System for simultaneously calibrating two or more solar radiation measuring pyranometers

Abstract

System for calibrate two or more pyranometers that measure solar radiation, comprising an electronic data processor configured for generating a mean calibration constant of the pyranometers, by carrying out the steps of: installing a reference pyrheliometer with known calibration constant RDIR placed proximal to the pyranometers to be calibrated; acquiring measurements of direct normal irradiance; recording the average values VDIR×CZA, VDIF(i) with i = 1, ..., NDIF and VGBL(j) with j = 1, ..., NGBL at a same and synchronized averaging rate; fit a linear function in the form Y = M×X + B to the data points defined by X(i,j)_k = VDIF(i)_k/VGBL(j)_k and Y(i,j)_k = VDIR×CZA_k/VGBL(j)_k with k = 1,...,NREC; calculating a calibration constants of the i-th pyranometer measuring diffuse irradiance through RDIF(i,j) = -RDIR/M and of the j-th pyranometer measuring the global irradiance (1b) through RGBL(j,i) = RDIR/B; calculating a mean calibration constant for the i-th pyranometer measuring diffuse irradiance through RDIF(i) = (1/NGBL)×sum_j=1^NGBL (RDIF(I, j)), and a mean calibration constant for the j-th pyranometer measuring global irradiance through RGBL(j) = (1/NDIF)×sum_i=1^NDIF (RGBL(j,i)).