Mollison's Trompe - alternative energy

Brian:

You are on to something there...but that still needs measurable head pressure that is sure to get noticed on a flat ditch. Could it be submerged in a total depth of 1/2 meter with siphon outflow at the base? I think i could do a divot in the stream bottom that would not get noticed...hmmm

You need half a meter of head or more for any reasonable trompe system. I ran something on 8 inches of head at one stage but that is just a waste of time. I have no idea where Bruce Leavitt got the idea that it needs 4 ft of head to run a trompe. And in his video, he has way over complicated air en training into a 4 inch down pipe. A half inch pipe down the middle of the 4 inch pipe that goes about 6 inches down at the entry is all that you want or need. Here is the largest pulser pump that I made. (pictures) pulser pump pictures

Ty Morrison wrote:Brian:

You are on to something there...but that still needs measurable head pressure that is sure to get noticed on a flat ditch. Could it be submerged in a total depth of 1/2 meter with siphon outflow at the base? I think i could do a divot in the stream bottom that would not get noticed...hmmm

Brian's Vortex example is quite persuasive.  Having sworn-off some of my other fast-flow solutions, I am going to come at this a different way.  Things I know: My water moves at 1 ft per second and has a cross-section of about 288 square inches.  It is in a channel that is fairly uniform and 6 inches deep by 48 inches wide.  My goal is to lift the water 6 feet vertically to fill a reservoir at the top of my property.  I will then use gravity flow to irrigate on my property.  I do not intend to fill a reservoir as fast as I can deplete it.  Say one day to deplete, three days to fill.

This website may help me figure out some things necessary to create a vortex.  Next, I want to see how it can 'lift' water on its own as Brain notes in his video.

http://www.builditsolar.com/Projects/Hydro/FlowOfRiver/FlowOfRiver.htm

So I have 2 square feet of water moving at 1.466 MPH which is about using the chart and information on the website for an example turbine, I think I could get 1.4 W/H from a turbine.  Like the author of the web-site I have found all the same links.  The spiral pump was what got me going, I simply could not get it to move an undershot water wheel.

This is a good place to explore...Maybe a Gorlov Turbine?  I still only want to lift the water, not make electricity, too many problems with storage.

And then I found this...still: 0.7 of a meter is that magic 18 inches of fall.

http://www.treehugger.com/renewable-energy/gravitational-vortex-power-plant-is-safe-for-fish.html

The idea of the Trompe has been around since the days of the roman empire. I would imagine it was an accidental discovery when bringing water into cities via aqueducts then dropping it through a pip into a cistern. Well eventually that cistern pressurized and started blowing out fountain heads or some such. I would imagine the Romans may have even used them for cooling in some way.

I think the idea is to use water that drops from a high place, like say a waterfall. The higher the water drops from the higher your pressure can be. If my scuba training holds in this situation you get something like 14psi for every 33 feet of water depth/drop. I would imagine falling water might be more than this.

Now if you combine the Trompe with a ram pump I would imagine you can do lots more stuff too.

I wonder what kind of pressure you might get from a drain pipe on a skyscraper?

Rob Sigg wrote:I recently built a small scale trompe, here are the specs:

Closed system using a bucket of water being pumped to the top of the inlet and then returning to the bucket. Im doing this only to test out the dynamics of it, this will be used on a natural water way.

3/4 inch inlet with one straw for air introduction, this is about 8 feet tall
transition to 1 1/2 transfer pipe then to a vertical 3" air entrapment with 1/4 air compression gauge and valve. The air chamber is about 2 feet tall.
The outlet part of the transfer pipe then goes to 1 ". The outlet pipe is about 5 feet tall. I experimented with a one way valve to try and create back pressure. Youtube Mr. Teslonians  Trompe Hammer for the gist of this.


No matter what I do I cannot seem to generate more than 1 PSI and of course once the pressure is releases the water level comes up and spills out of the top. I want to test this on actual falling water because I think it has to do with the volume of water going into the inlet pipe, it doesn't seem to be enough since im pumping through a 1/2 tube into a 3/4 inlet pipe.


If anyone has any further ideas/thoughts I would appreciate it and I can post more details if desired. I tried to contact Mr. Telonian but I can't find his contact info anywhere, he would certainly know the answer.

Sea level air pressure is 14.7 (1 atmosphere) psi. For every 33 feet of water depth that pressure will increase by 14.7 psi. At 99 feet under the surface of the sea you will increase your air pressure by to 4 atmospheres , which will be 58.8 psi. These calculations are what you would get at sea level, I am sure the calculations will change a bit at diff elevations. I think for a trompe to work the pressure going into the holding tank must be greater than that leaving the tank or you do not get the flow in that you need to separate the air from the water in the holding tank. Also there must be some pressure on the outlet to maintain or build pressure in the tank.

I think your test system is to small to build any significant pressure. You might want to experiment with a ram pump if you are looking to move water around.

If you watch Bill's vid again you will note  they had something like a 300 ft drive pipe with over 100 ft of drop going into a 55 gallon drum which eventually exploded to to high pressure.

@Brian White.
I wanted to take the time to say thank you for all the information you freely share on your research. In the past month I have come across your comments and videos for 3 unrelated topics and you helped me understand each one better. Cheers

Mario Lazetti wrote:@Brian White.
I wanted to take the time to say thank you for all the information you freely share on your research. In the past month I have come across your comments and videos for 3 unrelated topics and you helped me understand each one better. Cheers

Thanks,  you are welcome.   I'd love to go back into this stuff,  but you really have to fight so hard to get people to try it. 2 groups researched the pulser pump (Trompe powering an airlift pump)  in colleges (in Canada and in England).  Both made models smaller than what I made and both screwed up.  If you don't size your airlift pipes so that you have "plug flow" you will get crap efficiency.   If you don't use a constriction,  (I just used the hole in a bead to even out the flow of air from the trompe to the airlift pump), you will also get crap efficiency.   The second group used 1 trompe to power 2 airlift pumps.  I advised them and helped them size the trompe and the airlift pumps and told them to use 2 adjustable air valves  (the ones for getting the air flow right for the airstones in fish aquariums) between the trompe and the 2 airlift pumps.  They dispensed with the air valves because they didn't understand why they were needed!!! and they got and reported efficiencies of about 1%.  So,  I got "peer review" but it was sabotaged by stupidity.    When you don't use valves,  all the air goes to one airlift pump and you get annular flow in that one and hardly any pumping! And no air going to the second airlift pump at all.   Its kind of like having a short circuit in an electrical system.    I'm sure trompes have a place in the world but the only way to have people understand them is to have  a working trompe made of see through material in  an alternative energy demonstration.  It doesn't need to be very big.   a meter deep,  300 liters per minute of water through it,  and a head of half a meter will work just fine and can run a few rows of NFT greenhouse tomatoes or something like that.  All with no moving parts.  I have used mini airlift pumps for about 5 years in my garden to recirculate water in planters.   It works well but nobody else tries it.   I have even made compost tea "breweries  where the airlift circulates water through the compost to rot it way quicker and make huge amounts of compost tea.   Very little interest.  I don't know why.  

@Brian White.

I am working on forming an organization here in Colorado around technologies and techniques that would be useful in permaculture designs. Your expertise would be invaluable for our first event: modifying an existing dam to pump water, compress air, or make small amounts of electricity as the seasons demand. If you would be interested in being a guest expert in person or over teleconference, please reply to the email address below.

Thank you!
David Haight
Dave@higherform.com

A trompe only needs a difference in input and output height. An example is to have 6” diameter pipe the output needs to be at least 12” lower to have the flow and the pressure is usually calculated on the return height. And to build pressure just dig a deep hole.