Gas turbines play an important role in supplying power for the country especially in peak electricity load. The main disadvantages are the turbines, they produce large changes are a result of climate change. However, in times of peak electricity grid and at the same time warm months, can produce gas turbines under the effect of ambient temperature, the amount of reduced considerably. The methods adopted for the turbine compressor inlet air cooling and recovery of their power optimization is necessary. In this paper, different methods of cooling the inlet air to gas turbines for Fars power plants weather conditions and eventually introduced various schemes to install combined cycle gas turbine inlet air cooling system of the plant, good design, Media evaporative air cooler system have been selected according to technical and economic evaluation. Media evaporative air cooler by an external contractor blueprint designed, constructed and installed in the plant. Performance tests are conducted at the site, 11 MW equivalent to 14.5 percent for gas units and 1.2 MW (6.2%) for steam combined cycle unit to the circuit after the Media cooling system in the summer show.