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Using excess solar to help with central heating

Started by Aussie_Pete, February 27, 2022, 09:04:26 AM

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Hello all from a solar & battery newbie,

I'm currently getting a 5.2kwp solar PV system and linked 7.2kwh battery on my house in Scotland. I've been researching for about 6 months and the system is due to be installed this month.

I've been looking at what technologies are out there to exploit excess solar once the batteries are charged. I'm aware of heating water using an Eddi or I-boost, charging an EV using a zappi, but was wondering if anyone had considered installing an electric flow boiler (like the Trianco Aztec) on their existing central heating system, driven by excess solar to reduce cost of central heating? It seems to be a relatively new technology, but when integrated with solar to add heat to the central heating system it could significantly reduce gas or oil use for central heating.

For clarity, I'd be considering installing in addition to the existing oil or gas boiler, so that when there's excess solar this would heat central heating and when there's not solar the gas or oil boiler would run heating

Peter on the south coast

I do not think you will have enough electricity to do this.

Have a look on PV Output (Aussie site so you might be familiar) which holds data for PV all over the world and see what people near you are getting. Gas boilers are still really chaep compared to any other. An EV will absorb all your excess I suspect.



Hi Pete
I am in the South of England. I had the sane thought and immediately bought a cheap little room heater once my solar PV6kwp +battery10kwh +iBoost was installed last month.
In practice there have been few days when there has been both demand and supply to match and now my heating is off for the summer anyway. Demand is mostly in the morning whilst supply after the battery is charged is in the afternoon.
I found that I'd watch the system like a hawk, turn on the room heater, only for the sun to go in and the battery start to be used, or the hot water doesn't heat instead. So essentially my system doesn't have enough intelligence either.
I am working on a solution for next year a bit like you suggested that's compatible with the boiler and uses the second appliance outlet from the iBoost. I'll be honest it's not that high on my list and the complexity is not the gadget itself but intelligence is very tricky I.e working out forecast weather versus battery state versus hot water.
I would suggest more basic stuff , sorry but insulation insulation insulation.  Do keep in touch for next season.