Objectives: To understand the two-phase closed thermosiphons (TPCT) which is being used nowadays to reduce heat by using thermosiphon. Methods: The experiment is carried out with different inclination angles and by calculating the heat transfer parameters (mention them) 0°,45°,90° with the heat input of 50-250w and compare with previous results. Findings: The TPCT mainly has many advantages, having the capacity of transferring a high amount of heat in a small size. Nanofluid play an important role in the aluminum oxide (Al2O3) Nanofluid is used because of high thermal conductivity and low thermal resistance, Due to the presence of this Nanofluid, the heat transfer rate in the evaporator section gets decreased and at the time of applying the highest heat flux the thermal resistance tents to be low. Novelty: Aluminum oxide (Al2O3) Nanofluid was tested in the various setting angles 0°, 45°,90°. Among these 45° have shown better performance in all the properties such as low temperature and high heat transfer rate and high thermal conductivity. So the 45° have shown better performance compared to the other two setting angles.