Yep my default FC is a fridge, but my glycol rig allows me to run multiple independent fermentations in a smaller space than having three or four fridges.You can use one of these FermZilla Conical jackets:
https://www.kegland.com.au/jacket-for-27l-fermzilla.html
The only issue is they are slightly bigger so you end up with some dead space in the jacket but they work OK.
I know it's a bit jump up in cost but you really cant just putting the whole thing into a fridge. We will have these in a few months but you could make your own with a second hand fridge and a temp controller:
https://www.kegland.com.au/rapt-temperature-controlled-fermentation-chamber-fridge.html