| 1. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
-
Cost-optimized energy-efficient building envelope measures for a multi-storey residential building in a cold climate
- 2019
-
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€.
|
|
| 2. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
-
Effects of end-of-life management options for materials on primary energy and greenhouse gas balances of building systems
- 2019
-
Ingår i: Innovative Solutions for Energy Transitions. - : Elsevier. ; , s. 4246-4253
-
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.
|
|
| 3. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
-
Impacts of Common Simulation Assumptions in Sweden on Modelled Energy Balance of a Multi-family Building.
- 2019
-
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.
|
|
| 4. |
- Piccardo, Chiara, et al.
(författare)
-
Comparative Life-Cycle Analysis of Building Materials for the Thermal Upgrade of an Existing Building
- 2019
-
Ingår i: SBE19 Brussels - BAMB-CIRCPATH "Buildings as Material Banks - A Pathway For A Circular Future"5–7 February 2019, Brussels, Belgium. - : IOP Publishing.
-
Konferensbidrag (refereegranskat)abstract
- The existing building stock is estimated to need major renovations in the near future. At the same time, the EU energy-efficiency strategy entails upgrading the energy performance of renovated buildings to meet the nearly-zero energy standard. To upgrade existing buildings, two main groups of measures can be adopted: thermally-improved building envelope and energy-efficient technical devices. The first measure usually involves additional building materials for thermal insulation and new building cladding, as well as new windows and doors. A number of commercially-available materials can be used to renovate thermal building envelopes. This study compares the life-cycle primary energy use and CO2 emission when renovating an existing building using different materials, commonly used in renovated buildings. A Swedish building constructed in 1972 is used as a case-study building. The building's envelope is assumed to be renovated to meet the Swedish passive house standard. The entire life cycle of the building envelope renovation is taken into account. The results show that the selection of building materials can significantly reduce the production primary energy and associated CO2 emissions by up to 62% and 77%, respectively. The results suggest that a careful material choice can significantly contribute to reduce primary energy use and CO2 emissions associated with energy renovation of buildings, especially when renewable-based materials are used.
|
|
| 5. |
- Piccardo, Chiara, et al.
(författare)
-
Energy and carbon balance of materials used in a building envelope renovation
- 2019
-
Ingår i: SBE19 Brussels - BAMB-CIRCPATH "Buildings as Material Banks - A Pathway For A Circular Future"5–7 February 2019, Brussels, Belgium. - : IOP Publishing.
-
Konferensbidrag (refereegranskat)abstract
- Construction and demolition waste (CDW) are a priority waste stream in EU's polices, accounting for about 30% of all waste generated. At the same time, according to the EU energy-efficiency directive, existing buildings subject to significant renovation need to be upgraded in their thermal building envelope in order to meet higher energy performance standard. This involves additional building materials and hence increases the CDW generation. This study investigates the energy and CO2 emission balance of building envelope renovation when using different building materials, taking into account the production and end-of-life stages. The study is based on a Swedish case-study building assumed to be upgraded to the passive house standard. Benefits from waste recovering are considered, including construction and demolition wastes. The results show that the selection of building materials can significantly affect the primary energy and CO2 emission balances. Depending on the material alternative the end-of-life primary energy use and net CO2 emission can be reduced by 5%-21% and 2%-24%, respectively, compared to the initial primary energy use and net CO2 emission. Therefore, a careful material choice at the design stage, as well as an efficient waste management, can contribute to reduce primary energy use and CO2 emission associated with energy renovation of existing buildings.
|
|
| 6. |
- Tettey, Uniben Yao Ayikoe, 1979-, et al.
(författare)
-
Carbon balances for a low energy apartment building with different structural frame materials
- 2019
-
Ingår i: Innovative Solutions for Energy Transitions. - : Elsevier. ; , s. 4254-4261
-
Konferensbidrag (refereegranskat)abstract
- We analyse the life cycle carbon implications of a building, with structural frame of prefabricated concrete, prefabricated modular timber or cross laminated timber (CLT) elements, designed to meet the Swedish passive house criteria. The analysis covers non-biogenic carbon flows related to the building alternatives, over an assumed life time of 80 years. The building alternatives are all modelled to have the same housing service and operation energy demand. Substitution factors, showing the efficiency of CO2 emissions reductions when wood alternatives are used instead of non-wood alternatives, are calculated for the CLT and modular alternatives with reference to the concrete alternative. The results show that the CLT and modular buildings give less carbon emissions to the atmosphere during production and when the buildings are demolished at the end-of-life. Moreover, the wood residues from the production and end-of-life activities for the timber alternatives far exceed that for the concrete alternative. The substitution factors differ slightly between the CLT and the modular alternatives, and are significantly lower when fossil gas is substituted by wood residues instead of fossil coal. In summary, the life cycle carbon emissions are significantly lower for the timber alternatives.
|
|
| 7. |
- Tettey, Uniben Yao Ayikoe, 1979-, et al.
(författare)
-
Design strategies and measures to minimise operation energy use for passive houses under different climate scenarios
- 2019
-
Ingår i: Energy Efficiency. - : Springer. - 1570-646X .- 1570-6478. ; 12:1, s. 299-313
-
Tidskriftsartikel (refereegranskat)abstract
- Here, the implications of different design strategies and measures in minimising the heating and cooling demands of a multi-storey residential building, designed to the passive house criteria in Southern Sweden are analysed under different climate change scenarios. The analyses are conducted for recent (1996-2005) and future climate periods of 2050-2059 and 2090-2099 based on the Representative Concentration Pathway scenarios, downscaled to conditions in Southern Sweden. The considered design strategies and measures encompass efficient household equipment and technical installations, bypass of ventilation heat recovery unit, solar shading of windows, window size and properties, building orientation and mechanical cooling. Results show that space heating demand reduces, while cooling demand as well as risk of overheating increases under future climate scenarios. The most important design strategies and measures are efficient household equipment and technical installations, solar shading, bypass of ventilation heat recovery unit and window U-values and g-values. Total annual final energy demand decreased by 40-51%, and overheating is avoided or significantly reduced under the considered climate scenarios when all the strategies are implemented. Overall, the total annual primary energy use for operation decreased by 42-54%. This study emphasises the importance of considering different design strategies and measures in minimising the operation energy use and potential risks of overheating in low-energy residential buildings under future climates.
|
|
| 8. |
- Tettey, Uniben Yao Ayikoe, 1979-, et al.
(författare)
-
Effect of different frame materials on the primary energy use of a multi storey residential building in a life cycle perspective
- 2019
-
Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 185, s. 259-271
-
Tidskriftsartikel (refereegranskat)abstract
- Primary energy implications over the life cycle of a multi storey residential building with different building systems are explored here. The main structural materials of the buildings include precast concrete, cross laminated timber (CLT) and prefabricated timber modules (modular). The analysis covers energy and material flows from different life cycle phases of the building versions, designed to meet the energy performance of the Swedish building code (BBR) and passive house criteria. The CLT and modular buildings were found to result in lower production primary energy use and higher biomass residues compared to the concrete alternative. The heating value of the recoverable biomass residues from the production phase of the CLT building is significantly larger than the primary energy required for its production. Primary energy use for production and construction constitutes 20-30% and 36-47% of the total primary energy use for production, construction, space heating, ventilation and demolition for the BBR and passive buildings, respectively. Space heating with combined heat and power (CHP) and ventilation electricity for the BBR and passive building versions form 70-79% and 52-63%, respectively, of the total primary energy use for production, construction, space heating, ventilation and demolition for a lifespan of 80 years. The CLT and modular buildings give 20-37% and 9-17% lower total life cycle primary energy use, respectively, than the concrete alternative when space heating is from CHP. (C) 2019 Elsevier B.V. All rights reserved.
|
|
| 9. |
- Tettey, Uniben Yao Ayikoe, 1979-, et al.
(författare)
-
Primary energy and CO2 emissions implications of different insulation, cladding and frame materials for residential buildings
- 2019
-
Ingår i: SBE 19 - Emerging Concepts for Sustainable Built Environment 22–24 May 2019, Helsinki, Finland. - : Institute of Physics (IOP). ; , s. 1-11
-
Konferensbidrag (refereegranskat)abstract
- In this study, we analyse and compare the primary energy use and carbon dioxide (CO2) emissions associated with different insulation, cladding and frame materials for a constructed concrete frame multi-storey residential building in Sweden. Our approach consists of identifying individual materials giving the lowest primary energy use and CO2 emissions for each building envelope part and based on that, modelling different material combinations to achieve improved alternatives of the concrete frame building with the same operation energy use based on the Swedish building code or passive house criteria. We analyse the complete materials and energy chains, including material losses as well as conversion and fuel cycle losses. The analysis covers the primary energy use to extract, process, transport, and assemble the materials and the resulting CO2 emissions to the atmosphere. The results show wide variations in primary energy and CO2 emissions depending on the choice of building envelope materials. The materials for external walls contribute most to the primary energy and CO2 emissions, followed by foundation, roof and external cladding materials. The improved building alternatives with wood construction frames, wood external cladding, expanded polystyrene as foundation insulation and cellulose insulation in the external walls and roof result in about 36 - 40% lower production primary energy use and 42 - 49% lower CO2 emissions than the improved concrete alternative when achieving the same thermal performance. This study suggests that strategies for low-energy buildings should be combined with resource-efficient and low carbon materials in the production phase to mitigate climate change and achieve a sustainable built environment. © 2019 IOP Publishing Ltd. All rights reserved.
|
|
| 10. |
- Tettey, Uniben Yao Ayikoe, 1979-, et al.
(författare)
-
Primary energy implications for low-energy buildings with different frame construction systems under varying climate scenarios
- 2019
-
Ingår i: eceee 2019 Summer Study on energy efficiency. - : European Council for an Energy Efficient Economy (ECEEE). - 9789198387841 - 9789198387858 ; , s. 1407-1417
-
Konferensbidrag (refereegranskat)abstract
- In this study, a 6 storey prefabricated concrete building in Sweden is used as reference to explore life cycle primary energy implications of different frame construction systems under various climate scenarios. The building was redesigned as a low-energy building to the Swedish passive house criteria with frame construction systems in cross laminated timber, prefabricated timber modules and concrete. Using a system perspective approach, we account for relevant energy and material flows linked to the production, construction, operation and end-of-life phases of the building alternatives, including thermal mass effects under recent (2013) as reference and future (2090-2099) climate periods based on representative concentration pathways (RCP) 2.6, 4.5 and 8.5 scenarios. Results show that the buildings' heating and cooling demands vary significantly under the climate scenarios. The timber systems give lower production primary energy and higher biomass residues than the concrete alternative. The concrete system requires slightly lower operation energy due to thermal mass benefits but still, the timber systems give overall lower life cycle primary energy balance. This study shows that low-energy timber buildings with efficient energy supply can play an important role in mitigating climate change for a resource-efficient and sustainable built environment under current and future climate scenarios. © 2019 European Council for an Energy Efficient Economy. All rights reserved.
|
|
