Tackling a Mother of Fermentation Chiller

I am currently undergoing the project of building a fermentation chiller. I am building the 38dd Mother of Fermentation chiller. I have my foam box built and glued and am about to seal it with silicon caulk, and build the ice compartment at the bottom. But I was wondering from anyone who has built one of these which direction do I blow the fan? Should it blow up through the tube on the back corner or blow through the ice chamber to the holes on the front poor of the chamber?

I had mine blow back into the fermentation chamber. Its been 80 + in the garage and 65 in there. I have two one gallon jugs I change out once a day, they are usually 60% frozen.

You want to have the fan suck air from the top, down through the corner passageway, over the ice, then back up into the main room. This is because hot air always rises. If you did it the other way then the cold air would get pushed out the top, fall to the bottom, and then get sucked back through the ice again. This causes a slightly warmer pocket of air to linger around the top.

Either way is going to work, and that slightly warm pocket of air would hardly be noticeable if you were in there with it, but you will cool the entire chamber faster and more evenly if you channel the hot air on top down and then over the ice.

I actually just posted pictures last night of the one I built, let me know if you have any questions, I'd be happy to help in any way I can.

https://www.homebrewtalk.com/f51/brotha-anotha-motha-fermentation-chamber-411004/

Awesome! Thanks everyone, your input verifies my initial understanding but I guess I was just over thinking it. I won't be able to get much work done on it this week but am excited to finish this up, and get a lock on my ferm temps. Will post pics of the finished project! Thanks again!!