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Solar Windows Could Help Power Buildings
Lucas123 writes: Several companies are now beginning to roll out translucent photovoltaic films or solar cells embedded in windows that can supplement a significant amount of energy in the buildings where they're used. SolarWindow Technologies, for example, is preparing to launch a transparent product made with organic PVs, while another company, Solaria, is cutting solar cells into thin strips and embedding them in windows. Both companies admit their products can't produce the 20% efficiency ratings of today's best rooftop solar panels, but they say that's not their objective. Instead, the companies are looking to take advantage of millions of skyscraper windows that today are simply unused real estate for renewable energy. One company is aiming at supplementing 20% to 30% of a skyscrapers power requirements. Meanwhile, universities are also jumping into the solar window arena. Oxford University has spun off a PV window company that produces semi-transparent solar cells made of semi-transparent perovskite oxide that has achieved a 20% solar energy efficiency.
You're also no mathematician
I know that you're joking, but I'm going to analyse your post anyway ;)
These are said to have barely over 20% efficiency at the moment. I can't find where it says how much light they block, so I'm just going to pull a number from thin air and say 50%. This means that your first layer works at 20% efficiency and functions as a window; the second layer will result in 30% efficiency and be a bit too dark to be a good window (and cost twice as much too); 3 layers would be 35% efficient, triple the price, and basically unusable as windows; 5 would be 38.65% efficient, ludicrously expensive, and usable only on a tiny patch on the roof when the whole point was to sacrifice some efficiency in order to be able to use the surface area on the side of the buildings.
But I like your way of thinking , especially since it raises the question of what would happen if you go past 5 layers and start generating energy from nowhere :)
Wait now... this dude is on to something. What would happen if they combined SIX layers?!
*mind BLOWN*
Cities don't have anywhere near the solar density necessary to make a dent in their consumption. There's just barely enough in a neighborhood, but when you get to multi-story density, it's a hopeless gesture.
It gets even worse when you use thin-films which have waaaay less efficiency than crystalline panels.
And it gets even worse when you mount them on vertical surfaces like skyscraper windows.
And it gets even worse when you have thousands of distributed pieces of small electronics that all must be maintained, managed and the energy combined.
I loooove solar and I can tell you it's just NOT WORTH IT. Make a big field outside the city and send the power in. Everything is a waste of time or just for show.
A lot of people have emotional feelings like, "but it's all just going to waste in the city." But use your head: It's all just going to waste out in the desert too. So be wise and put efficient, dense PV where there's lots of sun. Don't put inefficient PV distributed around where there's weak sun.
It's like trying to write a letter with twenty light pencils. Just use one dark pencil.
More than 5 layers would be unsafe, since the windows would then be operating at 120% efficiency and arcing sweet, free electricity all over the place.
Eloi are stupid, throw morlocks at them!
Just so long as it doesn't arc onto my lawn.
Suborbital [spaceflight] is the special olympics of spaceflight. - Rei
As the article noted, the double benefit of this system is not just the token energy it generates but the ability to better control HVAC costs by reducing the amount of heat that goes in through the windows, reducing demands on air conditioning in the summer. That being said, based on the pictures, this system is not pretty: the lines running through the translucent cells are rather annoying to look at and could be shot down by builders for the aesthetics alone. It would be better if they could deploy this as some sort of window shade that can be retracted to allow for unobstructed views (looking at the photos of the sample setup, it reminds me of the translucent shades used in a lot of newer offices), but I don't think this technology is there.
Carnot cycle refers to the efficiency limits of thermal generation or heat engines, ie a steam generator on a coal fired power plant or the efficiency of an internal combustion engine. PV panels do NOT operate on thermal generation and the Carnot cycle doesn't even apply. Other than that the rest of what you said was wrong.
Actually, 5 layers would be absorbing 67% energy (assuming the layers are 20% efficient for all levels of intensity/frequency of light).
1 - 0.8*0.8*0.8*0.8*0.8 = 0.67
The article talks about changing all the south facing windows in the office towers. It sounds great but in the city there's usually another tall building across the street blocking the sun so there's not much point in changing all of the windows. Maybe the ones near the top that does get the sun. I could see it being of more use in less dense areas but not in city centers.
Linux would use solar panels. The problem is where most pinguins live there isn't much sunlight.
Moderating "-1, Disagree" is simple censorship. Have the guts to post your opinion. -- Spazmania (174582)
As if they don't already routinely apply much cheaper coatings specifically designed to do that.
Limits due to Carnot cycle apply.
That is nonsense.
The Carnot Cycle is a principle of thermodynamic engines/systems. Which does not apply to a PV system.
Here we have a "photo electric effect" (guess who got a Nobel Prize for it?): https://en.wikipedia.org/wiki/...
The fact that our day PV panels have a "low" efficiency, comes from the fact that they only can react on/capture photons in a small bandwidth.
That has nothing to do with thermodynamics or Carnot, who -btw - as far as I know did not win a Nobel Prize.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.