Pioneer's innovative Cascade Technology

Offering more hydrogen refills and greater utilisation


Pioneer Cascade Technology

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There are typically two ways to transfer hydrogen gas from one receptacle to another without using a compressor: This is decant or cascade technology.

Both methods utilise the pressure gradient between a higher-pressure source and the low-pressure target tank to move hydrogen fuel without any external energy requirements.

Decant Technology

A decant system takes a high-pressure system of a certain volume and is connected to the target system also at a certain volume and at a lower pressure.

The systems are opened to one another and the hydrogen flows from high pressure to low pressure. This movement of gas stops when both systems have reached the same pressure. This is known as equalisation.

Pioneer Cascade Technology

The Pioneer Hydrogen Refuelling Station utilises cascading refuelling, which is essentially an automated sequence of individual decants. This technique enables the filling of significantly more vehicle tanks to higher fill pressures & greater hydrogen utilisation from the refueller than through simple decant filling.

A cascade filling system is a multi-bank high-pressure gas cylinder storage system which is used for the refilling of smaller compressed gas cylinders.

Read more on the Pioneer and its innovative, low-cost solution!

Principle of Operation

Decant fill

When hydrogen gas, contained in a source cylinder at high pressure, is allowed to flow to the receiving cylinder containing gas at a lower pressure, the pressures will equalise to a value somewhere between the two initial pressures. 

This result is that the receiving cylinder is partially filled.

Cascade Fill

Multiple source cylinders are used. The receiving cylinder will first be fuelled from one of the source cylinders, which like the simple decant fill will result an incomplete fill.

The second and third source cylinders will then be connected, in turn bringing the receiving cylinder to a higher pressure at every step. 

This approach optimises utilisation of hydrogen from a standard source cylinder and results in the receiving cylinder being completely filled.

Filling protocols and safety checks on a cascade refueller are controlled by the onboard PLC and operation is via a simple push button interface.

Decant Vs Cascade Comparison

This graph indicates the relative performance of the two solutions when filling a bus tank.

A full fill = 20kg for a typical large hydrogen bus application.

The 4 bank cascade method vs 9 bank cascade method demonstrates that a 4 bank system provides faster refuels. A 9 bank system offers better gas utilisation, to which a Pioneer Hydrogen Refuelling Station can be configured.

NanoSUN's Pioneer Hydrogen Refuelling Station's incorporation of innovative cascade technology offers faster refuel times and better hydrogen gas utilisation.

Unlike traditional fixed refuelling stations, cascade refuellers require no external power source or moving parts hence they work well for reliable field and mobile hydrogen refuelling. An additional benefit of the cascade system is the ability to meet the demand of filling several small cylinders in close succession, whereas filling from a traditional compressor with buffer cylinder often has the need for longer intermediate periods during which the buffer cylinder can be recharged.

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