Trying to make this as short as possible.
In 1993, we met and befriended some chemistry PHD's turned cruisers who lived in Santa Barbara CA. They were not impressed with any of the holding plate "eutectic" solutions, as according to them none of the solutions actually phase changed over a tight temperature range. According to them, most just use proplyene glycol variations.
phase changes in a couple of degrees whereas antifreeze
in a car changes over a wide range.
Their idea was to invent a solution for a freezer
that changed like water, but at at zero f.
They did just that in their garage, and while going through all the patenting, licensing efforts etc. they had 55 gallon drums of the stuff taking up space.
Bottom line is, we purchased a holding tank's worth, used it on our Lord Nelson35 while in Mexico
Every morning around ten AM I manually kick started our 6 cubic foot fridge / freezer
which had a thermostat. It ran for around 3 1/2 hours drawing 17 amps and shut off automatically when the freezer got to -6f.
We had a top opening freezer of around 1.5 cu ft. and a front AND top opening fridge.
Even in the Mexico
heat, it never ran until the next morning when I'd kick start it usually reading +3f in the freezer.
During the installation
and construction of the water cooled Isotherm
/ holding plate system, I had to modify the electronic non programmable thermostat by changing resistor values which took forever. We made charts
of time vs. temperature until our heads were spinning.
When we were done with it all though, we had a cold water loop with a dispenser on the counter top for instant cold drink, lots of available ice too.
470 watts of solar
kept the whole boat in juice.
Just a few years ago, we checked in with them.
Their licensing never went through, and they said we could use it for our own if we wanted to.
boat is too small for a holding plate system so we never took them up on the offer.
Currently, we have a Vitrifrigo BD35 / keel cooler
which does nicely.