doubt gap or opening in the wall

edit

So I really want to let some EnergyPlus experts chime in, but I'll give some background and offer some suggestions. I assume you want to model the area between the two walls in front as a thermal zone.

1. If you model the opening with window you will get daylight through the opening but not air
2. You could model the wall in front as shading surfaces, but then it is only being used to shade the wall behind it. The space between the walls wouldn't be part of a thermal zone.
3. I'm not exactly sure what would happen if you don't fully enclose the front thermal zone, but I don't think that is what you want to do.
4. Back to item 1. If you modeled the opening as a window, you could try to set a very high infiltration for that zone, to mimic the air exchange that would normally occur.
5. The Wind and Stack object in EnergyPlus might be a good solution, but it does have limitations. OpenStudio doesn't currently support this so you would have to add this as an EnergyPlus measure, or manually extend the IDF file to add this.
6. Lastly, you may want to look at the Trombe Wall documentation. You could model this as a naturally ventilated trombe wall. Again, this is something not directly supported in OpenStudio, so you would need to create an EnergyPlus measure or edit an exported IDF file.