Reverse Engineering of Cooling Wallet [closed]








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I am looking to reverse engineer the Cooling wallet scenario. For e.g. FRIO has created technology where their inner pouch soaked in water and it cools down and keeps it there for 45h (as per their website). We can do this 1 time activity, but how come it becomes reusable. Does anyone know how create that chemical or what is that chemical they are using.


so basically i want to create a product like shown in this video:
<https://www.youtube.com/watch?v=xjt19lvEwQY>




Not speaking about what FRIO uses, but they are usually based on ordinary latent heat of melting of water, with melting temperature possibly shifted to freezing values by additives, like salts, ethanol, glycerol, ethylenglycol, diethylenglycol.


It is not a big deal to prepare a solution that freezes e.g. at -18 °C, so it keeps near that temperature until it is melted. (The temperature changes as the partial melting/freezing progress affects the liquid composition and the melting/freeing point.)


Similar packages ([ice packs](https://en.wikipedia.org/wiki/Ice_pack)), stored in freezers, are used as cooling packs in insulated containers for transportation of temperature sensitive chemicals, samples or cargo.


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