Sun power water pump

[Tim Lamb]

A back of the mind project while you are all still in deck chair mode.....

How feasible would it be to construct a livestock watering system from

*off the shelf* components? A pond fountain won't do:-)

A standard water trough holds enough water for 2-3 days for a small bunch so permanent sunshine not too big an issue.

The problems are pump head/pressure. Inevitably the river is at the bottom of the hill so I might need something to overcome 10m static head plus flow losses and anything found at the control valve.

Also how to control the pump? Pressure cut off with a 30min timed re-start?

Do low flow reciprocating pumps exist?

For security, I had in mind putting the array on top of an 18' scaffold pole but how big is the collector likely to be? Wind damage?

Cost. This is agricultural!

[Nightjar]

Do you have any drop in river level across your land? If so, you might consider an hydraulic ram. They are ideal for giving a high head low flow output from a low head high flow source, without any external power required.

[Chris Hogg]

+1. You beat me to it!

and There's even a DIY option.

[Martin Brown]

Pity. A solar powered pond fountain pump on a car battery will do quite nicely for a greenhouse watering system.

Your best bet is a float switch and a couple of deep discharge batteries and swap as and when needed. Even the solar powered greenhouse pump couldn't keep up with thirsty plants on solar power.

It worked nicely on a 7Ah SLA though with the solar PV array just used to marginally extend battery life.

[Tim Lamb]

Fine for a clean stream over a hard bed but this is the Lea with a high silt burden, tidal flow from upstream sewage plant and numerous surface water drain discharges.

Fall over a gravelly stretch might give a local 3mph flow.

There are designs about for d-i-y versions but the bought in job is 'kin expensive.

[Brian-Gaff]

How does pole mounting it help? You really need a tracking system, but I don't know, so many things to consider. Why not make it battery powered and let the sun charge the batteries but if power is low due to lack of sun, you would need a back up charger from the mains. Brian

[Martin Brown]

A tracking system is just one more thing to go wrong.

You might want to make the tilt angle adjustable so that you can maximise solar gain and put a cheap mirror either side at 60 degree angle to roughly double the flux. Any more concentrated than that and you cook the panel leading to premature aging.

Last time I costed this sort of thing (for a greenhouse) a pair of decent SLAs and a charger won hands down. The solar powered pump worked really well when on a lead acid battery but was rubbish on its as designed solar panel (no wonder the original maker went bust!).

[newshound]

+1. My other thought, if it is windy, would be to charge the battery with a windmill connected to an old car alternator. More cost-effective than a solar panel, and genuine DIY!

At one time, wind powered mechanical pumps were not uncommon on UK farmland. ISTR that the fan (which had six or eight flat steel blades) was about 5 feet in diameter, and it was mounted on an angle iron pylon about 30 feet tall. A mechanical drive shaft came down to an underground pump.

[Chris Hogg]

This one's in Oz, but there used to be lots in Cornwall just like it. A crank on the shaft linked directly to a pump rod.

. Also

[Martin Brown]

Yes. The small wind turbines with about 1m diameter aren't at all bad if the thing is far enough away not to hear it whining gently.

Proper DIY too car alternator and a few bits of bent metal!

The simplest possible is a 45 gallon drum sawn in half back and assemble S shaped to back and held axis vertically in a frame.

[Nightjar]

One of the advantages of the hydraulic ram is that it doesn't need clean water. Large debris needs to be stopped from entering, but a simple inlet strainer will do that.

So you know which version to go for :-)

[Andy Burns]

Get one that's guaranteed *forever*

[Tim Lamb]

In message , Brian-Gaff writes

Pole mounting keeps it out of reach of local vandals. One possible site is 1/2 mile from the farmhouse and unsupervised apart from the fishermen.

Batteries could be part of the mix although electric fence batteries are regularly stolen here.

[Tim Lamb]

Is that 60deg. top/bottom rather than East/West?

Stock and water can be checked daily on foot. Lugging batteries requires a vehicle and access across potentially boggy ground.

I was hoping for something completely hands off.

>

[Tim Lamb]

Cue vandals lobbing rocks:-(

>

[Martin Brown]

Pointing due south with the elevation angle chosen to match the suns at transit. The configuration in ASCII art is \_/ where the bottom horizontal is the PV panel and the diagonals are mirrors.

The simplest optimised non focussing flux concentrator solution is a truncated parabola on either side with each having a focus at the opposite side of the PV array. You can get gains of around 10x this way but it really will cook the PV array even with active cooling.

It is optimal in the sense that any photon that enters the front aperture with perfect mirrors will eventually hit the sensor. Draw the ray diagrams to understand how it works for the simple hexagonal mirror configuration (which can be made very robust).

These things originally come from HEP and neutrino detection experiments but were known back in the 1970's oil crisis.

It is a bit dated now but this ancient 70's alternative energy book has some interesting stuff.

Major snag is it assumes a US latitude so some things don't work here. I can't recall if it has the concentrators though - I suspect they came later in a UK published "Solar Power" book.

I'd still recommend wind power as the preferred solution!

[Chris Hogg]

Green & Carter ram pumps were installed at Heligan Manor in 1880. After WW1, the gardens at Heligan Manor were left to become wild, as there were no longer the staff to maintain them. The ram pumps suffered a similar fate with the introduction of mains water, and were just left. The pump house and reservoirs in the valley below the house just silted up. About ten years ago, they were rediscovered, the mud all dug out, the pumps reconditioned by G&C, and they're now running again after being unused and buried in mud for 80 years or so.

Whether that qualifies for the claim 'forever', I don't know, but it's certainly a very long time, especially when you consider how long stuff lasts these days.

[dennis]

My solar thermal panels have such a reflector behind the tubes.

I have been contemplating making a big flat reflector out of mylar film (space blankets) and putting it at the base almost horizontal to increase the flux in winter.

[Dave Liquorice]

Go passive:

Not overly effcient with a 10 m lift, but I bet it can still deliver water faster than the stock can drink it.

Highly reliable, very low maintenance, simple in operation. Noise of the valve slamming shut every few tens of seconds might be a problem, box it in?

Just let it run 24/7 and the top tank overflow to somewhere that the stock won't turn into a quagmire.

Plastic I suspect it might not last too long but gives the idea from modern parts.

Or the Real Thing:

These are definately "agriculutral" seriously over engineered and with lifts up to 1000' rather more than I think you need. The price follows the quality over engineering so you probably won't like it.

[Dave Liquorice]

The ones I've seen have the fan attached to an axle with a crank in it. A solid link connects from there to the reciprocating pump at water level. As fan goes round, link goes up and down operating the pump, simples.

OK I guess the link is still a "drive shaft" but it's not a rotational one.