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  • 1. Abdel-Rehim, M.
    et al.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Bielenstein, M.
    Arvidsson, T.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Evaluation of Solid-Phase microextraction (SPME) for Study of the protein Binding in Human Plasma Samples,2000In: J. Chromatogr. Sci., 38 (2000) 458-464Article in journal (Refereed)
  • 2.
    Almlöf Ambjörnsson, Heléne
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Mercerization and Enzymatic Pretreatment of Cellulose in Dissolving Pulps2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the preparation of chemically and/or enzymatically modified cellulose. This modification can be either irreversible or reversible. Irreversible modification is used to prepare cellulose derivatives as end products, whereas reversible modification is used to enhance solubility in the preparation of regenerated cellulose.

    The irreversible modification studied here was the preparation of carboxymethyl cellulose (CMC) using extended mercerization of a spruce dissolving pulp. More specifically the parameters studied were the effect of mercerization at different proportions of cellulose I and II in the dissolving pulp, the concentration of alkali, the temperature and the reaction time. The parameters evaluated were the degree of substitution, the filterability and the amount of gel obtained when the resulting CMC was dissolved in water. Molecular structures of CMC and its gel fractions were analysed by using NIR FT Raman spectroscopy. It was found that the alkali concentration in the mercerization stage had an extensive influence on the subsequent etherification reaction. FT Raman spectra of CMC samples and their gel fractions prepared with low NaOH concentrations (9%) in the mercerization stage indicated an incomplete transformation of cellulose to Na-cellulose before carboxymethylation to CMC. Low average DS values of the CMC, i.e. between 0.42 and 0.50 were obtained. Such CMC dissolved in water resulted in very thick and semi solid gum-like gels, probably due to an uneven distribution of substituents along the cellulose backbone. FT Raman spectra of CMC samples and their gel fractions mercerized at higher alkaline concentration, i.e. 18.25 and 27.5% in the mercerization stage, indicated on the other hand a complete transformation of cellulose to Na-cellulose before carboxymethylation to CMC. Higher average DS values of the CMC, i.e. between 0.88 and 1.05 were therefore obtained. When dissolved in water such CMC caused gel formation especially when prepared from dissolving pulp with a high fraction of cellulose II.

    The reversible modification studied was the dissolution of cellulose in NaOH/ZnO. Here the effect of enzyme pretreatment was investigated by using two mono-component enzymes; namely xylanase and endoglucanase, used in consecutive stages. It was found that although the crystallinity and the specific surface area of the dissolving pulp sustained minimal change during the enzymatic treatment; the solubility of pulp increased in a NaOH/ZnO solution from 29% for untreated pulp up to 81% for enzymatic pretreated pulp.

  • 3.
    Almlöf Ambjörnsson, Heléne
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Östberg, Linda
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Schenzel, Karla
    Martin Luther University Halle-Wittenberg, Department of Natural Scinence III, Institute of Agriculture and Nutritional Science.
    Larsson, Per Tomas
    Innventia AB, Fibre and Material Science Business area Biorefining, Stockholm.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Enzyme pretreatment of dissolving pulp as a way to improve the following dissolution in NaOH/ZnO2014In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 68, no 4, 385-391 p.Article in journal (Refereed)
  • 4.
    Almssad, Asaad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Betongkonstruktion2015Book (Other academic)
    Abstract [sv]

    Betongkonstruktion behandlar dimensionering och utförande av betongkonstruktioner enligt Eurocode 2. Boken består av en teoridel som innefattar:• Böjning och böjning med normalkraft• Pelare och väggar• Genomstansning• Plattor• Beräkning i bruksgränstillståndet

    Bokens konkreta pedagogiska värden är, utöver ett stort antal övnings­exempel med lösningar och svar, ett avsnitt med utvecklande övningsuppgifter som studenterna kan lösa själva.Svaren till dessa uppgifter finns i boken och utförliga lösningsförslag finns att tillgå på webben, www.studentlitteratur.se/39041.

  • 5.
    Almssad, Asaad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Almusaed, Amjad
    Archcrea Institute.
    Bio-Ecological Sustainable Windows2005In: The International Conference Sustainable Building 2005 SB05, Tokyo: SB05Tokyo National Conference Board , 2005, 31-34 p.Conference paper (Refereed)
    Abstract [en]

    Window is a vital part of any house they permit natural light into the house as long as views and fresh air. In the same time we can consider that the window is an extremely influential factor in climatic design, as the weakest climatic element of the building envelope. Well designed and protected windows improve comfort year round and reduce the need for heating in winter and cooling in summer. Aesthetics appearance, view, and optical performance, are usually quite important to the occupant. In reality, the serious lighting designer cannot take any notice of the energy implications of window choices. New technologies help to resolve the historic problem of the transaction between windows that reflect unwanted solar gains in the summer and those that admit a maximum quantity of useful light. Well-designed windows and shading devices allow solar heat gain in winter and shade and ventilation in summer while providing enough day lighting. Solar gain achieved by heaving 60% of the building’s windows orientated correctly can reduce the heating load of  house by _22%.In houses, low solar heat gain coefficient glazing should be used on east and west orientations, while high glazing should be used when passive solar and day lighting are being utilized.

    Today’s window technologies can replace more primitive strategies for shielding interior spaces from unwanted sunlight, such as tinted windows and curtains.

  • 6.
    Almssad, Asaad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Almusaed, Amjad
    Archcrea Institute.
    Efficient daylighting approach by means of light-shelve device adequate for habitat program in Aarhus City2014In: International Journal of Smart Grid and Clean Energy, ISSN 2315-4462, Vol. 3, no 4, 441-453 p.Article in journal (Refereed)
    Abstract [en]

    The concepts of light shelves consist of windows that have face towards the sun, which receive a vast quantity of energy that could be used for healthy day lighting. This paper debates a main assessment, investigates the optimization of daylight requirement by means of light shelves system. An experimental test was carried out assessing the measurements and lighting simulations of a model of a building in order to elucidate the characteristics of indoor lighting. Light shelf is an architectural element that permits daylight to enter deep into a building. It constitutes an optimal solution for an incorrect building orientation and less sunny days. The essential objective of this study is to highlight the vital role of light shelves in residential buildings in northern Europa where the requirement is to improve the daylight in the interior functional spaces. The main objects of this paper are to investigate the effect of daylight in the interior functional spaces using light shelves, the effect of natural light diffusion in interior space in the period of low daylight season, and glare effect in this field. This paper investigates a procedure for analysing the daylight performance using software habitat function

  • 7.
    Almssad, Asaad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Almusaed, Amjad
    Albasrah University, Albasrah, Iraq.
    Environmental reply to vernacular habitat conformation from a vast areas of Scandinavia2015In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 48, 825-834 p.Article in journal (Refereed)
    Abstract [en]

    There are many original ideas and useful system inputs embedded in the building of human settlements in Scandinavian regions, where the landscape and habitat are strongly interconnected. A cold climate and strong winds are the most prominent risks that affect habitats. The Longhouse is the foremost traditional habitat in the Scandinavian region, dating back to the Iron Age, 2000 BC. This study examines the influence of climate on the conformation of habitats. Climate had a solid impact on the conceptions of habitat form and internal space. Wind and extreme temperatures had firming consequences on the housing arrangements, layouts, orientations, and building materials used in the construction process. Habitats from this region were located in an optimal arrangement, and the south orientation was used effectively. This investigation will provide an evaluative interpretation and analysis of the real facts of vernacular habitats in the context of energy efficiency and ecological concepts, considering human settlement patterns, architectural creation and building material uses. (C) 2015 Elsevier Ltd. All rights reserved.

  • 8.
    Almssad, Asaad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Almusaed, Amjad
    Archcrea Institute.
    Green housing: The optimal Solution To Combat The Negative Effects Of Global Climatechange2010In: 3rd International Conference Palenc 2010 jointly organised with EPIC 2010 & 1st Cool Roofs Conference, University of Athens, Greece , 2010Conference paper (Refereed)
    Abstract [en]

    No Architectural concept is complete without green areas. The vital mission of biophilic architecture is to revised conceptualization of architecture in response to a myriad of contemporary concerns about the effects of human activity. Our earth is warming more rapidly than it has in the past according to the research of scientists. The green building of biophilic architecture combines the interests of sustainability, environmental consciousness, green areas of the large nature, and organic approaches to evolve design solutions from these requirements and from the characteristics of the site, its neighborhood context, and the local microclimate and topography. The biophilic concept provides us with the opportunity to reach extremely low levels of energy consumption by employing high quality, cost-efficient measures to general architectural components - such measures are in turn off advantage to the ecology and economy sector. Our essential task of this research is to make of the green covering a human strategy in urban and architectural manner and to be a human culture with helping of local governments; we can acquire the competent legislation, which protect our life and environment.

  • 9.
    Almssad, Asaad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Almusaed, Amjad
    Archcrea Institute.
    Kalil Almusaed, Zaki
    Heat Island Effects Upon The Human Life On The City Of Basrah2007In: Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century: 2nd PALENC Conference 28th AIVC Conference / [ed] M. Santamouris, P. Wouters, Crete island: University of Athens , 2007, 45-47 p.Conference paper (Refereed)
    Abstract [en]

    After the terrible consequence of the Iraq –Iran war and recently USA attack over Iraq the urban green covering disappeared from large areas of the city, beside the extension of the building over the green areas. The negative effects of this phenomenon over human’s thermal comfort become more perceptive. Today we can observe clearly the negative effect of urban heat island in the center of Basra city, precisely in physical frameworks of the city; we can observe a typical phenomenon with a large negative effect for the period of summer heating that is a natural thermodynamic phenomenon. In the surfaces of physical framework, in the core of day between 12-15 pm, the sun is shining perpendicular above the earth surfaces (framework physic). Consequently the temperature on the earth surfaces increases surprisingly up to 60 ºC. Therefore there occurs a difference of temperature between the earth surfaces and cosmos space which conduce to generate a gigantic colonization of air from the earth surface to cosmos space, such resultants of this phenomenon is no air zones and under pressure on earth surfaces, with the intention of making a nasal bleeding, which seeking for a medical intervention aide.

  • 10.
    Almusaed, Amjad
    et al.
    Archcrea Institute.
    Almssad, Asaad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Bioclimatic Interpretation Over Vernacular Houses From Historical city Basrah.2006In: PLEA 2006: 23rd International Conference on Passive and Low Energy Architecture., Geneve: Universite de Geneve , 2006, 87-91 p.Conference paper (Refereed)
    Abstract [en]

    Basrah’s climate is hot, dry summer, mild to cold winter, and a pleasant spring and fall. The old builders from this region putted a big effort to create passive bioclimatic houses that corresponds the negative effects Basrah’s macroclimate. The courtyard is the central and dominant space in the house plan with a direct access to the living spaces. Houses from the city are compact with interior courtyard; the streets are sinuous and pass through houses volumes. The shady interior courtyard has the effect that the rooms do not communicate directly with the overheated air outside, but through intermediate buffer spaces. In the mean time between courtyard and street at least a wall or a building is always interposed. The House plan had an endomorphic form, (open tree form). The volumes were concept to create shadow which helps to move the air by natural movement to the deep superior side, that can be achieve through special holes. The architectural elements are strongly decorated, reproducing special typologies and traditional houses. Open spaces, covered by large roofs, are interesting due to the mix of diffuse light and shade that are an essential aesthetic factor in these buildings.

  • 11. Almusaed, Amjad
    et al.
    Almusad, Asaad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Natural Lighting Efficiency By Means of Sun- Skylight-Tubes2014In: International Journal of Engineering and Advanced Technology, ISSN 2249-8958, Vol. 3, no 3, 16-20 p.Article in journal (Refereed)
    Abstract [en]

    The notion of comfort a luminous ambience refers to the distribution of luminance and chromatic ties on the interior envelope of a space that is one of different fields of vision for a subject within an ambience. Luminance and chromatic ties are at present not often studied as far as comfort in buildings is concerned. Sun lighting and bioclimatic concept is inseparable considerations when designing a building because of the historical and practical significance of natural lighting in architecture. Sunlight is as old as architecture itself. Human life gets sufficient sunlight, in fact, we use more of 90 % of our day indoor, for this reason, specialists are now seeing how architecture can ameliorate the indoor-outdoor links. At present, by biological and technological investigation the trend is to search backwards towards the previous philosophies and advantages of more indoor / outdoor relationship. Plus homeowners who want to have healthy home environments might want to renew the most relevant facts of technology and biology.

  • 12. Anders, Ottosson
    et al.
    Nilsson, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Berghel, Jonas
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Analogies between heat and mass transfer for estimation of air humidity2013In: Sixth Nordic Drying Conference NDC 2013, Copenhagen, Denmark, 2013Conference paper (Refereed)
  • 13.
    Andersson, Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sociala krav i byggentreprenader: En tillfällig trend eller här för att stanna?2014Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Europe has, since the economic crisis of 2007, gained increasing social segregation. The gap between rich and poor has increased and the large number of hidden statistics regarding people excluded from the labor market is greater than in many years. Social exclusion has thus taken a toll on community groups that already before the crisis had a hard time getting included. Groups such as young, elderly, immigrants and people with mental of physical disabilities. To curb this development, the European Commission have, since the 2004 directives, enabled public sector clients to, through procurement of goods, services and contracts, include measures that promote social consideration.

    Social consideration is a term that have been a part of Swedish procurement legislation since 2007, and was updated in 2010. This update meant that the meaning of this term was given greater weight and that clients were more clearly encouraged to use the term.

    The term social consideration have proven to be an unclear term, both in European tutorials and governmental investigations. Investigators describe the possibility as difficult to interpret and legally complex. To enable a smooth implementation, an open dialogue between clients and contractors have been recommended. A dialogue which, according to this study based on personal interviews, is being missing, partly or completely, in many places around central Sweden.

    The goal and purpose of this study is based on a range of issues surrounding the concept of social consideration and its impact on the public sector in Sweden. What is being done, what is wanted and why. The personal interviews where conducted with municipal housing companies and municipalities in order to reconcile the current state of the new contract term.

    These interviews clearly show that the term social consideration is known by the majority of public clients in central Sweden. However, only one out of seven interviewees have hitherto pushed through a work contract with predetermined requirements on social considerations. Notable though, is that three out of seven interviewees where in the process of publishing work contracts with the instituted social demands criterion.

    The justification for why the remaining parties did not, or where not planning to, set social standards in public work contracts was motivated mainly by the absence of knowledge in the subject. Clearer evidence and better guidance was considered a linchpin for future implementation. It was consistently put forth that social responsibility can lead to good future synergies for both society and their own company. But the design of how to set the requirement or requirements and in what stage, is something that every interviewed party had its own opinion about.

    Despite divided opinions on how and at what stage social considerations should be included in public procurement, there is a unified voice among the interviewed parties saying that the concept of social responsibility and consideration is here to stay.

  • 14. Andersson, Caisa
    et al.
    Järnström, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Water-vapour permeability of barrier dispersion coating2001Conference paper (Other (popular science, discussion, etc.))
  • 15.
    Andersson, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Torkning integrerat med kraftvärmeverk: Påverkan av energibalanser i torksystem vid integrering till kraftvärmeverk2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I Sveg finns ett pneumatiskt torksystem. Systemet har sedan 1989 torkat torv till briketter men har på senare tid torkat både trä och torv för produktion av bränsle i form av pellets och briketter. Idag består anläggningen av två symmetriska torklinjer. I torklinjerna används en värmepumpkrets för återvinning av råvaruånga. I värmepumpkretsen används en kompressor driven av inköpt elenergi. Planerna är att integrera en av linjernas nuvarande torkprocess till ett kraftvärmeverk genom installation av ångpanna med bränslet torv och således producera el istället för att köpa el. Integrationen till kraftvärmeverket ger torklinjens värmepumpkrets ett nytt utseende. Kompressorn tas bort i utvald torklinje och ersätts av två lågtrycksturbiner. Det nya utseendet av värmepumpkretsen kommer innebära ett samspel mellan torkning och kraftvärmeverk. I värmepumpkretsen används olika ångflöden beroende av vilket råvarumaterial som torkas. Därför beräknades och användes olika ångflöden beroende av olika fukthalter och inmatningar i torksystemet för att se hur el- och fjärrvärmeproduktionen i kraftvärmeverket påverkades. Samtidigt jämfördes nuvarande torksystem med torksystem integrerat med kraftvärmeverk ur ett energiperspektiv genom förändring av el, fjärrvärmeproduktion och biobränsle.

    Fjärrvärmeproduktionen i kraftvärmeverket ökade vid ångflödena 31,0 ton/h och 24,0 ton/h ”till kompressor” men på grund av större beräkningsosäkerhet bortsågs dessa. Detta gav en varierad sammanlagd fjärrvärmeproduktion av systemen mellan 23,0-23,8 MW respektive 22,0-22,5 MW vid torkning av torv respektive trä (bortseende av torvscenario 1 vid fukthalten 65 %). En fjärrvärmeproduktion i den storleken, jämfört med Svegs fjärrvärmebehov, kan sägas vara för stort. En stor problematik blir därför vad all spillvärme ska användas till, framförallt på sommaren.

    Vid integrering till kraftvärmeverk minskade ”bränsle” medan ”fjärrvärme” och ”el” ökade. Beroende av vilket råvarumaterial som torkades gav en integrering ett större resultat för ”el” men mindre ”fjärrvärme” och ”bränsle” vid torkning av trä. Därför rekommenderas torkning av trä eftersom större resultat av ”el” minskar inköpt elenergi samt mindre ”fjärrvärme” resulterar till mindre spillvärme.

    Vid beräkningarna användes Simulink, ett verktyg för grafisk lösning av differentialekvationer, som ingår i programvaran MATLAB från Mathworks. I Simulink formerades olika ekvationer i statiska beräkningsmodeller för beräkning av energibalanserna i nuvarande torksystem och torksystem integrerat med kraftvärmeverk. Energibalanserna i nuvarande torksystem undersökte svårplacerade effektförluster samt genom olika energibalanskontroller kontrollerade och bedömde trovärdigheten i beräkningsmodellen. Resultaten för energibalanskontrollerna kallades ”beräkningsosäkerhet” vilket var en av flera parametrar som framlade bevis för ett variabelberoende, känsligt, komplext och svårtydande torksystem där övriga effektförluster var svåra att placera. Ett mer korrekt resultat av nuvarande system kan därför möjligtvis uppnås vid användande av en dynamisk istället för statisk modell samt användande enbart av mätdata istället för dimensionerande värden och således göra effektförlusterna lättare att placera.

  • 16. Andersson, Niclas
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Johansson, Kristina
    Ljungqvist, Carl-Henrik
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Determining the strain to failure for constrained pulp fibres by means of single-fibre2002In: Appita Journal, Vol. vol 55 no 3Article in journal (Refereed)
  • 17. Andersson, Niclas
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Johansson, Kristina
    Ljungqvist, Carl-Henrik
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Determining the strain to failure for constrained pulp fibres by means of single-fibre fragmentation2002In: Appita Journal 55(2002)3, 224-229Article in journal (Refereed)
  • 18.
    Andersson, Niclas
    et al.
    BTG Process Solutions, Sweden.
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences. BTG Process Solutions, Sweden.
    Akhlesh, Mathur
    BTG Process Solutions, Singapore.
    Smith, Dan
    BTG Process Solutions, USA.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Measurement of Dissolved Lignin, and its Impact in Fiberline Unit Operations.2017Conference paper (Refereed)
  • 19.
    Andersson, Niclas
    et al.
    BTG Instruments AB, Saffle, Sweden..
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences. Karlstad Univ, Karlstad, Sweden..
    Biazzo, Tom
    BTG Instruments AB, Saffle, Sweden..
    Van Fleet, Rick
    BTG Instruments AB, Saffle, Sweden..
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    A new sensor and a novel control concept for optimized fiber line operation2014In: TAPPI Journal, ISSN 0734-1415, Vol. 13, no 10, 39-45 p.Article in journal (Refereed)
    Abstract [en]

    Kraft and sulfite pulp mills use several consecutive process stages for pulp production. However, usually only one key pulp parameter is used for process control and that is the lignin content in the fibers, typically expressed as the kappa number. Even so, to improve process efficiency, more variables need to be monitored. To do that, a new sensor was developed, the dissolved lignin transmitter (DLT), along with a new control concept. The DLT measures the dissolved lignin content in the pulp slurry using a unique principle based on optical measurements. The device can measure the dissolved lignin inline at low consistency and at medium consistency. The sensor has two major applications: 1) improving the efficiency in washing stages and 2) optimizing chemical charges. Results from several mill trials have shown that the contribution from dissolved lignin in the filtrate portion of the pulp is up to 30% of the total bleach load, i.e., fiber and filtrate kappa number combined into the bleach plant. Hence, chemical savings can be achieved taking this component into account compared to only measuring the washed fiber kappa number. Application: The results of this study can help mills understand how to better control the pulping stages, which might lead to significant economic savings and better pollution control.

  • 20.
    Andersson, Niclas
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Wilke, Caroline
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Biazzo, Tom
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    van Fleet, Rick
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    A new sensor and a novel control consept for optimized fiberline operationManuscript (preprint) (Other academic)
  • 21.
    Andersson, Niclas
    et al.
    BTG Instruments.
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences. BTG Instruments.
    Biazzo, Tom
    BTG Americas Inc.
    Van Fleet, Rick
    BTG Americas Inc..
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Beder-Miller, Sandra
    BTG Americas Inc..
    Is Conductivity the Best Measurement of Bleach Plant Carryover?2015In: Pulp & paper Canada, ISSN 0316-4004, 1-6 p.Article in journal (Refereed)
  • 22.
    Andersson, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    A dynamic Na/S balance of a kraft pulp mill: Modeling and simulation of a kraft pulp mill using WinGEMS2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 23.
    Andersson, Tim
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Computer Modeling of Thermodynamic Flows in Reactors for Activated Carbon Production2014Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    There's a big demand for activated carbon in Ghana, it's used for the country's mining industry as well as in a multitude of other applications. Currently all activated carbon is imported despite the fact that the country has a large supply of agricultural waste that could be used for its production. This study focuses on activated carbon production from oil palm kernel shells from the nations palm oil industry.

    Earlier research points to a set of specific conditions needed for the production. The pyrolysis process produces biochar from the biomass and the process is set to take place for 2 h at 600  °C after a initial heating of 10 °C/min. The activation process then produces the activated carbon from the biochar and is set to take place for 2 h at 850 °C with a heating rate of 11.6 °C/min.

    Two reactors are designed to meet the desired conditions. The reactors are both set up to use secondary gases from diesel burners to heat the biomass. The heating is accomplished by leading the hot gases in an enclosure around a rotating steel drum that holds the biomass. To improve the ability to control the temperature profile in the biomass two outlet pipes are set up on top of the reactor, one above the biomass inlet and one above the biomass outlet. By controlling how much gas that flows to each outlet both the heating rate and the stability of the temperature profile can be controlled. The secondary gas inlet is set up facing downwards at the transition between the heating zone (area of initial heating) and the maintaining zone (area of constant temperature).

    The two reactors are modeled the physics simulation software COMSOL Multiphysics. Reference operating parameters are established and these parameters, as well as parts of the design, are then changed to evaluate how the temperature profile in the biomass and biochar can be controlled. A goal area was set up for the profile in the biomass where it was required to maintain a temperature of between 571.5 and 628.5 °C after the initial heating to be seen as acceptable. Similarly a goal area was set for the biochar between 809 °C and 891 °C after the initial heating.

    It's found from the simulations that the initial design of the reactors work well and can be used to produce the desired temperature profiles in the biomass and biochar. Furthermore it's concluded that the initial design for the pyrolysis reactor can be improved by having the gas outlet pipe situated by the biomass inlet face downwards instead of upwards. The redesign improves the overall efficiency of the reactor by increasing the heating rate and maintained temperature.

    The evaluation of the operating parameters led to the conclusion that the secondary gas inlet temperature effects the temperature profile to a greater extent than the gas mass flow in both reactors thereby making them more energy efficient. The increase in efficiency comes with a drawback of more unstable temperature profile. If the temperature profile becomes too unstable it will include temperatures that are too high or too low to be seen as acceptable.

  • 24.
    Andreas, Svensson
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Nabrink, Robin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    GNSS-Styrning: Information för platschefer2013Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
  • 25.
    Annergren, Goran
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Process aspects for sulfite pulping2014In: Appita journal, ISSN 1038-6807, ISSN 1038-6807, Vol. 67, no 4, 270-276 p.Article in journal (Refereed)
    Abstract [en]

    Sulfite pulping of wood, with the aim of producing a paper product, can be carried out under acidic, neutral or alkaline conditions. However, if a dissolving pulp is required to be achieved, only acidic conditions may be employed. The main reason for this specific requirement for dissolving pulps is the high level of cellulose purity required. The hemicellulose content should therefore be low and hemicellulose molecules are best removed at low pH. Another difference is that in paper pulps it is the fibre properties that are of a dominant interest, while in a dissolving pulp the cellulose properties are of significant interest. However, one similarity for both paper and dissolving sulfite pulps is the risk of uncontrolled side-reactions, which can lead to severe lignin condensation reactions, and in extreme cases even to a totally black pulp. Thus, sulfite pulping is a relatively complex chemical process and an overview of the most important parameters is thus presented.

  • 26.
    Annergren, Göran
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Instability of acidic sulfite cooking of softwoods2013Other (Other academic)
  • 27. Annergren, Göran
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sulfate cooking - a commercially dominating and continously improving pulping process2014Report (Other academic)
    Abstract [en]

    Sulfite cooking was earlier the dominating pulping process but sulfate (kraft) cooking is today the most important process for the production of chemical pulps and high-yield pulps. One important reason for this development of the sulfate process is its ability to efficiently use different wood species, in particular different hardwood species. Another reason is that bleached hardwood sulfate pulps have become a strong competitor to bleached softwood sulfite pulps. The pros and cons of sulfate cooking are discussed in this report and compared with sulfite cooking.

     

  • 28. Annergren, Göran
    et al.
    Kvarnlöf, Niklas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sulfitmassa: Översikt kring Processfrågor, Marknad och Framtid2014Report (Other academic)
    Abstract [sv]

    Karlstads universitet har tagit på sig uppgiften att försöka sammanställa det kunnande som idag finns inom landet kring sulfitmassa och sulfitprocesser. Eftersom antalet massabruk som tillverkar sulfitmassa sakta sjunker är detta en viktig uppgift för att i någon mån kunna behålla det stora kunnande som en gång fanns kring denna process.

    Denna rapport belyser bl.a. viktiga processfrågor kring framställningen av pappers- och dissolvingmassor från sulfitprocessen.

  • 29.
    Arvsell, Karin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Termofil aerob rening av skogsindustriellt avloppsvatten: Ett försteg till en luftad damm2014Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The production of pulp and paper requires a large amount of energy and also large amounts of water which, by advantage, can be taken from a nearby lake or river. The wastewater passes through several different purification steps, such as mechanical, chemical and biological treatment before being reintroduced to the recipient. During aerobic biological treatment, a degradation and oxidation of the organic material occurs and is performed by microorganisms which require oxygen. Aeration consumes about half of the external plant's total energy and is aggravated by extractives present in the trees. At Stora Enso Skoghall mill an aerated pond is used as biological treatment, but there are troubles to get the oxygen to last for the entire pond. If a pre-treatment is placed before the pond this would be able to reduce the substances which demands oxygen. The implementation of the pre-treatment would be a MBBR (Moving Bed Biofilm Reactor) containing carriers and where thermophilic bacteria form biofilms.

    The experimental setups were built up in a laboratory at the University of Karlstad. The aerated ponds would resemble the aerated pond at Skoghall mill, with an identical retention time and contain equivalent microorganisms. The wastewater was continuously pumped into the experimental setups and was received from Skoghall mill and contained only CTMP water and CTMP mixed with water from the bleach plant and evaporation plant. As evaluation of the experiments analyzes of COD, TOC, SS, SVI, surface tension, extractives and microscopy were done.

    The results showed a relatively uniform COD and TOC reduction for the aerated ponds at around 70 %, which is comparable with the real pond at Skoghall mill. For the thermophilic MBBR with a temperature of 45° C and with probe 10-water, a capacity of reduction at 30 - 40% was noticed. The result with water containing only CTMP showed a reduction of 30%. Measurements of surface tension and extractives show if the concentration of extractives is decreasing in the thermophilic pre-treatments and also in the aerated ponds, which indicates a more effective oxygenation of the water. It was also found that the biofilm in the thermophilic stages are very sensitive and relatively easy to decimate if the conditions for the thermophilic bacteria are not optimal or if the incoming water contains any toxic substance.

    The sludge in all aerated ponds consisted of bacteria, protozoa and metazoa. The reference pond showed large and dense flocks while for the ponds that were preceded by thermophilic MBBR indicated less sludge and less dense flocks. For pond containing CTMP-water the flocks were small, but in addition, floating sludge was detected and foam problems arose.

  • 30. Backfolk, K.
    et al.
    Johansson, Caisa
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre.
    Peltonen, J.
    Association between a sodium salt of a linear dodecylbenzene sulphonate and a non-ionic fatty alcohol ethoxylate surfactant during film formation of styrene/butadiene latex2006In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2006, 291 (1-3), 38-44Article in journal (Refereed)
  • 31.
    Barbier, Christophe
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Beghello, L
    Magnetic printing for packaging industry: methods and feasibility2006Conference paper (Refereed)
  • 32.
    Barbier, Christophe
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Larsson, Per-Lennart
    Östlund, Sören
    Hallbäck, Nils
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Karathanasis, Michael
    On material characterization of paper coating materials by microindentation testing2005In: JCT: Journal of Coatings Technology, ISSN 0361-8773, Vol. 2, no 6, 463-471 p.Article in journal (Refereed)
    Abstract [en]

    Microindentation as a method for determining important material properties of paper coating materials is studied experimentally and numerically. The bulk of the investigation is concentrated upon the short-lived elastic part of a spherical indentation test, but determination of the failure stress of the coating is also discussed. The results indicate that microindentation can be a powerful tool for material characterization of these materials, but only if careful efforts are made to account for the influence from plasticity as well as from boundary effects

  • 33.
    Barbier, Christophe
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Larsson, PL
    KTH Stockholm.
    Östlund, S
    Experimental investigation of damage at folding of coated papers2002In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 17, no 1, 34- p.Article in journal (Refereed)
    Abstract [en]

    To achieve a better understanding of the folding properties of coated papers pertinent to the mechanical behaviour, a microscopic investigation was performed. The influence on the damage levels in the coating from such features as delamination, humidity and paper thickness have been studied

  • 34.
    Barbier, Christophe
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Larsson, PL
    Östlund, S
    Numerical investigation of folding of coated papers2005In: Composite StructuresArticle in journal (Refereed)
    Abstract [en]

    Folding of coated paper is examined numerically using the finite element method. Particular emphasis is put on the behaviour of field variables relevant for cracking of the coating layers. In the numerical analysis, the basepaper is modelled as an anisotropic elasticplastic material (both elastic and plastic anisotropy is accounted for) while the constitutive behaviour of the coating layers are approximated by classical (Mises) elastoplasticity. The numerical results suggest, among other things, that particular forms of plastic anisotropy can substantially reduce the maximum strain levels in the coating. It is also shown that delamination buckling, in the present circumstances, will have a very small influence on the strain levels in the coating layer subjected to high tensile loading

  • 35.
    Barbier, Christophe
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Larsson, PL
    Östlund, S
    On dynamic effects at folding of coated papers2005In: Composite StructuresArticle in journal (Refereed)
  • 36.
    Barbier, Christophe
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Larsson, PL
    KTH Stockholm.
    Östlund, S
    On the effect of high anisotropy at folding of coated papers2007In: Composite structures, ISSN 0263-8223, Vol. 72, no 3, 330-338 p.Article in journal (Refereed)
    Abstract [en]

    A finite element procedure, developed in order to account for the effect of high anisotropy at folding of coated papers, is presented. The anisotropic behaviour (with very low stiffness in the thickness direction) is modelled using stiff structural elements (trusses and beams). The numerical results indicate that high elastic anisotropy leads to lower strain levels at folding than reported in previous analyses where this effect was not accounted for. High plastic anisotropy, on the other hand, will contradict this result

  • 37.
    Barbier, Christophe
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Larsson, PL
    Östlund, S
    Eklund, J
    Folding of printed papers: experiments and numerical analysis2003Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Folding of digital prints has been investigated experimentally in order to determine the influence from different features on the residual strength of the folded paper. In particular, the effect of toner-layer, paper-fibre orientation and pre-creasing is investigated and the experimental results are supplemented with numerical ones based on the finite element method. The results indicate that creasing, and to a less extend also fibre orientation, is the most important factor influencing the residual tensile strength after folding

  • 38. Beder- Miller, Sandra
    et al.
    Andersson, Niclas
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Biazzo, Tom
    van Fleet, Rick
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Is Conductivity the Best Measurement of Bleach Plant Carryover?2014Conference paper (Refereed)
  • 39.
    Beghello, Luciano
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre.
    A New Generation of Durable Banknote Paper1999Conference paper (Other (popular science, discussion, etc.))
  • 40.
    Bengtsson, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Kartläggning av energiförluster: gällande klimatskal och ventilation för Stora Enso Timbers Pelletsfabrik i Grums2013Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
  • 41.
    Bengtsson, Peder
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Apply heat pump systems in commercial household products to reduce environmental impact: How to halve the electricity consumption for a household dishwasher2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the household appliance industry, heat pump systems have been used for a long time in refrigerators and freezers to cool food, and the industry has driven the development of small, high-quality, low-price heat pump components. In the last few decades, heat pump systems have been introduced in other household appliances, with the express purpose of reducing electricity consumption. Heat pump tumble dryers have been on the market since 2000 and dominate the market today. A heat pump dishwasher was introduced on the market in 2014 and a heat pump washing machine in 2016. The purpose of adding a heat pump system in these three products was to decrease electricity consumption.

    Papers I and II used a methodology where transient simulation models were developed and used to increase knowledge about how to decrease electricity consumption for a tumble dryer and a dishwasher by adding a heat pump system. Papers II to V showed that a lower electricity consumption and lower global warming potential together with an energy-efficient drying method, where no humid air evacuates to the kitchen, give a heat pump dishwasher competitive advantages compared to any conventional dishwasher currently on the market. Using simulations, this dissertation concludes that a future commercial heat pump dishwasher, using R600a as a refrigerant, will reduce electricity consumption and total equivalent warming impact (TEWI) by 50% compared to the conventional dishwasher.

    The willingness from the customer chain to pay extra for this heat pump dishwasher is because of the decreases electricity consumption and the fact that no humid air evacuates to the kitchen. This willingness makes the heat pump dishwasher to a variant which have possibility to succeed on the future market.

    The challenge for the manufacturer is to develop and produce a high-quality heat pump dishwasher with low electricity consumption, predict future willingness to pay for it, and launch it on the market at the right moment with the right promotion in order to succeed.

  • 42.
    Bengtsson, Peder
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Increasing the value of household appliances by adding a heat pump system2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Historically, domestic tasks such as preparing food and washing and drying clothes and dishes were done by hand. In a modern home many of these chores are taken care of by machines such as washing machines, dishwashers and tumble dryers. When the first such machines came on the market customers were happy that they worked at all! Today, the costs of electricity and customers’ environmental awareness are high, so features such as low electricity, water and detergent use strongly influence which household machine the customer will buy. One way to achieve lower electricity usage for the tumble dryer and the dishwasher is to add a heat pump system.

    The function of a heat pump system is to extract heat from a lower temperature source (heat source) and reject it to a higher temperature sink (heat sink) at a higher temperature level. Heat pump systems have been used for a long time in refrigerators and freezers, and that industry has driven the development of small, high quality, low price heat pump components. The low price of good quality heat pump components, along with an increased willingness to pay extra for lower electricity usage and environmental impact, make it possible to introduce heat pump systems in other household products.

    However, there is a high risk of failure with new features. A number of household manufacturers no longer exist because they introduced poorly implemented new features, which resulted in low quality and product performance. A manufacturer must predict whether the future value of a feature is high enough for the customer chain to pay for it. The challenge for the manufacturer is to develop and produce a high-performance heat pump feature in a household product with high quality, predict future willingness to pay for it, and launch it at the right moment in order to succeed.

    Tumble dryers with heat pump systems have been on the market since 2000. Paper I reports on the development of a transient simulation model of a commercial heat pump tumble dryer. The measured and simulated results were compared with good similarity. The influence of the size of the compressor and the condenser was investigated using the validated simulation model. The results from the simulation model show that increasing the cylinder volume of the compressor by 50% decreases the drying time by 14% without using more electricity. 

    Paper II is a concept study of adding a heat pump system to a dishwasher in order to decrease the total electricity usage. The dishwasher, dishware and water are heated by the condenser, and the evaporator absorbs the heat from a water tank. The majority of the heat transfer to the evaporator occurs when ice is generated in the water tank. An experimental setup and a transient simulation model of a heat pump dishwasher were developed. The simulation results show a 24% reduction in electricity use compared to a conventional dishwasher heated with an electric element. The simulation model was based on an experimental setup that was not optimised. During the study it became apparent that it is possible to decrease electricity usage even more with the next experimental setup.

  • 43.
    Bengtsson, Peder
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences. ASKO Appliances AB, Lidköping, Sweden.
    Berghel, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Concept Study of a New Method for Drying Dishware in a Heat Pump Dishwater2017In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, 1-10 p.Article in journal (Refereed)
    Abstract [en]

    In a heat pump dishwasher, the whole dishwasher with the cabinet, dishware and process water is the heat sink, while a water tank, whose contents will freeze, is the heat source. The aim of the experimental concept study presented here was to evaluate a new drying method for a heat pump dishwasher. In this method, the drying of the dishware occurs as a fan circulates humid air in a closed system in which the water on the dishware evaporates inside the warm dishwasher cabinet and then condenses on a cold surface of the frozen water tank. The evaluation of drying performance was based on the European standard EN50242, which considers visible water drops left on the dishware after a completed dishwashing cycle. The results showed that this new closed drying method was more energy efficient compared to an existing open drying method, and that the drying start temperature and the drying time had a significant effect on the drying performance. Its lower electricity consumption and the fact that it does not vent humid air into the kitchen gives this heat pump dishwasher a competitive advantage over dishwashers using an open drying method.

  • 44.
    Bengtsson, Peder
    et al.
    ASKO Appliances AB, Sockerbruksgatan 3, SE-53140 Lidkoping, Sweden..
    Berghel, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Study of using a capillary tube in a heat pump dishwasher with transient heating2016In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 67, 1-9 p.Article in journal (Refereed)
    Abstract [en]

    For competitive purposes, manufacturers of household appliances need to produce appliances that use less electricity. One way of doing this for a dishwasher is to add a heat pump system. Previous studies using R134a as refrigerant have shown that the addition of a heat pump can reduce total electricity consumption by about 24%. This paper reports on the use of a capillary tube in a heat pump dishwasher during the transient heating period. Working with an available compressor, the mass of R600a and the length of a 0.9 mm capillary tube were varied in order to find the configuration with the lowest electricity consumption. Three methods of calculating the length of the capillary tube were used to determine five lengths for evaluation. The results show that using a single capillary tube throughout the transient heating period yields similar electricity consumption to a variable expansion device which occurred by switching the capillary tube between two or three different lengths during the heating period.

  • 45.
    Bengtsson, Peder
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Berghel, Jonas
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Renström, Roger
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    A household dishwasher heated by a heat pump system using an energy storage unit with water as the heat source2015In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 49, 19-27 p.Article in journal (Refereed)
    Abstract [en]

    Electricity usage by a household dishwasher can be reduced by using a heat pump system to heat the dishwasher cabinet, dishware and washing water. The evaporator obtains the energy from an energy storage unit which consists of a container filled with water which freezes to ice. The majority of the heat transfer from the energy storage to the evaporator occurs when ice is created in the energy storage unit. A transient simulation model of a dishwasher with a heat pump system was developed and compared to an experimental setup with good agreement. A simulation study of the compressor cylinder volume and the compressor operating time was performed. The results showed a 24% reduction in total electricity use compared to a dishwasher cycle using a traditional electric element.

  • 46.
    Bengtsson, Peder
    et al.
    ASKO Appliances AB, Lidköping, Sweden.
    Berghel, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Renström, Roger
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Performance Study of a Closed-Type Heat Pump Tumble Dryer Using A Simulation Model and an Experimental Set-Up2014In: Drying Technology, ISSN 0737-3937, E-ISSN 1532-2300, Vol. 32, no 8, 891-901 p.Article in journal (Refereed)
    Abstract [en]

    In the interests of competitiveness, manufactures of tumble dryers are seeking to reduce both their electricity use and the drying time. This study examines how the cylinder volume of the compressor and the total heat transfer of the condenser influence the drying time and electricity use in a heat pump tumble dryer. A transient simulation model was developed and compared to an experimental set-up with good similarity. The simulations show that increasing the cylinder volume of the compressor by 50% decreases the drying time by 14% without using more electricity.

  • 47.
    Berghel, Jonas
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Frodeson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Granström, Karin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Renström, Roger
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Ståhl, Magnus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Varför får inte villaägaren driva kvalitetsutvecklingen på bränslepellets?2011In: Bioenergi: utmaningar och möjligheter / [ed] K. Delin, L. Persson, P.-A. Wikström, Gävle: Region Gävleborg , 2011, 31-33 p.Chapter in book (Other academic)
  • 48.
    Berghel, Jonas
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Renström, Roger
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    An Experimental Study on the Influence of Using a Draft Tube in a Continuous Spouted Bed Dryer2014In: Drying Technology, ISSN 0737-3937, E-ISSN 1532-2300, Vol. 32, no 5, 519-527 p.Article in journal (Refereed)
    Abstract [en]

    Further increasing the production of processed biofuel also increases the demands on drying capacity. With the aim of increasing the heat capacity flow, experimental tests have been performed on the process of drying sawdust in a continuous spouted bed dryer with nine different draft tube designs. The results showed that a draft tube with an increased length and an increased disengagement height decreased the dry substances' flow rate throughout the dryer. The results also showed that the mass of the material in the dryer was approximately the same in all the tests. This means that the draft tubes, no matter their size, do not influence the amount of material in the dryer.

  • 49.
    Berghel, Jonas
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Renström, Roger
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Shi yong dao liu guan dui lian xu pen dong gan zao qi de ying xiang (Effects of using draft tubes in a continued spouted bed)2013In: Drying Technology & Equipment, ISSN 1727-3080, Vol. 1727-3080, no 3, 9-18 p.Article in journal (Refereed)
  • 50.
    Berghel, Jonas
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Ståhl, Magnus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    How residence time in the mixing conditioner affects the quality in wood fuel pellets2016Conference paper (Other academic)
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