CF-Hydro – FRP-based Hydrogen Transportation and Storage

The CF-Hydro project aims to develop lightweight construction methods for manufacturing fiberreinforced polymer (FRP) piping for hydrogen distribution and tanks for hydrogen storage in aircrafts.

The focus is on systems for both cryo-compressed (CcH2) and liquid hydrogen (LH2) distribution and storage. To maintain the required temperature of below -253°C, a double-wall FRP construction is used for the tank and the pipeline (Figure 1). The inner cylinder stores hydrogen and handles internal pressure, while the outer shell provides thermal insulation and connectivity to surrounding systems. The inner cylinder and outer shell are mechanically decoupled, allowing the tank/pipeline to serve as a structural load-bearing component, for e.g., a replacement for spar and stringers in an aircraft wing (Figure 2). For this purpose, an effective suspension and insulation system is being explored to keep the heat and load transfer away from the inner tank/pipeline.

The main focus at IVW is on the development of a tank/ pipeline and a suspension system that is capable of absorbing the loads from the outer shell without transferring them into the inner tank. Structural foams are being explored for use as a suspension system. Initial testing of a composite pipeline with foam suspension and N2 as a medium is under development. The project builds on the design of a novel lightweight hydrogen pressure tank patented at IVW. In the patented design, the loads in the carbon fiber-reinforced polymer (CFRP), which occur due to the high pressure for storing cryo-compressed hydrogen (CcH2), are transferred by metallic boss parts. The low temperature of CcH2 leads to the shrinkage of the metallic parts. To avoid the shrinkage and, therefore a leakage of the pressure vessel, the metallic parts are pre-tensioned. In the case of the LH2 distribution system, thin-walled braided FRP-pipes are planned for the inner pipeline due to low operating pressures.