@misc{HajhaririEberweinPerroneetal., author = {Hajhariri, Aliasghar and Eberwein, Robert and Perrone, Luca Pakj and Cozzani, Valerio and Otremba, Frank and Seidlitz, Holger}, title = {Study the impact of spacer at thermal degradation process of MLI-based insulation in fire condition}, series = {Journal of Loss Prevention in the Process Industries}, volume = {92}, journal = {Journal of Loss Prevention in the Process Industries}, publisher = {Elsevier BV}, issn = {0950-4230}, doi = {10.1016/j.jlp.2024.105461}, pages = {240 -- 248}, abstract = {To reduce CO2 emissions, energy carriers such as hydrogen are considered to be a solution. Consumption of hydrogen as a fuel meets several limitations such as its low volumetric energy density in gas phase. To tackle this problem, storage as well as transportation in liquified phase is recommended. To be able to handle this component in liquid phase, an efficient thermal insulation e.g., MLI insulation is required. Different studies have been addressed the vulnerability of such insulation against high thermal loads e.g., in an accident engaging fire. Some of research works have highlighted the importance of considering the MLI thermal degradation focusing on its reflective layer. However, limited number of studies addressed the thermal degradation of spacer material and its effect on the overall heat flux. In this study, through systematic experimental measurements, the effect of thermal loads on glass fleece, glass paper as well as polyester spacers are investigated. The results are reported in various temperature and heat flux profiles. Interpreting the temperature profiles revealed that, as the number of spacers in the medium increases, the peak temperature detectable by the temperature sensor on the measurement plate decreases. Each individual spacer contributes to mitigating the radiative energy received by the measurement plate. Stacks of 20-50 spacers (this is the number of layers in commercial MLI systems applied for liquid hydrogen applications) can potentially reduce the thermal radiation by 1-2 orders of magnitude. An empirical correlation to predict a heat flux attenuation factor is proposed, which is useful for further numerical and analytical studies in the temperature range from ambient to 300 °C.}, language = {en} } @misc{HajhaririEberweinCampleseetal., author = {Hajhariri, Aliasghar and Eberwein, Robert and Camplese, Davide and Scarponi, Giordano Emrys and Cozzani, Valerio and Seidlitz, Holger}, title = {Cryogenic storage safety : experimental evaluation of insulation under extreme conditions}, series = {Journal of loss prevention in the process industries}, volume = {101}, journal = {Journal of loss prevention in the process industries}, publisher = {Elsevier BV}, address = {Amsterdam}, issn = {0950-4230}, doi = {10.1016/j.jlp.2026.105961}, pages = {1 -- 20}, abstract = {Hydrogen is recognized as a keystone of the global energy transition, offering a clean, high-energy-density energy carrier ideal for storage and transportation. Among various storage options, liquid hydrogen (LH2) is especially advantageous for both mobile and stationary applications. However, ensuring the safety and performance of LH2 storage systems under extreme thermal conditions, such as fire exposure, remains an engineering challenge. This study introduces an experimental framework, called the Cryogenic High-Temperature Thermal Vacuum Chamber (CHTTVC), designed to investigate the thermal-hydraulic response of vacuum-insulated cryogenic tanks under fire-like conditions. The apparatus enables evaluation of insulation performance, such as perlite and multilayer insulation (MLI), with a focus on thermal degradation, heat ingress, and vacuum stability. Results indicate that combustible MLIs undergo substantial thermal degradation, leading to heat ingress rates of up to 6.5 kW and the formation of hazardous combustion by-products. In contrast, non-combustible MLIs and bulk insulation materials restrict heat ingress to approximately 3 kW while more effectively preserving vacuum integrity. Combustible MLIs also exhibit pronounced pressure increases in the evacuated section, reaching ∼6 × 104 Pa, nearly six times higher than those observed for non-combustible counterparts. Analysis of effective emissivity further reveals an enhancement in radiative heat transfer, approximately five times, for combustible MLIs following degradation. Additionally, marked thermal stratification develops under both nominal and extreme heat loads, with temperature gradients approaching 10 °C per 100 mm during sustained thermal exposure.}, language = {en} }