| 1. |
- Abugabbara, Marwan, et al.
(författare)
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A Novel Method for Designing Fifth-Generation District Heating and Cooling Systems
- 2021
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Ingår i: The 10th Cold Climate HVAC & Energy Conference 2021. - : EDP Sciences. - 2555-0403. ; 246
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Konferensbidrag (refereegranskat)abstract
- District heating and cooling systems have been undergoing continuous development and have now reached the fifth-generation. In this innovative technology, connected buildings share local excess energy that otherwise would be wasted, which consequently reduces primary energy demands and carbon emissions. To date, the issue of implementing fifth-generation district systems on existing buildings has received scant attention, and our research addresses this challenging gap by proposing a novel method for designing these systems. We first explain the possible thermal interactions between connected buildings, and then present an analytical solution for the network energy balance, pipe design, and the prediction of fluid temperature under a fixed temperature difference control strategy. The analytical solution was validated against numerical simulations performed on 11 existing buildings located in Lund, Sweden using Modelica models. A diversity index metric between heating and cooling demands was also included in these models to assess the efficiency of the district system in the building cluster. The results from the analytical and numerical solutions were in complete agreement since Modelica is an equation-based modelling language. The developed models pave the way towards future investigations of different temperature control strategies and new business models that arise from the shift to the fifth-generation.
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| 2. |
- Cabovska, Blanka, 1990, et al.
(författare)
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A study on the relationship between energy performance and IEQ parameters in school buildings
- 2021
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Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2555-0403 .- 2267-1242. ; 246
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Konferensbidrag (refereegranskat)abstract
- Over the last decades, strong focus has been placed on the energy efficiency of buildings; not least school buildings. Energy performance (EP) of buildings is nowadays in principle described by one single indicator based on purchased energy in kWh/year.m2. Another important building performance aspect is the indoor environmental quality. This study's overarching goal is to identify school buildings with a good balance between energy performance and indoor environment. Thus, this paper investigates possible correlations between information given in energy performance certificates (EPCs/e.g. energy use, year of construction, type of ventilation) and measured indoor environmental parameters. The work comprises investigation of approximately 20 school buildings with different ventilation systems in Gothenburg. In-situ investigations of the buildings' properties and ventilation systems were conducted. Indoor environmental parameters were recorded during one week in each classroom. In this paper, indoor temperature, absolute humidity added indoors and CO2 concentration data are compared with the corresponding school's energy performance data and ventilation type. Results suggest that mechanically ventilated buildings have clearer relationships between energy performance, building indicators and measured indoor environment. For buildings such as naturally ventilated, the relationships are usually weak, and the values spread over much wider ranges.
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| 3. |
- Jangsten, Maria, 1989, et al.
(författare)
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Field test of active night cooling supplied by district cooling in three commercial buildings
- 2021
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Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2555-0403 .- 2267-1242. ; 246
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Konferensbidrag (refereegranskat)abstract
- Several previous studies have investigated active night cooling strategies to reduce the peak cooling load in buildings, primarily by precooling the building by the ventilation air during the night. In this study, active night cooling is supplied by the use of district cooling, mainly for cooling buildings by hydronic cooling systems, such as chilled beam or fan coil systems, but potentially also to cool the ventilation air if the outdoor air temperature is above the supply air temperature setpoint. A field test with active night cooling by district cooling was conducted during the summer of 2020 in three commercial buildings located in Gothenburg, Sweden. The active night cooling strategy was implemented by changing the time schedule operation of the buildings’ chilled beam systems to twenty-four hours per day for the first half of the summer and changing back to regular time schedules for the second half. The results showed that active night cooling failed to reduce the hourly maximum cooling power. However, the peak cooling load, corresponding to the 100 hours with the highest cooling power, was reduced with 6.5% for one of the buildings. Active night cooling also reduced the daytime energy usage between 0.7 and 4.6%. The field test demonstrated that some buildings and associated cooling systems are more compatible for active night cooling than others. The test also showed it was possible to achieve some cooling power and energy reductions with simple measures. However, providing active night cooling supplied by district cooling will cause additional costs for the building owners unless it is incentivized by the district cooling provider.
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| 4. |
- Mattsson, Christian, et al.
(författare)
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Water damages in HVAC, tap water and sewage systems in cold climates
- 2021
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Ingår i: Cold Climate HVAC & Energy 2021. - : EDP Sciences. - 2555-0403. ; 246
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Konferensbidrag (refereegranskat)abstract
- Water damages in buildings in the Nordic countries results in costs amounting to several billion Euros each year as well as a great deal of unpleasantness. The vast majority of the water damages cost in Sweden is caused by leaks from buildings services in the form of piping such as tap water, sewage, drainage and heating, as well as through insufficiently waterproof layers in wet rooms. The economic potential for making measures to prevent water damages on building services and wet rooms is enormous and savings could be used for other sustainability measures in the built environment. The aim of this paper is to review statistics of damages caused in cold outdoor climates. This is done by an analyse of empirical damage statistics by a literature review of both scientific literature and in retrievable cases from practical experience. The result will be a help to focus on the right damage types in colder climate and will make a foundation for future research on how to prevent water damages. The cold climate in the Nordic countries seems to be a factor for the number of water damages due to freezing that are described in the statistics and it could be established that the impact of the climate should be considered and that it need to be constructed and designed for in a larger extent.
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| 5. |
- Oxenswärdh, Anette, phd, 1956-, et al.
(författare)
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Learning Processes towards Destination Development
- 2021
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Ingår i: E3S Web of Conferences. - Kaliningrad, Russia : EDP Sciences. - 2267-1242. ; 291, s. 06004-
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Forskningsöversikt (refereegranskat)abstract
- Sustainable development of tourist destinations is based on the key principles of sustainable development in general taking into consideration the characteristics of tourism as an activity, in particular. In the event that a tourist destination has an island location, this becomes an additional factor imposing even more stringent requirements for sustainable development due to even greater vulnerability of isolated ecological systems. At the same time, the human factor becomes decisive, because the development of a tourist destination depends on how the providers of tourism services comply with the principles of sustainable development. The purpose of our study is to identify the willingness to follow the principles of sustainable development of a tourist destinations among entrepreneurs providing tourism services, using innovative methods of problem-solving learning. During the study, the following methods were used: bibliographic, analytical, in-depth survey method, etc. The methodology implemented for this study was qualitative survey where students reflected on their learning processes. The results show the importance of university students cooperating with actors within tourist destination on both theoretical and practical issues of sustainability to develop the destination. This cooperation enables the most important learning outcomes for both parties on sustainability. Heterogeneity of the group, and methodology of Design Thinking increases the creativity in problem solving.
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| 6. |
- Rex, Emma, et al.
(författare)
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Exploring reluctance to circular business models – the case of light as a service
- 2021
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Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2267-1242.
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Konferensbidrag (refereegranskat)abstract
- Selling light as a service is one example of a service-based business model that could enable a more circular economy. However, despite a growing interest to become more circular, there is still hesitation among customers to change the way they meet their need for light. In an ongoing project, we explore this reluctance and seek to identify obstacles and driving forces for large customer organizations to buy light as a service. As a first step, an interview study and a workshop were made to identify current perceptions in a broad range of stakeholders including lighting manufacturers, suppliers of light as a service, light designers and architects, private and public customers, collaborative bodies, and sector organizations. The focus was on large customers (municipalities and property companies) and on indoor lighting in offices and schools in Sweden. Barriers and driving forces could be found in 5 categories: environmental impact, economic consequences, social effects, competence, and roles and responsibilities. The analysis points to the importance of increasing knowledge, reducing uncertainties, and creating trust between actors in the business ecosystem to decrease barriers to change. It also appears extending the value proposition and increasing emphasis on social and user benefits are key for light as a service to become competitive with traditional business models.
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| 7. |
- Wahlström, Åsa, et al.
(författare)
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Additional requirement to the Swedish nearly zero energy requirements
- 2021
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Ingår i: Cold Climate HVAC & Energy 2021. - : EDP Sciences. - 2555-0403. ; 246
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Konferensbidrag (refereegranskat)abstract
- This study has analysed which options would be appropriate to use as additional requirements to the main requirement of primary energy number in the new Swedish building regulations. The starting point is to ensure that buildings are built with good qualitative properties in terms of the building envelope so that low energy use can be maintained throughout the life of the building despite changes in installation systems or the building's occupancy. The additional requirements should aim to minimize energy losses, i.e., to ensure that the building's total energy demand is low. The following possible additional requirements have been examined: net energy demand, net energy demand for heating, heat power demand, heat loss rate and average heat transfer coefficient. In order to ensure that the additional requirements will work as desired and to explore possibilities with, and identify the consequences of, the various proposals, calculations have been made for four different categories of buildings: single-family houses, apartment buildings, schools and offices. The results show that the suggested option net energy demand will not contribute to any additional benefits in relation to primary energy number. The other options analysed have both advantages and disadvantages and it is difficult to find a single additional requirement that fulfils all the pre-set demands.
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