Do I need a HVAC System for RoomAirNodes (Mundt Model)?

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Hello,

I tried to simulate a Doubleskin-Facade with RoomAirNodes in EnergyPlus 8.9.0.

I got an error report "Zones must be controlled for Mundt air model. No system serves zone DSF". Solving this error is only possible to add a hvac system? My Doubleskin-cavity has no internal loads or hvac system. It is controlled about natural ventilation.

Thank you for your help in this matter.

Marco