Join Date: Nov 2008
Location: Deale, MD
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Re: Keeping insulin cool
Ice is the standard in cooling because it answers most of the questions.
Need longer life, and don't need 32-40F temps?
* Use frozen sports bottles. They stand up to repeated freezing and last much longer than ice.
* Insulate the frozen bottle in addition to placing it in an insulated container. This will slow melting dramatically. A neoprene cozy. It will still keep the container below 80F and last a long time.
* A couple of frozen bottles in a 1/2 gallon insulated drink container can work very well. Place a couple sandwiches and fruit in the top and it provides for a pair for day in a very compact package. No mess.
* A wet sock can do the trick if the wet bulb is below 85F.
The heat of fusion of water (330J/g, or >400J/g if you consider that freezer ice is far below freezing) and the enthalpy of solution of ammonium nitrate (24KJ/mol, 300J/g) are the same; for sailing ice is better. The sole advantage of cold packs is they can be triggered in the field.
(when asked how he reached the starting holds on a difficult rock climbing problem that clearly favored taller climbers - he was perhaps 5'5")
"Well, I just climb up to them."
by Joe Brown, English rock climber
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Last edited by pdqaltair; 08-04-2014 at 08:15 PM.