This is my fermentation fridge. I have a temperature controller that keeps it at the temp I set. But the fridge can only cool, not heat. I don't heat my office kitchen at night and it was 40 last night. So an electric blanket on low will make sure the temp stays up at 63. If it gets warmer, then the fridge will kick on and cool it down. Works great especially when its 25 outside.
Carboy into the fridge. You can see the temperature probe wire from my controller. I put the probe up against the carboy so that is the temp it is reading. In the back, you can see a small plastic container. This is my blowoff bucket. It is filled with sanitizing solution and the tube coming from the top of the carboy cap goes into this solution. When the yeast starts working, it will spit out through this tube as a way to relieve the pressure in the carboy.