I have a pretty good understanding of how an electric refrigerator works -- a small motor-driven compressor, refrigerant gets hot when compressed, releases heat when it expands, etc.

But... how does a propane-fueled refrigerator work? It seems counter-intuitive to me to burn propane to make something cold.

tanstaafl.

I'd always wondered if there were a such thing as a propane-fueled refrigerator. Was even discussing the concept with my wife a couple of days ago.

In my theory of how such a device would operate, basically, the burning part and the cooling part are not related. The burning part is only responsible for turning the shaft of the compressor pump. The heat from the propane burn is exhausted in such a way as to be separate from the heat exchange mechanism of the fridge itself.

Dunno if they actually work that way, but seems logical from the way I was thinking about it.

http://www.nh3tech.org/absorption.html

Wow, completely different from my concept.

Have a look here and here.

Rod.

Edit: Not quick enough!

Far out! I especially liked this part:

The evaporator is supplied with hydrogen. The hydrogen passes across the surface of the ammonia. It lowers the ammonia vapor pressure enough to allow the liquid ammonia to evaporate. The evaporation of the ammonia extracts heat from the evaporator. This, in turn, extracts heat from the food storage space, lowering the temperature inside the refrigerator.


The operating principles are so elegant and simple (in execution, certainly not in concept!) that I wonder why all refrigerators aren't made that way.

If you used an electric heating element (instead of burning kerosene or propane) I wonder which type of refrigerator would be more economical to operate? Which would be more economical to build?

tanstaafl.

The really interesting application of this sort of technology is in something I've been meaning to build for years, solar-powered air conditioning. The ammonia absorption refrigeration cycle will run from any source of heat, so certainly solar power is possible, and it leads to a useful self-regulation regime where the hotter the day, the more cold you want, and the more energy you have available to produce it.

The electrolux cycle, which is the hydrogen buffered variant, has no moving parts at all and should run virtually indefinitely. Hydrogen leakage is the real limiting factor.

Of course, for hot but overcast areas of the world where there isn't enough sunlight, one could simply use nuclear waste as the heat source...

pca

I am really quite surprised no one has built this. I wonder if there's a reason. As in the amount of cooling power has less to do with the amount of heat gereated and more to do with how much material remains to be evaporated and then later cooled. Hmmm.... Trying to wrap my head around it now... And not succeeding very well.

Many very large refrigeration units do use the ammonia system, the US Army Cold Regions Research Lab (the place where many of the ice cores in the world go for analysis) for instance. I got a chance to tour it during college. They have an olypmic sized pool that they can freeze to perform scale boat hull strength testing for icebreakers.

-Zeke

At one time, back before Freon was invented, it was common for fridges to use ammonia (gas and compressor models) and sulfur dioxide (compressor models). Essentially, both are too dangerous to leave in the hands of consumers and both kinds were known to kill off entire families when containment fails.

Ammonia fridges are still common in motor homes and commercial installations.

Propane refrigerators are basically silent too. Very nice, but you don't really know if its running.

Very nice, but you don't really know if its running.

If the beer's cold, then it's running. Next question?

Which brings us to an odd tangent. How many of us have a small fridge in the living/computer room for nothing but beer and condiments?

Which brings us to an odd tangent. How many of us have a small fridge in the living/computer room for nothing but beer and condiments?

Ah, the memories... That topic takes me way way back to December 2003...

This thread reminds me of a joke I heard about beer in the UK.

It goes like... Q: Why do the British drink warm beer? A:
Because Lucas makes their refrigerators

Please take no offense, just a bad joke i heard.

More Lucas jokes http://www.mbz.org/info/fun/lucas/

EDIT: I thought this was great from this same page:

In reply to:

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Positive ground depends upon proper circuit functioning, which is the transmission of negative ions by retention of the visible spectral manifestation known as "smoke". Smoke is the thing that makes electrical circuits work; we know this to be true because every time one lets the smoke out of the electrical system, it stops working. This can be verified repeatedly through empirical testing.

When, for example, the smoke escapes from an electrical component (like, say, a Lucas voltage regulator), it will be observed that the component stops working. The function of the wire harness is to carry the smoke from one device to another; when the wire harness "springs a leak." And lets all the smoke out of the system, nothing works afterwards. Starter motors were frowned upon in British motorcycles for some time, largely because they consume large quantities of smoke, requiring very large wires.

---

Sean in NC

Ya know.... I even posted in that thread. I guess it shows I'm a little scattered of late. Things at work have been hell. Absolute hell. Oh well.