12V small hydroelectric turbine on a river

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the middle
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by the middle » 15/09/08, 15:36

renaud67 wrote:Hello,
I already stuck this place there somewhere but failing to find it
http://www.moreau-fr.net/proto/turbine/index.html
voilà
good achievement ...

: Arrow: Hello,
This turbine is not suitable in this case.
It takes pressure, so height ... :?
Otherwise, it's a beautiful beast :D
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by Christophe » 16/09/08, 12:39

+1 with the Righteous ... although ... with 2 m of water it could go, I think.

Boblamouche wrote:Your estimate seems very realistic to me. But could we not increase the radius of the wheel, for example 30cm, in order to increase the torque and therefore the power?


Am not a specialist but I would say no: it is the speed of the stream and the radius which will give your speed of rotation of the wheel. If you increase the radius too much, the speed of rotation of the wheel will be too low and the counter torque too great to start and don't forget that the alternator must rotate at a minimum speed to deliver = couplings!
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by Boblamouche » 26/10/08, 22:53

Hello!
I come back talking about my little turbine:

I ran the alternator this afternoon. it provides a lot of current (I did a test on a 75w load) on the other hand it is very old and mostly worn. It comes from a 2cv.
So I did some calculations with an alternator efficiency of 0,4 after what I read here and there and after a review (change the bearings ...)
(when I am told in class that a synchronous is in the 0,95 ... well, it's not the same powers too.).

I work on a useful power of 50W, to recharge my battery when I am not using it.

With a home-made pinion-chain reducer which I estimate at 0,6 (friction bearings included) I arrive with a theoretical output of my installation at ... 0,24. Nothing to get up in the morning.

I took again the calculations of Christophe (see in this subject) and with a wheel of the same diameter and a speed of 5km / h, I must hold a submerged surface of 300cm² ... for 208W approximately of energy.

The solution I am considering: 3 paddle wheels of 20cm with 10 * 10 submerged surface. All on the same axis: a large steel bar very heavy to have an inertia effect. supported by rolling bearings on each side.
The system must therefore be started manually but its not a problem.

What do you think?

Good night
Bob

PS: If you are interested, I will try to show you the progress of my work. But since I want it to work for the summer, I'm not in a rush. 8)
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by Christophe » 26/10/08, 23:15

Ah good to see you again!

300 cm² is not that huge for a single paddle wheel!

It is only 30 cm * 10 cm of submerged blade ...

For me it will be easier to make a big one than 3 small ...

I started "mine" but very slowly like you:
https://www.econologie.com/forums/tambour-de ... t6303.html
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by Boblamouche » 27/10/08, 10:43

Very interesting your project!
For the paddle wheel (s), I see that you are using a washing machine drum. For my part I thought of cutting two wooden plates in a circle, making grooves in the router in which I would use as a support for my blades. everything fits thanks to threaded rods.

The problem is that I don't know if the straight blades are effective or if I shouldn't think about working on curved blades.
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by Boblamouche » 24/12/08, 22:35

Hello and happy holidays!

While the family is busy preparing for the holidays, I embarked on the construction of a prototype.
I saw that Christophe had advanced his project: https://www.econologie.com/forums/tambour-de ... t6303.html

For my part, I stayed on the same idea: a classic paddle wheel of 8 straight blades. on the other hand, I carried the surface of the blades from 300 to 500 cm² hoping to recover more power.
I built it all day in wood (so quite heavy) I miss more than past the axis and mounted on bearings to try to balance it a little.

here is the monster:

Image

Image

Image

Its diameter is 60cm and the blades are 50 * 10cm.
The axis must be 3cm in diameter (a tube therefore) with at the end a gear / chain reduction that I have not yet calculated, I am waiting to do speed tests with the wheel.
This homemade reducer will give on a 2hp alternator which will charge me (I hope) about 60 / 70w of useful power in 12V DC.

I remind you that the goal is to supply a load of around 100W with 12v DC (lighting and car station) and I have a battery to buffer energy. The turbine is therefore used to recharge it.

Greetings
Bob
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by Olivier22 » 25/12/08, 00:00

Hello ! Congratulations on your project! Given the progress my advice comes a little late, here I am: a little clarification: the diameter of the wheel does not play in the power! Let's say that for a given flow rate and a given blade area, a large wheel will give more torque and a small wheel will give more speed! So the "good" diameter, it depends on your alternator and the charging intensity ... At a given intensity, for a given speed (preferably a speed where the output is good!), The alternator opposes a couple given. You just have to play on the diameter to get the maximum output speed, and on the intensity to scrape all the potential torque from the wheel without dropping the speed too much! It’s a bit of cooking.

Finally, since your wheel is already made, you will only be able to play on the intensity, and your alternator will not necessarily run at optimal speed.
Anyway, I don't think that the efficiency of an alternator varies enormously depending on the speed ...

Merry Christmas !

(Grrr, I envy all these people who have a stream behind their garden !! : Evil: : Mrgreen: )
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by chatelot16 » 25/12/08, 23:01

the efficiency of a car alternator is not constant in all cases

it is not very good in the car when it is necessary to make 14.5v cost that cost even at low speed: it requires a large current of excitation and saturates the magnetic circuit

when operating at a voltage lower than 12v, it does not saturate and the efficiency is better

it can be interesting to take a large 24v alternator from a truck and use it at reduced power for better performance
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by chatelot16 » 25/12/08, 23:13

the main question is not the alternator but the power of the stream: also on that P = U x I we also know that P = pressure x flow

to have the power in watt you need pressure in N / m2 (pascal) and the flow in m3 / s

to take advantage of the pressure, it would be necessary to pass the flow through a fairly long pipe following the slope of the stream: the pipes must be large enough so that the flow passes without too much pressure drop: at the bottom of the pipe there will be pressure for a turbine

the turbine can be a centrifugal pump used upside down: the advantage of the turbine on the wheel is to operate at higher speed therefore closer to the ideal speed of an alternator

1st question: what is the elevation you can use on your stream

of course if you want to leave the fish with water the dam that sends the water in a pipe does not send everything there but lets a small flow through the stream
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by Olivier22 » 25/12/08, 23:32

You still need a big drop to significantly increase the pressure!
The disadvantage of the turbine is that precisely small fish, it makes mince.
While the impeller using flow, not pressure, wouldn't hurt a tadpole
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