PURPOSE: To reduce the pressure loss when an intake air is passed through an air cooler by forming a flow down water film by flowing down water from an entrance to an inside and providing plural heat transfer pipes for cooling the air for gas turbine combustion by evaporating the flow down water and an absorber for absorbing generated vapour into lithium bromide water solution.

CONSTITUTION: A flow down water film is formed by flowing down water from an entrance into a pipe and a heat transfer pipe 5 for cooling the air for gas turbine combustion flowing in an intake air flow passage 4a by evaporating the flow down water on the flow down film is provided and vapour generated here is absorbed into a lithium bromide water solution in an absorber 10. Water flowing in from the heat transfer pipe 5 is stored in a water storing tank 8 and water in the water storing tank 8 is returned to the entrance side of the heat transfer pipe 5 by a pump 9. The lithium bromide water solution absorbed water is sent to a generator 16 by the pump 14 and here the water solution is heated and the vapour is extracted and condensed, while the condensed water solution after the vapour is extracted, is returned to the absorber 10.