Hey, I am trying to model my building with only exhaust fans in each thermal zone. The supply air is provided through openings in the window frames. My building consists of one central ventilation unit which takes the the exhaust air out in each of the zones (50 zones in total). To do so, I am adding the ZONE EXHAUST FAN from the library to the zone equipment under the thermal zone tab. I have defined the fan efficiency, the maximum flow rate, the flow fraction schedule, and the balanced exhaust fraction schedule (always 1 since the supply air is provided by infiltration). But when I run the simulation now, I get no consumption for the fans.

So my question is now if I have to define an Air Loop under the HVAC system tab too? And if yes could you please tell me how to do this for this specific case! Thank you!