3/4 inch water turbine

[Tugger]

I have a hypothetical question for the group...
Lets say i accidenately dug up a couple pipes on my property...
One of the pipes has an inside diameter of 3/4 inch and produces water at a constant 60-65 psi indefinately..
The other pipe is about 4 inches and will take all water produced from the 3/4 inch pipe away....
How would one figure out the electrical power potential from such a HYPOTHETICAL situation?
Cheers
Tug

[mbryner]

Equation often used in microhydro books is:

Average watts produced = Flow (in gpm) x Head (in feet) / 10.     This assumes average efficiency in turbine, wiring, etc.

and 1 psi = 2.3 feet of head

3/4 inch pipe is only about the size of a garden hose, so you won't get high volume (gpm) before the pressure loss is too high.  This depends on the length of the 3/4" pipe from where it comes off some larger pipe.   But here's a quick number I found on the internet:  at 9.4 gpm, there is a 10 psi drop every 100 ft in a 3/4 in pipe (think is was for iron pipe though, PVC probably different, but you get the picture).

Therefore:  at 9.4 gpm w/ your pipe, and 100 ft from source, you will have ~50 psi.

So:    Average watts = 9.4 gpm x 50 x 2.3 / 10 = 108 watts.

Not a lot of power....

[Tugger]

Thanks for the info...
108watts...hmm...not much at all..

108 watts x 24 hours = 2.592 kwh per day..
2.592 X 30 days = 77.76 kwh per month...
77.76 kwh x 12 months = 0. 93312 mwh per year...

Somehow i went from not much to just about a megawatt...did i do the math wrong??

Cheers
Tugger

[mike90045]

It builds up because it's on 24/7  Great for battery charging for inverter based systems.

[AdeV73]

did i do the math wrong??

No, but I think you overestimate the size of a megawatt-hour: Over the course of the year you'd generate 0.946MWh (assuming a 365x24 year). If you switch on your 1KW electric bar heater, you'll have used all of that electricity in 40 days, leaving you some 315days to shiver....

A megawatt really isn't that much electricity, unless it all arrives in a short space of time