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Hydraulic motor to turn generator
By rosscat, Section Hydro Posted on Thu Mar 24, 2005 at 03:58:15 PM MST
Help

I live next to a fairly large river with about 5 ft sec flow with a large vollume of water What I am thinking of doing is submerging a three ft fan blade with a hydraulic pump fastened to it and then to a hyd motor to turn a small generator I live totaly off grid and use a Trace 48/40 with very large forklift batterys I charge the batterys with a small 10 kw diesel generator We also use a wind generator that I fabracated myself wich when running substantially reduces the amount of time I have to run the generator .SO if I could turn a small generator with the hydro pump even if it only generated 4 amps/24 hrs would help a lot.Dose anyone know if this will work? if not What will ? Any ideas?

Hydraulic motor to turn generator | 19 comments (19 topical)

Re: Hydraulic motor to turn generator (3.00 / 0) (#1)
by farmerfrank on Thu Mar 24, 2005 at 10:19:50 AM MST

Sure a hydraulic system can be made to work and the better it si designed the more efficient it will work. The best hydraulic set up may be 85% efficient. Just taking any old pump and hooking it up to a surplus motor through small,long lines to drive a scrap altenator and you might to well to get 20 % of your oringinal energy back. The nice thing about hydraulics are that you can cchieve infinite speed control and boost torue but at the cost of efficiency. Just my 2 pennys worth

Re: Hydraulic motor to turn generator (3.00 / 0) (#2)
by bob golding on Thu Mar 24, 2005 at 01:15:28 PM MST

hi, make sure you dont let any of the oil get into the stream. doesnt need a lot to pollute the watercourse.

bob golding

Water pump instead? (3.00 / 0) (#3)
by Norm on Thu Mar 24, 2005 at 03:33:23 PM MST

Why not just hook the blade up to a
centrifugal water pump? Pump the water to a water
wheel or turbine? Even in the wintertime as long
as you have a continuous flow....
Actually it's still hydraulic but the fluid
would be free!
( :>) Norm
( :>) Norm

Re: Hydraulic motor to turn generator (3.00 / 0) (#4)
by healerenergy on Thu Mar 24, 2005 at 03:36:01 PM MST

Build a closed loop system with out a reservoir and use some kind of biodegradable oil or vegetable oil mabe cotton seed oil also a fan blade may not stand up to the water because it has 800 times the force of air because of it's density.
Energy comes from many Sources the trick is knowing how to tap into it.

Re: Hydraulic motor to turn generator (3.00 / 0) (#5)
by rotornuts on Thu Mar 24, 2005 at 04:57:29 PM MST

maybe if you got some big old outboard or inboard props and lined them up on a common shaft far enough apart to let the water regain nonturbulent flow between them? just don't tell doug what your doing.

Re: Hydraulic motor to turn generator (3.00 / 0) (#6)
by electrondady1 on Thu Mar 24, 2005 at 07:00:54 PM MST

how about a big paddle wheel like they had on those old river boats , tough on the jet ski's i guess

Re: Hydraulic motor to turn generator (3.00 / 0) (#7)
by LEXX on Thu Mar 24, 2005 at 09:51:45 PM MST

That's just what I've been thinking for quite some time, it would be a very easy way to get energy from a river with very little rise in water depth. You could mount it on a raft with all the neccesary PM genny or whatever on it and tie it off so that it would just bob along out there making you electricity. The only hard part would be making sure that the leads were electrically and physically secure. I guess if you wanted to be artistic with it you could make it actually look like a paddlewheeler with the genny inside the hull! lol One thing tho, if yu weren't absolutely sure of the year round depth of the river you would be wise to put on a few guards so that the blades of the paddles wouldn't scrape bottom.
LEXX

[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#8)
by Nando on Fri Mar 25, 2005 at 03:19:53 PM MST

Your idea, though logical, it is in-efficient.
Better describe your site in a more well defined manner with the Water velocity and the water volume as well.

In run of the River turbines producing from 400 to about 2 KW coupled generators have been installed in several countries, of course there are other designs that have greater capability.

A dual contra-rotating propellers can drive a generator, also with much reduced efficiency this set up can drive a pump to bring water out of the river at a known constant pressure (like 30 to 60 PSI)with a known volume ( liter/sec) to run a Turgo turbine generating a defined power.--under the same conditions, as above, the power generated is around 1/2.

Regards

Nando

Re: Hydraulic motor to turn generator (3.00 / 0) (#9)
by JB on Fri Mar 25, 2005 at 07:28:59 PM MST

If you do a search on otherpower Dan had some pictures of one he and his neighbors built for his creek. It had a lot of good info. JB

[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#10)
by scottsAI on Fri Mar 25, 2005 at 08:29:36 PM MST

foot propeller in 5 feet/s water flow can generate about 4.8kwhr per day.
8kwhr per day looks to be more than you need. No more diesel generator!

The energy in a Dam is based on height (P.E.), where here we are getting the energy from the water based on velocity or K.E.

The energy in the water is calculated by:
K.E. = ½ m v^2 K.E. the joules per sec = watts
v = water velocity in m/s= 5ft/s * 12in/ft * 0.0254m/in = 1.524m/s
m = (kg) mass of water in 1 sec = vol * density of water
= pi*(18in*.0254m/in)^2 * 1.524m * 1000kg/m^3 = 1002kg

watts = ½ * 1002 * 1.524^2 = 1163.6 watts or 28kwhr per day.

Interesting link about propellers:
http://mystic.math.neu.edu/gorban/Gorlov2001.pdf

With that in mind. The best propeller is 35% eff, typical propeller is 20% according to the above article.
28Kwhr * .2 = 5.6kwhr per day.
But that's not the end. The generator is 95% eff at best to 85% for a good one.
5.6* .85 = 4.8kwhr per day.

Any additional power transformations you add will reduce power out.
Best to have the generator attached to the propeller directly. The Gorlov turbine can be used vertically. Eliminating any gears, belts which reduce total power. The torque is high on the shaft, will need a very beefy bearing. Maybe use a front wheel bearing from a vehicle. Two bearings on a shaft are needed, second one is a pillow bearing?

Putting a shroud around the propeller can increase the generated power. I don't have any numbers on how effective it can be. A smaller dia propeller could then be used. Use the equations to figure a propeller dia that meets your energy needs. Always can use extra larger or two smaller generators and use power to heat water...

Sure you don't want to build a larger wind machine? Might be easier.
Have fun.

Re: Hydraulic motor to turn generator (3.00 / 0) (#11)
by rotornuts on Sat Mar 26, 2005 at 02:32:03 AM MST

I'd like to see the setup that will hold a 3 foot prop in a river flowing at 5 feet per second. Imagine the forces. Thanks for the link it's a good read. Maybe the Gorlov helical turbine would be a good choice in a version smaller than the one mounted in the test stand.

[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#16)
by rosscat on Sun Mar 27, 2005 at 08:14:12 AM MST

Thank You for youre comments they were very helpfull .I think the Gorlovs turbine concept is the most practical type of propulsion .Below my house on the river the bank goes vertical about 10'deep by 25'accross wich would allow me to install A vertical turbine fairly easy.I am thinking a Turbine about 3'dia by 5'in lengh .Can you help me with the math? How much Torqe will this produce? I am still thinking of some sort of a gear pump to ether directly power a generator trough a hyd motor or to a pelton wheel depending on psi.The main reason is this river is fished heavy with drift boats 6 month a year.With this in mind the whole system could be submerged and only hoses ran to shore under water.The water level varies from 10'low in summer to 18'high during the rainy season.Any help with design comments or any other issues would very much appreciated .Thank You

[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#12)
by Peppyy on Sat Mar 26, 2005 at 07:02:32 AM MST

Has anyone tried something resembling a VAWT in a flowing river? I would think that depending on the design there could be a lot of available power at low rpm which could then be geared up to run a small genny.

I have a nice almost flat river out back which floods my yard every year. In 400' of frontage I don't think I have more than a couple feet of drop but the flow rate is constant. There is even a new beaver dam in one spot near one of the campsites, "Somewhere Else", that is the site name.

This sounds like a worthwile summer project. I have always wished that I had a brook with a large drop like Brimstone Brook on the farthest edge of my property 1000+ feet away, but I now see potential energy much closer to home.
Pep

Re: Hydraulic motor to turn generator (3.00 / 0) (#13)
by TomW on Sat Mar 26, 2005 at 07:12:23 AM MST

peppy;

Wouldn't that be like a paddle wheel type prime mover? Only on a horizontal axis with half of it out of the water. I always thought this would be workable.

Cheers.

TomW

The Truth is the Truth, even if no one believes it; and a lie is a lie even if everyone believes it

[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#14)
by Peppyy on Sat Mar 26, 2005 at 10:58:18 AM MST

That would be the old undershot wheel idea you are talki8ng about, right?
Pep
[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#15)
by TomW on Sat Mar 26, 2005 at 01:24:08 PM MST

peppyy;

Well, actually a variant. More like a device that looks like a side wheel paddle wheel boat. floats on surface and paddle wheel turns in the current.

you could probably rig such a device and call it a dock, swimming float or a jetty to avoid it being labeled a hazard to navigation. You could tether it either to the bottom or the bank and it could float as needed and be retrieved if you know flooding will occur. Probably very inefficient but would work at some level. I have thought on this a lot over the years. I have no hydro resource so mostly just a brain exercise.

Cheers.

TomW

The Truth is the Truth, even if no one believes it; and a lie is a lie even if everyone believes it

[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#17)
by Peppyy on Sun Mar 27, 2005 at 11:19:07 AM MST

This morning, when there was still a crust on the snow, I walked over to the river for a look. The current water level is about average and the beavers have built a small dam on the other side of the river which just happens to create a channel on my side. It is about 3 feet wide and 6 inches deep and flows rather guickly for about 10 feet. It looks like they may have done most of the work for me.

If I make a simple removable stand for each end of an axle, one for the island and one for shore with a genny mount on it I could use something like a wire spool to build a wheel and Tada! instant power?
Pep
[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#18)
by ghurd on Sun Mar 27, 2005 at 11:44:14 PM MST

Beavers will cover things that make noise.
Like running splashing flowing churning water.

It will not be long before they fill in the 'overflow' water way.

I have thought about tearing a slot in a dam 2 feet deep in the center of a dam,
fixing a PVC pipe, 5 feet out both sides, then feeding the pipe to a genny.
They will fix the slot in a day or 2.
Should keep the water sound low.

If beavers were recently 're-introduced' into your area, remember there was a
reason the old timers spent so much effort in eradicating them.
Good luck.
G-
Ghurd.info
[ Parent ]

Re: Hydraulic motor to turn generator (3.00 / 0) (#19)
by Peppyy on Mon Mar 28, 2005 at 05:58:01 AM MST

I think they built this one out of boredom or perhaps to give some young-uns a lesson. They have a whole swamp damed up above. The state comes in every year and "relocates" them somewhere else. Don't think they ever get them all. We have a flood watch here till tomorrow so I will keep an eye on what happens to the flow.
Pep
[ Parent ]

Hydraulic motor to turn generator | 19 comments (19 topical)

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