SET Proceedings 2978-4387 Caravel Press 10.65582/set.2005.037 2005.037 Buoyancy-driven Displacement Natural Ventilation in a Single-zone Building with Two-level and Three-level Openings FanYun LiDeying Beijing Institute of Civil Engineering and Architecture, Beijing, China 23092005 4 1 978-7-112-07718-2 168 171 23 September 2005 © 2005 Copyright WSSET 2005

Displacement natural ventilation, dense ambient air is entrained at low-level openings by thermal buoyancy sources (generally, heating elements) and displaces the lighter air in the building out through high-level openings. Since the incoming air is essentially at the low level, a thermal stratification develops between the fresh air and the air previously in the building. Theoretical solutions for thermal stratification and airflow rates were obtained for buoyancy-driven displacement natural ventilation in a single-zone building with two-level openings and three-level openings. The effects of openings sizes on stratification interface level and volume flux were studied using Newton iterative Method. It was found that for a given ventilation mode, the location of the stratification interface is a function of the geometrical parameters only and independent of the strength of buoyancy sources.

 displacement natural ventilation two-level openings three-level openings stratification interface level volume flux 23 to 25 September 2005 4th International Conference on Sustainable Energy Technologies SET2005 4 Jinan, China Ma Renmin, International development in research of indoor air quality in non-industrial buildings, HV&AC, 1999, 29(2): 38~41. Fan Cunyang, Lin Zhongping, Status and development of residential equipment, HV&AC, 2002,32(4): 34~42. A. Krishan, Climate Responsive Architecture: A Design Handbook for Energy Efficient Buildings, McGraw-Hill, New York, 2001. T. Willmert, The return of natural ventilation, Architectural Record 189 (7) (2001) 137~148. Z.D. Chen, Yuguo Li, Buoyancy-driven displacement natural ventilation in a single-zone building with three-level openings, Building and Environment, 37 (2002) 295~303. Linden PF, Lane-SerC GF, Smeed DA, Empting filling boxes: the fluid mechanics of natural ventilation. Journal of Fluid Mechanics, 1990, 212:309~35. Z.D. Chen, Y. Li, J. Mahoney, Experimental modeling of buoyancy-driven flows in buildings using a fine-bubble technique, Building and Environment, 36 (2001) 447~45.