This is a thermo-electric chip (TEC) with an air cooled copper heat sink salvaged from a computer on top and a length of 1.5" copper pipe filled with antifreeze on the bottom. It is stuck together with thermal epoxy.

It is about 65 degrees in my shop.

The "hot" air that passes the cooling fins is about 75-77 degrees. The fan is .27 amps and moves a lot of air. I tried a quieter fan, but it didn't cool the hot side of the TEC as effectively, which is the key to getting the maximum cooling efficiency from a TEC.

The cold side of the chip quickly cools the copper pipe.

Because the bottom of the pipe is filled with antifreeze for thermal mass, it cools more slowly.

In order to get a better understanding of the cooling potential, I put it in a beer cozy and wrapped a dish towel around it to insulate the copper pipe. (The fan next to it is heat operated and is the opposite of the cooling process that I am using.) It is 10:43 and I am starting out at 65 degrees.

By 11:03 I have frost at the top of the copper tube. The towel actually froze to the copper pipe, so I'll have to keep produce away from it when the cooler is complete.

In an hour, I have frost over the entire exterior of the copper tube. Surprisingly, the copper pipe could frost when the antifreeze seemed to be at about 45 degrees. A couple more hours (at 3.5 amp hours) would likely get the entire thermal mass below freezing. My antifreeze mixture freezes below -25F, so I don't think that I need to worry about bursting the copper pipe.

This will be the insulated container for the TEC. I'm gluing it together with foam. It is 1.5" foam board that comes in a 2x8' piece. If I think I need more insulation, I will simply make another exterior layer from the left over piece. It is small, but then so is my boat.

The foam cures to a stage that is similar to a roasted marshmallow when cooling. At a certain point it is still in a plastic state, but not sticky on the exterior. Any areas that were over filled can be pushed into a fillet using a finger.

I wrapped some duct tape around the foam box for a little abrasion protection (I used up a couple of partial rolls, hence the multi-colored box). The TEC unit sits in a hole cut in the lid.

When not in use, the TEC unit fits inside, a foam plug is put in the TEC hole, and the entire box fits under the splash well. *