GBM wrote:
"Jeff" wrote in message
Sorry about the late reply - I've been out sailing.

You're making a common mistake. Although the specific heat of water
is 1 calorie per g-deg C, for ice its only about half that, or .5 cal
per g-deg C, or as I stated .5 BTU/lb-deg F. Thus, super cooling ice
add little cooling capacity.

So what happens as the ice heats up from -100F to 32F? The heat capacity
changes as the temperature changes.

I agree though, that there is not much benefit.

It may be better to freeze and cool something else. For example, eutectic
solutions (plates) -see - http://www.epsltd.co.uk/eutecticmain.htm.

We have refrigeration in our icebox, but find that it hardly comes on for
the first day out, because we put frozen freezer packs in the box as well as
a supply of ice cubes (in a container) and frozen drinking water in bottles.

Properties of ice in SI units! :

http://www.engineeringtoolbox.com/ic...ies-d_576.html


Cold plates are certainly convenient, but the cooling capacity is not
as good as plain old ice. The ice packs made of water are generally
the best. You'll notice that the formulation with the best numbers
happens to be very similar to h2o.

http://www.epsltd.co.uk/PlusICE%20Table%20Sept-05.pdf

Of course, if your goal is to keep food frozen, you need something
different.