The project is such that it consists of two major renovations of two college buildings and the construction of a new link between them. The energy model is just of ONE building. However, the distrubution systems are sized for BOTH building and are not located in the SAME building. For example: The heating distribution for the Modeled Building is in the OTHER building NOT being modeled. So, the non-modeled building would foot the bill for providing heat to the modeled building. In other words, the modeled building is not paying for heat. Contriwise, the modeled is cooling both building and does pay for the cooling load of both buildings. If that's not confusing enough, the distribution systems are sized for both building and future work in Phase 3 of the project. So I got a 500 GPM pump for hot water, but I only really need 70 GPM for my building I'm modeling. How can I cleanly and accurately model the pumps for the modeled building? If I model it at 500 gpm than I'm getting beat bad in savings, but if I arbitarily reduce the wattage of the pumps than I risk getting flagged by a reviewer, so what should I do?
You rely on LEEDuser. Can we rely on you?
LEEDuser is supported by our premium members, not by advertisers.
Go premium for
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
September 17, 2012 - 9:27 am
Are you following the District Energy Systems guidance document?
Dawn Kowalik
Administrative AssistantBergmann Associates
6 thumbs up
September 18, 2012 - 1:53 pm
That takes care of the district heating issue, but what about the reduce cooling system load. Remember, the cooling system is sized to service both building from within the LEED project boundry plus a future phase not within the boundry. So, it seems that I could scale down the GPM to match the isolated building's consumption, but how do I translate that into a reduced wattage? Would I use the 22 W/GPM value?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
September 18, 2012 - 2:36 pm
Sounds like both district heating and district cooling. The DES guidance covers both and deals with systems within and outside the project. How you model the pumps could vary depending on which option you use in the DES and where the pumps are in the system.
Dawn Kowalik
Administrative AssistantBergmann Associates
6 thumbs up
September 18, 2012 - 5:03 pm
So if the proposed building's chiller plant becomes a District Cooling source for the project, than, I have district heating and cooling and my System 5 unit becomes a System 7 unit. Then if I follow Option 1 than I can exclude upstream equipment. Since the proposed building houses the thermal plant (chiller) it's considered upstream equipment according the guide, therefore I can ignore that chiller plant. Basically, if I understand this correctly: The heating plant in the other building is ignored and the chiller plant in the project boundry is ignored.. than I am not modeleding any chilling or heating plants. All of this seems to be within the guideliens of the District Thermal guide. Is this assumption correct? What's confusing is that the project boundry is paying for the chiller plant supplying two buildings. USGBC recommends going with Option 2, but it's not mandatory.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
September 18, 2012 - 5:15 pm
Yep under Option 1 you treat the HW and CW as purchased energy. A central plant serving more than one facility is all this takes as I understand it. Option 2 does account for it all and is optimal for capturing all of the efficiencies of a district plant.