In Vol. II of his "Earthship" design series, Michael Reynolds describes
various system components for his home designs, including solar water
systems of a variety of types. If interested in various solutions, I
encourage you to look at the book (Solar Survival Press, ISBN
0-9626767-1-3). According to Reynolds, the problem with conventional
well pumps is that: (1) they pump water all the way from the pump to the
pressured water lines, which takes a lot of power; (2) they require
additional electricity when they first start up, which they do often
during the day as they cycle on and off to meet water demands. These
are the kinds of problems that James Ferrill is no doubt alluding to.
Rather than despair, however, you may want to consider Reynolds
One system he describes allegedly circumvents these problems by
replacing the single conventional large pump with 2 small solar-powered
DC pumps. The system is this:
1. Submersible solar-powered DC pump #1 at the bottom of the well,
pumping water up to a...
2. Cistern. The cistern can be above ground or buried.
3. Solar-powered DC pump #2 pumps water from the cistern into a
pressure tank, which supplies the house.
According to Reynolds, battery storage isn't necessary because the
cistern is filled during the day when the sun is shining. "The pump can
be very small because it doesn't have to produce waterline pressure from
deep in the well. It simply has to trickle water into the cistern all
day long. The water is then pumped from the cistern into a conventional
pressure tank which pressurizes the water lines for domestic use. This
pump is DC and also is much smaller and uses less electricity than the
conventional AC pump deep in the well. Therefore, this method reduces
the amount of electricity used every time water is needed as the two
small pumps use much less electricity than the one large pump." (p. 32)
Note that pump #2 is the only one that would draw off batteries (e.g.,
at night), assuming the cistern is filled during the day.
He describes other systems that are variants of this one. E.g.,
rainwater catch systems to supplement it, or cisterns up a hill from the
house so that gravity replaces the 2nd pump, etc.
Hope this helps,
> -----Original Message-----
> From: James Ferrill [mailto:jtferr@...]
> Sent: Monday, January 20, 2003 10:35 PM
> To: email@example.com
> Cc: noyesliv@...
> Subject: Re: [hreg] Updated bookmark file
> Mike's right about the small pond pumps. You can set up a simple PV
> directly running a small DC pump and it will work well. Those pumps
> small enough where nothing more than a panel is needed.
> Larger pumps are a different story. I once looked into what it would
> to solar power something like a hot tub or pool pump and the amount of
> power required is substantial. Plus, the systems are complex because
> have to have something that can handle the surge draw that a pump
> take. From everything I've read, even water pumping from a simple well
> been a challenge for many offgrid folks. Quite a few power the house
> PV system and will have a generator just to run the well pump and as
> backup supply.
> If you are connected to the grid, the best way to get the most energy
> use out of PV panels is to use a grid-intertie setup. You won't save
> money, but it will be greener energy, and you won't need batteries orhttp://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=solar+water+pumpi
> related support equipment.
> Google can provide tons of info:
> Also, panel prices are continuing to slowly come down. You can get an
> at this site: http://www.ecobusinesslinks.com/solar_panels.htmhttp://docs.yahoo.com/info/terms/
> Hope that helps.
> James Ferrill
> At 08:27 PM 1/14/2003, noyes livingston wrote:
> >thank you very much for the links
> >I am a school teacher ( math ) and since I live < 2
> >miles from where I work, I am thinking about buying an
> >electric bike to practice what I preach. I chose the
> >link about Currie technologies! Thanks
> >I have a paricular interest in two things
> >1) writing a grant to educate children (and adults)
> >on PV technology and other renewables so that I can
> >build a solar powered waterfall at our school and use
> >it as a piece of art that is pleasing to look at and
> >hear, as well as an educational demonstration. How do
> >I start and where would I begin?
> >2) I have some pool pumps that I would like to take
> >off the grid and reduce some of my summer bills by
> >creating a simple circuit to run the pumps from PV
> >can it be done and how?
> >I appreciate any feedback and I look foward to meeting
> >some of you at the meeting at TSU
> >Noyes Livingston
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