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[Clansgian AT wmconnect.com]

> 
> FWIW, I got the 1200 gallons as that's what I recalled the paperwork said 
> with the pool (way back when <shrug>).


Probably an 'at least' situation.  And some 12' pools aren't 36" tall.


> 
> Ok here's how I 'saw' it. A 2" pipe coming out the bottom of the tank 
> running down to the generator ( http://theepicenter.com/tow082099.html ). 
> The 2" is reduced to 1/2" and that stream is directed to the (100 amp?) 
> auto alternator, the hope is to get it up to 3600 rpm and produce the power 
> you need.

Yes, that's the hope, but what's the math?  That link is an excellent 
dissertation on alternators, but the article talks about connecting it to an 
IC 
engine.  To get an alternator up to 3600 rpm *under load* is quite a bit of 
torque. 
 I've been transplanting in the greenhouse all afternoon which is such a Zen 
meditation that numbers have been rendered meaningless for the moment.  But:

The reduction in pipe size will greatly increase your pressure but reduce 
your flow rate, no pun intended, but of course it's a wash (except for 
accommodating the size of your turbine blades or wheel).  The amount of 
current you and 
generate (wattage actually, but current since from the alternator the voltage 
will be fixed) will depend on head space and flow rate.  As with my previous 
pontification, the wattage will be determined by:

power = head x flow rate x .18 x efficiency of the generator

100 amps at 12 volts is 1200 watts

How fast is that water going to come out of that 1/2" pipe??  Let's suppose 
for a minute it is a gallon a second.  And let's suppose you have a typical 
generator that can convert the mechanical energy into electrical energy with 
an 
efficiency of 30%.  The head needed to generate 1200 watts with a flow rate 
of 
60 gallons/minute would be 370 feet.

I made up the 60 gpm, of course.  If you really rigged up a 2" pipe of a 
certain head and reduced it to 1/2", the flow rate is some fixed value that 
could 
be calculated, but geeeze, a gallon a second out of a 1/2" pipe would be a 
hell of a thing.



> This is all off the top of my head ... I'm guessing the ten feet high for 
> the tank is not going to be enough. You could always just build the 
> generator.
> 

I'm keeping those plans, but right now electricity is cheap and gas is not.


James