DIYbanter - View Single Post

dpb

wrote:
Doug Miller wrote:

... another effect of the salt is that lowering the melting point causes
the phase transition -- which as RJK correctly pointed out is the step
that "eats" the most heat -- to occur much sooner.
I wonder what that means...
Simply that much more energy is absorbed in melting the ice (the phase
transition from solid to liquid) than in raising the temperature of the
mixture.
Still makes no sense to me.
The point is that if your objective is to transfer the heat from the beer to
the ice as rapidly as possible, this is best achieved by melting the ice as
quickly as possible, with the heat contained in the beer -- which in turn is
best achieved by lowering the melting point of the ice by adding salt.

This makes a little more sense.

You *do* know that's why you use salt to melt ice, right?

Sure. Do you still believe that water is more conductive than ice? :-)

If so, I submit you are unqualified in this discussion.

Not that Doug needs anybody to fend for him, that wasn't the point he
made or was intending to make--it was that water is in a practical sense
a better heat transfer mechanism than the ice because can achieve a
better _overall_ heat transfer rate owing to it being liquid and
therefore being in full contact w/ the surface whereas ice isn't...

--