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On the competition between lateral convection and upward displacement in a multi-zone naturally ventilated space

Published online by Cambridge University Press:  24 July 2012

Andrea S. Kuesters  and
Andrew W. Woods
Andrea S. Kuesters
Affiliation:
BP Institute, University of Cambridge, Cambridge CB3 OEZ, UK
Andrew W. Woods*
Affiliation:
BP Institute, University of Cambridge, Cambridge CB3 OEZ, UK
*
†Email address for correspondence: andy@bpi.cam.ac.uk
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Abstract

We consider the flow which develops when two separate spaces maintained at different temperatures, both in excess of the exterior temperature, are connected through high and low level openings to a central atrium in which there is negligible heat load but which can naturally ventilate through high and low level openings to the exterior. We show that with a small temperature contrast between the spaces or large openings from the atrium to the exterior, upflow displacement ventilation develops in each of the spaces, with air entering from the atrium at low level and exiting at high level. However, with a larger temperature contrast between the spaces or small openings between the atrium and the exterior, a convective circulation develops between the spaces, with upflow in the warmer space and downflow in the colder space. Exterior air, which may enter the atrium at low level, flows into the warmer space along with the air from the colder space. At high level, air flows back into the atrium from the warmer space, and then either vents from the building or flows into the colder space. In this convection dominated flow regime, the colder space is a net heat sink, whereas with the upward displacement ventilation, this space acts as a net heat source. This can have significant implications for energy usage and on the build up of contaminants in each of the spaces. We also show that in both steady flow regimes, the air at mid-level in the atrium is unventilated and stagnant. We discuss the relevance of our model for controlled natural ventilation in large public buildings such as shopping malls where individual shops often maintain temperatures independently of the central atrium-space.

JFM classification

Convection: Convection in cavities Flow Control: Flow Control
Type
Papers
Information
Journal of Fluid Mechanics , Volume 707 , 25 September 2012 , pp. 393 - 404
Copyright
Copyright © Cambridge University Press 2012

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References

1. Baines, W. & Turner, J. 1969 Turbulent buoyant convection from a source in a confined region. J. Fluid Mech. 37 (1), 51–80.CrossRefGoogle Scholar
2. Bolster, D. T. & Linden, P. F. 2007 Contaminants in ventilated filling boxes. J. Fluid Mech. 591, 97–116.CrossRefGoogle Scholar
3. Bower, D. J., Caulfield, C. P., Fitzgerald, S. D. & Woods, A. W. 2008 Transient ventilation dynamics following a change in strength of a point source of heat. J. Fluid Mech. 614, 15–37.CrossRefGoogle Scholar
4. Chenvidyakarn, T. & Woods, A. W. 2005 Multiple steady states in stack ventilation. Build. Environ. 40, 399–410.CrossRefGoogle Scholar
5. Cooper, P. & Linden, P. F. 1996 Natural ventilation of an enclosure containing two buoyancy sources. J. Fluid Mech. 311, 153–176.CrossRefGoogle Scholar
6. Flynn, M. R. & Caulfield, C. P. 2006 Natural ventilation in interconnected chambers. J. Fluid Mech. 564, 139–158.CrossRefGoogle Scholar
7. Gladstone, C. & Woods, A. W. 2001 On buoyancy-driven natural ventilation of a room with a heated floor. J. Fluid Mech. 441, 293–314.Google Scholar
8. Holford, J. M. & Hunt, G. R. 2003 Fundamental atrium design for natural ventilation. Build. Environ. 38, 409–426.Google Scholar
9. Holford, J. M. & Woods, A. W. 2007 On the thermal buffering of naturally ventilated buildings through internal thermal mass. J. Fluid Mech. 580, 3–29.CrossRefGoogle Scholar
10. Hunt, G. R. & Linden, P. F. 2004 Displacement and mixing ventilation driven by opposing wind and buoyancy. J. Fluid Mech. 527, 27–55.CrossRefGoogle Scholar
11. Kaye, N. G. & Hunt, G. R. 2004 Time-dependent flows in an emptying filling box. J. Fluid Mech. 520, 135–156.CrossRefGoogle Scholar
12. Kuesters, A. S. & Woods, A. W. 2011 The formation and evolution of stratification during transient mixing ventilation. J. Fluid Mech. 670, 66–84.CrossRefGoogle Scholar
13. Linden, P., Lane-Serff, G. & Smeed, D. 1990 Emptying filling boxes: the fluid mechanics of natural ventilation. J. Fluid Mech. 212, 309–335.Google Scholar
14. Lishman, B. & Woods, A. W. 2009a On transitions in natural ventilation flow driven by changes in the wind. Build. Environ. 44, 666–673.CrossRefGoogle Scholar
15. Lishman, B. & Woods, A. W. 2009b The effect of gradual changes in wind speed or heat load on natural ventilation in a thermally massive building. Build. Environ. 44, 762–772.Google Scholar
16. Mott, R. W. & Woods, A. W. 2011 Natural ventilation driven by periodic gusting of wind. J. Fluid Mech. 679, 58–76.CrossRefGoogle Scholar
17. Woods, A. W., Fitzgerald, S. D. & Livermore, S. 2009 A comparison of winter pre-heating requirements for natural displacement and natural mixing ventilation. Energy Build. 41 (12), 1306–1312.CrossRefGoogle Scholar
18. Yam, J., Li, Y. & Zheng, Z. 2003 Nonlinear coupling between thermal mass and natural ventilation in buildings. Heat Mass Transfer 46, 1251–1264.CrossRefGoogle Scholar