Anticipated exhaustion of the fossil fuel and expanding global environmental problems call for the new energy resources, which are preferably clean in itself and obtainable over a long term. Among the candidates hydrogen is deemed to be one of the promising selections as the relief roles till the technological realization of the nuclear energy of next generation or the alternative one. The production site of hydrogen is required to be located at the regions of abundant natural energy e. g. solar or hydraulic energy available because of its characteristics as the artificial carriers of primary energy. Produced hydrogen gas may be liquefied or synthesized to the third materials for the convenience of the sea transportations. In this paper, exclusively liquefied hydrogen (LHG) is treated by reason of small amount of energy consumption and limited CO₂ emission during its production, focussing on the analysis of thermodynamics of very low temperature state. Tank system should be designed by the new concept due to the handling of cargo at the cryogenic temperature region as low as 20 K which is not situated on the linear extensions of LNG carrier's technology. In this paper the concept and configurations of the systems for tank and machinery including cargo tank and support, vacuum insulation, cargo transfer and cargo reliquefaction etc. of LHG carrier are proposed and related analytical solutions are described.