Hi Lee, I would think a "snap-shut" valve, such as a Hudson valve in each tank and a pressure switch hooked up to the float terminals on the controller would work well in this situation.
Good luck! Mark Dickson Oasis Montana Inc. <http://www.oasismontana.com/> <http://www.oasismontana.com/> www.oasismontana.com www.grid-tie.com <http://www.grid-tie.com/> <http://www.pvsolarpumps.com/> <http://www.pvsolarpumps.com/> www.PVsolarpumps.com _____ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Lee Bristol Sent: Thursday, June 11, 2009 1:26 PM To: RE-wrenches@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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