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Compressor drives for hydrogen filling stations: scalable, robust and compact
Manuela Kessler
22.04.2024
https://www.boschrexroth.com/de/de/unternehmen/presse/produktportfolio-wasserstoff-25088.html

Servo-hydraulic drives for hydrogen compressors and cryogenic pumps increase efficiency and shorten tank cycles

Together with partner companies from the hydrogen economy, Bosch Rexroth has developed a scalable portfolio of servo-hydraulic compressor drives in the power range between 10 and 280 kW. (Image source: Bosch Rexroth AG)
Within the next six years, several thousand hydrogen filling stations are to go into operation worldwide, thus making an important contribution to the decarbonization of the mobility sector. To this end, Bosch Rexroth has developed a scalable portfolio of servo-hydraulic compressor drives in the power range between 10 and 280 kW together with partner companies from the hydrogen economy. A new cryogenic pump, for example, compresses liquid hydrogen directly to 875 bar, enabling the direct refueling of heavy-duty commercial vehicles within a few minutes.

Long service life and start-stop operation, high efficiency with low hydrogen losses and low operating costs: OEMs and operators are looking for solutions that can be implemented quickly and economically for the cost-effective operation of hydrogen filling stations. Based on its decades of experience in electrohydraulics, Bosch Rexroth has developed tailor-made solutions for a cost-effective hydrogen infrastructure together with partner companies.

To achieve this, the company relies on servo-hydraulic drive technology with a continuously adjustable hydrostatic transmission. The robust hydraulics achieve a long service life. Long-stroke, ATEX-certified compressor drive cylinders increase conveying rates through end-position-optimized control. The portfolio covers the power range between 10 and 280 kW and various applications.

New cryogenic pump: 100 kg of hydrogen can be filled up in 10 minutes

Bosch Rexroth is developing the new electrohydraulically driven cryogenic pump in partnership with FirstElement Fuel, the market leader for the commercial operation of hydrogen filling stations in the United States. With a connected load of 280 kW, it compresses liquid hydrogen to 875 bar for the direct refuelling of heavy trucks. The aim is to refuel the vehicles with 100 kg of hydrogen within 10 minutes. Direct refuelling eliminates the need for intermediate storage at petrol stations. The first filling stations will be equipped from 2025.

Bosch Rexroth also offers variants developed in collaboration with partner companies for medium and lower outputs. The 75 kW CytroCore compressor drive can be used for the compression of both liquid and gaseous hydrogen. In the lower power range of 10 kW, a ready-to-connect self-sufficient axle, CytroForce, drives the compressor cylinders. No specific hydraulics know-how is required for either solution.

Standard modules in hardware and software can be finely scaled

For optimum energy efficiency, Bosch Rexroth relies on the so-called positive displacement control. In contrast to throttle control, which is used in most industrial hydraulic systems, position and force control is implemented by means of servo-hydraulic pump control. This control concept reduces energy consumption by approx. 75%. In addition, the compressor drives require less than one square meter of floor space and are much quieter than conventional drive systems. After the one-time parameterization, they are immediately ready for use. They communicate with the control system of the hydrogen filling station via open interfaces. All modules continuously record operating data and thus create the conditions for systematic condition monitoring and predictive maintenance for maximum availability with the digital service CytroConnect.

Bosch Rexroth can configure the standard drives in its portfolio in hardware and software to suit specific applications, thus meeting the requirements of users precisely. The compressor drives simplify the system architecture and operability of hydrogen filling stations and are suitable for both established companies in the hydrogen economy and newcomers.