ISO/TC 180/SC 1 - Climate - Measurement and data

This document gives recommended practice for the use of pyranometers in solar energy applications (e.g. testing of solar photovoltaic panels, solar thermal collectors or other devices, and performance monitoring of solar energy systems). It is applicable for both outdoor and indoor use of pyranometers, when measuring plane of array, global horizontal and reflected irradiance, or radiation from a solar simulator. The measurement may be carried out on either a horizontal or an inclined surface, and the pyranometer may be part of a diffusometer, i.e. combined with a sun-shading device to measure diffuse radiation.

This document establishes a classification and specification of instruments for the measurement of hemispherical solar and direct solar radiation integrated over the spectral range from approximately 0,3 μm to about 3 μm to 4 μm. Instruments for the measurement of hemispherical solar radiation and direct solar radiation are classified according to the results obtained from indoor or outdoor performance tests. This document does not specify the test procedures.

Its use is mandatory for the calibration of secondary standard pyranometers according to ISO 9060, and is recommended for the calibration of pyranometers which are used as reference instruments in comparisons. Is intended for use by test institutions or test laboratories equipped with well-maintained pyrheliometers and is applicable to all pyranometers. The object is to promote the uniform application of reliable methods to calibrate pyranometers, since accurate calibration factors are the basis of accurate hemispherical solar radiation data which are needed for solar energy test applications or simulations.

Provides an appropriate standard spectral irradiance distribution to be used in determining relative performance of solar thermal, photovoltaic, and other system components and materials where the direct and hemispherical irradiance component is desired. The tables presented define an air mass 1,5 solar spectral irradiance for the direct normal radiation - 5,8° field-of-view angle - and hemispherical radiation on an equator-facing, 37° tilted plane for an albedo of 0,2. These tables are intended to represent ideal clear sky conditions.

Specifies two preferred methods: the outdoor calibration (with the pyranometer in a horizontal position, in a tilted position, or at normal incidence) and the indoor calibration (using an integrating sphere with shaded or unshaded lamp, or at normal incidence). Applicable to most types of field pyranometers regardless of the type of radiation receptor employed.

Establishes a classification and specification of instruments for the measurement of hemispherical solar and direct solar radiation integrated over the spectral range from 0,3 µm to 3 µm.