Solar insolation in space

littleharbor2
littleharbor2 Solar Expert Posts: 2,032 ✭✭✭✭✭
Was watching the NASA Channel last night and one segment they were talking about the solar panels they use to create electricity in  space. While they didn't mention it , it piqued my curiosity as to how much insolation they can get in the vacuum of space. In perfect and exceptional situations we can get 12-1300 watts per square meter, maybe more, on earth. Anybody know what they get in outer space?

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,404 admin
    For our calculations, we typically use 1,000 W per sq meter.

    For space:

    https://en.wikipedia.org/wiki/Solar_constant
    The actual direct solar irradiance at the top of the atmosphere fluctuates by about 6.9% during a year (from 1.412 kW/m2 in early January to 1.321 kW/m2 in early July) due to the Earth's varying distance from the Sun, and typically by much less than 0.1% from day to day.
    Remember that solar cells cannot use the "entire" spectrum, so what an actual solar panel can convert to electricity is not 100% of total actual irradiance (i.e., infra red, ultra violet, etc.).

    Example:

    https://www.researchgate.net/publication/258549615_A_comparison_of_silicon_and_germanium_Photovoltaic_Power_Conversion_for_power-over-fibre

    https://qdsolarinc.com/technology/

    The typical "best laboratory silicon panel on the the ground" is around 26.7% overall efficiency. Best commercial is something like 25%

    https://www.tandfonline.com/doi/full/10.1080/23746149.2018.1548305

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,032 ✭✭✭✭✭
    Thanks Bill. I was thinking it would be higher. Aren't they typically very cold out there?  I was wondering how much the hi tech satellites PV arrays get. I have seen some pretty impressive "Cloud Edge Effect" power on my array over the years and not even in frigid conditions.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

  • BB.
    BB. Super Moderators, Administrators Posts: 33,404 admin
    A couple of discussion links for ISS:

    https://space.stackexchange.com/questions/14256/what-is-the-temperature-of-solar-panels-used-in-space-missions-such-as-iss

    https://space.stackexchange.com/questions/23013/how-are-the-silicon-pv-cells-constructed-in-the-isss-solar-panels-are-they-as

    The first link says simulated panel temperatures run from -100F in eclipse to +150F in full sun.

    The second link has a bit more detail on cell design and construction...

    Edge of cloud effects have been described (in my humble opinion) as a lensing effect. So collection from a larger region and focusing to a a smaller area (your panel) would seem to be possible.

    It seems that the photon physics of clouds are not what one would expect. Not sure "lensing" is actually the correct theory... "Glories" would seem to be an edge of object lensing effect... However, it may not be accurate:

    https://science.howstuffworks.com/nature/climate-weather/atmospheric/cloud-spiral-phenomenon.htm



    https://www.nature.com/articles/nature.2014.14869
    Optical theorists' attempts to fully understand how glories work were unsuccessful until the 1980s, when physicist Moysés Nussenzveig at the Federal University of Rio de Janeiro in Brazil showed that the main cause is a process known as wave tunnelling2,3. This is caused when rays of sunlight reflected by a droplet do not actually hit the droplet — as in the case of rainbows — but merely pass near it. They nonetheless stir up electromagnetic waves within the droplet. Those waves rattle around inside the droplet and eventually tunnel back out, sending light rays back in the direction from which they came. The way waves resonate within the droplet is wavelength-dependent, thus splitting white light into the spectrum of colours.
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,032 ✭✭✭✭✭
    We get a lot of cool views out west of all the rocket launches from Vandenberg AFB

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,032 ✭✭✭✭✭
    I'm really surprised to see the same type cells still being used in modern day satellite PV Here's a photo from one of the linked articles and a photo of one of my vintage panels made with the same type cells. you might need to enlarge the first photo to get a good look. 

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

  • BB.
    BB. Super Moderators, Administrators Posts: 33,404 admin
    I saw that too...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset