Warning about cheap TVs currently on sale

In article ,
DM wrote:

Heat is the energy corresponding to temperature.

temperature alone does not equal energy

No, but I didn't say that.

Every eletronic element within a TV has mass, all mass when heated up
stores that heat as potential energy relative to teh surrounding
environment.

Stored as heat.

The heat is stored, and not dissipated efficeintly.

Unless the TV gets hotter and hotter, it cannot go on storing heat.
So after a while the heat radiated/conducted/convected from the TV
while equal the heat input.

And when it's switched off, it will cool down again to room
temperature, at which point it will have lost all the heat.

The same is true of a radiator.

You belive light output all contributes to heat, but again this is
incorrect- everything would appear black if this was true. - evidently
that is mot so.

Turn on a light for a few seconds. Turn it off again. All is black!
All the light energy becomes heat within microseconds. If energy could
be stored as light, you'd just have to turn the light on briefly and
your room would stay light all nighjt.

Not all light or sound energy will heat up your room - think about it in
a little more depth.

Your condescending comments would be more effective if you weren't
completely wrong.

All the light and sound energy *will* heat up your room, except that
which escapes (light out of the window, noise annoying the neighours).

A hoover converts electrical energy into movement- yes some of this ends
up as heat, but not all - there are some not incosiderabel losses along
eth way.

No, all of it ends up as heat. The "losses" are losses to heat.

sound energy is not converted efficeintly to heat- agian there is
considerable movement along the way.

You keep using this word "efficiently'. What do you mean? Where do
you think the energy *does* end up? In a big noise bouncing around
the universe?

an electrical fan will not generate heat effciently

It will generate exactly as much heat as it consumes electricity. Of
course, being a fan it may well transport some of that heat to other
places.

... apply some critical thinking and you sooen see that there aremany
transition sform one form of energy to another- and they do not all
fundamentally end up with 100% of the input increasing teh temperature
of eth surrpounding environment.

This is just wrong. It's not a question of critical thinking: you
just don't know the facts.

If you want to pursue this argument, I suggest you tell us what you
think the energy ends up as, rather than just talking about
"transition forms" and "efficiency". Just give us one form of energy
that is left one second after being emitted from a television, that
isn't heat.

-- Richard
--
Please remember to mention me / in tapes you leave behind.

(Richard Tobin) wrote:

If you want to pursue this argument,

Lost cause I think, and if you think this guy is bad our education system
is currently turning out more like him by the million.

I am reminded of some study exercise on the education part of the BBC web
site....

BBC: What is 2 + 2?
Me: 3
BBC: Bad luck, the answer is not 3, try again.


What kind of response is "Bad luck" to someone who doesn't know what 2+2
is?

I left that site with huge self esteem, I knew I was smarter than Einstein,
just really really unlucky.......

Perhaps our poster is similarly deluded.

--

DM wrote:
Richard Tobin wrote:
In article ,
DM wrote:

I'm not disputing that. I just want to dispel this idea that some
energy, such as sound, doesn't end up as heat.

What are you defining as heat here?

Heat is the energy corresponding to temperature.

temperature alone does not equal energy

Agreed.

Let us go back to the original case of tv efficiency.

Take a TV that comsumes 100W and take a 1 ohm resistor with 10V and
10 Amps running through it.
Put them bothe in a 1m cube, and measure the temperature increase.
Do you believe that they will both be exactly the same.?

Ignoring the fact that the TV and resistor will have different heat
capacities, yes. Energy is conserved. A TV doesn't have any way to

no argument here on conservation of energy- thats pretty fundamental

ok... we will come back to this

store appreciable amounts of non-heat energy, so it has to end up as
heat. A 100W TV produces 100J of heat each second, just like the

Every eletronic element within a TV has mass, all mass when heated up
stores that heat as potential energy relative to teh surrounding
environment. The heat is stored, and not dissipated efficeintly.

No.

All the components in the TV will have a heat capacity - that is
dictated by the specific heat capacity of the material in question, and
the amount you have of it.

So for a simple carbon resistor that will be around 700J /kg/K if you
ignore its leads for the moment.

As a current flows through the resister it will get hotter, so as you
say its potential energy will increase and it will be storing a small
amount of energy as heat. However the rate of heat loss to its
surroundings will also increase since this is dictated by the
temperature differential to its surroundings. If the current remains
constant, the the power being developed in the resister will also remain
constant and the temperature will continue to rise. After a time one of
two things could happen. The resistor could over heat and fail open
circuit, or more likely, equilibrium will be reached. At this point the
rate of heat loss to the surroundings will exactly match the power input
to it. When you turn the set off, the resister will then lose its stored
heat to the surroundings as well.

Hence ultimately all the energy dissipated by the resistor is lost as heat.

You belive light output all contributes to heat, but again this is
incorrect- everything would appear black if this was true. - evidently
that is mot so.

How do you come to that conclusion?

When light strikes an object, some of it is reflected, and some will be
absorbed (and this will happen no matter how reflective the surface,
since no surface it perfectly reflective). The proportion of the light
which is absorbed will result in a rise in temperature of the object
absorbing it. Of the reflected light, it will also in turn hit an
object where some will be absorbed and some reflected. This will
continue to happen until all the light has been absorbed. Now in your
closed box, the light will bounce around for few nano seconds - but
ultimately it will all be absorbed - how many reflections are
sustainable before absorption of all the photons will depend on the
reflectivity or the surfaces and the amount of light in the first place.

So unless the light keeps on being generated, it gets dark very quickly.
Assuming the light stays on, then steady state is also reached very
quickly, with all the light being generated, being reabsorbed within a
few reflections, but the reflections prevent everything appearing black.

Not all light or sound energy will heat up your room - think about it in
a little more depth.

Not so, see above.

(we can do this again at the quantum level if you want - but the answer
is still the same)

resistor.

Thre are very few household electrical applicances for which this is
not true. A battery charger is one, of course, because it
(temporarily) converts electrical energy into chemical potential
energy by causing a reaction in the cell. I can't immediately think
of any others.


A hoover converts electrical energy into movement- yes some of this ends
up as heat, but not all - there are some not incosiderabel losses along
eth way.

So the motor pushes some air about, and drives the brush bar. Of the
power going in, approx half to a third will be converted directly to
heat in the motor windings etc, the rest will end up temporarily stored
as kinetic energy of the moving parts and air flow. Now think what
happens when you switch the unit off? The air does not keep circulating
for long, and the brush bar stops spinning. Hence all of its kinetic
energy has been dissipated to its surroundings. Again when operating the
laws of conservation of energy dictate that the rate of energy input
must match that being dissipated once steady state is reached. (any
stored heat will of course also be released to the surroundings).

sound energy is not converted efficeintly to heat- agian there is
considerable movement along the way.

And that movement, left to the effects of friction turns into?

an electrical fan will not generate heat effciently

Alas, ultimately that is all it does generate.

... apply some critical thinking and you sooen see that there aremany
transition sform one form of energy to another- and they do not all
fundamentally end up with 100% of the input increasing teh temperature
of eth surrpounding environment.

It seems you would like to have the second law of thermodynamics
revoked. Alas that is not going to happen. Energy will be conserved, but
entropy will rise with each change of state.

Yes there are cases where energy can be put into a system and it can be
stored - however the storage capacity of any system is not infinite - if
you keep adding more energy it has to come out again (lets ignore fusion
reactions for the moment).




--
Cheers,

John.

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|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"DM" wrote in message
...
Richard Tobin wrote:
In article ,
A hoover converts electrical energy into movement- yes some of this ends
up as heat, but not all - there are some not incosiderabel losses along
eth way.

sound energy is not converted efficeintly to heat- agian there is
considerable movement along the way.

an electrical fan will not generate heat effciently

... apply some critical thinking and you sooen see that there aremany
transition sform one form of energy to another- and they do not all
fundamentally end up with 100% of the input increasing teh temperature of
eth surrpounding environment.

This is really tragic. What sort of an educational system do we have in this
country?

Bill

That would explain why the new condensing boiler that was installed in
my house is more noisy than the old boiler it replaced and provides less
heat than it's predecessors while using about the same amount of gas.

Well the noise will be down to the fan - something it shares with all
modern boilers.


And not just very modern. When we moved into this house, we inherited an 8
year old Worcester Bosch combi which sounded like a jet engine. It's
installed out in a utility room, and we have no very near neighbours, but it
still irritated me. A replacement fan solved the problem completely,
lubricating the old one had provided only a temporary fix.

Replacing the fan involves removing part of the flue. The original installer
here obviously had a reading problem. Where the instructions had said "Use
screws to fix the flue liner and seal with silicone sealant" the installer
had read "Don't bother with screws, squirt several tubes of silicone sealant
around everything and bugger off." That added about an hour on to my job!

Richard Tobin wrote:
In article ,
DM wrote:

Heat is the energy corresponding to temperature.

temperature alone does not equal energy

No, but I didn't say that.

Every eletronic element within a TV has mass, all mass when heated up
stores that heat as potential energy relative to teh surrounding
environment.

Stored as heat

The heat is stored, and not dissipated efficeintly.

Unless the TV gets hotter and hotter, it cannot go on storing heat.
So after a while the heat radiated/conducted/convected from the TV
while equal the heat input.

And when it's switched off, it will cool down again to room
temperature, at which point it will have lost all the heat.

The same is true of a radiator.

You belive light output all contributes to heat, but again this is
incorrect- everything would appear black if this was true. - evidently
that is mot so.

Turn on a light for a few seconds. Turn it off again. All is black!
All the light energy becomes heat within microseconds. If energy could
be stored as light, you'd just have to turn the light on briefly and
your room would stay light all nighjt.

Not all light or sound energy will heat up your room - think about it in
a little more depth.

Your condescending comments would be more effective if you weren't
completely wrong.

All the light and sound energy *will* heat up your room, except that
which escapes (light out of the window, noise annoying the neighours).

A hoover converts electrical energy into movement- yes some of this ends
up as heat, but not all - there are some not incosiderabel losses along
eth way.

No, all of it ends up as heat. The "losses" are losses to heat.

sound energy is not converted efficeintly to heat- agian there is
considerable movement along the way.

You keep using this word "efficiently'. What do you mean? Where do
you think the energy *does* end up? In a big noise bouncing around
the universe?

an electrical fan will not generate heat effciently

It will generate exactly as much heat as it consumes electricity. Of
course, being a fan it may well transport some of that heat to other
places.

... apply some critical thinking and you sooen see that there aremany
transition sform one form of energy to another- and they do not all
fundamentally end up with 100% of the input increasing teh temperature
of eth surrpounding environment.

This is just wrong. It's not a question of critical thinking: you
just don't know the facts.

If you want to pursue this argument, I suggest you tell us what you
think the energy ends up as, rather than just talking about
"transition forms" and "efficiency". Just give us one form of energy
that is left one second after being emitted from a television, that
isn't heat.

-- Richard

Richard you continue to miss the essential point here.

We are talkiing about the rate at which the energy supplied increases
the temperature of the room.

Not all items that use electrical energy will transfer that energy to
heat at the same rate, hence they are less efficient as a source of heat
to a room.

It is not a question as to whether all the energy eventaully ends up as
heat- but how long it takes to do so. COnsider the anythung that has
went before and introduce that essentail time element, and then you may
reconsider your position if you want- or you can stick your head in the
sand.

John Rumm wrote:
DM wrote:
Richard Tobin wrote:
In article ,
DM wrote:

I'm not disputing that. I just want to dispel this idea that some
energy, such as sound, doesn't end up as heat.

What are you defining as heat here?

Heat is the energy corresponding to temperature.

temperature alone does not equal energy

Agreed.

Let us go back to the original case of tv efficiency.

Take a TV that comsumes 100W and take a 1 ohm resistor with 10V and
10 Amps running through it.
Put them bothe in a 1m cube, and measure the temperature increase.
Do you believe that they will both be exactly the same.?

Ignoring the fact that the TV and resistor will have different heat
capacities, yes. Energy is conserved. A TV doesn't have any way to

no argument here on conservation of energy- thats pretty fundamental

ok... we will come back to this

store appreciable amounts of non-heat energy, so it has to end up as
heat. A 100W TV produces 100J of heat each second, just like the

Every eletronic element within a TV has mass, all mass when heated up
stores that heat as potential energy relative to teh surrounding
environment. The heat is stored, and not dissipated efficeintly.

No.

All the components in the TV will have a heat capacity - that is
dictated by the specific heat capacity of the material in question, and
the amount you have of it.

So for a simple carbon resistor that will be around 700J /kg/K if you
ignore its leads for the moment.

As a current flows through the resister it will get hotter, so as you
say its potential energy will increase and it will be storing a small
amount of energy as heat. However the rate of heat loss to its
surroundings will also increase since this is dictated by the
temperature differential to its surroundings. If the current remains
constant, the the power being developed in the resister will also remain
constant and the temperature will continue to rise. After a time one of
two things could happen. The resistor could over heat and fail open
circuit, or more likely, equilibrium will be reached. At this point the
rate of heat loss to the surroundings will exactly match the power input
to it. When you turn the set off, the resister will then lose its stored
heat to the surroundings as well.

Hence ultimately all the energy dissipated by the resistor is lost as heat.

Ultimately yes - but the issue if power and energy conversion efficeiny


You belive light output all contributes to heat, but again this is
incorrect- everything would appear black if this was true. - evidently
that is mot so.

How do you come to that conclusion?

When light strikes an object, some of it is reflected, and some will be
absorbed (and this will happen no matter how reflective the surface,
since no surface it perfectly reflective). The proportion of the light
which is absorbed will result in a rise in temperature of the object
absorbing it. Of the reflected light, it will also in turn hit an
object where some will be absorbed and some reflected. This will
continue to happen until all the light has been absorbed. Now in your
closed box, the light will bounce around for few nano seconds - but
ultimately it will all be absorbed - how many reflections are
sustainable before absorption of all the photons will depend on the
reflectivity or the surfaces and the amount of light in the first place.

So unless the light keeps on being generated, it gets dark very quickly.
Assuming the light stays on, then steady state is also reached very
quickly, with all the light being generated, being reabsorbed within a
few reflections, but the reflections prevent everything appearing black.

Again a simepl matter of time.

If it is absobed then eth ernergy transfer is 1nS saym if it is
reflected and absorbed at a later time then the energy transfer is 2ns
say. Now in case 1 the power trasfer is doubele case 2. So it is a
more efficeint case to heaqt up the matter. We are talking about the
effciency of differnet sources for heat- we can not wait indefiently



Not all light or sound energy will heat up your room - think about it
in a little more depth.

Not so, see above.

(we can do this again at the quantum level if you want - but the answer
is still the same)

resistor.

Thre are very few household electrical applicances for which this is
not true. A battery charger is one, of course, because it
(temporarily) converts electrical energy into chemical potential
energy by causing a reaction in the cell. I can't immediately think
of any others.


A hoover converts electrical energy into movement- yes some of this
ends up as heat, but not all - there are some not incosiderabel losses
along eth way.

So the motor pushes some air about, and drives the brush bar. Of the
power going in, approx half to a third will be converted directly to
heat in the motor windings etc, the rest will end up temporarily stored
as kinetic energy of the moving parts and air flow. Now think what
happens when you switch the unit off? The air does not keep circulating
for long, and the brush bar stops spinning. Hence all of its kinetic
energy has been dissipated to its surroundings. Again when operating the
laws of conservation of energy dictate that the rate of energy input
must match that being dissipated once steady state is reached. (any
stored heat will of course also be released to the surroundings).

sound energy is not converted efficeintly to heat- agian there is
considerable movement along the way.

And that movement, left to the effects of friction turns into?

an electrical fan will not generate heat effciently

Alas, ultimately that is all it does generate.

... apply some critical thinking and you sooen see that there aremany
transition sform one form of energy to another- and they do not all
fundamentally end up with 100% of the input increasing teh temperature
of eth surrpounding environment.

It seems you would like to have the second law of thermodynamics
revoked. Alas that is not going to happen. Energy will be conserved, but
entropy will rise with each change of state.

Yes there are cases where energy can be put into a system and it can be
stored - however the storage capacity of any system is not infinite - if
you keep adding more energy it has to come out again (lets ignore fusion
reactions for the moment).

In article , Dm wrote:
Not all items that use electrical energy will transfer that energy to
heat at the same rate, hence they are less efficient as a source of heat
to a room.

It is not a question as to whether all the energy eventaully ends up as
heat- but how long it takes to do so. COnsider the anythung that has
went before and introduce that essentail time element, and then you may
reconsider your position if you want- or you can stick your head in the
sand.

If a television set (for example) "takes longer" to turn electrical energy
into heat than some other appliance (a heater perhaps), what happens to the
energy in the TV set to delay it before it emerges as heat? Where is it
stored, and in what form?

After the delay, when the heat eventually does emerge and everything
stabilises, if the television set is consuming electrical energy at a rate
of 100W, at what rate will heat energy be emerging from it?

Rod.
--
Virtual Access V6.3 free usenet/email software from
http://sourceforge.net/projects/virtual-access/

Roderick Stewart wrote:
In article , Dm wrote:
Not all items that use electrical energy will transfer that energy to
heat at the same rate, hence they are less efficient as a source of heat
to a room.

It is not a question as to whether all the energy eventaully ends up as
heat- but how long it takes to do so. COnsider the anythung that has
went before and introduce that essentail time element, and then you may
reconsider your position if you want- or you can stick your head in the
sand.

If a television set (for example) "takes longer" to turn electrical energy
into heat than some other appliance (a heater perhaps), what happens to the
energy in the TV set to delay it before it emerges as heat? Where is it
stored, and in what form?

After the delay, when the heat eventually does emerge and everything
stabilises, if the television set is consuming electrical energy at a rate
of 100W, at what rate will heat energy be emerging from it?

Rod.

Well put Rod.

It would be good for everyone to think about this one.

THis is exactly the whole point. A TV or another electrical appliance
is designed to perform some function. During that process the
electrical energy is not immediatley converted to heat. There is some
intermediate step. Depending on what that fucntion is will depend on
the rate at which the electrical energy is converted to heat.

If it all went immediately to heat up the room then would it perform any
other useful function?

Soem people apparently beleive that

Bill Wright wrote:
"DM" wrote in message
...
Richard Tobin wrote:
In article ,
A hoover converts electrical energy into movement- yes some of this ends
up as heat, but not all - there are some not incosiderabel losses along
eth way.

sound energy is not converted efficeintly to heat- agian there is
considerable movement along the way.

an electrical fan will not generate heat effciently

... apply some critical thinking and you sooen see that there aremany
transition sform one form of energy to another- and they do not all
fundamentally end up with 100% of the input increasing teh temperature of
eth surrpounding environment.

This is really tragic. What sort of an educational system do we have in this
country?

Bill




Indeed Bill I really dispair that so many people think a TV is an
efficient way to heat up their room.
Or can fail to see that an elctrical fan will heat up a room a lot
slower than an electrical element designed specifically to radiate heat.