[Equest-users] Exhaust fan power not calc'ed in TRACK-SUPPLY mode

[Erik Kolderup]

Hi,

Anyone encountered this apparent eQUEST bug?

I specify a zone exhaust fan and choose the control option "TRACK-SUPPLY"
because I want all the air from the zone exhausted and for the exhaust flow
to follow the supply air flow provided by the VAV box. I enter a kW/cfm for
the exhaust fan and specify variable speed control.

The result is that only supply and return fan power get calculated. Hourly
reports show that the return air flow is correctly reduced by the amount
that's going to exhaust. Hourly reports also show that exhaust flow at the
zone level is correctly matching supply air flow. However, the exhaust fan
power disappears. Changes to the kW/cfm (or to the SP input) have no impact
on results. Looks to me to be a bug. The same problem seems to happen in
the "TRACK-BOTH" exhaust fan control mode.

I was able to verify that the exhaust fan power is calculated correctly if
I enter a specific exhaust flow value and choose the "TRACK-EXHAUST"
control mode.

(And as far as I can tell, there is no hourly variable for exhaust fan
power. I could find it only by subtracting hourly supply and return fan
power from the total vent fan end use.)

-Erik

*Erik Kolderup, PE, LEED AP*
erik at kolderupconsulting.com | 415.531.5198 | www.kolderupconsulting.com
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