"Andrew Gabriel" wrote in message
...
In article ,
"Doctor Drivel" writes:

"Andrew Gabriel" wrote in message
...

The only time the boiler runs at 25kW
(where it could run a stirling enging) is for about a minute
when it's first switched if the radiators are stone cold.

About a minute? Look again.

They were meant to be combis, where
they run at full belt when the taps are
on.

So how long do you keep your hot water running?
(For the purpose of this question, you can discount
any burst pipework;-)

It is "seasonal" performance that matters. In summer they will still be
producing electricity (combi or not) and pumping that into the grid, which
will be used by local consumers with less line losses and hence higher
efficiencies.

First thing in the morning when the combis are at full belt in heating
before modulating down, and also full belt in DHW, is also the time when
there is also high electricity demand. The peak usgage of both coincides.
microCHP will level off the peaks of electricity demand. microCHP makes
sense in new housing estates. If millions are installed then they will make
a significant impact. It is clear not so many new power stations would be
built, and probably eliminate the nuclear option.

Like I said, useless.

You need to think it through.