In April South Korea based MetaVista raised the world record for the flight time of a electric friven drone by a factor of almost 6, to more than 12 hours!

This was possible only with 390 g liquid stored hydrogen (5.5 liters) and an Intelligent Energy fuel cell. For a nice video with some liquid hydrogen poured out from the cryostat see
https://www.youtube.com/watch?v=LAC8d6b0MF4

Image of MetaVista

NASA is providing three student research teams from different universities with around 6 million dollars over three years to develop alternative propulsion systems for aircrafts. As published in May 2019 University of Illinois is leading the project to develop a novel approach for all-electric aviation. The team is investigating the use of LH2, fuel cells and superconducting motors cooled by LH2.

Within the framework of the program, the students relied on various scientific and non-scientific collaborations, including with the Center for Cryogenic High-Efficiency Electrical Technologies for Aircraft (CHEETA).

On 17th of April first tests with the LN2 cooled DISCHA were performed.

Strong freezing of ambient humidity on the release nozzle has been observed. However, this “snow” is easily removed before each test. The unignited cold DISCHA tests will be completed by end of April.

Experimentalist Mr. Stern

Hunidity frozen on release nozzle

DISCHA set-up with LN2 cooling

The presentations from the 1 day workshop are available online:

https://www.sintef.no/en/events/hydrogen-safety-liquid-hydrogen-workshop/program-and-presentations/

With a delay of a few months because of redesign, new measurement requirements and extensions and delay in component delivery the first experiments in the Release and Distribution phenomena work packages WP3 have been conducted on 31 of January.

The first tests conducted so far are reference tests at ambient temperature which are also meant to check the whole experimental setup, before cooling down the facility to 80 K with liquid nitrogen LN2.

The experiments have been extended to include observation of the mixing in ambient air of the released hydrogen.

The workshop is a joint initiative from HYSAFE and the two projects PRESLHY and SH2IFT, focussing on hydrogen safety, with special emphasis on liquid hydrogen.

Increasing interest in hydrogen in general and more specifically in large volumes has led to a growing need of the understanding of LH2 and related safety aspects of handling and use. Results and plans of the two projects will be presented, and additional invited expert speakers and key stake holders will join.

For further details, the agenda, registration, directions and accommodation see the workshop website https://www.sintef.no/en/events/hydrogen-safety-liquid-hydrogen-workshop/.

Registration on the above website is required by 25 February 2019.

Just have a look at the press releases of the Korean company Hylium: http://www.hylium-industries.com/?act=board&bbs_code=Press.

A “pragmatic” drop test of a LH2 filled vessel you can on youtube https://www.youtube.com/watch?v=zjRiU4XWWog 

Our colleagues and advisors from US DOE provided a link to a quite interesting webinar on LH2 transfer at hydrogen filling stations.

On https://www.energy.gov/eere/fuelcells/downloads/thermodynamic-and-economic-modeling-boil-losses-liquid-hydrogen-handling you can listen to the recording or download the slides.

Interestingly there is a link to a publication and a MATLAB code of LLNL for simulating the transfer of LH2.

In the afternoon of the 18th September 2018 about 40 experts met in Buxton, UK, to summarise the state-of-the-art and derive research priorities for the safe use of liquid hydrogen LH2 in non-industrial settings.

In advance to the workshop a tabled questionnaire for a phenomena identification and ranking exercise was distributed. The evaluation of the results showed that the activities of the PRESLHY project are in general in line with the experts view. However, there were three topics which induced some discussion and potential adjustment of the work program:

1. BLEVE. This phenomenon has been ranked relatively high. On one hand there is some justification for claiming, that for well heat insulated cryovessels, as used for LH2, this phenomenon is less relevant than for LPG, for instance. However, a few historic accident cases showed that there is a potential for such energetic scenarios.
   As there is a recently started small dedicted project on BLEVE phenomenon with PRESLHY partners, advisors respectively, involved, no experiments on the BLEVE topic will be planned in PRESLHY. Moreover, it should be noted, that due to scaling constraints a relevant test program would induce considerable costs.
2. MATERIAL COMPATIBILITY. Also this topic was ranked relatively high. However, from the very beginning PRESLHY explicitely excluded this quite huge domain from the work content for budgetary constraints. It is recommended to treat this topic in a separate dedicated project.
3. JET FIRES. This topic was ranked surprisingly low. In the discussion it turned out that there is the general assumption that the quite well established models for “warm” releases will work well also in the low temperature domain.
   The project will seek to slim down the experimental program for jet fires and rather focus on a few validation cases.

The presentations are available on the workshop website.