Generation of typical solar radiation year based on sunshine duration and cloud cover in South Korea

This paper discusses the possibility of using sunshine duration and cloud cover data instead of global solar radiation data in order to develop a typical solar radiation year (TSRY) for localities with abundant data on sunshine duration and cloud cover. The estimation of typical solar radiation is very important for calculations in many different solar applications. However, solar radiation measurements are not easy to obtain because of the expensive measuring equipment and techniques required. Accordingly, in six locations in South Korea where global radiation is currently measured, the global radiation was calculated using Sunshine Fraction Radiation Model (SFRM) and Cloud Cover Radiation Model (CRM), compared and analyzed. Data for Ulsan, where solar radiation is not currently measured, can be calculated by using the estimate coefficient (a, b, A, B, C and D) of the six other regions. The TSRY for the six regions located in South Korea was calculated by the SFRM and the CRM and using the Finkelsten-Schafer statistical method and compared to results generated from daily global solar radiation measured over the last twenty years. Agreement was found between the short-term data calculated on a monthly basis and the long-term data. This study recommends the use of sunshine duration and cloud cover based irradiation models if measured solar radiation data is not available. It is expected that these calculations of the typical solar radiation year will be useful to the designers of solar energy systems as well as those who need Global Hourly Solar Irradiation (GHSI) data for South Korea.