Warning about cheap TVs currently on sale

In article , Brian Gaff wrote:
I personally think we should ban conferences, as they waste a heck of a lot
of power.
Brian

But isn't that compensated by the amount of hot air they generate?

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

Agamemnon wrote:

"Simon Slavin" wrote in message
...
I've been taking part in a conference on power use, and between
sessionssome of us worked out something of interest.

You will find and read stories of very cheap TVs being sold in the UK
from about a month ago. These are not old models, nor are they
broken, nor reconditioned. There's nothing wrong with them. So why
are they cheap ?

Answer: they use a hell of a lot of power. We looked up the manuals
for several models which were cheap in the local shops (standard TV
suppliers like Euronics, Comet, Dixons). All the models we found
unusually cheap were large power-users. Several other models which
hadn't been discounted weren't. We didn't conduct a statistically
sound test, just looked up various models we could find the manuals of
easily, but what we did findgave a clear pattern.

So you get your TV cheap and pay more to run it. I hope this warning
saves someone some money in the long term. Read the power-usage
figure before buying.

And if I can't have a cheep power hungry TV heating up the room then I
will have to pay more for the central hearting. Bloody environmentalist
morons. It's bad enough they had to phase out 100W light bulbs. How am I
supposed to stay warm while reading in bed? Don't these idiots ever
think. How much energy and damage to the atmosphere do those useless
florescent energy efficient light bulbs cost to manufacture compared to
cheep 100W ones. If the heat for the house doesn't come from them then
something else will have to provide it, so you are no better off
switching to them and neither is the planet.




In some situations this type of reasoning has a small element of truth.

However, jsut becasuse tv a uses more power than TV B, does not mean
that the differece between them is given off as heat. In fact that sort
of reasoning of really very poor and does not apply to electronics design.

cheers

David

"DM" wrote in message
. uk...
Agamemnon wrote:

"Simon Slavin" wrote in message
...
I've been taking part in a conference on power use, and between
sessionssome of us worked out something of interest.

You will find and read stories of very cheap TVs being sold in the UK
from about a month ago. These are not old models, nor are they
broken, nor reconditioned. There's nothing wrong with them. So why
are they cheap ?

Answer: they use a hell of a lot of power. We looked up the manuals
for several models which were cheap in the local shops (standard TV
suppliers like Euronics, Comet, Dixons). All the models we found
unusually cheap were large power-users. Several other models which
hadn't been discounted weren't. We didn't conduct a statistically
sound test, just looked up various models we could find the manuals of
easily, but what we did findgave a clear pattern.

So you get your TV cheap and pay more to run it. I hope this warning
saves someone some money in the long term. Read the power-usage
figure before buying.

And if I can't have a cheep power hungry TV heating up the room then I
will have to pay more for the central hearting. Bloody environmentalist
morons. It's bad enough they had to phase out 100W light bulbs. How am I
supposed to stay warm while reading in bed? Don't these idiots ever
think. How much energy and damage to the atmosphere do those useless
florescent energy efficient light bulbs cost to manufacture compared to
cheep 100W ones. If the heat for the house doesn't come from them then
something else will have to provide it, so you are no better off
switching to them and neither is the planet.




In some situations this type of reasoning has a small element of truth.

However, jsut becasuse tv a uses more power than TV B, does not mean that
the differece between them is given off as heat. In fact that sort of
reasoning of really very poor and does not apply to electronics design.

cheers

David


surely all the input comes out as heat somewhere (including light)?

DM wrote:


In some situations this type of reasoning has a small element of truth.

However, jsut becasuse tv a uses more power than TV B, does not mean
that the differece between them is given off as heat. In fact that sort
of reasoning of really very poor and does not apply to electronics design.

So perhaps you could tell us what else it comes out as and some idea of
what proportion doesn't come out as heat?

--

It's bad enough they had to phase out 100W light bulbs. How am I supposed
to stay warm while reading in bed? Don't these idiots ever think. How much
energy and damage to the atmosphere do those useless florescent energy
efficient light bulbs cost to manufacture compared to cheep 100W ones. If
the heat for the house doesn't come from them then something else will
have to provide it, so you are no better off switching to them and neither
is the planet.

Indeed. I haven't used central heating for years. I keep a 100 watt lamp
running in every room, and the wife, the kids and I have a stepladder each.
We climb up and warm ourselves in the heated area 1 foot below the ceiling.
My gas bills have plummeted :-)

In reality, I haven't bought a 100 watt light bulb for at least 5 years. I
have one in a seldom used light but every other light and lamp is either
fitted with halogen capsules, recessed halogens or CFL's. I've got a few 100
watt lamps in a box in the garage, should I put them on Ebay or offer them
to Daily Mail readers?

I was given a variety wattage box of Philips Genie CFLs, which I find
excellent. Some of the CFLs are horrible, but these warm up very quickly and
offer a good amount of light with a more natural colour than some of the
others. Robert Dyas currently selling all wattages at 5 for £2.50.

In article ,
DM wrote:

However, jsut becasuse tv a uses more power than TV B, does not mean
that the differece between them is given off as heat.

Yes it does. All the energy used by a television ends up as heat.
Light reflects around a bit and is then absorbed, heating up whatever
absorbs it. The same goes for sound.

In fact that sort
of reasoning of really very poor and does not apply to electronics design.

So what's your theory? Where do you think the power goes?

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

Bob Latham wrote:

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.

It's significant, for example see
http://groups.google.co.uk/group/uk....n&dmode=source
and many other threads in the archives of uk.d-i-y.

NB the diagram I referred to in the above-mentioned post has moved to
http://www.maxwell.myzen.co.uk/uk.d-i-y/AM3_fig2.6.gif

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.

All boilers with any pretence of high efficiency use fanned flues to
control the aspiration rate and keep excess air flow to a minimum.
Otherwise the energy lost in heating atmospheric nitrogen which is just
discharged through the flue would detract significantly from the
efficiency. Also a fan can stop when the boiler is not firing, reducing
air flow and thus heat lost from the circulating water to the flue by
reverse action of the heat exchanger.

--
Andy

"Bob Latham" wrote in message
...
In article ,
Dave Plowman (News) wrote:
In article , Brian Gaff
wrote:
Many modern boilers have very cool flues I notice. Thus one assumes
they must capture the heat somehow internally.

Commonly called condensing boilers. Identifiable by the plume of water
vapour from the flue on cold days. For others, obviously. ;-)

From what I understand and I'm not an expert, there is a problem with
condensing boilers though. It seems that they use two heat exchangers, the
second of which works in the normal way. The first one however is used to
heat the returning (coldest) water before it enters the main part of the
boiler.

The condensing action recovers heat (latent) that is used to change a
liquid into a gas and hence returns *mostly* steam into water. The problem
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.


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.


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.


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.


Bob.

"Dave Plowman (News)" wrote in message
...
In article ,
Bob Latham wrote:
In article ,
Dave Plowman (News) wrote:
In article , Brian Gaff
wrote:
Many modern boilers have very cool flues I notice. Thus one assumes
they must capture the heat somehow internally.

Commonly called condensing boilers. Identifiable by the plume of water
vapour from the flue on cold days. For others, obviously. ;-)

From what I understand and I'm not an expert, there is a problem with
condensing boilers though. It seems that they use two heat exchangers,
the second of which works in the normal way. The first one however is
used to heat the returning (coldest) water before it enters the main
part of the boiler.

Older designs - which were actually modifications from non condensing -
could but newer ones have a purpose built heat exchanger. Although the
principle is the same.

The condensing action recovers heat (latent) that is used to change a
liquid into a gas and hence returns *mostly* steam into water. The
problem 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.

A decent modern boiler will modulate the flame and pump speed to maintain
the optimum.

Right then, that would explain why my new condensing boiler is leaving the
house colder than its predecessor. Presumably by turning up the radiators
and the thermostat to compensate for this I am making the boiler less
efficient than the one it replace. Totally useless.

With mine this means slightly slower warm up times compared
to the old non condensing boiler. Although I could over-ride this if
needed to get faster warm up by allowing the boiler to go into non
condensing mode.

Is that automatic?


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.

Yes. If the system was undersized so the boiler can rarely get into
condensing mode this is so. But most were designed to cope with
temperatures well below the winter norm so can operate in condensing mode

That's what they claim, but not the reality. But then again the last cold
spell was back in the early 90s.

for most of the time. Obviously changing otherwise ok rads for larger ones
is expensive - so you'd need to work out if the investment was worth it in
fuel savings. I did and it wasn't.

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.

Here somewhere over 20% in gas usage. Of course the rise in gas prices
means I'm actually paying more than this time last year - I installed the
new boiler last spring. The old boiler was a balanced flue type with pilot
light mounted internally where the waste heat wasn't wasted - at least in
the winter. With up to date controls - programmable thermostat for the
main living area and TRVs elsewhere. The new boiler is weather
compensated. But the hot water remains as was - a storage system.

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.

Fan assisted flues came in long before condensing boilers. They allow a
longer flue than the older balanced flue terminals.

wrote in message
...

And if I can't have a cheep power hungry TV heating up the room then I
will
have to pay more for the central hearting.

Only when the weather is cold! On a hot summer night, you would have
to put a fan on or turn the air conditioning system on to cool down
this unwanted heat generated.

On a hot summer night I would be going out.