Neat Solar cells: where on earth do you get them ( in small quantities)

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I'm all fired up with articles describing High voltage Silicon multijunction Solar cells, for use with concentrators at high intensities.
Also GaAs units and monocrystalline Silicon units like the Sun Power A-300.
Does any one know where a simple mortal can get these in small quantities for experimentation?

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,474 admin
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    For the Sun Power, there is their website:

    http://www.sunpowercorp.com/

    Their panels look nice, and have very good ratings. Other than their website contact form, I did not find a vendor.

    To start a conversation--Why do you like the Sun Power panels ? Have you found their pricing to be good? Their temperature rating seems better than, for example, a BP 4175, and they appear to be guarantting the output level over 25 years--not 80% of power after 25 years like the BP (220 watts for Sun Power vs 175 watts for a BP panel of about the same physical size). Or is there some other reason you like them?

    Regarding the HVSMSC's... Do you have a link to an article of interest to you? Much of what I have read about concentrators does not seem to be of great interest to me as residential or small commercial installation. Usually, if the heat issues of a concentrated sun on a solar junction does not cause short life, then there is the problems of building and maintaining a reliable tracking unit over time, temperature, and weather.

    So far, of the current crop of solar PV panel trackers, many seem to get abandoned after a few years because of repeated component failures (several of the abandoned arrays I saw were at a popular solar exposition center):

    http://www.solarliving.org/

    What is it you would like to do with them?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    bb,
    those cells from sunpower are not concentrator cells. the only ones i've heard of were i believe from an australian company and i am not sure where that thread is that we talked of it. they used lens on the cells and as you said it will shorten up the life of the cells and you would need to track the sun or the light won't be focussed onto the cell for proper power to be produced. they had 10yr guarantees on those high priced amorphous cells so that should tell you allot.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,474 admin
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    Hi Niel,

    Yes, I understand the Sun Power are "regular" solar panels, 25% more power (per sq. than the BP model) and somewhat "blacker" (for architectural uses). The Sun Power link has some spec. sheets for them.

    Without knowing the price and availability--one cannot really make any descisions on whether or not to install them.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    that i really don't know. i haven't heard of anybody with them to know of their reliability or pricing. i'm not really too sure on how(if) the cell actually works as i've never seen one doped and tapped for + and - in such a manor.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    ba,
    that's a good question for on the sunny side it will be very high in temperature and on the back side it will be the extreme cold of space. do they cancel? do you know somebody at nasa to ask these questions? attempt at humor to follow: houston, we have a question. beep
  • BB.
    BB. Super Moderators, Administrators Posts: 33,474 admin
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    Cruised the web for a little bit looking for Solar Cells in Space Applications and did not find too much technical information. Most of the standard information about silcon based (the cheap ones we typically use) talked about radiation and voltage plasma/corona charges that damaged the cells. Ga-As type cells were several times more efficient, less affected by temperature (1/2 the derating per degree C vs silicon) and radiation, but cost 10x the silcon type cells (still a good deal for space applications).

    I did find a nice summary of a test of an array using concentrating (glass lenses at ~7-8x) lenses from 1998 (supporting Ion engine flight test) that had some numbers... For the most part, it appeared that the operating temperatures were not much different that we would see here (maybe 30-70 degrees C), and a -125C to +110C maximum stress test (only 5 cycles or so--some samples received different limits for testing).

    http://www.tsgc.utexas.edu/archive/subsystems/power.pdf

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    If you have the chance take a look at the Photon International magazine, page 68. I think there is some very important info in the article in reference to the SunPower modules.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    alana,
    i am having great difficulty in trying to view the article. could you copy and paste it here for all of us to read it? if you think there would be a copyright problem send it to me either by personnal message or by email.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,474 admin
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    Is this the SunPower press release that you are talking about?

    http://investors.sunpowercorp.com/releasedetail.cfm?ReleaseID=182021
    SUNNYVALE, Calif., December 15, 2005 – SunPower Corp., a Silicon Valley-based manufacturer of the world's highest efficiency, commercially available solar cells and solar panels (NASDAQ: SPWR), today announced its largest ever product supply contract. The supply agreement with PowerLight Corp., a global solar systems provider, calls for the delivery of $330 million of solar panels from 2005 through 2009. SunPower's industry-leading products will be incorporated into PowerLight's advanced solar power systems for commercial, government and new home residential customers worldwide.

    "This agreement marks another milestone in SunPower's growth strategy as we continue to build out our global customer base," said SunPower CEO, Tom Werner. "PowerLight is a widely-respected market leader and we are thrilled to be able to marry our high-efficiency solar panels with their innovative solar system designs and product offerings."

    The contract covers a variety of SunPower solar products to be incorporated into PowerLight projects worldwide as well as in their home state of California. A significant product covered under the contract is a custom-designed solar panel used in PowerLight's SunTileTM roof integrated system for new home construction. Using SunPower's uniformly black A-300 solar cells, SunTileTM interlocks with roof tiles and shingles to provide an aesthetic, architecturally seamless look for sunlight-to-power solar technology. The contract was signed at the end of the third quarter of 2005. Volume deliveries under the contract begin in 2006 and ramp up with SunPower's planned capacity expansion. "SunPower's high-efficiency solar technology improves the financial and performance equation of our products and systems," noted PowerLight's President, Dan Shugar. "We're focused on delivering maximum value to our customers and SunPower's technology fits perfectly with our application platforms."

    There was also this on the web about SunPower:

    http://thefraserdomain.typepad.com/energy/2006/03/cypress_solar_p.html
    Cypress: Solar Power to be Competitive in Five Years

    Solar power will be competitive with mainstream electricity generation method in five years according to Cypress Semiconductor, which has a solar cell manufacturing subsidiary, SunPower. Norm Taffe, executive vice president of Cypress, said that "We're four to five years away from the point at which solar is cost-effective with traditional electricity generation without any subsidy."

    SunPower has a higher conversion efficiency of 20%, the highest in the industry and doesn't see much improvement in that, rather sees cost savings coming from increasing production efficiencies.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    no the article was about them not performing well.
  • System2
    System2 Posts: 6,290 admin
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    Here is what they wrote.  I don't want to talk down anyones product, but the issue with the procurement of modules WITH inverter is a little worrisome.

    When customers buy modules made of cells with world record-breaking efficiencies, they expect record level yields in return. But when the cells don‘t meet expectations — as has been the case recently with PV systems using high-power cells from California headquartered company SunPower Corporation — people quickly begin to suspect that reports of world records are not as reliable as one might think. In this unusual case, those suspicions are unfounded. The truth is, these cells are just too good. And there‘s a little trick to reverse that effect.
    The A-300 solar cells from SunPower Corporation arc currently the world‘s record holder when it comes to efficiency for serially rnanufactured products. The average efficiency, which is more than 21
    percent, is achieved through a combination of extremely pure silicon and a very clever cell design.
    But now it appears that the cells are actually too good. The cell‘s front side is so well insulated from the contacts on the backside that the static charges on the front side accumulate. SunPower calls this effect Surface Polarization. When a module
    exposed to the sun over the
    course of a few weeks, a very
    powerful charge develops on the front side. This, combined with the cell‘s upper side being covered by encapsulation material, creates an interconnected transistor. The free electrons, which are usually
    used for electricity production and therefore improve efficiency, are forced into a short circuit (the charge carriers recombine at the front surface) and thus cannot be used for electricity production— in effect the output current of the cell is reduced. The manufacturer has been able to quantify this phenomenon. During experiments with a test System using grounded modules with voltage of more than 160 V, module power dropped from an initial 200 W to 140W.
    Apparently, this effect can be completely reversed by briefly running the modules with powers reduced by polarization at around -1,000 V against ground. This eliminates the charge on the cell‘s front side completely, and the modules recover their original power.
    Obviously, this process is not practical for Systems operating on a continuous basis, so SunPower has come up with an even simpler solution. The solar generator‘s positive pole must be grounded using a high-ohmic resistor. Not only does this completely eliminate the effect, but it actually increases cell efficiency slightly. It remains to be seen what ramifications this new discovery will have on future System planning.
    Until then, a number of problems persist with regard to what type of inverter should be used. One cannot simply employ any transformerless inverter for use with a high-ohmic ground on the generator‘s positive pole, because transformerless inverters also create a potential against ground at the solar generator. In this case, prior to combining modules and inverters, customers should contact both SunPower and the inverter manufacturer.
    In North America SunPower is exclusively selling its modules together with a positive-ground inverter using a transformer made by PV Powered.  Although inverters using transformers generally don‘t have this problem, it needs to be tested whether the generator‘s high-resistance connection with the ground potential is being incorrectly detected as an insulation error by the insulation monitor.
    However, in the long term, SunPower intends to entirely eliminate this problem by altering the encapsulation material, or even by changing the cell production
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Neat Solar cells: where on earth do you get them ( in small quantities)

    alana,
    i thank you for that as i and at least one other werevery interested in what gives with this company. as to the article itself, if the magazine objects to its reprinting here we will be happy to delete it.