Safe hydrogen applications testing

Interview with specialist Jörg Ruppert.

Hydrogen is back on the agenda for the automotive industry, especially when it comes to commercial vehicles. But the very thing that makes this substance a power source also makes it so sensitive. Keyword: safety. In the interview, Jörg Ruppert, engineer at Weiss Technik, explains which tests must be carried out to use this explosive element.

Some automakers are reporting that they are working on hydrogen-powered powertrains as an alternative to batteries. What are your thoughts on hydrogen applications in mobility?

With the shift away from fossil fuels and federal and state funding for hydrogen applications, there are research and development projects that we will see on the roads later. Hydrogen-powered vehicles and their components must pass the same environmental simulation tests as conventional vehicles with combustion or electric motors. Corresponding test systems are needed for this.

Are there already signs of increasing demand?

Definitely. Many car manufacturers are looking at hydrogen, as are their associated suppliers, i.e. companies that build components such as piping systems, valves, tanks or safety equipment. We are also seeing a strong increase in requests to convert existing test systems for hydrogen applications.

What environmental influences must be taken into account when using hydrogen vehicles?

In environmental simulations, the classic parameters are tested: high and low temperatures, for example, and rapid fluctuations, but also humidity and corrosion, which can build up as a result of salt fog in offshore applications, for example. Different weather conditions, radiation exposure to IR and UV light (heat build-up and aging) are also tested. All within a few days – in a rush, you could say.

What else is tested besides environmental influences?

It is important to investigate the impact of vibrations, as these can cause leakage. We also test the effects of under- and overpressure, which is particularly relevant for mobility at high altitudes or in aircraft.

Let’s return to the topic of “retrofitting”. Can a simulation system that has been used to test combustion or electric engines up until now be easily retrofitted to test hydrogen vehicles?

Yes, it is possible. At the start of a conversion, an extensive risk analysis is carried out. It is necessary to properly assess the dangers associated with the use of hydrogen, how incidents can be prevented and what countermeasures must be taken in critical situations. In other words: a thorough inspection of the system on site with inspection, advice and individual concept development.

Hydrogen is really quite aggressive. What does this mean for vehicle technology? And for testing?

That is correct. Hydrogen reacts easily with oxygen and is therefore flammable and highly explosive. These are properties that you have to take into account. It is important not to have any leaking areas, i.e. prevent the hydrogen from leaking. For example with small parts. Or double-strength tubes – a tube within a tube – with extra coating to exclude corrosion. These are the type of supply lines that are used in systems where, for example, fuel cells are tested. They also have quick-closing valves that close immediately if hydrogen is released.

If, despite all safety measures, hydrogen leaks, what should you take into account?

If that happens, we must prevent an explosive mixture from forming. The amount of hydrogen released, in relation to the volume of the space and the duration of the leak, determines the risk. As a rule of thumb, if the amount is minimal and the time unit is long, it is manageable. If the released amount is large and the time unit is short, it becomes dangerous.

What measures are necessary in a critical situation?

The danger must be detected and signaled quickly. Another emergency measure is to dilute the hydrogen by flushing. Here too, it is important where the leak originated – the size of the room, for example, determines to what extent the hydrogen must be diluted. In the event of a concrete explosion hazard, switching off the system is the only option.

What does that mean for production in terms of processing and cleanliness?

Hydrogen pipes and tank systems are of course a tricky point. Impurities are mainly caused by the operating conditions, such as extreme temperatures or high pressure. The hydrogen must also have the right purity, otherwise corrosion can quickly occur. Care is required, both during implementation in the system and during processing, to prevent leaks and damage to the surfaces.

With hydrogen, it is all about safety, or the quality of all the components. What else is being tested?

Performance is part of quality assurance. Component performance is just as important to testing as safety. Users want to know how their components perform under what conditions. When does performance decrease, when does it increase?

From which industries could automakers pick up successful approaches to dealing with hydrogen technology?

The chemical and energy industries. And also the maritime, aviation and space sectors, with all the suppliers of systems and components. Maybe we will soon see small aircraft flying on hydrogen. There have already been hydrogen aircraft, or hydrogen combustion engines. Hydrogen is already used in the commercial vehicle industry.

Since developing and testing hydrogen technology requires a major investment in safety, the question is: could we not work with less dangerous substitutes?

The specific properties of hydrogen, and therefore also the risks, cannot be replaced by other elements in the test. Therefore, a targeted risk assessment and hazard analysis with the associated safety measures is essential. Furthermore, a substitute material would make little sense, since the products that are to be powered by hydrogen later require the corresponding approvals.

Finally, let us briefly consider the possible alternative materials in the field of mobility. Synthetic fuels, also known as e-fuels, could be an alternative to hydrogen. Do you take this into account when developing your simulation systems?

We plan our test facilities in close consultation with our customers. In doing so, we take into account special requirements, including those concerning fuels. The basis for this is knowing the properties of the materials, adjusting the sensors accordingly and ensuring fire prevention. Weiss Technik adapts the systems to the respective risk analysis and we advise and sensitize our customers accordingly.

Original article: https://www.weiss-technik.com/environmental-simulation/en/news/detail/test-hydrogen-applications-safely~n28959