How can I increase the water pressure in a low head hydroelectric system?

[jcterzin]

Hi Everyone. I'm new here and glad to find a community with ideas and creativity.

I have a stream behind my house that I feel could be utilized for hydro electrical power. I am no engineer but I've been reading up on it's potential for electrical energy. Trouble is that this stream has very little head in my area (only like 3 - 5 ft.) for me to utilize in order to get the kinetic energy i need to move a turbine (I've been looking into impulse systems) So... I've been looking up ways to fix that. I saw that a Ram pump could lift water to create artificial head but I don't know if I could lift enough water to get a solid jet of water to turn a turbine. Anyone have any suggestions on where I should start to either create enough force, or should I go in a different direction? The river flows at probably 60 - 80 gallons a minute.

 

[DickL]

Based on some numbers I've run, it does not look as though you have enough flow (and head) to make it a very useful project.

I estimated the potential (ideal) power at approximately 0.07 Hp or 0.05 kWh. Here is how I made this estimate:
Power = mass flow * head
The mass flow is the 60 - 80 gal/min, converting to lbs/sec it is 60 gal/min * 8 lbs/gal = 8 lbs/sec
The head = 5 ft.
Power = 8 lbs/sec * 5 ft = 40 lbs-ft/sec
or in HP = 40 lbs-ft/sec / (550 lbs-ft/sec/HP) = 0.07 HP
or in kWh = 0.07 HP * 0.746 kWh/HP = 0.05 kWh
That is about 1- 60W light bulb's worth of power, and that is before any losses are subtracted.

What may be useful, if you have an emergency or night time use of a small amount of power, would be using the hydro power to charge a battery bank that would supply the emergency or intermittent power.

You may also want to double check that flow rate. 60 - 80 gal/min sounds pretty low for even a small stream.

 

[jcterzin]

DickL-

Thank you for the reply. You are right about the flow, it is probably more than that but even so It doesn't sound as if I can just throw a turbine in the stream and make enough power to operate my house.

I made a prototype turbine with 6 flat paddles and sat it in the water and timed the RPMs a few days ago. This thing was very primitive (we are talking paddles made of license plates and an axle of pvc all stuffed into a pickle bucket with the bottom removed.) It was getting 75 RPM. I put my garden hose to it and got the RPMs much higher, like 400 - 500. Wish I could figure out a way to create more water pressure like that out of my garden hose using just the water flowing and not much head distance...