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Does 33% efficiency means it can generate 3.3kW per m^2?!

by syntaxing 3y ago

philipkglass 3y ago
330 watts. Sunlight is about 1000 watts per square meter at noon on a clear day.
- photonerd 3y ago
  That might be easy to remember for baseline calculations but it’s actually more like 1,360 watts per square meter. So a smidge below 450W at 33%
  - philipkglass 3y ago
    That's above the Earth's atmosphere. At sea level it's about 1000 watts: https://acee.princeton.edu/wp-content/uploads/2017/09/SolarDistillate_Article3.pdf https://acee.princeton.edu/wp-content/uploads/2017/09/SolarD... The intensity of the Sun’s energy is about 30 percent greater at the top of the atmosphere, but various gases and aerosols reduce the intensity by absorbing sunlight as it travels through the atmosphere toward the Earth’s surface. Where the Earth’s surface is flat on a clear day at sea level, with the Sun directly overhead, the average intensity of direct sunlight is about 1,000 watts per square meter. Satellites have modestly better solar resources to work with since there is no atmospheric attenuation.
    - GeorgeTirebiter 3y ago
      It depends on the absorption bands used. One big downside of PV cells is they don't use energy in the blue. Perovskites do absorb blue. So a combo should do better than either alone. The average intensity of solar energy reaching the top of the atmosphere directly facing the Sun is about 1,360 watts per square meter. You get about 1,000 W per square meter at sea level https://www.solar-electric.com/learning-center/solar-insolation-maps.html/ https://www.solar-electric.com/learning-center/solar-insolat...
    - photonerd 3y ago
      At sea level it varies so much depending on local climate & atmospheric conditions—even during the same day—that it’s not really helpful for calculations. The mean global average is between 164 watts to 340 watts per square meter over a 24-hour day, for example.
  - maxbond 3y ago
    Where I live, in a desert with a rain shadow ensuring clear skies most days? Sure, in my solar design class we took out a lightmeter and measured 1200W/m^2. Maybe on a good day it could push 1300W/m^2. In many other climates, 1000 is honestly a generous estimate. (Presumably they're aware and that's why they hedged by specifying peak power).
- syntaxing 3y ago
  Ahh you’re right, for some reason my head thought it was 10 kW.

Does 33% efficiency means it can generate 3.3kW per m^2?!

philipkglass 3y ago

330 watts. Sunlight is about 1000 watts per square meter at noon on a clear day.

photonerd 3y ago
That might be easy to remember for baseline calculations but it’s actually more like 1,360 watts per square meter. So a smidge below 450W at 33%
- philipkglass 3y ago
  That's above the Earth's atmosphere. At sea level it's about 1000 watts: https://acee.princeton.edu/wp-content/uploads/2017/09/SolarDistillate_Article3.pdf https://acee.princeton.edu/wp-content/uploads/2017/09/SolarD... The intensity of the Sun’s energy is about 30 percent greater at the top of the atmosphere, but various gases and aerosols reduce the intensity by absorbing sunlight as it travels through the atmosphere toward the Earth’s surface. Where the Earth’s surface is flat on a clear day at sea level, with the Sun directly overhead, the average intensity of direct sunlight is about 1,000 watts per square meter. Satellites have modestly better solar resources to work with since there is no atmospheric attenuation.
  - GeorgeTirebiter 3y ago
    It depends on the absorption bands used. One big downside of PV cells is they don't use energy in the blue. Perovskites do absorb blue. So a combo should do better than either alone. The average intensity of solar energy reaching the top of the atmosphere directly facing the Sun is about 1,360 watts per square meter. You get about 1,000 W per square meter at sea level https://www.solar-electric.com/learning-center/solar-insolation-maps.html/ https://www.solar-electric.com/learning-center/solar-insolat...
  - photonerd 3y ago
    At sea level it varies so much depending on local climate & atmospheric conditions—even during the same day—that it’s not really helpful for calculations. The mean global average is between 164 watts to 340 watts per square meter over a 24-hour day, for example.
- maxbond 3y ago
  Where I live, in a desert with a rain shadow ensuring clear skies most days? Sure, in my solar design class we took out a lightmeter and measured 1200W/m^2. Maybe on a good day it could push 1300W/m^2. In many other climates, 1000 is honestly a generous estimate. (Presumably they're aware and that's why they hedged by specifying peak power).
syntaxing 3y ago
Ahh you’re right, for some reason my head thought it was 10 kW.