CF-Hydro – FRP-based Hydrogen Transportation and Storage for aerospace applications

The CF-Hydro project aims to develop lightweight construction methods for fiber-reinforced polymer (FRP) piping for hydrogen distribution in aircrafts. The project also explores the feasibility of these methods for manufacturing a cylindrical hydrogen storage system. The focus is on systems for both transcritical (cryo-compressed) and liquid hydrogen (LH₂) distribution and storage. To maintain the required temperature of below -253°C, a double-walled FRP construction is used for both the tank and the pipeline (Figure 1). The inner cylinder stores hydrogen and handles the 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. as 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 to the inner tank. Structural foams are being explored for use as suspension system. An initial test component 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 by IVW. In the patented design, the axial 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 thermal shrinkage of the metallic parts. To avoid leakage of the pressure vessel due to the shrinkage, 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.
 

Summary: The aim of the CF-Hydro research project is the development (TRL3) of lightweight construction methods and processes for the production of CFRP pipelines for hydrogen distribution and a tank for hydrogen storage in aircraft. In each case, the focus is on a system for the transcritical (cryo compressed) and for the liquid distribution/storage of hydrogen.

The project „ Development of an integrated FRP-based hydrogen storage and distribution system for aerospace applications – CF-Hydro“ is funded by the Federal Ministry for Economics and Climate Action on the basis of a decision by the German Bundestag (funding reference 20E2103).