Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
look into https://bigladdersoftware.com/epx/docs/9-5/module-developer/branches-connectors-and-nodes.html.
It looks to me like you need a Splitter (Connector) object right after the Fan and before the Cooling Coil that splits the airflow driven by the single fan through the Branch with the clg, htg, and aux coil and the furnace Branch, and a Mixer (Connector) object right after the Aux heating coil that combines the flows from the furnace and coil branches. In terms of the IDF, you would specify the geometry of the loops with correct node assignments.
Per the documentation, "Nodes connect components along a branch: the outlet node of one component is the inlet node of the next downstream component."
The DualDuctAir example shows a configuration for one duct branch with heating and one duct branch with cooling. You want one branch with the coils and one branch with the furnace. Not sure if a DualDuctAir system is right for that configuration, but I hope this helps get you started.
