Global Solar Radiation Analysis of the Modified Savin-Angström Method by using Pyranometers CMP 6 and CMP 11

Solar energy is one of the most available energy sources and the most ecological one. Currently, the firm Kipp & Zonen belongs to prominent producer of sensors for measuring global radiation. These sensors are the most used ones in our country and also in network of meteorological measurements of WMO. Therefore, the two types of measuring sensors for global radiation (pyranometer PMP 11, CMP 6) in comparison with the calculation method Savin-Angstrom are analysed. By processing the experimental measurements of global radiation in locality Nitra, there can be observed differences between standard CMP 11 and CMP 6. The measured values by CMP 6 pyranometer in comparison with secondary standard CMP 11 are lower by about 21% to what corresponds to the accuracy level (First Class) of sensor CMP 6. Differences may have been caused by higher aberrance of non-linearity, aberrance at sunrise and sunset i.e. directional errors and also by the fact that sensor CMP 6 is not equipped with integrated temperature compensation. The similar situation was also in the comparison of global radiation, which was calculated according to the modified Savin-Angstrom method and CMP 11. Notional differences were 7% compared with the measured values of CMP 11 standard.