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<p>Robert,<br>
</p>
<div class="moz-cite-prefix">On 15-11-2021 10:33, Robert.Helling
wrote:<br>
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<blockquote type="cite"
cite="mid:D574887E-C456-416E-8772-44A869389E90@neu.atdotde.de">
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Jan,<br class="">
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<div class="">On 15. Nov 2021, at 09:11, Jan Mulder via
subsurface <<a
href="mailto:subsurface@subsurface-divelog.org"
class="moz-txt-link-freetext" moz-do-not-send="true">subsurface@subsurface-divelog.org</a>>
wrote:</div>
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class="">The idea that there is a ratio between diluent
use and O2 use is flawed. The main driver for O2 use is
time and workload, and for diluent its the dive profile.<span
class="Apple-converted-space"> </span><br class="">
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<div class="">this is clear. I was asking to get an understanding
how bad the error is to ignore that O2 is not only contained in
the O2 bottle but also in diluent. I guess you would want to
know how much O2 your body consumes during the dive. The true
number would be the sum of the O2 from the O2 cylinder plus the
O2 contained in the diluent minus the O2 that was released from
the loop to the water. How bad is the approximation that takes
into account only the O2 from the O2 cylinder? If it’s a few
percent, I would make sense to compute and display that number.
If the error is bigger probably less so.</div>
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<p>I think that the approximation to only take into account the O2
from the O2 cylinder is a good one with only small error. <br>
</p>
<p>I dive a mCCR (Kiss Classic) and adding diluent to the loop is a
very explicit action by the diver. I only add diluent to the loop
when descending (and than only when the loop volume is too low,
and the pO2 is as high as I want it to be). In other words. The
diluent plays a very limited role in the pO2 management. <br>
</p>
<p>In the mCCR, the O2 from the O2 cylinder is added automatically
using a bleed orifice that constantly puts the amount of O2 into
the loop that is close to your metabolized O2. Obviously, the
metabolized O2 also depends on workload, but heavy workload on any
CCR is a bad idea (as the scrubber will not be able to get all the
produced CO2 out of the mix). So, the mCCR diver sets the amount
of O2 bleeded into the loop based on the "normal" workload. And a
nice side effect of this, is that in a very relaxed deco phase of
the dive with low workload, the pO2 rises.</p>
<p>And I agree with Anton that a model that can determine how much
loop volume is metabolized and how much is wasted can be
interesting, but primarily from academic point of view. <br>
</p>
<p>--jan<br>
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