Abstract
Growing international concern over environmental sustainability, together with the urgent need to reduce dependence on carbon-based energy systems, has intensified interest in hydrogen as a flexible and clean energy carrier. In the transportation sector, hydrogen fuel cell vehicles are regarded as a promising solution for achieving low-emission mobility. Nevertheless, the deployment of hydrogen technologies raises significant safety concerns, primarily due to hydrogen’s wide flammability range (4-75% v/v), which necessitates rigorous risk management strategies, especially in enclosed environments such as underground parking garages, where limited ventilation and restricted dispersion may lead to the accumulation of flammable hydrogen-air mixtures.
In this study, computational fluid dynamics (CFD) simulations were conducted to analyse hydrogen dispersion and associated flammability risks in an underground car park. Accidental hydrogen release from a 700-bar onboard storage tank was simulated in an underground parking garage of a residential building (floor area 435 m²) comprising 15 enclosed garage units. The results indicate that natural ventilation strategies, even when implemented with vent areas exceeding current national code requirements, may be insufficient to adequately control and mitigate hydrogen accumulation. These findings highlight the need to revise to existing safety guidelines, both with regard to the adoption of alternative ventilation solutions and the implementation of dedicated parking strategies for hydrogen-powered vehicles.
