Navitron Renewable Energy and Sustainability Forum

General Renewable Topics => Inventions, Ideas, Innovation, Bodges etc => Topic started by: Greenbeast on August 24, 2017, 09:37:54 AM



Title: Diy ice packs
Post by: Greenbeast on August 24, 2017, 09:37:54 AM
I'm looking to create my own ice packs so that I get a custom for in my display cool boxes at farmers markets.
I have read some guides and its easy enough, I even have access to a commercial vacuum sealer to make a pro job of it.
My question is for the science boffins ; most articles refer to using alcohol or liquid Soap to prevent complete freezing but one did allude to the fact complete freezing removes the latent heat of fusion therefore requiring more energy to the.
Thoughts?


Title: Re: Diy ice packs
Post by: dhaslam on August 24, 2017, 12:12:06 PM
The gel or alcohol packs seem to be for medical use in order to have flexibility. 


Title: Re: Diy ice packs
Post by: Greenbeast on August 24, 2017, 12:32:15 PM
So would I be best sticking with pure water?


Title: Re: Diy ice packs
Post by: A.L. on August 24, 2017, 02:15:11 PM
hello,

- adding alcohol or soap will lower the freezing point , in proportion to the amount added ( IIRC molal depression of freezing point). I would expect the latent heat of fusion (on a kg or volume basis) to reduced slightly but not to much.

- I would just stick with pure water, leaving space to allow for expansion on freezing (or vacuum pack the ice  ;D)