# Small Hydro idea



## bobp (Mar 4, 2014)

Does anyone here have experience to using a 'Ram Pump' to fill a reservoir/tank etc, or simple column of pipe or pipes, then using a gravity fed water jet, by dropping from a 4" or larger down to a 1/4" jet to drive a small turbine to turn an alternator?


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## jwal10 (Jun 5, 2010)

I have a microhydro generator run off a 2" PVC pipe, gravity fed from my spring through 2 small jets....James

http://www.rpc.com.au/pdf/HYD-062-Manual.pdf


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## Harry Chickpea (Dec 19, 2008)

Basic concepts:
Every change of type of energy creates losses
Pipe resistance creates losses
With liquid in a pipe, you increase speed at the expense of pressure, increase pressure at the expense of speed.
There is no free lunch

The maximum amount of energy in such a system would be if you took the energy at the site of the ram pump alone, placing a water wheel or turbine there. Everything else is a waste of energy and money.

You CAN do pumped storage, but the losses are horrific.


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## bobp (Mar 4, 2014)

I understand the issue of losses for various reasons, but there are no real losses with a ram pump that I can think of. You had nothing before, and the ram operates for free once installed. You can even have a second ram capture the waste water from the turbine I'm thinking?

The question would be what available flow would it take to justify the work and instillation expense


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## TnAndy (Sep 15, 2005)

Do you plan continuous production ? You'll need a lot of flow. 

The principal behind a ram is that you have a pretty fair amount of head to start with (that is what gives you the energy to drive the ram), and you need to lift a small amount of water on a continuous basis up to a higher elevation. That is usually a storage tank for domestic water supply....which is taken off periodically as water is used.

IF you have enough head to lift enough water to drop it back down into a turbine, you should look at simply dropping it into the turbine to start with.

IF you plan to generate only when you get enough storage to give you decent flow and head from your storage tank, you have the issue of stopping and starting that flow, in addition to the length of time you'd generate....probably a short time.

I'm not gonna work out the engineering behind it, as for one, you've given no numbers to work with....but my 'seat of the pants' guesstimate is exactly what Harry said.....the energy losses will be so horrific, it won't work. 

I did work the numbers on an overshot water wheel once for a buddy, and he had 100gal/min dropping 20' vertical over 1000' horizontal.....and it only worked out to around 1/2hp.....350w. Even though you'd get 350w x 24hrs/day, the economics of setting it up just didn't justify the return. (and that was assuming we completely bypassed permitting, which may or may not have been possible.)


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## Harry Chickpea (Dec 19, 2008)

Yeah, running the math is a real eye opener for beginners having visions of endless energy from a small stream. IIRC, my stream would do about 200 watts. I might fiddle around with something at some point, but not for serious power.

A couple of related articles from a website that I found fascinating:

http://www.lowtechmagazine.com/2013/08/direct-hydropower.html

http://www.lowtechmagazine.com/2013/01/mechanical-transmission-of-power-stangenkunst.html


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## wy_white_wolf (Oct 14, 2004)

Why add the complexity to the system. Just put a microhydro designed for the lower head where the rampump would be. Keep It Simple S*****

WWW


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