displacement ventilation in Energyplus get strange result

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this is also my first time trying displacement ventilation, i can run the file and get the results. I tried 2 situations, one with DV and one without DV. The room places in interzone of the building and has almost whole year cooling demand. But the energy demand with DV has no advantage as the mixed one, this is not fit for my understanding of DV. Shoud I give a smaller ventilation demand for outside air to the DV model? I was wondering a result with smaller energy consumption for DV with same values for other settings.

How can i upload the idf files here? Thanks

RoomAirModelType, MOD1, !- Room-Air Model Name hall, !- Zone Name ThreeNodeDisplacementVentilation, !- Room-Air Modeling Type Direct; !- Air Temperature Coupling Strategy

RoomAirSettings:ThreeNodeDisplacementVentilation, hall, !- Zone Name SchDV, !- Gain Distribution Schedule Name 1, !- Number of Plumes per Occupant 1.2, !- Thermostat Height 1.2, !- Comfort Height 0.1; !- Temp. Difference Threshold for Displacement Ventilation

Schedule:Constant, SchDV, !- Name Fractional, !- Schedule Type Limits Name 0.9; !- Hourly Value