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

[Christian Kaltreider]

Hi Everyone,

 

I have not seen my specific situation adequately addressed in the LEED
documentation, so I would be interested to hear others' 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 pumps.the 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 (that's 4 models.Step 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 building.

 

Thanks for any thoughts/opinions you may have,

Christian    

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