| 1. |
- 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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| 2. |
- 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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| 3. |
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| 4. |
- 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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| 5. |
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| 6. |
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| 7. |
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| 8. |
- 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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| 9. |
- 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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| 10. |
- 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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| 11. |
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| 12. |
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| 13. |
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| 14. |
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| 15. |
- 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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| 16. |
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| 17. |
- Dodoo, Ambrose
(författare)
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Life cycle primary energy use and carbon emission of residential buildings
- 2011
-
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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| 18. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
-
Life cycle primary energy use and carbon footprint of wood-frame conventional and passive houses with biomass-based energy supply
- 2013
-
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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| 19. |
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| 20. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Lifecycle carbon implications of conventional and low-energy multi-storey timber building systems
- 2014
-
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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| 21. |
- 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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| 22. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Lifecycle primary energy analysis of low-energy timber building systems for multi-story residential buildings
- 2014
-
Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 81, s. 84-97
-
Tidskriftsartikel (refereegranskat)abstract
- A system-wide lifecycle approach is used here to explore the primary energy implications of three timber building systems for a multi-storey building designed to a high energy-efficiency level. The three building systems are: cross laminated timber, beam -and-column, and modular prefabricated systems. The analysis considers the energy and material flows in the production, use and post-use lifecycle stages of the buildings. The effects of insulation material options and the contribution of different building elements to the production energy for the buildings are explored. The results show that external and internal walls account for the biggest share of the production energy for all building systems and its contribution is comparable for the different systems. In contrast, there is significant variation in the production primary energy for the roof-ceilings and intermediate floor-ceilings for the different building systems. Overall, the cross laminated timber building system gives the lowest lifecycle primary energy balance, as this building is insulated with stone wool and has better airtightness in contrast to the other building systems which are insulated with glass wool and have lower airtightness performance. With improved airtightness and insulation substitution, the total primary energy use for the beam-and-column and modular building systems can be reduced by 7% and 9%, respectively.
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| 23. |
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| 24. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Primary energy and carbon dioxide implications of low-energy renovation of a Swedish apartment building
- 2013
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Ingår i: Passivhus Norden 2013. ; , s. 270-282
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Konferensbidrag (refereegranskat)abstract
- Measures to improve energy efficiency in existing buildings offer a significant opportunity to reduce primary energy use and carbon dioxide (CO2) emissions. The construction of new low energy buildings is important in the long term, but has small effect on the building sector’s overall energy use in the short term, as the rate of addition of new buildings to the building stock is low. In this study we analyse the potential for reducing primary energy use and CO2 emissions in an existing Swedish apartment building with energy efficiency renovation measures. We model changes to a case-study building with an annual final heat energy demand of 94 kWh/m2 to achieve a low-energy building. The modelled changes include improved water taps, windows and doors, increased insulation in attic and exterior walls, electric efficient appliances and installation of a plate heat exchanger in the ventilation system. We analyse the life cycle primary energy and CO2 implications of improving the buildings to a low-energy building. We consider different energy supply systems, including scenarios where the end-use heating technology is resistance heating, electric heat pump or district heating. We find that greater lifecycle primary energy and CO2 reduction are achieved when an electric resistance heated building is renovated than when a district heated building is renovated. Material production primary energy use and CO2 emission become relatively more significant when the operation energy is reduced. However, the increases in material production impacts are strongly offset by greater primary energy and CO2 reductions from the operation phase of the building, resulting in significant lifecycle benefits. Additional roof insulation gives the biggest primary energy efficiency when the building is heated with resistance heating. For electric heat pump or district heating, more electric efficient appliances give the biggest primary energy efficiency. Still the heat supply choice has greater impact on primary energy use and CO2 emissions.
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| 25. |
- Dodoo, Ambrose, 1979-
(författare)
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Primary energy impact of ventilation heat recovery in a timber-frame building with different heat systems.
- 2012
-
Ingår i: Forum Holzbau Nordic, Växjö 12.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Here, we analyze the impact of ventilation heat recovery (VHR) on the operationprimary energy use of a case-study timber-frame building using different heatsupply systems including electric resistance heating, bedrock heat pump and districtheating based on combined heat and power (CHP) production. We model theprimary energy use for the original and improved level of energy efficiency of thebuilding, both with and without VHR. VHR increases the electrical energy used forventilation and reduces the heat energy used for space heating. Significant primaryenergy savings is achieved when VHR is used in electric resistance heatedbuildings than in district heated buildings. For district heated buildings the primaryenergy savings are small. VHR systems can give substantial final energy reduction,but the primary energy benefit depends strongly on the type of heatsupply system, and also on the amount of electricity used for VHR and the airtightnessof buildings. This study shows the importance of considering the interactionsbetween heat supply systems and VHR systems to reduce primary energyuse in buildings.
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| 26. |
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| 27. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Primary energy implications of ventilation heat recovery in residential buildings
- 2011
-
Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 43:7, s. 1566-1572
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we analyze the impact of ventilation heat recovery (VHR) on the operation primary energy use in residential buildings. We calculate the operation primary energy use of a case-study apartment building built to conventional and passive house standard, both with and without VHR, and using different end-use heating systems including electric resistance heating, bedrock heat pump and district heating based on combined heat and power (CHP) production. VHR increases the electrical energy used for ventilation and reduces the heat energy used for space heating. Significantly greater primary energy savings is achieved when VHR is used in resistance heated buildings than in district heated buildings. For district heated buildings the primary energy savings are small. VHR systems can give substantial final energy reduction, but the primary energy benefit depends strongly on the type of heat supply system, and also on the amount of electricity used for VHR and the airtightness of buildings. This study shows the importance of considering the interactions between heat supply systems and VHR systems to reduce primary energy use in buildings.
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| 28. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Recycling of lumber
- 2014. - 1
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Ingår i: Handbook of recycling. - Waltham, MA : Elsevier. - 9780123964595 ; , s. 151-163
-
Bokkapitel (refereegranskat)abstract
- Wood from sustainably managed forests can play important roles both as material and as fuel in a transition to a low-carbon society. Wood is widely used as an energy source and as a physical and structural material in diverse applications, including furniture and joinery, pulp and paper, and construction material. There is large potential to improve resource efficiency and thereby reduce greenhouse gas (GHG) emissions through efficient management of post-use wood materials. This chapter explores post-use management of wood products from resource efficiency and climate perspectives. Primary energy and GHG balances are important metrics to understand the resource efficiency of climate change mitigation strategies involving post-use wood products. Primary energy use largely determines natural resource efficiency and steers the environmental impacts of material recovery and production. This chapter describes the mechanisms through which post-use management of recovered wood materials can affect primary energy use and GHG impacts of wood products. To further understand the implications of different post-use management options for wood products, we then explore several quantitative case-studies.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
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| 33. |
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| 34. |
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| 35. |
- Gustavsson, Leif, et al.
(författare)
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Primary energy implications of end-use energy efficiency measures in district heated buildings
- 2011
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Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 43:1, s. 38-48
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Tidskriftsartikel (refereegranskat)abstract
- In this study we explore the effects of end-use energy efficiency measures on different district heat production systems with combined heat and power (CHP) plants for base load production and heat-only boilers for peak and medium load productions. We model four minimum cost district heat production systems based on four environmental taxation scenarios, plus a reference district heat system used in Östersund, Sweden. We analyze the primary energy use and the cost of district heat production for each system. We then analyze the primary energy implications of end-use energy efficiency measures applied to a case-study apartment building, taking into account the reduced district heat demand, reduced cogenerated electricity and increased electricity use due to ventilation heat recovery. We find that district heat production cost in optimally-designed production systems is not sensitive to environmental taxation. The primary energy savings of end-use energy efficiency measures depend on the characteristics of the district heat production system and the type of end-use energy efficiency measures. Energy efficiency measures that reduce more of peak load than base load production give higher primary energy savings, because the primary energy efficiency is higher for CHP plants than for boilers. This study shows the importance of analyzing both the demand and supply sides as well as their interaction in order to minimize the primary energy use of district heated buildings.
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| 36. |
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| 37. |
- Mahapatra, Krushna, 1974-, et al.
(författare)
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System analysis of and stakeholders’ perceptions on end-use energy efficiency measures for existing Swedish multi-family buildings
- 2012
-
Ingår i: COBEE 12, International Conference on Building Energy and Environment. Boulder, Colorado, USA, August 1-4.
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Konferensbidrag (refereegranskat)abstract
- In Sweden, there is opportunity to implement energy efficiency measures in about one million existing apartments that are likely to be refurbished within the next 20 years. System analyses of installation of energy efficient windows, and increased insulation in attic and in exterior walls for an existing multi-story building showed that the primary energy savings for the measures depend on the energy supply system. Energy efficiency potential was higher with installation of efficient windows than improved attic insulation. Responses of 673 chairpersons of co-operative hosing associations to a mail-in survey in 2010 also showed that greater proportion of respondents perceived that energy efficient windows had advantages over insulation improvements. However, majority had no intention to implement such measures during next 10 years and economic factors guide their decisions. Lack of expertise to assess the benefits of energy efficiency measures was the most cited hindrances to energy efficiency investments.
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| 38. |
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| 39. |
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| 40. |
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| 41. |
- Tettey, Uniben Yao Ayikoe, et al.
(författare)
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Effects of different insulation materials on primary energy and CO2 emission of a multi-storey residential building
- 2014
-
Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 82, s. 369-377
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 42. |
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| 43. |
- Tettey, Uniben Yao Ayikoe, et al.
(författare)
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Primary energy implications of different wall insulation materials for buildings in a cold climate
- 2014
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Ingår i: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014. - : Elsevier. ; , s. 1204-1207
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 44. |
- Truong, Nguyen Le, 1976-, et al.
(författare)
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Effects of energy-efficiency measures and climate change mitigation policy instruments on primary energy use in district-heated buildings
- 2013
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Ingår i: ECEEE Summer Study proceedings. - : European Council for an Energy Efficient Economy (ECEEE). - 9789198048223 ; , s. 515-522
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 45. |
- Truong, Nguyen Le, 1976-, et al.
(författare)
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Effects of heat and electricity saving measures in district-heated multistory residential buildings
- 2014
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 118, s. 57-67
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 46. |
- Truong, Nguyen Le, 1976-, et al.
(författare)
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Heat supply of multi-apartment buildings with varied heat demands
- 2014
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Ingår i: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014. - : Elsevier. ; , s. 1464-1467
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Konferensbidrag (refereegranskat)abstract
- 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.
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