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They make a flexible solar panel that
puts out about 50 Watts, open it's 54" x 32",
folded up it's about the size of a text book.
It'll run a laptop pretty easy.
There's no real problem with putting solar
panels on houses in temperate areas, (they're
waterproof), it just means you need more panels,
so it increases the cost. Cost is the big downside
of solar electric panels, it costs more than just
buying the juice in the first place. There's quite
a few places working on making it cheaper with
limited success.
Solar concentrators rely on technology that can
be much cheaper, it's just mirrors. Evacuated
solar tubes can produce scalding hot water, or
you can build simpler solar hot water heaters
DIY at very low cost. The heat can then be
directly used for heat, thus cutting out the
90+ percent loss of turning sunlight to electricity
and then turning electricity to heat. The downside
is maintenance of the anti-freeze.
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> Wait - I thought that was still science fiction? You mean people somewhere
> *actually do this* now??
The company I work for made 600 MW of solar panels in 2006 (that's the
latest figures I could find), I'm sure it's gone up lots since then. Drive
around any village around here and you're bound to see at least a few houses
or barns covered in them.
> I rather suspect not. Turn on the kettle, the toaster and the microwave
> oven at the same time (not implausible) and you're now sucking down
> double-digit kW values.
Sure, but what's the average power over a longer period of time? You can
easily calculate this from your power bill. IIRC for me it was around 300W,
and yes I have a fridge, freezer, TV, computer etc. Even fridges and
freezers are not actually on continuously.
If you assume I'll get 2 hours a day sunlight on average (this is a big
underestimate, especially as the panels generate a reduced level of power
even when it's cloudy), that means I would need 3600W of solar panels, or an
area roughly 6x6 metres. Doesn't seem that outrageous.
> Actually, I guess the *main* difference would be that if you live in the
> Sahara, you don't give a **** about electricity, but you urgently need to
> find a crapload of water real soon now...
Funny, when I was in the Sahara desert, the villages there had a perfectly
fine water supply, also ATM machines, mobile phone coverage, etc.
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>> Wait - I thought that was still science fiction? You mean people
>> somewhere *actually do this* now??
>
> The company I work for made 600 MW of solar panels in 2006 (that's the
> latest figures I could find), I'm sure it's gone up lots since then.
> Drive around any village around here and you're bound to see at least a
> few houses or barns covered in them.
Mmm, interesting. I've never seen that. (Again, presumably because I
live in England.)
>> Actually, I guess the *main* difference would be that if you live in
>> the Sahara, you don't give a **** about electricity, but you urgently
>> need to find a crapload of water real soon now...
>
> Funny, when I was in the Sahara desert, the villages there had a
> perfectly fine water supply, also ATM machines, mobile phone coverage, etc.
Heh. And here I was thinking the only thing in a desert is sand...
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Invisible schrieb:
> If you built a laptop where the entire lid was a solar panel, would it
> generate anywhere near enough power to run the laptop?
At first glance I'd say, "might be".
If you ever took to the outside with a magnifiying glass and a piece of
paper on a summer day, you probably know how much power there is in
sunlight, when concentrated. So as a first rought guesstimate, imagine a
magnifying glass the size of a laptop lid, concentrating solar energy on
something as big as a CPU die.
If that would produce as much heat as a running CPU, then we're at least
talking about the same orders of magnitude.
Upon closer inspection of the problem, this article:
http://home.howstuffworks.com/home-improvement/energy-efficiency/question418.htm
states that with cheapo solar cells, you can harvest no more than about
.045 W per square inch; the article then goes on presuming a figure of
.070 W, probably assuming the use of higher-quality cells.
With a laptop about as large as an A4 sheet of paper - about 100 square
inch - that would give you... 7 Watts. Not /quite/ the order of
magnitude you'd probably need...
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clipka wrote:
> With a laptop about as large as an A4 sheet of paper - about 100 square
> inch - that would give you... 7 Watts. Not /quite/ the order of
> magnitude you'd probably need...
Hmm. What's the TDP of a typical CPU? About 150W? Oh dear...
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Invisible schrieb:
> Then again, with that old laptop, I start wondering if you could use it
> to run a small steam engine connected to a generater. The thing gets hot
> enough! :-P
Heh, someone called my name?!
Oh boy, I've definitely been doing too much research for that locomotive
model lately, reading stuff like this for instance:
http://www.the-nerds.org/Steam-Car-Day.html
Well, at least by now I know what /some/ of the greebly stuff on a
locomotive is actually good for...
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clipka wrote:
> Invisible schrieb:
> With a laptop about as large as an A4 sheet of paper - about 100 square
> inch - that would give you... 7 Watts. Not /quite/ the order of
> magnitude you'd probably need...
That's nearly enough to power a low-power laptop.
The OLPC (one laptop per child) scheme says their laptops are limited to
use 15 Watts
http://laptop.org/en/laptop/hardware/specs.shtml
So 7 watts is nearly there - you could fit a fold-out panel on the back
of the laptop or do something cunning with mirrors / fresnel lenses to
focus more sun on the panel.
I believe my mini ITX server uses 10 - 20 W depending on load and it's a
1 Ghz machine with a fullsize hard drive but no display and it's not the
most efficient design out there.
On the other hand "my" blade centre with 12 quad core servers in it uses
1700 W which is more than 3x my house's average consumption.
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Invisible schrieb:
> Hmm, I wonder... does the human brain heat up significantly when you
> think harder?
No, because the efficient adaptive cooling system makes sure it doesn't :-P
But yes, the human brain makes for a good deal of energy consumption in
the organism. And consumption does vary, so heat output will, too.
I'm particularly slim by build, despite virtually living on sweet stuff.
An acquaintance suggested that in order to start gaining weight, I
should actually do /more/ bodily exercising (especially endurance
training; I'm admittedly quite lazy in that respect). Why? Because
endurance training is a perfect "no-brainer".
In other words: I'm probably this slim because I think too much...
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>> Hmm, I wonder... does the human brain heat up significantly when you
>> think harder?
>
> No, because the efficient adaptive cooling system makes sure it doesn't :-P
>
> But yes, the human brain makes for a good deal of energy consumption in
> the organism. And consumption does vary, so heat output will, too.
One thing a lot of people don't seem to realise is that the brain does
*other stuff* besides thinking...
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Invisible schrieb:
> (I love the way turning my PC on requires 50% more power than playing a
> 3D-intensive computer game...)
Yeah, the turn-on is always the hardest part :-P
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