Watts per Squre Ft

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Philip C
Philip C Solar Expert Posts: 45
What modules out there have the highest watt/ft^2 ?
I know Sanyo and SunPower are among the best, but after that I'm not sure

Thanks,
Philip

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,477 admin
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    Re: Watts per Squre Ft

    Mono-Crystalline
    Poly-Crystalline (slightly less eff)
    Amorphous (almost 1/2 as efficient as M/P Crystalline)

    Remember that panels are rated at their actual (lab test) output--so differences in efficiency does not affect actual output (some claim better high temperature performance or better shaded performance).

    Efficiency is simply higher eff. panels require less sq.ft / sq.meter of roof space for same power output.

    Always look at the $$$ / watt pricing to see if the panels are cost competitive for your application.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
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    Re: Watts per Squre Ft

    The Sanyo HIT technology must be at the top of the list, it's a mono panel sandwiched in layers of amorphous thin film. Sometimes called Hybrid panels. ...but then there are other hybrid panels which aren't that efficient e.g. the new Kaneka 110.

    So list would be:
    1. Sanyo HIT
    2. Mono
    3. Poli
    4. Thin film: CdTe (e.g. FirstSolar)
    5. Thin film: Amorphous silicon (a-Si)
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,780 ✭✭✭✭✭✭
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    Re: Watts per Squre Ft
    Philip C wrote: »
    What modules out there have the highest watt/ft^2 ?
    I know Sanyo and SunPower are among the best, but after that I'm not sure

    Thanks,
    Philip

    I think you have it nailed! The sunpower are hard to buy unless you are a dealer! The bifacial sanyo's have to be the most beautiful panel I have ever seen. They make you want to build all kinds of palapa's, pergolas, and awnings.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
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    Re: Watts per Squre Ft

    You have to be sure you are comparing apples to apples also.

    Standard insolation is 1024 watts/square meter. Roughly, there are 10 square feet per sq/m. So max output of a panel will be 102 watts per square foot x the eifficiency, which for most panels (not cells) is in the 12 to 18% range. Cell efficiency does not = panel efficiency.

    While the Sanyo HIT is the most efficient, it is also - by far - the most expensive, so the price of "watts per square foot" in most cases would be offset by the lower cost of using less efficient panels.
  • solarix
    solarix Solar Expert Posts: 713 ✭✭
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    Re: Watts per Squre Ft

    I've got lot of "solar coleagues" around here that sell SunPower and hear all the time how they are so great cause of the high efficiency. Always have to teach customers that what they really want is cost efficiency not space efficiency. I also contend that the higher efficiency type modules will lose productivity over time faster than the polycrystaline types. Not sure if this is true though - any body know if there is a difference in the long term ability to maintain efficiency? I figure that the higher efficiency is achieved though more rigorous processes to get perfect mono-crystaline cells and is more likely to degrade than a polycrystaline cell that starts out already degraded.
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,780 ✭✭✭✭✭✭
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    Re: Watts per Squre Ft

    Space efficiency on a pole mount or where reducing wind loading is very important can be an issue. It is a tool in the toolbox of the designer! The Sunpower modules exceed the Sanyo's by a few percent. Cost efficiency is always desirable but in some applications it is not at the top of the list. One can go up on a mountain or out to sea and get very good first hand knowledge of the issues.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,780 ✭✭✭✭✭✭
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    Re: Watts per Squre Ft
    solarix wrote: »
    I've got lot of "solar coleagues" around here that sell SunPower and hear all the time how they are so great cause of the high efficiency. Always have to teach customers that what they really want is cost efficiency not space efficiency. I also contend that the higher efficiency type modules will lose productivity over time faster than the polycrystaline types. Not sure if this is true though - any body know if there is a difference in the long term ability to maintain efficiency? I figure that the higher efficiency is achieved though more rigorous processes to get perfect mono-crystaline cells and is more likely to degrade than a polycrystaline cell that starts out already degraded.

    Boeing who bought Spectralabs has had "blended layers" since the 1950's with panel efficiencies way above Sanyo or Sunpower. Most are out in space and they hold up very well. I would not worry about them degrading! As long as there is a big company behind the warranty like BP.

    OK, maybe you should diversify the panel manufactures like stock portfolios!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net