Multi-Factorial Comparison for 24 Distinct Transposition Models for Inclined Surface Solar Irradiance Computation in the State of Palestine: A Case Study

Solar energy industries require an accurate estimation of global solar irradiation particularly on inclined planes. This improves the accuracy of the sizing procedures and optimizes the performance of the solar energy platforms as photovoltaic modules and flat-plate solar collectors. A variety of the transposition models have been developed and reportedly determine incidences of solar irradiance on an inclined surface. However, there is a gap in the literature regarding identifying the most promising transposition model, particularly for the Middle East and North Africa region (MENA). Therefore, this article serves two main objectives. Firstly, it compares comprehensively 24 different transposition models. Several statistical methods are used to quantify the performance of the tilted surface transposition models. Furthermore, the transposition models are compared with real, hourly measured time-series data for several Palestinian cities to identify the promising and most accurate model. The analysis was carried out on three bases: annually, monthly, and a clearness index. The transposition models prove their ability to represent the measured data during the annual and monthly analyses, but they all failed to achieve complacency in the clearness index (KtKt) for the clear sky condition (Kt > 0.78). Secondly, the article advises a reliable and accurate transposition model for the area of the MENA for clear sky conditions. The proposed model was tested for the sites under investigation, and it produces significantly better performance than the candidate transposition models.