Normal electric boiler + hot water solar panel as a pre-heater?

[rickj]

Living in the south of Spain - I have looked at a commercial solar hot water system with a panel plus tank combination, but all in all it's not exactly a cheap system, while we are only a two-person household with not much hot water use. We shower a few times a week for a few minutes, that's it. We have a pool you know.

Would it be a (good) idea to just install a regular electric boiler (80 liters or so), but as an extra a (DIY) solar hot water panel that simply uses that boiler as the storage? This way the water would be pre-heated during the day. Of course I will add a valve so the circuit cannot feed water into the mains water supply. And I'll add circuitry that will make sure no heat is drained from the storage. (I can program Arduino).

Thanks for any input!

rick

[J.P.M.]

For that much (or little) hot water use, provided the electricity is available and reasonably reliable, I'd skip solar altogether for supplying potable hot water for showers.

If that's your main/only hot water load, because of what sounds like relatively infrequent use, most of the energy supplied by a "preheating" panel will go to maintaining a tank temp. when it'll mostly be lost anyway. I'd stick with the 80 l/20 gal. electrically fired tank and fire it up an hr. or so before a shower, or put it on a timer, etc.

I would however, give solar energy use consideration for pool water heating, but then only after getting and using a pool cover - much less expensive.