Pre Normative Research on the in-door use of fuel cells and hydrogen systems
Key Objectives of the project
HyIndoor addresses knowledge gaps regarding indoor hydrogen accumulations, vented deflagrations, and under-ventilated jet fires. This includes improved criteria for indoor Hydrogen and Fuel Cell systems to avoid hazards; sizing of openings for natural ventilation and specification of forced ventilation systems; and sizing of the vent area for deflagration mitigation. Analytical, numerical and experimental studies in HyIndoor will be guided by the foreseeable release conditions for FC systems in early markets’ power range and enclosure characteristics. The generated knowledge will be translated into safety guidelines, including specific engineering tools supporting their implementation. Recommendations will be formulated for evolutions in EU and international Regulations, Codes and Standards frameworks, to support the safe introduction of HFC in early markets.
HFC technology will first be commercialised for applications where it is market-ready due to superior value and/or comparative competitiveness: backup power supply, portable power generation, powering of materials handling vehicles, etc. These early markets are also strategically important to build up and sustain a manufacturing and supply base for longer term applications.
These applications involving the commercial use of hydrogen as an energy carrier imply very different environments from the existing, mostly industrial, applications. The new applications generally require, by nature or for security reasons, that hydrogen systems be used indoors. Yet existing Regulations, Codes and Standards are very incomplete regarding the practical specification of safety requirements indoors.
HyIndoor addresses the issue of safe indoor use of HFC systems for early markets: it aims to provide scientific and engineering knowledge for the specification of cost-effective means to control hazards, and to develop state-of-the-art guidelines.
The aim of the work is to develop the capability to specify practical means and strategies that will prevent or mitigate the potential consequences of a hydrogen release indoors. This will be implemented with a risk-based approach: the higher the expected frequency of the release, the more stringent the acceptance criteria.
The three physical phenomena that may occur in the event of a release of hydrogen are studied in parallel. The first part of the project assesses the dispersion of hydrogen assessment in an enclosure in different configurations. The main focus of the mitigation strategy is on this aspect, adopting the so-called ATEX hierarchy of primarily preventing the formation and ignition of an explosive atmosphere. Then the project works on ignition of flammable hydrogen-air mixture and its deflagration in a ventilated/vented room or enclosure. Consequence acceptance criteria on the overpressure effects need to be translated into criteria on the spatial distribution of hydrogen and on the venting system size. Final task addresses early ignition and combustion of released hydrogen in an enclosure in the form of jet fire. The behaviour of under-ventilated hydrogen fire in an enclosure is investigated for the first time, including studies of self-extinction of hydrogen jet flame, and prevention of hazardous re-ignition consecutive to an air depletion induced extinction.
These studies focus on hydrogen releases for which a cost-effective and practical consequence mitigation approach can be defined. Those releases for which this is not the case will need to be very reliably prevented. Existing analytical and numerical models are initially used to facilitate the formulation of the test programme, while the experimental results are subsequently used to validate and improve the models and codes when relevant. Finally, the analytical and numerical tools underpin and expand the experimental results and provide valuable information for the development of safety guidelines. These results help to define practical means to limit the consequences to an acceptable level. This takes the form of guidelines and engineering tools to comprehensively address all potentially hazardous hydrogen leaks and associated phenomena for any HFC system, in order to demonstrate that the expected level of safety has been achieved.
The HyIndoor pre-normative research results can then be strategically used to ensure a meaningful and efficient European input in the international Regulations, Codes and Standards (RCS) work, providing Europe with a strategic advantage. All project findings are then transferred and shared to the hydrogen and fuel cell community within the dissemination.
Expected socio and economic impact
HFC technology is expected to constitute a major contribution for environmental protection and rational use of energy. However, hydrogen as an energy carrier requires a sound safety framework of harmonized RCS to reach commercialisation. The generated knowledge will feed into safety guidelines. The experimental work will significantly enhance our understanding of hydrogen dispersion and combustion; the increased predictive ability of CFD modelling will enable its applicability to particular settings without experimental information - particularly useful given the variety of potential applications. Recommendations for normative / regulatory requirements are expected to lead to the adoption of the results by the wider stakeholder community, and their introduction into RCS. A unique initiative, this can give Europe a leading position. The benefits of optimised design and RCS upgrade are expected to significantly improve the prospects of hydrogen as an energy carrier. Additionally, the IP developed in HyIndoor will benefit European industry and research.
 FCH JU Multi Annual Implementation Plan 2009.
 The ATEX directive describes what equipment is allowed in an environment with an explosive atmosphere (to protect employees from explosion risk)
 Industrial experience with transportable pressure vessels shows that dangerous failures can be effectively prevented so that no consequence mitigation is required. The unlikely possibility of such events needs only be considered for the definition of emergency safety plans.