Info MIT Tech Review Article: Deep Diving on Hydrogen

[tursiops]

Meet the divers trying to figure out how deep humans can go

Figuring out how the human body can withstand underwater pressure has been a problem for over a century, but a ragtag band of divers is experimenting with hydrogen to find out.

www.technologyreview.com

NOTE: This is a preview article in front of a paywall. At best, you can access it once. I think.

If you can't see the original, here is a handmade pdf using PrintFriendly.

 

[Kay Dee]

Excellent. THANKS for posting!

 

[kimh]

I started a thread on this last year, with a video of Simon Mitchell giving a presentation on the hydrogen dive. And there's another video about it here.

 

[drrich2]

Skimmed over it out of curiosity as I'm not technical diver. The focus was achieving dive depths greater than helium. Hydrogen was noted to be highly flammable and pull heat out of your body fast (I'm not sure how much practical impact that has).

I'm posting because I have a question I didn't notice addressed. It's my understanding from past discussions on SB that helium is a limited resource, 'scarce' if you will, and we're using it up. It's also quite expensive for technical divers to purchase, IIRC.

So, I wonder if hydrogen will prove viable to replace helium at the depths and for the purposes helium is now used, and how the cost is apt to compare.

Also, does anyone know whether current rebreathers will be adaptable to its use, or a new model might be needed? I know very little about rebreathers; again, just curious.

 

[JMBL]

@drrich2 : this will give you an idea of the problem : hydrogen + 5%O2 = big kaboom !

So it's easier to mix anything with helium, which neutral. Hydrogen is interesting only for very deep (and so very hypoxic dives) to prevent narcosis and high pressure nervous syndrome (sorry but you'll have to bear with me on that one, English is not my 1st language, so I'm not sure if I use the correct terminology in this instance or not. In French, we use the acronym SNHP).

 

[iliketopetsharks]

Skimmed over it out of curiosity as I'm not technical diver. The focus was achieving dive depths greater than helium. Hydrogen was noted to be highly flammable and pull heat out of your body fast (I'm not sure how much practical impact that has).

I'm posting because I have a question I didn't notice addressed. It's my understanding from past discussions on SB that helium is a limited resource, 'scarce' if you will, and we're using it up. It's also quite expensive for technical divers to purchase, IIRC.

So, I wonder if hydrogen will prove viable to replace helium at the depths and for the purposes helium is now used, and how the cost is apt to compare.

Also, does anyone know whether current rebreathers will be adaptable to its use, or a new model might be needed? I know very little about rebreathers; again, just curious.

The idea was to replace N with H to alleviate HPNS and decrease the gas density of the mixture. H has a considerable narcotic effect, that's why it was used in the first place.

Let's hope for a quantum leap in nuclear fusion research. Then we'd get He as a product of H fusion.

 

[inquis]

The idea was to replace N with H to alleviate HPNS and decrease the gas density of the mixture. H has a considerable narcotic effect, that's why it was used in the first place.

Minor quibble: Hydrogen has only a slight narcotic effect, in spite of a similar solubility as nitrogen. At the pressures involved, it was enough ameliorate HPNS but not enough to incapacitate.

 

[kimh]

It looks like hydrogen will remain an exotic choice used only by a small number of specialists – for extremely deep dives where work of breathing is an issue, and lower-density gas is a critical advantage. Plus the HPNS issue. Barring new developments, hydrogen is just too dangerous / hard to handle.

Also, the cost of helium is not as big an issue for divers using CCRs, because of the way, it’s recycled. OTOH, open-circuit helium is becoming problematic from a cost standpoint.

 

[arkstorm]

Amazing article. Just awesome.

 

[inquis]

Amazing article. Just awesome.

You may be interested in reading Ashley Stewart's article as well:

N=1: The Inside Story of the First-Ever Hydrogen CCR Dive

On Valentine’s Day, Dr. Richard Harris, aka ‘Dr. Harry,’ and the Wetmules made the first reported hydrogen (H2) rebreather dive to a depth of 230m/751 ft, in The Pearse Resurgence, New Zealand. The 13 hour dive, which was nearly two years in planning, was a field test to determine the efficacy...

indepthmag.com