The conical fermenter project is coming along well. Here is what's left to do:
1. Mount stainless cooling coil (chiller) to bottom of lid so that I can quickly chill the hot wort after boiling.
2. Make a silicone seal for the lid
3. Make some beer! Wow, I can't believe this project is almost done... it's taken a long time.
Here's a picture of the lid with a thermowell that I made. The thermowell allows a temperature probe to be inserted deep into the tank without exposing the tank to the outside air. It's basically just a long stainless tube that is welded to the underside of the lid and sealed (welded) on the end.
The peltier heating/cooling module is working pretty well despite the copper block soldering mishap. The thermal conductivity is not nearly as good as it should be, but it still seems to work well enough. My original plan was to use two separate peltier modules, but so far, one seems to be sufficient. Without any insulation on the tank, the device held a 15*F difference from ambient temperature, so this project may not even need much insulation.
The temperature setpoint is 67*F. For actual beer brewing, I'm thinking 64*F will be the target ale brewing temperature. So far, I am just using proportional control with a very high proportional constant. The tank has so much volume, and the heating/cooling power of the peltier is relatively tiny, so there isn't much tendency to oscillate.