Originally Posted by bstreep
Our refrig/freezer (separate) are both water cooled. There's no contest here - you dump that heat into the water instead of into your boat. Water is WAY more efficient at cooling than air.
Water is definitely a more efficient medium for heat transfer however, water also requires significantly
more energy to circulate. I went through this process looking for the most energy efficient refrigeration
system I could find. According to both Richard Kollman and Nigel Calder, 12V air-cooled compressor systems are fine for smaller, well insulated fridge boxes - even in the tropics.
That being said, when I designed my 4.6 cu.ft. fridge box, I talked to the owner at Sea Frost about whether to go with the BD35 or the BD50. He said I was right on the dividing line and that either compressor would probably work fine. He did say the energy usage would be just about the same regardless of compressor. I took him at his word, especially considering the price
difference between the two units was negligible.
Just a thought - might want to consider a BD50 unit. It will cost marginally more but will have the reserve capacity for cold tropical beer
on really hot tropical days...