ECN publication
Comparison between large reference cell calibrated by ESTI-JRC, NREL and PTB, performed at ECN
Heide, A.S.H. van der; Winter, S.; Emery, K.; Zaaiman, W.
Published by: Publication date:
ECN Solar Energy 1-6-2005
ECN report number: Document type:
ECN-RX--05-004 Conference Paper
Number of pages: Full text:
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Presented at: 20th European Photovoltaic Solar Energy Conference and Exhibition, Barcelona, Spain, 6-10 juni 2005.


Calibrations of large area reference cells performed at ESTI-JRC, NREL and PTB were compared at ECN. The cells that constitute the so-called World Photovoltaic Scale (WPVS) are only 4 cm2 in size. In this study for the first time large area cells (100 cm2, 156 cm2, 225 cm2) have been used for intercomparisons between the leading calibration institutes. The short circuit current calibrations at ESTI-JRC and NREL were performed in a solar simulator, including a spectral mismatch correction. PTB uses absolute spectral responsivity curves at different bias levels for calibration. For the calibration comparison at ECN a 156 cm2 cell calibrated at NREL was used as a reference to determine the (mismatch corrected) short-circuit currents for all other cells in the ECN solar simulator. The differences between specified calibrated short circuit currents and measurements at ECN were found to be <1% for 156 cm2 cells. The largest deviation for all cells, after correction for beam non-uniformity was found to be 1.3%, for a 225 cm2 cell. The conclusion is that the variation of calibrations performed by the three calibration institutes for cells upto 225 cm2 is within 2% error margin that is specified for the small WPVS cells.

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