Open Access

This presentation focuses on Liquid Hydrogen (LH2) Boil-Off Gas (BOG) Management, a critical challenge that directly impacts the economic viability, safety, and resilience of future hydrogen transportation networks. The centerpiece of this presentation is the introduction of a Cryogenic Vapor-Cooled Shield (CVCS) as an innovative insulation concept. Advanced insulation technologies are among the most effective solutions for reducing heat ingress, minimizing boil-off losses, improving operational safety, and increasing the efficiency of liquid hydrogen storage and transportation.

The rapid expansion of industries has intensified concerns about global warming, primarily due to increasing CO2 emissions. To mitigate these environmental impacts, the Transition to sustainable energy sources with zero emissions is required. Hydrogen, one of the most abundant elements on Earth, has emerged as a promising energy carrier due to its unique properties, enabling a sustainable and emission-free alternative to conventional fuels. Notably, hydrogen possesses a dual-function capability, allowing energy to be converted into hydrogen and vice versa. Hydrogen can be produced using both renewable and non-renewable energy sources, meaning its carbon footprint varies depending on the production method. To achieve a truly sustainable hydrogen economy and minimize CO2 emissions, electrolysis powered by renewable energy is the preferred production method. However, beyond the Energy source, cost remains a critical factor in making hydrogen a viable alternative to fossil fuels. To establish a competitive hydrogen market, large-scale production is necessary, which in turn demands the development of appropriate storage and transportation infrastructure. While advancements in renewable energy production continue to progress, efficient storage solutions remain a significant challenge. Efficient hydrogen storage is essential to the hydrogen economy. Any storage system must not only optimize energy density but also ensure safety to gain public acceptance. Hydrogen’s inherently low volumetric energy density necessitates compression to high pressures (e.g., 700 bar) to enhance its energy content within a confined volume. Alternatively, liquid hydrogen (LH2) offers significantly higher energy density which makes it more suitable for large-scale storage and transportation. State-of-the-art cryogenic storage systems utilize double-walled tanks with a vacuum-insulated interstitial space, often supplemented with low-conductivity materials such as multi-layer insulation (MLI) to minimize heat transfer. These super-insulating materials are essential for reducing heat ingress particularly at normal operating conditions, defined as the temperature gradient between cryogenic temperatures and ambient room temperature. Even with safety valves designed to Prevent over-pressurization, cryogenic tanks, especially those used in mobile applications, are not immune to failure if the pressure management system malfunctions. In such situations, insulation becomes a critical safeguard, helping to limit heat absorption and prevent the tank from rapid overheating and building up dangerous pressure. While these types of accidents are rare, when they do occur, the consequences can be severe. There are limited studies that investigate the behavior of insulation materials under extreme heat loads, particularly in the event of fire-related accidents. Furthermore, no existing studies comprehensively analyze the transient response of cryogenic storage tanks under such conditions. This PhD thesis aims to address these knowledge gaps through a combination of fundamental experimental investigations and detailed numerical modeling. By studying the behavior of insulation materials under high thermal loads, this Research will provide critical insights into heat transfer mechanisms and enhance the efficiency as well as safety of LH2 storage systems.

Das Kompetenzzentrum H2Safety@BAM forscht zu sicherheitstechnischen Fragestellungen über die gesamte Wertschöpfungskette von Wasserstoff. Der Fokus liegt hierbei insbesondere auf Untersuchungen zu Materialeignung und -kompatibilitäten, neuen Konzepten für die Bauteilsicherheit und -prüfung, Zertifizierungen, Sensortechnik und Analytik sowie der Prozess- und Anlagensicherheit. Das Poster gibt einen Praxisnahen überblick über die Aktivitäten.

The article provides an overview of BAM's modular protection concept and the results of investigations that demonstrate its resistance to destructive tests on gas-filled pressure vessels. During potentially destructive testing involving gas pressurized systems, the hazard posed by high velocity fragments or projectiles must be explicitly accounted for within the safety assessment. In certain cases, this consequence is intentionally induced to enable controlled demonstration, characterization, or measurement. In other cases - such as when evaluating resistance to extraordinary loads - it represents an unintended but probable consequence. In both scenarios, the implementation of protective measures is strongly advisable. These not only protect the test and measurement equipment but also allow for a reduction in safety distances for staff and may even reduce the need for more comprehensive organizational protective measures to protect the surroundings and the environment. Prior to destructive testing of gas-filled pressure vessels, the overpressure wave and dissipation properties as well as the damage resistance of the protective barrier construction must be evaluated. The robustness of the protective cubic system is validated by impact blast tests. The results demonstrate that the modular protective barrier exhibits sufficient resistance to both impact and thermal loading. The study confirms the system’s operational flexibility and its verified robustness with respect to pressure‑wave loading.

As the energy sector undergoes decarbonization, liquefied hydrogen is becoming increasingly important. In addition to large-scale energy imports, it is also well-suited as a fuel for aircraft and, for example, heavy-duty and long-haul road transport applications. A key challenge is the long-term thermal insulation of LH2, which is achieved through a combination of vacuum and multilayer insulation systems. Despite their proven use, there are still gaps in the knowledge of how such systems behave in accident scenarios - including fires - particularly in road transport. The presentation introduces experimental investigations of realistic fire scenarios for commercial vehicles, analyses heat transfer between the fire and a tank, and derives approaches for defining design fires applicable for the approval of tanks. The results contribute to improving the safety, design, and emergency assessment of cryogenic storage systems.