irs 179d guidelines

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i'm currently looking at the requirements for modeling a building to
demonstrate energy savings per the epact 2005/irs 179d requirements & am
trying to determine the proper method for calculating baseline fan
power. has anyone else done this yet?

per the NREL manual, Appendix G Section, Wording Changes and
Corresponding Sections in Standard 90.1-2001:

"G3.1.2.9 Supply Fan Power: The Reference Building model fan power
shall be determined based on ? 6.3.3.1 in Standard 90.1-2001"

in 90.1-2001 section 6.6.3.1 is the section with the table that lists
how to calculate the allowable system fan power.

my question is, "for epact 2005/irs 179d energy modeling is the correct
supply fan power to use in the baseline building the same as the
allowable fan system power?" this seems odd when comparing it to
90.1-2004 and having to calculate a baseline fan power (table g3.1.2.9)
in lieu of using the fan power limitation (6.5.3.1) and plugging that
number into the equation Pfan listed in section g.3.1.29. it sort of
just seems too easy.

regards,
patrick

Patrick J. O'Leary, Jr.'s picture
Joined: 2011-09-30
Reputation: 200