Thermodynamic analysis of inlet air pre-cooling techniques of compressor is among the methods for the enhancement of gas turbine performance. This study compared the effect of using evaporative cooling system pre-cooling method, vapour compression refrigeration precooling and vapour absorption refrigeration precooling techniques to the gas turbine Net Power Output, Thermal efficiency, Thermal Efficiency Change factor (TEC) and Power Gain Ratio (PGR) taking into recognition the prevalent weather and climatic conditions of Nigeria and as well as optimization parameters for the reference system (i.e. without precooling techniques). The results show that at air temperature of 311K, the reference system, evaporative precooling, vapour compression refrigeration and vapour absorption refrigeration precooling methods recorded Net power Outputs of 23.143MW, 25.39MW, 31.84MW and 34.90MW respectively. The Thermal Efficiency Change factor recorded by the precooling systems at an ambient temperature of 311K is 8.68%, 37.4% and 51% respectively.