Warning about cheap TVs currently on sale

"Dave Plowman (News)" wrote in message
...
In article ,

It was installed by an expert.

You obviously have a different understanding of the word from the rest of
us.

No, the installer had a different understanding of the word 'expert'.

Bill

Agamemnon wrote:

It was a decent boiler as recommended by the government and bloody
expensive.

The case for the prosecution rests M'lord.


--
Mark
Please replace invalid and invalid with gmx and net to reply.

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.

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
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
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.

-- Richard

Now my thermodynamics is a little rusty but I don't think you're correct
here.

As you say, energy cannot be destroyed but it can be converted. In a tele
you convert some of the energy to visibile light and sound. Visible light
is of the wrong wavelength to cause appreciable heating. So, for 100W in
you'll lose some in visible light and sound so you won't get your 100J of
heating. I've no idea what the efficiency of a tele is but the net heat
output will be 100J.

I look forward to being wrong. :-)

--

WildCardZero

In article ,
Bill Wright wrote:

"Dave Plowman (News)" wrote in message
...
In article ,

It was installed by an expert.

You obviously have a different understanding of the word from the rest
of us.

No, the installer had a different understanding of the word 'expert'.

Indeed. Having recently installed *myself* a 'state of the art' system
boiler - a Viessmann - and discovered just how much software adjustment is
needed in weather compensation mode to get it exactly right I could
perhaps sympathise with some installers. Although most charge quite
sufficient to cover this. The snag being it would take several visits to
get things right. However, the fuel savings do make it worthwhile.

But Agamemnon considers me a moron so he'll have to go to his 'expert'
for help.

--
*Thank you. We're all refreshed and challenged by your unique point of view

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

"WCZ" wrote in message
...
Richard Tobin wrote:
Now my thermodynamics is a little rusty

As is my boiler.

Bill

In a tele you convert some of the energy to visibile light and sound.
Visible light is of the wrong wavelength to cause appreciable heating.
So, for 100W in you'll lose some in visible light and sound so you won't
get your 100J of heating. I've no idea what the efficiency of a tele is
but the net heat output will be 100J.

From the TV, yes. But the light from the screen is absorbed by the walls
and furniture and re-radiated as heat (eventually). Ditto the sound.

Only the light and sound that escapes from the room doesn't heat it.

Incidentally, we are talking about tiny amounts of energy here. The amount
of light energy from a screen is handful of watts, and the sound energy from
the speakers is milliwatts. The vast majority of energy emitted by any TV
is in the form of heat.

SteveT

Agamemnon wrote:

However providing less heat and using more gas would seem to be

I said used about the same amount of gas.

in cost or cubic meters?

Illogical. It takes a finite amount of energy to get your room to the
desired temperature and maintain it. The boiler will be able to do
that most effectively using the lowest flow temperature it can get
away with that still reaches the goal, since this will extract the
most energy from the gas.

So it's pumping colder water around my house. No wonder the house is
colder.

You usually have a control that will allow *you* to set the flow
temperature. Regardless of where you set it, the boiler should be more
efficient than the previous one. However setting it lower *may* improve
efficiency a little more (see the chart Andy W posted a link to). The
modulation will normally be set based on the return temperature - and
will reduce the power of the boiler as the return water gets hotter
(i.e. the heating load is reducing as the house warms up). This enables
the boiler to match its output to the load rather than overshooting the
target temperature and cycling on and off all the time (which reduces
efficiency)

Note if you have automatic weather compensation then the boiler may be
able to auto adjust the flow temperature as well in response to the
outside temperature.

If you run the boiler flow temp cooler than before, it will take longer
to reach the set temperature - however your main thermostat should keep
it running until the temperature required is reached.

It's predecessor was made by the same company and kept the house warmer.

Which boiler is it?

Is it powerful enough for the house?

Is it a combi? (note that most combis can't run the rads and the hot
water at the same time - so if a succession of people take a shower then
heating can be off for the duration)

Do you have a central room thermostat? If so what type (mechanical, or
electronic, programmable or normal)

Or it could be the new radiator thermostats that were installed.

That could well have a bigger impact. How have you get them set? Where
are they positioned on the rads?

Also were all the radiators balanced (i.e. throttled to give the same or
similar temperature rise all round the house)?

Come to think of it, it did make the house warmer in the autumn than
before and I hardly had to use the boiler, but in the winter it was
freezing. It might not be producing as much heat.

Unless the boiler is significantly less powerful than the previous one,
there is no fundamental reason it should produce less heat. However it
may be the settings are not optimal for your system.

(Its worth noting that there is little fundamental difference between a
modern boiler and a modern condensing boiler - the latter has a
condensate trap and larger heat exchanger - but otherwise they are
similar. Both are stuffed full of electronics, have fanned flues,
electronic ignition etc).


--
Cheers,

John.

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

WCZ 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.

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
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
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.

-- Richard

Now my thermodynamics is a little rusty but I don't think you're correct
here.

As you say, energy cannot be destroyed but it can be converted. In a tele
you convert some of the energy to visibile light and sound. Visible light
is of the wrong wavelength to cause appreciable heating. So, for 100W in

Assuming your box is opaque and the light can't escape, then ultimately
it will be absorbed (it may bounce about a bit - but not indefinitely).
Since light at any wavelength is stream of photons of energy. When they
are absorbed they will generally result in a heating effect.

you'll lose some in visible light and sound so you won't get your 100J of
heating. I've no idea what the efficiency of a tele is but the net heat
output will be 100J.

The 100% capture of the sound energy may be more problematical; however
for the sake of the experiment you could turn the volume off ;-)

--
Cheers,

John.

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

In article ,
WCZ wrote:

As you say, energy cannot be destroyed but it can be converted. In a tele
you convert some of the energy to visibile light and sound. Visible light
is of the wrong wavelength to cause appreciable heating.

No, there is no "wrong wavelength". However much energy goes into the
light, that much comes out when the light is absorbed. Any light that
leaves the house will of course be absorbed elsewhere.

If you still think there's a wrong wavelength to cause heating, bear
in mind that visible light can be *produced* by heating a filament.
The heating of the filament causes electrons to be pushed into higher
energy levels; when they fall back a photon is emitted. The frequency
(and thus wavelength) of the emitted photon is determined by the
difference of energy levels. When that photon is absorbed by
something (the wall perhaps), it produces the same increase in energy
level of some electron in the wall. The situation is symmetrical - if
a photon of that frequency can be produced by a transition in energy
level, it can be absorbed by a similar transition.

Or perhaps you're thinking of the fact that some wavelengths are more
easily absorbed than others. This is certainly true: glass is
transparent because it doesn't absorb the photons of visible light
very well, whereas it does absorb the (more energetic) photons of
ultra-violet. But that just means that some of the light energy will
escape through the windows before it gets absorbed and turned into
heat.

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

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


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

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.

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.

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


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.

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.