Hello! I'm looking to get some thoughts on the right way to model mechanical systems in EnergyPro 9 for a performance compliance model for a commercial laboratory/innovation/research building. The model only includes the tenant improvements scope. The building is connected to a central utility plant that is in the core and shell scope. The CUP includes boilers, chillers, cooling towers, and AHUs. The building has office and lab spaces. Office spaces have fan coil units providing heating and cooling, with VAV fans. Lab spaces have fan coil units with VAV fans providing cooling only, and terminal VAV boxes providing heating.
The way I initially modeled these FCUs was "Chilled Water VAV" - "Single Zone" with heating coil set to "Hot Water Hydronic" for office spaces, and "w/Terminal Boxes" with heating coil set to "No Heating Provided" for lab spaces. All FCU fans were set to "Variable Speed Drive." However, most spaces, both office and lab, had many heating unmet load hours, even when the model complied energy-wise. I tried multiple approaches to get rid of them, but nothing fixed the issue.
Then I started thinking I was modeling the system wrong. When I changed the system type to "Four Pipe Fan Coil System" for office spaces, the number of UMLHs dropped significantly, but the energy use increased, partially because this system type can't be modeled with variable speed drive fans (I had to use "Constant Volume" instead).
Does anyone know the right approach to model this? Is the second way described above the way to go? Any feedback would be helpful. Thank you!
