First time hydro

[dblais]

Hi,

I'm new in this world. I read a lot this week  ...  At first I wanted to make a wind turbine (small wind of 7-12mph), but I think with my little creek is better to make a hydro system?

I have a small creek that I have takken mesure.
Width 3.75 ft.
Depth 4 inches (0.33 feet)
Head: 3.3 feet (dam to do)
An object that floats a distance of 30 feet in 14 seconds.

3.75f * 0.33f * 30f/14s = 2.68 cubic feet per second
1 cubic foot = 7.481 gallons / second

7.481 * 2.68 = 20.24 gallons / s or 1202.3 gallons / minute

For my 1200 gpm is a lot of water for this small creek, i dont believe, is that correct?


1202.3gpm * 3.3head *.18 = 404.86 watt possible..

Cut in half to be safe (200w)

According to the width of the creek and the little head, I think the best thing to do is an overshot waterwheel or better backshot? I Will do a PMA generator 2 disk of 12 magnet or 1 disk of 24 magnet. Small magnet of (disk 1 * 3 / 8 inch), maybe 24 volt.

Do you have any suggestion about the best structure (turbine, waterwheel, other) size, generator ?

Here the creek
http://www.youtube.com/watch?v=S3mvIZMAzC4

Thank you!
David

[dblais]

Here a picture of the stream.



Do you have any idea?

[12AX7]

Hi..

Looks like a nice stream,  but COLD.

Lots of snow but most of the stream is still open and flowing.   Does it flow year round or will it freeze over?

[dblais]

I think it will be ok for the stream because there is a good flow. But i think it can be a problem if i use a big waterwheel... Do you think something like the picohydro "http://www.best-solar-energy.com/renewable/pico-hydro-water-turbines-can-generate-300-or-500-w-of-power/" can be better for the winter?

[12AX7]

Hi

I live along side a small river,  wider,deeper and I believe flows faster than the video you posted,  and it does freeze in the winter.  Places where the current is much faster also freezes. 

I don't know where you are,  but judging by the amount of snow I'll bet that your stream will freeze over, although water will probably continue to flow under the ice.

4 inch depth isn't much, is it possible to put in a small dam?

[hydrosun]

Calculating the gpm , is the depth average 4 inches or is that the deepest spot? The speed of the water is fastest on the surface in the middle of the stream, so the average is a bit lower than calculated. The gpm times head is divided by 10 for a 50% efficient system. So the 200 watts number may be a bit high. A turbine like the ESd would fit your stream nicely. The lower cost PowerPal would fit but with more upkeep. A homemade cross-flow like featured on this site would the simplest and fairly efficient.
Chris

[dblais]

Thank you for yours reply!

4 inch is the average. I can do a dam of 3 feet easily. I can reduct the width to have a bigger flow.

I think ESd turbine will need a bigger head (5-10 feets) to have a advantage over the complexity.

I think cross-flow can be a problem with the cold? May be I can put the flow and the crossflow inside a pipe to be sure it will not freeze?  Something like this : http://www.scribd.com/doc/37240468/Crossflow-Construction-Guide


Do you think if a put a draft tube after it will be really more efficient?

Thank you
David

[hydrosun]

The reason I mentioned the ESD low head(propeller)  and crossflow is they will turn faster than a three foot overshot wheel. The slower speed wheel will need more gearing or  windings of  wire to get the speed needed to make a given voltage.  There is a discussion of the advantages and disadvantages on putting gearing on a wind generator in another thread. In hydro you have the third option of changing the style of turbine to achieve the higher speed. I don't know if it has any more vulnerability to freezing than the open wheel. A draft tube allows you to get all the fall available. With an overshot you have to have it raised enough to avoid the drag of the tail water if water levels rise. So you lose some of your effective head.
You haven't mentioned what system voltage you will be using and how long the wire from the stream to the batteries will be. That will determine the best voltage your turbine needs to produce and the windings and magnets.

[dblais]

Thank for the reply ,

ESD and crosslow is not the same thing? http://en.wikipedia.org/wiki/Cross-flow_turbine

When you talk about ESD low head you mean "Banki turbine"?

What is the big difference between the ESD and a Overshot waterwheel? The water that go inside the wheel to the other side?

The dam will be at 50 feets of the battery. For the voltage i'm not sure. My electronic work at 12 volt. But i think it's more efficient if i do a generator of 24volt who charge two 12volt battery.


Lot of question 

Thank you!
David

[hydrosun]

The ESD lowhead unit is a propeller in a vertical pipe. It turns the fastest of all types of turbines. Check it out at microhydro.com   A cross flow (or Banki)  has horizontal paddle blades with the water hitting one side and flowing through it to hit a blade on the way out.  It's speed is determined by it's diameter.  It can be made wider to use more water but keep the same diameter. Both types can use a draft tube to use the drop available after leaving the turbine.
An overshot is the same size as your head, so it's diameter is larger and turns slower. It has to turn in the air so it can't use all the head. There is another thread in this hydro section that has a picture of a overshot with lots of gearing up to turn a generator. Since you are relatively close to the batteries and less than 200 watts you could produce at 12 volts and not need as high of rpm.
Chris

[thirteen]

Is there alot of junk that comes down when it rains or spring runoff? You may need to make a catch system for the junk or go upstream and clean up the stuff in the creek.  A small dam would help. To me how cold it gets where you are will be a big question. At below zero water freezes quickly on exposed areas. Is it in a spawning area for fish? Just wondering.

[dblais]

I think i will go with a Banki. More simple to do homemade... But i think i will need to put a gearing. What is the best chain, gear or vbelt ?

Is there alot of junk that comes down when it rains or spring runoff? You may need to make a catch system for the junk or go upstream and clean up the stuff in the creek.  A small dam would help. To me how cold it gets where you are will be a big question. At below zero water freezes quickly on exposed areas. Is it in a spawning area for fish? Just wondering.

For the junk, i will try to put this in a box, less dangerous to freeze and less juke.
No fish there.

David