So basically the thing is an old chest freezer my parents were looking to get rid of so I took it off their hands at the cost of moving the damn thing. now a chest freezer is a nice option because of the size and layout. I can have up to about 5-6 fermentations going on at once but when it does chill there is a lot of condensation that builds up and this can create a mold problem. I would suggest finding a mini fridge that would fit you fermentation vessels. I got super lucky with that part of the build. these things are generally pretty spendy new especially at the size of mine. however they frequently turn up on craigslist in all shapes and sizes. sometimes at the cost of moving them. so the freezer is obviously what makes the fermentation chill. it's all controlled by a little temperature controller unit I half built. you buy the controller off ebay from china for super cheap and wire it up to an outlet to control devices depending on whether the fermentation is too hot or too cold. the temperature is measured by a little probe connected to the controller. the other end is insulated against one of my fermentation vessels. you want to measure the temperature of the fermentation not the ambient temperature. so I just put some sheathing on one side and taped it to the side of my carboy.
so here is the fridge itself. obviously more storage space for all your shit. you can see I have one batch going at the moment. in the upper right corner that little black box is my heater so I can heat things as well. I currently have a saison fermenting at 80*.
This is the little controller. top outlet powers heater and bottom one controllers freezer. you can see it's in celcius but it was worth it for the price. Here is a pretty good build thread for the controller.
http://www.homebrewtalk.com/f51/ebay-fish-tank-controller-build-using-wal-mart-parts-261506/ The ebay controller is called the STC-1000 and be careful when buying it. some are sold for 220v and you dont want that. some also just have one control instead of one for heating and one for cooling. which you may want instead.
here is a pic of the probe. its inside that pink foam right up against the side of the carboy.
this is my little wal mart space heater and computer fan. space heater provides heat and computer fan circulates air to cut down on moisture and to keep temps uniform.
if you guys have any questions on the build feel free to send my a pm or just ask them here.
