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Are Solar Diverters Necessary for Homes with ASHPs and Solar PV?
I do the same, 250L tank heated to 47C overnight, no reheat required to get us through a normal days usage.
I've had an iBoost for 6 years. In total it tells me I've 'saved' 2400 kWh to date. For the first 4 years it did a reasonable job of heating the water during the summer leaving me with minimal gas bills. Since buying an EV two years ago then installing a Powerwall last February the amount of savings have dropped (of course). The Powerwall is charged first and then the water. Having said that today, overcast but with PV generation, the iBoost is currently heating the water. The PW is now at 100% but there is not enough PV output to warrant plugging in the car. The iBoost has more than recouped its purchase cost if you assume an average electric tariff over that time. If you use an average gas tariff then it's a moot point - however it has saved CO2 emissions. I'm on IOG so do not use the iBoost overnight. The saving is marginal. It would make no sense to have one with an ASHP - unfortunately Octopus have declined to fit one (apparently I need a 14 kWh HP and they only supply up to 11 kWh). If/when the iBoost fails I will not replace it. There would likely not be any payback during its life.
Ideal HP290 14kw heat pump, 2.99kw PV, Powerwall 2, Zappi charger, EV. Midlands location hybrid house part 1911, part 1970, part 2020s.
The installer of my heat pump gave me that exact advice. Forget my Eddi and use the heat pump. My wife? "I don't care. I like the hotter showers". Happy wife, happy life
@zzxap19 that's a fair point. With the eddi, is it possible to set the diverter to only kick when the HW cylinder is at a certain temperature. That would be ideal. Allow the heat pump to efficiently get it to 45C, and allow the diverter to take over from there to 50C and beyond.
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@andris you mentioned a cover for your HW cylinder. Did you buy one?
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@editor No, I made one 😀
Loft insulation all around, then put an old curtain around it to seal the fibre glass. It is located under my stair case inside the house. Not the best as it is a horizontal tank. But I have definitely halfed the heat loss even though it is inside the house.
16kw Samsung TDM ASHP. 8.4kw PV, power optimizers 20×420watt panels 6kw SolarEdge inverter.
Ideally you could put that power through the heat pump, but I haven't yet found the controls with sophisticated enough logic to do that. Any one else seen any good ones?
It is a decision on what you prefer/ your situation, do you get a good export rate for your electricity? If so, export to the grid. If not, use as much as possible at home and put it in your hot water tank!
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