Two-dimensional thermal analysis of liquid hydrogen tank insulation

Liquid hydrogen (LH2) storage has the advantage of high volumetric energy density, while boil-off losses constitute a major disadvantage. To minimize the losses, complicated insulation techniques are necessary. In general, Multi Layer Insulation (MLI) and a Vapor-Cooled Shield (VCS) are used together in LH2 tanks. In the design of an LH2 tank with VCS, the main goal is to find the optimum location for the VCS in order to minimize heat leakage. In this study, a 2D thermal model is developed by considering the temperature dependencies of the thermal conductivity and heat capacity of hydrogen gas. The developed model is used to analyze the effects of model considerations on heat leakage predictions. Furthermore, heat leakage in insulation of LH2 tanks with single and double VCS is analyzed for an automobile application, and the optimum locations of the VCS for minimization of heat leakage are determined for both cases. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.