I must say, the choice of old school ice box tech with a modern control system is an interesting mash up- almost steam punk if you use some exposed mechanical actuators for doors an such.My current plans involve 5 sensors in the chamber to run the controls, plus a sensor in my ice chamber and one on the outside of the entire chamber for data logging. I don't have the parts I need for a thermowell, and I'll be filling my conical tomorrow, so that'll have to wait for a few weeks until the IPA is done dry hopping
I only bring this up because you seem to be interested in very fine temp control- using a single thermowell to control temp in a ferm vessel, conical or otherwise, can result in radial stratification during later stages, unless the location is almost ideal. From other threads, that location is very close to the wall, and about mid-way on height, but that location is variable, especially depending on how it is chilled- air, jacket(s), immersed coil, etc.
Also, controlling the vessel temp without using the actual vessel temp in the control loop borders on the impossible. This method is difficult even with passive objects if the air temp sensor is not close to the vessel.
Are you planning on have one large chamber, or multiple small ones with separate fans? I ask because it is impossible to control multiple active ferments in one chamber with only one control input. More precisely, to control n fermenters, you would need at least n+1 control inputs. If you could guarantee one vessel would always generate more heat than all others, you would only need n inputs.
A real world example is a guy who uses a single fridge and 4 heat wraps to control 4 fermenters. The fridge is set to a temp low enough to keep any active ferment in check.
The elephant in the room is why you sprang for a conical, and don't drop some coin (<$50 or free) for a Craig's list fridge to put it in, or at least use as a cooling source.
When people talk about building chambers, I always think of this thread:
https://www.homebrewtalk.com/f51/fu...lled-fermentation-chamber-about-200-a-175456/
The punch line is here:
https://www.homebrewtalk.com/f51/fu...ation-chamber-about-200-a-175456/#post2616114
But what is even funnier, is that the thread continues with people asking all kinds of questions about how to do it.