[RE-wrenches] Design help for solar water pumping application

Allan Sindelar allan at positiveenergysolar.com
Thu Jun 11 13:28:04 PDT 2009


Lee,

You can get Grundfos' WINCaps software from your RE or pump supplier; some
will run the sizing for you (Jeremy at Conergy does for us). I didn't check
your head and flow, but I would expect that's about your only good pump
choice at that head. Add a tracker if you need greater summer output; don't
attempt batteries as a solution. If usage occasionally exceeds output, add
an IO101 control and allow the pump to run off any AC source at night. A
tiny 1,200W inverter/generator will work at sea level. Use a CU200
controller to allow a float or level detector switch to turn off the pump
when tanks are full. Mercury-based float switches last longer in signal
circuits that carry no current. If you can't use a float switch because the
lines are already buried, look into www.P2Flow.com <http://www.p2flow.com/>
for pressure transducer-based control. Read the website info, then call
Britt there with your specific application. That array sounds oversized, as
the pump draws a maximum of 900 watts. Hope this helps.

 

Allan Sindelar

 <mailto:Allan at positiveenergysolar.com> Allan at positiveenergysolar.com

NABCEP Certified Photovoltaic Installer

EE98J Journeyman Electrician

Positive Energy, Inc.

3201 Calle Marie

Santa Fe, New Mexico 87507

505 424-1112

 <http://www.positiveenergysolar.com> www.positiveenergysolar.com

  _____  

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Lee Bristol
Sent: Thursday, June 11, 2009 1:26 PM
To: RE-wrenches at lists.re-wrenches.org
Subject: [RE-wrenches] Design help for solar water pumping application

 

Solar Water Pumping Wrenches,

 

We normally don't do solar water pumping but a friend asked for some help
designing his system.  He has one well and two 5,000 gallon reservoirs to
fill up.  The average usage is expected to be about 2,000 gallons per day
but may be higher in the summer.  The tanks will have level detector
switches to sense when the tank is full.  The site is near Leesburg, VA.

 

The problem is to design a control system to turn on the pump when one or
both of the tanks needs water and to shut it off when both are full.  The
closest tank has a head requirement of 200 feet (pump to tank) and is 300
feet from the well head.  The second tank head requirement is 220 feet and
it is 3,000 feet from the well.  The pipes are expected to be 1.25 or 1.5
inch.

 

A Grundfos SQFlex 6 SQF-2 pump with 1.36 KW solar was recommended, 360 foot
head, 360 gph.  I think that this would provide the lift but not the
quantity.  Hmmmm, what valves and controls would you all suggest?

 

Thanks!


Lee


-- 
Lee Bristol
NABCEP Certified Solar Designer/Installer

Chief Technology Officer
Standard Solar, Inc.
202 Perry Parkway, #7
Gaithersburg, MD 20877
(301) 944-5105
(240) 479-1510 (c)
www.standardsolar.com

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