i've been thinking about it for years but i just havent had the time or money to invest into the research.

 

Any heat source will do. That flame is no bigger than a candle. You could even wrap an electric heat tape around the evaporator tube and power it with a small solar panel.

 

could you elaborate a little more on this please. i would like to try this.

thanks.

 

iif you do have one of those flame powered refridgerators that doesn't work try this.
take it out(pain in the a**)turn it upside down for 24 hours.this "burps it". I'm not sure what this does but it fixed mine.
the bad thing about the propane ones is their low cooling capacity.if you put something like a case of beer in one it takes a long time to cool it down.

 

I agree with Hick, the (usually propane) flame used to power these is very small, I'm sure a candle or oil lamp would suffice to run it.

I think what Hick was saying about the solar panel was to create a small electric heating element, powered by a solar panel. "Heat tape" is similar to the electric heating element used in electric blankets, water bed heaters, that sortof thing. It's a flexible wire you can wrap around the evaporator, plug it into a power source (i.e. solar panel) and it will heat whatever you have it wrapped around. Not sure if it would get hot enough though.

 

I found this at howstuffworks.com:

A gas refrigerator uses ammonia as the coolant, and it uses water, 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.

I am very interested in this and may have to try it myself, as i have an old rv refrigerator jut laying around. I dont think the heat tape will work(not nearly hot enough), but it would be very easy to use a lantern base burning lamp oil or low odor mineral spirits. Very cheap and effective.

 

Sorry if my comments were not complete. I would use a ceramic bead heater that contains a nichrome wire. This wire acts like a resistor and produces a very high temperature (hence the use of ceramic and nichrome). I use them at work and can easily produce spot temperatures of 4-500 degrees F.

You would be using 12 volts DC to power it of course. To accommodate the lower voltage you need to connect short sections of heater strip in parallel.

Of course after taking full credit for this idea, I must mention in passing that the propane refrigerator in my RV has just such a (115 VAC) heater coil as the backup function.

 

Thanks for the information! Did you install the heater coil or did it come like that?

Would you be able to harness heat from the exhaust system, like wraping tubing on the downpipe that comes off the exhaust manifold? I would think you could get temps over 1000 degrees here so you would either need a high flow fate of an oil that can handle high temps, this could then be used as the heat source for the refrigeration unit.

 

The method of heating the coil is independent of the endothermic action that creates the cooling.

As for using wood gasification, it can run anything that runs off of propane or natural gas even a gas turbine/engine. Once the gas is created, it will burn just as if you hooked a propane tank up to it.

The technology is actually very old. The otto engine/4 stroke engine was first patented in 1861 by by Alphonse Beau de Rochas. It was gasification units that powered these early engines before they began using gasoline.

You can do some searchs on Utube on the subject, there are piles of video there; Everything from generators to engines to stoves.

 

My waterheater has a heat exchange system from the hot radiator water of the motor. the water tank is ten gallons. The water of the heater becomes steaming hot. Do you think that a copper waterline coiled about the heat tube in the refer. would be hot enough to run the fridge while on the road?

 

It should work, i think they did that on the show "The Colony"

During world war II, civilians in France in some areas, converted their cars to run off of woods gas. you can do it too!

Check out this website, the "Vintage Technology museum". it has lots of tech, including some that "didn't pan out". but it's quite useful, in fact I may use it for a design for a BOV one day.

http://www.aqpl43.dsl.pipex.com/MUSEUM/museum.htm

Also, FYI, Woods gas is flammable due to the hydrogen and methane created , not CO (since it's already oxidised). good luck.

 

Also, FYI, Woods gas is flammable due to the hydrogen and methane created , not CO (since it's already oxidised). good luck.

I know that this is an old post, but I always want to dispel mistruths.

Contrary to what seems to be 'popular' belief, carbon monoxide (CO) WILL burn. It's typically produced by incomplete combustion (i.e. a fire that doesn't have sufficient heat and/or oxygen). It doesn't burn with the same intensity as some other gases since it is indeed partially oxidized already, but it will burn nonetheless. In fact, methane and carbon monoxide are the primary gases produced by wood gasifiers.

Here's a website that discusses this.
"Carbon monoxide does support combustion and burns with a pale blue flame. The blue flame used to be seen over the fires made from coke (essentially a very pure form of carbon) by night watchmen on industrial sites." http://www.chm.bris.ac.uk/motm/co/coh.htm

 

When I was a kid I knew a traapper that had an amonia fridge that had a pullout tank with a kerosene burner on it for a heat source. I believe that any propane fridge can be modified to run off a flame as long as it is the same btu output.
The problem with woodgas is its alot of work for a short burst of fuel. A propane fridge is a small flame burning along time, slow and steady.

 

this is a very important subject the ability to create subzero temps with any heat source would be invaluable i have been looking into this off and on for yrs. but find info hard to get. any fridg. tek's out there?

 

Wood gas is really easy to make, check mine out on you tube ,steven Fabiano

 

How ever you supply heat you still need some type of thermostat in the equation as otherwise the grudge will simply run non-stop until everything is frozen solid. Though in a hot climate and the inefficiency of a propane RV fridge it will mostly be running all the time anyways.

 

Propane refrigerators are not the most efficient things but the do work OK. It wouldn't be hard to convert one to work with a wood fire. I really like the idea of heat tape and solar to make it work. You could hook a little panel to a lead acid battery and be good to go.

 

Had one as a kid. Lots of them still around.


"Servel (also called Electrolux-Servel), starting in 1927, and continuing through 1956, built millions of gas and kerosene powered refrigerators, gas water heaters, gas air conditioners, and electric refrigerators. This site focuses mainly on the gas and kerosene powered refrigerators."




http://vintageservelrefrigerators.8k.com/

 

If you are going to buy new instead of find a scrap absorption fridge another way to go is with a 12VDC compressor fridge. This is NOT the 12V "coolers" that work off the Peltier Effect and only get to 40 degrees below ambient temps.

The inefficiency of the normal RV absorption fridge is what led me to order a compressor fridge in both my previous and current truck campers. This is not the same fridge as in a house as it is made to handle on road movements but works on the same principles. It uses a compressor that is powered by 12VDC instead of 110VAC. Even the 110V option is simply a power converter from 110V-to-12V.

Unlike in my previous RVs where I had to turn on the fridge a day ahead of time and pre-cool the food before I loaded it, when I turn on the fridge now it will start to make ice in about 45 minutes. Even out here in the desert it works GREAT while my friends with absorption fridges have to make sure to park with the fridge side in the shade and even add screens/fans to help.

My previous fridge ran non-stop for over a year on solar and batteries.

 

Another rv-ing thing is absorption fridges need to be still and very close to absolute level to operate. Compressor fridges do not.
Lotsa options for refrigeration.
We had an engine driven freeze plate fridge on the boat. One to two hours a day running kept it frozen. 6" of insulation helped...

 

Also the LEAST efficient mode for an RV absorption fridge is the 12V setting.