[MOD] Powerless Fridge

[Yennoth]

Hey everyone,
I'm currently trying to make a powerless fridge, basically a shelf that would keep item frozen in it, I've tried many things but I can't find anything that works, I either need power or walls around it.
Would you guys have any idea on how to do it ?
(I have very limited knowledge on C# and basically just try to understand how things work and then copy the parts that make it work)
Thanks for reading that and have a great day !