## 3 Results and Discussions
Figure 5a displays the temperature distribution measured 0.1 cm below the interface of the heated TPMS block. The distribution graph indicates that as the flow velocity increases, more heat is removed from the system during the cooling process. Additionally, an improvement in temperature homogeneity was recorded as the flow velocity increased. Moreover, the use of TPMS in a gyroid structure has a homogeneous effect on the temperature distribution. The temperature differential between thermocouples 1 and 7 remains below 1.5 \({}^{\circ}\)C, regardless of the inlet temperature. The inlet temperature range, derived from the lowest and highest flow velocities, is approximately 15 \({}^{\circ}\)C. Figure 5b depicts the difference between the block temperature and the inlet temperature, facilitating the evaluation of heat removal by the TPMS independent of the system's initial temperature. The temperature scale in the graph ensures precise verification of temperature uniformity. Figure 5b depicts the difference between the block temperature and the inlet temperature, facilitating the evaluation of heat removal by the TPMS independent of the system's initial temperature. The temperature scale in the graph ensures precise verification of temperature uniformity. As observed in Figure 5b, the homogeneity and temperature difference were calculated to be approximately 0.5 \({}^{\circ}\)C, with the temperature differential between TC1 and TC7 ranging from 0.49 \({}^{\circ}\)C to 0.51 \({}^{\circ}\)C across different flow rates, demonstrating remarkable thermal uniformity within the Al TPMS structure despite variations in flow conditions. The dimensionless temperature variable Theta (\(\theta\)), representing the experimental data, is presented in Figure 5c. The normalization of instantaneous temperature based on the difference between inlet and outlet temperatures enables \(\theta\) to facilitate comparison of results obtained under various experimental conditions. Higher \(\theta\) values indicate enhanced heat transfer rates in specific regions, demonstrating more effective thermal energy exchange between the fluid and heat exchanger surface. This phenomenon manifests as increased fluid heating or cooling, depending on the operational mode. The dimensionless temperature distribution has been employed to characterize the heat transfer process and elaborate on temperature variations within the system. The gradual progression of \(\theta\) values along the flow direction provides valuable insights into the thermal behavior and efficiency of the heat exchanger design. The dimensionless temperature distribution presented in Figure 5c reveals that the temperature profile in the investigated Al TPMS structure is uniform by eliminating the influence of inlet and outlet temperatures, indicating homogeneous heat transfer throughout the system and optimal thermal performance. Figure 4: The inlet temperature distributions of the fluid entering the test unit: (**a**) Al TPMS and distilled water, (**b**) Ag TPMS and distilled water, (**c**) Al TPMS and nanofluid, (**d**) Ag TPMS and nanofluid. To further enhance the heat transfer performance of the system, experiments were repeated using the Ag TPMS structure, which has a high thermal conductivity. The thermal conductivity of Ag is approximately 1.8 times higher, indicating that the Ag TPMS structure can conduct heat more efficiently and transfer more heat to the cooling fluid, which is water. The gyroid structure of the Ag TPMS provides a large surface area for heat transfer, allowing faster absorption of heat around the structure and more effective removal through water circulation. To evaluate the heat transfer performance of the Ag TPMS block, parameters such as temperature distribution, temperature difference, and dimensionless temperature distribution were examined in Figure 6.  
Figure 5: Al TPMS structure using distilled water: (**a**) temperature, (**b**) temperature difference, (**c**) dimensionless temperature distributions.