Solar Cell
Efficiency
Some Definitions:
Emissivity, epsilon: a unitless number between 0 and 1 which defines
howwell a surface emits radiation, also called emittance. This value can be
different for each wavelength. The tabulated values are usually averaged over
the infrared wavelengths. A perfect emitter is called a black body and has a
value of 1.
Absorptivity, alpha: also called absorptance, basically the same as
emissivity, however, the tabulated values are averaged over the solar
spectrum. The value represents how well a surface absorbs radiation.
Thermal Properties - Triple
Junction GaAs
Solar Absorptance= 0.92
Emittance (Normal)= 0.85
Efficiency / Design
-
BOL: up to 26% minimum average
efficiency (28°C, AM0)
-
EOL: up to 21% minimum average
efficiency (28°C, AM0)
Triple Junction GaAs solar cells
With an efficience of 26%, the effective* solar
absorptance would be:
a* = 0.92 - 0.26 = 0.66
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