[spiritoflennon]

Hi,
I was hoping that someone may be able to help me with a little technical question I have. I was reading a permaculture manual last night, a section on hydraulic rams. Now previous to this I was looking to buy a property with a river in order to build a mini hydro generator for electricity needs. The write up claimed that a head of as little as 0.5 M ( 1 1/2 feet ) could be used to generate a good head on the Ram, now I'm not 100% sure what constitues a head. So my question was this. Would it be possible to place the inlet for a hydraulic pump under any source of water ( for example a pond ) and expect the pressure from the water above the inlet to fill the ram and generate a head which could then be used to power a generator?

[Frank]

Head typically refers to the height of water available to generate electricity. Water needs to change elevation in order to perform work. You also need to consider flow rate i.e. 20 gpm at 10' of head is theoretically the same as 10 gpm at 20' head. I *think* a rule-of-thumb is that head X flow divided by 10 gives watts available ex. 20 gpm * 10'/10 = 20 watts electricity.

Placing an inlet to some generating device under a pond surface won't work unless you have an outlet some distance lower to locate a turbine/generator. You're simply using gravity to perform work.

[spiritoflennon]

I'll go back to looking for a site with a river then. However...

"Placing an inlet to some generating device under a pond surface won't work unless you have an outlet some distance lower to locate a turbine/generator"

Hmmm..

[pip]

For pump calcs the following equation gives power required. I assume it will work for getting power from flowing fluid as well.

HP = (gpm x head in feet x specific gravity)/(3960 x efficiency)

1 Horsepower = 745.7 watts
specific gravity of water = 1.0

[Frank]

"Placing an inlet to some generating device under a pond surface won't work unless you have an outlet some distance lower to locate a turbine/generator"

Hmmm..

don't forget, unless you have an ongoing source of water into the pond, all you'll do is empty it!

[spiritoflennon]

Maybe I could set up a circle of ponds, with each pond being lower than the previous but higher than the next.

[tmazanec1]

A little off topic, but I just could not resist
An early language translating program was tested with a randomly chosen encyclopedia article. The topic was "hydraulic rams". The text came out apparently in the target language. The reporter covering the event then suggested translating it back. The article came out titled "Water Goats" (and you can imagine how the rest of it read!)