Decentralized I/O System for Hazardous Areas at H2 Refueling Stations

In Resato Hydrogen Technology’s modular hydrogen refueling stations, Turck's IP67 ATEX I/O modules scalability and fast commissioning.

Companies investing in hydrogen infrastructure today place a lot of importance on the scalability of a system in order to be able to respond flexibly to future market requirements. This is precisely why the Dutch hydrogen filling station manufacturer Resato Hydrogen Technology B.V. relies on Turck's decentralized IP67 I/O module concept. It is the only one on the market that offers a comprehensive solution for modular systems, even in hazardous areas - and for all signal types including safety.

''Turck even recommended the exact cable types with the right lengths for us.'' Niels de Jong
The buffer storage tanks hold the hydrogen ready for refueling at 350 bar (truck) or 700 bar (car)
With TB-SG stainless steel protective housings, most TBEN I/O modules are approved for use in ATEX zone 2
IMC interface devices in IP67 allow safe connection of Ex sensors to the I/O modules in zone 2
''Turck was able to offer us different solutions for IP67 in ATEX zones.'' Remco Lagendijk
''Turck even recommended the exact cable types with the right lengths for us.'' Niels de Jong

Hydrogen will play an important role as an energy carrier in the future. Buses and trucks in particular will increasingly run on hydrogen. One of the companies profiting from this trend with its hydrogen filling stations is Resato Hydrogen Technology B.V. from Assen in the Netherlands. The core of the company's innovation lies in high-pressure technology.

Two pressure levels for trucks and cars

The hydrogen from the tube trailer is compressed to 350 bar in three stages and cooled down. It is then stored in buffer tanks for refueling trucks or, in a fourth compression stage, compressed to 700 bar and stored in a separate buffer. Due to the precooling of hydrogen cars can be refueled much more quickly via 700-bar pumps.

A hydrogen filling station is therefore much more complex than a filling station for carbon-based fuels. The system must bring the hydrogen to the necessary pressure in a series of cooling and compression steps.

Hydrogen requires explosion protection concept

Resato developed a patented algorithm that realizes the fastest possible refueling depending on temperature and pressure. At the I/O level, explosive hydrogen poses a challenge to the automation concept. It requires an explosion protection concept and products with the appropriate approvals. The signals to be processed are mainly temperature and pressure signals as well as switching signals from control valves. In addition, there are safety-related signals from valves, emergency stop buttons and other safety sensors.

Modularization for more flexibility

To make it easier to add aggregates, all signals on each aggregate must converge in one data line. The buffer storage units therefore require an I/O solution with Industrial Ethernet, or more precisely Profinet. Since Resato wanted to save on protective housings and the mechanical effort involved, the experts looked for I/O modules with IP67 protection, which are temperature-resistant and suitable for outdoor use. However, the modules should also have approval for ATEX zone 2 and also be suitable for connecting intrinsically safe signals from zones 1 and 0.

Intensive consulting during concept development

As a result, Resato worked with Turck experts to develop a decentralized I/O concept for its buffer storage units. "The support was really good. We weren't handed a few products and told 'Good luck with that,' but we had an intensive exchange about the products and thought through different possibilities. Turck even recommended the exact cable types with the right lengths for us," explains Niels de Jong, research and development engineer. "Resato's ambition is to be the global technology leader in the field of hydrogen refueling stations. For this, we need partners like Turck.".

The I/O concept was implemented completely decentralized - including the intrinsically safe sensor signals from ATEX zones 0 and 1. With the devices of the IMC family, Turck offers special interface modules in IP67.

Consistently modular - optimally scalable

Resato has thought the modular concept through to the end. Remco Lagendijk and his colleagues from software development have also made the control software modular. Thanks to the consistently modular concept, Resato's hydrogen fueling stations are now conceivably easy to scale.

Next stop: series production

Demand for the hydrogen filling stations is rising continuously. The individual modules, such as compressors or buffer storage units, can be pre-produced in stock and then assembled to meet specific customer requirements. These economies of scale will also reduce the costs and time-to-market of hydrogen filling stations.

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