I'm using your mod with Pyanodon's suite and the Enable Feature Flags mod (to enable spoilage without Space Age enabled), as plexpt mentioned in another topic.
I got an error along the lines of referencing "agricultural science pack" and "nil value" in 2.2.2.lua in the migrations folder. I changed the science pack to a different technology (logistics) to fix the error.

I love that your mod doesn't require Space Age! Every other fridge/freezer mod needs it enabled, which makes them not work with Py. If only there were more backported features, like the new enemies and weather...
I've tweaked your ingredients (basic circuits, batteries instead of uranium) and prereqs (just logistic science) to work earlier in the game, given how long Py progression takes (and because we already have logistics chests and started "refrigerating" using an item stacking mod that doesn't make apply spoilage to item stacks), but maybe only requiring chem science would be limiting enough for everything? I don't know much about vanilla balance, but I've got all the non-refrigerated versions of your items with only logistics science.

happy to hear that, this is designed not relay on any other mods to work, because I want to keep it simple. and clearly it did! there might be some left aways of "agricultural science pack" reference I haven't deleted. But technically it shouldn't, because I tested it with space-age mod turned off. so there is no "agricultural science pack" and if my mod still has references somewhere it should result an error and I can find it. but, anyways.

and if you have time, can you make a pr to the mod so I don't need to redo what you have done. I would love to have those ingredients tweaks so I can know what is suitable (I personally did not spend a lot of time on the ingredient design. so there might be impropriate settings), I can make it an adaptation to py mods, if lots of people use it. thanks

Unfortunately, I think I redownloaded your mod at some point while trying to figure out a desyncing issue my friend was having while playing co-op, so I no longer have the edited version. It was pretty simple, though-- I changed your science gating down to Logistics (which is already dozens if not over a hundred hours into Py, let alone Chem and Space) and replaced the higher-tier circuits with the basic type, electric motors to engines, and uranium fuel cells into batteries. My friend and I are making do by using Deadlock's Stacking Beltboxes to bundle perishables; these stacked versions don't spoil. Feels a little cheaty, but we still have to unstack things to use them, where I plan on experimenting more with your refrigerated inserters and fridges. If you want a feature wishlist-- maybe refrigerated belts and/or compatibility with Merged Chests? ^_^" Py also has Caravans that would be neat with freezing/refrigeration...

You could try visiting the Py Discord to discuss balancing with the devs and veterans there, if you're considering making an official patch/fork; they could help you come up with a much more elegant setup than mine.
https://discord.gg/tDjpUBM9
I believe they plan on adding their own spin on refrigeration when they release their Space Age expansion.