Menentukan Koefisien Nilai A0,A1 dan K dari Perhitungan Fraksi Radiasi Menggunakan Metode Curve Fitting

Abstract

Solar radiation is a key factor in solar energy calculations, essential for various applications, particularly in solar power generation systems. This study estimates the parameters a₀, a₁, and k used in the solar radiation fraction equation based on the zenith angle using the curve fitting method. The dataset used consists of observations over the past five years in Medan, Indonesia. Zenith angle calculations were performed using astronomical equations based on the site's latitude, solar declination, and hour angle. Non-linear regression was applied to determine the optimal parameter values for the exponential model used. The results indicate that the curve fitting model effectively represents the relationship between the solar radiation fraction and the zenith angle with high accuracy, as evidenced by a determination coefficient (R² > 0.90). Model validation with observational data shows a low error rate, making it suitable for estimating solar radiation without direct measurement. This model has strong potential for optimizing solar energy systems and advancing renewable energy research.