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Khadra, A., Akander, J. & Myhren, J. A. (2024). Greenhouse Gas Payback Time of Different HVAC Systems in the Renovation of Nordic District-Heated Multifamily Buildings Considering Future Energy Production Scenarios. Buildings, 14(2), Article ID 413.
Open this publication in new window or tab >>Greenhouse Gas Payback Time of Different HVAC Systems in the Renovation of Nordic District-Heated Multifamily Buildings Considering Future Energy Production Scenarios
2024 (English)In: Buildings, E-ISSN 2075-5309, Vol. 14, no 2, article id 413Article in journal (Refereed) Published
Abstract [en]

The European Union (EU) has implemented several policies to enhance energy efficiency. Among these policies is the objective of achieving energy-efficient renovations in at least 3% of EU buildings annually. The primary aim of this study was to offer a precise environmental comparison among four similar district-heated multifamily buildings that have undergone identical energy efficiency measures. The key distinguishing factor among them lies in the HVAC systems installed. The chosen systems were as follows: (1) exhaust ventilation with air pressure control; (2) mechanical ventilation with heat recovery; (3) exhaust ventilation with an exhaust air heat pump; and (4) exhaust ventilation with an exhaust air heat pump with a Photovoltaic (PV) panel. This study involved a life cycle assessment that relied on actual material data from the housing company and energy consumption measurements. This study covered a period of 50 years for thorough analysis. A sensitivity analysis was also conducted to account for various future scenarios of energy production. The findings revealed that the building with an exhaust air heat pump exhibited the lowest greenhouse gas emissions and the shortest carbon payback period (GBPT), needing only around 7 years. In contrast, the building with exhaust ventilation without heat recovery showed the highest emissions and the longest carbon payback period (GBPT), requiring approximately 11 years. Notably, the results were significantly influenced by future scenarios of energy production, emphasizing the crucial role of emission factors in determining the environmental performance of distinct renovation scenarios.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
life cycle assessment; carbon payback time; multifamily buildings; renovation; HVAC systems; future energy production scenarios
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-43800 (URN)10.3390/buildings14020413 (DOI)
Funder
Swedish Energy Agency, 40811-2Swedish Energy Agency
Available from: 2024-02-13 Created: 2024-02-13 Last updated: 2024-02-13Bibliographically approved
Sayadi, S., Akander, J., Hayati, A. & Cehlin, M. (2023). Analysing future cooling demand for a new preschool building in central Sweden. In: Proceedings of the 5th International Conference on Building Energy and Environment: . Paper presented at 5th International Conference on Building Energy and Environment (COBEE2022), Montreal, Canada, July 2022.. Singapore: Springer
Open this publication in new window or tab >>Analysing future cooling demand for a new preschool building in central Sweden
2023 (English)In: Proceedings of the 5th International Conference on Building Energy and Environment, Singapore: Springer, 2023Conference paper, Published paper (Refereed)
Abstract [en]

This study is framed around two research questions to 1) investigate the probable changes in future climate and 2) evaluate the changes in cooling demand of a studied building when implementing an assemble climate representing mid-term future period (2041-2060). The chosen building is a preschool in central Sweden that fulfills the Nearly-Zero Energy Building (NZEB) requirements based on today’s Swedish National Building Regulations. To assess and cope with the present and future cooling energy needs of the building, a climate file representing present conditions along with a projected future typical climate file are utilized. The future climate is an assembled typical meteorological year climate file using the CORDEX data. 

The present climate file underpredicts the future energy demands therefore verifying to be unsuitable for anticipated energy analysis. It was discovered that the cooling demand for assembled climate file is almost 4 times the present climate file for the studied conditions. 

Place, publisher, year, edition, pages
Singapore: Springer, 2023
Series
Environmental Science and Engineering, ISSN 1863-5520, E-ISSN 1863-5539
Keywords
Climate changes, space cooling, building energy simulation
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-39650 (URN)10.1007/978-981-19-9822-5_283 (DOI)2-s2.0-85172736508 (Scopus ID)978-981-19-9821-8 (ISBN)978-981-19-9823-2 (ISBN)
Conference
5th International Conference on Building Energy and Environment (COBEE2022), Montreal, Canada, July 2022.
Funder
Swedish Energy Agency, 48296-1
Available from: 2022-08-03 Created: 2022-08-03 Last updated: 2023-10-09Bibliographically approved
Sayadi, S., Akander, J., Hayati, A., Gustafsson, M. & Cehlin, M. (2023). Comparison of Space Cooling Systems from Energy and Economic Perspectives for a Future City District in Sweden. Energies, 16(9), Article ID 3852.
Open this publication in new window or tab >>Comparison of Space Cooling Systems from Energy and Economic Perspectives for a Future City District in Sweden
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2023 (English)In: Energies, E-ISSN 1996-1073, Vol. 16, no 9, article id 3852Article in journal (Refereed) Published
Abstract [en]

In this study, the performance of different cooling technologies from energy and economicperspectives were evaluated for six different prototype residential Nearly Zero Energy Buildings(NZEBs) within a planned future city district in central Sweden. This was carried out by assessingthe primary energy number and life cycle cost analysis (LCCA) for each building model and coolingtechnology. Projected future climate file representing the 2050s (mid-term future) was employed.Three cooling technologies (district cooling, compression chillers coupled/uncoupled with photovoltaic (PV) systems, and absorption chillers) were evaluated. Based on the results obtained fromprimary energy number and LCCA, compression chillers with PV systems appeared to be favorableas this technology depicted the least value for primary energy use and LCCA. Compared to compression chillers alone, the primary energy number and the life cycle cost were reduced by 13%, onaverage. Moreover, the district cooling system was found to be an agreeable choice for buildingswith large floor areas from an economic perspective. Apart from these, absorption chillers, utilizingenvironmentally sustainable district heating, displayed the highest primary energy use and life cycle cost which made them the least favorable choice. However, the reoccurring operational cost fromthe LCCA was about 60 and 50% of the total life cycle cost for district cooling and absorption chillers,respectively, while this value corresponds to 80% for the compression chillers, showing the high netpresent value for this technology but sensitive to future electricity prices.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
nearly zero energy building (NZEB), primary energy number, district cooling, absorption and compression chillers, life cycle cost analysis, climate-resilient buildings
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-41711 (URN)10.3390/en16093852 (DOI)000987062500001 ()2-s2.0-85159329094 (Scopus ID)
Funder
Swedish Energy Agency, 48296-1Swedish Energy Agency, 2019-003410
Available from: 2023-04-30 Created: 2023-04-30 Last updated: 2023-11-23Bibliographically approved
Khosravi Bakhtiari, H., Sayadi, S., Akander, J., Hayati, A. & Cehlin, M. (2023). How Will Mechanical Night Ventilation Affect the Electricity Use and the Electrical Peak Power Demand in 30 Years? – A Case Study of a Historic Office Building in Sweden. In: Proceedings of the 5th International Conference on Building Energy and Environment: . Paper presented at 5th International Conference on Building Energy and Environment (COBEE2022), Concordia University, Montreal, Canada, 25-29 July 2022. Singapore: Springer
Open this publication in new window or tab >>How Will Mechanical Night Ventilation Affect the Electricity Use and the Electrical Peak Power Demand in 30 Years? – A Case Study of a Historic Office Building in Sweden
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2023 (English)In: Proceedings of the 5th International Conference on Building Energy and Environment, Singapore: Springer, 2023Conference paper, Published paper (Refereed)
Abstract [en]

This study aims at assessing how well a mechanical night ventilation of today, will cope with delivering acceptable thermal comfort while minimizing the electricity use and the electrical peak power demand for cooling in a historic office building in Sweden at both typical current climate and typical future climate in 2050s. The method includes numerical study in IDA-ICE simulation program using the typical current and future climate profiles. The results show that, for coefficient of performance of 3 and specific fan power of 1.5 kW/(m3/s), it would be possible to lower the electrical peak power demand and the electricity use in cooling machine by up to 2.2 kW (13%) and 1.4 MWh (48%) by night ventilation rate of 2.1 lit/(s·m2) at typical future climate in 2050s. Corresponding figures for typical current climate are 4.6 kW (36%) and 0.9 MWh (72%) owing to cooler nights and more diurnal temperature differences. 

Place, publisher, year, edition, pages
Singapore: Springer, 2023
Series
Environmental Science and Engineering, ISSN 1863-5520, E-ISSN 1863-5539
Keywords
Mechanical night ventilation, Future climates, Resilient energy systems, Building energy simulation (BES), IDA Indoor Climate and Energy (IDA-ICE)
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-39651 (URN)10.1007/978-981-19-9822-5_278 (DOI)2-s2.0-85172739094 (Scopus ID)978-981-19-9821-8 (ISBN)978-981-19-9822-5 (ISBN)
Conference
5th International Conference on Building Energy and Environment (COBEE2022), Concordia University, Montreal, Canada, 25-29 July 2022
Funder
Knowledge Foundation, 20150133
Available from: 2022-08-03 Created: 2022-08-03 Last updated: 2023-10-09Bibliographically approved
Attia, S., Benzidane, C., Rahif, R., Amaripadath, D., Hamdy, M., Holzer, P., . . . Carlucci, S. (2023). Overheating calculation methods, criteria, and indicators in European regulation for residential buildings. Energy and Buildings, 292, Article ID 113170.
Open this publication in new window or tab >>Overheating calculation methods, criteria, and indicators in European regulation for residential buildings
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2023 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 292, article id 113170Article in journal (Refereed) Published
Abstract [en]

With the ongoing significance of overheating calculations in the residential building sector, building codes such as the European Energy Performance of Building Directive (EPBD) are essential for harmonizing the indicators and performance thresholds. This paper investigates Europe's overheating calculation methods, indicators, and thresholds and evaluates their ability to address climate change and heat events. e study aims to identify the suitability of existing overheating calculation methods and propose recommendations for the EPBD. The study results provide a cross-sectional overview of twenty-six European countries. The most influential overheating calculation criteria are listed the best approaches are ranked. The paper provides a thorough comparative assessment and recommendations to align current calculations with climate-sensitive metrics. The results suggest a framework and key performance indicators that are comfort-based, multi-zonal, and time-integrated to calculate overheating and modify the EU's next building energy efficiency regulations. The results can help policymakers and building professionals to develop the next overheating calculation framework and approach for the future development of climate-proof and resilient residential buildings.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Indicators, Performance-based, Summer thermal comfort, Thermal discomfort, EPBD, Climate change, Heatwave, Prescriptive
National Category
Energy Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-41869 (URN)10.1016/j.enbuild.2023.113170 (DOI)001025640600001 ()2-s2.0-85159561503 (Scopus ID)
Available from: 2023-05-25 Created: 2023-05-25 Last updated: 2023-07-27Bibliographically approved
Chiesa, G., Teufl, H., Mahdavi, A., Breesch, H., Sengupta, A., Kacanzi, O. B., . . . Heiselberg, P. (2023). Remove sensible heat from indoorenvironments. In: Peter Holzer and Philipp Stern (Ed.), International Energy Agency - Resilient Cooling of Buildings - State of the Art Review: (pp. 130-189). Vienna: Institute of Building Research & Innovation
Open this publication in new window or tab >>Remove sensible heat from indoorenvironments
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2023 (English)In: International Energy Agency - Resilient Cooling of Buildings - State of the Art Review / [ed] Peter Holzer and Philipp Stern, Vienna: Institute of Building Research & Innovation , 2023, p. 130-189Chapter in book (Other academic)
Abstract [en]

The world is facing a rapid increase of air conditioning of buildings. It is the motivation of Annex 80 to develop, assess and communicate solutions of resilient cooling and overheating protection. Resilient Cooling is used to denote low energy and low carbon cooling solutions that strengthen the ability of individuals and our community to withstand, and prevent, thermal and other impacts of changes in global and local climates. It encompasses the assessment and Research & Development of both active and passive cooling technologies of the following four groups:

Reduce heat loads to people and indoor environments.Remove sensible heat from indoor environments.Enhance personal comfort apart from space cooling.Remove latent heat from indoor environments.The present review sums up the state of the art in cooling solutions which may be regarded as resilient. Its main objective is to systematically describe the available cooling solutions, their physical basis, their benefits and limitations, their technology readiness level, their practical availability, and applicability. Doing so, the State-of-the-Art Review forms the basis for the work of Annex 80.

Place, publisher, year, edition, pages
Vienna: Institute of Building Research & Innovation, 2023
Keywords
Resilient cooling, cooling technologies, technology review
National Category
Energy Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-42950 (URN)10.52776/coxk4763 (DOI)
Funder
Swedish Energy Agency, 48296–1
Available from: 2023-08-29 Created: 2023-08-29 Last updated: 2024-01-11Bibliographically approved
Hayati, A., Akander, J. & Eriksson, M. (2022). A case study of mapping the heating storage capacity in a multifamily building within a district heating network in mid-Sweden. Buildings, 12(7), Article ID 1007.
Open this publication in new window or tab >>A case study of mapping the heating storage capacity in a multifamily building within a district heating network in mid-Sweden
2022 (English)In: Buildings, E-ISSN 2075-5309, Vol. 12, no 7, article id 1007Article in journal (Refereed) Published
Abstract [en]

The building sector accounts for a third of the total energy use in Sweden, and district heating provides half of the heating needs. The peak demand loads within a district heating network occur both regularly and irregularly and impose a burden on the energy company to fulfill the demand, often by using more expensive and less environmentally friendly resources (e.g., fossil fuels) instead of the waste heat from industry or biofuels. Heat storage during hours of less demand and prior to colder periods can be used for load management and sustainable planning of energy supply, as well as reduction of total greenhouse gas emissions. Thus, heat supply to the building can be lowered temporarily during the peak power period to utilize the stored thermal energy within the building thermal inertia. The use of indoor temperature decay and the delivery of heating power to a multifamily building are studied here, and heating storage capacity and thermal inertia are calculated. During the performed decay test, the energy supply was estimated to be reduced by 61% for 5 h, which resulted in only a 0.3 °C temperature decay. Therefore, the suggested method can shave eventual peaks in supplied heat with minimal influence on the thermal comfort.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
district heating; load management; peak shaving; thermal storage; energy signature; thermal inertia of buildings; building time constant
National Category
Civil Engineering
Identifiers
urn:nbn:se:hig:diva-39677 (URN)10.3390/buildings12071007 (DOI)000832182900001 ()2-s2.0-85137373611 (Scopus ID)
Funder
Swedish Energy Agency, P2022-00195
Available from: 2022-08-12 Created: 2022-08-12 Last updated: 2024-01-17Bibliographically approved
Sayadi, S., Akander, J., Hayati, A. & Cehlin, M. (2022). Analyzing the climate-driven energy demand and carbon emission for a prototype residential nZEB in central Sweden. Energy and Buildings, 261, Article ID 111960.
Open this publication in new window or tab >>Analyzing the climate-driven energy demand and carbon emission for a prototype residential nZEB in central Sweden
2022 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 261, article id 111960Article in journal (Refereed) Published
Abstract [en]

The changes in climate and the expected extreme climate conditions in the future, given the long life span of the buildings have pushed the design limits. In this study, the changes in primary energy use (PEPET), total energy use and CO2 emission were investigated for a prototype residential building. The building fulfils nearly zero energy building (NZEB) characteristics, imposed by the Swedish building regulations. Different cooling technologies and various typical meteorological year (TMY) climate files assembled for different periods, as well as automatic shading were investigated. The assembled TMY files advocated for the present (2001-2020) and mid-future (2041-2060) period using the CORDEX data. Different cooling methods and set-points (24-28°C) were defined to evaluate the cooling energy requirement changes.

It was discovered that the freely available typical climate file fails to cover the induced changes in climate and its extreme implications on the building. The required cooling energy use increased from 1.7-5.8 times the freely available climate file, when using the projected TMY and the extreme climate files.

Addition of automatic shading system reduced cooling energy up to 75% within the studied cooling methods and set-points. Moreover PEPET and CO2 emission also decreased for the studied cooling methods, climate and weather files.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Future climate file, extreme weather file, building performance simulation, primary energy number, carbon emission
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-38005 (URN)10.1016/j.enbuild.2022.111960 (DOI)000800422900010 ()2-s2.0-85125273703 (Scopus ID)
Funder
Swedish Energy Agency, 48296-1
Available from: 2022-02-22 Created: 2022-02-22 Last updated: 2022-06-23Bibliographically approved
Sayadi, S., Hayati, A., Akander, J. & Cehlin, M. (2022). Cooling Demand Reduction Approaches in a Nearly Zero Energy Building for Future City District in Central-Sweden. In: Building Simulation Conference Proceedings: . Paper presented at 17th IBPSA Conference on Building Simulation, BS 2021, Bruges, Belgium, 1-3 September 2021 (pp. 1413-1420). IBPSA
Open this publication in new window or tab >>Cooling Demand Reduction Approaches in a Nearly Zero Energy Building for Future City District in Central-Sweden
2022 (English)In: Building Simulation Conference Proceedings, IBPSA , 2022, p. 1413-1420Conference paper, Published paper (Refereed)
Abstract [en]

The increase in population and living standards, as well as global warming and heatwaves due to climate change, have created a challenge to meet the cooling demand in buildings. In this study, the cooling requirement for a multifamily building through simulations in a future city district in central-Sweden was determined. Different air supply set point strategies, window to floor ratio and building rotations were employed to minimize the cooling requirements. The building was modelled so as to meet the Nearly Zero Energy Building (NZEB) requirements. Window to floor ratio of 10% with a piecewise proportional controller for supply temperature was depicted as appropriate for the building. A 45° rotation of the building increased the cooling demand. The cooling demand of the building increased by employing the extreme climate condition, as a representative for future climate, with factors 3.8 and 6.4 for cooling set points 25°C and 27°C for window to floor ratio 10%. This implies the need for a resilient building to withstand future climate conditions. The requirement to update the climate files was also used for decision making in the design process and building regulation. 

Place, publisher, year, edition, pages
IBPSA, 2022
Keywords
Building simulation, multi-family buildings, energy efficiency measure, future weather
National Category
Civil Engineering
Identifiers
urn:nbn:se:hig:diva-41603 (URN)10.26868/25222708.2021.30327 (DOI)2-s2.0-85151521359 (Scopus ID)9781775052029 (ISBN)
Conference
17th IBPSA Conference on Building Simulation, BS 2021, Bruges, Belgium, 1-3 September 2021
Available from: 2023-04-17 Created: 2023-04-17 Last updated: 2023-09-10Bibliographically approved
Hayati, A. & Akander, J. (2022). Influence of energy units in building certification system, Miljöbyggnad: A case study of a school building in Sweden. In: Proceedings of the 5th International Conference on Building Energy and Environment (COBEE 2022): . Paper presented at COBEE 2022, Concordia University, Montreal, Canada, 25-29 July 2022. , Article ID 1391.
Open this publication in new window or tab >>Influence of energy units in building certification system, Miljöbyggnad: A case study of a school building in Sweden
2022 (English)In: Proceedings of the 5th International Conference on Building Energy and Environment (COBEE 2022), 2022, article id 1391Conference paper, Published paper (Refereed)
Abstract [en]

The Swedish environmental assessment certification system Miljöbyggnad rewards lower energy use in comparison to that of building regulations, related to total heated floor area. Previous studies suggest that this indicator shows the efficiency of the technical design of the building; not how well the building is utilized. Thus, a more suitable quantity/unit can be the one that takes into account the extent of how the building is used in a more efficient and sustainable way. The aim of this paper is to discuss if current energy units are sustainable enough to assess efficient use of buildings and investigate how indicators can affect the grades and criteria of a certification system. Normalization of simulated energy use of a school building, by using the total heated floor area, the total building’s enclosing area, number of occupants and the schedule of occupancy, give different results. 

Keywords
Miljöbyggnad, Environmental Assessment Certification system, IDA Indoor Climate Energy simulation (IDA-ICE), Primary Energy use, Building energy use
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-40544 (URN)10.1007/978-981-19-9822-5_89 (DOI)2-s2.0-85172732178 (Scopus ID)9789811998218 (ISBN)
Conference
COBEE 2022, Concordia University, Montreal, Canada, 25-29 July 2022
Funder
Swedish Energy Agency, 2018–016216
Available from: 2022-12-01 Created: 2022-12-01 Last updated: 2023-10-09Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9076-0801

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