[Equest-users] Baseline Fan power calculation

Maria Karpman maria.karpman at karpmanconsulting.net
Mon Mar 25 08:24:47 PDT 2013


FYI, the newest LEED EAp2 spreadsheet (attached) has embedded calculations
for the baseline fan power on Air-Side HVAC Details tab, which I think is
quite handy.

 

Maria 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Bishop,
Bill
Sent: Monday, March 25, 2013 11:01 AM
To: RobertWichert; Nick Caton; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Baseline Fan power calculation

 

Robert,

 

I'm sure Nick is typing furiously as I write this, but I'll probably finish
before him.

 

Taking a quick look at the spreadsheet that Nick attached to his email, it
calculates baseline fan power using the method described in Appendix G and
6.5.3.1.1. Fan efficiency is included in the Pfan calculation per G3.1.2.9.

Fan efficiency is from ASHRAE 90.1, Table 10.8 as described in G3.1.2.9.

 

Regards,

Bill

 

William Bishop, PE, BEMP, LEED AP | Pathfinder Engineers & Architects LLP

Senior Energy Engineer

 

134 South Fitzhugh Street                 Rochester, NY 14608

T: (585) 325-6004 Ext. 114            F: (585) 325-6005

 <mailto:wbishop at pathfinder-ea.com> wbishop at pathfinder-ea.com
<http://www.pathfinder-ea.com/> www.pathfinder-ea.com

P   Sustainability - the forest AND the trees. P   

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of
RobertWichert
Sent: Monday, March 25, 2013 10:52 AM
To: Nick Caton; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Baseline Fan power calculation

 

I believe I have written about this in the past, but since this seems to be
on-topic, I'll bring it up again.

The theoretical fan power equation, Fan BHP = (cfm x static press "w.c.) /
(6356 x fan efficiency) can be used to calculate the theoretical fan BHP,
but you need the fan efficiency.  This seems to be NOT the way the BHP is
being calculated by the spreadsheet that was attached previously.

Is there a reason for that?

Was there an assumed fan efficiency used in the spreadsheet, and was it
based on anything particular, or just a conservative assumption?


Thanks!





Robert Wichert P.Eng. LEED AP BD&C
+1 916 966 9060
FAX +1 916 966 9068
 
 
 
 
 
 
 
===============================================

On 3/25/2013 7:34 AM, Nick Caton wrote:

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.





_______________________________________________
Equest-users mailing list
http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org
To unsubscribe from this mailing list send  a blank message to
EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG

 

  _____  

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.2240 / Virus Database: 2641/5703 - Release Date: 03/25/13

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20130325/7b0f8b2b/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 1459 bytes
Desc: not available
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20130325/7b0f8b2b/attachment-0002.jpeg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Revised Section 1 4 Tables (Dec 2012) downloaded 1.11.13.xls
Type: application/vnd.ms-excel
Size: 741888 bytes
Desc: not available
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20130325/7b0f8b2b/attachment-0002.xls>


More information about the Equest-users mailing list