We currently have an ashp, its been installed about 6 years, so the rhi payments will soon be coming to an end after 7 years.
We already have a 12kw solar system, with Eddi water heating with surplus, I'm going to add another 8kw of pv in the next few weeks but in winter months this still is no where near enough especially during the night and early hours when most the power is needed.
I'm contemplating adding in a gas or oil boiler to help the system when it's really cold, as the house struggles to get up to temperature when weather is consistently below a couple of degrees.
The other winter our electricity bill was over £1000 for one month, with the log burner on at every opportunity, so it feels like burning money maybe a cheaper way to stay warm.
If adding a small combi boiler to the system for use in colder temperatures, say below 5 degrees, is it best to feed hot water directly into the system, or would it be more efficient to pre heat the air going into the ashp?
I was thinking this could be done with a simple arrangement of large vehicle radiators (heat exchanger) in front of the heat pump heat exchanger.
My thought was this would stop the constant defrost cycle being required but the rest of the system could operate as normal, and if over the preset temp would just pull ambient air through this new primary heat exchanger.
The existing system would not need any reconfiguration or change over and the new fossil fuel element would not be critical but a boost.
At a later date if this worked the hot water side of the system could have some direct input during these periods, when the solar and Eddi unit is not helping us out.
If anyone has any experience or thoughts on this it would be appreciated.
Similarly if anyone can recommend any trend systems that on a sunny day with cold night ahead could harvest any spare energy? I've read thermal stores or buffer tanks are not recommended for ashp applications. Our existing ashp controller is a fairly basic samsung model with very limited Integration.
Next on my list is a small hydro electric setup, but this will take a little more work!🤔
