Research on a lunar base combined thermodynamic cycle system integrating stirling engines: Cold energy migration, day-night thermodynamic performance, and power to weight ratio

To address the critical challenges of long-duration energy storage during the lunar nighttime and efficient heat dissipation under high-temperature daytime heat sinks, this paper proposes a coupled Closed Brayton Cycle (CBC)-Stirling Engine (SE) coupled power generation system for lunar bases. A steady-state thermodynamic model is established to evaluate the combined cycle performance across a complete lunar day-night cycle, wherein the Particle Swarm Optimization algorithm is employed to solve the SE model. During the lunar daytime, the CBC converts concentrated solar thermal energy into electricity, while the SE recovers waste heat from the CBC for secondary power generation. This configuration boosts the total power output by up to 48.6 kW compared to a standalone CBC system. At lunar noon, the system achieves a peak net output of 200.65 kW. During the lunar nighttime, stored high-temperature heat from the hot tank (HT) sustains CBC operation, the SE operates reversely as a refrigerator. A cooling capacity replenishment ratio of up to 103.36% is attainable. By the end of the lunar nighttime, the HT temperature drops to only 760.74 K significantly higher than the 615 K typically observed in conventional CBC-only systems, indicating superior thermal storage stability. Ultimately, this dynamically reversible CBC-SE architecture provides a highly efficient and self-sustaining thermal management solution, offering a robust thermodynamic pathway for the continuous operation of future deep-space habitats.