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  • 1.
    Joudi, Ali
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering. Energy and Environmental Technology, Dalarna University, Falun, Sweden.
    Cehlin, Mathias
    Building, Energy & Environmental Engineering, University of Gävle, Gävle, Sweden.
    Svedung, Harald
    SSAB Europe, Borlänge, Sweden.
    Rohdin, Patrik
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Moshfegh, Bahram
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Influence of reflective interior surfaces on indoor thermal environment and energy use using a coupling model for energy simulation and CFD2015Manuscript (preprint) (Other academic)
    Abstract [en]

    The importance of reducing the building energy use and maintaining the desired indoor climate has long inspired creative solution such as optimized optical properties for building surfaces. This paper aims to address the influence of interior thermal reflective surfaces on both indoor thermal environments with high spatial resolution and energy use. To do so, this work employs a coupling method using building energy simulation (BES) and computational fluid dynamics (CFD). The results indicate increase in the mean radiation temperature (MRT) and reduction in the floor heating energy use by the use of interior reflective surfaces. The study yields analysis of operative temperatures and interior surface heat fluxes. Overall, the interior reflective surfaces can contribute to improved building thermal performance and energy saving.

  • 2.
    Joudi, Ali
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering. Energy Technology, Dalarna University, Falun, Sweden; SSAB Europe, Borlänge, Sweden.
    Cehlin, Mathias
    Building, Energy & Environmental Engineering, University of Gävle, Gävle, Sweden .
    Svedung, Harald
    Energy Technology, Dalarna University, Falun, Sweden; SSAB Europe, Borlänge, Sweden.
    Rönnelid, Mats
    Energy Technology, Dalarna University, Falun, Sweden .
    Moshfegh, Bahram
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering. Building, Energy & Environmental Engineering, University of Gävle, Gävle, Sweden .
    Numerical and experimental investigation of the influence of infrared reflective interior surfaces on building temperature distributions2017In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 26, no 3, p. 355-367Article in journal (Refereed)
    Abstract [en]

    Radiative properties of interior surfaces can affect not only the building heat flux but also the indoor environment, the latter of which has not been thoroughly investigated. The aim of this study is to analyse the effect of surface emissivity on indoor air and surface temperature distributions in a test cabin with reflective interior surfaces. This was done by comparing experimental and simulation data of the test cabin with that of a normal cabin. This study employs transient computational fluid dynamics (CFD) using re-normalisation group (RNG) kε model, surface-to-surface radiation model and an enhanced wall function. Boundary conditions were assigned to exterior surfaces under variable outdoor conditions. The numerical and the measurement results indicate that using interior reflective surfaces will affect the indoor air temperature distribution by increasing the vertical temperature gradient depending on the time of the day. CFD simulations with high spatial resolution results show increased interior surface temperature gradients consistent with the increased vertical air temperature gradient. The influence of reflective surfaces is potentially greater with higher indoor surface temperature asymmetry. The vertical indoor air temperature gradient and surface temperatures are important parameters for indoor thermal comfort.

  • 3.
    Joudi, Ali
    et al.
    School of Technology and Business Studies, SERC, Dalarna University, Sweden.
    Rönnelid, Mats
    School of Technology and Business Studies, SERC, Dalarna University, Sweden.
    Svedung, Harald
    School of Technology and Business Studies, SERC, Dalarna University, Sweden.
    Wäckelgård, Ewa
    School of Technology and Business Studies, SERC, Dalarna University, Sweden.
    Energy Efficient Buildings with Functional Steel Cladding2011In: World Renewable Energy Congress, Linköping: Linköping University Electronic Press, 2011, Vol. 8, p. 2004-2009Conference paper (Refereed)
    Abstract [en]

    The aim of the study is to develop a model for the energy balance of buildings that includes the effect from the radiation properties of interior and exterior surfaces of the building envelope. As a first step we have used ice arenas as case study objects to investigate the importance of interior low emissivity surfaces. Measurements have been done in two ice arenas in the north part of Sweden, one with lower and one with higher ceiling emissivity. The results show that the low emissivity ceiling gives a much lower radiation temperature interacting with the ice under similar conditions. The dynamic modelling of the roof in ice arenas shows a similar dependence of the roof-to-ice heat flux and the ceiling emissivity. A second part of the study focus on how to realise paints with very low thermal emissivity to be used on interior building surfaces.

  • 4.
    Joudi, Ali
    et al.
    Högskolan Dalarna, Energi och miljöteknik.
    Svedung, Harald
    Högskolan Dalarna, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Energi och miljöteknik.
    Rönnelid, Mats
    Högskolan Dalarna, Energi och miljöteknik.
    Highly reflective coatings for interior and exterior steel cladding and the energy efficiency of buildings2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 12, p. 4655-4666Article in journal (Refereed)
    Abstract [en]

    The effect of surface heat-radiation properties of coil-coated steel cladding material on the energy efficiency of buildings in Nordic climate is addressed by parallel temperature and energy usage measurements in a series of test cabins with different exterior solar reflectivity and interior thermal reflectivity. During one year, a number of one- or two-week experiments with air conditioner cooling and electrical floor heating were made while logging air-, radiation- and surface temperatures, energy consumption and weather conditions. Measurements show significant energy savings in the test cabins by the use of high thermal reflectivity interior surfaces both during heating and cooling and a strongly reduced cooling demand by the use of high solar reflectivity exterior surfaces. Results are interpreted within the context of a steady-state energy flux model, to illuminate the importance of surface resistance properties (radiation and convective heat dissipation).

  • 5.
    Joudi, Ali
    et al.
    Energy and Environmental Technology, Dalarna University, Falun, Sweden.
    Svedung, Harald
    SSAB Europe, Borlänge, Sweden.
    Cehlin, Mathias
    Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik.
    Rönnelid, Mats
    Energy and Environmental Technology, Dalarna University, Falun, Sweden .
    Reflective coatings for interior and exterior of buildings and improving thermal performance2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 103, p. 562-570Article in journal (Refereed)
    Abstract [en]

    The importance of reducing building energy usage and thriving for more energy efficient architectures, has nurtured creative solutions and smart choices of materials in the last few decades. Among those are optimizing surface optical properties for both interior and exterior claddings of the building. Development in the coil-coating steel industries has now made it possible to allocate correct optical properties for steel clad buildings with improved thermal performance. Although the importance of the exterior coating and solar gain are thoroughly studied in many literatures, the effect of interior cladding are less tackled, especially when considering a combination of both interior and exterior reflective coatings. This paper contemplates the thermal behavior of small cabins with reflective coatings on both interior and exterior cladding, under different conditions and climates with the aim to clarify and point out to the potential energy saving by smart choices of clad coatings.

  • 6.
    Joudi, Ali
    et al.
    Energy and Environmental Technology, Dalarna University, Falun, Sweden.
    Svedung, Harald
    SSAB EMEA, SE-78184 Borlänge, Sweden.
    Rönnelid, Mats
    Energy and Environmental Technology, Dalarna University, Falun, Sweden.
    Energy efficient surfaces on building sandwich panels - A dynamic simulation model2011In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 43, no 9, p. 2462-2467Article in journal (Refereed)
    Abstract [en]

    The choice of building envelope is critical for the energy performance of buildings. The major part of the energy used by a building during its lifetime is used for maintaining a suitable interior thermal climate under varying exterior conditions. Although exterior heat radiation properties (i.e. total solar reflectivity and long wave thermal emissivity) have been well accepted to have a large impact on the need for active cooling in warmer climate, the effect of a reduced thermal emissivity on interior surfaces on the building thermal energy flux is rarely studied. This paper addresses the sensitivity of the thermal energy flux through a sandwich panel, by systematically varying the surface thermal emissivity (both interior and exterior) and total solar reflectance of exterior surface, for three geographical locations: southern, middle and northern Europe. A model is introduced for calculating the effect of both interior and exterior optical properties of a horizontal roof panel in terms of net energy flux per unit area. The results indicate potential energy saving by the smart choice of optical properties of interior and exterior surfaces.

  • 7.
    Joudi, Mohammad Ali
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Radiation properties of coil-coated steel in building envelope surfaces and the influence on building thermal performance2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Recent studies have shown that the optical properties of building exterior surfaces are important in terms of energy use and thermal comfort. While the majority of the studies are related to exterior surfaces, the radiation properties of interior surfaces are less thoroughly investigated. Development in the coil-coating industries has now made it possible to allocate different optical properties for both exterior and interior surfaces of steel-clad buildings. The aim of this thesis is to investigate the influence of surface radiation properties with the focus on the thermal emittance of the interior surfaces, the modeling approaches and their consequences in the context of the building energy performance and indoor thermal environment.

    The study consists of both numerical and experimental investigations. The experimental investigations include parallel field measurements on three similar test cabins with different interior and exterior surface radiation properties in Borlänge, Sweden, and two ice rink arenas with normal and low emissive ceiling in Luleå, Sweden. The numerical methods include comparative simulations by the use of dynamic heat flux models, Building Energy Simulation (BES), Computational Fluid Dynamics (CFD) and a coupled model for BES and CFD. Several parametric studies and thermal performance analyses were carried out in combination with the different numerical methods.

    The parallel field measurements on the test cabins include the air, surface and radiation temperatures and energy use during passive and active (heating and cooling) measurements. Both measurement and comparative simulation results indicate an improvement in the indoor thermal environment when the interior surfaces have low emittance. In the ice rink arenas, surface and radiation temperature measurements indicate a considerable reduction in the ceiling-to-ice radiation by the use of low emittance surfaces, in agreement with a ceiling-toice radiation model using schematic dynamic heat flux calculations.

    The measurements in the test cabins indicate that the use of low emittance surfaces can increase the vertical indoor air temperature gradients depending on the time of day and outdoor conditions. This is in agreement with the transient CFD simulations having the boundary condition assigned on the exterior surfaces. The sensitivity analyses have been performed under different outdoor conditions and surface thermal radiation properties. The spatially resolved simulations indicate an increase in the air and surface temperature gradients by the use of low emittance coatings. This can allow for lower air temperature at the occupied zone during the summer.

    The combined effect of interior and exterior reflective coatings in terms of energy use has been investigated by the use of building energy simulation for different climates and internal heat loads. The results indicate possible energy savings by the smart choice of optical properties on interior and exterior surfaces of the building.

    Overall, it is concluded that the interior reflective coatings can contribute to building energy savings and improvement of the indoor thermal environment. This can be numerically investigated by the choice of appropriate models with respect to the level of detail and computational load. This thesis includes comparative simulations at different levels of detail.

    List of papers
    1. Highly reflective coatings for interior and exterior steel cladding and the energy efficiency of buildings
    Open this publication in new window or tab >>Highly reflective coatings for interior and exterior steel cladding and the energy efficiency of buildings
    2011 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 12, p. 4655-4666Article in journal (Refereed) Published
    Abstract [en]

    The effect of surface heat-radiation properties of coil-coated steel cladding material on the energy efficiency of buildings in Nordic climate is addressed by parallel temperature and energy usage measurements in a series of test cabins with different exterior solar reflectivity and interior thermal reflectivity. During one year, a number of one- or two-week experiments with air conditioner cooling and electrical floor heating were made while logging air-, radiation- and surface temperatures, energy consumption and weather conditions. Measurements show significant energy savings in the test cabins by the use of high thermal reflectivity interior surfaces both during heating and cooling and a strongly reduced cooling demand by the use of high solar reflectivity exterior surfaces. Results are interpreted within the context of a steady-state energy flux model, to illuminate the importance of surface resistance properties (radiation and convective heat dissipation).

    Place, publisher, year, edition, pages
    Elsevier, 2011
    Keywords
    Total solar reflectivity, Reflective coating, Thermal emissivity, Building interior heat flux, Energy efficient buildings Energy saving
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-118285 (URN)10.1016/j.apenergy.2011.06.002 (DOI)000295387200041 ()
    Available from: 2011-09-01 Created: 2015-05-25 Last updated: 2017-12-04Bibliographically approved
    2. Energy efficient surfaces on building sandwich panels - A dynamic simulation model
    Open this publication in new window or tab >>Energy efficient surfaces on building sandwich panels - A dynamic simulation model
    2011 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 43, no 9, p. 2462-2467Article in journal (Refereed) Published
    Abstract [en]

    The choice of building envelope is critical for the energy performance of buildings. The major part of the energy used by a building during its lifetime is used for maintaining a suitable interior thermal climate under varying exterior conditions. Although exterior heat radiation properties (i.e. total solar reflectivity and long wave thermal emissivity) have been well accepted to have a large impact on the need for active cooling in warmer climate, the effect of a reduced thermal emissivity on interior surfaces on the building thermal energy flux is rarely studied. This paper addresses the sensitivity of the thermal energy flux through a sandwich panel, by systematically varying the surface thermal emissivity (both interior and exterior) and total solar reflectance of exterior surface, for three geographical locations: southern, middle and northern Europe. A model is introduced for calculating the effect of both interior and exterior optical properties of a horizontal roof panel in terms of net energy flux per unit area. The results indicate potential energy saving by the smart choice of optical properties of interior and exterior surfaces.

    Keywords
    Total solar reflectivity, Reflective coating, Thermal emissivity, Building heat flux, Energy efficiency
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-118286 (URN)10.1016/j.enbuild.2011.05.026 (DOI)000294834900048 ()
    Available from: 2011-09-01 Created: 2015-05-25 Last updated: 2017-12-04Bibliographically approved
    3. Energy Efficient Buildings with Functional Steel Cladding
    Open this publication in new window or tab >>Energy Efficient Buildings with Functional Steel Cladding
    2011 (English)In: World Renewable Energy Congress, Linköping: Linköping University Electronic Press, 2011, Vol. 8, p. 2004-2009Conference paper, Published paper (Refereed)
    Abstract [en]

    The aim of the study is to develop a model for the energy balance of buildings that includes the effect from the radiation properties of interior and exterior surfaces of the building envelope. As a first step we have used ice arenas as case study objects to investigate the importance of interior low emissivity surfaces. Measurements have been done in two ice arenas in the north part of Sweden, one with lower and one with higher ceiling emissivity. The results show that the low emissivity ceiling gives a much lower radiation temperature interacting with the ice under similar conditions. The dynamic modelling of the roof in ice arenas shows a similar dependence of the roof-to-ice heat flux and the ceiling emissivity. A second part of the study focus on how to realise paints with very low thermal emissivity to be used on interior building surfaces.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2011
    Series
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 57
    Keywords
    energy balance, low emissivity, radiation properties
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-118287 (URN)10.3384/ecp110572004 (DOI)978-91-7393-070-3 (ISBN)
    Conference
    World Renewable Energy Congress – Sweden; 8–13 May, 2011, Linköping, Sweden
    Available from: 2015-05-25 Created: 2015-05-25 Last updated: 2018-01-29Bibliographically approved
    4. Reflective coatings for interior and exterior of buildings and improving thermal performance
    Open this publication in new window or tab >>Reflective coatings for interior and exterior of buildings and improving thermal performance
    2013 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 103, p. 562-570Article in journal (Refereed) Published
    Abstract [en]

    The importance of reducing building energy usage and thriving for more energy efficient architectures, has nurtured creative solutions and smart choices of materials in the last few decades. Among those are optimizing surface optical properties for both interior and exterior claddings of the building. Development in the coil-coating steel industries has now made it possible to allocate correct optical properties for steel clad buildings with improved thermal performance. Although the importance of the exterior coating and solar gain are thoroughly studied in many literatures, the effect of interior cladding are less tackled, especially when considering a combination of both interior and exterior reflective coatings. This paper contemplates the thermal behavior of small cabins with reflective coatings on both interior and exterior cladding, under different conditions and climates with the aim to clarify and point out to the potential energy saving by smart choices of clad coatings.

    Place, publisher, year, edition, pages
    Oxford: Elsevier, 2013
    Keywords
    Reflective coatings, Low energy building, Energy simulation, Total solar reflectance, Interior thermal emittance
    National Category
    Energy Systems Building Technologies
    Identifiers
    urn:nbn:se:liu:diva-118288 (URN)10.1016/j.apenergy.2012.10.019 (DOI)000314669500053 ()2-s2.0-84871715773 (Scopus ID)
    Available from: 2014-11-09 Created: 2015-05-25 Last updated: 2017-12-04Bibliographically approved
    5. Numerical and experimental investigation of the influence of infrared reflective interior surfaces on building temperature distributions
    Open this publication in new window or tab >>Numerical and experimental investigation of the influence of infrared reflective interior surfaces on building temperature distributions
    Show others...
    2017 (English)In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 26, no 3, p. 355-367Article in journal (Refereed) Published
    Abstract [en]

    Radiative properties of interior surfaces can affect not only the building heat flux but also the indoor environment, the latter of which has not been thoroughly investigated. The aim of this study is to analyse the effect of surface emissivity on indoor air and surface temperature distributions in a test cabin with reflective interior surfaces. This was done by comparing experimental and simulation data of the test cabin with that of a normal cabin. This study employs transient computational fluid dynamics (CFD) using re-normalisation group (RNG) kε model, surface-to-surface radiation model and an enhanced wall function. Boundary conditions were assigned to exterior surfaces under variable outdoor conditions. The numerical and the measurement results indicate that using interior reflective surfaces will affect the indoor air temperature distribution by increasing the vertical temperature gradient depending on the time of the day. CFD simulations with high spatial resolution results show increased interior surface temperature gradients consistent with the increased vertical air temperature gradient. The influence of reflective surfaces is potentially greater with higher indoor surface temperature asymmetry. The vertical indoor air temperature gradient and surface temperatures are important parameters for indoor thermal comfort.

    Place, publisher, year, edition, pages
    Sage Publications, 2017
    Keywords
    Reflective interior surfaces, indoor air temperature gradient, Transient computational fluid dynamics, surface-to-surface radiation, building thermal performance
    National Category
    Energy Systems Building Technologies
    Identifiers
    urn:nbn:se:liu:diva-118289 (URN)10.1177/1420326X15609966 (DOI)000399487300007 ()
    Note

    Funding agencies|SSAB Europe; Dalarna University; University of Gävle; Linköping University.

    At the time for thesis presentation publication was in status: Manuscript

    Available from: 2015-05-25 Created: 2015-05-25 Last updated: 2017-05-05Bibliographically approved
    6. Influence of reflective interior surfaces on indoor thermal environment and energy use using a coupling model for energy simulation and CFD
    Open this publication in new window or tab >>Influence of reflective interior surfaces on indoor thermal environment and energy use using a coupling model for energy simulation and CFD
    Show others...
    2015 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The importance of reducing the building energy use and maintaining the desired indoor climate has long inspired creative solution such as optimized optical properties for building surfaces. This paper aims to address the influence of interior thermal reflective surfaces on both indoor thermal environments with high spatial resolution and energy use. To do so, this work employs a coupling method using building energy simulation (BES) and computational fluid dynamics (CFD). The results indicate increase in the mean radiation temperature (MRT) and reduction in the floor heating energy use by the use of interior reflective surfaces. The study yields analysis of operative temperatures and interior surface heat fluxes. Overall, the interior reflective surfaces can contribute to improved building thermal performance and energy saving.

    Keywords
    Thermal reflective surfaces, mean radiation temperature, building thermal performance, coupling building energy simulation and CFD
    National Category
    Energy Systems Building Technologies
    Identifiers
    urn:nbn:se:liu:diva-118290 (URN)
    Available from: 2015-05-25 Created: 2015-05-25 Last updated: 2015-05-26Bibliographically approved
1 - 7 of 7
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