Building a small fridge advice.

[bedouin]

I think the thermoelectric idea is a non-starter - firstly they are horrendously inefficient and secondly I think the cooling panel is actually a good conductor of heat so will let the cool box warm up quickly as soon as the power is disconnected. Compressor is the way to go.

Insulation is of course important - but 3-4 inches may be impractical - my portable fridge seems to manage on less than 1" but if I were doing it I would probably go for 2" celotex or equivalent

 

[PCUK]

To be honest, I use both. A compressor fridge for the food and a Supercool for the drinks which also takes overflow food from the fridge. I've never had a problem with excess current consumption and the Supercool unit brings the temperature down to lower than the normal temperature of the fridge. Certainly not to be discarded but perhaps not suited to everyone (like you lucky buggers cruising in Greece!)