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: ENCONTRO DE ENERGIA NO MEIO RURAL, 5., 2004, Campinas. Proceedings online... Available from: <http://www.proceedings.scielo.br/scielo.php?script=sci_arttext&pid=MSC0000000022004000200022&lng=en&nrm=abn>. Acess on: 27 Apr. 2024.

In this work we evaluate, by means of polynomial regression analysis, several models that relate the diffuse fraction of the global radiation (K_d) with the clearness index (K_t). The experiment was conducted in the Solar Radiometry Station of Cascavel/PR from the first of January to the 31^st 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 4^th and 3^rd degrees, respectively. We also find that the 4^th degree polynomial equation ( K_d=1,172-1,001K_t+3,992K_t²-11,742K _t³+7,698K_t⁴) 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.