PURPOSE: To prevent a drop in generating capability especially in the summer season by providing a water cooler of steam heating absorption type and using the air cooled down therein for cooling intake air for an air compressor via an air cooler, in a system combined with an exhaust heat recovery boiler.

CONSTITUTION: Air from an intake passage 5 is compressed with an air compressor 6 and the compressed air of high pressure is supplied to a combustor 7, thereby contributing to fuel combustion. A high pressure gas generated therein is used to turn a gas turbine 8, thereby driving a generator 10. A combustion gas coming out of the gas turbine 8 is introduced to an exhaust heat recovery boiler 2 for generating and supplying steam from a steam feed pipe 13 to a load system. In the aforesaid generating system, a water cooler 3 of steam heating absorption type using steam as a heating source necessary for recovering an absorbed liquid is connected to the steam feed pipe 13 via a steam introduction pipe 14. Also, an air cooler 14 is provided in an intake passage 5, thereby making the constitution wherein the air in the intake passage 5 is cooled down via heat exchanged with cold water from the water cooler 3.