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Atmosferik Sınır Tabakası Stabilitesinin Bina Yüzey Sıcaklığı Üzerindeki Etkisi

Year 2020, Ejosat Special Issue 2020 (ISMSIT), 264 - 269, 30.11.2020
https://doi.org/10.31590/ejosat.821743

Abstract

Net sıfır enerjili binalar, insanlığın enerji tüketimini azaltmaya yönelik en önemli adımlardan biridir. Binalarda, önemli miktarda enerji ısıtma ve soğutma amacıyla kullanılmaktadır. Binalarda atmosfer ile ısı transferi yüzeyleri vasıtasıyla gerçekleşmektedir. Bina yüzeyinin dışı ve içerisi arasındaki fark duvarlardan iletilecek ısı miktarını belirlemektedir. Bina dış yüzeyinin sıcaklığı rüzgar, güneş radyasyonu, dış sıcaklık ve Atmosferik Sınır Tabakası (AST) stabilite özellikleri gibi çevresel koşullara göre değişebilir. HAD simülasyonları yardımıyla, bina yüzeyi sıcaklık değişimi bir ısı haritası olarak oluşturulabilir. Oluşturulan ısı haritası, enerji verimli binaların tasarlanmasına yardımcı olabilir.
Bu çalışmada, genel bir binanın cephe sıcaklık haritası ANSYS Fluent ile simüle edilmiştir. AST’nin tabakalaşması türbülans özelliklerini ve dikey profildeki sıcaklığı değiştirdiğinden, simülasyonlar sırasında tabakalaşmaya özel önem verilmektedir. Monin-Obukhov (M-O) uzunluğuna göre farklı tabakalaşma seviyeleri belirlenir. Simülasyonlar için RANS denklemleri çözülmüş ve türbülans modellemesi için realizable k-ε modeli kullanılmıştır. Simülasyon için giriş, çıkış ve alt kısımdaki sınır koşulları M-O benzerliği doğrultusunda verilmiştir. Tam boyutlarıyla modellenen binaya literatürden alınan ısı akışı değerleri verilmiştir. Üç farklı rüzgar hızı ve üç farklı tabakalaşma durumu analiz edilerek sonuç olarak 9 senaryo oluşturulmuştur. Oluşturulan senaryoların hepsinde yer seviyesi sıcaklık 27 derece olarak alınmış ve binaların ürettiği ısı akışı 105 w/m2 olarak literatürden alınmıştır. 9 senaryonun sonucu karşılaştırıldığında, tabakalaşmanın binanın cephe sıcaklığı üzerindeki etkisi gözlemlenmiştir. Rüzgar hızı arttıkça, tabakalaşmanın cephe sıcaklığı üzerindeki etkisi artmaktadır.

References

  • Allegrini, J., Dorer, V., & Carmeliet, J. (2014). Buoyant flows in street canyons: Validation of CFD simulations with wind tunnel measurements. Building and Environment, 72, 63–74. https://doi.org/10.1016/j.buildenv.2013.10.021
  • Allegrini, J., Dorer, V., & Carmeliet, J. (2014). Buoyant flows in street canyons: Validation of CFD simulations with wind tunnel measurements. Building and Environment, 72, 63–74. https://doi.org/10.1016/j.buildenv.2013.10.021
  • Allegrini, J., Dorer, V., & Carmeliet, J. (2015). Coupled CFD, radiation and building energy model for studying heat fluxes in an urban environment with generic building configurations. Sustainable Cities and Society, 19, 385–394. https://doi.org/10.1016/j.scs.2015.07.009
  • Allen, L., Lindberg, F., & Grimmond, C. S. B. (2011). Global to city scale urban anthropogenic heat flux: Model and variability. International Journal of Climatology, 31(13), 1990–2005. https://doi.org/10.1002/joc.2210
  • Bartak, M., Beausoleil-Morrison, I., Clarke, J. A., Denev, J., Drkal, F., Lain, M., … Stankov, P. (2002). Integrating CFD and building simulation. Building and Environment, 37(8–9), 865–871. https://doi.org/10.1016/S0360-1323(02)00045-8
  • Hosseini, M., Tardy, F., & Lee, B. (2018). Cooling and heating energy performance of a building with a variety of roof designs; the effects of future weather data in a cold climate. Journal of Building Engineering, 17(February), 107–114. https://doi.org/10.1016/j.jobe.2018.02.001
  • Mahrt, L. (1998). Stratified Atmospheric Boundary Layers and Breakdown of Models. Theoretical and Computational Fluid Dynamics, 11(3–4), 263–279. https://doi.org/10.1007/s001620050093
  • Mahrt, L. (1999). Stratified atmospheric boundary layers. Boundary-Layer Meteorology, 90(3), 375–396. https://doi.org/10.1023/A:1001765727956
  • Miralles, D. G., Teuling, A. J., Van Heerwaarden, C. C., & De Arellano, J. V. G. (2014). Mega-heatwave temperatures due to combined soil desiccation and atmospheric heat accumulation. Nature Geoscience, 7(5), 345–349. https://doi.org/10.1038/ngeo2141
  • Monin, A. S., & Obukhov, A. M. (1954). Basic laws of turbulent mixing in the surface layer of the atmosphere. Contrib. Geophys. Inst. Acad. Sci. USSR, 24(151), 163–187.
  • Oke, T. R. (1973). City size and the urban heat island. Atmospheric Environment Pergamon Pres, 7, 769–779. https://doi.org/10.1016/0004-6981(73)90140-6
  • Önal, S. (2014). Yapıların Enerji Kimlik Belgeleri Üzerine Değerlendirmeler Evaluation on Energy Identity Documents of The Buildings. European Journal of Science and Technology, 1(3), 100–105.
  • Panofsky, H. A., & Dutton, J. A. (1984). Hans A Panofsky_ John A Dutton -Atmospheric turbulence _ models and methods for engineering applications-Wiley (1984).pdf. Newyork: Wiley - interscience.
  • Sartori, I., Napolitano, A., & Voss, K. (2012). Net zero energy buildings: A consistent definition framework. Energy and Buildings, 48, 220–232. https://doi.org/10.1016/j.enbuild.2012.01.032
  • Xie, X., Liu, C. H., Leung, D. Y. C., & Leung, M. K. H. (2006). Characteristics of air exchange in a street canyon with ground heating. Atmospheric Environment, 40(33), 6396–6409. https://doi.org/10.1016/j.atmosenv.2006.05.050

The Effect of Atmospheric Boundary Layer Stratification on the Facade Temperature

Year 2020, Ejosat Special Issue 2020 (ISMSIT), 264 - 269, 30.11.2020
https://doi.org/10.31590/ejosat.821743

Abstract

The net-zero energy buildings are one of the most important steps towards decreasing the total energy consumption of humanity. In the buildings, a considerable amount of energy is used for heating and cooling purposes, and heat is transferred to the atmosphere via the façade of the buildings. The difference between the inside and outside temperature of the facade determine the heat flux through the walls. The temperature of the façade can vary with environmental conditions such as wind, solar radiation, outside temperature, and stability characteristics of the Atmospheric Boundary Layer (ABL). With the aid of CFD simulations, the temperature variation can be created as a heat map. The created heat map can help to design energy-efficient buildings.
In this study, the façade temperature map of a generic building is simulated with ANSYS Fluent. Since the stratification changes the turbulence characteristics and temperature along with the vertical profile of ABL, special care is given to the stratification during the simulations. Different stratification levels are determined in line with the Monin-Obukhov (M-O) length. For the simulations, RANS equations are solved and the realizable k-ε model is used for the turbulence modeling. The boundary conditions at the inlet, outlet, and bottom are given in line with the M-O length. The building is explicitly modeled and heat flux values taken from the literature. Three different wind speed and three different stratification conditions are analyzed and as a result, 9 scenarios are created. The result of the 9 scenarios shows the effect of stratification on the facade temperature of the building. As the wind speed increases the effect of stratification on the facade temperature increases.

References

  • Allegrini, J., Dorer, V., & Carmeliet, J. (2014). Buoyant flows in street canyons: Validation of CFD simulations with wind tunnel measurements. Building and Environment, 72, 63–74. https://doi.org/10.1016/j.buildenv.2013.10.021
  • Allegrini, J., Dorer, V., & Carmeliet, J. (2014). Buoyant flows in street canyons: Validation of CFD simulations with wind tunnel measurements. Building and Environment, 72, 63–74. https://doi.org/10.1016/j.buildenv.2013.10.021
  • Allegrini, J., Dorer, V., & Carmeliet, J. (2015). Coupled CFD, radiation and building energy model for studying heat fluxes in an urban environment with generic building configurations. Sustainable Cities and Society, 19, 385–394. https://doi.org/10.1016/j.scs.2015.07.009
  • Allen, L., Lindberg, F., & Grimmond, C. S. B. (2011). Global to city scale urban anthropogenic heat flux: Model and variability. International Journal of Climatology, 31(13), 1990–2005. https://doi.org/10.1002/joc.2210
  • Bartak, M., Beausoleil-Morrison, I., Clarke, J. A., Denev, J., Drkal, F., Lain, M., … Stankov, P. (2002). Integrating CFD and building simulation. Building and Environment, 37(8–9), 865–871. https://doi.org/10.1016/S0360-1323(02)00045-8
  • Hosseini, M., Tardy, F., & Lee, B. (2018). Cooling and heating energy performance of a building with a variety of roof designs; the effects of future weather data in a cold climate. Journal of Building Engineering, 17(February), 107–114. https://doi.org/10.1016/j.jobe.2018.02.001
  • Mahrt, L. (1998). Stratified Atmospheric Boundary Layers and Breakdown of Models. Theoretical and Computational Fluid Dynamics, 11(3–4), 263–279. https://doi.org/10.1007/s001620050093
  • Mahrt, L. (1999). Stratified atmospheric boundary layers. Boundary-Layer Meteorology, 90(3), 375–396. https://doi.org/10.1023/A:1001765727956
  • Miralles, D. G., Teuling, A. J., Van Heerwaarden, C. C., & De Arellano, J. V. G. (2014). Mega-heatwave temperatures due to combined soil desiccation and atmospheric heat accumulation. Nature Geoscience, 7(5), 345–349. https://doi.org/10.1038/ngeo2141
  • Monin, A. S., & Obukhov, A. M. (1954). Basic laws of turbulent mixing in the surface layer of the atmosphere. Contrib. Geophys. Inst. Acad. Sci. USSR, 24(151), 163–187.
  • Oke, T. R. (1973). City size and the urban heat island. Atmospheric Environment Pergamon Pres, 7, 769–779. https://doi.org/10.1016/0004-6981(73)90140-6
  • Önal, S. (2014). Yapıların Enerji Kimlik Belgeleri Üzerine Değerlendirmeler Evaluation on Energy Identity Documents of The Buildings. European Journal of Science and Technology, 1(3), 100–105.
  • Panofsky, H. A., & Dutton, J. A. (1984). Hans A Panofsky_ John A Dutton -Atmospheric turbulence _ models and methods for engineering applications-Wiley (1984).pdf. Newyork: Wiley - interscience.
  • Sartori, I., Napolitano, A., & Voss, K. (2012). Net zero energy buildings: A consistent definition framework. Energy and Buildings, 48, 220–232. https://doi.org/10.1016/j.enbuild.2012.01.032
  • Xie, X., Liu, C. H., Leung, D. Y. C., & Leung, M. K. H. (2006). Characteristics of air exchange in a street canyon with ground heating. Atmospheric Environment, 40(33), 6396–6409. https://doi.org/10.1016/j.atmosenv.2006.05.050
There are 15 citations in total.

Details

Primary Language Turkish
Subjects Engineering
Journal Section Articles
Authors

Yiğit Altan 0000-0003-0208-6867

Publication Date November 30, 2020
Published in Issue Year 2020 Ejosat Special Issue 2020 (ISMSIT)

Cite

APA Altan, Y. (2020). Atmosferik Sınır Tabakası Stabilitesinin Bina Yüzey Sıcaklığı Üzerindeki Etkisi. Avrupa Bilim Ve Teknoloji Dergisi264-269. https://doi.org/10.31590/ejosat.821743