| 1. |
- Ahn, Namhyuck, et al.
(författare)
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Circular economy in mass timber construction : State-of-the-art, gaps and pressing research needs
- 2022
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Ingår i: Journal of Building Engineering. - : Elsevier. - 2352-7102. ; 53
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Tidskriftsartikel (refereegranskat)abstract
- The building and construction sector is a major contributor to human environmental impact on the planet. It follows that the sector's contribution is also crucial for transition towards a low carbon society and circular economy (CE). Mass timber products, are one of the sustainable alternatives to traditional building materials and have led to the recent revolution in timber construction. While environmental benefits of mas timber manufacturing and construction is well documented the end-of-life (EOL) and the post-EOL options for mass timber buildings, their environmental benefits and CE potential are discussed much less. Short history of construction technology involving prefabricated mass timber panels compared to traditional building types results in virtually no documented cases of panelized mass timber structures reaching the EOL stage and no practical examples of incorporating CE concepts in such projects. In this study, a two-step systematic literature review was used, to define and classify 23 CE-based governing principles from six categories in the construction industry, and to use those principles to analyze the state-of-the-art circular approach in mass timber research. The study covered a total of 90 papers, of which 68 focused on the general construction industry and 22 specifically on the mass timber construction. Results of this review suggest substantial gaps in knowledge and pressing research needs for the development of holistic approaches to prepare the mass timber construction for circular economy.
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| 2. |
- Ahn, Namhyuck, et al.
(författare)
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Envisioning mass timber buildings for circularity : life cycle assessment of a mass timber building with different end-of-life (EoL) and post-EoL options
- 2023
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Ingår i: WCTE 2023-World Conference on Timber Engineering. - : Curran Associates, Inc.. - 9781713873297 ; , s. 3581-3587
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Konferensbidrag (refereegranskat)abstract
- The foundation of the circular economy in the construction sector is based on implementing the deconstruction and reuse of buildings, providing the potential for a closed loop of building materials within the supply chain. Mass timber buildings using large, prefabricated elements and certain types of reversible mechanical connections are deemed to have great potential for post end-of-life (EoL) options, including recycling and reuse. To fully characterize the benefits of reusing post-use mass timber in new construction projects, it is crucial to conceptualize a ‘grave-to-gate’ approach, including the complete analysis of post-EoL activities and impacts on the material’s second life. In this study, a comparative life cycle assessment (LCA) including different EoL and post-EoL options for a virtual reference mid-rise mass timber building in the Pacific Northwest (PNW) of the United States was conducted. Among four different deconstruction and reuse scenarios examined in this study, a case of nearly complete reconstruction of a mass timber building for the second service life used as an idealized reference established an optimistic limit for reduction of global warming potential (GWP) by 13-41% compared to the ‘demolish and landfill’ decision, depending on the scenario. The demolition and landfill scenario had the lowest net impact since the GWMP calculations accounted for the carbon storage benefits in the landfill in addition to the carbon stored in the building.
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| 3. |
- Al-Najjar, Ahmad, et al.
(författare)
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Modular multi-storey construction with cross-laminated timber : Life cycle environmental implications
- 2023
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Ingår i: Wood Material Science & Engineering. - : Informa UK Limited. - 1748-0272 .- 1748-0280. ; 18:2, s. 525-539
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the life cycle environmental implications of modular multi-storey building with cross-laminated timber (CLT) volumetric elements are analysed, considering the product, construction, service life, end-of-life and post-use stages. A bottom-up attributional approach is used to analyse the environmental flows linked to the global warming potential (GWP), acidification potential (AP) and eutrophication potential (EP) impacts of the building for a 50-year reference study period. The result shows that the building’s life cycle impacts can vary considerably, depending on the energy production profile for the operation of the building. The product, construction and end-of-life stages constitute a significant share of the life cycle impacts, and the importance of these stages increase as the energy production profile evolves towards a low-carbon energy mix. For the GWP, the product and construction stages constitute 13% of the total life cycle impact when the operational energy is based on a coal-based marginal electricity. The contribution of this stage increases to 81% when electricity is based on a plausible long-term Swedish average mix. The patterns of the life cycle EP and AP impacts are also closely linked to the energy production profile for the assessment. The analysis shows that a 5% reduction in the GWP impact in the product stage is achievable with emerging solutions for the improved structural design of CLT buildings. This study highlights the need for strategies to improve the life cycle environmental profile of modular CLT buildings.
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| 4. |
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| 5. |
- Bonakdar, Farshid, 1977-, et al.
(författare)
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Cost-optimum analysis of building fabric renovation in a Swedish multi-story residential building
- 2014
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Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 84, s. 662-673
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we analysed the cost-optimum level of building fabric elements renovation in a multi-story residential building. We calculated final energy use for space heating of the building considering a wide range of energy efficiency measures, for exterior walls, basement walls, attic floor and windows. Different extra insulation thicknesses for considered opaque elements and different U-values for new windows were used as energy efficiency measures. We calculated difference between the marginal saving of energy cost for space heating and the investment cost of implemented energy efficiency measures, in order to find the cost-optimum measure for each element. The implications of building lifespans, annual energy price increase and discount rate on the optimum measure were also analysed. The results of the analysis indicate that the contribution of energy efficiency measures to the final energy use reduces, significantly, by increasing the thickness of extra insulation and by reducing the U-value of new windows. We considered three scenarios of business as usual (BAU), intermediate and sustainability, considering different discount rates and energy price increase. The results of this analysis suggest that the sustainability scenario may offer, approximately, 100% increase in the optimum thickness of extra insulation compare to BAU scenario. However, the implication of different lifespans of 40, 50 or 60 years, on the optimum measure appears to be either negligible or very small, depending on the chosen scenario. We also calculated the corresponding U-value of the optimum measures in order to compare them with the current Swedish building code requirements and passive house criteria. The results indicate that all optimum measures meet the Swedish building code. None of the optimum measures, however, meet the passive house criteria in BAU scenario. This study suggests that the employed method of building renovation cost-optimum analyses can be also applied on new building construction to find the cost-optimum design from energy conservation point of view.
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| 6. |
- Bonakdar, Farshid, et al.
(författare)
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Implications of energy efficiency renovation measures for a Swedish residential building on cost, primary energy use and carbon dioxide emission
- 2013
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Ingår i: ECEEE Summer Study proceedings. - : European Council for an Energy Efficient Economy (ECEEE). - 9789198048223 ; , s. 1287-1296
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Konferensbidrag (refereegranskat)abstract
- Building sector accounts for 40% of total primary energy use in the EU. Measures to improve energy efficiency in existing buildings may reduce primary energy use and carbon dioxide (CO2) emission. In this study, we analysed the potential final energy savings for space heating and cost-effectiveness of different energy efficiency measures for a Swedish multi-story residential building from building owner perspective. The implications of the measures on primary energy use and CO2 emission were also explored. Building envelope elements were considered as energy efficiency measures. Required investment for energy efficiency measures per saved energy price was used as indication for the cost-effectiveness of energy renovation. We analysed three scenarios of energy renovation where the building is in its initial state, once with and then without renovation need for repair and maintenance purpose and the scenario for the current state of building. The current state of the building has some modification compared to the initial state. We performed sensitivity analysis to study the influence of economic parameters on the cost-effectiveness of energy efficiency measures. The results showed that the energy savings and cost-effectiveness of the measures depend on building characteristics, energy efficiency measures and the assumed economic parameters. Modelling of final energy use, before and after energy renovation, and its cost analysis showed that the considered energy efficiency measures were not economically profitable with the initial economic assumption (6% discount rate and 1.9% annual energy price increase during 50-year lifespan). For the renovation package of all energy efficiency measures, energy renovation appeared to be profitable when discount rate and annual energy price increase were 3% and 2.5% (or larger), respectively. Primary energy use and CO2 emission were reduced by 45 to 50% for the same package for the building with cogeneration-based district heating.
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| 7. |
- Boussaa, Youcef, 1993-, et al.
(författare)
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Analysis of cost-effective energy efficiency measures for thermal envelope of a multi-apartment building in Sweden
- 2020
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Ingår i: Proceedings of 12th International Conference on Applied Energy, Part 3, Sweden, 2020. - : ICAE. - 9789198673821
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Konferensbidrag (refereegranskat)abstract
- A large potential for energy savings can be found in building envelopes of the existing Swedish dwelling stock. This study analyzes the final energy savings and cost implications of energy efficiency measures for an existing multi-apartment building in Sweden. Energy efficiency improvements consisting of high-performance windows as well as doors, and additional insulation to attic floor and exterior walls were modelled to the building’s thermal envelope. Dynamic energy balance simulations were performed to determine the final energy savings of the improvements. The cost-effectiveness of the improvements were then analyzed considering the net present value of the energy cost savings and the investment costs of the improvement measures. The results showed that additional insulation to the attic floor is the only cost-effective measure for the building under the existing operating conditions. The other improvement measures give high final energy savings but are not cost effective due to their high investment costs.
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| 8. |
- Boussaa, Youcef, 1993-, et al.
(författare)
-
Comprehensive renovation of a multi-apartment building in Sweden : techno-economic analysis with respect to different economic scenarios
- 2023
-
Ingår i: Building Research & Information. - : Taylor & Francis Group. - 0961-3218 .- 1466-4321.
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Tidskriftsartikel (refereegranskat)abstract
- A wider deployment of nearly zero energy buildings (NZEBs) is expected to contribute to the transition to a decarbonized and energy-efficient building sector in Europe. This study proposed an integrated energy-economic analysis to exemplify the feasibility of NZEB renovation in temperate climate. A parametric analysis was performed to identify technical building system configurations that give minimum share of renewable energy systems contributing to NZEB level. Final energy savings, global costs and cost-effectiveness of renovating a building to NZEB level are analysed, considering active and passive energy efficiency measures (EEMs). The active EEMs included efficient water taps and heat recovery ventilation, and the passive EEMs encompassed insulations to roof, exterior walls and ground floor, and improvements of windows and doors. The building had initial final energy use of 133 kWh/m2 year for space heating, domestic hot water production (DHW) and facility electricity. The results show that NZEB level is achieved with active and passive EEMs, without renewable energy systems for scenarios with low discount rates and high future energy price escalations. The annual final energy use for space heating, DHW and facility electricity is reduced cost-effectively by 37-54%. Furthermore, increasing size of PV-system enhanced cost-effectiveness by lowering total global costs.
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| 9. |
- Boussaa, Youcef, 1993-, et al.
(författare)
-
Energy efficient measures for thermal envelope of a multi-apartment building in Sweden : Analysis of cost effectiveness with respect to carbon abatement costs implementation
- 2021
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Ingår i: eceee 2021 Summer Study on energy efficiency: a new reality?. - : European Council for an Energy Efficient Economy (ECEEE). - 9789198387889 ; , s. 1015-1024
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Konferensbidrag (refereegranskat)abstract
- A considerable share of the existing buildings in Europe has low energy performance and are expected to last at least for the next 50 years. The operation of these buildings causes high atmospheric greenhouse gases emissions, besides low thermal comfort for occupants. In Sweden, most of the existing buildings are residential, consisting of multi- and single-family houses. Large final energy savings can be achieved by integrating energy efficient measures (EEMs) to the thermal envelopes of these buildings. However, it is often a challenge to achieve a considerable energy savings and realize cost effectiveness simultaneously. This study investigates the effect of carbon taxes implementation on the cost effectiveness of EEMs applied to an existing multi-apartment building in southern Sweden. It explores the implications of different additional insulation thicknesses for exterior walls and roof, and high-performance windows and doors, for the final energy use and carbon dioxide (CO2) emissions of the building. The final energy savings of the EEMs are estimated through dynamic energy balance simulations and the CO2 emissions are calculated considering the full energy chains. The cost effectiveness of the EEMs are analyzed with and without carbon abatement costs considering the investment costs and associated net present value of costs savings of the EEMs. The results show that replacing the existing windows give the highest final energy savings, reducing the building’s space heating demand by 23 %. The cost optimal analysis without carbon abatement costs shows that all the analyzed thicknesses of roof insulation and high-performance windows are cost effective. Considering the carbon abatement costs altered the cost effectiveness of the EEMs, with exterior walls as well as ground floor insulations and door replacement becoming cost effective for certain thicknesses and U-values, respectively.
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| 10. |
- Boussaa, Youcef, 1993-, et al.
(författare)
-
Integrating Passive Energy Efficient Measures to the Building Envelope of a Multi-Apartment Building in Sweden : Analysis of Final Energy Savings and Cost Effectiveness
- 2023
-
Ingår i: Buildings. - : MDPI. - 2075-5309. ; 13:10
-
Tidskriftsartikel (refereegranskat)abstract
- A major challenge in building energy renovation is to cost effectively achieve notable energy savings. This paper investigates cost-effective passive energy-efficiency measures for thermal envelope retrofit of a typical Swedish multi-apartment building from the 1970s. Here, the use of different types of insulation materials for the retrofits of roof, exterior walls, and ground floor are analyzed along with changing windows and doors with varying thermal transmittance values. The cost-effectiveness analysis is based on the net present value of the investment costs of the energy-efficiently measures and the achieved energy cost saving. Different economic scenarios and renovation cases are considered in techno-economic analyses to determine the cost-effective energy-efficiency retrofit measures. The results indicate that improved windows reduce energy demand for space heating by up to 23% and yield the highest final energy savings. However, additional mineral wool roof insulation is the most cost-effective measure under all economic scenarios. This measure gave the lowest ratio of cost effectiveness of about 0.1, which was obtained under the stable scenario. The final energy savings that can be achieved in a cost-effective manner vary between 28% and 61%, depending on the economic scenario and renovation case. This analysis emphasizes the influence of different renovation cases and economic parameters on the cost effectiveness of passive energy-efficiency measures.
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| 11. |
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| 12. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Building energy-efficiency standards in a life cycle primary energy perspective
- 2011
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 43:7, s. 1589-1597
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Tidskriftsartikel (refereegranskat)abstract
- In this study we analyze the life cycle primary energy use of a wood-frame apartment building designed to meet the current Swedish building code, the Swedish building code of 1994 or the passive house standard, and heated with district heat or electric resistance heating. The analysis includes the primary energy use during the production, operation and end-of-life phases. We find that an electric heated building built to the current building code has greater life cycle primary energy use relative to a district heated building, although the standard for electric heating is more stringent. Also, the primary energy use for an electric heated building constructed to meet the passive house standard is substantially higher than for a district heated building built to the Swedish building code of 1994. The primary energy for material production constitutes 5% of the primary energy for production and space heating and ventilation of an electric heated building built to meet the 1994 code. The share of production energy increases as the energy-efficiency standard of the building improves and when efficient energy supply is used, and reaches 30% for a district heated passive house. This study shows the significance of a life cycle primary energy perspective and the choice of heating system in reducing energy use in the built environment.
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| 13. |
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| 14. |
- Dodoo, Ambrose, et al.
(författare)
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Carbon implications of end-of-life management of building materials
- 2009
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Ingår i: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 53:5, s. 276-286
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Tidskriftsartikel (refereegranskat)abstract
- In this study we investigate the effects of post-use material management on the life cycle carbon balance of buildings, and compare the carbon balance of a concrete-frame building to that of a wood-frame building. The demolished concrete is either landfilled, or is crushed into aggregate followed by exposure to air for periods ranging from 4 months to 30 years to increase carbonation uptake of CO2. The demolished wood is assumed to be used for energy to replace fossil fuels. We calculate the carbon flows associated with fossil fuel used for material production, calcination emission from cement manufacture, carbonation of concrete during and after its service life, substitution of fossil fuels by recovered wood residues, recycling of steel, and fossil fuel used for post-use material management. We find that carbonation of crushed concrete results in significant uptake of CO2. However, the CO2 emission from fossil fuel used to crush the concrete significantly reduces the carbon benefits obtained from the increased carbonation due to crushing. Stockpiling crushed concrete for a longer time will increase the carbonation uptake, but may not be practical due to space constraints. Overall, the effect of carbonation of post-use concrete is small. The post-use energy recovery of wood and the recycling of reinforcing steel both give higher carbon benefit than the post-use carbonation. We conclude that carbonation of concrete in the post-use phase does not affect the validity of earlier studies reporting that wood-frame buildings have substantially lower carbon emission than concrete-frame buildings.
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| 15. |
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| 16. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Climate change impacts on overheating risk and primary energy use for space conditioning of a Swedish multi-story building
- 2016
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Ingår i: CLIMA 2016.
-
Konferensbidrag (refereegranskat)abstract
- In this study we investigate the potential impacts of future climate change scenarios on overheating risk and primary energy use for space conditioning of a newly built multi-story apartment building in Växjö, Sweden. The building is district heated and potentially cooled by stand-alone air conditioners. We consider climate change scenarios for the period 2050-2059, historical climate of 1961-1990 and recent climate of 1996-2005. The climate change scenarios are based on the representative concentration pathways 4.5 and 8.5. We explore the risk of overheating of the building and analyse the impacts of different strategies for overheating control, including increased airing and solar shading besides mechanical cooling. We investigate the implications of different renewable based electricity supply options for space cooling and ventilation of the building. The results show that the space heating demand is significantly reduced and cooling demand is strongly increased for the building with the future climate scenarios. Furthermore the risk of overheating increases under the climate change scenarios. Among the overheating control strategies analysed, solar shading is the single most effective measure, giving the lowest primary energy use for space conditioning. Complementing the electricity from biomass-fired condensing power plants with solar-based electricity reduced the space conditioning primary energy use by 4-9%. Adding increased airing to the control strategies increased the primary energy use.
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| 17. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Climate impacts of wood vs. non-wood buildings
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report documents the findings of a project commissioned by the SwedishAssociation of Local Authorities and Regions on energy and climateimplications of building structural-frame materials from a life cycle perspective.The report is compiled by researchers within the Sustainable Built EnvironmentGroup (SBER) at Linnaeus University, Växjö, Sweden, and it addresses theterms of reference of the project agreement, including review of existingliterature and reports on energy and climate implications of wood-frame andnon-wood-frame building systems.The report’s primarily focus is: the effect of material choice on different lifecycle stages of a building; the significance of building frame material in relationto the total primary energy use and climate impact of a building; keymethodological issues linked to life cycle analysis of buildings; and theimportance of system perspective in analysis of a building’s climate impacts.
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| 18. |
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| 19. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Cost-optimized energy-efficient building envelope measures for a multi-storey residential building in a cold climate
- 2019
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Ingår i: Innovative Solutions for Energy Transitions. - : Elsevier. ; , s. 3760-3767
-
Konferensbidrag (refereegranskat)abstract
- In this study we analyse cost-optimal building envelope measures including insulation for attic roof, ground floor and exterior walls, and efficient windows and doors for new buildings. The analysis is based on a multi-storey building in south of Sweden with an expected lifetime of at least 100 years. We integrate dynamic energy simulation, total and marginal economic analysis, and consider different scenarios of real discount rates and annual energy price increases. Our analysis shows that cost-optimal thicknesses of insulations for the building envelope elements are significantly higher than those required to meet the current Swedish building code’s minimum energy requirements. For windows, the cost-optimal U-value is about the same as required to fulfil the minimum requirement of the Swedish building code. Overall, large energy and cost savings are achieved when the cost-optimal measures are cumulatively implemented. Compared to the reference, annual space heating reduction of 28-43% is achieved for the building with the cost-optimal measures under the analysed period of 50 years. The cost savings varied between 21 and 188 k€.
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| 20. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Economic analyses of energy efficiency renovation measures and packages for a district heated multi-family residential building
- 2016
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Ingår i: 11th Conference on Sustainable Development of Energy, Water and Environment Systems. - : Faculty of Mechanical Engineering and Naval Architecture, Zagreb. ; , s. 321-321
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Konferensbidrag (refereegranskat)abstract
- Improved energy efficiency in buildings is a major part of the overall strategy to reduce fossil fuels use and thereby mitigate climate change. In this study, we present and demonstrate an approach for economic analysis of building energy efficiency measures, and investigate the profitability of energy efficiency renovation measures for a Swedish multi-family building. The energy renovation measures include additional insulation to basement, exterior walls, and roof and improved windows. They are analysed when applied either singly or in packages. We find that the cost-effectiveness of the building envelope retrofit measures is very sensitive to the economic-related parameters applied including, real discount rates and energy price increase over time. Cost optimal final energy savings for the energy renovation package varies between 29% and 38%, depending on the choice of real discount rate and energy price increase. This study shows the significance of different building envelope measures and economic-related parameters in achieving large energy savings from building envelope renovation cost-efficiently.
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| 21. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Effect of energy efficiency requirements for residential buildings in Sweden on lifecycle primary energy use
- 2014
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Ingår i: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014. - : Elsevier. ; , s. 1183-1186
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Konferensbidrag (refereegranskat)abstract
- In this study we analyze the lifecycle primary energy use of a wood-frame apartment building designed to meet the current Swedish building code or passive house criteria, and heated with district heat or bedrock heat pump. We employ a lifecycle perspective methodology and determine the production, operation and end-of-life primary energy use of the buildings. We find that the passive house requirement strongly reduces the final energy use for heating compared to the current Swedish building code. However, the primary energy use is largely determined by the energy supply system, which is generally outside the mandate of the building standards. Overall, buildings with district heating have lower life-cycle primary energy use than alternatives heated with heat pump. The primary energy for production is small relative to that for operation, but it is more significant as the energy-efficiency standard of building improves and when efficient energy supply is used. Our results show the importance of a system-wide lifecycle perspective in reducing primary energy use in the built environment. A life cycle primary energy perspective is needed to minimize overall primary energy use, and future building energy-efficiency standards may reflect the full energy use during a building's life cycle. This could include primary energy implications for production, operation and end-of-life of buildings.
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| 22. |
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| 23. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Effect of thermal mass on life cycle primary energy balances of a concrete- and a wood-frame building
- 2012
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 92:1, s. 462-472
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Tidskriftsartikel (refereegranskat)abstract
- In this study we analyze the effect of thermal mass on space heating energy use and life cycle primary energy balances of a concrete- and a wood-frame building. The analysis includes primary energy use during the production, operation and end-of-life phases. Based on hourby- hour dynamic modeling of heat flows in building mass configurations we calculate the energy saving benefits of thermal mass during the operation phase of the buildings. Our results indicate that the energy savings due to thermal mass is small and varies with the climatic location and energy efficiency levels of the buildings. A concrete-frame building has slightly lower space heating demand than a wood-frame alternative, due to the benefit of thermal mass inherent in concrete-based materials. Still, a wood-frame building has a lower life cycle primary energy balance than a concrete-frame alternative. This is due primarily to the lower production primary energy use and greater bioenergy recovery benefits of the wood-frame buildings. These advantages outweigh the energy saving benefits of thermal mass. We conclude that the influence of thermal mass on space heating energy use for buildings located in Nordic climate is small and that wood-frame buildings with CHP-based district heating would be an effective means of reducing primary energy use in the built environment.
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| 24. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Effects of Climate Change for Thermal Comfort and Energy Performance of Residential Buildings in a Sub-Saharan African Climate
- 2019
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Ingår i: Buildings. - : MDPI. - 2075-5309. ; 9:10
-
Tidskriftsartikel (refereegranskat)abstract
- This study presents an analysis of the impacts of climate change on thermal comfort and energy performance of residential buildings in Ghana, in sub-Saharan Africa, and explores mitigation as well as adaptation strategies to improve buildings' performance under climate change conditions. The performances of the buildings are analyzed for both recent and projected future climates for the Greater Accra and Ashanti regions of Ghana, using the IDA-ICE dynamic simulation software, with climate data from the Meteonorm global climate database. The results suggest that climate change will significantly influence energy performance and indoor comfort conditions of buildings in Ghana. However, effective building design strategies could significantly improve buildings' energy and indoor climate performances under both current and future climate conditions. The simulations show that the cooling energy demand of the analyzed building in the Greater Accra region is 113.9 kWh/m(2) for the recent climate, and this increases by 31% and 50% for the projected climates for 2030 and 2050, respectively. For the analyzed building in the Ashanti region, the cooling energy demand is 104.4 kWh/m(2) for the recent climate, and this increases by 6% and 15% for the 2030 and 2050 climates, respectively. Furthermore, indoor climate and comfort deteriorate under the climate change conditions, in contrast to the recent conditions.
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| 25. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Effects of end-of-life management options for materials on primary energy and greenhouse gas balances of building systems
- 2019
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Ingår i: Innovative Solutions for Energy Transitions. - : Elsevier. ; , s. 4246-4253
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Konferensbidrag (refereegranskat)abstract
- In this study we have analysed the life cycle primary energy and greenhouse gas (GHG) balances of concrete-frame and timber-frame multi-storey building alternatives, designed to meet the current Swedish building code, considering different end-of-life scenarios. The scenarios include recycling of concrete and steel, cascading by recycling of wood into particle board and energy recovery at the end-of-life of the board, energy recovery of wood by combustion, and landfilling of wood with and without landfill gas (LFG) recovery. The energy recovered is assumed to replace fossil coal or gas. Our analysis accounts for energy and GHG flows in the production and end-of-life phases. We estimate the GHG emission changes achieved per unit of difference in finished wood in buildings or in harvest forest biomass between the timber buildings and the concrete building. The results show that the timber building systems give significantly lower life cycle primary energy balances than the concrete building system for all the end-of-life options. The concrete building system gives higher life cycle GHG balances than the timber alternatives for all the end-of-life options, except when wood is landfill without LFG recovery. The end-of-life primary energy and GHG benefit of wood materials is most significant for energy recovery while the benefit of cascading is low. However, replacing fossil gas instead of fossil coal significantly reduce the carbon benefits of the timber alternatives. The benefits of recycling steel and concrete are small. This study shows that end-of-life options for building materials can offer opportunities to reduce energy use and GHG emissions in the built environment.
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| 26. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Effects of future climate change scenarios on overheating risk and primary energy use for Swedish residential buildings
- 2014
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Ingår i: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014. - : Elsevier. ; , s. 1179-1182
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Konferensbidrag (refereegranskat)abstract
- In this study we use dynamic computer simulation modelling to investigate the potential impact of future climate change scenarios on the risk of overheating and annual primary energy requirements for space heating and cooling of residential buildings in Växjö, Sweden. The buildings are designed to the energy efficiency level of conventional or passive house, and are assumed to be heated with district heating and cooled with mechanical cooling system. We compare different climate change scenarios to a baseline which represents the climate data of Växjö for 1996-2005. The climate change scenarios are based on projected temperature changes under the representative concentration pathways (RCP) 4.5 and 8.5 scenarios. The result shows that the risk of overheating increases under the climate change scenarios. Furthermore space heating demand is reduced and cooling demand is increased for the analyzed buildings, and the changes are proportionally more significant for the passive compared to the conventional building.
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| 27. |
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| 28. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Energy and economic implications of buildings and construction
- 2021
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Ingår i: The Construction Industry. - : Nova Science Publishers, Inc.. - 9781685073381 - 9781685074210 ; , s. 215-247
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Bokkapitel (refereegranskat)abstract
- The building and construction sectors account for a large share ofthe global total primary energy use, which is currently dominated byfossil and non-renewable fuels. The sectors are expected to play a majorrole in the transition to a sustainable society with low-energy intensity.Energy is used during the life cycle of buildings for materialsmanufacture, transport, construction, operation, maintenance anddemolition. A wide range of resources, from forest-based materials suchas timber and bamboo to ore-based materials such as steel and concreteare used for building and construction projects. Energy is used forvarious building operation activities, including for space heating and cooling, tap water heating, and lighting and appliances. Materials andenergy resources use are associated with significant environmentalimpacts including atmospheric, solid and waterborne emissions. Thereis growing emphasis on strategies to reduce energy use and therebymitigate climate change. This chapter looks at the energy and economicimplications of buildings and construction products, adopting a lifecycle perspective. It examines the implications of different constructionmaterials, design strategies and thermal envelope improvementmeasures for energy, climate and economic performances of buildings.The implications of building renovation and post-use building materialsmanagement strategies are discussed. Case studies and analyses fromdifferent regions and climates are explored to demonstrate theimplications of different choices and decisions.
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| 29. |
- Dodoo, Ambrose, 1979-
(författare)
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Energy and indoor thermal comfort performance of a Swedish residential building under future climate change conditions
- 2020
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Ingår i: 12th Nordic Symposium on Building Physics (NSB 2020), Tallinn. E3S Web Conference. - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- he latest climate change projections for Sweden suggest mean annual temperature increase of up to 5.5 degrees C by 2100, compared to 1961-1990 levels. In this study we investigate the potential impacts of climate change on the energy demand for space conditioning, overheating risk and indoor thermal comfort of a modern multi-storey residential building in Sweden. We explore climate change adaptation strategies to improve the building's performance under the climate change conditions, including increased ventilation, solar shading, improved windows and mechanical cooling. The building is analysed under future climate projections for the 2050-2059 time frame, with representative concentration pathway (RCP) 2.6, 4.5 and 8.5 scenarios. The building's performances under these future climates are compared to those under the historical climate of 1961-1990 and recent climate of 1981-2010. The results suggest that climate change will significantly influence energy performance and indoor comfort conditions of buildings in the Swedish context. Overheating hours and Predicted Percentage of Dissatisfied (PPD) increased significantly under the future climate scenarios. Furthermore space heating demand is reduced and cooling demand is increased for the studied building. However, effective adaptation strategies significantly improved the buildings' energy and indoor climate performances under both current and future climate conditions.Keywords
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| 30. |
- Dodoo, Ambrose, et al.
(författare)
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Energy implications of end-of-life options for building materials
- 2008
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Ingår i: First International Conference on Building Energy and Environment, Proceedings Vols 1-3. - Dalian, China : Dalian University Technology Press. - 9780981688169 ; , s. 2025-2032
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Konferensbidrag (refereegranskat)abstract
- The energy flows associated with the materials comprising a building can be a significant part of the total energy used in a building's life cycle. Buildings have finite life spans, and the materials from demolished buildings can be either a burden that must be disposed, or a resource that can be used. In this paper we analyse the end-of-life energy impacts of concrete, steel and wood. End-of-life options considered include reuse; recycling; downcycling; energy recovery; and disposal in landfill. We follow the life cycles of the building materials from the acquisition of natural resources through to the end of the product's life cycle. We identify possibilities and constraints for integrating more effective end-of-life material processing options into existing industrial systems.
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| 31. |
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| 32. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Energy use and overheating risk of Swedish multi-storey residential buildings under different climate scenarios
- 2016
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 97, s. 534-548
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the extent to which different climate scenarios influence overheating risk, energy use and peak loads for space conditioning of district heated multi-storey buildings in Sweden are explored. Furthermore, the effectiveness of different overheating control measures and the implications of different electricity supply options for space cooling and ventilation are investigated. The analysis is based on buildings with different architectural and energy efficiency configurations including a prefab concrete-frame, a massive timber-frame and a light timber-frame building. Thermal performance of the buildings under low and high Representative Concentration Pathway climate scenarios for 2050–2059 and 2090–2099 are analysed and compared to that under historical climate of 1961–1990 and recent climate of 1996–2005. The study is based on a bottom-up methodology and includes detailed hour-by-hour energy balance and systems analyses. The results show significant changes in the buildings’ thermal performance under the future climate scenarios, relative to the historical and recent climates. Heating demand decreased significantly while cooling demand and overheating risk increased considerably with the future climate scenarios, for all buildings. In contrast to the cooling demand, the relative changes in heating demand of the buildings under the future climate scenarios are somewhat similar. The changes in the space conditioning demands and overheating risk vary for the buildings. Overheating risk was found to be slightly higher for the massive-frame building and slightly lower for the light-frame building.
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| 33. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Exploring the synergy between structural engineering design solutions and life cycle carbon footprint of cross-laminated timber in multi-storey buildings
- 2022
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Ingår i: Wood Material Science & Engineering. - : Taylor & Francis Group. - 1748-0272 .- 1748-0280. ; 17:1, s. 30-42
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Tidskriftsartikel (refereegranskat)abstract
- Low-carbon buildings and construction products can play a key role in creating a low-carbon society. Cross-laminated timber (CLT) is proposed as a prime example of innovative building products, revolutionising the use of timber in multi-storey construction. Therefore, an understanding of the synergy between structural engineering design solutions and climate impact of CLT is essential. In this study, the carbon footprint of a CLT multi-storey building is analysed in a life cycle perspective and strategies to optimise this are explored through a synergy approach, which integrates knowledge from optimised CLT utilisation, connections in CLT assemblies, risk management in building service-life and life cycle analysis. The study is based on emerging results in a multi-disciplinary research project to improve the competitiveness of CLT-based building systems through optimised structural engineering design and reduced climate impact. The impacts associated with material production, construction, service-life and end-of-life stages are analysed using a process-based life cycle analysis approach. The consequences of CLT panels and connection configurations are explored in the production and construction stages, the implications of plausible replacement scenarios are analysed during the service-life stage, and in the end-of-life stage the impacts of connection configuration for post-use material recovery and carbon footprint are analysed. The analyses show that a reduction of up to 43% in the life cycle carbon footprint can be achieved when employing the synergy approach. This study demonstrates the significance of the synergy between structural engineering design solutions and carbon footprint in CLT buildings.
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| 34. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Final energy savings and cost-effectiveness of deep energy renovation of a multi-storey residential building
- 2017
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Ingår i: Energy. - : Pergamon Press. - 0360-5442 .- 1873-6785. ; 135, s. 563-576
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Tidskriftsartikel (refereegranskat)abstract
- In this study we present a method for analysis of cost-effectiveness of end-use energy efficiency measures and demonstrate its application for modelling a wide range of energy renovation measures for a typical 1970s multi-family building in Sweden. The method integrates energy balance and bottom-up economic calculations considering total and marginal investment costs of energy efficiency measures as well as net present value of total and marginal savings of the measures. The energy renovation measures explored include additional insulation to basement walls, exterior walls, and attic floor, improved new windows, efficient electric appliances and lighting, efficient water taps, glazed enclosed balcony systems, and exhaust air ventilation heat recovery systems. The measures are analysed first individually and then designed to form economic packages. Our results show that improved windows give the biggest single final energy savings while resource-efficient taps is the most cost-effective measure for the building. We find that the cost-effectiveness of the energy renovation measures is sensitive to real discount rates and energy price increases. Cost-optimal final heat savings varies between 34% and 51%, depending on the choice of real discount rate and energy price increase. The corresponding electricity savings varies between 35% and 43%. This study shows a method and the significance of various technical and economic-related parameters in achieving deep energy savings cost-efficiently.
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| 35. |
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| 36. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Impacts of Common Simulation Assumptions in Sweden on Modelled Energy Balance of a Multi-family Building.
- 2019
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Ingår i: Cold Climate HVAC 2018. - Cham : Springer. - 9783030006617 - 9783030006624 ; , s. 689-699
-
Konferensbidrag (refereegranskat)abstract
- Here, we explore key input parameters and common assumptions for energy balance analysis of residential buildings in Sweden and assess their impacts on simulated energy demand of a building. Our analysis is based on dynamic hour-by-hour energy balance modelling of a typical Swedish multi-storey residential building constructed in 1972. The simulation input parameters studied are related to microclimate, building envelope, occupancy behaviour, ventilation, electric and persons heat gains. The results show that assumed indoor temperature set points, internal heat gains and efficiency of ventilation heat recovery systems have significant impact on the simulated energy demand. For microclimate parameters, the outdoor temperature, ground solar reflection and window shading gave significant variations in the simulated space heating and cooling demands. We found that input parameter values and assumptions used for building energy simulation vary significantly in the Swedish context, giving considerably different estimated annual final energy demands for the analysed building. Overall, the estimated annual final space heating demand of the building varied between 50 and 125 kWh/m2 depending on the simulation dataset used. This study suggests that site-specific parameter values may be appropriate for accurate analysis of a building’s energy performance to reduce data input uncertainties, as such factors may have a significant impact on building energy balance and energy savings of retrofit measures.
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| 37. |
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| 38. |
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| 39. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Influence of simulation assumptions and input parameters on energy balance calculations of residential buildings
- 2017
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 120:1, s. 718-730
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we modelled the influence of different simulation assumptions on energy balances of two variants of a residential building, comprising the building in its existing state and with energy-efficient improvements. We explored how selected parameter combinations and variations affect the energy balances of the building configurations. The selected parameters encompass outdoor microclimate, building thermal envelope and household electrical equipment including technical installations. Our modelling takes into account hourly as well as seasonal profiles of different internal heat gains. The results suggest that the impact of parameter interactions on calculated space heating of buildings is somewhat small and relatively more noticeable for an energy-efficient building in contrast to a conventional building. We find that the influence of parameters combinations is more apparent as more individual parameters are varied. The simulations show that a building's calculated space heating demand is significantly influenced by how heat gains from electrical equipment are modelled. For the analyzed building versions, calculated final energy for space heating differs by 9-14 kWh/m(2) depending on the assumed energy efficiency level for electrical equipment. The influence of electrical equipment on calculated final space heating is proportionally more significant for an energy-efficient building compared to a conventional building. This study shows the influence of different simulation assumptions and parameter combinations when varied simultaneously. (C) 2016 Elsevier Ltd. All rights reserved.
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| 40. |
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| 41. |
- Dodoo, Ambrose, et al.
(författare)
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Life cycle primary energy implication of retrofitting a wood-framed apartment building to passive house standard
- 2010
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Ingår i: Resources, Conservation and Recycling. - : Elsevier. - 0921-3449 .- 1879-0658. ; 54:12, s. 1152-1160
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Tidskriftsartikel (refereegranskat)abstract
- Here we analyze the life cycle primary energy implication of retrofitting a four-storey wood-frame apartment building to the energy use of a passive house. The initial building has an annual final energy use of 110 kWh/m(2) for space and tap water heating. We model improved thermal envelope insulation, ventilation heat recovery, and efficient hot water taps. We follow the building life cycle to analyze the primary energy reduction achieved by the retrofitting, considering different energy supply systems. Significantly greater life cycle primary energy reduction is achieved when an electric resistance heated building is retrofitted than when a district heated building is retrofitted. The primary energy use for material production increases when the operating energy is reduced but this increase is more than offset by greater primary energy reduction during the operation phase of the building, resulting in significant life cycle primary energy savings. Still, the type of heat supply system has greater impact on primary energy use than the final heat reduction measures.
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| 42. |
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| 43. |
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| 44. |
- Dodoo, Ambrose
(författare)
-
Life cycle primary energy use and carbon emission of residential buildings
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, the primary energy use and carbon emissions of residential buildings are studied using a system analysis methodology with a life cycle perspective. The analysis includes production, operation, retrofitting and end-of-life phases and encompasses the entire natural resource chain. The analysis focuses, in particular, on to the choice of building frame material; the energy savings potential of building thermal mass; the choice of energy supply systems and their interactions with different energy-efficiency measures, including ventilation heat recovery systems; and the effectiveness of current energy-efficiency standards to reduce energy use in buildings. The results show that a wood-frame building has a lower primary energy balance than a concrete-frame alternative. This result is primarily due to the lower production primary energy use and greater bioenergy recovery benefits of wood-frame buildings. Hour-by-hour dynamic modeling of building mass configuration shows that the energy savings due to the benefit of thermal mass are minimal within the Nordic climate but varies with climatic location and the energy efficiency of the building. A concrete-frame building has slightly lower space heating demand than a wood-frame alternative, because of the benefit of thermal mass. However, the production and end-of-life advantages of using wood framing materials outweigh the energy saving benefits of thermal mass with concrete framing materials.A system-wide analysis of the implications of different building energy-efficiency standards indicates that improved standards greatly reduce final energy use for heating. Nevertheless, a passive house standard building with electric heating may not perform better than a conventional building with district heating, from a primary energy perspective. Wood-frame passive house buildings with energy-efficient heat supply systems reduce life cycle primary energy use.An important complementary strategy to reduce primary energy use in the building sector is energy efficiency improvement of existing buildings, as the rate of addition of new buildings to the building stock is low. Different energy efficiency retrofit measures for buildings are studied, focusing on the energy demand and supply sides, as well as their interactions. The results show that significantly greater life cycle primary energy reduction is achieved when an electric resistance heated building is retrofitted than when a district heated building is retrofitted. For district heated buildings, the primary energy savings of energy efficiency measures depend on the characteristics of the heat production system and the type of energy efficiency measures. Ventilation heat recovery (VHR) systems provide low primary energy savings where district heating is based largely on combined heat and power (CHP) production. VHR systems can produce substantial final energy reduction, but the primary energy benefit largely depends on the type of heat supply system, the amount of electricity used for VHR and the airtightness of buildings.Wood-framed buildings have substantially lower life cycle carbon emissions than concrete-framed buildings, even if the carbon benefit of post-use concrete management is included. The carbon sequestered by crushed concrete leads to a significant decrease in CO2 emission. However, CO2 emissions from fossil fuels used to crush the concrete significantly reduce the carbon benefits obtained from the increased carbonation due to crushing. Overall, the effect of carbonation of post-use concrete is small. The post-use energy recovery of wood and the recycling of reinforcing steel both provide higher carbon benefits than post-use carbonation.In summary, wood buildings with CHP-based district heating are an effective means of reducing primary energy use and carbon emission in the built environment.
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| 45. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Life cycle primary energy use and carbon footprint of wood-frame conventional and passive houses with biomass-based energy supply
- 2013
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 112, s. 834-842
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Tidskriftsartikel (refereegranskat)abstract
- In this study the primary energy use and carbon footprint over the life cycle of a wood-frame apartmentbuilding designed either conventionally or to the passive house standard are analyzed. Scenarioswhere the building is heated with electric resistance heaters, bedrock heat pump or cogeneration-baseddistrict heat, all with biomass-based energy supply, are compared. The analysis covers all life cyclephases of the buildings, including extraction of raw materials, processing of raw materials into buildingmaterials, fabrication and assembly of materials into a ready building, operation and use of the buildings,and the demolition of the buildings and the post-use management of the building materials. Theprimary energy analysis encompasses the entire energy chains from the extraction of natural resourcesto the delivered energy services. The carbon footprint accounting includes fossil fuel emissions, cementprocess reaction emissions, potential avoided fossil fuel emissions due to biomass residues substitutionand end-of-life benefit of post-use materials. The results show that the operation of the buildingaccounts for the largest share of life cycle primary energy use. The passive house design reduces theprimary energy use and CO2 emission for heating, and the significance of this reduction depends onthe type of heating and energy supply systems. The choice of end-use heating system strongly influencesthe life cycle impacts. A biomass-based system with cogeneration of district heat and electricitygives low primary energy use and low carbon footprint, even with a conventional design. The amountof biomass residues from the wood products chain is large and can be used to substitute fossil fuels.This significantly reduces the net carbon footprint for both the conventional and passive house designs.This study shows the importance of adopting a life cycle perspective involving production, construction,operation, end-of-life, and energy supply when evaluating the primary energy use and climaticimpacts of both passive and conventional buildings.
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| 46. |
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| 47. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Life cycle primary energy use of nearly-zero energy building and low-energy building
- 2017
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Ingår i: ECEEE 2017 Summer Study. - : European Council for an Energy Efficient Economy (ECEEE). ; , s. 1075-1081
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Konferensbidrag (refereegranskat)abstract
- Energy legislations are increasingly driving towards buildings with very low operation final energy use as part of efforts to reduce energy use and climate impact of the built environment. In this study we analyse the life cycle primary energy use of a recently constructed Swedish conventional 6-storey apartment building and compare it to variants designed as nearly-zero energy building or as low-energy building with a combination of improved thermal envelope and passive design strategies. We maintain the architectural design of the constructed building and improve the thermal properties of the envelope to achieve a low-energy building and also nearly-zero energy building including solar thermal collectors. We consider scenarios where the building variants are heated with renewable energy using cogenerated district heating, also complemented with solar heating system. We follow the life cycle of the building versions and analyse their total primary energy use, considering the production, operation and end-of-life phases. The results show that the relative significance of the production phase increases as buildings are made to achieve very low operational energy use. The production phase accounts for 17 % of the total primary energy use for production, operation and demolition of the constructed building for a 50-year lifespan. The corresponding values for the nearly-zero energy and low-energy building variants ranges between 30 to 31 %. Overall, the life cycle primary energy use for the nearly-zero energy and low-energy building variants are about 30–35 % lower compared to the constructed building.
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| 48. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Lifecycle carbon implications of conventional and low-energy multi-storey timber building systems
- 2014
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Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 82, s. 194-210
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Tidskriftsartikel (refereegranskat)abstract
- A consequential-based lifecycle approach is used here to explore the carbon implications of conventional and low-energy versions of three timber multi-storey building systems. The building systems are made of massive wood using cross laminated timber (CLT) elements; beam-and-column using glulam and laminated veneer lumber (LVL) elements; and prefabricated modules using light-frame volume elements. The analysis encompasses the entire resource chains during the lifecycle of the buildings, and tracks the flows of carbon from fossil energy, industrial process reactions, changes in carbon stocks in materials, and potential avoided fossil emissions from substitution of fossil energy by woody residues. The results show that the low-energy version of the CLT building gives the lowest lifecycle carbon emission while the conventional version of the beam-and-column building gives the highest lifecycle emission. Compared to the conventional designs, the low-energy designs reduce the total carbon emissions (excluding from tap water heating and household and facility electricity) by 9%, 8% and 9% for the CLT, beam-and-column and modular systems, respectively, for a 50-year lifespan located in Växjö. The relative significance of the construction materials to the fossil carbon emission varies for the different energy-efficiency levels of the buildings, with insulation dominating for the low-energy houses and plasterboard dominating for the conventional houses.
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| 49. |
- Dodoo, Ambrose, 1979-
(författare)
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Lifecycle impacts of structural frame materials for multi-storey building systems
- 2019
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Ingår i: Journal of Sustainable Architecture and Civil Engineering. - : Kauno Technologijos Universitetas. - 2029-9990 .- 2335-2000. ; 24:1, s. 17-28
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Tidskriftsartikel (refereegranskat)abstract
- In this study the lifecycle primary energy and greenhouse gas (GHG) implications of multi-storey building versions with different structural frame materials as well as construction systems are analysed considering flows from the production, operation and end-of-life phases and the full natural resources chains. The analysed building versions include conventional and modern construction systems with light-frame timber, reinforced concrete-frame, massive timber frame, beam-and-column timber frame or modular timber frame structural systems and are designed to the energy efficiency level of the passive house criteria. The results show that the lifecycle primary energy use and GHG emissions for the reinforced concrete building system are higher than those for the timber-based building systems, due primarily to the lower production primary energy use and GHG emissions as well as greater amount of biomass residues when using wood-based materials. The operation primary energy use and GHG emission for the buildings are lower when heated with cogenerated district heating compared to when heated with electric-based heat pump, showing the significance of heat supply choice. The findings emphasize the importance of structural frame material choice and system-wide lifecycle perspective in reducing primary energy use and GHG emissions in the built environment.
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| 50. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Lifecycle primary energy analysis of conventional and passive houses
- 2012
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Ingår i: International Journal of Sustainable Building Technology and Urban Development. - 2093-761X .- 2093-7628. ; 3:2, s. 105-111
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Tidskriftsartikel (refereegranskat)abstract
- In this study we analyse the primary energy implications of thermal envelope designs and construction systems, for a 4-storey apartment building, including the full lifecycle phases and the entire energy chains. We maintain the architectural design of the reference building, and alter the thermal properties of the envelope components and include heat recovery of ventilation air to achieve buildings with thermal properties similar to three existing passive houses in Sweden. We also vary the building frame material from the reference wood case to reinforced concrete, and vary the heat supply system between district heating and electric resistance heating. We follow the lifecycle of the buildings and analyse and compare their lifecycle primary energy use, considering the production, operation and end-of-life energy uses. The results show that the lifecycle primary energy use of a passive house building is substantially lower when it is heated with district heating instead of electricity. A passive house with district heating uses 42–45% less lifecycle primary energy than the same house with electric heating. Lifecycle primary energy use is 2–4% less when a passive house is constructed with a wood frame instead of a concrete frame. This study shows that material choice becomes increasingly important as buildings are made to the passive house standard and as efficient heat supply systems are used.
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