Re: Trying to understand my solar water heating system...
I agree with Icarus and BB in their posts. Trying to resurrect an old, possibly warn out system could well be a huge waste of time, money and energy.
My personal way of thinking, for my situation is to KISS. (Keep It Simple Stupid) I'm lucky, was able to build and install my own flat plate solar water heater and position it on the South facing wall, (outside of course) below the 60 gal storage tank (located inside of course and extremely well insulated), and this allows direct heating of the potable water, no pumps, no heat exchangers etc. The down side? I do have to baby-sit the outside panel during the colder seasons and drain it if necessary, but that's not a problem all Summer long, and in Wnter, it stays drained and the water is heated from the wood stove instead of the sun. BTW, the storage tank temperature last evening was 160F at the top and 150 F at the bottom, so scalding is something we must be aware of. This morning, before the sun hits the panel, the temps are 155F top and 145 bottom. I don't waste hot water, but use what I need and have not been without hot water for the last year. There is an electric heating element in the tank, near the top, but I've never used it. Never.
It truly boggles my mind when I look around at my neighbors and how they have no idea the energy waste they live with. On the other hand I'm sure many of them think I'm weird.
1000 watts PV, MX60; micro hydro feeding Morningstar TS-MPPT-60 and producing over 175 watts 24/7 after all losses; 2 SureSine 300; Xantrex Pure Sine 1800/12; six L16 @ 12 volts.