A system for energy conversion is provided including a propulsion system, a fuel circuit, a combustion device and turbine separate from the propulsion system, and a load device. A fuel flow control device separates a flow of fuel from the fuel tank into a first portion of fuel and a second portion of fuel. A fuel circuit is configured to provide the first portion of fuel to a heat addition system at the propulsion system. A combustion device receives a flow of oxidizer from a compressor section of the propulsion system via a fluid circuit. The fuel circuit provides the second portion of fuel to the combustion device. The fluid circuit flows combustion gases to the turbine and the propulsion system. The load device is operably coupled to the turbine to receive an output torque via expansion of the combustion gases through the turbine.