Good point about the pressure. I'll have to check into that. --- In [email protected], Eilrem Fernandez <[EMAIL PROTECTED]> wrote: > 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. 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] > > > > SPONSORED LINKS > Energy management Energy gels Energy conservation home Energy savings Energy Energy efficiency > > --------------------------------- > YAHOO! GROUPS LINKS > > > Visit your group "microhydro" on the web. > > To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. > > > --------------------------------- > > > > __________________________________________________ > 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]
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