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Mark Borgerson

In article ,
says...
SNIP

You need to get back to the gas law to see where this error lies. You
have to *create* the vacuum. That requires a HUGE increase in volume
for whatever the initial headspace is. For this to happen you need a
much longer tube to start with.

You seem to have missed the fact that I proposed filling the tubes
completely with water so that the initial head space would be zero.
At that point you release the pressure on the water and it falls
to the point where water weight plus vapor pressure equals 1ATm.

At that point, you essentially have two water barometers,
interconnected at the top. One is salty and warm, and
one is fresh and cold. Neither need be too much longer
than 33 feet. The actual height of the water will be
less than 32 feet by a factor dependent on the temperature
of the water in the warm side.

The real practical problem lies in the addition of the dissolved
gases in the seawater to the water vapor in the headspace.
What we have here is a rather inefficient degassing column.
I spent a lot of time degassing seawater while working on
my MS in chemical oceanography. I was trying to measure
the dissolved hydrogen in seawater, and the oxygen, nitrogen,
methane, and other gases kept getting in the way!

Getting rid of the disssolved gases in the headspace and
as bubbles forming on the sides of the tube is going to
be a major headache. As soon as you release the pressure
and start warming the seawater side, bubbles are going
to form all along the tube as the temperature rises and
the pressure is less than 1ATM except at the bottom
of the tube.

Mark Borgerson