DIYbanter - View Single Post - Anybody created a pre-heat DHW cylinder

Alan Braggins

In article , wrote:
A typical sub 4kw domestic array will only be generating a few kwh units each day during the winter months

He could be planning it now to use next summer.

I've considered doing something similar. My thermal store is two cylinders
in parallel, with both DHW and UFH being heated by them. But the remaining
failed old Nu-Heat UFH is being replaced by radiators (upstairs was done
a while ago), so my half-plan was change the stores to series, and make the
lower heat exchanger on the first one a heating coil connected to
(hypothetical) thermal solar panels.
Or, with all the UFH now gone, both lower coils could be repurposed as solar,
but in conditions when the boiler will be needed anyway, having one cylinder
as lower temperature preheat seems to make sense for the same reasons as the
OP.

(The stores do have immersion heaters as backups, so PV panels could
also be used in the same way as the OP.)