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Clear Solar Panels Double As Projection Screens
Posted by
timothy
on Sat Aug 07, 2004 08:07 PM
from the multipass dept.
from the multipass dept.
EnergyEfficient writes "Metropolis Magazine has an article about a company that is producing transparent solar panels. The panels 'can generate 3.8 watts of electricity per square foot, an above-average level of efficiency.' They come in a thick version that can be used for glazing buildings. Imagine if all those glass skyscrapers could also produce power! As an interesting aside, they can also be used as screens for projection TV units."
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Wonder if they are more efficient... (Score:3, Insightful)
Re:Wonder if they are more efficient... (Score:5, Informative)
I gotta look at my 165 W sharps which are about 8sq feet and wonder at that. But my panels are not clear. Which is a plus as the also shade the roof and make that part of the house cooler. (if only they had 1/2" pipes wired under them so I could water cool them and run the warmed water into a tank).
And yes, the windows are mounted vertically. In math, that's at 90 degrees.
The ideal mounting angle is your latitude (eg the Bay Area and DC are around 37 degrees).
So these will be most efficient at Sunrise/Sunset. When the sun is at its weakest (lots of atmosphere to get through).
On the other hand, if they are good projection screens, you aim your projector at it, that causes it to generate power which you can use to plug the projector into!! Perpetual energy!!!
or something.
Bottom line:
If they work and don't cost a lot more than regular windows (such that in 10 years they save more in power costs than they cost), then great!
If every house with a decent roof exposure between 10 and 3 has even 4 solar panels on and generated even 20% of their own power, and there was enough to knock 5% of power use down in our country (world?), then it's a win.
There's no need to "go off grid" and raise your own goats for food and knit you're own underwear to use solar.
(Now, if you switch from CRT to LCD, you save having to buy $500 of solar panels...)
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Cool! (Score:3, Insightful)
Re:Cool! (Score:3, Insightful)
Re:Cool! (Score:5, Informative)
A.) Prices will go down if these things take off.
B.) Think of how much cheaper the electric bill will be. (Also consider how much more regular it has the potential to be.)
C.) Imagine if an ill-timed power outage wouldn't necessarily mean the building was affected.
I imagine once somebody sits down with a calculator and thinks out 5 to 10 years, the cost will end up being quite competitive AND they get bonus features to boot.
Just because something starts out at a high price doesn't always mean the value's not there, or that the price will always stay that way. The main reason I'm replying is not so much because of your particular comment, but because I've seen a great deal of sticker-shock on Slashdot without understanding some of these basic things about how technology economics works.
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Brainstorm (Score:5, Funny)
No Dumbass (Score:5, Funny)
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Does it play d00m? (Score:3, Funny)
How much does it cost (Score:4, Insightful)
Re:How much does it cost (Score:5, Insightful)
Actually, the question should probably be: How much energy does it take to produce a square foot compared to a square foot of glass? But the question probably isn't even relevant, I'm sure the price will be prohibitive anyway, at least for mass adoption. In general, you're right, of course: this "ecological backpack" is an important issue the public really isn't aware of.
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Re:How much does it cost (Score:5, Interesting)
1) How much does it cost to produce a square foot of this solar panel?
2) Same question as #1 for the glass that would be used normally?
3) How much energy will this solar panel -leak- over the expected life span of the installation?
4) Same as #3 for regular glass?
5) What is the energy gained by the solar collection process?
6) After all factors considered, is the cost of the solar panel compared to regular glass over the lifespan of both higher (bad) or lower (good)?
Illustration (all assumptions):
* Assume the installation has an expected life span of 10 years (I would hope the lifespan of skyscraper glass would be more like 40-50 years or more, but that is a pain to calculate).
* Assume that the glass installation costs $1,000 (we're talking a big piece of skyscraper glass here, ok?)
* Assume solar panel costs 10x the normal glass installation, $10,000
* Assume that each year the regular glass will cost 1/2 again the initial cost in energy loss (probably a pretty drastic assumption but it makes things easy)
* Assume that each year the solar glass will net 1/2 again the initial cost of -regular- glass each year (another drastic assumption)
Factored together, after 10 years the regular glass net cost was $6,000 whereas the solar glass net cost was $5,000 (and also helped subsidize the cost, making future installations less costly).
Of course, being assumptions you could easily make an example where the reverse was true and the solar glass was more expensive over 10 years (again, hoping that 10 years is a small chunk of the real installation).
My point is pretty small for all of the above
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Re:How much does it cost (Score:3, Insightful)
Re:How much does it cost (Score:5, Insightful)
Solar is attractive because it isn't seasonal (unlike hydroelectric, which is only available during a portion of the year and is usually unavailable during the time we need it most, summer). Solar is unsightly and takes up a lot of real estate, which makes local environmental lobbyists pissed, but where I live (Southern California), it makes sense because we have a perfectly good desert nearby and placing a solar panel farm out there is simple Trying to place one in downtown Chicago is made easier by the panels in this story, since they could be incorporated into most buildings that have a modern, glass-heavy look. But the problem there is that Chicago and many other urban cities don't get nearly enough sunlight to make a panel farm efficient, just like most most areas don't get enough wind to make a propellor farm efficient. Better panels may come along, but there will always be cities that have to rely on other forms of power (nuclear comes to mind, and maybe someday we'll get fission to work-bring on the Duke Nukem Forever jokes).
As for corn ethanol, not only is it wasteful of energy, it's typically more expensive than your average gallon of gas here in the United States. Have to agree with you there.
The trick is that you have to look at solar from a few angles. It isn't a cure all for our energy problems, but it has more than just a few 'niche' applications and it could help make a serious contribution once the technology has matured.
Wow, did I really write all of that?
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Re:How much does it cost (Score:5, Informative)
be lucky to get the things to last 5 years without breaking), then that momentary expenditure of oil will more than pay for itself.
Um, solar panels do in fact last that 20-30 years. [solarbuzz.com]
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Re:How much does it cost (Score:3, Informative)
Re:How much does it cost (Score:5, Interesting)
Kind of the opposite here in Ontario. The length of time the sun is out changes a lot. On June 20th of this year, the sun rose at 5:45am and set at 9:07pm (at my location of course). On December 20th of this year, the sun will rise at 7:52am and set at 4:52pm. The further north you go, the more drastic the changes.
Solar power should work out reasonably well even with those changes in daylight hours because peak electric use is during the summer where the most power is used.
Why is hydroelectric generation seasonal? It's my understanding that most of our hydro is generated using dams. Some is generated on rivers such as the Niagara River. Do your rivers dry up in the summer or something?
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Re:How much does it cost (Score:4, Insightful)
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Re:How much does it cost (Score:3, Interesting)
Not true. Both hydroelectric and wind are basically solar-powered. And neither of those have much in the way of a set lifetime, nor do they take large amounts of energy to develop.
There are also solar powerplants that use large arrays of mirrors to boil water into steam and run turbines. Again, I don't see these having any specific lifetime so there isn't any cost of recreation, just maintenance (which should be small)
As far as I know, it's basi
Re:How much does it cost (Score:5, Informative)
As for ethanol, I will raise you Cornell study with this one from the USDA [usda.gov] which seems to say that ethanol is energy positive.
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USDA Study? (Score:4, Informative)
Not that I'm a consipracy theorist or anything, but of course it does. That is the US Department of Agriculture after all. And we're talking about what? Corn ethanol? Hmm, corn is an agricultural crop.
Now, take a look at the first two bullet items from their mission statement [usda.gov]:
Do you honestly think they'd ruin a perfectly good opportunity for one of the largest food crops in the US by speaking badly of corn derived ethanol? Please...
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Re:How much does it cost (Score:4, Interesting)
You know what will release the world from dependence on oil? The oil running out. The only question is, will the replacement energy technology be ready by then, or will we be caught unprepared and reduced to Mad Max style barbarism for a few centuries?
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Re:How much does it cost (Score:3, Informative)
Re:How much does it cost (Score:4, Informative)
And how much energy does it take to produce a single square foot. There is a basic falicy that a lot of folks seem to miss ... The same thing holds for all current forms of solar energy.
Actually, this is a basic falacy that you have missed. While what you say is true for ethanol, it is not true for modern photovoltaics (and hasn't been for some time). [nrel.gov] As for photothermal, you are also dead wrong. [ecovillage.org]
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Fantastic (Score:5, Interesting)
The first is simply to make more efficient use of natural light! I stayed for a week in a new residence building at The University of East Anglia [uea.ac.uk] (Norwich, UK) and the building really intrigued me. It had hollow lighting columns running up to the top of the building, despite being a rather tall apartment. So there was natural light from the top reaching all floors. That definitely saves lighting costs.
So with approaches like that (using natural light as much as you can) coupled with clear solar panels, you could both use natural lighting and collect power for electrical lighting later on. Improve actual lighting with high-efficiency (85% +) white LEDs (last forever) or high efficiency fluorescents, and you've got one amazing power-efficient building.
The problem is that these supplies -- solar panels, white LEDs have large initial costs. As these costs come down we'll see lots of nice new interiors. I can only expect such things to become more common as people actually realized they're screwed for cheap power.
Re:Fantastic (Score:4, Funny)
Heh. Where I work, our computer screens light the room.
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Re:Fantastic (Score:5, Interesting)
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How much power would that be? And at what cost? (Score:5, Informative)
The article calls out a price of $45 per square foot, making the solar panels for such a building cost about $52 million dollars. Surprisingly cheap for that much electrical capacity, though the usage factor would be pretty low, what with it being dark at night and all.
Replying to my own post... tsk tsk... (Score:3, Informative)
Re:Replying to my own post... tsk tsk... (Score:5, Interesting)
Of the Gigawatt produced by a power plant, how much of it is lost to power transmission? I mean, if these powerplant-esque high rises are closer to the point of consumption, aren't they a tad more efficient than the traditional at-a-distance power plants?
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Re:How much power would that be? And at what cost? (Score:4, Informative)
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Re:How much power would that be? And at what cost? (Score:4, Insightful)
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Re:How much power would that be? And at what cost? (Score:4, Interesting)
It might take $900k/megawatt to build a coal fired power plant, but once built you still have to sustain it. Its costs will continue for the life of the power plant. Once you put solar panels onto a building, aside from a little light maintenance (har har) it's a one-time cost.
Aside from economical benefits, it's also more accessible and conveniant to be hooked up to power from your own building -- there nothing much short of a true disaster that would knock out your power. Being off the grid can be a very good thing.
And of course, factor in the environmental impact. How much coal do we really have left in the world? It takes nearly 100 tons of prehistoric plant matter to create a single gallon of gasoline. I don't know how much prehistoric life goes into coal, but how about let's just not waste it in the first place?
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Ummm... (Score:5, Informative)
"As an external glaze, PV-TV allows up to 10% visible light to be transmitted through the panel."
transparent Audio pronunciation of "transparent" ( P ) Pronunciation Key (trns-pârnt, -pr-)
adj.
1. Capable of transmitting light so that objects or images can be seen as if there were no intervening material. See Synonyms at clear.
Re:Ummm... (Score:4, Informative)
"Translucent" means that while some qunatity of light is allowed to pass, no meaningful image passes.
So it is possible to be both transparent and yet block some of the light - and for an example look no furthur than your sunglasses.
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...can generate 3.8 watts of electricity... (Score:4, Funny)
3.8 watts per square foot with what? (Score:3, Interesting)
Bright sunlight, regardless of angle?
Diffused light on a cloudy day?
In outer space, facing the sun?
They say absolutely nothing about the preconditions that are necessary to produce that 3.8 watts... and it's simply not possible for it to produce the same output regardless of its environment.
Um.... (Score:4, Insightful)
Mega-whats? (Score:5, Informative)
The factory is now the world's largest single PV module plant, producing 100 megawatts of energy annually.
A megawatt isn't a unit of energy, it's a rate of transfer. Do they mean that it produces a continuous flow of 100 megawatts? If so, they would have to have 604 acres of glass [google.com] (2.4 million of their 1m^2 panels). Of course you need to double that number because they're only collecting power half the day (generously assuming they're at peak output during all daylight hours)
On the other hand, if they're talking about generating 100 megawatt hours over the course of a year, then the plant is generating about 11,000 watts, or enough for about 10 average homes. By those numbers they'd have about 600 panels [google.com]. That's a lot more reasonable.
Wait a minute here.... (Score:5, Funny)
Arrrrgggghhhhhhh
Above average? (Score:5, Informative)
My Kyocera KC120 panels produce 12 watts per square foot, 3.8 doesn't sound above average to me.
Something is bogus (Score:5, Informative)
http://jsl.com/solar
Ah, I see (Score:5, Interesting)
This means that a 60W light bulb would need almost 16 square feet to function. Well, that of course is a reason to move to compact flourescents or LED light bulbs. But my computer takes up a bit of power. So does a refridgerator. So does a washer/dryer.
Let's say that it is a television. What's the equivalent of a square foot display (asuming a 5:4 ratio)? About 13"? Can a 13" LCD display work with 3.8W of power? (I don't know. That's why I'm asking.)
I'm not questioning whether it can give power. I'm questioning whether it can give sufficient power to offset the price. Or would the money be better spent elsewhere in green technologies to reduce the actual draw from the grid?
just cause (Score:4, Funny)
131,657,416,704,000,000 sq/ft
and cost
$5,924,583,751,680,000,000
in raw materials (maybe we could get a bulk discount)
we should also try to cash in on a "free installation"
The output of such a sphere would be
500,298,183,475,200,000 watts continuous
Or (for sake of easier calculation in an already complicated process) if only half of the sphere received light at any given time
250,149,091,737,600,000 watts continuous
250,149,091,737.6 kW continuous
250.15 Petawatt continuous
Power demand in 2002 for the entire world
13,747,393,531.8 kW continuous
0.0137474 Petawatt continuous
sure every living thing on earth would probably die and we would enter a perpetual ice age from the lack of light and heat but, you could throw away the sunscreen and with all that extra energy maybe we could string up some halogens or something along the inside! We could also sell advertising space on it.
All conversions made with http://www.onlineconversion.com/ [onlineconversion.com]
Power consumption data from http://www.eia.doe.gov/emeu/international/total.h
Geostationary orbit data from how http://octopus.gma.org/surfing/imaging/howhigh.ht
Radius of the earth from http://www.page.sannet.ne.jp/ikenoue/e-mode/earth
Output and cost from RFTA
If you think that my math is wrong then check and let me know, too tired to think anymore.
Re:Whats the point (Score:5, Funny)
Unlike horizontally mounted stuff which is good at night?
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Re:Whats the point (Score:5, Insightful)
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Re:Whats the point (Score:5, Insightful)
Still much better than regular glass that doesn't produce any power.
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Yeah Except (Score:5, Insightful)
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Re:Cover a building in it? (Score:4, Insightful)
Depends, you have to ask more questions:
1.) How much does the ordinary glass cost?
2.) How much electricity is generated? How much would this reduce the yearly bill?
3.) How much would/could electric prices rise?
4.) How long do these panels last?
5.) What other benefits are you buying? (I.e. is there resistance to power failures? Those in Cali during the rolling blackouts would appreciate that....)
6.) How does this compare to the cost of the rest of the building?
7.) Is running on solar power going to be attractive to tenants?
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Re:Cover a building in it? (Score:5, Interesting)
On an unrelated note, the Aon Center (formerly the Amoco/Standard Oil Bldg) in Chicago was originally clad in white marble. Years later, the climate softened the marble and bits of it began to fall off. So they re-clad the entire building with granite in the '90s, which ended up costing them more than the original price of the building. At least the electricity-producing glass could alleviate the utility costs of the building, but who knows how long it would take until the glass ended up paying for itself.
However, if it turned out that the glass turned out to be inferior to normal glass (visibility, thermal properties, etc), then the owners would have to go through the costly process of replacing it with regular glass.
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Re:Cover a building in it? (Score:4, Informative)
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