| 1. |
- Ahmed, Samar, et al.
(författare)
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Analysis of future carbon-neutral energy system : The case of Växjö Municipality, Sweden
- 2022
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Ingår i: Smart Energy. - : Elsevier. - 2666-9552. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- In line with the Swedish target of carbon neutrality by 2045, the municipality of Växjö in Kronoberg County has set its own target to be carbon neutral in 2030. Currently, the Municipality's partially decentralized energy system relies heavily on interconnected electricity supply from the national grid, and fuels imports from other parts of Sweden. Under this circumstance, several concerns arise, including: in which ways future demand changes induce supply changes, and whether a future carbon-neutral energy system will be less costly in a sustained-electricity supply condition. In this study, techno-economic evaluations are conducted for different carbon-neutral scenarios for Växjö’s future energy system in 2030 and 2050, using an hour-by-hour dynamic energy simulation tool of EnergyPLAN. Projections for the future energy demands for Växjö were developed and modeled, based on the development strategies and on the national sustainable future scenarios in Sweden. Results for the Växjö’s carbon-neutral scenarios showed that the current energy system is sufficient to satisfy future heat demand. However, fulfilling demands of electricity for all sectors and fuels for transport and industry is a challenge. In the short term and at increased energy demand and price, being carbon neutral is technically viable without major changes in energy supply technologies. However, in the long term, investment for intermittent renewable energy resources, together with carbon capture and storage is considered to be viable financially. Therefore, planning for a carbon-neutral Växjö based on local investments showed to be a feasible strategy.
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| 2. |
- 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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| 3. |
- Boussaa, Youcef, 1993-, et al.
(författare)
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Comprehensive renovation of a multi-apartment building in Sweden : techno-economic analysis with respect to different economic scenarios
- 2023
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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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| 4. |
- Boussaa, Youcef, 1993-, et al.
(författare)
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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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| 5. |
- Boussaa, Youcef, 1993-, et al.
(författare)
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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
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Ingår i: Buildings. - : MDPI. - 2075-5309. ; 13:10
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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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| 6. |
- 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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| 7. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Primary energy benefits of cost-effective energy renovation of a district heated multi-family building under different energy supply systems
- 2018
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 143, s. 69-90
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Tidskriftsartikel (refereegranskat)abstract
- The European Union's Directive on energy performance of buildings emphasizes the need to take cost-effectiveness into account when measures are implemented for improved building energy efficiency. In this study, we investigate cost-effective energy renovation measures for a district heated building under different contexts, including varied locations, energy supply systems and economic scenarios. We determine the final and primary energy savings of cost-effective energy renovation packages for the building in the different contexts. The measures analysed include: improved insulation for attic floor, basement walls, and exterior walls; improved windows and doors; resource-efficient taps; heat recovery of exhaust ventilation air; energy-efficient household appliances and lighting. We consider three existing Swedish energy supply systems of varying district heat production scale and tariffs, and also plausible renewable-based energy supply systems. Our analysis calculates the final energy savings of the measures including the cost-effective renovation packages on hourly basis and links these to the different energy supply systems. The cost-effectiveness analysis is based on a double-stage optimization method, considering total and marginal investment costs of renovation measures as well as associated net present values of total and marginal cost savings. The results show that significant final and primary energy savings can be achieved when energy renovation measures are implemented for the building in the different contexts. This study shows that heat demand in existing Swedish building could be about halved while electricity use may be reduced considerably with cost-effective energy renovation measures. The economic viability of the renovation measures is sensitive to the economic regimes especially discount rates and energy price increase.
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| 8. |
- Dodoo, Ambrose, 1979-, et al.
(författare)
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Techno-economic performance of heat recovery air handling units for residential buildings in a sub-arctic climate
- 2020
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Ingår i: The 12<sup>th</sup> International Conference on Applied Energy – ICAE2020, December 1-10, 2020, Bangkok/Virtual. - : ICAE.
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Konferensbidrag (refereegranskat)abstract
- This study analysed the final and primary energy savings as well as cost-effectiveness of centralised and semi-centralised heat recovery air handling units (AHUs) configurations for existing and efficient variants of a district heated multi-dwelling building. The AHUs have counter-flow plate or rotary heat exchangers, and their performances for the building variants are analysed considering different economic scenarios and frost conditions. Very few studies have explored the techno-economic implications of such AHU configurations in the context of building retrofitting. The final energy savings is calculated on hourly basis using dynamic simulation modelling approach and is linked to the heat supply to calculate the associated primary energy savings. The cost-effectiveness is calculated considering investment costs as well as net present values of energy cost savings when the AHUs are applied. The results show that the primary energy savings and cost-effectiveness for heat recovery AHUs vary considerably for different contexts. The semi-centralised AHUs with rotary heat exchanger seem slightly more cost-effective among the analysed heat recovery configurations. Frost conditions and defrosting need have significant impact on the primary energy and economic performance of the AHUs.
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| 9. |
- Fogelström, Frej, et al.
(författare)
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A review of possibilities and challenges of pit thermal energy storages in Swedish district heating networks
- 2024
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Ingår i: ISEC 2024. - : AEE – Institute for Sustainable Technologies.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of pit thermal energy storages (PTES) enables higher solar fraction in district heating networks by counteracting the mismatch between heat demand and production in solar district heating (SDH) installations. Capital costs linked to land areas with site-specific geological conditions are the deciding factors for PTES constructions. This study investigates non-technical and technical factors for the implementation of PTES in Swedish district heating networks. Having several SDH and PTES installations in operation the country of Denmark is used as a reference. This study, based on literature review, discusses the drivers and challenges for the use of PTES in district heating networks.
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| 10. |
- Fu, Dianliang, et al.
(författare)
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Improved pinch-based method to calculate the capital cost target of heat exchanger network via evolving the spaghetti structure towards low-cost matching
- 2022
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 343
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Tidskriftsartikel (refereegranskat)abstract
- Ahead of heat exchanger network (HEN) design, setting an optimal pinch temperature difference for pinch analysis depends vitally on the capital cost target. Conventional methods based on the spaghetti (SPA) structure ignoring matching optimization might result in calculated cost targets of large deviations. This work evolved the SPA structure via four stages by shifting energy towards low-cost matching. The fourth structure evolved from the SPA structure (ESPA-IV structure) with the lowest-cost matching after loops elimination forms the base to establish the ESPA method. It is validated by numerical experiment and applied to a case reported in literature, meanwhile comparisons are always made to the SPA method. The numerical experiment proves that the ESPA method can obtain capital cost targets with higher accuracy than the SPA method. The target deviations (often within ±5%) given by the ESPA method are much lower than those (well above 10%) derived by the SPA method. In the case study, the given HEN is further optimized as hinted by ESPA method results. Of two target methods, the cost target indicated by ESPA method is closer to the optimum capital cost newly derived after optimization. The high accuracy of the ESPA method is further verified.
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