PURPOSE: To prevent the output fluctuation of a gas turbin caused by atmospheric temperature while keeping air to be supplied to a compressor in desired low temperature by cooling the combustion air of the gas turbin through liquid fuel and a heat pipe.

CONSTITUTION: Branch lines 20 and 30 are provided on the seawater line 2A of an evaporator 2 to make it possible to supply pure water from a raw water tank 9, and a heat exchanger 8 for cooling air to be supplied to a compressor 5 is provided, allowing water after heat exchanging in the evaporator 2 to be circulated into said heat exchanger 8. The fuel of a gas turbin 4 is fed from a LNG tank 1, and is changed to normal temperature gas by an LNG evaporator 2 and sent to a combustor 3. On the other hand, combustion air required for the combustor 3 is sucked by an air compressor 5, and heat exchanged with water by the heat exchanger 8 provided at the inlet of the air compressor 5 to be adjusted to prescribed temperature.