My proposed design for lab utilizes a heat recovery chiller connected to geo-exchange. There is a 40 ton process chilled water load on the heat recovery chiller. The baseline system for this building is System 6 for non lab spaces and system 5 for the lab spaces. As such, there are no chillers in the baseline model. My understanding is that the process load is to be modeled the same in both models. However, it would not be possible to model the baseline with a heat recovery chiller connected to geo exchange as there would nothing to reject the heat to (no heat load for recovery or to balance the geo loop). How do I go about modeling the 40 ton process chilled water load? Would it be acceptable to run a separate simulation of the proposed model without the 40 ton process chilled water load to determine the energy use associated with it, then simply add this energy use to the baseline model results?
You rely on LEEDuser. Can we rely on you?
LEEDuser is supported by our premium members, not by advertisers.
Go premium for
Tyler Thumma
7GroupLEEDuser Expert
64 thumbs up
July 18, 2024 - 9:46 am
The approach you describe would be the most conservative option as it would hold the process chiller energy use identically between the Baseline and Proposed models. However, I would also recommend submitting an Exceptional Calculation in which the Baseline process chilled water is supplied by a standard chiller at minimum code efficiency. The process chilled water load would be identical, but you would be able to show savings associated with the more efficienient heat recovery chiller plant. You would need to provide documentation to support whatever type of Baseline chiller you define as "standard" based on what is standard practice for a typical newly constructed facility.