fuel cell rebreather tech!

[mlavigne]

Not an actual product, and I'm not a rebreather diver yet, but thought some of you guys might find this interesting:

Short circuit for big impact | UDaily

UD researchers report hyper-efficient method for removing carbon dioxide from air

www.udel.edu

They modified a fuel cell to capture CO2 from the air (400-500ppm inlet) at 98-99% effectiveness with hydrogen gas being the only input and water + CO2 being released.

later in the article, they mention large scale rebreathers as a possible use case:
"For example, the UD-patented technology could enable lighter, more efficient carbon dioxide removal devices in spacecraft or submarines, where ongoing filtration is critical."
Based on the stochiometric ratios- you would only need 1/2 the H2 for the amount of CO2 removed, so in theory, you would never need any disposable absorbent, and would just buy H2 and O2 tanks.
If its like most research press releases, we can expect to see it available to buy somewhere between 10 year and never, but fun to think about.

 

[Gone for diving]

Looks neat,,, so if I understand it correctly... all the electricity produced stays inside the fuel cell,?
How many watts are produced?

Be nice if when you breath you can power you dive light as well

 

[mlavigne]

Looks neat,,, so if I understand it correctly... all the electricity produced stays inside the fuel cell,?
How many watts are produced?

Be nice if when you breath you can power you dive light as well

my understanding is that the electricity produced is consumed in the chemical reaction (converting the CO2 to HCO3- to get thru the membrane where it reacts with the H+ to make H2O + CO2, so there is no net energy production- seems like a bit of black magic, but so do regular fuel cells). I couldn't get to the actual paper so I'm going off the PR articles- it is behind a pay wall, despite being funded with taxpayer dollars via ARPA-E (D.O.E.).

 

[TuckerIdaho]

H2 and O2 tanks.

So instead of flooding the loop and killing yourself, you're carrying a bomb on your back.

 

[Wibble]

So instead of flooding the loop and killing yourself, you're carrying a bomb on your back.

Rebreathers are like that. Instead of 23 ways to kill you, that would mean there's 24 ways..!

 

[TuckerIdaho]

Rebreathers are like that. Instead of 23 ways to kill you, that would mean there's 24 ways..!

Now you can take your buddy with you!

 

[Miyaru]

The article only mentions applications in atmospheric environments. 2" by 2" would scrub 2 liters per minute (a fraction of the breathing rate). Take that to 90m depth where the flow increases by a factor 10. What size would be needed and how would that compare to a sofnolime cartridge?

 

[Wibble]

The article only mentions applications in atmospheric environments. 2" by 2" would scrub 2 liters per minute (a fraction of the breathing rate). Take that to 90m depth where the flow increases by a factor 10. What size would be needed and how would that compare to a sofnolime cartridge?

Details, details!

 

[-JD-]

The article only mentions applications in atmospheric environments. 2" by 2" would scrub 2 liters per minute (a fraction of the breathing rate). Take that to 90m depth where the flow increases by a factor 10. What size would be needed and how would that compare to a sofnolime cartridge?

While overall mass flow increases with depth due to increased density, the mass of CO2 is not depth related. How sensitive the efficiency of the technology to the concentration and flow rates is not indicated in the blurb.


Emphasis, mine:

The research team’s results showed that an electrochemical cell measuring 2 inches by 2 inches could continuously remove about 99% of the carbon dioxide found in air flowing at a rate of approximately two liters per minute. An early prototype spiral device about the size of a 12-ounce soda can is capable of filtering 10 liters of air per minute and scrubbing out 98% of the carbon dioxide, the researchers said.

Some napkin calculations:

Something on the order of a soda can will process approx 10 l/m of "air" - Exercise respiratory volume is 40-60 l/m - so lets say a factor of 5x
C02 in the exhaled gas stream is approximately 100x normal air concentration.

So ignoring unknown efficiency factors of concentration/pressure/flow rate: something on the order of 21 cases of soda (500 cans) should do it.



It is a shame. I was envisioning a a fully self contained eco-rebreather.

Mr. Fusion power source
Chess-Evans Desalinator
Electrolysis H2 & O2 production
UD CO2 scrubber

The portable carbon capture system would l have to be worked out, though to be "non-polluting".

 

[OTF]

If you're gonna carry hydrogen you mgiht as well breathe it too, hydrox is the ultimate deep gas (if you can avoid exploding).