Will the Sizing:Zone:Cooling Minimum Air Flow Fraction input still be used to set minimum air flow for VAV systems even if my Cooling Design Air Flow Method = DesignDay ?
if yes, what is the ideal value used in the industry ? How to set the minimum air flow fraction value ?
The Sizing:Zone, Cooling Minimum Air Flow Fraction input is used in two places as far as I can tell. I doesn't matter which cooling air flow sizing method is used, if this field is entered then it is used here:
DesCoolVolFlowMin = max(DesCoolMinAirFlow,
DesCoolMinAirFlow2,
DesCoolVolFlow * thisTUFZSizing.DesCoolMinAirFlowFrac);
and here:
// set the zone minimum cooling supply air flow rate. This will be used for autosizing VAV terminal unit
// minimum flow rates (comment seems incorrect, really used as a minimum lower limit for the maximum air flow)
FinalZoneSizing(CtrlZoneNum).DesCoolVolFlowMin =
max(FinalZoneSizing(CtrlZoneNum).DesCoolMinAirFlow,
FinalZoneSizing(CtrlZoneNum).DesCoolMinAirFlow2,
FinalZoneSizing(CtrlZoneNum).DesCoolVolFlow * `FinalZoneSizing(CtrlZoneNum).DesCoolMinAirFlowFrac`);
Don't worry too much about what this code does, more importantly that input is used to limit the cooling minimum flow rate during the sizing procedure.
Asked: 2018-09-28 00:17:32 -0500
Seen: 241 times
Last updated: Oct 04 '18
