On 16/06/2020 17:41, wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for any waste energy to go. Thus energy input & energy output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in the traditional
definition "the ratio of the useful work performed by a machine to the
total energy expended". On that it's entirely reasonable to consider
how a radiator in a CH system affects the ratio of the energy released
where it's wanted to the total energy expended (i.e. including all the
energy released where it's not - e.g. in the boiler, pump, and pipes
under suspended floors).

Looking at it another way, I'd consider a radiator which took water in
at 70 degrees and passed it out at 65 degrees to be less efficient than
one which passes it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is that I was
trying to stop the post growing even longer. Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good thing to
have at least the option of warming the room faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.


--
Robin
reply-to address is (intended to be) valid

On Tuesday, 16 June 2020 13:37:29 UTC+1, Robin wrote:

If the new boiler ever arrives here I'm planning on putting fans under
the radiators in some rooms until redecoration allows new (and sometimes
relocated) radiators. I couldn't find evidence of how to quantify the
effect but a trial with 3 x 100mm PC case fans (under-run at 9V) seemed
to have some benefit.

Years ago I got I think 2C room temp increase from a 4" pc fan. I suspect fanned rads will make a comeback some day once people realise they can have a much smaller rad without all the fan noise of the old ones.


NT

On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for any waste energy to go. Thus energy input & energy output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in the traditional
definition "the ratio of the useful work performed by a machine to the
total energy expended". On that it's entirely reasonable to consider
how a radiator in a CH system affects the ratio of the energy released
where it's wanted to the total energy expended (i.e. including all the
energy released where it's not - e.g. in the boiler, pump, and pipes
under suspended floors).

Looking at it another way, I'd consider a radiator which took water in
at 70 degrees and passed it out at 65 degrees to be less efficient than
one which passes it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is that I was
trying to stop the post growing even longer. Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good thing to
have at least the option of warming the room faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.

NT: useful energy out over energy in is the definition.

With a wet radiator there are only 2 places energy can go: into the room or out the outlet pipe. In neither case does the rad lose any energy, hence efficiency is 100%.


NT

In article ,
wrote:
Nothing is ever 100% efficient.

incorrect. Another example is an electric convector heater.

Not so either. A standard convector heater element produces light,
although likely outside the visible spectrum.

--
*Procrastinate now

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

On Tue, 16 Jun 2020 09:49:31 -0700 (PDT), wrote:

The system is highly complex ie not just a pair of pipes that goes
from
one rad to the next. There are rads on long spurs, with different
lenghts/bends for the pipes, spurs with rads connected overlapping
and
rad acroos the main pair. It makes the system very sensitive to
adjustments.

Ah, reality. I hope you didn't copy Steptoe's heating system

Nothing to do with me but the builder/carpenter who renovated the
place in the 80's. Knowledge of plumbing and heating systems minimal.
The thermostat was in the utilty room, without a radiator.

Though IIRC that was single pipe.

Single pipe might be easier to adjust. B-)

--
Cheers
Dave.

On Tue, 16 Jun 2020 09:53:42 -0700 (PDT), wrote:

I suspect fanned rads will make a comeback some day once people realise
they can have a much smaller rad without all the fan noise of the old
ones.

s/fanned/finned/ ?

--
Cheers
Dave.

On 16/06/2020 17:59:37, wrote:
On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for any waste energy to go. Thus energy input & energy output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in the traditional
definition "the ratio of the useful work performed by a machine to the
total energy expended". On that it's entirely reasonable to consider
how a radiator in a CH system affects the ratio of the energy released
where it's wanted to the total energy expended (i.e. including all the
energy released where it's not - e.g. in the boiler, pump, and pipes
under suspended floors).

Looking at it another way, I'd consider a radiator which took water in
at 70 degrees and passed it out at 65 degrees to be less efficient than
one which passes it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is that I was
trying to stop the post growing even longer. Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good thing to
have at least the option of warming the room faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.

NT: useful energy out over energy in is the definition.

With a wet radiator there are only 2 places energy can go: into the room or out the outlet pipe. In neither case does the rad lose any energy, hence efficiency is 100%.

Energy efficiency is always going to be 100% for a radiator.

Efficiency has several meanings. This might assist:
https://en.wikipedia.org/wiki/Effici...disambiguation)

For the avoidance of difficulty in comprehending English, this may also
assist:
https://www.oxfordlearnersdictionari...lish/efficient

Adjective: doing something in a good, careful and complete way with no
waste of time, money or energy

It doesn't just have to be time, money or energy. It could be weight or
area in respect of a radiator. A radiator may be more efficient
radiating heat if the water is at a higher temperature.

Some further examples
1) a highly efficient worker
2) efficient heating equipment
3) more efficient use of energy
4) fuel-efficient cars (= that do not use much fuel)
5) We offer a fast, friendly and efficient service.
6) This is simply the most efficient way to do it.
7) We must meet members' needs in the most efficient and effective ways
possible.
8) efficient at something As we get older, our bodies become less
efficient at burning up calories.
9) efficient at something - These magnificent animals were remarkably
efficient at survival.
10) efficient in something - Modern water boilers are highly efficient
in fuel use.
11) efficient in doing something - He was ruthlessly efficient in
acquiring estates.

There may be occasions where you might swap the word for effectiveness,
in many instances they are synonyms.

Perhaps English has moved on since you were at school?

On Tue, 16 Jun 2020 16:02:12 +0100, Phil Addison wrote:

The system is highly complex ie not just a pair of pipes
that goes from one rad to the next. There are rads on long spurs,
with different lenghts/bends for the pipes, spurs with rads
connected
overlapping and rad acroos the main pair.

I don't see how that invalidates the procedure, ...

But note that in some cases this will be impossible due to bad design of
the pipework ...

Perzackerly.

Thermal imaging camera allows you to see how much flow is (or
isn't!)
going through a rad by the size of the rising hot water column
from
the inlet. This also responds very quickly to any changes.

I haven't had the chance to use an IR camera, and can see it would be
helpful to see the immediate effect of a small turn of the valve, but I
emphasise that you don't want full flow in all the rads.

Maybe not but it enables you to setup an even starting point
relatively quickly and painlessly.

A common misconception is that increasing flow-resistance will make a
radiator cooler. Not necessarily: for a rad already getting as much heat
as it can dissipate, closing its valve a bit just makes the pump
increase its pressure so that rads further away get more flow.

No the rads with a lower flow resistance get more flow, they may or
may not be further away.

--
Cheers
Dave.

On 16/06/2020 17:59, wrote:
On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for any waste energy to go. Thus energy input & energy output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in the traditional
definition "the ratio of the useful work performed by a machine to the
total energy expended". On that it's entirely reasonable to consider
how a radiator in a CH system affects the ratio of the energy released
where it's wanted to the total energy expended (i.e. including all the
energy released where it's not - e.g. in the boiler, pump, and pipes
under suspended floors).

Looking at it another way, I'd consider a radiator which took water in
at 70 degrees and passed it out at 65 degrees to be less efficient than
one which passes it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is that I was
trying to stop the post growing even longer. Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good thing to
have at least the option of warming the room faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.

NT: useful energy out over energy in is the definition.

With a wet radiator there are only 2 places energy can go: into the room or out the outlet pipe. In neither case does the rad lose any energy, hence efficiency is 100%.


The inclusion of "useful" was good. But you then :

a. ignore the fact that not all the energy leaving through the output
pipe is "useful" if the rest of the system has losses (i.e. heat lost
where it's not wanted); and

b. assume that all energy released into the room is equally useful when
in many cases it's not because the idea is to make people in the room
/feel/ comfortable.

Measuring (b) is complicated and I don't pretend to understand all the
components. But a simple example is that a pure convector in a room
with a high, cold ceiling is not the best source. And I don't need to
as clever people have written BS 7726 (Ergonomics of the thermal
environment €” Instruments for measuring physical quantities) which
defines an "operative temperature". So my definitions of the efficiency
of a radiator would focus on how much it increases the operative
temperature for (a) a given (net) energy released by the radiator and
(b) the corresponding (gross) energy the system has to provide.

I stumbled across this subject some years ago when looking for evidence
about the claims for tall radiators - which do seem to have benefits for
a given area.

--
Robin
reply-to address is (intended to be) valid

On Tuesday, 16 June 2020 18:47:11 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
Nothing is ever 100% efficient.

incorrect. Another example is an electric convector heater.

Not so either. A standard convector heater element produces light,
although likely outside the visible spectrum.

Don't think I've ever seen an oil filled radiator style heater that emits light. As for bare element ones, some do some don't.


NT

On Tuesday, 16 June 2020 19:55:22 UTC+1, Dave Liquorice wrote:
On Tue, 16 Jun 2020 09:53:42 -0700 (PDT), tabbypurr wrote:

I suspect fanned rads will make a comeback some day once people realise
they can have a much smaller rad without all the fan noise of the old
ones.

s/fanned/finned/ ?

Not sure what that means, but they do tend to go together. A fan with a flat panel works for a diy job but is not optimal design costwise for a new product.

All you need for a fanned rad to work, take up way less space and be much preferred is silence, and that's not a challenge.


NT

On Tuesday, 16 June 2020 20:08:04 UTC+1, Fredxx wrote:
On 16/06/2020 17:59:37, tabbypurr wrote:
On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for any waste energy to go. Thus energy input & energy output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in the traditional
definition "the ratio of the useful work performed by a machine to the
total energy expended". On that it's entirely reasonable to consider
how a radiator in a CH system affects the ratio of the energy released
where it's wanted to the total energy expended (i.e. including all the
energy released where it's not - e.g. in the boiler, pump, and pipes
under suspended floors).

Looking at it another way, I'd consider a radiator which took water in
at 70 degrees and passed it out at 65 degrees to be less efficient than
one which passes it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is that I was
trying to stop the post growing even longer. Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good thing to
have at least the option of warming the room faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.

NT: useful energy out over energy in is the definition.

With a wet radiator there are only 2 places energy can go: into the room or out the outlet pipe. In neither case does the rad lose any energy, hence efficiency is 100%.

Energy efficiency is always going to be 100% for a radiator.

Efficiency has several meanings. This might assist:
https://en.wikipedia.org/wiki/Effici...disambiguation)

only one of which applies here, and that is:
Energy efficiency (physics), the ratio of power consumed to useful power output


For the avoidance of difficulty in comprehending English, this may also
assist:
https://www.oxfordlearnersdictionari...lish/efficient

Adjective: doing something in a good, careful and complete way with no
waste of time, money or energy

a usage of the word that applies primarily to a person's actions. 'with no waste of energy' certainly applies to radiators. Good & careful certainly have nothing to do with radiator efficiency.


It doesn't just have to be time, money or energy. It could be weight or
area in respect of a radiator.

sorry but no. The definition of efficiency in physics & engineering is useful energy output divided by input. That's just what efficiency is.


A radiator may be more efficient
radiating heat if the water is at a higher temperature.

Radiation from a radiator versus convection is irrelevant to its efficiency. That is more relevant to filament lamps.


Some further examples
2) efficient heating equipment
3) more efficient use of energy
4) fuel-efficient cars (= that do not use much fuel)
10) efficient in something - Modern water boilers are highly efficient
in fuel use.

those are of course the efficiency that we are discussing, useful energy output over input.


5) We offer a fast, friendly and efficient service.
6) This is simply the most efficient way to do it.
7) We must meet members' needs in the most efficient and effective ways
possible.

Generally waffly bs uses of the word


1) a highly efficient worker
9) efficient at something - These magnificent animals were remarkably
efficient at survival.
11) efficient in doing something - He was ruthlessly efficient in
acquiring estates.

again useful output over input, though used with rather less precision


8) efficient at something As we get older, our bodies become less
efficient at burning up calories.

not even true. Old bodies do become less efficient at doing work this calories, but not less efficient at burning them.


There may be occasions where you might swap the word for effectiveness,
in many instances they are synonyms.

Perhaps English has moved on since you were at school?

It's moved on since all of us were at school, but like most words, efficient still has the same meaning. And like so many words it also gets used inaccurately, imprecisely and for the purposes of promotional bs.


NT

On Tuesday, 16 June 2020 20:56:19 UTC+1, Robin wrote:
On 16/06/2020 17:59, tabbypurr wrote:
On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for any waste energy to go. Thus energy input & energy output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in the traditional
definition "the ratio of the useful work performed by a machine to the
total energy expended". On that it's entirely reasonable to consider
how a radiator in a CH system affects the ratio of the energy released
where it's wanted to the total energy expended (i.e. including all the
energy released where it's not - e.g. in the boiler, pump, and pipes
under suspended floors).

Looking at it another way, I'd consider a radiator which took water in
at 70 degrees and passed it out at 65 degrees to be less efficient than
one which passes it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is that I was
trying to stop the post growing even longer. Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good thing to
have at least the option of warming the room faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.

NT: useful energy out over energy in is the definition.

With a wet radiator there are only 2 places energy can go: into the room or out the outlet pipe. In neither case does the rad lose any energy, hence efficiency is 100%.


The inclusion of "useful" was good. But you then :

a. ignore the fact that not all the energy leaving through the output
pipe is "useful" if the rest of the system has losses (i.e. heat lost
where it's not wanted); and

It's not being ignored, we know there are losses in the boiler & in a minority of cases the pipework running where heat is not wanted. Those inefficiencies occur in those devices, not in the radiator.

It's also not news that often one component's operation affects efficiency elsewhere in a system.


b. assume that all energy released into the room is equally useful when
in many cases it's not because the idea is to make people in the room
/feel/ comfortable.

Measuring (b) is complicated and I don't pretend to understand all the
components. But a simple example is that a pure convector in a room
with a high, cold ceiling is not the best source. And I don't need to
as clever people have written BS 7726 (Ergonomics of the thermal
environment €” Instruments for measuring physical quantities) which
defines an "operative temperature". So my definitions of the efficiency
of a radiator would focus on how much it increases the operative
temperature for (a) a given (net) energy released by the radiator and
(b) the corresponding (gross) energy the system has to provide.

I stumbled across this subject some years ago when looking for evidence
about the claims for tall radiators - which do seem to have benefits for
a given area.

It's sometimes relevant, in a huge domed hall, heat in the dome could be regarded as waste. But in your average domestic semi it's not normally an issue and does not affect system efficiency. It never affects radiator efficiency.


NT

On 16/06/2020 22:25:34, wrote:
On Tuesday, 16 June 2020 20:08:04 UTC+1, Fredxx wrote:
On 16/06/2020 17:59:37, tabbypurr wrote:
On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for any waste energy to go. Thus energy input & energy output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in the traditional
definition "the ratio of the useful work performed by a machine to the
total energy expended". On that it's entirely reasonable to consider
how a radiator in a CH system affects the ratio of the energy released
where it's wanted to the total energy expended (i.e. including all the
energy released where it's not - e.g. in the boiler, pump, and pipes
under suspended floors).

Looking at it another way, I'd consider a radiator which took water in
at 70 degrees and passed it out at 65 degrees to be less efficient than
one which passes it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is that I was
trying to stop the post growing even longer. Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good thing to
have at least the option of warming the room faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.

NT: useful energy out over energy in is the definition.

With a wet radiator there are only 2 places energy can go: into the room or out the outlet pipe. In neither case does the rad lose any energy, hence efficiency is 100%.

Energy efficiency is always going to be 100% for a radiator.

Efficiency has several meanings. This might assist:
https://en.wikipedia.org/wiki/Effici...disambiguation)

only one of which applies here, and that is:
Energy efficiency (physics), the ratio of power consumed to useful power output


For the avoidance of difficulty in comprehending English, this may also
assist:
https://www.oxfordlearnersdictionari...lish/efficient

Adjective: doing something in a good, careful and complete way with no
waste of time, money or energy

a usage of the word that applies primarily to a person's actions. 'with no waste of energy' certainly applies to radiators. Good & careful certainly have nothing to do with radiator efficiency.


It doesn't just have to be time, money or energy. It could be weight or
area in respect of a radiator.

sorry but no. The definition of efficiency in physics & engineering is useful energy output divided by input. That's just what efficiency is.


A radiator may be more efficient
radiating heat if the water is at a higher temperature.

Radiation from a radiator versus convection is irrelevant to its efficiency. That is more relevant to filament lamps.


Some further examples
2) efficient heating equipment
3) more efficient use of energy
4) fuel-efficient cars (= that do not use much fuel)
10) efficient in something - Modern water boilers are highly efficient
in fuel use.

those are of course the efficiency that we are discussing, useful energy output over input.


5) We offer a fast, friendly and efficient service.
6) This is simply the most efficient way to do it.
7) We must meet members' needs in the most efficient and effective ways
possible.

Generally waffly bs uses of the word

Which has now become common usage. I suspect you still think kinky means
fashionable and gay means happy.

1) a highly efficient worker
9) efficient at something - These magnificent animals were remarkably
efficient at survival.
11) efficient in doing something - He was ruthlessly efficient in
acquiring estates.

again useful output over input, though used with rather less precision


8) efficient at something As we get older, our bodies become less
efficient at burning up calories.

not even true. Old bodies do become less efficient at doing work this calories, but not less efficient at burning them.

Old bodies also become more senile and resistant to change too. They use
the English language less efficiently and still think they are kinky and
gay.

There may be occasions where you might swap the word for effectiveness,
in many instances they are synonyms.

Perhaps English has moved on since you were at school?

It's moved on since all of us were at school, but like most words, efficient still has the same meaning. And like so many words it also gets used inaccurately, imprecisely and for the purposes of promotional bs.

No, many words like 'efficient' have changed. Do you really still think
kinky means fashionable and gay means happy.

On 16/06/2020 22:33:04, wrote:
On Tuesday, 16 June 2020 20:56:19 UTC+1, Robin wrote:
On 16/06/2020 17:59, tabbypurr wrote:
On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for
any waste energy to go. Thus energy input & energy
output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in
the traditional definition "the ratio of the useful
work performed by a machine to the total energy
expended". On that it's entirely reasonable to
consider how a radiator in a CH system affects the
ratio of the energy released where it's wanted to the
total energy expended (i.e. including all the energy
released where it's not - e.g. in the boiler, pump, and
pipes under suspended floors).

Looking at it another way, I'd consider a radiator
which took water in at 70 degrees and passed it out at
65 degrees to be less efficient than one which passes
it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is
that I was trying to stop the post growing even longer.
Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good
thing to have at least the option of warming the room
faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.

NT: useful energy out over energy in is the definition.

With a wet radiator there are only 2 places energy can go: into
the room or out the outlet pipe. In neither case does the rad
lose any energy, hence efficiency is 100%.


The inclusion of "useful" was good. But you then :

a. ignore the fact that not all the energy leaving through the
output pipe is "useful" if the rest of the system has losses (i.e.
heat lost where it's not wanted); and

It's not being ignored, we know there are losses in the boiler & in a
minority of cases the pipework running where heat is not wanted.
Those inefficiencies occur in those devices, not in the radiator.

It's also not news that often one component's operation affects
efficiency elsewhere in a system.


b. assume that all energy released into the room is equally useful
when in many cases it's not because the idea is to make people in
the room /feel/ comfortable.

Measuring (b) is complicated and I don't pretend to understand all
the components. But a simple example is that a pure convector in a
room with a high, cold ceiling is not the best source. And I don't
need to as clever people have written BS 7726 (Ergonomics of the
thermal environment €” Instruments for measuring physical
quantities) which defines an "operative temperature". So my
definitions of the efficiency of a radiator would focus on how much
it increases the operative temperature for (a) a given (net) energy
released by the radiator and (b) the corresponding (gross) energy
the system has to provide.

I stumbled across this subject some years ago when looking for
evidence about the claims for tall radiators - which do seem to
have benefits for a given area.

It's sometimes relevant, in a huge domed hall, heat in the dome could
be regarded as waste. But in your average domestic semi it's not
normally an issue and does not affect system efficiency. It never
affects radiator efficiency.

You're very much on your own when it comes to your definition of
radiator efficiency. This should help give you an indication of your
losing argument:
https://lmgtfy.com/?q=efficiency+of+a+radiator&s=l

The application of efficiency to a radiator isn't just heat out / heat
in. Best get used to it or be forever stuck in the past and viewed as
senile.

In article ,
wrote:
On Tuesday, 16 June 2020 18:47:11 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
Nothing is ever 100% efficient.

incorrect. Another example is an electric convector heater.

Not so either. A standard convector heater element produces light,
although likely outside the visible spectrum.

Don't think I've ever seen an oil filled radiator style heater that
emits light. As for bare element ones, some do some don't.

If it isn't visible light, you won't see it.

But it's the case that simply nothing is 100% efficient. May come very
close, though.

--
*I'll try being nicer if you'll try being smarter

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

On 15/06/2020 22:30, Robin wrote:
On 15/06/2020 21:55, wrote:
On Monday, 15 June 2020 21:11:07 UTC+1, PeterCÂ* wrote:
On Mon, 15 Jun 2020 14:42:15 +0100, Dave Plowman (News) wrote:

You'd have to state what you mean by efficiency. In the 'scientific'
meaning that would be energy in versus useful energy out. And since the
only things they do is produce heat, they are very close to 100%
efficient.

Yes - there are two ways of looking at this:
the energy in is all that in the water above ambient temperature so,
on that
basis the efficiency is low.

That would be true if all water out of the rad were at room temp. It
isn't, so the rad's energy input = flow rate x (inlet temp rise -
outlet temp rise) x SHC of water.

the 'real world' efficiency is 100% simply because the energy out is
governed by the radiator itself and the ambient conditions, i.e. the
rad.
'takes' what it puts out.

A rad is 100% efficient because there is nowhere for any waste energy
to go. Thus energy input & energy output are actually the same thing
for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in the traditional
definition "the ratio of the useful work performed by a machine to the
total energy expended".Â* On that it's entirely reasonable to consider
how a radiator in a CH system affects the ratio of the energy released
where it's wanted to the total energy expended (i.e. including all the
energy released where it's not - e.g. in the boiler, pump, and pipes
under suspended floors).

Looking at it another way, I'd consider a radiator which took water in
at 70 degrees and passed it out at 65 degrees to be less efficient than
one which passes it out at 55 degrees.Â* The second done is doing a much
better job at putting the energy where it's wanted.

Looked at just in those terms, that could simply be a function of the
flow rate... What is perhaps a more useful metric is the product of the
flow rate and the temperature drop - It would at least give a
correlation to power (i.e. rate of heat transfer into the room).


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Dave Plowman (News) wrote:

In article ,
wrote:
On Tuesday, 16 June 2020 18:47:11 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
Nothing is ever 100% efficient.

incorrect. Another example is an electric convector heater.

Not so either. A standard convector heater element produces light,
although likely outside the visible spectrum.

Don't think I've ever seen an oil filled radiator style heater that
emits light. As for bare element ones, some do some don't.

If it isn't visible light, you won't see it.

But it's the case that simply nothing is 100% efficient. May come very
close, though.

Isn't conversion of energy to heat free of that theoretical restriction
on efficiency?

--

Roger Hayter

On 16/06/2020 22:25, wrote:
On Tuesday, 16 June 2020 20:08:04 UTC+1, Fredxx wrote:
On 16/06/2020 17:59:37, tabbypurr wrote:
On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:
On 16/06/2020 08:55, PeterC wrote:
On Mon, 15 Jun 2020 22:30:39 +0100, Robin wrote:
On 15/06/2020 21:55, tabbypurr wrote:


A rad is 100% efficient because there is nowhere for
any waste energy to go. Thus energy input & energy
output are actually the same thing for a rad.


That's conservation of energy.

Efficiency involves the concept of usefulness - as in
the traditional definition "the ratio of the useful
work performed by a machine to the total energy
expended". On that it's entirely reasonable to
consider how a radiator in a CH system affects the
ratio of the energy released where it's wanted to the
total energy expended (i.e. including all the energy
released where it's not - e.g. in the boiler, pump, and
pipes under suspended floors).

Looking at it another way, I'd consider a radiator
which took water in at 70 degrees and passed it out at
65 degrees to be less efficient than one which passes
it out at 55 degrees. The second done is doing a much
better job at putting the energy where it's wanted.

Is that efficiency or is it effectivness?


It's a fair cop that I conflated the 2. My mitigation is
that I was trying to stop the post growing even longer.
Slightly longer 2nd attempt:

The second radiator is more effective (assuming it's a good
thing to have at least the option of warming the room
faster)

probably, though I don't know what 'second one' you refer to

and (very probably)
also more efficient

no.

in that the CH system delivers heat to the room more
efficiently.

no. You are still not grasping what radiator efficiency is.


Please state your definition.

NT: useful energy out over energy in is the definition.

With a wet radiator there are only 2 places energy can go: into
the room or out the outlet pipe. In neither case does the rad
lose any energy, hence efficiency is 100%.

Energy efficiency is always going to be 100% for a radiator.

Efficiency has several meanings. This might assist:
https://en.wikipedia.org/wiki/Effici...disambiguation)

only one of which applies here, and that is: Energy efficiency
(physics), the ratio of power consumed to useful power output


For the avoidance of difficulty in comprehending English, this may
also assist:
https://www.oxfordlearnersdictionari...lish/efficient



Adjective: doing something in a good, careful and complete way with no
waste of time, money or energy

a usage of the word that applies primarily to a person's actions.
'with no waste of energy' certainly applies to radiators. Good &
careful certainly have nothing to do with radiator efficiency.


It doesn't just have to be time, money or energy. It could be
weight or area in respect of a radiator.

sorry but no. The definition of efficiency in physics & engineering
is useful energy output divided by input. That's just what efficiency
is.

I don't buy that in this circumstance, since we have already highlighted
that in those terms its always 100% and also meaningless.

Hence one has to use the common English definition, which alludes to the
thing we do want to know, how *fast* the radiator can dissipate heat. In
other words what we are interested in is the output power, not the
proportion of energy out vs in.

A radiator may be more efficient radiating heat if the water is at
a higher temperature.

Radiation from a radiator versus convection is irrelevant to its
efficiency. That is more relevant to filament lamps.





Some further examples 2) efficient heating equipment 3) more
efficient use of energy 4) fuel-efficient cars (= that do not use
much fuel) 10) efficient in something - Modern water boilers are
highly efficient in fuel use.

those are of course the efficiency that we are discussing, useful
energy output over input.

Except we ain't...

There may be occasions where you might swap the word for
effectiveness, in many instances they are synonyms.

Perhaps English has moved on since you were at school?

It's moved on since all of us were at school, but like most words,
efficient still has the same meaning. And like so many words it also
gets used inaccurately, imprecisely and for the purposes of
promotional bs.

Good, lets all stop talking about radiator efficiency.

You can talk about overall system efficiency, or radiator power...

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 16 Jun 2020 at 22:10:25 BST, "
wrote:

On Tuesday, 16 June 2020 19:55:22 UTC+1, Dave Liquorice wrote:
On Tue, 16 Jun 2020 09:53:42 -0700 (PDT), tabbypurr wrote:

I suspect fanned rads will make a comeback some day once people realise
they can have a much smaller rad without all the fan noise of the old
ones.

s/fanned/finned/ ?

Not sure what that means, but they do tend to go together. A fan with a flat
panel works for a diy job but is not optimal design costwise for a new
product.

All you need for a fanned rad to work, take up way less space and be much
preferred is silence,

I can see how you get quiet for a reasonable amount

http://openecohomes.org/diy-fanned-radiator/

But silent?

and that's not a challenge.

For you, maybe :-)

--
Cheers, Rob

On 17/06/2020 00:36, John Rumm wrote:
snip

Good, lets all stop talking about radiator efficiency.

agreed - it's not a good label for what's involved and I shouldn't have
stuck with it

You can talk about overall system efficiency, or radiator power...


and, I suggest, something that captures the way it's not only the
/quantum/ of the power that matters but also /how/ it is transmitted.
Location is (I hope) an uncontroversial example: the Wiki covers how
radiators under windows differ are different from those on internal
walls. That's captured - and quantified - in the "efficiency factors"
in EN 15316[1]. But there is also work which shows size and shape also
matter[3]. You'll not be surprised to learn that (for any given power)
big and tall is best



[1] I don't have the up-to-date ones but were e.g. 0.97 under a window
vs 0.94 on an internal wall.

[3] eg https://iopscience.iop.org/article/1...X/415/1/012034

--
Robin
reply-to address is (intended to be) valid

On Tuesday, 16 June 2020 22:40:44 UTC+1, Fredxx wrote:
On 16/06/2020 22:25:34, tabbypurr wrote:
On Tuesday, 16 June 2020 20:08:04 UTC+1, Fredxx wrote:

5) We offer a fast, friendly and efficient service.
6) This is simply the most efficient way to do it.
7) We must meet members' needs in the most efficient and effective ways
possible.

Generally waffly bs uses of the word

Which has now become common usage. I suspect you still think kinky means
fashionable and gay means happy.

1) a highly efficient worker
9) efficient at something - These magnificent animals were remarkably
efficient at survival.
11) efficient in doing something - He was ruthlessly efficient in
acquiring estates.

again useful output over input, though used with rather less precision


8) efficient at something As we get older, our bodies become less
efficient at burning up calories.

not even true. Old bodies do become less efficient at doing work this calories, but not less efficient at burning them.

Old bodies also become more senile and resistant to change too. They use
the English language less efficiently and still think they are kinky and
gay.

There may be occasions where you might swap the word for effectiveness,
in many instances they are synonyms.

Perhaps English has moved on since you were at school?

It's moved on since all of us were at school, but like most words, efficient still has the same meaning. And like so many words it also gets used inaccurately, imprecisely and for the purposes of promotional bs.

No, many words like 'efficient' have changed. Do you really still think
kinky means fashionable and gay means happy.

Post when you've got something to say that's not based on you making silly things up.

On Tuesday, 16 June 2020 22:49:26 UTC+1, Fredxx wrote:

You're very much on your own when it comes to your definition of
radiator efficiency. This should help give you an indication of your
losing argument:
https://lmgtfy.com/?q=efficiency+of+a+radiator&s=l

The application of efficiency to a radiator isn't just heat out / heat
in. Best get used to it or be forever stuck in the past and viewed as
senile.

come back when you've got a fact to offer us.

On Wednesday, 17 June 2020 00:16:18 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Tuesday, 16 June 2020 18:47:11 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
Nothing is ever 100% efficient.

incorrect. Another example is an electric convector heater.

Not so either. A standard convector heater element produces light,
although likely outside the visible spectrum.

Don't think I've ever seen an oil filled radiator style heater that
emits light. As for bare element ones, some do some don't.

If it isn't visible light, you won't see it.

But it's the case that simply nothing is 100% efficient. May come very
close, though.

Feel free to tell us where the inefficiency is in an oil filled radiator. (I think we can assume it doesn't get so hot as to glow.)


NT

On Wednesday, 17 June 2020 00:37:00 UTC+1, John Rumm wrote:
On 16/06/2020 22:25, tabbypurr wrote:
On Tuesday, 16 June 2020 20:08:04 UTC+1, Fredxx wrote:
On 16/06/2020 17:59:37, tabbypurr wrote:
On Tuesday, 16 June 2020 17:51:25 UTC+1, Robin wrote:
On 16/06/2020 17:41, tabbypurr wrote:
On Tuesday, 16 June 2020 09:28:35 UTC+1, Robin wrote:

Adjective: doing something in a good, careful and complete way with no
waste of time, money or energy

a usage of the word that applies primarily to a person's actions.
'with no waste of energy' certainly applies to radiators. Good &
careful certainly have nothing to do with radiator efficiency.


It doesn't just have to be time, money or energy. It could be
weight or area in respect of a radiator.

sorry but no. The definition of efficiency in physics & engineering
is useful energy output divided by input. That's just what efficiency
is.

I don't buy that in this circumstance, since we have already highlighted
that in those terms its always 100%

we have

and also meaningless.

the meaning of efficiency in physics & engineering is well established. The failure of some to know it does not make it not so.


Hence one has to use the common English definition, which alludes to the
thing we do want to know, how *fast* the radiator can dissipate heat. In
other words what we are interested in is the output power, not the
proportion of energy out vs in.

We could probably all agree that what is relevant is something other than radiator efficiency. Deciding that that something else /is/ radiator efficiency is a factual error.


snip

Some further examples 2) efficient heating equipment 3) more
efficient use of energy 4) fuel-efficient cars (= that do not use
much fuel) 10) efficient in something - Modern water boilers are
highly efficient in fuel use.

those are of course the efficiency that we are discussing, useful
energy output over input.

Except we ain't...

yes it has been discussed here


There may be occasions where you might swap the word for
effectiveness, in many instances they are synonyms.

Perhaps English has moved on since you were at school?

It's moved on since all of us were at school, but like most words,
efficient still has the same meaning. And like so many words it also
gets used inaccurately, imprecisely and for the purposes of
promotional bs.

Good, lets all stop talking about radiator efficiency.

You can talk about overall system efficiency, or radiator power...

System efficiency is probably most relevant to the OP, and radiator choice can sometimes affect it.


NT

On Wednesday, 17 June 2020 04:45:08 UTC+1, RJH wrote:
On 16 Jun 2020 at 22:10:25 BST, tabbypurr wrote:
On Tuesday, 16 June 2020 19:55:22 UTC+1, Dave Liquorice wrote:
On Tue, 16 Jun 2020 09:53:42 -0700 (PDT), tabbypurr wrote:

I suspect fanned rads will make a comeback some day once people realise
they can have a much smaller rad without all the fan noise of the old
ones.

s/fanned/finned/ ?

Not sure what that means, but they do tend to go together. A fan with a flat
panel works for a diy job but is not optimal design costwise for a new
product.

All you need for a fanned rad to work, take up way less space and be much
preferred is silence,

I can see how you get quiet for a reasonable amount

http://openecohomes.org/diy-fanned-radiator/

But silent?

and that's not a challenge.

For you, maybe :-)

If an engineer isn't able to design a silent fan they had better stay out of that business.


NT

On Wednesday, 17 June 2020 10:48:02 UTC+1, Robin wrote:
On 17/06/2020 00:36, John Rumm wrote:
snip

Good, lets all stop talking about radiator efficiency.

agreed - it's not a good label for what's involved and I shouldn't have
stuck with it

You can talk about overall system efficiency, or radiator power...


and, I suggest, something that captures the way it's not only the
/quantum/ of the power that matters but also /how/ it is transmitted.
Location is (I hope) an uncontroversial example: the Wiki covers how
radiators under windows differ are different from those on internal
walls. That's captured - and quantified - in the "efficiency factors"
in EN 15316[1]. But there is also work which shows size and shape also
matter[3]. You'll not be surprised to learn that (for any given power)
big and tall is best



[1] I don't have the up-to-date ones but were e.g. 0.97 under a window
vs 0.94 on an internal wall.

[3] eg https://iopscience.iop.org/article/1...X/415/1/012034

All hot water radiators output their power almost entirely by convection.


NT

On 17/06/2020 12:50, wrote:
On Wednesday, 17 June 2020 10:48:02 UTC+1, Robin wrote:
On 17/06/2020 00:36, John Rumm wrote:
snip

Good, lets all stop talking about radiator efficiency.

agreed - it's not a good label for what's involved and I shouldn't have
stuck with it

You can talk about overall system efficiency, or radiator power...


and, I suggest, something that captures the way it's not only the
/quantum/ of the power that matters but also /how/ it is transmitted.
Location is (I hope) an uncontroversial example: the Wiki covers how
radiators under windows differ are different from those on internal
walls. That's captured - and quantified - in the "efficiency factors"
in EN 15316[1]. But there is also work which shows size and shape also
matter[3]. You'll not be surprised to learn that (for any given power)
big and tall is best



[1] I don't have the up-to-date ones but were e.g. 0.97 under a window
vs 0.94 on an internal wall.

[3] eg https://iopscience.iop.org/article/1...X/415/1/012034

All hot water radiators output their power almost entirely by convection.

Its typically about 80%/20% at a 70 degree flow rate.

Also worth considering is the effects of the adjacent wall. A radiator
will heat that by radiation, and you will get a boost to the rate of
convection from the "hot" wall.

(also counter intuitively, its common to place reflectors on outside
walls to reduce transmission through the wall - however in doing so, you
lose the convection boost you get from local heating of the wall
surface. It might save energy, but make the room actually feel less warm).


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Wed, 17 Jun 2020 13:10:21 +0100, John Rumm wrote:

All hot water radiators output their power almost entirely by convection.

Its typically about 80%/20% at a 70 degree flow rate.

Also worth considering is the effects of the adjacent wall. A radiator
will heat that by radiation, and you will get a boost to the rate of
convection from the "hot" wall.

(also counter intuitively, its common to place reflectors on outside
walls to reduce transmission through the wall - however in doing so, you
lose the convection boost you get from local heating of the wall
surface. It might save energy, but make the room actually feel less warm).

I'd prefer to save the energy. There is CWI but the heat gets through to the
cavity eventually and there'll be a bit of convection through the rock wool.
The reflector will reduce the rate of radiation from the rad as it's sending
some heat back into the rad - nett IR. There could be, I suppose, some
increase in convection due to the rad /not/ being cooled quite so much.

My new rad calls for at least 15 cm clearance from the floor so that
convection isn't impeded; I wonder how convection is affected by gap from
wall to rad.
--
Peter.
The gods will stay away
whilst religions hold sway

In article ,
wrote:
On Wednesday, 17 June 2020 00:16:18 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Tuesday, 16 June 2020 18:47:11 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
Nothing is ever 100% efficient.

incorrect. Another example is an electric convector heater.

Not so either. A standard convector heater element produces light,
although likely outside the visible spectrum.

Don't think I've ever seen an oil filled radiator style heater that
emits light. As for bare element ones, some do some don't.

If it isn't visible light, you won't see it.

But it's the case that simply nothing is 100% efficient. May come very
close, though.

Feel free to tell us where the inefficiency is in an oil filled
radiator. (I think we can assume it doesn't get so hot as to glow.)

Have it your own way. Some things are exactly 100% efficient. I take it
you work in advertising?

--
*The severity of the itch is proportional to the reach *

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

In article ,
wrote:
If an engineer isn't able to design a silent fan they had better stay
out of that business.

Would that be 100% silent? ;-)

--
*Make it idiot-proof and someone will make a better idiot.

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

On 14/06/2020 22:18, Duncan DiSaudelli wrote:
On 14/06/2020 20:33, Dave Liquorice wrote:
On Sun, 14 Jun 20 17:43:05 UTC, Duncan DiSaudelli wrote:


Excellent information; thanks for your help. I can see how to go about
doing some calculations and measurements.


If you have the ability and tools to drain down the whole
system, you could remove them, take them outside (if you
have a garden) and 'power flush' them with a hosepipe.

A black&decker workmate is ideal. Clamp the rad vertically
in the jaws and connect the hoepipe to an inlet then rock
the whole lot, workmate and rad back and forth until the
water runs clear.

In this weather leave in the sun to dry then gently bang
them onto the ground, impacting one of the corners where a
connection is to see if any flakes of rust or grey powdery
stuff comes out.

If a lot of stuff still comes out, try filling with cheap
vinegar and leaving for couple of days then hose them out
again.

On 15/06/2020 11:09, Harry Bloomfield wrote:
Dave Liquorice pretended :
They'll have less thermal output for a given water temperature. Old
systems with conventional boilers were designed such that the
radiators gave enough heat with water temps of 70+ C and a 10 C drop.

New systems with condensing boilers require the return to be about 55
C for maximmum boiler efficency. This means the flow is only 65 C and
if you have old radiators they won't push out enough heat.

Which will not matter, if the thermal efficiency of the home has been
improved - as seems likely, since the original rads were specced.

My house (1976) had single panel rads upstairs. In the two largest
bedrooms, the one where the class 2 flue blocks were (for the
baxi bermuda non-pumped back boiler) had a rad 2/3rds the size of
the room without this benefit.

The wall where the flue blocks were got so hot the rad was only
needed during extreme weather.

On 17/06/2020 14:46, Andrew wrote:
On 14/06/2020 22:18, Duncan DiSaudelli wrote:
On 14/06/2020 20:33, Dave Liquorice wrote:
On Sun, 14 Jun 20 17:43:05 UTC, Duncan DiSaudelli wrote:


Excellent information; thanks for your help. I can see how to go about
doing some calculations and measurements.


If you have the ability and tools to drain down the whole
system, you could remove them, take them outside (if you
have a garden) and 'power flush' them with a hosepipe.

A black&decker workmate is ideal. Clamp the rad vertically
in the jaws and connect the hoepipe to an inlet then rock
the whole lot, workmate and rad back and forth until the
water runs clear.

In this weather leave in the sun to dry then gently bang
them onto the ground, impacting one of the corners where a
connection is to see if any flakes of rust or grey powdery
stuff comes out.

If a lot of stuff still comes out, try filling with cheap
vinegar and leaving for couple of days then hose them out
again.
never seen so much black gunge when I did that .....

On 14/06/2020 23:58, wrote:
On Sunday, 14 June 2020 18:48:04 UTC+1, Duncan DiSaudelli wrote:
Hello

Our house has some single and double radiators, probably 1980s vintage,
fed from a conventional gas fired boiler.

Except for the fact that they might be full of rust and sludge etc., is
there anything radically different about modern designs which would make
them more efficient?

In other words, if they are still of sound construction, is there much
point in replacing them?

Might it be just as sensible to get the system (and thus the radiators)
power-flushed?

DDS

All rads are 100% efficient. It's not as if some of the heat can be lost outdoors from the rad.


NT


If mounted on an external uninsulated wall, then there must be
additional conduction losses via the section of wall
immediately behind the rad.

Isn't that why putting insulated foil-stuff behind the rad
was one of the 'energy saving' tricks that people used to do
in the late 70's and 80's ?.

On 14/06/2020 19:44, harry wrote:
On Sunday, 14 June 2020 18:48:04 UTC+1, Duncan DiSaudelli wrote:
Hello

Our house has some single and double radiators, probably 1980s vintage,
fed from a conventional gas fired boiler.

Except for the fact that they might be full of rust and sludge etc., is
there anything radically different about modern designs which would make
them more efficient?

In other words, if they are still of sound construction, is there much
point in replacing them?

Might it be just as sensible to get the system (and thus the radiators)
power-flushed?

DDS

Radiators do not have an efficiency.
To find if they are full of sludge, run your hand over them and see if there's any cold spots. (Invariably at the bottom.)
As long as they keep the place warm and aren't leaking leave them alone.

You might consider thermostatic valve.
If already fitted,make sure they're working.

that's a waste of time with a wummin in the house they just can't grab
the concept of turning a TVR down...all mine are screwed up due to her
so I retaliate by having the boiler thermostat at 17 dec C

On 17/06/2020 12:38, wrote:
On Wednesday, 17 June 2020 00:16:18 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Tuesday, 16 June 2020 18:47:11 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
Nothing is ever 100% efficient.

incorrect. Another example is an electric convector heater.

Not so either. A standard convector heater element produces light,
although likely outside the visible spectrum.

Don't think I've ever seen an oil filled radiator style heater that
emits light. As for bare element ones, some do some don't.

If it isn't visible light, you won't see it.

But it's the case that simply nothing is 100% efficient. May come very
close, though.

Feel free to tell us where the inefficiency is in an oil filled radiator. (I think we can assume it doesn't get so hot as to glow.)


NT


If it is placed close to an external uninsulated wall, then you have
a warm radiator and a cold radiator back-to-back, with an air gap
between them. The warmer you make the inner surface of that external
wall, the more heat will flow to the outer, cooler surface.

On 17/06/2020 14:54, Jim GM4DHJ ... wrote:
On 17/06/2020 14:46, Andrew wrote:
On 14/06/2020 22:18, Duncan DiSaudelli wrote:
On 14/06/2020 20:33, Dave Liquorice wrote:
On Sun, 14 Jun 20 17:43:05 UTC, Duncan DiSaudelli wrote:


Excellent information; thanks for your help. I can see how to go
about doing some calculations and measurements.


If you have the ability and tools to drain down the whole
system, you could remove them, take them outside (if you
have a garden) and 'power flush' them with a hosepipe.

A black&decker workmate is ideal. Clamp the rad vertically
in the jaws and connect the hoepipe to an inlet then rock
the whole lot, workmate and rad back and forth until the
water runs clear.

In this weather leave in the sun to dry then gently bang
them onto the ground, impacting one of the corners where a
connection is to see if any flakes of rust or grey powdery
stuff comes out.

If a lot of stuff still comes out, try filling with cheap
vinegar and leaving for couple of days then hose them out
again.
never seen so much black gunge when I did that .....

But would a man from BG with a powerflush machine get all
that gunge out ?. No easy way of telling..

PS Beware of doing this with single panel rads. When I did
the one from the small bedroom, it blew out some sort of
rubbery bung from inside the rad, so that I could see right
through from one connector to the other. I suspect this
was a baffle to force the water to flow through the rad
and not take the path of least resistance.

On 17/06/2020 14:57, Jim GM4DHJ ... wrote:
On 14/06/2020 19:44, harry wrote:
On Sunday, 14 June 2020 18:48:04 UTC+1, Duncan DiSaudelliÂ* wrote:
Hello

Our house has some single and double radiators, probably 1980s vintage,
fed from a conventional gas fired boiler.

Except for the fact that they might be full of rust and sludge etc., is
there anything radically different about modern designs which would make
them more efficient?

In other words, if they are still of sound construction, is there much
point in replacing them?

Might it be just as sensible to get the system (and thus the radiators)
power-flushed?

DDS

Radiators do not have an efficiency.
To find if they are full of sludge, run your hand over them and see if
there's any cold spots. (Invariably at the bottom.)
As long as they keep the place warm and aren't leaking leave them alone.

You might consider thermostatic valve.
If already fitted,make sure they're working.

that's a waste of time with a wummin in the house they just can't grab
the concept of turning a TVR down...all mine are screwed up due to her
so I retaliate by having the boiler thermostat at 17 dec C

That's a bit extreme for Scotland isn't it ?. Even in Sussex I would
feel cold at 17C.

On 17/06/2020 15:17, Andrew wrote:
On 17/06/2020 14:54, Jim GM4DHJ ... wrote:
On 17/06/2020 14:46, Andrew wrote:
On 14/06/2020 22:18, Duncan DiSaudelli wrote:
On 14/06/2020 20:33, Dave Liquorice wrote:
On Sun, 14 Jun 20 17:43:05 UTC, Duncan DiSaudelli wrote:


Excellent information; thanks for your help. I can see how to go
about doing some calculations and measurements.


If you have the ability and tools to drain down the whole
system, you could remove them, take them outside (if you
have a garden) and 'power flush' them with a hosepipe.

A black&decker workmate is ideal. Clamp the rad vertically
in the jaws and connect the hoepipe to an inlet then rock
the whole lot, workmate and rad back and forth until the
water runs clear.

In this weather leave in the sun to dry then gently bang
them onto the ground, impacting one of the corners where a
connection is to see if any flakes of rust or grey powdery
stuff comes out.

If a lot of stuff still comes out, try filling with cheap
vinegar and leaving for couple of days then hose them out
again.
never seen so much black gunge when I did that .....

But would a man from BG with a powerflush machine get all
that gunge out ?. No easy way of telling..

PS Beware of doing this with single panel rads. When I did
the one from the small bedroom, it blew out some sort of
rubbery bung from inside the rad, so that I could see right
through from one connector to the other. I suspect this
was* a baffle to force the water to flow through the rad
and not take the path of least resistance.


oh right...I bought an older static caravan and the bedroom rad started
to leak at the bottom...took it out and found it had probably frozen
solid due to no anti freeze being in the system.....why do replacement
radiators fit almost for width but have different wall brackets....pain
in the neck ...