A method and system for thermal management includes an engine heat exchanger configured to transfer waste heat from an engine to a heat transfer fluid and an engine exhaust heat exchanger coupled in flow communication with the engine heat exchanger wherein the engine exhaust heat exchanger is configured to transfer heat from an exhaust of the propulsive engine to the pumped heat transfer fluid. A bypass valve is coupled in parallel with the engine exhaust heat exchanger wherein the bypass valve is selectable to modulate a flow of the heat transfer fluid through the engine exhaust heat exchanger and a plurality of accessory heat exchangers that are coupled in flow communication with at least one of the engine heat exchanger and the engine exhaust heat exchanger and each of the plurality of accessory heat exchangers flow is controllable using a modulating valve.