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Encontro de Energia no Meio Rural
Abstract
RECIERI, Reinaldo Prandini, QUALLIO, Silvana, FERRUZZI, Yuri et al. Models in the estimate of the diffuse solar radiation. In Procedings of the 5th Encontro de Energia no Meio Rural, 2004, Campinas (SP) [online]. 2004 [cited 04 November 2024]. Available from: <http://www.proceedings.scielo.br/scielo.php?script=sci_arttext&pid=MSC0000000022004000200022&lng=en&nrm=iso> .
In this work we evaluate, by means of polynomial regression analysis, several models that relate the diffuse fraction of the global radiation (Kd) with the clearness index (Kt). The experiment was conducted in the Solar Radiometry Station of Cascavel/PR from the first of January to the 31st of December, in the year of 2001. The solar radiation components were monitored by the following manufactured instruments: Pyranometer (KIPP&ZONEN (CM3) and pirheliometer (EPPLEY NIP) connected in a sun tracker (ST-1 model). A datalogger CR10X from the CAMPBELL SCIENTIFIC was used in the data acquisition. This datalogger was programmed in the frequency of 1 Hz storing an average of 5 minutes of collected data. Among the equations the best values of RMSE an MBE were find in the 4th and 3rd degrees, respectively. We also find that the 4th degree polynomial equation ( Kd=1,172-1,001Kt+3,992Kt2-11,742K t3+7,698Kt4) generalizes the utilization of equations for diffuse solar radiation estimation. This means that this equation probably can be applied for any place and climatic conditions.
Keywords : Radiação solar difusa; Modelo de estimativa; índice de claridade.