US Patent 9982629 Engine driven by SC0

A gas turbine engine includes a first shaft coupled to a first turbine and a first compressor, a second shaft coupled to a second turbine and a second compressor, and a third shaft coupled to a third turbine and a fan assembly. The turbine engine includes a heat rejection heat exchanger configured to reject heat from a closed loop system with air passed from the fan assembly, and a combustor positioned to receive compressed air from the second compressor as a core stream. The closed-loop system includes the first, second, and third turbines and the first compressor and receives energy input from the combustor.