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 performance optimization model with a detailed radiation thermal analysis for sizing the aluminum fins for rejecting waste heat into space. The calculated peak specific powers and the corresponding electrical powers of the RPSs at Beginning‐Of Mission (BOM) are compared with those calculated at the peak electric power at different load voltages. Results indicated that the value of the load voltage strongly affects the performance of the RPS. Both the RPS peak specific powers and those corresponding to the peak conversion efficiency / peak electrical power increase with increasing the load voltage up to certain values then drop with further increasing that voltage. The highest BOM specific powers of the RPS is ∼ 6.859 –6.973 We/kg, ∼ 43.3% and 45.7% higher than that of the RTG (4.786 We/kg) with 7 GPHS brick and SiGe unicouples. Such specific electrical powers of the RPS with SKTAs are attainable with 28.6% less 238PuO2 fuel and 2.85% to 11.62% more BOM electrical power (122 We) than the RTG (105 We).


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    Title :

    Radioisotope Power Systems with Skutterudite‐Based Thermoelectric Converters


    Contributors:

    Conference:

    SPACE TECHNOLOGY AND APPLICATIONS INT.FORUM-STAIF 2005: Conf.Thermophys in Micrograv;Conf Comm/Civil Next Gen.Space Transp; 22nd Symp Space Nucl.Powr Propuls.;Conf.Human/Robotic Techn.Nat'l Vision Space Expl.; 3rd Symp Space Colon.; 2nd Symp.New Frontiers ; 2005 ; Albuquerque, New Mexico (USA)


    Published in:

    AIP Conference Proceedings ; 746 , 1 ; 485-494


    Publication date :

    2005-02-06


    Size :

    10 pages





    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English