Comparison and Analysis of Instruments Measuring Plane of Array Irradiance for One-Axis Tracking PV Systems

Worldwide evaluation and correction of irradiance measurements from personal weather stations under all-sky conditions

“…There are a number of factors influencing the response of silicon-photodiode devices, such as: (i) angle of incidence, (ii) device temperature, (iii) tilt orientation, (iv) mechanical and optical asymmetries in the instrument, (v) irradiance magnitude, and (vi) spectral response (King and Myers, 1997). The difference in G readings between silicon-photodiode and thermopile pyranometers falls within ±5% when devices are correctly calibrated and maintained, and the data corrected (Al-Rasheedi et al, 2018;King and Myers, 1997;Sengupta et al, 2012;Vignola et al, 2017;Walter-Shea et al, 2019). Without corrections, the differences can reach ±15% (King et al, 1998).…”

“…The uncertainty of measurements produced by silicon-photodiode sensors has been a topic of research interest, mainly due to the low-cost solution these sensors offer for land-based measurements. A number of empirical methods have been proposed in the literature to estimate the broadband solar irradiance captured by silicon-photodiode sensors addressing effects related to temperature, spectral mismatch and solar angle of incidence (Augustyn et al, 2004;King et al, 1998;King and Myers, 1997;Vignola et al, 2017;Walter-Shea et al, 2019).…”

“…Existing empirical methods in the literature utilise solar zenith angle to compensate the spectral mismatch and cosine response effects, e.g. (King et al, 1998;King and Myers, 1997;Vignola et al, 2017;Walter-Shea et al, 2019). Using the solar zenith angle, Augustyn et al (2004) proposed a piece-wise, segmented function to compensate the so-called cat ears' effect at high solar zenith angles.…”

“…Using the solar zenith angle, Augustyn et al (2004) proposed a piece-wise, segmented function to compensate the so-called cat ears' effect at high solar zenith angles. The method developed by King et al (1998) is used as reference for the calibration methods by Augustyn et al (2004); Vignola et al (2017), which add or change parameters. Although the calibration methods mentioned were produced using a LICOR LI-200 pyranometer, the methods can be applicable to other silicon-based pyranometers using Eq.…”

“…Although Sengupta et al (2012) concluded that uncertainties in the measurements of silicon-based devices cannot be easily quantified, empirical correction procedures have been proposed based on the absolute air mass, the solar zenith angle and the temperature of the device (King et al, 1998;King and Myers, 1997;Vignola et al, 2017;Walter-Shea et al, 2019). Such empirical models require sensor-specific data that may not be readily available for generic PWS.…”