After picking up a chest freezer from Craigslist for $50 I got it home only to have it die the next day.  After staring at it for about 6 months I read some of the fermentation chillers that were built using glycol baths chilled by freezers, or AC units.  Remembering I have a working fridge with a freezer an idea was born.  So after some parts and pieces and a days worth of work I had a working fermentation chiller and no longer had a useless dead chest freezer.

From Summit racing I got a frame rail mounted Transmission cooler and from All Electronics I got a set of fans for a server.  These normally run on 12V, but at the voltage they scream.  I am running them in pairs of 4 at 5.6V.  At this voltage they work great.

The cooler is mounted on the end of the chest freezer with the hoses passing thru the back.

I mounted pieces of plexiglass to the top and bottom to control airflow.  The fans are mounted on the bottom and pull air thru the cooler and blow it down against the bottom.

My digital controller is hooked to a power strip that the power supplies for the fans are plugged into.  The thermistor from the controller is mounted in the middle of the back wall of the chest freezer.

In the freezer there is a rubbermaid tub with glycol in it.  In the glycol is a small fountain pump from Lowes.  The glycol passes from the tub thru the cooler in the chest freezer, then back into the freezer where it passes thru a 10' length of copper tubing then back into the tub.  The copper tubing helps dissipate the heat in the freezer.

The fountain pump runs all the time, as I found it would freeze up otherwise.

Initial test runs showed I could easily maintain temps down to 60degrees even in my hot garage in the middle of the hot Southern California Desert.