[ aviation ]
Type 1 steel cylinder filled to 200 bar pressure being hydrogen and the remainder being steel . This equates to a gravimetric efficiency of 1 %.
When using innovative , high-pressure carbon fibre Type 4 gas cylinders with a pressure of 700 bar ( as are standard in hydrogen fuelled cars ) the gravimetric efficiency of storage is still only 5 %. This may be acceptable for a very light drones , but this is not adequate for commercial aviation .
Switching to liquid hydrogen means that under current technical limitations , a metal storage tank must be used . Even when using cryogenically compatible aluminium alloys in place of heavier steel , the gravimetric efficiency of liquid hydrogen storage is currently limited at around 30 %.
Moonshot
For vertical take-off in a helicopter or drone , the focus shifts to gravimetric energy density as the
key parameter . For space rockets , the weight issue is even more acute .
The first large-scale application of liquid hydrogen was as a rocket-fuel for NASA missions . The hydrogen storage sphere built in the 1960 ’ s by CB & I at Lauch Complex 39B of Cape Canaveral ’ s Kennedy Space Center remained the largest liquid hydrogen storage tank in the world for many years . It has a usable capacity of 2,800 m ³ of liquid hydrogen and was used for the Apollo and space shuttle launches .
In 2022 , the crown for the world ’ s largest liquid hydrogen storage tank was passed to a larger tank at Kennedy Space Center . Again , CB & I was awarded the contract to build a new tank of 4,700 m ³ capacity at the same launch complex . The larger volume can support longer missions , and a more modern design with improved insulation will reduce liquid hydrogen boil-off losses . GenH2 sLH 2 tank filling . Image © Daimler Truck
36 Hydrogen Tech World | Issue 17 | August 2024