Increasing the Efficiency of a Thermionic Engine Using a Negative Electron Affinity Collector

Abstract

Most attention to improving vacuum thermionic energy conversion device (TEC) technology has been on improving electron emission with little attention to collector optimization. A model was developed to characterize the output characteristics of a TEC where the collector features negative electron affinity. According to the model, there are certain conditions for which the space charge limitation can be reduced or eliminated. The model is applied to devices comprised materials reported in the literature, and predictions of output power and efficiency are made, targeting the sub-1000K hot-side regime. By slightly lowering the collector barrier height, an output power of around 1 kW, at > or = 20% efficiency for a reasonably sized device (~0.1 sq m emission area) can be achieved.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2014
Accession Number
ADA595915

Entities

People

  • Joshua R. Smith

Organizations

  • United States Army Research Laboratory

Tags

DTIC Thesaurus Topics

  • Accumulators
  • Algorithms
  • Conduction Bands
  • Conversion
  • Current Density
  • Efficiency
  • Electron Emission
  • Electrons
  • Emission
  • Energy
  • Energy Conversion
  • Fermi Levels
  • Literature
  • Materials
  • Military Research
  • Photoexcitation
  • Space Charge

Fields of Study

  • Physics

Readers

  • Combustion and Flow Dynamics.
  • Electronics Engineering
  • Molecular Photonics/Laser Physics

Technology Areas

  • Microelectronics
  • Space
  • Space - Hall-Effect Thruster