Re: Potable Water - The Third Way.

On Sun, 23 Sep 2007 11:29:46 -0700, "N:dlzc D:aol T:com \(dlzc\)"
<dlzc1@cox.net> wrote:

Angostura I can take or leave:
India Pale Ale works for me,
but not if I've gone for a Burton.

Brian W

Dear Brian Whatcott:

You don't happen to like bitters, do you?  ;>)

David A. Smith

...

I'm probably going to regret responding, but I will anyway, with a
question:

What is the difference in temperature between steam and water,
both at the boiling temperature of water, whatever it may be?

Cooler means lower temperature, right?

OK you can now answer your own question.
I hope.

Brian W

On Sat, 22 Sep 2007 20:43:48 -0700, "N:dlzc D:aol T:com \(dlzc\)"
<dlzc1@cox.net> wrote stuff
and I replied:

Then how do you keep the freshwater tube so cool? It has to be a _lot_
cooler, not so?

Is this a continuous or pulsed process? How do you maintain stasis and
extract fresh water?

If you have a small air bubble, where does the extracted fresh water
go?

etc

Human bevaviour: Bestiality with a brain

Dear OldNick:

Fill the tubes, with a small air bubble in between.  Lift the
tube at the bubble.  No small feat if you are looking to make
hundreds of gallons per day, but a one-shot expense...

David A. Smith

On Sat, 22 Sep 2007 10:55:52 -0500, Brian Whatcott
<betwys1@sbcglobal.net> wrote stuff
and I replied:

But what is the cheap source of getting the vacuum? I figured there
had to be a vacuum, although it was not said. But how do you get it?

Human bevaviour: Bestiality with a brain

Well, at least this respondent Jim, is operating at shall we say the
7th grade level of science/engineering insight.    Like so many other
products of the domestic school system, he seems to have a severe
case of self-esteem syndrome.  

 Still, he may be retrievable, starting with a science demonstration
he may have missed.   Place a beaker of water in a bell-jar and pump
the air out.

When 99% of the air has been pumped out, the water in the beaker is
boiling vigorously, until, in the usual way, the beaker boils dry.
The beaker feels cool to the touch, naturally.

To quote him: "unless I have a cheap source of heating this won't
work..."

    For the $64 prize:   NOW do you get it?

Brian Whatcott    Altus OK

Well no, he obviously hadn't figured that out. Nor can anybody figure
out what is going to hold a column of water 40 ft high as was stated in
the original post. The tubes may be 40 feet but the column of water will
be considerably less. How much less will depend on how much energy is
heating on the hot side and how much energy is cooling on the cool side.
The total amount of energy needed is not going to be any different than
any other distilling method.
    Unless you have the free or cheap sources of cooling and heating at
specific temperatures this isn't going to work any better either.

-jim

Dear Larry:

What Brian left to the reader's imagination, is that the head
space of the tubes is at a near perfect vacuum, flooded only with
water vapor.  You might recall that a perfect vacuum will lift a
column of water about 32 feet, on a high pressure day.  Or had
you not figured that out?

David A. Smith

dlzc <dlzc1@cox.net> wrote in news:1190415672.506271.93890
@k79g2000hse.googlegroups.com:

http://en.wikipedia.org/wiki/Boiling_point

"The boiling point of water is 100 °C (212 °F) at standard pressure. On
top of Mount Everest the pressure is about 260 mbar (26 kPa) so the
boiling point of water is 69 °C. (156.2 °F)."

AT 40' ASL, the boiling point must be down to...to....211.95F!

Larry

Dear Brian Whatcott:

There are ship-board distiller units that use an engine to pull a
vacuum, and the engine's waste heat to boil that water, to generate
drinking water.  A little shorter...

David A. Smith

You've heard all about distilling water, and you've heard all about
reverse osmosis,  but you haven't heard about low-cost, low energy
stills: they are brand new.

Briefly:
Take one forty ft vertical tube filled with saline.
Take one forty ft vertical tube filled with fresh water.
Connect them with a little engineering help - at the top.

The boiling point of water at sea level pressure is about 100 deg C

The boiling point of water at the top of a sealed 40 ft column of
water is near ambient.
So, it doesn't take much heat to boil the brackish water, and have it
pass to the fresh column where it is slightly cooled to hold the near
vacuum conditions at the boiling level.

[An engineering effort of a U of Utah group I think]

Brian Whatcott   Altus OK