A eutectic refrigeration system uses a compressor/condensor just like a flat plate system, but used an evaporator coil immersed in a eutectic solution. The ES freezes and stores energy which it releases (well absorbs heat actually) when the compressor is off.
ES systems aren't any more efficient than flat plate systems for small DC powered compressors. Batteries can store energy as well or as cheap
as eutectic plates.
So using wind or solar
as your energy source to recharge your batteries, a simple flat plate system like Alder Barbour will work fine.
In the tropics with good insulation
, a 6 cu ft box will require 60-100 amphours per day of 12V DC power to keep cool. But solar panels
work good in the tropics as well. That 60-100 amphours can be produced by 200-300 watts of solar panels