On 20/05/2021 22:32, newshound wrote:
On 20/05/2021 17:33, The Natural Philosopher wrote:
On 20/05/2021 16:05, Tim+ wrote:
The Natural Philosopher wrote:

In reality a CCGT and a CH condensingÂ* boiler are both about 65%
(thermal) efficiency : the kicker is that heat pump is, in terms of
heat
out to electricity in, at least 200%, and up to 400% 'efficient'.

That means that overall CCGT plus heat pump is a less energy intensive
heating solution than a gas boiler.

How does that compare to a gas powered domestic heat pump?
Presumably that
would out-perform CCGT + electric heat pump?

Tim




I would not have thought so. Otherwise we would all be using gas
fridges, not electric


We don't use gas fridges because we don't (yet) have mini gas turbines
to drive the compressor. The old fashioned gas fridges were the
"absorption" type, much less efficient than modern ones.

When the CEGB was privatised, one of the managers was going to use his
redundancy payout to try to adapt lorry turbocharger technology to make
a "home" system to generate domestic electricity and use the waste heat
for DHW and central heating. I helped him to scrounge some laboratory
C&I stuff that was otherwise going into a skip for him to start making
prototypes. I guess it never got anywhere, but I was always slightly
sorry about that. It seemed to me to be a scheme with potential
(although probably better in colder climates with a more consistent CH
requirement).

One of the problems with model plane gas turbines (jets) is that the
blade to cowl clearance has to be about the same as it is on a full size
jet, but proportionately this is a far larger percentage of the total
blade diameter, and this leads to serious loss of efficiency.

Pocket size gas turbines simply are not as good as big ones. Small may
be beautiful, but big is often better.

Remember that having ones own generator stopped being useful about the
time the last windmill stopped turning.

Before modern insanity set in

--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain