Dispenser nozzle freezing during hydrogen refuelling

This entry refer to a series of events occurred before the date given, which corresponds to the publication of the evidences at the Int. Conference on Hydrogen Safety 2015.
The nozzle/receptacle connection froze when refuelling the on-board hydrogen storage system at the lowest precooling temperature of -40 C.
However, freezing did not cause apparatus damage nor hydrogen leakage. The nozzle/receptacle is thus able to fuel safely even if the nozzle/receptacle is stuck due to ice.

The low temperature of the hydrogen caused the water vapour in the atmosphere to freeze around the nozzle-receptacle connection. Under specific environmental conditions creating high humidity, the quantity of ice forming does not allow for decoupling of the connection after the refuelling.

nozzle - receptacle connection

Despite the impossibility to decouple the connection, no damage is caused to the components. It is enough to wait for de-icing.

Under certain environmental conditions, air humidity can precipitate as ice around the nozzles/receptacle connection.
The results of the research presented at the ICHS2015 confirmed that the possibility of hydrogen leakage or damage to the apparatus during nozzles/receptacle connection freezing is low and that it is safe. Freezing at the hydrogen station will only prolong fuelling time.

The standards prescribing nozzle - receptacle designs were adapted.