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Solar Window Panes
Val42K writes "Now, those windows that allow glare onto your computer screen can be useful. They will provide power to your computer, air conditioning and other useful necessities. Energy conversion rates are 'way more than 50 percent'."
there are a lot more roofs and walls than windows and roofs are better situated wrt the sun. Therefore photovoltaic roofing would always be a better idea.
This looks pretty cool, but reading through the article I don't really see exactly how much eletricity these will produce per window. Will they make a significant dent in the power costs for a typical household? The cells may only be a quarter each, but how much will it cost to embed them in the windows and collect the power?
Twenties Retirement
Check out the pictures to the left of the main story. There's a noticeable difference in light intensity between parts of the window with clear glass and those with the embedded miniature solar panel, leading to a mosaic light pattern. This sort of thing is fine (and maybe even artsy) for an office foyer, but won't be widely adopted in office windows (which make up the majority of downtown buildings) because it's horrible for reading or working in. Your eyes can't tell if they should adjust for the bright or dark spots.
The bold print giveth, and the fine print taketh away
How can the window both let the light trough and get energy from it? I really want to see the technology behind that bit of genious. I understand how a dam uses the movement of the water for energy but to suck the energy out of light is blowing my mind.
-Tim Louden
I don't believe this story for a second. Not a bit.
For decades I have been folowing solar cell technology, absolutely salivating at the promises that efficiency rating would soon rise above 15%.
Well, I've given up. I've read shitty pie-in-the-sky stories like this almost every year for the last 25-years.
Now, if someone on Slashdot tells me that they bought these +50% efficient solar cells in Home Depot, that's when I'll get excited. Like I'll get excited when Chevrolet markets a flying car or my city puts a nuclear fusion power plant into service.
Chill out guys, it ain't real 'till it's real.
--Richard
Do a Google search on solar cell window and you quickly realize that this is an old idea.
Absolutely. Very old idea. However, do a Google search on commercially available products in this space and you quickly realize that this an old idea that hasn't really been commercially developed. You could chalk that up to the dangerous imprecations of the 'old girls' network, but I think it's just a problem that hasn't been solved yet in a cost-effective manner. Which is why money is still being spent looking into it.
But what's important this time I guess is that it's a woman who "discovered" the idea.
I don't see why you would conclude that. I can think of two reasons this article might be important:
Note that those two options are not mutually exclusive.
Bullshit. Current conversion rates are about 18%, and haven't changed much in 20 years or more; they've slowly managed to squeek out more and more power getting up to the current 18-20%, but nowhere near 50%. Let's put this in perspective- it would be like someone claiming they could get 100mpg in their car, and "easily 200mpg".
The bullshit-o-meter goes off the scale at the claim they can get "100%"- and there's one very simple, indisputable reason; the glass itself blocks a significant amount of energy- ESPECIALLY at a low angle of incidence, where the outer glass is going to reflect a large percentage of the light hitting it. The modules inside the window may pivot, but the outer glass doesn't.
The bullshit-o-meter EXPLODES at the nice little bit about how they won't discuss specific energy conversion rates in detail. It doesn't help that this is being published in Science for People Who Think They're Trendy(aka Wired). Ring me when she's published results in Nature or (gasp) a professional journal.
Oh, and if I wasn't pessimistic enough :-)...if this actually DOES pan out...just wait until you see the price tag on 'em, because I'm sure she's going to patent absolutely everything out to wazoo, and one company will get exclusive rights. It'll also be years before we see 'em, as said company will want to protect its investment on current solar panel technology...
Please help metamoderate.
> For the researcher to generally state 'way more than 50%' rings alarm bells in my head.
I'm with you on this one, as it seems highly suspicious that this group has been able to produce ultra-efficient solar cells. Beyond that, I don't see the point of integrating these panels into a window - that just seems complex, unnecessary, and certainly has to be more expensive than a regular window paired with a stand-alone solar cell.
My take is that this idea will not succeed. Nobody will be willing to spend the money to replace the windows in existing buildings, and future construction will probably not be interested in spending more money for integrated solar-window things without some reality to back up these efficiency claims.
Um, yeah right.
Even 50% is staggering. Heck even 35% would have been quite impressive. Why is my BS meter hovering around MEG right now?
Don't get me wrong, I know they work and are real but I seriously doubt the efficentcies they claim.
and many places aren't suitable for hydro generation. and many more places lack fossil fuels. so?
when it comes to alternative energies, we aren't looking for one silver bullet. a solid energy programme will rely on a diversity of generation methods as well as consumer and industrial-level conservation measures. when it's windy, use wind. when it's sunny, use solar. when neither is available, fall back on hydro or (god forbid) coal. and, of course, conserve, conserve, conserve.
the last time we had a grand-unified-energy-solution it was "too cheap to meter" nuclear power.
oops.
2 1337 4 u!
So, according to you God doesn't mind us stinking up the planet with fossil fuels, but he objects to us using our God-given brains to figure out how to get energy directly from the Sun which He created? Funny, then, that He created trees, which employ a bunch of fancy chemistry in order to derive 100% of their required power from solar energy.
I've done a great deal of research on the topic of solar energy and have a pretty good understanding of physics. To the average person, this article sounds wonderful - super efficient solar panels, a total breakthrough! To me, it's pretty easy to see this article either grossly misquotes the researcher or the researcher is completely crazy.
From the article: "Ultimately, Dyson is confident her team's solar cells can reach nearly 100 percent efficiency -- compared with typical solar panels' conversion rate of less than 20 percent."
100% sounds great. Except they forgot that glass absorbs/reflects a minimum of 10% of the light, much more at non-direct angles. And that getting any semiconductor (solar panel) surface to absorb all light hasn't yet been possible - assume another 15% is lost here. And of course, to be able to actually see through the cells (they're "translucent"), we'll assume 20% light transmission. Then you need to think about things like entropy and expect a nice loss in this process, we'll be generous and figure 10% loss.
Just adding the percentages shows 55% efficiency by simple addition. And this is with everything ideal. And now consider that the _best_ solar experiments have approached, under super-controlled situations, 40% efficiency.
And top all this off with no demonstration of the product itself and no details on their technology, it's another vaporware article.
I can't say for certain, but my guess would be that it's because these are always perpendicular to the sun, it can get the maximum energy from it, as opposed to panels on houses which are fixed and will probably average 10% since they can't move with the sun.
Things you think are in the Constitution, but are not.
The glare that once bounced off your computer monitor no longer exists. And the sun's intense heat, which once led to window-shade tug-of-wars with co-workers longing for a little natural light, no longer beats down on you. You comfortably tap at your keyboard under natural, abundant, ambient light.
Do the math...one cm^2 out of one ft^2 still leaves 99.9% of the area uncovered. How does this stop glare or solar heating?
Interesting. How does accepting Jesus fit into any of the quotes? Its basically...
Do this good thing,
Do that good thing,
Do this other good thing,
um... accept Jesus!
A deep unwavering belief is a sure sign you're missing something...
Both on a whole are generally vapourware..
Lots of spin associated with both..
If they ever get off the ground, they deliver only about 20% of what is promised..
It's going to be left to some poor development people to try and implement some impossible idea that some marketing wanker was claiming...
Doesn't take much to show that both are highly broken...
Both need almost weekly cleaning..
Each stops working in 8 hours or less and needs a daily restarting...
Each is a rip-off of other people's ideas - and poorly implemented...
Lots of incorrect positive rubbish gets written about them in Wired...
Patents Patents Patents....
and
There are much better ways already out there of doing what they claim.
Problem: while very small cells can be made much more efficient than the larger cells used in non-concentrating systems, I don't see how they can say "100% efficiency" with a straight face. 30% is pretty hard to get in production cells... even the tiny ones used in concentrators.
Problem: Tracking implies moving parts. Ever see a device with moving parts left out in the baking sun for years? They don't keep moving very well. Tracking the sun in two angles is a particularly expensive and unreliable operation... and if they build millions of these things for office buildings, you can bet a large fraction will stop tracking before long. Ever averaged a couple of "100"s with a whole lot of "0"s? I've seen it, and you get a low production level and a general impression of flakiness, and I am not talking about pie crust.
Problem: Solar cells don't individually produce very much voltage... so they need to be strung together to make an "array" that can produce enough voltage to feed an inverter for connection to the ac mains. Let one cell get a shadow, or the tracking be off a little, and it will be the weak link in the whole chain, possibly eliminating any output from the whole array. Random variation in individual trackers wiil exacerbate this problem to the point where required tolerances for will be... well, intolerable. Yes, bypass diodes can mitigate some of this mismatch, but these things add up very quickly.
Flat plate solar is working today, although it is probably still 50-100% more expensive than Iraqi fuel-oil-produced electricity. It isn't 100% efficient, and if the installer isn't well trained you can end up with a big goose egg, but it is pretty widely usable now. Just make sure your expectations are that the mismatch and other expected losses mean you should be prepared to get 70% of the manufacturer's rated output by the time you read your energy meter, and do the math. (There are a lot of reasons for this apparent overrating... it is just the way this technology works.)
Concentrators, unlike flat plate, are uncommon, difficult to install, and easily disrupted. Don't hold your breath for "100% efficient" solar from these people.
She is leading a team of researchers who are trying to prevent future power failures by making energy-sucking office buildings ultra-efficient at peak hours. (From the article)
I'm here working, and I am the only one on a floor that holds 200, and EVERY light in the place is on. Also all the other 6 floors of the two adjacent buildings are running. What's worse, I couldn't even tell you how to turn off even a section of these lights, as there are no visable light switches. My company is just wasting power... All I really need at my desk is my two lamps and nothing else.
This article is clearly a pie-in-the-sky dream.
... including Persian Gulf defense prior to W: $35.2 billion
Solar power, however, isn't. There is a lot of promising research in the field, and higher efficiency panels are possible (over 20%, not near 100%). But research continues on shoe-string budgets.
Some rough numbers:
Yearly direct oil industry subsidies in the mid 90's: $11.9 billion
W's proposed budget for developing alternatives:
solar: $42.9 million, wind: $20.5 million
These numbers were found with google and shouldn't be taken as gospel truth, though I believe they are roughly accurate.
The solar chips, probably about a centimeter or so square, would be spaced inside a square foot of unfiltered window. 1CM^2 gets at most about .1W, and that's momentarily at "solar noon", dropping off fast. A giant window, say 10x10', could collect a theoretical max of 8W, which wouldn't be enough power to even blow the inside air along the inside surface of the glass, let alone cool it.
Plus, any "near 100%" efficiency claims for wideband (sunlight) transduction are suspect, as even the best narrowband microwave transponder pairs are at best ~90% efficient (and very expensive). Then consider how that 100% efficiency contradicts the statement that they are "translucent", and I wonder why I even bothered to justify this insipid report about a (solar) fusion scam with a post.
--
make install -not war
This nice bit of technology (but bad engineering) will never make it in the real world. Pigeons, spiders, wind, snow, urban grime, clumsy cleaners, and assorted urban insults (taggers, vandals, inquistive slashdotters, etc.) will doom any of these solar window installations to the scrap heap inside of a year or two. Their structures look far too flexible and intricate to survive real world applications.
Don't get me wrong. I would love a cheap, reliable source of solar power. And I don't care about efficiency, because it is only tangentially relevant to the real measure of solar cell feasibility. I only care about long-term TCO and the effective ROI. Give me a coated, 5% efficient solar cell plastic film that costs 10 cents per lifetime kWh and I will coat every square inch that I have ownership of. Until then I will say "just what I need; another complex costly subsystem on my building."
Two wrongs don't make a right, but three lefts do.