Warning about cheap TVs currently on sale

Bill Wright wrote:
"DM" wrote in message
...
Richard Tobin wrote:
You'll also have a lot more luck heating your room up with a 100Watt
incandecent bulb than you will with a 100W speaker.

A 100W bulb runs at 100W all the time. A speaker rated at 100W runs at
whatever power the amp provides. In this case the '100W' refers to the
maximum the speaker can handle. So the comparision is worthless.

Think of the amp as acting like a modulating dimmer switch ;-)

--
Cheers,

John.

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

Perhaps you know now you should have got an expert to specify and install
it.

It was installed by an expert.

Richard Tobin wrote:
In article ,
Bill Wright wrote:

Quite true, and in any case amplifier power ratings are generally
entirely specious. But if it did produce 100W, it would heat things
up just as much as a 100W bulb.

But in the real world a domestic 100W speaker will not be dissipating 100W,
whereas a 100W light bulb will be. Practicality and reality are what matter.

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

-- Richard

What are you defining as heat here?

Is it kinetic or potentail energy or do you want it to be both in which
case of course everything ends up that way.

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.?

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

In article ,
Agamemnon wrote:

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

Perhaps you know now you should have got an expert to specify and
install it.

It was installed by an expert.

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

--
*Women like silent men; they think they're listening.

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

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

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

Perhaps you know now you should have got an expert to specify and
install it.

It was installed by an expert.

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

You are a complete and total moron.

In article ,
Agamemnon wrote:

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

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

Perhaps you know now you should have got an expert to specify and
install it.

It was installed by an expert.

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

You are a complete and total moron.

That could be true. Makes no difference to the facts, though.

--
*Never underestimate the power of stupid people in large groups.

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

Agamemnon wrote:

though is that this only happens whilst the returning water is cold
enough. When the water warms up, the first heat exchanger is too hot to
condense the steam in the flue and the condensing action stops as does a
lot of the heat recovery.

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.

However providing less heat and using more gas would seem to be
violating some basic laws of physics. Especially as the larger HE means
less heat is being wasted.

So what are we to conclude? Either you are not accounting for something,
or you are telling us porkies.

To improve the situation, some people seem to advocate fitting over sized
radiators in every room, the idea being to get the returning water
temperature lower so as to maintain condensing action longer.

Which of course would waste the energy unnecessarily and therefore
pollute the environment more than a conventional boiler.

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.

What I would love to know is what is the real world improvement of a
condensing boiler over just a new boiler without changing the radiators.

There isn't. They are actually worse. The old boiler lasted 25 years and
provided more heart than the new condensing boiler does, and hardly made
any noise compared to the new one.

See above

Oh, and I think these boilers have to have fans in the flue because you
can no longer rely on hot air rising to remove the fumes.

Ah, that explains all the bloody noise.

You should have bought a decent boiler - even with a fan they are very
quiet.


--
Cheers,

John.

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

"John Rumm" wrote in message
et...
Agamemnon wrote:

though is that this only happens whilst the returning water is cold
enough. When the water warms up, the first heat exchanger is too hot to
condense the steam in the flue and the condensing action stops as does a
lot of the heat recovery.

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.

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

I said used about the same amount of gas.

violating some basic laws of physics. Especially as the larger HE means
less heat is being wasted.

So what are we to conclude? Either you are not accounting for something,
or you are telling us porkies.

To improve the situation, some people seem to advocate fitting over
sized
radiators in every room, the idea being to get the returning water
temperature lower so as to maintain condensing action longer.

Which of course would waste the energy unnecessarily and therefore
pollute the environment more than a conventional boiler.

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.


What I would love to know is what is the real world improvement of a
condensing boiler over just a new boiler without changing the radiators.

There isn't. They are actually worse. The old boiler lasted 25 years and
provided more heart than the new condensing boiler does, and hardly made
any noise compared to the new one.

See above

Oh, and I think these boilers have to have fans in the flue because you
can no longer rely on hot air rising to remove the fumes.

Ah, that explains all the bloody noise.

You should have bought a decent boiler - even with a fan they are very
quiet.

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

It's predecessor was made by the same company and kept the house warmer. Or
it could be the new radiator thermostats that were installed.

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.

"Dave Plowman (News)" wrote in message
...
In article ,
chunkyoldcortina wrote:
So with such a difference in price for electricity and gas these days,
are we not better off with each house having its own mini gas-fired
generator? There's a lot of scope for inefficiency before you end up
back at 11 and a half pee per kWh...

Most engines that could be used will only have a decent efficiency at a
set load. So when it starts up when you go to the loo in the middle of the
night, not too high.

No need for it. I create my own gas at that juncture.

Bill