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Lightweight Radiators Being Developed or Advanced Stirling Radioisotope Power SystemsThe thermodynamic heat-to-electric power conversion efficiency of Stirling systems is 3 to 5 times higher than that of thermoelectric converters. Hence for unmanned deep space probes, Stirling advanced radioisotope power systems (ARPS) could deliver up to 5 times as much power as radioisotope thermoelectric generators for the same amount of radioisotope, or they could require one-third to one-fifth as much isotope inventory for the same power output. However, Stirling power systems reject unconverted heat at much lower temperatures than radioisotope thermoelectric generators. Normally, this requires larger and heavier heat-rejection subsystems because of the greater radiator areas, which are proportional to the first power of the heat rejected and the fourth power of the absolute heat-rejection temperature, as specified by the Stefan-Boltzmann radiation heat transfer law. The development of directly coupled disk radiators using very high conductivity encapsulated thermopyrolitic graphite materials represents a significant advance in Stirling ARPS space heat-rejection subsystem technology. A conceptual Stirling ARPS with two engines coupled to a radioisotope general-purpose heat source (GPHS) is shown in the illustration.
Document ID
20050195879
Acquisition Source
Glenn Research Center
Document Type
Other
Authors
Juhasz, Albert J.
(NASA Glenn Research Center Cleveland, OH, United States)
Tew, Roy C.
(NASA Glenn Research Center Cleveland, OH, United States)
Thieme, Lanny G.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
September 7, 2013
Publication Date
March 1, 2001
Publication Information
Publication: Research and Technology 2000
Subject Category
Energy Production And Conversion
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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