Estimation of Global Solar Radiation using Pyranometer and NILU-UV Irradiance Meter at Pokhara Valley in Nepal

Abstract

The global solar radiation (GSR) and cloud transmittance factor (cf) are measured at the horizontal surface since 2009 using calibrated CMP6 Pyranometer and NILUUV Irradiance Meter at Pokhara (28.22°N, 83.32°E) which is about 800m from the sea level lying just 20km south of the Himalayas. This paper explains the daily, monthly and seasonal variation of global solar radiation and also compared with temperature and rainfall to global solar radiation. The annual average daily global solar radiation is about 4.81 kWh/m2/day which is sufficient to promote solar active and passive solar energy technology at sub-Himalaya terrain Pokhara and other similar geographical locations. The correlation coefficient 0.70 is found in between clearness index (K) and cloud transmittance factor (cf). This novel result can be used for location of similar meteorological and geographical characteristics at which solar data are not available. DOI: http://dx.doi.org/10.3126/jie.v9i1.10672Journal of the Institute of Engineering, Vol. 9, No. 1, pp. 69–78