Abstract: A gas turbine driven power system includes a shell having an air inlet and an exhaust outlet. Mufflers are provided at the air inlet and the exhaust outlet, respectively. A gas turbine as a power source is provided in the shell and includes an inlet port and an outlet port. A heat exchanger is further provided in the shell in an air-passing space free of barrier formed between the muffler at the air inlet and the inlet port of the gas turbine. It is so arranged that all the air introduced into the shell through the air inlet passes through the heat exchanger for heat exchange with heat generated inside the shell.