International Electrotechnical Commission
Glossary

ENirradiance 
(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 m–1)

irradiance per unit bandwidth at a particular wavelength

h) spectral photon irradiance

(Symbol: Epl) (Unit: cm–2 s–1 m–1)

photon flux density at a particular wavelength Epl = 5,035 1014 l El, where l is in m

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


TC/SC:82Terms     Info     Publications
Published in:IEC 61836, ed. 2.0 (2007-12) Terms     Info
Reference number:3.6.25

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