Our project is located on a University campus with two separate DES buildings. One DES building houses all the chilled water equipment including chillers, pumps, cooling towers, etc. and only provides chilled water. There is a separate DES building which houses all the steam equipment. The DES Guidance indicates that for EAc3 we must commission all upstream equipment if "the DES supplies energy constituting more than 20% of the project building's annual energy cost, as determined using the Proposed Case energy modeling run of either the EAc1 Option 1 or Option 2." Should we be viewing the chilled water plant as one DES and the steam plant as a separate DES? In our case, the CHW plant accounts for 19% of the energy cost of the building and the Steam plant accounts for 9% of the energy cost of the building. Separately, these two plants are less than 20% of the energy cost but combined they would be greater than 20% and thus require commissioning of the DES. Because these are separate systems, should we be required to commission both even though separately they do not account for 20% of the cost? Is there a reason to commission the Steam Plant in this situation? The guidance document does not get detailed enough to answer this question nor are there any CIRs addressing this. Any thoughts? Also, even if the steam(or HHW) and CHW equipment are located in the same physical building, should they be viewed as separate plants?
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Chris Ladner
PartnerViridian
261 thumbs up
May 9, 2012 - 9:34 am
The key word in the DESystem guidance is "system". I feel that the intent of the additional guidance is to ensure that any system (not necessarily plant or utility) that provides more than 20% energy undergoes the same Cx activities as the base building. I would err on the side of commissioning both plants. Otherwise, this may be a good use of a CIR.
James Del Monaco
Sustainability Director, PEP2S Engineering, Inc.
64 thumbs up
May 9, 2012 - 11:03 am
Chris, I appreciate the feedback. We were thinking a CIR might be best since there's really no clear direction available from the USGBC at this point. Erring on the side of commissioning both plants is a great idea, but there are cost implications with that approach.
Chris Ladner
PartnerViridian
261 thumbs up
May 9, 2012 - 11:10 am
I completely understand. You are in a grey area that we have not had to deal with on any of our projects. The DES usually provides more than 20%.