View Full Version : How about a 3-way

09-29-2010, 10:28 AM
Does anyone have experience with a 3-way RV type refrigerators? (120V AC, 12V DC and propane.) If so please do tell.

I just picked up a nearly new Dometic mini-frige for $25, too good of a deal to pass up. These things are so weird to me, they use heat to make cold.

The plan is to pre-cool it on 120V AC at home prior to heading out, use 12V dc on the road then use propane while in camp (I don't think its safe or legal to use propane while on the road). I want to drag this out with me on expo trips. It doesn't have any moving parts, and was originally in a pop-up so my hope is they can tollerate bouncing around on a trail.

09-30-2010, 09:03 PM
No experience with the refrigerators. I think the title of the thread is scaring people away!!

09-30-2010, 09:41 PM
You seem to have most of it already. It should have a switch to go from one setting to the other, at least from electric to gas. Other than that, the propane is a heat exchanger, uses temperature differences to make cold. Like geothermal units.

09-30-2010, 10:23 PM
There are two switches on the back, one for 120v and the other for 12. There is also a push button to light the propane flame.

I did some reading on exeditionportal.com and they seem to frown on the three way fridges and go for the 2 way ones with the conpressor. I couldn't find anyone reporting a failure though.

10-05-2010, 03:31 PM
My good friend sells a bunch of them and wrote an article about the various options and pro's/cons.


I'm probably picking up the ARB version sometime soon. It's slowly moving up my list of things I want/need.

10-19-2010, 10:49 AM
Propane is used in many rvs for refrigeration. My grandfather had one in his trailer ove 40 years ago. Read the directions and have fun.

10-25-2010, 07:03 AM
Alway though propane fridges were cool.....never knew jack about them.

10-27-2010, 02:13 PM

A gas refrigerator uses ammonia as the coolant, and it uses water (http://science.howstuffworks.com/h2o.htm), ammonia and hydrogen gas to create a continuous cycle for the ammonia. The refrigerator has five main parts:

Generator - generates ammonia gas
Separator - separates ammonia gas from water
Condenser - where hot ammonia gas is cooled and condensed to create liquid ammonia
Evaporator - where liquid ammonia evaporates to create cold temperatures inside the refrigerator
Absorber - absorbs the ammonia gas in water
The cycle works like this:

Heat is applied to the generator. The heat comes from burning something like gas, propane or kerosene.
In the generator is a solution of ammonia and water. The heat raises the temperature of the solution to the boiling point of the ammonia.
The boiling solution flows to the separator. In the separator, the water separates from the ammonia gas.
The ammonia gas flows upward to the condenser. The condenser is composed of metal coils and fins that allow the ammonia gas to dissipate its heat and condense into a liquid.
The liquid ammonia makes its way to the evaporator, where it mixes with hydrogen gas and evaporates, producing cold temperatures inside the refrigerator.
The ammonia and hydrogen gases flow to the absorber. Here, the water that has collected in the separator is mixed with the ammonia and hydrogen gases.
The ammonia forms a solution with the water and releases the hydrogen gas, which flows back to the evaporator. The ammonia-and-water solution flows toward the generator to repeat the cycle.