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Title: NREL Pyrheliometer Comparisons: September 26-October 7, 2016 (NPC-2016)

Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for developing and deploying solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations that are traceable to an international standard is the first step in producing research-quality solar irradiance measurements. National Renewable Energy Laboratory (NREL) pyrheliometer comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owners and operators, each NPC provides an opportunity to determine the unique World Radiometric Reference transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the WRR. NPC-2016 was September 26 through October 7, 2016. Participants operated 45 absolute cavity radiometers and 27 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky, direct normal solar irradiance during this period.
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  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Technical Report
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy/Solar Energy Technologies Program; USDOE Environmental Research/Atmospheric Radiation Measurement Program; NREL's Quality Management Systems & Assurance center (QMS&A)
Country of Publication:
United States
14 SOLAR ENERGY; 47 OTHER INSTRUMENTATION; NREL; National Renewable Energy Laboratory (NREL); pyrheliometer comparisons; pyrheliometer; absolute cavity radiometers; WRR; traceability; solar irradiance