[Bldg-sim] LEED Treatment of District Systems Pump Energy

Christopher Schaffner chris at greenengineer.com
Wed Oct 12 10:51:29 PDT 2011


You need to have an apples to apples comparison, and you need to account for
the pump energy. 

As you indicate, the Step 2 baseline, is a standalone building, System #7,
with pump energy included.

Your step 2 Proposed Case should account for the all pumping energy in some
way. You have variable primary pumping, so the requirement to model
secondary pumping in the building is not applicable, but you still need to
account for all the pumping energy. Whether it is modeled in the plant or
building is irrelevant. I'd probably model it in the building for simplicity
sake. 

Your step 1 models should have identical plant conditions. If all the
pumping is in the plant, then I would leave the pump energy out of both
Step 1 cases. 

--

Chris Schaffner, PE
LEED Fellow
Founder and Principal

The Green Engineer, LLP
Sustainable Design Consulting
50 Beharrell Street
Concord, MA 01742
T: 978.369.8978
M:978.844.1464
chris at greenengineer.com
www.greenengineer.com

The Green Engineer, LLP is a Certified B Corporation

From:  Christian Kaltreider <ckaltreider at sudassociates.com>
Date:  Wed, 12 Oct 2011 08:47:15 -0400
To:  "'Quitadamo, Bob'" <bquitadamo at RDKEngineers.com>
Cc:  <bldg-sim at lists.onebuilding.org>
Subject:  Re: [Bldg-sim] LEED Treatment of District Systems Pump Energy

Thanks for this information, Bob.  You are correct that I¹m referring to the
earlier guideline (Required Treatment of District Thermal Energy in LEED
Version 2.2 and LEED for Schools, Version 1.0, 2008).
 
I should have been clearer in my post:  This is a LEED 2.2 project, and the
model was originally created using the Version 1 guidance referenced above.
This project was started before the newer 2010 document (Version 2).  The
model was submitted using the Step 1, Step 2 method of Version 1.  I am now
trying to address the reviewer¹s comments.  I did not create the original
model, but I have inherited it since the original modeler is not here any
longer.  For addressing the comments, I think I should maintain the Version
1 format in which we submitted.
 
I¹ll do what seems to be most fair and accurate based on what I read in both
documents and the main intent of apples-to-apples comparisons.  I was just
hoping someone else out there had come across this situation.
 
Thanks again,
Christian  
 

From: Quitadamo, Bob [mailto:bquitadamo at RDKEngineers.com]
Sent: Tuesday, October 11, 2011 5:19 PM
To: Christian Kaltreider
Subject: RE: [Bldg-sim] LEED Treatment of District Systems Pump Energy
 
I think you may be referring to an outdated USGBC guidelineŠThe most current
is here http://www.usgbc.org/ShowFile.aspx?DocumentID=7671 You should only
have to model option one OR option two, whichever you believe to be more
beneficial.
 
Bob Quitadamo | Mechanical Energy Engineer
 
RDK Engineers
Seaport Center, 70 Fargo Street, Suite 800, Boston, MA 02210
P: (857) 221-5927 | F: (617) 345-4226 | M: (978) 482-5629
bquitadamo at rdkengineers.com
http://www.rdkengineers.com <http://www.rdkengineers.com/>
 
 
 
 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Christian
Kaltreider
Sent: Tuesday, October 11, 2011 2:44 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] LEED Treatment of District Systems Pump Energy
 
Hi Everyone,
 
I have not seen my specific situation adequately addressed in the LEED
documentation, so I would be interested to hear others¹ opinions on the
matter:  
 
I am modeling a building which relies on a central plant for heating and
cooling.  The plant serves only a few buildings.  Heating enters the
buildings as HW, not steam.  My building is designed such that there are no
hot water pumpsŠthe BAS communicates back to the central plant pump system,
which adjusts flow appropriately.  All flow within the building is
controlled by valves.  My basic question is, in which models do I include HW
pump energy (that¹s 4 modelsŠStep 1 Baseline and Proposed, and Step 2
Baseline and Proposed)?
 
Here are my thoughts.  For certain I need to include HW pumps in the Step 2
Baseline, as for any Baseline using System 7.  That leaves only 3 models to
ponder.  The LEED guidance I have read leads me to believe I should include
HW pumps in Step 1 Baseline as well.  The intention of Step 1 is to model
the buildings independent of the central plant, which would lead me to not
include the HW pump energy in my Step 1 Proposed model.  Am I now cheating
by including the pump energy in the Baseline but not the Proposed for Step
1?  
 
For Step 2, LEED documentation indicates that secondary pump energy needs to
be modeled in the proposed aggregate building/DES model.  This would lead me
towards not modeling the central plant pumps, but again, is that cheating?
A portion of the central plant pump energy is certainly being used to push
water through my buildingŠ
 
Thanks for any thoughts/opinions you may have,
Christian    
 

 

 

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