Low-Flow Hydro

Kingfish

Kingfish

100 MW
Joined
Feb 3, 2010
Messages
4,064
Location
Redmond, WA-USA, Earth, Sol, Orion–Cygnus Arm, Mil
Greetings –

We have a small stream on our remote property; it’s about 2-3 feet wide by a foot deep and runs between gentle & quick through the summer. The drop is gentle across the acreage; however there are a couple of spots where the stream drops about 3 feet over twice that distance making it perfect for a Pelton or Water Wheel. We’re not out to power the neighborhood; just scavenge a trickle-charge 24/7, complementing the existing solar and reducing the dependence of running the generator.

Just a quick dig and I found this:


The part list suggests:

  • Wheel $100
    Alternator Model DC-540 $269
    Rectifier $29
    Charge Controller $99
    Pulleys and other mounting equipment ??
    Base cost: ~$500 + small hardware
I’m pretty sure the flow of the stream is enough to provide the trickle and is also not high enough to overrun the alternator. The neat thing about that particular model is that the stator can be replaced or upgraded.

I’m just curious is anyone else has tried this, and if so what equipment was used, size of wheel, etc. My thinking is that this would make for a great Father’s Day present to my Pa. We’ve been tinkering with trying to capture that stream for many years with Okie technology – and it ain’t workin’ fer us. It’s time to fish or cut bait. :wink:

Insights welcomed. KF
 
Wait on spending money, I'll be back in a couple hours...if I don't get back with a comprehensive post, most of my info was gleaned from the hydro section of otherpower.com

http://fieldlines.com/board/index.php?PHPSESSID=0522aef4ac99b6238dd700429222b5c1&board=7.0

one link of many about well-researched low-head hydro.
http://fieldlines.com/board/index.p...00429222b5c1&topic=131102.msg855969#msg855969

Also research Poncelet water wheel.
http://www.waterwheelfactory.com/history.htm

For very low-head flow, sometimes a few watts can be harvested with a Banki crossflow. The water passes through the blades twice.
images
 
Consider these guys:
http://www.rpc.com.au/catalog/hydro-power-c-2_225.html

Rainbow have been around the longest here in Oz, and they live, eat, breathe renewable energy. They are just so passionate about it I couldn't recommend them enough. Of course getting stuff over to the states is going to be a bit tough, they are a wealth of knowledge on all sorts of stuff, especially micro-hydro. Peter Van Der Wyck (aka Peter Pedals) build the first micro hydro unit and it manages to crank out a little over 500 W under ideal conditions. Enough to keep a battery topped up at least.
 
I’ve looked these bits of information over and it spells out “more cost” than the original idea of using a water wheel. That said, I see that the over-the-top method has the better efficiency, although this will require a smaller wheel – probably 1 meter/3 feet diameter. Just as well; we’ll need to stow it for the winter anyway. Good stuff to know though if one could develop more head.

When I had a tree farm, there was 110 feet difference between the high-low points and had considered using rain water runoff from the roof directed to a pond, then exiting through a long penstock. The nozzle would have been 2-3 inches in diameter. After the cost analysis it was deemed too expensive at the time for a Pelton wheel: No enough rain to support the system. It’s Seattle and we don’t get enough rain? However the systems listed in the links you guys provided says it would have worked with today’s tech. :)

ADDENDUM: Found this interesting old manual on the Overshot Wheel that also discusses Undershot design, simple dams, and flow measurements. :)

Testing the water, KF
 
Having slept on this, I have more questions.
  • With regards to the Alternator Model DC-540, could I use a hub motor or outrigger instead?
  • Is there something special aside from the wind that makes this alternator special?

I just checked with my Pa and he says the stream is about 1 foot wide with 18-24” of drop: It’s going to have to be an Undershot wheel if we do this.

Wheels turning, KF
 
Kingfish said:
Having slept on this, I have more questions.
  • With regards to the Alternator Model DC-540, could I use a hub motor or outrigger instead?
  • Is there something special aside from the wind that makes this alternator special?

I just checked with my Pa and he says the stream is about 1 foot wide with 18-24” of drop: It’s going to have to be an Undershot wheel if we do this.

Wheels turning, KF
Click to expand...

I found this which is a waterwheel installation about the size you are contemplating, and using the same alternator. It seems to be used mainly because it can produce decent volts at low revs. The wheel itself only does 10 rpm, so a lot of gearing up is needed. A slow-wind direct drive hub motor might well be an option.
 
Thanks JennyB – that is an interesting read that nearly matches our application! It is quite inspiring to consider we could get a bit more than hoped. :D

I found these other sources as well:

Treading water, KF
 
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