Change search
Refine search result
3456789 251 - 300 of 417
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 251. Lundén, Torbjörn
    et al.
    Abrahamsson, Oscar
    Extraktion av kolväten ur sågspån vid ångtorkningsprocess: Sammansättning av tunga och lättflyktiga kolväten i sågspån och kondensat2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Miljöfrågor om bränsleanvändning tar allt större plats i världen till följd av att människor blir allt mer medvetna om fossila bränslens negativa påverkan på miljön. Användningen av mer miljövänliga biobränslen ökar globalt och däribland förbrukningen av energipellets. Användningen av energipellets har varit under utveckling i omkring 20 år. Till produktionen av energipellets är en av de vanligaste råvarorna sågspån. Sågspån uppkommer som en biprodukt i sågverksindustri och säljs från sågverken till pelletsfabriker. För att kunna producera energipellets av sågspån bör ha en fukthalt på 8-12 %. Obehandlat sågspån har en fukthalt på omkring 50 % och genomgår därför en torkprocess. I Sveg finns en av Nordens största anläggningar för torkning av torv och sågspån. Anläggningen är konstruerad för torkning av torv men har nu delvis bytts ut mot sågspån. I samband med detta byte har det nu uppstått problem med pålagringar i torkningsprocessen. Det har framkommit att det är kolväten från extraktivämnena i veden/sågspånet som bildar dessa pålagringar. Enligt tidigare studier har det påvisats att det är de tyngre kolvätena som bildar dessa pålagringar men att det också möjligt för lättare kolväten att lösa upp de tyngre kolvätena. I denna studie skall det undersökas hur mycket av kolvätet i extraktivämnena som är lättflyktiga respektive tunga. Detta gjordes för kondensat från torkningsångan hämtat från Härjeåns Energi AB och för färskt, lagrat och gammalt sågspån hämtat från en skogsindustri anläggning.För sågspånet utarbetades en torkningsprocess i Karlstads Universitet för att efterlikna den kemiska process som sker på anläggningen i Sveg. Extraktionsprocessen återskapades genom att koka en bestämd mängd sågspån i gastäta burkar under olika tidsintervall. Med hjälp av Hach-langeinstrument har total mängd organiskt kol (TOC) och flyktiga fettsyror (VFA) uppmätts. Mätningar på lättflyktiga kolväten (VOC) utfördes med hjälp av en flamjonsdetektor (FID). I arbetet studerades även spånens och kondensatens pH-värden.Resultatet visar att gammalt spån innehåller större mängd TOC och mindre mängd VOC jämfört med färskare spån. Anledningen är att sågspånet under lagringsperioden utsätts för en biologisk nedbrytning. Mikroorganismer bryter då ner längre kolvätekedjor till kortare fettsyror, detta stöds av resultatet ur testerna på pH-värdet blir lägre i samband med hur länge spånet lagrats, samtidigt som mängden fettsyror i spånet ökar.

  • 252.
    Mattsson, Lisa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Williams, Helén
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Berghel, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Waste of fresh fruit and vegetables at retailers in Sweden: Measuring and calculation of mass, economic cost and climate impact2018In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 130, p. 118-126Article in journal (Refereed)
    Abstract [en]

    Food waste is a significant problem for environmental, economic and food security reasons. The retailer, food service and consumers have been recognised as the parts of the food supply chain where the possibility of reducing food waste is greatest in industrialised countries. In this study, primary data on fresh fruit and vegetables (FFV) waste collected through direct measurements in three large retail stores in Sweden were analysed from the perspectives of wasted mass, economic cost and climate impact. A method of measuring and calculating the economic cost of FFV waste was developed and includes the cost of wasted produce, the cost of personnel time for waste management and the cost of waste collection and disposal. The results show that seven FFV categories, which have been termed "hotspot categories", contributed to the majority of the waste, both in terms of wasted mass, economic cost and climate impact. The "hotspot categories" are apple, banana, grape, lettuce, pear, sweet pepper, and tomato. The cost benefit analysis conducted showed that it is economically wise to invest in more working time for employees in waste management to accomplish a reduction of wasted mass and climate impact without an economic loss for the store. These results are relevant for supporting the implementation of policies and initiatives aimed at food waste reduction at retail level.

  • 253.
    Mohammadi, Ali
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Sandberg, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Govindarajan, Venkatesh
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Eskandari, Samieh
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Dalgaard, Tommy
    Aarhus University, Denmark.
    Granström, Karin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Environmental analysis of producing biochar and energyrecovery from pulp and papermill biosludge2019In: Journal of Industrial Ecology, ISSN 1088-1980, E-ISSN 1530-9290Article in journal (Refereed)
    Abstract [en]

    Sweden is one of the largest exporters of pulp and paper products in the world. It follows that huge quantities of sludge rich in carbonaceous organic material and containing heavy metals are generated. This paper carried out a comparative environmental analysis of three different technologies, which can be adopted to produce biochar and recover energy from the biosludge, using landfilling as the reference case. These three thermochemical biosludge management systems—using incineration, pyrolysis, and hydrothermal carbonization (HTC)—were modeled using life cycle assessment (LCA). Heat generated in the incineration process (System A) was considered to be for captive consumption within the kraft pulp mills. It was assumed that the biochars—pyrochar and hydrochar—produced from pyrolysis (System B) and HTC (System C), respectively, were added to the forest soils. The LCA results show that all the alternative systems considerably improve the environmental performance of biosludge management, relative to landfilling. For all systems, there are net reductions in greenhouse gas emissions (–0.89, –1.43, and –1.13 tonnes CO2‐equivalent per tonne dry matter biosludge in Systems A, B, and C, respectively). System B resulted in the lowest potential eutrophication and terrestrial ecotoxicity impacts, whereas System C had the least acidification potential. The results of this analysis show that, from an environmental point of view, biochar soil amendment as an alternative method for handling pulp and paper mill biosludge is preferable to energy recovery. However, an optimal biochar system needs to factor in the social and economic contexts as well.

  • 254.
    Moniruzzaman, Syed
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Divergent trends in emergency department visits for poisonings by intent in Varmland, Sweden2016In: Injury Prevention, ISSN 1353-8047, E-ISSN 1475-5785, Vol. 22, p. A227-A227Article in journal (Other academic)
  • 255.
    Mossberg, Magnus
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics (from 2013).
    Söderström, Torsten
    Uppsala University.
    On covariance matching for multiple input multiple output errors-in-variables systems2012In: IFAC Proceedings Volumes / [ed] Kinnaert, Michel, Elsevier, 2012, Vol. 45, p. 1371-1376Conference paper (Refereed)
  • 256.
    Mugiraneza, Theodomir
    et al.
    KTH; University of Rwanda, Rwanda.
    Haas, Jan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Ban, Yifang
    KTH.
    Spatiotemporal analysis of urban land cover changes in Kigali, Rwanda using multitemporal landsat data and landscape metrics2017In: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-3/W2, 2017, International Society for Photogrammetry and Remote Sensing , 2017, p. 137-144Conference paper (Refereed)
    Abstract [en]

    Mapping urbanization and ensuing environmental impacts using satellite data combined with landscape metrics has become a hot research topic. The objectives of the study are to analyze the spatio-temporal evolution of urbanization patterns of Kigali, Rwanda over the last three decades (from 1984 to 2015) using multitemporal Landsat data and to assess the associated environmental impact using landscape metrics. Landsat images, Normalized Difference Vegetation Index (NDVI), Grey Level Co-occurrence Matrix (GLCM) variance texture and digital elevation model (DEM) data were classified using a support vector machine (SVM). Eight landscape indices were derived from classified images for urbanization environment impact assessment. Seven land cover classes were derived with an overall accuracy exceeding 88% with Kappa Coefficients around 0.8. As most prominent changes, cropland was reduced considerably in favour of built-up areas that increased from 2,349 ha to 11,579 ha between 1984 and 2015. During those 31 years, the increased number of patches in most land cover classes illustrated landscape fragmentation, especially for forest. The landscape configuration indices demonstrate that in general the land cover pattern remained stable for cropland but it was highly changed in built-up areas. Satellite-based analysis and quantification of urbanization and its effects using landscape metrics are found to be interesting for grassroots and provide a cost-effective method for urban information production. This information can be used for e.g. potential design and implementation of early warning systems that cater for urbanization effects.

  • 257.
    Muntean, Adrian
    Eindhoven University of Technology.
    Continuum Modeling: An Approach Through Practical Examples2015Book (Other academic)
  • 258.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    A review of Industrial Metabolism: Restructuring for Sustainable Development1996In: Ecological Economics, 17Article, book review (Refereed)
  • 259.
    Månsson, Bengt
    Karlstad University, Division for Engineering Sciences, Physics and Mathematics.
    Att nyttja det skogen ger2004In: Inte bara träd: hållbart mångbruk av skogslandskapet / [ed] Gunilla Almered Olsson, Gabriel Bladh, Bengt Månsson & Lars Nyberg, Stockholm: Carlsson Bokförlag, 2004, p. 113-120Chapter in book (Other academic)
  • 260.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Energy Efficiency and Environmental Loads of Drying Systems2005Conference paper (Refereed)
    Abstract [en]

    Some of the key issues in the area of combined environmental and energy optimization of integrated industrial process systems are discussed, with emphasis on systems that include drying processes. This involves minimization of both energy resource losses and harmful emissions. The risks for environmental sub-optimization in wood drying systems are analyzed on the basis of concrete examples from wood fuel pellet production systems. In particular, the role of terpene emissions is discussed. Important concepts for energy efficiency optimization are discussed. In particular, fundamental problems hindering the use of the exergy concept for systems integration and optimization are described and the possibilities for resolving them are analyzed. The well-known reference state problem is shown to be part of a larger, more intractable problem. In this context, the roles of thermodynamic non-equilibrium and rate constraints are elaborated. It is argued that in order to reach broad applicability of the exergy concept it is necessary to develop a modified concept, which takes into account not only the usual constraints emanating from the three laws of thermodynamics but also other physical as well as technical constraints

  • 261.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Entropy Production in Oscillating Chemical Systems1985In: Zeitschrift für Naturforschung, 40a, 877-885Article in journal (Refereed)
    Abstract [en]

    The entropy production in oscillating homogeneous chemical systems is investigated by analyzing the difference between the average entropy production rate in a stable periodic oscillatory mode and in the corresponding unstable stationary state. A general analytical expression for this difference in the neighborhood of a Hopf bifurcation is derived. The entropy production in two typical models of chemical systems with unstable stationary states and stable periodic oscillations is investigated, using fixed concentrations as conrol parameters. The models exemplify both positive and negative entropy production rate differences. One of the investigated models has four free concentrations, the other three. The rate expressions are given by second order mass action kinetics with reverese reactions taken into account. The flows of reactants and products are controlled so that only the free concentrations vary, and the entropy of mixing associated with these flows is discussed

  • 262.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Fundamental Problems with Energy Theories of Value1992Conference paper (Refereed)
  • 263.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Jorden1992In: Miljö från A till Ö, Höganäs: Bra Böckers Förlag , 1992Chapter in book (Other academic)
  • 264.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Jordens Resurser1992In: Miljö från A till Ö, Höganäs: Bra Böckers Förlag , 1992Chapter in book (Other academic)
  • 265.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Miljö för bärkraftighet- perspektiv på naturresurser, deras begränsningar och deras roll i samhället1993Book (Refereed)
    Abstract [sv]

    Människans belastning av den tidigare till synes oändligt generösa naturen har blivit för stor. Dagens industriella samhällen är inte långsiktigt förenliga med sin naturresursbas. Nuvarande naturresursanvändning kan inte fortgå ens tills dagens spädbarn uppnår pensionsålder. Därför måste mänskligheten slå in på en väg som leder till bärkraftighet (sustainability). Detta innebär att de långsiktiga relationerna mellan natur och samhälle inte störs och att livsbetingelserna på jorden inte allvarligt förstörs eller rubbas. Samhället måste utvecklas inom de ramar som naturen ger.



    Bärkraftighetsidéerna utgör ett genomgående tema i boken. Tyngdpunkten ligger vid det bärkraftiga samhällets naturresursbas. Ett centralt mål är att presentera viktiga delar av den existerande kunskapen om de naturgivna begränsningarna och möjligheterna och hur man kan hantera olika slag av resurs- och miljöproblematik.



    Sverige och svenska förhållanden betonas med en tidshorisont mellan femtio och hundra år in i framtiden.



    Miljö för bärkraftighet är avsedd att vara lärobok vid universitet och tekniska högkolor men kan läsas av alla som har intresse av att vi får ett miljömässigt fungerande samhälle.

  • 266.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Moves on the Path Towards Sustainable Urban Mobility1997Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The overall aim of this paper is to present some ideas on how a sustainable urban transportation system might be realised, aiming at a realisation without major loss of transportation capacity and personal mobility in comparison with the present car-based system. Along the road, it also looks at what characterises such a system.

    In a sustainability perspective, it is not enough to consider only the tech-nical and physical aspects of a transportation systemsustainability has also social, economic, etc. dimensions. Thus, the paper compares the performance of different transportation systems in terms of some of the economic and social aspects. Here, a key point is that comparisons between different urban transport system must differentiate between different social groups. For example, the group of car users will have some particular disadvantages when they have to switch to another mode of transport for part of their mobility. Other groups may achieve large improvements in their personal mobility.

    The presentation pays particular attention to the use of a personal rapid transit system. The key features and technical characteristics of such a system will be presented. An outline is given of an implementation study being performed for the city of Leipzig, Germany, as a back-casting scenario futures study.

    Sustainability is closely associated with the issues of efficiency and sufficiency of natural resource use. Some essential aspects of this use can be described in terms of energy and material use. Therefore, some results of comparative studies of the energy and material balances of different urban transit systems are presented. These studies show that a personal rapid transit system can perform very well in this respect and thus is a strong alternative for sustainable cities.

  • 267.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Multidisciplinary Modelling in Environmental Science'Concepts & Examples1995Other (Other (popular science, discussion, etc.))
  • 268.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Naturwissenschaftliche Perspektiven der Ressourcennutzung1995Other (Other (popular science, discussion, etc.))
  • 269.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Optimal Development with Flow-Based Production1986In: Resources and Energy, 8Article in journal (Refereed)
  • 270.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Recycling of matter: A response1994In: Ecological Economics 9Article in journal (Other academic)
  • 271.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Some Lacunae in Thermodynamics1995Conference paper (Other (popular science, discussion, etc.))
  • 272.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Stakeholder Approaches to Intertemporal Valuation1999Chapter in book (Other academic)
  • 273.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Statistical Mechanics of Solar Energy Conversion1999In: S. Sieniutycz and A. De Vos (eds): Thermodynamics of Energy Conversion and Transport, Berlin: Springer-Verlag , 1999Chapter in book (Other academic)
    Abstract [en]

    The chapter deals with the general class of processes in which solar energy is absorbed and in which the absorbed energy is converted in multistage processes until it eventually is in a storable form. Several such processes are discussed, as well as the difficulties of modelling the processes in the framework of statistical mechanics. The description pays special attention to loss mechanisms, including the temporal aspects. Possibilities and limits for optimisation, arising both from absolute limits and from irreducible losses, are also discussed.

    Furthermore, the connection between statistical mechanics and information theory is analysed in the context of solar energy conversion. In this context, the usefulness of the exergy concept as an efficiency measure in the analysis of solar energy conversion processes is discussed. The results for the exergy of general incoherent photon exergy as well as for a more general kind of radiation field are reviewed.

    The conversion of black-body radiation, in the form of free photons within a certain volume, is used as a benchmark case. Several problems with this widely used model are described.

    It is clear that the actual achievable exergetic efficiency is in some cases considerably less than for the ideal benchmark case and also that the difference is not quantifiable with the existing models

  • 274.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Teaching Basic Thermodynamics for Energy Efficiency: A Digest of the Theoretical Basis of the Exergy Concept1993Conference paper (Refereed)
    Abstract [en]

    Exergy is a general measure of the maximal work yield of a system, applicable to general processes involving interactions, either internally or with other systems, as well as constraints. Exergy is a key thermodynamical concept in many methods for the improvement of energy efficiency in technical as well as societal systems; it is, e.g., the basis for the idea of second law efficiency. It therefore plays a significant rôle in the transformation to the energy efficient society based on renewable energy sources. Although exergy is a fundamental quantity in the theory of conversions of matter and energy, it is often inadequately treated in thermodynamics text-books. This paper describes some of those key features of exergy as a thermodynamic concept that are rarely included in courses on thermodynamics, with examples of derivations of exergy formulas in general as well as in some special cases. It also describes the rôle of exergy in a physical world view, in particular the origin of exergy.

    Many thermodynamic processes in nature involve not only simple conversion of energy and materials but also formation or breakdown of structure. Some kinds of structure formation or breakdown can be conveniently described in information theory terms. Information theory, dealing with information as a quantitative concept, was from the beginning close to physical theory, with entropy as a common concept. Information theory is closely tied to statistical mechanics, the microscopic theory of thermodynamics. To elucidate and demarcate the general scope of the exergy concept, I describe how the essentially physical quantities work and exergy can be tied to information-theoretical quantities.

  • 275.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Thermodynamics and Economics1990In: S. Sieniutycz & P.Salamon, eds., Finite-Time Thermodynamics and Thermoeconomics, Advances in Thermodynamics volume 4, Bristol: Taylor & Francis , 1990Chapter in book (Other academic)
  • 276.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Towards a Theoretical Basis for Applied Ecological Economics1994Conference paper (Refereed)
    Abstract [en]

    The paper deals with the planning/public policy instruments sustainability indicators, standards and criteria, which aim at evaluating whether, in which sense and to what extent the evolution of societal and natural systems leads towards sustainability.

    Traditionally, environmental quality indicators are conceived as numerical values of the state or the development of specific biotic or abiotic levels or flows, often expressed in biological, physical or chemical terms. The ecological bioindicators represent a well-known example. However, environmental quality can also be viewed in a perspective encompassing social science aspects as well as the natural science ones. This has led to the idea of sustainability criteria, which are concepts embracing social and natural aspects of sustainability.

    The basic idea of sustainability criteria is to make the implicit assumptions underlying indicators and standards explicit and thereby amenable to scientific analysis. They should be used in combination with indicators and standards. The formulation of the criteria directs the choice and definition of the indicators. The criteria have to be based on scarcity concepts and associated natural limits to sustainable development. The properties and implications of some such limits are discussed.

    The paper embraces both the theoretical basis and opportunities and obstacles for the application of sustainability criteria

  • 277.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Unresolved issues for the use of an energy numeraire in LCA2007Conference paper (Refereed)
    Abstract [en]

    The methodological framework of LCA has a number of well-known problems and limitations. This has generated a lot of scientific efforts to eliminate or alleviate these. This paper can be seen as one contribution to these efforts, with a particular focus on energy issues in LCA. It has been concluded that a future comprehensive methodological framework for LCA must include a number of principles for comparison and aggregation of different energy forms or of their environmental impacts. In economics, the central concept of value is encapsulated in the term numeraire. This signifies the function of money as a common, universal currency, a measure of value or a unit of account. A numeraire can be used both for comparison and aggregation. A basic requisite for a numeraire is generality. It is here discussed whether it is possible to define an energy numeraire for use in LCA methods, in particular when the LCA is to be used for specific kinds of optimisation. I conclude that the exergy concept needs quite a lot of further theoretical development before it can be included in LCA methodology. Attempts to do so at the present stage would be premature and lead to disappointment and confusion

  • 278.
    Månsson, Bengt
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Andresen, B.
    The Optimal Temperature Profile for an Ammonia Reactor1986In: I&EC Process Design and Development 24Article in journal (Refereed)
  • 279.
    Månsson, Bengt
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Grossmann, W.-D.
    Beyond Sustainability Indicators1994Conference paper (Refereed)
    Abstract [en]

    It is generally recognized that the operationalization of sustainability is still very much in its infancy; the strategies to be employed need much further development. There is now a major effort to develop instruments for environmental policies that lead towards the goal of a sustainable society. As a result, there exists a tool kit that contains a fair number of at least somewhat useful devices. Within this tool kit, this paper looks at the planning/public policy tools indicators, standards and strategic criteria; these are being developed to be used to evaluate whether, in which sense and to what extent particular societal developments lead towards that goal.

    These tools should be seen in relation to one of the critical issues of sustainability policy, the development of monitoring systems that reflect environmental resources (Unemo 1992). In several cases, they are devised as an attempt to solve problems that the conventional framework of environmental economics cannot give a satisfactory treatment.

    Apart from a brief presentation of these tools, the paper also contains a discussion on the application of sustainability criteria. The main emphasis is on the different rôles of indicators and criteria, arising from the inherent limitations of environmental and other indicators.

  • 280.
    Månsson, Bengt
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Lindgren, K.
    Thermodynamics, Information and Structure1990In: S. Sieniutycz & P. Salamon, eds., Nonequilibrium Thermodynamics and Extremum Principles, Advances in Thermodynamics volume 3, Bristol: Taylor & Francis , 1990Chapter in book (Other academic)
  • 281.
    Månsson, Bengt
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    McGlade, J.M.
    Ecology, Thermodynamics and H.T. Odum's Conjectures1993In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 93, no 4, p. 582-596Article in journal (Refereed)
    Abstract [en]

    The central rôle of energy in all life processes has led to the development of numerous hypotheses, conjectures and theories on the relationships between thermodynamics and ecological processes. In this paper we examine the theoretical and empirical support for these developments, and in particular for the widely published set of thermodynamic conjectures developed by H.T. Odum, in which the maximum power principle is put forward as a generic feature of evolution in ecosystems. Although widely used, we argue that many of the ecological studies that have adopted the ideas encapsulated in Odums work, have done so without being aware of some of the fundamental problems underlying this approach. We discuss alternative ways in which a general available-work concept could be constructed for use as a numeraire in an energy-centered ecological theory or paradigm. In so doing, we examine what is meant by material accessibility and energy stocks and flows with respect to traditional food web and food chain theories, and relate these to results from the evolutionary dynamics of ecosystems. We conclude that the various forms and uses of energy bound up in essential ecosystem processes present a formidable obstacle to obtaining an operational definition of a general, aggregated available-work concept, a prerequisite for the systems approach of Odum and others. We also show that the prototypical derivations of the maximum power principle, and its interpretation, are contradicted on many scales both by empirical data and models, thereby invalidating the maximum power principle as a general principle of ecological evolution. The conclusions point to the fundamental problem of trying to describe ecosystems in a framework which has a one-dimensional currency.

  • 282.
    Månsson, Bengt
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Rehnström, Carina
    Classification of energy-related problems for LCA methodologya case study based approach2007Conference paper (Refereed)
    Abstract [en]

    In the current LCA literature, energy issues are very cursorily treated, if at all. Papers in the area tend to be restricted in scope to specific product categories or specific industries and do not primarily aim at formulating a theoretical foundation for energy in LCA methodology. This paper can be regarded as a contribution to the development of such a foundation. We show how the energy-related problems can be classified into twelve types. Some of these are well-known and adequate solutions exist, some needs further work. Note that we do not claim that it is always necessary to include an energy perspective in LCA, but we do claim that there are certain kinds of contexts or circumstances that make it essential. For the latter cases, a well-defined and scientifically well-founded methodology should be developed. We show here that such a development has to overcome a number of difficult obstacles.

    In LCA methods, energy has hitherto been treated so that i) some kinds of energy-related environmental effects have been left out of the analysis; ii) the LCA indices give the wrong signals with regard to energy savings or efficiency improvement potentials. Obviously, the problems caused by such procedures are most severe for energy-intensive industries and in particular for the energy sector.

    We discuss two major kinds of dangers with not using a theoretically well-founded energy concept and methodology in an LCA. First, an element of arbitrariness is introduced, so that, e.g., the final value of an LCA index may be manipulated. Second, and for process and product development more severe, the LCA can lead to sub-optimal changes in the products and production processes

  • 283.
    Mårtensson, Pär
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Gatubelysning i bebyggelse utan fast elnät i Ghana: Kan en anläggning för gatubelysning drivas av solceller med bränsleceller som ackumulator, i ett slutet system?2013Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Abstract

    There are rural areas in Ghana which are off-grid but where there is a need for street lighting.

    Street lighting facilities in such areas typically store electrical power in lead-acid batteries.

    The goal of this thesis is to construct a facility where fuel cells and hydrogen accumulation

    replace lead-acid batteries.

    The construction consists of a solar cell which transmits DC power to an electrolyzer which in

    turn produces hydrogen and oxygen. The gases accumulate in the container until nightfall

    when it starts providing DC power to street lighting via a fuel cell. The street lights can

    operate between 5 - 10 hours per day, depending on the power of the lamp.

    Besides providing street lighting the device may also be used for other purposes such as

    indoor lighting, charging of mobile phones etc. This means that, in addition to the basic

    purpose of providing electrical power to the street lights, other co-benefits of social

    significance can be achieved. The device is designed not to create any harmful emissions

    during operation, thus being environmentally sustainable. Further research on the device may

    in a second step entail: Construction of a prototype on a smaller scale, where calculations and

    function are tested. If it turns out well, a third step can begin: To build a full scale plant to be

    tested on site in Ghana.

  • 284. Mörtberg, Ulla
    et al.
    Deal, Brian
    Cvetkovic, Vladimir
    Balfors, Berit
    Azcarate, Juan
    Haas, Jan
    Pang, Xi
    Integrating ecosystem services in urban energy trajectories2015Other (Other academic)
  • 285.
    Naqvi, Muhammad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). Department of Energy, Building, and Environment, Mälardalen University, Sweden.
    Dahlquist, E.
    Department of Energy, Building, and Environment, Mälardalen University, Sweden.
    Yan, J.
    Department of Energy, Building, and Environment, Mälardalen University, Sweden & Department of Chemical Engineering, Royal Institute of Technology (KTH), Sweden.
    Naqvi, S. R.
    School of Chemical & Materials Engineering, NUST, Pakistan.
    Nizami, A. S.
    Center of Excellence in Environmental Studies, King Abdulaziz University, Saudi Arabia.
    Salman, C. A.
    Department of Energy, Building, and Environment, Mälardalen University, Sweden.
    Danish, M.
    State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, ECUST, China.
    Farooq, U.
    State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, ECUST, China.
    Rehan, M.
    Center of Excellence in Environmental Studies, King Abdulaziz University, Saudi Arabia.
    Khan, Z.
    Systems Power and Energy, School of Engineering, University of Glasgow, UK.
    Qureshi, A. S.
    Institute of Biotechnology and Genetic Engineering, University of Sindh, Pakistan.
    Polygeneration system integrated with small non-wood pulp mills for substitute natural gas production2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 224, p. 636-646Article in journal (Refereed)
    Abstract [en]

    This study aims to examine the potential substitute natural gas (SNG) production by integrating black liquor gasification (BLG) island with a small wheat straw-based non-wood pulp mills (NPM), which do not employ the black liquor recovery cycle. For such integration, it is important to first build knowledge on expected improvements in an overall integrated non-wood pulp mill energy system using the key performance indicators. O2-blown circulating fluidized bed (CFB) gasification with direct causticization is integrated with a reference small NPM to evaluate the overall performance. A detailed economic analysis is performed together with a sensitivity analysis based on variations in the rate of return due to varying biomass price, total capital investment, and natural gas prices. The quantitive results showed considerable SNG production but significantly reduced electricity production. There is a substantial CO2 abatement potential combining CO2 capture and CO2 mitigation from SNG use replacing compressed natural gas (CNG) or gasoline. The economic performance through sensitivity analysis reflects significant dependency on both substitute natural gas production and natural gas market price. Furthermore, the solutions to address the challenges and barriers for the successful commercial implementation of BLG based polygeneration system at small NPMs are discussed. The system performance and discussion on the real application of integrated system presented in this article form a vital literature source for future use by large number of small non-wood pulp industries.

  • 286.
    Neldorin, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Utveckling av substratmixen vid Mosseruds biogasanläggning: Substratkartläggning och rötningsförsök i laboratorieskala2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The world’s growing need for energy together with a desire to ward off the worst consequences of global climate change has resulted in a never seen desire to invest resources in renewable energy sources. Biogas production through anaerobic digestion is one of those growing energy sources. In Sweden there are over two hundred plants that uses this biological process to break down organic substances while producing carbon dioxide and the energy-rich gas methane.

    This master’s thesis has focused on development of the mixture of different organic substances that is treated at a specific plant, namely Mosserud biogas plant. Located a couple of kilometers west of the city of Karlskoga it has good possibilities to treat material from a big geographic area. Today the plant mainly treats organic fraction of municipality solid waste, cattle manure and ley crops. The study is based partly on a survey of what substrates are accessible in the region and if they are feasible to treat at the plant in both a practical and theoretical sense. This part of the study resulted in a new potential waste amount of 6 000 tonnes per year which is almost 10 % of what the plant is built to treat. Slaughterhouse waste from Närke slakteri is one of the most promising waste fractions as it has high methane potential while the cost for transportation is relatively low. Packaged food waste from supermarkets may contribute with additional waste amounts if not the competition from waste incineration plants is too big.

    The second part of the study consisted of a laboratory scale digestion experiment at Karlstad University whose goal was to evaluate what consequences an altered substrate mixture has on methane production and process stability. Due to neglible amounts of new kinds of waste in the mapping survey no single waste could change the overall substrate mixture. Therefore a change in the original substrate mixture was made so that more food waste and less ley crop and manure are digested. This may lead to process failure due to VFA accumulation because of a higher food waste/manure-ratio (from 2 to 5).

    No accumulation of organic acids could be detected which may have resulted in a pH- drop followed by a restricted methane production. This doesn’t necessarily mean that there won’t be any problem in the full-scale biogas plant, due to a higher organic loading applied there. The methane production was 0,385 Nm3/kgVS/day and 0,352 Nm3/kgVS/day in the two substrate mixtures and the difference could be explained by a higher amount of food waste, which is the substrate with the highest methane potential, in one of the mixtures.

  • 287.
    Nilsson, Aron
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Energiutvinning från deponigas: På Holmby återvinningscentral2017Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In this study a evaluation has been conducted to whether the amount of landfill gas in the landfill at Holmby recycling station in Sunne could be used to cover the heat needed to heat up a couple of buildings nearby, how much electricity that would be produced in the process and if there would be any economic gain in doing so. The machinery used in this study is a natural gas engine, gas turbine and a gas fired boiler from Biogas Systems and a Stirling engine from Cleanergy. These have been evaluated together with a heat storage tank to see if they could produce enough heat for the buildings. The system in place today only uses a torch to dispose the gas and no energy from the gas is used. The energy in the gas should be taken care of because it could replace other energy sources that are worse for the environment. Beyond the results in this study you will have to consider the distribution of the produced heat and electricity. The main thought is that you will produce the heat needed and sell the electricity you don’t use yourself. The calculations have been conducted in Matlab and the tool Simulink. The results showed that you can produce enough heat with all the examined apparatuses, with their efficiencies and other restrictions at the same time as you could sell a fair amount of electricity by using three of them, the only exclusion is the gas fired boiler as it doesn’t produce any electricity. The gas turbine becomes very expensive due to its price and the relatively small electric efficiency. It is a possibility that you won’t make any money from a system with a gas turbine. A gas fired boiler is the recommended machinery if there is no interest in electricity production due to its ability to produce the heat needed at the same time as it is the cheapest of the tested machinery. If on the other hand there is an interest in electricity production the Stirling engine would be the recommended machinery. The Stirling engine manage the heat needed in the buildings at the same time as it produces electricity that could be sold. The reason that the Stirling motor is the preferred machinery in this case is that it is not as sensitive to the pollutions in the landfill gas as the natural gas combustion engine.

  • 288.
    Nilsson, David
    Karlstad University, Faculty of Technology and Science.
    Energieffektiv utformning av luftaren airTURBO 1012006Independent thesis Basic level (professional degree), 15 points / 22,5 hpStudent thesis
    Abstract [en]

    Eden Aquatech has developed a surface aerator called airTURBO 101. Aerators are used to oxygenate water in basins and ponds within biological wastewater treatment. AirTURBO 101 consists of a submerged impeller that creates a vortex which transports air below the surface. The impeller is surrounded by a plastic cylinder. In the present design of the aerator, incoming water penetrates the cylinder through a circle of holes in the wall of the cylinder. This study has examined the original cylinder and an alternate design, where the cylinders where totally submerged and the water could pour over the brim. Two cylinders with submerged brim were tested. One had the same inlet area as the original cylinder and the other had a larger inlet area. These three cylinders has been tested and compared to find out which one has the highest oxygenation rate proportionately to the energy consumption.

    The following parameters were examined: the water motion inside the cylinders, energy consumption, the interface between air and water inside the cylinders and the oxygenation velocity. All experiments were carried out using scale models of airTURBO 101.

    Initial experiments showed that the vortices for all cylinders were more unstable than expected.

    The examinations of the water motion inside the cylinders showed that none of the designs could guarantee a continuous contact between the incoming water and the air.

    The energy consumption turned out to be similar for the different cylinders. The submerged cylinder with large inlet had slightly lower energy consumption than the other.

    The interface between water and air could not be calculated due to shortages in the specially developed mathematical formula. A visual depiction was not possible since the vortices were too unstable.

    When measuring the velocity of oxygenation the different cylinders had similar results at a constant power. When the power was doubled a considerable increase of velocity occurred. Also during these experiments the submerged cylinder with large inlet turned out to be slightly better than the other.

    One conclusion is that the submerged cylinder with large inlet is somewhat better than the other cylinders.

    Another conclusion is that the main part of the aeration does not occur in the interface between water and air in the vortex, but rather in the interface created by the impeller itself. Further development of this aerator should focus on the design of the impeller. The air bubbles created in the impeller should be as small as possible.

  • 289.
    Nilsson, Jessica
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Fjärranalys av skogsskador efter stormen Gudrun: Skogens återhämtning efter den värsta stormen i modern tid2017Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    On January 8th, 2005 one of the most devastating storms in Sweden’s history occurred, where hundreds of thousands became powerless and seven people lost their lives. The storm Gudrun hit central Götaland worst and nearly nine years’ professional felling of forests was estimated to have fallen in some areas. Previous studies of the storm were carried out on behalf of the Swedish Forest Agency, where the results show that the proportion of windthrown forest area was 11 % in the worst affected municipality of Ljungby. About 80 % of all damaged forests were spruce, 18 % were pine and 2 % were deciduous.                       

    The aim of this thesis is to investigate the amount of windthrown forest after the storm Gudrun through analysis of satellite remote sensing data. The proportion of windthrown coniferous and deciduous forest was calculated and the results were compared to the reports written on behalf of the Swedish Forest Agency. Furthermore, the proportion of reforested areas in 2016 was calculated. A change analysis based on satellite data from Landsat 5 from 2004 and 2005 was performed which included a forest mask created by supervised MLC classification. The forest mask was used to exclude uninteresting areas in the analyses. The result was then used for the analysis of the proportion of windthrown coniferous and deciduous forest and for the analysis of reforested areas in 2016. In the latter, a forest mask based on Landsat 8 data was used.

    The results from the analyses show that about 15.8 % of the forest was windthrown, of which 78 % were coniferous and 13 % were deciduous forest. By 2016, 25% of the windthrown areas had been reforested. The accuracy of the results is generally high, but despite this, it substantially differs from the results of earlier studies. The reason for this could be differences in satellite images and programs and additional error sources in conjunction with the analyses.

  • 290.
    Nilsson, Lars
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Hauri, Nils
    Gustavsson, Christer
    Renström, Roger
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Consequences of a dew point increase in tissue drying2006Conference paper (Refereed)
  • 291.
    Nordlund, Anna
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Potential for Solar Water Heating in Kosovo2010Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To achieve a development that will be sustainable in the long run, one has to care for the economic, environmental and social aspects. One of these cannot stand-alone but is incorporated in a type of symbiosis. Kosovo is a state that after suffering a long-drawn war in the 90’s have had problems with all of these keystones. There is a high level of unemployment as well as negative impacts on the environment including poor waste management and heavy emissions of carbon and nitrogen oxides. The objective of the thesis was to contribute to Kosovo’s work towards sustainable development, focusing on solar heated tap water. Since 90 percent of the hot water is produced with lignite-based electricity whilst there is a steady supply of sunny days throughout the year.

     

    In this project the potential for solar heated tap water in Dragash/Dragaš in southern Kosovo was investigated. The availability of sun was decided by determining the incoming solar radiation for different inclinations and cardinal directions. This was then applied to an existing SWH system at the municipal hospital and two hypothetical SWH systems. The annual energy benefit for the current system, which currently is not in service, was determined and the system was investigated to offer improvements. Two other public buildings were chosen for the hypothetical systems and solar collector and storage tank sizes were chosen based on the hot water demand of the buildings. After which the possible energy benefit was computed, as well as the environmental and economic effects. The social and economic potential for an increased use of SWH systems was concluded by interviews and questionnaires with the ministry and municipal politicians as well as citizens of Dragash/Dragaš.

     

    The possible energy benefit of the existing SWH system at the hospital was found to be 7.5 MWh/year. Possible improvements of the system would be an increased inclination and improved insulation for in-door piping. A school and an office were chosen as the most suitable buildings for the hypothetical systems, and the storage tanks were dimensioned to be 1,400 liters and 700 liters respectively. The collector area chosen for the school was 24 m2 and for the office 12 m2, giving a coverage of 65 percent of the annual hot water demand. The CO2 reduction for the office was more than twice as big as for the school. This is due to that the current energy source of the school is oil and the one of the office is lignite-based electricity. The pay-off time for the school and the office was six and eight years respectively.

     

    In Kosovo the energy and environmental awareness is small. But there is an interest in learning more about energy and environmental issues and alternative energy sources, such as solar energy. Although the citizens rather prioritize other environmental areas, for example improved waste management. The biggest obstacle for an increased use of SWH systems in Kosovo today, is the unreasonable high investment cost for a family with an average income. But were there better economical possibilities they would be open to SWH installations in their homes. Wherefore a proper mechanism for financing and incentives needs to be established to enable a more widespread use. An increased use would, in addition to the environmental advantages, also create job opportunities in the production phase as well as in installation and maintenance. It would also increase the standard of public buildings since all of these do not have access to hot water at this time.

  • 292.
    Nordqvist, Erik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    A pilot study on the coupling potential for a hydrokinetic turbine within the Amazon basin: - Optimization from an energy perspective2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Many people around the world still lack access to a reliable electricity grid. Supplying electricity to remote off grid areas like villages around Leticia, Colombia is often interrelated with high costs and geographical limitations. Today most of the electricity demand is met through the usage of diesel generators. The generators are easy to use and have a relatively reliable functionality. However, fuel is expensive and there are other negative aspects as fumes and sound pollution. In order to provide a cleaner, more reliable and cost efficient alternative the company Jabe Energy AB has in cooperation with the volunteer organization Ankarstiftelsen developed a new type of hydrokinetic turbine (slow moving none damming turbine).

    Previous studies have shown that there is potential for hydrokinetic turbines to increase their power output simply by their relative placement (coupling potential). That is, it might be possible to extrude more power from a system where two hydrokinetic turbines are placed in a close relation rather than being completely separated.

    Since the turbine investigated is newly developed there have been no previous studies regarding its specific coupling potential. To investigate this potential given the conditions in the Amazon basin, a field study is conducted where measurements on water velocity at different heights in the water column is collected. The data is later used as input conditions for a turbine model developed in the program COMSOL.

    The aim is to use simulations in order to determine whether a turbine is sensitive for its relative placement to a former (coupling potential) and furthermore to investigate a possible optimal turbine coupling position.

    The results will show that the turbine is coupling sensitive and that there exists more advantageous placements. Comparing the best and worst case of the coupling study displays an 11.87% difference in possible energy output. The conclusion is that further empirical studies are necessary in order to validate the results. Finally a suggestion on how these studies should be conducted is presented and discussed.

  • 293.
    Nordqvist, Sandra
    et al.
    Karlstad University, Faculty of Technology and Science.
    Öhman, Susanne
    Karlstad University, Faculty of Technology and Science.
    Vindkraft- En klass för sig2009Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
  • 294.
    Nordén, Joakim
    Karlstad University, Faculty of Technology and Science.
    Energistudie Säffle Verkstadsbolag AB: Kartläggning av elanvändningen med förslag på energieffektiviserande åtgärder2012Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    I detta projekt kartläggs elanvändningen vid Säffle Verkstadsbolag AB. Projektet undersöker även olika effektiviserande elåtgärder, samt effektiviserande värmeåtgärder på kontorslokalen. De frågor som projektet svarar på är:

    1. Hur ser företagets elanvändning ut i dagsläget?

    2. Hur stor energibesparing kan uppnås genom de undersökta effektiviseringsåtgärderna på elanvändningen?

    3. Hur stor energibesparing kan uppnås genom de undersökta effektiviseringsåtgärderna på kontoret i form av värme?

    4. Hur påverkas CO2-utsläppen genom de utförda energibesparingarna?

    Syftet med arbetet är att företaget ska få en inblick i vart den köpta elen används och vilka effektiviseringar det kan vara värt att satsa på ur energi- och miljösynpunkt. Den del av arbetet som undersöker potentiella effektiviseringsåtgärder på värmen i kontoret, gjordes också på grund av att det fanns ett problem med för låga temperaturer i lokalen vintertid.

    Metoden som har använts vid elkartläggningen är studier av timvärden över energianvändningen, mätningar av effekt och inventering av märkeffekter på undersökta områden. Förslag till el- och värmeeffektiviserande åtgärder har gjorts utifrån vetskap om hur företagets olika system fungerar, frågor och diskussioner med personal, rundvandringar på företaget och framförallt litteraturstudier. Vissa av åtgärderna identifierades på grund av den inblicken som erhölls under den spenderade tiden på företaget. För att beräkna besparingen som de olika åtgärderna genererar har energianvändningen före och efter jämförts. Hur CO2-utsläppen påverkas har beräknats med hjälp av data från utsläppen vid tillverkning av elen och värmen.

    Elkartläggningen resulterade i att 7 % av elanvändningen används till ventilations-el,16 % till belysnings-el, 25 % till bas-el, 2 % till kontors-el, 26 % till verkstads-el och 24 % till övrig el.

    De eleffektiviserande åtgärder som undersökts är byte till LED-belysning, borttagning av elelement, annan kylning av server, annan uppvärmning i verkstaden, tryckluftstätning och styrning av ventilation. Utöver detta har också driftstiden på tryckluftskompressorerna, ventilationsflöden och SFP-värden undersökts. Åtgärderna som undersökts på värmen i kontorslokalen är förbättringar av klimatskalet samt byte av ventilationssystem.

    Med de besparingsåtgärderna som undersökts finns det potential att spara ca 57 000 kWh el/år och ca 40 000-45 000 kWh värme/år beroende på vilka åtgärder som väljs. Detta motsvarar en besparing på ca 57 000 kg CO2/år på grund av elbesparingarna och ca 1200 kg CO2/år på grund av värmebesparingarna.

  • 295. Nyberg, Lars
    et al.
    Almered Olsson, Gunilla
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Bladh, Gabriel
    Skogslandskap för hållbar utveckling2004Chapter in book (Other academic)
  • 296.
    Nyman, Elin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    En frånluftsvärmepumps inverkan på ett fjärrvärmesystem: Jämförelse mellan byggnad med fjärrvärme och byggnad med kombination av frånluftsvärmepump och fjärrvärme2016Independent thesis Basic level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    It has become more and more common to combine district heating with an exhaust air heat pump in Sweden, especially in multi-family dwellings. One reason that the exhaust air heat pumps are becoming more common is Boverket's rules on the amount of energy a dwelling can purchase, which today favors the exhaust air heat pumps. Another reason is that property owners want to reduce their energy costs by taking advantage of the energy from the exhaust air in the house, that otherwise would be lost.

    The work has been performed on behalf of WSP Process in Karlstad. The aim has been to provide a better understanding of how the connection of an exhaust air heat pump affects an existing district heating system in a multi-family dwelling in the municipality of Karlstad. This is seen from both the property owner's and the district heating supplier's perspective, focusing on energy and economy.

    A comparison has been made between two, in terms of size and energy use, equivalent multi-family dwellings in the municipality of Karlstad. One dwelling has exhaust air heat pump combined with district heating as heat source, while the other dwelling is heated only by district heating. Data for the two buildings have been used together with calculations to produce the results.

    It turned out that with an exhaust air heat pump installed, 49 MWh per year was saved in energy use. On an annual basis the two multi-family dwellings today uses just above and just below 200 MWh of heating energy each, which makes 49 MWh a huge energy save.

    The property owner's energy costs are 16 % higher for the dwelling with exhaust air heat pump and district heating in combination compared to the dwelling with only district heating, calculated over a period of 15 years.

    For the district heating supplier, the combination of the exhaust air heat pump and district heating raises the return temperature significantly (cooling deteriorates) in the district heating network. This is partly because the exhaust air heat pump is connected to the radiator system's return-side. To avoid the bad cooling, the exhaust air heat pump should instead be installed on the radiator system's forward conduit, which is a proposal that has been described in the report.

    The efficiency of heat transfer is better for the dwelling only supplied by district heating; 16,3 m3 heating water is pumped per MWh of sold district heating. This is compared to 19,1 m3 per MWh for the home with exhaust air heat pump and district heating in combination. This means that it is more profitable for the district heating supplier to sell district heat to the home supplied only by district heating that has higher heat transfer efficiency.

  • 297. Nørh Glud, Ronnie
    et al.
    Gundersen, Jens Kristian
    Holby, Ola
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Benthic in situ respirationin the upwelling area off central Chile1999In: Mar. Ecol. Prog. Ser. 186: 9-18Article in journal (Refereed)
  • 298. Nørh Glud, Ronnie
    et al.
    Holby, Ola
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Hoffman, Friedrike
    Canfield, Don
    Benthic mineralisation and exchange in arctic sediments (Svalbard, Norway)1998In: Mar. Ecol. Prog. Ser. 173: 237-251Article in journal (Refereed)
  • 299.
    Olin, Malin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Estimation of base level for an aquifer from recession rates of groundwater levels1995In: Hydrogeology journal, v.3, no 2 pp 40-51Article in journal (Refereed)
  • 300.
    Olin, Malin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Evaluating geological and recharge parameters for a linear aquifer in southern Sweden using groundwater level variations1992In: 20th Nordic Geological Winter meeting, 7-10 January, Reykjavik 1992Article in journal (Refereed)
3456789 251 - 300 of 417
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf