In article ,
Max Demian wrote:
On 18/05/2021 13:41, Dave Plowman (News) wrote:
In article ,
tim... wrote:
"Jim GM4DHJ ..." wrote in message
...
https://www.bbc.co.uk/news/science-environment-57149059

yup

banning gas boilers only makes any sense when 100% of UK electricity
production is carbon free

It can make sense to reduce local pollution.

until it is, simply transferring gas use to additional electric use is
just daft

What is daft is charging a higher price per kilowatt of electricity than
gas.

That's mostly down to the second law of thermodynamics.

Efficiency = (input temp - output temp)/(input temp) for a heat engine.

A gas power station is 30-50% efficient, the rest being waste heat
unless you can use it for something like district heating.

If that is the case, burning it directly to heat our homes etc makes more
sense.

--
*When it rains, why don't sheep shrink? *

Dave Plowman London SW
To e-mail, change noise into sound.

On 19/05/2021 13:57, Dave Plowman (News) wrote:
In article ,
Max Demian wrote:
On 18/05/2021 13:41, Dave Plowman (News) wrote:
In article ,
tim... wrote:
"Jim GM4DHJ ..." wrote in message
...
https://www.bbc.co.uk/news/science-environment-57149059

yup

banning gas boilers only makes any sense when 100% of UK electricity
production is carbon free

It can make sense to reduce local pollution.

until it is, simply transferring gas use to additional electric use is
just daft

What is daft is charging a higher price per kilowatt of electricity than
gas.

That's mostly down to the second law of thermodynamics.

Efficiency = (input temp - output temp)/(input temp) for a heat engine.

A gas power station is 30-50% efficient, the rest being waste heat
unless you can use it for something like district heating.

If that is the case, burning it directly to heat our homes etc makes more
sense.

It always is unless a zero carbon way of generating electricity is used.

--
Max Demian

On 19/05/2021 23:16, Max Demian wrote:
On 19/05/2021 13:57, Dave Plowman (News) wrote:
In article ,
Â*Â*Â* Max Demian wrote:
On 18/05/2021 13:41, Dave Plowman (News) wrote:
In article ,
Â*Â*Â*Â* tim... wrote:
"Jim GM4DHJ ..." wrote in message
...
https://www.bbc.co.uk/news/science-environment-57149059

yup

banning gas boilers only makes any sense when 100% of UK electricity
production is carbon free

It can make sense to reduce local pollution.

until it is, simply transferring gas use to additional electric use is
just daft

What is daft is charging a higher price per kilowatt of electricity
than
gas.

That's mostly down to the second law of thermodynamics.

Efficiency = (input temp - output temp)/(input temp) for a heat engine.

A gas power station is 30-50% efficient, the rest being waste heat
unless you can use it for something like district heating.

If that is the case, burning it directly to heat our homes etc makes more
sense.

It always is unless a zero carbon way of generating electricity is used.

The problem with wrong assumptions is that they lead to wrong answers

1. A gas power station is in the range of 40-70% efficient
2. Not all the heat from a heat pump comes from the electricity. A lot
of it comes from the air or soil outside
3. Not all the heat from a central heating boiler goes into the hot
water. Some goes out of the flue as hot gasses at slightly below 100C.

In reality a CCGT and a CH condensing 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.

making your statement plain wrong




--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

The Natural Philosopher wrote:

In reality a CCGT and a CH condensing 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




--
Please don't feed the trolls

On 20/05/2021 16:05, Tim+ wrote:
The Natural Philosopher wrote:

In reality a CCGT and a CH condensing 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


--
No Apple devices were knowingly used in the preparation of this post.

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?Â* 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).

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

newshound wrote:
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.

And the primary advantage of electric heat pumps is you can run them off
renewables, which you couldn't do with a gas heat pump.

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).

'Combined Heat and Power' is a thing you can buy today:
https://www.thegreenage.co.uk/tech/chp-boilers/

The problem is generally modulating down - they really want to be run full
blast, but that generates too much heat for a domestic setting. Even in
cold climates, you would be much better off insulating. They might be fine
for something like a swimming pool where there's a constant predictable
heat demand.

Theo