Real-time estimation of global tilted irradiance using a multi-directional pyranometer: a 1-min hybrid decomposition–transposition framework

초록

Accurate global tilted irradiance (GTI) estimation is important for real-time solar-energy applications, but its performance depends on the accuracy of both irradiance decomposition and transposition. This study proposes a 1-min hybrid decomposition–transposition framework that uses ground-level multi-directional global irradiance measurements to improve GTI estimation. The proposed framework uses a multi-directional pyranometer array consisting of five global pyranometers installed on the horizontal plane and on east-, west-, south-, and north-facing vertical planes. In the decomposition, a previously developed multi-directional-irradiance-based DNI estimation method is applied, and this study incorporates a directional data augmentation to reduce its latitude dependence. DHI is subsequently calculated from the horizontal irradiance balance. In the transposition, the Perez sky model structure is used as the basis for GTI calculation, while its circumsolar and horizon brightening coefficients, F1 and F2, are inversely estimated using the decomposed irradiance components and opposite-facing directional irradiance measurements. The framework was evaluated using 1-min measurements collected in 2018 at the Solar Radiation Research Laboratory (SRRL), after quality-control procedures. For a south-facing surface tilted at 40°, the framework showed coefficient of determination (R2), root mean square error (RMSE), normalized RMSE (nRMSE), and expanded uncertainty at the 95% confidence level (U95) values of 0.996, 23.8 W/m2, 4.7%, and 13.0%, respectively. Under the same condition, the single-sensor decomposition–transposition model chains showed RMSE values of 35.5–41.2 W/m2, corresponding to a 33.0–42.2% reduction. These results suggest that multi-directional irradiance measurements can enhance minute-resolution GTI estimation and support real-time solar-energy applications requiring component-resolved irradiance information. Copyright © 2026. Published by Elsevier Ltd.

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