Structural Design and Thermal Performance Analysis of Heat Source Used in Radioisotope Thermophotovoltaic

Radioisotope thermophotovoltaic (RTPV) is playing an increasingly important role in the energy supply for deep space exploration. The output performance of RTPV can be significantly improved by increasing the temperature of the heat source and reducing the thermal effect of the TPV cells. In this study, the gains of different coating emissivity, thermal power and structure on the temperature of heat source were compared based on the finite element method. Results showed that the surface temperature of the heat source could generally reach more than 1000 K by using the selective coating when the heat source thermal power was 500 W. The use of suitable selective coatings can also make the TPV cell closer to the heat source, and the volume of RTPV could be reduced from 1.23×10 −3 m 3 to 0.49×10 −3 m 3 , with a reduction of ~60%. Under the condition of W@SiO 2 selective coating and 500 W heat source, InGaAs cell could produce the maximum output power of 22 mW/cm 2 at 2 cm distance from the heat source. The results provided effective guidance for the design of the heat source and miniaturization of RTPV systems in space applications.