Numerical analysis on lunar heat storage system: Multi-objective optimization, heat storage capacity, and thermal insulation performance

Abstract

The long lunar night of 14 earth days without solar radiation has become the biggest obstacle to the continuous energy supply system day and night. The lunar base heat storage system is one of the best solutions because it is possible to transfer energy from day to night for power generation. However, due to the diversity of energy demands of the lunar base, it is inevitable to study the thermal storage performance of the heat storage system at different periods. In this paper, based on three objective parameters: effective time of heat storage (teff), heat storage capacity (Q), and system entropy increase (Sgen) of the heat storage process, a multi-objective optimization design of heat storage system is carried out. In addition, to solve the heat dissipation problem of the lunar night, the natural lunar regolith insulation layer was added to evaluate the heat storage and insulation of the lunar night. The results show that different types of the heat storage system can be obtained by changing the structure parameters. The heat storage efficiency of the heat storage system with a large radius is still 0.59 after a long period of heat storage. The minimum thickness of the varied-temperature layer can be reduced to 60 % of the height of the whole system. Additionally, the insulation layer can effectively reduce energy loss at night, but the effect of improving thermal insulation performance is limited when the insulation layer thickness is too thick.