Posted by DJ on March 17, 2005, 3:01 pm
Gents,
Looking for a microhydro generator dealer/manufacturer. North American,
Canadian if possible.
Looking for a turbine that would output something like 5kw. I've seen
the 1kw ones, but am having difficulty finding the larger units.
Parameters to include a total head of 3 meters, but huge volume, year
round. Worst flow year was about 300 cubic meters per second, the
entire span of the small (in height) waterfall.
Thanks,
DJ
Posted by Eric Sears on March 17, 2005, 3:42 am
Just a couple of comments -
1. Microhydro?? I wonder if your flow is correct? I know you said a
huge flow - but our largest local river (Wairau) draining 1000's of
square km doesn't have that sort of minimum flow, You have something
like 9 megawatts theoretical there, and could potentially put 4 or 5
megawatts into the grid - though of course, you may not be near the
grid. (not 300 litres/sec?)
2. Assuming however that whatever the flow, there is plenty to get the
5 kw that you want, the ideal turbine would be a Kaplan. We have
homebrewed one of these to run on a 5 m head, though with only about
10 litres per sec - this has been used to power my holiday home for
the last 14 years. There are plenty of standard 5kw generators
available off the shelf. The advantage of the Kaplan is that you can
have the turbine and generator well above the water level.
3. The alternative turbine would be a Crossflow (also known as a
Banki) - do a search for "Shoal Creek Power & Light" (or just SCPL),
to get a good design. As far as I know these are still produced by
Ossberger and others - also some American companies.
Cheers
Eric Sears
>Gents,
>Looking for a microhydro generator dealer/manufacturer. North American,
>Canadian if possible.
>Looking for a turbine that would output something like 5kw. I've seen
>the 1kw ones, but am having difficulty finding the larger units.
>Parameters to include a total head of 3 meters, but huge volume, year
>round. Worst flow year was about 300 cubic meters per second, the
>entire span of the small (in height) waterfall.
>Thanks,
>DJ
Posted by DJ on March 17, 2005, 5:08 pm
Eric Sears wrote:
> Just a couple of comments -
> 1. Microhydro?? I wonder if your flow is correct? I know you said a
> huge flow - but our largest local river (Wairau) draining 1000's of
> square km doesn't have that sort of minimum flow, You have something
> like 9 megawatts theoretical there, and could potentially put 4 or 5
> megawatts into the grid - though of course, you may not be near the
> grid. (not 300 litres/sec?)
The thing is, it is a client property, and they do not want to disrupt
either the flow or the aesthetics of the waterfall (and yes, those
numbers are correct, verified by the local hydro authority). The client
only wants enough to run a small home, hence the request for a 5kw
unit. That should provide sufficient generation for even a normal home.
My other alternative is multiple 1kw units, which has some attraction,
from the "don't put all your eggs in one basket" viewpoint. So, best
case, a diversion pipe system I can "hide in the woods", yeah.
> 2. Assuming however that whatever the flow, there is plenty to get
the
> 5 kw that you want, the ideal turbine would be a Kaplan. We have
> homebrewed one of these to run on a 5 m head, though with only about
> 10 litres per sec - this has been used to power my holiday home for
> the last 14 years. There are plenty of standard 5kw generators
> available off the shelf. The advantage of the Kaplan is that you can
> have the turbine and generator well above the water level.
Ok, that might be nice, I'look into that one!
> 3. The alternative turbine would be a Crossflow (also known as a
> Banki) - do a search for "Shoal Creek Power & Light" (or just SCPL),
> to get a good design. As far as I know these are still produced by
> Ossberger and others - also some American companies.
I will do that, thanks!
DJ
Posted by Eric Sears on March 17, 2005, 6:30 pm
>The thing is, it is a client property, and they do not want to disrupt
>either the flow or the aesthetics of the waterfall (and yes, those
>numbers are correct, verified by the local hydro authority). The client
>only wants enough to run a small home, hence the request for a 5kw
>unit. That should provide sufficient generation for even a normal home.
>My other alternative is multiple 1kw units, which has some attraction,
>from the "don't put all your eggs in one basket" viewpoint. So, best
>case, a diversion pipe system I can "hide in the woods", yeah.
Hmm - well I'm still trying to picture this river with 300 cub metres
per sec. Flowing at 2 m per sec it would need to be 100 metres wide
and 1.5 metres deep (that's its low flow!). I should be surprised if
the river bed were less than 200 to 300 meters wide.
Is that a fair description - or have you not seen it?
(Unless the river is very steep, which I doubt, or you would have much
more than 3 m of fall)
Anyway, assuming there is at least the required 400 litres per second
that you will need to generate about 5 kw at 3 meters head, you will
clearly have to disrupt something to draw the amount of water needed.
A 10 to12 inch nozzle under 3 meters of head will pass about this
amount of water, so you will need pipes of probably at least 24 inch
diameter, even if they are faily short. You won't be using any 2 inch
alkathene with such a low head for that sort of power!
For five 1kw units you would need about 8 inch diameter pipe feeding
each them, but I don't know what sort of units you would have in mind.
Each would be drawing about 80 litres per second.
Overall efficiency is unlikely to be more than 50% for that head.
Presumably finance is no great object - I can't imagine any 5 kw
system for this head being low cost! - unless you can make your own
crossflow turbine (been there, done that also).
Hope it works out.
Eric Sears
Posted by Ecnerwal on March 18, 2005, 9:06 am
I've never looked all that hard at them, since the only hydro I might
hope to have is very micro (gravity well overflow), but I wonder if this
might be a place where the "propellor mounted on the bottom of the
streambed" style of tubine might be best. Not good for getting all the
power available, but should be good for low disruption of the stream
while extracting some power. Ducting it would probably make it less
efficient, but also less prone to damage (sticks, ice, etc).
Mind you, I've never heard of anyone actually using this setup, just
seen it advertised occasionally. Has obvious disadvantages WRT ease of
service for the generator head.
--
Cats, Coffee, Chocolate...vices to live by
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>Looking for a microhydro generator dealer/manufacturer. North American,
>Canadian if possible.
>Looking for a turbine that would output something like 5kw. I've seen
>the 1kw ones, but am having difficulty finding the larger units.
>Parameters to include a total head of 3 meters, but huge volume, year
>round. Worst flow year was about 300 cubic meters per second, the
>entire span of the small (in height) waterfall.
>Thanks,
>DJ