Glenn - Water ice only holds .5 (or less) BTU/lb-degree, so cooling it
down to zero is only adding another 15 BTU per pound for a total of
159 BTU.

Glenn Ashmore wrote:
I found the best price on ebay. There is a guy on there that sells it.
Apparently pretty reliable because I have suggested him to several people,
all of whom have been very happy with his shipping. The proper term is
"Techni Ice" . In my testing the Techni ice only lasted about 30% longer
than water ice but the temperature averaged about 15F lower. Frozen to 0F
it absorbs about 152 BTU's per pound compared to 176 BTU per pound of water
ice but water ice only absorbs 1 BTU per pound until it gets to 32F and
starts to melt. The gel in Techni Ice starts melting at a lot lower
temperature and is pretty well all melted by the time it reaches 32F.
Apparently it also will absorb more than 1BTU/pound when it is frozen to
very low temperatures although I don't fully understand the physics yet.

The other part of the performance is the Coleman Ultimate Extreme cooler.
It is exactly 1" under the maximum size you can check on an airline and is
about the best insulated mass produced cooler on the market. The "marine"
version cost about $10 more than the regular model but the only real
difference is that it is all white and has an extra set of rope handles
which can handle the rough treatment of baggage handlers. The 50 quart
wheeled model that Wal-Mart carries is nothing like as good.


I keep 5 or 6 sheets in the freezer and just turn the freezer side down to
the lowest setting about 4 days before a trip. All the food goes in Ziploc
bags in the freezer for 3 or 4 days to get it as cold as possible and I pack
the cooler completely full. A towel on the bottom adds a little insulation
to the coldest area and any voids are filled with towels, extra bathing
suits, etc.