Some time ago I briefly looked into the Aquair online and came away with the impression that it seemed rather expensive.
An axiom applicable to any fluid power scheme is that the lower the head (pressure or velocity), the larger and more costly the turbine for a given power output. Free stream turbines are for the lowest of the low head sites, so the fact that they are costly is no surprise. Still, the lack of pipe and civil works does offset the higher turbine cost to some degree. Free stream propeller turbines are not something that I have any experience with. However, I wonder if it might be possible to reconfigure an electric trolling motor for such an application. These are mass produced, and available at a fairly low cost. They have a submersible permanent magent motor with thrust bearings. Many have a solid state "throttle" control that is probably a simple chopper circuit that could be "turned around" so that the input is the motor/generator and the output is the battery in order to control the turbine speed to optimize power production. The catch is probably the propeller which will have the wrong curvature for turbine ues, and will likely be too small. It will still work at a reduced efficiency I suppose, but a propeller shop should be able to make a custom prop. I don't know, maybe such generators exist for the sailboat market. A little drag on a sail boat to keep the batteries charged up would seem like a fair trade unless you were racing. A quick check of the web shows electric trolling motors from ~ $100 to over $3000. So it shouldn't be hard for someone with a suitable site to try out this idea. Any thoughts from the group? Joe Joseph Hartvigsen Hartvigsen-Hydro 1529 South 400 East Kaysville, UT 84037 USA Micro Hydro components, turgo runners http://h-hydro.com ------------------------ Yahoo! Groups Sponsor --------------------~--> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar. Now with Pop-Up Blocker. Get it for free! http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/FGYolB/TM --------------------------------------------------------------------~-> 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 <*> To visit your group on the web, go to: http://groups.yahoo.com/group/microhydro/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
