Thank you all for your responses to my request. Nando has quite correctly asked for the amount of power I was considering. I was thinking ideally of 30kW installed capacity where actual continuous power use initially would be less than half of that or 15kW. From what I have read this would be enough to provide residential, public building and street lighting for at least one hundred households as well as other applications for economic and health development such as water pumping, milling, battery charging, water purification, refrigeration for vaccines, medicines, perishable foods, etc.
The type of rural communities I had in mind would be upland or in in mountainous regions having streams at least one meter in depth, at least 1.5 meters wide with stream velocities of at least 2.7 - 4.1 mps. This dimensions would allow for increased rotor size, additional installations and space enough for constructing an instream structure that can constrict stream flow and increase stream velocity. The stream velocity is the minimum and recommended velocities necessary for the operation of the Aquair generator. Steve provided info on 2kW electricity generating free-flow turbines Garman Turbines and Darrieus Water Current Turbine used in Egypt, the Sudan and elsewhere. Stream velocities go up 2 mps. The Garman turbine needs a stream with a depth of more than 1 meter (1.75 meters?). See - http://ourworld.compuserve.com/homepages/throptonenergy/homepage.htm - Garman Turbines http://www.althydrosolutions.com/products.html - Darrieus Water Current Turbine These turbines, including the Aquair, do not generate enough electricity to meet a 15kW requirement. It seems that one would have to install 10 or 12 turbines to get 15kW for continuous use. This seems to be one problem for electrifying a rural community of 80 to 100 households beyond a 60 watt light bulb per residence. So does everyone agree, as Dennis pointed out, that increasing the capacity of Aquair-like generator is very costly and that this is the main reason why it is not used widely for power generation for rural communities? Does this also apply to the Garman and Darrieus turbines? And Dennis is there any more information you can provide on the Gravity wheel? How much power does it generate? What are the site specifications? Cost? Finally, given the information above, is it feasible, given today's technology, to design a free-flow or submersible turbine that can generate 25kW and still be small enough to fit the site specification described above? I still have a glimmer of hope. Yours, Lewis Steve Gregory wrote: > Greetings Lewis, > there are a number of water current turbines on the market presently. The > reason that they are not well known is there limited usefulness. the river > speed has to be fairly high in order to be worth putting out the money for > purchase. > will provide you with some alternative sources though. > http://ourworld.compuserve.com/homepages/throptonenergy/homepage.htm this is > perhaps the best one for more rural sites as it would be the cheapest and is > used alot in Africa. > A newer model of the one shown on the site below is available now and pics > will be up shortly. http://www.althyrosolutions.com > bye for now, > steve gregory > >>-----Original Message----- >>From: WINDSTREAM POWER SYSTEMS INCORPORATED >>[mailto:[EMAIL PROTECTED] >>Sent: Thursday, August 12, 2004 6:05 PM >>To: [EMAIL PROTECTED] >>Subject: Re: [microhydro] Aquair Submersible Generator >> >> >>Try www.verdantpower.com >> >>Engineering Department >>Windstream Power Systems Incorporated >>PO Box 1604, Burlington, VT 05402-1604 >>Tel 802 658 0075 Fax 802 658 1098 >>Email [EMAIL PROTECTED] >>Website - www.windstreampower.com >> ----- Original Message ----- >> From: Lewis Burgess >> To: [EMAIL PROTECTED] >> 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 ------------------------ Yahoo! Groups Sponsor --------------------~--> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar. Now with Pop-Up Blocker. 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