A novel cryogenic insulation system of hollow glass microspheres and self-evaporation vapor-cooled shield for liquid hydrogen storage

Abstract

Liquid hydrogen (LH2) attracts widespread attention because of its highest energy storage density. However, evaporation loss is a serious problem in LH2 storage due to the low boiling point (20 K). Efficient insulation technology is an important issue in the study of LH2 storage. Hollow glass microspheres (HGMs) is a potential promising thermal insulation material because of its low apparent thermal conductivity, fast installation (Compared with multi-layer insulation, it can be injected in a short time.), and easy maintenance. A novel cryogenic insulation system consisting of HGMs and a self-evaporating vapor-cooled shield (VCS) is proposed for storage of LH2. A thermodynamic model has been established to analyze the coupled heat transfer characteristics of HGMs and VCS in the composite insulation system. The results show that the combination of HGMs and VCS can effectively reduce heat flux into the LH2 tank. With the increase of VCS number from 1 to 3, the minimum heat flux through HGMs decreases by 57.36%, 65.29%, and 68.21%, respectively. Another significant advantage of HGMs is that their thermal insulation properties are not sensitive to ambient vacuum change. When ambient vacuum rises from 10−3 Pa to 1 Pa, the heat flux into the LH2 tank increases by approximately 20%. When the vacuum rises from 10−3 Pa to 100 Pa, the combination of VCS and HGMs reduces the heat flux into the tank by 58.08%–69.84% compared with pure HGMs.