An airflow control system for a gas turbine system according to an embodiment includes: a compressor component of a gas turbine system; a mixing area for receiving an exhaust gas stream produced by the gas turbine system; an air extraction system for extracting a supply of bypass air from an excess flow of air generated by the compressor component of the gas turbine system; an enclosure surrounding the gas turbine system and forming an air passage, the bypass air flowing through the air passage and around the gas turbine system into the mixing area to reduce a temperature of the exhaust gas stream; and an exhaust processing system for processing the reduced temperature exhaust gas stream.