low volume, very shallow well, solar pump needed?

SystemSystem Posts: 2,511 admin
This question is similar to donrmurray's question on March 18....but hopefully an easier solution.
I have an old hand-dug well (no casing) about 3 ft. in diameter. The water level is only 10 ft below the the ground surface right now. The depth of the water is unknown but I am guessing only about 3 ft deep (after I clean it out).

I would like to simply pump the water out of the well (very slowly) to a water trough for a few cattle about 20 ft from the well opening. Will a surface pump work here or will I have to get a more expensive submersible? I will need it to pump very slowly to give time for the well to keep up (not much water down there I don't think, at least not this time of year). I would be happy with only 100-125 gallons per day (1/4 gpm) if the well can keep up. Possibly bad news: Elev is about 7200 ft.

Is there an entire kit I could buy so I don't have to worry about interoperability issues? I would be willing to spend around $400 if necessary.

One other thing... the well is on somewhat of a slope and the water trough would be below the top of the well but not below the water level...if this matters?

Any help on this matter would greatly appreciated.

Brian
Winston, NM

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: low volume, very shallow well, solar pump needed?

    it sounds like you might want a dc fountain pump with a small solar panel and booster regulator on it. be aware that during cloudy conditions it won't pump optimally and of course it won't do anything at all at night. also know that if the pump starts sucking air in the case of a dry period or pumping it faster than it gets replenished that this could destroy the pump. float switches do great at preventing such an occurance, but is the cost of it worth it on a cheap pump?
    what size pv depends on the pump's requirements so research the pump first and then you could match a pv to it.
  • System2System2 Posts: 6,290 admin
    Re: low volume, very shallow well, solar pump needed?

    Too bad you didn't have some way of determining just how much water your well can produce per 24 hour period. From your description of the well, I suspect that unless there is a good spring in the bottom of the well, it may not be able to provide that amount of flow for very long. Once the surrounding soil gets drained, the well could go dry, unless you get lots of rain.
    I live on a well and am very lucky to have a spring in the bottom. My mothers well on the other hand, has no spring, so during drier times, she must be very careful not to "run the well dry".
    Any way you could borrow a gas pump and drain the well a few times to see how long it takes to refill?
    Just a thought before you spend a bunch of money.
    Best of luck
    Wayne
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: low volume, very shallow well, solar pump needed?

    you know wayne i just dug under the back of my cellar floor and hit water 6 inches down. i did know it was there from laying footers for some posts in my basement before. i have a spring that runs under my home which sits on bedrock so there is little space for it to go anywhere else. it made its way into my sewer and did some major damage to my sewer and my 6ft front retaining wall i just put in 15yrs ago. yes the 1st one was destroyed by that flow as well, but the spring is picking up momentum as the plumber estimated my flow after a week long soaking rain at 3.5 gallons per minute. i saw it about .5 gallons per minute when we recently just had 12 straight days of no rain. i'm thinking of possibly using this geothermally. the simplist way would be to pipe it up into the house with copper pipe to collect the summer heat that builds in the house. a heat pump would be better, but i don't have one and don't see me getting one soon. at present i am pumping it out of the hole with a 1/3hp flotec from home depot(120vac at 9amps). i need to enlarge the hole, er well, abit more, but it works ok as it is. it turns on and empties a few gallons of water in a few seconds through 1.25 inch hose. think that would have enough push to go vertically about 30ft! :-D i'll have to give this more thought as to a good design.
  • System2System2 Posts: 6,290 admin
    Re: low volume, very shallow well, solar pump needed?

    WOW! That gives one many great possibilities !

    My uncle used a spring to feed cold water through a car radiator with a fan blowing air through it and had himself a great little "air conditioner" that used very little power. (just the fan)
    Wayne
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: low volume, very shallow well, solar pump needed?

    i will need power to send it vertically with a pump and a fan to blow cool air around as well. if i mess up on the plumbing of this my other half would kill me after i clean it up. :evil:
  • System2System2 Posts: 6,290 admin
    Re: low volume, very shallow well, solar pump needed?

    Thank you both for your help.
    I believe there is a spring in the bottom or at least something that keeps the water level where it is. May and June are our driest months in NM and so I figure this should be as low as the well ever is. But you're right, I think that I will just pump it out a couple of times w/ a gas pump and generator and see if/how long it takes to refill before investing in PVs, batteries, pumps etc.
    Do you have any recommendations as to specifically which pump and PV? And can will it pump directly from the PV or will I have to go through a battery? Sorry, I'm really ignorant when it comes to this stuff...
    Thanks again.
  • BB.BB. Super Moderators, Administrators Posts: 31,038 admin
    Re: low volume, very shallow well, solar pump needed?

    The short answer is no, you do not need (or probably want) batteries for this use.

    The simplest would be to select the appropriate pump, then a couple solar panels + mounts. Then wire them together. It will pump when there is sufficient sun.

    Next, you may want a couple switches. One for when the tank is full, another for the well to prevent the pump for running dry. Remember to select the correct type of switches (DC, right current and voltage). Selecting the wrong ones will probably cause them to fail within a few weeks or months (DC current is much more difficult to switch than AC--so check the ratings).

    Next, you may wish to install a "linear current booster" between the solar panels and the pump... Basically, the reason is that a solar panel works best (most power) if the solar panel is running near rated voltage (Vmpp--maximum power point voltage) and if the sun is not full-on to the panel (morning/evening) the current is reduced. Motors, typically can run on less voltage, but need heavy current to start and run--and will pump water--just not a full speed. The current booster is an electronic converter that converts the high(er) voltage-low current to a high(er) current-low voltage for the pump motor (kind of like a "DC" transformer). It is not needed, but, from what I have read, can significantly increase the amount of water pumped in a day.

    There are other small things to watch out for too... One is that you want to make sure the water does not overflow and cause damage if the switch(es) fail. Second, don't oversize the pipe--you want to keep the water moving (when pumping) to prevent settlement/clogs in the line.

    Wind-Sun (forum host) does have some water pumping supplies/equipment:

    http://store.solar-electric.com/sodcwapu.html

    Here is a few links that I have posted earlier to just give an idea about what is needed:

    Here is a rough graphic you can use to estimate the wattage of solar panels you would require (pump head vs gallons per day):

    http://www.solar-electric.com/PDF_files/L-SQ-SL-010.pdf

    Also Wind-Sun has a typical quote for a pump system--you can probably identify the major components that you would need from it:

    http://lib.store.yahoo.net/lib/wind-sun/Grundfos-325.pdf

    You probably should be working with your local supplier (or two for quoting) to identify the supplies needed and any misc. parts that may be still needed that they don't supply.

    This will answer some more of your questions too:

    http://www.solar-electric.com/PDF_files/L-SP-TL-014.pdf
    ----
    Once you identify the pump type/model/support equipment you are interested in (DC and works with solar), it is pretty much just picking the voltage/number of solar panels you want and the frame to mount them.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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