Dual refer system Frigoboat & Grunert

[dougshipl]

We're installing a Frigoboat k50, keel cooled,12volt refer and freezer system supported by our house bank batteries. Our current system is a Grunert engine supported system, which works ok but it's a hassle to run engine everyday for a few hrs to maintain cold box temps. We are thinking it may be best to just leave the engine driven Grunert system in place and instal the Frigoboat separately, mounting the Frigoboat evap. plates just below the Grunert evap plates so that we have the old Grunert system as a back up system on lengthy passages, if needed. Has anyone done this? Aside from taking up space and added weight does anyone see an issue with this?

All thoughts appreciated. Thank you.
DS

[celenoglu]

I have seen similiar installations on different boats. The engine driven unit operates at a lower temparature so when then the engine is running, it cools the box a few degrees below the 12V unit and the electrical one does not work. ıf the engine is not running the electrical unit works.

[dougshipl]

Thanks Celenoglu

[Capt Len]

If you run the engine driven compessor to a eutectic fluid plate . cold will last for days before the electric one comes on.I draw freezer down to -30 and days later still rock solid. It's called latent heat of phase change or something like that.

[dougshipl]

Thanks Capt. I was considering leaving the engine supported Grunert cold plate in place and mounting the Frigoboat thin, 10"x40", evap plate right below it...so the systems would be truely independent. The box is about 7sq ft