Calibration procedure of Hukseflux SR25 to Establish the Diffuse Reference for the Outdoor Broadband Radiometer Calibration

Technical Report · Tue Aug 01 00:00:00 EDT 2017

DOI:https://doi.org/10.2172/1378901· OSTI ID:1378901

Reda, Ibrahim M. ^[1]; Andreas, Afshin M. ^[1]

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1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Accurate pyranometer calibrations, traceable to internationally recognized standards, are critical for solar irradiance measurements. One calibration method is the component summation method, where the pyranometers are calibrated outdoors under clear sky conditions, and the reference global solar irradiance is calculated as the sum of two reference components, the diffuse horizontal and subtended beam solar irradiances. The beam component is measured with pyrheliometers traceable to the World Radiometric Reference, while there is no internationally recognized reference for the diffuse component. In the absence of such a reference, we present a method to consistently calibrate pyranometers for measuring the diffuse component. The method is based on using a modified shade/unshade method and a pyranometer with less than 0.5 W/m2 thermal offset. The calibration result shows that the responsivity of Hukseflux SR25 pyranometer equals 10.98 uV/(W/m2) with +/-0.86 percent uncertainty.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1378901
• Report Number(s): NREL/TP-1900-68999
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
absolute cavity radiometer
diffuse irradiance
global solar irradiance
pyranometer
pyrheliometer
zenith angle