Radioisotope Power Systems with Skutterudite‐Based Thermoelectric Converters

The performance and specific electrical powers of Radioisotope Power Systems (RPSs) with Skutterudite‐based Thermoelectric Arrays (SKTAs) of 2×7 and 4×7 unicouples connected electrically in series are calculated as functions of load voltage from 24 to 38 VDC. The p‐legs of the unicouples are made of CeFe3.5Co0.5Sb12 and the n‐legs are made of CoSb3, and the optimized cross‐section areas of these legs for maximum efficiency operation are calculated as functions of the RPS terminal voltage. The RPS employs five General Purpose Heat Source (GPHS) bricks, generating 1250 Wth at BOM, and 40 SKTAs, which are connected in series in two or four parallel strings. The peak electrical power and peak conversion efficiency of the SKTAs (20 mm long) occurs at the same electrical current because the unicouples operate at constant hot junction temperature (973 K) and constant input thermal power. The cold junction temperature of the unicouples and the radiator base temperature are determined from coupling the unicouples ...