Slashdot Mirror
MIT Study Outlines a 'Perfect' Solar Cell
Daniel_Stuckey writes A new MIT study offers a way out of one of solar power's most vexing problems: the matter of efficiency, and the bare fact that much of the available sunlight in solar power schemes is wasted. The researchers appear to have found the key to perfect solar energy conversion efficiency—or at least something approaching it. It's a new material that can accept light from an very large number of angles and can withstand the very high temperatures needed for a maximally efficient scheme. Conventional solar cells, the silicon-based sheets used in most consumer-level applications, are far from perfect. Light from the sun arrives here on Earth's surface in a wide variety of forms. These forms—wavelengths, properly—include the visible light that makes up our everyday reality, but also significant chunks of invisible (to us) ultraviolet and infrared light. The current standard for solar cells targets mostly just a set range of visible light.
Is this the least helpful summary ever on /.? It could be. I read it, and found it really didn't tell me anything I didn't already know, and gave very little clue as to how this study's results might even be helpful. I have a strong suspicion it's clickbait and so am moving along.
Hard to tell, would depend on how it ramps up in large scale industrial application.
Interesting 85 percent absorption rate, though. Most of the PV growth in solar has been using cheaper materials, not efficiency of absorption.
-- Tigger warning: This post may contain tiggers! --
i think the most important feature for this technology would be cost/kwh. does it deliver that ?
(surface area we have enough of)
Yes, I'm left. You have a problem with that?
This system uses blackbody emission to re-radiate absorbed photons within a specific bandwidth, which can be selectively optimized for.
However, since it uses blackbody emission, it does not explicitly NEED light as the energy source. Any kind of heating will suffice. This is really just a very fancy means of converting entropic energy into something useful. Could be very useful when coupled with radio-isotope decay systems, for instance. (This, coupled with existing RTG tech, could produce more efficient RTGs)
Sadly, it requires that large numbers of useful photons be produced from the emitting blackbody source, which means it needs some pretty non-trivial temperatures. This isn't going to be something that is used in normal residential settings.
As I read the MIT statement the researchers claim is that their technique collects energy as heat from all available wavelengths. Then a conventional solar cell is used to generate electricity from the photons emitted from the heated collector. I didn't see anything about how much more efficient this is than generating electricity directly, but presumably it's better since the solar cell responds best to a specific wavelength which can be controlled by using the heated collector. Obviously to make it work need a concentrator.
limits the thermodynamic performance of heat engines to n=1-T_ambient/T_solar ~=1-293K/1000K=70%. Now there are going to be losses converting hot liquid into useful work (electrical energy), so actually probably around 30% efficiency will be achievable. High performance photovoltaics can reach 40% efficiency, and therefore this article is highly misleading.
... from whose perspective? At least one perspective holds that the perfect solar cell is one that doesn't even work, a thin strip of plastic made to look like a solar cell that costs a helluva lot less than the real thing:
Today I was walking home from an errand to a store.I saw the remains of a “Dual Power Calculator” in the gutter; it had an intact solar cell in the top.“Cool!”, I thought; “I’m going to rescue that solar cell for some DIY thing.”I grabbed the top part and tossed it in my bag.
When I got home, I dismantled it to remove the “solar cell”.I discovered that it was a fake, a thin strip of plastic separate from the body made to look like a solar cell.
WTF....
Walmart already puts solar panels on many of their stores: http://cdn2.tekgoblinmedia.com...
Besides generating electricity, the panels protect the underlying roof from sun exposure, thus extending their useful life. When they run out of rooftops, they can start on the parking lots. This not only generates more electricity, it provides covered parking. In sunny states this is very desirable. Once electric cars become more popular, charging stations powered by panels above the parking lot will be another desirable feature for customers - shop and recharge your battery at the same time.