| 1. |
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| 2. |
- Danielski, Itai, 1973-, et al.
(författare)
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Air source heat pumps and their role in the Swedish energy system
- 2012
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Ingår i: Support your future today; Turning environmental problems into business opportunities.
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Konferensbidrag (refereegranskat)abstract
- Newly produced air source heat pumps can provide heat energy from outdoor air at temperature as low as -20°C. As a result they could be utilized during most days of the year even in the cold Nordic climates. The drawback of air source heat pumps is the reduction in efficiency as the outdoor air become colder, resulting in lower heat supply in times when it is most needed. Despite its inverse relationship between efficiency and outdoor temperature, air source heat pumps were installed in 57000 detached houses in Sweden during 2010 alone, which is 3% of the total detached houses stock. That makes air source heat pumps the most sold heating technology for detached houses in Sweden during 2010, 1.6 times more than the number of installations of ground source heat pump and 3 times more than the number of connections of detached houses to district heating during the same year. Similar trends can be found in other Nordic countries.This study compares the use of an air source heat pump with other existing commercial technologies in detached houses and analyzes the impacts on primary energy use, on final energy use, on electricity production and on costs benefits for house owners. It was found that converting existing electric heated Swedish detaches houses to district heating with biomass based CHP or bed-rock heat pump could reduce the use of resources, which could benefit Sweden as a society. Converting electric heated Swedish detaches houses to district heating or pellets stove could reduce power demand and level out the power demand load curve. That would benefit utilities of power supply as it could secure power supply. However cost effectiveness in one of most important drivers for house owners of detached houses to choose energy efficiency measures. For that reason house owners may most likely benefit by the installation of air-source heat pumps.
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| 3. |
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| 4. |
- Danielski, Itai, 1973-, et al.
(författare)
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Atrium in residential buildings – a design to enhance social interaction in urban areas in Nordic climates
- 2018
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Ingår i: Cold Climate HVAC 2018. - Cham : Springer. - 9783030006617 - 9783030006624 ; , s. 773-789
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Bokkapitel (refereegranskat)abstract
- The design concept of conditioned atria receive growing popularity in both commercial and service buildings all over the world, but still not common in the residential sector. This study used a psychological framework to examine if building design with enclosed heated atria in apartment buildings can enhance sense of community and social interactions in Nordic climates. A qualitative study was conducted to understand the perception of residents living in apartment buildings with heated atrium. One of the few examples in Sweden. This was compared to the experience of residents in a “traditional” apartment building without an atrium. The questionnaire was comprised of six parts: (i) socio-demographic aspects; (ii) information about the apartment; (iii) social activities within the building; (iv) social interaction with neighbours; (v) information about principles in life; and (vi) sense of community linked to their homes.The results showed significant social differences between the residents of the atrium and “traditional” buildings, which could not be explained solely by differences in preferences and principles in life. A large proportion of the social differences between the buildings could be explained by the building design, as the common and semi-private areas within the atrium building provide opportunities to establish social interactions. The residents in the atrium building was found to have greater sense of community and higher frequency of interactions, which are both parts of social sustainability.
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| 5. |
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| 6. |
- Danielski, Itai, 1973-, et al.
(författare)
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Design för energieffektiv vardag : Slutrapport projekt DEVA-skolor
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Dålig inomhusmiljö i grundskolor i Sverige verkar vara ett problem i många kommuner. I det här projektet har man tittat på om en installation av en stor mängd växter i ett klassrum skulle kunna ändra på det. Det finns nämligen forskning om visar att vi mår, både fysiskt och psykiskt, bättre om vi är omgivna av växter. Fysiskt för att de kan rena luften och omvandla koldioxiden till syre. Dessutom ökar de luftfuktigheten och reglerar temperaturen. Psykiskt kanske för att vi är en del av naturen och har levt i den största delen av mänsklighetens historia. Växter kan också skapa bättre akustik i rummet genom att absorbera ljudvågor. Dessutom finns det tidigare studier som visar att växterna kan öka både koncentrationsförmågan och minnet.Projektet hade tre olika perspektiv; design, miljö och hälsa. Platsen för projektet var en grundskola belägen i ett mindre landsbygdssamhälle i norra delarna av Sverige. Totalt installerades 350 gröna växter i fyra växtställningar, dessa fördelades sedan på två olika klassrum med ca 25 elever ur årskurs 8 vardera. Ett liknande klassrum (åk9) bredvid dessa användes som referensobjekt. Växtställningarna designades av industridesignstudenter på Mittuniversitetet och skulle resultera i fungerande prototyper med automatisk bevattning. Projektet pågick under två terminer, höstterminen 2019 och vårterminen 2020.Mätningar av inomhustemperaturen visade att de gröna växterna bidrar till en mer stabil temperatur och till och med kan öka temperaturen något, vilket kan användas för att minska värmebehovet. Effekterna på luftfuktighet var endast högre i klassrummen med växter under natten när ventilationsflödet var lågt. Koldioxidnivåerna i klassrummen med växterna var 10 % lägre under undervisningstiden jämfört med kontrollklassrummet vilket indikerar att gröna växter skulle kunna användas för att minska ventilationsluftflödet och därigenom minska värmeenergiförluster. Energiberäkningen visade upp till 18% minskning på uppvärmningsbehovet. Mängden luftburna partiklar var redan låg och man kunde inte se någon förändring efter installationen av växterna.I början uppskattade både lärare och elever att de hade fått ett “grönt klassrum”. Minnet och koncentrationsförmågan hos eleverna blev bättre. I mätningen ett halvår senare hade dock effekten avtagit. Det är svårt att säga om detta berodde på hemmablindhet, Covid 19-pandemin (som hade brutit ut en månad tidigare) eller för att det var problem med några av bevattningssystemen som gjorde att vissa växter vissnade. Kanske en kombination.Resultaten av det här projektet kan ge kunskap och inspiration till kommuner och skolor om hur de kan förbättra inomhusklimatet med växter som ett kostnadseffektivt komplement till befintliga ventilationssystem som också kan förbättra elevernas och lärarnas prestationer och välbefinnande. Det är värt att notera att den här studien genomfördes på landsbygden där det redan är en bra luftkvalitet. Därför vore intressant att genomföra en liknande studie i ett storstadsområde men sämre luftkvalitet och även i andra med typer av byggnader med lägre ventilationsflöde.Det är också värt att notera att när projektet befanns sig i halvtid inträffade en pandemi, covid-19, som gav en betydande påverkan på både många samhällsfunktioner och för många människor. Detta kan ha påverkat resultatet av effekterna i mätningarna av hälsa och koncentration.
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| 7. |
- Danielski, Itai, 1973-, et al.
(författare)
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Diagnosis of buildings' thermal performance - a quantitative method using thermography under non-steady state heat flow
- 2015
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 83, s. 320-329
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Tidskriftsartikel (refereegranskat)abstract
- This study describes a quantitative method using thermography to measure the thermal performance of complete building envelope elements that are subjected to non-steady state heat flow. The method presumes that thermal properties of external walls, like conductivity, could still be obtained by a linear regression over values of independent measurements. And therefore could be used during fluctuating indoor and outdoor thermal conditions. The method is divided into two parts. First, the convection heat transfer coefficient is measured by heat flux meters (HFM) and thermography. And then, the overall heat transfer coefficient of a complete building element is measured by thermography to include all non-uniformities.In this study the thermal performance of a 140 mm thick laminated timber wall was measured. The wall was subjected to the outdoor weather conditions in Östersund, Sweden during January and February. The measurement values were found to have a large disparity as expected due to the rapid change in weather conditions. But still a linear regression with low confidence interval was obtained. The thermography results from a small uniform wall segment were validated with HFM measurements and 4% difference was found, which suggest that the two methods could be equally effective. Yet, thermography has the advantage of measuring surface temperature over large area of building element. The overall heat transfer coefficient of a large wall area was found to be 11% higher in comparison to the HFM measurements. This indicates that thermography could provide a more representative result as it captures areas of imperfections, point and linear thermal bridges.
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| 8. |
- Danielski, Itai, 1973-
(författare)
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Energy efficiency of new residential buildings in sweden : Design and Modelling Aspects
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Energy security and climate change mitigation have been discussed in Sweden since the oil crisis in the 1970s. Sweden has since then increased its share of renewable energy resources to reach the highest level among the EU member states, but is still among the countries with the highest primary energy use per capita. Not least because of that, increasing energy efficiency is important and it is part of the Swedish long term environmental objectives. Large potential for improving energy efficiency can be found in the building sector, mainly in the existing building stock but also in newly constructed buildingsIn this thesis, criteria for energy efficiency in new residential buildings are studied, several design aspects of residential buildings are examined, and possible further analysis from an energy system perspective discussed. Three case studies of existing residential buildings were analysed, including one detached house and multi-storey apartment buildings. The analysis was based on both energy simulations and measurements in residential buildings.The results show that the calculated specific final energy demand of residential buildings, before they are built, is too rough an indicator to explicitly steer society toward lower final energy use in the building sector. One of the reasons is assumptions made during calculation before the buildings is built. Another reason is the interior building design. A design that includes relatively large areas of heated corridors, service and storage rooms will lower the specific final energy demand without improving the building energy efficiency, which might increase both the total final energy demand and the use of construction materials in the building sector.Efficient thermal envelopes are essential in construction of energy efficient buildings, which include the thermal resistance and also the shape of the building. The shape factor of buildings was found to be an important variable for heat demand in buildings located in temperate and colder climates, particularly if they are exposed to strong winds.From a system perspective, energy efficiency measures and the performance of the end use heating technology in buildings should be evaluated together with the energy supply system, including the dynamic interaction between them.
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| 9. |
- Danielski, Itai, 1973-
(författare)
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Energy performance of residential buildings : projecting, monitoring and evaluating
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Energy security and climate change mitigation have been discussed in Sweden since the oil crisis in the 1970s. Sweden has since then increased its share of renewable energy resources to reach the highest level among the EU member states, but is still among the countries with the highest primary energy use per capita. Not least because of that, increasing energy efficiency is important and it is part of the Swedish long term environmental objectives. Large potential for improving energy efficiency can be found in the building sector, mainly in the existing building stock but also in new constructions.Buildings hold high costs for construction, service and maintenance. Still, their energy efficiency and thermal performance are rarely validated after construction or renovation. As energy efficiency become an important aspects in building design there is a need for accurate tools for assessing the energy performance both before and after building construction. In this thesis criteria for energy efficiency in new residential buildings are studied. Several building design aspects are discussed with regards to final energy efficiency, energy supply-demand interactions and social aspects. The results of this thesis are based on energy modelling, energy measurements and one questionnaire survey. Several existing residential buildings were used as case studies.The results show that pre-occupancy calculations of specific final energy demand in residential buildings is too rough an indicator to explicitly steer towards lower final energy use in the building sector. Even post occupancy monitoring of specific final energy demand does not always provide a representative image of the energy efficiency of buildings and may result with large variation among buildings with similar thermal efficiency. A post occupancy method of assessing thermal efficiency of building fabrics using thermography is presented. The thermal efficiency of buildings can be increased by design with low shape factor. The shape factor was found to have a significant effect on the final energy demand of buildings and on the use of primary energy. In Nordic climates, atria in multi-storey apartment buildings is a design that have a potential to increase both energy efficiency (by lower shape factor) and enhance social interactions among the occupants.
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| 10. |
- Danielski, Itai, 1973-
(författare)
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Energy performance of residential buildings design
- 2016
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Ingår i: Society’s steering systems. - Östersund : Mid Sweden University. - 9789188025975 ; , s. 179-186
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Through the history of civilization, humans have built shelters to practice their social activities, while having protection against weather, wild animals, and other human beings. Over the course of time, vernacular dwellings have evolved to respond to climate challenges, available materials and cultural expectations in a given location. Such buildings include, e.g. the adobe house, the Inuit igloos in Greenland, and the open courtyard building design.Since the start of the postmodern architecture, in the middle of the 20th century, new technologies, new materials, and changes in societal structures have changed the way buildings have been designed and constructed. Modern lifestyle become more dependent on energy. For example Heating, Ventilation and Air Conditioning systems (HVAC) in buildings became widely used to improve indoor comfort. After the oil-supply crises in the middle of the 1970s, the connection between building design and the environment changed from just providing sufficient thermal comfort to promoting energy efficiency due to the awareness of the fact that natural resources are limited. That was the start of the sustainable architecture movement. It was during this time building regulations in many countries started to include aspects of energy efficiency. This chapter will discuss two aspects of building design and their effect on the overall energy efficiency of the building: the interior building design and the exterior building design.
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| 11. |
- Danielski, Itai, 1973-, et al.
(författare)
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Heated atrium in multi-story buildings : A design for better energy efficiency and social interactions
- 2013
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Konferensbidrag (refereegranskat)abstract
- The shape factor of a building expresses the ratio between the building’s thermal envelope area and its volume, or alternatively to its useful floor area. Buildings with lower shape factors will have lower heat losses through the thermal envelope and lower specific final energy demand. The shape factor of building could be reduced by a compact building shape design, and by increasing the volume of the building. However, the requirement for indoor natural light put a limit on the size of the building and therefore may limit the value of the shape factor. One possible solution to address this aspect is designing building with a heated atrium.An atrium is a large enclosed space within a building, and may have a glazed roof. In a multi-story apartment building an atrium has the potential to increase the social interaction between the residents and, with the right design, at the same time reduce the heating demand of the building due to lower building shape factor. However, the use of atrium in residential buildings in Nordic countries has not yet gained popularity.In this paper the impact of the heated atrium building with cylindrical shape design on the specific final energy is investigated by comparing such building design to conventional design buildings with similar floor area. The Nydalahuset project, in city Umeå in the north of Sweden, which is a multi-story residential building with a heated atrium, is used as a case study to investigate the affect of the atrium on the social interaction among the building occupants.The results show that heated atrium building with cylindrical shape design is a better energy efficient design than the conventional buildings. Such buildings in cold climate could help to reduce the heat losses through the thermal envelope and facilitate to achieve the passive house criteria. Moreover, the Nydalahuset project suggests that the atrium design could improve the social interaction of occupants in residential buildings.
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| 12. |
- Danielski, Itai, 1973-
(författare)
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How to lift students 10,000 meter up above ground
- 2018
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Konferensbidrag (refereegranskat)abstract
- Environment problems are complex and require a system integrated approach, which involves different time scales and spatial resolution. Yet, many parts of the world are facing similar environmental challenges. Therefore, mankind needs to share knowledge and work together across physical borders, language barriers, and cultures differences.In our International Master's programme in Ecotechnology and Sustainable Development in Mid-Sweden University, we use new pedagogical technologies to bring students from different nations and cultures together and reinforce teamwork. All courses in the program are in English and students can choose to be present in the classroom or to stream lectures online in real-time. Via special software, teachers are able to communicate both with classroom and distance students simultaneously. This provides flexibility to access graduate level courses in environmental science from anywhere in the world.Still, we aim to unify the students as one group. To achieve that, all students are invited to a joint activity in a mountain area nearby the university for one week. There, they are performing different field measurements, which help them to know each other and develop a group feeling. Group assignments are red thread throughout the program. It enhances student communication and exchange of information from different parts of the world.The overall aim of the master programme is to “lift” the students 10.000 meter up above ground. From that height they can see forests, water systems, cities and societies and not individual trees, streams, buildings or people. Only then they can understand how environmental issues are related and could be analyzed. This is achieved by introducing a variety of advanced system modelling tools, policy instruments, impact strategies, and communication skills. After graduation, the students are able to assist policy makers to resolve a variety of integrated environmental issues with ecological, social, cultural and economic perspectives.
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| 13. |
- Danielski, Itai, 1973-
(författare)
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Improving indoor comfort in elementary school environment in North of Sweden with green plants ‐ experimental study
- 2021
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Ingår i: Accelerating the progress towards the 2030 SDGs in times of crisis. - Östersund : Mid Sweden University. - 9789189341173 ; , s. 1214-1214
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Konferensbidrag (refereegranskat)abstract
- Poor indoor environment in primary schools in Sweden seems to be a problem in many municipalities in Sweden. In a report from the Swedish Public Health Agency, it is estimated that 40 percent of schools have complaints about air quality. The causes of the problems are poor ventilation, high humidity, changes that where made to the buildings, and high density of pupils in the classrooms. Improving indoor air by improvement of ventilation systems can be too costly for municipalities. In this project, we have looked at whether an installation of a large number of green plants in classrooms could change that, and even reduce energy use. There is research that shows that we feel both physically and mentally better if we are surrounded by green plants. Physically, because they can purify the air and convert carbon dioxide to oxygen. In addition, they increase the humidity and regulate the temperature. Mentally, perhaps because we are part of nature and have lived in it most of human history. The case study in this project was an elementary school located in a small rural community in the northern part of Sweden. A total of 350 green plants were installed in four plant‐stands distributed in 2 different eighth grade classrooms with about 25 students in each. A similar adjacent classroom (ninth grade) was used as a reference object without green plants. The plant‐stands were designed by industrial design students at Mid Sweden University and would result in functional prototypes with automatic irrigation. The project lasted for two semesters, the autumn semester 2019 and the spring semester 2020. Measurements of the indoor temperature showed that the green plants contribute to a more stable temperature and can even increase the temperature slightly, which can be used to reduce the need for heat. The effects on humidity were only higher in the classrooms with plants during the night when the ventilation flow was low. The carbon dioxide levels in the classrooms with the plants were 10% lower during education time compared to the control classroom, which indicates that green plants could be used to reduce the ventilation air flow and thereby reduce heat losses from exhaust air flow. The amount of airborne particles was already low and no change could be observed after the installation of the plants.
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| 14. |
- Danielski, Itai, 1973-, et al.
(författare)
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In situ measurements of thermal properties of building fabrics using thermography under non-steady state heat flow conditions
- 2018
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Ingår i: Infrastructures. - : MDPI. - 2412-3811. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- This study describes a quantitative method using thermography to measure the thermal properties of building fabrics that are subjected to non-steady state heat flow due to consistently changing meteorological conditions. The method includes two parts. First, the convection heat transfer coefficient is measured by thermography and heat flux meters on a small segment of the examined building fabric with uniform surface temperature. Then, thermal properties of large building fabrics are evaluated by thermography. The two parts are measured simultaneously. The method was tested on 140/160/190 mm thick massive laminated spruce timber walls of a test facility cabin located in Östersund, Sweden. The results varied by only a few percent in comparison to validation measurements performed with heat flux meters and in comparison, to values from the literature. Due to rapid changes in weather conditions the measured values had large disparity, but still a linear regression with low confidence interval was obtained. Obtaining an accurate value of convection heat transfer was important for achieving high measurement accuracy and, therefore, the value of this parameter should be measured. Other important factors to consider are solar radiation, reflected infrared (IR) radiation from nearby objects and the number of thermal images.
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| 15. |
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| 16. |
- Danielski, Itai, 1973-, et al.
(författare)
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Systems effecting systems when managing energy resources
- 2013
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Konferensbidrag (refereegranskat)abstract
- Managing natural resources to minimize impacts driving global change requires system understanding. The ecological systems are affected by different human interventions e.g. through the use of natural resources and generation of emissions. The ‘ecological footprint’ of a provided service can differ significantly according to both the choice of technology as well as the interactions of a specific technology option within the overall technical systems. Such interactions within the technical system may have significant impact on the modeling results regarding ecological consequences for a specific technical option. These interactions are important to understand for good decision support and policy making in the context of global change. This will be illustrated by the case of using air-to-air heat pumps for space heating in Sweden.In recent years, air-to-air heat pumps have been the most sold technology for space heating in residential buildings in Sweden. Newly produced air-to-air heat pumps can provide heat energy from outdoor air at temperature as low as -20°C. A drawback of air-to-air heat pumps is their reduction in efficiency as the outdoor air become colder. In this study, the use of air-to air heat pumps is compared with other commercial technologies integrated in the Swedish and European energy system.Results show that although air-to-air heat pumps are presently very cost effective for the end user and give relatively low final energy demand for space heating by comparison to other commercial technologies, seen integrated in the Swedish and European energy system, air-to-air heat pump are inferior regarding the use of resources and securing peak load power demand. Thus, by modeling the performance of air-to-air heat pumps first by including only its interaction with the building and than by including its interaction with the larger energy system suggest that there is presently a micro economic driver for the local investor pointing in the opposite direction regarding management of natural energy resources compared to what would be desirable in the context of global change.
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| 17. |
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| 18. |
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| 19. |
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| 20. |
- Fogelström, Frej, et al.
(författare)
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A review of possibilities and challenges of pit thermal energy storages in Swedish district heating networks
- 2024
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Ingår i: ISEC 2024. - : AEE – Institute for Sustainable Technologies.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of pit thermal energy storages (PTES) enables higher solar fraction in district heating networks by counteracting the mismatch between heat demand and production in solar district heating (SDH) installations. Capital costs linked to land areas with site-specific geological conditions are the deciding factors for PTES constructions. This study investigates non-technical and technical factors for the implementation of PTES in Swedish district heating networks. Having several SDH and PTES installations in operation the country of Denmark is used as a reference. This study, based on literature review, discusses the drivers and challenges for the use of PTES in district heating networks.
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| 21. |
- Forsström, Stefan, 1984-, et al.
(författare)
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Collecting Indoor Environmental Sensor Values for Machine Learning Based Smart Building Control
- 2021
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Ingår i: IoTaIS 2020 - Proceedings. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728194486 ; , s. 37-43
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Konferensbidrag (refereegranskat)abstract
- This research presents a solution for collecting indoor environmental sensor values and how the gathered sensor values then could be used for green building certification and in turn also machine learning based smart building control. We have created and implemented a proof of concept system consisting of a sensor collecting device using off the shelf hardware to complement the existing sensor information from buildings, as well as a cloud system for persistently storing this data for later usage. We have measured and evaluated our implemented system for our envisioned scenarios. In which we could observe that our proof-of-concept could scale to handle almost four sensor value updates per second at maximum stress, as well as having a latency for uploading a sensor value from our sensor of about 130 ms. Finally, we present our future and ongoing work based on these results which outlines our work for smart building control, green building certification, and the energy signature of buildings.
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| 22. |
- Haller, Henrik, 1977-, et al.
(författare)
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Towards a Resilient and Resource-Efficient Local Food System Based on Industrial Symbiosis in Härnösand : A Swedish Case Study
- 2022
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- The endeavour to align the goals of the Swedish food strategy with the national environmental quality objectives and the 17 global SDGs, presents an extraordinary challenge that calls forsystemic innovation. Industrial symbiosis can potentially provide the means for increasing sustainable food production, using locally subexploited resources that can reduce the need for land, agro-chemicals, transport and energy. This case study of the municipality of Härnösand, aims to assess opportunities and challenges for using waste flows and by-products for local food production, facilitated by industrial symbiosis. A potential symbiotic network was developed during three workshops with the main stakeholders in Härnösand. The potential of the COVID-19 pandemic to instigate policy changes, behavioural changes and formation of new alliances that may catalyse the transition towards food systems based on industrial symbiosis is discussed. The material flow inventory revealed that many under exploited resource flows were present in quantities that rendered them commercially interesting. Resources that can be used for innovative food production include, e.g., lignocellulosic residues, rock dust, and food processing waste. The internalised drive among local companies interested in industrial symbiosis and the emerging symbiotic relations, provide a fertile ground for the establishment of a local network that can process the subexploited material flows. Although there are multiple challenges for an industrial symbiosis network to form in Härnösand, this study shows that there is a significant potential to create added value from the region’s many resources while at the same time making the food system more sustainable and resilient, by expanding industrial symbiosis practices.
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| 23. |
- Mikaelsson, Lars-Åke, et al.
(författare)
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Sustainable building engineering by blended learning
- 2020
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Ingår i: IOP Conference Series. - : Institute of Physics Publishing (IOPP).
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Konferensbidrag (refereegranskat)abstract
- The sustainable building engineering education at Mid Sweden University has since it started 1994 a strong focus on sustainable building. It is also committed to be a pilot case for blended learning. All courses in the building engineering program were from the autumn 2012 adapted to a blended learning concept. That means that all courses are available in an integrated mix of ordinary campus and online distance education in real time. Blended learning is a way of taking in account different needs concerning student study situation. Adult students, bound with house and families, often prefer more distance education while younger students need more campus education. The results of the case study show that blended learning attracts more students, and allows students with different backgrounds to study and gives a more solid base of students for the program. It also allows a more flexible way of allocating resources by integrating two previous modes of delivery for the same program. This provides an education with a well thought through quality assurance. Another strength of blended learning is the possibility to connect individual students to a larger collective of students, making it possible for them to relate to and learn with and from others by social interactions that are difficult to achieve in solely online education. The pilot case is so far limited to the sustainable building engineering program but in a next stage the concept is planned to be spread to other engineering programs and other education programs at Mid Sweden University.
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| 24. |
- Truong, Nguyen Le, 1976-, et al.
(författare)
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Effects of solar thermal energy on district heating systems : the case of parabolic trough collectors in a high-latitude region
- 2024
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Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902.
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates primary energy use and CO2 emission reduction potential resulting from the integration of solar thermal heating in biomass-based district heating systems in high-latitude regions. A newly commissioned solar thermal system based on parabolic trough collectors for an existing district heating network in Häarnösand, Sweden, is used as a case study, and its hourly one-year measured data are used as inputs for the analysis. The changes in operation and fuel use for local district heat production are extended to a regional context, considering the short- and long-term perspectives of the energy system. The results show that during the studied period, the solar water heating system provided 335 MWh of heat to the existing district heating system with a supply/return temperature of approximately 80/45 °C. Consequently, 339–382 MWh of biomass fuel consumption could be reducedannually with such an installation, depending on the district heat production technologies being substituted. An annual CO2 reduction of 65.3–189 tons can be achieved in an overall energy system perspective when the saved biomass substitutes fossil fuels. The reduction of CO2 emission depends on the fuels being substituted and energy conversion technology.
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