Posted by David Lesher on June 30, 2010, 9:04 pm
Grundfos makes a line of well pumps, SqFlex, that are designed
to run from PV panels; they arer designed to accept a range of
I'm seeking a circulator pump line of the same ilk. The task is
to use a PV-powered pump to push the water from the direct solar
array to the house and back.
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Posted by wmbjkREMOVE on July 1, 2010, 2:10 pm
On Wed, 30 Jun 2010 21:04:05 +0000 (UTC), David Lesher
If you want all the benefits of the SQFlex (such as AC and DC input),
then you could install one in a tank, or at least in a column of
water. I'm pretty sure it would be OK on its side if needed, that's
how the somewhat similar Grundfos constant pressure pumps are
Other options are pumps on this page
http://store.solar-electric.com/sun-pumps.html , or use one of the
solar controllers such as this model
http://store.solar-electric.com/pca-30-m1d.html on a single-voltage
pump of your choice.
Posted by Ecnerwal on July 1, 2010, 3:59 pm
Really - a $500 circulator pump. And one that can't handle hot water,
better yet? Not a particularly good plan, that.
Plenty of DC circulators out there, and if you want AC (which you
generally don't, with a solar thermal / solar PV combination, where less
sun automatically means less pumping, and more means more, very nicely)
a DC power supply would run you a lot less than a super-spendy pump that
wants to live in a nice cool well.
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Posted by wmbjkREMOVE on July 1, 2010, 7:58 pm
On Thu, 01 Jul 2010 11:59:17 -0400, Ecnerwal
I didn't stop to think of what the OP was using the water for, but I
see now that you're right to assume it's for water heating, which the
Flex definitely isn't suited for.
Depends on the app. Some people place a high value on being able to
unplug any-voltage DC, and plug in any-voltage AC (usually from a
generator), in its place. Anyway, apples and oranges. The SQFlex is
for cold water up to IIRC, 600' of head.
I used a differential controller, which allows close control and
circulation freeze-protection if needed. Plus, cheaper overall, even
on a PV powered home. Although that may not be true anymore now that
PV is so much cheaper.
Those look sweet. Not sure if they might have been sufficient for my
own circulator apps. Pricey though, I'm happy that I was able to use
standard AC models since I needed 4 of them. Seems like they were
about $00 each back then for 3 speed models.
Posted by MickyJf on July 1, 2010, 6:57 pm
Hi - Not sure on the parameters of your application, and as another
poster pointed out a DC pump would marry up with a DC supply from a
PV. panel much easier and simpler, also providing a steady pump rate /
power supply - without any loss or variation in the pump speed.
This is from my 'basic' knowledge of the technology - but I do come
accross a variety of Grundfos pumps in my day to day work.
However the reason I choose to post some info. / suggestion, I've come
accross another gentleman / poster in this discussion group that has
some alternate ideas surrounding pumping / solar / pv etc.
Morris Dovey is the mans name and his website explaining the
technology (which seems to be open source / co-operative development
technology) is DeSoto www.iedu.com
Here are some links / URL's to the pages that might interest you:
Worth having a look at if your trying to use the power of the sun to
pump a fluid from one place to another.