I am modeling a school that is 150,700 SF. There is a welding lab in the
school and it falls within the exceptions of ASHRAE 90.1 2007: G3.1.1
Exception b. ("Peak thermal loads that differ by 10 btuh/sf or more from
the average of the other spaces served by the system..."). The welding
lab is 3,500 SF and I would use System 3 (PSZ-AC) for this space.
When I refer to Table G3.1.1A, one of the notes reads "Where attributes
make a building eligible for more than one baseline system type, use the
predominant condition to determine the system type for the entire
building." Does this allow me to use System 5 (Packaged VAV with Reheat)
instead of System 7 (VAV with Reheat) since the predominant condition
serves 147,200 SF (150,700-3,500)?
This is a LEED project and I would obviously rather use system 5 than
system 7 as my baseline HVAC system.
Thanks,
Otto