Our proposed project is to add about 30,000 square feet to an existing 55,000 square foot University science building. The existing building is LEED Gold under NC-2009. We hope to pursue LEED-BD+C certification in v4. The addition will utilize steam and chilled water from the existing central plant. All downstream systems and equipment will be separate from the existing building.
What is the best approach to take in order to avoid modeling the entire building? Should we treat the central plants as District Energy Systems? I have seen an interpretation (ID #li-5496) that would allow proportioning energy use from the central plant. However, this seems to be for LEED v2 and I'm guessing may not apply.
Thanks for your help!