Lab ACH Setback with Packaged Single Zone Systems

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I am modeling a lab spaces for LEED, and the 90.1-2004 Baseline system is a
Packaged Single Zone. The lab spaces have 12 ACH during occupied periods,
and 6 ACH during unoccupied periods.

Using eQUEST, I cannot seem to get the supply airflow to vary between 12 and
6 ACH. I have fume hood exhaust schedules which control the OA flow rates,
and these are both varying between occupied and unoccupied hours. I have
specified my Min Flow Ratio to 0.5 at the system level, set my Min ACH to 6
at the zone level, and assigned a Min Flow Schedule to the zone level
airflow that matches that of the fume hood exhaust schedule.

I have been outputting hourly variable to check how the system is
performing and right now my supply air is constant at 12 ACH, while the OA
and EA varies between 6 and 12. Is there anyway to get the supply airflow
to vary on a PSZ?

I was able to get this to work in another model with a Reheat Fan System
that was serving multiple zones, but it doesn?t seem right to change the
system type.

Thank you,

Kendra Tupper

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Joined: 2011-09-30
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