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How many panels ? ( to run 230 volt sprinkler pump 30 minutes a day?) - Page 20

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Posted by Morris Dovey on July 18, 2008, 1:06 am
bealiba@gmail.com wrote:

It's moving slowly - but as fast as resources permit.

I think we've improved efficiency significantly of both engines by
reducing the volume of the cold head and using fin tube to better
dissipate heat. With baseboard radiator fin tube, the cold head stays
surprisingly close to the ambient temperature.

I think it may be possible to improve still more by inserting a flow
restricter at the cold head end of the regenerator tube, but haven't
tested the idea yet.

I've managed the beginnings of a software model and written some design
tools so that we'll (finally!) be able to actually design a working
fluidyne instead of spinning our wheels doing "cut and try".

We're still fighting to get heat into the hot head of the
low-temperature engine. It's looking as if the best answer is going to
involve a custom extrusion, so we're trying everything else we can think

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA

Posted by wmbjkREMOVE on July 18, 2008, 12:21 am
On Thu, 17 Jul 2008 16:12:06 -0700 (PDT), bealiba@gmail.com wrote:

Huh? It doesn't matter what was originally posted. If you can spec a
solar pump for a typical need such as 8gpm and 80' head, then let's
see you do it. With specifics, not idiotic "so and so makes one"


Posted by Ron Rosenfeld on July 18, 2008, 12:14 am

The only thing he posted was "I need to calculate how many solar panels I
need to run 230 volt sprinkler pump 30 minutes a day. The pump runs at 2500
watts. The location is Kilauea, Kauai Hawaii.

"Assume for instance the panels are 50 watt, 17 vdc, 2.94 amp

"How do I calculate how many panels I will need?

He wasn't asking for system design or any other alternatives.  And he never
posted back.

I pointed out that some form of energy storage would be required.  And
you're certainly correct in your implication that that information would be
required if we were starting from scratch to design a system.

What would it cost my neighbor to purchase your system to meet these

He is presently using a fossil-fuel generator to power a pump to move water
from a well to some storage tanks on top of a hill.  His location is
eastern Maine (you could use Caribou for insolation data); he has a water
requirement from May-Sep of 1100 gal/day (consumption) and a required lift
of about 150 ft.

Posted by bealiba on July 18, 2008, 12:27 am
Tweedledee, you are an idiot. For further information: www.conergy.us

Posted by Morris Dovey on July 18, 2008, 1:06 am
 Ron Rosenfeld wrote:

Heh - if it'd been me I'd probably have dropped the ng after the first
two dozen responses.

I kept quiet because he appeared to prefer a PV solution and because I
don't know enough about PV systems to contribute.

I'm not offering it for sale until I feel like I have something worth
buying. Until then, he's welcome to copy and improve on anything I've
put out on my web site. I'd guess that if he's handy he could build
pumps and collectors for under $k, and never need to run his generator

It's unlikely that 150' rise will be a problem if the pumping is staged,
and the rise between stages will depend on collectors (which determine
input power) and the size and efficiency of the pump engines. A total of
1100 gallons per day only requires an average of 183 gallons/hour if we
assume 6 hours/day of sun.

Probably be a good idea to use anti-freeze in the working fluid. :-)

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA

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