Hydrogen and fuel cell stationary applications : key findings of modelling and experimental work in the hyper project

International audienceThis paper summarises the results of the research programme in the HYPER project (Installation Permitting Guidance for Hydrogen and Fuel Cells Stationary Applications) [1].The relevance of scientific findings to installation permitting guidelines (IPG) for small stationary hydrogen and fuel cell systems is discussed. A key aim of the activities was to generate new knowledge in the field of hydrogen safety, and, where possible, use this datas a basis to support the recommendations in the IPG. The structure of the paper mirrors the HYPER research programme in that the work is described in terms of the following relevant scenarios: 1) high pressure releases, 2) small foreseeable releases, 3) catastrophic releases, and 4) the effects of walls and barriers. Within each scenario the key objectives, activities and results are presented. The work on high pressure releases sought to provide information for informing safety distances for high pressure components and associated fuel storage, activities on both ignited and unignited jets are reported. A study on small foreseeable releases, which could potentially be controlled through natural or forced ventilation, is described. The aim of the study was to determine the ventilation requirements in enclosures containing fuel cells, such that in the event of a foreseeable leak, the concentration of hydrogen in air for zone 2 ATEX [2] is not exceeded. The hazard potential of a possibly catastrophic hydrogen leakage inside a fuel cell cabinet was investigated using a generic fuel cell enclosure model. The rupture of the hydrogen feed line inside the enclosure was considered and both dispersion and combustion of the resulting hydrogene air mixture were examined for a range of leak rates, and blockage ratios. Finally, the scenario on walls and barriers is discussed; a mitigation strategy to potentially reduce the exposure to jet flames is to incorporate barriers around hydrogen storage equipment. Conclusions of experimental and modelling work which aim to provide guidance on configuration and placement of these walls to minimise overall hazards are presented