Looks like the Cost per R value (SV THIRD DAY) is a good Guide! Thanks!
I built a Prototype refrigeration
system and am now looking at Aerogel or VIPs to get the thickness down, while keeping the system efficient.
Pic attached: Partially built, a box in a box with an extra "Bread Box" on top to keep the sun off everything.
prototype is of R-5x1"panels "wall insulation", not Polyiso.
Thickness is 4" to 8". The thinner being in "front" where people need to reach over and past the insulation for access. This and the lid/hatch are of best ROI for Aerogel.
The BD35 is SP water
2351. Yes, boat
movement helps efficiency noticeably)
power is 250W. (LEDs lighting)
is 12v x 225AH (plus a starter 12v batt)
The whole yacht's usage recharges on a typical day by 2pm latest, allowing for desalination work thereafter (Spectra 200C 7amps makes 8gallons per hr)
The prototype runs about 14Ahr overnight (tough to isolate like a Lab, with the sun rising) Ambient is about 75F day, 62F nights.
It has FOUR sections:
where the evaporator is. 15-25F Thermostat is above the evaporator, in contact)
2) Below that is 1/2Cft freezer storage
. Blue-Ice filled-in; 20-30F
3) After 1" of R-5, there is the refrigeration
area. 38-55F (usually lined with beer
4) Above all this, 4" of R-5 away is a "Bread Box" to keep the window's heat off the fridge. always below 65F.
a 4-ch temp monitor
(by Perfect Prime, AMAZON) shows the temps as stated above.
I've Cruized this setup for several weeks throughout the Channel Islands, CA this summer full time and it works well. Yes the fridge area is a bit warm when 55F. One goal was to fast freeze fish
in the evaporator, then store that below in the 'freezer storage'; which works well. The Bread Box was almost a joke when built since the boat
shape just kinda dictated it. But this too has been great, since handmade bread keeps longer, 4 days+ and is good for soft butter too (yum)
The final version will be built inside-out; tech first, wood finish last.
The HighTEch isulation ($$) will be at LEAST for the front, top, and hatch
I'll fibreglass the whole thing, no drain, inside for a water-tight tub.
I'll cast in-place with FRP, 404 filler, and an 1/8" freezer seal with hardware
Finish Carpentry is my weak spot, and awful expensive....thats another Thread, LoL!
Thanks for your expert advice SV Third Day and All!!