Well, I've been testing out all sorts of electric and electronic gear to 
find out what actually uses the most power. The results are very 
surprising...

The most thirsty device I've found so far is... the kettle. It uses in 
excess of 3,000 W for the entire duration that you try to boil water 
with it. On the other hand, something like the washing machine uses a 
tiny fraction of that, even when it's on its highest spin cycle. (Uses 
only 600 W. Actually uses 700 W while it spins up, but then drops to 600.)

I haven't tested out the TV yet, but of all the stuff I have tested, it 
seems that any device that performs any kind of *heating* instantly uses 
many times more power than anything else. I emphasize: MANY TIMES more 
power. Not 20% more, not 50% more, but nearer to 1000% more! Heck, even 
the vacuum cleaner (surely a high power device) in fact uses a fraction 
of the power that the toaster does!

Can anybody suggest why this might be? I mean, huge powerful electric 
motors use a fair bit of power, but it's almost insignificant compared 
to heating devices. Why does heating things require so much power?

Also, I notice that my PC uses about 10x as much power as my laptop. 
There are two possible explanations for this:

1. My PC is (or recently was) leading edge, whereas my laptop was pretty 
much old hat even when it was purchased.

2. It's a laptop. It's designed to use less power.

PS. We have *another* Intel Core 2 Duo laptop at work. And just like the 
first one, it seems to be utterly impossible to make it heat up, no 
matter how much number chrunching I throw at it. How do they manage that?

-- 
http://blog.orphi.me.uk/

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No answer (sorry), but two questions :

- What device do you use to mesure power ? Is it expensive ?

- Have you tried to mesure the power used by electronic devices (TV, 
HiFi, etc.) when they are on standby ? I find it difficult to get a 
estimation for this, and it seems to vary greatly even among similar 
devices ?


Thibaut


> Well, I've been testing out all sorts of electric and electronic gear to 
> find out what actually uses the most power. The results are very 
> surprising...
> 
> The most thirsty device I've found so far is... the kettle. It uses in 
> excess of 3,000 W for the entire duration that you try to boil water 
> with it. On the other hand, something like the washing machine uses a 
> tiny fraction of that, even when it's on its highest spin cycle. (Uses 
> only 600 W. Actually uses 700 W while it spins up, but then drops to 600.)
> 
> I haven't tested out the TV yet, but of all the stuff I have tested, it 
> seems that any device that performs any kind of *heating* instantly uses 
> many times more power than anything else. I emphasize: MANY TIMES more 
> power. Not 20% more, not 50% more, but nearer to 1000% more! Heck, even 
> the vacuum cleaner (surely a high power device) in fact uses a fraction 
> of the power that the toaster does!
> 
> Can anybody suggest why this might be? I mean, huge powerful electric 
> motors use a fair bit of power, but it's almost insignificant compared 
> to heating devices. Why does heating things require so much power?
> 
> Also, I notice that my PC uses about 10x as much power as my laptop. 
> There are two possible explanations for this:
> 
> 1. My PC is (or recently was) leading edge, whereas my laptop was pretty 
> much old hat even when it was purchased.
> 
> 2. It's a laptop. It's designed to use less power.
> 
> PS. We have *another* Intel Core 2 Duo laptop at work. And just like the 
> first one, it seems to be utterly impossible to make it heat up, no 
> matter how much number chrunching I throw at it. How do they manage that?
>

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Orchid XP v3 wrote:
> I haven't tested out the TV yet, but of all the stuff I have tested, it 
> seems that any device that performs any kind of *heating* instantly uses 
> many times more power than anything else.

It's amazing how much potential there is in even a small amount of heat, 
isn't it?

By the way, while heating so far beats all other estimates, IIRC cooling 
requires even *more* juice for the same amount of temperature change. 
Of course, I don't know if your air conditioner will suck in as much 
heat as your kettle puts out, but AC is probably the greatest drain on 
the power grid pretty much anywhere in the world.

> Also, I notice that my PC uses about 10x as much power as my laptop. 
> There are two possible explanations for this:
> 
> 1. My PC is (or recently was) leading edge, whereas my laptop was pretty 
> much old hat even when it was purchased.
> 
> 2. It's a laptop. It's designed to use less power.

Both.

> PS. We have *another* Intel Core 2 Duo laptop at work. And just like the 
> first one, it seems to be utterly impossible to make it heat up, no 
> matter how much number chrunching I throw at it. How do they manage that?

Several ways, one of which being that it slows itself down if it gets 
too hot :)

-- 
...Ben Chambers
www.pacificwebguy.com

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On Sat, 01 Sep 2007 19:11:57 +0100, Orchid XP v3 wrote:

> I haven't tested out the TV yet, but of all the stuff I have tested, it
> seems that any device that performs any kind of *heating* instantly uses
> many times more power than anything else. I emphasize: MANY TIMES more
> power. Not 20% more, not 50% more, but nearer to 1000% more! Heck, even
> the vacuum cleaner (surely a high power device) in fact uses a fraction
> of the power that the toaster does!
> 
> Can anybody suggest why this might be? I mean, huge powerful electric
> motors use a fair bit of power, but it's almost insignificant compared
> to heating devices. Why does heating things require so much power?

Heat is generated through increased electrical resistance; in order to 
heat a heating element up, you need to push more electricity through it.

http://en.wikipedia.org/wiki/Heating_element is a good starting point.

Jim

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I think they are starting to use microwaves in
indirect heating in some high end ovens.  The
microwaves heat some sort of target element,
then pump air thru it, the oven door can be
opened without fear of microwave leakage.
It reduces cooking time, but I bet it's better
in terms of power usage too.

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Tim Attwood wrote:
> I think they are starting to use microwaves in
> indirect heating in some high end ovens.  The
> microwaves heat some sort of target element,
> then pump air thru it, the oven door can be
> opened without fear of microwave leakage.
> It reduces cooking time, but I bet it's better
> in terms of power usage too. 

There are also induction cookers which are significantly more efficient 
than traditional conduction cooktops.

http://en.wikipedia.org/wiki/Induction_cooktop

Lance.

thezone - thezone.firewave.com.au

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Orchid XP v3 wrote:
> Can anybody suggest why this might be?

It's because heat represents a huge amount of energy.

For instance, the humble calorie, the amount of energy required to raise 
a single gram of water by one degree celsius, is the same amount of 
energy required to lift that same gram of water about 387 meters in 
Earth's gravity, or accelerate it from zero to 87 meters per second.

Regards,
John

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Orchid XP v3 wrote:
> PS. We have *another* Intel Core 2 Duo laptop at work. And just like the 
> first one, it seems to be utterly impossible to make it heat up, no 
> matter how much number chrunching I throw at it. How do they manage that?

I have a 2Gig Celeron laptop (from 2003) that gets very hot when it has 
to crunch, like during a POV-Ray render.

Regards,
John

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On Sat, 01 Sep 2007 18:19:25 -0700, Tim Attwood wrote:

> I think they are starting to use microwaves in indirect heating in some
> high end ovens.  The microwaves heat some sort of target element, then
> pump air thru it, the oven door can be opened without fear of microwave
> leakage. It reduces cooking time, but I bet it's better in terms of
> power usage too.

Probably, but I'm always reminded of the phrase "there ain't no such 
thing as a free lunch" - when it comes to generating heat, physics still 
applies.  Doesn't mean things can't be more efficient than they currently 
are, though.

Jim

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Thibaut Jonckheere wrote:

> No answer (sorry), but two questions :
> 
> - What device do you use to mesure power ? Is it expensive ?

I said it in my blog, and I'll say it again here:

http://www.maplin.co.uk/search.aspx?menuno=80119&MenuName=Power%20and%20Energy%20Monitors&FromMenu=y&worldid=-6&doy=28m8



> - Have you tried to mesure the power used by electronic devices (TV, 
> HiFi, etc.) when they are on standby ? I find it difficult to get a 
> estimation for this, and it seems to vary greatly even among similar 
> devices ?

Some devices actually use 0 W when off. (A few use 0 W even when on. For 
example, the clothes iron, once it's hot.) Most things seem to use less 
than 5 W while on standby.

And yes, the TV is one thing I still haven't got round to measuring!

-- 
http://blog.orphi.me.uk/

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