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  • 1.
    Akander, Jan
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Khosravi Bakhtiari, Hossein
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Hayati, Abolfazl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    The City Hall in Gävle, Sweden: A historic office building2024Inngår i: International Energy Agency - Resilient Cooling of Buildings Field Studies Report (Annex 80): Energy in Buildings and Communities Technology Collaboration Programme, Vienna: Institute of Building Research & Innovation , 2024, s. 173-187Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This IEA Annex 80 Subtask C report and the associated brochures provide examples of well-documented field studies. These field studies apply resilient cooling technologies to reduce energy demand and carbon emissions for cooling and reduce the overheating risk in different types of buildings, including newly constructed and existing buildings. Examples and details on building information, energy systems, resilient cooling technologies, key performance indicators (KPIs), and performance evaluation amd lessons learned are included in the report and the brochures.

    The present report summarizes all 13 field study buildings collected in Subtask C of IEA-EBC Annex 80. This summary presents information on the field studies, the resilient cooling technologies applied in the field studies, the KPIs, and the performance evaluation and lessons learned. The values of KPIs for building similar functions, i.e., residential buildings, under different climate conditions were discussed. In the field study brochures, detailed information is inlcuded for each building.

    The field studies are presented in brochure format. Each brochure contains information in a standardized format. This includes the introduction & climate, building information, resilient cooling, KPI evaluation, design simulation, performance evaluation, discussion, lessons learned, references & key contacts.

  • 2.
    Attia, Shady
    et al.
    Université de Liège, Belgium.
    Benzidane, Caroline
    Grenoble INP University of Grenoble Alpes, France.
    Rahif, Ramin
    Université de Liège, Belgium.
    Amaripadath, Deepak
    Université de Liège, Belgium.
    Hamdy, Mohamed
    Norwegian University of Science and Technology (NTNU), Norway.
    Holzer, Peter
    Institute of Building Research & Innovation, Vienna, Austria.
    Koch, Annekatrin
    Darmstadt University of Technology, Germany.
    Maas, Anton
    University of Kassel, Germany.
    Moosberger, Sven
    Equa Solutions AG, Switzerland.
    Petersen, Steffen
    Aarhus University, Denmark.
    Mavrogianni, Anna
    University College London, United Kingdom.
    Maria Hidalgo-Betanzos, Juan
    University of the Basque Country UPV/EHU, Spain.
    Almeida, Manuela
    University of Minho Department of Civil Engineering, Portugal.
    Akander, Jan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Khosravi Bakhtiari, Hossein
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Kinnane, Olivier
    University College Dublin, Dublin, Ireland.
    Kosonen, Risto
    Aalto University, Finland.
    Carlucci, Salvatore
    Overheating calculation methods, criteria, and indicators in European regulation for residential buildings2023Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 292, artikkel-id 113170Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 3.
    Bakhtiari, Hossein
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Evaluation of Thermal Comfort and Night Ventilation in a Historic Office Building in Nordic Climate2020Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Envelopes with low thermal performance are common characteristics in European historic buildings resulting in insufficient thermal comfort and higher energy use compared to modern buildings. There are different types of applications for the European historic buildings such as historic churches, historic museums, historic theatres, etc. In historic buildings refurbished to offices, it is vital to improve thermal comfort for the staff. Improving thermal comfort should not increase, preferably reduce, energy use in the building.

    The overall aim in this research is to explore how to improve thermal comfort in historic buildings without increasing, preferably reducing, energy use with the application of non-intrusive methods. This is done in form of a case study in Sweden. Thermal comfort issues in the case study building are determined through a field study. The methods include field measurements with thermal comfort equipment, data logging on BMS, and evaluating the occupant’s perception of a summer and a winter period indoor environment using a standardized questionnaire. According to questionnaire and thermal comfort measurements results, it is revealed that the summer period has the most dissatisfied occupants, while winter thermal comfort is satisfactory – but not exceptionally good.

    Accordingly, natural heat sinks could be used in form of NV, as a non/intrusive method, in order to improve thermal comfort in the building. For the historic building equipped with mechanical ventilation, NV strategy has the potential to both improve thermal comfort and reduce the total electricity use for cooling (i.e. electricity use in the cooling machine + the electricity use in the ventilation unit’s fans). It could decrease the percentage of exceedance hours in offices by up to 33% and reduce the total electricity use for cooling by up to 40%. The optimal (maximum) NV rate (i.e. the potential of NV strategy) is dependent on the thermal mass capacity of the building, the available NV cooling potential (dependent on the ambient air temperature), COP value of the cooling machine, the SFP model of the fans (low SFP value for high NV rate is optimal), and the offices’ door scheme (open or closed doors).

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  • 4.
    Khosravi Bakhtiari, Hossein
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Construction, Gavlefastigheter Company, Gävle, Sweden.
    Akander, Jan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Evaluation of Thermal Comfort in a Historic Building Refurbished to an Office Building with Modernized HVAC Systems2020Inngår i: Advances in Building Energy Research, ISSN 1751-2549, E-ISSN 1756-2201, Vol. 14, nr 2, s. 218-237Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Envelopes with low thermal performance are common characteristics in European historic buildings, causing higher energy demand and insufficient thermal comfort. This paper presents the results of a study on indoor environmental quality (IEQ), with special focus on thermal comfort, in the historic City Hall of Gävle, Sweden, now used as an office building. There are two modern heat recovery ventilation systems with displacement ventilation supply devices. The district heating network heats the building via pre-heat supply air and radiators. Summer cooling comes from electric heat pump ejecting heat into the exhaust ventilation air. A building management system (BMS) controls the heating, ventilation and air-conditioning (HVAC) equipment. The methodology included on-site measurements, BMS data logging and evaluating the occupants’ perception of a summer and a winter period indoor environment using a standardized questionnaire. In conclusion, indoor environmental quality in this historic building is unsatisfactory. Stuffy air, too high, too low and varying room temperatures, lighting problems and noise are constant issues. Although it is equipped with modern ventilation systems, there are still possibilities for improving thermal comfort by improved control strategies, since upgrading the building’s envelope is not allowed according to the Swedish Building Regulations in historic buildings with heritage value.

  • 5.
    Khosravi Bakhtiari, Hossein
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Akander, Jan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Hayati, Abolfazl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    On the Performance of Night Ventilation in a Historic Office Building in Nordic Climate2020Inngår i: Energies, E-ISSN 1996-1073, Vol. 13, nr 16, artikkel-id 4159Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of mechanical night ventilation on thermal comfort and electricity use for cooling of a typical historic office building in north-central Sweden was assessed. IDA-ICE simulation program was used to model the potential for improving thermal comfort and electricity savings by applying night ventilation cooling. Parametric study comprised different outdoor climates, flow rates, cooling machine’s coefficient of performance and ventilation units’ specific fan power values. Additionally, the effect of different door schemes (open or closed) on thermal comfort in offices was investigated. It was shown that night ventilation cannot meet the building’s total cooling demand and auxiliary active cooling is required, although the building is located in a cold climate. Night ventilation had the potential in decreasing the percentage of exceedance hours in offices by up to 33% and decreasing the total electricity use for cooling by up to 40%. More electricity is saved with higher night ventilation rates. There is, however, a maximum beneficial ventilation rate above which the increase in electricity use in fans outweighs the decrease in electricity use in cooling machine. It depends on thermal mass capacity of the building, cooling machine´s coefficient of performance, design ventilation rate, and available night ventilation cooling potential (ambient air temperature).

    Fulltekst (pdf)
    fulltext
  • 6.
    Khosravi Bakhtiari, Hossein
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Department of Construction, Gavlefastigheter Company, Gävle, Sweden.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Akander, Jan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Thermal Comfort in Office Rooms in a Historic Building with Modernized HVAC Systems2018Inngår i: Proceedings of the 4th International Conference On Building Energy & Environment, COBEE 2018: RMIT University, Melbourne, Australia, Feb 5-9th 2018 / [ed] Kiao Inthavong,Chi Pok Cheung, Guan Yeoh, Jiyuan Tu, Melbourne: Conference On Building Energy & Environment , 2018, s. 683-688, artikkel-id 230Konferansepaper (Fagfellevurdert)
    Abstract [en]

    SUMMARY

    Envelopes with low thermal performance are common characteristics in European historic buildings, leading to higher energy demand and insufficient thermal comfort. This paper presents the results of a study on thermal comfort in the historic office building of City Hall in Gävle, Sweden. It is equipped with two modern heat recovery ventilation systems with displacement ventilation supply devices in offices. District heating network heats the building via pre-heat supply air and radiators. Summer cooling comes from electric heat pump, rejecting heat into the exhaust ventilation air. A building management system controls HVAC equipment. Methodology includes on-site measurements, data logging on management system and evaluating the occupants’ perception of a summer and a winter period indoor environment using a standardized questionnaire. In conclusion, thermal comfort in this historic building is poor although it is equipped with modern ventilation systems and there should be possibilities for improving comfort, by improved control strategies.

    Keywords — Historic Buildings, On-site Measurements, Standardized Questionnaire, Thermal Comfort

  • 7.
    Khosravi Bakhtiari, Hossein
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Gavlefastigheter AB.
    Sayadi, Sana
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Akander, Jan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Hayati, Abolfazl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    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 Sweden2023Inngår i: Proceedings of the 5th International Conference on Building Energy and Environment, Singapore: Springer, 2023Konferansepaper (Fagfellevurdert)
    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. 

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