In my unprofessional opinion, I would say: probably, but it might be pushing it a little. I've been able to get mine down into the mid 40's when I was first playing with it, but manually sutstaining it with ice water would have been a chore. I would suspect it would be a chore for the freezer to keep up too. It would ultimately come down to how fast your freezer could suck the heat out of your glycol holding tank, how big of a tank you could cram into the freezer, how much colder than 45 you can get the freezer down to, how much heat your fermentation is producing, and how well it is all insulated. You might consider a second radiator in the freezer to give the glycol some more cold surface area before it mixes back in with the main tank.... Might help slow down the warming of your tank if the freezer radiator is big enough.
Take all of that with a grain of salt though... I pretty much built mine without knowing what I was doing and just hoping that it would work. I know there are some folks on the board here who have the mental capacity and expertise to run through the calculations, so if you get a reply that seems like they know what they're talking about, I would take their word over mine!
I bought one of these "things" (still not 100% sure what it originally was) a month or two ago... Got it all taken apart and down to just a nice little compressor/condensor and cooling coil. I've kinda put it on the back burner for now, but I'm eventually going to find a way to add it to the Fermoire to at least assist with keeping things in the "ice chamber" cooler.... Either directly on the bucket o' cooling water, or maybe just air-cooling the chamber to help draw off the heat that the water brings back down into it. For $20, it was too hard to pass up.
Since you're still in the what-if stage, you might see if something like that might fit into your plans!
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Good luck!
Many thanks BerserkerBrew!