Boy oh boy, what a journey this has been and I'm just now able to respond to this thread! Let me see if I can answer your questions and provide further details.
So, when I originally started this project, I scoured many home brew setups across the internet and used them as reference. When I thought about the wasted space around the staircase and how it was useless (for much anything else), I interpreted that as "just a little space" so it would work, but my mistake was not figuring in volume. The fridge is 4.6 cu ft and the total volume space post installation was 40 cu ft. Okay, so I took the following comment and began experimenting.
So, I did some very basic calculations on the cubic feet numbers you provided and if your numbers are correct, and I understand those numbers, and my math is correct, you’re asking a refrigeration unit that was designed to cool a 4.6 cubic foot chamber to cool a chamber that’s 20 times larger. That’s a major chore indeed! This may be part of the reason why the temperature only dropped 1° in 12 hours.
I began to wall off each chamber progressively shrinking the volume to see what size the fridge could handle. I am now down to about 10 cu ft, which according to a couple other builds out there, should work. In the following image, you will notice the temp control sensor (hanging black wire). I was able to achieve 47.5° even with frosting/icing on the freezer shelf.
In regards to kellerbrauer's comment about vapor barrier, would aluminum sheathing and rubber door gasket resolve this issue? I referenced this build how-to ( https://bit.ly/2kgKJPE
) as a basis for my project. It appears he has a pretty simple door/frame seal without such seal.
You asked where the fan was located and how it was utilized, here are a couple of pictures.
So now that I had achieved a sufficiently(?) cold temp for the kegerator, I now wanted to suck some of that cold air up into the fermentor which would sit at 68°. Fan installed. Temporary duct work installed. Insulation installed. What is confusing me is after flipping on the fan, the upper chamber increases 2° in about one hour, which is why I added the insulation as I thought the heat was coming from the chamber with the ducting. Even with the insulation, it didn't help, so the heat has got to becoming from the little motor, but I figured the air moving acrossed it would keep it from heating up. Actually, I didn't think this fan motor would ever be a heat issue!
I'm going to stop this reply here and see what your initial comments are and I'll get your more info as needed.
Thanks for everyone time and helpful input.
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