Open Access

Current medium to large scale hydrogen storage tanks utilize a double walled tank with vacuum and a low thermal conductivity powder as bulk fill between the two tank walls. This approach offers poor failure resistance and is not economic to build at a large scale. In NICOLHy an alternative cryogenic insulation concept using vacuum insulation panels (VIP) targeted for tanks with capacities from 40 000 m³ to 100 000 m³ is in research. VIPs consist of a gas tight envelope that surrounds a low conductivity core material. Within the envelope, a vacuum is created, which supresses convective heat transfer. Since the core material is typically very low thermal conductivity, while the envelope material has a relatively high thermal conductivity, thermal bridges where two adjoining panels meet cannot be avoided. Modeling of the thermal behaviour of VIPs exists for the building industry, but not for cryogenic temperatures or applications with multiple layers of VIPs, both of which present a new challenge. Here, these challenges and goals for the thermal modeling within the project are presented, alongside an overview over the project itself.

Vacuum insulation panel (VIP) based insulation could present an alternative to the common double walled vacuum insulation for large liquefied Hydrogen (LH2) storage tanks. In this paper a brief introduction on VIPs and the envisioned design of VIP-based LH2-tank insulation is given. The design of a flat plate boil-off calorimeter for the testing of the insulation concept is shown, with regard to thermal design, mechanical design and instrumentation. Finally, an overview over the particular challenges for modelling VIP-based insulation and the proposed testing to be performed on the test rig is presented.

For the future use of liquefied hydrogen (LH2) as a green energy carrier, new concepts for storage tanks and in particular their insulation are necessary. The methodology applied in current LH2 tanks has some disadvantages while manufacturing and operation of large tanks that may be required in the future. While liquefied natural gas tanks exist in the necessary capacities, they are incompatible with LH2 due to its significantly lower storage temperature. In this paper, the possibility of using vacuum insulation panels (VIPs) as an alternative to the conventional double walled, powder filled vacuum insulation is presented. The two systems are introduced and compared on a conceptual level with a focus on the loss of vacuum failure mode. Furthermore, a test rig that enables the testing and quantification of thermal properties of VIP based insulations in ordinary and loss of vacuum conditions is presented. The test rig is a boil-off calorimeter using liquefied nitrogen and features a square cold surface with a side length of 3 m. An overview over the planned testing and its goals is given.

The NICOLHy project aims to develop a novel insulation concept based on Vacuum Insulation Panels (VIP) that enables the safe, cost- and energy efficient storage of large quantities of LH2. Such large scale LH2 storage technology is necessary for establishing a hydrogen economy with dimensions between 40.000 m³ and more than 200.000 m³ of LH2. However, new design concepts are needed because the currently available technologies used in small and medium storages today are not suitable for up-scaling. The main problems prohibiting the up-scaling are the long production time due to the process chain, the low failure tolerance and the spherical shape, which reduces the payload in technical applications by up to 50% compared to other shapes. The novel concept will change these conditions by a system which is modular, open-form, time-and cost efficient while production, operation and service, multi-failure tolerant and applicable for onshore and offshore applications. The presentations shows details to the concept and presents several safety concerns the project has to deal with.