This model represents an non-air tight zone. I.e. the zone air volume is internally fixed to a constant pressure and the sum of the air injected through the two fluid ports is consequently injected in the environment (as if all windows are opened). If a net mass flow rate leaves the zone, then air is extracted from the environment with the ambient temperature and humidity.
prescribesPressure
that indicates
whether this model prescribes the zone air pressure or not.
See #971.