*3.1. Site and Instruments*

This study was conducted at KKU, located in Abha, Asir, Saudi Arabia. Saudi Arabia is part of the northern hemisphere, centered in West Asia. The country is divided into 13 administrative regions. Abha is the capital of the Asir region, situated 2200 m above sea level in the southwestern part of Saudi Arabia. Its coordinates are 18°13 14.40 N and 42°30 15.59 E. The solar PV system was installed on a south-facing rooftop at a tilt angle of 22° with the parking lots of the KKU campus, as shown in Figures 1 and 2. For research purposes, it was installed in November 2018 in the College of Engineering, far away from the harsh weather conditions of the marine environment. The selected parameters for the tilt and azimuth angle for the system are shown in Table 1. The parameters were selected in accordance with the actual values of the existing system.

**Table 1.** Orientation Parameters Selected In the PV System.


**Figure 1.** Geographical Location of Abha.

**Figure 2.** The Installed solar PV system at KKU.

As presented in Table 2, the solar PV system comprises 20 modules of type KS-240PC with one TRIO-5.8-TL-OUTD-400 inverter of 5.8 kW rating. The 20 modules are distributed in a total area of 33.2 m<sup>2</sup> over one string of the maximum power point tracker (MPPT) for maximum installation flexibility for optimal energy production. This inverter includes two MPPTs and integrates power control, monitoring functionalities, and environmental sensor inputs without the need for any external components. The total installed PV power is 4.80 kWp. The PV array parameters considered here have the following manufacturer parameters. The inverter's nominal ac power is 5.22 kW and the maximum ac power is 5.8 kVA, as the name indicates. The maximum efficiency is 98% at a voltage level of 175 V. The maximum efficiency is set as 97.5% according to the European efficiency, the average operating efficiency over a yearly power distribution corresponding to the middle-Europe climate. The inverter has two MPPT inputs, which make it possible to connect strings with different panels to one inverter. The nominal power of the two strings connected to the inverter is 4.6 kW ac, which fits well with the inverter's nominal power.


**Table 2.** PV Array Parameters and Characteristics.

Radiation measurements were performed by a Pyranometer (Py), as shown in Figure 3). This is a solar irradiance sensor designed to measure the global solar irradiances, which is the amount of solar energy per unit area per unit time incident on a specific orientation surface emanating from a hemispherical field of view.The global solar irradiance includes both direct and diffuse sunlight, and, in some cases, specular reflections of sunlight. Nothwithstanding this, the weather station mentioned in Section 3.2 includes a built-in Py. We observed the SR20-T2 Py to be more precise than the weather station built-in Py, where we validated our reading via the PVsyst software [35]. The Py's specifications are summarized in Table 3.



**Figure 3.** SR20-T2 Py.
