So after some last minute tweaking and fiddling, the project seems to be working as designed. Lots of details to tweak on when and how fans and valves are controlled and maybe it shouldn't keep the same constant temperature overnight and during the weekends, but as a proof-of-concept it seems fine.

Switching the entire section from heating to cooling and vice versa using the wireless switch module works as intended, and as one can see in the above image (both Großraum 3 graphs), a constant temperature is being maintained in this section of the office (open office plan) with just 3 out of the 13 FCUs under its control.

Also in the image are the two sensors on my desk (obviously), and a sensor in a meeting room (MemoryLeak). It's interesting to compare my own creation with the old system as installed in a properly sized room. Seems fairly similar, but perhaps less aggressive due to the smaller thermal feedback loop for my system.

Today I started releasing the software for the project (https://github.com/MayaPosch/BMaC), with the hardware designs (KiCad projects) to follow soon.