Construction of a Thermionic Energy Converter

Some of the general design considerations for a cesium vapor-type thermionic energy converter are discussed. These include the questions of geometry and materials as well as cathode support and cathode lead design. The effect of the internal magnetic fields has been analyzed; it was found that there exists an upper optimum limit for the power handling capability per unit cell. The actual construction of a high power thermionic energy converter is described. This unit is of coaxial geometry having the anode surrounding the cathode and heat source. Laboratory testing of this cell is described and includes cold vacuum testing as well as high power operation using an electrical heat source external to the cell. For a device having a molybdenum cathode at 2525°K, a power output of 270 watts was obtained. The efficiency was about 3 per cent, which is in fair agreement with design predictions.