Friday, March 25, 2011

Pumps as Turbines have many advantages.

If you are good with welding you may want to consider making your own 'turbine' case to replace the pump case and use only the impeller, shaft, seals and bearings from a split case pump. This will allow you to design the turbine case with a much larger inlet to eliminate the restrictive pump outlet.  Note that pump outlet = turbine inlet. This will get you a little more efficiency in converting the energy in the water ( head X flow ) to mechanical shaft energy.

You could even buy just the parts you need. Example shown here. This is a project I'm considering, at least on paper. Another approach might be to modify a split case pump housing with a second outlet. (inlet with respect to turbine operation) Since these housings are mostly made of cast steel it would involve welding of cast steel or cast iron. I'm not sure it would be worth it for maybe a 5% boost in efficiency. But if you like to tweak and optimize ...


Anonymous said...

Great post thanks

Colin said...


I have read your hydropower blog with great interest and found it very informative.

I am wandering if you would help me with my following query on using a PAT setup.

My situation is as follows:

We have access to a reliable water source (stream) close to our house along with an old disused water pumping station. The water spring is conveniently piped to the disused building, where a Turbine could be quite easily setup. However the head from the source of the spring to the building is only approximate 2m. I have not as yet measured the water flow. What particularly interests me about this project is the sloping nature of the site away from the building. Piping the water away from the building could probably achieve a "suctionhead" of a further say 40m.

The question is this: can a PAT configuration work in this situation I.e.  can the "suction" of the "after flow" be used to harness the power of say a total gravitation fall of 42m?

The existence of the existing civil engineering lends itself to this sort of setup if it could be made to work (no new water intake required, no building to construct, electricity already wired from the house to the old pump house etc)

Your thoughts on this would be gratefully received. I hope you will excuse my ignorance of the correct terminology as I am new comer to the world of hydropower.

Kind regards
United Kingdom

Rob said...

Yes a PaT can theoretically utilize up to about 10 meters (32') of suction head. The practical limit is somewhat less because you will draw a vacuum which will spoil the suction and cause cavitation and turbulence. Keep in mind that you'll have to match the impeller diameter to the total of pressure head + suction head. See blog for formula. You probably should place the PaT 8M up from the lowest discharge point to maximize your power.
Happy Hydro

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Anonymous said...

Rob, is this article on increasing pressure by increasing the speed of the water via inducing a vortex, instead of increasing head, scientifically viable?

Rob said...

The Hasselberger patent description uses many subjective and pseudo-scientific terms like 'living energy','cross vortices' which activate my BS detectors.
Bottom line ... if this was a better 'mousetrap' it would have caught on by now.

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Angie @ The Country Chic Cottage said...

Always amazed at the power of water. Really enjoy your blog. My question is I have a large creek close to my house. It has very little fall. There is one natural dam that is solid rock. It has a pond of water about 60 feet long and 20 feet wide with an average depth of 3 to 4 feet. Do you think a PAT would work if I run 100 feet of pipe with 1 to 2 feet drop. Your thoughts greatly appreciated.

Rob said...

Hi Angie,
The electrical power you could get from 3 feet of 'head' and an assumed flow of say 60 gallons per minute would amount to around 15 watts. And if you had to run 100 feet of 4 inch pipe it would take a very long time to even pay for that pipe and the labor to put it in. So you would be much better off with some solar panels, or if you can wait a few years, a LENR powered generator.
See my last few posts to learn more about Low Energy Nuclear Reactions.

LENR is Renewable Energy

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Anonymous said...

Hi Rob!

A grat blog and a really great and cheap idea of harnessing renewable energy. Thumbs up for your idea!

May I ask you a question. Does this technology has limitations concerning the height of fall? I am considering installing such a system for a flow range between 0.4 and 1 m³/s and a height of about 4 metres. Do you think a pump as turbine will work in this specific situation?

Thanks in advance,

Rob said...

Hi Thomas,
The higher the head pressure, the better.
I can give more detailed responses if you contact me directly with a return email address, not 'anonymously'.
Happy Hydro,