An existing PV system is cooled by heat dissipation to air by straight fins arrays attached at the backside of the panels. However, a little average temperature drop has been achieved in the plant. The current research aims to simulate and investigate the low cooling performance experienced in the plant and recommend improved PV cooling by backside installed fins. A CAD model was constructed with CATIA software and imported to ANSYS-Fluent to simulate and investigate the cause of low cooling performance. In addition, cooling performance by 45, 90and 135have been studied. The solar PV panel has 1000-mm-width and 2000-mm-length, whereas the fins' base dimensions are 830-mmwidth, and 1260-mm-length and each fin has 80-mm-height. The reference case study's average temperature measured in the actual site is 46.9C, while the simulation prediction is 48.4C. The 3.3 difference suggests that the simulation procedure is sufficient to investigate the other cases. Solar PV is paired with the fins air cooling system, stimulating the PV/T with only a 2.7 difference between the actual measurements and the simulation prediction. The bare panel simulation results predicted the backside temperature to be 13.4C above the ambient temperature. The 45and 90oriented fins reduced the backside temperature to 4.2C and 9.54C above the ambient temperature. In contrast, the 135 oriented fins have a negative cooling effect, as they increased the backside temperature to 19.05C above the ambient temperature. The analysis suggests that the low-performing cooling in the physical system is due to the bad thermal contact between the array base plate and the panel's backside. © 2023 WITPress. All rights reserved.