[BLDG-SIM] Question about Fan Power
Vikram Sami
VSami at lasarchitect.com
Thu Jul 5 13:12:10 PDT 2007
So I'm trying to calculate fan power, and came across this mindbender
Pfan = 746 / (1 - e[ -0.2437839 × ln( bhp ) - 1.685541 ]) × bhp
Having done the hard part (I figured out how to automate the process in XL with just the CFM input using the natural log function ), I have only one question - does the bhp (highlighted at the end) go in the numerator or denominator of the equation?
i.e. - Should the equation read
Pfan = 746 / [(1 - e[ -0.2437839 × ln( bhp ) - 1.685541 ]) × bhp]
Or
Pfan = [746 / (1 - e[ -0.2437839 × ln( bhp ) - 1.685541 ])] × bhp
Any help is much appreciated.
Thanks
Vikram Sami, LEED AP
Direct Phone 404-253-1466 | Direct Fax 404-253-1366
LORD, AECK & SARGENT ARCHITECTURE
1201 Peachtree Street NE, Suite 300, Atlanta, GA 30361
Responsive Design * Technological Expertise * Exceptional Service
www.lordaecksargent.com
Please don't print this email unless you really have to.
One tree makes 16.67 reams of copy paper or 8,333.3 sheets
~Conservatree, September 2002
**************************************************************************
G3.1.2.9 Supply Fan Power. System fan electrical power
for supply, return, exhaust, and relief (excluding power to fanpowered
VAV boxes) shall be calculated using the following
formulas:
Pfan = 746 / (1 - e[ -0.2437839 × ln( bhp ) - 1.685541 ]) × bhp
where
Pfan = electric power to fan motor (watts) and
bhp = brake horsepower of baseline fan motor from Table
G3.1.2.9, where cfm represents design supply flow
rate.
***************************************************************************
===========================
You received this e-mail because you are subscribed
to the BLDG-SIM at GARD.COM mailing list. To unsubscribe
from this mailing list send a blank message to
BLDG-SIM-UNSUBSCRIBE at GARD.COM
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20070705/f1e1f074/attachment-0002.htm>
More information about the Bldg-sim
mailing list