Hi All,
Appendix G3.1.2.9 of ASHRAE 90.1-2007 gives the formula for systems 1
& 2:Pfan = CFMs x 0.3where CFMs is the supply fan airflow rate in
cfm and Pfan is in watts. I just noticed that in SI version, the
formula is the same Pfan = CFMs x 0.3 where Pfan is also in watts but
CFMs is in lps. Which is version correct? I have already looked into the erratas and addendum but did not find any corrections.
Thank you all in advance.
Jaigath Chandraprakash
The IP version is correct.
Jason
Yes, it appears to be part of the SI edition that hasn't been fully
converted from IP.
For System 7 (I haven't done a system 1 or 2), I used the SI calc and found
that it matched the fan power of a VAV system in E+ with 1300Pa pressure
drop and about 70% fan efficiency. You just have to do half of the calc in
IP units!