Originally Posted by barryfine
The only circulation I have is from the natural convection of cool air falling and warm air rising. If I have issues down the road I'll consider adjusting my design, but it appears to be working so far. I've looked at a number of different fermentation chamber builds and didn't really notice anyone doing what you're talking about.
Every one I've seen has circulation paths. They might not be obvious, but they are there.
Yes, natural convection will move the air around inside the chamber, that's not the issue. What you want to accomplish is to move
the cold air from the fridge over to the chamber and return
the warm air from the chamber back to the fridge. You need an in and an out path to accomplish this. It's a bit like putting your mouth on a plastic soda bottle and trying to blow into it - w/o a path for the air to escape, you don't really get any air movement. But put a hole in the other end, and the air moves right through.
It might be working because you get some initial movement and air flowing through leaks and some back through the fan once the pressures equalize. But I bet it runs out of 'gas' when it's more fully loaded, or the fridge might be called on to run too much (probably not, I just don't think you'll get enough air drawn away from the fridge).
Here's a thread with links to a classic design, the baffles, fan on one side, and port on the other provide the 'flow through' circulation.http://www.homebrewtalk.com/f39/son-...0/#post1067070
Here's a simple approach - remove (or reverse) one of those two fans. Then add the tubing from that fan (or hole) to go down to the bottom of the chamber. That will force air movement through the chamber and back to the fridge. I really do think your results will be rather marginal w/o full circulation. It looks like a really nice build, I'd just like to see you get the most out of it.