This is not a new idea and has been discussed in some depth on other forums. The major problem is condensation just ask the huge number of people that have carried out this mod.
This thread refers to putting a motherboard in a fridge, the forum i refer to mentions this all the way up to small compressors, condensers, evaporators, you name it they did it.
You should also be aware of the dangerous gases and pressures in most types of refrigeration equipment.