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Re: Fuel Cell technology
Hi Mike,
you're partially right: the fuel cells are a feasible power supply unit for submersibles
(and they're already in use). But it's your proposal about producing the fuel (hydrogen)
by electrolysis (expecially with salt water) which is not a good idea.
The Hydrogen Fuel Cells need oxygen (from air) and hydrogen to produce electric power at
a rate of about 40 to 60% of the energy power stored in the hydrogen.
100KW of hydrogen power will produce about 60KW of electric power.
Heath is also generated in the process and must be eliminated. Some fuel cells systems
work at low temperatures (PEM Fuel Cells usually work at ambient temperature) others need
higher temperatures (up to 90/100° C).
The only waste produced is represented by distilled water.
No mechanical moving parts are involved in the process (except for a small air compressor
needed for some systems requiring air at 2.3bar).
The fuel cell itself is very similar to an accumulator, it's formed by a stack of plates,
some of them being rare or precious metals but the technology is coming to a very thin
laminated (platinum) plate allowing a sensible reduction of costs.
The car you're speaking about is the Daimler-Chrisler NECAR4, actually a Mercedes Class-A
equipped with a fuel cells stack and a methanol reformer. The PEM Fuel Cells used are
from Ballard (Daimler and Ford invested several hundred millions USD in Ballard). They're
extracting hydrogen from methanol as it has an excellent energy storage capacity, it's
easy to handle and it's very easy to convert gasoline stations to methanol stations for
the refueling.
You need a reformer to extract hydrogen from methanol and this implicates some
disavantages: the dimension and weight of the reformer, the energy requested by the
reformer to extract the hydrogen, the time requested to the reformer to start (currently
about ten minutes) and the purity of the hydrogen. This last point avoid the methanol
reforming to be compatible with the Alkaline Fuel Cells (the ones used from 1960 on all
space missions, do you remember Apollo 13?). The small parts of carbon still present in
the hydrogen derived from methanol would quickly intoxicate the fuel cell, actually
killing it. The PEM fuel cells don't suffer this problem but they're an emerging but
still less consolidated technology.
Again, the methanon based system doesn't allow for a true Zero Emission Vehicle as the
reforming process produces carbon monoxide which is very poison and needs a cathalitic
system to reconvert to CO2. So we still have a "little" emission which is not in the pure
hydrogen system.
Conventional storage systems include potentially hazardous pressure cylinders (250bar)
and bulky cryogenic vessels.
More promising, but still very early in the study or development process are the solid
storage systems: metal hydrides and carbon nanofibres. You can image a - not so far -
future when we'll stop to the "gas station" and we'll get a refilling cartridge (about
50x20x15cm, 35Kg in weight) good for the next 3000 or 5000Km at average speed. Absolutely
clean and safe (no problems if the aluminium case broke).
Another, similar, technology is currently available and really promising. The NaOH2 solid
pellets named Powerballs store a quantity of energy similar to methanol but, when the
external polyethilen skin is cut and the powder reacts in water, it produces pure
hydrogen. The process is economical, safe, easy to control, reliable and fully
reciclable. I'm - personally - in the process of using this system to power a fuel cell
driven vehicle for an extreme application. I should receive the first unit in the next
few weeks.
Fuel Cells Technology is an old known process which is becoming a good and real hope for
a better environment in the short future. Hydrogen is a clean and renewable source of
power, its production is still expensive but the industry is confident it'll be available
soon at affordable prices, comparable to traditional gasoline.
Its storage is a problem now, but it's a matter of few years to have a solution available
for private transportation.
Going back to the use of fuel cells technology for p-subs, I'm pretty sure it will
represent a good opportunity but some important and critical issues are related to teh
use of potentially hazardous gases in confined space applications. It's probably too
early now to think about a real and safe application of the current technology to a
personal sub, but as solid hydrogen storage systems will be available at reasonable
costs, I think it'll be a good choice even for p-subs.
Just for curiosity: last year Siemens presented at the Hannover trade show the first fuel
cells driven laptop, the fuel cell has the same size of the original batteries and the
hydrogen is generated at home by a small personal system. The authonomy is very long, not
comparable to the current battery technology. And no hazardous waste is involved.
Last month in Hamburg (Germany) has been opened the first public hydrogen gas station.
You can already buy your hydrogen barbecue set based on powerballs for as low as 300$.
Hydrogen Fuel Cells will substitute current technologies for residential heath and power
source.
Almost all the world car manufacturers are competing and investing big money on fuel
cells technology for the next to come environmental friendly transportation system.
Daimler-Chrisler, Ford, Renault and Toyota appear to be the most advanced in this field.
The Canadian-American Ballard, the Italian DeNora and the British ZEVCO (alkaline fuel
cells) seem to be the most advanced fuel cells manufacturers for car related
applications.
You can find some more info from these pages:
http://www.e-sources.com/fuelcell/urlres.html
http://www.ttcorp.com/nha/thl/
http://www.ecosafe.com/taw/v2i1/fuelcell.htm
Blue skies and deep blues
Paolo
Rick Lucertini wrote:
> Mike here in Malaysia
>
> > [snip] and the local TV channel here showed
> > something on a hydrogen fuel cell, which uses hydrogen gas, [snip]
> > What if you used
> > a fuel cell for a submersible
>
> [snip]
>
> > Any comments? Anybody think it would work besides me?
>
> Hi, Mike
>
> Apparently Ballard Fuel Cells here in Vancouver and the American military agree with
> you. Ballard's been doing work with the US military regarding all sorts of fuel cell
> applications including, I believe, submarines.
>
> As for the technical issues you mentioned, maybe one of the other members can help
> you on that one.
>
> Rick
> --
> Rick Lucertini
> empiricus@sprint.ca
> (Vancouver, Canada)
--
Paolo Velcich
industrial designer
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