A comparison of projected thermoelectric and thermionic refrigerators

Expressions for the coefficient of performance and the cooling power of a thermionic refrigerator are derived taking into account the losses associated with thermal radiation and the need for a so-called passive conductor in the electrical circuit. Specific calculations are made for a thermionic device with a work function of 0.3 eV and it is shown that the performance is generally superior to that of a thermoelectric refrigerator made from materials with a dimensionless figure of merit ZT equal to 4. (C) 1999 American Institute of Physics. [S0021-8979(99)02308-7].