[Bldg-sim] pro-rating fan power to supply/return fans per 90.1-2007?

[Nick Caton]

Last time I did this, I entered 0.00 kW/CFM for the return fans, and all
of the calculated kW/CFM for the supply fans - better to keep it in one
place imho to avoid the headache of explaining it.  Just got news that
project wrapped up review with a silver rating this week =).

 

If you wanted to distribute the power regardless, I'd do it by weighting
with the airflow amounts.  Generally, I don't think it matters, so long
as you can backtrack your steps if asked to explain yourself ;).

 

~Nick

 

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

Smith & Boucher Engineers

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

www.smithboucher.com 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of James
Hansen
Sent: Tuesday, March 15, 2011 2:05 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] pro-rating fan power to supply/return fans per
90.1-2007?

 

App G says that if the proposed building has return fans, the baseline
building is to be modeled with them as well, sized either at the minimum
required to ensure ventilation, or 90% of the supply volume, whichever
is greater.  And the fan power calculations show that the KW allowance
is for all supply, return, exhaust and relief fans combined.  

 

How do you generally pro-rate the fan power between supply and return
fans in the baseline model?  Ultimately it probably doesn't make too
much difference, but is there an actual ruling that tells you how to do
this?

 

Thanks,

 

GHT Limited
James Hansen, PE, LEED AP

Senior Associate

1010 N. Glebe Rd, Suite 200

Arlington, VA  22201-4749

703-338-5754 (Cell)

703-243-1200 (Office)

703-276-1376 (Fax)

www.ghtltd.com <http://www.ghtltd.com/> 

 

 

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