A few years ago, a group of people had developed a system specifically for sailboats.
They had a website with pricing and a complete user manual.

Sounded great, but, it's not available anymore, I wonder what happened ?

Here is a link to the user manual:
http://www.fourwinds-ii.com/refrigeration/refrigeration_TropiKool40Specs.pdf

Here is a link to a beta testers experience (scroll down):
http://svhorizon.com/refit.html

Sounds like it was noisy, and performance was not much different from a regular compressor.