Utilizing Computational Fluid Dynamics in the Analysis of Natural Ventilation in Buildings

Authors: A. W. J. Wong, I. H. Ibrahim

Abstract:

Increasing urbanisation has driven building designers to incorporate natural ventilation in the designs of sustainable buildings. This project utilises Computational Fluid Dynamics (CFD) to investigate the natural ventilation of an academic building, SIT@SP, using an assessment criterion based on daily mean temperature and mean velocity. The areas of interest are the pedestrian level of first and fourth levels of the building. A reference case recommended by the Architectural Institute of Japan was used to validate the simulation model. The validated simulation model was then used for coupled simulations on SIT@SP and neighbouring geometries, under two wind speeds. Both steady and transient simulations were used to identify differences in results. Steady and transient results are agreeable with the transient simulation identifying peak velocities during flow development. Under a lower wind speed, the first level was sufficiently ventilated while the fourth level was not. The first level has excessive wind velocities in the higher wind speed and the fourth level was adequately ventilated. Fourth level flow velocity was consistently lower than those of the first level. This is attributed to either simulation model error or poor building design. SIT@SP is concluded to have a sufficiently ventilated first level and insufficiently ventilated fourth level. Future works for this project extend to modifying the urban geometry, simulation model improvements, evaluation using other assessment metrics and extending the area of interest to the entire building.

Keywords: Buildings, CFD simulation, natural ventilation, urban airflow.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1126339

References:

[1] J.F. Nicol and M. A. Humphreys, “Adaptive Thermal Comfort and Sustainable Thermal Standards for Buildings”, Energy and Buildings, vol. 34, pp. 563-572, 2002.
[2] M. Santamouris and F. Allard. Natural ventilation in buildings: A design handbook. Earthscan, 1998.
[3] X. Shi, Y. Zhu, J. Duan, R. Shao and J. Wang, “Assessment of pedestrian wind environment in urban planning design”, Landscape and Urban Planning, vol. 140, pp. 17-28, 2015.
[4] DS. Park, “Very low energy homes in the United States: perspectives on performance from measured data”, Energy and Building, vol. 41, pp. 512-20, 2009.
[5] U. Passe and F. Battaglia, Designing Spaces for Natural Ventilation: An Architect’s Guide. Routledge, 2015.
[6] M. Liddamant, A Guide to Energy Efficient Ventilation. Conventry: Air Infiltration and Ventilation Centre, 1996.
[7] G.S. Brager and R. de Dear, “A Standard for Natural Ventilation”, ASHRAE Journal, 2000.
[8] E Maldonado, “Synthesis of barrier and challenges: Why natural ventilation?”, AIOLOS Workshop, 1996.
[9] Y. Tominga, A. Mochida, R. Yoshie, H. Kataoka, T. Nozu, M. Yoshikawa and T. Shirasawa, "AIJ guidelines for practical applications of CFD to pedestrian wind environment around buildings", Journal of Wind Engineering and Industrial Aerodynamics, vol. 96, pp. 1749-1761, 2008.
[10] T. Kubota, M. Miura. Y. Tominaga and A. Mochida, “Wind tunnel tests on the relationship between building density and pedestrian-level wind velocity: Development of guidelines for realizing acceptable wind environment in residential neighbourhoods,” Building and Environment, vol. 43, pp. 1699-1708, 2008.
[11] P. F. Linden, “The Fluids Mechanics of Natural Ventilation”, Annual Review of Fluid Mechanics, vol. 31. pp. 201-238, 1999.
[12] N. Baker and M. Standeven, “Thermal comfort for free-running buildings”, Energy and Buildings, vol. 23, pp. 175-182, 1996.
[13] G.C. de Graca, N. R. Martins and C. S. Horta, “Thermal and airflow simulation of a naturally ventilated shopping mall”, Energy and Buildings, vol. 50, pp. 177-88, 2012.
[14] T. Kim, K. Kim and B.S. Kim, “A wind tunnel experiment and CFD analysis on airflow performance of enclosed-arcade market in Korea”, Building and Environment, vol. 45, pp.1329-38, 2010.
[15] S. Murakami and Y. Morikawa, “Criteria for assessing wind-induced discomfort considering temperature effect”, Journal of Architecture, Planning and Environment Engineering, vol. 358, pp. 9-17, 1985.
[16] M. Garmano and C. A. Roulet, “Multicriteria assessment of natural ventilation potential”, Solar Energy, vol. 80, pp.393-401, 2006.
[17] C.H. Liu, W. C. Cheng, T. C. Y. Leung and D. Y. C. Leung, “On the mechanism of air pollutant re-entrainment in two-dimensional idealised street canyons”, Atmospheric Environment, vol. 45, pp. 4763-9, 2011
[18] J. Hummelgaard, P. Juhl, K. O. Sabjornsson, G. Clausen, J. Toftum and G. Langkilde, “Indoor air quality and occupant satisfaction in five mechanically and four naturally ventilated open-plan office buildings”, Building and Environment, vol. 42, pp. 4051-4058, 2007.