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  • 1.
    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
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Khosravi Bakhtiari, Hossein
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    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 buildings2023In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 292, article id 113170Article in journal (Refereed)
    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.

  • 2.
    Blomqvist, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Conversion of Electric Heating in Buildings: an Unconventional Alternative2008In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 40, no 12, p. 2188-2195Article in journal (Refereed)
    Abstract [en]

    To decrease the electric energy used for heating buildings it has become desirable to convert direct electrical heating to other heat sources. This paper reports on a study of the possibility of using an unconventional method for conversion to avoid installing an expensive hydronic system. The conversion method combines the ventilation and heating systems and uses air instead of water for distribution of heat within the building, taking advantage of thermal forces and the special properties of gravity currents. Full-scale tests have been carried out in a test apartment inside a laboratory hall where the conditions could be controlled. Temperatures and efficiency of ventilation have been measured to ensure that the demands with respect to thermal climate and air exchange were fulfilled. The results show that it is possible to use the method for heating and ventilation when converting the heating system, but further work has to be done to develop a detailed solution that works in practice.

  • 3.
    Cehlin, Mathias
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Measurements of air temperatures close to a low-velocity diffuser in displacement ventilation using an infrared camera2002In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 34, no 7, p. 687-698Article in journal (Refereed)
    Abstract [en]

    The near zone of supply air diffusers is very critical for the indoor climate. Complaints of draft are often associated with low-velocity diffusers in displacement ventilation because the air is discharged directly into the occupied zone. Today, the knowledge of the near zone of these air supply diffusers is insufficient, causing an increased need for better measuring methods and representation of the occupied zone.

    A whole-field measuring technique has been developed by the authors for visualization of air temperatures and airflow patterns over a large cross-section. In this particular whole-field method, air temperatures are measured with an infrared camera and a measuring screen placed in the airflow. The technique is applicable to most laboratory and field test environments. It offers several advantages over traditional techniques; for example, it can record real-time images within large areas and capture transient events.

    The purpose of this study was to conduct a parameter and error analysis of the proposed whole-field measuring method applied to a flow from a low-velocity diffuser in displacement ventilation. A model of the energy balance, for a solid measuring screen, was used for analyzing the influence of different parameters on the accuracy of the method. The analysis was performed with respect to the convective heat transfer coefficient, emissivity, screen temperature and surrounding surface temperatures.

    Theoretically, the temperature difference between the screen and the ambient air was found to be 0.2–2.4 °C for the specific delimitation in the investigation. However, after applying correction the maximum uncertainty of the predicted air temperature was found to vary between 0.62 and 0.98 °C, due to uncertainties in estimating parameters used in the correction. The maximum uncertainty can be reduced to a great extent by estimating the convective heat transfer coefficient more accurately and using a screen with rather low emissivity.

  • 4. Erell, E
    et al.
    Etizon, Y
    Carlstrom, N
    Sandberg, Mats
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Molina, J
    Maestre, I
    Maldonado, E
    Leal, V
    Gutschker, O
    "SOLVENT": development of a reversible solar-screen glazing system2004In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 36, no 5, p. 467-480Article in journal (Refereed)
    Abstract [en]

    Preliminary experiments with a novel glazing system developed at the Desert Architecture and Urban Planning Unit of Ben-Gurion University of the Negev in Israel indicated that it may provide improved visual and thermal performance in buildings with large glazed areas located in sunny regions, regardless of orientation. In winter, it reduces glare, local over-heating and damage to furnishings caused by exposure to direct solar radiation, with only a small reduction in solar space heating. In summer, it reduces the penetration of unwanted radiation without obstructing the view through the window, to an extent that may render external shading devices unnecessary. The SOLVENT project was contracted to complete the development of the glazing system, which is based on the concept of converting short-wave solar radiation to convective heat and long wave radiation. The glazing system was modeled and evaluated experimentally; a suitable frame was developed for it; and a design tool required for its application was developed. The current paper reports on physical modeling and experimental evaluation of the glazing system.

  • 5.
    Eriksson, Martin
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Akander, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköpings universitet.
    Development and validation of energy signature method – Case study on a multi-family building in Sweden before and after deep renovation2020In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 210, article id 109756Article in journal (Refereed)
    Abstract [en]

    Building energy use constitutes a large part of total energy use, both in the European Union and Sweden. Due to this energy use, and the resulting emissions, several goals for energy efficiency and emissions have been set. In Sweden, a large portion of multi-family buildings were built between 1960 and 1980, which have major energy savings potential. The purpose of this paper is further development and validation of previously introduced energy signature method and its inherent parameters. The method was applied on a multi-family building where thermal energy data supplied by the district heating company was available before and after deep renovation. Using IDA ICE, a building energy simulation (BES) software model was created of the building, to aid in validation of the energy signature method. The paper highlighted the accuracy of the proposed energy signature (PES) method and a sensitivity analysis on the inherent parameters have been performed. The results showed new ways of treatment of the thermal energy data and revealed how more information can be extracted from this data.

  • 6. Ghadimi, M.
    et al.
    Ghadamian, H.
    Hamidi, A. A.
    Shakouri, M.
    Ghahremanian, Shahriar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Division of Energy Systems, Department of Management and Engineering, Linköping University, Sweden.
    Numerical analysis and parametric study of the thermal behavior in multiple-skin facades2013In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 67, p. 44-55Article in journal (Refereed)
    Abstract [en]

    The general aim of this research is contributed to the energy performance assessment of single storey multiple-skin facade. To cover this aim; multiple skin facade are studied by means of experiments and numerical simulation. In this research a numerical model for multiple-skin facades with mechanical and natural ventilation has been developed. The numerical model is two-dimensional and based on a cell centered volume method (CVM). As an improvement, radiation and convection are treated separately and by this means an innovative method is applied to calculate the view factors and heat transfer coefficients between surfaces and each cavity. Then the developed numerical model is validated using measurements from the vliet test building. However, there is no multiple-skin facade application in Tehran. Thus the model is used to assess the influence of different multiple-skin facade parameters in Tehran's climate conditions to show its effect on heat losses if this technology would be applied. As a consequence of the diversity of results, designer should be aware that multiple-skin facades do not necessarily improve the energy efficiency of their designs. (C) 2013 Elsevier B.V. All rights reserved.

  • 7.
    Gustafsson, Mattias
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Gävle Energi AB, Gävle, Sweden.
    Karlsson, Björn
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Rönnelid, Mats
    Högskolan Dalarna.
    How the electric meter configuration affect the monitored amount of self-consumed and produced excess electricity from PV systems: case study in Sweden2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 138, p. 60-68Article in journal (Refereed)
    Abstract [en]

    This study evaluates how the principal function of bi-directional electric meters affects the monitored amount of self-consumed and produced excess electricity for dwelling buildings connected to the grid by three phases. The electric meters momentarily record the sum of the phases or the phases individually and then summarize the recorded values to a suitable time period and is then collected by the grid owner. In Sweden, both electric meter configurations fulfill laws and regulations.

    The meter configuration affects the monitored distribution of self-consumed and produced excess electricity significantly for the investigated single-family house but is negligible for the investigated multi-dwelling buildings. The monitored self-consumed electricity produced by the PV installation for the single-family house varies between 24% and 55% depending on the configuration and how the inverter is installed for the investigated year. The difference in economic value for the produced electricity varies between 79.3 to 142 Euros.

    Due to the electric meter configuration, the profitability of PV systems will be different for identical single-family houses with identical conditions. This should be corrected for a well-functioning market. It is also important to decide how the configuration should be designed to ensure that different incentives and enablers results in desired effects.

  • 8.
    Hayati, Abolfazl
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Mattsson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Single-sided ventilation through external doors: measurements and model evaluation in five historical churches2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 141, p. 114-124Article in journal (Refereed)
    Abstract [en]

    Ventilation through open doors is a simple way to temporarily enhance ventilation of indoor spaces, with the purpose to evacuate indoor air pollutants or to adjust the indoor temperature. In churches and other historical buildings, which otherwise are ventilated only through air infiltration, temporarily enhanced ventilation through open doors or windows may be a prudent deed after e.g. services involving large congregations and burning of candles or incense. In the present study, the air exchange occurring at single-sided ventilation through the external doors of five historical churches is measured by tracer gas decay method. Further, air velocity measurements and smoke visualization in a doorway are performed. Measurement results are compared with predictions attained from four previously developed models for single‐sided ventilation. Models that include terms for wind turbulence yielded somewhat better predictions. According to the performed measurements, the magnitude of one hour single-sided open-door airing in a church is typically around 50% air exchange, indicating that this is a workable ventilation method, also for such large building volumes. A practical diagram to facilitate estimation of a suitable airing period is also presented. The study adds particularly knowledge to the issue of airing through doors, in large single zones.

  • 9.
    Hed, Göran
    et al.
    University of Gävle, Department of Technology and Built Environment.
    Bellander, R
    Mathematical modelling of PCM air heat exchanger2006In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 38, no 2, p. 82-89Article in journal (Refereed)
    Abstract [en]

    In order to cool a room with a cold night air phase change material, PCM, is stored in an air heat exchanger. During night the PCM crystallises, energy is released. During daytime air is circulated in the unit, energy is absorbed and the indoor air is cooled. The characteristic of PCM is that there is an increase of the specific heat over a limited temperature span. This is the principle that is used in the design of the PCM air heat exchanger unit. The action of a PCM storage unit will act differently depending of the thermal properties of the material. In an ideal material the phase transition occurs at a given temperature. On the market, compounds containing PCM are available which, in order to create a suitable melting temperature, are mixtures of different products. In these materials, the transition from liquid to solid takes place over a temperature span, i.e. the specific heat varies with the temperature. This can be represented by a c(p)(T) curve, specific heat as a function of the temperature. In this paper, the development of a mathematical model of the PCM air heat exchanger is presented. Considerations are taken to different shapes of the cp(T) curve. The mathematical model is verified with measurement on a prototype heat exchanger. The development of the equipment is part of the CRAFT project Changeable Thermal Inertia Dry Enclosures (C-TIDE) the possibility of use of phase change materials integrated into a building is explored. 

  • 10.
    Jiang, Zitao
    et al.
    Osaka University, Japan..
    Kobayashi, Tomohiro
    Osaka University, Japan..
    Yamanaka, Toshio
    Osaka University, Japan..
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    A literature review of cross ventilation in buildings2023In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 291, article id 113143Article in journal (Refereed)
    Abstract [en]

    There is a growing body of literature that recognizes that natural ventilation plays avital role in indoor air quality, thermal comfort and building energy consumption. This papersystematically reviews the previously published research of the most efficient and typical naturalventilation type - cross ventilation, aiming to present the main research topics in contemporaryresearch and provide an agenda for future studies. The methodologies, airflow pattern, ventilationmodels and influencing parameters of cross ventilation were comprehensively summarized anddiscussed. The chained analysis and data-driven methods are the potential approaches to study crossventilation more efficiently. The comparisons of different ventilation models of cross ventilationhelp to better understand the basic mechanisms that drive the cross ventilation airflow.

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  • 11.
    Karami, Peyman
    et al.
    KTH.
    Twumasi Afriyie, Ebenezer
    KTH.
    Norberg, Peter
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering. KTH.
    Gudmundsson, Kjartan
    KTH.
    A study of the thermal conductivity of granular silica materials for VIPs at different levels of gaseous pressure and external loads2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 85, p. 199-211Article in journal (Refereed)
    Abstract [en]

    Fast and reliable methods for the determination of thermal properties of core materials for vacuum insu-lation panels (VIPs) are needed. It is of great importance to know the thermal performance of a VIP core atdifferent levels of vacuum and external loads. In this study a new self-designed device, consisting of twocylindrical cavities connected to a Transient Plane Source instrument, is used to determine the thermalconductivity of low-density nanoporous silica powders, from atmospheric pressure down to 0.1 mbarwhile applying different levels of external pressure up to 4 bars. The study includes a brief theoreticaldiscussion of methods. The TPS is validated through comparison with available data for commercial silicaas well as through independent stationary measurements with a hot plate apparatus and with a TransientHot Bridge method. The different materials illustrate clear but different trends for the thermal conductiv-ity as a function of the level of vacuum and external pressure. The analysis of experimental results showsthat the transient methods are less suitable for measuring the thermal conductivity of low-density sil-ica powders, especially for the cases when the density is less than a limit at which the heat transfer byradiation becomes dominant compared to pure conduction.

  • 12.
    Khadra, Alaa
    et al.
    Högskolan Dalarna.
    Hugosson, Mårten
    Inland Norway University of Applied Sciences.
    Akander, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Myhren, Jonn Are
    Högskolan Dalarna.
    Economic performance assessment of three renovated multi-family buildings with different HVAC systems2020In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 224, article id 110275Article, review/survey (Refereed)
    Abstract [en]

    The EU has adopted several policies to improve energy efficiency. One of these policies aims to achieve energy efficient renovations in at least 3% annually of buildings in EU. The aim of this study was to provide an accurate economic comparison between three similar multi-family buildings that have undergone the same energy efficiency measures, with essential differences regarding the installed ventilation systems. The selected ventilation systems were: 1) balanced mechanical ventilation with heat recovery; 2) exhaust ventilation with air pressure control; and 3) exhaust ventilation with an exhaust air heat pump. In the latter two cases, radiators pre-heat supply air. Life cycle cost analysis were conducted using real investment and operational costs for the three buildings. Sensitivity analysis was also made for different discount rates and energy price escalation patterns. It was found that the building with exhaust ventilation has the lowest life cycle cost. At 2% inflation rate, 3% real discount rate and 1% real energy price escalation, the building with exhaust air heat pump and the building with mechanical ventilation with heat recovery has 13% and 29% higher life cycle cost than the building with exhaust ventilation, respectively. The sensitivity analysis further showed that a lower discount rate gives higher future costs and gives more profitability of systems with heat recovery with lower future costs. Energy price assumptions have a crucial impact on the results and change the profitability of studied renovation packages.

  • 13.
    La Fleur, Lina
    et al.
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Rohdin, Patrik
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Measured and predicted energy use and indoor climate before and after a major renovation of an apartment building in Sweden2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 146, p. 98-110Article in journal (Refereed)
    Abstract [en]

    This article presents a case study of a renovated Swedish apartment building with a common design built in 1961. The aim is to present numerical predictions, validation and evaluation of energy use and indoor climate for the building before and after renovation. Comprehensive field measurements were carried out before and after the renovation to be used as input data in the building energy simulation tool IDA ICE and for validation of model results. Indoor temperature is predicted with maximum standard deviation of 0.4 °C during winter. Annual heat demand is in good agreement with measurements. The building had an annual climate normalized district heat demand of 99.0 MWh before renovation and 55.4 MWh after, resulting in a 44% reduction. A slight under-prediction of the saving potential is noted, since the indoor air temperature has increased after the renovation. The results also show that assumptions of user behavior have significant impact on the energy-saving potential, and that choice of renovation measures, such as level of insulation, and efficiency of the ventilation heat recovery system need careful consideration. Choice of system boundaries also has a major effect on climate and resource impact from selected renovation measures. 

  • 14.
    La Fleur, Lina
    et al.
    Linköpings universitet.
    Rohdin, Patrik
    Linköpings universitet.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköpings universitet.
    Investigating cost-optimal energy renovation of a multifamily building in Sweden2019In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 203, article id 109438Article in journal (Refereed)
    Abstract [en]

    A significant reduction in energy use in the building stock is a major challenge for the future, and doing this in a cost-effective manner is important. This study uses an optimization approach to identify life cycle cost (LCC) optimal energy efficiency measures (EEMs) to implement as part of a renovation of a multifamily building in Sweden. The studied building is a multifamily building with a lightweight concrete construction and an exhaust air ventilation system, built in 1961. The optimization tool OPERA-MILP is used. The energy renovation approaches are compared to both the performed energy renovation of the building and a validated dynamic energy simulation model in IDA ICE 4.8. The results show that under the given framework conditions and assumptions it is not cost-optimal to improve the thermal performance of the building envelope or to implement heat recovery ventilation measures to reduce the space heating demand in the building when considering a life cycle of 40 years. Balanced mechanical ventilation system with heat recovery is cost-effective when an energy saving target of 40% is introduced. The energy renovation of the building has a slightly higher LCC than the cost-optimal level, and it would have been more cost-effective to add more insulation to the façade instead of the attic to achieve the same level of energy saving. A sensitivity analysis has been performed to reveal the effect of the discount rate, energy price, cost of EEMs, thermal properties of the building envelope and windows’ solar heat gain factors on the LCC.

  • 15.
    Larsson, Ulf
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Sandberg, Mats
    University of Gävle, Department of Technology and Built Environment.
    Thermal analysis of super insulated windows (numerical and experimental investigations)1999In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 29, no 2, p. 121-128Article in journal (Refereed)
    Abstract [en]

    Windows are crucial for people's experience of the indoor climate, especially in the Nordic countries with cold climate and short days during the winter. This paper reports the first results from an ongoing research project focused on an improved integration of windows with the indoor air climate and people's perception of the windows. The thermal performance of a well-insulated window has been investigated both numerically and experimentally in a full scale test room. The window under consideration is a low-emissive triple-glazing window with two closed spaces filled with the inert gas krypton. An oxidised metal with low emissivity factor coats one pane in each space. Experimental and numerical investigations on the thermal performance of the window have been conducted for different winter cases. Temperature data obtained by direct temperature measurement using thermocouples and through numerical analysis are presented. The heat transfer through a window construction depends on three mechanisms i.e., conduction, convection and radiation. In this paper the convection-conducting mechanisms have been closely investigated. The numerical predictions agree well with the results from the measurements.

  • 16.
    Liu, Linn
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Akander, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Comprehensive investigation on energy retrofits in eleven multi-family buildings in Sweden2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 84, p. 704-715Article in journal (Refereed)
    Abstract [en]

    Rapidly growing energy use in the building sector is considered a serious problem by both the European Union (EU) and Sweden. Reducing energy demand in the building sector is important for Sweden in order to reach national energy goals for reduced energy use and CO 2 emissions in the future. This project aims to find energy efficiency potential in multifamily buildings in the Gävleborg region, which is a cold climate region in Sweden. Measurements and simulations have been made on eleven multifamily buildings from the whole region. The results include different energy efficiency measure packages, profitability analysis of individual measures and packages, and primary energy use analysis. The paper also includes CO 2 emissions reduction analysis based on different methods. The project shows that the multifamily buildings in the Gävleborg region have good potential to reduce their energy use by more than 50%, which in turn will contribute to 43% primary energy reduction and 48% CO 2 emissions reduction. 

  • 17.
    Liu, Linn
    et al.
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Sweden.
    Rohdin, Parrik
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Sweden.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University, Sweden.
    Investigating cost-optimal refurbishment strategies for the medieval district of Visby in Sweden2018In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 158, p. 750-760Article in journal (Refereed)
    Abstract [en]

    This paper presents a methodology, using Life Cycle Cost (LCC) optimization and building categorization, to achieve a systematic study of the cost-optimal energy efficiency potential (CEEP) for 920 listed buildings in the medieval district of Visby in Sweden. The aim is to study the CEEP and CO2 emission reductions for this city that is included in the World Heritage List by UNESCO. The total CEEP is found to be 31% (20.6 GWh) resulting in a CO2 reduction of 57% (33.3 kton). The categorization method showed that the buildings could be divided in four clusters depending on building material, geometry and layout. The LCC analysis revealed that the energy efficiency measure packages were cluster specific. It is shown that multi-story wood buildings (Cluster II) have lowest specific LCC, and would arguably be the starting point for a renovation process. Presently most of the studied buildings are connected to the district heating (DH). The results show that heat pump (HP) and wood boiler (WB) is cost-optimal heating system for multi-story stone and wood buildings, respectively. In order for the DH to compete with HP and WB, the DH price needs to be reduced by 23% and 16%.

  • 18.
    Liu, Linn
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Rohdin, Patrik
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Evaluating indoor environment of a retrofitted multi-family building with improved energy performance in Sweden2015In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 102, p. 32-44Article in journal (Refereed)
    Abstract [en]

    The building sector within both the EU and Sweden accounts for about 40% of total energy use. It is therefore important to introduce energy efficiency measures in this sector in order to meet the national implementation of the Building Performance Directive. Retrofits that result in improved energy performance are important in order to meet national energy targets, but the impact on the indoor environment has to be considered. Properly chosen energy efficiency measures may affect the indoor environment positively. One retrofitted multi-family building, located in the city of Linköping, Sweden, was chosen as the study object. The building represents a common type of construction in Sweden. This study presents an evaluation of both the indoor environment and energy use of the retrofitted building in comparison with a similar non-retrofitted building from the same area. The results show that the building has potential to reach a 39% reduction of space heating demand. The indoor environment has been improved compared to the non-retrofitted building. Adding external blinds from 15 May to 15 September between 10am-12pm on the east side and 12pm-3pm on the west side seems to be the best option for improving the indoor climate during summer. 

  • 19.
    Liu, Linn
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University, Sweden.
    Rohdin, Patrik
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Sweden.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University, Sweden.
    LCC assessments and environmental impacts on the energy renovation of a multi-family building from the 1890s2016In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 133, p. 823-833Article in journal (Refereed)
    Abstract [en]

    The 2020 and 2050 energy targets increase requirements on energy performance in the building stock, thus affecting both listed and non-listed buildings. It is important to select appropriate and cost-optimal energy efficiency measures, using e.g. Life Cycle Cost (LCC) optimization. The aim of this paper is to find cost-optimal packages of energy efficiency measures (EEMs) as well as to explore the effects of specific predesigned energy target values for a listed Swedish multi-family building from the 1890s. The purpose is also to show the effects on energy use, LCC, primary energy use and CO2 emissions of different energy targets, discount rates, electricity prices and geographic locations. The results show that separate energy targets could be an effective way to simplify the implementation for listed buildings. Furthermore, a cost-optimal package of EEMs is more sensitive to changes in discount rate than in electricity price. The energy renovation has impact on the primary energy use and CO2 emissions. The lower the discount rate is, the more EEMs will be implemented and the easier the national energy targets may be achieved. A higher electricity price also leads to more EEMs being implemented but at the same time higher running costs. 

  • 20.
    Mahaki, Mohammadbagher
    et al.
    Shahid Bahonar University of Kerman, Kerman, Iran.
    Mattsson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Salmanzadeh, Mazyar
    Shahid Bahonar University of Kerman, Kerman, Iran.
    Hayati, Abolfazl
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Comparing objects for human movement simulation regarding its air flow disturbance at local exhaust ventilation2021In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 247, article id 111117Article in journal (Refereed)
    Abstract [en]

    The movement of people and other objects indoors may affect airflow patterns and velocities near local exhaust ventilation hoods, and consequently has influence on the hoods’ ability to remove locally emitted contaminants and on ventilation energy requirements. In this study, such disturbance effects have been studied experimentally and numerically, with the movements consisting of a human-sized plate, cylinder and detailed manikin, respectively, making back-and-forth movements near an exhaust hood. In the experimental part of the study, a 3-D sonic anemometer was used to measure air velocity in front of the hood opening. The numerical simulations used dynamic mesh to handle object movements. The numerical results were validated against the experimental ones and yielded supplementary results on the air flow field. The results show that the turbulence produced by the objects movements included marked air velocity peaks – both assisting and impeding the suction flow – in the near field of the exhaust hood. The generated turbulence, and particularly those peaks, proved substantially larger in the case of plate movement than with cylinder and manikin movement. Overall the results indicate that a moving cylinder represents human movement better than a moving plate, and thus that it’s better to use a cylinder in some test standards that now stipulate a plate as moving object. A Percentage of Negative Velocity (PNV) parameter was introduced for assessing the capture efficiency of the local exhaust system. The PNV represents the percentage of time that the air flow is directed away from the exhaust hood in an imagined point of contaminant release. The study includes test cases where the PNV values were significantly above zero, suggesting a strong effect on the capture efficiency of the exhaust hood. Human induced turbulence that cause such reverse air flows and overall impedes hood suction may be counteracted by enhanced exhaust flow rate, but then at higher energy consumption.

  • 21.
    Milić, Vlatko
    et al.
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Ekelöw, Klas
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Andersson, Maria
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Evaluation of energy renovation strategies for 12 historic building types using LCC optimization2019In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 197, p. 156-170Article in journal (Refereed)
    Abstract [en]

    The life cycle cost (LCC)optimization is a vital method when performing building energy renovation. The present paper provides an evaluation of cost-optimal energy renovation strategies for historic buildings using LCC optimization software OPERA-MILP. The evaluation is performed based on preset targets depending on LCC (LCC optimum)and energy use (decrease by 50%), where the environmental performance is also addressed. Twelve building types, which are typical of the historic building stock in Visby, Sweden, are used as the study object. The results show possible decreases of 12–38% in LCC when targeting LCC optimum. When targeting a 50% decrease in energy use, the LCC is decreased in 21 of 26 cases compared to before energy renovation. Cost-efficient EEMs on the building envelope are characterized by low renovation costs and additional insulation of building components with poor thermal properties. Furthermore, the environmental performance from the energy renovations is highly dependent on the chosen energy system boundary. 

  • 22.
    Milić, Vlatko
    et al.
    Linköping university.
    Rohdin, Patrik
    Linköping university.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköping university.
    Further development of the change-point model – Differentiating thermal power characteristics for a residential district in a cold climate2021In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 231, article id 110639Article in journal (Refereed)
    Abstract [en]

    The building and service sector accounts for nearly 40% of total energy use in Sweden. The existing, historic building stock accounts for large part of this energy use and comprises an important part of the national pursuit to increase energy efficiency. One main problem for decreasing energy use in the existing building stock is the lack of data describing thermal performance characteristics. This paper presents a novel development of the change-point model for predicting the thermal performance of buildings using selected time periods based on time-dependent variations in climate and user behavior. The predicted thermal power characteristics include total specific heat losses (Qtotal), energy use for hot water circulation (HWC) and hot tap water (HTW), and balance temperature. A residential district with 73 historic buildings in Linköping, Sweden, has been used as the study object.

    The developed model is shown to be effective and robust for describing building thermal performance. The average R2 was 0.70 for predictions of specific heat losses. The sensitivity analyses conclude that the selected time steps and months correspond to the highest R2 value. The average variation width for prediction of the balance temperature is 0.9 °C for buildings in the interquartile range based on a three-year comparison of hourly heating power supply data. Moreover, from a property owner perspective, the model is shown to be useful for identifying deviating thermal power characteristics and can easily be used to get an overview of a district.

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  • 23.
    Sayadi, Sana
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Akander, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Hayati, Abolfazl
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Analyzing the climate-driven energy demand and carbon emission for a prototype residential nZEB in central Sweden2022In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 261, article id 111960Article in journal (Refereed)
    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.

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  • 24.
    Swing Gustafsson, Moa
    et al.
    Högskolan Dalarna, Energiteknik; Mälardalen University.
    Gustafsson, Marcus
    Högskolan Dalarna, Energiteknik; KTH.
    Myhren, Jonn Are
    Högskolan Dalarna, Byggteknik.
    Dotzauer, Erik
    Mälardalen University.
    Primary energy use in buildings in a Swedish perspective2016In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 130, p. 202-209Article in journal (Refereed)
    Abstract [en]

    The building sector accounts for a large part of the energy use in Europe and is a sector where the energy efficiency needs to improve in order to reach the EU energy and climate goals. The energy efficiency goal is set in terms of primary energy even though there are different opinions on how to calculate primary energy. When determining the primary energy use in a building several assumptions are made regarding allocation and the value of different energy sources. In order to analyze the difference in primary energy when different methods are used, this study use 16 combinations of different assumptions to calculate the primary energy use for three simulated heating and ventilations systems in a building. The system with the lowest primary energy use differs depending on the method used. Comparing a system with district heating and mechanical exhaust ventilation with a system with district heating, mechanical exhaust ventilation and exhaust air heat pump, the former has a 40% higher primary energy use in one scenario while the other has a 320% higher in another scenario. This illustrates the difficulty in determining which system makes the largest contribution to fulfilling the EU energy and climate goals.

  • 25.
    Twumasi Afriyie, Ebenezer
    et al.
    Kungliga tekniska högskolan (KTH).
    Karami, Peyman
    Kungliga tekniska högskolan (KTH).
    Norberg, Peter
    Kungliga tekniska högskolan (KTH).
    Gudmundsson, Kjartan
    Kungliga tekniska högskolan (KTH).
    Textural and thermal conductivity properties of a low density mesoporous silica material2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 75, p. 210-215Article, review/survey (Refereed)
    Abstract [en]

    In this study, the pore structure, tapped density and thermal conductivity properties of a new type of nanoporous silica material have been studied. We have applied nitrogen physisorption, high resolution scanning microscopy and Transient Plane Source thermal conductivity measurements to investigate these properties. The new mesoporous silica SNP have large BET surface area, 400–439 m2 g−1 and possess high porosity in the range of 95–97%. The results further show pore diameter centred at 43 nm or 47 nm for the two materials studied. Tapped densities as low as 0.077 g/cm3 have so far been obtained and the thermal conductivity of these materials has been measured to 0.0284 and 0.0294 W (m K)−1 at room temperature and atmospheric pressure. The effects of tapped density, pore size diameter and particle morphology on thermal conductivity are discussed.

  • 26.
    Weinberger, Gottfried
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Amiri, Shahnaz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköpings universitet.
    Investigating techno-economic effects and environmental impacts of energy renovation of residential building clusters on a district heating system2021In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 251, article id 111327Article in journal (Refereed)
    Abstract [en]

    Studying energy renovation of older residential building stocks together with the surrounding district heating (DH) system is essential to fully understand implications from a reduced district heat demand and for involved actors. This study reveals the benefit of integrating the simulation and optimization tools OPERA-MILP, IDA ICE, and MODEST to investigate thoroughly the effect of energy renovation strategies on heat load supply, building and DH system-based life cycle costs (LCCs), primary energy use, and total of direct and indirect CO2 emissions. Energy renovation considered different cluster combinations of slab and tower blocks of a stock of 343 apartment buildings in two Swedish municipalities and strategies for lowest LCC and code compliance. Applied tools were thoroughly validated and verified including heat demand and load duration curves and numerical accuracy. Results with all aggregated clusters and renovation strategy for code compliance showed a reduced combined heat and power production with 35.7 GWh/a (heat) and 6.5 GWh/a (electricity), deceased primary energy use with 36.2 GWh/a and reduction of marginal CO2 emissions with 8.4 kton/a mainly from released biofuels substituting for fossil fuels in power plants, increased CO2 emissions of 0.5 kton/a with electricity production mix, and financial deficit for building owners, energy companies, and industries of respective 44, 33.9, and 2.2 M€/50a.

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  • 27.
    Weinberger, Gottfried
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Techno-economic investigation of the potential for energy efficiency measures of multi-story apartment buildings at cluster level using different district heating tariffs2021In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 236, article id 110758Article in journal (Refereed)
    Abstract [en]

    The paper presents a systematic approach to study energy renovation of a larger building stock at cluster level using categorization, classification into modules, life cycle cost (LCC) optimization, and bottom-up modeling. Seven-story clusters of slab and tower blocks were analyzed to investigate the techno-economic potential for energy efficiency measures (EEMs) of 401 multi-story apartment buildings constructed during the 1960s and ’70s located in two Swedish municipalities. Energy renovation with intention of lowest LCC and projected energy savings concerned the purchased energy for space heating and domestic hot water use allocated by different district heating (DH) tariffs. Different conditions for DH and performance indicators demonstrated code compliance. The LCC analysis revealed a rather small potential for cost-optimal EEMs on building envelopes. Incentives to gain LCC savings during energy renovation increased with a DH tariff with constant price rate throughout the year. A starting point for cost-effective energy renovations arguably would be clusters with 94 two-story and 160 three-story slab blocks, also requiring fewer EEMs to achieve thermal performance requirements. DH systems using industrial excess heat can improve buildings’ energy performance and reduce required EEM investment costs. The DH price level is shown to be a vital issue for cost-effective energy renovations.

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  • 28.
    Yang, Bin
    et al.
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Melikov, A.K.
    International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Denmark.
    Kabanshi, Alan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Zhang, C.
    Department of Civil Engineering, Aalborg University, Aalborg, Denmark.
    Bauman, F. S.
    Center for the Built Environment, University of California, Berkeley, CA, United States.
    Cao, G.
    Department of Energy and Process, Norwegian University of Science and Technology, KolbjørnHejesVei 1B, Trondheim, Norway.
    Awbi, H.
    School of Construction Management and Engineering, University of Reading, United Kingdom.
    Wigö, Hans
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Niu, J.
    School of Architecture, Design and Planning, The University of Sydney, Australia.
    Cheong, K. W. D.
    Department of Building, School of Design and Environment, National University of Singapore, Singapore.
    Tham, K. W.
    Department of Building, School of Design and Environment, National University of Singapore, Singapore.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Nielsen, P. V.
    Department of Civil Engineering, Aalborg University, Aalborg, Denmark.
    Kosonen, R.
    Department of Mechanical Engineering, School of Engineering, Aalto University, Espoo, Finland; College of Urban Construction, Nanjing Tech University, Nanjing, China.
    Yao, R.
    School of Construction Management and Engineering, University of Reading, United Kingdom.
    Kato, S.
    Institute of Industrial Science, The University of Tokyo, Tokyo, Japan.
    Sekhar, S. C.
    Department of Building, School of Design and Environment, National University of Singapore, Singapore.
    Schiavon, Stefano
    Center for the Built Environment, University of California, Berkeley, CA, United States.
    Karimipanah, Taghi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Li, X.
    Department of Building Science, School of Architecture, Tsinghua University, Beijing, China.
    Lin, Z.
    Division of Building Science and Technology, City University of Hong Kong, Hong Kong, Hong Kong.
    A review of advanced air distribution methods - theory, practice, limitations and solutions2019In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 202, article id 109359Article in journal (Refereed)
    Abstract [en]

    Ventilation and air distribution methods are important for indoor thermal environments and air quality. Effective distribution of airflow for indoor built environments with the aim of simultaneously offsetting thermal and ventilation loads in an energy efficient manner has been the research focus in the past several decades. Based on airflow characteristics, ventilation methods can be categorized as fully mixed or non-uniform. Non-uniform methods can be further divided into piston, stratified and task zone ventilation. In this paper, the theory, performance, practical applications, limitations and solutions pertaining to ventilation and air distribution methods are critically reviewed. Since many ventilation methods are buoyancy driving that confines their use for heating mode, some methods suitable for heating are discussed. Furthermore, measuring and evaluating methods for ventilation and air distribution are also discussed to give a comprehensive framework of the review.

  • 29.
    Zhang, Chen
    et al.
    Department of the Built Environment, Aalborg University, Denmark.
    Berk Kazanci, Ongun
    International Centre for Indoor Environment and Energy - ICIEE, Department of Civil Engineering, Technical University of Denmark, Denmark.
    Levinson, Ronnen
    Building Technology and Urban Systems Division, Lawrence Berkeley National Laboratory, USA.
    Heiselberg, Per
    Department of the Built Environment, Aalborg University, Denmark.
    Olesen, Bjarne W.
    International Centre for Indoor Environment and Energy - ICIEE, Department of Civil Engineering, Technical University of Denmark, Denmark.
    Chiesa, Giacomo
    Department of Architecture and Design, Politecnico di Torino, Italy.
    Sodagar, Behzad
    School of Architecture and the Built Environment, University of Lincoln, UK.
    Ai, Zhengtao
    Department of Building Environment and Energy, Hunan University, China.
    Selkowitz, Stephen
    Building Technology and Urban Systems Division, Lawrence Berkeley National Laboratory, USA.
    Zinzi, Michele
    ENEA Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Italy.
    Mahdavi, Ardeshir
    Department of Building Physics and Building Ecology, TU Wien, Austria.
    Akander, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Hayati, Abolfazl
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Sayadi, Sana
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Forghani, Sadegh
    Zhang, Hui
    Center for the Built Environment, University of California, Berkeley, CA, USA.
    Arens, Edward
    Center for the Built Environment, University of California, Berkeley, CA, USA.
    Zhang, Guoqiang
    School of Civil, Environmental and Architectural Engineering, Korea University, Republic of Korea.
    Resilient cooling strategies – A critical review and qualitative assessment2021In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 251, article id 111312Article in journal (Refereed)
    Abstract [en]

    The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out.

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