Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The fans are not operating at all, flow rate is zero for the entire year. The fan inlet node is the OutdoorAir:Mixer's relief/exhaust air node. Relief/exhaust air flow will always equal outdoor air flow (conservation of mass), and since no outdoor air is required for the data center, the outdoor air flow is zero and therefore relief air flow is zero. All of the data center's zone air is returned to the UnitaryHeatPump, none of it reaches the mixer's relief air node.
I think you may have better luck using ZoneMixing rather than trying to direct zone exhaust air through a fan into another airstream's return air plenum.
