I have a shelf that I insulted using sheet rock and spray foam I had laying around and 4mm Plexi-Glass doors.
Its aprox. 1300mm * 400mm* 450mm (Holds 85 beer) . I am only trying to stabilise the temperature not make a fridge.

The plan is to adapt a PC water cooling system to the shelf in addition to a Peltier plate.

So far:

*The shelf is what is.

*I have drilled a 75mm hole in the side. This is where the electronics will meet the plumbing with a plug I printed.