6.2 Fans
223
Fig. 6.22 Effect of natural
ventilation on the fan
characteristic curve
Fan curve
Fan curve
+
Natural ventilation
Fan curve
-
Natural ventilation
Airflow rate
Pressure
Fig. 6.23 Use of fan curve
to determine power
consumption
1
1
2
2
3
3
4
5
4
5
Airflow rate
Power
Pressure
• P s : Static pressure (Pa).
• Q: Airflow rate (m
3 s
−1 ).
• Pw shaft : Power input to the fan shaft (W).
When selecting a fan, it must be borne in mind whether the manufacturer’s data
refer to the P s or the P T (Fig. 6.24). As a general criterion, one should choose the
fan with the maximum efficiency closest to the intended operation point.
223
Fig. 6.22 Effect of natural
ventilation on the fan
characteristic curve
Fan curve
Fan curve
+
Natural ventilation
Fan curve
-
Natural ventilation
Airflow rate
Pressure
Fig. 6.23 Use of fan curve
to determine power
consumption
1
1
2
2
3
3
4
5
4
5
Airflow rate
Power
Pressure
• P s : Static pressure (Pa).
• Q: Airflow rate (m
3 s
−1 ).
• Pw shaft : Power input to the fan shaft (W).
When selecting a fan, it must be borne in mind whether the manufacturer’s data
refer to the P s or the P T (Fig. 6.24). As a general criterion, one should choose the
fan with the maximum efficiency closest to the intended operation point.