부산대학교 도서관

Repeated testing of any construct in research is essential, as it reinforces knowledge, promotes validity and enables its successful use in other applications. The purpose of this paper is to present results of repeatedly testing the impact that three different tilt angles have on the output power of a PV module in a semi-arid region of SA, thereby contributing to absolute validity. An experimental design is used with a longitudinal study cover 2015 through 2017. These three years of results for the winter season reveal that the PV module which was set to a tilt angle of 9 + 10° produced the highest yield of output power. It can thus be recommended that PV modules be mounted at 9 + 10° for the winter time period in semi-arid regions of South Africa and that the setup and procedures used in this study are valid.