My T1D son and wife are getting ready to spend 2 weeks on the west coast of Costa Rica, in a place where temperature frequently reaches 100F and humidity often hits 90%+. I have been experimenting with different ways to keep insulin cool with as little risk as possible. My latest experiment is the best one, and, I think, a winner. This is what I get after leaving it exposed outside in WI heat for 24 hours (yesterday was mid-80s in shade):
Here is the experiment. I used an insulated double walled stainless steel wide mouth 20 oz bottle from Klean Kanteen:
I can put 4 pens+ with more cartridges in the wide mouth bottle, enough for 2 weeks with plenty to spare. As a note, the 20 oz bottle is the shortest bottle that will fit any size insulin pens - the smaller one, 16 oz size, is not tall enough to fit some pens.
For this experiment, I put 2 pens into the bottle (the bottle had not been cooled to start with, it started at 78F inside ambient temperature). I added 9 pieces of round plastic ice that I had previously frozen:
This is what the whole thing looks like inside the bottle:
I closed the bottle and put it outside in the shade, and left it there for 24 hours. The temperature outside started at 79F and went up to the mid-80s until evening, at which time it went down to about 60F. Today it went back up to 80F when I took it back in after 24 hours outside. After 24 hours of exposure (admittedly, the temperatures weren’t that high), the temperature inside the insulated bottle was still at 35F (see picture above)! The ice balls were not frozen anymore but they were still cold.
Here is a list of the components I used:
Klean Kanteen 20 oz insulated double wall stainless wide mouth bottle: https://www.amazon.com/gp/product/B00UTL9GY6/
Klean Kanteen stainless loop cap (better insulation, shorter bottle): https://www.amazon.com/Klean-Kanteen-Stainless-Steel-Bottle/dp/B0093IKYGK/
plastic ice, i.e. freezable plastic ice balls (I use round ones because (a) I figure it is easier to make them fit in the bottle compared to the squares and (b) I think they will stay frozen longer for reasons of physics ): https://www.amazon.com/gp/product/B00JAGJDUS/
I am optimistic that this setup will withstand a full day in the heat! Any ideas about improving on this?