2004 Volume 29 Issue 92 Pages 143-150
The Ventilation Standard HASS102 of The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan (SHASE) was revised in November 1997 and The Ventilation Standard HASS102 recommends the ventilation design, which takes into account a ventilation effectiveness in an occupied zone, under the incompletely mixed condition. This index is called Normalized Concentration in an Occupied Zone (C_n), which defined as the ratio of the difference between the average pollutant concentration in an occupied zone and that of the completely mixed indoor air. Furthermore, The Standard of Measuring Method of Ventilation Effectiveness HASS115 was published in order to supplement HASS102 in April 2002. This paper contains three topics. The first is theoretical analysis of Normalized Concentration in an Occupied Zone (C_n) under various returned Airflow rate. The second is C_n measurement by tracer gas methods in model room (3.2m(x)×3.2m(y)×2.8m(z)). The third is numerical analysis, which is corresponding to the experimental conditions. In these measurement and numerical analysis, the prediction accuracy of C_n had the difference about 10% compared with experimental result. Furthermore, the effects of the increment of return air, which induced in a supplied air, are also studied and it is confirmed that the Normalized Concentration in an Occupied Zone (C_n) got closer to 1.0 (the concentration of the completely mixed indoor air) for the increment of return air in supplied air.
