Thermionic energy converters

Patent · Tue Feb 08 04:00:00 EST 1983

OSTI ID:6207242

Morris, J F

This invention is concerned with improving the efficiency of thermionic energy converters. The invention is particularly directed to the reduction of plasma losses in these converters. This beneficial technical effect is achieved by internal distribution of tiny shorted cesium diodes driven by the thermal gradient between the primary emitter and the collector. Specifically, the tiny, shorted diode distribution comprises protrusions of the emitter material from the main emitter face which contact the main collector face thermally but not electrically. The main collector ends of the protrusions are separated from the main collector by a thin layer of insulation, such as aluminum oxide. The diode effect will increase with the use of metals that adsorb cesium less readily for the main emitter ends of the tiny protrusions and metals that adsorb cesium more readily for the main collector ends of the protrusions. By way of example, the main emitter can be made of rhenium or irridium; the main emitter ends of the protrusions can be made of tantalum or niobium; and the main collector ends of the protrusions can be made of platinum or irridium. The shorted tiny diode distribution augments cesium ionization through internal thermal effects only within the main diode. No electrical inputs are required. This ionization enhancement by the distribution of the tiny shorted diodes not only reduces the plasma voltage drop but also increases the power output and efficiency of the overall thermionic energy converter.

• Assignee: Administrator of NASA
• Patent Number(s): US 4373142
• OSTI ID: 6207242
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300401* -- Thermionic Converters-- Design & Development
300402 -- Thermionic Converters-- Performance & Testing
ALKALI METALS
CESIUM
DESIGN
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELEMENTS
METALS
NESDPS Office of Nuclear Energy Space and Defense Power Systems
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
THERMAL INSULATION
THERMIONIC CONVERTERS