Is using roof water and a cistern out of the question?
_Drake Chamberlin_
_Athens Electric LLC_
_Ohio Electrical Contractor's License 44810_
_NABCEP Certified PV Installation Professional_
---
On 2025-05-08 15:36, Jason Szumlanski via RE-wrenches wrote:
Water pump is not my strong suit. I usually leave that up to the
experts around here. Unfortunately, the experts are clueless when it
comes to off-grid living. I have a client with a setup that is pretty
unworkable. I'm trying to give him some general guidance.
The setup uses a brackish water (might as well be salt water) very
shallow well. It is about 3 ft underground for the water table. The RO
system installer has a 1 HP 1.25 SF Century centrifugal surface pump
drawing water from the well and pressurizing the inlet of a StaRite
1.25 HP booster pump designed for about 10 GPM at 150 PSI to run water
through the RO system.
Both of the pumps run simultaneously and continuously when producing
water, and the water production is ridiculously low. I understand that
RO production is going to be slow, but the amount of power these pumps
are using is pure insanity. I have advised the client that, at a
minimum, this system needs to be on a smart load circuit to run only
when there is adequate battery capacity. The startup surgery is not a
concern, but it does flicker the lights and it makes quite the racket.
My thoughts are that the well pump is drastically oversized. The
booster pump only needs 10 gallons per minute, and it has a suction
head of 15 ft. I don't even know if the well pump pressurizing the
booster pump inlet is required. I'm thinking we should be slow pumping
water into an interim holding tank at least at the height of the
booster pump. At a minimum, the well pump should be on a pressure
switch with pressure tank so it can cycle.
Can anyone give me some general guidance, and perhaps a VFD pump that
does not have the startup surge and is maybe more efficient? During
times of heavy use, the RO system can easily eat up half of the PV
produced during a day at this site.
Jason Szumlanski
Florida Solar Design Group
_______________________________________________
List sponsored by Redwood Alliance
Pay optional member dues here: http://re-wrenches.org
List Address: [email protected]
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
There are two list archives for searching. When one doesn't work, try
the other:
https://www.mail-archive.com/[email protected]/
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
http://www.re-wrenches.org/etiquette.htm
Check out or update participant bios:
http://www.members.re-wrenches.org
_______________________________________________
List sponsored by Redwood Alliance
Pay optional member dues here: http://re-wrenches.org
List Address: [email protected]
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
There are two list archives for searching. When one doesn't work, try the other:
https://www.mail-archive.com/[email protected]/
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
http://www.re-wrenches.org/etiquette.htm
Check out or update participant bios:
http://www.members.re-wrenches.org
