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IESRE Pyranometer Calibrations at the |
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Starting in the Spring of 2007, two IESRE pyranometers were sent to the National Renewable Energy Laboratory's Solar Radiation Research Laboratory at Golden, Colorado. The above images show two views of IESRE pyranometers (the small rectangular enclosures in the foreground of the righthand image) installed at SRRL's calibration facility. At this site, the performance of the highest quality research instruments for measuring solar radiation is monitored constantly. The services provided by SRRL include calibrating commercial instruments, too. The outputs from IESRE's pyranometers are recorded along with reference instruments, so they can be calibrated against reference standards.
The Figures below show some preliminary calibration data from NREL during 01-06 June, 2007. There are some small differences in how P-007 and P-008 responds to sunlight reflected from clouds or in the shadow of clouds, compared to NREL's reference pyranometers. However, when insolation is averaged over an entire day, the results agree very well -- mostly to within less than 2%.
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| Comparison of insolation averaged over a day |  |