Adding Circulation Fan to Refrigerator Box

[Sailing Drummer]

I don’t have the answer to your question but I can tell you what and why I did my setup. My setup is similar to what you are planning - cold air from the bottom of the freezer to the refrigerator, and then back to the freezer from the warm side of the refrigerator through a pipe going to the top of the wall between them.

I bought an inexpensive controller to power the fan. I set it to turn on and off at the temps I wanted the for the warm side of the refrigerator. My reasoning was I wanted the refrigerator to stay at a fairly controlled temp range. I have it set to go on if it’s above 38°f and to go off when it reaches 37°f. This keeps the frig at good temperatures throughout the entire box and it gives me the ability to arrange items based on how cold I want them. The cold side of the fridge is a few degrees colder. The only thing that give the frig it’s cold air is the freezer air circulating between the 2 holes in the wall between them. I have the cold plate temp set to go on at -2°f and off at -3°f. I know that this difference is not what is normally recommended, but it works better than any of the various settings i previously had and I’m happy with it.

The change in amps used has been negligible. The change in the refer and freezer has been having a much more consistent temp in both.

Also, both before and after I put the fan between the 2 boxes I still have times when the temps are higher due to adding more food and leaving the lid open too long when I do that.

Generally, if it’s not horribly hot in the cabin, I use about 35-40 amps overnight from the freezer. During the day I don’t check my usage, except to check to make sure I’m getting enough power from my solar to get me back to the batteries being charged up before sundown. I only have solar and engine for charging, no shore power - we’re almost never at a dock.

I hope that info helps.

[sailorboy1]

Originally Posted by krid2000

I'm currently planning to install a circulation fan & hose contraption in my fridge, sucking cold air under the evaporator to the other side & top of the fridge. I'm trying to decide if I should run the fan only when the compressor is running (= 1 new wire to install) or always (2 new wires). My compressor runs about 25-30% of the time.

Does anyone have comparative data between both scenarios regarding energy savings and/or heat distribution? Does always-on make a significant difference?

Thanks
Dirk

I started this thread years ago so....

I installed a separate fan plus later wired the evporator fan to run all the time. Those fans use about .25a so the extra power use is pretty meaningless and it keeps the box temp more even and the only time I have ever had to defrost is when I put something in the box that blocked the fan.

[krid2000]

Ok, it sounds like the two upsides are a more even temperature distribution and less frosting over, not so much the energy savings. I think I'll just install that small hose & fan to run continuously and just see what happens.