Abstract: Combustion systems and associated methods are disclosed herein. In some embodiments, a combustion system comprises a first combustion zone, a second combustion zone downstream of the first combustion zone, and a heat module thermally coupled to the first combustion zone and/or second combustion zone. The first combustion zone is configured to (i) receive and combust preheated air and a first fuel and (ii) generate a first exhaust gas, and the second combustion zone is configured to (i) receive and combust the first exhaust gas and a second fuel and (ii) generate a second exhaust gas. The first exhaust gas can have a first excess air and the second exhaust gas can have a second excess air less than the first excess air. The heat module can comprise a thermionic converter or another heat-to-electricity converter able to generate a power output.

Abstract: Various disclosed embodiments include thermionic energy converters and electronic circuitry for generating pulses for igniting plasma in a hermetic package of a thermionic energy converter. In various embodiments, an illustrative thermionic energy converter includes a hermetic package charged with a non-cesium gas additive. The hermetic package is configured to route into the hermetic package pulses for igniting plasma in the hermetic package. A cesium reservoir is disposed in the hermetic package. A cathode is disposed in the hermetic package and an anode is disposed in the hermetic package.

Abstract: Systems for producing hydrogen gas for local distribution, consumption, and/or storage, and related devices and methods are disclosed herein. A representative system includes a pyrolysis reactor that can be coupled to a supply of reaction material that includes a hydrocarbon. The reactor includes one or more flow channels positioned to transfer heat to the reaction material to convert the hydrocarbon into an output that includes hydrogen gas and carbon particulates. The system also includes a carbon separation system operably coupled to the pyrolysis reactor to separate the hydrogen gas the carbon particulates in the output. In various embodiments, the system also includes components to locally consume the filtered hydrogen gas.