Spherical Solar Cells Soak Up Scattered Sunlight (ieee.org) 61
An anonymous reader quotes a report from IEEE Spectrum: Flat solar panels still face big limitations when it comes to making the most of the available sunlight each day. A new spherical solar cell design aims to boost solar power harvesting potential from nearly every angle without requiring expensive moving parts to keep tracking the sun's apparent movement across the sky. The spherical solar cell prototype designed by Saudi researchers is a tiny blue sphere that a person can easily hold in one hand like a ping pong ball. Indoor experiments with a solar simulator lamp have already shown that it can achieve between 15 percent and 100 percent more power output compared with a flat solar cell with the same total surface area, depending on the background materials reflecting sunlight into the solar cells. The research group hopes its nature-inspired design can fare similarly well in future field tests in many different locations around the world.
Testing with the solar simulator lamp showed that the spherical solar cell provided 24 percent more power output over a traditional flat solar cell upon immediate exposure to sunlight. That power advantage jumped to 39 percent after both types of solar cells had begun to heat up and suffered some loss in power efficiency -- an indication that the spherical shape may have some advantages in dissipating heat. The spherical solar cell also delivered about 60 percent more power output than its flat counterpart when both could collect only scattered sunlight under a simulated roof rather than receiving direct sunlight. Additional experiments with different reflective backgrounds -- including an aluminum cup, aluminum paper, white paper, and sand -- showed that the hexagonal aluminum cup background helped the spherical solar cell outperform the flat solar cell by 100 percent in terms of power output. The new work is detailed in a paper submitted for review to the journal MRS Communications.
Testing with the solar simulator lamp showed that the spherical solar cell provided 24 percent more power output over a traditional flat solar cell upon immediate exposure to sunlight. That power advantage jumped to 39 percent after both types of solar cells had begun to heat up and suffered some loss in power efficiency -- an indication that the spherical shape may have some advantages in dissipating heat. The spherical solar cell also delivered about 60 percent more power output than its flat counterpart when both could collect only scattered sunlight under a simulated roof rather than receiving direct sunlight. Additional experiments with different reflective backgrounds -- including an aluminum cup, aluminum paper, white paper, and sand -- showed that the hexagonal aluminum cup background helped the spherical solar cell outperform the flat solar cell by 100 percent in terms of power output. The new work is detailed in a paper submitted for review to the journal MRS Communications.
Spherical solar panels (Score:5, Informative)
Not spherical solar cells!!!
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Not really new, not as useful as they think. (Score:2)
Not new, people have messed with these concepts for ages.
The bad thing is that you may get "24% more power" but it takes four times the cell area to do it. I don't know of any cases in which that trade works out in favor of spherical. By the way, you can't pack these tightly together, or you lose the advantage, so that "24% more power" does not translate to "24% less land area needed".
The place spherical (or other non-planar) cells are useful is that sometimes you want a flat power vs time profile, but do
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sometimes you want a flat power vs time profile, but don't want mechanical tracking
I suspect a lens is a cheaper solution for this use case.
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sometimes you want a flat power vs time profile, but don't want mechanical tracking
I suspect a lens is a cheaper solution for this use case.
I'm not sure how you figure that; lenses are very directional. Lenses--or concentration systems of any kind--require tracking.
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; lenses are very directional. Lenses--or concentration systems of any kind--require tracking.
I'm confused by this statement. A lens is a device that can accept light from multiple directions and concentrate it onto a spot, or do the reverse. A lens + tracking could do even better, yes, but it is certainly not required. The whole purpose of this experiment is to play with ways to do it *without* tracking.
A non-tracking lens-based approach might look something like this lighthouse lens solar concentrator [inhabitat.com].
Here is why you typically see lenses+tracking together: There are 2 types of photovoltaics. Co
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I'm confused by this statement. A lens is a device that can accept light from multiple directions and concentrate it onto a spot, or do the reverse.
Most of sunlight comes from one direction, the rays are practically parallel. If the sun moves across the sky, the direction of the rays changes. The focal point changes with it. So yes, a lens concentrates it onto a spot, but the spot will move with the movement of the sun.
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So yes, a lens concentrates it onto a spot, but the spot will move with the movement of the sun.
Yes, but the lens will make the spot move less than if there was no lens. Hence, the lens helps.
Lenses, once more [Re:Not really new, not as u...] (Score:2)
So yes, a lens concentrates it onto a spot, but the spot will move with the movement of the sun.
Yes, but the lens will make the spot move less than if there was no lens. Hence, the lens helps.
The opposite. A lens makes the spot move more (by a factor of the square root of the concentration factor).
Lenses [Re:Not really new, not as useful...] (Score:2)
; lenses are very directional. Lenses--or concentration systems of any kind--require tracking.
I'm confused by this statement. A lens is a device that can accept light from multiple directions and concentrate it onto a spot, or do the reverse.
I am confused by your statement. A lens is a device that accepts light from multiple directions and concentrate light from each different direction onto a different spot.
That's how a lens forms an image: you convert direction of light (the input), into different places on the focal plane. If the light from all different directions concentrated onto the same spot, lenses wouldn't make an image.
A lens + tracking could do even better, yes, but it is certainly not required.
If you have a lens concentrating the light, you need tracking.
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The best "lens" described in the summary is an aluminum cup. If I were assigned the task of producing the lenses on an industrial scale, I'd simply stamp a 4'x8' sheat of .050' 3003 to be a sheet of stamped cups. It would look almost like bubble wrap. The sheet would hold an array of spheres that would all be inserted at once.
A mechanical folding machine would make these easy if the panels were mounted on a malleable substrate. I don't know why they'd need something as complicated as a mechanical hand.
Re: Not really new, not as useful as they think. (Score:2)
Which is what it is all about, cheap huge scale manufacturing for vast Saudi deserts. I was camping in desert a few days ago, went from 105 to 45 in 13 hours, afternoon to predawn. I wonder if they could do something with energy from heat difference as well with such crazy fluctuations.
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From the article. "achieve between 15 percent and 100 percent more power output compared with a flat solar cell with the same total surface area"
So a beaded net of these, probably would generate more power than flat panels over the same square area.
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And probably at nearly the same cost. Remember that a huge part of the cost of a panel is the substrate and mounting hardware.
Projected area, not cell area. (Score:2)
From the article. "achieve between 15 percent and 100 percent more power output compared with a flat solar cell with the same total surface area"
If that's what the article says, the reporter misunderstood. That is wrong. Same total projected area, not total area.
The geometry they claim can't do that.
...I really do have to point out that this is not new; people have proposed this kind of thing for years. It is well analyzed.
https://inhabitat.com/revoluti... [inhabitat.com]
https://onlinelibrary.wiley.co... [wiley.com]
https://www2.humusoft.cz/www/p... [humusoft.cz]
https://scholar.google.com/sch... [google.com]
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Another application is for areas that are cloudy most of the time.
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No, it may not look like one, but it's a cell. They started with a flat cell and etched grooves to make it foldable. In any case, I'd argue that even a multi-cell assembly would be called a "cell" if it's intended to be the basic building block of a larger array.
What I find interesting/perplexing is the use-cases for such a thing. A *spherical* cell necessarily shades half it's surface area from direct light. Apparently one of the perceived advantages is that it collects reflected light behind itself.
Cell, array, panel, field (Score:2)
No, it may not look like one, but it's a cell. They started with a flat cell and etched grooves to make it foldable. In any case, I'd argue that even a multi-cell assembly would be called a "cell" if it's intended to be the basic building block of a larger array.
You could argue that, but you'd be using non-standard terminology. Individual cells are put together into panels, multiple panels are put together into an array (and multiple arrays are sometimes called a field.)
What's confusing is that there have also been proposals for solar panels made of large numbers of individual tiny spherical cells: https://scholar.google.com/sch... [google.com] . TI did a lot of development of that (I visited their research facility a few times, back in the day) but ultimately decided that t
Yeah, this is complete BS (Score:4, Insightful)
So essentially this is just a bunch of cells pasted to the outside of a nearly spherical ball. To make use of it, you have to suspend these in front of a reflector. So now you have a sort of box with these balls inside.
Now compare that to a traditional panel, where the cells are glued to a plate of glass on the front and a sheet of plastic on the back. If you have a reflective background, there are bifacial panels with glass on both sides. These are common in some ground- or roof-mount systems where they have a light background, often using quartz landscaping rock.
So, yeah, this is going nowhere.
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So essentially this is just a bunch of cells pasted to the outside of a nearly spherical ball. To make use of it, you have to suspend these in front of a reflector.
Right, you put the ting on a post above the ground. The rocks, grass, sand, or whatever on the ground is the reflector. That's because it uses scattered light.
There's lots of reasons to find this a stupid idea, this just is not one of them.
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There's lots of reasons to find this a stupid idea, this just is not one of them.
Not if they were nuclear powered balls, then they'd be awesome!
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You mean powered by that nuclear power reactor in the sky? The sun?
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Not if they were nuclear powered balls, then they'd be awesome!
You mean powered by that nuclear power reactor in the sky? The sun?
No, he's obviously talking about how awesome it would be if his balls were nuclear powered.
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Not if they were nuclear powered balls, then they'd be awesome!
You mean powered by that nuclear power reactor in the sky? The sun?
No, he's obviously talking about how awesome it would be if his balls were nuclear powered.
Hell yeah! Like the Energizer Bunny...
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> The rocks, grass, sand, or whatever on the ground is the reflector
Which is precisely how bifacial panels work today.
So this experimental system replicates that already-in-production system, but is much more complex and expensive.
> this just is not one of them.
It is one of them.
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These days the most important thing for most solar tech is price. There is plenty of available space, millions of rooftops.
There might be some specialist applications where a bit more energy density is important, but I can't think of any.
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These days the most important thing for most solar tech is price.
Agreed.
There is plenty of available space, millions of rooftops.
I thought you wanted to keep the costs down? Rooftop solar is 2x to nearly 10x the cost of utility scale solar, where panels are mounted close to the ground.
Cite: https://www.lazard.com/perspec... [lazard.com]
There might be some specialist applications where a bit more energy density is important, but I can't think of any.
I can, for powering probes on the surface of the moon or Mars.
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You have a really weird way of looking at these things. Who would be in the position of having to decide if there were going to use rooftops or ground based? Some utility company with a really really big office?
These are two separate markets and both are price sensitive.
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Rooftop solar is 2x to nearly 10x the cost of utility scale solar
No, not really. Maybe in the US where there's apparently some outrageous extra expenses associated with putting something on your own roof, but in sane parts of the world it's perhaps ~1.4x as expensive as larger-scale utility solar.
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> Rooftop solar is 2x to nearly 10x the cost of utility scale solar
Utility solar is paid the wholesale price. Rooftop solar is paid the retail price.
The opposite can also work (Score:5, Interesting)
Lower efficiency (Score:2)
Of course, as about 50% of the "panel" would be hit by fewer photons. ... bullshot!
To me personally that looks like
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I'm glad to see that you've done the appropriate research necessary to call bullshit on the pros.
Awesome Alliteration (Score:3)
Re: Awesome Alliteration (Score:1)
Comparison (Score:2)
Aliens of Cygnus 12b Gamma: Built a Dyson sphere around their star.
Humans of Earth: Built a Dyson sphere around an LED.
TED talk about different collector shapes (Score:4, Interesting)
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Thanks for that link!
TL:DW;
* @5:43 Six horn-like tubes feeding into a central cell
* @6:10 Can collect light from a +/- 25 degree angle
* @6:08 10% energy loss with each bounce
* @6:00 Maximum 3 bounces needed for extreme off-axis
--
The problem with Atheism is that is based on Ignorance. (No belief means no knowledge)
The problem with Theism is that it is based on Arrogance. (My god is bigger then your god.)
The solution is to develop your own spirituality where you find your own innate answers instead of mindles
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Solar energy generates energy cheaper than coal-fired power plants in some locations and depending on the time profile of power usage.
You say "problem solved!", but energy is not a single problem that can be solved once and done. It is a problem comprising ten thousand different locations with different applications with different requirements.
Various technologies-- better and cheaper panels, better and cheaper transmission, better and cheaper storage-- are at the moment increasing the number of places and
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Natural links (Score:4, Informative)
Sounds like there are some links to uses of fractal geometry in this.
A possibly related note - a short book called the 'The adaptive geometry of trees', by Horn in 1971 describes how trees and many smaller plants can get much more effective photosynthetic surface than the surface area of the ground that they occupy. Sometimes it's by simple tricks like inclining their leaves to the sun rather than facing it (as in blades of grass). Trees however can also make use of the penumbral zone of their upper leaves and leaves lower in the tree and thus partly shaded could still be working at maximum efficiency. Somewhere in the book is an account of how the distribution of chloroplasts can change in beech leaves, depending on light levels, to improve photosynthetic efficiency.
Similar to Solyndra (Score:2)
This concept seems similar to the Solyndra, cylindrical solar tubes except with a more complicated and likely more expensive manufacturing process. I would say it's unlikely this concept will find mass commercial success.
Solyndra already tried this (Score:5, Informative)
The problem is simple geometry. The total sunlight hitting a panel of any shape (and thus the maximum energy available to be collected) is just the cross-sectional surface area of your collector perpendicular to the direction of sunlight. By simple geometry, since sunlight only comes from one direction at a time, that cross-section is always a flat surface. So the smallest shape which can collect all the available sunlight is a flat surface. In practical terms, that means mounting flat solar panels on a rig which tracks the motion of the sun across the sky will out-produce any other geometry at considerably less cost (since you don't need to cover as much surface area with PV cells).
Other shapes can produce more energy than non-tracking flat panels. But once you factor in the cost of the additional PV cells needed to cover the larger surface area, the advantage disappears and actually turns into a disadvantage (the entire round panel may produce more energy than a flat panel, but each square cm of PV cells produces less energy over the course of the day than on a flat panel). If the primary cost of solar weren't the PV cells, then non-flat shapes might be competitive. But as long as the PV cells are the primary cost, it's cheaper to either mount your flat panels on a tracker, or to just build more flat panels and put them next to your existing ones. Exotic shapes like Solyndra's cylinders or the spheroids in TFA might make sense on some space-limited mobile platforms (where you're never sure of the direction of the sun so can't track it). e.g. Maybe aboard sailboats. But for mass power generation on land it's an economic dead-end. (At least until PV cells become dirt cheap. But at that point it'll probably be easier just to cover your entire exterior surface with PV cells, rather than make bulky spheroids or cylinders which are difficult to clean - remember, it's the cross-sectional area which counts, not the shape. A sphere or cylinder just appears to be attractive because they present the same cross-sectional area all the time. But their additional gain over flat panels are at extremely low angles - e.g. sunrise and sunset, when most of the energy in sunlight is being scattered by atmosphere so there's little to collect anyway.)
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By simple geometry, since direct sunlight only comes from one direction at a time [...]
FTFY.
From what I read, the benefit of something like this is that it can also pick up reflected light. So if you're in a particularly bright area (like, I dunno, a desert) something like this might be easier to maintain than a flat panel with motors. It could also be useful, as you mentioned, on a sailboat. Another possibility would be urban/suburban environments. Mount this on the top of a street-light and collect energy throughout the day to run the street-light at night. The city I live in has over
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Solyndra [wikipedia.org] tried making semi-cylindrical solar panels to accomplish the same thing. They failed in what was probably the biggest green subsidy scandal of the Obama administration. The problem is simple geometry. The total sunlight hitting a panel of any shape (and thus the maximum energy available to be collected) is just the cross-sectional surface area of your collector perpendicular to the direction of sunlight. By simple geometry, since sunlight only comes from one direction at a time, that cross-section is always a flat surface.
CIGS deposition is insanely cheap (low efficiency, but cheap). Solyndra assumed that their thin-film CIGS tech deposited the photovoltaic film at such a low cost that the cost per unit area of the photovoltaic element itself was negligible. I think that their technology was a long shot, since their effective efficiency ended up being lower than most users required, but the real reason that they lost was simply that the price of silicon panels dropped so much that they couldn't compete.
In practical terms, that means mounting flat solar panels on a rig which tracks the motion of the sun across the sky will out-produce any other geometry at considerably less cost (since you don't need to cover as much surface area with PV cells).
Right, except for th
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> benefit of something like this is that it can also pick up reflected light
So can existing panels:
https://www.solarpowerworldonline.com/2018/04/what-are-bifacial-solar-modules/
They've been around for years. Google "bifacial panel".
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In practical terms, that means mounting flat solar panels on a rig which tracks the motion of the sun across the sky will out-produce any other geometry at considerably less cost (since you don't need to cover as much surface area with PV cells).
I'll nitpick here a bit. There's 2-axis and single-axis trackers out there. A 2-axis tracker will track the sun more accurately as it's arc changes with the seasons but these cost more to build and maintain, and this cost is rarely justified given the income from the higher energy collected. Single-axis trackers mean taking a compromise on the arc it takes, and therefore energy collected, but the simpler construction means a cost savings that makes up for this loss.
So, yes, indeed a 2-axis system will ou
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> So, yes, indeed a 2-axis system will outproduce anything else but the costs over a single-axis system is rarely justified.
Or more simply:
The angle of the sun east-west changes 180 degrees every day*.
It changes 53 degrees north-south per year.
Which would you think you should optimize for?
* It does not change 360 per ''day''.
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But let's say tracking is not desired for several reasons, such as cost and maintenance, then what surfaces can help? It's a bit premature to claim we've hit perfection with a flat panel and tracking and that more research is unnecessary. There is most definitely a need for immobile solar panels that can continue to generate electricity even as the sun moves, there's a need for panels that don't block all the light to the ground, and so forth. Maybe a design takes up more actual area of generating surfac
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> definitely a need for immobile solar panels that can continue to generate electricity even as the sun moves
Those exist, they're called "solar panels". The panels on my garage produce power from before sunrise to after sunset and they're firmly immobile with some McGuivered unistrut.
> there's a need for panels that don't block all the light to the ground
You can buy those too, they are used in special purposes like greenhouses and such.
What is the point (Score:1)
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I'm wondering the same... Why not make it half a sphere, use the lower half for a second collector, and place a mirror under each half to back-light it.
Chinese copying old tech that isn't practical (Score:2)
So, a Chinese student copies the old spherical lens concept, which has been around for decades. What will they do next, try to patent circles?
Oh boy! Solyndra 2.0! (Score:1)
Wonder how much this company will cost taxpayers.
Little known fact (Score:2)
The Drake Equation is not named eponymously. Frank Drake actually named it after the detective character in his favorite TV show, Perry Mason.