## 4 Results and Discussion
Thus, the thermal conductivity of the metal is enhanced and the thermal conductivity increases drastically as the temperature increases (see [PERSON] [31]). Readers interested in this phenomenon should consult references [9; 31; 42; 43; 44; 45]\". Figure 2:5 Thermal energy generated by PV-Th solar panels with different solar radiations. Figure 2:6 Hybrid thermal energy efficiency generated by PV-Th solar panels with different solar radiations. Figure 2:7 Thermal storage tank thermal energy generated by PV-Th solar panels with different solar radiations. Figures 21-24 present a comparison of the key parameters in this study with the different nanofluids under investigation: Al\({}_{2}\)O\({}_{3}\), CuO, Fe\({}_{3}\)O\({}_{4}\), and SiO\({}_{2}\), at solar radiation 750 w/m\({}^{2}\) and a nanofluid concentration of 5%. It is evident from the results displayed in these figures that CuO nanofluid has the highest absorbed thermal energy dissipated from the PV-Th solar panel compared to the other nanofluids and water as a heat transport fluid, followed by Fe\({}_{3}\)O\({}_{4}\) nanofluid. In particular, Figure 22 demonstrates that better hybrid system efficiency was obtained with CuO nanofluid, followed by Fe\({}_{3}\)O\({}_{4}\), compared to the water-based fluid and other nanofluids under investigation. Additionally, it can be noted that the higher the magnetic field, the more thermal energy absorbed and dissipated to the nanofluids, and also the higher the magnetic field, the higher the hybrid system efficiency. As for the characteristics of the heat pipes, it should be pointed out that the use of the Cuo nanofluid resulted in the highest thermal energy dissipation from the heat pipe condenser section into the storage tank. In turn, the highest heat pipe efficiency was obtained with  
Figure 2:8 Heat pipe thermal energy efficiency generated by PV-Th solar panels with different solar radiations. the use of the CuO as a heat transport nanofluid. Additionally, the higher the magnetic field, the more thermal energy developed in the heat pipe condenser section and the higher the heat pipe efficiency. \"The thermal conductivity of a specific material is considered the most dominant characteristic affecting heat transport and is highly dependent on several factors. Thus, the results obtained after this investigation study demonstrated that the CuO nanofluid not only has the highest thermal conductivity but also has higher thermodynamic and thermophysical properties compared to the other nanofluids under investigation, including water as heat transport fluid. It has also been shown by other references [21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31] that the heat transfer coefficient of nanofluid becomes higher than that of pure fluid at the same Reynolds number and increases with the increasing of the mass fraction of CuO nanoparticles\". Figure 2:9 Thermal energy transferred to nanofluids from PV-Th solar panels. Figure 4:0 Thermal storage tank dynamic temperature profile generated by PV-Th solar panels with different solar radiations. \"It was reported in the literature [15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26] that the thermal conductivity of magnetorheological fluid increased with increasing magnetic field in the temperature intervals from 0 to 50 \({}^{\circ}\)C and from 50 to 100 \({}^{\circ}\)C and the direction of the magnetic field influenced the thermal conductivity. This was supported by very recently reported work [39] that found that ferrofluid additives caused a tremendous improvement in the heat transfer of the fluid. The use of the alternating magnetic field also led to an increase in the heat transfer rate, along with the spiral coil.\" The observations reported in the aforementioned studies are in agreement with others in the literature as long as the increase in the PV cell temperature was within the limitation imposed by the manufacturer. Similar observations have been made with the other nanofluid concentrations of 10% and 20% in this study.