----- Original Message -----
From: Lewis Burgess<about:blank>
To: [EMAIL PROTECTED]<about:blank>
Sent: Thursday, August 12, 2004 5:15 PM
Subject: [microhydro] Aquair Submersible Generator
I am a new member interested in work being done to provide
micro-hydropower to off-grid rural communities. I have become familiar
with the use of the various kinds of turbines used for this purpose
(e.g. impulse and reaction) which require specific head measurements.
My current interest is submersible turbines that require only stream
velocity to generate electricity. At the micro-hydropower level, I
have found only the Aquair UW Submersible Generator. Even so, till the
present moment, I have not found it used in any rural electrication
project.
Does anyone know of a project where the Aquair generator was or is
being used to generate electricty to off-grid rural communities? And
what are the pros and cons of using the Aquair or other available
instream or free-flow turbines for this purpose?
Also, being a novice at all of this and knowing little of the field
and existing applications, I wonder why a variety of free-flow
turbines are not available for micro-hydropower uses. It seems to me
that an instream turbine would be more cost effective and less labor
intensive than installing an impulse or reaction turbine. For example,
there is no need for large civil works (weirs, penstocks, tailraces,
etc.). Up scaling would seem to be simpler as well. I imagine that
there must be something problematic about using submersible turbines,
but I am at loss as to why these turbines are have not been developed
and to my knowledge not widely used. Please provide any information
you on why this is so or if I am mistaken, please lift me out of my
ignorance.
Thank you.
Sincerely,
Lewis Burgess
Dear Mr. Burgess,
The Aquair is a great design. But it looses its cost effectiveness as it
increases in size.
By using Permanent magnet generators, the Aquair has very high efficiency and
is fairly cheap. It does not need something to increase the RPM.
The problem is as permanent magnet generators get bigger, the cost increases
almost exponentially. This makes constructing a large version of the Aquair
economically unpractical.
That is where turbines come in, they spin fast to very fast. This allows them
to run cheap higher RPM generators. Once again, no gear multiplication (no
transmission, chain or gears).
The problem comes down to; How do you generate electricity with the flow of a
river, cheaply.
I have been working on that problem for a while and have come up with the
Gravity Wheel. It uses the slow but powerful movement of a river to raise water, to
create head, to run a turbine. This solves the gearing problem (which is expensive and
complicates things) and the generator problem.
If you are interested, please see my site at
http://WildWaterPower.com<about:blank>
This technology is based on the ancient technology of the Persian waterwheel.
Information about that can be found by going to this site
http://www.experimentarium.dk/uk/naturvidenskab_og_teknik/schiolers/<about:blank>
I suggest looking at this site, it is wonderful!
On a final note for hydropower from the flow of a river, it is the weakest
form of hydropower (30% efficiency compared to the 70% of an overshot waterwheel to
90% of a turbine). In order for it to be worth the effort, it must be built on a large
scale. Not Hoover Dam big, but big for small Hydro.
Here in America, I see no future for my design. With the environmental and
government regulatory situation as it is, I do not think one will ever be built in
this country. That is why my patent is only for the United States, I do not want to
stand in a developing countries way.
Sincerely,
Dennis
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