GI pipes are mild steel pipe coated with zinc, while BI means black iron or uncoated mild steel pipe. High pressure PVC pipes are usually rated at 100psi, equivalent to a maximum of 70m head. However, this just left you a small factor of safety. An accidental blockage of the nozzle or too rapid closure could cause the pipes to burst. Your storage capacity is 8.8kWhr (8V x 1100Ah). If you're planning to use the microhydro only for battery charging, you can even use a 2" diameter GI pipe and still be capable of generating 300W of power @ 1L/s, equivalent to 7.2kWhr of charge everyday (about 4x the average daily output of your PV array).
thomas_a_phillips <[EMAIL PROTECTED]> wrote: Judging flow is the problem, since it varies so much. The spillway is about 10 feet across and right this minute is running a foot deep. (Hurricane Katrina just blew by.) All winter it runs way more than will fill a 4" pipe. But as Summer comes on, it can dry up completely, the inflow that is. Although this summer has been wetter than usual. Not sure what GI or BI pipe is, I'm planning to use 4" PVC in 20 ft lengths. The water where I plan to locate the intake is 4' deep, So I thought I'd set the pipe with a strainer on the end inside a screened box with the pipe about a foot below the surface. We get a lot of leaves, sticks and other organic matter in the 1.25 acer pond. My PV array is on an active tracker and produces a peak of 20.5 amps at 24 VDC. I use recycled railroad locomotive batteries 6 x 8v for 24 V and supposed to be 1100 amp hours total. Have a Trace SW4024 inverter, C40 controler and Trimetric meter. Tom --- In [email protected], Eilrem Fernandez <[EMAIL PROTECTED]> wrote: > Hi Tom, > > I'm assuming that you're using GI or BI pipes since the maximum pressure at the bottom is about 85psi. Your penstock could handle up to 12L/s flow rate with reasonable efficiency. > > For proper operation, the intake only requires a minimum depth of submergence 3x its diameter, theoretically 12" in your case, which makes your plan (4ft) more than sufficient. However, if you could immerse your intake deeper, you can use the pond as water storage during the dry weather. > > You can operate the system at full power (around 5kW @12L/s for pelton runners, or 3-4kW for crossflow runners) when water availability is sufficient. If the system is outfitted with multiple nozzles or with a spear valve, you can just adjust the flow rate to match what is available. > > However, generators and alternators are notoriously inefficient when operating at partial capacity. So if you have sufficient water storage capacity in your pond, you can operate your system for a few hours then wait for the pond to fill up before using it again. > > May I know your battery bank capacity and the total watt-peak capacity of the PV array? Are you planning to use your microhydro just for battery charging or have plans for other applications? Are you using your system as a hybrid system? Are you planning to fabricate your own turbine? Such info is also relevant in deciding what is best for your microhydro system. > > Eilrem > > thomas_a_phillips <[EMAIL PROTECTED]> wrote: > To introduce myself, our OTG Solar home is located on the Cumberland > Plateau, north of Chattanooga. We use Solar electric, propane and > diesel with some wood for energy needs. Our home sits on a bluff > that rises 150' above a raveen with a creek. We have a 1 acre pond > up on the bluff that is fed by a wet weather stream that runs 8 or > nine (winter)months. The out flow from the pond goes over the bluff > to the creek below. > > I have surveyed a route for a 4" penstock from the spillway over to > the bluff and down the slope to a suitable turbine location. Total > length of the penstock will be around 800 ft. The Penstock will be > buried from the pond to the edge of the bluff. The slope is too > rocky to bury it from there to the turbine site, the last 200'. > Difficulties will be the length of the penstock, the fact that it > traverses a dip before droping over the bluff, the need for concrete > thrust and slider blocks on the steep slope, and the distance of the > turbine from the house, probably about 600'. > > I have two questions I'd like some input on. One, I think I can > place the intake for the penstock out in about 4 feet of water in > the pond away from the spill way. Is that a good plan? > > And two, It is a wet weather stream that drains about 50 acres. This > year has been unusualy wet, so the stream has almost not stopped > running. But other years we have seen little or no flow in July, > August and September. (Of course the solar panels crank then). How > are these periods of intermittant flow handled? Does it require > constant adjustment, or do you just shut it down till you have > sufficient flow? > > Thanks for your input and glad I found this site, > > Tom > > > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > > [Non-text portions of this message have been removed] 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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