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  • 251.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Design strategies to minimise heating and cooling demands for passive houses under changing climate2017Inngår i: ECEEE 2017 Summer Study: Consumption, Efficiency & Limits, European Council for an Energy Efficient Economy (ECEEE), 2017, s. 1185-1195Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study, we analyse the heating and cooling demands of a multi-storey residential building version, designed to the passive house criteria in Southern Sweden and explore various design strategies to minimise these demands under different climate change scenarios. The analysis is performed for recent (1996–2005) and future climate periods of 2050–2059 and 2090–2099 based on the Representative Concentration Pathway scenarios, downscaled to conditions in South of Sweden. Design strategies include efficient household equipment and technical installations, bypass of ventilation heat recovery unit, window solar shading, building orientation, window size and properties, besides mechanical cooling. Results show that space heating demand reduces, while cooling demand increases as the risk of overheating under the future climate scenarios. The most important design strategies are efficient household equipment and technical installations, solar shading, bypass of ventilation heat recovery unit and window u-values and g-values. Total annual final energy demand decreased by 40–51 % and overheating is avoided or significantly reduced under the considered climate scenarios when all the strategies are implemented. Overall, the total annual primary energy for operating the building versions decreased by 49–54 % This study emphasises the importance of considering different design strategies and measures in minimising the operation energy use and the potential risks of overheating in low-energy residential buildings under future climate scenarios.

  • 252.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Effect of different frame materials on the primary energy use of a multi storey residential building in a life cycle perspective2019Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 185, s. 259-271Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Primary energy implications over the life cycle of a multi storey residential building with different building systems are explored here. The main structural materials of the buildings include precast concrete, cross laminated timber (CLT) and prefabricated timber modules (modular). The analysis covers energy and material flows from different life cycle phases of the building versions, designed to meet the energy performance of the Swedish building code (BBR) and passive house criteria. The CLT and modular buildings were found to result in lower production primary energy use and higher biomass residues compared to the concrete alternative. The heating value of the recoverable biomass residues from the production phase of the CLT building is significantly larger than the primary energy required for its production. Primary energy use for production and construction constitutes 20-30% and 36-47% of the total primary energy use for production, construction, space heating, ventilation and demolition for the BBR and passive buildings, respectively. Space heating with combined heat and power (CHP) and ventilation electricity for the BBR and passive building versions form 70-79% and 52-63%, respectively, of the total primary energy use for production, construction, space heating, ventilation and demolition for a lifespan of 80 years. The CLT and modular buildings give 20-37% and 9-17% lower total life cycle primary energy use, respectively, than the concrete alternative when space heating is from CHP. (C) 2019 Elsevier B.V. All rights reserved.

  • 253.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Effects of different insulation materials on primary energy and CO2 emission of a multi-storey residential building2014Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 82, s. 369-377Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, we analyzed the implications of various insulation materials on the primary energy and CO2emission for material production of a residential building. We modeled changes to the original design ofthe building to achieve reference buildings to energy-efficiency levels of the Swedish building code of2012 or the Swedish Passivhus 2012 criteria. We varied the insulation materials in different parts of thereference buildings from mineral rock wool to glass wool, cellulose fiber, expanded polystyrene or foamglass. We compared the primary energy use and CO2emission from material production of functionallyequivalent reference and optimum versions of the building. The results showed a reduction of about 6–7%in primary energy use and 6–8% in CO2emission when the insulation material in the reference buildingsis changed from rock wool to cellulose fiber in the optimum versions. Also, the total fossil fuel use for onlyinsulation material production was reduced by about 39%. This study suggests that enhancing materialproduction technologies by reducing fossil fuel-use and increasing renewable energy sources, as wellas careful material choice with renewable-based raw materials can contribute significantly in reducingprimary energy use and GHG emission in the building sector.

  • 254.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Energy use implications of different design strategies for multi-storey residential buildings under future climates2017Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 138, s. 846-860Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of climate change on the final and primary energy use of versions of a multi-storey residential building have been analysed. The building versions are designed to the Swedish building code (BBR 2015) and passive house criteria (Passive 2012) with different design and overheating control strategies under different climate scenarios. Future climate datasets are based on Representative Concentration Pathway scenarios for 2050–2059 and 2090–2099. The analysis showed that strategies giving the lowest space heating and cooling demands for the Passive 2012 building version remained the same under all climate scenarios. In contrast, strategies giving the lowest space heating and cooling demands for the BBR 2015 version varied, as cooling demand became more significant under future climate scenarios. Cooling demand was more dominant than heating for the Passive 2012 building version under future climate scenarios. Household equipment and technical installations based on best available technology gave the biggest reduction in total primary energy use among considered strategies. Overall, annual total operation primary energy decreased by 37–54% for the building versions when all strategies are implemented under the considered climate scenarios. This study shows that appropriate design strategies could result in significant primary energy savings for low-energy buildings under changing climates.

  • 255.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Impacts of parameter values interactions on simulated energy balance of residential buildings2017Inngår i: 11th Nordic Symposium on Building Physics, NSB2017, 11-14 June 2017, Trondheim, Norway / [ed] Stig Geving, Berit Time, Elsevier, 2017, Vol. 132, s. 57-62Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study we use dynamic simulation to explore the interactive impacts of different uncertain parameter values in energy balance modelling of existing and improved variants of a Swedish multi-storey residential building. We modelled variations as well as interactive influence of different simulation assumptions and parameters encompassing outdoor microclimate, building thermal envelope and technical installations including household equipment. The results indicate that the interactive influence of the parameters on calculated space heating of buildings seems to be small and relatively more evident for a low-energy building than for a conventional building. The influence of the interactions between the parameter combinations becomes more evident as several parameters are varied simultaneously. The results also indicate that calculated space heating demand of a building is noticeably influenced by how heat gains from household equipment and technical installations are modelled. The calculated final energy for space heating for the analysed building versions varied between 13-43% depending on the energy efficiency levels for household equipment and technical installations as well as their interactions with other parameter values variations. This study shows the importance of appropriate input parameters and assumptions for building energy balance calculation.

  • 256.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Primary energy implications of different design strategies for an apartment building2016Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 104, s. 132-148Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, we explored the effects of different design strategies on final and primary energy use for production and operation of a newly constructed apartment building. We analysed alternatives of the building “As built” as well as to energy efficiency levels of the Swedish building code and passive house criteria. Our approach is based on achieving improved versions of the building alternatives from combination of design strategies giving the lowest space heating and cooling demand and primary energy use, respectively. We found that the combination of design strategies resulting in the improved building alternatives varies depending on the approach. The improved building alternatives gave up to 19–34% reduction in operation primary energy use compared to the initial alternatives. The share of production primary energy use of the improved building alternatives was 39–54% of the total primary energy use for production, space heating, space cooling and ventilation over 50-year lifespan, compared to 31–42% for the initial alternatives. This study emphasises the importance of incorporating appropriate design strategies to reduce primary energy use for building operation and suggests that combining such strategies with careful choice of building frame materials could result in significant primary energy savings in the built environment.

  • 257.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Primary energy implications of different wall insulation materials for buildings in a cold climate2014Inngår i: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014 / [ed] Yan, J; Lee, DJ; Chou, SK; Desideri, U; Li, H, Elsevier, 2014, Vol. 61, s. 1204-1207Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study, we investigate the influence of different external wall insulation systems on the primary energy use of a case study building in southern Sweden. We vary the insulation material of the external walls from rock wool to glass wool or expanded polystyrene (EPS) to achieve different energy-efficiency standards of the building. We apply appropriate thicknesses of the different insulation materials to achieve similar thermal transmittance (U-value) of the external walls under the different energy-efficiency standards. The different options are based on the same architectural design. We calculate and compare the primary energy for production of the insulation materials and for operation of the buildings. Rock wool gives the lowest primary energy for production, followed by glass wool and EPS for each energy efficiency standard, although the difference between rock wool and glass wool is small.

  • 258.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Primary energy and CO2 emissions implications of different insulation, cladding and frame materials for residential buildings2019Inngår i: SBE 19 - Emerging Concepts for Sustainable Built Environment 22–24 May 2019, Helsinki, Finland, Institute of Physics (IOP), 2019, Vol. 297, nr 1, s. 1-11, artikkel-id 012020Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study, we analyse and compare the primary energy use and carbon dioxide (CO2) emissions associated with different insulation, cladding and frame materials for a constructed concrete frame multi-storey residential building in Sweden. Our approach consists of identifying individual materials giving the lowest primary energy use and CO2 emissions for each building envelope part and based on that, modelling different material combinations to achieve improved alternatives of the concrete frame building with the same operation energy use based on the Swedish building code or passive house criteria. We analyse the complete materials and energy chains, including material losses as well as conversion and fuel cycle losses. The analysis covers the primary energy use to extract, process, transport, and assemble the materials and the resulting CO2 emissions to the atmosphere. The results show wide variations in primary energy and CO2 emissions depending on the choice of building envelope materials. The materials for external walls contribute most to the primary energy and CO2 emissions, followed by foundation, roof and external cladding materials. The improved building alternatives with wood construction frames, wood external cladding, expanded polystyrene as foundation insulation and cellulose insulation in the external walls and roof result in about 36 - 40% lower production primary energy use and 42 - 49% lower CO2 emissions than the improved concrete alternative when achieving the same thermal performance. This study suggests that strategies for low-energy buildings should be combined with resource-efficient and low carbon materials in the production phase to mitigate climate change and achieve a sustainable built environment. © 2019 IOP Publishing Ltd. All rights reserved.

  • 259.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Primary energy implications of different external wall configurations for residential buildings2014Inngår i: World Sustainable Building 2014, Barcelona Conference: Sustainable Building:Results ; Are We Moving as Quickly as We Should? It's up to us!, GBCe , 2014Konferansepaper (Fagfellevurdert)
  • 260. Tommerup, H.
    et al.
    Vanhoutteghem, L.
    Svendsen, S.
    Paiho, S.
    Ala-Juusela, M.
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Haavik, T.
    Aabrekk, S.
    Existing sustainable renovation concepts for single-family houses2010Inngår i: SB10, Sustainable Community, Espoo, Finland, September 22-24, 2010, 2010Konferansepaper (Fagfellevurdert)
  • 261. Tommerup, Henrik
    et al.
    Vanhoutteghem, Lies
    Svendsen, Svend
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Haavik, Trond
    Aabrekk, Synnöve
    Paiho, Satu
    Ala-Juusela, Mia
    Existing sustainable renovation concepts2010Rapport (Annet vitenskapelig)
    Fulltekst (pdf)
    FULLTEXT01
  • 262.
    Tommerup, Henrik
    et al.
    Technical University of Denmark, Denmark.
    Vanhoutteghem, Lies
    Technical University of Denmark, Lyngby, Denmark.
    Svendsen, Svend
    Danish Technical University, Lyngby, Denmark.
    Mahapatra, Krushna
    Växjö universitet, Fakulteten för matematik/naturvetenskap/teknik, Institutionen för teknik och design.
    Gustavsson, Leif
    Växjö universitet, Fakulteten för matematik/naturvetenskap/teknik, Institutionen för teknik och design.
    Haavik, Trond
    Segel As, Norway.
    Aabrekk, Synnøve
    Segel As, Norway.
    Paiho, Satu
    VTT, Espoo, Finland.
    Ala-Juusela, Mia
    VTT, Espoo, Finland.
    Analysis of promising sustainable renovation concepts, Deliverable D1.2 of the project Successful Sustainable Renovation Business for Single-Family Houses - SuccessFamilies.2009Rapport (Annet vitenskapelig)
  • 263.
    Tommerup, Henrik
    et al.
    Technical University of Denmark, Denmark.
    Vanhoutteghem, Lies
    Technical University of Denmark, Denmark.
    Svendsen, Svend
    Technical University of Denmark, Denmark.
    Mahapatra, Krushna
    Mid Sweden University, Sweden.
    Gustavsson, Leif
    Mid Sweden University, Sweden.
    Haavik, Trond
    Segel AS, Norway.
    Aabrekk, Synnøve
    Segel AS, Norway.
    Paiho, Satu
    VTT Technical Research Centre of Finland, Finland.
    Ala-Juusela, Mia
    VTT Technical Research Centre of Finland, Finland.
    Existing sustainable renovation concepts, Deliverable D1.1: Successful Sustainable Renovation Business for Single-Family Houses - SuccessFamilies2010Rapport (Annet vitenskapelig)
    Abstract [en]

    The Nordic single-family house renovation market is dominated by a craftsman based approach with individual solutions, traditional warehouses ”do-it-yourself-shops” and some actors marketing single products. To speed up the implementation of sustainable renovation of single-family houses there is a great need for full-service packages including consulting, contract work, follow-up, financing and operation and maintenance. There are few Nordic examples of such service models for renovation of single-family houses which entered the market recently. The success of these concepts is yet to be evaluated.

    One successful full-service package described in the report is a campaign by an energy company in Sweden who convinced 78% of 456 owners of houses with resistance heaters to connect to its biomass based district heating network. The campaign was successful because of its package offer and information provision with emphasis on economic aspects and functional reliability.

    The existing technical renovation concepts, typically focussing on application of only a few of the available technical solutions, have not been successful in realizing large scale energy efficiency gains. Renovation of single-family houses might be carried out based on design solutions with good combinations of the possible range of technical solutions including e.g. “passive (insulation) measures” and “solar measures” in order to reach a low primary energy level. Key aspects of reaching a low primary energy level in connection with renovation are described in the form of typical energy renovation measures and technical principles of low energy renovation including recommended extent of measures.

    Full service and technical renovation concepts should make it easy, simple and secure for the consumer to invest in a low energy renovation of their house. The building sector needs easy to use knowledge and initiatives which ensures that they can offer solutions which fulfil the demand for quality, economy and a simple process. To speed up the implementation of sustainable renovation of single-family houses, society needs to stimulate the process including better incentives structures, e.g. increased tax on energy and/or subsidy programmes. Combined with an outlook for rising global energy prices, sustainable renovation of single-family houses then has the potential to become an important market area in the future.

  • 264.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Effects of energy efficiency measures in district-heated buildings on energy supply2018Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 142, s. 1114-1127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study we estimate the final and primary energy savings for different energy efficiency measures in a multi-apartment building when heated by small-, medium- or large-scale district-heat production systems (DHSs). The small-scale system is based on heat-only boilers, whereas the other two also include cogeneration of district heat and electricity. In the systems with cogeneration units, a change in building's heat demand may influence cogenerated electricity and hence the overall power system. For the building analyzed, the estimated annual total final heat and electricity savings were 136 (54%) and 30 MWh (52%), respectively, giving total annual primary energy savings of 177–289 MWh. This varies as the ratio of primary and final heat savings depends on the type of energy efficiency measure and the energy supply. For the same heat savings measure, a system with a heat-only boiler gave the highest primary energy savings, whereas a system based mostly on cogeneration of district heat and electricity in combination with averaged-efficiency standalone power plants gave the lowest primary energy savings. When the energy supply is based on energy-efficient renewable-based system, the differences in primary energy savings between large- and small-scale DHSs are minor for the same energy efficiency measure.

  • 265.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Effects of energy-efficiency measures and climate change mitigation policy instruments on primary energy use in district-heated buildings2013Inngår i: ECEEE Summer Study proceedings: rethink, renew, restart, European Council for an Energy Efficient Economy (ECEEE), 2013, s. 515-522Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The effectiveness of energy-efficiency measures in a district-heated building can be complex, as it depends on how energy is produced and used. In this study, a primary energy analysis was conducted based on a case study of a Swedish apartment building that is connected to a district heat production system while considering different climate change mitigation policy instruments including carbon taxes corresponding to Social cost-Business-as-usual or Social cost-550 ppm scenarios. The potential to reduce final heat and electricity demands by different energy-efficiency measures was analyzed for the building used in the case study. The impacts of reducing final energy from the different energy-efficiency measures and the climate change policy instruments on primary energy use and cost of district heat production were investigated using a systems analysis approach. We discussed the importance of analyzing the demand and supply sides and their interaction to minimize primary energy use in district-heated buildings. We showed that climate change mitigation policy instruments have a minimal effect on heat production costs for optimally designed district heat production. The primary energy savings for the energy-efficiency measures depend partly on the characteristics of the district heat production system, which is influenced by the policy instruments.

  • 266.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Effects of heat and electricity saving measures in district-heated multistory residential buildings2014Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 118, s. 57-67Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of heat and electricity saving measures in district-heated buildings can be complex because these depend not only on how energy is used on the demand side but also on how energy is provided from the supply side. In this study, we analyze the effects of heat and electricity saving measures in multistory concrete-framed and wood-framed versions of an existing district-heated building and examine the impacts of the reduced energy demand on different district heat (DH) production configurations. The energy saving measures considered are for domestic hot water reduction, building thermal envelope improvement, ventilation heat recovery (VHR), and household electricity savings. Our analysis is based on a measured heat load profile of an existing DH production system in Växjö, Sweden. Based on the measured heat load profile, we model three minimum-cost DH production system using plausible environmental and socio-political scenarios. Then, we investigate the primary energy implications of the energy saving measures applied to the two versions of the existing building, taking into account the changed DH demand, changed cogenerated electricity, and changed electricity use due to heat and electricity saving measures. Our results show that the difference between the final and primary energy savings of the concrete-framed and wood-framed versions of the case-study building is minor. The primary energy efficiency of the energy saving measures depends on the type of measure and on the composition of the DH production system. Of the various energy saving measures explored, electricity savings give the highest primary energy savings for the building versions. In contrast to the other heat savings measures, VHR gives lower primary energy savings as it also increases electricity demand. Primary energy savings for the building versions are lower where the minimum-cost DH production system includes cogeneration unit compared to where the minimum-cost DH production system comprises heat-only boilers. The primary energy savings are mainly from peak and medium-load boilers even though these production units cover a small share of the total DH production. This study shows that it is essential to consider the interaction between end-use energy saving measures and supply systems for district-heated buildings, to estimate the primary energy efficiency of energy saving measures.

  • 267.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Final and primary energy use for heating new residential area with varied exploitation levels, building energy performance and district heat temperatures2019Inngår i: Innovative Solutions for Energy Transitions / [ed] Jinyue Yan, Hong-xing Yang, Hailong Li, Xi Chen, Elsevier, 2019, Vol. 158, s. 6544-6550Konferansepaper (Fagfellevurdert)
    Abstract [en]

    There is great potential to build new energy-efficient building blocks in combination with efficient energy supply systems. Such a development will contribute to achieve national energy and climate goals as well as the overall aim for a sustainable development. Here, we analyze final and primary energy use for heating a new residential area by using district-heating. The area, located in Växjö, in south Sweden has potentially varied land exploitation levels, energy performance of buildings and district heat supply/return temperatures. The results show that the district heating demand will be reduced by about 52-56% if buildings in the area meet the Swedish passive house criteria instead of the Swedish building code. The exploitation levels of construction in the area strongly influence the total heating demands. A dense instead of a low exploitation will increase the area’s heating demand more than four times. But, the heat demand density of the residential area has quite a small impact on the total heat losses of the distribution network in contrast to changed supply and return temperatures. The distribution heat losses could be reduced by up to 50% with lower supply/return temperatures. However, a reduction of district heat supply/return temperatures to 50/20oC increases electricity use for boosting hot water temperature to avoid the risk of legionella bacteria. This causes a shift from district heat production to electricity production and increases the primary energy use. The results of this study can be used for further considerations of costs and benefits of energy supply options for new residential areas.

  • 268.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Renewable-based heat supply of multi-apartment buildings with varied heat demands2015Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 93, s. 1053-1062Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigates the cost and primary energy use to heat an existing multi-apartment building in Sweden, before and after deep energy efficiency renovation, with different types of renewable-based systems. District heating systems of different scales as well as local heat production based on bioelectric boilers, ground-source bioelectric heat pumps and wood pellet boilers with or without solar heating are considered. The annual energy demand of the building, calculated hour by hour, with and without energy efficiency improvements, are matched against the renewable-based heat supply options by techno-economic modeling to minimize cost for each considered heat supply option. The results show that the availability of heating technologies at the building site and the scale of the building's heat demand influence the cost and the primary energy efficiency of the heating options. District heat from large-scale systems is cost efficient for the building without energy-efficiency improvement, whereas electric heat pumps and wood pellet boilers are more cost efficient when implementing energy-efficiency improvement. However, the cost difference is small between these alternatives and sensitive to the size of building. Large-scale district heating with cogeneration of power is most primary energy efficient while heat pumps and medium-scale district heating are nearly as efficient.

  • 269.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Climate effects of biomass use in integrated energysystems2017Inngår i: ECEEE Summer Study proceedings 2017, European Council for an Energy Efficient Economy (ECEEE), 2017, s. 911-920Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Biomass is a key resource in a society based on renewable energy, but is a limited resource and the use of biomass in one sector will influence its availability for other sectors. The global energy system is heavily dependent on fossil fuels, and the climate impacts of CO2 occur regardless of the source of emissions. As a result, the climatic effects of biomass use in an energy system depend largely on which biomass feedstock and bioenergy pathway is being used, and what type of fossil fuel pathway is being replaced. In this study, we evaluate the CO2 emissions and climate effects of woody biomass and fossil fuel use. We analyse the potential production of electricity, heat or transport distance when using one kWh of woody biomass and fossil energy system designed to provide the same service to society as the most energy efficient bioenergy systems. The fuel cycle inputs are included in the analyses and are based on different state-of-the art as well as emerging technologies for energy conversion. We quantify the primary energy use and annual CO2 emission of different bioenergy and fossil alternatives. We then calculate the cumulative CO2 emission and climate effects in terms of cumulative radiative forcing for the fossil and bioenergy systems. The results show that primary energy use, CO2 emission, and cumulative radiative forcing vary strongly between the studied alternatives. The use of bioelectricity and electric vehicles instead of biomotor fuel-based vehicles gives about twice the transport distance per unit of consumed woody biomass. Integrated energy systems that supply a package of energy services including electricity, heat and transport distance reduce the primary energy use and increase the climate benefits of woody biomass. The replacement of coal for heat and electricity production by the here studied woody biomass gives large climate benefits immediately.

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  • 270.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Co- and polygeneration of district heat, electricity and/or biomotor fuels in renewable-based energy systems2019Inngår i: The 14th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES 2019), Dubrovnik, Croatia, October 1-6, 2019, 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The co- or polygeneration benefits of energy products from a system vary and depends on several factors including how each individual product is otherwise produced and used. In a Nordic renewable based energy system, district heating system using woody biomass could be used for the production of several products and for the integration of electricity, heat and transportation sectors. Energy-efficient systems for the production of different wood based energy services, including efficient end-use system, will reduce the need for woody biomass that could be used in other sectors with less other renewable alternatives including aviation, shipping and material production. However, the scale and the annual variation of heat demands for single district heating systems are key factors that influence co- or polygeneration benefits of such systems. In this study, we analyse district heating systems with annual heat demands between 100 to 1000 GWh. Several technical configurations of co- or polygeneration of heat, electricity and/or biomotor fuels are analyzed, considering different standalone production options, woody biomass fuel prices and integration costs of intermittent energy resources. The development of several state-of-the-art technologies shows that there are co- or polygeneration benefits in district heating systems. System configuration varies with the scales of district heat production as does the use of biomass to generate the same amount of products and both depend on the context of the overall energy system. Electric-based solution for transportation as well as electric-based option for small-scale district heating systems together with cogeneration of heat and electricity in larger district heating system reduce the use of biomass and help to integrate wind power in the overall energy system. Further studies are needed to understand how deep energy-renovation of buildings may influence the configuration of co- or polygeneration system in district heating systems and the potential saving of woody biomass.

  • 271.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Cost and primary energy efficiency of small-scale district heating systems2014Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, nr Part 1 Special Issue, s. 419-427Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Efficient district heat production systems (DHS) can contribute to achieving environmental targets and energy security for countries that have demands for space and water heating. The optimal options for a DHS vary with the environmental and social-political contexts and the scale of district heat production, which further depends on the size of the community served and the local climatic conditions. In this study, we design a small-scale, minimum-cost DHS that produces approximately 100 GWhheat per year and estimate the yearly production cost and primary energy use of this system. We consider conventional technologies, such as heat-only boilers, electric heat pumps and combined heat and power (CHP) units, as well as emerging technologies, such as biomass-based organic Rankine cycle (BORC) and solar water heating (SWH). We explore how different environmental and social-political situations influence the design of a minimum-cost DHS and consider both proven and potential technologies for small-scale applications. Our calculations are based on the real heat load duration curve for a town in southern Sweden. We find that the district heat production cost increases and that the potential for cogeneration decreases with smaller district heat production systems. Although the selection of technologies for a minimum-cost DHS depends on environmental and social-political contexts, fewer technical options are suitable for small-scale systems. Emerging technologies such as CHP-BORC and SWH improve the efficiency of primary energy use for heat production, but these technologies are more costly than conventional heat-only boilers. However, systems with combined technologies are less sensitive to fluctuations in fuel prices, specifically the SWH system, compared to technologies based on conventional fuels. Furthermore, increased market penetration of SWH will reduce the investment costs of such systems and, along with expected fuel price increases, using SWH may be cost-efficient in DHSs.

  • 272.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Costs and primary energy use of heating new residential areas with district heat or electric heat pumps2019Inngår i: Innovative Solutions for Energy Transitions: Proceedings of the 10th International Conference on Applied Energy (ICAE2018) / [ed] Prof. J.Yana, Prof. H.Yang, Dr. H.Li, Dr. X.Chen, Elsevier, 2019, Vol. 158, s. 2031-2038Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The choice of a heat supply option in new residential areas depends on various factors including available local energy resources and the scale and density of the heat demand in the areas. Here, we study costs and primary energy use of using district heat (DH) and ground-source electric heat pump (EHP) for heating a residential area being developed. We consider different architecture layouts and exploitations of the area along with different building energy efficiency standards which give different heat demand densities and profiles for this residential area. The analysis shows that for existing fuel-based energy supply systems, using DH is more primary energy efficient than using EHP to supply heat to the new residential area. However, if the future production of marginal electricity is based on state-of-the art technologies utilizing renewable energy resources, using EHP can be more primary energy efficient than using DH. The initial investment costs are much lower for options using DH than for options using ground-source EHP for the different exploitation alternatives. Also, the marginal heat cost for suppling DH to the residential area, excluding the sunk capital costs, is significantly lower than the heat cost for supplying heat with ground-source EHPs. The potential use of local ground-source heat linked to the exploitation level of residential area and energy performance of the buildings should be further analyzed in comparison to the use of other types of heat sources such as ambient air or ventilation air.

  • 273.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Costs of CO2 Emission Reduction in Biomass-Based District Heat Production Systems2014Inngår i: 22nd European Biomass Conference and Exhibition - EUBC&E2014, Hamburg, Germany, June 23-26, 2014, ETA-Florence Renewable Energies , 2014, s. 1401-1406Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Efficient biomass-based district heat production systems (DHS) can contribute to achieving the social targets of environmental and energy security for countries with demand for space and water heating. In this study, we evaluate the costs of CO2 emission reduction from biomass-based district heating systems in comparison with fossil-based ones under different scales of district heat production, and we relate this cost to estimated damage costs of CO2 emission. Our calculations are based on a real heat load duration curve for a city in southern Sweden. The value of cogenerated electricity is assumed to be equal to that produced in minimum-cost standalone condensing power plants. The difference of the production cost and CO2 emission between fossil- and biomass-based systems is used to calculate the cost of CO2 emission reduction. We consider four different sizes of DHSs, from 50 to 300 GWhheat per year, to investigate how the CO2 emission reduction costs varies with the scale of DHS. We found that the district heat production cost for a minimum-cost DHS depends on scales of district heating systems and that the cost effectiveness between biomass- and fossil-based systems varies for different scales. The costs of CO2 emission reduction vary from €7.7 to €9.4 per ton of CO2e depending on the size of DHS. This cost is generally lower than estimated damage costs of CO2 emission.

  • 274.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Effects of energy efficiency measures in district-heated buildings on energy systems2016Inngår i: Proceedings of International Conference on Sustainable Built Environment - SBE 16.  March 8 - 11, 2016, Hamburg, Germany, International Sustainable Built Environment , 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The primary energy savings depend on both the final energy savings and the energy efficiency of the supply system. In this study, we evaluate primary energy savings of different energy efficiency measures in a multistory district-heated building in Sweden. We consider various locations of the building with different district heat production systems (DHS) of different scales, technical charac-teristics and heat-load profiles. We show that the primary energy savings of the energy efficiency measures vary with the type of measure and with the type of energy supply systems. The energy efficiency measures give large final energy savings but their primary energy savings vary signifi-cantly. Of the energy efficiency measures, the measure that gives electricity savings but increase the use of district heat is the most primary energy efficient in relation to the final energy savings. Heat savings in buildings connected to small-scale DHS using heat-only boilers is more primary energy efficient than that in buildings connected to medium- and large- scale DHS using combined heat and power units. Evaluation of energy efficiency measures for district-heated buildings re-quires a systems perspective where the final energy savings in buildings are matched to the actu-al energy supply systems.

  • 275.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Integrated biomass-based production of district heat, electricity, motor fuels and pellets of different scales2013Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, s. 623-632Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Woody biomass can be used in different ways to contribute to sustainable development. In this paper, we analyze biomass-based production of district heat, electricity, pellets and motor fuels. We calculate production cost and biomass use of products from standalone production and from different district heat production options, including only heat production and various co/polygeneration options. We optimize the different district heat production systems considering the value of co/polygenerated products, other than district heat, as equal to those produced in minimum-cost standalone plants. Also, we investigate how the scale of district heating systems influences the minimum-cost composition of production units and district heat production costs. We find that co/polygenerated district heat is more cost and fuel efficient than that from heat-only production. Also, coproduction of electricity is more efficient than of motor fuels except for dimethyl-ether production in large district heat production systems. However, the cost difference is minor between coproduction of dimethyl-ether or electricity in such systems. Integrated biopellet production increases the production of electricity or motor fuel and reduces the production cost. District heat production cost depends on fuel price, however, its dependence is reduced if district heat production system is cost-minimized and based on co/polygenerated units. Also, the optimal composition and cost of district heat production depend on the scale of the system. The demand for biopellets may limit the potential integrated production of such a product. (C) 2012 Elsevier Ltd. All rights reserved.

  • 276.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Minimum-cost district heat production systems of different sizes under different environmental and social cost scenarios2014Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 136, s. 881-893Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    District heat systems can contribute to the achievement of social and environmental targets and energy security. District heat production systems (DHSs) vary in size depending on heat demand, which is influenced by several factors such as local climatic conditions and the sizes of the communities they serve. In this study, we analyzed options for minimum-cost DHSs of different sizes under different environmental and social cost scenarios. We calculated the production cost and primary energy use of district heat for minimum-cost options by considering a value of cogenerated electricity equivalent to the value of electricity produced in minimum-cost standalone condensing power plants. We varied the size of DHSs from 100 to 1800 GWhheat per year to investigate how size influences the minimum-cost compositions of production units and district heat production costs. We determined that the optimal composition and cost of district heat production is dependent on the size of the system, the overall load factor of heat demand and the technologies considered for both DHSs and reference power plants. In general, cogenerated district heat is more energy-efficient than district heat from heat-only production and also more cost-efficient, except for small DHSs, for which cogenerated district heat is more costly than heat-only production. The cost and primary energy use of district heat production is dependent on environmental and social cost scenarios; however, this dependence is reduced if a DHS is cost-minimized and based on cogenerated units.

  • 277.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Minimum-cost district heat production systems of different sizes under different taxation schemes2013Inngår i: International Conference on Applied Energy, July 1-4, 2013, Pretoria, 2013Konferansepaper (Fagfellevurdert)
  • 278.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för teknik, TEK.
    Gustavsson, Leif
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för teknik, TEK.
    Potentials of polygeneration in district heating systems2012Inngår i: World Renewable Energy Forum, WREF 2012, May 13-17, 2012; Denver, Colorado, 2012Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Operating capacity of district heat production depends on heat load demand which varies throughout the year. Large capital-extensive production capacity is used briefly for peak-load production while for off-peak periods only capital-intensive base-load is still used. For base-load production, cogeneration of district heat and electricity is often a primary-energy and cost efficient system. In this paper we analyse polygeneration of district heat, electricity and biomotor fuels. We show how different environmental taxation scenarios and changes in crude oil price influence the selection of district heat production units. Our analysis is based on an annual measured district-heat load. We calculate the production costs of district heat and total primary energy use for different polygeneration concepts. Costs are calculated under three environmental taxation scenarios and three crude oil price cases. First, we optimise the cost of a district heat production system based on cogeneration of electricity and heat. We consider cogenerated electricity as a byproduct with value as produced in a reference condensing power plant based on least cost options among different condensing power technologies. Next, we optimize and integrate different biomotor fuel production units into the district heating system considering biomotor fuels as byproducts which are fossil-motor fuel substitutes. We then relate the production cost of district heat and biomotor fuels to evaluate the elasticity between them. We show that the polygeneration improves the primary energy efficiency and reduce the production costs of the generated products. Also, environmental taxation and crude oil price have marginal influences to the produced district heat.

  • 279.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Production of district heat, electricity and/or biomotor fuels in renewable-based energy systems2020Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 202, artikkel-id 117672Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We analyze the possibilities to produce district heat, electricity and/or biomotor fuels in renewable-based energy systems considering district heating systems with annual heat demands between 110 and 1000 GWh. Several technical configurations to co/polygenerate district heat, electricity and/or biomotor fuels are cost optimized in the context of different standalone production options, woody biomass fuel prices and integrating costs of intermittent energy resources. The cost optimum configuration varies with the scale of the district heat production, as does the use of biomass to generate the same amount of product, and both depend on the context of the overall energy system. There are several state-of-the-art technologies that offer significant co/polygeneration benefits within district heating systems. An electric-based solution for transportation as well as an electric-based option for small-scale district heating systems are cost efficient and will reduce the use of biomass and help to integrate wind electricity into the overall energy system. For larger district heating systems, cogeneration of heat and electricity, and also in combination with electric heat pumps for a high biomass price, are cost efficient solutions. Further studies are needed, for example to understand how the deep energy renovation of buildings may influence the configuration of co-/polygeneration systems in district heating systems and potential savings of woody biomass.

  • 280.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Solar heating systems in renewable-based district heating systems2014Inngår i: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014 / [ed] Yan, J; Lee, DJ; Chou, SK; Desideri, U; Li, H, Elsevier, 2014, Vol. 61, nr 1460, s. 1460-1463Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study, we explored cost-optimal renewable-based district heat production systems and potential to integrate solar heating in such systems under different contexts. We investigated under which conditions a solar heating system become cost-efficient to integrate in district heat production systems and the consequences of this integration. We considered a small-scale district heat production system in the south of Sweden where district-heat production cost is higher and hence it is more cost efficient to integrate solar heating in such district heat production systems. The cost-efficiency of integrating solar heating in a minimum-cost renewable-based district heat production system depends on future fuel prices and investment costs of solar heating systems. In any case, integrating solar heating will help to reduce the use of other primary energy resources as biomass.

  • 281.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Heat supply of multi-apartment buildings with varied heat demands2014Inngår i: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014 / [ed] Yan, J; Lee, DJ; Chou, SK; Desideri, U; Li, H, Elsevier, 2014, Vol. 61, s. 1464-1467Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In multi-apartment buildings, changes in energy demand may influence cost-optimal heat supply options. District heat based on combined heat and power production has proved to be cost- and primary energy-efficient option for heating purposes in the residential sector. However, for customers with a low heat demand, local heat supply options may be more cost-efficient than district heat supply options. In this study, we investigated cost-optimal options to supply heat to a multi-apartment building in Växjö city, Sweden. We considered biomass-based alternatives for district heating and local heating based on wood pellet boiler and ground-source electric heat pump, also combined with solar heating systems. Furthermore, we evaluated how a varied yearly heat demand influences the cost and primary energy efficiency of the different heat technologies. We found that both fuel costs and initial investment costs of heating systems play an important role for the cost efficiency of the different heat supply options. District heat is not always cost efficient for multi-apartment buildings especially for low energy buildings with minimum heat demand. There is also a tradeoff between heating cost and primary energy use in supplying heat to multi-apartment buildings.

  • 282.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Tettey, Uniben Yao Ayikoe
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Implications of supplying district heat to a new urban residential area in Sweden2020Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 194, s. 1-18, artikkel-id 116876Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Here we analyze the cost, primary energy and CO2 implications of supplying district heat, considering different supply and return temperatures, to a new residential area in Växjö, Sweden. We explore four land exploitation alternatives consisting different types of buildings with various heated floor areas as well as occupancy densities and two levels of building energy efficiency, based on the Swedish building code and passive house criteria. The analysis shows that energy performance of the buildings and land exploitation alternatives strongly influence the annual heat demand and its profile, which steers the design of the local heat distribution network. Additionally, supply and return temperatures of district heat somewhat influence the design of the network. The distribution heat losses could be reduced by 25% and 50% if district heating systems of 65/30 °C and 50/20 °C, respectively, are used instead of a conventional 80/40 °C system. However, for the same land exploitation alternative, the local distribution heat losses are about the same whether or not the buildings are designed to meet the Swedish building code or passive house criteria, since the same pipe distance is required and the variation of pipe diameters is small. A 50/20 °C system increases electricity use to boost hot water temperature to avoid the risk of legionella bacteria, and this influences quantity of district heat supply, primary energy use and costs. Therefore, a 65/30 °C system appears to be more primary energy and cost efficient than a 50/20 °C system. Increased insulation of district heating network reduces heat losses but this is not cost effective due to increased investment cost. The results are similar whether or not the analysis is based on current energy supply or future renewable based energy supply. This study increases understanding of strategies for planning and designing new urban residential areas and their energy supply systems to reduce primary energy use as well as monetary costs, and to minimize the climate impacts of the built environment.

  • 283.
    Truong, Nguyen Le
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Sathre, Roger
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Primary energy and climate change effects of forest residues and fossil coal for electricity production with and without carbon capture and storage2016Inngår i: 24th European Biomass Conference and Exhibition. Hamburg, Germany, June 23-26, 2016, Amsterdam, The Netherlands, ETA-Florence Renewable Energies , 2016, s. 1394-1401Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Forest biomass that is currently unused, such as thinning and harvest residues, could be mobilized to produce bioelectricity, to mitigate climate change. An emerging technology for climate change mitigation is carbon capture and storage (CCS), which can reduce CO2 emissions from energy conversion facilities, but at a cost of additional fuel needed for process energy requirements. The use of forest residues that otherwise would decay on the forest floor, in an energy plant equipped with CCS, could result in a net reduction of CO2 emission to the atmosphere, while producing usable electricity. In this study, we analyse the climate change effects of using either coal or forest residues to produce electricity in large-scale conversion plants. We estimate the primary energy use, annual CO2 emission, annual change in CO2 concentration in the atmosphere and cumulative radiative forcing (CRF) of different energy systems that all produce the same quantity of electricity. We also consider the potential effects of future technology developments including gasification and integrated carbon capture processes. The results show that using forest residues to replace coal with current conversion technologies slightly increase the combustion CO2 emission, but in the long term give much lower net CO2 emission and mitigate climate change. The application of emerging gasification technology reduces primary energy use and CO2 emission compared to current technology, and hence increases the climate benefits. The use of CCS requires larger quantities of fuel, but could strongly reduce the CO2 emissions from conversion facilities, thus increasing the carbon benefits per unit of forest biomass used.

  • 284.
    Vadiee, Amir
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Dodoo, Ambrose
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Gustavsson, Leif
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    A Comparison Between Four Dynamic Energy Modeling Tools for Simulation of Space Heating Demand of Buildings.2019Inngår i: Cold Climate HVAC 2018. CCC 2018 / [ed] Johansson D., Bagge H., Wahlström Å., Springer, 2019, s. 701-711Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Different building energy modelling programs exist and are widely used to calculate energy balance of building in the context of energy renovation of existing buildings or in the design of energy performance of new buildings. The different tools have unique benefits and drawbacks for different conditions. In this study, four different types of building energy system modelling tools including TRNSYS, Energy Plus, IDA-Indoor Climate Energy (IDA-ICE) and VIP-Energy are used to calculate the energy balance of a recently built six-storey apartment building in Växjö, Sweden. The building is designed based on the current Swedish building code. The main outcomes of the software include hourly heating and cooling demands and indoor temperature profiles. We explore the general capabilities of the software and compare the results between them. For the studied building with similar input conditions such as weather climate data file, infiltration and ventilation ratio and internal heat gain, IDA-ICE modeled the highest space heating demand while the TRNSYS the lowest due to the simplification of thermal bridges. The main advance feature of VIP-Energy is the detail thermal bridge analysis while the main drawback is the complexity of using the model. EnergyPlus and TRNSYS can be used for energy supply system integration with the ability to add mathematical sub-modules to the models.

  • 285.
    Vanhoutteghem, Lies
    et al.
    Technical University of Denmark, Denmark.
    Tommerup, Henrik
    Technical University of Denmark, Denmark.
    Svendsen, Svend
    Danish Technical University, Denmark.
    Mahapatra, Krushna
    Mid Sweden University.
    Gustavsson, Leif
    Mid Sweden University.
    Haavik, Trond
    Segel As, Norway.
    Aabrekk, Synnøve
    Segel As, Norway.
    Paiho, Satu
    VTT, Finland.
    Ala-Juusela, Mia
    VTT, Finland.
    Sustainable renovation concepts for single-family houses, Deliverable D1.3 of the project Successful Sustainable Renovation Business for Single-Family Houses - SuccessFamilies.2009Rapport (Annet vitenskapelig)
    Abstract [en]

    Due to the introduction of low energy standards for new houses as minimum requirements, rising energy prices and generally more focus on energy performance, there is a need for farreaching energy efficiency improvements in connection with renovation if existing singlefamily houses in the Nordic countries are to have competitive power compared to new houses on the future housing market. If the market is able to explain this to the homeowners there is an open market with undreamt-of possibilities. Good technical solutions exist but need to be combined based on the full range of (standard) solutions in order to reach the low primary energy level of new houses. The typical single-family houses identified to have large primary energy saving potential almost descend from the same time period in each Nordic country. The first segment is houses built in large numbers in the 1960 and 1970 before tightening of the insulation standards in the building codes in the late 1970’s due to the oil crisis. The second segment is houses built before 1945 (except for Finland) where a large part of them has been renovated, but energy renovation of those houses today would still account for a large energy saving. The third segment is type houses from the post-war period in Finland. A complete energy efficient renovation of a typical house include post-insulation and sealing of the buildings envelope - roof/ceiling, façade, windows/doors and foundation and maybe slab on ground - installation of a mechanical ventilation system with high efficiency heat recovery and low electricity use and if not already there, an energy efficient heating system based on district heating, heat pump etc. This package of technical solutions can be carried out during an overall or step wise planned renovation dependent on the condition of the house, the financial possibilities of the homeowner etc. Calculation of packages of energy efficient renovation solutions targeted the three segments of houses show that primary energy use and heating bill can be reduced with up to about 75% or a factor 4 corresponding to the level of a new house or better. It seems that the passive house level can not quite be reached with standard solutions. They require that more ambitious measures are applied. The total investment needed to reduce the heating bill by a factor 4 including replacement of e.g. roof and windows is up to EUR 100,000. It is generally difficult to obtain an economy in balance in the sense that the annual payment on a cheap loan, e.g. mortgage refinancing, to finance the investment is not fully offset by the expected annual energy savings. Since, the cost of energy measures today may not correspond to the increased market value of the house, it is important to find mechanisms so that the total cost of the energy investments in the future is reflected as an increased value of the house. But with due regard to all the non-energy benefits, such as better and healthier indoor environment and comfort, and less dependence on expected future higher energy prices, energy efficient renovation will probably still be attractive for the average homeowner. One-stop-shops in the form of full-service providers of energy efficient renovation of singlefamily house are missing in the Nordic countries. This service is vital to open up the market. A one-stop-shop could be seen as a possibility to make it easy for the homeowner to comply with possible future requirements to realize far-reaching energy savings in connection with extensive renovations, provided that the building sector offers the solutions. Homeowners need someone to take care of all relevant steps necessary for the renovation of the house including quotation for the work, financing and management of the contract work. An ideal full-service concept in five phases is proposed, going from initial evaluation of the house, to extensive analyses, proposal for package solutions, coordinated execution and operation and finally management of the house after renovation.

  • 286.
    Vikman, Per-Åke
    et al.
    Mittuniversitetet, Institutionen för teknik, fysik och matematik.
    Gustavsson, Leif
    Mittuniversitetet, Institutionen för teknik, fysik och matematik.
    Klang, Anders
    Mittuniversitetet, Institutionen för teknik, fysik och matematik.
    Evaluating greenhouse gas balances and mitigation costs of bioenergy systems: a review of methodologies2004Rapport (Annet vitenskapelig)
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