Tubular solar: Cylindrical solar cells, which can be arranged in rows to make solar panels, are particularly suited for generating power atop commercial buildings.
Solyndra
A startup is selling cylindrical solar cells that can generate more power than conventional panels.
Solyndra, a startup based in Fremont, CA, has developed a novel type of solar panel that's cheaper to install and produces more power than conventional panels.
Unlike conventional solar panels, which are made of flat solar cells, the new panels comprise rows of cylindrical solar cells made of a thin film of semiconductor material. The material is made of copper, indium, gallium, and selenium. To make the cells, the company deposits the semiconductor material on a glass tube. That's then encapsulated within another glass tube with electrical connections that resemble those on fluorescent lightbulbs. The new shape allows the system to absorb more light over the course of a day than conventional solar panels do, and therefore generate more power. What's more, arrays of these tubes offer less wind resistance than conventional flat solar panels, which makes them easier and cheaper to mount on roofs, the company says.
Chris Gronet, Solyndra's CEO, says that these advantages ultimately reduce the cost of generating solar power, although he won't say by how much. The company has raised $600 million in venture funding and has orders for $1.2 billion worth of solar panels, which it sells through installers exclusively for commercial rooftops. It started shipping its products earlier this year and is now ramping up production at its factory, which will eventually produce enough solar panels every year to generate 110 megawatts of electricity. The company soon plans to start construction on a 420-megawatt-capacity factory.
Solyndra is one of several companies that have recently received hundreds of millions of dollars to develop thin-film solar cells. Miguel Contreras, a senior scientist at the National Renewable Energy Laboratory, in Golden, CO, which developed the semiconductor deposition method used by Solyndra, notes that several other companies have developed solar cells based on thin films using the same combination of semiconductors; these thin films are making possible a range of new forms for solar cells, including flexible solar cells and solar roofing materials. "There's a lot more flexibility with thin films than there is with [conventional silicon] wafer technologies," Contreras says.
The cylindrical solar-cell design has a number of advantages for generating solar power on the flat rooftops of big-box stores, warehouses, and other commercial buildings. Ordinary flat solar panels can catch the wind, so they must be bolted or weighed down with ballast. Solyndra's panels consist of rows of cylindrical tubes with spaces between them that allow the wind to pass through, decreasing wind loads and making it unnecessary to bolt or weigh down the panels, even with winds up to 130 miles per hour, the company says.
IBM researchers have greatly increased the performance of a novel thin film solar cell.
Interesting, But Short On Specifications
The complete lack of efficiency, electrical, weight, indeed even dimensional, specifications raises credibility questions about Solyndra's product for me. It would seem that, if Solyndra were proud of their technological achievement, they would be forthcoming with details. There are a few clues in this October 6, 2008 article: Solyndra reveals thin-film solar tubes and this Scientific American article. However, it would seem that three key members of the technical side of the company have recently left Solyndra. And it would seem that Solyndra is looking for increased capitalization in in today's turbulent worldwide economic situation.
Non-silicion-based cylindrical cells
If these cells are able to withstand high winds, why would they be suitable mainly to commercial buildings? Is there any good reason not to use them on individual private homes? They might be out of place on the roofs of traditional cottage and colonial homes, but what about modern, post-modern, deconstructive eco-style homes? Cylinders are not inherently unattractive. Wouldn't they challenge good architects to incorporate them inthe basic design of domestic architecture as well as commercial?
Re: Non-silicion-based cylindrical cells
For one thing, the system really works best with a special type of roofing material used on commercial roofs. You need a reflective surface to make best use of the cylindrical design.
It seems clear to me that the claim: "The new shape allows the system to absorb more light over the course of a day than conventional solar panels do" is false. Flat panels laid flat on the roof would collect more energy. Flat panels angled to catch the noon sun would capture slightly less energy per square foot of roof area, but would capture much more energy per square inch of solar film area. Considering the cost of the solar film compared to the cost of the roof area, I'd say angled flat panels are a much better deal.
But I do like the idea of cutting the panels into narrow strips with air gaps between and mounting them low to the roof to reduce wind loads. That may reduce installation costs dramatically.
Re: Cylindrical is not efficient
Just a thought. The tubes are filled with a clear oil. That being the case , wouldn't this follow Snell's Law of Angle of Refraction? A beam of light bends in the opposite direction. So the light hitting the tube from the side at any angle, in this case infinate angles, the light would bend causing it to go directly into the solar panel (tube). Hense, no need to track the sun (angle).
Re: Cylindrical is not efficient
My concern would be what happens to these glass tubes in a hail storm? Also, how about what's inside these tubes, if released, what kind of pollutant would spill and what cost for clean up?
nothing odd about raising capital
if they have 1.2 bn$ in orders, and a 2-year backlog, one would hope to god they were making an effort to raise capital, regardless of the state of the credit/equity markets, because it is obvious that anything but a maximum effort to increase production capacity is a gross disservice to the investors.
what is truly wanting is a good survey of the cost/benefit and application profile of each of the now many solar power systems on the market, along with the supply chain issues associated with each.
Re: nothing odd about raising capital
>>>if they have 1.2 bn$ in orders, and a 2-year backlog, one would hope to god they were making an effort to raise capital, regardless of the state of the credit/equity markets, ...<<<
I agree that the requirement for additional financing is obvious, but to overlook the current frozen state of the world's financial marketplace is an act of delusion. The question is, how will the inability to raise the necessary capital to meet existing booked orders financially impact the firm.
its the bottom line, how long will they really last, will they pay for themselves in there life time. are they cost effective.
how does the turn key operational cost per watt compare to nuclear?
i hope one day all buildings, res and com, are roofed with solar panels.
What is a strange thing, that nothing was known, no publicity at all for this company right until October 07, 2008. Not a single article or even web site. And in a blink of an eye they claim they got 1.2 billion orders backlog and ready be delivered product...
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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fearless_fool
3 Comments
capturing more light
KB says: The trade-off, of course, is that the other side of the cylinder is shaded.
Perhaps the bottom half of the enclosing glass cylinder could be made reflective.
- ff
Reply
matthew393
1 Comment
Re: capturing more light
According to the company:
Solyndra panels employ cylindrical modules which capture sunlight across a 360-degree photovoltaic surface capable of converting direct, diffuse and reflected sunlight into electricity.
See the illustration here
Would placing a mirror-like material under the panels increase electricity generation?
Reply
Kevin Bullis
177 Comments
Re: capturing more light
The system is actually designed for use with a type of roofing material that's becoming more common. It's white to reflect light and save on AC costs. From page 2 of the article:
"The trade-off, of course, is that the other side of the cylinder is shaded. With highly reflective white roofs, however, this is less of a problem. Light passes through the same spaces between the cylinders that allow wind to flow through. It reflects off the roof and is absorbed by the shaded side of the solar cells. Also, the other surfaces of the solar cell absorb some diffuse light from the sky."
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