# Hydroelectric project (small drop and low flow)

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## Hydroelectric project (small drop and low flow)

Hello everyone,
I am new to the forum.

I plan to place a hydroelectric collection device to complete the electrical installation of our home,
in isolated site, currently equipped with photo solar panels.
Our autonomy in electric energy is very close to being reached, too, a device even of very weak power would be enough.
We have on site a body of water about 4 500 m3, fed by a source and a succession of small bodies of water upstream, installed in the old bed of a small stream (ru?).
The overflow of the body of water then flows into a ru, through a nozzle.
Having this resource in front of us, we wonder if we can not recover this hydraulic force, which theoretically should be of higher flow in winter; period during which the sun can be deficient.

I would like to send you these pictures for your opinion on the feasibility and / or the desirability of any project.
I tried to calculate the flow at the outlet of the nozzle, we arrive at about 0,42 l / s is 1,512 m3 / h (this is a rough estimate, the flow in winter would be stronger). The height of fall would be about 4 m.

I had thought of the SETUR Vortex Turbine device, which by placing it just before the overflow would take advantage of the "swirl" effect; but maybe there is another technical option at the nozzle outlet just as profitable?

If anyone can tell me if the conditions are right to create the opportunity to place any device, or if on the contrary the production would be really too small to try anything.

Knowing, once again, that a supplement even of about +/- 100 W (even 50W X 24 = 1 Wh / d -> that would be enough to spend the few days without solar production).

overflow and dike.JPG (175.05 KIO) Viewed 8795 times

nozzle 1.JPG (271.8 KIO) Accessed 8795 times

nozzle 2.JPG (448.49 KIO) Accessed 8795 times

nozzle 3.JPG (238.98 KIO) Accessed 8795 times
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Bardal
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## Re: Hydroelectric project

With a flow rate of 0,42 l / s and an altitude difference of 4 m, the potentially available energy is small, since it is equal to 0,42x10x4 = 17 W, which theoretically gives 400 Wh per day. You can hope to recover effectively three quarters, for an expense that remains to quantify, with a very simple arrangement if I believe your photos.

We are very far from what you expect; it is certainly possible, at the cost of a certain complexity, to increase the power for a short period of time, but that will not change the quantity of energy produced per day; besides, you will struggle to find adequate material in these powers.
You should either increase the fall, if it is possible, or increase the flow (in winter maybe) ...
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Christophe
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## Re: Hydroelectric project

No better bardal
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Christophe
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## Re: Hydroelectric project (small drop and low flow)

A suggestion all the same because 4500 m3 is not nothing.

By lowering the level, it is possible that the flows that feed the pond may increase ...

If we assume (theoretically) a complete emptying of the pond, this makes an energy potential of: 4 500 000 * 10 * 4 = 180 MJ is 50 kWh.

Of course the complete emptying is not possible but 1 / 10 daily drain that would be compensated that makes 5 kWh, 4 electric kWh, this can become interesting... of course it has to be compensated! It all depends on upstream flows and the exact situation ... and the budget of this project ...

Can you take pictures from upstream?
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## Re: Hydroelectric project

bardal wrote:With a flow rate of 0,42 l / s and an altitude difference of 4 m, the potentially available energy is small, since it is equal to 0,42x10x4 = 17 W, which theoretically gives 400 Wh per day. You can hope to recover effectively three quarters, for an expense that remains to quantify, with a very simple arrangement if I believe your photos.

We are very far from what you expect; it is certainly possible, at the cost of a certain complexity, to increase the power for a short period of time, but that will not change the quantity of energy produced per day; besides, you will struggle to find adequate material in these powers.
You should either increase the fall, if it is possible, or increase the flow (in winter maybe) ...

I would like to say that the estimate should be re-evaluated to a large extent, we are currently in a period of low water, during which time we will not rely on this device at all to supply us with energy (we are already largely overproduction with our PV).
I should have woken up earlier;)
Taking this context into account, in winter, the rare days when my solar production would be at 0 kW, even if I manage to recover 0,5 kWh / d (we can largely rely on this hypothesis, I elaborate below) -> this may be sufficient to avoid turning on the generator.
Provided, of course, that the device is not expensive.
What do you mean by "very simple arrangement"?
I'm going to struggle to find material adapted to such a low power, but will I find?
Impossible to touch the fall on the other hand.

Thank you for your help (I continue below).
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## Re: Hydroelectric project (small drop and low flow)

Christophe wrote:A suggestion all the same because 4500 m3 is not nothing.

By lowering the level, it is possible that the flows that feed the pond may increase ...

If we assume (theoretically) a complete emptying of the pond, this makes an energy potential of: 4 500 000 * 10 * 4 = 180 MJ is 50 kWh.

Of course the complete emptying is not possible but 1 / 10 daily drain that would be compensated that makes 5 kWh, 4 electric kWh, this can become interesting... of course it has to be compensated! It all depends on upstream flows and the exact situation ... and the budget of this project ...

Can you take pictures from upstream?

Thank you also for taking time for my project.
I think as said above that we can rely on a higher flow in winter (see photo below); and, I've just thought about it, I can also redirect some of my EP for direct rejection in the pond or water upstream which will induce a reinforced flow.
I have placed a photo showing the junction of the nozzles between the "pond" and the pond, we see that I raised the junction elbow upwards to keep a sufficient level of the pond (above the level of its overfull).
To illustrate a level of flow much higher in winter, if I hold the piece in this position I flood the ground, because the flow is too constrained. I must at least lower the elbow, or sometimes even reinsert in direct connection with the nozzle (I can not wait to estimate the flow again in this configuration).

nozzle inter.JPG (220.23 Kio) Accessed 8712 times

upstream stretch of water.JPG (205.36 KIO) Viewed 8712 times

body of water pcpal.JPG (172.56 KIO) Viewed 8712 times
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Bardal
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## Re: Hydroelectric project

I would like to say that the estimate should be re-evaluated to a large extent, we are currently in a period of low water, during which time we will not rely on this device at all to supply us with energy (we are already largely overproduction with our PV).
I should have woken up earlier;)
Taking this context into account, in winter, the rare days when my solar production would be at 0 kW, even if I manage to recover 0,5 kWh / d (we can largely rely on this hypothesis, I elaborate below) -> this may be sufficient to avoid turning on the generator.
Provided, of course, that the device is not expensive.
What do you mean by "very simple arrangement"?
I'm going to struggle to find material adapted to such a low power, but will I find?
Impossible to touch the fall on the other hand.

Thank you for your help (I continue below).

The very simple arrangement consists in placing in the drain a device including the alternator, the turbine and a pipe of appropriate diameter 4 m long; this type of turbine is complete in powers of 0,5 kW and more; it's very simple to set up (a few pegs) and costs less than 2000 € (I had seen a few years ago at 4-500 €, they seem to have disappeared from the market); on the other hand, in a range of about ten watts, I have never seen. But this may exist (modeling, marine pleasure ...).

If it can not be found, all that remains is to tinker with something; in fact it's very simple: a propeller in a pipe, connected to a small regulated alternator; within reach of a careful amateur, but the alternator and propeller do not tinker, and the necessary optimization of the various elements and their interaction may be long and tedious.

Two examples of low power Kaplan turbine (but too strong for you):
https://www.turbiwatt.com/fr/second-men ... rbine.html
https://www.energiedouce.com/hydro-turb ... 02527.html
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## Re: Hydroelectric project

The very simple arrangement consists in placing in the drain a device including the alternator, the turbine and a pipe of appropriate diameter 4 m long; this type of turbine is complete in powers of 0,5 kW and more; it's very simple to set up (a few pegs) and costs less than 2000 € (I had seen a few years ago at 4-500 €, they seem to have disappeared from the market); on the other hand, in a range of about ten watts, I have never seen. But this may exist (modeling, marine pleasure ...).

If it can not be found, all that remains is to tinker with something; in fact it's very simple: a propeller in a pipe, connected to a small regulated alternator; within reach of a careful amateur, but the alternator and propeller do not tinker, and the necessary optimization of the various elements and their interaction may be long and tedious.

Two examples of low power Kaplan turbine (but too strong for you):
https://www.turbiwatt.com/fr/second-men ... rbine.html
https://www.energiedouce.com/hydro-turb ... 02527.html

Excuse me, I do not understand if it is necessary to place the turbine at the exit of the overflow (at the bottom of the nozzle) or at the entry (at the top of the nozzle)?
and according to you can I leave the nozzle as it is or should I do otherwise?
Thank you
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Bardal
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## Re: Hydroelectric project (small drop and low flow)

Exit or entry of the nozzle, it does not matter (in theory) since the water is incompressible, its speed is the same at the top and bottom.

As to whether the nozzle can be left in the state, I have no idea of ​​the condition of this nozzle; the only thing I know is the elevation of 4 m; in this case, whether the pipe is straight or bent does not matter either, the only important point being the height difference.

The most critical points will obviously be, not these basely "earthwork" questions, easy to settle, but the search for an alternator of such low power and the associated propeller; this is what is critical, and not easy to resolve.

You should start by evaluating the flow in winter, and therefore the potential power of your fall ...
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izentrop
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## Re: Hydroelectric project (small drop and low flow)

bardal wrote:Exit or entry of the nozzle, it does not matter (in theory) since the water is incompressible, its speed is the same at the top and bottom.
If the turbine is placed at the outlet of the high basin, the potential energy will be lower than 4 meters lower.

The 4 m drop are well between the bottom of the high basin and the top of the lower basin?
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