ASTM E772-15 (R2021) pdf free download.Standard Terminology of Solar Energy Conversion.
1 .1 This terminology pertains to the conversion of solar energy into other forms of energy by various means, including thermal absorption (i.e., solar thermal) and the photovoltaic effect (i.e., photovoltaics).
1.2 This terminology also pertains to instrumentation used to measure solar radiation.
1.3 This terminology also pertains to glass for solar energy applications.
1.4 Fundamental terms associated with electromagnetic radiation that are indicates as derived units in Standard IEEE! ASTM SI 10 are not repeated in this terminology.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
3. Adjectives for Electromagnetic Radiation
3.1 Properties and quantities associated with electromagnetic radiation vary with:
3.1.1 The direction and geometric extent (solid angle) over which the incident or exitant flux, or both, is evaluated, and
3.1.2 The relative spectral distribution of the incident flux and the spectral response of the detector for exitant flux.
3.2 Adjective modifiers can be used to indicate the geometric. spectral. and polarization conditions under which radiometric properties and quantities are evaluated. The adjectives defined in this Terminology are: conical, diffuse, direct, directional, hemispherical, luminous, normal, and spectral.
3.3 For reflectance and transmittance, the direction and geometric extent of both the incident beam and exitant beam must be specified.
3.4 For emittance. only the exitant beam need be specified, and for absorptance, only the incident beam need be specified.
3.5 Radiometric properties also vary with the polarization of the incident flux and the sensitivity to polarization of the collector-detector system for flux incident or exitant at angles greater than about 15° from normal.
3.6 An instrumem used for solar energy measurements or a solar energy receiver will usually determine the directions and geometric extents, such as a pyranomeer, a pyrheliometer, or a flat-plate solar thermal collector.
4. Terminology
ELECTROMAGNETIC RADIATION AND OPTICS
absorptance, ,n—ratio of the absorbed radiant or luminous flux to the incident flux.ASTM E772 pdf download.