[Equest-users] App G Baseline CHW Pump Power

[Nick Caton]

Oh wow, good to know!   I’ll re-revise the procedure I’ve written up for my next chiller baseline!

Thanks to GBCI for internally ruling this in a way to grant extra performance/points, I suppose!

~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: James Hansen [mailto:JHANSEN at ghtltd.com]
Sent: Wednesday, November 27, 2013 11:41 AM
To: Nick Caton; Christian Kaltreider; Bishop, Bill; Joe Fleming; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] App G Baseline CHW Pump Power

For what it's worth, I've used 22 W / gpm for each system (primary and secondary) for the past few LEED projects, and have not had any comments, given that the LEED "Revised Section 1 4 Table" from Dec 2012 specifically lists that the primary and secondary pumping system should be at 22 W  / gpm.  By the way, if you're not using the Table 1.4 excel spreadsheet to document EAp2/EAc1, you should, because it makes it way easier for GBCI to review your model, and it minimizes the chance and/or severity of comments.

CHW Loop Configuration

Primary/secondary per G3.1.3.10

N/A

N/A

Number of Primary CHW Pumps

1 per chiller per G3.1.3.11

N/A

#

N/A

#

Primary CHW Pump Power

22 W/gpm per G3.1.3.10

N/A



N/A

W/gpm

Primary CHW Pump Flow

Auto-sized with a capacity ratio of 1.0 based on CHW temperatures

N/A

gpm

N/A

gpm

Primary CHW Pump Control

Constant Flow - each primary pump interlocked to operate with associated chiller - G3.1.3.10, G3.1.3.11

N/A

N/A

Number of Secondary CHW Pumps

1 per G3.1.3.10

N/A

#

N/A

#

Secondary CHW Pump Power

22 W/gpm per G3.1.3.10

N/A

W/gpm

N/A

W/gpm

Secondary CHW Pump Flow

Auto-sized with a capacity ratio of 1.0 based on CHW temperatures

N/A

gpm

N/A

gpm

Secondary CHW Pump Control

<300 tons: riding the pump curve
≥300 tons: variable speed

N/A



N/A




Regardless of how ASHRAE has ruled, GBCI makes it pretty clear that you should use 22 W / gpm for both primary and secondary loop pumps.

GHT Limited
James Hansen, PE, LEED AP, BEMP
Senior Associate
1110 N. Glebe Road, Suite 300
Arlington, VA 22201
703.243.1200 (main)
703.338.5754 (direct/cell)
www.ghtltd.com<http://www.ghtltd.com>

From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org> [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
Sent: Wednesday, November 27, 2013 12:32 PM
To: Christian Kaltreider; 'Bishop, Bill'; 'Joe Fleming'; equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] App G Baseline CHW Pump Power

Thanks for bringing that back up  - I thought this remained an ambiguous/grey area indefinitely.

As to potential for squeezing extra performance via power distribution between pumps… I’ve never considered that, but to share my anecdotal experience I typically just dump all the power on the secondary pumps and make the primary pumps “powerless” for simplicity’s sake in documentation/QC.  I suppose for variable-secondary cases that approach might miss out on some baseline energy that would otherwise be burned by a CV primary…

A “logical” approach would be to proportion the ‘system’ 22W/GPM by a ratio to match the pump sizing in the actual design.

That said, I’ve never been told to proportion my pump energies any differently than my simplified approach of dumping it all in one place.

Hope that helps =),

~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<http://www.smithboucher.com>

From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org> [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Christian Kaltreider
Sent: Monday, November 25, 2013 2:26 PM
To: 'Bishop, Bill'; 'Joe Fleming'; equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] App G Baseline CHW Pump Power

Yes, that lays it out pretty clearly.  22 W/GPM system total.

I wonder if future 90.1 versions will prevent gaming of the system (intentional or not) by offering guidance on power allocation among pumps?

Thanks for the helpful replies,
Christian

From: Bishop, Bill [mailto:bbishop at pathfinder-ea.com]
Sent: Monday, November 25, 2013 2:11 PM
To: Joe Fleming; 'Christian Kaltreider'; equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: RE: [Equest-users] App G Baseline CHW Pump Power

Christian,

Confirming what Joe says, an ASHRAE interpretation<https://www.ashrae.org/File%20Library/docLib/StdsInterpretations/IC-90-1-2007-14.pdf> clarified that 22W/gpm is the total power of all baseline CHW pumps.

Regards,
Bill

William Bishop, PE, BEMP, BEAP, LEED AP | Pathfinder Engineers & Architects LLP
Senior Energy Engineer

[cid:image002.jpg at 01CEEB66.339EF4D0]



134 South Fitzhugh Street                 Rochester, NY 14608

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

bbishop at pathfinder-ea.com<mailto:wbishop at pathfinder-ea.com>           www.pathfinder-ea.com<http://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> [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Joe Fleming
Sent: Monday, November 25, 2013 2:07 PM
To: 'Christian Kaltreider'; equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] App G Baseline CHW Pump Power

Almost certain that the GBCI interprets it as a whole system divvy, not each pump with 22W/GPM.

Regards


Joe Fleming  |  PE, LEED AP BD+C, BEMP
Commissioning Agent / Energy Modeler | The Spinnaker Group
561.602.3132 | joe at thespinnakergroupinc.com<mailto:joe at thespinnakergroupinc.com>

From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org> [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Christian Kaltreider
Sent: Monday, November 25, 2013 2:01 PM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] App G Baseline CHW Pump Power

Hello,

In November 2010, around the same time someone was modeling a building that looked like a turkey, there was a conversation on this list about baseline CHW pump power:

http://lists.onebuilding.org/htdig.cgi/equest-users-onebuilding.org/2010-November/006941.html

Part of the discussion was some back and forth about how to apply G 3.1.3.10.  This section calls for baseline pump power to equal 22W/GPM and for the CHW pumping configuration to be primary/secondary.  Some had the opinion that each pump (primary and secondary loops) should have 22 W/GPM assigned to it, while others thought that the total CHW pump system power should sum to 22 W/GPM, and that it was up to the modeler to divvy up the power among pumps as they see fit.  I did not see a clear conclusion.

Does anyone know if a general consensus was reached?

Thanks,
Christian


Christian Kaltreider, LEED AP | Energy Analyst
Sud Associates, P.A. | T 828.255.4691 | F 828.255.4949 | www.sudassociates.com<http://www.sudassociates.com>


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