Change search
Link to record
Permanent link

Direct link
Alternative names
Publications (10 of 16) Show all publications
Sandberg, M., Frodeson, S., Stawreberg, L. & Tumuluru, J. S. (2024). Forest Industrial Waste Materials Upgraded to Fertilizer Pellets for Forest Soil. Sustainability, 16(7), 2868-2868
Open this publication in new window or tab >>Forest Industrial Waste Materials Upgraded to Fertilizer Pellets for Forest Soil
2024 (English)In: Sustainability, E-ISSN 2071-1050, Vol. 16, no 7, p. 2868-2868Article in journal (Refereed) Published
Abstract [en]

In a circular economy, the efficient utilization of all materials as valuable resources, with a focus on minimizing waste, is paramount. This study shows the possibilities of upgrading the lowest-valued residuals from the forest industry into a new product with both liming and fertilizing properties on forest soil. Hydrothermal carbonized sludge mixed with bark and ash in the proportions of 45:10:45 was densified into fertilizer pellets that meet the nutrient requirements of 120 kg N per hectare when 7 tons of pellets is spread in forests. The pellets met a high-quality result according to durability and density, which were above 95% and 900 kg/m3. However, pellets exposed to wet and cold conditions lost their hardness, making the pellets dissolve over time. Small amounts, <5‰, of nutrients, alkali ions, and heavy metals leached out from the pellets under all conditions, indicating good properties for forest soil amendment. The conclusion is that it is possible to close the circle of nutrients by using innovative thinking around forest industrial residual products.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
circularity, densification, hydrothermal carbonization, forest-industrial-waste-derived hydrochar
National Category
Forest Science
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-99144 (URN)10.3390/su16072868 (DOI)001201643500001 ()2-s2.0-85190370423 (Scopus ID)
Funder
Vinnova, 2019-04457
Available from: 2024-04-02 Created: 2024-04-02 Last updated: 2026-02-12Bibliographically approved
Almusaed, A., Almssad, A., Andersson, N. & Brunzell, L. (2022). CDIO Initiative on Student Engagement by Effective Syncretic (lectures – seminars). In: O. Noroozi; I. Sahin (Ed.), Proceedings of IHSES 2022, International Conference on Humanities, Social and Education Sciences, Los Angeles, USA: . Paper presented at International Conference on Humanities, Social and Education Sciences (pp. 249-261). USA: ISTES Organization, 1
Open this publication in new window or tab >>CDIO Initiative on Student Engagement by Effective Syncretic (lectures – seminars)
2022 (English)In: Proceedings of IHSES 2022, International Conference on Humanities, Social and Education Sciences, Los Angeles, USA / [ed] O. Noroozi; I. Sahin, USA: ISTES Organization , 2022, Vol. 1, p. 249-261Conference paper, Published paper (Refereed)
Abstract [en]

New trends such as globalization, the knowledge economy, and the information technology revolution have become essential factors affecting the development of universities in the new era. These trends have profoundly impacted the survival and growth of universities. First, universities need to shoulder the knowledge creation work in many fields related to human survival and development in the era of the knowledge economy. Secondly, they must adapt to the influence of the technological revolution on human knowledge acquisition methods and change traditions. I will further explore the new requirements for talents in the new era and adjust our talent training concepts, values and models. How universities respond to challenges through operational changes and explore new models of higher education in line with social development in the new era is a topic that universities worldwide need to consider. The study aims to create an effective model to improve the interaction between the lectures and seminars objectives and activities based on CDIO standards 3 and 8. The integrated curriculum and active learning are crucial for improving future students' engineers' skills.

Consequently, students will participate efficiently in the learning process. The study will focus on the concept of a "student-centered" learning environment based on the active learning model by using the research to create effective student engagement in the learning process. The work's positioning, goals, and learning model promotes the improvement of the student's engagement and learning mode in this context, pay attention to the course-student interaction in the process, stimulates students' learning initiative, and promote the teaching reform of participating colleges. The study aims to Increase the students' work and outcome towards creative results.

Place, publisher, year, edition, pages
USA: ISTES Organization, 2022
National Category
Educational Sciences
Research subject
Educational Work; Construction Engineering
Identifiers
urn:nbn:se:kau:diva-91772 (URN)978-1-952092-33-6 (ISBN)
Conference
International Conference on Humanities, Social and Education Sciences
Available from: 2022-09-04 Created: 2022-09-04 Last updated: 2026-02-12Bibliographically approved
Brunzell, L. & Renström, R. (2019). Recommendations for revising the energy label system for dishwashers: Supporting sustainable development and usage through the interaction of energy labels, technical improvements and consumer behaviour. Energy Efficiency, 13(1), 145-155
Open this publication in new window or tab >>Recommendations for revising the energy label system for dishwashers: Supporting sustainable development and usage through the interaction of energy labels, technical improvements and consumer behaviour
2019 (English)In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, Vol. 13, no 1, p. 145-155Article in journal (Refereed) Published
Abstract [en]

Historically, domestic chores such as washing dishes were all done by hand. Today it is estimated that 44% of the households in the EU are equipped with a dishwasher. In this article, we discuss the connections between technical developments, consumer behaviour and the test standard for energy labels. The aim of this study is to provide recommendations for future work that would strengthen the role of the energy label in order to promote the more sustainable technical development of household appliances. Technical developments are compared with the consequences of different consumer behaviour. It was found that technical developments could reduce annual energy use, but depending on the implemented technology, this is often complex and requires additional components. On the other hand, a consumer can easily increase energy usage by 50% without being aware of doing so, when goods are pre-treated, appliances incorrectly loaded, or inappropriate programs selected. Our recommendation is first of all to encourage the use of dishwashers as they consume less energy and water compared with washing up manually. A holistic approach should be taken to updating the energy labelling system. Actual consumer behaviour must be taken into account and, perhaps most importantly, as dishwashers are becoming ever more energy efficient, consumers must be educated in using the machines in an environmentally friendly way. We conclude that the energy labelling system is outdated; it must be fundamentally revised and must take into account consumer behaviour.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Energy label, Household appliances, Pre-treatment, Water consumption
National Category
Energy Engineering
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-76609 (URN)10.1007/s12053-019-09835-6 (DOI)000520140800010 ()2-s2.0-85076593009 (Scopus ID)
Available from: 2020-01-30 Created: 2020-01-30 Last updated: 2026-02-12Bibliographically approved
Renström, R. & Brunzell, L. (2018). En introduktion för att studenter ska utveckla egna strategier för skrivandet. In: Madelaine Johansson, Lena E. Johansson (Ed.), Studentaktiva lärande- och examinationsformer: Bidrag från universitetspedagogisk konferens 2017 (pp. 93-108). Karlstad: Karlstads universitet
Open this publication in new window or tab >>En introduktion för att studenter ska utveckla egna strategier för skrivandet
2018 (Swedish)In: Studentaktiva lärande- och examinationsformer: Bidrag från universitetspedagogisk konferens 2017 / [ed] Madelaine Johansson, Lena E. Johansson, Karlstad: Karlstads universitet, 2018, p. 93-108Chapter in book (Other academic)
Abstract [sv]

I högre utbildning är akademiskt skrivande något som studenter behöver stöd att utveckla genom hela sin utbildning. Handledningen är en central del i denna process men det finns en risk att handledaren i stället för att lyfta halvfärdiga texter i själva verket drar ner studenter eller lämnar otydliga synpunkter. Det finns även en risk att handledaren över skrivarbetet och gör det till sitt.

Vi arbetar med en handledningsmodell som vi kallar ”Direkthandledning”. Modellen ger stor frihet för förändringar och stora delar avutbildningsmiljön arbetar med liknande modeller. Drivkraften är att göra handledningen effektivare, att öka studenternas respons för lärarnas synpunkter samt ge studenterna egna strategier för sitt skrivande. Direkthandledningsmodellen används i hela utbildningen och i denna artikel presenteras introduktionen. I handledningsmodellen separeras innehåll och form. I introduktionen handleds enbart formen, hur rapporten är formaliserad, strukturerad och skriven.I direkthandledningsmodellen får studenten alltid en tydlig process och kravspecifikation på vad som förväntas. I introduktionen genomförs en individuell studie och först när studenten skrivit en inledning, metod och resultat som är i läs- och kommentarbart skick, får studenten handledning. Texten skall då följa en utskickad och kommunicerad mall och struktur. Återkopplingen utgår från kravspecifikationen. När studenten kommer till handledningen har handledare och student en diskussion kring hur arbetet är presenterat, inget annat. Under handledningen får studenten tydlig information om hur denne ligger till i förhållande till kravspecifikationen.

Modellen har lett till betydande förbättringar av responsen på synpunkter. Studenter uppger att de börjat utveckla egna strategier för sitt skrivande.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2018
Series
Utveckling av undervisning och examination i högre utbildning: utgiven av Universitetspedagogiska enheten vid Karlstads universitet ; 2018:1
National Category
Educational Sciences
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-72045 (URN)978-91-7063-869-5 (ISBN)978-91-7063-964-7 (ISBN)
Available from: 2019-05-15 Created: 2019-05-15 Last updated: 2026-02-12Bibliographically approved
Renström, R., Johansson-Cider, H. & Brunzell, L. (2018). Energy performance of an industrial superheated steam heat pump flash dryer for drying of bio-fuel. In: Carcel, JA Clemente, G GarciaPerez, JV Mulet, A Rossello, C (Ed.), IDS'2018: 21ST INTERNATIONAL DRYING SYMPOSIUM. Paper presented at 21st International Drying Symposium (IDS); Valencia, SPAIN; Date: SEP 11-14, 2018 (pp. 1495-1502). University Politecnica Valencia
Open this publication in new window or tab >>Energy performance of an industrial superheated steam heat pump flash dryer for drying of bio-fuel
2018 (English)In: IDS'2018: 21ST INTERNATIONAL DRYING SYMPOSIUM / [ed] Carcel, JA Clemente, G GarciaPerez, JV Mulet, A Rossello, C, University Politecnica Valencia , 2018, p. 1495-1502Conference paper, Published paper (Refereed)
Abstract [en]

Drying is an energy demanding industrial process and methods for reducing the energy consumption of drying is of interest to industry as well as society. This article presents the drying system of a biofuel factory. Steam is used as the refrigerant. Superheated steam is used as drying gas in a flash dryer with 28.8 tons/h dewatering capacity. The system includes an energy recovering water heat pump that receives its heat from the excess drying steam and heats the dryer. The SMER of the drying process ranges between 3 and 4 and the COP of the heat pump process ranges between 4 and 5.5 during one production season of peat drying. Variations in performance can be explained by variations in inlet moisture content and production rate. The example of this drying system shows the feasibility of drying in superheated steam, heat pump drying and water as refrigerant in high-temperature heat pumps.

Place, publisher, year, edition, pages
University Politecnica Valencia, 2018
Keywords
steam drying, heat pump process, peat, sawdust, industrial operation
National Category
Energy Systems
Research subject
Energy Technology
Identifiers
urn:nbn:se:kau:diva-74340 (URN)10.4995/ids2018.2018.7379 (DOI)000477977800187 ()978-84-9048-688-7 (ISBN)
Conference
21st International Drying Symposium (IDS); Valencia, SPAIN; Date: SEP 11-14, 2018
Available from: 2019-08-15 Created: 2019-08-15 Last updated: 2026-02-12Bibliographically approved
Karlsson, J., Stawreberg, L. & Govindarajan, V. (2018). Material-flow analysis, energy analysis, and partial environmental-LCA of a district-heating combined heat and power plant in Sweden. Energy Journal, 144, 31-40
Open this publication in new window or tab >>Material-flow analysis, energy analysis, and partial environmental-LCA of a district-heating combined heat and power plant in Sweden
2018 (English)In: Energy Journal, ISSN 0195-6574, E-ISSN 1944-9089, Vol. 144, p. 31-40Article in journal (Refereed) Published
Abstract [en]

Combined heat and power (CHP) plants are a great improvement over waste-to-energy incineration plants supplying only heat, and power plants supplying only electricity. The primary purpose of a functioning CHP plant however, may be to provide district heating services, and thereby its main output will be heat energy. This paper is a case study commissioned by Karlskoga Energi och Miljö AB (KEMAB in short; Karlskoga Energy and Environment) in the Värmland State of south-central Sweden, and focuses on the functioning of the CHP plant owned and operated by the company. The life-cycles of the fuels used by the CHP – household/industrial waste, bio-oil, light fuel oil, wood waste, wood chips, a slaughterhouse-waste-derived product and peat to generate 202,222 MWh of heat, 119,234 MWh of steam and 28,220 MWh of electricity have been studied, and the carbon footprint calculated for year-2016. Using two sets of emissions factors for the combustion stage of the life-cycle, as part of a data uncertainty analysis, the total emissions were 44,000 tonnes carbon dioxide equivalents (CO2-eq) and 58,000 tonnes CO2-eq respectively. A quasi-realistic scenario analysis in which plastics are not available for incineration and have to be substituted with alternatives has also been carried out, and while wood waste has been suggested as the best alternative with regard to greenhouse gas (GHG) emissions, availability permitting, a combination of alternatives has been mooted as the practical option.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Combined Heat and Power, District Heating, MFA, LCA
National Category
Environmental Engineering Mechanical Engineering
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-65302 (URN)10.1016/j.energy.2017.11.159 (DOI)000425561500004 ()
Available from: 2017-11-30 Created: 2017-11-30 Last updated: 2026-02-12Bibliographically approved
Brunzell, L. & Renström, R. (2018). Utformning av aktiva pedagogiska möten i en kurs med flippat lärande. In: Madelaine Johansson, Lena E. Johansson (Ed.), Studentaktiva lärande- och examinationsformer: Bidrag från universitetspedagogisk konferens 2017 (pp. 21-34). Karlstad: Karlstads universitet
Open this publication in new window or tab >>Utformning av aktiva pedagogiska möten i en kurs med flippat lärande
2018 (Swedish)In: Studentaktiva lärande- och examinationsformer: Bidrag från universitetspedagogisk konferens 2017 / [ed] Madelaine Johansson, Lena E. Johansson, Karlstad: Karlstads universitet, 2018, p. 21-34Chapter in book (Other academic)
Abstract [sv]

Att använda flippat lärande i undervisningen har blivit mer och mer vanligt i högre utbildning. Studier pekar på att den formen av undervisning leder till ökad förståelse, ett ökat engagemang och motivation hos studenterna. Dock finns ett uttalat behov av ytterligare forskning inom området. I denna studie ligger fokus på hur de pedagogiska mötena i en typisk teknisk grundkurs kan utformas för att vara aktiva och främja lärandet i de högre kunskapsnivåerna. Den nya utformningen bygger på att traditionella möten med studenter såsom föreläsningar och lektioner har bytts ut mot diskussionstillfällen och laborationer. Räkneövningar finns i båda upplägg men fokus i det nya ligger i att arbeta med koncept och hur problem ställs upp. Den operativa räkningen lämnas alltid till studenterna. Resultaten blir att lärarna idag kan möta studenterna och agera som en coach i deras lärande, studenterna är mer aktiva och vi arbetar med kunskapsmål där vi analyserar, kritiskt utvärderar, utformar system och gör avvägda antaganden. Genomströmningen har ökat från mellan 40-50% till mellan 60-70% trots ett ökat krav på förståelsen i examinationen.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2018
Series
Utveckling av undervisning och examination i högre utbildning: utgiven av Universitetspedagogiska enheten vid Karlstads universitet ; 2018:1
National Category
Educational Sciences
Research subject
Subject-specific education
Identifiers
urn:nbn:se:kau:diva-72044 (URN)978-91-7063-869-5 (ISBN)978-91-7063-964-7 (ISBN)
Available from: 2019-05-15 Created: 2019-05-15 Last updated: 2026-02-12Bibliographically approved
Stawreberg, L. & Nilsson, L. (2013). Potential Energy Savings Made by Using a Specific Control Strategy when Tumble Drying Small Loads. Applied Energy, 102, 484-491
Open this publication in new window or tab >>Potential Energy Savings Made by Using a Specific Control Strategy when Tumble Drying Small Loads
2013 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 102, p. 484-491Article in journal (Refereed) Published
Abstract [en]

Tumble dryers manufactured today are optimised for their maximum capacity, i.e., 6–8 kg of dry load. An average washing load in ordinary households lands at between 2 and 3.5 kg dry load, which implies that the drying load is even smaller. The energy efficiency decreases with reduced drying load. The aim of this study is to establish a mathematical model for studying alternative control strategies for the venting tumble dryer in order to increase the energy efficiency of drying small loads. Two series of test runs were performed: the first series with three different drying loads was used as reference tests for validation of the mathematical model, and the second series was performed with airflow reduction. The model shows good agreement with the test runs. Two control strategies were tested using the model on the smallest drying load. By lowering the heat supply to the heater and by reducing the airflow, the energy efficiency increases by 6% in a small load drying cycle. It was not possible, however, for the investigated dryer, to reach the same energy efficiency for small loads as for the maximum drying load by using a control strategy.

National Category
Energy Systems
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-8245 (URN)10.1016/j.apenergy.2012.07.045 (DOI)000314190800054 ()
Available from: 2011-09-14 Created: 2011-09-14 Last updated: 2026-02-11Bibliographically approved
Renström, R., Berghel, J., Frodeson, S., Granström, K., Nilsson, L., Lestelius, M., . . . Stawreberg, L. (2013). The drying process from a product perspective. In: : . Paper presented at Nordic Drying Conference - NDC, Copenhagen, Danmark 5-7 juni 2013.
Open this publication in new window or tab >>The drying process from a product perspective
Show others...
2013 (English)Conference paper, Published paper (Refereed)
National Category
Energy Engineering
Research subject
Energy Technology
Identifiers
urn:nbn:se:kau:diva-29707 (URN)
Conference
Nordic Drying Conference - NDC, Copenhagen, Danmark 5-7 juni 2013
Available from: 2013-10-21 Created: 2013-10-18 Last updated: 2026-02-11Bibliographically approved
Stawreberg, L., Berghel, J. & Renström, R. (2012). Energy Losses by Air Leakage in Condensing Tumble Dryers. Applied Thermal Engineering, 37(May), 373-379
Open this publication in new window or tab >>Energy Losses by Air Leakage in Condensing Tumble Dryers
2012 (English)In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 37, no May, p. 373-379Article in journal (Refereed) Published
Abstract [en]

Tumble dryers, used for the drying of textiles, consume a considerable amount of electricity due to the large number of dryers in use. A large amount of this electricity is produced from coal, making it important to reduce the electricity use and, hence, the carbon dioxide emissions. Earlier studies made on the condensing tumble dryer have pointed out that leakage is one of the parameters affecting the electricity use for the drying process. With a view to reducing the energy use, leakage was estimated through measurements and modelling. Energy balances were used in order to verify the leakage. The energy balance showed good agreement with the results from the model and confirms that the leakage out from the dryer arises mainly between the heater and the drum where the air is hot and has low relative humidity. Large leakage at this location is detrimental for the energy efficiency of the dryer, meaning that the leakage must be reduced in order to obtain a reduced energy use. Results from the model also point out that even small changes in the size of gaps, or changes to the pressure in the internal system, result in a significant change in leakage from the dryer

Place, publisher, year, edition, pages
Elsevier, 2012
Keywords
Energy balance, Tumble dryer, Leakage, Textile, Domestic
National Category
Energy Systems
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-8246 (URN)10.1016/j.applthermaleng.2011.11.051 (DOI)000301026600045 ()
Available from: 2011-09-14 Created: 2011-09-14 Last updated: 2026-02-11Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1282-968x

Search in DiVA

Show all publications