I didn't get much help from the tech from the solar company that came out to ensure our 550 ft of heliocool solar panels was up and running (11 x 50ft panels, elevated 23-28 ft from the pump - the panels are spread across multiple roof sections). I have 3" main plumbing plus I think 2 or 2.5" plumbing on the roof and a single intelliflow vs+ pump. I do not have a flow meter yet.
Pump is on from 7am - 7pm, and solar is activated via roof temperature sensor and thresholds defined in our intellitouch automation controller.
I've confirmed that solar flows and bubbles disappear eventually with a pump rpm at 2400 or higher (haven't tested <2400rpm). At 2400rpm, the filter (quad de 100) pressure is roughly 14.5. I'm assuming our total head is somewhere between 40-55 but this is just based on guesses and various equations I've seen posted here on tfp or elsewhere. Unfortunately, I don't currently have any way to calibrate gpm.
Assuming the panels have an optimal gpm of 5 per, or 55 gpm total and that my goal is to keep solar panels running most of the day at the lowest reasonable gpm which generates the least noise and uses the least power while producing modestly efficient heating (even if suboptimal) - what rpm should I set the pump to?
I've tried 2400 and 2500rpm over the last few days and the results haven't been that great, we got a good bump from 51-55 degrees F one day but since have yet to exceed 60 degrees, mostly going up a few degrees during the day and losing nearly all of that at night. Yes, I'm in San Diego.
Solar heating will be supplemented by a safety pool cover being installed next week and a heat pump which we're troubleshooting. Solar will be the main heat source for the pool though. I understand winter won't produce swimable temps but am still trying to calibrate and work out kinks with the system prior to the start of our season in mid february.
I did some more calcs tonight, and while I can guess the optimal setting is somewhere between 2500 - 2750, I'm not sure what the lowest rpm I should use while still providing reasonable heating (as I am using an intelliflow pump, I am happy to just run the pump longer at a lower rpm - but it's unclear what the proper pump speed should be and there is a huge difference in noise and energy use of the pump between 2500rpm and 2750).
Any help/advice appreciated.