A mobile certification system to ensure gaseous hydrogen refueling equipment is in compliance with international standards has been introduced by ZSW, the Centre for Solar Energy and Hydrogen Research in Baden-Württemberg. This device measures pressure and temperature during refueling, checks the infrared communication between the vehicle and the filling station, and detects the amount of delivered hydrogen.
Hydrogen refueling stations for fuel cell-powered cars have one thing in common with conventional gas pumps — they must be inspected and approved before they are put in operation, and regular checked for quality afterwards. with this new system, samples are taken at the same time, and then the hydrogen is analysed for impurities. All this is aimed to drive the roll out of hydrogen infrastructure and promote adoption of climate-friendly, alternative mobility solutions.
Hydrogen (H2) is easily produced from regenerative sources in large quantities. And due to its high energy content it is an ideal fuel for fuel-cell vehicles. Filling a tank with compressed gas stored at 700 bar takes just three minutes or so, providing enough fuel for the vehicle to travel 400 to 700km. And with manufacturers now rolling out fuel-cell vehicles, hydrogen refueling stations are going up around the world.
Certifying authorities inspect conventional filling stations for liquid fuels to confirm that they deliver the indicated amounts — they have been doing this for some time, so standards for assessing the quality of these fuels are well established. However, the specifications for hydrogen are fairly new. An emerging fuel that is soon to be readily available, H2 gas is pumped into the tanks of fuel-cell vehicles at high pressure. This is why the regulations in place for the safe handling of gases also apply to H2 stations.
'Refueling protocols' based on industry standards determine hydrogen-related specifications such as the temperature range during gas delivery and compression, quantity measurement, leak detection during the dispensing process, and the like. All this has to be verified during the initial certification and periodically inspected afterwards. The tests for this inspection are documented in SAE J2601 — published in 2014, this technical industry standard sets out to harmonise worldwide the regulations governing the use of hydrogen.
With the ZSW's new mobile inspection system for H2 stations, researchers can check for compliance with pressure and temperature limits — the infrared communication between the vehicle and the refueling station in accordance with the SAE J2601 — and the dispensed amount of hydrogen using an integrated scale and a precision flow sensor.
ZSW is also working on online monitoring solutions to speed up hydrogen quality assessments. Pivotal electrochemical experiments recently demonstrated the viability of a new hydrogen quality sensor that is highly sensitive to contaminants in hydrogen. The centre's scientists aim to make hydrogen quality monitoring at filling stations easier and more cost-effective.
Further information on this new mobile measurement system for hydrogen fuel-cell technology will be presented at the ZSW booth H71 at the Hannover Messe on April 24-28.