Solar Energy

This Technical Report gives recommended practice for the use of field pyranometers in solar energy applications (e.g. testing of solar collectors or other devices, and monitoring of solar systems). It is applicable for both indoor and outdoor use of pyranometers, when measuring global and reflected solar radiation, or radiation from a solar simulator. The measurements may be carried out on either a horizontal or an inclined surface, and the pyranometer may be combined with a sun-shading device to measure diffuse radiation.

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.

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.

This International Standard gives requirements for the classification and testing of rubbers used to seal solar energy collectors in order to aid selection for specific applications. Particular rubber applications, when specified, may necessitate other requirements that take precedence over these requirements. The design requirements in this International Standard pertain only to permissible deflection of the rubber during thermal expansion or retraction of the seal in use and to the tolerances on dimensions of moulded and extruded seals.  This International Standard does not include requirements pertaining to geometrical design, fabrication or installation of the seals. This International Standard is applicable in conjunction with long-term ageing and weathering tests. However, if long-term tests are performed, it is recommended that ISO 4892-2 be complied with for ageing tests and ISO 877 for accelerated weathering tests and material exposure tests, respectively. The environmental conditions, test specimen configuration and any test deviations should be agreed upon between the parties involved. Also, if long-term tests are performed, the specific tests described in this International Standard should be performed before and after long-term testing is carried out.

This International Standard defines basic terms relating to solar energy. In addition to terms and definitions used in two of the three official ISO languages (English, French and Russian), this International Standard gives the equivalent terms and definitions in the German language; these are published under the responsibility of the member body for Germany (DIN). However, only the terms and definitions given in the official languages can be considered as ISO terms and definitions.

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.

This International Standard is one of a series of International Standards specifying methods and instruments for the measurement of solar radiation. Pyrheliometers are used to measure direct solar irradiance. The data collected are used for — the determination of the efficiency of concentrating collectors, — the determination of the direct beam resource for concentrating solar energy devices as well as for determining their siting, sizing, etc., and — the accurate determination of hemispherical solar radiation as a sum of the measured direct solar and diffuse solar radiation. The calibration hierarchy of pyrheliometers specified in this International Standard follows the scheme developed by the World Meteorological Organization (WMO) [1], and the classification and specification used are prescribed in ISO 9060. During the elaboration of this International Standard, extensive reference was made to ASTM 816-81 [2].