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Encontro de Energia no Meio Rural


RECIERI, Reinaldo Prandini, DALLACORT, Rivanildo, GNOATTO, Estor et al. Eficiência do método de medida da radiação solar difusa medida por sombreamento em função do tipo de cobertura do céu. In Procedings of the 4th Encontro de Energia no Meio Rural, 2002, Campinas (SP) [online]. 2002 [cited 12 June 2024]. Available from: <http://www.proceedings.scielo.br/scielo.php?script=sci_arttext&pid=MSC0000000022002000100054&lng=en&nrm=iso> .

The work presents a comparative study among the method of measure of the diffuse solar radiation (Rd) monitored by piranometer shadowed with ring, with the standard direct method, in function of the type of covering of the sky. The diffuse radiation of reference was obtained by difference among the global radiation (RG), measured by a piranometer, and the direct radiation projected in the horizontal (RD.cosz), measured by a pirelyometer (Rd=RG-RD.cosz). In the experimental rehearsal, driven in the EXPERIMENTAL STATION AGROMETEOROLÓGIC of Cascavel/PR (lat 24º53'Sul, long 53º23'Oeste, alt. 682m), two piranometer of KIPP&ZONEN Modelo was used - CM3 with constant of calibration 18,99 mV/Wm-2 and 18,73 mV/Wm2, pirelyometer NIP coupled in a solar rastreador ST1 of EPPLEY and a sombreamento ring (f=80cm; L=10cm). it was Used in the acquisition of the data a datalogger of CAMPBELL (model CR10X), programmed to accomplish a reading a second of each channel and to store the average arithmetic of five minutes during the experimental rehearsal under conditions of open sky, partially cloudy and clouded for 1 year. The obtained medium mistakes show that the method of the sombreamento ring used in the measure of the diffuse radiation with correction of Drummond differs lathe of 8,53%, 10,32%, 8,21% and 4,75% of the pattern and Melo 9,16% model, 10,71%, 9,29% and 6,17%, without considering the type of covering of the sky, for clean sky, partially cloudy and cloudy, respectively.

Keywords : Radiação solar difusa; anel de sombreamento; cobertura do céu; piranômetro.

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