Evaluation of the CBC-ORC energy system in lunar base: Working fluid combination selection, day and night operation performance

The lunar energy system must be able to provide continuous power supply on the day and night. However, the moon night is as long as 14 days, and the solar power generation system can't work without solar radiation. The solution is that part of the heat in the daytime is used for storage, the other part is used for daytime power generation, and the heat stored in the daytime is used for power generation at night. Based on this, this paper proposes a closed Brayton cycle and organic Rankine cycle combined power generation system, and explores the operation performance of the composite power generation system in the whole lunar day process. The results show that the combination of He-Xe and toluene has the best performance among many working medium combinations. The thermal efficiency of the system can reach 33.82 %, and the heat exchange area of the radiator is 970.99 m(2). Combined with supercritical CO2, the thermal efficiency is increased by 5.2 % and the heat exchange area is reduced by 8.5 %. In addition, in the case of night, the Brayton cycle system stops working at 7.75 earth days, which can maximize the power generation capacity of the coupling system, with a power generation capacity of 94.8 MJ.