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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.
One m^2 of direct sunlight provides ~1000 watts, but due to the way things are, even the best solar panels can't get you more than, say 300 watts from that original 1000. Limits due to Carnot cycle apply.
That was the turning point of my life--I went from negative zero to positive zero.
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.
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.