LeafyD
Well-known member
Yes, another sad loss in our EV family. She was a feisty, lovely lady. We will miss her presence at our breakfasts. Sending heartfelt condolences to her family.
The biggest problem I see with LH2 is if consumers are supposed to be dispensing it. I'd think they'd need really serious interlocks on the connector to eliminate any possibility of a customer coming in contact with LH2, and the connector itself would be very cold, requiring lots of insulation and making the whole thing very clumsy to use. I can foresee all sorts of safety issues, so while I think LH2 makes sense for some commercial uses, I'd have my doubts about letting the typical untrained car owner anywhere near it. I'd think the stuff's normally dispensed while wearing full protective gear. Anyway, here's some slides showing Linde's take on gaseous versus liquid H2: https://energy.gov/sites/prod/files/2014/07/f17/fcto_2014_h2_trans_dist_wkshp_tamhankar.pdftbleakne said:GRA, thanks for your direct report from the Air Products H2 driver. His cascading tanks make sense, but they also illustrate the problem of dispensing gaseous H2. Your question:
Did First Element say they were looking at switching to LH2 delivery and storage rather than gaseous, or were they talking about LH2 on the cars as well?
He talked about how easy it was to pump LH2 into the car, so I believe he was talking about the car storing it as liquid. Some years ago at a Caltech event BMW displayed a prototype with LH2 storage. The presenter invited me to hold my hand on the tank storing the LH2. I could not feel any sense of cold, but he said it was full. He said the tank insulation was equivalent in R-value to 10s of feet of styrofoam. Apparently since then the cost of this quality of LH2 storage has declined.
Somewhere over in the H2 thread, I provided a link to a study of whether or not H2 could build up to a flammable concentration (4%) in a typical garage given a leak. Even sealing it to a much greater extent than would be the case with a real-world garage (or house FTM), achieving such a concentration was a practical impossibility. Service facilities are even more open. Underground garages may be another matter, but I imagine it all depends on how they're ventilated. Remember, gaseous H2, being such a tiny molecule and lighter than air, will rise and diffuse through just about everything (which is why pure H2 pipelines are so expensive, and they prefer to mix it in low concentrations in NG pipelines). It's not going to pool on the floor.garygid said:For NG or H2, no matter liquid or gas, the production and distribution chain still appears to be energy use intensive, and likely releases a lot of greenhouse gas to the atmosphere. Solar panels to generate electricity ... seems like a better process to me, and distribution is often already in place. In my Garage, I think H2 and the gas water heater would be a ... bad mix. Even at only 1% per day boil off, it seems like too big of a risk in many garages, underground parking, and in typical service facilities.
Gary, found it (or a couple of similar ones), so you can judge for yourself:GRA said:Somewhere over in the H2 thread
https://www.hydrogen.energy.gov/pdfs/safety_biblio/ichs2007/1.1.51.pdfHYDROGEN RELATED RISKS WITHIN A PRIVATE GARAGE:
CONCENTRATION MEASUREMENTS IN A REALISTIC FULL
SCALE EXPERIMENTAL FACILITY
http://ws680.nist.gov/publication/get_pdf.cfm?pub_id=905528HYDROGEN RELEASE AND
COMBUSTION MEASUREMENTS IN A
FULL SCALE GARAGE
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