Liquid hydrogen storage tank

The density of pure hydrogen is increased via its liquefaction to 70 kg/m3 at 1 bar. Due to the low boiling point of hydrogen (-253 °C) compared to natural gas (-162 °C), the design of cryogenic storage tanks seeks to minimise boil-off gas, preventing heat inleak. If hydrogen is evaporated, it must be vented to avoid an increase in the pressure in the storage tank. Small tanks are usually cylindrical but for larger volumes spherical tanks are used to minimise the surface-to-volume ratio, decreasing heat transfer. Liquid hydrogen storage tanks often feature a double-shell vacuum insulation, which minimises heat transfer via conduction and convection, and the space between the tank walls contains additional insulation materials. Cryogenic tanks are lighter than pressure vessels; however, liquefaction is an energy-intensive process compared to compression. Today, large-scale liquid hydrogen storage technology is relatively similar to that of the 1960s; however, design innovation is still needed to further scale up the tank size.