A general-purpose heat source (GPHS) is the most established heat source module for radioisotope thermoelectric generators (RTGs) and a key reference for the equivalence of electrically heated analog heat sources during the development and testing of radioisotope power supplies.

The study aims to develop a highly efficient electric heating simulation heat source to meet the requirements for equivalent testing and verification of non-nuclear units of radioisotope power systems.

Firstly, an electrically heated analog heat source was designed and imitated based on various actual GPHS performance parameters. Based on the simulation calculations, the thermodynamic equivalent substitutability between the simulated heat source and real GPHS in terms of material and dimensional differences was evaluated. Then, the performance of its operation in different application scenarios was analyzed, and an optimized application environment was proposed. Finally, based on the experimental test results, the uniformity of the thermal output characteristics of the imitation GPHS-simulated heat source was compared with that of a real GPHS, and the practical application characteristics of the imitation GPHS in RTGs were also evaluated.

At an input power of 250 W, the average surface temperature of the GPHS-simulated heat source reaches 515 K. The temperature variation trend with power is consistent with that of the simulation results. Experimental test results show that the energy conversion efficiency of the RTG module is increased to ~6% with a 250-W heat source power supply.

The proposed and constructed good equivalent simulated GPHS heat source with reference to the thermal properties of a real GPHS can be applied to RTGs and provides an effective and unified reference standard for the performance evaluation of radioisotope power sources.