Combined thermionic-thermoelectric refrigerator

Abstract

A combined thermionic-thermoelectric refrigerator is proposed. The passive metal conductor in a vacuum thermionic refrigerator is replaced by an active p-type thermoelectric element, so that the Peltier cooling power can be exploited. Complete analytic formulas of performances are derived for the two types of thermionic refrigerators at both maximum cooling power density and optimum coefficient of performance. In employing the ideal material properties as Nolas and Goldsmid have done [J. Appl. Phys. 85, 4066 (1999)], we have proved quantitatively the combined thermionic-thermoelectric refrigerator to be more effective and efficient than a thermionic or thermoelectric device. © 2002 American Institute of Physics.