Twenty three papers from the ninth AIVC Conference, titles as follows: Keynote speech: Air Infiltration and Ventilation; Natural airflows between roof, subfloor and living spaces; Experimental analysis of air diffusion in large space; Determination of ventilation efficiency based upon short term tests; Ventilation strategies in the case of polluted outdoor air situations; Ventilation generated by a fluctuating pressure differential; Air motion in the vicinity of air-supply devices· for displacement ventilation; integral mass mass balances and pulse injection tracer-techniques; Commercial bu
Sandberg and Skaret differentiate between the terms air change efficiency and ventilation effectiveness. Air change efficiency is a measure of how effectively the air present in a room is replaced by fresh air from the ventilation system whereas ventilation effectiveness is a measure of how quickly an air-borne contaminant is removed from the room. The AIVC guide covers ventilation effectiveness and related concepts. It shows the origins of the concepts used, provides proofs of essential formulae, and suggests standard symbols and definitions.
The concentrations of indoor pollutants should be maintained below recommended values at all occupied locations at any time. A design method based on minimal air change rates may not be satisfactory, since the ventilation effectiveness is determined not only by the nominal air exchange rate but also many other factors, such as the airflow pattern the space, location of contaminant sources, and properties of the contaminants. It is the objective of the present study to investigate numerically the effect of airflow patterns due to the various factors of ventilation effectiveness.
Numerical modelling is performed to predict air movement, thermal comfort level and contamination distribution within an open office space. The office located in the building interior has a concentrated thermal load at its center and is conditioned by cool air delivered from a ceiling-mounted linear diffuser. the air velocity and temperature distributions and contaminant dispersion in the office are calculated for three different cooling loads and air exchange rates with a three-dimensional turbulent finite difference model.
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