Pumping water

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tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Wed Oct 26, 05 8:58 am Post subject:
That's the problem though, only when it's sunny(ish), with a ram pup I could have a gravity fed irrigation system that's constantly topped up

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Wed Oct 26, 05 4:18 pm Post subject:

A few points:
1/ How much flow do you have? I gather that a ram pump works on the concept of using most of the flow (say 90%) to lift the remainder (10%), and with perfect efficiency you'd be able to lift that 10% 9x further than the drop that the 90% is made to work through. So if you have a 4ft working head, and want to lift water 40ft, your irrigation flow is going to realistically be somewhat less than 10% of the spring flow.
2/ The spring flow is unlikely to be constant over 12 months. Your maximum irrigation demand is likely to coincide with minimum spring flow. Its called summer!
3/ However you capture the spring, you'd have to have the outflow in a pipe, to take it lower, in order to get a pressure head ("drop" in para 1) to drive the pump.
4/ A solar electric pump has the advantages of not 'stealing' any of your available water supply to drive it, and pumping more water at the very time of year when most water is needed for irrigation - summer, long hours of sun. And, yes, It would make more sense to irrigate in the evening, and yes, solar pumps don't work after dark, but I was thinking that you were mainly bothered about filling a big pond near the highest point of the property, rather than distributing it from there...

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Wed Oct 26, 05 4:23 pm Post subject:

dougal wrote:

I was thinking that you were mainly bothered about filling a big pond near the highest point of the property, rather than distributing it from there...

Nope, to fill a tank of some type at the highest point to run a gravity fed irrigation system. You're right though I'd have next to no use for the water from October->March unless it's pure enough to bottle...

How do I work out a flow rate? Bear in mind that the property isn't mine (yet) although I'll probably be nipping over there on saturday.

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Wed Oct 26, 05 4:33 pm Post subject:
I could have a spring fed pond for use as the reservoir for a gravity fed system but about 1/3 of the land is uphill from it.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Wed Oct 26, 05 4:58 pm Post subject:

tahir wrote:

dougal wrote:

I was thinking that you were mainly bothered about filling a big pond near the highest point of the property

Nope, to fill a tank of some type at the highest point to run a gravity fed irrigation system.

Errr, isn't that what I said?

Quote:

How do I work out a flow rate? Bear in mind that the property isn't mine (yet) although I'll probably be nipping over there on saturday.

Its only a rough estimate of the resource.
Can you use something like a scaffold board with a notch as a temporary dam?
You need to judge how long it would take to fill, say, a 5 litre jerrycan.
You might compare it to the flow you get from your garden hose, and then measure that.
Its just to get some sort of feel for the flowrate.
As to how you find out the flowrate in August, well, I suppose thats down to intelligence gathering!
Mr Solar's pump at 2000 litres/hour would fill that 5 litre can in under 10 seconds...

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Wed Oct 26, 05 5:13 pm Post subject:

dougal wrote:

tahir wrote:

dougal wrote:

I was thinking that you were mainly bothered about filling a big pond near the highest point of the property

Nope, to fill a tank of some type at the highest point to run a gravity fed irrigation system.

Errr, isn't that what I said?

Oh yeah

So are you saying I should look at using a solar pump to get the water up there? I reckon it's probably 300 mtrs up a gentle slope, I reckon the flow rate is huge in comparison to a garden hose, maybe 20 or 30 garden hoses?

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Wed Oct 26, 05 5:20 pm Post subject:
And the flow looked pretty good in August too

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Wed Oct 26, 05 5:59 pm Post subject:

tahir wrote:

... I reckon the flow rate is huge in comparison to a garden hose, maybe 20 or 30 garden hoses?

That sounds like you have plenty flow to get '1 garden hose worth' of flow up the hill 24/365 with a ram pump...
Now then, about this bottling plant...

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Wed Oct 26, 05 6:01 pm Post subject:

dougal wrote:

That sounds like you have plenty flow to get '1 garden hose worth' of flow up the hill 24/365 with a ram pump...

But would I still be better considering a solar? I'm seriously thinking about getting the water tested for potability

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Wed Oct 26, 05 6:24 pm Post subject:

tahir wrote:

dougal wrote:

That sounds like you have plenty flow to get '1 garden hose worth' of flow up the hill 24/365 with a ram pump...

But would I still be better considering a solar?

I'd expect the hydraulic ram to be much cheaper than solar panels and electric pump.
I don't know why Mr Solar suggests that you would need multiple pumpsets (and panels), which would get very expensive. It should be possible to get an electric pump to deliver the required output pressure. I'm gonna guess that it can't be too difficult to control the starting of that pump (you don't want it stalled...)

It can be difficult to judge a flow when its oozing across a field, which is why I suggested the temporary dam. But this sounds like a significant flow...

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Wed Oct 26, 05 6:28 pm Post subject:
I'll try and take a closer look but the source is covered by a huge (I mean humungous) concrete slab, we tried to move it last time we were there but it wouldn't budge.

Mr Solar

Joined: 23 Oct 2005
Posts: 10

Posted: Sun Oct 30, 05 3:49 pm Post subject:

I sugested using solar power direct with a DC pump of this type becouse as yet nobody has spoken about the cost of a Ram pump.
This 2,000 litre an hour pump when the sun shines on the 2 panels is 320.00 pounds, each PV panel of 55 watts is 200.00 pounds + some wiring and a pole + VAT
Its maximum head is 12 meters through a 1/2hose.
So pumping water with 110 watts DC @24-34 volts up a sloop of 300 meters is not going to work.
However there are more powerfull pumps needing a larger PV array that can do the job, all depends on which is the best cost for this situation, may well be a Ram pump

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Sun Oct 30, 05 4:36 pm Post subject:

Mr Solar wrote:

I sugested using solar power direct with a DC pump of this type ...

Is that all one needs to do? Hook the DC pump up to the output from the PV array?

I'd guess that we are talking about a centrifugal pump, which would turn without doing much pumping when the solar power was reduced, like early morning, late evening...
Because its turning (albeit ineffectually), I guess there shouldn't be any risk of damage from the (potentially high) current flowing while it was stalled.

My suspicion is that some sort of basic control circuitry might be needed with a high pressure (positive displacement?) pump, so that it was only switched on when there was enough power to drive it...

Mr Solar

Joined: 23 Oct 2005
Posts: 10

Posted: Mon Oct 31, 05 8:59 am Post subject:

This German made pump requires a higher voltage than 12 volts, hence connecting 2 x 55 watt PV panels together to create a closed circuit of 24 volts, open circuit of 36 volts.

The number of PV panels used is always down to need and budget.
Conect 10 x 100 PV panels together, same single pump, you still have the same voltage output.
This simple way to draw water from 6 meters down, pump 12 meters in height, placed anywhere in a feild for example to keep drinking troughs for cattle full up from a well.

Other uses, small scale irigation using a DC time clock to open and shut the circuit. In greece, the pump draws water out of a well, into a 1,000 litre ground mounted holding tank when ever the sun comes out through a ball cock, then a second ground mounted pressure pump of 240 volts AC takes this tank water and pumps it to the homes cold tank in the roof space some 100 meters away, also on a time clock using a wind/pv hybrid system for the home with a 3,000kw inverter via a battery bank.
They have no mains electricty.

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Mon Oct 31, 05 10:50 am Post subject:
HOw big are 10 x 100v panels going to be?

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