(Symbol: G) (Unit: W ´ m–2)
electromagnetic radiated power per unit of area
NOTE 1 Irradiance commonly references light from the sunsolar simulator
a) diffuse irradiance
irradiance excluding that portion which contributes to direct irradiance
b) direct irradiance
irradiance from the sun's disk and from the circumsolar region of the sky within a subtended angle of 8,7 ´ 10–2 radian (5°)
c) global irradiance
irradiance on a horizontal surface
NOTE 2 Global irradiance equals horizontal direct irradiance plus horizontal diffuse irradiance
d) in-plane irradiance
(Symbol: GI)
total irradiance on the plane of a PV device
e) integrated irradiance
continuously integrated spectral irradiance over the total range of wavelengths
NOTE 3 If the spectral range is limited, the range is to be stated. If not, then the irradiance is integrated over the total or almost total range of wavelengths
NOTE 4 Integrated irradiance is measured by a pyranometer that can precisely respond to the spectral profile of the radiation
f) plane of array irradiance
same as in-plane irradiance
g) spectral irradiance
(Symbol: El) (Unit: W ´ m–2 ´ µm–1)
irradiance per unit bandwidth at a particular wavelength
h) spectral photon irradiance
(Symbol: Epl) (Unit: cm–2 ´ s–1 ´ µm–1)
photon flux density at a particular wavelength Epl = 5,035 ´ 1014 ´ l ´ El, where l is in µm
i) test irradiance
(Symbol: Gt)
irradiance used for test purposes, as measured with a reference PV device
j) total irradiance
(Symbol: GT)
direct plus diffuse irradiance on an inclined surface |