It is very common here for produce growers to build a super insulated room with an airlock entry then run 2 or 3 window air conditioners to pull it down to a steady cold temp. Like a poor mans DIY walk in cooler.
No clue on costs to run but dead simple and easy. You can buy window AC units lots of places at least here.
Personally, if I needed cold storage in volume thats what I would do. Research efficient AC units. Size the room to the needs and have all space filled with thermal mass like tubs of water your wine, whatever.
A smart guy could probably make that work well at least after the initial marathon run chilling it all the first pass.
The last AC window unit I bought was only $75 or something so thats lots cheaper than wearing out the freezer.
Just my theory.
I have other ideas, too but anyone with enough wine to be "valuable" should quit being cheap about protecting it and bite the bullet, cough up some cash and get it done. Or not.
Tom
"Education consists mainly of what we have unlearned."--Mark Twain
