Hi all,

I´m running into some complications to model a passive space that pre-heats the fresh air coming into several offices - hopefully someone can through some light on this.

I´m modelling an office building with a central unconditioned space (like a wintergarden). The office fresh air is taken from this wintergarden (so that the sun will pre-heat it in winter). A quick sketch of the scheme:

The natural ventilation of the wintergarden is modelled using the Air flow network (there is an HVAC defined for this zone, with no fresh air intake and heating/cooling setpoints set at -100/100ºC), and the Offices HVAC is set as ZoneHVAC:IdealLoadsAirSystem. Each HVAC system is defined with a supply and exhaust air node.

At first I set the Outdoor Air Inlet Node Name of one Office zones as the exhaust node of the wintergarden, and that actually worked. The problem comes when the two Office zones need to draw air from the wintergarden, as EnergyPlus complains that one Node (The wintergarden exhaust air node) cannot be defined twice.

So far, I´ve tried creating a AirLoopHVAC:ZoneSplitter, to divide the wintergarden exhaust node into several nodes, that I can define in the Outdoor Air Inlet Node Name of each ZoneHVAC:IdealLoadsAirSystem. Unfortunately, my experience modelling HVAC connections is rather limited, and I ran into all sort of errors regarding air supply paths, duplicate node names, etc.

Does anyone have experience on something similar? Many thanks in advance!

Rafael