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[Clansgian AT wmconnect.com]

Rob writes:

> Could a ram pump pump water to above the workshop?
> I guess I should ask if there is any place above the workshop you could 
> store water <g>? Be a drag to have to build a tower to hold a water tank... 
> A 12' ft diameter swimming pool holds 'about' 1200 gallons. At around 8 lbs 
> a gallon that's a good bit of weight.
> 

This provides a good example for my 'do the math' saw.  The house and shop 
are on top of a ridge, there's no higher ground here.  But one side of the 
ridge 
near the shop is steep enough to get a 10' fall not far away from the shop.  
If the generator were there, the electrical lines would be short enough to 
ignore the line losses.

So if I have my 1200 gallons of water, I think the 12' pool filled to 36" 
holds about 1600 gallons, and I want to run, say, my table saw, how will I 
fare?

The saw requires a startup current of 14 amps and a continuous current of 
probably 7 amps.  Let' s say it needs the startup current for five seconds.

Hydroelectric generation using the type of equipment the homesteader could 
buy or make follows roughly this formula:

watts of electric power  = head in feet x flow in GPM x coefficient of .18 x 
30% efficiency[typical]

Let me round down the 14 amps at 110v to 1500 watts for arithmatic's sake.  
Ignoring any losses after generation due to line loss or inversion, how much 
of 
my 1600 gallons of water would I need to get the saw motor started?

1500 = 10 x F x .18 x .3
F =  2700 gallons for one minute

About 225 gallons for the 5 second sartup current

Using the same formula to calculate the needs for the 7 amps the saw needs to 
run after startup

750 (watts) = 10 ft head x flow rate x .18 x .3

F = 1400 gallons for one minute  --- roughly what I have left in the pool


So after using the ram pump to elevate the water the 75 feet to the pool 
(which is feasible at a very low rate of flow into the pool)  and after the 
pool 
has filled (which would take about four or five days, but even with a very 
unlikely flow rate of a gallon per minute it would fill only once a day) AND 
ignoring all losses after generation --- I would flip on the table saw and it 
would 
start up and run less than a minute before I had emptied the pool.  Of course 
in the real world the DC generated woudl charge batteries which would be 
inverted to AC, but all this only costs me more of my power through losses.  
That 
is, I flip the switch, get the piece fitted to the rip fence or mitre guide, 
line up the cut, get ready to saw and  .......zzzzzzzz ... out of power!

The thing that the enthusiastic RE'er and the world at large it seems fails 
to come to grips with is that if we are going off the grid and depend on our 
own ability to generate electricity, we are going to live with very much less 
electricity.  And if we are going to live with it off the grid, why not get 
used 
to living that way ON the grid.  And if we do, obtaining that amount of 
electricity is not much of a problem or expense.

James