Pump Efficiency

[chem geek]

Mark,

So with the 4x160 I would set up two programs, one for solar on that had an RPM that produced a GPM of 48 (that I must calculate from the pump curves and my pressure reading converted to head in feet plus add the estimated suction loss), with the other program for solar off that was set for a worst-case of 8-hour runtime (since that's how long my solar could effectively be used for heating) for 1 turnover which is 16,000/(8*60) = 33 GPM. I would switch between the two automatically based on my existing solar thermostat (which already outputs to a Jandy automatic switch so could also output to the 4x160 via IntelliComm).

With the full IntelliFlow, the "filter" program would be set at 33 GPM while I would have a "feature" for the solar that was set at 48 GPM and would be triggered (via IntelliComm) by the solar thermostat. So my worst-case energy waste with the 4x160 vs. the full IntelliFlow is when the solar is on for a full turnover, so 16,000/(48*60) = 5.5 hours at which point, assuming the water is warm enough (so that the solar shuts off), the Intelliflow shuts off completely for the day. That comes to an energy waste with the 4x160 of (8-5.5) = 2.5 hours running at 33 GPM. This is probably a few hundred watts so about $6 per month or so.

Of course, with the full IntelliFlow I also get the flow meter so don't have to try and estimate (possibly inaccurately) my flow rates using pump curves and the pressure gauge. And it will be more flexible if flow rates change for any other reason.

Whichever way I go, this will really make that booster pump for the Letro Legend really stick out with its wasteful 1470 Watts, even though it doesn't run as often. I can't even use another IntelliFlow 4x170 for this application since it apparently requires 50 PSI (115 feet of head) at 12 GPM. It's really too bad there isn't a more efficient pump for this purpose. I've looked at vacuum cleaners instead, but they vacuum to my filter and not to a bag so that's a hassle for cleaning. I've also looked at automated cleaners (probably the most energy efficient option), but they require a 24V power cord going into the pool which is a separate hassle. About all I can do is to reduce my cleaner run times as much as possible, unless you have some suggestions.

Richard

P.S.
I thought of another reason why the flow-metered IntelliFlow would be better. In my calculations for the solar, I was assuming steady state, but in fact during the priming of the solar an additional 15 feet or so of head is present and that would require a higher RPM to attain (even at a lower GPM -- the curves are somewhat "flat" at constant RPM), but this extra RPM (and energy) would be wasted (and lead to higher flow rates than needed) once priming was completed. Looks like the full IntelliFlow is the way to go for my system.