VAV-107 - page 8

8
TOTALPRESSURE
C
OptimumEfficiency Selection Chart
A) Enter the chart with the specified volume
andstaticpressure to find themost efficient
selection.
B) Since the chart is based on total pressure,
the velocity pressure must be determined
for the fan selected in A above and added
to the static pressure to arrive at a total
pressure.Velocitypressure isdeterminedby
the following formula
The fanareas areonpage5.
VP=
(
FanArea x 4005
)
2
CFM
EXAMPLE: 40,000CFMat 4.0" SP
A) Enter the chart with40,000CFMand
4.0" SP.Entry falls into80%efficiency
area for aModel 4450-B6-1760.
B) DetermineTP -
TP=SP+VP
TP=4.0= .86=4.86
VP=
(
10.8 x 4005
)
2
= .86
40,000
Refer toChicagoBlower’s
fan.net
selectionprogram
for performance fancurves
andsounddata.
Contact your local
ChicagoBlower sales
engineer for software
andassistance
EXAMPLE: MODEL4450-B6-1760
Themodel number indicates the following:
FanDiameter
= 44-1/2"
HubSeries
= B
Number of Blades = 6
FanSpeed
= 1760RPM
VAV Fan
Model
Numbers
Thischartpresentsageneral selectionmethodforChicagoBlowerVAVVaneaxialFans.All fansse-
lectedfromthischart shouldbecheckedforexacthorsepowerandoperatingcharacteristicsbycon-
sulting the individual fancurve for that selection.
USINGTHESELECTIONCHART
C) Re-enter the chart with40,000CFM
and4.86TP.The selection remains
4450-B6-1760.
DetermineapproximateHP
HP= CFMxTP = 40,000 x 4.86 =38
6362 x eff
6362 x .8
C)Re-enter thechartwith thespecifiedvolume
and calculated total pressure to verify your
original selection.
D)Approximatehorsepower of theselected fan
maybe determinedbyusing thechart effi-
ciency for the selected fan in the following
formula:
E) Refer to the individual fan curve for exact
BHPandpossibleenergy savings by utiliz-
ingadivergingoutlet cone.
HP=
6362 x eff
CFMxTP
The following information is
Chicago Blower Design 47V
mationmust becomplete toa
TOTALPRESSURE
1,2,3,4,5,6,7 9,10,11,12,13,14,15,16
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