Institute of Fundamental Technological Research

Results of the twelve years measurements carried on at SGGW, of solar radiation on tilted surface oriented south, with tilt angle equal to minimum zenith angle, were analysed. Monthly values of the measured radiation were compared with those predicted using solar data of the Typical Meteorological Year for Warsaw, for three different models of the sky diffuse radiation. Anisotropic models predict higher values of radiation on a tilted surface as compared with the isotropic model, however for summer months differences are only 1-2%.

Results of the twelve years measurements carried on at SGGW, of solar radiation on tilted surface oriented south, with tilt angle equal to minimum zenith angle, are presented. Test calculations were performed, to compare results obtained with the Institute of Meteorology and Water Management hourly data for the station Warsaw - Bielany, using the isotropic model of diffuse radiation, with the SGGW measurement results. In general, good agreement is to be observed between calculated and measured daily radiation, and sunny day hourly radiation.