Abstract: An indirect-fired gas turbine power plant comprises a compressor; a turbine mechanically coupled to the compressor; a furnace; a heat exchanger inside the furnace and fluidly coupled at an inlet end to the compressor and at an outlet end to the turbine; and means for forming a gas barrier around a portion of the heat exchanger to impede combustion products from contacting the heat exchanger. Such means can be a plurality of gas discharge manifolds located around a portion of the heat exchanger. The manifolds can be coupled to heated working gas exhausted by the turbine.