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Vapor Power Cycles and Alternative Power Systems
Published in Irving Granet, Jorge Luis Alvarado, Maurice Bluestein, Thermodynamics and Heat Power, 2020
Irving Granet, Jorge Luis Alvarado, Maurice Bluestein
The thermionic converter is basically a high-temperature device that converts thermal energy into electricity by literally boiling off electrons from the hot cathode, which then travel to the cold anode. Figure 8.21 shows a schematic of this device in which the electrical circuit is completed by the external load, RL. In principle, this device is a heat engine that uses electrons as the working fluid. Therefore, the upper limit of its efficiency is that of a Carnot engine operating between the temperature limits of the cathode and anode. Efficiencies of 10% have been achieved with cathode temperatures of 3200°F when the Carnot efficiency was 50%. Because electron emission is an exponential function of temperature, high cathode temperatures yield high power densities. Efficiencies of the order of 18% have been achieved in a thermionic converter with a cathode temperature of 4500°F.
Direct Energy Conversion
Published in D. Yogi Goswami, Frank Kreith, Energy Conversion, 2017
Mysore L. Ramalingam, Jean-Pierre Fleurial, George Nolas
In thermodynamic terms a thermionic converter is a heat engine that receives heat at high temperature, rejects heat at a lower temperature, and produces useful electrical work while operating in a cycle analogous to a simple vapor cycle engine. Based on the application of the first law of thermodynamics to the control volumes around the emitter (Houston 1959; Angrist 1976),
A Critical Review of Heat Pipe Experiments in Nuclear Energy Applications
Published in Nuclear Science and Engineering, 2023
Scott Wahlquist, Joshua Hansel, Piyush Sabharwall, Amir Ali
There are essentially two categories of space radiators: rejection at temperatures below 350 K and nuclear or high-power systems at temperatures around 500 K and beyond.163 Most direct space reactor cooling using HPs is accomplished by coupling HPs directly to thermionic converters. Each thermionic converter produces an electrical power output by emitting electrons over a potential energy barrier from a hot electrode to a colder electrode. The evaporator section of each HP is inserted into the reactor core while the condenser section is coupled to the hot electrode of each thermionic converter.