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Abstract

Local mean age, which is a very useful indicator of air change efficiency, may be predicted at design stage by post-processing the results of a computational fluid dynamics (CFD) analysis that has been used to establish the internal air movement characteristics. The local mean age may be determined by a number of procedures. In this paper the use of the zonal method, which is very efficient in terms of computer power, is investigated and compared with alternatives based on the age of air transportation equation and the measurement of contaminant concentration. It is concluded that the effect of turbulent diffusion on air distribution patterns is very slight, with the implication that the zonal method provides an extremely efficient means of assessing the air change efficiency within ventilated buildings. It is also concluded that the type and locations of objects within a space are as important as the method of introducing the air supply in determining the room airflow patterns and local air change efficiency.

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References

Sandberg M.

The multi-chamber theory reconsidered from the viewpoint of air quality standards

Building and Environment 19(4) 221-233 (1984)

Etheridge D. and Sandberg M. Building ventilation: theory and measurement ( Chichester : Wiley) (1996)

Matsumoto H. and Kato M. A numerical method for predicting age of air in rooms Proceedings , International Symposium on Room Air Convection and Ventilation Effectiveness, University of Tokyo, pp 339-344 (1992)

Gan G. and Awbi H.B.

Numerical prediction of the age of air in ventilated rooms

Proceedings, Roomvent '94, Air Distribution in Rooms, Poland pp 15-28 (1994)

Versteeg HK and Malalasekera W. An introduction to computational fluid dynamics ( Harlow : Longman) (1995)

Simons M.W. and Waters J.R.

The effect on ventilation effectiveness parameters of various ventilation strategies

Proceedings, 17th AIVC Conference, Optimum Ventilation and Flow Control in Buildings, Gothenburg, pp 457-466 (1996)

Simons M.W. and Waters J.R.

Local ventilation effectiveness parameters in ventilation system design

Building Sero. Eng. Res. Technol. 19(3) 135-140(1998)

Sutcliffe H. A guide to air change efficiency AIVC Technical Note 28 ( Coventry: Air Infiltration and Ventilation Centre) (1990)

Simons M.W. and Waters J.R.

Modelling supply devices in order to predict improvements in internal air quality

Proceedings, 19th AIVC Conference, Ventilation Technologies in Urban Areas, Oslo, pp 36-46 (1998)

Local mean age of air: Predictive techniques compared

Abstract

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References