windmill water pump + water storage tank + micro hydro ?

[farrago]

Could a raised water tower be used like a battery (to store power via potential energy from the elevated water inside)?

What if you took a mechanical windmill water pump (no electric needed) like this one...

http://www.aermotorwindmill.com/

..but you pumped the water into a small water tower

...like this one...

http://www1.istockphoto.com/file_thumbview_approve/1336222/2/istockphoto_1336222_windmill_and_water_



tower_in_front_of_a_red_barn.jpg

Then you ran a pipe out of the water tower and down into a micro hydro generator.  The run-off from the hydro-generator water goes back into the well or pond or wherever the water was pumped from.

The advantage (over strait wind energy) would be that you would have stored power for when the wind wasn't blowing.  You also create your vertical drop needed for hydro and flat areas like ours have almost NO natural vertical drop ..but we do have water and wind and mechanical windmill water pumps.

I am curious how long a full tank of water would last (if the wind pump wasn't running because of low wind).  I am also curious how much power such a system could generate.  I don't know much about electrical calculation ...so if someone smarter could calculate the feasibility ...that would be interesting to me.

-Tom

[fungus]

Just a quick thought ..

One metric ton of water:

Ep=mgh

Ep=1000*10*<height>

= 10kJ/meter height

One watthour is 3.6kJ  so there is approximately 3 watthours in a metric ton of water per meter of height, or one cubic meter (about 81 cubic feet).

To store the same amount of energy as two trojan 105 batteries at 12v, at 200AH (2400watthours) of stored energy, you would need for example 240 cubic meters at 10 meters height .. thats a lot, and you'd need a very strong structure to support 240 tonnes.

If I've made any mistakes someone please correct them

[fungus]

I did make a mistake ..'you would need for example 240 cubic meters at 10 meters height' , make that about 700 tons/cubic meters of water at 10 meters high.. Gravity is a very weak force.

[veewee77]

well, using stored water is a great idea, however, look at the cost of storing that much water opposed to batteries to store the same amount of energy. I am thinking space-wise, cost-wise, reliability-wise, sanity-wise. . . batteries win. . .

Batteries have some loss but the water would have SEVERE losses to do the same work.

Doug

[Norm]

   Here is a better way to test your idea.

   Get a small wind mill that will pump ....

maybe 5 gpm ....put a 55 gal barrel up on a sturdy platform.

   Now an automatic  syphon that almost completely

drains the tank thru a micro hydro generator,

when it gets too full.

 Another very small micro hydro generator is

constantly draining the tank from the bottom

   This is on a very small scale of course...

not intending to go off grid..

[thefinis]

If you are piping the water back down the well then one can recover more energy due to the increased drop but still it is not an efficient method. First there are the standard losses and then during times of higher winds much of the energy is just not captured. You get an increase in flow but lose the increased pressure potential. The mill is mostly free wheeling and trying to go into furl.

I think that a mini hydro unit might could be used with a windmill that had a packer unit with a pressure tank added inline. That is one of those units that does not use a stand pipe at the top but has a packer at the top so the water must flow out the exit pipe at whatever flow and pressure available. These were often used to make water go uphill from a windmill to a tank. This setup would allow you to capture both flow and pressure in high winds but to store energy would require a battery bank. Not a great way to go but should be better than trying to store pumped water and capture energy as it flows out. If needed for water usage you could also keep the water pumped above ground instead of piping it back down the well for increased power capture.

Truthfully it may be easier to build a new wind turbine than try and convert an existing windmill made to pump water.

Finis

[MattM]

Hydraulics are the only method of storage that is more efficient on a particular volume than a battery.  The downside is that hydraulics are costly, expensive, and extremely dangerous when there is a leak.  You'll be hard pressed to make it work economically.

On the other hand, I wonder if one could use hydraulics to level off high speed wind output.  It would be easy to build a series of small windmills that drive air compressors in series.  Under normal conditions the pressure and flow is regulated at close to a constant as possible.  (Perhaps heat from the sun could even boost line pressures when the wind is normally too light?)  Under extreme conditions the excess pressure could simply be vented off yet the generator still retains a constant flow through it.  Steam engines have used these principles for ages.

[spinningmagnets]

(Disclaimer: I haven't built anything yet)

I agree that if you're building this entire system for its electrical generating capability, it will be a lot of work and money for a tiny benefit.

In my situation, I am studying here for the purchase of a retirement property. My most desireable property will have significant elevation on half of it with steady water flow (hoping for 100+ feet, but I know its unlikely) I would like to build an upper pond and a lower pond with micro-hydro between them. I'd be happy with 12 volts, but again, I'm not holding my breath.

It's more likely I will be getting property in fairly flat land, and I am certain I will have an elevated water tank filled by a conventional wind-pump as in your picture, and next to a man-made pond. Major function will just be water storage with gravity flow to house and shop.

If there is more wind-pumping than needed to keep the elevated store topped off, it wouldn't be expensive to make a Turgo PMA to get a couple Watts of 12V. I've made a couple blades out of PVC on a particle board disc to attach onto a disc brake. If I ever get around to finishing it and testing it, the final version might be aluminum if it works OK.

"...Here, the streets are made out of a special material that we pay extra taxes for, it is called "pot holes"  -Deronmoped @ VisforVoltage.com

[zeusmorg]

 There are several utility companies that use a similar scheme for storing off hours generated electricity, long term costs are much lower than batteries, and efficiency is greater.

 Of course, they generally use a storage lake, and are located in regions that would easily support it.

 Calculating the capacity would depend on your hydroelectric setup figured in gallons per minute, and feet of head. There are many resources to figure all that.

 Overall, it is an interesting idea, but for most RE'ers I doubt it would be very cost effective over a battery setup, the controls and equipment would be cost prohibitive on a small scale.

 Let's say you put up a 1,000 gallon tank, (Huge I'd hate to see the support structure) and you installed a 5 gpm hydro generator on it, you'd have enough capacity to run for 3 1/3 hours. Now how long is it going to take to fill that tank?

 If you had the tank 50' elevated,at 5 gpm you'd get a WHOPPING 18 Watts or 13 kwh a month out of it. (That's assuming you can run it 24/7).

 Just running some numbers... 3,000.00 for a windmill and tower, probably 4,000.00 for a storage tank(assuming you can't build a pond for storage), add in piping let's say 500.00, then your hydroelectric generator, 2,500.00 So far you've invested over 10,000 or more.(adding in controls and inverters, etc).

 That amount would buy you a decently sized photovoltaic system. And the amount of power you'd have would be far greater.

 I'm not saying that it wouldn't be feasible in the right circumstances, just not with a water tank, the only way I could see if of benefit is if you had an area high enough to put in a storage pond that could give you a flow rate of at least 2 gpm, and a decent amount of head, and you built the majority of the components yourself.

 Remember you're using potential energy to pump the water uphill, then you're generating electricity off the downhill flow, so you've got losses. considering hydroelectric is about 90% efficient, and you also have the loss in pumping.

 Some ideas to improve on the scheme, pumping water uphill with a hydro ram, then storing it in a small pond. That would require a surface stream with a gpm flow of 80%  over what you wished to store. This is dependent on the height pumped.. Also it would make sense if you had a pre-existing pond that didn't maintain a steady outflow (and you had a separate source for extra water). Then you could upgrade it to hydro.

[freeEnergy4me]

I've recently thought about collecting water vs. city water. We get a lot of rain in my state, so if you built a giant collector barrell with all of your gutters pouring into the vat, you could have a lot of water flow to such a barrell.

The issue would be filtering water and having a diverting valve for city water.

But it seems the power system would be a whole lot simpler than a windmill even tho it probably generates less energy. You just need a fan of paddles connected to a generator and voila! Instant battery juics.

During a storm, we get a lot of down pours, with that directed from a roof to a funnel spout, it could generate some decent wattage, imho. Along with wind and solar, more juice for the battery pack.

[ghurd]

I don't think so.

Maybe work backwards from the formula.

Say 13WH.  1A for 1 hour.  How high is the gutter, or barrel (head)? How much water does it hold?  How fast will it be released (GPM).

How big is the roof?  Not square of shingle, but square feet under it.

How many inches of rain does it take to make 1AH?

I didn't do any math...

It takes A LOT!

I have been doing some rough work with small stuff.  Mostly aimed at streams, low head and AA nicds.

My house isn't big enough to catch enough water to charge AAs.

I'll probably end up useing $20 worth of solar.  Again.

G-

[34PatentAcres]

I've been considering the same type of thing (water storage to Demand power) I have a (old)cast concrete silo and thought of using a "green winmill" VAWT sails to pump water from a creek into the silo as a "battery" of sorts. However I also have a firetube wood boiler that I wanted to add to the equation using the silo pressure to replace the water converted to steam generated. (like a feed pump w/ back check valve)  The low pressure wet steam 180 psi (280deg F) would be nozzled to a hydrogenerator brass turgo. The spent steam would still be usable for low grade heat applications such as home or greenhouse heating. Any comments, condemnations?

[Drawbar]

I am not sure if it can be done on a small scale, but it can be done on a HUGE scale. Northfield Mountain has been doing what you are semi-suggesting for 30 years now.

You can read about it here. Pretty ingenious way to produce power for peak loads on the grid by using excess power at off peak times.

http://www.firstlightpower.com/generation/north.asp

[spinningmagnets]

http://www.fieldlines.com/story/2007/10/18/45127/063

a similar post

http://www.gazza.co.nz/waterpressure.html

water height/pressure calculator

Since the pressure at the bottom of a vertical pipe is based on the weight of the material above that is pushing down on it, fresh water weighs slightly less than salt water, and the weight of the atmosphere is slightly different from sea level up to Colorado (10,000 ft?), so...

This scuba depth calculator says its 19 PSI per every 10 ft of height, but your reading may be up to 10% less.

[befnme]

A possible alternative to this maybe (if you can use a stream or pond) to use a solar water pump and pump that water to the top of a micro water genny. As the water passes over the paddles it turns the genny thus creating dc power. After the water pases over the paddles it finds it's way back to the stream to be reused. Not sure of the amount of power that can be made. It seems so simple then. No water to try and contain or expensive materials to buy.

[zeusmorg]

  befnme, you'd be in negative #'s there. Why not just use the electricity from your solar panel! Double losses. First your loss pumping the water up, then the loss in the    micro-hydro genny.