Hydrogen Wide Area Monitoring of LH2 Releases

The characterization of liquid hydrogen (LH2) releases has been identified as an international research priority in order to expand the safe use of hydrogen as an energy carrier [1]. The elucidation of LH2 release behavior will require the development of dispersion and other models, guided and validated by empirical field measurements such as those afforded by Hydrogen Wide Area Monitoring (HyWAM). HyWAM can be defined as the quantitative spatial and temporal three-dimensional monitoring of planned or unintentional hydrogen releases. HyWAM strategies are being investigated based on both stand-off methods (e.g., Raman or Schlieren) or by an array of point sensors. The Sensor Laboratory at the National Renewable Sensor Laboratory (NREL) has developed a HyWAM system based upon a distributed array of point sensors. Although various HyWAM strategies have been proposed, the NREL HyWAM has been field demonstrated in real-world indoor and outdoor scenarios, including a release at an LH2 facility [2], and is currently ready for deployment with minimal set up development. The Health and Safety Laboratory (HSL) in the United Kingdom is setting up a series of LH2 releases to characterize the dispersion and pooling behavior of cold hydrogen releases with support provided through the Fuel Cell and Hydrogen Joint Undertaking (FCH JU) Prenormative Research for Safe Use of Liquid Hydrogen (PRESLHY) project [1]. The NREL Sensor Laboratory and HSL have formally committed to collaborate on profiling the LH2 releases. This collaboration will integrate the NREL HyWAM into the HSL LH2 release hardware. A test plan that supports the planned LH2 releases is being developed. The NREL Sensor Laboratory will provide HyWAM modules that will accommodate 32 measurement points for deployment during the HSL PRESLHY LH2 releases. The HSL LH2 releases were scheduled to initiate in the late spring of 2019, but for logistical reasons the release study was rescheduled until early September. The NREL HyWAM will be utilized throughout the current LH2 release study being performed by HSL under PRESLHY, including Work Package 3 (WP3 - Release and Mixing) and subsequent work packages (WP4 - Ignition and WP5 - Combustion). Under the auspices of the PRESLHY WP6 (Implementation) data and findings from the HSL LH2 releases will be made available to stakeholders in the hydrogen community. The integration of the NREL HyWAM into the HSL LH2 release apparatus and its performance as well as some key outcomes of the LH2 release will be discussed in this paper and the corresponding talk at the 2019 International Conference on Hydrogen Safety (ICHS). This is a work in progress, and the actual releases associated with WP3, WP4 and WP5 are currently scheduled to initiate in September 2019, and thus much of the research activity will be after the submission date for this conference paper for ICHS. The presentation at the ICHS will however include some critical outcomes of the LH2 cold plume behavior, as measured by HyWAM. A comprehensive summary of the HSL LH2 Release study will be presented as a series of reports that are to be prepared made available under the PRESLHY project.