Well, i wanted to avoid reading for hours, i was hoping that everyone elses reading for hours could provide me a shortcut.
We have read for hours. And each of us have taken different things away from that research. My idea of a fermentation chamber is 7' tall, 5' wide, and 3' deep. Some thing I'm nuts - And their ideas, based on their research, are better for them. We don't know what model fridge you have, or how big of a chamber you want to build. Do you want to lager in it? Or just ferment ales? Just carboys? Or Carboys, maybe cornys or a conical?
There are WAY too many variables for anyone here to answer your question in any more detail than the following:
You can probably use your fridge for cooling - Depends on how much cooling power it has, and how big your chamber will be...
You can build the walls out of just about anything - Most use some sort of frame and plywood for sheathing... (One even used a kitchen table)
You can insulate with about 1/2 dozen different kinds of foam or fiberglass - Most use extruded foam insulation with great success... (The pink stuff - Formular I think)
You can use a Love controller, or Auber Instruments PID, or a Johnson or Ranco to control the temperature. Some use a BCS-460 or BrewTroller. As for wiring them - Research. There are a ton of great threads that will walk you through every step of every step of your project.
If I was to venture you a shortcut, it's "Build a box on the end of your fridge. You should probably insulate it, and you'll want some sort of temperature controller to hold fermentation temps.
Good luck
Ok, I'll STFU (Been drinking a bit tonight) and search for ya for 10 minutes, but that's all you get
The first link is a "Son of" a fermentation chamber, modified to use a dorm fridge - It's also the first thread I found when I searched for "Fermentation Chamber" :rockin:
https://www.homebrewtalk.com/f51/fermistat-bastard-fermentation-chamber-161146/
https://www.homebrewtalk.com/f51/my-fermentation-chamber-kegerator-build-102383
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https://www.homebrewtalk.com/f51/another-fermentation-chamber-143443/
This one has a great idea from Fatman, and the plan I have percolating in my little brain...