Thermally efficient internal support structures in cryogenic applications: A comprehensive review

Internal support structures in cryogenic systems play a vital role in maintaining mechanical stability while limiting conductive heat transfer into the cold regions of the system. Balancing these two requirements presents a significant design challenge, especially in systems operating at very low temperatures where minimizing heat ingress is critical for performance and energy efficiency. A fundamental aspect of meeting this challenge lies in material selection. Materials such as stainless steel and fibre-reinforced composites are widely used due to their high strength, stable mechanical behaviour at cryogenic temperatures, and relatively low thermal conductivity. These properties offer a high strength-to-thermal-conductivity ratio, making them well-suited for cryogenic support applications. This review critically explores the internal support designs employed in cryogenic applications, with a focus on small, medium and large-scale cryogenic systems in different applications. These systems incorporate support structures designed to optimise both thermal and structural performance. Observed design strategies include reducing cross-sectional areas, extending thermal paths, and integrating thermal intercepts to minimize conductive heat transfer. Notably, thermal intercepts have demonstrated the ability to reduce thermal loads by up to a factor of 100 when strategically implemented. In large-scale cryogenic liquid storage systems such as those developed for storing liquid hydrogen (LH2) demonstrate limited adoption of active thermal management techniques. This review highlights this shortcoming and underscores the potential for further advancements in large-scale applications. By consolidating insights from a range of case studies, the paper offers a critical evaluation of current design practices and introduces comprehensive design guidelines for the development of more thermally efficient and mechanically resilient internal support structures in cryogenic systems.