[H/V Vega]

Good day all,
I have been following this thread for some time now and at last here I am hat in hand to see if I can find some assistance. Vega works with WHO supported programs to provide help with child immunization and other public health programs for developing island nations. That means we need dependable freezers and cold boxes to carry medical supplies often for months at a time. Right now we are refitting our cold boxes and can use all the help available on what and how to get the most dependable and energy efficient systems. The three boxes average about 130 liters each and are all side by side in the same construction. The insulation is 6" at the bottom and an average of 4" around the sides ( back and one side is 6") there is 4" between each box. I like the idea of the Stirling units but can't seem to get an answer out of them. That seems to leave the old Danfoss compressor route as the only one on offer. Any ideas? I would prefer not to use water cooled as the waters we work in are warm and full of life that tends to block strainers and pipes quite often. Any chance we could convert our existing house hold 220VAC deep freezers to this application? Not the best I know but at least available. Thanks in advance for the help.