Is this changed domestic hot water system design going to work ok?

[nicktf]

Hi,

We are having PV panels fitted which will dump the excess energy into our hot water tank. Our house originally had a large 210L economy7 hot water tank (cold tank in loft), but the hot water tank died 18 years ago. At that time we fitted a smaller 117litre tank and went for fitting electric showers to reduce the hot water usage, and its been ok.

But now with fitting PV I'm thinking a larger tank is the way to go, especially as I want to dump the electric showers and go for mixer shower in the main and ensuite bathrooms to make use of the PV heated water. I'm fairly certain the smaller tank wont cut it (4 adults, 10 min shower each at 6L per minute is 240L. A 50% cold mix would take 120L out of a 117L tank!)

I was intending that the 210L hot tank would only use the lower immersion heater position. The immersion heater would be fed by the solar (iboost) diverter combined with the standard immersion heater feed (the non economy7 feed). I would then put the standard immersion heater feed on a time switch to use the economy7 rates. Hopefully this would allow the solar to heat the tank during the day and then be topped up by the economy7 at night when required, and that this arrangement would fully service the house for showers and washing up etc.

Any thoughts or comments, on the merits or flaws of this design really appreciated before I shell out my money!

Regards
nick

 

[king of pipes]

Yes that would work in my opinion not a expert in solar but I have worked on a few and fitted some . Just make sure you use good quality products and heat proof cables some immersion heaters are not very good quality . Kop