Gas Turbine Performance is strongly affected by ambient temperature. High temperature decreases power output, due to reduce of inlet air mass flow rate. 1C rise in ambient air temperature decreases the Gas Turbine output by 0.5%…0.9%. One of the cheapest and effective ways to recover the Gas Turbines output loss is evaporative air-cooling of Gas Turbine inlet. Gas Turbine power output can be increased by more than 10% by inlet air-cooling.