I was recently listening to an audio recording of a 1983 permaculture design course taught by bill mollison, and he was going over the topic of putting water to work for you. I was introduced to two new concepts during the most recent lesson I was listening to. Both were systems that could be used to create power through the natural falling of water through a system (such as water coming from a dam pipe). I have been trying to find more resources regarding them but have had very little luck so far, especially any information about the trompe air compression system. Does anyone out there know where I can find a good resource of information for these, like a book? Has anyone out there had any experience with these they could share?

Nathan Funke : Thank you for Bringing this up ! A few others have tried and Their thoughts got buried in Useless Trivia - Just goes to show you -
(Something?)

The Trompe system for producing Compressed air is truly an ancient system, the last known working models of which were in Ontario Canada and had
an energy transportation efficiency of over 80% - better than Electrical Generation, OR Electrical Transportation !

A regular Google search should have directed you to Wikipedia, and to a short article that shares the information that This Technology has had a long
history in smelting ores, and in mining where compressed air is highly desired for many reasons, Rock Drills being just one !

Today this seemingly esoteric information is therefor to be found tucked into a cranny in a dark corner of a Mining Engineers, brain - more so in those
brains over 70 years old, than in recent Mining School Grads ! ( I come from an Old mining town )

In the upper right of this page above the 'Permies.com Video of the day' is the 'Permies Toolbox', If you select the Search Engine feature, and then select
to do a google search within All of the Combined Permies.com Forum Threads prior to posting a question to these forum pages, you will find a listing of
the people that have posted Threads on this subject, and the Threads that you can then go to for more information!

This will give you Two more ways to contact people who want to talk about what you want to talk about, via P.M., or your new post on their threads !

Finally, and though last not the least, at the bottom of the page this is posted to is the '' SIMILAR THREADS '' section which is a computer generated list
of mostly related topics, which can only be generated by your post !

All of these tools are under utilized here at Permies, your posting just helped to spread the word ! For the Good of the Craft ! hope this helps us all !

For some further research that should be Water Rams, or Hydraulic Rams, Translating from the Australian is not all that easy ! BIG AL !

Think like Fire!, Flow like a Gas!, Don't be the Marshmallow ! As always, your comments and Questions are solicited and Welcome. PYRO - Logically A.L.

I've been reading up on this over the past week or so. Such simple technology, yet so useful.

Some ideas have come out of my reading:

Make a compressed air distribution network - use the air directly to power tools etc, rather than converting to electricity

Refrigeration - expanding air cool. Air supplied by a trompe is compressed and simultaneously cooled to the same temperature as the water, say around 15 degrees centigrade. If you let that air expand so that it cools a refrigerator as it does so you could have free cooling, year round with no maintenance!! By my rather rough and ready estimation a trompe with a fall of around 2m should be sufficient to cool below zero centigrade as the air re-expands.

Air conditioning - likewise with refrigeration, pumping cool, clean air at pressure into a home that cools further as it expands seems like a winner.

It is hard to get figures on how efficient a pulsar pump/trompe combo can be - a lot of "proper" research needs to be done to nail down the parameters - but some demo models show water being pumped 10ft or so higher than the water supply, from relatively low falls. Animal watering in the field. Selective watering of crops. Continuous trickle refill of larger water storage tanks. Pumping drinking water to a roof top tank to supply water with reasonable pressure head.

As far as I can see there are two separate elements of the system that need more analysis. First is the inlet pipe and venturi configuration. I have a suspicion that a turbulent flow in the pipe will carry more air per unit of water, but that ultimately the sizing of the pipes will be based on the water flow available. Perhaps multiple narrower diameter pipes will work more effectively than a single wide pipe? It seems like these questions are essentially unexplored.

The other aspect is how best to design and size the pulsar pump configuration. This should, in theory, be easier to get a handle on - for a given design you basically have a known air pressure and the height you can lift the water too will be dependent on that. You will have a trade off between volume of water and height you can lift it to. Perhaps 10 liters per minute to 1m above your water source, vrs 1 liter per minute to 10m above the water source.

All fun variable, but quite challenging to define and explore without some fairly chunky test rigs.

Michael Cox : I like all of your ideas for using compressed air, though you would have to be very lucky in your topography to be able to run more than one power tool at a time
usually not a problem for people with just two hands !

There were several more comments made as separate Threads that got posted to Meaningless Drivel, Actually I expect all of this information should be easily found inText-
books of Mining Engineers, though it maybe more fully covered in 80 year old texts !

The second part of the recording, also available as a Video on You Tube, Concerned the use of a second 'old times'/off grid technology Water (hydraulic) Ramps,
Todays best Water Rams are coming out of Canada and Australia, with very little head they can raise up to 1/10th of the entire 'flow' to great heights and supply all your water
needs by doing it 24/7/ 365 needing only minimum protection from cold - running water does not freeze ! That was being recommended for the purpose of raising water to a
distant field or home ! Hope this helps, if you find any good sources out there please make sure it gets posted here ! For the Craft! All comments welcome here ! BIG AL

Al - the early mining books may have practical info on Trompes, however the physics and mathematics behind the two phase flow in the various vertical pipes was not understood then, and is still very hard to model now. Simple systems can be modelled but when they get messy it all becomes very hard. We spent quite a bit of time looking at them on my Chem Eng degree.

I suspect that they just built them as large as they practically could and made use of whatever compressed air flow they got. The actual pressure head of the air is easy to calculate - just not how much of it you will get, or how to optimise the dimensions of your tower to maximise entrained air flow. I guess with a large column already constructed they could tweak the venturiis a certain amount, but you wouldn't be able to change the pipe diameter.

I've been researching this type of system as well and I wanted to share some thoughts of what I might try with them. First of all, I don't have access to normal flowing water, so I am considering how such a system could be used for occasional flow to build up compressed air during those times for use in other times. The first topic I looked at was what is a cheap airtight container. I found 5 gallon buckets are a common airtight-sealable container if they have the lid on right. A rain barrel might be able to be used as well, not sure. Second, a standard rain gutter off a house seems like a good place to start in building a trompe. Altering the downspout to increase air draw is one thing I was considering (silly but I think straws glued along edges of downspout would function), but I think it would suck down a decent amount of air without modification. Third, roof runoff is something I would like to use to water my gardens, so the pipe could be directed after the trompe to drier beds or a rain barrel for later use.

If these elements are put together, I think a system could be built that during every rain stores up pressurized air in a 5 gallon container, as well as fills a rain barrel or redirects water somewhere (or the redirection could be after overflow of rain barrel). The slightly pressurized air would be piped to the back porch or somewhere else people gather to cool that area in the summer.

A few other thoughts I've had are that putting a 2x4 or other material should block flow along the bottom of the airtight container to encourage the flow upward by the compressed air pocket. Also, I wonder if this size may not generate enough pressure with the fall of a single story house, but I would think it might generate enough to be somewhat useful, not to mention free operation.

Further thinking on this, perhaps given the size of a 5 gallon bucket experiment, this amount of air and pressure would probably be a good fit for keeping a cooler or small box cool.

Just a few thoughts on this thread.

It seems to me that if you can produce "pressures" high enough from a water ram pump to push water up higher then that energy may be better used differently. Especially when you must waste 90% of the water to do so, that must reduce the efficiency drastically.

Compressors have two important factors Maximum PSI and Cubic feet per minute production. Seems to me that more water will capture more air (by volume) in a trompe. Even though having a higher trompe could produce higher velocities of flow which should also capture more air (by percentage) I do not think it will be as efficient as having more water flowing.

Micheal: Dont forget that you could put a air powered generator in one of those refrigeration units to first produce power then refrigeration off from the exhaust.

Noah: I am curious as to how much PSI a 5 gallon bucket can safely hold and how much cooling would that provide?

Also I have been thinking of a way to integrate these technologies that uses the pulsar water pump process to further compress the air into a separate chamber rather than pump water up to a higher elevation. After considering the physics, I think this may be the more efficient use of the pump "pressures", that I first referred to in this post. Question, thoughts and comments please!

Terry Frankeberger : Certainly a combination of the Trompe To produce air, no moving parts, and the Air lift pump, ditto, beats The Water Ram with its poor efficiencies,
and moving parts! But lets not over think this, though maybe my Soil Conditions will let me dig a deep hole in the ground close to my stream so that I could create
a Trompe, building a safe hole in the ground, will take as much time and materials as building, installing, and tweaking a water ram, and you can listen to a water ram and
diagnose its simple problems and plan on when it will be convenient for you to work on it with simple tools ! While running water rarely freezes, the Ram Pump will need
an insulated house in winter!

If our piddling little spring and our out of tune water ram can only produce a 1/2 gal a minute, that is still 720 gal a day 24 /7/365.

And if you are blessed with a waterfall you can pipe your water directly where it is needed, or pipe it to your water ram and with the 'head' you gain (if not efficiency )
you will gain in gallons delivered up hill !

The biggest benefit to having access to the Trompe with probably be for people raising fish in small ponds, and needing aeration and water circulation, and possibly a
fantastically lucky siting of your work shop to take advantage of air tools, here most of the gains in this tech, have mostly been made in assuming high air pressures and
not in economies of operation ! Just my two cents Y.M.M.V. Big AL

Big Al: I must not have been very clear.

My Idea is to:
step1: Estrain air into water.
Step2: Capture air just above a tee.
Step3: stop the flow of the trompe with flapper valve at the other side of the tee.
Step4: flow stopping pressure compresses the air trough a check valve into an airtight chamber.
Step5: Flapper valve reopens process restarts.

good results: More air captured and higher pressures achieved in a shorter system (basically a ram-pump sized system)
bad results: no longer have iso-thermic compression

I hope this clarifies my points in my previous post

Terry Frankelberger : You are obviously thinking outside the box, Congratulations, However I am not getting a clear picture of what you are proposing, I expect that I have
allowed my already formed ideas of how the system 'seems ' to work to block my understanding of what you want to do. Could you make a sketch, it might help drive it home

For the good of the Crafts ! BIG AL !

After considering the efficiency of my previous idea I have determined an even better method to compress air by integrating the ram pump with a single piston to compress the air. This new idea will allow for more acceleration within the water than two phase flow where the air will resist the acceleration.

The basic idea is to have a ram pump to push a piston that would compress air past a check valve into and air tight container. As the piston returns to start position it would draw new air into the compression chamber.

good results: Even more cubic feet per minute air flow and high pressure compression probably enough of both to operate shop tools and atc. Also smaller drop required than a trompe.

bad results: Not an iso-thermic compression. (could use drain water to cool this air before use though if cold air is desired)


Big Al: picture is a bad schematic of my previous idea I would have had it in the last post but I did not know how to attach. I have not made any schematic for the piston idea yet.

Hi Terry,

I've just come across this post and noticed it's a couple of years ago now. Have you had any further experience with this type of system?

Has anyone had success putting something like this into practice and if so what were the applications?

Thanks.

Hi Sandy

I do not know of anyone using a system like the one that I sketched.

My goal here was to make a low cost water powered air compressor. I have since thought of another more efficient way. I am not able to make either of these ideas because (sadly) I do not have a stream on my property.