high electricity use for chiller
I am trying to develop a LEED v4.1 model for a 38,000 ft2 two story school building. The ASHRAE 90.1-2016 Appendix G baseline building for this appears to be a System 6, so one packaged VAV DX cooled, electrically heated system per floor, with PFP terminal units. The proposed building uses an air-cooled chiller and a natural gas boiler. I developed the baseline building first, then changed the two packaged systems out for two air handling units, and the chiller and boiler loops get created automatically. The chiller is water-cooled, so I switched that out for an air-cooled one.
I did this just to get an early indication of any improvement due to switching to chilled water. The packaged system cooling coils have a COP of 3, the chiller has a COP of 5.5. When I run the simulation, the baseline end-uses 1236.60 GJ in cooling electricity, while the proposed system end-uses a whopping 2967.77 GJ This does not seem right, given the COPs used, and destroys any hopes of making LEED points or even complying with Appendix G? Any thoughts would be appreciated.
I am also entertaining passing this project (and its sister project) on to anyone interested in and capable of doing LEED v4.1 energy modeling on short notice (1 month) - I can provide the geometry input at this point. You can contact me at mattkoch@scitex.us if interested. (OpenStudio Application 1.2.1)
