Anyone experience to pump water with windmill ? 2

[sparky1976]

Guys,
Is there anyone had experience pumping water with windmill as power source.
I need someone to advise me a website or books about pumping water with windmill.
It is not a big one, I just need to pump water with suction head 25 meters pumps to a 3000 liters tank, for home use.

Thanks in advance
Pitat

 

[insideman]

When I was young every farm in America had one or more windmills pumping water from wells. These were very simple devices, easily maintained by home mechanics. However, they would not handle a suction head of 25 meters.
neither will any other device. You will need to find a way around that limitation.

 

[sparky1976]

Insideman,
How high the simple windmill water pump can handle suction head ? (Roughly)

 

[insideman]

Probably nine meters.

Pat

 

[TBP]

yamin - If you can locate an old set of the Audels "Plumbers And Steam Fitters Guide", they have this specific information. The set I have is from 1946 (copyright 1925), and windmill pumps & generators are covered in volume 3.

I don't think these books have been published since the '50s, so you'll likely need to find an old-timer who's got them in a box in the attic, or at a used bookstore or antique shop.

You may have better luck overall in finding current info on wind powered generators to drive a readily available electric motor driven pump.

Good luck with your project. I'd be interested in hearing how you make out.

 

[SteveKW]

I have purchased old books like that from Ebay!

 

[tstead]

A suction head of 25 meters means that the suction pressure is basically 190 psig and there are many pumps that can handle this pressure.

I don't think that is what you mean though so you need to be a little more precise on your suction conditions.


Tim

 

[Hush]

Sounds like a very shallow pumpjack arrangement, substituting the windmill for the pumpjack. 3 joints of tubing, 3 sucker rods, a pump seat nipple, and a ball pump. You shoud be able to get it all cheap or free as used oilfield surplus.

 

[electricpete]

tstead - I agree this terminology is confusing. I'm assuming they mean there is water at atmospheric pressure which is located 25m below the pump suction. Is that correct?

BTW - I think 25m of water column is closer to 35psi than 195psi

 

[sparky1976]

I mean, I will put the windmill and pump on a small hill and suck the water from hill valley that I measure 25 mtrs vertically.

 

[tstead]

O.K., that makes a little more sense when reading your posts now.

You can't do it - it is impossible for a pump to lift water more than about 39 feet or so (depending on atmosphereic conditions at the site).

Imagine you had a really tall tube - any diameter will do. You have the open end of the tube sitting in a large body of water. Now, you start to suck out all the air at the other end of the tube until you reach a perfect vacuum up there (perfect vacuums cannot be attained, but let's assume it can for our experiment.) Now, if you keep sucking the other end with your super shop vac, you get nothing because there is nothing to suck (assume there is still air between the water surface and the shop vac).

Since you are not removing anything, there is no room for the water to "expand" to and hence, the water level will no longer rise. So, what is that level? At one end of the tube, you have 0 psia, at the other end you have 17 psia. The water at the bottom is therefore "pushing" at a force equal to (17-0) psia - or just 17 psia. Since the water in the tube is static, it too must be pushing back on that water in the reservoir at 17 psia. Therefore, the water must be about 39 feet high.

Translated differently, the maximum theoretical height a pump can lift water is about 39 feet (adjusted for atmosphereic pressure, of course.) If you want to move that water up that 25m (82 feet) hill, you need a pump at the bottom to move it up the hill.

Of course, there is a nifty pump called a jet pump that operates on a slightly different principle - but those are only really used for wells. The pump basically sends water DOWN in the well where there is a jet/venturi that basically sucks water from the well where it is then sent back up the well and to the delivery source. Jet pumps are therefore inefficient by nature and probably aren't well suited (no pun intended) for use on a windmill where, let's face it, the amount of power generated and reliability leaves much to be desired.

Regards,
Tim Steadham, P.E.

 

[TD2K]

Tim, I don't disagree with your post's content but why use 17 psia? Atmospheric pressure is typically 14.7 psia and the maximum 'lift' on a column of water is about 34 feet. I've got to be missing something in your post.

 

[sparky1976]

tstead,
So you says that I cant do it if I put the pump up on the hill, how about I put the pump lower and the pump will have less suction head but more discharge head ?

probably for Mech eng this is a silly question, but I'm just electrical guy.

thanks

 

[TD2K]

Pumping it UP the hill isn't a problem, you just are limited on how much suction 'lift' you can have on the pump. I'd put it at the bottom of the hill assuming you will still get the wind there.

 

[tstead]

Brain fart there. I was working on a project at the time that I wrote that post and the suction pressure I was dealing with was 16.7 psig.....since normal atm is 14.7 I had a lapse of brainpower at that second

Tim

 

[tstead]

TD2K is right...it's not a question of getting it somewhere once it leaves the pump, its a question of getting the water to the pump to begin with. If you cant get the water to the pump then the pump can't get the water out of the pump.

It should be noted that no pump in existence has a suction lift of 34 feet because, let's face it, a perfect vacuum is impossible even under laboratory conditions let alone using a pump hooked up to industrial pipe. I don't care if you are even using a self-priming pump - unless you use a jet pump you are limited to a practical lift of around 20-22 feet. I have NEVER seen ANY pump that could lift water any higher than 22 feet (I'm not saying they don't exist, but if they do they are would be so esoteric that they would probably be precluded from: 1. being hooked up to a windmill, and 2. Delivering any real amount of water for any real-world use.)

Of course, as TD2K said, if you put the pump lower you might not get the wind you need. This is but one of the many shortcomings that windmills have - yet people still swear by them and say they can solve all our energy problems. Sorry I had to interject a little politics in this but I had to

Tim S.

 

[Hush]

Its been a few years since school and even then I sucked (no pun intended) at fluid mechanics so this is probably an irrelevant question but: How do trees do it? Your flow rate would be abysmal but could it be done with capillary action?

 

[ravisankar]

Hush,
The driving power for trees sucking water through roots is called osmotic pressure. When water is continuously being evaporated through leaves a pressure differential occurs. And as the salt concentration in the leaf cells is more, by law of nature, this should be diluted. Water from outside due to high pressure rises through the capillaries and passes through membranes into the cells. The pressure difference should be sufficient to pass water through these porous membranes. The quantity of capillaries are quiet high when compared to required flow rate (although marginal)

 

[Jeanbl]

One other solution....
Around here (Texas), windmill driven pumps as well as electric driven pumps getting water from water wells have one thing in common. The suction pipe (regardless of the depth) has a foot valve (check valve) at the bottom end of the pipe. Before starting the pump, fill the suction pipe with water. This way the suction head becomes minimal.
Once in a blue moon the valve gets some junk in there and it leaks. Using the pumps a while ussualy fixes the problem. Haven't touched it in 20 years.
Hope this helps.

Jean

 

[MortenA]

Priming a pump can be usefull but it dosnt solve the overall NPSH problem: You cant lift water more than approx. 10 meters by drawing because then it starts to boil. Usually the pump mechanism (not nessesarely the motor) will then be install down in the well.

Best Regards

Morten