The process in a gas turbine plant involves certain losses which can be divided into internal and external losses. In term of internal losses, the main factor is changing the state of working fluid. Since the temperature of atmospheric air may vary within a wide range, its variations can influence strongly the efficiency of gas turbine plants. With growing ambient air temperature, the specific volume of air increases, which can result in a larger work spent for air compression in the compressor. One of the most effective method for increasing the efficiency of gas turbine plants is to raise the gas temperature before the turbine. Since this temperature is the highest temperature in the cycle, this method is applicable for gas turbine plants of any scheme and type. However, there are some limitations on increasing gas temperature. The allowable temperature for reliable operation is between 1000 and 1400 k. However, decreasing ambient air temperature to increase the efficiency of gas turbine plants is easier and at low costs compared to rising gas temperature. As a decrease of 1