A system for energy conversion that includes a propulsion system, a fuel circuit, a combustion device, a turbine, and a load device. The fuel circuit is in fluid communication with a fuel tank and a fuel flow control device that separates a flow of fuel into a first portion and a second portion. The combustion device receives a flow of oxidizer and the second portion of fuel to generate combustion gases. The turbine receives the combustion gases from the combustion device via a fluid circuit. The load device is operably coupled to the turbine via a driveshaft and is configured to receive torque from the driveshaft.