Extract fan on double skin facade

[sabrinabarbosa]

Hi all,

I have been modelling and simulating building models with double skin facade and I am currently trying to apply an extract fan into the double skin façade cavity.

I have divided the cavity into several vertical thermal zones and connected them by holes.

So I applied an EXTRACT FAN on the top thermal zone. It seems to have some effect on the air temperature in this zone but no effect on the lowest zones of the cavity. In a real building, the air extracted on the top level would increase the ventilation and have some effect on the temperature on the whole cavity and on the rooms connected to the cavity by windows.
Does anyone knows how to make the extract fan have some effect on the whole cavity and rooms?
Thanks

S.