I am trying to design

Question

I am trying to design a small 450mm x 600mm (ish)freezer to go in a confined space and concerned about getting rid of the heat generatted. Can the compresssor and working be put on the top of a unit enabling the heat to be lost through the top or do they have to be at the bottom. If so why i.e Gravity plays a part in the prosess. Do you have a freezer designers details