New hydrogen filling technology that limits energy loss

A new efficient filling technique has been developed by Teesing, an international supplier of fittings, valves, tubing, systems and assemblies, for ‘hydrogen cars’. Various companies have already been focusing on the development of fuel cells and the production, storage and distribution of hydrogen, and Teesinghas devoted several years to optimizing the critical processes so that ‘driving on hydrogen’ will be practical and sustainable in the future.

Hydrogen has lower energy content than natural gas, which means that the same volume contains less energy. To be precise, three times less than natural gas. Refueling hydrogen at a higher pressure (700 bar) supplies enough energy to give a hydrogen car a respectable range. The hydrogen cylinder will have to be filled at 700 bar within 3 minutes, because most consumers will not wait longer than that at the filling station.

The crux of the problem with filling hydrogen gas at high speed is that hydrogen gas expands when it becomes hot. Currently the solution for this problem is to pre-cool the hydrogen gas, but this  inefficient method results in unnecessary  loss of energy.

Teesing has developed a system called PUsH (pressurizing Using Hydraulics) which counteracts the expansion and where there is no need for pre-cooling. The cylinder is first filled with water at a pressure of 700bar, after which the water is displaced by introducing hydrogen gas into the cylinder at 700 bar. The prototypes have been successfully tested and patents have been issued for the PUsH principle in various countries.

No expansion, no heating, less energy loss and still possible to fill up FCVs quickly up to 700 bar. This method has the additional advantage that no extra action is required to moisten the hydrogen: fuel cells function more efficiently if the hydrogen has been moistened.

The technology, developed by Teesing, has been completed through to level TRL4 and is now about to be validated in a relevant (industrial) application. The demo setup is currently at the Tongji University Shanghai, China. This setup consists of a hydraulic unit, test table with all the instrumentation, pump, control panel, filling compound (nozzle and receptacle) which have been specially developed for this application.