ISO 9060:2018 太陽エネルギー—半球太陽および直達日射を測定するための機器の仕様と分類 | ページ 6

3.1

hemispherical solar radiation

solar radiation received by a plane surface from a solid angle of 2π sr

Note 1 to entry: Approximately 97 % to 99 % of the hemispherical solar radiation incident at the Earth’s surface is contained within the wavelength range from 0,3 μm to 3 μm^[1]. Generally, hemispherical solar radiation is composed of direct solar radiation and diffuse solar radiation (solar radiation scattered in the atmosphere) as well as solar radiation reflected by the ground.

3.2

global horizontal irradiance

hemispherical solar radiation received by a horizontal plane surface

Note 1 to entry: The tilt angle and the azimuth of the receiver surface should be specified, e.g. horizontal.

3.3

direct solar radiation

radiation received from a small solid angle centred on the sun’s disc, on a given plane

3.4

diffuse solar radiation

diffuse radiation

hemispherical solar radiation minus coplanar direct solar radiation

Note 1 to entry: For the purposes of solar energy technology, diffuse radiation includes solar radiation scattered in the atmosphere as well as solar radiation reflected by the ground, depending on the inclination of the receiver surface.

Note 2 to entry: The tilt angle and the azimuth of the receiver surface should be specified, e.g. horizontal.

3.5

pyranometer

radiometer designed for measuring the irradiance on a plane receiver surface which results from the radiant fluxes incident from the hemisphere above within the wavelength range from approximately 0,3 µm to about 3 µm to 4 µm

Note 1 to entry: The spectral range (50 % transmittance points) given is only nominal. Depending on the radiometer design, the spectral limits of its responsivity can be different from the limits mentioned above.

3.6

pyrheliometer

radiometer designed for measuring the irradiance which results from the solar radiant flux from a well-defined solid angle the axis of which is perpendicular to the plane receiver surface

Note 1 to entry: It follows from this definition that pyrheliometers are used to measure direct solar radiation at normal incidence. Typical opening half angles of common and historical pyrheliometers range from 2,5° to 7,5°. Reference [3] recommends that the opening half-angle is 2,5° (6 10⁻³ sr) and the slope angle 1° for all new designs of direct solar radiation instruments. The opening half-angle is measured from the centre of the (circular) receiver aperture to the edge of the view-limiting aperture. The slope angle is the opening half-angle of the cone defined by both apertures. For mathematical definitions of the angles, see 5.1 b). A more detailed description of the influence of circumsolar radiation on the pyrheliometers can be found in Reference [2].

Note 2 to entry: The spectral responsivity of field pyrheliometers is often limited to the range of approximately 0,3 µm to 3 µm, depending on the radiometer properties. The spectral range (50 % points) given is only nominal. Depending on the radiometer design, the spectral limits of its responsivity can be different from the limits mentioned above.

3.7

diffusometer

radiometer designed for measuring the diffuse solar radiation, consisting of a pyranometer and a shading structure which can be a shading ball, a shading disk, a shading ring, a rotating shadowband or a shading mask

Note 1 to entry: Shading balls and disks shall be tracked to the sun, so that the pyranometer is shaded. Shading disks and their tracking are defined in ISO 9846 ^[4]. The centre of a shading ball is tracked to the same point as the centre of a shading disk. The diameter of the ball corresponds to the diameter of the disk. The shaded opening angle and slope angle of shading balls and ‐disks for the sun in the zenith shall be 2,5° and 1°.

Note 2 to entry: Shading rings are positioned such that the pyranometer is shaded for all solar positions occurring throughout approximately two days. Shading rings shall be adjusted approximately every two days. Shading rings therefore prevent not only the direct radiation, but also a part of the diffuse radiation from reaching the pyranometer and only an approximation of the diffuse radiation can be measured.

Note 3 to entry: A rotating shadowband is rotated around the pyranometer so that this pyranometer is shaded for some time during the rotation. The pyranometer measures an approximation of the diffuse radiation when the shadowband shades the sensor. The pyranometer measures the hemispherical radiation when the shadowband is below the pyranometer’s field-of-view. When the shadowband’s shadow is close to the sensor, but not on the sensor the hemispherical radiation except of the blocked diffuse radiation is measured. With these three measurements so-called rotating shadowband irradiometers determine the diffuse radiation.

Note 4 to entry: Shading masks throw a shadow on one or various pyranometers depending on the solar position.

3.8

offset correction

value added algebraically to the uncorrected result of a measurement to compensate for systematic error

Note 1 to entry: The offset correction is equal to the negative of the estimated systematic error.

Note 2 to entry: Since the systematic error cannot be known perfectly, the compensation cannot be complete.

3.9

correction factor

numerical factor by which the uncorrected result of a measurement is multiplied to compensate for systematic error

Note 1 to entry: Since the systematic error cannot be known perfectly, the compensation cannot be complete.

[SOURCE: ISO/IEC Guide 98‑3:2008, B.2.24]

3.10

acceptance interval

3.11

tolerance interval

3.12

guard band

3.13

accuracy class

class of measuring instruments or measuring systems that meet stated metrological requirements that are intended to keep measurement errors or instrumental uncertainties within specified limits under specified operating conditions

[SOURCE: ISO/IEC Guide 99:2007, 4.25, modified — Notes have been deleted.]