LEED DES Option 1 for buildings with heat pumps

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I have a group of 3 buildings that are served by the same boilers, cooling tower for LEED certification. Two of the buildings have water source heat pumps, while the third one has 4-pipe fan coil units (which is served by a chiller in the central plant). The central plant serving all these buildings are located in the building with fan coil units.

Due to the unavailability of LEED Group Certification forms on LEED online, we were advised to pursue Master Site certification. Under that scheme, it appears that modeling the central plant as a DES is the only option to go. We are starting out with Option 1 in the "Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 - Design & Construction" to see how things work out. But regardless of Option 1 or 2, it seems there is no guidance in that document to model a WSHP system, and it appears that for Option 1, I have to model the WSHPs as fan coils. Is that a correct assumption? I came across LEED Interpretation 5234 (attached), but I don't think that applies to my scenario since that is for a geothermal loop with supplemental cooling tower and boiler.

I know this is not a direct eQuest related question, but there seems to be quite a few people out here with experience in LEED projects. Hopefully, someone has dealt with a situation like this and can provide some suggestions.

Thank you,

Ritwik Kakati, LEED Green Associate

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Joined: 2012-07-12
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Interesting project and interpretation! Are you unsure if the project will reach the points floor in Option 2? If there is any cushion at all, seems like you could just commit to that approach.

I had a long email written in response about several poor options to use district heat/cool to condition your condenser loop which is a horrible idea, or use district heating only - still not a great solution, or modeling all the buildings together and petition to share the points - still the best of a bad slate of options. Deleted all of that...

What I ended up with was to start with Option 2 and see if you are comfortably above the points floor. If so, you won't need all of this anyway. But it seems like you must be checking Option 1 since you aren't sure yet. If that doesn't work, submit a CIR to request use of Option 2, even if ending up below the floor. Then you'll be covered if you come up just short at the end. This makes sense to me assuming you come in at least close to the floor.

It's the best match of modelability and intent of the credit, given the limitations for the DES guidance.


David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP

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Joined: 2012-05-08
Reputation: 1