Filter
Top Products
20 TRG-TRC013-EN
notes
period one
Fan Performance
Consider a case where the air resistance through the system is greater than
predicted. Instead of the design operating point A, the actual system resistance
curve intersects the fan performance curve at B, delivering a lower airflow than
intended. The solution to this problem is to either improve the system design or
increase the fan speed. At the higher speed, the system resistance and fan
performance curves intersect at C to deliver the design airflow. The fan must
generate more static pressure to deliver the intended airflow, requiring more
power than expected.
On the other hand, if the system resistance is less than estimated, the actual
system resistance curve falls to the right of the estimated curve.
Instead of operating at the design operating point A, the actual system
resistance curve intersects the fan performance curve at D, delivering a higher
airflow than intended.
airflow
airflow
static pressure
static pressure
surge
region
surge
surge
region
region
%
&
d
e
s
i
g
n
f
a
n
s
pe
e
d
d
e
s
i
g
n
f
a
n
s
p
e
e
d
new
fan
s
pee
d
n
ew
f
an
s
p
eed
$
actual system
resistance curve
actual system
actual system
resistance curve
resistance curve
Higher System Resistance
Figure 30
airflow
airflow
static pressure
static pressure
'
(
new
f
an
s
p
e
e
d
ne
w
f
a
n
s
p
e
e
d
actual system
resistance curve
actual system
actual system
resistance curve
resistance curve
$
surge
region
surge
surge
region
region
d
e
s
i
g
n
f
a
n
s
p
e
e
dd
e
s
i
g
n
f
a
n
s
p
e
e
d
Lower System Resistance
Figure 31