A system includes a housing for a gas turbine engine, and a fan disposed in the housing to rotate coaxially with a gas turbine included in the housing. The system also includes an inlet guide vane disposed in the housing in axial alignment with the fan and configured to have an open position where a first flow of air is received by the fan through the inlet guide vane, and a closed position where airflow through the inlet guide vane is obstructed. The system further includes a heat exchanger disposed in a supply passage in fluid communication with a second flow of air received by the fan. The second flow of air is received by the fan via the supply passage with the inlet guide vane in the open position or in the closed position.