur spänningen påverkas vid olika osymmetriska driftfall.

    Beräkningsvertyget har skapats i Matlab och utgår från kända värden för spänningen i matningspunkten och impedansen mellan matningspunkten och anslutningspunkten. Dessutom anges effekt och effektfaktor för eventuell produktion och förbrukning i respektive fas. Beräkningsmodellen beräknar spänningar och strömmar i anslutningspunkten samt spänningens osymmetri.

    Verifiering av beräkningsmodellen har utförts genom att jämföra beräknat resultat med ”Kurvor för förenklad bedömning av nätstyrka” som återfinns i MIKRO-handboken, utgiven av branschorganisationen Svensk Energi. En fältstudie har utförts på en enfasigt nätansluten solcellsanläggning. Mätresultatet från denna har jämförts med resultat från beräkningsmodellen. Dessutom har laboratoriemätningar på en försöksuppställning genomförts. Försöksuppställningen modellerade en lågspänningskund ansluten till ett svagt nät, med enfasigt ansluten produktion och last. Mätresultatet från försöksuppställningen jämfördes med resultat från beräkningsmodellen.

    I jämförelse mellan den framtagna beräkningsmodellen och MIKRO-handboken konstateras att de stämmer överens. I jämförelse med mätresultat från fältstudien konstateras att beräkningsmodellen troligtvis räknar rätt men att mätningarna inte enbart kan användas för att verifiera modellen då det är en liten spänningsvariation och många troliga felkällor. Resultatet från försöksuppställningen konstateras överensstämma med beräknade värden och kan därför bekräfta att beräkningsmodellen är korrekt utformad.

  • 99.
    Upadhyayula, Venkata K.K.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Parvatker, Abhijeet G.
    Baroth, Anju
    Shanmugam, Kavitha
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lightweighting and electrification strategies for improving environmental performante of passenger cars in India by 2030: A critical perspective based on life cycle assessment2019Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 209, s. 1604-1613Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Indian automotive industry is faced with an unenviable challenge of achieving a sustainable growth in one of the largest markets. Adapting to increasingly strict environmental norms by the government committed to reducing the national greenhouse gas emissions, growing concerns amongst the citizens over the deteriorating air quality in the cities are the major environmental sustainability challenges for the auto industry in next decade. In this study, we analyze the potential benefits of vehicle light weighting and introduction of electric vehicles through a cradle-to-grave life cycle assessment (LCA) of a standard sedan passenger vehicle. Based on the LCA results, five different scenarios are envisioned with different composition of the passenger vehicle fleet in 2030. These scenarios are used to analyze three key enviro-economical goals for India; (1) dependency on crude oil imports, (2) GHG emission reduction targets and (3) improvement in urban air quality. The results indicate that global warming potential (GWP) and fossil depletion impacts of ICEs can be reduced by 17%, while metal depletion reduces by 34% per vehicle with lightweighting. However, increase in freshwater ecotoxicity impact by 57% is one of the trade-offs. The GWP of a compact BEV powered with current (2014) and 2030 electricity grid mixes is 36% and 16% higher than petrol car. The GWP of a sub-compact BEV powered with current grid mix is 9% higher with current grid mix but 14% lower than petrol cars when powered with 2030 electricity grid mix. Crude oil consumption and GHG emissions are reduced by 20% with lightweight ICE fleet. Whereas, up to 45% reduction in crude oil consumption and 65% improvement in urban air quality can be achieved with BEV penetration scenarios. (C) 2018 Elsevier Ltd. All rights reserved.

  • 100.
    Vallmark, Hanna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energikartläggning i stora företag2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Detta examensarbete har utförts i samarbete med Sweco Systems i Umeå. Uppdraget var att ge en insikt i vad den nya lagen om energikartläggningar innebär för företag. För att förtydliga vad en energikartläggning är har en fallstudie utförts i form av en energikartläggning på Öppen gemenskaps verksamhetslokaler i Umeå.Studien kring hur stora företag tänker kring den nya lagen om energikartläggningar har varit utformad med telefonintervjuer av 11 stycken företag. Företagen har både fått omfattande och korta frågor som har sammanställts och resulterat i diagram och förklarande text. Det har visat sig att företagen är positiva till den nya lagen men att de flesta sedan innan redan arbetar med energieffektivisering. 80 % av de företag som sedan tidigare hade en uttalad strategi för energieffektivisering upplevde att energieffektiviseringsarbetet var högt prioriterat. Inget av de företagen som sa att de hade en energieffektiviseringsstrategi upplevde att den var lågt prioriterad. En majoritet upplevde att de fått tillräcklig information om vad lagen innebär för dem och ungefär 75 % av de tillfrågade företagen trodde att de skulle ha nytta av att göra en kartläggning. 73 % av de intervjuade företagen trodde att den nya lagen kommer minska energianvändningen i Sverige.För att visa mer konkret på vad lagen om energikartläggningar handlar om har en case-study utförts i form en energikartläggning. Denna kartläggning utfördes på en fastighet i centrala Umeå och mynnade ut i diagram över energiflöden och några åtgärdsförslag som fastighetsägarna kan följa för att minska sin energianvändning. Energikartläggningen omfattade tre byggnader som såg olika ut och där det bedrevs olika verksamheter. Energibalansberäkningar utfördes både separat för byggnaderna och för hela fastigheten ihopslaget. För alla byggnader tillsammans visade det sig att transmissionsförlusterna överlägset stod för den största energianvändningen, sedan stod förlusterna för ventilation, el som inte tillgodoser byggnaderna med värme, ofrivillig ventilation och tappvarmvatten. Den tillförda energin kom från fjärrvärme, el och personvärme.

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