[ gas cooling ]
Compressed hydrogen gas is stored in the static intermediate pressure storage tanks at a hydrogen refuelling station ( HRS ) for buses or trucks at around 500 bar . For cars , the highpressure storage at the HRS may be at around 900 bar . When the vehicle is connected to the HRS , hydrogen gas flows through the refuelling hose and nozzle from the high-pressure storage into the vehicle tank , which is at a lower pressure . Under these conditions , hydrogen gas has a Joule-Thomson coefficient less than zero and the temperature of the hydrogen gas increases .
The hydrogen storage tank on the vehicle is designed to operate at less than 85 ° C and has safety devices that release hydrogen when the storage tank becomes overheated . It is common to use a glass bulb thermal pressure relief device ( TPRD ), which bursts at 110 ° C . If the TPRD is activated and the glass bulb breaks , the contents of the hydrogen tank are rapidly vented .
In recognition of the growing demand for onboard hydrogen storage systems , the German high-pressure systems and equipment supplier , POPPE + POTTHOFF , has recently introduced a TPRD for hydrogen
° LAUDA HRS cooler . Image © Lauda Dr . R . Wobser GmbH & Co . KG
storage tanks into their range of gas control equipment .
To prevent the storage tank from becoming damaged or the relief devices being deployed , the hydrogen gas must be chilled between the high-pressure storage at the HRS and the vehicle . For this purpose , a hydrogen gas cooler must be included as an element of the HRS gas dispense equipment .
Cryogenic liquid hydrogen storage on a truck
Indirect coolers with thermal energy storage
Hydrogen leaving the compressor or storage tank can be as warm as 60 ° C . From this temperature , it must be cooled to -10, -20, -30, or -40 ° C , according to the relevant protocol in the SAE J2601 standard . Hydrogen gas cooling equipment manufactured by ° LAUDA is designed to cool hydrogen with a temperature delta of around 100 ° C , from 60 ° C to -40 ° C .
46 Hydrogen Tech World | Issue 16 | June 2024