ERIC: I need to contest your remark.
It is quite practical and it is being done in several countries right now, Africa, South America ( Colombia), etc. Also there are systems for in River systems that can generate may Kilowatts , like Underwater Electric Kite that can generate around 60 KW.. 2 Knots can produce energy, one needs to remember that the energy in a moving river like in the wind mills the power goes to the cube of the fluid velocity. There are systems to generate electricity, and pump water, including the raising the water to higher levels, up to about 30 PSI ( I am not sure but it could be higher). There is a fellow in Guatemala that has one for water ( raises water to 15 meters total to a 2 or 3 cubic meter tank) and another for electricity generation ( 400 watts ) for a small resort area he has. There are different systems, some are free flowing like the ones you commented and others are dual contra-rotating propellers and some are encased and with restricted forms to increase the water velocity, some times more than 100 %. One that, I know that is under test, has a new form that increases the water velocity to about 150 - 200 % with augmenter rings. Another one that is being tested in Peru ( under government contracts) has a new type of form. The inventor, Jurgen Diederich ( [EMAIL PROTECTED] ) call it THE CONVEYOR TYPE WATER CURRENT GENERATOR, he has a patent. A careful search could give you a workable unit, like a 400 watts for a daily production of 9.6 KWH Regards Nando ----- Original Message ----- From: "Eric Youngren" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, September 21, 2005 9:12 PM Subject: RE: [microhydro] river electricity? > While maybe theoretically possible, this is not practical. The only > practical way to extract energy from this type of very low head, high flow > river is to dam the river and channel the water through large turbines. > > An open channel paddle wheel or propeller as you suggest would need to be > HUGE to generate truly useable power. Especially at 2 knots. If the > current was 5 or 6 knots, it might be worth an experiment if you are a > skilled fabricator and dedicated tinkerer. The slow current at 2 knots > just doesn't have that much energy density, so your blades would need to > be > quite large, and then you have to find a way to mount these blades on a > hub > or shaft of some kind to spin this contraption, and then you'd have to use > gears or belts to get the rpms up to the speed to drive a generator. > > Better to save the effort and use your money to buy PV panels. > > There are folks doing current turbines out there. Do a search for "Marine > Current Turbines" or "Gorlov Turbines". But you'll find that all of the > projects underway are using a minimum of 4 knots, and likely in the 8 to > 10 > knot range. As the speed of the current increases, the power available > increases in a non-linear manner (I believe it is to the cube of the > velocity) So a 4 knot current has substantially more than twice as much > energy as a 2 knot current. > > Eric > > > -----Original Message----- > From: [email protected] [mailto:[EMAIL PROTECTED] On > Behalf Of aviodont > Sent: Wednesday, September 21, 2005 4:18 PM > To: [email protected] > Subject: [microhydro] river electricity? > > Newbie here... so bear with me! Can someone tell me if it is > possible to generate enough electricity for an avg household by > inserting some sort of propellor into a river that is about 200-300 > feet wide with a flow of 2 kts? If it is possible, can you point me > in the right direction? If not entirely possible, how much > electricity could be expected to be produced. Thanks in advance! > > > > > > > > Does your company feature in the microhydro business directory at > http://microhydropower.net/directory ? If not, please register free of > charge and be exposed to the microhydro community world wide! > > NOTE: The advertisements in this email are added by Yahoogroups who > provides > us with free email group services. The microhydro-group does not endorse > products or support the advertisements in any way. > > More information on micro hydropower at http://microhydropower.net > > To unsubscribe: send empty message to > [EMAIL PROTECTED] > > Yahoo! Groups Links > > > > > > > > > > > > > > Does your company feature in the microhydro business directory at > http://microhydropower.net/directory ? If not, please register free of > charge and be exposed to the microhydro community world wide! > > NOTE: The advertisements in this email are added by Yahoogroups who > provides us with free email group services. 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