Help estimating the amount of water from a solar powered well

azrc

Hi, other than minor help with my neighbor's generator powered well, I have no experience with pumps or water...

I'd like to know if anyone can give me any real world experience with what types of flowrates with a solar pumping station. Right now, my neighbor can get about 12 gal/min from ~320' well and a 1.5HP or 2HP. They are not sure about the pump size or the depth, but that number is in line with what others have told me in the area.

I've looked at the 2SQF-11, but depending on which chart I look at this may or may not be suitable. The other possibilities are 6SQF-2 and 3SQF-3. I can go up to ~2KW of panels. The area gets about 6.8hours/sun/day

My other pumping problem is for another well at 140'. Thinking something like 16SQF-10 or 25SQF-7 at similar conditions (~6-7hrs/day).

I would like to get the maximum amount of water per day through each system (for irrigation).

Thanks for any information.


edit: These are 100% off grid with no chance of grid becoming available and also I'd like to do this without generators as that is not a viable option either.

BB.

Re: Help estimating the amount of water from a solar powered well

I would be starting with the pump curves too... Perhaps you are at the point where you need to talk with a supplier or two of the pump systems themselves.

NAWS (Northern Arizona Wind & Sun--Our host) I am sure has lots of experience with wells... And perhaps a local well guy in your area that has work with solar powered pumps would be a help too...

Do you have any idea of how much sand is in the well--that can affect your pump selection too.

-Bill

azrc

Re: Help estimating the amount of water from a solar powered well

BB. wrote: »

Do you have any idea of how much sand is in the well--that can affect your pump selection too.
-Bill

Thanks, no idea about the sand. I have never seen any in the water that comes out of the well, if that makes a difference.

I'm sure I'll be talking to people and asking a lot of technical questions when I get close, I was just curious as to how well real world experience matches up with the curves and also why 2SQF11 curves are different on different charts that I've read...whether the power requirement is too much for the given graph or whether the pump can't handle that depth.

Thanks again. I may give NAWS a call this afternoon.

mike95490

Re: Help estimating the amount of water from a solar powered well

Do you want pumping daylight hours only, and a minimum battery bank, or do you want larger batteries, larger solar and more hours. Depending on location and sun hours, limits your pumping. From my experience, 1/2 hp needs 1,000w running.
i'd feed it with a 1700W array, to be sure it's pumping from the sun and not batteries. Set a timer to control the run time to sun hours, 10am - 2pm

Can you stand a cloudy day, no pumping? Rainy day ?

BB.

Re: Help estimating the amount of water from a solar powered well

The pumps actually change speed according to the amount of solar power available (cloudy day, the pump runs slower and pumps less water--but it still does pump).

Also, the deeper you go, the slower the pump will turn (to not exceed motor / solar panel ratings).

-Bill

mike95490

Re: Help estimating the amount of water from a solar powered well

Those curves are tough to read and I found MANY vendors who just pick something they have and say it will work. May be true on grid, but for off grid, you have small margins.
Also consider the price difference for DC pump and it's controller, vs Solar PV, charger, batterys, inverter and standard pump & standard controller, or 3 phase pump and VFD controller.

azrc

Re: Help estimating the amount of water from a solar powered well

mike90045 wrote: »

Do you want pumping daylight hours only, and a minimum battery bank, or do you want larger batteries, larger solar and more hours. Depending on location and sun hours, limits your pumping. From my experience, 1/2 hp needs 1,000w running.
i'd feed it with a 1700W array, to be sure it's pumping from the sun and not batteries. Set a timer to control the run time to sun hours, 10am - 2pm

Can you stand a cloudy day, no pumping? Rainy day ?

Yes, daylight only. I guess it's OK if it doesn't pump at all on a rainy day. This isn't anything commercial, I just want to get a feel for what type of garden I can have and how many trees I can plant.

mike95490

Re: Help estimating the amount of water from a solar powered well

I just want to get a feel for what type of garden I can have and how many trees I can plant.

That boils down to how much $ you have.

I'm pumping daily, into storage tanks, about 1,500 gallons to water a 3/4 acre hazel orchard. Because of vendors, and local supplies, I went with conventional well pump, and off grid system to power it, shop, and my future house.

azrc

Re: Help estimating the amount of water from a solar powered well

mike90045 wrote: »

That boils down to how much $ you have.

...as it always does.

Main thing is if graph shows x gallons pumped/day using y solar power at z hours per day of availability, how close is that to accurate? How much padding and ideal assumptions are made and how far from realism are ideal situations, a few %, 80%, 2x. 10x...?

Oh, the water is not 96 degrees and the outside temperature is not -18F and it's a perfectly sunny day in August? That's different.

mike95490

Re: Help estimating the amount of water from a solar powered well

Pipe size and length. Big factors, I'm pumping 9gpm, and use a 2" pipe for a 900' run, 65' elevation. If I go smaller pipe, the flow resistance goes up and I need a larger pump !!