First off this is a great project. I am really tempted to build it.
Someone made a comment about using a fridge. I have to agree on a couple aspects and want to share a few thoughts on others:
Space: either you have the space or you don't but I don't see why a person couldn't re-purpose their small Sanyo kegerator for fermenting. Or just buy a small used upright freezer or small chest freezer. Leave it out on the back porch or balcony if you don't have a garage or basement.
Spouse: I have a deal with my wife, I get to ferment in the upright freezer for my lagers: 2 October Fests, my Christmas Beer and a Vienna. The rest of the year she gets the stand up back. It is a simple matter of unplugging my temp controller.
Energy: There can be no way you're "saving" any energy with this GREAT little fermentation chamber. You still have to freeze the water to get the ice. You either buy it (about $1.50 a bag these days) or you freeze it yourself. Either way your paying to remove all the heat from the water to make the ice then using the ice to remove the heat from your fermenter. You may be using the same amount of energy, but you are probably using more than just getting an old fridge.
This is a super cool project. I think I'm going to make one for all the ales I ferment the rest of the year when I am not using the upright for lagers.
