Small Waterfall energy capture

[Novelist]

I am planning a small waterfall inside my new greenhouse project. The water will be gathered and treated in a tank ten feet about ground level. The water will originate from run-off water that I capture, but once inside it will be pumped up from the lowest of my two pools. The entire system will be about 6,000 gallons in total.

Part of the use of the pond/waterfall is for solar mass. It will help keep the temperature moderated day and night. It is also for esthetic purposes and I want to light it and use a couple of fountains. I thought that I could use the energy of the small waterfall to power to lights and fountains for the water system. I know I won't get a lot of energy, but every little bit is good, otherwise I'm wasting it.

So, I am looking for advice on a tiny hydro generator I can either build, or get locally. No expensive hydro-systems, the energy recovery isn't worth it.

Anyone got advice for a newbie?

[wdyasq]

Doing some rough math, I get 6000gal x 8.3lb/gal x 10' = 498000ft/lb energy

498k/33k/minute = ~1/4 HP if you released all the water and caught it with your device. If you had a 20% efficient system you would get less than 40 watts energy for an hour.

Just some rough numbers.... not owrth it IMO.

Ron

[kurt]

let me get this strait you wanna use electricity to pump water way up high then let it fall through a turbine to produce electricity right??? you do know that it will take more electricity to pump the water up there than you will ever get back right?? there is no free lunch in this world the laws of physics always have to be paid.

[Novelist]

"I'm givin' her all I got, Cap'n; I can't break the laws of physics man."

My waterfall is primarily for heating, cooling, serenity purposes. I am creating a zone of beauty in my back yard. What I figured was that as long as the water was coming down and I had already accepted the costs of pumpping, filtering, etc, I might as well try and recover some of that energy to do minor tasks. I am thinking about a generator from a broken thingy of some kind that can be wired into small batteries and power some lights. Nothing that takes expense. It's more an experiment for a larger scale outside project later.

[jonas302]

a small dc motor will do it for you hard to say what will work maybe an amtec will make some power about $40 at surplus center or a smaller motor casette player or disk drive or vcr come to mind

No it isn't much power but maybe you can charge a few cells put leds in your waterfall isn't going to save you any money but adds a conversation starter

besides once you get that done a windmill will be next on your mind

[ruddycrazy]

Hiya Novelist,

As Kurt has said 'there aint no frre lunch' and you stated you've already allowed for the power used to pump the water upstream. Try and find an old decent biploar stepper motor and use that for your small generator. For accent lighting just use led's, put say a 12 volt 7ah sla battery or two there for power backup and with the little power you attain from the the small stepper genny you'll be surprised just how good the led light setup will look. If you need a hand on the circuit side I'm sure we could chime in and help you out.

Now if you go down the track of using a stepper motor checkout Gizmo's website on the mini wind genny using a stepper and there's your circuit

http://www.thebackshed.com/windmill/assemblyMini3.asp (thats the electricial page)

hope this gives an idea or different option

Cheers Bryan

[Novelist]

The company I work for uses small three-phase DC motors and we always have motors that are being thrown out as the medical devices pass through engineering. We can't reuse any of hte parts here at work, so we can take parts home at that point. I had an EE draw me up a schematic that would allow for the water to enter the motor and turn it and charge a battery. I am going ot rig up a test and see if that works to light some simple LEDs.

[powersource4U]

Don't let other discurage you from recovering engergy that you are already intending or going to use. Many Simple solutions always make a big impact to any project or organization when it comes to saving money.

[stasis]

It's unclear to me whether you want only lights (LEDs) or also want to see the little hydro whirring away in your waterfall.  If it's the first, i.e. lights only, why not just tap off the power that you use to run the pump , reduce the voltage, rectify it or whatever -  and away you go!