Performance analysis of a particle-based lunar solar thermal power system

Energy systems constitute one of the most critical components in the construction of a lunar research station. As the exploration of lunar surface progresses, the demand for electricity and thermal energy will increase to 1∼10 kW in the future. Solar thermal power systems represent an effective solution for kilowatt lunar energy systems. Current designs mostly employ fluid as heat transfer media, which may suffer from limitations including low heat transfer rate, system instability, and transportation costs. Focusing on these issues, this study proposes a particle-based solar thermal power system for lunar applications, applying in-situ solid particles for collection and storage of thermal energy. The designed system achieves steady-state operation within approximately 4 lunar days. The average electric power output of the system can reach 4.57 kW, and the Stirling efficiency ranges from 20.4 to 27.0%. Furthermore, simulations are conducted on moving bed heat exchanger for particle heat transfer. Results indicate that improving the heat transfer performance of moving bed heat exchanger is an effective solution to enhance system efficiency, which can increase the average power output by up to 10%. Through exergy analysis, the radiator, Stirling generator, and MBHE are identified as the main exergy destruction components, with exergy destruction rates of 4.04, 2.96, and 1.90 kW, which can be regarded as the focus of system optimization.