[Equest-users] Baseline Fan power calculation

[Nick Caton]

Hi Vamshi,

I advise carefully reviewing the footnotes under Table 6.5.3.1.1A, which include procedure for determining baseline fan power adjustments.


1.       Pfan represents the sum power of all fans in a given baseline system (with exception to baseline systems #6/#8, fan powered VAV boxes).

2.       Again, there is not a separate supply/return power calculation (see answer #1).  You can however account for adjustments present in separate airstreams from the proposed design.

3.       Probably not.  Review the difference between CFMS and CFMD carefully at the cited Table.  A CFM quantity representing the airflow each element encounters (CFMD) should be applied against each pressure drop adjustment, not an 'aggregate' of supply+return.

You may also find the attached resource published by 7group helpful to cement your procedural understanding of how to arrive at the sum total for "A."

Regards,

~Nick
[cid:489575314 at 22072009-0ABB]

NICK CATON, P.E.
SENIOR ENGINEER

Smith & Boucher Engineers
25501 west valley parkway, suite 200
olathe, ks 66061
direct 913.344.0036
fax 913.345.0617
www.smithboucher.com

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of vamshi ranga
Sent: Monday, March 25, 2013 8:17 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Baseline Fan power calculation

Hi All,

I have a doubt regarding calculating fan power as per ASHRAE 90.1-2007.

My proposed system has, supply return and exhaust fans separately with kW and cfm mentioned for each fan.

So, for calculating baseline fan power,

1. should I calculate it separately for each fan type?
2. can I take pressure drop adjustment both in supply and return fan power calculation?
3. should I sum all the cfms of supply, return and exhaust and than apply pressure drop adjustments to aggregated cfm.

Kindly help me out in solving the doubt. If you have any example fan power calculations, or web links those could guide me regarding this, plz do share them.

Thanks in advance.

Regards,
Vamshi.
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