Think it's practical for a system where the only input is purely solar?
When I do mine, I probably won't include an ICE generator in the mix, mainly because the genny I have is already established and is air cooled. It hardly ever gets run, and honestly I burn more gas just keeping it clean than I do for real world production (read 'emergencies') - I'm not off grid by any means. It's there to run the fridge primarily when the grid goes down, and to run space heaters in the winter during the same. Not much more. Probably could handle one of the A/C units if things were desperate...
So in my case, I would only be dumping the extra collector input.
I guess I should reword the question, as I can clearly see that it would be practical. What I really want to know is, what would be the sweet spot for the ratio of collector to storage with such a layout?
Going by what I like to see with the PV that I have, psychologically, I am 'happier' the more the dump load is dumping. Something about knowing that the juice is there no matter what. For water, I'd really like to see the same thing. As I mentioned before however, I wouldn't be so inclined to design a
large scale PV system this way. The margins would be much tighter due to the cost of the panels.
But for DHW? Why not?
I won't be able to dump into the ground; the cost of doing so would be prohibitive in my situation. I will probably be stuck using something like an engine radiator (typical car comes to mind) to waste the excess.
One thing worthy of mention - I would not be using it for space heating (just yet), although with the radiator design I could set up a set of damper boxes and route the heat inside if I felt froggy enough for the winter months.
Am I pretty close in guessing around 5ft/gal? Or higher? Is 10 worthwhile to consider so that even winter means there is always plenty of hot water available (just as it is on-grid)?
My guess is 5 sq ft... ?
Steve