Re: [PSUBS-MAILIST] life support method?

[S W <stephenwhite20@yahoo.com>]

Im not sure how much the air within the submarine is
going to cool since (given we are talking about a
small PSUB) there is a human within it who is
constantly giving off body heat and breathing out
warm, moist air. I don't know for sure, but I would
guess that the pressure differences attributed to the
cooling of the air are probably negligable. The
pressure would have to REALLY drop to cause enough O2
to be released to be toxic. Another reason why a good
O2 and CO2 measuring system is important. The idea is
sound I think. Just curious though,has anyone use or
contemplate a small, electric onboard heater with a
little thermastat?

--- Greg Teiber <wolfe19@megsinet.net> wrote:
> but there is a problem, as the hull cools so will
> the air, and the air will shrink.. and then you'll
> end up with excessively high 02..... you'd need
> somethign to compensate for air temprature
> changes...  so that throws this idea out the
> window....  unless you want to setup a computer to
> add n2 to compensate for temprature.
> 
> *********** REPLY SEPARATOR  ***********
> 
> On 8/4/00 at 9:54 AM Alan D. Secor wrote:
> 
> >You are right, I just didn't follow though with my
> explanation...the 
> >bottom line is your body uses O2 and expels
> CO2...if the CO2 is removed 
> >and the O2 isn't replaced, the net result is a
> reduction of cabin 
> >pressure.
> >
> >Al
> >
> >>
> >>> 2.) If no supplemental O2 were added, the cabin
> >>> pressure would gradually 
> >>> decrease due to the O2 in the air being
> metabolized
> >>> by your body.  You 
> >>> are correct in assuming that if O2 were released
> >>> into the cabin at the 
> >>> rate our body metabolized it, the system would
> >>> remain fairly balanced.
> >>
> >>Actually,
> >>
> >>The decrease in pressure in the cabin is NOT
> caused by
> >>the "metabolism" of 02 by the body, but rather by
> the
> >>conversion of the CO2 to a non-gasous state in the
> >>form of a chemical compound formed between the
> >>absorbant and the CO2 (hence the heat/H20
> emitted).
> >>Respiration requires 02, but yields as a product
> CO2,
> >>which results in no net change in air pressure. It
> is
> >>the scrubber which is decreasing the air pressure,
> not
> >>the person. 
> >>
> >>FOR INSTANCE: (Boring Biology stuff for most)
> >>If you lock a person such as yourself in an
> airtight
> >>room, they will eventually die because their
> bodies
> >>expel C02 (a product of catabolic metabolism) and
> >>convert oxygen to H20 by dumping electrons onto it
> at
> >>the end of the electron transport chain within the
> >>mitochondria of their cells. When you open the
> door of
> >>the room, the air will be saturated with CO2, but
> the
> >>pressure will still be at or very, very near 1
> atm.
> >>Most people think that the CO2 a person breathes
> out
> >>is the oxygen they breathed in with a C attached
> to
> >>it. Actually, it is a completely different oxygen
> that
> >>was stripped of a carbohydrate during a catabolic
> >>reaction.
> >>
> >>
> >>__________________________________________________
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> >>
> >
> >--
> >Alan D. Secor
> >e-mail: secor@btv.ibm.com
> 
> 
> 


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