BBC promoting snake oil

I'm shocked to see Auvache's BBC promoting snake oil products that
purport to save energy.

They fitted a device that saves energy by "reducing the voltage in your
house from 240V to 220V."

F.F.S.

 

I saw that, it was a simple transformer that turned the house's
electrical system into a 220V one.

How does that not work?

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Nearly everything requires a certain amount of watts to work. Watts =
volts x amps. If you reduce the volts, then the amps increase - this
applies to power supplies, low energy light bulbs etc. For other stuff
with heating elements - kettles/toasters etc. it just takes longer to do
the same thing, ultimately using the same amount of electricity. The
only thing it saves is on ordinary light bulbs, which glow more dimly.

 

Because a 100W device will just draw more current to compensate for the
lower voltage. 100W is 100W is 100W.

 

Nice. I could've saved all that typing.

 

Not that simplistic.

Things that move will be the only ones liable to draw more current.

Things that work by getting hot like kettles and toasters will, as others
have stated, get less hot and draw less current but for longer.

Things with clever power supplies that sample the mains on a needs basis
like teleboxes and computers will perform exactly as they have performed
before but in order to do so will draw their current for longer.

 

Ultimately, the energy consumed will be the same, even if the rate at
which the energy consumed is lower.

A minute and a half to boil a kettle at 2KW or three minutes at 1KW, the
amount of gas, oil or coal burnt to produce the juice is the same either
way.

 

This is true for heating elements but not true for hot wire type light
bulbs. Folks won't have the light on for an extra hour just to make up
for what was missed by it glowing fewer brightly. So, in the case of
those, there is a potential energy saving.

The basic premise though that reducing your house voltage from 240[1] to
220 as a primary means of saving energy is utter fucking bollox is still
true.


[240] I am no expert on high voltage transmission and stuff but I was
always told the best you could expect as a domestic user was 240V at your
nearest transformer and somewhat less than that from your socket. The
value of somewhat depending, as ever, on how far away from the source you
were. Nominal I think is the official term.

 

No, but they might buy a higher-wattage bulb to make up for the loss of
brightness.

 

Which is not good because it will mean more tax for the gummint to use to
subsidise the decommissioning costs of nuclear reactors and if people
think it is going to be cheaper then they will do it sooner while the
gummint still has some money left for frittering on pointless gestures and
then all our grandchildren will all die because of burning oil.

 

Which is probably a moot point nowadays, as standard filament bulbs can
no longer be purchased. Apparently.

Quite.

 

I was rummaging in the crates in garage last weekend, looking for
something or other, and came across a pack of six 100W light bulbs.

Which was nice.

 

Not quite true, lower wattage ones are still available.


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I thought it was all of them. But I appear to have been corrected.

 

In some applications they're no longer available, but lower-wattage
ones, and odd sizes, are still to be found on supermarket shelves.

 

IRL it's probably less efficient at 1KW than at 2KW, as there's more time
for heat loss to the environment, so you'll use more energy.

 

Have they invented the ideal lossless transformer?

http://www.tpub.com/content/doe/h1011v4/css/h1011v4_56.htm

 

Except that the transformer gadget will itself not be 100% efficient,
likely wasting 5 to 10% depending on loading.

 

steve auvache formulated on Thursday :

Again not true....

An ordinary lamp bulb designed for 240v works at it most efficient for
producing light, rather than heat, at its stated voltage. Reduce the
voltage and more lights may then need to be turned on to produce the
same lighting level.

 

Nothing to do with transformer but to do with sampling. Some devices
doesn't need 240v 24/7 but can manage on small samples and a store. Reduce
the supply voltage by 10% and the device will simply sample for longer to
make up the shortfall in raw volts. The overall power it uses will change
not a jot. Thus taking even more credibility away from those ignorant many
who think that knocking the mains down 10% will of itself reduce energy
consumption.