Thermal Analysis of a Hydrogen Bulk Gas Transport System

Hydrogen bulk gas transport (BGT) systems are needed to provide efficient movement of carbon-free energy.This study considers containerised or trailer-mounted BGT systems comprising an array of high-pressure hydrogen cylinders.Rapid filling of such cylinders leads to large changes in gas temperature which may exceed the maximum temperature limit of the cylinder materials.Therefore the filling rate is limited by the rate at which heat can be dissipated from the cylinder.This study develops, validates and applies lowdimensional models for the thermal response of hydrogen cylinder arrays, characterising how different design choices affect the minimum filling time for BGT systems subject only to natural convection.Validity of the low-dimensional modelling is supported by comparison with three-dimensional computational fluid dynamic simulations.This study considers BGT systems with vertically-oriented cylinders and analyses the effects of inline or staggered arrangements of cylinders, cylinder diameter, cylinder spacing, and fill rate.It is found that the BGT system filling rate is limited primarily by convective heat transfer from the outer cylinder walls.Heat transfer tends to improve for systems with smaller cylinder diameter and larger cylinder spacing.The heat transfer rate is greatest for widely-spaced staggered cylinder arrangements, however close-packed arrangements provide a better compromise between overall storage density and fill time.